[BOLT] Only link and initialize supported targets (#127509)

Bolt currently links and initializes all LLVM targets. This
substantially increases the binary size, and link time if LTO is used.

Instead, only link the targets specified by BOLT_TARGETS_TO_BUILD. We
also have to only initialize those targets, so generate a
TargetConfig.def file with the necessary information. The way the
initialization is done mirrors what llvm-exegesis does.

This reduces llvm-bolt size from 137MB to 78MB for me.

bolt/CMakeLists.txt

@@ -202,3 +202,11 @@ endif()
 
 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/include/bolt/RuntimeLibs/RuntimeLibraryVariables.inc.in
                ${CMAKE_CURRENT_BINARY_DIR}/include/bolt/RuntimeLibs/RuntimeLibraryVariables.inc @ONLY)
+
+set(BOLT_ENUM_TARGETS "")
+foreach(t ${BOLT_TARGETS_TO_BUILD})
+  set(BOLT_ENUM_TARGETS "${BOLT_ENUM_TARGETS}BOLT_TARGET(${t})\n")
+endforeach(t)
+
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/include/bolt/Core/TargetConfig.def.in
+               ${CMAKE_CURRENT_BINARY_DIR}/include/bolt/Core/TargetConfig.def @ONLY)

bolt/include/bolt/Core/TargetConfig.def.in

@@ -0,0 +1,23 @@
+//===-- TargetConfig.def.in - Information about available targets ---------===//
+//
+// 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 is configured by the build system to define the available bolt
+// targets.
+//
+// The variant of this file not ending with .in has been autogenerated by the
+// LLVM build. Do not edit!
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef BOLT_TARGET
+#  error Please define the macro BOLT_TARGET(TargetName)
+#endif
+
+@BOLT_ENUM_TARGETS@
+
+#undef BOLT_TARGET

bolt/tools/binary-analysis/CMakeLists.txt

@@ -1,5 +1,5 @@
 set(LLVM_LINK_COMPONENTS
-  ${LLVM_TARGETS_TO_BUILD}
+  ${BOLT_TARGETS_TO_BUILD}
   MC
   Object
   Support

bolt/tools/binary-analysis/binary-analysis.cpp

@@ -88,13 +88,15 @@ int main(int argc, char **argv) {
   llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
 
   // Initialize targets and assembly printers/parsers.
-  llvm::InitializeAllTargetInfos();
+#define BOLT_TARGET(target)                                                    \
-  llvm::InitializeAllTargetMCs();
+  LLVMInitialize##target##TargetInfo();                                        \
-  llvm::InitializeAllAsmParsers();
+  LLVMInitialize##target##TargetMC();                                          \
-  llvm::InitializeAllDisassemblers();
+  LLVMInitialize##target##AsmParser();                                         \
+  LLVMInitialize##target##Disassembler();                                      \
+  LLVMInitialize##target##Target();                                            \
+  LLVMInitialize##target##AsmPrinter();
 
-  llvm::InitializeAllTargets();
+#include "bolt/Core/TargetConfig.def"
-  llvm::InitializeAllAsmPrinters();
 
   ParseCommandLine(argc, argv);
 

bolt/tools/driver/CMakeLists.txt

@@ -1,5 +1,5 @@
 set(LLVM_LINK_COMPONENTS
-  ${LLVM_TARGETS_TO_BUILD}
+  ${BOLT_TARGETS_TO_BUILD}
   MC
   Object
   Support

bolt/tools/driver/llvm-bolt.cpp

@@ -183,13 +183,15 @@ int main(int argc, char **argv) {
   std::string ToolPath = llvm::sys::fs::getMainExecutable(argv[0], nullptr);
 
   // Initialize targets and assembly printers/parsers.
-  llvm::InitializeAllTargetInfos();
+#define BOLT_TARGET(target)                                                    \
-  llvm::InitializeAllTargetMCs();
+  LLVMInitialize##target##TargetInfo();                                        \
-  llvm::InitializeAllAsmParsers();
+  LLVMInitialize##target##TargetMC();                                          \
-  llvm::InitializeAllDisassemblers();
+  LLVMInitialize##target##AsmParser();                                         \
+  LLVMInitialize##target##Disassembler();                                      \
+  LLVMInitialize##target##Target();                                            \
+  LLVMInitialize##target##AsmPrinter();
 
-  llvm::InitializeAllTargets();
+#include "bolt/Core/TargetConfig.def"
-  llvm::InitializeAllAsmPrinters();
 
   ToolName = argv[0];
 

bolt/tools/heatmap/CMakeLists.txt

@@ -1,5 +1,5 @@
 set(LLVM_LINK_COMPONENTS
-  ${LLVM_TARGETS_TO_BUILD}
+  ${BOLT_TARGETS_TO_BUILD}
   MC
   Object
   Support

bolt/tools/heatmap/heatmap.cpp

@@ -76,13 +76,15 @@ int main(int argc, char **argv) {
     opts::OutputFilename = "-";
 
   // Initialize targets and assembly printers/parsers.
-  llvm::InitializeAllTargetInfos();
+#define BOLT_TARGET(target)                                                    \
-  llvm::InitializeAllTargetMCs();
+  LLVMInitialize##target##TargetInfo();                                        \
-  llvm::InitializeAllAsmParsers();
+  LLVMInitialize##target##TargetMC();                                          \
-  llvm::InitializeAllDisassemblers();
+  LLVMInitialize##target##AsmParser();                                         \
+  LLVMInitialize##target##Disassembler();                                      \
+  LLVMInitialize##target##Target();                                            \
+  LLVMInitialize##target##AsmPrinter();
 
-  llvm::InitializeAllTargets();
+#include "bolt/Core/TargetConfig.def"
-  llvm::InitializeAllAsmPrinters();
 
   ToolName = argv[0];
   std::string ToolPath = GetExecutablePath(argv[0]);

bolt/tools/llvm-bolt-fuzzer/CMakeLists.txt

@@ -1,5 +1,5 @@
 set(LLVM_LINK_COMPONENTS
-  ${LLVM_TARGETS_TO_BUILD}
+  ${BOLT_TARGETS_TO_BUILD}
   )
 
 add_llvm_fuzzer(llvm-bolt-fuzzer

bolt/tools/llvm-bolt-fuzzer/llvm-bolt-fuzzer.cpp

@@ -58,13 +58,16 @@ extern "C" int LLVMFuzzerTestOneInput(const char *Data, size_t Size) {
 
 extern "C" LLVM_ATTRIBUTE_USED int LLVMFuzzerInitialize(int *argc,
                                                         char ***argv) {
-  llvm::InitializeAllTargetInfos();
+  // Initialize targets and assembly printers/parsers.
-  llvm::InitializeAllTargetMCs();
+#define BOLT_TARGET(target)                                                    \
-  llvm::InitializeAllAsmParsers();
+  LLVMInitialize##target##TargetInfo();                                        \
-  llvm::InitializeAllDisassemblers();
+  LLVMInitialize##target##TargetMC();                                          \
+  LLVMInitialize##target##AsmParser();                                         \
+  LLVMInitialize##target##Disassembler();                                      \
+  LLVMInitialize##target##Target();                                            \
+  LLVMInitialize##target##AsmPrinter();
 
-  llvm::InitializeAllTargets();
+#include "bolt/Core/TargetConfig.def"
-  llvm::InitializeAllAsmPrinters();
 
   return 0;
 }

bolt/unittests/Core/BinaryContext.cpp

@@ -27,12 +27,15 @@ struct BinaryContextTester : public testing::TestWithParam<Triple::ArchType> {
 
 protected:
   void initalizeLLVM() {
-    llvm::InitializeAllTargetInfos();
+#define BOLT_TARGET(target)                                                    \
-    llvm::InitializeAllTargetMCs();
+  LLVMInitialize##target##TargetInfo();                                        \
-    llvm::InitializeAllAsmParsers();
+  LLVMInitialize##target##TargetMC();                                          \
-    llvm::InitializeAllDisassemblers();
+  LLVMInitialize##target##AsmParser();                                         \
-    llvm::InitializeAllTargets();
+  LLVMInitialize##target##Disassembler();                                      \
-    llvm::InitializeAllAsmPrinters();
+  LLVMInitialize##target##Target();                                            \
+  LLVMInitialize##target##AsmPrinter();
+
+#include "bolt/Core/TargetConfig.def"
   }
 
   void prepareElf() {

bolt/unittests/Core/CMakeLists.txt

@@ -2,7 +2,7 @@ set(LLVM_LINK_COMPONENTS
   DebugInfoDWARF
   Object
   MC
-  ${LLVM_TARGETS_TO_BUILD}
+  ${BOLT_TARGETS_TO_BUILD}
   )
 
 add_bolt_unittest(CoreTests

bolt/unittests/Core/MCPlusBuilder.cpp

@@ -37,12 +37,15 @@ struct MCPlusBuilderTester : public testing::TestWithParam<Triple::ArchType> {
 
 protected:
   void initalizeLLVM() {
-    llvm::InitializeAllTargetInfos();
+#define BOLT_TARGET(target)                                                    \
-    llvm::InitializeAllTargetMCs();
+  LLVMInitialize##target##TargetInfo();                                        \
-    llvm::InitializeAllAsmParsers();
+  LLVMInitialize##target##TargetMC();                                          \
-    llvm::InitializeAllDisassemblers();
+  LLVMInitialize##target##AsmParser();                                         \
-    llvm::InitializeAllTargets();
+  LLVMInitialize##target##Disassembler();                                      \
-    llvm::InitializeAllAsmPrinters();
+  LLVMInitialize##target##Target();                                            \
+  LLVMInitialize##target##AsmPrinter();
+
+#include "bolt/Core/TargetConfig.def"
   }
 
   void prepareElf() {

bolt/unittests/Core/MemoryMaps.cpp

@@ -38,12 +38,15 @@ struct MemoryMapsTester : public testing::TestWithParam<Triple::ArchType> {
 
 protected:
   void initalizeLLVM() {
-    llvm::InitializeAllTargetInfos();
+#define BOLT_TARGET(target)                                                    \
-    llvm::InitializeAllTargetMCs();
+  LLVMInitialize##target##TargetInfo();                                        \
-    llvm::InitializeAllAsmParsers();
+  LLVMInitialize##target##TargetMC();                                          \
-    llvm::InitializeAllDisassemblers();
+  LLVMInitialize##target##AsmParser();                                         \
-    llvm::InitializeAllTargets();
+  LLVMInitialize##target##Disassembler();                                      \
-    llvm::InitializeAllAsmPrinters();
+  LLVMInitialize##target##Target();                                            \
+  LLVMInitialize##target##AsmPrinter();
+
+#include "bolt/Core/TargetConfig.def"
   }
 
   void prepareElf() {