[PATCH] D146745: [sanitizers] Explainer about dyld and weak overrides on Darwin.

[Roy Sundahl via Phabricator via llvm-commits]

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rdar://103453678


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D146745

Files:
  llvm/docs/ReleaseNotes.rst


Index: llvm/docs/ReleaseNotes.rst
===================================================================
--- llvm/docs/ReleaseNotes.rst
+++ llvm/docs/ReleaseNotes.rst
@@ -231,6 +231,17 @@
 
 Changes to Sanitizers
 ---------------------
+* For users of weak overrides on Darwin, the dynamic linker (dyld) will only
+  consider symbols from other mach-o modules (dylibs and main executable), which
+  themselves contain at least one weak symbol. A consequence of this is that if
+  your main program contains an intended override of a sanitizer weak reference,
+  then it must contain at least one weak symbol. (NB: This symbol may be the
+  intended override itself). ::
+
+    Example:
+      __attribute__((weak,unused)) unsigned __enableOverrides;
+    or:
+      __attribute__((weak)) void __asan_on_error(void) {...}
 
 Other Changes
 -------------


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