src/compiler/codegen/x86/call_x86.cc - platform/art - Git at Google

 /*
  * Copyright (C) 2012 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 /* This file contains codegen for the X86 ISA */

 #include "x86_lir.h"
 #include "codegen_x86.h"
 #include "../codegen_util.h"
 #include "../ralloc_util.h"

 namespace art {

 void X86Codegen::GenSpecialCase(CompilationUnit* cu, BasicBlock* bb, MIR* mir,
                                 SpecialCaseHandler special_case)
 {
   // TODO
 }

 /*
  * The sparse table in the literal pool is an array of <key,displacement>
  * pairs.
  */
 void X86Codegen::GenSparseSwitch(CompilationUnit* cu, uint32_t table_offset, RegLocation rl_src)
 {
   const uint16_t* table = cu->insns + cu->current_dalvik_offset + table_offset;
   if (cu->verbose) {
     DumpSparseSwitchTable(table);
   }
   int entries = table[1];
   const int* keys = reinterpret_cast<const int*>(&table[2]);
   const int* targets = &keys[entries];
   rl_src = LoadValue(cu, rl_src, kCoreReg);
   for (int i = 0; i < entries; i++) {
     int key = keys[i];
     BasicBlock* case_block = FindBlock(cu, cu->current_dalvik_offset + targets[i]);
     LIR* label_list = cu->block_label_list;
     OpCmpImmBranch(cu, kCondEq, rl_src.low_reg, key,
                    &label_list[case_block->id]);
   }
 }

 /*
  * Code pattern will look something like:
  *
  * mov  r_val, ..
  * call 0
  * pop  r_start_of_method
  * sub  r_start_of_method, ..
  * mov  r_key_reg, r_val
  * sub  r_key_reg, low_key
  * cmp  r_key_reg, size-1  ; bound check
  * ja   done
  * mov  r_disp, [r_start_of_method + r_key_reg * 4 + table_offset]
  * add  r_start_of_method, r_disp
  * jmp  r_start_of_method
  * done:
  */
 void X86Codegen::GenPackedSwitch(CompilationUnit* cu, uint32_t table_offset, RegLocation rl_src)
 {
   const uint16_t* table = cu->insns + cu->current_dalvik_offset + table_offset;
   if (cu->verbose) {
     DumpPackedSwitchTable(table);
   }
   // Add the table to the list - we'll process it later
   SwitchTable *tab_rec =
       static_cast<SwitchTable *>(NewMem(cu, sizeof(SwitchTable), true, kAllocData));
   tab_rec->table = table;
   tab_rec->vaddr = cu->current_dalvik_offset;
   int size = table[1];
   tab_rec->targets = static_cast<LIR**>(NewMem(cu, size * sizeof(LIR*), true, kAllocLIR));
   InsertGrowableList(cu, &cu->switch_tables, reinterpret_cast<uintptr_t>(tab_rec));

   // Get the switch value
   rl_src = LoadValue(cu, rl_src, kCoreReg);
   int start_of_method_reg = AllocTemp(cu);
   // Materialize a pointer to the switch table
   //NewLIR0(cu, kX86Bkpt);
   NewLIR1(cu, kX86StartOfMethod, start_of_method_reg);
   int low_key = s4FromSwitchData(&table[2]);
   int keyReg;
   // Remove the bias, if necessary
   if (low_key == 0) {
     keyReg = rl_src.low_reg;
   } else {
     keyReg = AllocTemp(cu);
     OpRegRegImm(cu, kOpSub, keyReg, rl_src.low_reg, low_key);
   }
   // Bounds check - if < 0 or >= size continue following switch
   OpRegImm(cu, kOpCmp, keyReg, size-1);
   LIR* branch_over = OpCondBranch(cu, kCondHi, NULL);

   // Load the displacement from the switch table
   int disp_reg = AllocTemp(cu);
   NewLIR5(cu, kX86PcRelLoadRA, disp_reg, start_of_method_reg, keyReg, 2,
           reinterpret_cast<uintptr_t>(tab_rec));
   // Add displacement to start of method
   OpRegReg(cu, kOpAdd, start_of_method_reg, disp_reg);
   // ..and go!
   LIR* switch_branch = NewLIR1(cu, kX86JmpR, start_of_method_reg);
   tab_rec->anchor = switch_branch;

   /* branch_over target here */
   LIR* target = NewLIR0(cu, kPseudoTargetLabel);
   branch_over->target = target;
 }

 /*
  * Array data table format:
  *  ushort ident = 0x0300   magic value
  *  ushort width            width of each element in the table
  *  uint   size             number of elements in the table
  *  ubyte  data[size*width] table of data values (may contain a single-byte
  *                          padding at the end)
  *
  * Total size is 4+(width * size + 1)/2 16-bit code units.
  */
 void X86Codegen::GenFillArrayData(CompilationUnit* cu, uint32_t table_offset, RegLocation rl_src)
 {
   const uint16_t* table = cu->insns + cu->current_dalvik_offset + table_offset;
   // Add the table to the list - we'll process it later
   FillArrayData *tab_rec =
       static_cast<FillArrayData*>(NewMem(cu, sizeof(FillArrayData), true, kAllocData));
   tab_rec->table = table;
   tab_rec->vaddr = cu->current_dalvik_offset;
   uint16_t width = tab_rec->table[1];
   uint32_t size = tab_rec->table[2] | ((static_cast<uint32_t>(tab_rec->table[3])) << 16);
   tab_rec->size = (size * width) + 8;

   InsertGrowableList(cu, &cu->fill_array_data, reinterpret_cast<uintptr_t>(tab_rec));

   // Making a call - use explicit registers
   FlushAllRegs(cu);   /* Everything to home location */
   LoadValueDirectFixed(cu, rl_src, rX86_ARG0);
   // Materialize a pointer to the fill data image
   NewLIR1(cu, kX86StartOfMethod, rX86_ARG2);
   NewLIR2(cu, kX86PcRelAdr, rX86_ARG1, reinterpret_cast<uintptr_t>(tab_rec));
   NewLIR2(cu, kX86Add32RR, rX86_ARG1, rX86_ARG2);
   CallRuntimeHelperRegReg(cu, ENTRYPOINT_OFFSET(pHandleFillArrayDataFromCode), rX86_ARG0,
                           rX86_ARG1, true);
 }

 void X86Codegen::GenMonitorEnter(CompilationUnit* cu, int opt_flags, RegLocation rl_src)
 {
   FlushAllRegs(cu);
   LoadValueDirectFixed(cu, rl_src, rCX);  // Get obj
   LockCallTemps(cu);  // Prepare for explicit register usage
   GenNullCheck(cu, rl_src.s_reg_low, rCX, opt_flags);
   // If lock is unheld, try to grab it quickly with compare and exchange
   // TODO: copy and clear hash state?
   NewLIR2(cu, kX86Mov32RT, rDX, Thread::ThinLockIdOffset().Int32Value());
   NewLIR2(cu, kX86Sal32RI, rDX, LW_LOCK_OWNER_SHIFT);
   NewLIR2(cu, kX86Xor32RR, rAX, rAX);
   NewLIR3(cu, kX86LockCmpxchgMR, rCX, mirror::Object::MonitorOffset().Int32Value(), rDX);
   LIR* branch = NewLIR2(cu, kX86Jcc8, 0, kX86CondEq);
   // If lock is held, go the expensive route - artLockObjectFromCode(self, obj);
   CallRuntimeHelperReg(cu, ENTRYPOINT_OFFSET(pLockObjectFromCode), rCX, true);
   branch->target = NewLIR0(cu, kPseudoTargetLabel);
 }

 void X86Codegen::GenMonitorExit(CompilationUnit* cu, int opt_flags, RegLocation rl_src)
 {
   FlushAllRegs(cu);
   LoadValueDirectFixed(cu, rl_src, rAX);  // Get obj
   LockCallTemps(cu);  // Prepare for explicit register usage
   GenNullCheck(cu, rl_src.s_reg_low, rAX, opt_flags);
   // If lock is held by the current thread, clear it to quickly release it
   // TODO: clear hash state?
   NewLIR2(cu, kX86Mov32RT, rDX, Thread::ThinLockIdOffset().Int32Value());
   NewLIR2(cu, kX86Sal32RI, rDX, LW_LOCK_OWNER_SHIFT);
   NewLIR3(cu, kX86Mov32RM, rCX, rAX, mirror::Object::MonitorOffset().Int32Value());
   OpRegReg(cu, kOpSub, rCX, rDX);
   LIR* branch = NewLIR2(cu, kX86Jcc8, 0, kX86CondNe);
   NewLIR3(cu, kX86Mov32MR, rAX, mirror::Object::MonitorOffset().Int32Value(), rCX);
   LIR* branch2 = NewLIR1(cu, kX86Jmp8, 0);
   branch->target = NewLIR0(cu, kPseudoTargetLabel);
   // Otherwise, go the expensive route - UnlockObjectFromCode(obj);
   CallRuntimeHelperReg(cu, ENTRYPOINT_OFFSET(pUnlockObjectFromCode), rAX, true);
   branch2->target = NewLIR0(cu, kPseudoTargetLabel);
 }

 void X86Codegen::GenMoveException(CompilationUnit* cu, RegLocation rl_dest)
 {
   int ex_offset = Thread::ExceptionOffset().Int32Value();
   RegLocation rl_result = EvalLoc(cu, rl_dest, kCoreReg, true);
   NewLIR2(cu, kX86Mov32RT, rl_result.low_reg, ex_offset);
   NewLIR2(cu, kX86Mov32TI, ex_offset, 0);
   StoreValue(cu, rl_dest, rl_result);
 }

 /*
  * Mark garbage collection card. Skip if the value we're storing is null.
  */
 void X86Codegen::MarkGCCard(CompilationUnit* cu, int val_reg, int tgt_addr_reg)
 {
   int reg_card_base = AllocTemp(cu);
   int reg_card_no = AllocTemp(cu);
   LIR* branch_over = OpCmpImmBranch(cu, kCondEq, val_reg, 0, NULL);
   NewLIR2(cu, kX86Mov32RT, reg_card_base, Thread::CardTableOffset().Int32Value());
   OpRegRegImm(cu, kOpLsr, reg_card_no, tgt_addr_reg, CardTable::kCardShift);
   StoreBaseIndexed(cu, reg_card_base, reg_card_no, reg_card_base, 0,
                    kUnsignedByte);
   LIR* target = NewLIR0(cu, kPseudoTargetLabel);
   branch_over->target = target;
   FreeTemp(cu, reg_card_base);
   FreeTemp(cu, reg_card_no);
 }

 void X86Codegen::GenEntrySequence(CompilationUnit* cu, RegLocation* ArgLocs, RegLocation rl_method)
 {
   /*
    * On entry, rX86_ARG0, rX86_ARG1, rX86_ARG2 are live.  Let the register
    * allocation mechanism know so it doesn't try to use any of them when
    * expanding the frame or flushing.  This leaves the utility
    * code with no spare temps.
    */
   LockTemp(cu, rX86_ARG0);
   LockTemp(cu, rX86_ARG1);
   LockTemp(cu, rX86_ARG2);

   /* Build frame, return address already on stack */
   OpRegImm(cu, kOpSub, rX86_SP, cu->frame_size - 4);

   /*
    * We can safely skip the stack overflow check if we're
    * a leaf *and* our frame size < fudge factor.
    */
   bool skip_overflow_check = ((cu->attrs & METHOD_IS_LEAF) &&
                 (static_cast<size_t>(cu->frame_size) <
                 Thread::kStackOverflowReservedBytes));
   NewLIR0(cu, kPseudoMethodEntry);
   /* Spill core callee saves */
   SpillCoreRegs(cu);
   /* NOTE: promotion of FP regs currently unsupported, thus no FP spill */
   DCHECK_EQ(cu->num_fp_spills, 0);
   if (!skip_overflow_check) {
     // cmp rX86_SP, fs:[stack_end_]; jcc throw_launchpad
     LIR* tgt = RawLIR(cu, 0, kPseudoThrowTarget, kThrowStackOverflow, 0, 0, 0, 0);
     OpRegThreadMem(cu, kOpCmp, rX86_SP, Thread::StackEndOffset().Int32Value());
     OpCondBranch(cu, kCondUlt, tgt);
     // Remember branch target - will process later
     InsertGrowableList(cu, &cu->throw_launchpads, reinterpret_cast<uintptr_t>(tgt));
   }

   FlushIns(cu, ArgLocs, rl_method);

   FreeTemp(cu, rX86_ARG0);
   FreeTemp(cu, rX86_ARG1);
   FreeTemp(cu, rX86_ARG2);
 }

 void X86Codegen::GenExitSequence(CompilationUnit* cu) {
   /*
    * In the exit path, rX86_RET0/rX86_RET1 are live - make sure they aren't
    * allocated by the register utilities as temps.
    */
   LockTemp(cu, rX86_RET0);
   LockTemp(cu, rX86_RET1);

   NewLIR0(cu, kPseudoMethodExit);
   UnSpillCoreRegs(cu);
   /* Remove frame except for return address */
   OpRegImm(cu, kOpAdd, rX86_SP, cu->frame_size - 4);
   NewLIR0(cu, kX86Ret);
 }

 }  // namespace art
	/*
	* Copyright (C) 2012 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	/* This file contains codegen for the X86 ISA */

	#include "x86_lir.h"
	#include "codegen_x86.h"
	#include "../codegen_util.h"
	#include "../ralloc_util.h"

	namespace art {

	void X86Codegen::GenSpecialCase(CompilationUnit* cu, BasicBlock* bb, MIR* mir,
	SpecialCaseHandler special_case)
	{
	// TODO
	}

	/*
	* The sparse table in the literal pool is an array of <key,displacement>
	* pairs.
	*/
	void X86Codegen::GenSparseSwitch(CompilationUnit* cu, uint32_t table_offset, RegLocation rl_src)
	{
	const uint16_t* table = cu->insns + cu->current_dalvik_offset + table_offset;
	if (cu->verbose) {
	DumpSparseSwitchTable(table);
	}
	int entries = table[1];
	const int* keys = reinterpret_cast<const int*>(&table[2]);
	const int* targets = &keys[entries];
	rl_src = LoadValue(cu, rl_src, kCoreReg);
	for (int i = 0; i < entries; i++) {
	int key = keys[i];
	BasicBlock* case_block = FindBlock(cu, cu->current_dalvik_offset + targets[i]);
	LIR* label_list = cu->block_label_list;
	OpCmpImmBranch(cu, kCondEq, rl_src.low_reg, key,
	&label_list[case_block->id]);
	}
	}

	/*
	* Code pattern will look something like:
	*
	* mov r_val, ..
	* call 0
	* pop r_start_of_method
	* sub r_start_of_method, ..
	* mov r_key_reg, r_val
	* sub r_key_reg, low_key
	* cmp r_key_reg, size-1 ; bound check
	* ja done
	* mov r_disp, [r_start_of_method + r_key_reg * 4 + table_offset]
	* add r_start_of_method, r_disp
	* jmp r_start_of_method
	* done:
	*/
	void X86Codegen::GenPackedSwitch(CompilationUnit* cu, uint32_t table_offset, RegLocation rl_src)
	{
	const uint16_t* table = cu->insns + cu->current_dalvik_offset + table_offset;
	if (cu->verbose) {
	DumpPackedSwitchTable(table);
	}
	// Add the table to the list - we'll process it later
	SwitchTable *tab_rec =
	static_cast<SwitchTable *>(NewMem(cu, sizeof(SwitchTable), true, kAllocData));
	tab_rec->table = table;
	tab_rec->vaddr = cu->current_dalvik_offset;
	int size = table[1];
	tab_rec->targets = static_cast<LIR*>(NewMem(cu, size sizeof(LIR*), true, kAllocLIR));
	InsertGrowableList(cu, &cu->switch_tables, reinterpret_cast<uintptr_t>(tab_rec));

	// Get the switch value
	rl_src = LoadValue(cu, rl_src, kCoreReg);
	int start_of_method_reg = AllocTemp(cu);
	// Materialize a pointer to the switch table
	//NewLIR0(cu, kX86Bkpt);
	NewLIR1(cu, kX86StartOfMethod, start_of_method_reg);
	int low_key = s4FromSwitchData(&table[2]);
	int keyReg;
	// Remove the bias, if necessary
	if (low_key == 0) {
	keyReg = rl_src.low_reg;
	} else {
	keyReg = AllocTemp(cu);
	OpRegRegImm(cu, kOpSub, keyReg, rl_src.low_reg, low_key);
	}
	// Bounds check - if < 0 or >= size continue following switch
	OpRegImm(cu, kOpCmp, keyReg, size-1);
	LIR* branch_over = OpCondBranch(cu, kCondHi, NULL);

	// Load the displacement from the switch table
	int disp_reg = AllocTemp(cu);
	NewLIR5(cu, kX86PcRelLoadRA, disp_reg, start_of_method_reg, keyReg, 2,
	reinterpret_cast<uintptr_t>(tab_rec));
	// Add displacement to start of method
	OpRegReg(cu, kOpAdd, start_of_method_reg, disp_reg);
	// ..and go!
	LIR* switch_branch = NewLIR1(cu, kX86JmpR, start_of_method_reg);
	tab_rec->anchor = switch_branch;

	/* branch_over target here */
	LIR* target = NewLIR0(cu, kPseudoTargetLabel);
	branch_over->target = target;
	}

	/*
	* Array data table format:
	* ushort ident = 0x0300 magic value
	* ushort width width of each element in the table
	* uint size number of elements in the table
	* ubyte data[size*width] table of data values (may contain a single-byte
	* padding at the end)
	*
	* Total size is 4+(width * size + 1)/2 16-bit code units.
	*/
	void X86Codegen::GenFillArrayData(CompilationUnit* cu, uint32_t table_offset, RegLocation rl_src)
	{
	const uint16_t* table = cu->insns + cu->current_dalvik_offset + table_offset;
	// Add the table to the list - we'll process it later
	FillArrayData *tab_rec =
	static_cast<FillArrayData*>(NewMem(cu, sizeof(FillArrayData), true, kAllocData));
	tab_rec->table = table;
	tab_rec->vaddr = cu->current_dalvik_offset;
	uint16_t width = tab_rec->table[1];
	uint32_t size = tab_rec->table[2] \| ((static_cast<uint32_t>(tab_rec->table[3])) << 16);
	tab_rec->size = (size * width) + 8;

	InsertGrowableList(cu, &cu->fill_array_data, reinterpret_cast<uintptr_t>(tab_rec));

	// Making a call - use explicit registers
	FlushAllRegs(cu); /* Everything to home location */
	LoadValueDirectFixed(cu, rl_src, rX86_ARG0);
	// Materialize a pointer to the fill data image
	NewLIR1(cu, kX86StartOfMethod, rX86_ARG2);
	NewLIR2(cu, kX86PcRelAdr, rX86_ARG1, reinterpret_cast<uintptr_t>(tab_rec));
	NewLIR2(cu, kX86Add32RR, rX86_ARG1, rX86_ARG2);
	CallRuntimeHelperRegReg(cu, ENTRYPOINT_OFFSET(pHandleFillArrayDataFromCode), rX86_ARG0,
	rX86_ARG1, true);
	}

	void X86Codegen::GenMonitorEnter(CompilationUnit* cu, int opt_flags, RegLocation rl_src)
	{
	FlushAllRegs(cu);
	LoadValueDirectFixed(cu, rl_src, rCX); // Get obj
	LockCallTemps(cu); // Prepare for explicit register usage
	GenNullCheck(cu, rl_src.s_reg_low, rCX, opt_flags);
	// If lock is unheld, try to grab it quickly with compare and exchange
	// TODO: copy and clear hash state?
	NewLIR2(cu, kX86Mov32RT, rDX, Thread::ThinLockIdOffset().Int32Value());
	NewLIR2(cu, kX86Sal32RI, rDX, LW_LOCK_OWNER_SHIFT);
	NewLIR2(cu, kX86Xor32RR, rAX, rAX);
	NewLIR3(cu, kX86LockCmpxchgMR, rCX, mirror::Object::MonitorOffset().Int32Value(), rDX);
	LIR* branch = NewLIR2(cu, kX86Jcc8, 0, kX86CondEq);
	// If lock is held, go the expensive route - artLockObjectFromCode(self, obj);
	CallRuntimeHelperReg(cu, ENTRYPOINT_OFFSET(pLockObjectFromCode), rCX, true);
	branch->target = NewLIR0(cu, kPseudoTargetLabel);
	}

	void X86Codegen::GenMonitorExit(CompilationUnit* cu, int opt_flags, RegLocation rl_src)
	{
	FlushAllRegs(cu);
	LoadValueDirectFixed(cu, rl_src, rAX); // Get obj
	LockCallTemps(cu); // Prepare for explicit register usage
	GenNullCheck(cu, rl_src.s_reg_low, rAX, opt_flags);
	// If lock is held by the current thread, clear it to quickly release it
	// TODO: clear hash state?
	NewLIR2(cu, kX86Mov32RT, rDX, Thread::ThinLockIdOffset().Int32Value());
	NewLIR2(cu, kX86Sal32RI, rDX, LW_LOCK_OWNER_SHIFT);
	NewLIR3(cu, kX86Mov32RM, rCX, rAX, mirror::Object::MonitorOffset().Int32Value());
	OpRegReg(cu, kOpSub, rCX, rDX);
	LIR* branch = NewLIR2(cu, kX86Jcc8, 0, kX86CondNe);
	NewLIR3(cu, kX86Mov32MR, rAX, mirror::Object::MonitorOffset().Int32Value(), rCX);
	LIR* branch2 = NewLIR1(cu, kX86Jmp8, 0);
	branch->target = NewLIR0(cu, kPseudoTargetLabel);
	// Otherwise, go the expensive route - UnlockObjectFromCode(obj);
	CallRuntimeHelperReg(cu, ENTRYPOINT_OFFSET(pUnlockObjectFromCode), rAX, true);
	branch2->target = NewLIR0(cu, kPseudoTargetLabel);
	}

	void X86Codegen::GenMoveException(CompilationUnit* cu, RegLocation rl_dest)
	{
	int ex_offset = Thread::ExceptionOffset().Int32Value();
	RegLocation rl_result = EvalLoc(cu, rl_dest, kCoreReg, true);
	NewLIR2(cu, kX86Mov32RT, rl_result.low_reg, ex_offset);
	NewLIR2(cu, kX86Mov32TI, ex_offset, 0);
	StoreValue(cu, rl_dest, rl_result);
	}

	/*
	* Mark garbage collection card. Skip if the value we're storing is null.
	*/
	void X86Codegen::MarkGCCard(CompilationUnit* cu, int val_reg, int tgt_addr_reg)
	{
	int reg_card_base = AllocTemp(cu);
	int reg_card_no = AllocTemp(cu);
	LIR* branch_over = OpCmpImmBranch(cu, kCondEq, val_reg, 0, NULL);
	NewLIR2(cu, kX86Mov32RT, reg_card_base, Thread::CardTableOffset().Int32Value());
	OpRegRegImm(cu, kOpLsr, reg_card_no, tgt_addr_reg, CardTable::kCardShift);
	StoreBaseIndexed(cu, reg_card_base, reg_card_no, reg_card_base, 0,
	kUnsignedByte);
	LIR* target = NewLIR0(cu, kPseudoTargetLabel);
	branch_over->target = target;
	FreeTemp(cu, reg_card_base);
	FreeTemp(cu, reg_card_no);
	}

	void X86Codegen::GenEntrySequence(CompilationUnit* cu, RegLocation* ArgLocs, RegLocation rl_method)
	{
	/*
	* On entry, rX86_ARG0, rX86_ARG1, rX86_ARG2 are live. Let the register
	* allocation mechanism know so it doesn't try to use any of them when
	* expanding the frame or flushing. This leaves the utility
	* code with no spare temps.
	*/
	LockTemp(cu, rX86_ARG0);
	LockTemp(cu, rX86_ARG1);
	LockTemp(cu, rX86_ARG2);

	/* Build frame, return address already on stack */
	OpRegImm(cu, kOpSub, rX86_SP, cu->frame_size - 4);

	/*
	* We can safely skip the stack overflow check if we're
	* a leaf and our frame size < fudge factor.
	*/
	bool skip_overflow_check = ((cu->attrs & METHOD_IS_LEAF) &&
	(static_cast<size_t>(cu->frame_size) <
	Thread::kStackOverflowReservedBytes));
	NewLIR0(cu, kPseudoMethodEntry);
	/* Spill core callee saves */
	SpillCoreRegs(cu);
	/* NOTE: promotion of FP regs currently unsupported, thus no FP spill */
	DCHECK_EQ(cu->num_fp_spills, 0);
	if (!skip_overflow_check) {
	// cmp rX86_SP, fs:[stack_end_]; jcc throw_launchpad
	LIR* tgt = RawLIR(cu, 0, kPseudoThrowTarget, kThrowStackOverflow, 0, 0, 0, 0);
	OpRegThreadMem(cu, kOpCmp, rX86_SP, Thread::StackEndOffset().Int32Value());
	OpCondBranch(cu, kCondUlt, tgt);
	// Remember branch target - will process later
	InsertGrowableList(cu, &cu->throw_launchpads, reinterpret_cast<uintptr_t>(tgt));
	}

	FlushIns(cu, ArgLocs, rl_method);

	FreeTemp(cu, rX86_ARG0);
	FreeTemp(cu, rX86_ARG1);
	FreeTemp(cu, rX86_ARG2);
	}

	void X86Codegen::GenExitSequence(CompilationUnit* cu) {
	/*
	* In the exit path, rX86_RET0/rX86_RET1 are live - make sure they aren't
	* allocated by the register utilities as temps.
	*/
	LockTemp(cu, rX86_RET0);
	LockTemp(cu, rX86_RET1);

	NewLIR0(cu, kPseudoMethodExit);
	UnSpillCoreRegs(cu);
	/* Remove frame except for return address */
	OpRegImm(cu, kOpAdd, rX86_SP, cu->frame_size - 4);
	NewLIR0(cu, kX86Ret);
	}

	} // namespace art