Guard against undefined weak symbols before Mac OS X 10.9 (PR sanitizer/82825)

	PR sanitizer/82825
	* sanitizer_common/sanitizer_internal_defs.h: Cherry-pick upstream
	r??????.

From-SVN: r256813

diff --git a/libsanitizer/ChangeLog b/libsanitizer/ChangeLog
index 2f57f6acd8252b9b9f823d165a2288506323baed..0f2192aed4d553bcdec8222beabc38379fe7dfcd 100644 (file)
--- a/libsanitizer/ChangeLog
+++ b/libsanitizer/ChangeLog
@@ -1,3 +1,9 @@
+2018-01-17  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
+
+       PR sanitizer/82825
+       * sanitizer_common/sanitizer_internal_defs.h: Cherry-pick upstream
+       r??????.
+
 2018-01-13  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
        PR sanitizer/82824

diff --git a/libsanitizer/sanitizer_common/sanitizer_internal_defs.h b/libsanitizer/sanitizer_common/sanitizer_internal_defs.h
index ef405dec04854d551fcc26c172c60ea16b418949..edd6a21c1221cf3d8ddb6c066670dd0acd38e693 100644 (file)
--- a/libsanitizer/sanitizer_common/sanitizer_internal_defs.h
+++ b/libsanitizer/sanitizer_common/sanitizer_internal_defs.h
@@ -63,7 +63,13 @@
 // SANITIZER_SUPPORTS_WEAK_HOOKS means that we support real weak functions that
 // will evaluate to a null pointer when not defined.
 #ifndef SANITIZER_SUPPORTS_WEAK_HOOKS
-#if (SANITIZER_LINUX || SANITIZER_MAC) && !SANITIZER_GO
+#if SANITIZER_LINUX && !SANITIZER_GO
+# define SANITIZER_SUPPORTS_WEAK_HOOKS 1
+// Before Xcode 4.5, the Darwin linker doesn't reliably support undefined
+// weak symbols.  Mac OS X 10.9/Darwin 13 is the first release only supported
+// by Xcode >= 4.5.
+#elif SANITIZER_MAC && \
+    __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 1090 && !SANITIZER_GO
 # define SANITIZER_SUPPORTS_WEAK_HOOKS 1
 #else
 # define SANITIZER_SUPPORTS_WEAK_HOOKS 0