[Zucchini] Disassemblers: Fix abs32 width for ELF; cleanup Traits template param.

Previously DisassemblerElfIntel<TRAITS>::ParseExecSection() passes a
hard-coded 4 to Abs32GapFinder's |abs32_width| CTOR param. This is
wrong for X64, which has abs32 pointer width of 8 bytes. This can lead
to lower quality rel32 extraction.

This CL fixes the above by replacing 4 with Traits::kVAWidth, and also
cleans up TRAITS / Traits template parameter for Disassembler:
* For template param, "template <class TRAITS>" is used throughout.
  * This means function params needs to use TRAITS.
* For usage, each Disassembler class with TRAITS declares
    using Traits = TRAITS;
  (and variant) and uses Traits in the body of all functions. Reason:
  Specialized derive classes won't have TRAITS available , so:
  * Function params can use DisassemblerBase::Traits.
  * Function bodies can use Traits.
  * For consistency, even if TRAITS is available, still use Traits.

Bug: 1233831
Change-Id: Ie796c867fb238eca462b2fb6b4e68a965996c25a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3063919
Commit-Queue: Samuel Huang <huangs@chromium.org>
Reviewed-by: Etienne Pierre-Doray <etiennep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#908261}
NOKEYCHECK=True
GitOrigin-RevId: 294860c47cd3678c46422ce57da366724e1dc629

1 files changed, 39 insertions, 40 deletions

diff --git a/disassembler_win32.cc b/disassembler_win32.cc
index a23201b..37e43e5 100644
--- a/disassembler_win32.cc
+++ b/disassembler_win32.cc
@@ -24,7 +24,6 @@ namespace {
 // Decides whether |image| points to a Win32 PE file. If this is a possibility,
 // assigns |source| to enable further parsing, and returns true. Otherwise
 // leaves |source| at an undefined state and returns false.
-template <class Traits>
 bool ReadWin32Header(ConstBufferView image, BufferSource* source) {
   *source = BufferSource(image);
 
@@ -47,9 +46,9 @@ bool ReadWin32Header(ConstBufferView image, BufferSource* source) {
   return true;
 }
 
-template <class Traits>
+template <class TRAITS>
 const pe::ImageDataDirectory* ReadDataDirectory(
-    const typename Traits::ImageOptionalHeader* optional_header,
+    const typename TRAITS::ImageOptionalHeader* optional_header,
     size_t index) {
   if (index >= optional_header->number_of_rva_and_sizes)
     return nullptr;
@@ -57,7 +56,7 @@ const pe::ImageDataDirectory* ReadDataDirectory(
 }
 
 // Decides whether |section| (assumed value) is a section that contains code.
-template <class Traits>
+template <class TRAITS>
 bool IsWin32CodeSection(const pe::ImageSectionHeader& section) {
   return (section.characteristics & kCodeCharacteristics) ==
          kCodeCharacteristics;
@@ -82,31 +81,31 @@ const char Win32X64Traits::kExeTypeString[] = "Windows PE x64";
 /******** DisassemblerWin32 ********/
 
 // static.
-template <class Traits>
-bool DisassemblerWin32<Traits>::QuickDetect(ConstBufferView image) {
+template <class TRAITS>
+bool DisassemblerWin32<TRAITS>::QuickDetect(ConstBufferView image) {
   BufferSource source;
-  return ReadWin32Header<Traits>(image, &source);
+  return ReadWin32Header(image, &source);
 }
 
 // |num_equivalence_iterations_| = 2 for reloc -> abs32.
-template <class Traits>
-DisassemblerWin32<Traits>::DisassemblerWin32() : Disassembler(2) {}
+template <class TRAITS>
+DisassemblerWin32<TRAITS>::DisassemblerWin32() : Disassembler(2) {}
 
-template <class Traits>
-DisassemblerWin32<Traits>::~DisassemblerWin32() = default;
+template <class TRAITS>
+DisassemblerWin32<TRAITS>::~DisassemblerWin32() = default;
 
-template <class Traits>
-ExecutableType DisassemblerWin32<Traits>::GetExeType() const {
+template <class TRAITS>
+ExecutableType DisassemblerWin32<TRAITS>::GetExeType() const {
   return Traits::kExeType;
 }
 
-template <class Traits>
-std::string DisassemblerWin32<Traits>::GetExeTypeString() const {
+template <class TRAITS>
+std::string DisassemblerWin32<TRAITS>::GetExeTypeString() const {
   return Traits::kExeTypeString;
 }
 
-template <class Traits>
-std::vector<ReferenceGroup> DisassemblerWin32<Traits>::MakeReferenceGroups()
+template <class TRAITS>
+std::vector<ReferenceGroup> DisassemblerWin32<TRAITS>::MakeReferenceGroups()
     const {
   return {
       {ReferenceTypeTraits{2, TypeTag(kReloc), PoolTag(kReloc)},
@@ -118,8 +117,8 @@ std::vector<ReferenceGroup> DisassemblerWin32<Traits>::MakeReferenceGroups()
   };
 }
 
-template <class Traits>
-std::unique_ptr<ReferenceReader> DisassemblerWin32<Traits>::MakeReadRelocs(
+template <class TRAITS>
+std::unique_ptr<ReferenceReader> DisassemblerWin32<TRAITS>::MakeReadRelocs(
     offset_t lo,
     offset_t hi) {
   if (!ParseAndStoreRelocBlocks())
@@ -135,8 +134,8 @@ std::unique_ptr<ReferenceReader> DisassemblerWin32<Traits>::MakeReadRelocs(
                                             translator_);
 }
 
-template <class Traits>
-std::unique_ptr<ReferenceReader> DisassemblerWin32<Traits>::MakeReadAbs32(
+template <class TRAITS>
+std::unique_ptr<ReferenceReader> DisassemblerWin32<TRAITS>::MakeReadAbs32(
     offset_t lo,
     offset_t hi) {
   ParseAndStoreAbs32();
@@ -146,8 +145,8 @@ std::unique_ptr<ReferenceReader> DisassemblerWin32<Traits>::MakeReadAbs32(
                                             translator_);
 }
 
-template <class Traits>
-std::unique_ptr<ReferenceReader> DisassemblerWin32<Traits>::MakeReadRel32(
+template <class TRAITS>
+std::unique_ptr<ReferenceReader> DisassemblerWin32<TRAITS>::MakeReadRel32(
     offset_t lo,
     offset_t hi) {
   ParseAndStoreRel32();
@@ -155,8 +154,8 @@ std::unique_ptr<ReferenceReader> DisassemblerWin32<Traits>::MakeReadRel32(
                                           translator_);
 }
 
-template <class Traits>
-std::unique_ptr<ReferenceWriter> DisassemblerWin32<Traits>::MakeWriteRelocs(
+template <class TRAITS>
+std::unique_ptr<ReferenceWriter> DisassemblerWin32<TRAITS>::MakeWriteRelocs(
     MutableBufferView image) {
   if (!ParseAndStoreRelocBlocks())
     return std::make_unique<EmptyReferenceWriter>();
@@ -166,30 +165,30 @@ std::unique_ptr<ReferenceWriter> DisassemblerWin32<Traits>::MakeWriteRelocs(
                                             translator_);
 }
 
-template <class Traits>
-std::unique_ptr<ReferenceWriter> DisassemblerWin32<Traits>::MakeWriteAbs32(
+template <class TRAITS>
+std::unique_ptr<ReferenceWriter> DisassemblerWin32<TRAITS>::MakeWriteAbs32(
     MutableBufferView image) {
   return std::make_unique<Abs32WriterWin32>(
       image, AbsoluteAddress(Traits::kBitness, image_base_), translator_);
 }
 
-template <class Traits>
-std::unique_ptr<ReferenceWriter> DisassemblerWin32<Traits>::MakeWriteRel32(
+template <class TRAITS>
+std::unique_ptr<ReferenceWriter> DisassemblerWin32<TRAITS>::MakeWriteRel32(
     MutableBufferView image) {
   return std::make_unique<Rel32WriterX86>(image, translator_);
 }
 
-template <class Traits>
-bool DisassemblerWin32<Traits>::Parse(ConstBufferView image) {
+template <class TRAITS>
+bool DisassemblerWin32<TRAITS>::Parse(ConstBufferView image) {
   image_ = image;
   return ParseHeader();
 }
 
-template <class Traits>
-bool DisassemblerWin32<Traits>::ParseHeader() {
+template <class TRAITS>
+bool DisassemblerWin32<TRAITS>::ParseHeader() {
   BufferSource source;
 
-  if (!ReadWin32Header<Traits>(image_, &source))
+  if (!ReadWin32Header(image_, &source))
     return false;
 
   constexpr size_t kDataDirBase =
@@ -297,8 +296,8 @@ bool DisassemblerWin32<Traits>::ParseHeader() {
   return true;
 }
 
-template <class Traits>
-bool DisassemblerWin32<Traits>::ParseAndStoreRelocBlocks() {
+template <class TRAITS>
+bool DisassemblerWin32<TRAITS>::ParseAndStoreRelocBlocks() {
   if (has_parsed_relocs_)
     return reloc_region_.lo() != kInvalidOffset;
 
@@ -324,8 +323,8 @@ bool DisassemblerWin32<Traits>::ParseAndStoreRelocBlocks() {
   return true;
 }
 
-template <class Traits>
-bool DisassemblerWin32<Traits>::ParseAndStoreAbs32() {
+template <class TRAITS>
+bool DisassemblerWin32<TRAITS>::ParseAndStoreAbs32() {
   if (has_parsed_abs32_)
     return true;
   has_parsed_abs32_ = true;
@@ -355,8 +354,8 @@ bool DisassemblerWin32<Traits>::ParseAndStoreAbs32() {
   return true;
 }
 
-template <class Traits>
-bool DisassemblerWin32<Traits>::ParseAndStoreRel32() {
+template <class TRAITS>
+bool DisassemblerWin32<TRAITS>::ParseAndStoreRel32() {
   if (has_parsed_rel32_)
     return true;
   has_parsed_rel32_ = true;