deps/v8/src/ia32/debug-ia32.cc
// 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.
#include "src/v8.h"
#if V8_TARGET_ARCH_IA32
#include "src/codegen.h"
#include "src/debug.h"
namespace v8 {
namespace internal {
bool BreakLocationIterator::IsDebugBreakAtReturn() {
return Debug::IsDebugBreakAtReturn(rinfo());
}
// Patch the JS frame exit code with a debug break call. See
// CodeGenerator::VisitReturnStatement and VirtualFrame::Exit in codegen-ia32.cc
// for the precise return instructions sequence.
void BreakLocationIterator::SetDebugBreakAtReturn() {
DCHECK(Assembler::kJSReturnSequenceLength >=
Assembler::kCallInstructionLength);
rinfo()->PatchCodeWithCall(
debug_info_->GetIsolate()->builtins()->Return_DebugBreak()->entry(),
Assembler::kJSReturnSequenceLength - Assembler::kCallInstructionLength);
}
// Restore the JS frame exit code.
void BreakLocationIterator::ClearDebugBreakAtReturn() {
rinfo()->PatchCode(original_rinfo()->pc(),
Assembler::kJSReturnSequenceLength);
}
// A debug break in the frame exit code is identified by the JS frame exit code
// having been patched with a call instruction.
bool Debug::IsDebugBreakAtReturn(RelocInfo* rinfo) {
DCHECK(RelocInfo::IsJSReturn(rinfo->rmode()));
return rinfo->IsPatchedReturnSequence();
}
bool BreakLocationIterator::IsDebugBreakAtSlot() {
DCHECK(IsDebugBreakSlot());
// Check whether the debug break slot instructions have been patched.
return rinfo()->IsPatchedDebugBreakSlotSequence();
}
void BreakLocationIterator::SetDebugBreakAtSlot() {
DCHECK(IsDebugBreakSlot());
Isolate* isolate = debug_info_->GetIsolate();
rinfo()->PatchCodeWithCall(
isolate->builtins()->Slot_DebugBreak()->entry(),
Assembler::kDebugBreakSlotLength - Assembler::kCallInstructionLength);
}
void BreakLocationIterator::ClearDebugBreakAtSlot() {
DCHECK(IsDebugBreakSlot());
rinfo()->PatchCode(original_rinfo()->pc(), Assembler::kDebugBreakSlotLength);
}
#define __ ACCESS_MASM(masm)
static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
RegList object_regs,
RegList non_object_regs,
bool convert_call_to_jmp) {
// 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)));
// Store the registers containing live values on the expression stack to
// make sure that these are correctly updated during GC. Non object values
// are stored as a smi causing it to be untouched by GC.
DCHECK((object_regs & ~kJSCallerSaved) == 0);
DCHECK((non_object_regs & ~kJSCallerSaved) == 0);
DCHECK((object_regs & non_object_regs) == 0);
for (int i = 0; i < kNumJSCallerSaved; i++) {
int r = JSCallerSavedCode(i);
Register reg = { r };
if ((object_regs & (1 << r)) != 0) {
__ push(reg);
}
if ((non_object_regs & (1 << r)) != 0) {
if (FLAG_debug_code) {
__ test(reg, Immediate(0xc0000000));
__ Assert(zero, kUnableToEncodeValueAsSmi);
}
__ SmiTag(reg);
__ push(reg);
}
}
#ifdef DEBUG
__ RecordComment("// Calling from debug break to runtime - come in - over");
#endif
__ Move(eax, Immediate(0)); // No arguments.
__ mov(ebx, Immediate(ExternalReference::debug_break(masm->isolate())));
CEntryStub ceb(masm->isolate(), 1);
__ CallStub(&ceb);
// Automatically find register that could be used after register restore.
// We need one register for padding skip instructions.
Register unused_reg = { -1 };
// Restore the register values containing object pointers from the
// expression stack.
for (int i = kNumJSCallerSaved; --i >= 0;) {
int r = JSCallerSavedCode(i);
Register reg = { r };
if (FLAG_debug_code) {
__ Move(reg, Immediate(kDebugZapValue));
}
bool taken = reg.code() == esi.code();
if ((object_regs & (1 << r)) != 0) {
__ pop(reg);
taken = true;
}
if ((non_object_regs & (1 << r)) != 0) {
__ pop(reg);
__ SmiUntag(reg);
taken = true;
}
if (!taken) {
unused_reg = reg;
}
}
DCHECK(unused_reg.code() != -1);
// Read current padding counter and skip corresponding number of words.
__ pop(unused_reg);
// We divide stored value by 2 (untagging) and multiply it by word's size.
STATIC_ASSERT(kSmiTagSize == 1 && kSmiShiftSize == 0);
__ lea(esp, Operand(esp, unused_reg, times_half_pointer_size, 0));
// Get rid of the internal frame.
}
// If this call did not replace a call but patched other code then there will
// be an unwanted return address left on the stack. Here we get rid of that.
if (convert_call_to_jmp) {
__ 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::GenerateCallICStubDebugBreak(MacroAssembler* masm) {
// Register state for CallICStub
// ----------- S t a t e -------------
// -- edx : type feedback slot (smi)
// -- edi : function
// -----------------------------------
Generate_DebugBreakCallHelper(masm, edx.bit() | edi.bit(),
0, false);
}
void DebugCodegen::GenerateLoadICDebugBreak(MacroAssembler* masm) {
// Register state for IC load call (from ic-ia32.cc).
Register receiver = LoadIC::ReceiverRegister();
Register name = LoadIC::NameRegister();
Generate_DebugBreakCallHelper(masm, receiver.bit() | name.bit(), 0, false);
}
void DebugCodegen::GenerateStoreICDebugBreak(MacroAssembler* masm) {
// Register state for IC store call (from ic-ia32.cc).
Register receiver = StoreIC::ReceiverRegister();
Register name = StoreIC::NameRegister();
Register value = StoreIC::ValueRegister();
Generate_DebugBreakCallHelper(
masm, receiver.bit() | name.bit() | value.bit(), 0, false);
}
void DebugCodegen::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
// Register state for keyed IC load call (from ic-ia32.cc).
GenerateLoadICDebugBreak(masm);
}
void DebugCodegen::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
// Register state for keyed IC store call (from ic-ia32.cc).
Register receiver = KeyedStoreIC::ReceiverRegister();
Register name = KeyedStoreIC::NameRegister();
Register value = KeyedStoreIC::ValueRegister();
Generate_DebugBreakCallHelper(
masm, receiver.bit() | name.bit() | value.bit(), 0, false);
}
void DebugCodegen::GenerateCompareNilICDebugBreak(MacroAssembler* masm) {
// Register state for CompareNil IC
// ----------- S t a t e -------------
// -- eax : value
// -----------------------------------
Generate_DebugBreakCallHelper(masm, eax.bit(), 0, false);
}
void DebugCodegen::GenerateReturnDebugBreak(MacroAssembler* masm) {
// Register state just before return from JS function (from codegen-ia32.cc).
// ----------- S t a t e -------------
// -- eax: return value
// -----------------------------------
Generate_DebugBreakCallHelper(masm, eax.bit(), 0, true);
}
void DebugCodegen::GenerateCallFunctionStubDebugBreak(MacroAssembler* masm) {
// Register state for CallFunctionStub (from code-stubs-ia32.cc).
// ----------- S t a t e -------------
// -- edi: function
// -----------------------------------
Generate_DebugBreakCallHelper(masm, edi.bit(), 0, false);
}
void DebugCodegen::GenerateCallConstructStubDebugBreak(MacroAssembler* masm) {
// Register state for CallConstructStub (from code-stubs-ia32.cc).
// eax is the actual number of arguments not encoded as a smi see comment
// above IC call.
// ----------- S t a t e -------------
// -- eax: number of arguments (not smi)
// -- edi: constructor function
// -----------------------------------
// The number of arguments in eax is not smi encoded.
Generate_DebugBreakCallHelper(masm, edi.bit(), eax.bit(), false);
}
void DebugCodegen::GenerateCallConstructStubRecordDebugBreak(
MacroAssembler* masm) {
// Register state for CallConstructStub (from code-stubs-ia32.cc).
// eax is the actual number of arguments not encoded as a smi see comment
// above IC call.
// ----------- S t a t e -------------
// -- eax: number of arguments (not smi)
// -- ebx: feedback array
// -- edx: feedback slot (smi)
// -- edi: constructor function
// -----------------------------------
// The number of arguments in eax is not smi encoded.
Generate_DebugBreakCallHelper(masm, ebx.bit() | edx.bit() | edi.bit(),
eax.bit(), false);
}
void DebugCodegen::GenerateSlot(MacroAssembler* masm) {
// Generate enough nop's to make space for a call instruction.
Label check_codesize;
__ bind(&check_codesize);
__ RecordDebugBreakSlot();
__ Nop(Assembler::kDebugBreakSlotLength);
DCHECK_EQ(Assembler::kDebugBreakSlotLength,
masm->SizeOfCodeGeneratedSince(&check_codesize));
}
void DebugCodegen::GenerateSlotDebugBreak(MacroAssembler* masm) {
// In the places where a debug break slot is inserted no registers can contain
// object pointers.
Generate_DebugBreakCallHelper(masm, 0, 0, true);
}
void DebugCodegen::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
masm->ret(0);
}
void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
ExternalReference restarter_frame_function_slot =
ExternalReference::debug_restarter_frame_function_pointer_address(
masm->isolate());
__ mov(Operand::StaticVariable(restarter_frame_function_slot), Immediate(0));
// We do not know our frame height, but set esp based on ebp.
__ lea(esp, Operand(ebp, -1 * kPointerSize));
__ pop(edi); // Function.
__ pop(ebp);
// Load context from the function.
__ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
// Get function code.
__ mov(edx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
__ mov(edx, FieldOperand(edx, SharedFunctionInfo::kCodeOffset));
__ lea(edx, FieldOperand(edx, Code::kHeaderSize));
// Re-run JSFunction, edi is function, esi is context.
__ jmp(edx);
}
const bool LiveEdit::kFrameDropperSupported = true;
#undef __
} } // namespace v8::internal
#endif // V8_TARGET_ARCH_IA32