// 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_ARM
#include "src/codegen.h"
#include "src/debug.h"
namespace v8 {
namespace internal {
bool BreakLocationIterator::IsDebugBreakAtReturn() {
return Debug::IsDebugBreakAtReturn(rinfo());
}
void BreakLocationIterator::SetDebugBreakAtReturn() {
// Patch the code changing the return from JS function sequence from
// mov sp, fp
// ldmia sp!, {fp, lr}
// add sp, sp, #4
// bx lr
// to a call to the debug break return code.
// ldr ip, [pc, #0]
// blx ip
// <debug break return code entry point address>
// bkpt 0
CodePatcher patcher(rinfo()->pc(), Assembler::kJSReturnSequenceInstructions);
patcher.masm()->ldr(v8::internal::ip, MemOperand(v8::internal::pc, 0));
patcher.masm()->blx(v8::internal::ip);
patcher.Emit(
debug_info_->GetIsolate()->builtins()->Return_DebugBreak()->entry());
patcher.masm()->bkpt(0);
}
// Restore the JS frame exit code.
void BreakLocationIterator::ClearDebugBreakAtReturn() {
rinfo()->PatchCode(original_rinfo()->pc(),
Assembler::kJSReturnSequenceInstructions);
}
// 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());
// Patch the code changing the debug break slot code from
// mov r2, r2
// mov r2, r2
// mov r2, r2
// to a call to the debug break slot code.
// ldr ip, [pc, #0]
// blx ip
// <debug break slot code entry point address>
CodePatcher patcher(rinfo()->pc(), Assembler::kDebugBreakSlotInstructions);
patcher.masm()->ldr(v8::internal::ip, MemOperand(v8::internal::pc, 0));
patcher.masm()->blx(v8::internal::ip);
patcher.Emit(
debug_info_->GetIsolate()->builtins()->Slot_DebugBreak()->entry());
}
void BreakLocationIterator::ClearDebugBreakAtSlot() {
DCHECK(IsDebugBreakSlot());
rinfo()->PatchCode(original_rinfo()->pc(),
Assembler::kDebugBreakSlotInstructions);
}
#define __ ACCESS_MASM(masm)
static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
RegList object_regs,
RegList non_object_regs) {
{
FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
// Load padding words on stack.
__ mov(ip, Operand(Smi::FromInt(LiveEdit::kFramePaddingValue)));
for (int i = 0; i < LiveEdit::kFramePaddingInitialSize; i++) {
__ push(ip);
}
__ mov(ip, Operand(Smi::FromInt(LiveEdit::kFramePaddingInitialSize)));
__ push(ip);
// 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);
if ((object_regs | non_object_regs) != 0) {
for (int i = 0; i < kNumJSCallerSaved; i++) {
int r = JSCallerSavedCode(i);
Register reg = { r };
if ((non_object_regs & (1 << r)) != 0) {
if (FLAG_debug_code) {
__ tst(reg, Operand(0xc0000000));
__ Assert(eq, kUnableToEncodeValueAsSmi);
}
__ SmiTag(reg);
}
}
__ stm(db_w, sp, object_regs | non_object_regs);
}
#ifdef DEBUG
__ RecordComment("// Calling from debug break to runtime - come in - over");
#endif
__ mov(r0, Operand::Zero()); // no arguments
__ mov(r1, Operand(ExternalReference::debug_break(masm->isolate())));
CEntryStub ceb(masm->isolate(), 1);
__ CallStub(&ceb);
// Restore the register values from the expression stack.
if ((object_regs | non_object_regs) != 0) {
__ ldm(ia_w, sp, object_regs | non_object_regs);
for (int i = 0; i < kNumJSCallerSaved; i++) {
int r = JSCallerSavedCode(i);
Register reg = { r };
if ((non_object_regs & (1 << r)) != 0) {
__ SmiUntag(reg);
}
if (FLAG_debug_code &&
(((object_regs |non_object_regs) & (1 << r)) == 0)) {
__ mov(reg, Operand(kDebugZapValue));
}
}
}
// Don't bother removing padding bytes pushed on the stack
// as the frame is going to be restored right away.
// Leave the internal frame.
}
// 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());
__ mov(ip, Operand(after_break_target));
__ ldr(ip, MemOperand(ip));
__ Jump(ip);
}
void DebugCodegen::GenerateCallICStubDebugBreak(MacroAssembler* masm) {
// Register state for CallICStub
// ----------- S t a t e -------------
// -- r1 : function
// -- r3 : slot in feedback array (smi)
// -----------------------------------
Generate_DebugBreakCallHelper(masm, r1.bit() | r3.bit(), 0);
}
void DebugCodegen::GenerateLoadICDebugBreak(MacroAssembler* masm) {
// Calling convention for IC load (from ic-arm.cc).
Register receiver = LoadDescriptor::ReceiverRegister();
Register name = LoadDescriptor::NameRegister();
Generate_DebugBreakCallHelper(masm, receiver.bit() | name.bit(), 0);
}
void DebugCodegen::GenerateStoreICDebugBreak(MacroAssembler* masm) {
// Calling convention for IC store (from ic-arm.cc).
Register receiver = StoreDescriptor::ReceiverRegister();
Register name = StoreDescriptor::NameRegister();
Register value = StoreDescriptor::ValueRegister();
Generate_DebugBreakCallHelper(
masm, receiver.bit() | name.bit() | value.bit(), 0);
}
void DebugCodegen::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
// Calling convention for keyed IC load (from ic-arm.cc).
GenerateLoadICDebugBreak(masm);
}
void DebugCodegen::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
// Calling convention for IC keyed store call (from ic-arm.cc).
Register receiver = StoreDescriptor::ReceiverRegister();
Register name = StoreDescriptor::NameRegister();
Register value = StoreDescriptor::ValueRegister();
Generate_DebugBreakCallHelper(
masm, receiver.bit() | name.bit() | value.bit(), 0);
}
void DebugCodegen::GenerateCompareNilICDebugBreak(MacroAssembler* masm) {
// Register state for CompareNil IC
// ----------- S t a t e -------------
// -- r0 : value
// -----------------------------------
Generate_DebugBreakCallHelper(masm, r0.bit(), 0);
}
void DebugCodegen::GenerateReturnDebugBreak(MacroAssembler* masm) {
// In places other than IC call sites it is expected that r0 is TOS which
// is an object - this is not generally the case so this should be used with
// care.
Generate_DebugBreakCallHelper(masm, r0.bit(), 0);
}
void DebugCodegen::GenerateCallFunctionStubDebugBreak(MacroAssembler* masm) {
// Register state for CallFunctionStub (from code-stubs-arm.cc).
// ----------- S t a t e -------------
// -- r1 : function
// -----------------------------------
Generate_DebugBreakCallHelper(masm, r1.bit(), 0);
}
void DebugCodegen::GenerateCallConstructStubDebugBreak(MacroAssembler* masm) {
// Calling convention for CallConstructStub (from code-stubs-arm.cc)
// ----------- S t a t e -------------
// -- r0 : number of arguments (not smi)
// -- r1 : constructor function
// -----------------------------------
Generate_DebugBreakCallHelper(masm, r1.bit(), r0.bit());
}
void DebugCodegen::GenerateCallConstructStubRecordDebugBreak(
MacroAssembler* masm) {
// Calling convention for CallConstructStub (from code-stubs-arm.cc)
// ----------- S t a t e -------------
// -- r0 : number of arguments (not smi)
// -- r1 : constructor function
// -- r2 : feedback array
// -- r3 : feedback slot (smi)
// -----------------------------------
Generate_DebugBreakCallHelper(masm, r1.bit() | r2.bit() | r3.bit(), r0.bit());
}
void DebugCodegen::GenerateSlot(MacroAssembler* masm) {
// Generate enough nop's to make space for a call instruction. Avoid emitting
// the constant pool in the debug break slot code.
Assembler::BlockConstPoolScope block_const_pool(masm);
Label check_codesize;
__ bind(&check_codesize);
__ RecordDebugBreakSlot();
for (int i = 0; i < Assembler::kDebugBreakSlotInstructions; i++) {
__ nop(MacroAssembler::DEBUG_BREAK_NOP);
}
DCHECK_EQ(Assembler::kDebugBreakSlotInstructions,
masm->InstructionsGeneratedSince(&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);
}
void DebugCodegen::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
__ Ret();
}
void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
ExternalReference restarter_frame_function_slot =
ExternalReference::debug_restarter_frame_function_pointer_address(
masm->isolate());
__ mov(ip, Operand(restarter_frame_function_slot));
__ mov(r1, Operand::Zero());
__ str(r1, MemOperand(ip, 0));
// Load the function pointer off of our current stack frame.
__ ldr(r1, MemOperand(fp,
StandardFrameConstants::kConstantPoolOffset - kPointerSize));
// Pop return address, frame and constant pool pointer (if
// FLAG_enable_ool_constant_pool).
__ LeaveFrame(StackFrame::INTERNAL);
{ ConstantPoolUnavailableScope constant_pool_unavailable(masm);
// Load context from the function.
__ ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset));
// Get function code.
__ ldr(ip, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
__ ldr(ip, FieldMemOperand(ip, SharedFunctionInfo::kCodeOffset));
__ add(ip, ip, Operand(Code::kHeaderSize - kHeapObjectTag));
// Re-run JSFunction, r1 is function, cp is context.
__ Jump(ip);
}
}
const bool LiveEdit::kFrameDropperSupported = true;
#undef __
} } // namespace v8::internal
#endif // V8_TARGET_ARCH_ARM