Reland Implement .eh_frame writer and disassembler.

test/unittests/eh-frame-writer-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 v8 {
+namespace internal {
+
+class EhFrameWriterInternals : public testing::Test {
+ protected:
+  // Being a non-negative 6bit value, this also serves as its LEB128 encoding.
+  static const int kTestRegisterCode = 0;

[rmcilroy, 2016/07/05 10:56:13]

I would test a more interesting code than '0', that doesn't really check the
encoding is correct

+
+  void WriteULEB128(int value) { writer_.WriteULEB128(value); }
+  void WriteSLEB128(int value) { writer_.WriteSLEB128(value); }
+  void Align() { writer_.Align(); }
+  void WriteByte(byte c) { writer_.WriteByte(c); }
+
+  static uint32_t DecodeULEB128(const byte* data, int* decoded_size) {
+    return EhFrameWriter::DecodeULEB128(data, decoded_size);
+  }
+
+  static int32_t DecodeSLEB128(const byte* data, int* decoded_size) {
+    return EhFrameWriter::DecodeSLEB128(data, decoded_size);
+  }
+
+  byte* eh_frame_buffer() { return writer_.eh_frame_buffer_.data(); }
+  int eh_frame_offset() const { return writer_.eh_frame_offset(); }
+  int cie_size() const { return writer_.cie_size_; }
+  int fde_offset() const { return writer_.fde_offset(); }
+  int procedure_address_offset() const {
+    return writer_.procedure_address_offset();
+  }
+  int procedure_size_offset() const { return writer_.procedure_size_offset(); }
+
+  EhFrameWriter writer_;
+};
+
+STATIC_CONST_MEMBER_DEFINITION const int
+    EhFrameWriterInternals::kTestRegisterCode;

[rmcilroy, 2016/07/05 10:56:13]

Don't think you should need this?

[Stefano Sanfilippo, 2016/07/05 16:02:14]

Also in this case, omitting this bit results in a linking error.

+
+}  // namespace internal
+}  // namespace v8
+
+TEST_F(EhFrameWriterInternals, RecordsAlignment) {

[rmcilroy, 2016/07/05 10:56:13]

The fixture should be named EhFrameWriterTest

[Stefano Sanfilippo, 2016/07/05 16:02:14]

Done.

+  writer_.Finish(100);
+  EXPECT_EQ(4, EhFrameWriter::kTerminatorSize);
+  EXPECT_EQ(0, EhFrameHdr::kRecordSize % 4);
+  EXPECT_EQ(0, (eh_frame_offset() - EhFrameHdr::kRecordSize -
+                EhFrameWriter::kTerminatorSize) %
+                   8);
+}
+
+TEST_F(EhFrameWriterInternals, Align) {
+  // Ensure the buffer size is not already aligned.
+  if (eh_frame_offset() % 8 == 0) WriteByte(0);
+  Align();
+  EXPECT_EQ(eh_frame_offset() % 8, 0);
+}
+
+TEST_F(EhFrameWriterInternals, AlignNop) {
+  Align();
+  int first_size = eh_frame_offset();
+  // This second align should result in a nop
+  Align();
+  int second_size = eh_frame_offset();
+  EXPECT_EQ(first_size, second_size);
+}
+
+TEST_F(EhFrameWriterInternals, ProcedureBoundaries) {
+  writer_.Finish(100);
+  int32_t procedure_offset =
+      ReadUnalignedUInt32(eh_frame_buffer() + procedure_address_offset());
+  EXPECT_EQ(-(procedure_address_offset() + RoundUp(100, 8)), procedure_offset);
+  uint32_t procedure_size =
+      ReadUnalignedUInt32(eh_frame_buffer() + procedure_size_offset());
+  EXPECT_EQ(100, procedure_size);
+}
+
+TEST_F(EhFrameWriterInternals, CIESize) {
+  writer_.Finish(42);
+  uint32_t encoded_cie_size = ReadUnalignedUInt32(eh_frame_buffer());
+  // The encoded CIE size does not include the size field itself.
+  EXPECT_EQ(cie_size(), encoded_cie_size + kInt32Size);
+}
+
+TEST_F(EhFrameWriterInternals, FDESize) {
+  writer_.Finish(42);
+  uint32_t fde_size = ReadUnalignedUInt32(eh_frame_buffer() + fde_offset());
+  EXPECT_EQ(eh_frame_offset() - EhFrameHdr::kRecordSize - cie_size() -
+                EhFrameWriter::kTerminatorSize,
+            fde_size);
+}
+
+TEST_F(EhFrameWriterInternals, SetOffset) {
+  Register base_register_before_update = writer_.base_register();
+  int start = eh_frame_offset();
+  writer_.SetBaseAddressOffset(64);
+  int end = eh_frame_offset();
+  EXPECT_EQ(64, writer_.base_offset());
+  EXPECT_TRUE(base_register_before_update.is(writer_.base_register()));
+  EXPECT_EQ(2, end - start);
+  EXPECT_EQ(EhFrameWriter::kDefCfaOffset, eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(64, eh_frame_buffer()[start + 1]);
+}
+
+TEST_F(EhFrameWriterInternals, IncreaseOffset) {
+  int base_offset_before_update = writer_.base_offset();
+  Register base_register_before_update = writer_.base_register();
+  int start = eh_frame_offset();
+  writer_.IncreaseBaseAddressOffset(16);
+  int end = eh_frame_offset();
+  EXPECT_EQ(base_offset_before_update + 16, writer_.base_offset());
+  EXPECT_TRUE(base_register_before_update.is(writer_.base_register()));
+  EXPECT_EQ(2, end - start);
+  EXPECT_EQ(EhFrameWriter::kDefCfaOffset, eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(base_offset_before_update + 16, eh_frame_buffer()[start + 1]);
+}
+
+TEST_F(EhFrameWriterInternals, SetRegister) {
+  int base_offset_before_update = writer_.base_offset();
+  int start = eh_frame_offset();
+  Register test_register = Register::from_code(kTestRegisterCode);
+  writer_.SetBaseAddressRegister(test_register);
+  int end = eh_frame_offset();
+  EXPECT_TRUE(writer_.base_register().is(test_register));
+  EXPECT_EQ(base_offset_before_update, writer_.base_offset());
+  EXPECT_EQ(2, end - start);
+  EXPECT_EQ(EhFrameWriter::kDefCfaRegister, eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(kTestRegisterCode, eh_frame_buffer()[start + 1]);
+}
+
+TEST_F(EhFrameWriterInternals, SetRegisterAndOffset) {
+  int start = eh_frame_offset();
+  Register test_register = Register::from_code(0);
+  writer_.SetBaseAddressRegisterAndOffset(test_register, 24);
+  int end = eh_frame_offset();
+  EXPECT_EQ(24, writer_.base_offset());
+  EXPECT_TRUE(writer_.base_register().is(test_register));
+  EXPECT_EQ(3, end - start);
+  EXPECT_EQ(EhFrameWriter::kDefCfa, eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(kTestRegisterCode, eh_frame_buffer()[start + 1]);
+  EXPECT_EQ(24, eh_frame_buffer()[start + 2]);
+}
+
+TEST_F(EhFrameWriterInternals, ULEB128Encoding) {
+  int start = eh_frame_offset();
+  WriteULEB128(624485);
+  int end = eh_frame_offset();
+  static const byte kExpectedEncoding[] = {0xe5, 0x8e, 0x26};
+
+  EXPECT_EQ(sizeof(kExpectedEncoding), end - start);
+  EXPECT_EQ(kExpectedEncoding[0], eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(kExpectedEncoding[1], eh_frame_buffer()[start + 1]);
+  EXPECT_EQ(kExpectedEncoding[2], eh_frame_buffer()[start + 2]);
+}
+
+TEST_F(EhFrameWriterInternals, SLEB128EncodingPositive) {
+  int start = eh_frame_offset();
+  WriteSLEB128(624485);
+  int end = eh_frame_offset();
+  static const byte kExpectedEncoding[] = {0xe5, 0x8e, 0x26};
+
+  EXPECT_EQ(sizeof(kExpectedEncoding), end - start);
+  EXPECT_EQ(kExpectedEncoding[0], eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(kExpectedEncoding[1], eh_frame_buffer()[start + 1]);
+  EXPECT_EQ(kExpectedEncoding[2], eh_frame_buffer()[start + 2]);
+}
+
+TEST_F(EhFrameWriterInternals, SLEB128EncodingNegative) {
+  int start = eh_frame_offset();
+  WriteSLEB128(-624485);
+  int end = eh_frame_offset();
+  static const byte kExpectedEncoding[] = {0x9b, 0xf1, 0x59};
+
+  EXPECT_EQ(sizeof(kExpectedEncoding), end - start);
+  EXPECT_EQ(kExpectedEncoding[0], eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(kExpectedEncoding[1], eh_frame_buffer()[start + 1]);
+  EXPECT_EQ(kExpectedEncoding[2], eh_frame_buffer()[start + 2]);
+}
+
+TEST_F(EhFrameWriterInternals, ULEB128Decoding) {
+  static const byte kEncoded[] = {0xe5, 0x8e, 0x26};
+  int size = 0;
+  uint32_t value = DecodeULEB128(kEncoded, &size);
+  EXPECT_EQ(static_cast<int>(sizeof(kEncoded)), size);
+  EXPECT_EQ(624485, value);
+}
+
+TEST_F(EhFrameWriterInternals, SLEB128DecodingPositive) {
+  static const byte kEncoded[] = {0xe5, 0x8e, 0x26};
+  int size = 0;
+  int32_t value = DecodeSLEB128(kEncoded, &size);
+  EXPECT_EQ(static_cast<int>(sizeof(kEncoded)), size);
+  EXPECT_EQ(624485, value);
+}
+
+TEST_F(EhFrameWriterInternals, SLEB128DecodingNegative) {
+  static const byte kEncoded[] = {0x9b, 0xf1, 0x59};
+  int size = 0;
+  int32_t value = DecodeSLEB128(kEncoded, &size);
+  EXPECT_EQ(static_cast<int>(sizeof(kEncoded)), size);
+  EXPECT_EQ(-624485, value);
+}
+
+TEST_F(EhFrameWriterInternals, PcOffsetEncoding6bit) {
+  EXPECT_EQ(0, writer_.last_pc_offset());
+  int start = eh_frame_offset();
+  writer_.AdvanceLocation(42);
+  int end = eh_frame_offset();
+  EXPECT_EQ(1, end - start);
+  EXPECT_EQ((1 << 6) | 42, eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(42, writer_.last_pc_offset());
+}
+
+TEST_F(EhFrameWriterInternals, PcOffsetEncoding6bitDelta) {
+  writer_.AdvanceLocation(42);
+  int start = eh_frame_offset();
+  writer_.AdvanceLocation(65);
+  int end = eh_frame_offset();
+  EXPECT_EQ(1, end - start);
+  EXPECT_EQ((1 << 6) | (65 - 42), eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(65, writer_.last_pc_offset());
+}
+
+TEST_F(EhFrameWriterInternals, PcOffsetEncoding8bit) {
+  EXPECT_EQ(0, writer_.last_pc_offset());
+  int start = eh_frame_offset();
+  writer_.AdvanceLocation(0x42);
+  int end = eh_frame_offset();
+  EXPECT_EQ(1 + sizeof(uint8_t), end - start);
+  EXPECT_EQ(EhFrameWriter::kAdvanceLoc1, eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(0x42, eh_frame_buffer()[start + 1]);
+  EXPECT_EQ(0x42, writer_.last_pc_offset());
+}
+
+TEST_F(EhFrameWriterInternals, PcOffsetEncoding8bitDelta) {
+  writer_.AdvanceLocation(0x10);
+  int start = eh_frame_offset();
+  writer_.AdvanceLocation(0x70);
+  int end = eh_frame_offset();
+  EXPECT_EQ(1 + sizeof(uint8_t), end - start);
+  EXPECT_EQ(0x70 - 0x10, eh_frame_buffer()[start + 1]);
+  EXPECT_EQ(0x70, writer_.last_pc_offset());
+}
+
+TEST_F(EhFrameWriterInternals, PcOffsetEncoding16bit) {
+  EXPECT_EQ(0, writer_.last_pc_offset());
+  int start = eh_frame_offset();
+  writer_.AdvanceLocation(42 + kMaxUInt8);
+  int end = eh_frame_offset();
+  EXPECT_EQ(1 + sizeof(uint16_t), end - start);
+  EXPECT_EQ(EhFrameWriter::kAdvanceLoc2, eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(42 + kMaxUInt8, ReadUnalignedUInt16(eh_frame_buffer() + start + 1));
+  EXPECT_EQ(42 + kMaxUInt8, writer_.last_pc_offset());
+}
+
+TEST_F(EhFrameWriterInternals, PcOffsetEncoding16bitDelta) {
+  writer_.AdvanceLocation(41);
+  int start = eh_frame_offset();
+  writer_.AdvanceLocation(62 + kMaxUInt8);
+  int end = eh_frame_offset();
+  EXPECT_EQ(1 + sizeof(uint16_t), end - start);
+  EXPECT_EQ(62 + kMaxUInt8 - 41,
+            ReadUnalignedUInt16(eh_frame_buffer() + start + 1));
+  EXPECT_EQ(62 + kMaxUInt8, writer_.last_pc_offset());
+}
+
+TEST_F(EhFrameWriterInternals, PcOffsetEncoding32bit) {
+  EXPECT_EQ(0, writer_.last_pc_offset());
+  int start = eh_frame_offset();
+  writer_.AdvanceLocation(42 + kMaxUInt16);
+  int end = eh_frame_offset();
+  EXPECT_EQ(1 + sizeof(uint32_t), end - start);
+  EXPECT_EQ(EhFrameWriter::kAdvanceLoc4, eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(42 + kMaxUInt16,
+            ReadUnalignedUInt32(eh_frame_buffer() + start + 1));
+  EXPECT_EQ(42 + kMaxUInt16, writer_.last_pc_offset());
+}
+
+TEST_F(EhFrameWriterInternals, PcOffsetEncoding32bitDelta) {
+  writer_.AdvanceLocation(41);
+  int start = eh_frame_offset();
+  writer_.AdvanceLocation(62 + kMaxUInt16);
+  int end = eh_frame_offset();
+  EXPECT_EQ(1 + sizeof(uint32_t), end - start);
+  EXPECT_EQ(62 + kMaxUInt16 - 41,
+            ReadUnalignedUInt32(eh_frame_buffer() + start + 1));
+  EXPECT_EQ(62 + kMaxUInt16, writer_.last_pc_offset());
+}
+
+TEST_F(EhFrameWriterInternals, GetEhFrame) {
+  writer_.Finish(42);
+  CodeDesc code_desc;
+  writer_.GetEhFrame(&code_desc);
+  EXPECT_EQ(eh_frame_offset(), code_desc.unwinding_info_size);
+  EXPECT_EQ(0, memcmp(eh_frame_buffer(), code_desc.unwinding_info,
+                      eh_frame_offset()));
+}
+
+TEST_F(EhFrameWriterInternals, SaveRegisterPositiveOffset) {
+  int start = eh_frame_offset();
+  Register test_register = Register::from_code(kTestRegisterCode);
+  writer_.RegisterSavedToStack(test_register, 16);
+  int end = eh_frame_offset();
+  EXPECT_EQ(2, end - start);
+  EXPECT_EQ((2 << 6) | kTestRegisterCode, eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(16 / std::abs(EhFrameWriter::kDataAlignmentFactor),
+            eh_frame_buffer()[start + 1]);
+}
+
+TEST_F(EhFrameWriterInternals, SaveRegisterNegativeOffset) {
+  int start = eh_frame_offset();
+  Register test_register = Register::from_code(kTestRegisterCode);
+  writer_.RegisterSavedToStack(test_register, -16);
+  int end = eh_frame_offset();
+  EXPECT_EQ(3, end - start);
+  EXPECT_EQ(EhFrameWriter::kOffsetExtendedSf, eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(kTestRegisterCode, eh_frame_buffer()[start + 1]);
+  if (EhFrameWriter::kDataAlignmentFactor == -4) {
+    EXPECT_EQ(0x7c, eh_frame_buffer()[start + 2]);  // -4 SLEB128 encoded.
+  } else if (EhFrameWriter::kDataAlignmentFactor == -8) {
+    EXPECT_EQ(0x7e, eh_frame_buffer()[start + 2]);  // -2 SLEB128 encoded.
+  } else {
+    EXPECT_TRUE(false && "Data alignment not handled in test.");
+  }
+}
+
+TEST_F(EhFrameWriterInternals, SaveRegisterToTop) {
+  int base_offset_before_call = writer_.base_offset();
+  int start = eh_frame_offset();
+  Register test_register = Register::from_code(kTestRegisterCode);
+  writer_.RegisterSavedToStack(test_register);
+  int end = eh_frame_offset();
+  EXPECT_EQ(base_offset_before_call, writer_.base_offset());
+  EXPECT_GE(base_offset_before_call, 0);
+  EXPECT_EQ(2, end - start);
+  EXPECT_EQ((2 << 6) | kTestRegisterCode, eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(
+      base_offset_before_call / std::abs(EhFrameWriter::kDataAlignmentFactor),
+      eh_frame_buffer()[start + 1]);
+}
+
+TEST_F(EhFrameWriterInternals, RegisterIsValid) {
+  Register test_register = Register::from_code(kTestRegisterCode);
+  int start = eh_frame_offset();
+  writer_.RegisterIsValid(test_register);
+  int end = eh_frame_offset();
+  EXPECT_EQ(2, end - start);
+  EXPECT_EQ(EhFrameWriter::kSameValue, eh_frame_buffer()[start + 0]);
+  EXPECT_EQ(kTestRegisterCode, eh_frame_buffer()[start + 1]);
+}
+
+#endif