From 86800abc8135e7860be46239d598f0a76132ce48 Mon Sep 17 00:00:00 2001
From: Facebook Github Bot <facebook-github-bot@users.noreply.github.com>
Date: Wed, 24 Jul 2019 11:05:08 -0700
Subject: [PATCH] [BOLT][PR] Target compilation based on LLVM CMake
 configuration

Summary:

Minimalist implementation of target configurable compilation.

Fixes https://github.com/facebookincubator/BOLT/issues/59
Pull Request resolved: https://github.com/facebookincubator/BOLT/pull/60
GitHub Author: Pierre RAMOIN <pierre.ramoin@amadeus.com>

(cherry picked from FBD16461879)
---
 bolt/src/CMakeLists.txt      | 22 ++++++++++++++++++++--
 bolt/src/RewriteInstance.cpp | 17 ++++++++++-------
 2 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/bolt/src/CMakeLists.txt b/bolt/src/CMakeLists.txt
index 6b60171355f7..d265e98a966d 100644
--- a/bolt/src/CMakeLists.txt
+++ b/bolt/src/CMakeLists.txt
@@ -48,8 +48,6 @@ add_public_gen_version_target(GenBoltRevision)
 set(LLVM_LINK_COMPONENTS
   ${LLVM_TARGETS_TO_BUILD}
   BOLTPasses
-  BOLTTargetAArch64
-  BOLTTargetX86
   CodeGen
   Core
   DebugInfoDWARF
@@ -61,6 +59,18 @@ set(LLVM_LINK_COMPONENTS
   Support
   )
 
+string(FIND "${LLVM_TARGETS_TO_BUILD}" "AArch64" POSITION)
+if (NOT ${POSITION} EQUAL -1)
+  list(APPEND LLVM_LINK_COMPONENTS BOLTTargetAArch64)
+  set(BOLT_AArcb64 On)
+endif()
+
+string(FIND "${LLVM_TARGETS_TO_BUILD}" "X86" POSITION)
+if (NOT ${POSITION} EQUAL -1)
+  list(APPEND LLVM_LINK_COMPONENTS BOLTTargetX86)
+  set(BOLT_X64 On)
+endif()
+
 add_llvm_tool(llvm-bolt
   llvm-bolt.cpp
   BinaryBasicBlock.cpp
@@ -93,6 +103,14 @@ add_llvm_tool(llvm-bolt
   intrinsics_gen
   )
 
+if (DEFINED BOLT_AArcb64)
+  target_compile_definitions(llvm-bolt PRIVATE AARCH64_AVAILABLE)
+endif()
+
+if (DEFINED BOLT_X64)
+  target_compile_definitions(llvm-bolt PRIVATE X86_AVAILABLE)
+endif()
+
 add_llvm_tool_symlink(perf2bolt llvm-bolt)
 add_llvm_tool_symlink(llvm-boltdiff llvm-bolt)
 add_llvm_tool_symlink(llvm-bolt-heatmap llvm-bolt)
diff --git a/bolt/src/RewriteInstance.cpp b/bolt/src/RewriteInstance.cpp
index 6bdceca1c9f4..58c6e20486b6 100644
--- a/bolt/src/RewriteInstance.cpp
+++ b/bolt/src/RewriteInstance.cpp
@@ -535,15 +535,18 @@ namespace {
 MCPlusBuilder *createMCPlusBuilder(const Triple::ArchType Arch,
     const MCInstrAnalysis *Analysis, const MCInstrInfo *Info,
     const MCRegisterInfo *RegInfo) {
-  if (Arch == Triple::x86_64) {
+#ifdef X86_AVAILABLE
+  if (Arch == Triple::x86_64)
     return createX86MCPlusBuilder(Analysis, Info, RegInfo);
-  } else if (Arch == Triple::aarch64) {
-    return createAArch64MCPlusBuilder(Analysis, Info, RegInfo);
-  } else {
-    llvm_unreachable("architecture unsupport by MCPlusBuilder");
-  }
-}
+#endif
 
+#ifdef AARCH64_AVAILABLE
+  if (Arch == Triple::aarch64)
+    return createAArch64MCPlusBuilder(Analysis, Info, RegInfo);
+#endif
+
+    llvm_unreachable("architecture unsupport by MCPlusBuilder");
+}
 }
 
 constexpr const char *RewriteInstance::SectionsToOverwrite[];