[WebAssembly] Add llvm-objdump support for wasm file format

This is the first part of an effort to add wasm binary
support across all llvm tools.

Patch by Sam Clegg

Differential Revision: https://reviews.llvm.org/D26172

llvm-svn: 288251

5 files changed, 322 insertions, 1 deletions

diff --git a/llvm/lib/Object/Binary.cpp b/llvm/lib/Object/Binary.cpp
index 2d2192d2a14..8467d349cd9 100644
--- a/llvm/lib/Object/Binary.cpp
+++ b/llvm/lib/Object/Binary.cpp
@@ -63,6 +63,7 @@ Expected<std::unique_ptr<Binary>> object::createBinary(MemoryBufferRef Buffer,
     case sys::fs::file_magic::coff_import_library:
     case sys::fs::file_magic::pecoff_executable:
     case sys::fs::file_magic::bitcode:
+    case sys::fs::file_magic::wasm_object:
       return ObjectFile::createSymbolicFile(Buffer, Type, Context);
     case sys::fs::file_magic::macho_universal_binary:
       return MachOUniversalBinary::create(Buffer);
diff --git a/llvm/lib/Object/CMakeLists.txt b/llvm/lib/Object/CMakeLists.txt
index 0a37cc360fe..4ac92bcd63e 100644
--- a/llvm/lib/Object/CMakeLists.txt
+++ b/llvm/lib/Object/CMakeLists.txt
@@ -15,6 +15,7 @@ add_llvm_library(LLVMObject
   RecordStreamer.cpp
   SymbolicFile.cpp
   SymbolSize.cpp
+  WasmObjectFile.cpp
 
   ADDITIONAL_HEADER_DIRS
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/Object
diff --git a/llvm/lib/Object/ObjectFile.cpp b/llvm/lib/Object/ObjectFile.cpp
index 996463d6728..f36388b677f 100644
--- a/llvm/lib/Object/ObjectFile.cpp
+++ b/llvm/lib/Object/ObjectFile.cpp
@@ -11,9 +11,10 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Object/ObjectFile.h"
 #include "llvm/Object/COFF.h"
 #include "llvm/Object/MachO.h"
-#include "llvm/Object/ObjectFile.h"
+#include "llvm/Object/Wasm.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -105,6 +106,8 @@ ObjectFile::createObjectFile(MemoryBufferRef Object, sys::fs::file_magic Type) {
   case sys::fs::file_magic::coff_import_library:
   case sys::fs::file_magic::pecoff_executable:
     return errorOrToExpected(createCOFFObjectFile(Object));
+  case sys::fs::file_magic::wasm_object:
+    return createWasmObjectFile(Object);
   }
   llvm_unreachable("Unexpected Object File Type");
 }
diff --git a/llvm/lib/Object/SymbolicFile.cpp b/llvm/lib/Object/SymbolicFile.cpp
index b6a8b06f08e..4b51a49cf34 100644
--- a/llvm/lib/Object/SymbolicFile.cpp
+++ b/llvm/lib/Object/SymbolicFile.cpp
@@ -58,6 +58,7 @@ Expected<std::unique_ptr<SymbolicFile>> SymbolicFile::createSymbolicFile(
   case sys::fs::file_magic::macho_dsym_companion:
   case sys::fs::file_magic::macho_kext_bundle:
   case sys::fs::file_magic::pecoff_executable:
+  case sys::fs::file_magic::wasm_object:
     return ObjectFile::createObjectFile(Object, Type);
   case sys::fs::file_magic::coff_import_library:
     return std::unique_ptr<SymbolicFile>(new COFFImportFile(Object));
diff --git a/llvm/lib/Object/WasmObjectFile.cpp b/llvm/lib/Object/WasmObjectFile.cpp
new file mode 100644
index 00000000000..43f436374b1
--- /dev/null
+++ b/llvm/lib/Object/WasmObjectFile.cpp
@@ -0,0 +1,315 @@
+//===- WasmObjectFile.cpp - Wasm object file implementation -----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Object/Wasm.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/LEB128.h"
+
+#include <iostream>
+
+namespace llvm {
+namespace object {
+
+Expected<std::unique_ptr<WasmObjectFile>>
+ObjectFile::createWasmObjectFile(MemoryBufferRef Buffer) {
+  Error Err = Error::success();
+  auto ObjectFile = llvm::make_unique<WasmObjectFile>(Buffer, Err);
+  if (Err)
+    return std::move(Err);
+
+  return std::move(ObjectFile);
+}
+
+namespace {
+
+uint32_t readUint32(const uint8_t *&Ptr) {
+  uint32_t Result = support::endian::read32le(Ptr);
+  Ptr += sizeof(Result);
+  return Result;
+}
+
+uint64_t readULEB128(const uint8_t *&Ptr) {
+  unsigned Count;
+  uint64_t Result = decodeULEB128(Ptr, &Count);
+  Ptr += Count;
+  return Result;
+}
+
+StringRef readString(const uint8_t *&Ptr) {
+  uint32_t StringLen = readULEB128(Ptr);
+  StringRef Return = StringRef(reinterpret_cast<const char *>(Ptr), StringLen);
+  Ptr += StringLen;
+  return Return;
+}
+
+Error readSection(wasm::WasmSection &Section, const uint8_t *&Ptr,
+                  const uint8_t *Start) {
+  // TODO(sbc): Avoid reading past EOF in the case of malformed files.
+  Section.Offset = Ptr - Start;
+  Section.Type = readULEB128(Ptr);
+  uint32_t Size = readULEB128(Ptr);
+  if (Size == 0)
+    return make_error<StringError>("Zero length section",
+                                   object_error::parse_failed);
+  Section.Content = ArrayRef<uint8_t>(Ptr, Size);
+  Ptr += Size;
+  return Error::success();
+}
+}
+
+WasmObjectFile::WasmObjectFile(MemoryBufferRef Buffer, Error &Err)
+    : ObjectFile(Binary::ID_Wasm, Buffer) {
+  ErrorAsOutParameter ErrAsOutParam(&Err);
+  Header.Magic = getData().substr(0, 4);
+  if (Header.Magic != StringRef("\0asm", 4)) {
+    Err = make_error<StringError>("Bad magic number",
+                                  object_error::parse_failed);
+    return;
+  }
+  const uint8_t *Ptr = getPtr(4);
+  Header.Version = readUint32(Ptr);
+  if (Header.Version != wasm::WasmVersion) {
+    Err = make_error<StringError>("Bad version number",
+                                  object_error::parse_failed);
+    return;
+  }
+
+  const uint8_t *Eof = getPtr(getData().size());
+  wasm::WasmSection Sec;
+  while (Ptr < Eof) {
+    if ((Err = readSection(Sec, Ptr, getPtr(0))))
+      return;
+    if (Sec.Type == wasm::WASM_SEC_USER) {
+      if ((Err = parseUserSection(Sec, Sec.Content.data(), Sec.Content.size())))
+        return;
+    }
+    Sections.push_back(Sec);
+  }
+}
+
+Error WasmObjectFile::parseUserSection(wasm::WasmSection &Sec,
+                                       const uint8_t *Ptr, size_t Length) {
+  Sec.Name = readString(Ptr);
+  return Error::success();
+}
+
+const uint8_t *WasmObjectFile::getPtr(size_t Offset) const {
+  return reinterpret_cast<const uint8_t *>(getData().substr(Offset, 1).data());
+}
+
+const wasm::WasmObjectHeader &WasmObjectFile::getHeader() const {
+  return Header;
+}
+
+void WasmObjectFile::moveSymbolNext(DataRefImpl &Symb) const {
+  llvm_unreachable("not yet implemented");
+}
+
+std::error_code WasmObjectFile::printSymbolName(raw_ostream &OS,
+                                                DataRefImpl Symb) const {
+  llvm_unreachable("not yet implemented");
+  return object_error::invalid_symbol_index;
+}
+
+uint32_t WasmObjectFile::getSymbolFlags(DataRefImpl Symb) const {
+  llvm_unreachable("not yet implemented");
+  return 0;
+}
+
+basic_symbol_iterator WasmObjectFile::symbol_begin() const {
+  return BasicSymbolRef(DataRefImpl(), this);
+}
+
+basic_symbol_iterator WasmObjectFile::symbol_end() const {
+  return BasicSymbolRef(DataRefImpl(), this);
+}
+
+Expected<StringRef> WasmObjectFile::getSymbolName(DataRefImpl Symb) const {
+  llvm_unreachable("not yet implemented");
+  return errorCodeToError(object_error::invalid_symbol_index);
+}
+
+Expected<uint64_t> WasmObjectFile::getSymbolAddress(DataRefImpl Symb) const {
+  llvm_unreachable("not yet implemented");
+  return errorCodeToError(object_error::invalid_symbol_index);
+}
+
+uint64_t WasmObjectFile::getSymbolValueImpl(DataRefImpl Symb) const {
+  llvm_unreachable("not yet implemented");
+  return 0;
+}
+
+uint32_t WasmObjectFile::getSymbolAlignment(DataRefImpl Symb) const {
+  llvm_unreachable("not yet implemented");
+  return 0;
+}
+
+uint64_t WasmObjectFile::getCommonSymbolSizeImpl(DataRefImpl Symb) const {
+  llvm_unreachable("not yet implemented");
+  return 0;
+}
+
+Expected<SymbolRef::Type>
+WasmObjectFile::getSymbolType(DataRefImpl Symb) const {
+  llvm_unreachable("not yet implemented");
+  return errorCodeToError(object_error::invalid_symbol_index);
+}
+
+Expected<section_iterator>
+WasmObjectFile::getSymbolSection(DataRefImpl Symb) const {
+  llvm_unreachable("not yet implemented");
+  return errorCodeToError(object_error::invalid_symbol_index);
+}
+
+void WasmObjectFile::moveSectionNext(DataRefImpl &Sec) const { Sec.d.a++; }
+
+std::error_code WasmObjectFile::getSectionName(DataRefImpl Sec,
+                                               StringRef &Res) const {
+  const wasm::WasmSection &S = Sections[Sec.d.a];
+#define ECase(X)                                                               \
+  case wasm::WASM_SEC_##X:                                                     \
+    Res = #X;                                                                  \
+    break
+  switch (S.Type) {
+    ECase(TYPE);
+    ECase(IMPORT);
+    ECase(FUNCTION);
+    ECase(TABLE);
+    ECase(MEMORY);
+    ECase(GLOBAL);
+    ECase(EXPORT);
+    ECase(START);
+    ECase(ELEM);
+    ECase(CODE);
+    ECase(DATA);
+  case wasm::WASM_SEC_USER:
+    Res = S.Name;
+    break;
+  default:
+    return object_error::invalid_section_index;
+  }
+#undef ECase
+  return std::error_code();
+}
+
+uint64_t WasmObjectFile::getSectionAddress(DataRefImpl Sec) const { return 0; }
+
+uint64_t WasmObjectFile::getSectionSize(DataRefImpl Sec) const {
+  const wasm::WasmSection &S = Sections[Sec.d.a];
+  return S.Content.size();
+}
+
+std::error_code WasmObjectFile::getSectionContents(DataRefImpl Sec,
+                                                   StringRef &Res) const {
+  const wasm::WasmSection &S = Sections[Sec.d.a];
+  // This will never fail since wasm sections can never be empty (user-sections
+  // must have a name and non-user sections each have a defined structure).
+  Res = StringRef(reinterpret_cast<const char *>(S.Content.data()),
+                  S.Content.size());
+  return std::error_code();
+}
+
+uint64_t WasmObjectFile::getSectionAlignment(DataRefImpl Sec) const {
+  return 1;
+}
+
+bool WasmObjectFile::isSectionCompressed(DataRefImpl Sec) const {
+  return false;
+}
+
+bool WasmObjectFile::isSectionText(DataRefImpl Sec) const {
+  const wasm::WasmSection &S = Sections[Sec.d.a];
+  return S.Type == wasm::WASM_SEC_CODE;
+}
+
+bool WasmObjectFile::isSectionData(DataRefImpl Sec) const {
+  const wasm::WasmSection &S = Sections[Sec.d.a];
+  return S.Type == wasm::WASM_SEC_DATA;
+}
+
+bool WasmObjectFile::isSectionBSS(DataRefImpl Sec) const { return false; }
+
+bool WasmObjectFile::isSectionVirtual(DataRefImpl Sec) const { return false; }
+
+bool WasmObjectFile::isSectionBitcode(DataRefImpl Sec) const { return false; }
+
+relocation_iterator WasmObjectFile::section_rel_begin(DataRefImpl Sec) const {
+  llvm_unreachable("not yet implemented");
+  RelocationRef Rel;
+  return relocation_iterator(Rel);
+}
+
+relocation_iterator WasmObjectFile::section_rel_end(DataRefImpl Sec) const {
+  llvm_unreachable("not yet implemented");
+  RelocationRef Rel;
+  return relocation_iterator(Rel);
+}
+
+section_iterator WasmObjectFile::getRelocatedSection(DataRefImpl Sec) const {
+  llvm_unreachable("not yet implemented");
+  SectionRef Ref;
+  return section_iterator(Ref);
+}
+
+void WasmObjectFile::moveRelocationNext(DataRefImpl &Rel) const {
+  llvm_unreachable("not yet implemented");
+}
+
+uint64_t WasmObjectFile::getRelocationOffset(DataRefImpl Rel) const {
+  llvm_unreachable("not yet implemented");
+  return 0;
+}
+
+symbol_iterator WasmObjectFile::getRelocationSymbol(DataRefImpl Rel) const {
+  llvm_unreachable("not yet implemented");
+  SymbolRef Ref;
+  return symbol_iterator(Ref);
+}
+
+uint64_t WasmObjectFile::getRelocationType(DataRefImpl Rel) const {
+  llvm_unreachable("not yet implemented");
+  return 0;
+}
+
+void WasmObjectFile::getRelocationTypeName(
+    DataRefImpl Rel, SmallVectorImpl<char> &Result) const {
+  llvm_unreachable("not yet implemented");
+}
+
+section_iterator WasmObjectFile::section_begin() const {
+  DataRefImpl Ref;
+  Ref.d.a = 0;
+  return section_iterator(SectionRef(Ref, this));
+}
+
+section_iterator WasmObjectFile::section_end() const {
+  DataRefImpl Ref;
+  Ref.d.a = Sections.size();
+  return section_iterator(SectionRef(Ref, this));
+}
+
+uint8_t WasmObjectFile::getBytesInAddress() const { return 4; }
+
+StringRef WasmObjectFile::getFileFormatName() const { return "WASM"; }
+
+unsigned WasmObjectFile::getArch() const { return Triple::wasm32; }
+
+SubtargetFeatures WasmObjectFile::getFeatures() const {
+  return SubtargetFeatures();
+}
+
+bool WasmObjectFile::isRelocatableObject() const { return false; }
+
+const wasm::WasmSection *
+WasmObjectFile::getWasmSection(const SectionRef &Section) const {
+  return &Sections[Section.getRawDataRefImpl().d.a];
+}
+
+} // end namespace object
+} // end namespace llvm