Reland Implement .eh_frame writer and disassembler.

Original commit message:

  Also, CodeGenerator::MakeCodeEpilogue now accepts an optional pointer
  to a EhFrameWriter and will attach unwinding information to the code
  object when passed one.

Reason for reverting:

  The STATIC_CONST_MEMBER_DEFINITION in eh-frame-writer-unittest.cc
  causes a compiler error on V8 Win64 - clang buildbot.

  Removing that bit.

BUG=v8:4899
LOG=N

Review-Url: https://codereview.chromium.org/2023503002
Cr-Commit-Position: refs/heads/master@{#37707}

BUILD.gn

@@ -1635,6 +1635,7 @@ v8_source_set("v8_base") {
       "src/x64/cpu-x64.cc",
       "src/x64/deoptimizer-x64.cc",
       "src/x64/disasm-x64.cc",
+      "src/x64/eh-frame-x64.cc",
       "src/x64/frames-x64.cc",
       "src/x64/frames-x64.h",
       "src/x64/interface-descriptors-x64.cc",
@@ -1656,6 +1657,7 @@ v8_source_set("v8_base") {
       "src/arm/cpu-arm.cc",
       "src/arm/deoptimizer-arm.cc",
       "src/arm/disasm-arm.cc",
+      "src/arm/eh-frame-arm.cc",
       "src/arm/frames-arm.cc",
       "src/arm/frames-arm.h",
       "src/arm/interface-descriptors-arm.cc",
@@ -1702,6 +1704,7 @@ v8_source_set("v8_base") {
       "src/arm64/deoptimizer-arm64.cc",
       "src/arm64/disasm-arm64.cc",
       "src/arm64/disasm-arm64.h",
+      "src/arm64/eh-frame-arm64.cc",
       "src/arm64/frames-arm64.cc",
       "src/arm64/frames-arm64.h",
       "src/arm64/instructions-arm64.cc",

src/arm/eh-frame-arm.cc

+// Copyright 2016 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/eh-frame.h"
+
+namespace v8 {
+namespace internal {
+
+static const int kR0DwarfCode = 0;
+static const int kFpDwarfCode = 11;
+static const int kSpDwarfCode = 13;
+static const int kLrDwarfCode = 14;
+
+STATIC_CONST_MEMBER_DEFINITION const int
+    EhFrameConstants::kCodeAlignmentFactor = 4;
+
+STATIC_CONST_MEMBER_DEFINITION const int
+    EhFrameConstants::kDataAlignmentFactor = -4;
+
+void EhFrameWriter::WriteReturnAddressRegisterCode() {
+  WriteULeb128(kLrDwarfCode);
+}
+
+void EhFrameWriter::WriteInitialStateInCie() {
+  SetBaseAddressRegisterAndOffset(fp, 0);
+  RecordRegisterNotModified(lr);
+}
+
+// static
+int EhFrameWriter::RegisterToDwarfCode(Register name) {
+  switch (name.code()) {
+    case Register::kCode_fp:
+      return kFpDwarfCode;
+    case Register::kCode_sp:
+      return kSpDwarfCode;
+    case Register::kCode_lr:
+      return kLrDwarfCode;
+    case Register::kCode_r0:
+      return kR0DwarfCode;
+    default:
+      UNIMPLEMENTED();
+      return -1;
+  }
+}
+
+#ifdef ENABLE_DISASSEMBLER
+
+// static
+const char* EhFrameDisassembler::DwarfRegisterCodeToString(int code) {
+  switch (code) {
+    case kFpDwarfCode:
+      return "fp";
+    case kSpDwarfCode:
+      return "sp";
+    case kLrDwarfCode:
+      return "lr";
+    default:
+      UNIMPLEMENTED();
+      return nullptr;
+  }
+}
+
+#endif
+
+}  // namespace internal
+}  // namespace v8

src/arm64/eh-frame-arm64.cc

+// Copyright 2016 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/eh-frame.h"
+
+namespace v8 {
+namespace internal {
+
+static const int kX0DwarfCode = 0;
+static const int kJsSpDwarfCode = 28;
+static const int kFpDwarfCode = 29;
+static const int kLrDwarfCode = 30;
+static const int kCSpDwarfCode = 31;
+
+STATIC_CONST_MEMBER_DEFINITION const int
+    EhFrameConstants::kCodeAlignmentFactor = 4;
+
+STATIC_CONST_MEMBER_DEFINITION const int
+    EhFrameConstants::kDataAlignmentFactor = -8;
+
+void EhFrameWriter::WriteReturnAddressRegisterCode() {
+  WriteULeb128(kLrDwarfCode);
+}
+
+void EhFrameWriter::WriteInitialStateInCie() {
+  SetBaseAddressRegisterAndOffset(x29, 0);
+  RecordRegisterNotModified(x30);
+}
+
+// static
+int EhFrameWriter::RegisterToDwarfCode(Register name) {
+  switch (name.code()) {
+    case Register::kCode_x28:
+      return kJsSpDwarfCode;
+    case Register::kCode_x29:
+      return kFpDwarfCode;
+    case Register::kCode_x30:
+      return kLrDwarfCode;
+    case Register::kCode_x31:
+      return kCSpDwarfCode;
+    case Register::kCode_x0:
+      return kX0DwarfCode;
+    default:
+      UNIMPLEMENTED();
+      return -1;
+  }
+}
+
+#ifdef ENABLE_DISASSEMBLER
+
+// static
+const char* EhFrameDisassembler::DwarfRegisterCodeToString(int code) {
+  switch (code) {
+    case kFpDwarfCode:
+      return "fp";
+    case kLrDwarfCode:
+      return "lr";
+    case kJsSpDwarfCode:
+      return "jssp";
+    case kCSpDwarfCode:
+      return "csp";  // This could be zr as well
+    default:
+      UNIMPLEMENTED();
+      return nullptr;
+  }
+}
+
+#endif
+
+}  // namespace internal
+}  // namespace v8

src/codegen.cc

@@ -11,6 +11,7 @@
 #include "src/bootstrapper.h"
 #include "src/compiler.h"
 #include "src/debug/debug.h"
+#include "src/eh-frame.h"
 #include "src/parsing/parser.h"
 #include "src/runtime/runtime.h"
 
@@ -117,8 +118,8 @@ void CodeGenerator::MakeCodePrologue(CompilationInfo* info, const char* kind) {
 #endif  // DEBUG
 }
 
-
 Handle<Code> CodeGenerator::MakeCodeEpilogue(MacroAssembler* masm,
+                                             EhFrameWriter* eh_frame_writer,
                                              CompilationInfo* info) {
   Isolate* isolate = info->isolate();
 
@@ -129,6 +130,7 @@ Handle<Code> CodeGenerator::MakeCodeEpilogue(MacroAssembler* masm,
       Code::ExtractKindFromFlags(flags) == Code::OPTIMIZED_FUNCTION ||
       info->IsStub();
   masm->GetCode(&desc);
+  if (eh_frame_writer) eh_frame_writer->GetEhFrame(&desc);
   Handle<Code> code =
       isolate->factory()->NewCode(desc, flags, masm->CodeObject(),
                                   false, is_crankshafted,

src/codegen.h

@@ -69,7 +69,7 @@ namespace internal {
 
 
 class CompilationInfo;
-
+class EhFrameWriter;
 
 class CodeGenerator {
  public:
@@ -78,6 +78,7 @@ class CodeGenerator {
 
   // Allocate and install the code.
   static Handle<Code> MakeCodeEpilogue(MacroAssembler* masm,
+                                       EhFrameWriter* unwinding,
                                        CompilationInfo* info);
 
   // Print the code after compiling it.

src/compiler/code-generator.cc

@@ -204,7 +204,7 @@ Handle<Code> CodeGenerator::GenerateCode() {
   safepoints()->Emit(masm(), frame()->GetTotalFrameSlotCount());
 
   Handle<Code> result =
-      v8::internal::CodeGenerator::MakeCodeEpilogue(masm(), info);
+      v8::internal::CodeGenerator::MakeCodeEpilogue(masm(), nullptr, info);
   result->set_is_turbofanned(true);
   result->set_stack_slots(frame()->GetTotalFrameSlotCount());
   result->set_safepoint_table_offset(safepoints()->GetCodeOffset());

src/crankshaft/lithium.cc

@@ -457,7 +457,8 @@ Handle<Code> LChunk::Codegen() {
   if (generator.GenerateCode()) {
     generator.CheckEnvironmentUsage();
     CodeGenerator::MakeCodePrologue(info(), "optimized");
-    Handle<Code> code = CodeGenerator::MakeCodeEpilogue(&assembler, info());
+    Handle<Code> code =
+        CodeGenerator::MakeCodeEpilogue(&assembler, nullptr, info());
     generator.FinishCode(code);
     CommitDependencies(code);
     generator.source_position_table_builder()->EndJitLogging(

src/eh-frame.h

@@ -5,36 +5,292 @@
 #ifndef V8_EH_FRAME_H_
 #define V8_EH_FRAME_H_
 
-#include <cstdint>
+#include "src/macro-assembler.h"
 
 namespace v8 {
 namespace internal {
 
-class Code;
+class EhFrameConstants final {
+ public:
+  enum class DwarfOpcodes : byte {
+    kNop = 0x00,
+    kAdvanceLoc1 = 0x02,
+    kAdvanceLoc2 = 0x03,
+    kAdvanceLoc4 = 0x04,
+    kSameValue = 0x08,
+    kDefCfa = 0x0c,
+    kDefCfaRegister = 0x0d,
+    kDefCfaOffset = 0x0e,
+    kOffsetExtendedSf = 0x11,
+  };
+
+  enum DwarfEncodingSpecifiers : byte {
+    kUData4 = 0x03,
+    kSData4 = 0x0b,
+    kPcRel = 0x10,
+    kDataRel = 0x30,
+    kOmit = 0xff,
+  };
+
+  static const int kLocationTag = 1;
+  static const int kLocationMask = 0x3f;
+  static const int kLocationMaskSize = 6;
+
+  static const int kSavedRegisterTag = 2;
+  static const int kSavedRegisterMask = 0x3f;
+  static const int kSavedRegisterMaskSize = 6;
+
+  static const int kFollowInitialRuleTag = 3;
+  static const int kFollowInitialRuleMask = 0x3f;
+  static const int kFollowInitialRuleMaskSize = 6;
+
+  static const int kProcedureAddressOffsetInFde = 2 * kInt32Size;
+  static const int kProcedureSizeOffsetInFde = 3 * kInt32Size;
+
+  static const int kInitialStateOffsetInCie = 19;
+  static const int kEhFrameTerminatorSize = 4;
+
+  // Defined in eh-writer-<arch>.cc
+  static const int kCodeAlignmentFactor;
+  static const int kDataAlignmentFactor;
+
+  static const int kFdeVersionSize = 1;
+  static const int kFdeEncodingSpecifiersSize = 3;
+
+  static const int kEhFrameHdrVersion = 1;
+  static const int kEhFrameHdrSize = 20;
+};
+
+class EhFrameWriter {
+ public:
+  explicit EhFrameWriter(Zone* zone);
+
+  // The empty frame is a hack to trigger fp-based unwinding in Linux perf
+  // compiled with libunwind support when processing DWARF-based call graphs.
+  //
+  // It is effectively a valid eh_frame_hdr with an empty look up table.
+  //
+  static void WriteEmptyEhFrame(std::ostream& stream);  // NOLINT
+
+  // Write the CIE and FDE header. Call it before any other method.
+  void Initialize();
+
+  void AdvanceLocation(int pc_offset);
+
+  // The <base_address> is the one to which all <offset>s in SaveRegisterToStack
+  // directives are relative. It is given by <base_register> + <base_offset>.
+  //
+  // The <base_offset> must be positive or 0.
+  //
+  void SetBaseAddressRegister(Register base_register);
+  void SetBaseAddressOffset(int base_offset);
+  void IncreaseBaseAddressOffset(int base_delta) {
+    SetBaseAddressOffset(base_offset_ + base_delta);
+  }
+  void SetBaseAddressRegisterAndOffset(Register base_register, int base_offset);
+
+  // Register saved at location <base_address> + <offset>.
+  // The <offset> must be a multiple of EhFrameConstants::kDataAlignment.
+  void RecordRegisterSavedToStack(Register name, int offset) {
+    RecordRegisterSavedToStack(RegisterToDwarfCode(name), offset);
+  }
+
+  // The register has not been modified from the previous frame.
+  void RecordRegisterNotModified(Register name);
+
+  // The register follows the rule defined in the CIE.
+  void RecordRegisterFollowsInitialRule(Register name);
+
+  void Finish(int code_size);
+
+  // Remember to call Finish() before GetEhFrame().
+  //
+  // The EhFrameWriter instance owns the buffer pointed by
+  // CodeDesc::unwinding_info, and must outlive any use of the CodeDesc.
+  //
+  void GetEhFrame(CodeDesc* desc);
+
+  int last_pc_offset() const { return last_pc_offset_; }
+  Register base_register() const { return base_register_; }
+  int base_offset() const { return base_offset_; }
+
+ private:
+  enum class InternalState { kUndefined, kInitialized, kFinalized };
+
+  static const uint32_t kInt32Placeholder = 0xdeadc0de;
+
+  void WriteSLeb128(int32_t value);
+  void WriteULeb128(uint32_t value);
+
+  void WriteByte(byte value) { eh_frame_buffer_.push_back(value); }
+  void WriteOpcode(EhFrameConstants::DwarfOpcodes opcode) {
+    WriteByte(static_cast<byte>(opcode));
+  }
+  void WriteBytes(const byte* start, int size) {
+    eh_frame_buffer_.insert(eh_frame_buffer_.end(), start, start + size);
+  }
+  void WriteInt16(uint16_t value) {
+    WriteBytes(reinterpret_cast<const byte*>(&value), sizeof(value));
+  }
+  void WriteInt32(uint32_t value) {
+    WriteBytes(reinterpret_cast<const byte*>(&value), sizeof(value));
+  }
+  void PatchInt32(int base_offset, uint32_t value) {
+    DCHECK_EQ(ReadUnalignedUInt32(eh_frame_buffer_.data() + base_offset),
+              kInt32Placeholder);
+    DCHECK_LT(base_offset + kInt32Size, eh_frame_offset());
+    WriteUnalignedUInt32(eh_frame_buffer_.data() + base_offset, value);
+  }
+
+  // Write the common information entry, which includes encoding specifiers,
+  // alignment factors, the return address (pseudo) register code and the
+  // directives to construct the initial state of the unwinding table.
+  void WriteCie();
+
+  // Write the header of the function data entry, containing a pointer to the
+  // correspondent CIE and the position and size of the associated routine.
+  void WriteFdeHeader();
+
+  // Write the contents of the .eh_frame_hdr section, including encoding
+  // specifiers and the routine => FDE lookup table.
+  void WriteEhFrameHdr(int code_size);
+
+  // Write nops to the buffer until the size reaches a multiple of 8 bytes.
+  void WritePaddingTo8ByteAlignment();
+
+  // Internal version that directly accepts a DWARF register code, needed for
+  // handling pseudo-registers on some platforms.
+  void RecordRegisterSavedToStack(int register_code, int offset);
 
-class EhFrameHdr final {
+  int GetProcedureAddressOffset() const {
+    return fde_offset() + EhFrameConstants::kProcedureAddressOffsetInFde;
+  }
+
+  int GetProcedureSizeOffset() const {
+    return fde_offset() + EhFrameConstants::kProcedureSizeOffsetInFde;
+  }
+
+  int eh_frame_offset() const {
+    return static_cast<int>(eh_frame_buffer_.size());
+  }
+
+  int fde_offset() const { return cie_size_; }
+
+  // Platform specific functions implemented in eh-frame-<arch>.cc
+
+  static int RegisterToDwarfCode(Register name);
+
+  // Write directives to build the initial state in the CIE.
+  void WriteInitialStateInCie();
+
+  // Write the return address (pseudo) register code.
+  void WriteReturnAddressRegisterCode();
+
+  int cie_size_;
+  int last_pc_offset_;
+  InternalState writer_state_;
+  Register base_register_;
+  int base_offset_;
+  ZoneVector<byte> eh_frame_buffer_;
+
+  DISALLOW_COPY_AND_ASSIGN(EhFrameWriter);
+};
+
+class EhFrameIterator {
  public:
-  static const int kRecordSize = 20;
-  static const int kCIESize;
+  EhFrameIterator(const byte* start, const byte* end)
+      : start_(start), next_(start), end_(end) {
+    DCHECK_LE(start, end);
+  }
+
+  void SkipCie() {
+    DCHECK_EQ(next_, start_);
+    next_ += ReadUnalignedUInt32(next_) + kInt32Size;
+  }
+
+  void SkipToFdeDirectives() {
+    SkipCie();
+    // Skip the FDE header.
+    Skip(kDirectivesOffsetInFde);
+  }
+
+  void Skip(int how_many) {
+    DCHECK_GE(how_many, 0);
+    next_ += how_many;
+    DCHECK_LE(next_, end_);
+  }
+
+  uint32_t GetNextUInt32() { return GetNextValue<uint32_t>(); }
+  uint16_t GetNextUInt16() { return GetNextValue<uint16_t>(); }
+  byte GetNextByte() { return GetNextValue<byte>(); }
+  EhFrameConstants::DwarfOpcodes GetNextOpcode() {
+    return static_cast<EhFrameConstants::DwarfOpcodes>(GetNextByte());
+  }
+
+  uint32_t GetNextULeb128();
+  int32_t GetNextSLeb128();
+
+  bool Done() const {
+    DCHECK_LE(next_, end_);
+    return next_ == end_;
+  }
 
-  explicit EhFrameHdr(Code* code);
+  int GetCurrentOffset() const {
+    DCHECK_GE(next_, start_);
+    return static_cast<int>(next_ - start_);
+  }
 
-  int32_t offset_to_eh_frame() const { return offset_to_eh_frame_; }
-  uint32_t lut_entries_number() const { return lut_entries_number_; }
-  int32_t offset_to_procedure() const { return offset_to_procedure_; }
-  int32_t offset_to_fde() const { return offset_to_fde_; }
+  int GetBufferSize() { return static_cast<int>(end_ - start_); }
+
+  const void* current_address() const {
+    return reinterpret_cast<const void*>(next_);
+  }
+
+ private:
+  static const int kDirectivesOffsetInFde = 4 * kInt32Size + 1;
+
+  static uint32_t DecodeULeb128(const byte* encoded, int* encoded_size);
+  static int32_t DecodeSLeb128(const byte* encoded, int* encoded_size);
+
+  template <typename T>
+  T GetNextValue() {
+    T result;
+    DCHECK_LE(next_ + sizeof(result), end_);
+    result = ReadUnalignedValue<T>(next_);
+    next_ += sizeof(result);
+    return result;
+  }
+
+  const byte* start_;
+  const byte* next_;
+  const byte* end_;
+};
+
+#ifdef ENABLE_DISASSEMBLER
+
+class EhFrameDisassembler final {
+ public:
+  EhFrameDisassembler(const byte* start, const byte* end)
+      : start_(start), end_(end) {
+    DCHECK_LT(start, end);
+  }
+
+  void DisassembleToStream(std::ostream& stream);  // NOLINT
 
  private:
-  uint8_t version_;
-  uint8_t eh_frame_ptr_encoding_;
-  uint8_t lut_size_encoding_;
-  uint8_t lut_entries_encoding_;
-  int32_t offset_to_eh_frame_;
-  uint32_t lut_entries_number_;
-  int32_t offset_to_procedure_;
-  int32_t offset_to_fde_;
+  static void DumpDwarfDirectives(std::ostream& stream,  // NOLINT
+                                  const byte* start, const byte* end);
+
+  static const char* DwarfRegisterCodeToString(int code);
+
+  const byte* start_;
+  const byte* end_;
+
+  DISALLOW_COPY_AND_ASSIGN(EhFrameDisassembler);
 };
 
+#endif
+
 }  // namespace internal
 }  // namespace v8
 

src/full-codegen/full-codegen.cc

@@ -54,7 +54,7 @@ bool FullCodeGenerator::MakeCode(CompilationInfo* info) {
   }
   unsigned table_offset = cgen.EmitBackEdgeTable();
 
-  Handle<Code> code = CodeGenerator::MakeCodeEpilogue(&masm, info);
+  Handle<Code> code = CodeGenerator::MakeCodeEpilogue(&masm, nullptr, info);
   cgen.PopulateDeoptimizationData(code);
   cgen.PopulateTypeFeedbackInfo(code);
   cgen.PopulateHandlerTable(code);

src/objects.cc

@@ -61,6 +61,7 @@
 #ifdef ENABLE_DISASSEMBLER
 #include "src/disasm.h"
 #include "src/disassembler.h"
+#include "src/eh-frame.h"
 #endif
 
 namespace v8 {
@@ -14372,6 +14373,14 @@ void Code::Disassemble(const char* name, std::ostream& os) {  // NOLINT
     it.rinfo()->Print(GetIsolate(), os);
   }
   os << "\n";
+
+  if (has_unwinding_info()) {
+    os << "UnwindingInfo (size = " << unwinding_info_size() << ")\n";
+    EhFrameDisassembler eh_frame_disassembler(unwinding_info_start(),
+                                              unwinding_info_end());
+    eh_frame_disassembler.DisassembleToStream(os);
+    os << "\n";
+  }
 }
 #endif  // ENABLE_DISASSEMBLER
 

src/perf-jit.cc

@@ -324,18 +324,16 @@ void PerfJitLogger::LogWriteDebugInfo(Code* code, SharedFunctionInfo* shared) {
 }
 
 void PerfJitLogger::LogWriteUnwindingInfo(Code* code) {
-  EhFrameHdr eh_frame_hdr(code);
-
   PerfJitCodeUnwindingInfo unwinding_info_header;
   unwinding_info_header.event_ = PerfJitCodeLoad::kUnwindingInfo;
   unwinding_info_header.time_stamp_ = GetTimestamp();
-  unwinding_info_header.eh_frame_hdr_size_ = EhFrameHdr::kRecordSize;
+  unwinding_info_header.eh_frame_hdr_size_ = EhFrameConstants::kEhFrameHdrSize;
 
   if (code->has_unwinding_info()) {
     unwinding_info_header.unwinding_size_ = code->unwinding_info_size();
     unwinding_info_header.mapped_size_ = unwinding_info_header.unwinding_size_;
   } else {
-    unwinding_info_header.unwinding_size_ = EhFrameHdr::kRecordSize;
+    unwinding_info_header.unwinding_size_ = EhFrameConstants::kEhFrameHdrSize;
     unwinding_info_header.mapped_size_ = 0;
   }
 
@@ -348,16 +346,13 @@ void PerfJitLogger::LogWriteUnwindingInfo(Code* code) {
                 sizeof(unwinding_info_header));
 
   if (code->has_unwinding_info()) {
-    // The last EhFrameHdr::kRecordSize bytes were a placeholder for the header.
-    // Discard them and write the actual eh_frame_hdr (below).
-    DCHECK_GE(code->unwinding_info_size(), EhFrameHdr::kRecordSize);
     LogWriteBytes(reinterpret_cast<const char*>(code->unwinding_info_start()),
-                  code->unwinding_info_size() - EhFrameHdr::kRecordSize);
+                  code->unwinding_info_size());
+  } else {
+    OFStream perf_output_stream(perf_output_handle_);
+    EhFrameWriter::WriteEmptyEhFrame(perf_output_stream);
   }
 
-  LogWriteBytes(reinterpret_cast<const char*>(&eh_frame_hdr),
-                EhFrameHdr::kRecordSize);
-
   char padding_bytes[] = "\0\0\0\0\0\0\0\0";
   DCHECK_LT(padding_size, sizeof(padding_bytes));
   LogWriteBytes(padding_bytes, padding_size);

src/v8.gyp

@@ -1231,6 +1231,7 @@
             'arm/macro-assembler-arm.h',
             'arm/simulator-arm.cc',
             'arm/simulator-arm.h',
+            'arm/eh-frame-arm.cc',
             'compiler/arm/code-generator-arm.cc',
             'compiler/arm/instruction-codes-arm.h',
             'compiler/arm/instruction-scheduler-arm.cc',
@@ -1285,6 +1286,7 @@
             'arm64/simulator-arm64.h',
             'arm64/utils-arm64.cc',
             'arm64/utils-arm64.h',
+            'arm64/eh-frame-arm64.cc',
             'compiler/arm64/code-generator-arm64.cc',
             'compiler/arm64/instruction-codes-arm64.h',
             'compiler/arm64/instruction-scheduler-arm64.cc',
@@ -1514,6 +1516,7 @@
             'compiler/x64/instruction-codes-x64.h',
             'compiler/x64/instruction-scheduler-x64.cc',
             'compiler/x64/instruction-selector-x64.cc',
+            'x64/eh-frame-x64.cc',
           ],
         }],
         ['v8_target_arch=="ppc" or v8_target_arch=="ppc64"', {

src/x64/eh-frame-x64.cc

+// Copyright 2016 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/eh-frame.h"
+
+namespace v8 {
+namespace internal {
+
+static const int kRaxDwarfCode = 0;
+static const int kRbpDwarfCode = 6;
+static const int kRspDwarfCode = 7;
+static const int kRipDwarfCode = 16;
+
+STATIC_CONST_MEMBER_DEFINITION const int
+    EhFrameConstants::kCodeAlignmentFactor = 1;
+
+STATIC_CONST_MEMBER_DEFINITION const int
+    EhFrameConstants::kDataAlignmentFactor = -8;
+
+void EhFrameWriter::WriteReturnAddressRegisterCode() {
+  WriteULeb128(kRipDwarfCode);
+}
+
+void EhFrameWriter::WriteInitialStateInCie() {
+  SetBaseAddressRegisterAndOffset(rsp, kPointerSize);
+  // x64 rip (r16) has no Register instance associated.
+  RecordRegisterSavedToStack(kRipDwarfCode, -kPointerSize);
+}
+
+// static
+int EhFrameWriter::RegisterToDwarfCode(Register name) {
+  switch (name.code()) {
+    case Register::kCode_rbp:
+      return kRbpDwarfCode;
+    case Register::kCode_rsp:
+      return kRspDwarfCode;
+    case Register::kCode_rax:
+      return kRaxDwarfCode;
+    default:
+      UNIMPLEMENTED();
+      return -1;
+  }
+}
+
+#ifdef ENABLE_DISASSEMBLER
+
+// static
+const char* EhFrameDisassembler::DwarfRegisterCodeToString(int code) {
+  switch (code) {
+    case kRbpDwarfCode:
+      return "rbp";
+    case kRspDwarfCode:
+      return "rsp";
+    case kRipDwarfCode:
+      return "rip";
+    default:
+      UNIMPLEMENTED();
+      return nullptr;
+  }
+}
+
+#endif
+
+}  // namespace internal
+}  // namespace v8

test/cctest/cctest.gyp

@@ -138,7 +138,6 @@
       'test-double.cc',
       'test-dtoa.cc',
       'test-elements-kind.cc',
-      'test-eh-frame-hdr.cc',
       'test-fast-dtoa.cc',
       'test-feedback-vector.cc',
       'test-field-type-tracking.cc',

test/cctest/test-eh-frame-hdr.cc

-// Copyright 2016 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/eh-frame.h"
-#include "src/objects.h"
-#include "test/cctest/cctest.h"
-
-using namespace v8::internal;
-
-TEST(EhFrameHdr) {
-  CcTest::InitializeVM();
-  HandleScope handle_scope(CcTest::i_isolate());
-
-  // The content is not relevant in this test
-  byte buffer[10] = {0};
-  byte unwinding_info[30 + EhFrameHdr::kRecordSize] = {0};
-
-  CodeDesc code_desc;
-  code_desc.buffer = &buffer[0];
-  code_desc.buffer_size = sizeof(buffer);
-  code_desc.constant_pool_size = 0;
-  code_desc.instr_size = sizeof(buffer);
-  code_desc.reloc_size = 0;
-  code_desc.origin = nullptr;
-  code_desc.unwinding_info = &unwinding_info[0];
-  code_desc.unwinding_info_size = sizeof(unwinding_info);
-
-  Handle<Code> code = CcTest::i_isolate()->factory()->NewCode(
-      code_desc, 0, Handle<Object>::null());
-
-  EhFrameHdr eh_frame_hdr(*code);
-  CHECK_EQ(eh_frame_hdr.lut_entries_number(), 1);
-
-  //
-  // Plugging some numbers in the DSO layout shown in eh-frame.cc:
-  //
-  //  |      ...      |
-  //  +---------------+ <-- (E) --------
-  //  |               |                ^
-  //  |  Instructions |  10 bytes      | .text
-  //  |               |                v
-  //  +---------------+ <---------------
-  //  |///////////////|
-  //  |////Padding////|   6 bytes
-  //  |///////////////|
-  //  +---------------+ <---(D)---------
-  //  |               |                ^
-  //  |      CIE      |   N bytes*     |
-  //  |               |                |
-  //  +---------------+ <-- (C)        | .eh_frame
-  //  |               |                |
-  //  |      FDE      |  30 - N bytes  |
-  //  |               |                v
-  //  +---------------+ <-- (B) --------
-  //  |    version    |                ^
-  //  +---------------+   4 bytes      |
-  //  |   encoding    |                |
-  //  |  specifiers   |                |
-  //  +---------------+ <---(A)        | .eh_frame_hdr
-  //  |   offset to   |                |
-  //  |   .eh_frame   |                |
-  //  +---------------+                |
-  //  |      ...      |               ...
-  //
-  //  (*) the size of the CIE is platform dependent.
-  //
-  CHECK_EQ(eh_frame_hdr.offset_to_eh_frame(), -(4 + 30));        // A -> D
-  CHECK_EQ(eh_frame_hdr.offset_to_procedure(), -(30 + 6 + 10));  // B -> E
-  CHECK_EQ(eh_frame_hdr.offset_to_fde(),
-           -(30 - EhFrameHdr::kCIESize));  // B -> C
-}
-
-TEST(DummyEhFrameHdr) {
-  CcTest::InitializeVM();
-  HandleScope handle_scope(CcTest::i_isolate());
-
-  byte buffer[10] = {0};  // The content is not relevant in this test
-
-  CodeDesc code_desc;
-  code_desc.buffer = &buffer[0];
-  code_desc.buffer_size = sizeof(buffer);
-  code_desc.constant_pool_size = 0;
-  code_desc.instr_size = sizeof(buffer);
-  code_desc.reloc_size = 0;
-  code_desc.origin = nullptr;
-  code_desc.unwinding_info = nullptr;
-  code_desc.unwinding_info_size = 0;
-
-  Handle<Code> code = CcTest::i_isolate()->factory()->NewCode(
-      code_desc, 0, Handle<Object>::null());
-
-  EhFrameHdr eh_frame_hdr(*code);
-  // A dummy header has an empty LUT
-  CHECK_EQ(eh_frame_hdr.lut_entries_number(), 0);
-  // These values should be irrelevant, but check that they have been zeroed.
-  CHECK_EQ(eh_frame_hdr.offset_to_eh_frame(), 0);
-  CHECK_EQ(eh_frame_hdr.offset_to_procedure(), 0);
-  CHECK_EQ(eh_frame_hdr.offset_to_fde(), 0);
-}

test/unittests/eh-frame-iterator-unittest.cc

+// Copyright 2016 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/eh-frame.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+// Test enabled only on supported architectures.
+#if defined(V8_TARGET_ARCH_X64) || defined(V8_TARGET_ARCH_ARM) || \
+    defined(V8_TARGET_ARCH_ARM64)
+
+using namespace v8::internal;
+
+namespace {
+
+class EhFrameIteratorTest : public testing::Test {};
+
+}  // namespace
+
+TEST_F(EhFrameIteratorTest, Values) {
+  // Assuming little endian.
+  static const byte kEncoded[] = {0xde, 0xc0, 0xad, 0xde, 0xef, 0xbe, 0xff};
+  EhFrameIterator iterator(&kEncoded[0], &kEncoded[0] + sizeof(kEncoded));
+  EXPECT_EQ(0xdeadc0de, iterator.GetNextUInt32());
+  EXPECT_EQ(0xbeef, iterator.GetNextUInt16());
+  EXPECT_EQ(0xff, iterator.GetNextByte());
+  EXPECT_TRUE(iterator.Done());
+}
+
+TEST_F(EhFrameIteratorTest, Skip) {
+  static const byte kEncoded[] = {0xde, 0xad, 0xc0, 0xde};
+  EhFrameIterator iterator(&kEncoded[0], &kEncoded[0] + sizeof(kEncoded));
+  iterator.Skip(2);
+  EXPECT_EQ(2, iterator.GetCurrentOffset());
+  EXPECT_EQ(0xc0, iterator.GetNextByte());
+  iterator.Skip(1);
+  EXPECT_TRUE(iterator.Done());
+}
+
+TEST_F(EhFrameIteratorTest, ULEB128Decoding) {
+  static const byte kEncoded[] = {0xe5, 0x8e, 0x26};
+  EhFrameIterator iterator(&kEncoded[0], &kEncoded[0] + sizeof(kEncoded));
+  EXPECT_EQ(624485, iterator.GetNextULeb128());
+  EXPECT_TRUE(iterator.Done());
+}
+
+TEST_F(EhFrameIteratorTest, SLEB128DecodingPositive) {
+  static const byte kEncoded[] = {0xe5, 0x8e, 0x26};
+  EhFrameIterator iterator(&kEncoded[0], &kEncoded[0] + sizeof(kEncoded));
+  EXPECT_EQ(624485, iterator.GetNextSLeb128());
+  EXPECT_TRUE(iterator.Done());
+}
+
+TEST_F(EhFrameIteratorTest, SLEB128DecodingNegative) {
+  static const byte kEncoded[] = {0x9b, 0xf1, 0x59};
+  EhFrameIterator iterator(&kEncoded[0], &kEncoded[0] + sizeof(kEncoded));
+  EXPECT_EQ(-624485, iterator.GetNextSLeb128());
+  EXPECT_TRUE(iterator.Done());
+}
+
+#endif

test/unittests/unittests.gyp

@@ -79,6 +79,8 @@
       'compiler/value-numbering-reducer-unittest.cc',
       'compiler/zone-pool-unittest.cc',
       'counters-unittest.cc',
+      'eh-frame-iterator-unittest.cc',
+      'eh-frame-writer-unittest.cc',
       'interpreter/bytecodes-unittest.cc',
       'interpreter/bytecode-array-builder-unittest.cc',
       'interpreter/bytecode-array-iterator-unittest.cc',