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 "test/unittests/test-utils.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 EhFrameWriterTest : public TestWithZone {
+ protected:
+  // Being a 7bit positive integer, this also serves as its ULEB128 encoding.
+  static const int kTestRegisterCode = 0;
+
+  static EhFrameIterator MakeIterator(EhFrameWriter* writer) {
+    CodeDesc desc;
+    writer->GetEhFrame(&desc);
+    DCHECK_GT(desc.unwinding_info_size, 0);
+    return EhFrameIterator(desc.unwinding_info,
+                           desc.unwinding_info + desc.unwinding_info_size);
+  }
+};
+
+const int EhFrameWriterTest::kTestRegisterCode;
+
+}  // namespace
+
+TEST_F(EhFrameWriterTest, Alignment) {
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.AdvanceLocation(42 * EhFrameConstants::kCodeAlignmentFactor);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  ASSERT_EQ(0, EhFrameConstants::kEhFrameHdrSize % 4);
+  ASSERT_EQ(0, EhFrameConstants::kEhFrameTerminatorSize % 4);
+  EXPECT_EQ(0, (iterator.GetBufferSize() - EhFrameConstants::kEhFrameHdrSize -
+                EhFrameConstants::kEhFrameTerminatorSize) %
+                   8);
+}
+
+TEST_F(EhFrameWriterTest, FDEHeader) {
+  static const int kProcedureSize = 0x5678abcd;
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.Finish(kProcedureSize);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  int cie_size = iterator.GetNextUInt32();
+  iterator.Skip(cie_size);
+
+  int fde_size = iterator.GetNextUInt32();
+  EXPECT_EQ(iterator.GetBufferSize(),
+            fde_size + cie_size + EhFrameConstants::kEhFrameTerminatorSize +
+                EhFrameConstants::kEhFrameHdrSize + 2 * kInt32Size);
+
+  int backwards_offset_to_cie_offset = iterator.GetCurrentOffset();
+  int backwards_offset_to_cie = iterator.GetNextUInt32();
+  EXPECT_EQ(backwards_offset_to_cie_offset, backwards_offset_to_cie);
+
+  int procedure_address_offset = iterator.GetCurrentOffset();
+  int procedure_address = iterator.GetNextUInt32();
+  EXPECT_EQ(-(procedure_address_offset + RoundUp(kProcedureSize, 8)),
+            procedure_address);
+
+  int procedure_size = iterator.GetNextUInt32();
+  EXPECT_EQ(kProcedureSize, procedure_size);
+}
+
+TEST_F(EhFrameWriterTest, SetOffset) {
+  static const int kOffset = 0x0badc0de;
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.SetBaseAddressOffset(kOffset);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ(EhFrameConstants::DwarfOpcodes::kDefCfaOffset,
+            iterator.GetNextOpcode());
+  EXPECT_EQ(kOffset, iterator.GetNextULeb128());
+}
+
+TEST_F(EhFrameWriterTest, IncreaseOffset) {
+  static const int kFirstOffset = 121;
+  static const int kSecondOffset = 16;
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.SetBaseAddressOffset(kFirstOffset);
+  writer.IncreaseBaseAddressOffset(kSecondOffset);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ(EhFrameConstants::DwarfOpcodes::kDefCfaOffset,
+            iterator.GetNextOpcode());
+  EXPECT_EQ(kFirstOffset, iterator.GetNextULeb128());
+
+  EXPECT_EQ(EhFrameConstants::DwarfOpcodes::kDefCfaOffset,
+            iterator.GetNextOpcode());
+  EXPECT_EQ(kFirstOffset + kSecondOffset, iterator.GetNextULeb128());
+}
+
+TEST_F(EhFrameWriterTest, SetRegister) {
+  Register test_register = Register::from_code(kTestRegisterCode);
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.SetBaseAddressRegister(test_register);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ(EhFrameConstants::DwarfOpcodes::kDefCfaRegister,
+            iterator.GetNextOpcode());
+  EXPECT_EQ(kTestRegisterCode, iterator.GetNextULeb128());
+}
+
+TEST_F(EhFrameWriterTest, SetRegisterAndOffset) {
+  Register test_register = Register::from_code(kTestRegisterCode);
+  static const int kOffset = 0x0badc0de;
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.SetBaseAddressRegisterAndOffset(test_register, kOffset);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ(EhFrameConstants::DwarfOpcodes::kDefCfa, iterator.GetNextOpcode());
+  EXPECT_EQ(kTestRegisterCode, iterator.GetNextULeb128());
+  EXPECT_EQ(kOffset, iterator.GetNextULeb128());
+}
+
+TEST_F(EhFrameWriterTest, PcOffsetEncoding6bit) {
+  static const int kOffset = 42;
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.AdvanceLocation(kOffset * EhFrameConstants::kCodeAlignmentFactor);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ((1 << 6) | kOffset, iterator.GetNextByte());
+}
+
+TEST_F(EhFrameWriterTest, PcOffsetEncoding6bitDelta) {
+  static const int kFirstOffset = 42;
+  static const int kSecondOffset = 62;
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.AdvanceLocation(kFirstOffset * EhFrameConstants::kCodeAlignmentFactor);
+  writer.AdvanceLocation(kSecondOffset *
+                         EhFrameConstants::kCodeAlignmentFactor);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ((1 << 6) | kFirstOffset, iterator.GetNextByte());
+  EXPECT_EQ((1 << 6) | (kSecondOffset - kFirstOffset), iterator.GetNextByte());
+}
+
+TEST_F(EhFrameWriterTest, PcOffsetEncoding8bit) {
+  static const int kOffset = 0x42;
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.AdvanceLocation(kOffset * EhFrameConstants::kCodeAlignmentFactor);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ(EhFrameConstants::DwarfOpcodes::kAdvanceLoc1,
+            iterator.GetNextOpcode());
+  EXPECT_EQ(kOffset, iterator.GetNextByte());
+}
+
+TEST_F(EhFrameWriterTest, PcOffsetEncoding8bitDelta) {
+  static const int kFirstOffset = 0x10;
+  static const int kSecondOffset = 0x70;
+  static const int kThirdOffset = 0xb5;
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.AdvanceLocation(kFirstOffset * EhFrameConstants::kCodeAlignmentFactor);
+  writer.AdvanceLocation(kSecondOffset *
+                         EhFrameConstants::kCodeAlignmentFactor);
+  writer.AdvanceLocation(kThirdOffset * EhFrameConstants::kCodeAlignmentFactor);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ((1 << 6) | kFirstOffset, iterator.GetNextByte());
+
+  EXPECT_EQ(EhFrameConstants::DwarfOpcodes::kAdvanceLoc1,
+            iterator.GetNextOpcode());
+  EXPECT_EQ(kSecondOffset - kFirstOffset, iterator.GetNextByte());
+
+  EXPECT_EQ(EhFrameConstants::DwarfOpcodes::kAdvanceLoc1,
+            iterator.GetNextOpcode());
+  EXPECT_EQ(kThirdOffset - kSecondOffset, iterator.GetNextByte());
+}
+
+TEST_F(EhFrameWriterTest, PcOffsetEncoding16bit) {
+  static const int kOffset = kMaxUInt8 + 42;
+  ASSERT_LT(kOffset, kMaxUInt16);
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.AdvanceLocation(kOffset * EhFrameConstants::kCodeAlignmentFactor);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ(EhFrameConstants::DwarfOpcodes::kAdvanceLoc2,
+            iterator.GetNextOpcode());
+  EXPECT_EQ(kOffset, iterator.GetNextUInt16());
+}
+
+TEST_F(EhFrameWriterTest, PcOffsetEncoding16bitDelta) {
+  static const int kFirstOffset = 0x41;
+  static const int kSecondOffset = kMaxUInt8 + 0x42;
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.AdvanceLocation(kFirstOffset * EhFrameConstants::kCodeAlignmentFactor);
+  writer.AdvanceLocation(kSecondOffset *
+                         EhFrameConstants::kCodeAlignmentFactor);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ(EhFrameConstants::DwarfOpcodes::kAdvanceLoc1,
+            iterator.GetNextOpcode());
+  EXPECT_EQ(kFirstOffset, iterator.GetNextByte());
+
+  EXPECT_EQ(EhFrameConstants::DwarfOpcodes::kAdvanceLoc2,
+            iterator.GetNextOpcode());
+  EXPECT_EQ(kSecondOffset - kFirstOffset, iterator.GetNextUInt16());
+}
+
+TEST_F(EhFrameWriterTest, PcOffsetEncoding32bit) {
+  static const int kOffset = kMaxUInt16 + 42;
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.AdvanceLocation(kOffset * EhFrameConstants::kCodeAlignmentFactor);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ(EhFrameConstants::DwarfOpcodes::kAdvanceLoc4,
+            iterator.GetNextOpcode());
+  EXPECT_EQ(kOffset, iterator.GetNextUInt32());
+}
+
+TEST_F(EhFrameWriterTest, PcOffsetEncoding32bitDelta) {
+  static const int kFirstOffset = kMaxUInt16 + 0x42;
+  static const int kSecondOffset = kMaxUInt16 + 0x67;
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.AdvanceLocation(kFirstOffset * EhFrameConstants::kCodeAlignmentFactor);
+  writer.AdvanceLocation(kSecondOffset *
+                         EhFrameConstants::kCodeAlignmentFactor);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ(EhFrameConstants::DwarfOpcodes::kAdvanceLoc4,
+            iterator.GetNextOpcode());
+  EXPECT_EQ(kFirstOffset, iterator.GetNextUInt32());
+
+  EXPECT_EQ((1 << 6) | (kSecondOffset - kFirstOffset), iterator.GetNextByte());
+}
+
+TEST_F(EhFrameWriterTest, SaveRegisterUnsignedOffset) {
+  Register test_register = Register::from_code(kTestRegisterCode);
+  static const int kOffset =
+      EhFrameConstants::kDataAlignmentFactor > 0 ? 12344 : -12344;
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.RecordRegisterSavedToStack(test_register, kOffset);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ((2 << 6) | kTestRegisterCode, iterator.GetNextByte());
+  EXPECT_EQ(kOffset / EhFrameConstants::kDataAlignmentFactor,
+            iterator.GetNextULeb128());
+}
+
+TEST_F(EhFrameWriterTest, SaveRegisterSignedOffset) {
+  Register test_register = Register::from_code(kTestRegisterCode);
+  static const int kOffset =
+      EhFrameConstants::kDataAlignmentFactor < 0 ? 12344 : -12344;
+
+  ASSERT_EQ(kOffset % EhFrameConstants::kDataAlignmentFactor, 0);
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.RecordRegisterSavedToStack(test_register, kOffset);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ(EhFrameConstants::DwarfOpcodes::kOffsetExtendedSf,
+            iterator.GetNextOpcode());
+  EXPECT_EQ(kTestRegisterCode, iterator.GetNextULeb128());
+  EXPECT_EQ(kOffset / EhFrameConstants::kDataAlignmentFactor,
+            iterator.GetNextSLeb128());
+}
+
+TEST_F(EhFrameWriterTest, RegisterNotModified) {
+  Register test_register = Register::from_code(kTestRegisterCode);
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.RecordRegisterNotModified(test_register);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ(EhFrameConstants::DwarfOpcodes::kSameValue,
+            iterator.GetNextOpcode());
+  EXPECT_EQ(kTestRegisterCode, iterator.GetNextULeb128());
+}
+
+TEST_F(EhFrameWriterTest, RegisterFollowsInitialRule) {
+  Register test_register = Register::from_code(kTestRegisterCode);
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.RecordRegisterFollowsInitialRule(test_register);
+  writer.Finish(100);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+  iterator.SkipToFdeDirectives();
+
+  EXPECT_EQ((3 << 6) | kTestRegisterCode, iterator.GetNextByte());
+}
+
+TEST_F(EhFrameWriterTest, EhFrameHdrLayout) {
+  static const int kCodeSize = 10;
+  static const int kPaddingSize = 6;
+
+  EhFrameWriter writer(zone());
+  writer.Initialize();
+  writer.Finish(kCodeSize);
+
+  EhFrameIterator iterator = MakeIterator(&writer);
+
+  // Skip the .eh_frame.
+
+  int encoded_cie_size = iterator.GetNextUInt32();
+  iterator.Skip(encoded_cie_size);
+  int cie_size = encoded_cie_size + kInt32Size;
+
+  int encoded_fde_size = iterator.GetNextUInt32();
+  iterator.Skip(encoded_fde_size);
+  int fde_size = encoded_fde_size + kInt32Size;
+
+  iterator.Skip(EhFrameConstants::kEhFrameTerminatorSize);
+
+  int eh_frame_size =
+      cie_size + fde_size + EhFrameConstants::kEhFrameTerminatorSize;
+
+  //
+  // Plugging some numbers in the DSO layout shown in eh-frame.cc:
+  //
+  //  |      ...      |
+  //  +---------------+ <-- (E) ---------
+  //  |               |                 ^
+  //  |  Instructions |  10 bytes       | .text
+  //  |               |                 v
+  //  +---------------+ <----------------
+  //  |///////////////|
+  //  |////Padding////|   6 bytes
+  //  |///////////////|
+  //  +---------------+ <---(D)----------
+  //  |               |                 ^
+  //  |      CIE      | cie_size bytes* |
+  //  |               |                 |
+  //  +---------------+ <-- (C)         |
+  //  |               |                 | .eh_frame
+  //  |      FDE      | fde_size bytes  |
+  //  |               |                 |
+  //  +---------------+                 |
+  //  |   terminator  |   4 bytes       v
+  //  +---------------+ <-- (B) ---------
+  //  |    version    |                 ^
+  //  +---------------+   4 bytes       |
+  //  |   encoding    |                 |
+  //  |  specifiers   |                 |
+  //  +---------------+ <---(A)         | .eh_frame_hdr
+  //  |   offset to   |                 |
+  //  |   .eh_frame   |                 |
+  //  +---------------+                 |
+  //  |      ...      |                ...
+  //
+  //  (*) the size of the CIE is platform dependent.
+  //
+
+  int eh_frame_hdr_version = iterator.GetNextByte();
+  EXPECT_EQ(EhFrameConstants::kEhFrameHdrVersion, eh_frame_hdr_version);
+
+  // .eh_frame pointer encoding specifier.
+  EXPECT_EQ(EhFrameConstants::kSData4 | EhFrameConstants::kPcRel,
+            iterator.GetNextByte());
+
+  // Lookup table size encoding specifier.
+  EXPECT_EQ(EhFrameConstants::kUData4, iterator.GetNextByte());
+
+  // Lookup table pointers encoding specifier.
+  EXPECT_EQ(EhFrameConstants::kSData4 | EhFrameConstants::kDataRel,
+            iterator.GetNextByte());
+
+  // A -> D
+  int offset_to_eh_frame = iterator.GetNextUInt32();
+  EXPECT_EQ(-(EhFrameConstants::kFdeVersionSize +
+              EhFrameConstants::kFdeEncodingSpecifiersSize + eh_frame_size),
+            offset_to_eh_frame);
+
+  int lut_entries = iterator.GetNextUInt32();
+  EXPECT_EQ(1, lut_entries);
+
+  // B -> E
+  int offset_to_procedure = iterator.GetNextUInt32();
+  EXPECT_EQ(-(eh_frame_size + kPaddingSize + kCodeSize), offset_to_procedure);
+
+  // B -> C
+  int offset_to_fde = iterator.GetNextUInt32();
+  EXPECT_EQ(-(fde_size + EhFrameConstants::kEhFrameTerminatorSize),
+            offset_to_fde);
+}
+
+#endif