Imported Upstream version 6.10.0.49

Former-commit-id: 1d6753294b2993e1fbf92de9366bb9544db4189b

external/llvm-project/lld/.arcconfig

@@ -0,0 +1,4 @@
+{
+  "repository.callsign" : "LLD",
+  "conduit_uri" : "https://reviews.llvm.org/"
+}

external/llvm-project/lld/.clang-format

@@ -0,0 +1 @@
+BasedOnStyle: LLVM

external/llvm-project/lld/.gitignore

@@ -0,0 +1,24 @@
+#==============================================================================#
+# This file specifies intentionally untracked files that git should ignore.
+# See: http://www.kernel.org/pub/software/scm/git/docs/gitignore.html
+#==============================================================================#
+
+#==============================================================================#
+# File extensions to be ignored anywhere in the tree.
+#==============================================================================#
+# Temp files created by most text editors.
+*~
+# Merge files created by git.
+*.orig
+# Byte compiled python modules.
+*.pyc
+# vim swap files
+.*.swp
+# Mac OS X Finder layout info
+.DS_Store
+
+#==============================================================================#
+# Directories to be ignored.
+#==============================================================================#
+# Sphinx build files.
+docs/_build

external/llvm-project/lld/CMakeLists.txt

@@ -0,0 +1,226 @@
+# Check if lld is built as a standalone project.
+if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+  project(lld)
+  cmake_minimum_required(VERSION 3.4.3)
+
+  set(CMAKE_INCLUDE_CURRENT_DIR ON)
+  set(LLD_BUILT_STANDALONE TRUE)
+
+  find_program(LLVM_CONFIG_PATH "llvm-config" DOC "Path to llvm-config binary")
+  if(NOT LLVM_CONFIG_PATH)
+    message(FATAL_ERROR "llvm-config not found: specify LLVM_CONFIG_PATH")
+  endif()
+
+  execute_process(COMMAND "${LLVM_CONFIG_PATH}"
+                          "--obj-root"
+                          "--includedir"
+                          "--cmakedir"
+                          "--src-root"
+                  RESULT_VARIABLE HAD_ERROR
+                  OUTPUT_VARIABLE LLVM_CONFIG_OUTPUT
+                  OUTPUT_STRIP_TRAILING_WHITESPACE)
+  if(HAD_ERROR)
+    message(FATAL_ERROR "llvm-config failed with status ${HAD_ERROR}")
+  endif()
+
+  string(REGEX REPLACE "[ \t]*[\r\n]+[ \t]*" ";" LLVM_CONFIG_OUTPUT "${LLVM_CONFIG_OUTPUT}")
+
+  list(GET LLVM_CONFIG_OUTPUT 0 OBJ_ROOT)
+  list(GET LLVM_CONFIG_OUTPUT 1 MAIN_INCLUDE_DIR)
+  list(GET LLVM_CONFIG_OUTPUT 2 LLVM_CMAKE_PATH)
+  list(GET LLVM_CONFIG_OUTPUT 3 MAIN_SRC_DIR)
+
+  set(LLVM_OBJ_ROOT ${OBJ_ROOT} CACHE PATH "path to LLVM build tree")
+  set(LLVM_MAIN_INCLUDE_DIR ${MAIN_INCLUDE_DIR} CACHE PATH "path to llvm/include")
+  set(LLVM_MAIN_SRC_DIR ${MAIN_SRC_DIR} CACHE PATH "Path to LLVM source tree")
+
+  file(TO_CMAKE_PATH ${LLVM_OBJ_ROOT} LLVM_BINARY_DIR)
+
+  if(NOT EXISTS "${LLVM_CMAKE_PATH}/LLVMConfig.cmake")
+    message(FATAL_ERROR "LLVMConfig.cmake not found")
+  endif()
+  include("${LLVM_CMAKE_PATH}/LLVMConfig.cmake")
+
+  list(APPEND CMAKE_MODULE_PATH "${LLVM_CMAKE_PATH}")
+
+  set(PACKAGE_VERSION "${LLVM_PACKAGE_VERSION}")
+  include_directories("${LLVM_BINARY_DIR}/include" ${LLVM_INCLUDE_DIRS})
+  link_directories(${LLVM_LIBRARY_DIRS})
+
+  set(LLVM_LIBRARY_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib${LLVM_LIBDIR_SUFFIX})
+  set(LLVM_RUNTIME_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin)
+  find_program(LLVM_TABLEGEN_EXE "llvm-tblgen" ${LLVM_TOOLS_BINARY_DIR} NO_DEFAULT_PATH)
+
+  include(AddLLVM)
+  include(TableGen)
+  include(HandleLLVMOptions)
+
+  if(LLVM_INCLUDE_TESTS)
+    set(Python_ADDITIONAL_VERSIONS 2.7)
+    include(FindPythonInterp)
+    if(NOT PYTHONINTERP_FOUND)
+      message(FATAL_ERROR
+"Unable to find Python interpreter, required for testing.
+
+Please install Python or specify the PYTHON_EXECUTABLE CMake variable.")
+    endif()
+
+    if(${PYTHON_VERSION_STRING} VERSION_LESS 2.7)
+      message(FATAL_ERROR "Python 2.7 or newer is required")
+    endif()
+
+    # Check prebuilt llvm/utils.
+    if(EXISTS ${LLVM_TOOLS_BINARY_DIR}/FileCheck${CMAKE_EXECUTABLE_SUFFIX}
+        AND EXISTS ${LLVM_TOOLS_BINARY_DIR}/not${CMAKE_EXECUTABLE_SUFFIX})
+      set(LLVM_UTILS_PROVIDED ON)
+    endif()
+
+    if(EXISTS ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
+      # Note: path not really used, except for checking if lit was found
+      set(LLVM_LIT ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
+      if(NOT LLVM_UTILS_PROVIDED)
+        add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/FileCheck utils/FileCheck)
+        add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/not utils/not)
+        set(LLVM_UTILS_PROVIDED ON)
+        set(LLD_TEST_DEPS FileCheck not)
+      endif()
+      set(UNITTEST_DIR ${LLVM_MAIN_SRC_DIR}/utils/unittest)
+      if(EXISTS ${UNITTEST_DIR}/googletest/include/gtest/gtest.h
+          AND NOT EXISTS ${LLVM_LIBRARY_DIR}/${CMAKE_STATIC_LIBRARY_PREFIX}gtest${CMAKE_STATIC_LIBRARY_SUFFIX}
+          AND EXISTS ${UNITTEST_DIR}/CMakeLists.txt)
+        add_subdirectory(${UNITTEST_DIR} utils/unittest)
+      endif()
+    else()
+      # Seek installed Lit.
+      find_program(LLVM_LIT
+                   NAMES llvm-lit lit.py lit
+                   PATHS "${LLVM_MAIN_SRC_DIR}/utils/lit"
+                   DOC "Path to lit.py")
+    endif()
+
+    if(LLVM_LIT)
+      # Define the default arguments to use with 'lit', and an option for the user
+      # to override.
+      set(LIT_ARGS_DEFAULT "-sv")
+      if (MSVC OR XCODE)
+        set(LIT_ARGS_DEFAULT "${LIT_ARGS_DEFAULT} --no-progress-bar")
+      endif()
+      set(LLVM_LIT_ARGS "${LIT_ARGS_DEFAULT}" CACHE STRING "Default options for lit")
+
+      # On Win32 hosts, provide an option to specify the path to the GnuWin32 tools.
+      if(WIN32 AND NOT CYGWIN)
+        set(LLVM_LIT_TOOLS_DIR "" CACHE PATH "Path to GnuWin32 tools")
+      endif()
+    else()
+      set(LLVM_INCLUDE_TESTS OFF)
+    endif()
+  endif()
+endif()
+
+set(LLD_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
+set(LLD_INCLUDE_DIR ${LLD_SOURCE_DIR}/include )
+set(LLD_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
+
+# Compute the LLD version from the LLVM version.
+string(REGEX MATCH "[0-9]+\\.[0-9]+(\\.[0-9]+)?" LLD_VERSION
+  ${PACKAGE_VERSION})
+message(STATUS "LLD version: ${LLD_VERSION}")
+
+string(REGEX REPLACE "([0-9]+)\\.[0-9]+(\\.[0-9]+)?" "\\1" LLD_VERSION_MAJOR
+  ${LLD_VERSION})
+string(REGEX REPLACE "[0-9]+\\.([0-9]+)(\\.[0-9]+)?" "\\1" LLD_VERSION_MINOR
+  ${LLD_VERSION})
+
+# Determine LLD revision and repository.
+# TODO: Figure out a way to get the revision and the repository on windows.
+if ( NOT CMAKE_SYSTEM_NAME MATCHES "Windows" )
+  execute_process(COMMAND ${CMAKE_SOURCE_DIR}/utils/GetSourceVersion ${LLD_SOURCE_DIR}
+                  OUTPUT_VARIABLE LLD_REVISION)
+
+  execute_process(COMMAND ${CMAKE_SOURCE_DIR}/utils/GetRepositoryPath ${LLD_SOURCE_DIR}
+                  OUTPUT_VARIABLE LLD_REPOSITORY)
+  if ( LLD_REPOSITORY )
+    # Replace newline characters with spaces
+    string(REGEX REPLACE "(\r?\n)+" " " LLD_REPOSITORY ${LLD_REPOSITORY})
+    # Remove leading spaces
+    STRING(REGEX REPLACE "^[ \t\r\n]+" "" LLD_REPOSITORY "${LLD_REPOSITORY}" )
+    # Remove trailing spaces
+    string(REGEX REPLACE "(\ )+$" "" LLD_REPOSITORY ${LLD_REPOSITORY})
+  endif()
+
+  if ( LLD_REVISION )
+    # Replace newline characters with spaces
+    string(REGEX REPLACE "(\r?\n)+" " " LLD_REVISION ${LLD_REVISION})
+    # Remove leading spaces
+    STRING(REGEX REPLACE "^[ \t\r\n]+" "" LLD_REVISION "${LLD_REVISION}" )
+    # Remove trailing spaces
+    string(REGEX REPLACE "(\ )+$" "" LLD_REVISION ${LLD_REVISION})
+  endif()
+endif ()
+
+# Configure the Version.inc file.
+configure_file(
+  ${CMAKE_CURRENT_SOURCE_DIR}/include/lld/Common/Version.inc.in
+  ${CMAKE_CURRENT_BINARY_DIR}/include/lld/Common/Version.inc)
+
+
+if (CMAKE_SOURCE_DIR STREQUAL CMAKE_BINARY_DIR)
+  message(FATAL_ERROR "In-source builds are not allowed. CMake would overwrite "
+"the makefiles distributed with LLVM. Please create a directory and run cmake "
+"from there, passing the path to this source directory as the last argument. "
+"This process created the file `CMakeCache.txt' and the directory "
+"`CMakeFiles'. Please delete them.")
+endif()
+
+list (APPEND CMAKE_MODULE_PATH "${LLD_SOURCE_DIR}/cmake/modules")
+
+include(AddLLD)
+
+option(LLD_USE_VTUNE
+       "Enable VTune user task tracking."
+       OFF)
+if (LLD_USE_VTUNE)
+  find_package(VTune)
+  if (VTUNE_FOUND)
+    include_directories(${VTune_INCLUDE_DIRS})
+    list(APPEND LLVM_COMMON_LIBS ${VTune_LIBRARIES})
+    add_definitions(-DLLD_HAS_VTUNE)
+  endif()
+endif()
+
+option(LLD_BUILD_TOOLS
+  "Build the lld tools. If OFF, just generate build targets." ON)
+
+if (MSVC)
+  add_definitions(-wd4530) # Suppress 'warning C4530: C++ exception handler used, but unwind semantics are not enabled.'
+  add_definitions(-wd4062) # Suppress 'warning C4062: enumerator X in switch of enum Y is not handled' from system header.
+endif()
+
+include_directories(BEFORE
+  ${CMAKE_CURRENT_BINARY_DIR}/include
+  ${CMAKE_CURRENT_SOURCE_DIR}/include
+  )
+
+if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
+  install(DIRECTORY include/
+    DESTINATION include
+    FILES_MATCHING
+    PATTERN "*.h"
+    PATTERN ".svn" EXCLUDE
+    )
+endif()
+
+add_subdirectory(Common)
+add_subdirectory(lib)
+add_subdirectory(tools/lld)
+
+if (LLVM_INCLUDE_TESTS)
+  add_subdirectory(test)
+  add_subdirectory(unittests)
+endif()
+
+add_subdirectory(docs)
+add_subdirectory(COFF)
+add_subdirectory(ELF)
+add_subdirectory(MinGW)
+add_subdirectory(wasm)

external/llvm-project/lld/CODE_OWNERS.TXT

@@ -0,0 +1,22 @@
+This file is a list of the people responsible for ensuring that patches for a
+particular part of LLD are reviewed, either by themself or by someone else.
+They are also the gatekeepers for their part of LLD, with the final word on
+what goes in or not.
+
+The list is sorted by surname and formatted to allow easy grepping and
+beautification by scripts.  The fields are: name (N), email (E), web-address
+(W), PGP key ID and fingerprint (P), description (D), and snail-mail address
+(S). Each entry should contain at least the (N), (E) and (D) fields.
+
+
+N: Rui Ueyama
+E: ruiu@google.com
+D: COFF, ELF backends (COFF/* ELF/*)
+
+N: Lang Hames, Nick Kledzik
+E: lhames@gmail.com, kledzik@apple.com
+D: Mach-O backend
+
+N: Sam Clegg
+E: sbc@chromium.org
+D: WebAssembly backend (wasm/*)

external/llvm-project/lld/COFF/CMakeLists.txt

@@ -0,0 +1,48 @@
+set(LLVM_TARGET_DEFINITIONS Options.td)
+tablegen(LLVM Options.inc -gen-opt-parser-defs)
+add_public_tablegen_target(COFFOptionsTableGen)
+
+if(NOT LLD_BUILT_STANDALONE)
+  set(tablegen_deps intrinsics_gen)
+endif()
+
+add_lld_library(lldCOFF
+  Chunks.cpp
+  DLL.cpp
+  Driver.cpp
+  DriverUtils.cpp
+  ICF.cpp
+  InputFiles.cpp
+  LTO.cpp
+  MapFile.cpp
+  MarkLive.cpp
+  MinGW.cpp
+  PDB.cpp
+  Strings.cpp
+  SymbolTable.cpp
+  Symbols.cpp
+  Writer.cpp
+
+  LINK_COMPONENTS
+  ${LLVM_TARGETS_TO_BUILD}
+  BinaryFormat
+  Core
+  DebugInfoCodeView
+  DebugInfoMSF
+  DebugInfoPDB
+  LibDriver
+  LTO
+  MC
+  Object
+  Option
+  Support
+  WindowsManifest
+
+  LINK_LIBS
+  lldCommon
+  ${LLVM_PTHREAD_LIB}
+
+  DEPENDS
+  COFFOptionsTableGen
+  ${tablegen_deps}
+  )

external/llvm-project/lld/COFF/Chunks.h

@@ -0,0 +1,365 @@
+//===- Chunks.h -------------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_COFF_CHUNKS_H
+#define LLD_COFF_CHUNKS_H
+
+#include "Config.h"
+#include "InputFiles.h"
+#include "lld/Common/LLVM.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/iterator.h"
+#include "llvm/ADT/iterator_range.h"
+#include "llvm/Object/COFF.h"
+#include <utility>
+#include <vector>
+
+namespace lld {
+namespace coff {
+
+using llvm::COFF::ImportDirectoryTableEntry;
+using llvm::object::COFFSymbolRef;
+using llvm::object::SectionRef;
+using llvm::object::coff_relocation;
+using llvm::object::coff_section;
+
+class Baserel;
+class Defined;
+class DefinedImportData;
+class DefinedRegular;
+class ObjFile;
+class OutputSection;
+class Symbol;
+
+// Mask for section types (code, data, bss, disacardable, etc.)
+// and permissions (writable, readable or executable).
+const uint32_t PermMask = 0xFF0000F0;
+
+// A Chunk represents a chunk of data that will occupy space in the
+// output (if the resolver chose that). It may or may not be backed by
+// a section of an input file. It could be linker-created data, or
+// doesn't even have actual data (if common or bss).
+class Chunk {
+public:
+  enum Kind { SectionKind, OtherKind };
+  Kind kind() const { return ChunkKind; }
+  virtual ~Chunk() = default;
+
+  // Returns the size of this chunk (even if this is a common or BSS.)
+  virtual size_t getSize() const = 0;
+
+  // Write this chunk to a mmap'ed file, assuming Buf is pointing to
+  // beginning of the file. Because this function may use RVA values
+  // of other chunks for relocations, you need to set them properly
+  // before calling this function.
+  virtual void writeTo(uint8_t *Buf) const {}
+
+  // The writer sets and uses the addresses.
+  uint64_t getRVA() const { return RVA; }
+  void setRVA(uint64_t V) { RVA = V; }
+
+  // Returns true if this has non-zero data. BSS chunks return
+  // false. If false is returned, the space occupied by this chunk
+  // will be filled with zeros.
+  virtual bool hasData() const { return true; }
+
+  // Returns readable/writable/executable bits.
+  virtual uint32_t getPermissions() const { return 0; }
+
+  // Returns the section name if this is a section chunk.
+  // It is illegal to call this function on non-section chunks.
+  virtual StringRef getSectionName() const {
+    llvm_unreachable("unimplemented getSectionName");
+  }
+
+  // An output section has pointers to chunks in the section, and each
+  // chunk has a back pointer to an output section.
+  void setOutputSection(OutputSection *O) { Out = O; }
+  OutputSection *getOutputSection() const { return Out; }
+
+  // Windows-specific.
+  // Collect all locations that contain absolute addresses for base relocations.
+  virtual void getBaserels(std::vector<Baserel> *Res) {}
+
+  // Returns a human-readable name of this chunk. Chunks are unnamed chunks of
+  // bytes, so this is used only for logging or debugging.
+  virtual StringRef getDebugName() { return ""; }
+
+  // The alignment of this chunk. The writer uses the value.
+  uint32_t Alignment = 1;
+
+protected:
+  Chunk(Kind K = OtherKind) : ChunkKind(K) {}
+  const Kind ChunkKind;
+
+  // The RVA of this chunk in the output. The writer sets a value.
+  uint64_t RVA = 0;
+
+  // The output section for this chunk.
+  OutputSection *Out = nullptr;
+
+public:
+  // The offset from beginning of the output section. The writer sets a value.
+  uint64_t OutputSectionOff = 0;
+};
+
+// A chunk corresponding a section of an input file.
+class SectionChunk final : public Chunk {
+  // Identical COMDAT Folding feature accesses section internal data.
+  friend class ICF;
+
+public:
+  class symbol_iterator : public llvm::iterator_adaptor_base<
+                              symbol_iterator, const coff_relocation *,
+                              std::random_access_iterator_tag, Symbol *> {
+    friend SectionChunk;
+
+    ObjFile *File;
+
+    symbol_iterator(ObjFile *File, const coff_relocation *I)
+        : symbol_iterator::iterator_adaptor_base(I), File(File) {}
+
+  public:
+    symbol_iterator() = default;
+
+    Symbol *operator*() const { return File->getSymbol(I->SymbolTableIndex); }
+  };
+
+  SectionChunk(ObjFile *File, const coff_section *Header);
+  static bool classof(const Chunk *C) { return C->kind() == SectionKind; }
+  size_t getSize() const override { return Header->SizeOfRawData; }
+  ArrayRef<uint8_t> getContents() const;
+  void writeTo(uint8_t *Buf) const override;
+  bool hasData() const override;
+  uint32_t getPermissions() const override;
+  StringRef getSectionName() const override { return SectionName; }
+  void getBaserels(std::vector<Baserel> *Res) override;
+  bool isCOMDAT() const;
+  void applyRelX64(uint8_t *Off, uint16_t Type, OutputSection *OS, uint64_t S,
+                   uint64_t P) const;
+  void applyRelX86(uint8_t *Off, uint16_t Type, OutputSection *OS, uint64_t S,
+                   uint64_t P) const;
+  void applyRelARM(uint8_t *Off, uint16_t Type, OutputSection *OS, uint64_t S,
+                   uint64_t P) const;
+  void applyRelARM64(uint8_t *Off, uint16_t Type, OutputSection *OS, uint64_t S,
+                     uint64_t P) const;
+
+  // Called if the garbage collector decides to not include this chunk
+  // in a final output. It's supposed to print out a log message to stdout.
+  void printDiscardedMessage() const;
+
+  // Adds COMDAT associative sections to this COMDAT section. A chunk
+  // and its children are treated as a group by the garbage collector.
+  void addAssociative(SectionChunk *Child);
+
+  StringRef getDebugName() override;
+
+  // Returns true if the chunk was not dropped by GC.
+  bool isLive() { return Live; }
+
+  // Used by the garbage collector.
+  void markLive() {
+    assert(Config->DoGC && "should only mark things live from GC");
+    assert(!isLive() && "Cannot mark an already live section!");
+    Live = true;
+  }
+
+  // True if this is a codeview debug info chunk. These will not be laid out in
+  // the image. Instead they will end up in the PDB, if one is requested.
+  bool isCodeView() const {
+    return SectionName == ".debug" || SectionName.startswith(".debug$");
+  }
+
+  // True if this is a DWARF debug info or exception handling chunk.
+  bool isDWARF() const {
+    return SectionName.startswith(".debug_") || SectionName == ".eh_frame";
+  }
+
+  // Allow iteration over the bodies of this chunk's relocated symbols.
+  llvm::iterator_range<symbol_iterator> symbols() const {
+    return llvm::make_range(symbol_iterator(File, Relocs.begin()),
+                            symbol_iterator(File, Relocs.end()));
+  }
+
+  // Allow iteration over the associated child chunks for this section.
+  ArrayRef<SectionChunk *> children() const { return AssocChildren; }
+
+  // A pointer pointing to a replacement for this chunk.
+  // Initially it points to "this" object. If this chunk is merged
+  // with other chunk by ICF, it points to another chunk,
+  // and this chunk is considrered as dead.
+  SectionChunk *Repl;
+
+  // The CRC of the contents as described in the COFF spec 4.5.5.
+  // Auxiliary Format 5: Section Definitions. Used for ICF.
+  uint32_t Checksum = 0;
+
+  const coff_section *Header;
+
+  // The file that this chunk was created from.
+  ObjFile *File;
+
+  // The COMDAT leader symbol if this is a COMDAT chunk.
+  DefinedRegular *Sym = nullptr;
+
+private:
+  StringRef SectionName;
+  std::vector<SectionChunk *> AssocChildren;
+  llvm::iterator_range<const coff_relocation *> Relocs;
+  size_t NumRelocs;
+
+  // Used by the garbage collector.
+  bool Live;
+
+  // Used for ICF (Identical COMDAT Folding)
+  void replace(SectionChunk *Other);
+  uint32_t Class[2] = {0, 0};
+};
+
+// A chunk for common symbols. Common chunks don't have actual data.
+class CommonChunk : public Chunk {
+public:
+  CommonChunk(const COFFSymbolRef Sym);
+  size_t getSize() const override { return Sym.getValue(); }
+  bool hasData() const override { return false; }
+  uint32_t getPermissions() const override;
+  StringRef getSectionName() const override { return ".bss"; }
+
+private:
+  const COFFSymbolRef Sym;
+};
+
+// A chunk for linker-created strings.
+class StringChunk : public Chunk {
+public:
+  explicit StringChunk(StringRef S) : Str(S) {}
+  size_t getSize() const override { return Str.size() + 1; }
+  void writeTo(uint8_t *Buf) const override;
+
+private:
+  StringRef Str;
+};
+
+static const uint8_t ImportThunkX86[] = {
+    0xff, 0x25, 0x00, 0x00, 0x00, 0x00, // JMP *0x0
+};
+
+static const uint8_t ImportThunkARM[] = {
+    0x40, 0xf2, 0x00, 0x0c, // mov.w ip, #0
+    0xc0, 0xf2, 0x00, 0x0c, // mov.t ip, #0
+    0xdc, 0xf8, 0x00, 0xf0, // ldr.w pc, [ip]
+};
+
+static const uint8_t ImportThunkARM64[] = {
+    0x10, 0x00, 0x00, 0x90, // adrp x16, #0
+    0x10, 0x02, 0x40, 0xf9, // ldr  x16, [x16]
+    0x00, 0x02, 0x1f, 0xd6, // br   x16
+};
+
+// Windows-specific.
+// A chunk for DLL import jump table entry. In a final output, it's
+// contents will be a JMP instruction to some __imp_ symbol.
+class ImportThunkChunkX64 : public Chunk {
+public:
+  explicit ImportThunkChunkX64(Defined *S);
+  size_t getSize() const override { return sizeof(ImportThunkX86); }
+  void writeTo(uint8_t *Buf) const override;
+
+private:
+  Defined *ImpSymbol;
+};
+
+class ImportThunkChunkX86 : public Chunk {
+public:
+  explicit ImportThunkChunkX86(Defined *S) : ImpSymbol(S) {}
+  size_t getSize() const override { return sizeof(ImportThunkX86); }
+  void getBaserels(std::vector<Baserel> *Res) override;
+  void writeTo(uint8_t *Buf) const override;
+
+private:
+  Defined *ImpSymbol;
+};
+
+class ImportThunkChunkARM : public Chunk {
+public:
+  explicit ImportThunkChunkARM(Defined *S) : ImpSymbol(S) {}
+  size_t getSize() const override { return sizeof(ImportThunkARM); }
+  void getBaserels(std::vector<Baserel> *Res) override;
+  void writeTo(uint8_t *Buf) const override;
+
+private:
+  Defined *ImpSymbol;
+};
+
+class ImportThunkChunkARM64 : public Chunk {
+public:
+  explicit ImportThunkChunkARM64(Defined *S) : ImpSymbol(S) {}
+  size_t getSize() const override { return sizeof(ImportThunkARM64); }
+  void writeTo(uint8_t *Buf) const override;
+
+private:
+  Defined *ImpSymbol;
+};
+
+// Windows-specific.
+// See comments for DefinedLocalImport class.
+class LocalImportChunk : public Chunk {
+public:
+  explicit LocalImportChunk(Defined *S) : Sym(S) {}
+  size_t getSize() const override;
+  void getBaserels(std::vector<Baserel> *Res) override;
+  void writeTo(uint8_t *Buf) const override;
+
+private:
+  Defined *Sym;
+};
+
+// Windows-specific.
+// A chunk for SEH table which contains RVAs of safe exception handler
+// functions. x86-only.
+class SEHTableChunk : public Chunk {
+public:
+  explicit SEHTableChunk(std::set<Defined *> S) : Syms(std::move(S)) {}
+  size_t getSize() const override { return Syms.size() * 4; }
+  void writeTo(uint8_t *Buf) const override;
+
+private:
+  std::set<Defined *> Syms;
+};
+
+// Windows-specific.
+// This class represents a block in .reloc section.
+// See the PE/COFF spec 5.6 for details.
+class BaserelChunk : public Chunk {
+public:
+  BaserelChunk(uint32_t Page, Baserel *Begin, Baserel *End);
+  size_t getSize() const override { return Data.size(); }
+  void writeTo(uint8_t *Buf) const override;
+
+private:
+  std::vector<uint8_t> Data;
+};
+
+class Baserel {
+public:
+  Baserel(uint32_t V, uint8_t Ty) : RVA(V), Type(Ty) {}
+  explicit Baserel(uint32_t V) : Baserel(V, getDefaultType()) {}
+  uint8_t getDefaultType();
+
+  uint32_t RVA;
+  uint8_t Type;
+};
+
+void applyMOV32T(uint8_t *Off, uint32_t V);
+void applyBranch24T(uint8_t *Off, int32_t V);
+
+} // namespace coff
+} // namespace lld
+
+#endif

external/llvm-project/lld/COFF/Config.h

@@ -0,0 +1,186 @@
+//===- Config.h -------------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_COFF_CONFIG_H
+#define LLD_COFF_CONFIG_H
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Object/COFF.h"
+#include "llvm/Support/CachePruning.h"
+#include <cstdint>
+#include <map>
+#include <set>
+#include <string>
+
+namespace lld {
+namespace coff {
+
+using llvm::COFF::IMAGE_FILE_MACHINE_UNKNOWN;
+using llvm::COFF::WindowsSubsystem;
+using llvm::StringRef;
+class DefinedAbsolute;
+class DefinedRelative;
+class StringChunk;
+class Symbol;
+
+// Short aliases.
+static const auto AMD64 = llvm::COFF::IMAGE_FILE_MACHINE_AMD64;
+static const auto ARM64 = llvm::COFF::IMAGE_FILE_MACHINE_ARM64;
+static const auto ARMNT = llvm::COFF::IMAGE_FILE_MACHINE_ARMNT;
+static const auto I386 = llvm::COFF::IMAGE_FILE_MACHINE_I386;
+
+// Represents an /export option.
+struct Export {
+  StringRef Name;       // N in /export:N or /export:E=N
+  StringRef ExtName;    // E in /export:E=N
+  Symbol *Sym = nullptr;
+  uint16_t Ordinal = 0;
+  bool Noname = false;
+  bool Data = false;
+  bool Private = false;
+  bool Constant = false;
+
+  // If an export is a form of /export:foo=dllname.bar, that means
+  // that foo should be exported as an alias to bar in the DLL.
+  // ForwardTo is set to "dllname.bar" part. Usually empty.
+  StringRef ForwardTo;
+  StringChunk *ForwardChunk = nullptr;
+
+  // True if this /export option was in .drectves section.
+  bool Directives = false;
+  StringRef SymbolName;
+  StringRef ExportName; // Name in DLL
+
+  bool operator==(const Export &E) {
+    return (Name == E.Name && ExtName == E.ExtName &&
+            Ordinal == E.Ordinal && Noname == E.Noname &&
+            Data == E.Data && Private == E.Private);
+  }
+};
+
+enum class DebugType {
+  None  = 0x0,
+  CV    = 0x1,  /// CodeView
+  PData = 0x2,  /// Procedure Data
+  Fixup = 0x4,  /// Relocation Table
+};
+
+// Global configuration.
+struct Configuration {
+  enum ManifestKind { SideBySide, Embed, No };
+  bool is64() { return Machine == AMD64 || Machine == ARM64; }
+
+  llvm::COFF::MachineTypes Machine = IMAGE_FILE_MACHINE_UNKNOWN;
+  bool Verbose = false;
+  WindowsSubsystem Subsystem = llvm::COFF::IMAGE_SUBSYSTEM_UNKNOWN;
+  Symbol *Entry = nullptr;
+  bool NoEntry = false;
+  std::string OutputFile;
+  std::string ImportName;
+  bool DoGC = true;
+  bool DoICF = true;
+  bool Relocatable = true;
+  bool Force = false;
+  bool Debug = false;
+  bool DebugDwarf = false;
+  bool DebugGHashes = false;
+  unsigned DebugTypes = static_cast<unsigned>(DebugType::None);
+  llvm::SmallString<128> PDBPath;
+  std::vector<llvm::StringRef> Argv;
+
+  // Symbols in this set are considered as live by the garbage collector.
+  std::vector<Symbol *> GCRoot;
+
+  std::set<StringRef> NoDefaultLibs;
+  bool NoDefaultLibAll = false;
+
+  // True if we are creating a DLL.
+  bool DLL = false;
+  StringRef Implib;
+  std::vector<Export> Exports;
+  std::set<std::string> DelayLoads;
+  std::map<std::string, int> DLLOrder;
+  Symbol *DelayLoadHelper = nullptr;
+
+  bool SaveTemps = false;
+
+  // Used for SafeSEH.
+  Symbol *SEHTable = nullptr;
+  Symbol *SEHCount = nullptr;
+
+  // Used for /opt:lldlto=N
+  unsigned LTOOptLevel = 2;
+
+  // Used for /opt:lldltojobs=N
+  unsigned LTOJobs = 0;
+  // Used for /opt:lldltopartitions=N
+  unsigned LTOPartitions = 1;
+
+  // Used for /opt:lldltocache=path
+  StringRef LTOCache;
+  // Used for /opt:lldltocachepolicy=policy
+  llvm::CachePruningPolicy LTOCachePolicy;
+
+  // Used for /merge:from=to (e.g. /merge:.rdata=.text)
+  std::map<StringRef, StringRef> Merge;
+
+  // Used for /section=.name,{DEKPRSW} to set section attributes.
+  std::map<StringRef, uint32_t> Section;
+
+  // Options for manifest files.
+  ManifestKind Manifest = No;
+  int ManifestID = 1;
+  StringRef ManifestDependency;
+  bool ManifestUAC = true;
+  std::vector<std::string> ManifestInput;
+  StringRef ManifestLevel = "'asInvoker'";
+  StringRef ManifestUIAccess = "'false'";
+  StringRef ManifestFile;
+
+  // Used for /aligncomm.
+  std::map<std::string, int> AlignComm;
+
+  // Used for /failifmismatch.
+  std::map<StringRef, StringRef> MustMatch;
+
+  // Used for /alternatename.
+  std::map<StringRef, StringRef> AlternateNames;
+
+  // Used for /lldmap.
+  std::string MapFile;
+
+  uint64_t ImageBase = -1;
+  uint64_t StackReserve = 1024 * 1024;
+  uint64_t StackCommit = 4096;
+  uint64_t HeapReserve = 1024 * 1024;
+  uint64_t HeapCommit = 4096;
+  uint32_t MajorImageVersion = 0;
+  uint32_t MinorImageVersion = 0;
+  uint32_t MajorOSVersion = 6;
+  uint32_t MinorOSVersion = 0;
+  bool CanExitEarly = false;
+  bool DynamicBase = true;
+  bool AllowBind = true;
+  bool NxCompat = true;
+  bool AllowIsolation = true;
+  bool TerminalServerAware = true;
+  bool LargeAddressAware = false;
+  bool HighEntropyVA = false;
+  bool AppContainer = false;
+  bool MinGW = false;
+  bool WarnLocallyDefinedImported = true;
+  bool KillAt = false;
+};
+
+extern Configuration *Config;
+
+} // namespace coff
+} // namespace lld
+
+#endif

external/llvm-project/lld/COFF/DLL.h

@@ -0,0 +1,84 @@
+//===- DLL.h ----------------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_COFF_DLL_H
+#define LLD_COFF_DLL_H
+
+#include "Chunks.h"
+#include "Symbols.h"
+
+namespace lld {
+namespace coff {
+
+// Windows-specific.
+// IdataContents creates all chunks for the DLL import table.
+// You are supposed to call add() to add symbols and then
+// call getChunks() to get a list of chunks.
+class IdataContents {
+public:
+  void add(DefinedImportData *Sym) { Imports.push_back(Sym); }
+  bool empty() { return Imports.empty(); }
+  std::vector<Chunk *> getChunks();
+
+  uint64_t getDirRVA() { return Dirs[0]->getRVA(); }
+  uint64_t getDirSize();
+  uint64_t getIATRVA() { return Addresses[0]->getRVA(); }
+  uint64_t getIATSize();
+
+private:
+  void create();
+
+  std::vector<DefinedImportData *> Imports;
+  std::vector<Chunk *> Dirs;
+  std::vector<Chunk *> Lookups;
+  std::vector<Chunk *> Addresses;
+  std::vector<Chunk *> Hints;
+  std::vector<Chunk *> DLLNames;
+};
+
+// Windows-specific.
+// DelayLoadContents creates all chunks for the delay-load DLL import table.
+class DelayLoadContents {
+public:
+  void add(DefinedImportData *Sym) { Imports.push_back(Sym); }
+  bool empty() { return Imports.empty(); }
+  void create(Defined *Helper);
+  std::vector<Chunk *> getChunks();
+  std::vector<Chunk *> getDataChunks();
+  ArrayRef<Chunk *> getCodeChunks() { return Thunks; }
+
+  uint64_t getDirRVA() { return Dirs[0]->getRVA(); }
+  uint64_t getDirSize();
+
+private:
+  Chunk *newThunkChunk(DefinedImportData *S, Chunk *Dir);
+
+  Defined *Helper;
+  std::vector<DefinedImportData *> Imports;
+  std::vector<Chunk *> Dirs;
+  std::vector<Chunk *> ModuleHandles;
+  std::vector<Chunk *> Addresses;
+  std::vector<Chunk *> Names;
+  std::vector<Chunk *> HintNames;
+  std::vector<Chunk *> Thunks;
+  std::vector<Chunk *> DLLNames;
+};
+
+// Windows-specific.
+// EdataContents creates all chunks for the DLL export table.
+class EdataContents {
+public:
+  EdataContents();
+  std::vector<Chunk *> Chunks;
+};
+
+} // namespace coff
+} // namespace lld
+
+#endif

external/llvm-project/lld/COFF/Driver.h

@@ -0,0 +1,196 @@
+//===- Driver.h -------------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_COFF_DRIVER_H
+#define LLD_COFF_DRIVER_H
+
+#include "Config.h"
+#include "SymbolTable.h"
+#include "lld/Common/LLVM.h"
+#include "lld/Common/Reproduce.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/StringSet.h"
+#include "llvm/Object/Archive.h"
+#include "llvm/Object/COFF.h"
+#include "llvm/Option/Arg.h"
+#include "llvm/Option/ArgList.h"
+#include "llvm/Support/TarWriter.h"
+#include <memory>
+#include <set>
+#include <vector>
+
+namespace lld {
+namespace coff {
+
+class LinkerDriver;
+extern LinkerDriver *Driver;
+
+using llvm::COFF::MachineTypes;
+using llvm::COFF::WindowsSubsystem;
+using llvm::Optional;
+
+// Implemented in MarkLive.cpp.
+void markLive(ArrayRef<Chunk *> Chunks);
+
+// Implemented in ICF.cpp.
+void doICF(ArrayRef<Chunk *> Chunks);
+
+class COFFOptTable : public llvm::opt::OptTable {
+public:
+  COFFOptTable();
+};
+
+class ArgParser {
+public:
+  // Concatenate LINK environment variable and given arguments and parse them.
+  llvm::opt::InputArgList parseLINK(std::vector<const char *> Args);
+
+  // Tokenizes a given string and then parses as command line options.
+  llvm::opt::InputArgList parse(StringRef S) { return parse(tokenize(S)); }
+
+  // Tokenizes a given string and then parses as command line options in
+  // .drectve section.
+  llvm::opt::InputArgList parseDirectives(StringRef S);
+
+private:
+  // Parses command line options.
+  llvm::opt::InputArgList parse(llvm::ArrayRef<const char *> Args);
+
+  std::vector<const char *> tokenize(StringRef S);
+
+  COFFOptTable Table;
+};
+
+class LinkerDriver {
+public:
+  void link(llvm::ArrayRef<const char *> Args);
+
+  // Used by the resolver to parse .drectve section contents.
+  void parseDirectives(StringRef S);
+
+  // Used by ArchiveFile to enqueue members.
+  void enqueueArchiveMember(const Archive::Child &C, StringRef SymName,
+                            StringRef ParentName);
+
+  MemoryBufferRef takeBuffer(std::unique_ptr<MemoryBuffer> MB);
+
+private:
+  std::unique_ptr<llvm::TarWriter> Tar; // for /linkrepro
+
+  // Opens a file. Path has to be resolved already.
+  MemoryBufferRef openFile(StringRef Path);
+
+  // Searches a file from search paths.
+  Optional<StringRef> findFile(StringRef Filename);
+  Optional<StringRef> findLib(StringRef Filename);
+  StringRef doFindFile(StringRef Filename);
+  StringRef doFindLib(StringRef Filename);
+
+  // Parses LIB environment which contains a list of search paths.
+  void addLibSearchPaths();
+
+  // Library search path. The first element is always "" (current directory).
+  std::vector<StringRef> SearchPaths;
+  std::set<std::string> VisitedFiles;
+  std::set<std::string> VisitedLibs;
+
+  Symbol *addUndefined(StringRef Sym);
+  StringRef mangle(StringRef Sym);
+
+  // Windows specific -- "main" is not the only main function in Windows.
+  // You can choose one from these four -- {w,}{WinMain,main}.
+  // There are four different entry point functions for them,
+  // {w,}{WinMain,main}CRTStartup, respectively. The linker needs to
+  // choose the right one depending on which "main" function is defined.
+  // This function looks up the symbol table and resolve corresponding
+  // entry point name.
+  StringRef findDefaultEntry();
+  WindowsSubsystem inferSubsystem();
+
+  void invokeMSVC(llvm::opt::InputArgList &Args);
+
+  void addBuffer(std::unique_ptr<MemoryBuffer> MB, bool WholeArchive);
+  void addArchiveBuffer(MemoryBufferRef MBRef, StringRef SymName,
+                        StringRef ParentName);
+
+  void enqueuePath(StringRef Path, bool WholeArchive);
+
+  void enqueueTask(std::function<void()> Task);
+  bool run();
+
+  std::list<std::function<void()>> TaskQueue;
+  std::vector<StringRef> FilePaths;
+  std::vector<MemoryBufferRef> Resources;
+
+  llvm::StringSet<> DirectivesExports;
+};
+
+// Functions below this line are defined in DriverUtils.cpp.
+
+void printHelp(const char *Argv0);
+
+// For /machine option.
+MachineTypes getMachineType(StringRef Arg);
+StringRef machineToStr(MachineTypes MT);
+
+// Parses a string in the form of "<integer>[,<integer>]".
+void parseNumbers(StringRef Arg, uint64_t *Addr, uint64_t *Size = nullptr);
+
+// Parses a string in the form of "<integer>[.<integer>]".
+// Minor's default value is 0.
+void parseVersion(StringRef Arg, uint32_t *Major, uint32_t *Minor);
+
+// Parses a string in the form of "<subsystem>[,<integer>[.<integer>]]".
+void parseSubsystem(StringRef Arg, WindowsSubsystem *Sys, uint32_t *Major,
+                    uint32_t *Minor);
+
+void parseAlternateName(StringRef);
+void parseMerge(StringRef);
+void parseSection(StringRef);
+void parseAligncomm(StringRef);
+
+// Parses a string in the form of "EMBED[,=<integer>]|NO".
+void parseManifest(StringRef Arg);
+
+// Parses a string in the form of "level=<string>|uiAccess=<string>"
+void parseManifestUAC(StringRef Arg);
+
+// Create a resource file containing a manifest XML.
+std::unique_ptr<MemoryBuffer> createManifestRes();
+void createSideBySideManifest();
+
+// Used for dllexported symbols.
+Export parseExport(StringRef Arg);
+void fixupExports();
+void assignExportOrdinals();
+
+// Parses a string in the form of "key=value" and check
+// if value matches previous values for the key.
+// This feature used in the directive section to reject
+// incompatible objects.
+void checkFailIfMismatch(StringRef Arg);
+
+// Convert Windows resource files (.res files) to a .obj file.
+MemoryBufferRef convertResToCOFF(ArrayRef<MemoryBufferRef> MBs);
+
+void runMSVCLinker(std::string Rsp, ArrayRef<StringRef> Objects);
+
+// Create enum with OPT_xxx values for each option in Options.td
+enum {
+  OPT_INVALID = 0,
+#define OPTION(_1, _2, ID, _4, _5, _6, _7, _8, _9, _10, _11, _12) OPT_##ID,
+#include "Options.inc"
+#undef OPTION
+};
+
+} // namespace coff
+} // namespace lld
+
+#endif

external/llvm-project/lld/COFF/ICF.cpp

@@ -0,0 +1,263 @@
+//===- ICF.cpp ------------------------------------------------------------===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// ICF is short for Identical Code Folding. That is a size optimization to
+// identify and merge two or more read-only sections (typically functions)
+// that happened to have the same contents. It usually reduces output size
+// by a few percent.
+//
+// On Windows, ICF is enabled by default.
+//
+// See ELF/ICF.cpp for the details about the algortihm.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Chunks.h"
+#include "Symbols.h"
+#include "lld/Common/ErrorHandler.h"
+#include "llvm/ADT/Hashing.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/Parallel.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <atomic>
+#include <vector>
+
+using namespace llvm;
+
+namespace lld {
+namespace coff {
+
+class ICF {
+public:
+  void run(ArrayRef<Chunk *> V);
+
+private:
+  void segregate(size_t Begin, size_t End, bool Constant);
+
+  bool equalsConstant(const SectionChunk *A, const SectionChunk *B);
+  bool equalsVariable(const SectionChunk *A, const SectionChunk *B);
+
+  uint32_t getHash(SectionChunk *C);
+  bool isEligible(SectionChunk *C);
+
+  size_t findBoundary(size_t Begin, size_t End);
+
+  void forEachClassRange(size_t Begin, size_t End,
+                         std::function<void(size_t, size_t)> Fn);
+
+  void forEachClass(std::function<void(size_t, size_t)> Fn);
+
+  std::vector<SectionChunk *> Chunks;
+  int Cnt = 0;
+  std::atomic<bool> Repeat = {false};
+};
+
+// Returns a hash value for S.
+uint32_t ICF::getHash(SectionChunk *C) {
+  return hash_combine(C->getPermissions(), C->SectionName, C->NumRelocs,
+                      C->Alignment, uint32_t(C->Header->SizeOfRawData),
+                      C->Checksum, C->getContents());
+}
+
+// Returns true if section S is subject of ICF.
+//
+// Microsoft's documentation
+// (https://msdn.microsoft.com/en-us/library/bxwfs976.aspx; visited April
+// 2017) says that /opt:icf folds both functions and read-only data.
+// Despite that, the MSVC linker folds only functions. We found
+// a few instances of programs that are not safe for data merging.
+// Therefore, we merge only functions just like the MSVC tool. However, we merge
+// identical .xdata sections, because the address of unwind information is
+// insignificant to the user program and the Visual C++ linker does this.
+bool ICF::isEligible(SectionChunk *C) {
+  // Non-comdat chunks, dead chunks, and writable chunks are not elegible.
+  bool Writable = C->getPermissions() & llvm::COFF::IMAGE_SCN_MEM_WRITE;
+  if (!C->isCOMDAT() || !C->isLive() || Writable)
+    return false;
+
+  // Code sections are eligible.
+  if (C->getPermissions() & llvm::COFF::IMAGE_SCN_MEM_EXECUTE)
+    return true;
+
+  // .xdata unwind info sections are eligble.
+  return C->getSectionName().split('$').first == ".xdata";
+}
+
+// Split an equivalence class into smaller classes.
+void ICF::segregate(size_t Begin, size_t End, bool Constant) {
+  while (Begin < End) {
+    // Divide [Begin, End) into two. Let Mid be the start index of the
+    // second group.
+    auto Bound = std::stable_partition(
+        Chunks.begin() + Begin + 1, Chunks.begin() + End, [&](SectionChunk *S) {
+          if (Constant)
+            return equalsConstant(Chunks[Begin], S);
+          return equalsVariable(Chunks[Begin], S);
+        });
+    size_t Mid = Bound - Chunks.begin();
+
+    // Split [Begin, End) into [Begin, Mid) and [Mid, End). We use Mid as an
+    // equivalence class ID because every group ends with a unique index.
+    for (size_t I = Begin; I < Mid; ++I)
+      Chunks[I]->Class[(Cnt + 1) % 2] = Mid;
+
+    // If we created a group, we need to iterate the main loop again.
+    if (Mid != End)
+      Repeat = true;
+
+    Begin = Mid;
+  }
+}
+
+// Compare "non-moving" part of two sections, namely everything
+// except relocation targets.
+bool ICF::equalsConstant(const SectionChunk *A, const SectionChunk *B) {
+  if (A->NumRelocs != B->NumRelocs)
+    return false;
+
+  // Compare relocations.
+  auto Eq = [&](const coff_relocation &R1, const coff_relocation &R2) {
+    if (R1.Type != R2.Type ||
+        R1.VirtualAddress != R2.VirtualAddress) {
+      return false;
+    }
+    Symbol *B1 = A->File->getSymbol(R1.SymbolTableIndex);
+    Symbol *B2 = B->File->getSymbol(R2.SymbolTableIndex);
+    if (B1 == B2)
+      return true;
+    if (auto *D1 = dyn_cast<DefinedRegular>(B1))
+      if (auto *D2 = dyn_cast<DefinedRegular>(B2))
+        return D1->getValue() == D2->getValue() &&
+               D1->getChunk()->Class[Cnt % 2] == D2->getChunk()->Class[Cnt % 2];
+    return false;
+  };
+  if (!std::equal(A->Relocs.begin(), A->Relocs.end(), B->Relocs.begin(), Eq))
+    return false;
+
+  // Compare section attributes and contents.
+  return A->getPermissions() == B->getPermissions() &&
+         A->SectionName == B->SectionName && A->Alignment == B->Alignment &&
+         A->Header->SizeOfRawData == B->Header->SizeOfRawData &&
+         A->Checksum == B->Checksum && A->getContents() == B->getContents();
+}
+
+// Compare "moving" part of two sections, namely relocation targets.
+bool ICF::equalsVariable(const SectionChunk *A, const SectionChunk *B) {
+  // Compare relocations.
+  auto Eq = [&](const coff_relocation &R1, const coff_relocation &R2) {
+    Symbol *B1 = A->File->getSymbol(R1.SymbolTableIndex);
+    Symbol *B2 = B->File->getSymbol(R2.SymbolTableIndex);
+    if (B1 == B2)
+      return true;
+    if (auto *D1 = dyn_cast<DefinedRegular>(B1))
+      if (auto *D2 = dyn_cast<DefinedRegular>(B2))
+        return D1->getChunk()->Class[Cnt % 2] == D2->getChunk()->Class[Cnt % 2];
+    return false;
+  };
+  return std::equal(A->Relocs.begin(), A->Relocs.end(), B->Relocs.begin(), Eq);
+}
+
+size_t ICF::findBoundary(size_t Begin, size_t End) {
+  for (size_t I = Begin + 1; I < End; ++I)
+    if (Chunks[Begin]->Class[Cnt % 2] != Chunks[I]->Class[Cnt % 2])
+      return I;
+  return End;
+}
+
+void ICF::forEachClassRange(size_t Begin, size_t End,
+                            std::function<void(size_t, size_t)> Fn) {
+  if (Begin > 0)
+    Begin = findBoundary(Begin - 1, End);
+
+  while (Begin < End) {
+    size_t Mid = findBoundary(Begin, Chunks.size());
+    Fn(Begin, Mid);
+    Begin = Mid;
+  }
+}
+
+// Call Fn on each class group.
+void ICF::forEachClass(std::function<void(size_t, size_t)> Fn) {
+  // If the number of sections are too small to use threading,
+  // call Fn sequentially.
+  if (Chunks.size() < 1024) {
+    forEachClassRange(0, Chunks.size(), Fn);
+    ++Cnt;
+    return;
+  }
+
+  // Split sections into 256 shards and call Fn in parallel.
+  size_t NumShards = 256;
+  size_t Step = Chunks.size() / NumShards;
+  for_each_n(parallel::par, size_t(0), NumShards, [&](size_t I) {
+    size_t End = (I == NumShards - 1) ? Chunks.size() : (I + 1) * Step;
+    forEachClassRange(I * Step, End, Fn);
+  });
+  ++Cnt;
+}
+
+// Merge identical COMDAT sections.
+// Two sections are considered the same if their section headers,
+// contents and relocations are all the same.
+void ICF::run(ArrayRef<Chunk *> Vec) {
+  // Collect only mergeable sections and group by hash value.
+  uint32_t NextId = 1;
+  for (Chunk *C : Vec) {
+    if (auto *SC = dyn_cast<SectionChunk>(C)) {
+      if (isEligible(SC))
+        Chunks.push_back(SC);
+      else
+        SC->Class[0] = NextId++;
+    }
+  }
+
+  // Initially, we use hash values to partition sections.
+  for_each(parallel::par, Chunks.begin(), Chunks.end(), [&](SectionChunk *SC) {
+    // Set MSB to 1 to avoid collisions with non-hash classs.
+    SC->Class[0] = getHash(SC) | (1 << 31);
+  });
+
+  // From now on, sections in Chunks are ordered so that sections in
+  // the same group are consecutive in the vector.
+  std::stable_sort(Chunks.begin(), Chunks.end(),
+                   [](SectionChunk *A, SectionChunk *B) {
+                     return A->Class[0] < B->Class[0];
+                   });
+
+  // Compare static contents and assign unique IDs for each static content.
+  forEachClass([&](size_t Begin, size_t End) { segregate(Begin, End, true); });
+
+  // Split groups by comparing relocations until convergence is obtained.
+  do {
+    Repeat = false;
+    forEachClass(
+        [&](size_t Begin, size_t End) { segregate(Begin, End, false); });
+  } while (Repeat);
+
+  log("ICF needed " + Twine(Cnt) + " iterations");
+
+  // Merge sections in the same classs.
+  forEachClass([&](size_t Begin, size_t End) {
+    if (End - Begin == 1)
+      return;
+
+    log("Selected " + Chunks[Begin]->getDebugName());
+    for (size_t I = Begin + 1; I < End; ++I) {
+      log("  Removed " + Chunks[I]->getDebugName());
+      Chunks[Begin]->replace(Chunks[I]);
+    }
+  });
+}
+
+// Entry point to ICF.
+void doICF(ArrayRef<Chunk *> Chunks) { ICF().run(Chunks); }
+
+} // namespace coff
+} // namespace lld

external/llvm-project/lld/COFF/InputFiles.h

@@ -0,0 +1,235 @@
+//===- InputFiles.h ---------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_COFF_INPUT_FILES_H
+#define LLD_COFF_INPUT_FILES_H
+
+#include "Config.h"
+#include "lld/Common/LLVM.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/LTO/LTO.h"
+#include "llvm/Object/Archive.h"
+#include "llvm/Object/COFF.h"
+#include "llvm/Support/StringSaver.h"
+#include <memory>
+#include <set>
+#include <vector>
+
+namespace llvm {
+namespace pdb {
+class DbiModuleDescriptorBuilder;
+}
+}
+
+namespace lld {
+namespace coff {
+
+std::vector<MemoryBufferRef> getArchiveMembers(llvm::object::Archive *File);
+
+using llvm::COFF::IMAGE_FILE_MACHINE_UNKNOWN;
+using llvm::COFF::MachineTypes;
+using llvm::object::Archive;
+using llvm::object::COFFObjectFile;
+using llvm::object::COFFSymbolRef;
+using llvm::object::coff_import_header;
+using llvm::object::coff_section;
+
+class Chunk;
+class Defined;
+class DefinedImportData;
+class DefinedImportThunk;
+class Lazy;
+class SectionChunk;
+class Symbol;
+class Undefined;
+
+// The root class of input files.
+class InputFile {
+public:
+  enum Kind { ArchiveKind, ObjectKind, ImportKind, BitcodeKind };
+  Kind kind() const { return FileKind; }
+  virtual ~InputFile() {}
+
+  // Returns the filename.
+  StringRef getName() const { return MB.getBufferIdentifier(); }
+
+  // Reads a file (the constructor doesn't do that).
+  virtual void parse() = 0;
+
+  // Returns the CPU type this file was compiled to.
+  virtual MachineTypes getMachineType() { return IMAGE_FILE_MACHINE_UNKNOWN; }
+
+  MemoryBufferRef MB;
+
+  // An archive file name if this file is created from an archive.
+  StringRef ParentName;
+
+  // Returns .drectve section contents if exist.
+  StringRef getDirectives() { return StringRef(Directives).trim(); }
+
+protected:
+  InputFile(Kind K, MemoryBufferRef M) : MB(M), FileKind(K) {}
+
+  std::string Directives;
+
+private:
+  const Kind FileKind;
+};
+
+// .lib or .a file.
+class ArchiveFile : public InputFile {
+public:
+  explicit ArchiveFile(MemoryBufferRef M);
+  static bool classof(const InputFile *F) { return F->kind() == ArchiveKind; }
+  void parse() override;
+
+  // Enqueues an archive member load for the given symbol. If we've already
+  // enqueued a load for the same archive member, this function does nothing,
+  // which ensures that we don't load the same member more than once.
+  void addMember(const Archive::Symbol *Sym);
+
+private:
+  std::unique_ptr<Archive> File;
+  std::string Filename;
+  llvm::DenseSet<uint64_t> Seen;
+};
+
+// .obj or .o file. This may be a member of an archive file.
+class ObjFile : public InputFile {
+public:
+  explicit ObjFile(MemoryBufferRef M) : InputFile(ObjectKind, M) {}
+  static bool classof(const InputFile *F) { return F->kind() == ObjectKind; }
+  void parse() override;
+  MachineTypes getMachineType() override;
+  ArrayRef<Chunk *> getChunks() { return Chunks; }
+  ArrayRef<SectionChunk *> getDebugChunks() { return DebugChunks; }
+  ArrayRef<Symbol *> getSymbols() { return Symbols; }
+
+  // Returns a Symbol object for the SymbolIndex'th symbol in the
+  // underlying object file.
+  Symbol *getSymbol(uint32_t SymbolIndex) {
+    return Symbols[SymbolIndex];
+  }
+
+  // Returns the underying COFF file.
+  COFFObjectFile *getCOFFObj() { return COFFObj.get(); }
+
+  static std::vector<ObjFile *> Instances;
+
+  // True if this object file is compatible with SEH.
+  // COFF-specific and x86-only.
+  bool SEHCompat = false;
+
+  // The symbol table indexes of the safe exception handlers.
+  // COFF-specific and x86-only.
+  ArrayRef<llvm::support::ulittle32_t> SXData;
+
+  // Pointer to the PDB module descriptor builder. Various debug info records
+  // will reference object files by "module index", which is here. Things like
+  // source files and section contributions are also recorded here. Will be null
+  // if we are not producing a PDB.
+  llvm::pdb::DbiModuleDescriptorBuilder *ModuleDBI = nullptr;
+
+private:
+  void initializeChunks();
+  void initializeSymbols();
+
+  SectionChunk *
+  readSection(uint32_t SectionNumber,
+              const llvm::object::coff_aux_section_definition *Def);
+
+  void readAssociativeDefinition(
+      COFFSymbolRef COFFSym,
+      const llvm::object::coff_aux_section_definition *Def);
+
+  llvm::Optional<Symbol *>
+  createDefined(COFFSymbolRef Sym,
+                std::vector<const llvm::object::coff_aux_section_definition *>
+                    &ComdatDefs);
+  Symbol *createRegular(COFFSymbolRef Sym);
+  Symbol *createUndefined(COFFSymbolRef Sym);
+
+  std::unique_ptr<COFFObjectFile> COFFObj;
+
+  // List of all chunks defined by this file. This includes both section
+  // chunks and non-section chunks for common symbols.
+  std::vector<Chunk *> Chunks;
+
+  // CodeView debug info sections.
+  std::vector<SectionChunk *> DebugChunks;
+
+  // This vector contains the same chunks as Chunks, but they are
+  // indexed such that you can get a SectionChunk by section index.
+  // Nonexistent section indices are filled with null pointers.
+  // (Because section number is 1-based, the first slot is always a
+  // null pointer.)
+  std::vector<SectionChunk *> SparseChunks;
+
+  // This vector contains a list of all symbols defined or referenced by this
+  // file. They are indexed such that you can get a Symbol by symbol
+  // index. Nonexistent indices (which are occupied by auxiliary
+  // symbols in the real symbol table) are filled with null pointers.
+  std::vector<Symbol *> Symbols;
+};
+
+// This type represents import library members that contain DLL names
+// and symbols exported from the DLLs. See Microsoft PE/COFF spec. 7
+// for details about the format.
+class ImportFile : public InputFile {
+public:
+  explicit ImportFile(MemoryBufferRef M)
+      : InputFile(ImportKind, M), Live(!Config->DoGC) {}
+
+  static bool classof(const InputFile *F) { return F->kind() == ImportKind; }
+
+  static std::vector<ImportFile *> Instances;
+
+  DefinedImportData *ImpSym = nullptr;
+  DefinedImportThunk *ThunkSym = nullptr;
+  std::string DLLName;
+
+private:
+  void parse() override;
+
+public:
+  StringRef ExternalName;
+  const coff_import_header *Hdr;
+  Chunk *Location = nullptr;
+
+  // We want to eliminate dllimported symbols if no one actually refers them.
+  // This "Live" bit is used to keep track of which import library members
+  // are actually in use.
+  //
+  // If the Live bit is turned off by MarkLive, Writer will ignore dllimported
+  // symbols provided by this import library member.
+  bool Live;
+};
+
+// Used for LTO.
+class BitcodeFile : public InputFile {
+public:
+  explicit BitcodeFile(MemoryBufferRef M) : InputFile(BitcodeKind, M) {}
+  static bool classof(const InputFile *F) { return F->kind() == BitcodeKind; }
+  ArrayRef<Symbol *> getSymbols() { return SymbolBodies; }
+  MachineTypes getMachineType() override;
+  static std::vector<BitcodeFile *> Instances;
+  std::unique_ptr<llvm::lto::InputFile> Obj;
+
+private:
+  void parse() override;
+
+  std::vector<Symbol *> SymbolBodies;
+};
+} // namespace coff
+
+std::string toString(const coff::InputFile *File);
+} // namespace lld
+
+#endif

external/llvm-project/lld/COFF/LTO.cpp

@@ -0,0 +1,163 @@
+//===- LTO.cpp ------------------------------------------------------------===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "LTO.h"
+#include "Config.h"
+#include "InputFiles.h"
+#include "Symbols.h"
+#include "lld/Common/ErrorHandler.h"
+#include "lld/Common/TargetOptionsCommandFlags.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/IR/DiagnosticPrinter.h"
+#include "llvm/LTO/Caching.h"
+#include "llvm/LTO/Config.h"
+#include "llvm/LTO/LTO.h"
+#include "llvm/Object/SymbolicFile.h"
+#include "llvm/Support/CodeGen.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <cstddef>
+#include <memory>
+#include <string>
+#include <system_error>
+#include <vector>
+
+using namespace llvm;
+using namespace llvm::object;
+
+using namespace lld;
+using namespace lld::coff;
+
+static void diagnosticHandler(const DiagnosticInfo &DI) {
+  SmallString<128> ErrStorage;
+  raw_svector_ostream OS(ErrStorage);
+  DiagnosticPrinterRawOStream DP(OS);
+  DI.print(DP);
+  warn(ErrStorage);
+}
+
+static void checkError(Error E) {
+  handleAllErrors(std::move(E),
+                  [&](ErrorInfoBase &EIB) { error(EIB.message()); });
+}
+
+static void saveBuffer(StringRef Buffer, const Twine &Path) {
+  std::error_code EC;
+  raw_fd_ostream OS(Path.str(), EC, sys::fs::OpenFlags::F_None);
+  if (EC)
+    error("cannot create " + Path + ": " + EC.message());
+  OS << Buffer;
+}
+
+static std::unique_ptr<lto::LTO> createLTO() {
+  lto::Config Conf;
+  Conf.Options = InitTargetOptionsFromCodeGenFlags();
+  // Use static reloc model on 32-bit x86 because it usually results in more
+  // compact code, and because there are also known code generation bugs when
+  // using the PIC model (see PR34306).
+  if (Config->Machine == COFF::IMAGE_FILE_MACHINE_I386)
+    Conf.RelocModel = Reloc::Static;
+  else
+    Conf.RelocModel = Reloc::PIC_;
+  Conf.DisableVerify = true;
+  Conf.DiagHandler = diagnosticHandler;
+  Conf.OptLevel = Config->LTOOptLevel;
+  if (Config->SaveTemps)
+    checkError(Conf.addSaveTemps(std::string(Config->OutputFile) + ".",
+                                 /*UseInputModulePath*/ true));
+  lto::ThinBackend Backend;
+  if (Config->LTOJobs != 0)
+    Backend = lto::createInProcessThinBackend(Config->LTOJobs);
+  return llvm::make_unique<lto::LTO>(std::move(Conf), Backend,
+                                     Config->LTOPartitions);
+}
+
+BitcodeCompiler::BitcodeCompiler() : LTOObj(createLTO()) {}
+
+BitcodeCompiler::~BitcodeCompiler() = default;
+
+static void undefine(Symbol *S) { replaceSymbol<Undefined>(S, S->getName()); }
+
+void BitcodeCompiler::add(BitcodeFile &F) {
+  lto::InputFile &Obj = *F.Obj;
+  unsigned SymNum = 0;
+  std::vector<Symbol *> SymBodies = F.getSymbols();
+  std::vector<lto::SymbolResolution> Resols(SymBodies.size());
+
+  // Provide a resolution to the LTO API for each symbol.
+  for (const lto::InputFile::Symbol &ObjSym : Obj.symbols()) {
+    Symbol *Sym = SymBodies[SymNum];
+    lto::SymbolResolution &R = Resols[SymNum];
+    ++SymNum;
+
+    // Ideally we shouldn't check for SF_Undefined but currently IRObjectFile
+    // reports two symbols for module ASM defined. Without this check, lld
+    // flags an undefined in IR with a definition in ASM as prevailing.
+    // Once IRObjectFile is fixed to report only one symbol this hack can
+    // be removed.
+    R.Prevailing = !ObjSym.isUndefined() && Sym->getFile() == &F;
+    R.VisibleToRegularObj = Sym->IsUsedInRegularObj;
+    if (R.Prevailing)
+      undefine(Sym);
+  }
+  checkError(LTOObj->add(std::move(F.Obj), Resols));
+}
+
+// Merge all the bitcode files we have seen, codegen the result
+// and return the resulting objects.
+std::vector<StringRef> BitcodeCompiler::compile() {
+  unsigned MaxTasks = LTOObj->getMaxTasks();
+  Buff.resize(MaxTasks);
+  Files.resize(MaxTasks);
+
+  // The /lldltocache option specifies the path to a directory in which to cache
+  // native object files for ThinLTO incremental builds. If a path was
+  // specified, configure LTO to use it as the cache directory.
+  lto::NativeObjectCache Cache;
+  if (!Config->LTOCache.empty())
+    Cache = check(
+        lto::localCache(Config->LTOCache,
+                        [&](size_t Task, std::unique_ptr<MemoryBuffer> MB,
+                            StringRef Path) { Files[Task] = std::move(MB); }));
+
+  checkError(LTOObj->run(
+      [&](size_t Task) {
+        return llvm::make_unique<lto::NativeObjectStream>(
+            llvm::make_unique<raw_svector_ostream>(Buff[Task]));
+      },
+      Cache));
+
+  if (!Config->LTOCache.empty())
+    pruneCache(Config->LTOCache, Config->LTOCachePolicy);
+
+  std::vector<StringRef> Ret;
+  for (unsigned I = 0; I != MaxTasks; ++I) {
+    if (Buff[I].empty())
+      continue;
+    if (Config->SaveTemps) {
+      if (I == 0)
+        saveBuffer(Buff[I], Config->OutputFile + ".lto.obj");
+      else
+        saveBuffer(Buff[I], Config->OutputFile + Twine(I) + ".lto.obj");
+    }
+    Ret.emplace_back(Buff[I].data(), Buff[I].size());
+  }
+
+  for (std::unique_ptr<MemoryBuffer> &File : Files)
+    if (File)
+      Ret.push_back(File->getBuffer());
+
+  return Ret;
+}

external/llvm-project/lld/COFF/LTO.h

@@ -0,0 +1,57 @@
+//===- LTO.h ----------------------------------------------------*- C++ -*-===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides a way to combine bitcode files into one COFF
+// file by compiling them using LLVM.
+//
+// If LTO is in use, your input files are not in regular COFF files
+// but instead LLVM bitcode files. In that case, the linker has to
+// convert bitcode files into the native format so that we can create
+// a COFF file that contains native code. This file provides that
+// functionality.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_COFF_LTO_H
+#define LLD_COFF_LTO_H
+
+#include "lld/Common/LLVM.h"
+#include "llvm/ADT/SmallString.h"
+#include <memory>
+#include <vector>
+
+namespace llvm {
+namespace lto {
+class LTO;
+}
+}
+
+namespace lld {
+namespace coff {
+
+class BitcodeFile;
+class InputFile;
+
+class BitcodeCompiler {
+public:
+  BitcodeCompiler();
+  ~BitcodeCompiler();
+
+  void add(BitcodeFile &F);
+  std::vector<StringRef> compile();
+
+private:
+  std::unique_ptr<llvm::lto::LTO> LTOObj;
+  std::vector<SmallString<0>> Buff;
+  std::vector<std::unique_ptr<MemoryBuffer>> Files;
+};
+}
+}
+
+#endif

external/llvm-project/lld/COFF/MapFile.cpp

@@ -0,0 +1,125 @@
+//===- MapFile.cpp --------------------------------------------------------===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the /lldmap option. It shows lists in order and
+// hierarchically the output sections, input sections, input files and
+// symbol:
+//
+//   Address  Size     Align Out     File    Symbol
+//   00201000 00000015     4 .text
+//   00201000 0000000e     4         test.o:(.text)
+//   0020100e 00000000     0                 local
+//   00201005 00000000     0                 f(int)
+//
+//===----------------------------------------------------------------------===//
+
+#include "MapFile.h"
+#include "SymbolTable.h"
+#include "Symbols.h"
+#include "Writer.h"
+
+#include "lld/Common/ErrorHandler.h"
+#include "llvm/Support/Parallel.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+using namespace llvm::object;
+
+using namespace lld;
+using namespace lld::coff;
+
+typedef DenseMap<const SectionChunk *, SmallVector<DefinedRegular *, 4>>
+    SymbolMapTy;
+
+// Print out the first three columns of a line.
+static void writeHeader(raw_ostream &OS, uint64_t Addr, uint64_t Size,
+                        uint64_t Align) {
+  OS << format("%08llx %08llx %5lld ", Addr, Size, Align);
+}
+
+static std::string indent(int Depth) { return std::string(Depth * 8, ' '); }
+
+// Returns a list of all symbols that we want to print out.
+static std::vector<DefinedRegular *> getSymbols() {
+  std::vector<DefinedRegular *> V;
+  for (ObjFile *File : ObjFile::Instances)
+    for (Symbol *B : File->getSymbols())
+      if (auto *Sym = dyn_cast_or_null<DefinedRegular>(B))
+        if (Sym && !Sym->getCOFFSymbol().isSectionDefinition())
+          V.push_back(Sym);
+  return V;
+}
+
+// Returns a map from sections to their symbols.
+static SymbolMapTy getSectionSyms(ArrayRef<DefinedRegular *> Syms) {
+  SymbolMapTy Ret;
+  for (DefinedRegular *S : Syms)
+    Ret[S->getChunk()].push_back(S);
+
+  // Sort symbols by address.
+  for (auto &It : Ret) {
+    SmallVectorImpl<DefinedRegular *> &V = It.second;
+    std::sort(V.begin(), V.end(), [](DefinedRegular *A, DefinedRegular *B) {
+      return A->getRVA() < B->getRVA();
+    });
+  }
+  return Ret;
+}
+
+// Construct a map from symbols to their stringified representations.
+static DenseMap<DefinedRegular *, std::string>
+getSymbolStrings(ArrayRef<DefinedRegular *> Syms) {
+  std::vector<std::string> Str(Syms.size());
+  for_each_n(parallel::par, (size_t)0, Syms.size(), [&](size_t I) {
+    raw_string_ostream OS(Str[I]);
+    writeHeader(OS, Syms[I]->getRVA(), 0, 0);
+    OS << indent(2) << toString(*Syms[I]);
+  });
+
+  DenseMap<DefinedRegular *, std::string> Ret;
+  for (size_t I = 0, E = Syms.size(); I < E; ++I)
+    Ret[Syms[I]] = std::move(Str[I]);
+  return Ret;
+}
+
+void coff::writeMapFile(ArrayRef<OutputSection *> OutputSections) {
+  if (Config->MapFile.empty())
+    return;
+
+  std::error_code EC;
+  raw_fd_ostream OS(Config->MapFile, EC, sys::fs::F_None);
+  if (EC)
+    fatal("cannot open " + Config->MapFile + ": " + EC.message());
+
+  // Collect symbol info that we want to print out.
+  std::vector<DefinedRegular *> Syms = getSymbols();
+  SymbolMapTy SectionSyms = getSectionSyms(Syms);
+  DenseMap<DefinedRegular *, std::string> SymStr = getSymbolStrings(Syms);
+
+  // Print out the header line.
+  OS << "Address  Size     Align Out     In      Symbol\n";
+
+  // Print out file contents.
+  for (OutputSection *Sec : OutputSections) {
+    writeHeader(OS, Sec->getRVA(), Sec->getVirtualSize(), /*Align=*/PageSize);
+    OS << Sec->getName() << '\n';
+
+    for (Chunk *C : Sec->getChunks()) {
+      auto *SC = dyn_cast<SectionChunk>(C);
+      if (!SC)
+        continue;
+
+      writeHeader(OS, SC->getRVA(), SC->getSize(), SC->Alignment);
+      OS << indent(1) << SC->File->getName() << ":(" << SC->getSectionName()
+         << ")\n";
+      for (DefinedRegular *Sym : SectionSyms[SC])
+        OS << SymStr[Sym] << '\n';
+    }
+  }
+}