[clang] f59d6f5 - [clang][test] Add test for stack_protector_ignore in system macros (#213770)

[via cfe-commits]

Author: Usama Hameed
Date: 2026-08-04T11:49:29-07:00
New Revision: f59d6f5f866b97413510fa119144651fbbbc7123

URL: https://github.com/llvm/llvm-project/commit/f59d6f5f866b97413510fa119144651fbbbc7123
DIFF: https://github.com/llvm/llvm-project/commit/f59d6f5f866b97413510fa119144651fbbbc7123.diff

LOG: [clang][test] Add test for stack_protector_ignore in system macros (#213770)

d3184bc6c6a8 ("[clang] Don't warn on stack_protector_ignore in system
macros") added SuppressInSystemMacro to
warn_stack_protection_ignore_attribute but only added an LLVM CodeGen
test for the stack-protector metadata, so the diagnostic change itself
was untested.

Add a test using the self-include system_header idiom: the attribute
from a system header macro does not warn under -fstack-protector-all,
while one written in user code still does.

rdar://183962985

Added: 
    clang/test/CodeGen/stack-protector-system-macro.c

Modified: 
    

Removed: 
    


################################################################################
diff  --git a/clang/test/CodeGen/stack-protector-system-macro.c b/clang/test/CodeGen/stack-protector-system-macro.c
new file mode 100644
index 0000000000000..9a978d9e6f7a2
--- /dev/null
+++ b/clang/test/CodeGen/stack-protector-system-macro.c
@@ -0,0 +1,43 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin -emit-llvm-only -verify \
+// RUN:   -stack-protector 3 -Wignored-attributes %s
+
+// Test that 'stack_protector_ignore' attributes coming from system header
+// macros don't trigger -Wignored-attributes under -fstack-protector-all.
+// The attribute is not actionable at the expansion site: the user cannot
+// remove it without editing the system header.
+
+#ifdef IS_SYSHEADER
+#pragma clang system_header
+
+#define SANITY(a) (a / 0)
+
+#define BUFFER_WITH_IGNORED_ATTR                                               \
+  __extension__({                                                              \
+    __attribute__((stack_protector_ignore)) char _buf[64];                     \
+    _buf[0] = 0;                                                               \
+  })
+
+#else
+
+#define IS_SYSHEADER
+#include __FILE__
+
+void testSanity(void) {
+  // Validate that the test is set up correctly.
+  int i = SANITY(0); // expected-warning {{division by zero is undefined}}
+  (void)i;
+}
+
+void testSystemMacro(void) {
+  // no -Wignored-attributes in system macro expansion
+  BUFFER_WITH_IGNORED_ATTR;
+}
+
+void testUserCode(void) {
+  // Written directly in user code, so it is still diagnosed.
+  __attribute__((stack_protector_ignore))
+  char buf[64]; // expected-warning {{'stack_protector_ignore' attribute ignored due to '-fstack-protector-all' option}}
+  (void)buf;
+}
+
+#endif