From 2c63cc7268fd5615997989f153e9405d0f5aaa50 Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Fri, 10 Mar 2023 10:10:24 +0100
Subject: [PATCH] c, c++, cgraphunit: Prevent duplicated -Wunused-value
warnings [PR108079]
On the following testcase, we warn with -Wunused-value twice, once
in the FEs and later on cgraphunit again with slightly different
wording.
The following patch fixes that by registering a warning suppression in the
FEs when we warn and not warning in cgraphunit anymore if that happened.
2023-03-10 Jakub Jelinek <jakub@redhat.com>
PR c/108079
gcc/
* cgraphunit.cc (check_global_declaration): Don't warn for unused
variables which have OPT_Wunused_variable warning suppressed.
gcc/c/
* c-decl.cc (pop_scope): Suppress OPT_Wunused_variable warning
after diagnosing it.
gcc/cp/
* decl.cc (poplevel): Suppress OPT_Wunused_variable warning
after diagnosing it.
gcc/testsuite/
* c-c++-common/Wunused-var-18.c: New test.
---
gcc/c/c-decl.cc | 5 ++++-
gcc/cgraphunit.cc | 1 +
gcc/cp/decl.cc | 1 +
gcc/testsuite/c-c++-common/Wunused-var-18.c | 10 ++++++++++
4 files changed, 16 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/c-c++-common/Wunused-var-18.c
diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc
index 91599658be96..e537d33f3986 100644
--- a/gcc/c/c-decl.cc
+++ b/gcc/c/c-decl.cc
@@ -1310,7 +1310,10 @@ pop_scope (void)
&& scope != external_scope)
{
if (!TREE_USED (p))
- warning (OPT_Wunused_variable, "unused variable %q+D", p);
+ {
+ warning (OPT_Wunused_variable, "unused variable %q+D", p);
+ suppress_warning (p, OPT_Wunused_variable);
+ }
else if (DECL_CONTEXT (p) == current_function_decl)
warning_at (DECL_SOURCE_LOCATION (p),
OPT_Wunused_but_set_variable,
diff --git a/gcc/cgraphunit.cc b/gcc/cgraphunit.cc
index a972900900b7..e12764f2f906 100644
--- a/gcc/cgraphunit.cc
+++ b/gcc/cgraphunit.cc
@@ -1120,6 +1120,7 @@ check_global_declaration (symtab_node *snode)
&& (TREE_CODE (decl) != FUNCTION_DECL
|| (!DECL_STATIC_CONSTRUCTOR (decl)
&& !DECL_STATIC_DESTRUCTOR (decl)))
+ && (! VAR_P (decl) || !warning_suppressed_p (decl, OPT_Wunused_variable))
/* Otherwise, ask the language. */
&& lang_hooks.decls.warn_unused_global (decl))
warning_at (DECL_SOURCE_LOCATION (decl),
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index b1603859644f..51199bb311a8 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -693,6 +693,7 @@ poplevel (int keep, int reverse, int functionbody)
else
warning_at (DECL_SOURCE_LOCATION (decl),
OPT_Wunused_variable, "unused variable %qD", decl);
+ suppress_warning (decl, OPT_Wunused_variable);
}
else if (DECL_CONTEXT (decl) == current_function_decl
// For -Wunused-but-set-variable leave references alone.
diff --git a/gcc/testsuite/c-c++-common/Wunused-var-18.c b/gcc/testsuite/c-c++-common/Wunused-var-18.c
new file mode 100644
index 000000000000..5ff772b74c1d
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/Wunused-var-18.c
@@ -0,0 +1,10 @@
+/* PR c/108079 */
+/* { dg-do compile } */
+/* { dg-options "-Wunused-variable" } */
+
+int
+main ()
+{
+ static int x; /* { dg-warning "unused variable 'x'" } */
+ /* { dg-bogus "'x' defined but not used" "" { target *-*-* } .-1 } */
+}
--
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