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// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#if V8_TARGET_ARCH_X87
#include "src/debug/debug.h"
#include "src/codegen.h"
#include "src/debug/liveedit.h"
#include "src/x87/frames-x87.h"
namespace v8 {
namespace internal {
#define __ ACCESS_MASM(masm)
void EmitDebugBreakSlot(MacroAssembler* masm) {
Label check_codesize;
__ bind(&check_codesize);
__ Nop(Assembler::kDebugBreakSlotLength);
DCHECK_EQ(Assembler::kDebugBreakSlotLength,
masm->SizeOfCodeGeneratedSince(&check_codesize));
}
void DebugCodegen::GenerateSlot(MacroAssembler* masm, RelocInfo::Mode mode) {
// Generate enough nop's to make space for a call instruction.
masm->RecordDebugBreakSlot(mode);
EmitDebugBreakSlot(masm);
}
void DebugCodegen::ClearDebugBreakSlot(Isolate* isolate, Address pc) {
CodePatcher patcher(isolate, pc, Assembler::kDebugBreakSlotLength);
EmitDebugBreakSlot(patcher.masm());
}
void DebugCodegen::PatchDebugBreakSlot(Isolate* isolate, Address pc,
Handle<Code> code) {
DCHECK(code->is_debug_stub());
static const int kSize = Assembler::kDebugBreakSlotLength;
CodePatcher patcher(isolate, pc, kSize);
// Add a label for checking the size of the code used for returning.
Label check_codesize;
patcher.masm()->bind(&check_codesize);
patcher.masm()->call(code->entry(), RelocInfo::NONE32);
// Check that the size of the code generated is as expected.
DCHECK_EQ(kSize, patcher.masm()->SizeOfCodeGeneratedSince(&check_codesize));
}
bool DebugCodegen::DebugBreakSlotIsPatched(Address pc) {
return !Assembler::IsNop(pc);
}
void DebugCodegen::GenerateDebugBreakStub(MacroAssembler* masm,
DebugBreakCallHelperMode mode) {
__ RecordComment("Debug break");
// Enter an internal frame.
{
FrameScope scope(masm, StackFrame::INTERNAL);
// Load padding words on stack.
for (int i = 0; i < LiveEdit::kFramePaddingInitialSize; i++) {
__ push(Immediate(Smi::FromInt(LiveEdit::kFramePaddingValue)));
}
__ push(Immediate(Smi::FromInt(LiveEdit::kFramePaddingInitialSize)));
// Push arguments for DebugBreak call.
if (mode == SAVE_RESULT_REGISTER) {
// Break on return.
__ push(eax);
} else {
// Non-return breaks.
__ Push(masm->isolate()->factory()->the_hole_value());
}
__ Move(eax, Immediate(1));
__ mov(ebx,
Immediate(ExternalReference(
Runtime::FunctionForId(Runtime::kDebugBreak), masm->isolate())));
CEntryStub ceb(masm->isolate(), 1);
__ CallStub(&ceb);
if (FLAG_debug_code) {
for (int i = 0; i < kNumJSCallerSaved; ++i) {
Register reg = {JSCallerSavedCode(i)};
// Do not clobber eax if mode is SAVE_RESULT_REGISTER. It will
// contain return value of the function.
if (!(reg.is(eax) && (mode == SAVE_RESULT_REGISTER))) {
__ Move(reg, Immediate(kDebugZapValue));
}
}
}
__ pop(ebx);
// We divide stored value by 2 (untagging) and multiply it by word's size.
STATIC_ASSERT(kSmiTagSize == 1 && kSmiShiftSize == 0);
__ lea(esp, Operand(esp, ebx, times_half_pointer_size, 0));
// Get rid of the internal frame.
}
// This call did not replace a call , so there will be an unwanted
// return address left on the stack. Here we get rid of that.
__ add(esp, Immediate(kPointerSize));
// Now that the break point has been handled, resume normal execution by
// jumping to the target address intended by the caller and that was
// overwritten by the address of DebugBreakXXX.
ExternalReference after_break_target =
ExternalReference::debug_after_break_target_address(masm->isolate());
__ jmp(Operand::StaticVariable(after_break_target));
}
void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
// We do not know our frame height, but set esp based on ebp.
__ lea(esp, Operand(ebp, FrameDropperFrameConstants::kFunctionOffset));
__ pop(edi); // Function.
__ add(esp, Immediate(-FrameDropperFrameConstants::kCodeOffset)); // INTERNAL
// frame
// marker
// and code
__ pop(ebp);
ParameterCount dummy(0);
__ CheckDebugHook(edi, no_reg, dummy, dummy);
// Load context from the function.
__ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
// Clear new.target register as a safety measure.
__ mov(edx, masm->isolate()->factory()->undefined_value());
// Get function code.
__ mov(ebx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
__ mov(ebx, FieldOperand(ebx, SharedFunctionInfo::kCodeOffset));
__ lea(ebx, FieldOperand(ebx, Code::kHeaderSize));
// Re-run JSFunction, edi is function, esi is context.
__ jmp(ebx);
}
const bool LiveEdit::kFrameDropperSupported = true;
#undef __
} // namespace internal
} // namespace v8
#endif // V8_TARGET_ARCH_X87
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