ruby/yjit_codegen.c at master · ruby/ruby

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	// This file is a fragment of the yjit.o compilation unit. See yjit.c.
	#include "internal.h"
	#include "gc.h"
	#include "internal/compile.h"
	#include "internal/class.h"
	#include "internal/object.h"
	#include "internal/sanitizers.h"
	#include "internal/string.h"
	#include "internal/variable.h"
	#include "internal/re.h"
	#include "probes.h"
	#include "probes_helper.h"
	#include "yjit.h"
	#include "yjit_iface.h"
	#include "yjit_core.h"
	#include "yjit_codegen.h"
	#include "yjit_asm.h"

	// Map from YARV opcodes to code generation functions
	static codegen_fn gen_fns[VM_INSTRUCTION_SIZE] = { NULL };

	// Map from method entries to code generation functions
	static st_table *yjit_method_codegen_table = NULL;

	// Code for exiting back to the interpreter from the leave insn
	static void *leave_exit_code;

	// Code for full logic of returning from C method and exiting to the interpreter
	static uint32_t outline_full_cfunc_return_pos;

	// For implementing global code invalidation
	struct codepage_patch {
	uint32_t inline_patch_pos;
	uint32_t outlined_target_pos;
	};

	typedef rb_darray(struct codepage_patch) patch_array_t;

	static patch_array_t global_inval_patches = NULL;

	// Print the current source location for debugging purposes
	RBIMPL_ATTR_MAYBE_UNUSED()
	static void
	jit_print_loc(jitstate_t jit, const char msg)
	{
	char *ptr;
	long len;
	VALUE path = rb_iseq_path(jit->iseq);
	RSTRING_GETMEM(path, ptr, len);
	fprintf(stderr, "%s %.*s:%u\n", msg, (int)len, ptr, rb_iseq_line_no(jit->iseq, jit->insn_idx));
	}

	// dump an object for debugging purposes
	RBIMPL_ATTR_MAYBE_UNUSED()
	static void
	jit_obj_info_dump(codeblock_t *cb, x86opnd_t opnd) {
	push_regs(cb);
	mov(cb, C_ARG_REGS[0], opnd);
	call_ptr(cb, REG0, (void *)rb_obj_info_dump);
	pop_regs(cb);
	}

	// Get the current instruction's opcode
	static int
	jit_get_opcode(jitstate_t *jit)
	{
	return jit->opcode;
	}

	// Get the index of the next instruction
	static uint32_t
	jit_next_insn_idx(jitstate_t *jit)
	{
	return jit->insn_idx + insn_len(jit_get_opcode(jit));
	}

	// Get an instruction argument by index
	static VALUE
	jit_get_arg(jitstate_t *jit, size_t arg_idx)
	{
	RUBY_ASSERT(arg_idx + 1 < (size_t)insn_len(jit_get_opcode(jit)));
	return *(jit->pc + arg_idx + 1);
	}

	// Load a VALUE into a register and keep track of the reference if it is on the GC heap.
	static void
	jit_mov_gc_ptr(jitstate_t jit, codeblock_t cb, x86opnd_t reg, VALUE ptr)
	{
	RUBY_ASSERT(reg.type == OPND_REG && reg.num_bits == 64);

	// Load the pointer constant into the specified register
	mov(cb, reg, const_ptr_opnd((void*)ptr));

	// The pointer immediate is encoded as the last part of the mov written out
	uint32_t ptr_offset = cb->write_pos - sizeof(VALUE);

	if (!SPECIAL_CONST_P(ptr)) {
	if (!rb_darray_append(&jit->block->gc_object_offsets, ptr_offset)) {
	rb_bug("allocation failed");
	}
	}
	}

	// Check if we are compiling the instruction at the stub PC
	// Meaning we are compiling the instruction that is next to execute
	static bool
	jit_at_current_insn(jitstate_t *jit)
	{
	const VALUE *ec_pc = jit->ec->cfp->pc;
	return (ec_pc == jit->pc);
	}

	// Peek at the nth topmost value on the Ruby stack.
	// Returns the topmost value when n == 0.
	static VALUE
	jit_peek_at_stack(jitstate_t jit, ctx_t ctx, int n)
	{
	RUBY_ASSERT(jit_at_current_insn(jit));

	// Note: this does not account for ctx->sp_offset because
	// this is only available when hitting a stub, and while
	// hitting a stub, cfp->sp needs to be up to date in case
	// codegen functions trigger GC. See :stub-sp-flush:.
	VALUE *sp = jit->ec->cfp->sp;

	return *(sp - 1 - n);
	}

	static VALUE
	jit_peek_at_self(jitstate_t jit, ctx_t ctx)
	{
	return jit->ec->cfp->self;
	}

	RBIMPL_ATTR_MAYBE_UNUSED()
	static VALUE
	jit_peek_at_local(jitstate_t jit, ctx_t ctx, int n)
	{
	RUBY_ASSERT(jit_at_current_insn(jit));

	int32_t local_table_size = jit->iseq->body->local_table_size;
	RUBY_ASSERT(n < (int)jit->iseq->body->local_table_size);

	const VALUE *ep = jit->ec->cfp->ep;
	return ep[-VM_ENV_DATA_SIZE - local_table_size + n + 1];
	}

	// Save the incremented PC on the CFP
	// This is necessary when calleees can raise or allocate
	static void
	jit_save_pc(jitstate_t *jit, x86opnd_t scratch_reg)
	{
	codeblock_t *cb = jit->cb;
	mov(cb, scratch_reg, const_ptr_opnd(jit->pc + insn_len(jit->opcode)));
	mov(cb, mem_opnd(64, REG_CFP, offsetof(rb_control_frame_t, pc)), scratch_reg);
	}

	// Save the current SP on the CFP
	// This realigns the interpreter SP with the JIT SP
	// Note: this will change the current value of REG_SP,
	// which could invalidate memory operands
	static void
	jit_save_sp(jitstate_t jit, ctx_t ctx)
	{
	if (ctx->sp_offset != 0) {
	x86opnd_t stack_pointer = ctx_sp_opnd(ctx, 0);
	codeblock_t *cb = jit->cb;
	lea(cb, REG_SP, stack_pointer);
	mov(cb, member_opnd(REG_CFP, rb_control_frame_t, sp), REG_SP);
	ctx->sp_offset = 0;
	}
	}

	// jit_save_pc() + jit_save_sp(). Should be used before calling a routine that
	// could:
	// - Perform GC allocation
	// - Take the VM lock through RB_VM_LOCK_ENTER()
	// - Perform Ruby method call
	static void
	jit_prepare_routine_call(jitstate_t jit, ctx_t ctx, x86opnd_t scratch_reg)
	{
	jit->record_boundary_patch_point = true;
	jit_save_pc(jit, scratch_reg);
	jit_save_sp(jit, ctx);
	}

	// Record the current codeblock write position for rewriting into a jump into
	// the outlined block later. Used to implement global code invalidation.
	static void
	record_global_inval_patch(const codeblock_t *cb, uint32_t outline_block_target_pos)
	{
	struct codepage_patch patch_point = { cb->write_pos, outline_block_target_pos };
	if (!rb_darray_append(&global_inval_patches, patch_point)) rb_bug("allocation failed");
	}

	static bool jit_guard_known_klass(jitstate_t jit, ctx_t ctx, VALUE known_klass, insn_opnd_t insn_opnd, VALUE sample_instance, const int max_chain_depth, uint8_t *side_exit);

	#if YJIT_STATS

	// Add a comment at the current position in the code block
	static void
	_add_comment(codeblock_t cb, const char comment_str)
	{
	// We can't add comments to the outlined code block
	if (cb == ocb)
	return;

	// Avoid adding duplicate comment strings (can happen due to deferred codegen)
	size_t num_comments = rb_darray_size(yjit_code_comments);
	if (num_comments > 0) {
	struct yjit_comment last_comment = rb_darray_get(yjit_code_comments, num_comments - 1);
	if (last_comment.offset == cb->write_pos && strcmp(last_comment.comment, comment_str) == 0) {
	return;
	}
	}

	struct yjit_comment new_comment = (struct yjit_comment){ cb->write_pos, comment_str };
	rb_darray_append(&yjit_code_comments, new_comment);
	}

	// Comments for generated machine code
	#define ADD_COMMENT(cb, comment) _add_comment((cb), (comment))

	// Verify the ctx's types and mappings against the compile-time stack, self,
	// and locals.
	static void
	verify_ctx(jitstate_t jit, ctx_t ctx)
	{
	// Only able to check types when at current insn
	RUBY_ASSERT(jit_at_current_insn(jit));

	VALUE self_val = jit_peek_at_self(jit, ctx);
	if (type_diff(yjit_type_of_value(self_val), ctx->self_type) == INT_MAX) {
	rb_bug("verify_ctx: ctx type (%s) incompatible with actual value of self: %s", yjit_type_name(ctx->self_type), rb_obj_info(self_val));
	}

	for (int i = 0; i < ctx->stack_size && i < MAX_TEMP_TYPES; i++) {
	temp_type_mapping_t learned = ctx_get_opnd_mapping(ctx, OPND_STACK(i));
	VALUE val = jit_peek_at_stack(jit, ctx, i);
	val_type_t detected = yjit_type_of_value(val);

	if (learned.mapping.kind == TEMP_SELF) {
	if (self_val != val) {
	rb_bug("verify_ctx: stack value was mapped to self, but values did not match\n"
	" stack: %s\n"
	" self: %s",
	rb_obj_info(val),
	rb_obj_info(self_val));
	}
	}

	if (learned.mapping.kind == TEMP_LOCAL) {
	int local_idx = learned.mapping.idx;
	VALUE local_val = jit_peek_at_local(jit, ctx, local_idx);
	if (local_val != val) {
	rb_bug("verify_ctx: stack value was mapped to local, but values did not match\n"
	" stack: %s\n"
	" local %i: %s",
	rb_obj_info(val),
	local_idx,
	rb_obj_info(local_val));
	}
	}

	if (type_diff(detected, learned.type) == INT_MAX) {
	rb_bug("verify_ctx: ctx type (%s) incompatible with actual value on stack: %s", yjit_type_name(learned.type), rb_obj_info(val));
	}
	}

	int32_t local_table_size = jit->iseq->body->local_table_size;
	for (int i = 0; i < local_table_size && i < MAX_TEMP_TYPES; i++) {
	val_type_t learned = ctx->local_types[i];
	VALUE val = jit_peek_at_local(jit, ctx, i);
	val_type_t detected = yjit_type_of_value(val);

	if (type_diff(detected, learned) == INT_MAX) {
	rb_bug("verify_ctx: ctx type (%s) incompatible with actual value of local: %s", yjit_type_name(learned), rb_obj_info(val));
	}
	}
	}

	#else

	#define ADD_COMMENT(cb, comment) ((void)0)
	#define verify_ctx(jit, ctx) ((void)0)

	#endif // if YJIT_STATS

	#if YJIT_STATS

	// Increment a profiling counter with counter_name
	#define GEN_COUNTER_INC(cb, counter_name) _gen_counter_inc(cb, &(yjit_runtime_counters . counter_name))
	static void
	_gen_counter_inc(codeblock_t cb, int64_t counter)
	{
	if (!rb_yjit_opts.gen_stats) return;

	// Use REG1 because there might be return value in REG0
	mov(cb, REG1, const_ptr_opnd(counter));
	cb_write_lock_prefix(cb); // for ractors.
	add(cb, mem_opnd(64, REG1, 0), imm_opnd(1));
	}

	// Increment a counter then take an existing side exit.
	#define COUNTED_EXIT(side_exit, counter_name) _counted_side_exit(side_exit, &(yjit_runtime_counters . counter_name))
	static uint8_t *
	_counted_side_exit(uint8_t existing_side_exit, int64_t counter)
	{
	if (!rb_yjit_opts.gen_stats) return existing_side_exit;

	uint8_t *start = cb_get_ptr(ocb, ocb->write_pos);
	_gen_counter_inc(ocb, counter);
	jmp_ptr(ocb, existing_side_exit);
	return start;
	}

	#else

	#define GEN_COUNTER_INC(cb, counter_name) ((void)0)
	#define COUNTED_EXIT(side_exit, counter_name) side_exit

	#endif // if YJIT_STATS

	// Generate an exit to return to the interpreter
	static uint32_t
	yjit_gen_exit(VALUE exit_pc, ctx_t ctx, codeblock_t *cb)
	{
	const uint32_t code_pos = cb->write_pos;

	ADD_COMMENT(cb, "exit to interpreter");

	// Generate the code to exit to the interpreters
	// Write the adjusted SP back into the CFP
	if (ctx->sp_offset != 0) {
	x86opnd_t stack_pointer = ctx_sp_opnd(ctx, 0);
	lea(cb, REG_SP, stack_pointer);
	mov(cb, member_opnd(REG_CFP, rb_control_frame_t, sp), REG_SP);
	}

	// Update CFP->PC
	mov(cb, RAX, const_ptr_opnd(exit_pc));
	mov(cb, member_opnd(REG_CFP, rb_control_frame_t, pc), RAX);

	// Accumulate stats about interpreter exits
	#if YJIT_STATS
	if (rb_yjit_opts.gen_stats) {
	mov(cb, RDI, const_ptr_opnd(exit_pc));
	call_ptr(cb, RSI, (void *)&yjit_count_side_exit_op);
	}
	#endif

	pop(cb, REG_SP);
	pop(cb, REG_EC);
	pop(cb, REG_CFP);

	mov(cb, RAX, imm_opnd(Qundef));
	ret(cb);

	return code_pos;
	}

	// Generate a continuation for gen_leave() that exits to the interpreter at REG_CFP->pc.
	static uint8_t *
	yjit_gen_leave_exit(codeblock_t *cb)
	{
	uint8_t *code_ptr = cb_get_ptr(cb, cb->write_pos);

	// Note, gen_leave() fully reconstructs interpreter state and leaves the
	// return value in RAX before coming here.

	// Every exit to the interpreter should be counted
	GEN_COUNTER_INC(cb, leave_interp_return);

	pop(cb, REG_SP);
	pop(cb, REG_EC);
	pop(cb, REG_CFP);

	ret(cb);

	return code_ptr;
	}

	// :side-exit:
	// Get an exit for the current instruction in the outlined block. The code
	// for each instruction often begins with several guards before proceeding
	// to do work. When guards fail, an option we have is to exit to the
	// interpreter at an instruction boundary. The piece of code that takes
	// care of reconstructing interpreter state and exiting out of generated
	// code is called the side exit.
	//
	// No guards change the logic for reconstructing interpreter state at the
	// moment, so there is one unique side exit for each context. Note that
	// it's incorrect to jump to the side exit after any ctx stack push/pop operations
	// since they change the logic required for reconstructing interpreter state.
	static uint8_t *
	yjit_side_exit(jitstate_t jit, ctx_t ctx)
	{
	if (!jit->side_exit_for_pc) {
	codeblock_t *ocb = jit->ocb;
	uint32_t pos = yjit_gen_exit(jit->pc, ctx, ocb);
	jit->side_exit_for_pc = cb_get_ptr(ocb, pos);
	}

	return jit->side_exit_for_pc;
	}

	// Generate a runtime guard that ensures the PC is at the start of the iseq,
	// otherwise take a side exit. This is to handle the situation of optional
	// parameters. When a function with optional parameters is called, the entry
	// PC for the method isn't necessarily 0, but we always generated code that
	// assumes the entry point is 0.
	static void
	yjit_pc_guard(codeblock_t cb, const rb_iseq_t iseq)
	{
	RUBY_ASSERT(cb != NULL);

	mov(cb, REG0, member_opnd(REG_CFP, rb_control_frame_t, pc));
	mov(cb, REG1, const_ptr_opnd(iseq->body->iseq_encoded));
	xor(cb, REG0, REG1);

	// xor should impact ZF, so we can jz here
	uint32_t pc_is_zero = cb_new_label(cb, "pc_is_zero");
	jz_label(cb, pc_is_zero);

	// We're not starting at the first PC, so we need to exit.
	GEN_COUNTER_INC(cb, leave_start_pc_non_zero);

	pop(cb, REG_SP);
	pop(cb, REG_EC);
	pop(cb, REG_CFP);

	mov(cb, RAX, imm_opnd(Qundef));
	ret(cb);

	// PC should be at the beginning
	cb_write_label(cb, pc_is_zero);
	cb_link_labels(cb);
	}

	// The code we generate in gen_send_cfunc() doesn't fire the c_return TracePoint event
	// like the interpreter. When tracing for c_return is enabled, we patch the code after
	// the C method return to call into this to fire the event.
	static void
	full_cfunc_return(rb_execution_context_t *ec, VALUE return_value)
	{
	rb_control_frame_t *cfp = ec->cfp;
	RUBY_ASSERT_ALWAYS(cfp == GET_EC()->cfp);
	const rb_callable_method_entry_t *me = rb_vm_frame_method_entry(cfp);

	RUBY_ASSERT_ALWAYS(RUBYVM_CFUNC_FRAME_P(cfp));
	RUBY_ASSERT_ALWAYS(me->def->type == VM_METHOD_TYPE_CFUNC);

	// CHECK_CFP_CONSISTENCY("full_cfunc_return"); TODO revive this

	// Pop the C func's frame and fire the c_return TracePoint event
	// Note that this is the same order as vm_call_cfunc_with_frame().
	rb_vm_pop_frame(ec);
	EXEC_EVENT_HOOK(ec, RUBY_EVENT_C_RETURN, cfp->self, me->def->original_id, me->called_id, me->owner, return_value);
	// Note, this deviates from the interpreter in that users need to enable
	// a c_return TracePoint for this DTrace hook to work. A reasonable change
	// since the Ruby return event works this way as well.
	RUBY_DTRACE_CMETHOD_RETURN_HOOK(ec, me->owner, me->def->original_id);

	// Push return value into the caller's stack. We know that it's a frame that
	// uses cfp->sp because we are patching a call done with gen_send_cfunc().
	ec->cfp->sp[0] = return_value;
	ec->cfp->sp++;
	}

	// Landing code for when c_return tracing is enabled. See full_cfunc_return().
	static void
	gen_full_cfunc_return(void)
	{
	codeblock_t *cb = ocb;
	outline_full_cfunc_return_pos = ocb->write_pos;

	// This chunk of code expect REG_EC to be filled properly and
	// RAX to contain the return value of the C method.

	// Call full_cfunc_return()
	mov(cb, C_ARG_REGS[0], REG_EC);
	mov(cb, C_ARG_REGS[1], RAX);
	call_ptr(cb, REG0, (void *)full_cfunc_return);

	// Count the exit
	GEN_COUNTER_INC(cb, traced_cfunc_return);

	// Return to the interpreter
	pop(cb, REG_SP);
	pop(cb, REG_EC);
	pop(cb, REG_CFP);

	mov(cb, RAX, imm_opnd(Qundef));
	ret(cb);
	}

	/*
	Compile an interpreter entry block to be inserted into an iseq
	Returns `NULL` if compilation fails.
	*/
	static uint8_t *
	yjit_entry_prologue(codeblock_t cb, const rb_iseq_t iseq)
	{
	RUBY_ASSERT(cb != NULL);

	if (cb->write_pos + 1024 >= cb->mem_size) {
	rb_bug("out of executable memory");
	}

	// Align the current write positon to cache line boundaries
	cb_align_pos(cb, 64);

	uint8_t *code_ptr = cb_get_ptr(cb, cb->write_pos);
	ADD_COMMENT(cb, "yjit prolog");

	push(cb, REG_CFP);
	push(cb, REG_EC);
	push(cb, REG_SP);

	// We are passed EC and CFP
	mov(cb, REG_EC, C_ARG_REGS[0]);
	mov(cb, REG_CFP, C_ARG_REGS[1]);

	// Load the current SP from the CFP into REG_SP
	mov(cb, REG_SP, member_opnd(REG_CFP, rb_control_frame_t, sp));

	// Setup cfp->jit_return
	// TODO: this could use an IP relative LEA instead of an 8 byte immediate
	mov(cb, REG0, const_ptr_opnd(leave_exit_code));
	mov(cb, member_opnd(REG_CFP, rb_control_frame_t, jit_return), REG0);

	// We're compiling iseqs that we expect to start at `insn_idx`. But in
	// the case of optional parameters, the interpreter can set the pc to a
	// different location depending on the optional parameters. If an iseq
	// has optional parameters, we'll add a runtime check that the PC we've
	// compiled for is the same PC that the interpreter wants us to run with.
	// If they don't match, then we'll take a side exit.
	if (iseq->body->param.flags.has_opt) {
	yjit_pc_guard(cb, iseq);
	}

	return code_ptr;
	}

	// Generate code to check for interrupts and take a side-exit.
	// Warning: this function clobbers REG0
	static void
	yjit_check_ints(codeblock_t cb, uint8_t side_exit)
	{
	// Check for interrupts
	// see RUBY_VM_CHECK_INTS(ec) macro
	ADD_COMMENT(cb, "RUBY_VM_CHECK_INTS(ec)");
	mov(cb, REG0_32, member_opnd(REG_EC, rb_execution_context_t, interrupt_mask));
	not(cb, REG0_32);
	test(cb, member_opnd(REG_EC, rb_execution_context_t, interrupt_flag), REG0_32);
	jnz_ptr(cb, side_exit);
	}

	// Generate a stubbed unconditional jump to the next bytecode instruction.
	// Blocks that are part of a guard chain can use this to share the same successor.
	static void
	jit_jump_to_next_insn(jitstate_t jit, const ctx_t current_context)
	{
	// Reset the depth since in current usages we only ever jump to to
	// chain_depth > 0 from the same instruction.
	ctx_t reset_depth = *current_context;
	reset_depth.chain_depth = 0;

	blockid_t jump_block = { jit->iseq, jit_next_insn_idx(jit) };

	// We are at the end of the current instruction. Record the boundary.
	if (jit->record_boundary_patch_point) {
	uint32_t exit_pos = yjit_gen_exit(jit->pc + insn_len(jit->opcode), &reset_depth, ocb);
	record_global_inval_patch(cb, exit_pos);
	jit->record_boundary_patch_point = false;
	}

	// Generate the jump instruction
	gen_direct_jump(
	jit,
	&reset_depth,
	jump_block
	);
	}

	// Compile a sequence of bytecode instructions for a given basic block version
	static void
	yjit_gen_block(block_t block, rb_execution_context_t ec)
	{
	RUBY_ASSERT(cb != NULL);
	RUBY_ASSERT(block != NULL);
	RUBY_ASSERT(!(block->blockid.idx == 0 && block->ctx.stack_size > 0));

	// Copy the block's context to avoid mutating it
	ctx_t ctx_copy = block->ctx;
	ctx_t *ctx = &ctx_copy;

	const rb_iseq_t *iseq = block->blockid.iseq;
	uint32_t insn_idx = block->blockid.idx;
	const uint32_t starting_insn_idx = insn_idx;

	// NOTE: if we are ever deployed in production, we
	// should probably just log an error and return NULL here,
	// so we can fail more gracefully
	if (cb->write_pos + 1024 >= cb->mem_size) {
	rb_bug("out of executable memory");
	}
	if (ocb->write_pos + 1024 >= ocb->mem_size) {
	rb_bug("out of executable memory (outlined block)");
	}

	// Initialize a JIT state object
	jitstate_t jit = {
	.cb = cb,
	.ocb = ocb,
	.block = block,
	.iseq = iseq,
	.ec = ec
	};

	// Mark the start position of the block
	block->start_pos = cb->write_pos;

	// For each instruction to compile
	for (;;) {
	// Get the current pc and opcode
	VALUE *pc = yjit_iseq_pc_at_idx(iseq, insn_idx);
	int opcode = yjit_opcode_at_pc(iseq, pc);
	RUBY_ASSERT(opcode >= 0 && opcode < VM_INSTRUCTION_SIZE);

	// opt_getinlinecache wants to be in a block all on its own. Cut the block short
	// if we run into it. See gen_opt_getinlinecache for details.
	if (opcode == BIN(opt_getinlinecache) && insn_idx > starting_insn_idx) {
	jit_jump_to_next_insn(&jit, ctx);
	break;
	}

	// Set the current instruction
	jit.insn_idx = insn_idx;
	jit.opcode = opcode;
	jit.pc = pc;
	jit.side_exit_for_pc = NULL;

	// If previous instruction requested to record the boundary
	if (jit.record_boundary_patch_point) {
	// Generate an exit to this instruction and record it
	uint32_t exit_pos = yjit_gen_exit(jit.pc, ctx, ocb);
	record_global_inval_patch(cb, exit_pos);
	jit.record_boundary_patch_point = false;
	}

	// Verify our existing assumption (DEBUG)
	if (jit_at_current_insn(&jit)) {
	verify_ctx(&jit, ctx);
	}

	// Lookup the codegen function for this instruction
	codegen_fn gen_fn = gen_fns[opcode];
	if (!gen_fn) {
	// If we reach an unknown instruction,
	// exit to the interpreter and stop compiling
	yjit_gen_exit(jit.pc, ctx, cb);
	break;
	}

	if (0) {
	fprintf(stderr, "compiling %d: %s\n", insn_idx, insn_name(opcode));
	print_str(cb, insn_name(opcode));
	}

	// :count-placement:
	// Count bytecode instructions that execute in generated code.
	// Note that the increment happens even when the output takes side exit.
	GEN_COUNTER_INC(cb, exec_instruction);

	// Add a comment for the name of the YARV instruction
	ADD_COMMENT(cb, insn_name(opcode));

	// Call the code generation function
	codegen_status_t status = gen_fn(&jit, ctx, cb);

	// For now, reset the chain depth after each instruction as only the
	// first instruction in the block can concern itself with the depth.
	ctx->chain_depth = 0;

	// If we can't compile this instruction
	// exit to the interpreter and stop compiling
	if (status == YJIT_CANT_COMPILE) {
	// TODO: if the codegen function makes changes to ctx and then return YJIT_CANT_COMPILE,
	// the exit this generates would be wrong. We could save a copy of the entry context
	// and assert that ctx is the same here.
	yjit_gen_exit(jit.pc, ctx, cb);
	break;
	}

	// Move to the next instruction to compile
	insn_idx += insn_len(opcode);

	// If the instruction terminates this block
	if (status == YJIT_END_BLOCK) {
	break;
	}
	}

	// Mark the end position of the block
	block->end_pos = cb->write_pos;

	// Store the index of the last instruction in the block
	block->end_idx = insn_idx;

	// We currently can't handle cases where the request is for a block that
	// doesn't go to the next instruction.
	RUBY_ASSERT(!jit.record_boundary_patch_point);

	if (YJIT_DUMP_MODE >= 2) {
	// Dump list of compiled instrutions
	fprintf(stderr, "Compiled the following for iseq=%p:\n", (void *)iseq);
	for (uint32_t idx = block->blockid.idx; idx < insn_idx; ) {
	int opcode = yjit_opcode_at_pc(iseq, yjit_iseq_pc_at_idx(iseq, idx));
	fprintf(stderr, " %04d %s\n", idx, insn_name(opcode));
	idx += insn_len(opcode);
	}
	}
	}

	static codegen_status_t gen_opt_send_without_block(jitstate_t jit, ctx_t ctx, codeblock_t *cb);

	static codegen_status_t
	gen_nop(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Do nothing
	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_dup(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Get the top value and its type
	x86opnd_t dup_val = ctx_stack_pop(ctx, 0);
	temp_type_mapping_t mapping = ctx_get_opnd_mapping(ctx, OPND_STACK(0));

	// Push the same value on top
	x86opnd_t loc0 = ctx_stack_push_mapping(ctx, mapping);
	mov(cb, REG0, dup_val);
	mov(cb, loc0, REG0);

	return YJIT_KEEP_COMPILING;
	}

	// duplicate stack top n elements
	static codegen_status_t
	gen_dupn(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	rb_num_t n = (rb_num_t)jit_get_arg(jit, 0);

	// In practice, seems to be only used for n==2
	if (n != 2) {
	return YJIT_CANT_COMPILE;
	}

	x86opnd_t opnd1 = ctx_stack_opnd(ctx, 1);
	x86opnd_t opnd0 = ctx_stack_opnd(ctx, 0);
	temp_type_mapping_t mapping1 = ctx_get_opnd_mapping(ctx, OPND_STACK(1));
	temp_type_mapping_t mapping0 = ctx_get_opnd_mapping(ctx, OPND_STACK(0));

	x86opnd_t dst1 = ctx_stack_push_mapping(ctx, mapping1);
	mov(cb, REG0, opnd1);
	mov(cb, dst1, REG0);

	x86opnd_t dst0 = ctx_stack_push_mapping(ctx, mapping0);
	mov(cb, REG0, opnd0);
	mov(cb, dst0, REG0);

	return YJIT_KEEP_COMPILING;
	}

	static void
	stack_swap(ctx_t ctx, codeblock_t cb, int offset0, int offset1, x86opnd_t reg0, x86opnd_t reg1)
	{
	x86opnd_t opnd0 = ctx_stack_opnd(ctx, offset0);
	x86opnd_t opnd1 = ctx_stack_opnd(ctx, offset1);

	temp_type_mapping_t mapping0 = ctx_get_opnd_mapping(ctx, OPND_STACK(offset0));
	temp_type_mapping_t mapping1 = ctx_get_opnd_mapping(ctx, OPND_STACK(offset1));

	mov(cb, reg0, opnd0);
	mov(cb, reg1, opnd1);
	mov(cb, opnd0, reg1);
	mov(cb, opnd1, reg0);

	ctx_set_opnd_mapping(ctx, OPND_STACK(offset0), mapping1);
	ctx_set_opnd_mapping(ctx, OPND_STACK(offset1), mapping0);
	}

	// Swap top 2 stack entries
	static codegen_status_t
	gen_swap(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	stack_swap(ctx , cb, 0, 1, REG0, REG1);
	return YJIT_KEEP_COMPILING;
	}

	// set Nth stack entry to stack top
	static codegen_status_t
	gen_setn(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	rb_num_t n = (rb_num_t)jit_get_arg(jit, 0);

	// Set the destination
	x86opnd_t top_val = ctx_stack_pop(ctx, 0);
	x86opnd_t dst_opnd = ctx_stack_opnd(ctx, (int32_t)n);
	mov(cb, REG0, top_val);
	mov(cb, dst_opnd, REG0);

	temp_type_mapping_t mapping = ctx_get_opnd_mapping(ctx, OPND_STACK(0));
	ctx_set_opnd_mapping(ctx, OPND_STACK(n), mapping);

	return YJIT_KEEP_COMPILING;
	}

	// get nth stack value, then push it
	static codegen_status_t
	gen_topn(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	int32_t n = (int32_t)jit_get_arg(jit, 0);

	// Get top n type / operand
	x86opnd_t top_n_val = ctx_stack_opnd(ctx, n);
	temp_type_mapping_t mapping = ctx_get_opnd_mapping(ctx, OPND_STACK(n));

	x86opnd_t loc0 = ctx_stack_push_mapping(ctx, mapping);
	mov(cb, REG0, top_n_val);
	mov(cb, loc0, REG0);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_pop(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Decrement SP
	ctx_stack_pop(ctx, 1);
	return YJIT_KEEP_COMPILING;
	}

	// Pop n values off the stack
	static codegen_status_t
	gen_adjuststack(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	rb_num_t n = (rb_num_t)jit_get_arg(jit, 0);
	ctx_stack_pop(ctx, n);
	return YJIT_KEEP_COMPILING;
	}

	// new array initialized from top N values
	static codegen_status_t
	gen_newarray(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	rb_num_t n = (rb_num_t)jit_get_arg(jit, 0);

	// Save the PC and SP because we are allocating
	jit_prepare_routine_call(jit, ctx, REG0);

	x86opnd_t values_ptr = ctx_sp_opnd(ctx, -(sizeof(VALUE) * (uint32_t)n));

	// call rb_ec_ary_new_from_values(struct rb_execution_context_struct ec, long n, const VALUE elts);
	mov(cb, C_ARG_REGS[0], REG_EC);
	mov(cb, C_ARG_REGS[1], imm_opnd(n));
	lea(cb, C_ARG_REGS[2], values_ptr);
	call_ptr(cb, REG0, (void *)rb_ec_ary_new_from_values);

	ctx_stack_pop(ctx, n);
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_ARRAY);
	mov(cb, stack_ret, RAX);

	return YJIT_KEEP_COMPILING;
	}

	// dup array
	static codegen_status_t
	gen_duparray(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	VALUE ary = jit_get_arg(jit, 0);

	// Save the PC and SP because we are allocating
	jit_prepare_routine_call(jit, ctx, REG0);

	// call rb_ary_resurrect(VALUE ary);
	jit_mov_gc_ptr(jit, cb, C_ARG_REGS[0], ary);
	call_ptr(cb, REG0, (void *)rb_ary_resurrect);

	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_ARRAY);
	mov(cb, stack_ret, RAX);

	return YJIT_KEEP_COMPILING;
	}

	VALUE rb_vm_splat_array(VALUE flag, VALUE ary);

	// call to_a on the array on the stack
	static codegen_status_t
	gen_splatarray(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	VALUE flag = (VALUE) jit_get_arg(jit, 0);

	// Save the PC and SP because the callee may allocate
	// Note that this modifies REG_SP, which is why we do it first
	jit_prepare_routine_call(jit, ctx, REG0);

	// Get the operands from the stack
	x86opnd_t ary_opnd = ctx_stack_pop(ctx, 1);

	// Call rb_vm_splat_array(flag, ary)
	jit_mov_gc_ptr(jit, cb, C_ARG_REGS[0], flag);
	mov(cb, C_ARG_REGS[1], ary_opnd);
	call_ptr(cb, REG1, (void *) rb_vm_splat_array);

	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_ARRAY);
	mov(cb, stack_ret, RAX);

	return YJIT_KEEP_COMPILING;
	}

	// new range initialized from top 2 values
	static codegen_status_t
	gen_newrange(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	rb_num_t flag = (rb_num_t)jit_get_arg(jit, 0);

	// rb_range_new() allocates and can raise
	jit_prepare_routine_call(jit, ctx, REG0);

	// val = rb_range_new(low, high, (int)flag);
	mov(cb, C_ARG_REGS[0], ctx_stack_opnd(ctx, 1));
	mov(cb, C_ARG_REGS[1], ctx_stack_opnd(ctx, 0));
	mov(cb, C_ARG_REGS[2], imm_opnd(flag));
	call_ptr(cb, REG0, (void *)rb_range_new);

	ctx_stack_pop(ctx, 2);
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_HEAP);
	mov(cb, stack_ret, RAX);

	return YJIT_KEEP_COMPILING;
	}

	static void
	guard_object_is_heap(codeblock_t cb, x86opnd_t object_opnd, ctx_t ctx, uint8_t *side_exit)
	{
	ADD_COMMENT(cb, "guard object is heap");

	// Test that the object is not an immediate
	test(cb, object_opnd, imm_opnd(RUBY_IMMEDIATE_MASK));
	jnz_ptr(cb, side_exit);

	// Test that the object is not false or nil
	cmp(cb, object_opnd, imm_opnd(Qnil));
	RUBY_ASSERT(Qfalse < Qnil);
	jbe_ptr(cb, side_exit);
	}

	static inline void
	guard_object_is_array(codeblock_t cb, x86opnd_t object_opnd, x86opnd_t flags_opnd, ctx_t ctx, uint8_t *side_exit)
	{
	ADD_COMMENT(cb, "guard object is array");

	// Pull out the type mask
	mov(cb, flags_opnd, member_opnd(object_opnd, struct RBasic, flags));
	and(cb, flags_opnd, imm_opnd(RUBY_T_MASK));

	// Compare the result with T_ARRAY
	cmp(cb, flags_opnd, imm_opnd(T_ARRAY));
	jne_ptr(cb, side_exit);
	}

	// push enough nils onto the stack to fill out an array
	static codegen_status_t
	gen_expandarray(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	int flag = (int) jit_get_arg(jit, 1);

	// If this instruction has the splat flag, then bail out.
	if (flag & 0x01) {
	GEN_COUNTER_INC(cb, expandarray_splat);
	return YJIT_CANT_COMPILE;
	}

	// If this instruction has the postarg flag, then bail out.
	if (flag & 0x02) {
	GEN_COUNTER_INC(cb, expandarray_postarg);
	return YJIT_CANT_COMPILE;
	}

	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	// num is the number of requested values. If there aren't enough in the
	// array then we're going to push on nils.
	int num = (int)jit_get_arg(jit, 0);
	val_type_t array_type = ctx_get_opnd_type(ctx, OPND_STACK(0));
	x86opnd_t array_opnd = ctx_stack_pop(ctx, 1);

	if (array_type.type == ETYPE_NIL) {
	// special case for a, b = nil pattern
	// push N nils onto the stack
	for (int i = 0; i < num; i++) {
	x86opnd_t push = ctx_stack_push(ctx, TYPE_NIL);
	mov(cb, push, imm_opnd(Qnil));
	}
	return YJIT_KEEP_COMPILING;
	}

	// Move the array from the stack into REG0 and check that it's an array.
	mov(cb, REG0, array_opnd);
	guard_object_is_heap(cb, REG0, ctx, COUNTED_EXIT(side_exit, expandarray_not_array));
	guard_object_is_array(cb, REG0, REG1, ctx, COUNTED_EXIT(side_exit, expandarray_not_array));

	// If we don't actually want any values, then just return.
	if (num == 0) {
	return YJIT_KEEP_COMPILING;
	}

	// Pull out the embed flag to check if it's an embedded array.
	x86opnd_t flags_opnd = member_opnd(REG0, struct RBasic, flags);
	mov(cb, REG1, flags_opnd);

	// Move the length of the embedded array into REG1.
	and(cb, REG1, imm_opnd(RARRAY_EMBED_LEN_MASK));
	shr(cb, REG1, imm_opnd(RARRAY_EMBED_LEN_SHIFT));

	// Conditionally move the length of the heap array into REG1.
	test(cb, flags_opnd, imm_opnd(RARRAY_EMBED_FLAG));
	cmovz(cb, REG1, member_opnd(REG0, struct RArray, as.heap.len));

	// Only handle the case where the number of values in the array is greater
	// than or equal to the number of values requested.
	cmp(cb, REG1, imm_opnd(num));
	jl_ptr(cb, COUNTED_EXIT(side_exit, expandarray_rhs_too_small));

	// Load the address of the embedded array into REG1.
	// (struct RArray *)(obj)->as.ary
	lea(cb, REG1, member_opnd(REG0, struct RArray, as.ary));

	// Conditionally load the address of the heap array into REG1.
	// (struct RArray *)(obj)->as.heap.ptr
	test(cb, flags_opnd, imm_opnd(RARRAY_EMBED_FLAG));
	cmovz(cb, REG1, member_opnd(REG0, struct RArray, as.heap.ptr));

	// Loop backward through the array and push each element onto the stack.
	for (int32_t i = (int32_t) num - 1; i >= 0; i--) {
	x86opnd_t top = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, REG0, mem_opnd(64, REG1, i * SIZEOF_VALUE));
	mov(cb, top, REG0);
	}

	return YJIT_KEEP_COMPILING;
	}

	// new hash initialized from top N values
	static codegen_status_t
	gen_newhash(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	rb_num_t n = (rb_num_t)jit_get_arg(jit, 0);

	if (n == 0) {
	// Save the PC and SP because we are allocating
	jit_prepare_routine_call(jit, ctx, REG0);

	// val = rb_hash_new();
	call_ptr(cb, REG0, (void *)rb_hash_new);

	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_HASH);
	mov(cb, stack_ret, RAX);

	return YJIT_KEEP_COMPILING;
	}
	else {
	return YJIT_CANT_COMPILE;
	}
	}

	static codegen_status_t
	gen_putnil(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Write constant at SP
	x86opnd_t stack_top = ctx_stack_push(ctx, TYPE_NIL);
	mov(cb, stack_top, imm_opnd(Qnil));
	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_putobject(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	VALUE arg = jit_get_arg(jit, 0);

	if (FIXNUM_P(arg))
	{
	// Keep track of the fixnum type tag
	x86opnd_t stack_top = ctx_stack_push(ctx, TYPE_FIXNUM);
	x86opnd_t imm = imm_opnd((int64_t)arg);

	// 64-bit immediates can't be directly written to memory
	if (imm.num_bits <= 32)
	{
	mov(cb, stack_top, imm);
	}
	else
	{
	mov(cb, REG0, imm);
	mov(cb, stack_top, REG0);
	}
	}
	else if (arg == Qtrue \|\| arg == Qfalse)
	{
	x86opnd_t stack_top = ctx_stack_push(ctx, TYPE_IMM);
	mov(cb, stack_top, imm_opnd((int64_t)arg));
	}
	else
	{
	// Load the value to push into REG0
	// Note that this value may get moved by the GC
	VALUE put_val = jit_get_arg(jit, 0);
	jit_mov_gc_ptr(jit, cb, REG0, put_val);

	val_type_t val_type = yjit_type_of_value(put_val);

	// Write argument at SP
	x86opnd_t stack_top = ctx_stack_push(ctx, val_type);
	mov(cb, stack_top, REG0);
	}

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_putstring(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	VALUE put_val = jit_get_arg(jit, 0);

	// Save the PC and SP because the callee will allocate
	jit_prepare_routine_call(jit, ctx, REG0);

	mov(cb, C_ARG_REGS[0], REG_EC);
	jit_mov_gc_ptr(jit, cb, C_ARG_REGS[1], put_val);
	call_ptr(cb, REG0, (void *)rb_ec_str_resurrect);

	x86opnd_t stack_top = ctx_stack_push(ctx, TYPE_STRING);
	mov(cb, stack_top, RAX);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_putobject_int2fix(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	int opcode = jit_get_opcode(jit);
	int cst_val = (opcode == BIN(putobject_INT2FIX_0_))? 0:1;

	// Write constant at SP
	x86opnd_t stack_top = ctx_stack_push(ctx, TYPE_FIXNUM);
	mov(cb, stack_top, imm_opnd(INT2FIX(cst_val)));

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_putself(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Load self from CFP
	mov(cb, REG0, member_opnd(REG_CFP, rb_control_frame_t, self));

	// Write it on the stack
	x86opnd_t stack_top = ctx_stack_push_self(ctx);
	mov(cb, stack_top, REG0);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_putspecialobject(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	enum vm_special_object_type type = (enum vm_special_object_type)jit_get_arg(jit, 0);

	if (type == VM_SPECIAL_OBJECT_VMCORE) {
	x86opnd_t stack_top = ctx_stack_push(ctx, TYPE_HEAP);
	jit_mov_gc_ptr(jit, cb, REG0, rb_mRubyVMFrozenCore);
	mov(cb, stack_top, REG0);
	return YJIT_KEEP_COMPILING;
	}
	else {
	// TODO: implement for VM_SPECIAL_OBJECT_CBASE and
	// VM_SPECIAL_OBJECT_CONST_BASE
	return YJIT_CANT_COMPILE;
	}
	}

	// Get EP at level from CFP
	static void
	gen_get_ep(codeblock_t *cb, x86opnd_t reg, uint32_t level)
	{
	// Load environment pointer EP from CFP
	mov(cb, reg, member_opnd(REG_CFP, rb_control_frame_t, ep));

	while (level--) {
	// Get the previous EP from the current EP
	// See GET_PREV_EP(ep) macro
	// VALUE prev_ep = ((VALUE )((ep)[VM_ENV_DATA_INDEX_SPECVAL] & ~0x03))
	mov(cb, reg, mem_opnd(64, REG0, SIZEOF_VALUE * VM_ENV_DATA_INDEX_SPECVAL));
	and(cb, reg, imm_opnd(~0x03));
	}
	}

	// Compute the index of a local variable from its slot index
	static uint32_t
	slot_to_local_idx(const rb_iseq_t *iseq, int32_t slot_idx)
	{
	// Convoluted rules from local_var_name() in iseq.c
	int32_t local_table_size = iseq->body->local_table_size;
	int32_t op = slot_idx - VM_ENV_DATA_SIZE;
	int32_t local_idx = local_idx = local_table_size - op - 1;
	RUBY_ASSERT(local_idx >= 0 && local_idx < local_table_size);
	return (uint32_t)local_idx;
	}

	static codegen_status_t
	gen_getlocal_wc0(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Compute the offset from BP to the local
	int32_t slot_idx = (int32_t)jit_get_arg(jit, 0);
	const int32_t offs = -(SIZEOF_VALUE * slot_idx);
	uint32_t local_idx = slot_to_local_idx(jit->iseq, slot_idx);

	// Load environment pointer EP (level 0) from CFP
	gen_get_ep(cb, REG0, 0);

	// Load the local from the EP
	mov(cb, REG0, mem_opnd(64, REG0, offs));

	// Write the local at SP
	x86opnd_t stack_top = ctx_stack_push_local(ctx, local_idx);
	mov(cb, stack_top, REG0);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_getlocal_generic(ctx_t *ctx, uint32_t local_idx, uint32_t level)
	{
	gen_get_ep(cb, REG0, level);

	// Load the local from the block
	// val = *(vm_get_ep(GET_EP(), level) - idx);
	const int32_t offs = -(SIZEOF_VALUE * local_idx);
	mov(cb, REG0, mem_opnd(64, REG0, offs));

	// Write the local at SP
	x86opnd_t stack_top = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, stack_top, REG0);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_getlocal(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	int32_t idx = (int32_t)jit_get_arg(jit, 0);
	int32_t level = (int32_t)jit_get_arg(jit, 1);
	return gen_getlocal_generic(ctx, idx, level);
	}

	static codegen_status_t
	gen_getlocal_wc1(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	int32_t idx = (int32_t)jit_get_arg(jit, 0);
	return gen_getlocal_generic(ctx, idx, 1);
	}

	static codegen_status_t
	gen_setlocal_wc0(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	/*
	vm_env_write(const VALUE *ep, int index, VALUE v)
	{
	VALUE flags = ep[VM_ENV_DATA_INDEX_FLAGS];
	if (LIKELY((flags & VM_ENV_FLAG_WB_REQUIRED) == 0)) {
	VM_STACK_ENV_WRITE(ep, index, v);
	}
	else {
	vm_env_write_slowpath(ep, index, v);
	}
	}
	*/

	int32_t slot_idx = (int32_t)jit_get_arg(jit, 0);
	uint32_t local_idx = slot_to_local_idx(jit->iseq, slot_idx);

	// Load environment pointer EP (level 0) from CFP
	gen_get_ep(cb, REG0, 0);

	// flags & VM_ENV_FLAG_WB_REQUIRED
	x86opnd_t flags_opnd = mem_opnd(64, REG0, sizeof(VALUE) * VM_ENV_DATA_INDEX_FLAGS);
	test(cb, flags_opnd, imm_opnd(VM_ENV_FLAG_WB_REQUIRED));

	// Create a size-exit to fall back to the interpreter
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	// if (flags & VM_ENV_FLAG_WB_REQUIRED) != 0
	jnz_ptr(cb, side_exit);

	// Set the type of the local variable in the context
	val_type_t temp_type = ctx_get_opnd_type(ctx, OPND_STACK(0));
	ctx_set_local_type(ctx, local_idx, temp_type);

	// Pop the value to write from the stack
	x86opnd_t stack_top = ctx_stack_pop(ctx, 1);
	mov(cb, REG1, stack_top);

	// Write the value at the environment pointer
	const int32_t offs = -8 * slot_idx;
	mov(cb, mem_opnd(64, REG0, offs), REG1);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_setlocal_generic(jitstate_t jit, ctx_t ctx, uint32_t local_idx, uint32_t level)
	{
	// Load environment pointer EP at level
	gen_get_ep(cb, REG0, level);

	// flags & VM_ENV_FLAG_WB_REQUIRED
	x86opnd_t flags_opnd = mem_opnd(64, REG0, sizeof(VALUE) * VM_ENV_DATA_INDEX_FLAGS);
	test(cb, flags_opnd, imm_opnd(VM_ENV_FLAG_WB_REQUIRED));

	// Create a size-exit to fall back to the interpreter
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	// if (flags & VM_ENV_FLAG_WB_REQUIRED) != 0
	jnz_ptr(cb, side_exit);

	// Pop the value to write from the stack
	x86opnd_t stack_top = ctx_stack_pop(ctx, 1);
	mov(cb, REG1, stack_top);

	// Write the value at the environment pointer
	const int32_t offs = -(SIZEOF_VALUE * local_idx);
	mov(cb, mem_opnd(64, REG0, offs), REG1);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_setlocal(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	int32_t idx = (int32_t)jit_get_arg(jit, 0);
	int32_t level = (int32_t)jit_get_arg(jit, 1);
	return gen_setlocal_generic(jit, ctx, idx, level);
	}

	static codegen_status_t
	gen_setlocal_wc1(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	int32_t idx = (int32_t)jit_get_arg(jit, 0);
	return gen_setlocal_generic(jit, ctx, idx, 1);
	}

	// Check that `self` is a pointer to an object on the GC heap
	static void
	guard_self_is_heap(codeblock_t cb, x86opnd_t self_opnd, uint8_t side_exit, ctx_t *ctx)
	{

	// `self` is constant throughout the entire region, so we only need to do this check once.
	if (!ctx->self_type.is_heap) {
	ADD_COMMENT(cb, "guard self is heap");
	RUBY_ASSERT(Qfalse < Qnil);
	test(cb, self_opnd, imm_opnd(RUBY_IMMEDIATE_MASK));
	jnz_ptr(cb, side_exit);
	cmp(cb, self_opnd, imm_opnd(Qnil));
	jbe_ptr(cb, side_exit);

	ctx->self_type.is_heap = 1;
	}
	}

	static void
	gen_jnz_to_target0(codeblock_t cb, uint8_t target0, uint8_t *target1, uint8_t shape)
	{
	switch (shape) {
	case SHAPE_NEXT0:
	case SHAPE_NEXT1:
	RUBY_ASSERT(false);
	break;

	case SHAPE_DEFAULT:
	jnz_ptr(cb, target0);
	break;
	}
	}

	static void
	gen_jz_to_target0(codeblock_t cb, uint8_t target0, uint8_t *target1, uint8_t shape)
	{
	switch (shape) {
	case SHAPE_NEXT0:
	case SHAPE_NEXT1:
	RUBY_ASSERT(false);
	break;

	case SHAPE_DEFAULT:
	jz_ptr(cb, target0);
	break;
	}
	}

	static void
	gen_jbe_to_target0(codeblock_t cb, uint8_t target0, uint8_t *target1, uint8_t shape)
	{
	switch (shape) {
	case SHAPE_NEXT0:
	case SHAPE_NEXT1:
	RUBY_ASSERT(false);
	break;

	case SHAPE_DEFAULT:
	jbe_ptr(cb, target0);
	break;
	}
	}

	enum jcc_kinds {
	JCC_JNE,
	JCC_JNZ,
	JCC_JZ,
	JCC_JE,
	JCC_JBE,
	JCC_JNA,
	};

	// Generate a jump to a stub that recompiles the current YARV instruction on failure.
	// When depth_limitk is exceeded, generate a jump to a side exit.
	static void
	jit_chain_guard(enum jcc_kinds jcc, jitstate_t jit, const ctx_t ctx, uint8_t depth_limit, uint8_t *side_exit)
	{
	branchgen_fn target0_gen_fn;

	switch (jcc) {
	case JCC_JNE:
	case JCC_JNZ:
	target0_gen_fn = gen_jnz_to_target0;
	break;
	case JCC_JZ:
	case JCC_JE:
	target0_gen_fn = gen_jz_to_target0;
	break;
	case JCC_JBE:
	case JCC_JNA:
	target0_gen_fn = gen_jbe_to_target0;
	break;
	default:
	rb_bug("yjit: unimplemented jump kind");
	break;
	};

	if (ctx->chain_depth < depth_limit) {
	ctx_t deeper = *ctx;
	deeper.chain_depth++;

	gen_branch(
	jit,
	ctx,
	(blockid_t) { jit->iseq, jit->insn_idx },
	&deeper,
	BLOCKID_NULL,
	NULL,
	target0_gen_fn
	);
	}
	else {
	target0_gen_fn(cb, side_exit, NULL, SHAPE_DEFAULT);
	}
	}

	enum {
	GETIVAR_MAX_DEPTH = 10, // up to 5 different classes, and embedded or not for each
	OPT_AREF_MAX_CHAIN_DEPTH = 2, // hashes and arrays
	SEND_MAX_DEPTH = 5, // up to 5 different classes
	};

	VALUE rb_vm_set_ivar_idx(VALUE obj, uint32_t idx, VALUE val);

	// Codegen for setting an instance variable.
	// Preconditions:
	// - receiver is in REG0
	// - receiver has the same class as CLASS_OF(comptime_receiver)
	// - no stack push or pops to ctx since the entry to the codegen of the instruction being compiled
	static codegen_status_t
	gen_set_ivar(jitstate_t jit, ctx_t ctx, VALUE recv, VALUE klass, ID ivar_name)
	{
	// Save the PC and SP because the callee may allocate
	// Note that this modifies REG_SP, which is why we do it first
	jit_prepare_routine_call(jit, ctx, REG0);

	// Get the operands from the stack
	x86opnd_t val_opnd = ctx_stack_pop(ctx, 1);
	x86opnd_t recv_opnd = ctx_stack_pop(ctx, 1);

	uint32_t ivar_index = rb_obj_ensure_iv_index_mapping(recv, ivar_name);

	// Call rb_vm_set_ivar_idx with the receiver, the index of the ivar, and the value
	mov(cb, C_ARG_REGS[0], recv_opnd);
	mov(cb, C_ARG_REGS[1], imm_opnd(ivar_index));
	mov(cb, C_ARG_REGS[2], val_opnd);
	call_ptr(cb, REG0, (void *)rb_vm_set_ivar_idx);

	x86opnd_t out_opnd = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, out_opnd, RAX);

	return YJIT_KEEP_COMPILING;
	}

	// Codegen for getting an instance variable.
	// Preconditions:
	// - receiver is in REG0
	// - receiver has the same class as CLASS_OF(comptime_receiver)
	// - no stack push or pops to ctx since the entry to the codegen of the instruction being compiled
	static codegen_status_t
	gen_get_ivar(jitstate_t jit, ctx_t ctx, const int max_chain_depth, VALUE comptime_receiver, ID ivar_name, insn_opnd_t reg0_opnd, uint8_t *side_exit)
	{
	VALUE comptime_val_klass = CLASS_OF(comptime_receiver);
	const ctx_t starting_context = *ctx; // make a copy for use with jit_chain_guard

	// If the class uses the default allocator, instances should all be T_OBJECT
	// NOTE: This assumes nobody changes the allocator of the class after allocation.
	// Eventually, we can encode whether an object is T_OBJECT or not
	// inside object shapes.
	if (!RB_TYPE_P(comptime_receiver, T_OBJECT) \|\|
	rb_get_alloc_func(comptime_val_klass) != rb_class_allocate_instance) {
	// General case. Call rb_ivar_get().
	// VALUE rb_ivar_get(VALUE obj, ID id)
	ADD_COMMENT(cb, "call rb_ivar_get()");

	// The function could raise exceptions.
	jit_prepare_routine_call(jit, ctx, REG1);

	mov(cb, C_ARG_REGS[0], REG0);
	mov(cb, C_ARG_REGS[1], imm_opnd((int64_t)ivar_name));
	call_ptr(cb, REG1, (void *)rb_ivar_get);

	if (!reg0_opnd.is_self) {
	(void)ctx_stack_pop(ctx, 1);
	}
	// Push the ivar on the stack
	x86opnd_t out_opnd = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, out_opnd, RAX);

	// Jump to next instruction. This allows guard chains to share the same successor.
	jit_jump_to_next_insn(jit, ctx);
	return YJIT_END_BLOCK;
	}

	/*
	// FIXME:
	// This check was added because of a failure in a test involving the
	// Nokogiri Document class where we see a T_DATA that still has the default
	// allocator.
	// Aaron Patterson argues that this is a bug in the C extension, because
	// people could call .allocate() on the class and still get a T_OBJECT
	// For now I added an extra dynamic check that the receiver is T_OBJECT
	// so we can safely pass all the tests in Shopify Core.
	//
	// Guard that the receiver is T_OBJECT
	// #define RB_BUILTIN_TYPE(x) (int)(((struct RBasic*)(x))->flags & RUBY_T_MASK)
	ADD_COMMENT(cb, "guard receiver is T_OBJECT");
	mov(cb, REG1, member_opnd(REG0, struct RBasic, flags));
	and(cb, REG1, imm_opnd(RUBY_T_MASK));
	cmp(cb, REG1, imm_opnd(T_OBJECT));
	jit_chain_guard(JCC_JNE, jit, &starting_context, max_chain_depth, side_exit);
	*/

	// FIXME: Mapping the index could fail when there is too many ivar names. If we're
	// compiling for a branch stub that can cause the exception to be thrown from the
	// wrong PC.
	uint32_t ivar_index = rb_obj_ensure_iv_index_mapping(comptime_receiver, ivar_name);

	// Pop receiver if it's on the temp stack
	if (!reg0_opnd.is_self) {
	(void)ctx_stack_pop(ctx, 1);
	}

	// Compile time self is embedded and the ivar index lands within the object
	if (RB_FL_TEST_RAW(comptime_receiver, ROBJECT_EMBED) && ivar_index < ROBJECT_EMBED_LEN_MAX) {
	// See ROBJECT_IVPTR() from include/ruby/internal/core/robject.h

	// Guard that self is embedded
	// TODO: BT and JC is shorter
	ADD_COMMENT(cb, "guard embedded getivar");
	x86opnd_t flags_opnd = member_opnd(REG0, struct RBasic, flags);
	test(cb, flags_opnd, imm_opnd(ROBJECT_EMBED));
	jit_chain_guard(JCC_JZ, jit, &starting_context, max_chain_depth, side_exit);

	// Load the variable
	x86opnd_t ivar_opnd = mem_opnd(64, REG0, offsetof(struct RObject, as.ary) + ivar_index * SIZEOF_VALUE);
	mov(cb, REG1, ivar_opnd);

	// Guard that the variable is not Qundef
	cmp(cb, REG1, imm_opnd(Qundef));
	mov(cb, REG0, imm_opnd(Qnil));
	cmove(cb, REG1, REG0);

	// Push the ivar on the stack
	x86opnd_t out_opnd = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, out_opnd, REG1);
	}
	else {
	// Compile time value is not embeded.

	// Guard that value is not embedded
	// See ROBJECT_IVPTR() from include/ruby/internal/core/robject.h
	ADD_COMMENT(cb, "guard extended getivar");
	x86opnd_t flags_opnd = member_opnd(REG0, struct RBasic, flags);
	test(cb, flags_opnd, imm_opnd(ROBJECT_EMBED));
	jit_chain_guard(JCC_JNZ, jit, &starting_context, max_chain_depth, side_exit);

	// check that the extended table is big enough
	if (ivar_index >= ROBJECT_EMBED_LEN_MAX + 1) {
	// Check that the slot is inside the extended table (num_slots > index)
	x86opnd_t num_slots = mem_opnd(32, REG0, offsetof(struct RObject, as.heap.numiv));
	cmp(cb, num_slots, imm_opnd(ivar_index));
	jle_ptr(cb, COUNTED_EXIT(side_exit, getivar_idx_out_of_range));
	}

	// Get a pointer to the extended table
	x86opnd_t tbl_opnd = mem_opnd(64, REG0, offsetof(struct RObject, as.heap.ivptr));
	mov(cb, REG0, tbl_opnd);

	// Read the ivar from the extended table
	x86opnd_t ivar_opnd = mem_opnd(64, REG0, sizeof(VALUE) * ivar_index);
	mov(cb, REG0, ivar_opnd);

	// Check that the ivar is not Qundef
	cmp(cb, REG0, imm_opnd(Qundef));
	mov(cb, REG1, imm_opnd(Qnil));
	cmove(cb, REG0, REG1);

	// Push the ivar on the stack
	x86opnd_t out_opnd = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, out_opnd, REG0);
	}

	// Jump to next instruction. This allows guard chains to share the same successor.
	jit_jump_to_next_insn(jit, ctx);
	return YJIT_END_BLOCK;
	}

	static codegen_status_t
	gen_getinstancevariable(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Defer compilation so we can specialize on a runtime `self`
	if (!jit_at_current_insn(jit)) {
	defer_compilation(jit, ctx);
	return YJIT_END_BLOCK;
	}

	ID ivar_name = (ID)jit_get_arg(jit, 0);

	VALUE comptime_val = jit_peek_at_self(jit, ctx);
	VALUE comptime_val_klass = CLASS_OF(comptime_val);

	// Generate a side exit
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	// Guard that the receiver has the same class as the one from compile time.
	mov(cb, REG0, member_opnd(REG_CFP, rb_control_frame_t, self));
	guard_self_is_heap(cb, REG0, COUNTED_EXIT(side_exit, getivar_se_self_not_heap), ctx);

	jit_guard_known_klass(jit, ctx, comptime_val_klass, OPND_SELF, comptime_val, GETIVAR_MAX_DEPTH, side_exit);

	return gen_get_ivar(jit, ctx, GETIVAR_MAX_DEPTH, comptime_val, ivar_name, OPND_SELF, side_exit);
	}

	void rb_vm_setinstancevariable(const rb_iseq_t *iseq, VALUE obj, ID id, VALUE val, IVC ic);

	static codegen_status_t
	gen_setinstancevariable(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	ID id = (ID)jit_get_arg(jit, 0);
	IVC ic = (IVC)jit_get_arg(jit, 1);

	// Save the PC and SP because the callee may allocate
	// Note that this modifies REG_SP, which is why we do it first
	jit_prepare_routine_call(jit, ctx, REG0);

	// Get the operands from the stack
	x86opnd_t val_opnd = ctx_stack_pop(ctx, 1);

	// Call rb_vm_setinstancevariable(iseq, obj, id, val, ic);
	mov(cb, C_ARG_REGS[1], member_opnd(REG_CFP, rb_control_frame_t, self));
	mov(cb, C_ARG_REGS[3], val_opnd);
	mov(cb, C_ARG_REGS[2], imm_opnd(id));
	mov(cb, C_ARG_REGS[4], const_ptr_opnd(ic));
	jit_mov_gc_ptr(jit, cb, C_ARG_REGS[0], (VALUE)jit->iseq);
	call_ptr(cb, REG0, (void *)rb_vm_setinstancevariable);

	return YJIT_KEEP_COMPILING;
	}

	bool rb_vm_defined(rb_execution_context_t ec, rb_control_frame_t reg_cfp, rb_num_t op_type, VALUE obj, VALUE v);

	static codegen_status_t
	gen_defined(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	rb_num_t op_type = (rb_num_t)jit_get_arg(jit, 0);
	VALUE obj = (VALUE)jit_get_arg(jit, 1);
	VALUE pushval = (VALUE)jit_get_arg(jit, 2);

	// Save the PC and SP because the callee may allocate
	// Note that this modifies REG_SP, which is why we do it first
	jit_prepare_routine_call(jit, ctx, REG0);

	// Get the operands from the stack
	x86opnd_t v_opnd = ctx_stack_pop(ctx, 1);

	// Call vm_defined(ec, reg_cfp, op_type, obj, v)
	mov(cb, C_ARG_REGS[0], REG_EC);
	mov(cb, C_ARG_REGS[1], REG_CFP);
	mov(cb, C_ARG_REGS[2], imm_opnd(op_type));
	jit_mov_gc_ptr(jit, cb, C_ARG_REGS[3], (VALUE)obj);
	mov(cb, C_ARG_REGS[4], v_opnd);
	call_ptr(cb, REG0, (void *)rb_vm_defined);

	// if (vm_defined(ec, GET_CFP(), op_type, obj, v)) {
	// val = pushval;
	// }
	jit_mov_gc_ptr(jit, cb, REG1, (VALUE)pushval);
	cmp(cb, AL, imm_opnd(0));
	mov(cb, RAX, imm_opnd(Qnil));
	cmovnz(cb, RAX, REG1);

	// Push the return value onto the stack
	val_type_t out_type = SPECIAL_CONST_P(pushval)? TYPE_IMM:TYPE_UNKNOWN;
	x86opnd_t stack_ret = ctx_stack_push(ctx, out_type);
	mov(cb, stack_ret, RAX);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_checktype(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	enum ruby_value_type type_val = (enum ruby_value_type)jit_get_arg(jit, 0);
	// Only three types are emitted by compile.c
	if (type_val == T_STRING \|\| type_val == T_ARRAY \|\| type_val == T_HASH) {
	val_type_t val_type = ctx_get_opnd_type(ctx, OPND_STACK(0));
	x86opnd_t val = ctx_stack_pop(ctx, 1);

	x86opnd_t stack_ret;

	// Check if we know from type information
	if ((type_val == T_STRING && val_type.type == ETYPE_STRING) \|\|
	(type_val == T_ARRAY && val_type.type == ETYPE_ARRAY) \|\|
	(type_val == T_HASH && val_type.type == ETYPE_HASH)) {
	// guaranteed type match
	stack_ret = ctx_stack_push(ctx, TYPE_TRUE);
	mov(cb, stack_ret, imm_opnd(Qtrue));
	return YJIT_KEEP_COMPILING;
	}
	else if (val_type.is_imm \|\| val_type.type != ETYPE_UNKNOWN) {
	// guaranteed not to match T_STRING/T_ARRAY/T_HASH
	stack_ret = ctx_stack_push(ctx, TYPE_FALSE);
	mov(cb, stack_ret, imm_opnd(Qfalse));
	return YJIT_KEEP_COMPILING;
	}

	mov(cb, REG0, val);
	mov(cb, REG1, imm_opnd(Qfalse));

	uint32_t ret = cb_new_label(cb, "ret");

	if (!val_type.is_heap) {
	// if (SPECIAL_CONST_P(val)) {
	// Return Qfalse via REG1 if not on heap
	test(cb, REG0, imm_opnd(RUBY_IMMEDIATE_MASK));
	jnz_label(cb, ret);
	cmp(cb, REG0, imm_opnd(Qnil));
	jbe_label(cb, ret);
	}

	// Check type on object
	mov(cb, REG0, mem_opnd(64, REG0, offsetof(struct RBasic, flags)));
	and(cb, REG0, imm_opnd(RUBY_T_MASK));
	cmp(cb, REG0, imm_opnd(type_val));
	mov(cb, REG0, imm_opnd(Qtrue));
	// REG1 contains Qfalse from above
	cmove(cb, REG1, REG0);

	cb_write_label(cb, ret);
	stack_ret = ctx_stack_push(ctx, TYPE_IMM);
	mov(cb, stack_ret, REG1);
	cb_link_labels(cb);

	return YJIT_KEEP_COMPILING;
	}
	else {
	return YJIT_CANT_COMPILE;
	}
	}

	static codegen_status_t
	gen_concatstrings(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	rb_num_t n = (rb_num_t)jit_get_arg(jit, 0);

	// Save the PC and SP because we are allocating
	jit_prepare_routine_call(jit, ctx, REG0);

	x86opnd_t values_ptr = ctx_sp_opnd(ctx, -(sizeof(VALUE) * (uint32_t)n));

	// call rb_str_concat_literals(long n, const VALUE *strings);
	mov(cb, C_ARG_REGS[0], imm_opnd(n));
	lea(cb, C_ARG_REGS[1], values_ptr);
	call_ptr(cb, REG0, (void *)rb_str_concat_literals);

	ctx_stack_pop(ctx, n);
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_STRING);
	mov(cb, stack_ret, RAX);

	return YJIT_KEEP_COMPILING;
	}

	static void
	guard_two_fixnums(ctx_t ctx, uint8_t side_exit)
	{
	// Get the stack operand types
	val_type_t arg1_type = ctx_get_opnd_type(ctx, OPND_STACK(0));
	val_type_t arg0_type = ctx_get_opnd_type(ctx, OPND_STACK(1));

	if (arg0_type.is_heap \|\| arg1_type.is_heap) {
	jmp_ptr(cb, side_exit);
	return;
	}

	if (arg0_type.type != ETYPE_FIXNUM && arg0_type.type != ETYPE_UNKNOWN) {
	jmp_ptr(cb, side_exit);
	return;
	}

	if (arg1_type.type != ETYPE_FIXNUM && arg1_type.type != ETYPE_UNKNOWN) {
	jmp_ptr(cb, side_exit);
	return;
	}

	RUBY_ASSERT(!arg0_type.is_heap);
	RUBY_ASSERT(!arg1_type.is_heap);
	RUBY_ASSERT(arg0_type.type == ETYPE_FIXNUM \|\| arg0_type.type == ETYPE_UNKNOWN);
	RUBY_ASSERT(arg1_type.type == ETYPE_FIXNUM \|\| arg1_type.type == ETYPE_UNKNOWN);

	// Get stack operands without popping them
	x86opnd_t arg1 = ctx_stack_opnd(ctx, 0);
	x86opnd_t arg0 = ctx_stack_opnd(ctx, 1);

	// If not fixnums, fall back
	if (arg0_type.type != ETYPE_FIXNUM) {
	ADD_COMMENT(cb, "guard arg0 fixnum");
	test(cb, arg0, imm_opnd(RUBY_FIXNUM_FLAG));
	jz_ptr(cb, side_exit);
	}
	if (arg1_type.type != ETYPE_FIXNUM) {
	ADD_COMMENT(cb, "guard arg1 fixnum");
	test(cb, arg1, imm_opnd(RUBY_FIXNUM_FLAG));
	jz_ptr(cb, side_exit);
	}

	// Set stack types in context
	ctx_upgrade_opnd_type(ctx, OPND_STACK(0), TYPE_FIXNUM);
	ctx_upgrade_opnd_type(ctx, OPND_STACK(1), TYPE_FIXNUM);
	}

	// Conditional move operation used by comparison operators
	typedef void (cmov_fn)(codeblock_t cb, x86opnd_t opnd0, x86opnd_t opnd1);

	static codegen_status_t
	gen_fixnum_cmp(jitstate_t jit, ctx_t ctx, cmov_fn cmov_op)
	{
	// Defer compilation so we can specialize base on a runtime receiver
	if (!jit_at_current_insn(jit)) {
	defer_compilation(jit, ctx);
	return YJIT_END_BLOCK;
	}

	VALUE comptime_a = jit_peek_at_stack(jit, ctx, 1);
	VALUE comptime_b = jit_peek_at_stack(jit, ctx, 0);

	if (FIXNUM_P(comptime_a) && FIXNUM_P(comptime_b)) {
	// Create a size-exit to fall back to the interpreter
	// Note: we generate the side-exit before popping operands from the stack
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	if (!assume_bop_not_redefined(jit->block, INTEGER_REDEFINED_OP_FLAG, BOP_LT)) {
	return YJIT_CANT_COMPILE;
	}

	// Check that both operands are fixnums
	guard_two_fixnums(ctx, side_exit);

	// Get the operands from the stack
	x86opnd_t arg1 = ctx_stack_pop(ctx, 1);
	x86opnd_t arg0 = ctx_stack_pop(ctx, 1);

	// Compare the arguments
	xor(cb, REG0_32, REG0_32); // REG0 = Qfalse
	mov(cb, REG1, arg0);
	cmp(cb, REG1, arg1);
	mov(cb, REG1, imm_opnd(Qtrue));
	cmov_op(cb, REG0, REG1);

	// Push the output on the stack
	x86opnd_t dst = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, dst, REG0);

	return YJIT_KEEP_COMPILING;
	}
	else {
	return gen_opt_send_without_block(jit, ctx, cb);
	}
	}

	static codegen_status_t
	gen_opt_lt(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	return gen_fixnum_cmp(jit, ctx, cmovl);
	}

	static codegen_status_t
	gen_opt_le(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	return gen_fixnum_cmp(jit, ctx, cmovle);
	}

	static codegen_status_t
	gen_opt_ge(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	return gen_fixnum_cmp(jit, ctx, cmovge);
	}

	static codegen_status_t
	gen_opt_gt(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	return gen_fixnum_cmp(jit, ctx, cmovg);
	}

	// Implements specialized equality for either two fixnum or two strings
	// Returns true if code was generated, otherwise false
	static bool
	gen_equality_specialized(jitstate_t jit, ctx_t ctx, uint8_t *side_exit)
	{
	VALUE comptime_a = jit_peek_at_stack(jit, ctx, 1);
	VALUE comptime_b = jit_peek_at_stack(jit, ctx, 0);

	x86opnd_t a_opnd = ctx_stack_opnd(ctx, 1);
	x86opnd_t b_opnd = ctx_stack_opnd(ctx, 0);

	if (FIXNUM_P(comptime_a) && FIXNUM_P(comptime_b)) {
	if (!assume_bop_not_redefined(jit->block, INTEGER_REDEFINED_OP_FLAG, BOP_EQ)) {
	// if overridden, emit the generic version
	return false;
	}

	guard_two_fixnums(ctx, side_exit);

	mov(cb, REG0, a_opnd);
	cmp(cb, REG0, b_opnd);

	mov(cb, REG0, imm_opnd(Qfalse));
	mov(cb, REG1, imm_opnd(Qtrue));
	cmove(cb, REG0, REG1);

	// Push the output on the stack
	ctx_stack_pop(ctx, 2);
	x86opnd_t dst = ctx_stack_push(ctx, TYPE_IMM);
	mov(cb, dst, REG0);

	return true;
	}
	else if (CLASS_OF(comptime_a) == rb_cString &&
	CLASS_OF(comptime_b) == rb_cString) {
	if (!assume_bop_not_redefined(jit->block, STRING_REDEFINED_OP_FLAG, BOP_EQ)) {
	// if overridden, emit the generic version
	return false;
	}

	// Load a and b in preparation for call later
	mov(cb, C_ARG_REGS[0], a_opnd);
	mov(cb, C_ARG_REGS[1], b_opnd);

	// Guard that a is a String
	mov(cb, REG0, C_ARG_REGS[0]);
	jit_guard_known_klass(jit, ctx, rb_cString, OPND_STACK(1), comptime_a, SEND_MAX_DEPTH, side_exit);

	uint32_t ret = cb_new_label(cb, "ret");

	// If they are equal by identity, return true
	cmp(cb, C_ARG_REGS[0], C_ARG_REGS[1]);
	mov(cb, RAX, imm_opnd(Qtrue));
	je_label(cb, ret);

	// Otherwise guard that b is a T_STRING (from type info) or String (from runtime guard)
	if (ctx_get_opnd_type(ctx, OPND_STACK(0)).type != ETYPE_STRING) {
	mov(cb, REG0, C_ARG_REGS[1]);
	// Note: any T_STRING is valid here, but we check for a ::String for simplicity
	jit_guard_known_klass(jit, ctx, rb_cString, OPND_STACK(0), comptime_b, SEND_MAX_DEPTH, side_exit);
	}

	// Call rb_str_eql_internal(a, b)
	call_ptr(cb, REG0, (void *)rb_str_eql_internal);

	// Push the output on the stack
	cb_write_label(cb, ret);
	ctx_stack_pop(ctx, 2);
	x86opnd_t dst = ctx_stack_push(ctx, TYPE_IMM);
	mov(cb, dst, RAX);
	cb_link_labels(cb);

	return true;
	}
	else {
	return false;
	}
	}

	static codegen_status_t
	gen_opt_eq(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Defer compilation so we can specialize base on a runtime receiver
	if (!jit_at_current_insn(jit)) {
	defer_compilation(jit, ctx);
	return YJIT_END_BLOCK;
	}

	// Create a size-exit to fall back to the interpreter
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	if (gen_equality_specialized(jit, ctx, side_exit)) {
	jit_jump_to_next_insn(jit, ctx);
	return YJIT_END_BLOCK;
	}
	else {
	return gen_opt_send_without_block(jit, ctx, cb);
	}
	}

	static codegen_status_t gen_send_general(jitstate_t jit, ctx_t ctx, struct rb_call_data cd, rb_iseq_t block);

	static codegen_status_t
	gen_opt_neq(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// opt_neq is passed two rb_call_data as arguments:
	// first for ==, second for !=
	struct rb_call_data cd = (struct rb_call_data )jit_get_arg(jit, 1);
	return gen_send_general(jit, ctx, cd, NULL);
	}

	static codegen_status_t
	gen_opt_aref(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	struct rb_call_data * cd = (struct rb_call_data *)jit_get_arg(jit, 0);
	int32_t argc = (int32_t)vm_ci_argc(cd->ci);

	// Only JIT one arg calls like `ary[6]`
	if (argc != 1) {
	GEN_COUNTER_INC(cb, oaref_argc_not_one);
	return YJIT_CANT_COMPILE;
	}

	// Defer compilation so we can specialize base on a runtime receiver
	if (!jit_at_current_insn(jit)) {
	defer_compilation(jit, ctx);
	return YJIT_END_BLOCK;
	}

	// Remember the context on entry for adding guard chains
	const ctx_t starting_context = *ctx;

	// Specialize base on compile time values
	VALUE comptime_idx = jit_peek_at_stack(jit, ctx, 0);
	VALUE comptime_recv = jit_peek_at_stack(jit, ctx, 1);

	// Create a size-exit to fall back to the interpreter
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	if (CLASS_OF(comptime_recv) == rb_cArray && RB_FIXNUM_P(comptime_idx)) {
	if (!assume_bop_not_redefined(jit->block, ARRAY_REDEFINED_OP_FLAG, BOP_AREF)) {
	return YJIT_CANT_COMPILE;
	}

	// Pop the stack operands
	x86opnd_t idx_opnd = ctx_stack_pop(ctx, 1);
	x86opnd_t recv_opnd = ctx_stack_pop(ctx, 1);
	mov(cb, REG0, recv_opnd);

	// if (SPECIAL_CONST_P(recv)) {
	// Bail if receiver is not a heap object
	test(cb, REG0, imm_opnd(RUBY_IMMEDIATE_MASK));
	jnz_ptr(cb, side_exit);
	cmp(cb, REG0, imm_opnd(Qfalse));
	je_ptr(cb, side_exit);
	cmp(cb, REG0, imm_opnd(Qnil));
	je_ptr(cb, side_exit);

	// Bail if recv has a class other than ::Array.
	// BOP_AREF check above is only good for ::Array.
	mov(cb, REG1, mem_opnd(64, REG0, offsetof(struct RBasic, klass)));
	mov(cb, REG0, const_ptr_opnd((void *)rb_cArray));
	cmp(cb, REG0, REG1);
	jit_chain_guard(JCC_JNE, jit, &starting_context, OPT_AREF_MAX_CHAIN_DEPTH, side_exit);

	// Bail if idx is not a FIXNUM
	mov(cb, REG1, idx_opnd);
	test(cb, REG1, imm_opnd(RUBY_FIXNUM_FLAG));
	jz_ptr(cb, COUNTED_EXIT(side_exit, oaref_arg_not_fixnum));

	// Call VALUE rb_ary_entry_internal(VALUE ary, long offset).
	// It never raises or allocates, so we don't need to write to cfp->pc.
	{
	mov(cb, RDI, recv_opnd);
	sar(cb, REG1, imm_opnd(1)); // Convert fixnum to int
	mov(cb, RSI, REG1);
	call_ptr(cb, REG0, (void *)rb_ary_entry_internal);

	// Push the return value onto the stack
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, stack_ret, RAX);
	}

	// Jump to next instruction. This allows guard chains to share the same successor.
	jit_jump_to_next_insn(jit, ctx);
	return YJIT_END_BLOCK;
	}
	else if (CLASS_OF(comptime_recv) == rb_cHash) {
	if (!assume_bop_not_redefined(jit->block, HASH_REDEFINED_OP_FLAG, BOP_AREF)) {
	return YJIT_CANT_COMPILE;
	}

	x86opnd_t key_opnd = ctx_stack_opnd(ctx, 0);
	x86opnd_t recv_opnd = ctx_stack_opnd(ctx, 1);

	// Guard that the receiver is a hash
	mov(cb, REG0, recv_opnd);
	jit_guard_known_klass(jit, ctx, rb_cHash, OPND_STACK(1), comptime_recv, OPT_AREF_MAX_CHAIN_DEPTH, side_exit);

	// Setup arguments for rb_hash_aref().
	mov(cb, C_ARG_REGS[0], REG0);
	mov(cb, C_ARG_REGS[1], key_opnd);

	// Prepare to call rb_hash_aref(). It might call #hash on the key.
	jit_prepare_routine_call(jit, ctx, REG0);

	call_ptr(cb, REG0, (void *)rb_hash_aref);

	// Pop the key and the reciever
	(void)ctx_stack_pop(ctx, 2);

	// Push the return value onto the stack
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, stack_ret, RAX);

	// Jump to next instruction. This allows guard chains to share the same successor.
	jit_jump_to_next_insn(jit, ctx);
	return YJIT_END_BLOCK;
	}
	else {
	// General case. Call the [] method.
	return gen_opt_send_without_block(jit, ctx, cb);
	}
	}

	static codegen_status_t
	gen_opt_aset(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Defer compilation so we can specialize on a runtime `self`
	if (!jit_at_current_insn(jit)) {
	defer_compilation(jit, ctx);
	return YJIT_END_BLOCK;
	}

	VALUE comptime_recv = jit_peek_at_stack(jit, ctx, 2);
	VALUE comptime_key = jit_peek_at_stack(jit, ctx, 1);

	// Get the operands from the stack
	x86opnd_t recv = ctx_stack_opnd(ctx, 2);
	x86opnd_t key = ctx_stack_opnd(ctx, 1);
	x86opnd_t val = ctx_stack_opnd(ctx, 0);

	if (CLASS_OF(comptime_recv) == rb_cArray && FIXNUM_P(comptime_key)) {
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	// Guard receiver is an Array
	mov(cb, REG0, recv);
	jit_guard_known_klass(jit, ctx, rb_cArray, OPND_STACK(2), comptime_recv, SEND_MAX_DEPTH, side_exit);

	// Guard key is a fixnum
	mov(cb, REG0, key);
	jit_guard_known_klass(jit, ctx, rb_cInteger, OPND_STACK(1), comptime_key, SEND_MAX_DEPTH, side_exit);

	// Call rb_ary_store
	mov(cb, C_ARG_REGS[0], recv);
	mov(cb, C_ARG_REGS[1], key);
	sar(cb, C_ARG_REGS[1], imm_opnd(1)); // FIX2LONG(key)
	mov(cb, C_ARG_REGS[2], val);

	// We might allocate or raise
	jit_prepare_routine_call(jit, ctx, REG0);

	call_ptr(cb, REG0, (void *)rb_ary_store);

	// rb_ary_store returns void
	// stored value should still be on stack
	mov(cb, REG0, ctx_stack_opnd(ctx, 0));

	// Push the return value onto the stack
	ctx_stack_pop(ctx, 3);
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, stack_ret, REG0);

	jit_jump_to_next_insn(jit, ctx);
	return YJIT_END_BLOCK;
	}
	else if (CLASS_OF(comptime_recv) == rb_cHash) {
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	// Guard receiver is a Hash
	mov(cb, REG0, recv);
	jit_guard_known_klass(jit, ctx, rb_cHash, OPND_STACK(2), comptime_recv, SEND_MAX_DEPTH, side_exit);

	// Call rb_hash_aset
	mov(cb, C_ARG_REGS[0], recv);
	mov(cb, C_ARG_REGS[1], key);
	mov(cb, C_ARG_REGS[2], val);

	// We might allocate or raise
	jit_prepare_routine_call(jit, ctx, REG0);

	call_ptr(cb, REG0, (void *)rb_hash_aset);

	// Push the return value onto the stack
	ctx_stack_pop(ctx, 3);
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, stack_ret, RAX);

	jit_jump_to_next_insn(jit, ctx);
	return YJIT_END_BLOCK;
	}
	else {
	return gen_opt_send_without_block(jit, ctx, cb);
	}
	}

	static codegen_status_t
	gen_opt_and(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Defer compilation so we can specialize on a runtime `self`
	if (!jit_at_current_insn(jit)) {
	defer_compilation(jit, ctx);
	return YJIT_END_BLOCK;
	}

	VALUE comptime_a = jit_peek_at_stack(jit, ctx, 1);
	VALUE comptime_b = jit_peek_at_stack(jit, ctx, 0);

	if (FIXNUM_P(comptime_a) && FIXNUM_P(comptime_b)) {
	// Create a size-exit to fall back to the interpreter
	// Note: we generate the side-exit before popping operands from the stack
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	if (!assume_bop_not_redefined(jit->block, INTEGER_REDEFINED_OP_FLAG, BOP_AND)) {
	return YJIT_CANT_COMPILE;
	}

	// Check that both operands are fixnums
	guard_two_fixnums(ctx, side_exit);

	// Get the operands and destination from the stack
	x86opnd_t arg1 = ctx_stack_pop(ctx, 1);
	x86opnd_t arg0 = ctx_stack_pop(ctx, 1);

	// Do the bitwise and arg0 & arg1
	mov(cb, REG0, arg0);
	and(cb, REG0, arg1);

	// Push the output on the stack
	x86opnd_t dst = ctx_stack_push(ctx, TYPE_FIXNUM);
	mov(cb, dst, REG0);

	return YJIT_KEEP_COMPILING;
	}
	else {
	// Delegate to send, call the method on the recv
	return gen_opt_send_without_block(jit, ctx, cb);
	}
	}

	static codegen_status_t
	gen_opt_or(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Defer compilation so we can specialize on a runtime `self`
	if (!jit_at_current_insn(jit)) {
	defer_compilation(jit, ctx);
	return YJIT_END_BLOCK;
	}

	VALUE comptime_a = jit_peek_at_stack(jit, ctx, 1);
	VALUE comptime_b = jit_peek_at_stack(jit, ctx, 0);

	if (FIXNUM_P(comptime_a) && FIXNUM_P(comptime_b)) {
	// Create a size-exit to fall back to the interpreter
	// Note: we generate the side-exit before popping operands from the stack
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	if (!assume_bop_not_redefined(jit->block, INTEGER_REDEFINED_OP_FLAG, BOP_OR)) {
	return YJIT_CANT_COMPILE;
	}

	// Check that both operands are fixnums
	guard_two_fixnums(ctx, side_exit);

	// Get the operands and destination from the stack
	x86opnd_t arg1 = ctx_stack_pop(ctx, 1);
	x86opnd_t arg0 = ctx_stack_pop(ctx, 1);

	// Do the bitwise or arg0 \| arg1
	mov(cb, REG0, arg0);
	or(cb, REG0, arg1);

	// Push the output on the stack
	x86opnd_t dst = ctx_stack_push(ctx, TYPE_FIXNUM);
	mov(cb, dst, REG0);

	return YJIT_KEEP_COMPILING;
	}
	else {
	// Delegate to send, call the method on the recv
	return gen_opt_send_without_block(jit, ctx, cb);
	}
	}

	static codegen_status_t
	gen_opt_minus(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Defer compilation so we can specialize on a runtime `self`
	if (!jit_at_current_insn(jit)) {
	defer_compilation(jit, ctx);
	return YJIT_END_BLOCK;
	}

	VALUE comptime_a = jit_peek_at_stack(jit, ctx, 1);
	VALUE comptime_b = jit_peek_at_stack(jit, ctx, 0);

	if (FIXNUM_P(comptime_a) && FIXNUM_P(comptime_b)) {
	// Create a size-exit to fall back to the interpreter
	// Note: we generate the side-exit before popping operands from the stack
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	if (!assume_bop_not_redefined(jit->block, INTEGER_REDEFINED_OP_FLAG, BOP_MINUS)) {
	return YJIT_CANT_COMPILE;
	}

	// Check that both operands are fixnums
	guard_two_fixnums(ctx, side_exit);

	// Get the operands and destination from the stack
	x86opnd_t arg1 = ctx_stack_pop(ctx, 1);
	x86opnd_t arg0 = ctx_stack_pop(ctx, 1);

	// Subtract arg0 - arg1 and test for overflow
	mov(cb, REG0, arg0);
	sub(cb, REG0, arg1);
	jo_ptr(cb, side_exit);
	add(cb, REG0, imm_opnd(1));

	// Push the output on the stack
	x86opnd_t dst = ctx_stack_push(ctx, TYPE_FIXNUM);
	mov(cb, dst, REG0);

	return YJIT_KEEP_COMPILING;
	}
	else {
	// Delegate to send, call the method on the recv
	return gen_opt_send_without_block(jit, ctx, cb);
	}
	}

	static codegen_status_t
	gen_opt_plus(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Defer compilation so we can specialize on a runtime `self`
	if (!jit_at_current_insn(jit)) {
	defer_compilation(jit, ctx);
	return YJIT_END_BLOCK;
	}

	VALUE comptime_a = jit_peek_at_stack(jit, ctx, 1);
	VALUE comptime_b = jit_peek_at_stack(jit, ctx, 0);

	if (FIXNUM_P(comptime_a) && FIXNUM_P(comptime_b)) {
	// Create a size-exit to fall back to the interpreter
	// Note: we generate the side-exit before popping operands from the stack
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	if (!assume_bop_not_redefined(jit->block, INTEGER_REDEFINED_OP_FLAG, BOP_PLUS)) {
	return YJIT_CANT_COMPILE;
	}

	// Check that both operands are fixnums
	guard_two_fixnums(ctx, side_exit);

	// Get the operands and destination from the stack
	x86opnd_t arg1 = ctx_stack_pop(ctx, 1);
	x86opnd_t arg0 = ctx_stack_pop(ctx, 1);

	// Add arg0 + arg1 and test for overflow
	mov(cb, REG0, arg0);
	sub(cb, REG0, imm_opnd(1));
	add(cb, REG0, arg1);
	jo_ptr(cb, side_exit);

	// Push the output on the stack
	x86opnd_t dst = ctx_stack_push(ctx, TYPE_FIXNUM);
	mov(cb, dst, REG0);

	return YJIT_KEEP_COMPILING;
	}
	else {
	// Delegate to send, call the method on the recv
	return gen_opt_send_without_block(jit, ctx, cb);
	}
	}

	static codegen_status_t
	gen_opt_mult(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Delegate to send, call the method on the recv
	return gen_opt_send_without_block(jit, ctx, cb);
	}

	static codegen_status_t
	gen_opt_div(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Delegate to send, call the method on the recv
	return gen_opt_send_without_block(jit, ctx, cb);
	}

	VALUE rb_vm_opt_mod(VALUE recv, VALUE obj);

	static codegen_status_t
	gen_opt_mod(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Save the PC and SP because the callee may allocate bignums
	// Note that this modifies REG_SP, which is why we do it first
	jit_prepare_routine_call(jit, ctx, REG0);

	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	// Get the operands from the stack
	x86opnd_t arg1 = ctx_stack_pop(ctx, 1);
	x86opnd_t arg0 = ctx_stack_pop(ctx, 1);

	// Call rb_vm_opt_mod(VALUE recv, VALUE obj)
	mov(cb, C_ARG_REGS[0], arg0);
	mov(cb, C_ARG_REGS[1], arg1);
	call_ptr(cb, REG0, (void *)rb_vm_opt_mod);

	// If val == Qundef, bail to do a method call
	cmp(cb, RAX, imm_opnd(Qundef));
	je_ptr(cb, side_exit);

	// Push the return value onto the stack
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, stack_ret, RAX);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_opt_ltlt(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Delegate to send, call the method on the recv
	return gen_opt_send_without_block(jit, ctx, cb);
	}

	static codegen_status_t
	gen_opt_nil_p(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Delegate to send, call the method on the recv
	return gen_opt_send_without_block(jit, ctx, cb);
	}

	static codegen_status_t
	gen_opt_empty_p(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Delegate to send, call the method on the recv
	return gen_opt_send_without_block(jit, ctx, cb);
	}

	static codegen_status_t
	gen_opt_str_freeze(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	if (!assume_bop_not_redefined(jit->block, STRING_REDEFINED_OP_FLAG, BOP_FREEZE)) {
	return YJIT_CANT_COMPILE;
	}

	VALUE str = jit_get_arg(jit, 0);
	jit_mov_gc_ptr(jit, cb, REG0, str);

	// Push the return value onto the stack
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_STRING);
	mov(cb, stack_ret, REG0);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_opt_str_uminus(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	if (!assume_bop_not_redefined(jit->block, STRING_REDEFINED_OP_FLAG, BOP_UMINUS)) {
	return YJIT_CANT_COMPILE;
	}

	VALUE str = jit_get_arg(jit, 0);
	jit_mov_gc_ptr(jit, cb, REG0, str);

	// Push the return value onto the stack
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_STRING);
	mov(cb, stack_ret, REG0);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_opt_not(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	return gen_opt_send_without_block(jit, ctx, cb);
	}

	static codegen_status_t
	gen_opt_size(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	return gen_opt_send_without_block(jit, ctx, cb);
	}

	static codegen_status_t
	gen_opt_length(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	return gen_opt_send_without_block(jit, ctx, cb);
	}

	static codegen_status_t
	gen_opt_regexpmatch2(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	return gen_opt_send_without_block(jit, ctx, cb);
	}

	static codegen_status_t
	gen_opt_case_dispatch(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Normally this instruction would lookup the key in a hash and jump to an
	// offset based on that.
	// Instead we can take the fallback case and continue with the next
	// instruciton.
	// We'd hope that our jitted code will be sufficiently fast without the
	// hash lookup, at least for small hashes, but it's worth revisiting this
	// assumption in the future.

	ctx_stack_pop(ctx, 1);

	return YJIT_KEEP_COMPILING; // continue with the next instruction
	}

	static void
	gen_branchif_branch(codeblock_t cb, uint8_t target0, uint8_t *target1, uint8_t shape)
	{
	switch (shape) {
	case SHAPE_NEXT0:
	jz_ptr(cb, target1);
	break;

	case SHAPE_NEXT1:
	jnz_ptr(cb, target0);
	break;

	case SHAPE_DEFAULT:
	jnz_ptr(cb, target0);
	jmp_ptr(cb, target1);
	break;
	}
	}

	static codegen_status_t
	gen_branchif(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	int32_t jump_offset = (int32_t)jit_get_arg(jit, 0);

	// Check for interrupts, but only on backward branches that may create loops
	if (jump_offset < 0) {
	uint8_t *side_exit = yjit_side_exit(jit, ctx);
	yjit_check_ints(cb, side_exit);
	}

	// Test if any bit (outside of the Qnil bit) is on
	// RUBY_Qfalse /* ...0000 0000 */
	// RUBY_Qnil /* ...0000 1000 */
	x86opnd_t val_opnd = ctx_stack_pop(ctx, 1);
	test(cb, val_opnd, imm_opnd(~Qnil));

	// Get the branch target instruction offsets
	uint32_t next_idx = jit_next_insn_idx(jit);
	uint32_t jump_idx = next_idx + jump_offset;
	blockid_t next_block = { jit->iseq, next_idx };
	blockid_t jump_block = { jit->iseq, jump_idx };

	// Generate the branch instructions
	gen_branch(
	jit,
	ctx,
	jump_block,
	ctx,
	next_block,
	ctx,
	gen_branchif_branch
	);

	return YJIT_END_BLOCK;
	}

	static void
	gen_branchunless_branch(codeblock_t cb, uint8_t target0, uint8_t *target1, uint8_t shape)
	{
	switch (shape) {
	case SHAPE_NEXT0:
	jnz_ptr(cb, target1);
	break;

	case SHAPE_NEXT1:
	jz_ptr(cb, target0);
	break;

	case SHAPE_DEFAULT:
	jz_ptr(cb, target0);
	jmp_ptr(cb, target1);
	break;
	}
	}

	static codegen_status_t
	gen_branchunless(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	int32_t jump_offset = (int32_t)jit_get_arg(jit, 0);

	// Check for interrupts, but only on backward branches that may create loops
	if (jump_offset < 0) {
	uint8_t *side_exit = yjit_side_exit(jit, ctx);
	yjit_check_ints(cb, side_exit);
	}

	// Test if any bit (outside of the Qnil bit) is on
	// RUBY_Qfalse /* ...0000 0000 */
	// RUBY_Qnil /* ...0000 1000 */
	x86opnd_t val_opnd = ctx_stack_pop(ctx, 1);
	test(cb, val_opnd, imm_opnd(~Qnil));

	// Get the branch target instruction offsets
	uint32_t next_idx = jit_next_insn_idx(jit);
	uint32_t jump_idx = next_idx + jump_offset;
	blockid_t next_block = { jit->iseq, next_idx };
	blockid_t jump_block = { jit->iseq, jump_idx };

	// Generate the branch instructions
	gen_branch(
	jit,
	ctx,
	jump_block,
	ctx,
	next_block,
	ctx,
	gen_branchunless_branch
	);

	return YJIT_END_BLOCK;
	}

	static void
	gen_branchnil_branch(codeblock_t cb, uint8_t target0, uint8_t *target1, uint8_t shape)
	{
	switch (shape) {
	case SHAPE_NEXT0:
	jne_ptr(cb, target1);
	break;

	case SHAPE_NEXT1:
	je_ptr(cb, target0);
	break;

	case SHAPE_DEFAULT:
	je_ptr(cb, target0);
	jmp_ptr(cb, target1);
	break;
	}
	}

	static codegen_status_t
	gen_branchnil(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	int32_t jump_offset = (int32_t)jit_get_arg(jit, 0);

	// Check for interrupts, but only on backward branches that may create loops
	if (jump_offset < 0) {
	uint8_t *side_exit = yjit_side_exit(jit, ctx);
	yjit_check_ints(cb, side_exit);
	}

	// Test if the value is Qnil
	// RUBY_Qnil /* ...0000 1000 */
	x86opnd_t val_opnd = ctx_stack_pop(ctx, 1);
	cmp(cb, val_opnd, imm_opnd(Qnil));

	// Get the branch target instruction offsets
	uint32_t next_idx = jit_next_insn_idx(jit);
	uint32_t jump_idx = next_idx + jump_offset;
	blockid_t next_block = { jit->iseq, next_idx };
	blockid_t jump_block = { jit->iseq, jump_idx };

	// Generate the branch instructions
	gen_branch(
	jit,
	ctx,
	jump_block,
	ctx,
	next_block,
	ctx,
	gen_branchnil_branch
	);

	return YJIT_END_BLOCK;
	}

	static codegen_status_t
	gen_jump(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	int32_t jump_offset = (int32_t)jit_get_arg(jit, 0);

	// Check for interrupts, but only on backward branches that may create loops
	if (jump_offset < 0) {
	uint8_t *side_exit = yjit_side_exit(jit, ctx);
	yjit_check_ints(cb, side_exit);
	}

	// Get the branch target instruction offsets
	uint32_t jump_idx = jit_next_insn_idx(jit) + jump_offset;
	blockid_t jump_block = { jit->iseq, jump_idx };

	// Generate the jump instruction
	gen_direct_jump(
	jit,
	ctx,
	jump_block
	);

	return YJIT_END_BLOCK;
	}

	/*
	Guard that a stack operand has the same class as known_klass.
	Recompile as contingency if possible, or take side exit a last resort.
	*/
	static bool
	jit_guard_known_klass(jitstate_t jit, ctx_t ctx, VALUE known_klass, insn_opnd_t insn_opnd, VALUE sample_instance, const int max_chain_depth, uint8_t *side_exit)
	{
	val_type_t val_type = ctx_get_opnd_type(ctx, insn_opnd);

	if (known_klass == rb_cNilClass) {
	RUBY_ASSERT(!val_type.is_heap);
	if (val_type.type != ETYPE_NIL) {
	RUBY_ASSERT(val_type.type == ETYPE_UNKNOWN);

	ADD_COMMENT(cb, "guard object is nil");
	cmp(cb, REG0, imm_opnd(Qnil));
	jit_chain_guard(JCC_JNE, jit, ctx, max_chain_depth, side_exit);

	ctx_upgrade_opnd_type(ctx, insn_opnd, TYPE_NIL);
	}
	}
	else if (known_klass == rb_cTrueClass) {
	RUBY_ASSERT(!val_type.is_heap);
	if (val_type.type != ETYPE_TRUE) {
	RUBY_ASSERT(val_type.type == ETYPE_UNKNOWN);

	ADD_COMMENT(cb, "guard object is true");
	cmp(cb, REG0, imm_opnd(Qtrue));
	jit_chain_guard(JCC_JNE, jit, ctx, max_chain_depth, side_exit);

	ctx_upgrade_opnd_type(ctx, insn_opnd, TYPE_TRUE);
	}
	}
	else if (known_klass == rb_cFalseClass) {
	RUBY_ASSERT(!val_type.is_heap);
	if (val_type.type != ETYPE_FALSE) {
	RUBY_ASSERT(val_type.type == ETYPE_UNKNOWN);

	ADD_COMMENT(cb, "guard object is false");
	STATIC_ASSERT(qfalse_is_zero, Qfalse == 0);
	test(cb, REG0, REG0);
	jit_chain_guard(JCC_JNZ, jit, ctx, max_chain_depth, side_exit);

	ctx_upgrade_opnd_type(ctx, insn_opnd, TYPE_FALSE);
	}
	}
	else if (known_klass == rb_cInteger && FIXNUM_P(sample_instance)) {
	RUBY_ASSERT(!val_type.is_heap);
	// We will guard fixnum and bignum as though they were separate classes
	// BIGNUM can be handled by the general else case below
	if (val_type.type != ETYPE_FIXNUM \|\| !val_type.is_imm) {
	RUBY_ASSERT(val_type.type == ETYPE_UNKNOWN);

	ADD_COMMENT(cb, "guard object is fixnum");
	test(cb, REG0, imm_opnd(RUBY_FIXNUM_FLAG));
	jit_chain_guard(JCC_JZ, jit, ctx, max_chain_depth, side_exit);
	ctx_upgrade_opnd_type(ctx, insn_opnd, TYPE_FIXNUM);
	}
	}
	else if (known_klass == rb_cSymbol && STATIC_SYM_P(sample_instance)) {
	RUBY_ASSERT(!val_type.is_heap);
	// We will guard STATIC vs DYNAMIC as though they were separate classes
	// DYNAMIC symbols can be handled by the general else case below
	if (val_type.type != ETYPE_SYMBOL \|\| !val_type.is_imm) {
	RUBY_ASSERT(val_type.type == ETYPE_UNKNOWN);

	ADD_COMMENT(cb, "guard object is static symbol");
	STATIC_ASSERT(special_shift_is_8, RUBY_SPECIAL_SHIFT == 8);
	cmp(cb, REG0_8, imm_opnd(RUBY_SYMBOL_FLAG));
	jit_chain_guard(JCC_JNE, jit, ctx, max_chain_depth, side_exit);
	ctx_upgrade_opnd_type(ctx, insn_opnd, TYPE_STATIC_SYMBOL);
	}
	}
	else if (known_klass == rb_cFloat && FLONUM_P(sample_instance)) {
	RUBY_ASSERT(!val_type.is_heap);
	if (val_type.type != ETYPE_FLONUM \|\| !val_type.is_imm) {
	RUBY_ASSERT(val_type.type == ETYPE_UNKNOWN);

	// We will guard flonum vs heap float as though they were separate classes
	ADD_COMMENT(cb, "guard object is flonum");
	mov(cb, REG1, REG0);
	and(cb, REG1, imm_opnd(RUBY_FLONUM_MASK));
	cmp(cb, REG1, imm_opnd(RUBY_FLONUM_FLAG));
	jit_chain_guard(JCC_JNE, jit, ctx, max_chain_depth, side_exit);
	ctx_upgrade_opnd_type(ctx, insn_opnd, TYPE_FLONUM);
	}
	}
	else if (FL_TEST(known_klass, FL_SINGLETON) && sample_instance == rb_attr_get(known_klass, id__attached__)) {
	// Singleton classes are attached to one specific object, so we can
	// avoid one memory access (and potentially the is_heap check) by
	// looking for the expected object directly.
	// Note that in case the sample instance has a singleton class that
	// doesn't attach to the sample instance, it means the sample instance
	// has an empty singleton class that hasn't been materialized yet. In
	// this case, comparing against the sample instance doesn't gurantee
	// that its singleton class is empty, so we can't avoid the memory
	// access. As an example, `Object.new.singleton_class` is an object in
	// this situation.
	ADD_COMMENT(cb, "guard known object with singleton class");
	// TODO: jit_mov_gc_ptr keeps a strong reference, which leaks the object.
	jit_mov_gc_ptr(jit, cb, REG1, sample_instance);
	cmp(cb, REG0, REG1);
	jit_chain_guard(JCC_JNE, jit, ctx, max_chain_depth, side_exit);
	}
	else {
	RUBY_ASSERT(!val_type.is_imm);

	// Check that the receiver is a heap object
	// Note: if we get here, the class doesn't have immediate instances.
	if (!val_type.is_heap) {
	ADD_COMMENT(cb, "guard not immediate");
	RUBY_ASSERT(Qfalse < Qnil);
	test(cb, REG0, imm_opnd(RUBY_IMMEDIATE_MASK));
	jit_chain_guard(JCC_JNZ, jit, ctx, max_chain_depth, side_exit);
	cmp(cb, REG0, imm_opnd(Qnil));
	jit_chain_guard(JCC_JBE, jit, ctx, max_chain_depth, side_exit);

	ctx_upgrade_opnd_type(ctx, insn_opnd, TYPE_HEAP);
	}

	x86opnd_t klass_opnd = mem_opnd(64, REG0, offsetof(struct RBasic, klass));

	// Bail if receiver class is different from known_klass
	// TODO: jit_mov_gc_ptr keeps a strong reference, which leaks the class.
	ADD_COMMENT(cb, "guard known class");
	jit_mov_gc_ptr(jit, cb, REG1, known_klass);
	cmp(cb, klass_opnd, REG1);
	jit_chain_guard(JCC_JNE, jit, ctx, max_chain_depth, side_exit);
	}

	return true;
	}

	// Generate ancestry guard for protected callee.
	// Calls to protected callees only go through when self.is_a?(klass_that_defines_the_callee).
	static void
	jit_protected_callee_ancestry_guard(jitstate_t jit, codeblock_t cb, const rb_callable_method_entry_t cme, uint8_t side_exit)
	{
	// See vm_call_method().
	mov(cb, C_ARG_REGS[0], member_opnd(REG_CFP, rb_control_frame_t, self));
	jit_mov_gc_ptr(jit, cb, C_ARG_REGS[1], cme->defined_class);
	// Note: PC isn't written to current control frame as rb_is_kind_of() shouldn't raise.
	// VALUE rb_obj_is_kind_of(VALUE obj, VALUE klass);
	call_ptr(cb, REG0, (void *)&rb_obj_is_kind_of);
	test(cb, RAX, RAX);
	jz_ptr(cb, COUNTED_EXIT(side_exit, send_se_protected_check_failed));
	}

	// Return true when the codegen function generates code.
	// known_recv_klass is non-NULL when the caller has used jit_guard_known_klass().
	// See yjit_reg_method().
	typedef bool (method_codegen_t)(jitstate_t jit, ctx_t ctx, const struct rb_callinfo ci, const rb_callable_method_entry_t cme, rb_iseq_t block, const int32_t argc, VALUE *known_recv_klass);

	// Register a specialized codegen function for a particular method. Note that
	// the if the function returns true, the code it generates runs without a
	// control frame and without interrupt checks. To avoid creating observable
	// behavior changes, the codegen function should only target simple code paths
	// that do not allocate and do not make method calls.
	static void
	yjit_reg_method(VALUE klass, const char *mid_str, method_codegen_t gen_fn)
	{
	ID mid = rb_intern(mid_str);
	const rb_method_entry_t *me = rb_method_entry_at(klass, mid);

	if (!me) {
	rb_bug("undefined optimized method: %s", rb_id2name(mid));
	}

	// For now, only cfuncs are supported
	RUBY_ASSERT(me && me->def);
	RUBY_ASSERT(me->def->type == VM_METHOD_TYPE_CFUNC);

	st_insert(yjit_method_codegen_table, (st_data_t)me->def->method_serial, (st_data_t)gen_fn);
	}

	// Codegen for rb_obj_not().
	// Note, caller is responsible for generating all the right guards, including
	// arity guards.
	static bool
	jit_rb_obj_not(jitstate_t jit, ctx_t ctx, const struct rb_callinfo ci, const rb_callable_method_entry_t cme, rb_iseq_t block, const int32_t argc, VALUE known_recv_klass)
	{
	const val_type_t recv_opnd = ctx_get_opnd_type(ctx, OPND_STACK(0));

	if (recv_opnd.type == ETYPE_NIL \|\| recv_opnd.type == ETYPE_FALSE) {
	ADD_COMMENT(cb, "rb_obj_not(nil_or_false)");
	ctx_stack_pop(ctx, 1);
	x86opnd_t out_opnd = ctx_stack_push(ctx, TYPE_TRUE);
	mov(cb, out_opnd, imm_opnd(Qtrue));
	}
	else if (recv_opnd.is_heap \|\| recv_opnd.type != ETYPE_UNKNOWN) {
	// Note: recv_opnd.type != ETYPE_NIL && recv_opnd.type != ETYPE_FALSE.
	ADD_COMMENT(cb, "rb_obj_not(truthy)");
	ctx_stack_pop(ctx, 1);
	x86opnd_t out_opnd = ctx_stack_push(ctx, TYPE_FALSE);
	mov(cb, out_opnd, imm_opnd(Qfalse));
	}
	else {
	// jit_guard_known_klass() already ran on the receiver which should
	// have deduced deduced the type of the receiver. This case should be
	// rare if not unreachable.
	return false;
	}
	return true;
	}

	// Codegen for rb_true()
	static bool
	jit_rb_true(jitstate_t jit, ctx_t ctx, const struct rb_callinfo ci, const rb_callable_method_entry_t cme, rb_iseq_t block, const int32_t argc, VALUE known_recv_klass)
	{
	ADD_COMMENT(cb, "nil? == true");
	ctx_stack_pop(ctx, 1);
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_TRUE);
	mov(cb, stack_ret, imm_opnd(Qtrue));
	return true;
	}

	// Codegen for rb_false()
	static bool
	jit_rb_false(jitstate_t jit, ctx_t ctx, const struct rb_callinfo ci, const rb_callable_method_entry_t cme, rb_iseq_t block, const int32_t argc, VALUE known_recv_klass)
	{
	ADD_COMMENT(cb, "nil? == false");
	ctx_stack_pop(ctx, 1);
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_FALSE);
	mov(cb, stack_ret, imm_opnd(Qfalse));
	return true;
	}

	// Codegen for rb_obj_equal()
	// object identity comparison
	static bool
	jit_rb_obj_equal(jitstate_t jit, ctx_t ctx, const struct rb_callinfo ci, const rb_callable_method_entry_t cme, rb_iseq_t block, const int32_t argc, VALUE known_recv_klass)
	{
	ADD_COMMENT(cb, "equal?");
	x86opnd_t obj1 = ctx_stack_pop(ctx, 1);
	x86opnd_t obj2 = ctx_stack_pop(ctx, 1);

	mov(cb, REG0, obj1);
	cmp(cb, REG0, obj2);
	mov(cb, REG0, imm_opnd(Qtrue));
	mov(cb, REG1, imm_opnd(Qfalse));
	cmovne(cb, REG0, REG1);

	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_IMM);
	mov(cb, stack_ret, REG0);
	return true;
	}

	static VALUE
	yjit_str_bytesize(VALUE str)
	{
	return LONG2NUM(RSTRING_LEN(str));
	}

	static bool
	jit_rb_str_bytesize(jitstate_t jit, ctx_t ctx, const struct rb_callinfo ci, const rb_callable_method_entry_t cme, rb_iseq_t block, const int32_t argc, VALUE known_recv_klass)
	{
	ADD_COMMENT(cb, "String#bytesize");

	x86opnd_t recv = ctx_stack_pop(ctx, 1);
	mov(cb, C_ARG_REGS[0], recv);
	call_ptr(cb, REG0, (void *)&yjit_str_bytesize);

	x86opnd_t out_opnd = ctx_stack_push(ctx, TYPE_FIXNUM);
	mov(cb, out_opnd, RAX);

	return true;
	}

	// Codegen for rb_str_to_s()
	// When String#to_s is called on a String instance, the method returns self and
	// most of the overhead comes from setting up the method call. We observed that
	// this situation happens a lot in some workloads.
	static bool
	jit_rb_str_to_s(jitstate_t jit, ctx_t ctx, const struct rb_callinfo ci, const rb_callable_method_entry_t cme, rb_iseq_t block, const int32_t argc, VALUE recv_known_klass)
	{
	if (recv_known_klass && *recv_known_klass == rb_cString) {
	ADD_COMMENT(cb, "to_s on plain string");
	// The method returns the receiver, which is already on the stack.
	// No stack movement.
	return true;
	}
	return false;
	}

	static bool
	jit_thread_s_current(jitstate_t jit, ctx_t ctx, const struct rb_callinfo ci, const rb_callable_method_entry_t cme, rb_iseq_t block, const int32_t argc, VALUE recv_known_klass)
	{
	ADD_COMMENT(cb, "Thread.current");
	ctx_stack_pop(ctx, 1);

	// ec->thread_ptr
	mov(cb, REG0, member_opnd(REG_EC, rb_execution_context_t, thread_ptr));

	// thread->self
	mov(cb, REG0, member_opnd(REG0, rb_thread_t, self));

	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_HEAP);
	mov(cb, stack_ret, REG0);
	return true;
	}

	// Check if we know how to codegen for a particular cfunc method
	static method_codegen_t
	lookup_cfunc_codegen(const rb_method_definition_t *def)
	{
	method_codegen_t gen_fn;
	if (st_lookup(yjit_method_codegen_table, def->method_serial, (st_data_t *)&gen_fn)) {
	return gen_fn;
	}
	return NULL;
	}

	// Is anyone listening for :c_call and :c_return event currently?
	static bool
	c_method_tracing_currently_enabled(const jitstate_t *jit)
	{
	rb_event_flag_t tracing_events;
	if (rb_multi_ractor_p()) {
	tracing_events = ruby_vm_event_enabled_global_flags;
	}
	else {
	// At the time of writing, events are never removed from
	// ruby_vm_event_enabled_global_flags so always checking using it would
	// mean we don't compile even after tracing is disabled.
	tracing_events = rb_ec_ractor_hooks(jit->ec)->events;
	}

	return tracing_events & (RUBY_EVENT_C_CALL \| RUBY_EVENT_C_RETURN);
	}

	static codegen_status_t
	gen_send_cfunc(jitstate_t jit, ctx_t ctx, const struct rb_callinfo ci, const rb_callable_method_entry_t cme, rb_iseq_t block, const int32_t argc, VALUE recv_known_klass)
	{
	const rb_method_cfunc_t *cfunc = UNALIGNED_MEMBER_PTR(cme->def, body.cfunc);

	// If the function expects a Ruby array of arguments
	if (cfunc->argc < 0 && cfunc->argc != -1) {
	GEN_COUNTER_INC(cb, send_cfunc_ruby_array_varg);
	return YJIT_CANT_COMPILE;
	}

	// If the argument count doesn't match
	if (cfunc->argc >= 0 && cfunc->argc != argc) {
	GEN_COUNTER_INC(cb, send_cfunc_argc_mismatch);
	return YJIT_CANT_COMPILE;
	}

	// Don't JIT functions that need C stack arguments for now
	if (cfunc->argc >= 0 && argc + 1 > NUM_C_ARG_REGS) {
	GEN_COUNTER_INC(cb, send_cfunc_toomany_args);
	return YJIT_CANT_COMPILE;
	}

	if (c_method_tracing_currently_enabled(jit)) {
	// Don't JIT if tracing c_call or c_return
	GEN_COUNTER_INC(cb, send_cfunc_tracing);
	return YJIT_CANT_COMPILE;
	}

	// Delegate to codegen for C methods if we have it.
	{
	method_codegen_t known_cfunc_codegen;
	if ((known_cfunc_codegen = lookup_cfunc_codegen(cme->def))) {
	if (known_cfunc_codegen(jit, ctx, ci, cme, block, argc, recv_known_klass)) {
	// cfunc codegen generated code. Terminate the block so
	// there isn't multiple calls in the same block.
	jit_jump_to_next_insn(jit, ctx);
	return YJIT_END_BLOCK;
	}
	}
	}

	// Callee method ID
	//ID mid = vm_ci_mid(ci);
	//printf("JITting call to C function \"%s\", argc: %lu\n", rb_id2name(mid), argc);
	//print_str(cb, "");
	//print_str(cb, "calling CFUNC:");
	//print_str(cb, rb_id2name(mid));
	//print_str(cb, "recv");
	//print_ptr(cb, recv);

	// Create a size-exit to fall back to the interpreter
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	// Check for interrupts
	yjit_check_ints(cb, side_exit);

	// Stack overflow check
	// #define CHECK_VM_STACK_OVERFLOW0(cfp, sp, margin)
	// REG_CFP <= REG_SP + 4 * sizeof(VALUE) + sizeof(rb_control_frame_t)
	lea(cb, REG0, ctx_sp_opnd(ctx, sizeof(VALUE) * 4 + 2 * sizeof(rb_control_frame_t)));
	cmp(cb, REG_CFP, REG0);
	jle_ptr(cb, COUNTED_EXIT(side_exit, send_se_cf_overflow));

	// Points to the receiver operand on the stack
	x86opnd_t recv = ctx_stack_opnd(ctx, argc);

	// Store incremented PC into current control frame in case callee raises.
	jit_save_pc(jit, REG0);

	if (block) {
	// Change cfp->block_code in the current frame. See vm_caller_setup_arg_block().
	// VM_CFP_TO_CAPTURED_BLCOK does &cfp->self, rb_captured_block->code.iseq aliases
	// with cfp->block_code.
	jit_mov_gc_ptr(jit, cb, REG0, (VALUE)block);
	mov(cb, member_opnd(REG_CFP, rb_control_frame_t, block_code), REG0);
	}

	// Increment the stack pointer by 3 (in the callee)
	// sp += 3
	lea(cb, REG0, ctx_sp_opnd(ctx, sizeof(VALUE) * 3));

	// Write method entry at sp[-3]
	// sp[-3] = me;
	// Put compile time cme into REG1. It's assumed to be valid because we are notified when
	// any cme we depend on become outdated. See rb_yjit_method_lookup_change().
	jit_mov_gc_ptr(jit, cb, REG1, (VALUE)cme);
	mov(cb, mem_opnd(64, REG0, 8 * -3), REG1);

	// Write block handler at sp[-2]
	// sp[-2] = block_handler;
	if (block) {
	// reg1 = VM_BH_FROM_ISEQ_BLOCK(VM_CFP_TO_CAPTURED_BLOCK(reg_cfp));
	lea(cb, REG1, member_opnd(REG_CFP, rb_control_frame_t, self));
	or(cb, REG1, imm_opnd(1));
	mov(cb, mem_opnd(64, REG0, 8 * -2), REG1);
	}
	else {
	mov(cb, mem_opnd(64, REG0, 8 * -2), imm_opnd(VM_BLOCK_HANDLER_NONE));
	}

	// Write env flags at sp[-1]
	// sp[-1] = frame_type;
	uint64_t frame_type = VM_FRAME_MAGIC_CFUNC \| VM_FRAME_FLAG_CFRAME \| VM_ENV_FLAG_LOCAL;
	mov(cb, mem_opnd(64, REG0, 8 * -1), imm_opnd(frame_type));

	// Allocate a new CFP (ec->cfp--)
	sub(
	cb,
	member_opnd(REG_EC, rb_execution_context_t, cfp),
	imm_opnd(sizeof(rb_control_frame_t))
	);

	// Setup the new frame
	// *cfp = (const struct rb_control_frame_struct) {
	// .pc = 0,
	// .sp = sp,
	// .iseq = 0,
	// .self = recv,
	// .ep = sp - 1,
	// .block_code = 0,
	// .__bp__ = sp,
	// };
	mov(cb, REG1, member_opnd(REG_EC, rb_execution_context_t, cfp));
	mov(cb, member_opnd(REG1, rb_control_frame_t, pc), imm_opnd(0));
	mov(cb, member_opnd(REG1, rb_control_frame_t, sp), REG0);
	mov(cb, member_opnd(REG1, rb_control_frame_t, iseq), imm_opnd(0));
	mov(cb, member_opnd(REG1, rb_control_frame_t, block_code), imm_opnd(0));
	mov(cb, member_opnd(REG1, rb_control_frame_t, __bp__), REG0);
	sub(cb, REG0, imm_opnd(sizeof(VALUE)));
	mov(cb, member_opnd(REG1, rb_control_frame_t, ep), REG0);
	mov(cb, REG0, recv);
	mov(cb, member_opnd(REG1, rb_control_frame_t, self), REG0);

	// Verify that we are calling the right function
	if (YJIT_CHECK_MODE > 0) {
	// Call check_cfunc_dispatch
	mov(cb, C_ARG_REGS[0], recv);
	jit_mov_gc_ptr(jit, cb, C_ARG_REGS[1], (VALUE)ci);
	mov(cb, C_ARG_REGS[2], const_ptr_opnd((void *)cfunc->func));
	jit_mov_gc_ptr(jit, cb, C_ARG_REGS[3], (VALUE)cme);
	call_ptr(cb, REG0, (void *)&check_cfunc_dispatch);
	}

	// Copy SP into RAX because REG_SP will get overwritten
	lea(cb, RAX, ctx_sp_opnd(ctx, 0));

	// Pop the C function arguments from the stack (in the caller)
	ctx_stack_pop(ctx, argc + 1);

	// Write interpreter SP into CFP.
	// Needed in case the callee yields to the block.
	jit_save_sp(jit, ctx);

	// Non-variadic method
	if (cfunc->argc >= 0) {
	// Copy the arguments from the stack to the C argument registers
	// self is the 0th argument and is at index argc from the stack top
	for (int32_t i = 0; i < argc + 1; ++i)
	{
	x86opnd_t stack_opnd = mem_opnd(64, RAX, -(argc + 1 - i) * SIZEOF_VALUE);
	x86opnd_t c_arg_reg = C_ARG_REGS[i];
	mov(cb, c_arg_reg, stack_opnd);
	}
	}
	// Variadic method
	if (cfunc->argc == -1) {
	// The method gets a pointer to the first argument
	// rb_f_puts(int argc, VALUE *argv, VALUE recv)
	mov(cb, C_ARG_REGS[0], imm_opnd(argc));
	lea(cb, C_ARG_REGS[1], mem_opnd(64, RAX, -(argc) * SIZEOF_VALUE));
	mov(cb, C_ARG_REGS[2], mem_opnd(64, RAX, -(argc + 1) * SIZEOF_VALUE));
	}

	// Call the C function
	// VALUE ret = (cfunc->func)(recv, argv[0], argv[1]);
	// cfunc comes from compile-time cme->def, which we assume to be stable.
	// Invalidation logic is in rb_yjit_method_lookup_change()
	call_ptr(cb, REG0, (void*)cfunc->func);

	// Record code position for TracePoint patching. See full_cfunc_return().
	record_global_inval_patch(cb, outline_full_cfunc_return_pos);

	// Push the return value on the Ruby stack
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, stack_ret, RAX);

	// Pop the stack frame (ec->cfp++)
	add(
	cb,
	member_opnd(REG_EC, rb_execution_context_t, cfp),
	imm_opnd(sizeof(rb_control_frame_t))
	);

	// cfunc calls may corrupt types
	ctx_clear_local_types(ctx);

	// Note: the return block of gen_send_iseq() has ctx->sp_offset == 1
	// which allows for sharing the same successor.

	// Jump (fall through) to the call continuation block
	// We do this to end the current block after the call
	jit_jump_to_next_insn(jit, ctx);
	return YJIT_END_BLOCK;
	}

	static void
	gen_return_branch(codeblock_t cb, uint8_t target0, uint8_t *target1, uint8_t shape)
	{
	switch (shape) {
	case SHAPE_NEXT0:
	case SHAPE_NEXT1:
	RUBY_ASSERT(false);
	break;

	case SHAPE_DEFAULT:
	mov(cb, REG0, const_ptr_opnd(target0));
	mov(cb, member_opnd(REG_CFP, rb_control_frame_t, jit_return), REG0);
	break;
	}
	}

	// Returns whether the iseq only needs positional (lead) argument setup.
	static bool
	iseq_lead_only_arg_setup_p(const rb_iseq_t *iseq)
	{
	// When iseq->body->local_iseq == iseq, setup_parameters_complex()
	// doesn't do anything to setup the block parameter.
	bool takes_block = iseq->body->param.flags.has_block;
	return (!takes_block \|\| iseq->body->local_iseq == iseq) &&
	iseq->body->param.flags.has_opt == false &&
	iseq->body->param.flags.has_rest == false &&
	iseq->body->param.flags.has_post == false &&
	iseq->body->param.flags.has_kw == false &&
	iseq->body->param.flags.has_kwrest == false &&
	iseq->body->param.flags.accepts_no_kwarg == false;
	}

	bool rb_iseq_only_optparam_p(const rb_iseq_t *iseq);
	bool rb_iseq_only_kwparam_p(const rb_iseq_t *iseq);

	// If true, the iseq is leaf and it can be replaced by a single C call.
	static bool
	rb_leaf_invokebuiltin_iseq_p(const rb_iseq_t *iseq)
	{
	unsigned int invokebuiltin_len = insn_len(BIN(opt_invokebuiltin_delegate_leave));
	unsigned int leave_len = insn_len(BIN(leave));

	return (iseq->body->iseq_size == (invokebuiltin_len + leave_len) &&
	rb_vm_insn_addr2opcode((void *)iseq->body->iseq_encoded[0]) == BIN(opt_invokebuiltin_delegate_leave) &&
	rb_vm_insn_addr2opcode((void *)iseq->body->iseq_encoded[invokebuiltin_len]) == BIN(leave) &&
	iseq->body->builtin_inline_p
	);
	}

	// Return an rb_builtin_function if the iseq contains only that leaf builtin function.
	static const struct rb_builtin_function*
	rb_leaf_builtin_function(const rb_iseq_t *iseq)
	{
	if (!rb_leaf_invokebuiltin_iseq_p(iseq))
	return NULL;
	return (const struct rb_builtin_function *)iseq->body->iseq_encoded[1];
	}

	static codegen_status_t
	gen_send_iseq(jitstate_t jit, ctx_t ctx, const struct rb_callinfo ci, const rb_callable_method_entry_t cme, rb_iseq_t *block, const int32_t argc)
	{
	const rb_iseq_t *iseq = def_iseq_ptr(cme->def);

	// When you have keyword arguments, there is an extra object that gets
	// placed on the stack the represents a bitmap of the keywords that were not
	// specified at the call site. We need to keep track of the fact that this
	// value is present on the stack in order to properly set up the callee's
	// stack pointer.
	bool doing_kw_call = false;

	if (vm_ci_flag(ci) & VM_CALL_TAILCALL) {
	// We can't handle tailcalls
	GEN_COUNTER_INC(cb, send_iseq_tailcall);
	return YJIT_CANT_COMPILE;
	}

	// Arity handling and optional parameter setup
	int num_params = iseq->body->param.size;
	uint32_t start_pc_offset = 0;

	if (iseq_lead_only_arg_setup_p(iseq)) {
	// If we have keyword arguments being passed to a callee that only takes
	// positionals, then we need to allocate a hash. For now we're going to
	// call that too complex and bail.
	if (vm_ci_flag(ci) & VM_CALL_KWARG) {
	GEN_COUNTER_INC(cb, send_iseq_complex_callee);
	return YJIT_CANT_COMPILE;
	}

	num_params = iseq->body->param.lead_num;

	if (num_params != argc) {
	GEN_COUNTER_INC(cb, send_iseq_arity_error);
	return YJIT_CANT_COMPILE;
	}
	}
	else if (rb_iseq_only_optparam_p(iseq)) {
	// If we have keyword arguments being passed to a callee that only takes
	// positionals and optionals, then we need to allocate a hash. For now
	// we're going to call that too complex and bail.
	if (vm_ci_flag(ci) & VM_CALL_KWARG) {
	GEN_COUNTER_INC(cb, send_iseq_complex_callee);
	return YJIT_CANT_COMPILE;
	}

	// These are iseqs with 0 or more required parameters followed by 1
	// or more optional parameters.
	// We follow the logic of vm_call_iseq_setup_normal_opt_start()
	// and these are the preconditions required for using that fast path.
	RUBY_ASSERT(vm_ci_markable(ci) && ((vm_ci_flag(ci) &
	(VM_CALL_KW_SPLAT \| VM_CALL_KWARG \| VM_CALL_ARGS_SPLAT)) == 0));

	const int required_num = iseq->body->param.lead_num;
	const int opts_filled = argc - required_num;
	const int opt_num = iseq->body->param.opt_num;

	if (opts_filled < 0 \|\| opts_filled > opt_num) {
	GEN_COUNTER_INC(cb, send_iseq_arity_error);
	return YJIT_CANT_COMPILE;
	}

	num_params -= opt_num - opts_filled;
	start_pc_offset = (uint32_t)iseq->body->param.opt_table[opts_filled];
	}
	else if (rb_iseq_only_kwparam_p(iseq)) {
	const int lead_num = iseq->body->param.lead_num;

	if (vm_ci_flag(ci) & VM_CALL_KWARG) {
	// Here we're calling a method with keyword arguments and specifying
	// keyword arguments at this call site.

	// This struct represents the metadata about the caller-specified
	// keyword arguments.
	const struct rb_callinfo_kwarg *kw_arg = vm_ci_kwarg(ci);

	// This struct represents the metadata about the callee-specified
	// keyword parameters.
	const struct rb_iseq_param_keyword *keyword = iseq->body->param.keyword;

	if ((kw_arg->keyword_len != keyword->num) \|\| (lead_num != argc - kw_arg->keyword_len)) {
	// Here the method being called specifies optional and required
	// keyword arguments and the callee is not specifying every one
	// of them.
	GEN_COUNTER_INC(cb, send_iseq_kwargs_req_and_opt_missing);
	return YJIT_CANT_COMPILE;
	}

	// This is the list of keyword arguments that the callee specified
	// in its initial declaration.
	const ID *callee_kwargs = keyword->table;

	// Here we're going to build up a list of the IDs that correspond to
	// the caller-specified keyword arguments. If they're not in the
	// same order as the order specified in the callee declaration, then
	// we're going to need to generate some code to swap values around
	// on the stack.
	ID *caller_kwargs = ALLOCA_N(VALUE, kw_arg->keyword_len);
	for (int kwarg_idx = 0; kwarg_idx < kw_arg->keyword_len; kwarg_idx++)
	caller_kwargs[kwarg_idx] = SYM2ID(kw_arg->keywords[kwarg_idx]);

	// First, we're going to be sure that the names of every
	// caller-specified keyword argument correspond to a name in the
	// list of callee-specified keyword parameters.
	for (int caller_idx = 0; caller_idx < kw_arg->keyword_len; caller_idx++) {
	int callee_idx;

	for (callee_idx = 0; callee_idx < keyword->num; callee_idx++) {
	if (caller_kwargs[caller_idx] == callee_kwargs[callee_idx]) {
	break;
	}
	}

	// If the keyword was never found, then we know we have a
	// mismatch in the names of the keyword arguments, so we need to
	// bail.
	if (callee_idx == keyword->num) {
	GEN_COUNTER_INC(cb, send_iseq_kwargs_mismatch);
	return YJIT_CANT_COMPILE;
	}
	}

	doing_kw_call = true;
	}
	else if (argc == lead_num) {
	// Here we are calling a method that accepts keyword arguments
	// (optional or required) but we're not passing any keyword
	// arguments at this call site

	GEN_COUNTER_INC(cb, send_iseq_kwargs_none_passed);
	return YJIT_CANT_COMPILE;
	}
	else {
	GEN_COUNTER_INC(cb, send_iseq_complex_callee);
	return YJIT_CANT_COMPILE;
	}
	}
	else {
	// Only handle iseqs that have simple parameter setup.
	// See vm_callee_setup_arg().
	GEN_COUNTER_INC(cb, send_iseq_complex_callee);
	return YJIT_CANT_COMPILE;
	}

	// Number of locals that are not parameters
	const int num_locals = iseq->body->local_table_size - num_params;

	// Create a size-exit to fall back to the interpreter
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	// Check for interrupts
	yjit_check_ints(cb, side_exit);

	const struct rb_builtin_function *leaf_builtin = rb_leaf_builtin_function(iseq);

	if (leaf_builtin && !block && leaf_builtin->argc + 1 <= NUM_C_ARG_REGS) {
	ADD_COMMENT(cb, "inlined leaf builtin");

	// Call the builtin func (ec, recv, arg1, arg2, ...)
	mov(cb, C_ARG_REGS[0], REG_EC);

	// Copy self and arguments
	for (int32_t i = 0; i < leaf_builtin->argc + 1; i++) {
	x86opnd_t stack_opnd = ctx_stack_opnd(ctx, leaf_builtin->argc - i);
	x86opnd_t c_arg_reg = C_ARG_REGS[i + 1];
	mov(cb, c_arg_reg, stack_opnd);
	}
	ctx_stack_pop(ctx, leaf_builtin->argc + 1);
	call_ptr(cb, REG0, (void *)leaf_builtin->func_ptr);

	// Push the return value
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, stack_ret, RAX);

	// Note: assuming that the leaf builtin doesn't change local variables here.
	// Seems like a safe assumption.

	return YJIT_KEEP_COMPILING;
	}

	// Stack overflow check
	// Note that vm_push_frame checks it against a decremented cfp, hence the multiply by 2.
	// #define CHECK_VM_STACK_OVERFLOW0(cfp, sp, margin)
	ADD_COMMENT(cb, "stack overflow check");
	lea(cb, REG0, ctx_sp_opnd(ctx, sizeof(VALUE) * (num_locals + iseq->body->stack_max) + 2 * sizeof(rb_control_frame_t)));
	cmp(cb, REG_CFP, REG0);
	jle_ptr(cb, COUNTED_EXIT(side_exit, send_se_cf_overflow));

	if (doing_kw_call) {
	// Here we're calling a method with keyword arguments and specifying
	// keyword arguments at this call site.
	const int lead_num = iseq->body->param.lead_num;

	// This struct represents the metadata about the caller-specified
	// keyword arguments.
	const struct rb_callinfo_kwarg *kw_arg = vm_ci_kwarg(ci);

	// This struct represents the metadata about the callee-specified
	// keyword parameters.
	const struct rb_iseq_param_keyword *keyword = iseq->body->param.keyword;

	// Note: we are about to do argument shuffling for a keyword argument
	// call. The various checks for whether we can do it happened earlier
	// in this function.
	RUBY_ASSERT((kw_arg->keyword_len == keyword->num) && (lead_num == argc - kw_arg->keyword_len));

	// This is the list of keyword arguments that the callee specified
	// in its initial declaration.
	const ID *callee_kwargs = keyword->table;

	// Here we're going to build up a list of the IDs that correspond to
	// the caller-specified keyword arguments. If they're not in the
	// same order as the order specified in the callee declaration, then
	// we're going to need to generate some code to swap values around
	// on the stack.
	ID *caller_kwargs = ALLOCA_N(VALUE, kw_arg->keyword_len);
	for (int kwarg_idx = 0; kwarg_idx < kw_arg->keyword_len; kwarg_idx++)
	caller_kwargs[kwarg_idx] = SYM2ID(kw_arg->keywords[kwarg_idx]);

	// Next, we're going to loop through every keyword that was
	// specified by the caller and make sure that it's in the correct
	// place. If it's not we're going to swap it around with another one.
	for (int kwarg_idx = 0; kwarg_idx < kw_arg->keyword_len; kwarg_idx++) {
	ID callee_kwarg = callee_kwargs[kwarg_idx];

	// If the argument is already in the right order, then we don't
	// need to generate any code since the expected value is already
	// in the right place on the stack.
	if (callee_kwarg == caller_kwargs[kwarg_idx]) continue;

	// In this case the argument is not in the right place, so we
	// need to find its position where it _should_ be and swap with
	// that location.
	for (int swap_idx = kwarg_idx + 1; swap_idx < kw_arg->keyword_len; swap_idx++) {
	if (callee_kwarg == caller_kwargs[swap_idx]) {
	// First we're going to generate the code that is going
	// to perform the actual swapping at runtime.
	stack_swap(ctx, cb, argc - 1 - swap_idx - lead_num, argc - 1 - kwarg_idx - lead_num, REG1, REG0);

	// Next we're going to do some bookkeeping on our end so
	// that we know the order that the arguments are
	// actually in now.
	ID tmp = caller_kwargs[kwarg_idx];
	caller_kwargs[kwarg_idx] = caller_kwargs[swap_idx];
	caller_kwargs[swap_idx] = tmp;

	break;
	}
	}
	}

	// Keyword arguments cause a special extra local variable to be
	// pushed onto the stack that represents the parameters that weren't
	// explicitly given a value. Its value is a bitmap that corresponds
	// to the indices of the missing parameters. In this case since we
	// know every value was specified, we can just write the value 0.
	mov(cb, ctx_stack_opnd(ctx, -1), imm_opnd(INT2FIX(0)));
	}
	// Points to the receiver operand on the stack
	x86opnd_t recv = ctx_stack_opnd(ctx, argc);

	// Store the updated SP on the current frame (pop arguments and receiver)
	lea(cb, REG0, ctx_sp_opnd(ctx, sizeof(VALUE) * -(argc + 1)));
	mov(cb, member_opnd(REG_CFP, rb_control_frame_t, sp), REG0);

	// Store the next PC in the current frame
	jit_save_pc(jit, REG0);

	if (block) {
	// Change cfp->block_code in the current frame. See vm_caller_setup_arg_block().
	// VM_CFP_TO_CAPTURED_BLCOK does &cfp->self, rb_captured_block->code.iseq aliases
	// with cfp->block_code.
	jit_mov_gc_ptr(jit, cb, REG0, (VALUE)block);
	mov(cb, member_opnd(REG_CFP, rb_control_frame_t, block_code), REG0);
	}

	// Adjust the callee's stack pointer
	lea(cb, REG0, ctx_sp_opnd(ctx, sizeof(VALUE) * (3 + num_locals + doing_kw_call)));

	// Initialize local variables to Qnil
	for (int i = 0; i < num_locals; i++) {
	mov(cb, mem_opnd(64, REG0, sizeof(VALUE) * (i - num_locals - 3)), imm_opnd(Qnil));
	}

	// Put compile time cme into REG1. It's assumed to be valid because we are notified when
	// any cme we depend on become outdated. See rb_yjit_method_lookup_change().
	jit_mov_gc_ptr(jit, cb, REG1, (VALUE)cme);
	// Write method entry at sp[-3]
	// sp[-3] = me;
	mov(cb, mem_opnd(64, REG0, 8 * -3), REG1);

	// Write block handler at sp[-2]
	// sp[-2] = block_handler;
	if (block) {
	// reg1 = VM_BH_FROM_ISEQ_BLOCK(VM_CFP_TO_CAPTURED_BLOCK(reg_cfp));
	lea(cb, REG1, member_opnd(REG_CFP, rb_control_frame_t, self));
	or(cb, REG1, imm_opnd(1));
	mov(cb, mem_opnd(64, REG0, 8 * -2), REG1);
	}
	else {
	mov(cb, mem_opnd(64, REG0, 8 * -2), imm_opnd(VM_BLOCK_HANDLER_NONE));
	}

	// Write env flags at sp[-1]
	// sp[-1] = frame_type;
	uint64_t frame_type = VM_FRAME_MAGIC_METHOD \| VM_ENV_FLAG_LOCAL;
	mov(cb, mem_opnd(64, REG0, 8 * -1), imm_opnd(frame_type));

	// Allocate a new CFP (ec->cfp--)
	sub(cb, REG_CFP, imm_opnd(sizeof(rb_control_frame_t)));
	mov(cb, member_opnd(REG_EC, rb_execution_context_t, cfp), REG_CFP);

	// Setup the new frame
	// *cfp = (const struct rb_control_frame_struct) {
	// .pc = pc,
	// .sp = sp,
	// .iseq = iseq,
	// .self = recv,
	// .ep = sp - 1,
	// .block_code = 0,
	// .__bp__ = sp,
	// };
	mov(cb, REG1, recv);
	mov(cb, member_opnd(REG_CFP, rb_control_frame_t, self), REG1);
	mov(cb, REG_SP, REG0); // Switch to the callee's REG_SP
	mov(cb, member_opnd(REG_CFP, rb_control_frame_t, sp), REG0);
	mov(cb, member_opnd(REG_CFP, rb_control_frame_t, __bp__), REG0);
	sub(cb, REG0, imm_opnd(sizeof(VALUE)));
	mov(cb, member_opnd(REG_CFP, rb_control_frame_t, ep), REG0);
	jit_mov_gc_ptr(jit, cb, REG0, (VALUE)iseq);
	mov(cb, member_opnd(REG_CFP, rb_control_frame_t, iseq), REG0);
	mov(cb, member_opnd(REG_CFP, rb_control_frame_t, block_code), imm_opnd(0));

	// No need to set cfp->pc since the callee sets it whenever calling into routines
	// that could look at it through jit_save_pc().
	// mov(cb, REG0, const_ptr_opnd(start_pc));
	// mov(cb, member_opnd(REG_CFP, rb_control_frame_t, pc), REG0);

	// Stub so we can return to JITted code
	blockid_t return_block = { jit->iseq, jit_next_insn_idx(jit) };

	// Create a context for the callee
	ctx_t callee_ctx = DEFAULT_CTX;

	// Set the argument types in the callee's context
	for (int32_t arg_idx = 0; arg_idx < argc; ++arg_idx) {
	val_type_t arg_type = ctx_get_opnd_type(ctx, OPND_STACK(argc - arg_idx - 1));
	ctx_set_local_type(&callee_ctx, arg_idx, arg_type);
	}
	val_type_t recv_type = ctx_get_opnd_type(ctx, OPND_STACK(argc));
	ctx_upgrade_opnd_type(&callee_ctx, OPND_SELF, recv_type);

	// The callee might change locals through Kernel#binding and other means.
	ctx_clear_local_types(ctx);

	// Pop arguments and receiver in return context, push the return value
	// After the return, sp_offset will be 1. The codegen for leave writes
	// the return value in case of JIT-to-JIT return.
	ctx_t return_ctx = *ctx;
	ctx_stack_pop(&return_ctx, argc + 1);
	ctx_stack_push(&return_ctx, TYPE_UNKNOWN);
	return_ctx.sp_offset = 1;
	return_ctx.chain_depth = 0;

	// Write the JIT return address on the callee frame
	gen_branch(
	jit,
	ctx,
	return_block,
	&return_ctx,
	return_block,
	&return_ctx,
	gen_return_branch
	);

	//print_str(cb, "calling Ruby func:");
	//print_str(cb, rb_id2name(vm_ci_mid(ci)));

	// Directly jump to the entry point of the callee
	gen_direct_jump(
	jit,
	&callee_ctx,
	(blockid_t){ iseq, start_pc_offset }
	);

	return YJIT_END_BLOCK;
	}

	const rb_callable_method_entry_t *
	rb_aliased_callable_method_entry(const rb_callable_method_entry_t *me);

	static codegen_status_t
	gen_send_general(jitstate_t jit, ctx_t ctx, struct rb_call_data cd, rb_iseq_t block)
	{
	// Relevant definitions:
	// rb_execution_context_t : vm_core.h
	// invoker, cfunc logic : method.h, vm_method.c
	// rb_callinfo : vm_callinfo.h
	// rb_callable_method_entry_t : method.h
	// vm_call_cfunc_with_frame : vm_insnhelper.c
	//
	// For a general overview for how the interpreter calls methods,
	// see vm_call_method().

	const struct rb_callinfo *ci = cd->ci; // info about the call site

	int32_t argc = (int32_t)vm_ci_argc(ci);
	ID mid = vm_ci_mid(ci);

	// Don't JIT calls with keyword splat
	if (vm_ci_flag(ci) & VM_CALL_KW_SPLAT) {
	GEN_COUNTER_INC(cb, send_kw_splat);
	return YJIT_CANT_COMPILE;
	}

	// Don't JIT calls that aren't simple
	// Note, not using VM_CALL_ARGS_SIMPLE because sometimes we pass a block.
	if ((vm_ci_flag(ci) & VM_CALL_ARGS_SPLAT) != 0) {
	GEN_COUNTER_INC(cb, send_args_splat);
	return YJIT_CANT_COMPILE;
	}
	if ((vm_ci_flag(ci) & VM_CALL_ARGS_BLOCKARG) != 0) {
	GEN_COUNTER_INC(cb, send_block_arg);
	return YJIT_CANT_COMPILE;
	}

	// Defer compilation so we can specialize on class of receiver
	if (!jit_at_current_insn(jit)) {
	defer_compilation(jit, ctx);
	return YJIT_END_BLOCK;
	}

	VALUE comptime_recv = jit_peek_at_stack(jit, ctx, argc);
	VALUE comptime_recv_klass = CLASS_OF(comptime_recv);

	// Guard that the receiver has the same class as the one from compile time
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	// Points to the receiver operand on the stack
	x86opnd_t recv = ctx_stack_opnd(ctx, argc);
	insn_opnd_t recv_opnd = OPND_STACK(argc);
	mov(cb, REG0, recv);
	if (!jit_guard_known_klass(jit, ctx, comptime_recv_klass, recv_opnd, comptime_recv, SEND_MAX_DEPTH, side_exit)) {
	return YJIT_CANT_COMPILE;
	}

	// Do method lookup
	const rb_callable_method_entry_t *cme = rb_callable_method_entry(comptime_recv_klass, mid);
	if (!cme) {
	// TODO: counter
	return YJIT_CANT_COMPILE;
	}

	switch (METHOD_ENTRY_VISI(cme)) {
	case METHOD_VISI_PUBLIC:
	// Can always call public methods
	break;
	case METHOD_VISI_PRIVATE:
	if (!(vm_ci_flag(ci) & VM_CALL_FCALL)) {
	// Can only call private methods with FCALL callsites.
	// (at the moment they are callsites without a receiver or an explicit `self` receiver)
	return YJIT_CANT_COMPILE;
	}
	break;
	case METHOD_VISI_PROTECTED:
	jit_protected_callee_ancestry_guard(jit, cb, cme, side_exit);
	break;
	case METHOD_VISI_UNDEF:
	RUBY_ASSERT(false && "cmes should always have a visibility");
	break;
	}

	// Register block for invalidation
	RUBY_ASSERT(cme->called_id == mid);
	assume_method_lookup_stable(comptime_recv_klass, cme, jit->block);

	// To handle the aliased method case (VM_METHOD_TYPE_ALIAS)
	while (true) {
	// switch on the method type
	switch (cme->def->type) {
	case VM_METHOD_TYPE_ISEQ:
	return gen_send_iseq(jit, ctx, ci, cme, block, argc);
	case VM_METHOD_TYPE_CFUNC:
	if ((vm_ci_flag(ci) & VM_CALL_KWARG) != 0) {
	GEN_COUNTER_INC(cb, send_cfunc_kwargs);
	return YJIT_CANT_COMPILE;
	}
	return gen_send_cfunc(jit, ctx, ci, cme, block, argc, &comptime_recv_klass);
	case VM_METHOD_TYPE_IVAR:
	if (argc != 0) {
	// Argument count mismatch. Getters take no arguments.
	GEN_COUNTER_INC(cb, send_getter_arity);
	return YJIT_CANT_COMPILE;
	}
	if (c_method_tracing_currently_enabled(jit)) {
	// Can't generate code for firing c_call and c_return events
	// :attr-tracing:
	// Handling the C method tracing events for attr_accessor
	// methods is easier than regular C methods as we know the
	// "method" we are calling into never enables those tracing
	// events. Once global invalidation runs, the code for the
	// attr_accessor is invalidated and we exit at the closest
	// instruction boundary which is always outside of the body of
	// the attr_accessor code.
	GEN_COUNTER_INC(cb, send_cfunc_tracing);
	return YJIT_CANT_COMPILE;
	}

	mov(cb, REG0, recv);

	ID ivar_name = cme->def->body.attr.id;
	return gen_get_ivar(jit, ctx, SEND_MAX_DEPTH, comptime_recv, ivar_name, recv_opnd, side_exit);
	case VM_METHOD_TYPE_ATTRSET:
	if ((vm_ci_flag(ci) & VM_CALL_KWARG) != 0) {
	GEN_COUNTER_INC(cb, send_attrset_kwargs);
	return YJIT_CANT_COMPILE;
	}
	else if (argc != 1 \|\| !RB_TYPE_P(comptime_recv, T_OBJECT)) {
	GEN_COUNTER_INC(cb, send_ivar_set_method);
	return YJIT_CANT_COMPILE;
	}
	else if (c_method_tracing_currently_enabled(jit)) {
	// Can't generate code for firing c_call and c_return events
	// See :attr-tracing:
	GEN_COUNTER_INC(cb, send_cfunc_tracing);
	return YJIT_CANT_COMPILE;
	}
	else {
	ID ivar_name = cme->def->body.attr.id;
	return gen_set_ivar(jit, ctx, comptime_recv, comptime_recv_klass, ivar_name);
	}
	case VM_METHOD_TYPE_BMETHOD:
	GEN_COUNTER_INC(cb, send_bmethod);
	return YJIT_CANT_COMPILE;
	case VM_METHOD_TYPE_ZSUPER:
	GEN_COUNTER_INC(cb, send_zsuper_method);
	return YJIT_CANT_COMPILE;
	case VM_METHOD_TYPE_ALIAS: {
	// Retrieve the alised method and re-enter the switch
	cme = rb_aliased_callable_method_entry(cme);
	continue;
	}
	case VM_METHOD_TYPE_UNDEF:
	GEN_COUNTER_INC(cb, send_undef_method);
	return YJIT_CANT_COMPILE;
	case VM_METHOD_TYPE_NOTIMPLEMENTED:
	GEN_COUNTER_INC(cb, send_not_implemented_method);
	return YJIT_CANT_COMPILE;
	case VM_METHOD_TYPE_OPTIMIZED:
	GEN_COUNTER_INC(cb, send_optimized_method);
	return YJIT_CANT_COMPILE;
	case VM_METHOD_TYPE_MISSING:
	GEN_COUNTER_INC(cb, send_missing_method);
	return YJIT_CANT_COMPILE;
	case VM_METHOD_TYPE_REFINED:
	GEN_COUNTER_INC(cb, send_refined_method);
	return YJIT_CANT_COMPILE;
	// no default case so compiler issues a warning if this is not exhaustive
	}

	// Unreachable
	RUBY_ASSERT(false);
	}
	}

	static codegen_status_t
	gen_opt_send_without_block(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	struct rb_call_data cd = (struct rb_call_data )jit_get_arg(jit, 0);
	return gen_send_general(jit, ctx, cd, NULL);
	}

	static codegen_status_t
	gen_send(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	struct rb_call_data cd = (struct rb_call_data )jit_get_arg(jit, 0);
	rb_iseq_t block = (rb_iseq_t )jit_get_arg(jit, 1);
	return gen_send_general(jit, ctx, cd, block);
	}

	static codegen_status_t
	gen_invokesuper(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	struct rb_call_data cd = (struct rb_call_data )jit_get_arg(jit, 0);
	rb_iseq_t block = (rb_iseq_t )jit_get_arg(jit, 1);

	// Defer compilation so we can specialize on class of receiver
	if (!jit_at_current_insn(jit)) {
	defer_compilation(jit, ctx);
	return YJIT_END_BLOCK;
	}

	const rb_callable_method_entry_t *me = rb_vm_frame_method_entry(jit->ec->cfp);
	if (!me) {
	return YJIT_CANT_COMPILE;
	}

	// FIXME: We should track and invalidate this block when this cme is invalidated
	VALUE current_defined_class = me->defined_class;
	ID mid = me->def->original_id;

	if (me != rb_callable_method_entry(current_defined_class, me->called_id)) {
	// Though we likely could generate this call, as we are only concerned
	// with the method entry remaining valid, assume_method_lookup_stable
	// below requires that the method lookup matches as well
	return YJIT_CANT_COMPILE;
	}

	// vm_search_normal_superclass
	if (BUILTIN_TYPE(current_defined_class) == T_ICLASS && FL_TEST_RAW(RBASIC(current_defined_class)->klass, RMODULE_IS_REFINEMENT)) {
	return YJIT_CANT_COMPILE;
	}
	VALUE comptime_superclass = RCLASS_SUPER(RCLASS_ORIGIN(current_defined_class));

	const struct rb_callinfo *ci = cd->ci;
	int32_t argc = (int32_t)vm_ci_argc(ci);

	// Don't JIT calls that aren't simple
	// Note, not using VM_CALL_ARGS_SIMPLE because sometimes we pass a block.
	if ((vm_ci_flag(ci) & VM_CALL_ARGS_SPLAT) != 0) {
	GEN_COUNTER_INC(cb, send_args_splat);
	return YJIT_CANT_COMPILE;
	}
	if ((vm_ci_flag(ci) & VM_CALL_KWARG) != 0) {
	GEN_COUNTER_INC(cb, send_keywords);
	return YJIT_CANT_COMPILE;
	}
	if ((vm_ci_flag(ci) & VM_CALL_KW_SPLAT) != 0) {
	GEN_COUNTER_INC(cb, send_kw_splat);
	return YJIT_CANT_COMPILE;
	}
	if ((vm_ci_flag(ci) & VM_CALL_ARGS_BLOCKARG) != 0) {
	GEN_COUNTER_INC(cb, send_block_arg);
	return YJIT_CANT_COMPILE;
	}

	// Ensure we haven't rebound this method onto an incompatible class.
	// In the interpreter we try to avoid making this check by performing some
	// cheaper calculations first, but since we specialize on the method entry
	// and so only have to do this once at compile time this is fine to always
	// check and side exit.
	VALUE comptime_recv = jit_peek_at_stack(jit, ctx, argc);
	if (!rb_obj_is_kind_of(comptime_recv, current_defined_class)) {
	return YJIT_CANT_COMPILE;
	}

	// Do method lookup
	const rb_callable_method_entry_t *cme = rb_callable_method_entry(comptime_superclass, mid);

	if (!cme) {
	return YJIT_CANT_COMPILE;
	}

	// Check that we'll be able to write this method dispatch before generating checks
	switch (cme->def->type) {
	case VM_METHOD_TYPE_ISEQ:
	case VM_METHOD_TYPE_CFUNC:
	break;
	default:
	// others unimplemented
	return YJIT_CANT_COMPILE;
	}

	// Guard that the receiver has the same class as the one from compile time
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	if (jit->ec->cfp->ep[VM_ENV_DATA_INDEX_ME_CREF] != (VALUE)me) {
	// This will be the case for super within a block
	return YJIT_CANT_COMPILE;
	}

	ADD_COMMENT(cb, "guard known me");
	mov(cb, REG0, member_opnd(REG_CFP, rb_control_frame_t, ep));
	x86opnd_t ep_me_opnd = mem_opnd(64, REG0, SIZEOF_VALUE * VM_ENV_DATA_INDEX_ME_CREF);
	jit_mov_gc_ptr(jit, cb, REG1, (VALUE)me);
	cmp(cb, ep_me_opnd, REG1);
	jne_ptr(cb, COUNTED_EXIT(side_exit, invokesuper_me_changed));

	if (!block) {
	// Guard no block passed
	// rb_vm_frame_block_handler(GET_EC()->cfp) == VM_BLOCK_HANDLER_NONE
	// note, we assume VM_ASSERT(VM_ENV_LOCAL_P(ep))
	//
	// TODO: this could properly forward the current block handler, but
	// would require changes to gen_send_*
	ADD_COMMENT(cb, "guard no block given");
	// EP is in REG0 from above
	x86opnd_t ep_specval_opnd = mem_opnd(64, REG0, SIZEOF_VALUE * VM_ENV_DATA_INDEX_SPECVAL);
	cmp(cb, ep_specval_opnd, imm_opnd(VM_BLOCK_HANDLER_NONE));
	jne_ptr(cb, COUNTED_EXIT(side_exit, invokesuper_block));
	}

	// Points to the receiver operand on the stack
	x86opnd_t recv = ctx_stack_opnd(ctx, argc);
	mov(cb, REG0, recv);

	// We need to assume that both our current method entry and the super
	// method entry we invoke remain stable
	assume_method_lookup_stable(current_defined_class, me, jit->block);
	assume_method_lookup_stable(comptime_superclass, cme, jit->block);

	// Method calls may corrupt types
	ctx_clear_local_types(ctx);

	switch (cme->def->type) {
	case VM_METHOD_TYPE_ISEQ:
	return gen_send_iseq(jit, ctx, ci, cme, block, argc);
	case VM_METHOD_TYPE_CFUNC:
	return gen_send_cfunc(jit, ctx, ci, cme, block, argc, NULL);
	default:
	break;
	}

	RUBY_ASSERT_ALWAYS(false);
	}

	static codegen_status_t
	gen_leave(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Only the return value should be on the stack
	RUBY_ASSERT(ctx->stack_size == 1);

	// Create a size-exit to fall back to the interpreter
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	// Load environment pointer EP from CFP
	mov(cb, REG1, member_opnd(REG_CFP, rb_control_frame_t, ep));

	// Check for interrupts
	ADD_COMMENT(cb, "check for interrupts");
	yjit_check_ints(cb, COUNTED_EXIT(side_exit, leave_se_interrupt));

	// Load the return value
	mov(cb, REG0, ctx_stack_pop(ctx, 1));

	// Pop the current frame (ec->cfp++)
	// Note: the return PC is already in the previous CFP
	add(cb, REG_CFP, imm_opnd(sizeof(rb_control_frame_t)));
	mov(cb, member_opnd(REG_EC, rb_execution_context_t, cfp), REG_CFP);

	// Reload REG_SP for the caller and write the return value.
	// Top of the stack is REG_SP[0] since the caller has sp_offset=1.
	mov(cb, REG_SP, member_opnd(REG_CFP, rb_control_frame_t, sp));
	mov(cb, mem_opnd(64, REG_SP, 0), REG0);

	// Jump to the JIT return address on the frame that was just popped
	const int32_t offset_to_jit_return = -((int32_t)sizeof(rb_control_frame_t)) + (int32_t)offsetof(rb_control_frame_t, jit_return);
	jmp_rm(cb, mem_opnd(64, REG_CFP, offset_to_jit_return));

	return YJIT_END_BLOCK;
	}

	RUBY_EXTERN rb_serial_t ruby_vm_global_constant_state;

	static codegen_status_t
	gen_getglobal(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	ID gid = jit_get_arg(jit, 0);

	// Save the PC and SP because we might make a Ruby call for warning
	jit_prepare_routine_call(jit, ctx, REG0);

	mov(cb, C_ARG_REGS[0], imm_opnd(gid));

	call_ptr(cb, REG0, (void *)&rb_gvar_get);

	x86opnd_t top = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, top, RAX);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_setglobal(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	ID gid = jit_get_arg(jit, 0);

	// Save the PC and SP because we might make a Ruby call for
	// Kernel#set_trace_var
	jit_prepare_routine_call(jit, ctx, REG0);

	mov(cb, C_ARG_REGS[0], imm_opnd(gid));

	x86opnd_t val = ctx_stack_pop(ctx, 1);

	mov(cb, C_ARG_REGS[1], val);

	call_ptr(cb, REG0, (void *)&rb_gvar_set);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_tostring(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// Save the PC and SP because we might make a Ruby call for
	// Kernel#set_trace_var
	jit_prepare_routine_call(jit, ctx, REG0);

	x86opnd_t str = ctx_stack_pop(ctx, 1);
	x86opnd_t val = ctx_stack_pop(ctx, 1);

	mov(cb, C_ARG_REGS[0], str);
	mov(cb, C_ARG_REGS[1], val);

	call_ptr(cb, REG0, (void *)&rb_obj_as_string_result);

	// Push the return value
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_STRING);
	mov(cb, stack_ret, RAX);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_toregexp(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	rb_num_t opt = jit_get_arg(jit, 0);
	rb_num_t cnt = jit_get_arg(jit, 1);

	// Save the PC and SP because this allocates an object and could
	// raise an exception.
	jit_prepare_routine_call(jit, ctx, REG0);

	x86opnd_t values_ptr = ctx_sp_opnd(ctx, -(sizeof(VALUE) * (uint32_t)cnt));
	ctx_stack_pop(ctx, cnt);

	mov(cb, C_ARG_REGS[0], imm_opnd(0));
	mov(cb, C_ARG_REGS[1], imm_opnd(cnt));
	lea(cb, C_ARG_REGS[2], values_ptr);
	call_ptr(cb, REG0, (void *)&rb_ary_tmp_new_from_values);

	// Save the array so we can clear it later
	push(cb, RAX);
	push(cb, RAX); // Alignment
	mov(cb, C_ARG_REGS[0], RAX);
	mov(cb, C_ARG_REGS[1], imm_opnd(opt));
	call_ptr(cb, REG0, (void *)&rb_reg_new_ary);

	// The actual regex is in RAX now. Pop the temp array from
	// rb_ary_tmp_new_from_values into C arg regs so we can clear it
	pop(cb, REG1); // Alignment
	pop(cb, C_ARG_REGS[0]);

	// The value we want to push on the stack is in RAX right now
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, stack_ret, RAX);

	// Clear the temp array.
	call_ptr(cb, REG0, (void *)&rb_ary_clear);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_getspecial(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// This takes two arguments, key and type
	// key is only used when type == 0
	// A non-zero type determines which type of backref to fetch
	//rb_num_t key = jit_get_arg(jit, 0);
	rb_num_t type = jit_get_arg(jit, 1);

	if (type == 0) {
	// not yet implemented
	return YJIT_CANT_COMPILE;
	}
	else if (type & 0x01) {
	// Fetch a "special" backref based on a char encoded by shifting by 1

	// Can raise if matchdata uninitialized
	jit_prepare_routine_call(jit, ctx, REG0);

	// call rb_backref_get()
	ADD_COMMENT(cb, "rb_backref_get");
	call_ptr(cb, REG0, (void *)rb_backref_get);
	mov(cb, C_ARG_REGS[0], RAX);

	switch (type >> 1) {
	case '&':
	ADD_COMMENT(cb, "rb_reg_last_match");
	call_ptr(cb, REG0, (void *)rb_reg_last_match);
	break;
	case '`':
	ADD_COMMENT(cb, "rb_reg_match_pre");
	call_ptr(cb, REG0, (void *)rb_reg_match_pre);
	break;
	case '\'':
	ADD_COMMENT(cb, "rb_reg_match_post");
	call_ptr(cb, REG0, (void *)rb_reg_match_post);
	break;
	case '+':
	ADD_COMMENT(cb, "rb_reg_match_last");
	call_ptr(cb, REG0, (void *)rb_reg_match_last);
	break;
	default:
	rb_bug("invalid back-ref");
	}

	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, stack_ret, RAX);

	return YJIT_KEEP_COMPILING;
	}
	else {
	// Fetch the N-th match from the last backref based on type shifted by 1

	// Can raise if matchdata uninitialized
	jit_prepare_routine_call(jit, ctx, REG0);

	// call rb_backref_get()
	ADD_COMMENT(cb, "rb_backref_get");
	call_ptr(cb, REG0, (void *)rb_backref_get);

	// rb_reg_nth_match((int)(type >> 1), backref);
	ADD_COMMENT(cb, "rb_reg_nth_match");
	mov(cb, C_ARG_REGS[0], imm_opnd(type >> 1));
	mov(cb, C_ARG_REGS[1], RAX);
	call_ptr(cb, REG0, (void *)rb_reg_nth_match);

	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, stack_ret, RAX);

	return YJIT_KEEP_COMPILING;
	}
	}

	VALUE
	rb_vm_getclassvariable(const rb_iseq_t iseq, const rb_cref_t cref, const rb_control_frame_t *cfp, ID id, ICVARC ic);

	rb_cref_t *
	rb_vm_get_cref(const VALUE *ep);

	static codegen_status_t
	gen_getclassvariable(jitstate_t* jit, ctx_t* ctx, codeblock_t* cb)
	{
	// rb_vm_getclassvariable can raise exceptions.
	jit_prepare_routine_call(jit, ctx, REG0);

	mov(cb, C_ARG_REGS[0], member_opnd(REG_CFP, rb_control_frame_t, ep));
	call_ptr(cb, REG0, (void *)rb_vm_get_cref);

	mov(cb, C_ARG_REGS[0], member_opnd(REG_CFP, rb_control_frame_t, iseq));
	mov(cb, C_ARG_REGS[1], RAX);
	mov(cb, C_ARG_REGS[2], REG_CFP);
	mov(cb, C_ARG_REGS[3], imm_opnd(jit_get_arg(jit, 0)));
	mov(cb, C_ARG_REGS[4], imm_opnd(jit_get_arg(jit, 1)));

	call_ptr(cb, REG0, (void *)rb_vm_getclassvariable);

	x86opnd_t stack_top = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, stack_top, RAX);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_opt_getinlinecache(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	VALUE jump_offset = jit_get_arg(jit, 0);
	VALUE const_cache_as_value = jit_get_arg(jit, 1);
	IC ic = (IC)const_cache_as_value;

	// See vm_ic_hit_p(). The same conditions are checked in yjit_constant_ic_update().
	struct iseq_inline_constant_cache_entry *ice = ic->entry;
	if (!ice \|\| // cache not filled
	ice->ic_serial != ruby_vm_global_constant_state /* cache out of date */) {
	// In these cases, leave a block that unconditionally side exits
	// for the interpreter to invalidate.
	return YJIT_CANT_COMPILE;
	}

	if (ice->ic_cref) {
	// Cache is keyed on a certain lexical scope. Use the interpreter's cache.
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	// Call function to verify the cache. It doesn't allocate or call methods.
	bool rb_vm_ic_hit_p(IC ic, const VALUE *reg_ep);
	mov(cb, C_ARG_REGS[0], const_ptr_opnd((void *)ic));
	mov(cb, C_ARG_REGS[1], member_opnd(REG_CFP, rb_control_frame_t, ep));
	call_ptr(cb, REG0, (void *)rb_vm_ic_hit_p);

	// Check the result. _Bool is one byte in SysV.
	test(cb, AL, AL);
	jz_ptr(cb, COUNTED_EXIT(side_exit, opt_getinlinecache_miss));

	// Push ic->entry->value
	mov(cb, REG0, const_ptr_opnd((void *)ic));
	mov(cb, REG0, member_opnd(REG0, struct iseq_inline_constant_cache, entry));
	x86opnd_t stack_top = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, REG0, member_opnd(REG0, struct iseq_inline_constant_cache_entry, value));
	mov(cb, stack_top, REG0);
	}
	else {
	// Optimize for single ractor mode.
	// FIXME: This leaks when st_insert raises NoMemoryError
	if (!assume_single_ractor_mode(jit->block)) return YJIT_CANT_COMPILE;

	// Invalidate output code on any and all constant writes
	// FIXME: This leaks when st_insert raises NoMemoryError
	assume_stable_global_constant_state(jit->block);

	val_type_t type = yjit_type_of_value(ice->value);
	x86opnd_t stack_top = ctx_stack_push(ctx, type);
	jit_mov_gc_ptr(jit, cb, REG0, ice->value);
	mov(cb, stack_top, REG0);
	}

	// Jump over the code for filling the cache
	uint32_t jump_idx = jit_next_insn_idx(jit) + (int32_t)jump_offset;
	gen_direct_jump(
	jit,
	ctx,
	(blockid_t){ .iseq = jit->iseq, .idx = jump_idx }
	);

	return YJIT_END_BLOCK;
	}

	// Push the explict block parameter onto the temporary stack. Part of the
	// interpreter's scheme for avoiding Proc allocations when delegating
	// explict block parameters.
	static codegen_status_t
	gen_getblockparamproxy(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	// A mirror of the interpreter code. Checking for the case
	// where it's pushing rb_block_param_proxy.
	uint8_t *side_exit = yjit_side_exit(jit, ctx);

	// EP level
	uint32_t level = (uint32_t)jit_get_arg(jit, 1);

	// Load environment pointer EP from CFP
	gen_get_ep(cb, REG0, level);

	// Bail when VM_ENV_FLAGS(ep, VM_FRAME_FLAG_MODIFIED_BLOCK_PARAM) is non zero
	test(cb, mem_opnd(64, REG0, SIZEOF_VALUE * VM_ENV_DATA_INDEX_FLAGS), imm_opnd(VM_FRAME_FLAG_MODIFIED_BLOCK_PARAM));
	jnz_ptr(cb, COUNTED_EXIT(side_exit, gbpp_block_param_modified));

	// Load the block handler for the current frame
	// note, VM_ASSERT(VM_ENV_LOCAL_P(ep))
	mov(cb, REG0, mem_opnd(64, REG0, SIZEOF_VALUE * VM_ENV_DATA_INDEX_SPECVAL));

	// Block handler is a tagged pointer. Look at the tag. 0x03 is from VM_BH_ISEQ_BLOCK_P().
	and(cb, REG0_8, imm_opnd(0x3));

	// Bail unless VM_BH_ISEQ_BLOCK_P(bh). This also checks for null.
	cmp(cb, REG0_8, imm_opnd(0x1));
	jnz_ptr(cb, COUNTED_EXIT(side_exit, gbpp_block_handler_not_iseq));

	// Push rb_block_param_proxy. It's a root, so no need to use jit_mov_gc_ptr.
	mov(cb, REG0, const_ptr_opnd((void *)rb_block_param_proxy));
	RUBY_ASSERT(!SPECIAL_CONST_P(rb_block_param_proxy));
	x86opnd_t top = ctx_stack_push(ctx, TYPE_HEAP);
	mov(cb, top, REG0);

	return YJIT_KEEP_COMPILING;
	}

	static codegen_status_t
	gen_invokebuiltin(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	const struct rb_builtin_function bf = (struct rb_builtin_function )jit_get_arg(jit, 0);

	// ec, self, and arguments
	if (bf->argc + 2 > NUM_C_ARG_REGS) {
	return YJIT_CANT_COMPILE;
	}

	// If the calls don't allocate, do they need up to date PC, SP?
	jit_prepare_routine_call(jit, ctx, REG0);

	// Call the builtin func (ec, recv, arg1, arg2, ...)
	mov(cb, C_ARG_REGS[0], REG_EC);
	mov(cb, C_ARG_REGS[1], member_opnd(REG_CFP, rb_control_frame_t, self));

	// Copy arguments from locals
	for (int32_t i = 0; i < bf->argc; i++) {
	x86opnd_t stack_opnd = ctx_stack_opnd(ctx, bf->argc - i - 1);
	x86opnd_t c_arg_reg = C_ARG_REGS[2 + i];
	mov(cb, c_arg_reg, stack_opnd);
	}

	call_ptr(cb, REG0, (void *)bf->func_ptr);

	// Push the return value
	ctx_stack_pop(ctx, bf->argc);
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, stack_ret, RAX);

	return YJIT_KEEP_COMPILING;
	}

	// opt_invokebuiltin_delegate calls a builtin function, like
	// invokebuiltin does, but instead of taking arguments from the top of the
	// stack uses the argument locals (and self) from the current method.
	static codegen_status_t
	gen_opt_invokebuiltin_delegate(jitstate_t jit, ctx_t ctx, codeblock_t *cb)
	{
	const struct rb_builtin_function bf = (struct rb_builtin_function )jit_get_arg(jit, 0);
	int32_t start_index = (int32_t)jit_get_arg(jit, 1);

	// ec, self, and arguments
	if (bf->argc + 2 > NUM_C_ARG_REGS) {
	return YJIT_CANT_COMPILE;
	}

	// If the calls don't allocate, do they need up to date PC, SP?
	jit_prepare_routine_call(jit, ctx, REG0);

	if (bf->argc > 0) {
	// Load environment pointer EP from CFP
	mov(cb, REG0, member_opnd(REG_CFP, rb_control_frame_t, ep));
	}

	// Call the builtin func (ec, recv, arg1, arg2, ...)
	mov(cb, C_ARG_REGS[0], REG_EC);
	mov(cb, C_ARG_REGS[1], member_opnd(REG_CFP, rb_control_frame_t, self));

	// Copy arguments from locals
	for (int32_t i = 0; i < bf->argc; i++) {
	const int32_t offs = -jit->iseq->body->local_table_size - VM_ENV_DATA_SIZE + 1 + start_index + i;
	x86opnd_t local_opnd = mem_opnd(64, REG0, offs * SIZEOF_VALUE);
	x86opnd_t c_arg_reg = C_ARG_REGS[i + 2];
	mov(cb, c_arg_reg, local_opnd);
	}
	call_ptr(cb, REG0, (void *)bf->func_ptr);

	// Push the return value
	x86opnd_t stack_ret = ctx_stack_push(ctx, TYPE_UNKNOWN);
	mov(cb, stack_ret, RAX);

	return YJIT_KEEP_COMPILING;
	}

	static int tracing_invalidate_all_i(void vstart, void vend, size_t stride, void *data);
	static void invalidate_all_blocks_for_tracing(const rb_iseq_t *iseq);

	// Invalidate all generated code and patch C method return code to contain
	// logic for firing the c_return TracePoint event. Once rb_vm_barrier()
	// returns, all other ractors are pausing inside RB_VM_LOCK_ENTER(), which
	// means they are inside a C routine. If there are any generated code on-stack,
	// they are waiting for a return from a C routine. For every routine call, we
	// patch in an exit after the body of the containing VM instruction. This makes
	// it so all the invalidated code exit as soon as execution logically reaches
	// the next VM instruction. The interpreter takes care of firing the tracing
	// event if it so happens that the next VM instruction has one attached.
	//
	// The c_return event needs special handling as our codegen never outputs code
	// that contains tracing logic. If we let the normal output code run until the
	// start of the next VM instruction by relying on the patching scheme above, we
	// would fail to fire the c_return event. The interpreter doesn't fire the
	// event at an instruction boundary, so simply exiting to the interpreter isn't
	// enough. To handle it, we patch in the full logic at the return address. See
	// full_cfunc_return().
	//
	// In addition to patching, we prevent future entries into invalidated code by
	// removing all live blocks from their iseq.
	void
	rb_yjit_tracing_invalidate_all(void)
	{
	if (!rb_yjit_enabled_p()) return;

	// Stop other ractors since we are going to patch machine code.
	RB_VM_LOCK_ENTER();
	rb_vm_barrier();

	// Make it so all live block versions are no longer valid branch targets
	rb_objspace_each_objects(tracing_invalidate_all_i, NULL);

	// Apply patches
	const uint32_t old_pos = cb->write_pos;
	rb_darray_for(global_inval_patches, patch_idx) {
	struct codepage_patch patch = rb_darray_get(global_inval_patches, patch_idx);
	cb_set_pos(cb, patch.inline_patch_pos);
	uint8_t *jump_target = cb_get_ptr(ocb, patch.outlined_target_pos);
	jmp_ptr(cb, jump_target);
	}
	cb_set_pos(cb, old_pos);

	// Freeze invalidated part of the codepage. We only want to wait for
	// running instances of the code to exit from now on, so we shouldn't
	// change the code. There could be other ractors sleeping in
	// branch_stub_hit(), for example. We could harden this by changing memory
	// protection on the frozen range.
	RUBY_ASSERT_ALWAYS(yjit_codepage_frozen_bytes <= old_pos && "frozen bytes should increase monotonically");
	yjit_codepage_frozen_bytes = old_pos;

	RB_VM_LOCK_LEAVE();
	}

	static int
	tracing_invalidate_all_i(void vstart, void vend, size_t stride, void *data)
	{
	VALUE v = (VALUE)vstart;
	for (; v != (VALUE)vend; v += stride) {
	void *ptr = asan_poisoned_object_p(v);
	asan_unpoison_object(v, false);

	if (rb_obj_is_iseq(v)) {
	rb_iseq_t iseq = (rb_iseq_t )v;
	invalidate_all_blocks_for_tracing(iseq);
	}

	asan_poison_object_if(ptr, v);
	}
	return 0;
	}

	static void
	invalidate_all_blocks_for_tracing(const rb_iseq_t *iseq)
	{
	struct rb_iseq_constant_body *body = iseq->body;
	if (!body) return; // iseq yet to be initialized

	ASSERT_vm_locking();

	// Empty all blocks on the iseq so we don't compile new blocks that jump to the
	// invalidted region.
	// TODO Leaking the blocks for now since we might have situations where
	// a different ractor is waiting in branch_stub_hit(). If we free the block
	// that ractor can wake up with a dangling block.
	rb_darray_for(body->yjit_blocks, version_array_idx) {
	rb_yjit_block_array_t version_array = rb_darray_get(body->yjit_blocks, version_array_idx);
	rb_darray_for(version_array, version_idx) {
	// Stop listening for invalidation events like basic operation redefinition.
	block_t *block = rb_darray_get(version_array, version_idx);
	yjit_unlink_method_lookup_dependency(block);
	yjit_block_assumptions_free(block);
	}
	rb_darray_free(version_array);
	}
	rb_darray_free(body->yjit_blocks);
	body->yjit_blocks = NULL;

	#if USE_MJIT
	// Reset output code entry point
	body->jit_func = NULL;
	#endif
	}

	static void
	yjit_reg_op(int opcode, codegen_fn gen_fn)
	{
	RUBY_ASSERT(opcode >= 0 && opcode < VM_INSTRUCTION_SIZE);
	// Check that the op wasn't previously registered
	RUBY_ASSERT(gen_fns[opcode] == NULL);

	gen_fns[opcode] = gen_fn;
	}

	void
	yjit_init_codegen(void)
	{
	// Initialize the code blocks
	uint32_t mem_size = rb_yjit_opts.exec_mem_size * 1024 * 1024;
	uint8_t *mem_block = alloc_exec_mem(mem_size);

	cb = &block;
	cb_init(cb, mem_block, mem_size/2);

	ocb = &outline_block;
	cb_init(ocb, mem_block + mem_size/2, mem_size/2);

	// Generate the interpreter exit code for leave
	leave_exit_code = yjit_gen_leave_exit(cb);

	// Generate full exit code for C func
	gen_full_cfunc_return();

	// Map YARV opcodes to the corresponding codegen functions
	yjit_reg_op(BIN(nop), gen_nop);
	yjit_reg_op(BIN(dup), gen_dup);
	yjit_reg_op(BIN(dupn), gen_dupn);
	yjit_reg_op(BIN(swap), gen_swap);
	yjit_reg_op(BIN(setn), gen_setn);
	yjit_reg_op(BIN(topn), gen_topn);
	yjit_reg_op(BIN(pop), gen_pop);
	yjit_reg_op(BIN(adjuststack), gen_adjuststack);
	yjit_reg_op(BIN(newarray), gen_newarray);
	yjit_reg_op(BIN(duparray), gen_duparray);
	yjit_reg_op(BIN(splatarray), gen_splatarray);
	yjit_reg_op(BIN(expandarray), gen_expandarray);
	yjit_reg_op(BIN(newhash), gen_newhash);
	yjit_reg_op(BIN(newrange), gen_newrange);
	yjit_reg_op(BIN(concatstrings), gen_concatstrings);
	yjit_reg_op(BIN(putnil), gen_putnil);
	yjit_reg_op(BIN(putobject), gen_putobject);
	yjit_reg_op(BIN(putstring), gen_putstring);
	yjit_reg_op(BIN(putobject_INT2FIX_0_), gen_putobject_int2fix);
	yjit_reg_op(BIN(putobject_INT2FIX_1_), gen_putobject_int2fix);
	yjit_reg_op(BIN(putself), gen_putself);
	yjit_reg_op(BIN(putspecialobject), gen_putspecialobject);
	yjit_reg_op(BIN(getlocal), gen_getlocal);
	yjit_reg_op(BIN(getlocal_WC_0), gen_getlocal_wc0);
	yjit_reg_op(BIN(getlocal_WC_1), gen_getlocal_wc1);
	yjit_reg_op(BIN(setlocal), gen_setlocal);
	yjit_reg_op(BIN(setlocal_WC_0), gen_setlocal_wc0);
	yjit_reg_op(BIN(setlocal_WC_1), gen_setlocal_wc1);
	yjit_reg_op(BIN(getinstancevariable), gen_getinstancevariable);
	yjit_reg_op(BIN(setinstancevariable), gen_setinstancevariable);
	yjit_reg_op(BIN(defined), gen_defined);
	yjit_reg_op(BIN(checktype), gen_checktype);
	yjit_reg_op(BIN(opt_lt), gen_opt_lt);
	yjit_reg_op(BIN(opt_le), gen_opt_le);
	yjit_reg_op(BIN(opt_ge), gen_opt_ge);
	yjit_reg_op(BIN(opt_gt), gen_opt_gt);
	yjit_reg_op(BIN(opt_eq), gen_opt_eq);
	yjit_reg_op(BIN(opt_neq), gen_opt_neq);
	yjit_reg_op(BIN(opt_aref), gen_opt_aref);
	yjit_reg_op(BIN(opt_aset), gen_opt_aset);
	yjit_reg_op(BIN(opt_and), gen_opt_and);
	yjit_reg_op(BIN(opt_or), gen_opt_or);
	yjit_reg_op(BIN(opt_minus), gen_opt_minus);
	yjit_reg_op(BIN(opt_plus), gen_opt_plus);
	yjit_reg_op(BIN(opt_mult), gen_opt_mult);
	yjit_reg_op(BIN(opt_div), gen_opt_div);
	yjit_reg_op(BIN(opt_mod), gen_opt_mod);
	yjit_reg_op(BIN(opt_ltlt), gen_opt_ltlt);
	yjit_reg_op(BIN(opt_nil_p), gen_opt_nil_p);
	yjit_reg_op(BIN(opt_empty_p), gen_opt_empty_p);
	yjit_reg_op(BIN(opt_str_freeze), gen_opt_str_freeze);
	yjit_reg_op(BIN(opt_str_uminus), gen_opt_str_uminus);
	yjit_reg_op(BIN(opt_not), gen_opt_not);
	yjit_reg_op(BIN(opt_size), gen_opt_size);
	yjit_reg_op(BIN(opt_length), gen_opt_length);
	yjit_reg_op(BIN(opt_regexpmatch2), gen_opt_regexpmatch2);
	yjit_reg_op(BIN(opt_getinlinecache), gen_opt_getinlinecache);
	yjit_reg_op(BIN(invokebuiltin), gen_invokebuiltin);
	yjit_reg_op(BIN(opt_invokebuiltin_delegate), gen_opt_invokebuiltin_delegate);
	yjit_reg_op(BIN(opt_invokebuiltin_delegate_leave), gen_opt_invokebuiltin_delegate);
	yjit_reg_op(BIN(opt_case_dispatch), gen_opt_case_dispatch);
	yjit_reg_op(BIN(branchif), gen_branchif);
	yjit_reg_op(BIN(branchunless), gen_branchunless);
	yjit_reg_op(BIN(branchnil), gen_branchnil);
	yjit_reg_op(BIN(jump), gen_jump);
	yjit_reg_op(BIN(getblockparamproxy), gen_getblockparamproxy);
	yjit_reg_op(BIN(opt_send_without_block), gen_opt_send_without_block);
	yjit_reg_op(BIN(send), gen_send);
	yjit_reg_op(BIN(invokesuper), gen_invokesuper);
	yjit_reg_op(BIN(leave), gen_leave);
	yjit_reg_op(BIN(getglobal), gen_getglobal);
	yjit_reg_op(BIN(setglobal), gen_setglobal);
	yjit_reg_op(BIN(tostring), gen_tostring);
	yjit_reg_op(BIN(toregexp), gen_toregexp);
	yjit_reg_op(BIN(getspecial), gen_getspecial);
	yjit_reg_op(BIN(getclassvariable), gen_getclassvariable);

	yjit_method_codegen_table = st_init_numtable();

	// Specialization for C methods. See yjit_reg_method() for details.
	yjit_reg_method(rb_cBasicObject, "!", jit_rb_obj_not);

	yjit_reg_method(rb_cNilClass, "nil?", jit_rb_true);
	yjit_reg_method(rb_mKernel, "nil?", jit_rb_false);

	yjit_reg_method(rb_cBasicObject, "==", jit_rb_obj_equal);
	yjit_reg_method(rb_cBasicObject, "equal?", jit_rb_obj_equal);
	yjit_reg_method(rb_mKernel, "eql?", jit_rb_obj_equal);
	yjit_reg_method(rb_cModule, "==", jit_rb_obj_equal);
	yjit_reg_method(rb_cSymbol, "==", jit_rb_obj_equal);
	yjit_reg_method(rb_cSymbol, "===", jit_rb_obj_equal);

	// rb_str_to_s() methods in string.c
	yjit_reg_method(rb_cString, "to_s", jit_rb_str_to_s);
	yjit_reg_method(rb_cString, "to_str", jit_rb_str_to_s);
	yjit_reg_method(rb_cString, "bytesize", jit_rb_str_bytesize);

	// Thread.current
	yjit_reg_method(rb_singleton_class(rb_cThread), "current", jit_thread_s_current);
	}

ruby / ruby Public

ruby/yjit_codegen.c