// Copyright 2011 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "v8.h"
#if defined(V8_TARGET_ARCH_ARM)
#include "codegen.h"
#include "debug.h"
namespace v8 {
namespace internal {
#ifdef ENABLE_DEBUGGER_SUPPORT
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.
// #if USE_BLX
// ldr ip, [pc, #0]
// blx ip
// #else
// mov lr, pc
// ldr pc, [pc, #-4]
// #endif
// <debug break return code entry point address>
// bktp 0
CodePatcher patcher(rinfo()->pc(), Assembler::kJSReturnSequenceInstructions);
#ifdef USE_BLX
patcher.masm()->ldr(v8::internal::ip, MemOperand(v8::internal::pc, 0));
patcher.masm()->blx(v8::internal::ip);
#else
patcher.masm()->mov(v8::internal::lr, v8::internal::pc);
patcher.masm()->ldr(v8::internal::pc, MemOperand(v8::internal::pc, -4));
#endif
patcher.Emit(Isolate::Current()->debug()->debug_break_return()->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) {
ASSERT(RelocInfo::IsJSReturn(rinfo->rmode()));
return rinfo->IsPatchedReturnSequence();
}
bool BreakLocationIterator::IsDebugBreakAtSlot() {
ASSERT(IsDebugBreakSlot());
// Check whether the debug break slot instructions have been patched.
return rinfo()->IsPatchedDebugBreakSlotSequence();
}
void BreakLocationIterator::SetDebugBreakAtSlot() {
ASSERT(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.
// #if USE_BLX
// ldr ip, [pc, #0]
// blx ip
// #else
// mov lr, pc
// ldr pc, [pc, #-4]
// #endif
// <debug break slot code entry point address>
CodePatcher patcher(rinfo()->pc(), Assembler::kDebugBreakSlotInstructions);
#ifdef USE_BLX
patcher.masm()->ldr(v8::internal::ip, MemOperand(v8::internal::pc, 0));
patcher.masm()->blx(v8::internal::ip);
#else
patcher.masm()->mov(v8::internal::lr, v8::internal::pc);
patcher.masm()->ldr(v8::internal::pc, MemOperand(v8::internal::pc, -4));
#endif
patcher.Emit(Isolate::Current()->debug()->debug_break_slot()->entry());
}
void BreakLocationIterator::ClearDebugBreakAtSlot() {
ASSERT(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) {
{
FrameScope scope(masm, StackFrame::INTERNAL);
// 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.
ASSERT((object_regs & ~kJSCallerSaved) == 0);
ASSERT((non_object_regs & ~kJSCallerSaved) == 0);
ASSERT((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, "Unable to encode value as smi");
}
__ mov(reg, Operand(reg, LSL, kSmiTagSize));
}
}
__ 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(0, RelocInfo::NONE)); // no arguments
__ mov(r1, Operand(ExternalReference::debug_break(masm->isolate())));
CEntryStub ceb(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) {
__ mov(reg, Operand(reg, LSR, kSmiTagSize));
}
if (FLAG_debug_code &&
(((object_regs |non_object_regs) & (1 << r)) == 0)) {
__ mov(reg, Operand(kDebugZapValue));
}
}
}
// 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_Address::AfterBreakTarget(), masm->isolate());
__ mov(ip, Operand(after_break_target));
__ ldr(ip, MemOperand(ip));
__ Jump(ip);
}
void Debug::GenerateLoadICDebugBreak(MacroAssembler* masm) {
// Calling convention for IC load (from ic-arm.cc).
// ----------- S t a t e -------------
// -- r2 : name
// -- lr : return address
// -- r0 : receiver
// -- [sp] : receiver
// -----------------------------------
// Registers r0 and r2 contain objects that need to be pushed on the
// expression stack of the fake JS frame.
Generate_DebugBreakCallHelper(masm, r0.bit() | r2.bit(), 0);
}
void Debug::GenerateStoreICDebugBreak(MacroAssembler* masm) {
// Calling convention for IC store (from ic-arm.cc).
// ----------- S t a t e -------------
// -- r0 : value
// -- r1 : receiver
// -- r2 : name
// -- lr : return address
// -----------------------------------
// Registers r0, r1, and r2 contain objects that need to be pushed on the
// expression stack of the fake JS frame.
Generate_DebugBreakCallHelper(masm, r0.bit() | r1.bit() | r2.bit(), 0);
}
void Debug::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
// ---------- S t a t e --------------
// -- lr : return address
// -- r0 : key
// -- r1 : receiver
Generate_DebugBreakCallHelper(masm, r0.bit() | r1.bit(), 0);
}
void Debug::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
// ---------- S t a t e --------------
// -- r0 : value
// -- r1 : key
// -- r2 : receiver
// -- lr : return address
Generate_DebugBreakCallHelper(masm, r0.bit() | r1.bit() | r2.bit(), 0);
}
void Debug::GenerateCallICDebugBreak(MacroAssembler* masm) {
// Calling convention for IC call (from ic-arm.cc)
// ----------- S t a t e -------------
// -- r2 : name
// -----------------------------------
Generate_DebugBreakCallHelper(masm, r2.bit(), 0);
}
void Debug::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 Debug::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 Debug::GenerateCallFunctionStubRecordDebugBreak(MacroAssembler* masm) {
// Register state for CallFunctionStub (from code-stubs-arm.cc).
// ----------- S t a t e -------------
// -- r1 : function
// -- r2 : cache cell for call target
// -----------------------------------
Generate_DebugBreakCallHelper(masm, r1.bit() | r2.bit(), 0);
}
void Debug::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 Debug::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 : cache cell for call target
// -----------------------------------
Generate_DebugBreakCallHelper(masm, r1.bit() | r2.bit(), r0.bit());
}
void Debug::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);
}
ASSERT_EQ(Assembler::kDebugBreakSlotInstructions,
masm->InstructionsGeneratedSince(&check_codesize));
}
void Debug::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 Debug::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
masm->Abort("LiveEdit frame dropping is not supported on arm");
}
void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
masm->Abort("LiveEdit frame dropping is not supported on arm");
}
const bool Debug::kFrameDropperSupported = false;
#undef __
#endif // ENABLE_DEBUGGER_SUPPORT
} } // namespace v8::internal
#endif // V8_TARGET_ARCH_ARM