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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.
#include "src/v8.h"
#if V8_TARGET_ARCH_MIPS
#include "src/codegen.h"
#include "src/debug.h"
namespace v8 {
namespace internal {
void BreakLocation::SetDebugBreakAtReturn() {
// Mips return sequence:
// mov sp, fp
// lw fp, sp(0)
// lw ra, sp(4)
// addiu sp, sp, 8
// addiu sp, sp, N
// jr ra
// nop (in branch delay slot)
// Make sure this constant matches the number if instrucntions we emit.
DCHECK(Assembler::kJSReturnSequenceInstructions == 7);
CodePatcher patcher(pc(), Assembler::kJSReturnSequenceInstructions);
// li and Call pseudo-instructions emit two instructions each.
patcher.masm()->li(v8::internal::t9, Operand(reinterpret_cast<int32_t>(
debug_info_->GetIsolate()->builtins()->Return_DebugBreak()->entry())));
patcher.masm()->Call(v8::internal::t9);
patcher.masm()->nop();
patcher.masm()->nop();
patcher.masm()->nop();
// TODO(mips): Open issue about using breakpoint instruction instead of nops.
// patcher.masm()->bkpt(0);
}
void BreakLocation::SetDebugBreakAtSlot() {
DCHECK(IsDebugBreakSlot());
// Patch the code changing the debug break slot code from:
// nop(DEBUG_BREAK_NOP) - nop(1) is sll(zero_reg, zero_reg, 1)
// nop(DEBUG_BREAK_NOP)
// nop(DEBUG_BREAK_NOP)
// nop(DEBUG_BREAK_NOP)
// to a call to the debug break slot code.
// li t9, address (lui t9 / ori t9 instruction pair)
// call t9 (jalr t9 / nop instruction pair)
CodePatcher patcher(pc(), Assembler::kDebugBreakSlotInstructions);
patcher.masm()->li(v8::internal::t9, Operand(reinterpret_cast<int32_t>(
debug_info_->GetIsolate()->builtins()->Slot_DebugBreak()->entry())));
patcher.masm()->Call(v8::internal::t9);
}
#define __ ACCESS_MASM(masm)
static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
RegList object_regs,
RegList non_object_regs) {
{
FrameScope scope(masm, StackFrame::INTERNAL);
// Load padding words on stack.
__ li(at, Operand(Smi::FromInt(LiveEdit::kFramePaddingValue)));
__ Subu(sp, sp,
Operand(kPointerSize * LiveEdit::kFramePaddingInitialSize));
for (int i = LiveEdit::kFramePaddingInitialSize - 1; i >= 0; i--) {
__ sw(at, MemOperand(sp, kPointerSize * i));
}
__ li(at, Operand(Smi::FromInt(LiveEdit::kFramePaddingInitialSize)));
__ push(at);
// 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) {
__ And(at, reg, 0xc0000000);
__ Assert(eq, kUnableToEncodeValueAsSmi, at, Operand(zero_reg));
}
__ sll(reg, reg, kSmiTagSize);
}
}
__ MultiPush(object_regs | non_object_regs);
}
#ifdef DEBUG
__ RecordComment("// Calling from debug break to runtime - come in - over");
#endif
__ PrepareCEntryArgs(0); // No arguments.
__ PrepareCEntryFunction(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) {
__ MultiPop(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) {
__ srl(reg, reg, kSmiTagSize);
}
if (FLAG_debug_code &&
(((object_regs |non_object_regs) & (1 << r)) == 0)) {
__ li(reg, 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());
__ li(t9, Operand(after_break_target));
__ lw(t9, MemOperand(t9));
__ Jump(t9);
}
void DebugCodegen::GenerateCallICStubDebugBreak(MacroAssembler* masm) {
// Register state for CallICStub
// ----------- S t a t e -------------
// -- a1 : function
// -- a3 : slot in feedback array (smi)
// -----------------------------------
Generate_DebugBreakCallHelper(masm, a1.bit() | a3.bit(), 0);
}
void DebugCodegen::GenerateLoadICDebugBreak(MacroAssembler* masm) {
Register receiver = LoadDescriptor::ReceiverRegister();
Register name = LoadDescriptor::NameRegister();
RegList regs = receiver.bit() | name.bit();
if (FLAG_vector_ics) {
regs |= VectorLoadICTrampolineDescriptor::SlotRegister().bit();
}
Generate_DebugBreakCallHelper(masm, regs, 0);
}
void DebugCodegen::GenerateStoreICDebugBreak(MacroAssembler* masm) {
// Calling convention for IC store (from ic-mips.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-mips.cc).
GenerateLoadICDebugBreak(masm);
}
void DebugCodegen::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
// Calling convention for IC keyed store call (from ic-mips.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 -------------
// -- a0 : value
// -----------------------------------
Generate_DebugBreakCallHelper(masm, a0.bit(), 0);
}
void DebugCodegen::GenerateReturnDebugBreak(MacroAssembler* masm) {
// In places other than IC call sites it is expected that v0 is TOS which
// is an object - this is not generally the case so this should be used with
// care.
Generate_DebugBreakCallHelper(masm, v0.bit(), 0);
}
void DebugCodegen::GenerateCallFunctionStubDebugBreak(MacroAssembler* masm) {
// Register state for CallFunctionStub (from code-stubs-mips.cc).
// ----------- S t a t e -------------
// -- a1 : function
// -----------------------------------
Generate_DebugBreakCallHelper(masm, a1.bit(), 0);
}
void DebugCodegen::GenerateCallConstructStubDebugBreak(MacroAssembler* masm) {
// Calling convention for CallConstructStub (from code-stubs-mips.cc).
// ----------- S t a t e -------------
// -- a0 : number of arguments (not smi)
// -- a1 : constructor function
// -----------------------------------
Generate_DebugBreakCallHelper(masm, a1.bit() , a0.bit());
}
void DebugCodegen::GenerateCallConstructStubRecordDebugBreak(
MacroAssembler* masm) {
// Calling convention for CallConstructStub (from code-stubs-mips.cc).
// ----------- S t a t e -------------
// -- a0 : number of arguments (not smi)
// -- a1 : constructor function
// -- a2 : feedback array
// -- a3 : feedback slot (smi)
// -----------------------------------
Generate_DebugBreakCallHelper(masm, a1.bit() | a2.bit() | a3.bit(), a0.bit());
}
void DebugCodegen::GenerateSlot(MacroAssembler* masm) {
// Generate enough nop's to make space for a call instruction. Avoid emitting
// the trampoline pool in the debug break slot code.
Assembler::BlockTrampolinePoolScope block_trampoline_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());
__ li(at, Operand(restarter_frame_function_slot));
__ sw(zero_reg, MemOperand(at, 0));
// We do not know our frame height, but set sp based on fp.
__ Subu(sp, fp, Operand(kPointerSize));
__ Pop(ra, fp, a1); // Return address, Frame, Function.
// Load context from the function.
__ lw(cp, FieldMemOperand(a1, JSFunction::kContextOffset));
// Get function code.
__ lw(at, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
__ lw(at, FieldMemOperand(at, SharedFunctionInfo::kCodeOffset));
__ Addu(t9, at, Operand(Code::kHeaderSize - kHeapObjectTag));
// Re-run JSFunction, a1 is function, cp is context.
__ Jump(t9);
}
const bool LiveEdit::kFrameDropperSupported = true;
#undef __
} } // namespace v8::internal
#endif // V8_TARGET_ARCH_MIPS