From bbd9d610fe62f1049ebbd810863ad2a345cc9f7e Mon Sep 17 00:00:00 2001
From: Alexander Shaposhnikov <alexshap@fb.com>
Date: Thu, 15 Oct 2020 03:51:56 -0700
Subject: [PATCH] Add first bits to cross-compile the runtime for OSX

Summary: Add first bits to cross-compile the runtime for OSX.

(cherry picked from FBD24330977)
---
 bolt/runtime/CMakeLists.txt | 13 +++++++++++++
 bolt/runtime/common.h       |  6 ++++++
 bolt/runtime/hugify.cpp     |  4 ++++
 bolt/runtime/instr.cpp      | 10 ++++++++++
 4 files changed, 33 insertions(+)

diff --git a/bolt/runtime/CMakeLists.txt b/bolt/runtime/CMakeLists.txt
index a8786c8243a8..05eb0f057ba4 100644
--- a/bolt/runtime/CMakeLists.txt
+++ b/bolt/runtime/CMakeLists.txt
@@ -30,3 +30,16 @@ target_include_directories(bolt_rt_hugify PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
 install(TARGETS bolt_rt_instr DESTINATION lib)
 install(TARGETS bolt_rt_hugify DESTINATION lib)
 
+if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+  add_library(bolt_rt_instr_osx STATIC
+    instr.cpp
+    ${CMAKE_CURRENT_BINARY_DIR}/config.h
+  )
+  target_include_directories(bolt_rt_instr_osx PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
+  target_compile_options(bolt_rt_instr_osx PRIVATE
+    -target x86_64-apple-darwin19.6.0
+    -ffreestanding
+    -fno-exceptions
+    -fno-rtti)
+  install(TARGETS bolt_rt_instr_osx DESTINATION lib)
+endif()
diff --git a/bolt/runtime/common.h b/bolt/runtime/common.h
index d6f240469739..5298ebaa5f48 100644
--- a/bolt/runtime/common.h
+++ b/bolt/runtime/common.h
@@ -1,5 +1,7 @@
+#if !defined(__APPLE__)
 #include <cstddef>
 #include <cstdint>
+#endif
 
 #include "config.h"
 #ifdef HAVE_ELF_H
@@ -44,6 +46,8 @@
   "pop %%rbx\n"                                                                \
   "pop %%rax\n"
 
+#if !defined(__APPLE__)
+
 // Anonymous namespace covering everything but our library entry point
 namespace {
 
@@ -327,3 +331,5 @@ inline uint64_t alignTo(uint64_t Value, uint64_t Align) {
   return (Value + Align - 1) / Align * Align;
 }
 } // anonymous namespace
+
+#endif
diff --git a/bolt/runtime/hugify.cpp b/bolt/runtime/hugify.cpp
index 0a770a144d80..3d384fadfea2 100644
--- a/bolt/runtime/hugify.cpp
+++ b/bolt/runtime/hugify.cpp
@@ -9,6 +9,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if !defined(__APPLE__)
+
 #include "common.h"
 #include <sys/mman.h>
 
@@ -172,3 +174,5 @@ extern "C" __attribute((naked)) void __bolt_hugify_self() {
                        "jmp *__bolt_hugify_init_ptr(%%rip)\n"
                        :::);
 }
+
+#endif
diff --git a/bolt/runtime/instr.cpp b/bolt/runtime/instr.cpp
index c1401bcf0a25..e0401b8d572b 100644
--- a/bolt/runtime/instr.cpp
+++ b/bolt/runtime/instr.cpp
@@ -57,6 +57,8 @@
   {}
 #endif
 
+#if !defined(__APPLE__)
+
 // Main counters inserted by instrumentation, incremented during runtime when
 // points of interest (locations) in the program are reached. Those are direct
 // calls and direct and indirect branches (local ones). There are also counters
@@ -1460,3 +1462,11 @@ extern "C" void __bolt_instr_fini() {
     __bolt_instr_data_dump();
   DEBUG(report("Finished.\n"));
 }
+
+#else
+
+// On OSX/iOS the final symbol name of an extern "C" function/variable contains
+// one extra leading underscore: _bolt_instr_setup -> __bolt_instr_setup.
+extern "C" __attribute((section("__TEXT,__setup"))) void _bolt_instr_setup() {}
+
+#endif