[PATCH] D87487: [compiler-rt][cmake] Attempt to fix build race condition

[Mark Searles via Phabricator via llvm-commits]

msearles created this revision.
msearles added reviewers: ro, eugenis.
Herald added subscribers: Sanitizers, mgorny, dberris.
Herald added a project: Sanitizers.
msearles requested review of this revision.



  Fix for https://bugs.llvm.org/show_bug.cgi?id=26054
  
  There was code which purported to work around a bug in cmake version
  2. This involved creating a dummy.cpp file which had dependencies on
  the '.vers' script.
  
  Now that cmake version 3.13.4 is the minimum version of cmake this
  work-around is removed and a straight forward dependency on the PHONY
  target clang_rt.asan-dynamic-${arch}-version-list is introduced.
  
  This appears to work with both GNUmake and ninja as targets.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D87487

Files:
  compiler-rt/lib/asan/CMakeLists.txt


Index: compiler-rt/lib/asan/CMakeLists.txt
===================================================================
--- compiler-rt/lib/asan/CMakeLists.txt
+++ compiler-rt/lib/asan/CMakeLists.txt
@@ -149,13 +149,6 @@
     DEFS ${ASAN_COMMON_DEFINITIONS}
     DEPS ${ASAN_DEPS})
 
-  file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/dummy.cpp "")
-  add_compiler_rt_object_libraries(RTAsan_dynamic_version_script_dummy
-    ARCHS ${ASAN_SUPPORTED_ARCH}
-    SOURCES ${CMAKE_CURRENT_BINARY_DIR}/dummy.cpp
-    CFLAGS ${ASAN_DYNAMIC_CFLAGS}
-    DEFS ${ASAN_DYNAMIC_DEFINITIONS}
-    DEPS ${ASAN_DEPS})
 endif()
 
 # Build ASan runtimes shipped with Clang.
@@ -225,6 +218,9 @@
 
   foreach(arch ${ASAN_SUPPORTED_ARCH})
     if (COMPILER_RT_HAS_VERSION_SCRIPT)
+      # adds a custom target clang_rt.asan-dynamic-${arch}-version-list
+      # which depends on vers = ${CMAKE_CURRENT_BINARY_DIR}/clang_rt.asan-dynamic-${arch}.vers
+      # and runs python to generate it.
       add_sanitizer_rt_version_list(clang_rt.asan-dynamic-${arch}
                                     LIBS clang_rt.asan-${arch} clang_rt.asan_cxx-${arch}
                                     EXTRA asan.syms.extra)
@@ -235,10 +231,6 @@
       if (COMPILER_RT_HAS_GNU_VERSION_SCRIPT_COMPAT)
           list(APPEND VERSION_SCRIPT_FLAG -Wl,-z,gnu-version-script-compat)
       endif()
-      set_property(SOURCE
-        ${CMAKE_CURRENT_BINARY_DIR}/dummy.cpp
-        APPEND PROPERTY
-        OBJECT_DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/clang_rt.asan-dynamic-${arch}.vers)
     else()
       set(VERSION_SCRIPT_FLAG)
     endif()
@@ -264,12 +256,6 @@
       ARCHS ${arch}
       OBJECT_LIBS ${ASAN_COMMON_RUNTIME_OBJECT_LIBS}
               RTAsan_dynamic
-              # The only purpose of RTAsan_dynamic_version_script_dummy is to
-              # carry a dependency of the shared runtime on the version script.
-              # Replacing it with a straightforward
-              # add_dependencies(clang_rt.asan-dynamic-${arch} clang_rt.asan-dynamic-${arch}-version-list)
-              # generates an order-only dependency in ninja.
-              RTAsan_dynamic_version_script_dummy
               RTUbsan_cxx
               ${ASAN_DYNAMIC_WEAK_INTERCEPTION}
       CFLAGS ${ASAN_DYNAMIC_CFLAGS}
@@ -278,6 +264,7 @@
       LINK_LIBS ${ASAN_DYNAMIC_LIBS}
       DEFS ${ASAN_DYNAMIC_DEFINITIONS}
       PARENT_TARGET asan)
+    add_dependencies(clang_rt.asan-dynamic-${arch} clang_rt.asan-dynamic-${arch}-version-list)
 
     if (SANITIZER_USE_SYMBOLS AND NOT ${arch} STREQUAL "i386")
       add_sanitizer_rt_symbols(clang_rt.asan_cxx


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