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-rw-r--r--compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h38
1 files changed, 36 insertions, 2 deletions
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h b/compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h
index 5338f79423c..24e482e53e4 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h
@@ -22,7 +22,6 @@
// Only use SANITIZER_*ATTRIBUTE* before the function return type!
#if SANITIZER_WINDOWS
# define SANITIZER_INTERFACE_ATTRIBUTE __declspec(dllexport)
-// FIXME find out what we need on Windows, if anything.
# define SANITIZER_WEAK_ATTRIBUTE
#elif SANITIZER_GO
# define SANITIZER_INTERFACE_ATTRIBUTE
@@ -32,11 +31,46 @@
# define SANITIZER_WEAK_ATTRIBUTE __attribute__((weak))
#endif
-#if (SANITIZER_LINUX || SANITIZER_MAC || SANITIZER_WINDOWS) && !SANITIZER_GO
+//--------------------------- WEAK FUNCTIONS ---------------------------------//
+// When working with weak functions, to simplify the code and make it more
+// portable, when possible define a default implementation using this macro:
+//
+// SANITIZER_INTERFACE_WEAK_DEF(<return_type>, <name>, <parameter list>)
+//
+// For example:
+// SANITIZER_INTERFACE_WEAK_DEF(bool, compare, int a, int b) { return a > b; }
+//
+#if SANITIZER_WINDOWS
+#include "sanitizer_win_defs.h"
+# define SANITIZER_INTERFACE_WEAK_DEF(ReturnType, Name, ...) \
+ WIN_WEAK_EXPORT_DEF(ReturnType, Name, __VA_ARGS__)
+#else
+# define SANITIZER_INTERFACE_WEAK_DEF(ReturnType, Name, ...) \
+ extern "C" SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE \
+ ReturnType Name(__VA_ARGS__)
+#endif
+
+// SANITIZER_SUPPORTS_WEAK_HOOKS means that we support real weak functions that
+// will evaluate to a null pointer when not defined.
+#if (SANITIZER_LINUX || SANITIZER_MAC) && !SANITIZER_GO
# define SANITIZER_SUPPORTS_WEAK_HOOKS 1
#else
# define SANITIZER_SUPPORTS_WEAK_HOOKS 0
#endif
+// For some weak hooks that will be called very often and we want to avoid the
+// overhead of executing the default implementation when it is not necessary,
+// we can use the flag SANITIZER_SUPPORTS_WEAK_HOOKS to only define the default
+// implementation for platforms that doesn't support weak symbols. For example:
+//
+// #if !SANITIZER_SUPPORT_WEAK_HOOKS
+// SANITIZER_INTERFACE_WEAK_DEF(bool, compare_hook, int a, int b) {
+// return a > b;
+// }
+// #endif
+//
+// And then use it as: if (compare_hook) compare_hook(a, b);
+//----------------------------------------------------------------------------//
+
// We can use .preinit_array section on Linux to call sanitizer initialization
// functions very early in the process startup (unless PIC macro is defined).
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