From 33bf7d81b77f37e7681d280949f25d0c1e11c928 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Wed, 6 May 2026 20:58:47 +0800 Subject: [PATCH] c: Don't warn the builtin declaration of stack protection guard __stack_chk_guard is the builtin declaration of stack protection guard. Since its DECL_CONTEXT is set to current_function_decl, -Wnested-externs warns: cc1: warning: nested extern declaration of '__stack_chk_guard' [-Wnested-externs] Update pushdecl not to warn it. gcc/ PR c/121911 * c/c-decl.cc (pushdecl): Don't warn the builtin declaration of stack protection guard. gcc/testsuite/ PR c/121911 * gcc.dg/Wnested-externs-1.c: Add -mstack-protector-guard=global for x86. Signed-off-by: H.J. Lu --- gcc/c/c-decl.cc | 5 ++++- gcc/testsuite/gcc.dg/Wnested-externs-1.c | 1 + 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc index cc07e05e336..a4f13dd26fe 100644 --- a/gcc/c/c-decl.cc +++ b/gcc/c/c-decl.cc @@ -3551,8 +3551,11 @@ pushdecl (tree x) visdecl = b->decl; vistype = TREE_TYPE (visdecl); } + /* Don't warn the builtin declaration of stack protection guard. */ if (scope != file_scope - && !DECL_IN_SYSTEM_HEADER (x)) + && !DECL_IN_SYSTEM_HEADER (x) + && (!targetm.stack_protect_guard_symbol_p () + || x != targetm.stack_protect_guard ())) warning_at (locus, OPT_Wnested_externs, "nested extern declaration of %qD", x); diff --git a/gcc/testsuite/gcc.dg/Wnested-externs-1.c b/gcc/testsuite/gcc.dg/Wnested-externs-1.c index 5c4b5ddd8e2..a93c6f6006a 100644 --- a/gcc/testsuite/gcc.dg/Wnested-externs-1.c +++ b/gcc/testsuite/gcc.dg/Wnested-externs-1.c @@ -2,6 +2,7 @@ /* Origin: Joseph Myers */ /* { dg-do compile } */ /* { dg-options "-Wnested-externs" } */ +/* { dg-additional-options "-mstack-protector-guard=global" { target x86_64-*-* i?86-*-* } } */ int a; static int b; -- 2.54.0