Disable weak attribute when absl compiled as windows DLL
PiperOrigin-RevId: 659987892
Change-Id: I8cb64c7569abe932851ab52d68e3b44c0c008ece
diff --git a/absl/base/attributes.h b/absl/base/attributes.h
index 5ea5ee3..c5f35be 100644
--- a/absl/base/attributes.h
+++ b/absl/base/attributes.h
@@ -133,12 +133,14 @@
// Tags a function as weak for the purposes of compilation and linking.
// Weak attributes did not work properly in LLVM's Windows backend before
// 9.0.0, so disable them there. See https://bugs.llvm.org/show_bug.cgi?id=37598
-// for further information.
+// for further information. Weak attributes do not work across DLL boundary.
// The MinGW compiler doesn't complain about the weak attribute until the link
// step, presumably because Windows doesn't use ELF binaries.
-#if (ABSL_HAVE_ATTRIBUTE(weak) || \
- (defined(__GNUC__) && !defined(__clang__))) && \
- (!defined(_WIN32) || (defined(__clang__) && __clang_major__ >= 9)) && \
+#if (ABSL_HAVE_ATTRIBUTE(weak) || \
+ (defined(__GNUC__) && !defined(__clang__))) && \
+ (!defined(_WIN32) || \
+ (defined(__clang__) && __clang_major__ >= 9 && \
+ !defined(ABSL_BUILD_DLL) && !defined(ABSL_CONSUME_DLL))) && \
!defined(__MINGW32__)
#undef ABSL_ATTRIBUTE_WEAK
#define ABSL_ATTRIBUTE_WEAK __attribute__((weak))
