[PATCH] D50059: [CMake] Fix bug in `add_weak_symbols()` function.

[Dan Liew via Phabricator via llvm-commits]

delcypher created this revision.
delcypher added reviewers: fjricci, kubamracek, george.karpenkov, eugenis, compnerd.
Herald added subscribers: Sanitizers, mgorny.

[CMake] Fix bug in `add_weak_symbols()` function.

Previously the the `weak_symbols.txt` files could be modified and the
build system wouldn't update the link flags automatically. Instead the
developer had to know to reconfigure CMake manually.

This is now fixed by telling CMake that the file being used to
read weak symbols from is a configure-time dependency.


Repository:
  rCRT Compiler Runtime

https://reviews.llvm.org/D50059

Files:
  cmake/Modules/SanitizerUtils.cmake


Index: cmake/Modules/SanitizerUtils.cmake
===================================================================
--- cmake/Modules/SanitizerUtils.cmake
+++ cmake/Modules/SanitizerUtils.cmake
@@ -51,7 +51,15 @@
 # This function is only used on Darwin, where undefined symbols must be specified
 # in the linker invocation.
 function(add_weak_symbols libname link_flags)
-  file(STRINGS "${COMPILER_RT_SOURCE_DIR}/lib/${libname}/weak_symbols.txt" WEAK_SYMBOLS)
+  set(weak_symbols_file "${COMPILER_RT_SOURCE_DIR}/lib/${libname}/weak_symbols.txt")
+  file(STRINGS  "${weak_symbols_file}" WEAK_SYMBOLS)
+  # Add this file as a configure-time dependency so that changes to this
+  # file trigger a re-configure. This is necessary so that `${link_flags}`
+  # is changed when appropriate.
+  set_property(
+    DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
+    APPEND
+    PROPERTY CMAKE_CONFIGURE_DEPENDS "${weak_symbols_file}")
   set(local_link_flags ${${link_flags}})
   foreach(SYMBOL ${WEAK_SYMBOLS})
     set(local_link_flags ${local_link_flags} -Wl,-U,${SYMBOL})


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