Re-apply "[CMake][compiler-rt][AArch64] Avoid preprocessing LSE builtins separately"

[tambre]

Summary

aa772fc85e0f526615c78b9c3979c2be945a754c (D92530) has landed fixing relocations on Darwin.
3000c19df64f89ff319590f3a6e4d6b93d20983d (D93236) has landed working around an assembly parser bug on Darwin.
Previous quick-fix d9697c2e6b153ac7dc40a69450d9b672f71b1029 (D93198) included in this commit.

Invoking the preprocessor ourselves is fragile and would require us to replicate CMake's handling of definitions, compiler flags, etc for proper compatibility.
In my toolchain builds this notably resulted in a bunch of warnings from unused flags as my CMAKE_C_FLAGS includes CPU-specific optimization options.
Notably this part was already duplicating the logic for VISIBILITY_HIDDEN define.

Instead, symlink the files and set the proper set of defines on each.
This should also be faster as we avoid invoking the compiler multiple times.

Fixes https://llvm.org/PR48494

[thakis]

Early heads-up: We're seeing compile errors on our arm64 bots that might be due to this change: https://bugs.chromium.org/p/chromium/issues/detail?id=1159420

I'll verify locally and make a stand-alone repro. (It's possible that I'll find it's not due to this change while doing this.)

[tambre]

In D93278#2457928, @thakis wrote:

Early heads-up: We're seeing compile errors on our arm64 bots that might be due to this change: https://bugs.chromium.org/p/chromium/issues/detail?id=1159420

I'll verify locally and make a stand-alone repro. (It's possible that I'll find it's not due to this change while doing this.)

A few followup fixes have landed for Darwin:

• D93378
• D93379
• D93390

I suspect the issue you're seeing is fixed by D93378.
Previously the alignment specifier along with some other assembly directives would end up as comments with the Darwin assembly parser due to an incorrect separator being used.
See D93211 for the discussion.

[thakis]

In D93278#2457940, @tambre wrote:

In D93278#2457928, @thakis wrote:

Early heads-up: We're seeing compile errors on our arm64 bots that might be due to this change: https://bugs.chromium.org/p/chromium/issues/detail?id=1159420

I'll verify locally and make a stand-alone repro. (It's possible that I'll find it's not due to this change while doing this.)

A few followup fixes have landed for Darwin:

• D93378
• D93379
• D93390

I suspect the issue you're seeing is fixed by D93378.
Previously the alignment specifier along with some other assembly directives would end up as comments with the Darwin assembly parser due to an incorrect separator being used.
See D93211 for the discussion.

Great, thanks! I'll try again with a newer clang, but does indeed look like it should fix the problem we're seeing.

[ikudrin]

This change causes build failures in my Windows environment.

compiler-rt/lib/builtins/CMakeLists.txt

522

cmake -E create_symlink requires privilege escalation on Windows. Do you mind to fallback to just copy in that case? Something similar to what is used in AddLLVM.cmake and some other places.

compiler-rt/cmake/Modules/CompilerRTDarwinUtils.cmake

 macro(darwin_add_builtin_libraries)
   set(DARWIN_EXCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/Darwin-excludes)
 
   set(CFLAGS "-fPIC -O3 -fvisibility=hidden -DVISIBILITY_HIDDEN -Wall -fomit-frame-pointer")
   set(CMAKE_C_FLAGS "")
   set(CMAKE_CXX_FLAGS "")
   set(CMAKE_ASM_FLAGS "")
 
-  set(PROFILE_SOURCES ../profile/InstrProfiling 
+  append_string_if(COMPILER_RT_HAS_ASM_LSE " -DHAS_ASM_LSE" CFLAGS)
+
+  set(PROFILE_SOURCES ../profile/InstrProfiling
                       ../profile/InstrProfilingBuffer
                       ../profile/InstrProfilingPlatformDarwin
                       ../profile/InstrProfilingWriter
                       ../profile/InstrProfilingInternal
                       ../profile/InstrProfilingVersionVar)
   foreach (os ${ARGN})
     list_intersect(DARWIN_BUILTIN_ARCHS DARWIN_${os}_BUILTIN_ARCHS BUILTIN_SUPPORTED_ARCH)
     foreach (arch ${DARWIN_BUILTIN_ARCHS})

compiler-rt/lib/builtins/CMakeLists.txt

 set(aarch64_SOURCES
   ${GENERIC_TF_SOURCES}
   ${GENERIC_SOURCES}
   cpu_model.c
   aarch64/fp_mode.c
 )
 
 # Generate outline atomics helpers from lse.S base
-set(CUSTOM_FLAGS ${CMAKE_C_FLAGS})
-if(NOT ANDROID)
-  append_list_if(COMPILER_RT_HAS_VISIBILITY_HIDDEN_FLAG -DVISIBILITY_HIDDEN CUSTOM_FLAGS)
-endif()
-append_list_if(COMPILER_RT_HAS_ASM_LSE -DHAS_ASM_LSE CUSTOM_FLAGS)
-string(REPLACE " " "\t" CUSTOM_FLAGS "${CUSTOM_FLAGS}")
 set(OA_HELPERS_DIR "${CMAKE_CURRENT_BINARY_DIR}/outline_atomic_helpers.dir")
-file(MAKE_DIRECTORY ${OA_HELPERS_DIR})
+file(MAKE_DIRECTORY "${OA_HELPERS_DIR}")
 
 foreach(pat cas swp ldadd ldclr ldeor ldset)
   foreach(size 1 2 4 8 16)
     foreach(model 1 2 3 4)
       if(pat STREQUAL "cas" OR NOT size STREQUAL "16")
-        set(helper_asm ${OA_HELPERS_DIR}/outline_atomic_${pat}${size}_${model}.S)
+        set(helper_asm "${OA_HELPERS_DIR}/outline_atomic_${pat}${size}_${model}.S")
         add_custom_command(
           OUTPUT ${helper_asm}
-          COMMAND ${CMAKE_C_COMPILER} -E ${CUSTOM_FLAGS} -DL_${pat} -DSIZE=${size} -DMODEL=${model}
-                  ${CMAKE_CURRENT_SOURCE_DIR}/aarch64/lse.S -o ${helper_asm}
-          DEPENDS aarch64/lse.S assembly.h
+          COMMAND ${CMAKE_COMMAND} -E create_symlink "${CMAKE_CURRENT_SOURCE_DIR}/aarch64/lse.S" "${helper_asm}"
         )
-        set_source_files_properties(${helper_asm} PROPERTIES GENERATED TRUE)
-        set(aarch64_SOURCES
-          ${aarch64_SOURCES}
-          ${helper_asm}
+        set_source_files_properties("${helper_asm}"
+          PROPERTIES
+          COMPILE_DEFINITIONS "L_${pat};SIZE=${size};MODEL=${model}"
+          INCLUDE_DIRECTORIES "${CMAKE_CURRENT_SOURCE_DIR}"
         )
+        list(APPEND aarch64_SOURCES "${helper_asm}")
       endif()
     endforeach(model)
   endforeach(size)
 endforeach(pat)
 
 if (MINGW)
   set(aarch64_SOURCES
     ${aarch64_SOURCES}
else ()
   endif()
 
   set(BUILTIN_DEFS "")
 
   if(NOT ANDROID)
     append_list_if(COMPILER_RT_HAS_VISIBILITY_HIDDEN_FLAG VISIBILITY_HIDDEN BUILTIN_DEFS)
   endif()
 
+  append_list_if(COMPILER_RT_HAS_ASM_LSE HAS_ASM_LSE BUILTIN_DEFS)
+
   foreach (arch ${BUILTIN_SUPPORTED_ARCH})
     if (CAN_TARGET_${arch})
       # For ARM archs, exclude any VFP builtins if VFP is not supported
       if (${arch} MATCHES "^(arm|armhf|armv7|armv7s|armv7k|armv7m|armv7em)$")
         string(REPLACE ";" " " _TARGET_${arch}_CFLAGS "${TARGET_${arch}_CFLAGS}")
         check_compile_definition(__ARM_FP "${CMAKE_C_FLAGS} ${_TARGET_${arch}_CFLAGS}" COMPILER_RT_HAS_${arch}_VFP)
         if(NOT COMPILER_RT_HAS_${arch}_VFP)
           list(REMOVE_ITEM ${arch}_SOURCES ${arm_Thumb1_VFPv2_DP_SOURCES} ${arm_Thumb1_VFPv2_SP_SOURCES} ${arm_Thumb1_SjLj_EH_SOURCES})

compiler-rt/lib/builtins/aarch64/lse.S

 // 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
 
-#include "../assembly.h"
+#include "assembly.h"
 
 // Out-of-line LSE atomics helpers. Ported from libgcc library.
 // N = {1, 2, 4, 8}
 // M = {1, 2, 4, 8, 16}
 // ORDER = {'relax', 'acq', 'rel', 'acq_rel'}
 // Routines implemented:
 //
 //  iM __aarch64_casM_ORDER(iM expected, iM desired, iM *ptr)