Author: [email protected]
Date: Thu Jul 9 06:30:27 2009
New Revision: 2421
Modified:
branches/bleeding_edge/src/debug.h
branches/bleeding_edge/src/x64/assembler-x64.cc
branches/bleeding_edge/src/x64/codegen-x64.cc
branches/bleeding_edge/src/x64/debug-x64.cc
Log:
X64: Let debugger patch JSReturn with a debug break.
Review URL: http://codereview.chromium.org/155286
Modified: branches/bleeding_edge/src/debug.h
==============================================================================
--- branches/bleeding_edge/src/debug.h (original)
+++ branches/bleeding_edge/src/debug.h Thu Jul 9 06:30:27 2009
@@ -363,6 +363,10 @@
static const int kIa32CallInstructionLength = 5;
static const int kIa32JSReturnSequenceLength = 6;
+ // The x64 JS return sequence is padded with int3 to make it large
+ // enough to hold a call instruction when the debugger patches it.
+ static const int kX64JSReturnSequenceLength = 13;
+
// Code generator routines.
static void GenerateLoadICDebugBreak(MacroAssembler* masm);
static void GenerateStoreICDebugBreak(MacroAssembler* masm);
Modified: branches/bleeding_edge/src/x64/assembler-x64.cc
==============================================================================
--- branches/bleeding_edge/src/x64/assembler-x64.cc (original)
+++ branches/bleeding_edge/src/x64/assembler-x64.cc Thu Jul 9 06:30:27 2009
@@ -73,45 +73,8 @@
XMMRegister xmm15 = { 15 };
-Operand::Operand(Register base, int32_t disp): rex_(0) {
- len_ = 1;
- if (base.is(rsp) || base.is(r12)) {
- // SIB byte is needed to encode (rsp + offset) or (r12 + offset).
- set_sib(times_1, rsp, base);
- }
-
- if (disp == 0 && !base.is(rbp) && !base.is(r13)) {
- set_modrm(0, base);
- } else if (is_int8(disp)) {
- set_modrm(1, base);
- set_disp8(disp);
- } else {
- set_modrm(2, base);
- set_disp32(disp);
- }
-}
-
-
-Operand::Operand(Register base,
- Register index,
- ScaleFactor scale,
- int32_t disp): rex_(0) {
- ASSERT(!index.is(rsp));
- len_ = 1;
- set_sib(scale, index, base);
- if (disp == 0 && !base.is(rbp) && !base.is(r13)) {
- // This call to set_modrm doesn't overwrite the REX.B (or REX.X) bits
- // possibly set by set_sib.
- set_modrm(0, rsp);
- } else if (is_int8(disp)) {
- set_modrm(1, rsp);
- set_disp8(disp);
- } else {
- set_modrm(2, rsp);
- set_disp32(disp);
- }
-}
-
+//
-----------------------------------------------------------------------------
+// Implementation of CpuFeatures
// The required user mode extensions in X64 are (from AMD64 ABI Table A.1):
// fpu, tsc, cx8, cmov, mmx, sse, sse2, fxsr, syscall
@@ -192,6 +155,71 @@
ASSERT(IsSupported(SSE2));
ASSERT(IsSupported(CMOV));
}
+
+
+//
-----------------------------------------------------------------------------
+// Implementation of RelocInfo
+
+// Patch the code at the current PC with a call to the target address.
+// Additional guard int3 instructions can be added if required.
+void RelocInfo::PatchCodeWithCall(Address target, int guard_bytes) {
+ // Call instruction takes up 13 bytes and int3 takes up one byte.
+ Address patch_site = pc_;
+ Memory::uint16_at(patch_site) = 0xBA49u; // movq r10, imm64
+ // Write "0x00, call r10" starting at last byte of address. We overwrite
+ // the 0x00 later, and this lets us write a uint32.
+ Memory::uint32_at(patch_site + 9) = 0xD2FF4900u; // 0x00, call r10
+ Memory::Address_at(patch_site + 2) = target;
+
+ // Add the requested number of int3 instructions after the call.
+ for (int i = 0; i < guard_bytes; i++) {
+ *(patch_site + 13 + i) = 0xCC; // int3
+ }
+}
+
+
+//
-----------------------------------------------------------------------------
+// Implementation of Operand
+
+Operand::Operand(Register base, int32_t disp): rex_(0) {
+ len_ = 1;
+ if (base.is(rsp) || base.is(r12)) {
+ // SIB byte is needed to encode (rsp + offset) or (r12 + offset).
+ set_sib(times_1, rsp, base);
+ }
+
+ if (disp == 0 && !base.is(rbp) && !base.is(r13)) {
+ set_modrm(0, base);
+ } else if (is_int8(disp)) {
+ set_modrm(1, base);
+ set_disp8(disp);
+ } else {
+ set_modrm(2, base);
+ set_disp32(disp);
+ }
+}
+
+
+Operand::Operand(Register base,
+ Register index,
+ ScaleFactor scale,
+ int32_t disp): rex_(0) {
+ ASSERT(!index.is(rsp));
+ len_ = 1;
+ set_sib(scale, index, base);
+ if (disp == 0 && !base.is(rbp) && !base.is(r13)) {
+ // This call to set_modrm doesn't overwrite the REX.B (or REX.X) bits
+ // possibly set by set_sib.
+ set_modrm(0, rsp);
+ } else if (is_int8(disp)) {
+ set_modrm(1, rsp);
+ set_disp8(disp);
+ } else {
+ set_modrm(2, rsp);
+ set_disp32(disp);
+ }
+}
+
//
-----------------------------------------------------------------------------
// Implementation of Assembler
Modified: branches/bleeding_edge/src/x64/codegen-x64.cc
==============================================================================
--- branches/bleeding_edge/src/x64/codegen-x64.cc (original)
+++ branches/bleeding_edge/src/x64/codegen-x64.cc Thu Jul 9 06:30:27 2009
@@ -355,14 +355,19 @@
// receiver.
frame_->Exit();
masm_->ret((scope_->num_parameters() + 1) * kPointerSize);
+ // Add padding that will be overwritten by a debugger breakpoint.
+ // frame_->Exit() generates "movq rsp, rbp; pop rbp" length 5.
+ // "ret k" has length 2.
+ const int kPadding = Debug::kX64JSReturnSequenceLength - 5 - 2;
+ for (int i = 0; i < kPadding; ++i) {
+ masm_->int3();
+ }
DeleteFrame();
- // TODO(x64): introduce kX64JSReturnSequenceLength and enable assert.
-
// Check that the size of the code used for returning matches what is
// expected by the debugger.
- // ASSERT_EQ(Debug::kIa32JSReturnSequenceLength,
- // masm_->SizeOfCodeGeneratedSince(&check_exit_codesize));
+ ASSERT_EQ(Debug::kX64JSReturnSequenceLength,
+ masm_->SizeOfCodeGeneratedSince(&check_exit_codesize));
}
Modified: branches/bleeding_edge/src/x64/debug-x64.cc
==============================================================================
--- branches/bleeding_edge/src/x64/debug-x64.cc (original)
+++ branches/bleeding_edge/src/x64/debug-x64.cc Thu Jul 9 06:30:27 2009
@@ -38,8 +38,10 @@
#ifdef ENABLE_DEBUGGER_SUPPORT
bool Debug::IsDebugBreakAtReturn(v8::internal::RelocInfo* rinfo) {
- UNIMPLEMENTED();
- return false;
+ ASSERT(RelocInfo::IsJSReturn(rinfo->rmode()));
+ // 11th byte of patch is 0x49, 11th byte of JS return is 0xCC (int3).
+ ASSERT(*(rinfo->pc() + 10) == 0x49 || *(rinfo->pc() + 10) == 0xCC);
+ return (*(rinfo->pc() + 10) == 0x49);
}
void Debug::GenerateCallICDebugBreak(MacroAssembler* masm) {
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