[gold] Remove an external dependency to GNU binutils' header file

[ruiu]

Summary

This patch adds a header file that defines the same data types and function declarations as the binutils' "plugin-api.h" so that we can build the gold LTO plugin without binutils source code.

Since we no longer directly include a binutil's file, the documentation section that says the reuslting LLVMgold.so has to be licensed under GPLv3 has been removed.

[MaskRay]

I haven't checked but for ninja check-llvm-tools-gold, we still hope that the tests are disabled if the system does not provide gold. There may need a toggle for the tests.

[pcc]

llvm/tools/gold/gold-plugin.cpp

44–52

Can we remove this stuff now?

[ruiu]

llvm/tools/gold/gold-plugin.cpp

44–52

I believe so, but I'll do that in another patch.

[MaskRay]

It's better to move LLVM_BINUTILS_INCDIR removal for test directories into another patch. This change may expose some failures.

[ruiu]

Does it? What is your test command?

[ruiu]

I'm not sure if my credential is still valid. Do you mind if I ask you to submit this for me?

[tstellar]

What is the motivation for this change? I really don't like bundling external headers like this, because it can lead to subtle hard to catch bugs. It also makes it harder to distribute LLVM on operating systems with different versions of binutils.

Even if this change is accepted, we would need to have an attorney review whether or not this changes the license for LLVMgold.so before it can be committed.

[ruiu]

The motivation of doing this is to be able to build LLVMgold.so without binutils' source files and make it clear that LLVMgold.so does not include any GPL code.

The header file defines the public interface between linker plugins and compilers (and other tools such as ar which has to read symbol table of LTO object files). New structs or constants may be added to this header, but the existing ones will never be deleted or altered in such a way that that breaks compatibility. So, the declarations in this file aren't different from other structs and types that are defined the same as they are in GNU systems. We already have lots of such structs and types in llvm/include, no?

[tstellar]

In D125624#3552238, @ruiu wrote:

The motivation of doing this is to be able to build LLVMgold.so without binutils' source files and make it clear that LLVMgold.so does not include any GPL code.

OK, as I mentioned. I think we need an attorney to review this change and confirm that it actually accomplishes this goal.

The header file defines the public interface between linker plugins and compilers (and other tools such as ar which has to read symbol table of LTO object files). New structs or constants may be added to this header, but the existing ones will never be deleted or altered in such a way that that breaks compatibility. So, the declarations in this file aren't different from other structs and types that are defined the same as they are in GNU systems. We already have lots of such structs and types in llvm/include, no?

So what happens if LLVMgold.so uses one of the new structs or constants and then is built and run on system where binutils is old enough to not have these new structs and constants?

[ruiu]

So what happens if LLVMgold.so uses one of the new structs or constants and then is built and run on system where binutils is old enough to not have these new structs and constants?

The same thing can happen with GCC and binutils. Imagine that you install a newer version of GCC binary to your system and use it with an older version of binutils ld which doesn't know anything about new structs and constants. The plugin should still work, as changes to this file must be made in such a way that that don't break ABI. The whole point of this interface is decoupling compiler versions from linker versions. So it's backward compatible.

[khchen]

IMO, maybe we could keep the DLLVM_BINUTILS_INCDIR option support but default is using the Plugin.h?

[ruiu]

In D125624#3552284, @khchen wrote:

IMO, maybe we could keep the DLLVM_BINUTILS_INCDIR option support but default is using the Plugin.h?

We can, but I wonder what is the motivation of doing it.

[ruiu]

OK, as I mentioned. I think we need an attorney to review this change and confirm that it actually accomplishes this goal.

Can you add an attorney as a reviewer of this change so that we can proceed?

[tstellar]

In D125624#3552463, @ruiu wrote:

OK, as I mentioned. I think we need an attorney to review this change and confirm that it actually accomplishes this goal.

Can you add an attorney as a reviewer of this change so that we can proceed?

Yes, I've notified @tonic and she will reach out to the attorney.

[ruiu]

In D125624#3552770, @tstellar wrote:

In D125624#3552463, @ruiu wrote:

OK, as I mentioned. I think we need an attorney to review this change and confirm that it actually accomplishes this goal.

Can you add an attorney as a reviewer of this change so that we can proceed?

Yes, I've notified @tonic and she will reach out to the attorney.

@tstellar @tonic Did you guys get any response from the attorney?

[tstellar]

In D125624#3614298, @ruiu wrote:

In D125624#3552770, @tstellar wrote:

In D125624#3552463, @ruiu wrote:

OK, as I mentioned. I think we need an attorney to review this change and confirm that it actually accomplishes this goal.

Can you add an attorney as a reviewer of this change so that we can proceed?

Yes, I've notified @tonic and she will reach out to the attorney.

@tstellar @tonic Did you guys get any response from the attorney?

Yes, the header file will still be GPLv3 licensed even if it's copied into the LLVM tree, so even if we were to do this change, LLVMgold would still be GPLv3.

clang/CMakeLists.txt

if(APPLE)
       # will be scrubbed from the environment of any base system commands. This
       # includes /bin/sh, which ninja uses when executing build commands. To
       # work around the envar being filtered away we pass it in as a CMake
       # variable, and have LLVM's CMake append the envar to the archiver calls.
       set(LTO_LIBRARY -DDARWIN_LTO_LIBRARY=${LLVM_SHLIB_OUTPUT_INTDIR}/libLTO.dylib
         -DDYLD_LIBRARY_PATH=${LLVM_LIBRARY_OUTPUT_INTDIR})
     elseif(NOT WIN32)
       add_dependencies(clang-bootstrap-deps llvm-ar llvm-ranlib)
-      if(NOT BOOTSTRAP_LLVM_ENABLE_LLD AND LLVM_BINUTILS_INCDIR)
+      if(NOT BOOTSTRAP_LLVM_ENABLE_LLD)
         add_dependencies(clang-bootstrap-deps LLVMgold)
       endif()
       set(${CLANG_STAGE}_AR -DCMAKE_AR=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-ar)
       set(${CLANG_STAGE}_RANLIB -DCMAKE_RANLIB=${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-ranlib)
     endif()
   endif()
 
   if(CLANG_BOOTSTRAP_EXTRA_DEPS)
set(_BOOTSTRAP_DEFAULT_PASSTHROUGH
     LLVM_VERSION_MAJOR
     LLVM_VERSION_MINOR
     LLVM_VERSION_PATCH
     CLANG_VERSION_MAJOR
     CLANG_VERSION_MINOR
     CLANG_VERSION_PATCHLEVEL
     CLANG_VENDOR
     LLVM_VERSION_SUFFIX
-    LLVM_BINUTILS_INCDIR
     CLANG_REPOSITORY_STRING
     CMAKE_C_COMPILER_LAUNCHER
     CMAKE_CXX_COMPILER_LAUNCHER
     CMAKE_MAKE_PROGRAM
     CMAKE_OSX_ARCHITECTURES
     CMAKE_BUILD_TYPE
     LLVM_ENABLE_PROJECTS
     LLVM_ENABLE_RUNTIMES)

clang/docs/ThinLTO.rst

 threads in parallel, passing the resulting native object files back to the
 linker for the final native link.  As such, the usage model is the same as
 non-LTO.
 
 With gold, if you see an error during the link of the form:
 
 .. code-block:: console
 
-  /usr/bin/ld: error: /path/to/clang/bin/../lib/LLVMgold.so: could not load plugin library: /path/to/clang/bin/../lib/LLVMgold.so: cannot open shared object file: No such file or directory
+  /usr/bin/ld: fatal error: cannot use --plugin: /usr/bin/ld was compiled without plugin support
 
-Then either gold was not configured with plugins enabled, or clang
-was not built with ``-DLLVM_BINUTILS_INCDIR`` set properly. See
-the instructions for the
+Then gold was not configured with plugins enabled. See the instructions for the
 `LLVM gold plugin <https://llvm.org/docs/GoldPlugin.html#how-to-build-it>`_.
 
 Controlling Backend Parallelism
 -------------------------------
 .. _parallelism:
 
 By default, the ThinLTO link step will launch as many
 threads in parallel as there are cores. If the number of

compiler-rt/test/cfi/CMakeLists.txt

 endif()
 
 if(NOT COMPILER_RT_STANDALONE_BUILD)
   list(APPEND CFI_TEST_DEPS
     opt
     sanstats
   )
   if(LLVM_ENABLE_PIC)
-    if(LLVM_BINUTILS_INCDIR)
-      list(APPEND CFI_TEST_DEPS
-        LLVMgold
-      )
-    endif()
+    list(APPEND CFI_TEST_DEPS LLVMgold)
     if(APPLE)
       list(APPEND CFI_TEST_DEPS
         LTO
       )
     endif()
   endif()
   if(NOT APPLE AND COMPILER_RT_HAS_LLD AND TARGET lld)
     list(APPEND CFI_TEST_DEPS

compiler-rt/test/safestack/CMakeLists.txt

 set(SAFESTACK_LIT_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 set(SAFESTACK_LIT_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
 
 set(SAFESTACK_TEST_DEPS ${SANITIZER_COMMON_LIT_TEST_DEPS})
 if(NOT COMPILER_RT_STANDALONE_BUILD)
   list(APPEND SAFESTACK_TEST_DEPS safestack)
 
   # Some tests require LTO, so add a dependency on the relevant LTO plugin.
   if(LLVM_ENABLE_PIC)
-    if(LLVM_BINUTILS_INCDIR)
-      list(APPEND SAFESTACK_TEST_DEPS
-        LLVMgold
-      )
+    list(APPEND SAFESTACK_TEST_DEPS LLVMgold)
     endif()
     if(APPLE)
       list(APPEND SAFESTACK_TEST_DEPS
         LTO
       )
     endif()
   endif()
 endif()

llvm/cmake/config-ix.cmake

if(GO_CONFTEST STREQUAL "0")
       message(STATUS "Go bindings enabled.")
     else()
       message(STATUS "Go bindings disabled, need at least Go 1.2.")
     endif()
   endif()
 endif()
 
 find_program(GOLD_EXECUTABLE NAMES ${LLVM_DEFAULT_TARGET_TRIPLE}-ld.gold ld.gold ${LLVM_DEFAULT_TARGET_TRIPLE}-ld ld DOC "The gold linker")
-set(LLVM_BINUTILS_INCDIR "" CACHE PATH
-    "PATH to binutils/include containing plugin-api.h for gold plugin.")
 
 if(CMAKE_GENERATOR MATCHES "Ninja")
   execute_process(COMMAND ${CMAKE_MAKE_PROGRAM} --version
     OUTPUT_VARIABLE NINJA_VERSION
     OUTPUT_STRIP_TRAILING_WHITESPACE)
   set(NINJA_VERSION ${NINJA_VERSION} CACHE STRING "Ninja version number" FORCE)
   message(STATUS "Ninja version: ${NINJA_VERSION}")
 endif()

llvm/docs/GoldPlugin.rst

* Download, configure and build gold with plugin support:
   Once you're ready to switch to using gold, backup your existing
   ``/usr/bin/ld`` then replace it with ``ld-new``. Alternatively, install
   in ``/usr/bin/ld.gold`` and use ``-fuse-ld=gold`` as described earlier.
 
   Optionally, add ``--enable-gold=default`` to the above configure invocation
   to automatically install the newly built gold as the default linker with
   ``make install``.
 
-* Build the LLVMgold plugin. Run CMake with
-  ``-DLLVM_BINUTILS_INCDIR=/path/to/binutils/include``.  The correct include
-  path will contain the file ``plugin-api.h``.
-
 Usage
 =====
 
 You should produce bitcode files from ``clang`` with the option
 ``-flto``. This flag will also cause ``clang`` to look for the gold plugin in
 the ``lib`` directory under its prefix and pass the ``-plugin`` option to
 ``ld``. It will not look for an alternate linker without ``-fuse-ld=gold``,
 which is why you otherwise need gold to be the installed system linker in

 * Configure and build the project as usual:
 
   .. code-block:: bash
 
      % ./configure && make && make check
 
 The environment variable settings may work for non-autotooled projects too,
 but you may need to set the ``LD`` environment variable as well.
-
-Licensing
-=========
-
-Gold is licensed under the GPLv3. LLVMgold uses the interface file
-``plugin-api.h`` from gold which means that the resulting ``LLVMgold.so``
-binary is also GPLv3. This can still be used to link non-GPLv3 programs
-just as much as gold could without the plugin.

llvm/include/llvm/LTO/Plugin.h

+//===-Plugin.h - LLVM LTO Plugin API -------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares data types and functions used to support LLVMgold plugin.
+// These definitions must be in sync with GNU binutils' plugin-api.h header.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LTO_PLUGIN_H
+#define LLVM_LTO_PLUGIN_H
+
+namespace llvm {
+namespace lto {
+
+enum ld_plugin_status {
+  LDPS_OK,
+  LDPS_NO_SYMS,
+  LDPS_BAD_HANDLE,
+  LDPS_ERR,
+};
+
+enum ld_plugin_api_version {
+  LD_PLUGIN_API_VERSION = 1,
+};
+
+enum ld_plugin_output_file_type {
+  LDPO_REL,
+  LDPO_EXEC,
+  LDPO_DYN,
+  LDPO_PIE,
+};
+
+struct ld_plugin_input_file {
+  const char *name;
+  int fd;
+  uint64_t offset;
+  uint64_t filesize;
+  void *handle;
+};
+
+struct ld_plugin_symbol {
+  char *name;
+  char *version;
+#if __BIG_ENDIAN__
+  char unused;
+  char section_kind;
+  char symbol_type;
+  char def;
+#else
+  char def;
+  char symbol_type;
+  char section_kind;
+  char unused;
+#endif
+  int visibility;
+  uint64_t size;
+  char *comdat_key;
+  int resolution;
+};
+
+struct ld_plugin_section {
+  const void *handle;
+  unsigned int shndx;
+};
+
+enum ld_plugin_symbol_kind {
+  LDPK_DEF,
+  LDPK_WEAKDEF,
+  LDPK_UNDEF,
+  LDPK_WEAKUNDEF,
+  LDPK_COMMON,
+};
+
+enum ld_plugin_symbol_visibility {
+  LDPV_DEFAULT,
+  LDPV_PROTECTED,
+  LDPV_INTERNAL,
+  LDPV_HIDDEN,
+};
+
+enum ld_plugin_symbol_type {
+  LDST_UNKNOWN,
+  LDST_FUNCTION,
+  LDST_VARIABLE,
+};
+
+enum ld_plugin_symbol_section_kind {
+  LDSSK_DEFAULT,
+  LDSSK_BSS,
+};
+
+enum ld_plugin_symbol_resolution {
+  LDPR_UNKNOWN,
+  LDPR_UNDEF,
+  LDPR_PREVAILING_DEF,
+  LDPR_PREVAILING_DEF_IRONLY,
+  LDPR_PREEMPTED_REG,
+  LDPR_PREEMPTED_IR,
+  LDPR_RESOLVED_IR,
+  LDPR_RESOLVED_EXEC,
+  LDPR_RESOLVED_DYN,
+  LDPR_PREVAILING_DEF_IRONLY_EXP,
+};
+
+typedef ld_plugin_status (*ld_plugin_claim_file_handler)(
+    const ld_plugin_input_file *file, int *claimed);
+
+typedef ld_plugin_status (*ld_plugin_all_symbols_read_handler)();
+
+typedef ld_plugin_status (*ld_plugin_cleanup_handler)();
+
+typedef ld_plugin_status (*ld_plugin_register_claim_file)(
+    ld_plugin_claim_file_handler handler);
+
+typedef ld_plugin_status (*ld_plugin_register_all_symbols_read)(
+    ld_plugin_all_symbols_read_handler handler);
+
+typedef ld_plugin_status (*ld_plugin_register_cleanup)(
+    ld_plugin_cleanup_handler handler);
+
+typedef ld_plugin_status (*ld_plugin_add_symbols)(void *handle, int nsyms,
+                                                  const ld_plugin_symbol *syms);
+
+typedef ld_plugin_status (*ld_plugin_get_input_file)(
+    const void *handle, ld_plugin_input_file *file);
+
+typedef ld_plugin_status (*ld_plugin_get_view)(const void *handle,
+                                               const void **viewp);
+
+typedef ld_plugin_status (*ld_plugin_release_input_file)(const void *handle);
+
+typedef ld_plugin_status (*ld_plugin_get_symbols)(const void *handle, int nsyms,
+                                                  ld_plugin_symbol *syms);
+
+typedef ld_plugin_status (*ld_plugin_add_input_file)(const char *pathname);
+
+typedef ld_plugin_status (*ld_plugin_add_input_library)(const char *libname);
+
+typedef ld_plugin_status (*ld_plugin_set_extra_library_path)(const char *path);
+
+typedef ld_plugin_status (*ld_plugin_message)(int level, const char *format,
+                                              ...);
+
+typedef ld_plugin_status (*ld_plugin_get_input_section_count)(
+    const void *handle, unsigned int *count);
+
+typedef ld_plugin_status (*ld_plugin_get_input_section_type)(
+    const ld_plugin_section section, unsigned int *type);
+
+typedef ld_plugin_status (*ld_plugin_get_input_section_name)(
+    const ld_plugin_section section, char **section_name_ptr);
+
+typedef ld_plugin_status (*ld_plugin_get_input_section_contents)(
+    const ld_plugin_section section, const unsigned char **section_contents,
+    size_t *len);
+
+typedef ld_plugin_status (*ld_plugin_update_section_order)(
+    const ld_plugin_section *section_list, unsigned int num_sections);
+
+typedef ld_plugin_status (*ld_plugin_allow_section_ordering)();
+
+typedef ld_plugin_status (*ld_plugin_allow_unique_segment_for_sections)();
+
+typedef ld_plugin_status (*ld_plugin_unique_segment_for_sections)(
+    const char *segment_name, uint64_t segment_flags,
+    uint64_t segment_alignment, const ld_plugin_section *section_list,
+    unsigned int num_sections);
+
+typedef ld_plugin_status (*ld_plugin_get_input_section_alignment)(
+    const ld_plugin_section section, unsigned int *addralign);
+
+typedef ld_plugin_status (*ld_plugin_get_input_section_size)(
+    const ld_plugin_section section, uint64_t *secsize);
+
+typedef ld_plugin_status (*ld_plugin_new_input_handler)(
+    const ld_plugin_input_file *file);
+
+typedef ld_plugin_status (*ld_plugin_register_new_input)(
+    ld_plugin_new_input_handler handler);
+
+typedef ld_plugin_status (*ld_plugin_get_wrap_symbols)(
+    uint64_t *num_symbols, const char ***wrap_symbol_list);
+
+enum ld_plugin_level {
+  LDPL_INFO,
+  LDPL_WARNING,
+  LDPL_ERROR,
+  LDPL_FATAL,
+};
+
+enum ld_plugin_tag {
+  LDPT_NULL,
+  LDPT_API_VERSION,
+  LDPT_GOLD_VERSION,
+  LDPT_LINKER_OUTPUT,
+  LDPT_OPTION,
+  LDPT_REGISTER_CLAIM_FILE_HOOK,
+  LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK,
+  LDPT_REGISTER_CLEANUP_HOOK,
+  LDPT_ADD_SYMBOLS,
+  LDPT_GET_SYMBOLS,
+  LDPT_ADD_INPUT_FILE,
+  LDPT_MESSAGE,
+  LDPT_GET_INPUT_FILE,
+  LDPT_RELEASE_INPUT_FILE,
+  LDPT_ADD_INPUT_LIBRARY,
+  LDPT_OUTPUT_NAME,
+  LDPT_SET_EXTRA_LIBRARY_PATH,
+  LDPT_GNU_LD_VERSION,
+  LDPT_GET_VIEW,
+  LDPT_GET_INPUT_SECTION_COUNT,
+  LDPT_GET_INPUT_SECTION_TYPE,
+  LDPT_GET_INPUT_SECTION_NAME,
+  LDPT_GET_INPUT_SECTION_CONTENTS,
+  LDPT_UPDATE_SECTION_ORDER,
+  LDPT_ALLOW_SECTION_ORDERING,
+  LDPT_GET_SYMBOLS_V2,
+  LDPT_ALLOW_UNIQUE_SEGMENT_FOR_SECTIONS,
+  LDPT_UNIQUE_SEGMENT_FOR_SECTIONS,
+  LDPT_GET_SYMBOLS_V3,
+  LDPT_GET_INPUT_SECTION_ALIGNMENT,
+  LDPT_GET_INPUT_SECTION_SIZE,
+  LDPT_REGISTER_NEW_INPUT_HOOK,
+  LDPT_GET_WRAP_SYMBOLS,
+  LDPT_ADD_SYMBOLS_V2,
+};
+
+struct ld_plugin_tv {
+  ld_plugin_tag tv_tag;
+
+  union {
+    int tv_val;
+    const char *tv_string;
+    ld_plugin_register_claim_file tv_register_claim_file;
+    ld_plugin_register_all_symbols_read tv_register_all_symbols_read;
+    ld_plugin_register_cleanup tv_register_cleanup;
+    ld_plugin_add_symbols tv_add_symbols;
+    ld_plugin_get_symbols tv_get_symbols;
+    ld_plugin_add_input_file tv_add_input_file;
+    ld_plugin_message tv_message;
+    ld_plugin_get_input_file tv_get_input_file;
+    ld_plugin_get_view tv_get_view;
+    ld_plugin_release_input_file tv_release_input_file;
+    ld_plugin_add_input_library tv_add_input_library;
+    ld_plugin_set_extra_library_path tv_set_extra_library_path;
+    ld_plugin_get_input_section_count tv_get_input_section_count;
+    ld_plugin_get_input_section_type tv_get_input_section_type;
+    ld_plugin_get_input_section_name tv_get_input_section_name;
+    ld_plugin_get_input_section_contents tv_get_input_section_contents;
+    ld_plugin_update_section_order tv_update_section_order;
+    ld_plugin_allow_section_ordering tv_allow_section_ordering;
+    ld_plugin_allow_unique_segment_for_sections
+        tv_allow_unique_segment_for_sections;
+    ld_plugin_unique_segment_for_sections tv_unique_segment_for_sections;
+    ld_plugin_get_input_section_alignment tv_get_input_section_alignment;
+    ld_plugin_get_input_section_size tv_get_input_section_size;
+    ld_plugin_register_new_input tv_register_new_input;
+    ld_plugin_get_wrap_symbols tv_get_wrap_symbols;
+  } tv_u;
+};
+
+typedef ld_plugin_status (*ld_plugin_onload)(ld_plugin_tv *tv);
+
+} // namespace lto
+} // namespace llvm
+
+#endif

llvm/tools/gold/CMakeLists.txt

 set(LLVM_EXPORTED_SYMBOL_FILE ${CMAKE_CURRENT_SOURCE_DIR}/gold.exports)
 
-if( LLVM_ENABLE_PIC AND LLVM_BINUTILS_INCDIR )
-  include_directories( ${LLVM_BINUTILS_INCDIR} )
-
+if (LLVM_ENABLE_PIC)
   set(LLVM_LINK_COMPONENTS
      ${LLVM_TARGETS_TO_BUILD}
      Linker
      LTO
      BitWriter
      IPO
      )
 
   add_llvm_library(LLVMgold MODULE
     gold-plugin.cpp
     )
 
 endif()

llvm/tools/gold/gold-plugin.cpp

 #include "llvm/Bitcode/BitcodeReader.h"
 #include "llvm/Bitcode/BitcodeWriter.h"
 #include "llvm/CodeGen/CommandFlags.h"
 #include "llvm/Config/config.h" // plugin-api.h requires HAVE_STDINT_H
 #include "llvm/Config/llvm-config.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DiagnosticPrinter.h"
 #include "llvm/LTO/LTO.h"
+#include "llvm/LTO/Plugin.h"
 #include "llvm/Object/Error.h"
 #include "llvm/Remarks/HotnessThresholdParser.h"
 #include "llvm/Support/CachePruning.h"
 #include "llvm/Support/Caching.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/Threading.h"
 #include "llvm/Support/raw_ostream.h"
 #include <list>
 #include <map>
-#include <plugin-api.h>
 #include <string>
 #include <system_error>
 #include <utility>
 #include <vector>
 
 // FIXME: remove this declaration when we stop maintaining Ubuntu Quantal and
 // Precise and Debian Wheezy (binutils 2.23 is required)
 #define LDPO_PIE 3
 
 #define LDPT_GET_SYMBOLS_V3 28
 
 // FIXME: Remove when binutils 2.31 (containing gold 1.16) is the minimum
 // required version.
 #define LDPT_GET_WRAP_SYMBOLS 32
 
 using namespace llvm;
 using namespace lto;
 
 static codegen::RegisterCodeGenFlags CodeGenFlags;
 
 // FIXME: Remove when binutils 2.31 (containing gold 1.16) is the minimum
 // required version.