https://gcc.gnu.org/g:821d56100e1110ab6a166f50819522254eb30923
commit r15-4191-g821d56100e1110ab6a166f50819522254eb30923
Author: Ken Matsui <kmat...@gcc.gnu.org>
Date: Fri Mar 1 22:10:55 2024 -0800
gcc, libcpp: Add warning switch for "#pragma once in main file" [PR89808]
This patch adds a warning switch for "#pragma once in main file". The
warning option name is Wpragma-once-outside-header, which is the same
as Clang provides.
PR preprocessor/89808
gcc/c-family/ChangeLog:
* c.opt (Wpragma_once_outside_header): Define new option.
* c.opt.urls: Regenerate.
gcc/ChangeLog:
* doc/invoke.texi (Warning Options): Document
-Wno-pragma-once-outside-header.
libcpp/ChangeLog:
* include/cpplib.h (cpp_warning_reason): Define
CPP_W_PRAGMA_ONCE_OUTSIDE_HEADER.
* directives.cc (do_pragma_once): Use
CPP_W_PRAGMA_ONCE_OUTSIDE_HEADER.
gcc/testsuite/ChangeLog:
* g++.dg/warn/Wno-pragma-once-outside-header.C: New test.
* g++.dg/warn/Wpragma-once-outside-header.C: New test.
Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org>
Reviewed-by: Marek Polacek <pola...@redhat.com>
Diff:
---
gcc/c-family/c.opt | 4 ++++
gcc/c-family/c.opt.urls | 3 +++
gcc/doc/invoke.texi | 10 ++++++++--
gcc/testsuite/g++.dg/warn/Wno-pragma-once-outside-header.C | 5 +++++
gcc/testsuite/g++.dg/warn/Wpragma-once-outside-header.C | 6 ++++++
libcpp/directives.cc | 3 ++-
libcpp/include/cpplib.h | 3 ++-
7 files changed, 30 insertions(+), 4 deletions(-)
diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index 9d1fccadbf99..1f2e72a0bb73 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -1214,6 +1214,10 @@ Wpragmas
C ObjC C++ ObjC++ Var(warn_pragmas) Init(1) Warning
Warn about misuses of pragmas.
+Wpragma-once-outside-header
+C ObjC C++ ObjC++ Var(warn_pragma_once_outside_header)
CppReason(CPP_W_PRAGMA_ONCE_OUTSIDE_HEADER) Init(1) Warning
+Warn about #pragma once outside of a header.
+
Wprio-ctor-dtor
C ObjC C++ ObjC++ Var(warn_prio_ctor_dtor) Init(1) Warning
Warn if constructor or destructors with priorities from 0 to 100 are used.
diff --git a/gcc/c-family/c.opt.urls b/gcc/c-family/c.opt.urls
index b77575bc8969..b1593ef41401 100644
--- a/gcc/c-family/c.opt.urls
+++ b/gcc/c-family/c.opt.urls
@@ -684,6 +684,9 @@
UrlSuffix(gcc/Warning-Options.html#index-Wno-pointer-to-int-cast)
Wpragmas
UrlSuffix(gcc/Warning-Options.html#index-Wno-pragmas)
+Wpragma-once-outside-header
+UrlSuffix(gcc/Warning-Options.html#index-Wno-pragma-once-outside-header)
+
Wprio-ctor-dtor
UrlSuffix(gcc/Warning-Options.html#index-Wno-prio-ctor-dtor)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index b2f16b45eaf4..c0c8bf1c29a9 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -395,8 +395,8 @@ Objective-C and Objective-C++ Dialects}.
-Wpacked -Wno-packed-bitfield-compat -Wpacked-not-aligned -Wpadded
-Wparentheses -Wno-pedantic-ms-format
-Wpointer-arith -Wno-pointer-compare -Wno-pointer-to-int-cast
--Wno-pragmas -Wno-prio-ctor-dtor -Wredundant-decls
--Wrestrict -Wno-return-local-addr -Wreturn-type
+-Wno-pragmas -Wno-pragma-once-outside-header -Wno-prio-ctor-dtor
+-Wredundant-decls -Wrestrict -Wno-return-local-addr -Wreturn-type
-Wno-scalar-storage-order -Wsequence-point
-Wshadow -Wshadow=global -Wshadow=local -Wshadow=compatible-local
-Wno-shadow-ivar
@@ -8147,6 +8147,12 @@ Do not warn about misuses of pragmas, such as incorrect
parameters,
invalid syntax, or conflicts between pragmas. See also
@option{-Wunknown-pragmas}.
+@opindex Wno-pragma-once-outside-header
+@opindex Wpragma-once-outside-header
+@item -Wno-pragma-once-outside-header
+Do not warn when @code{#pragma once} is used in a file that is not a header
+file, such as a main file.
+
@opindex Wno-prio-ctor-dtor
@opindex Wprio-ctor-dtor
@item -Wno-prio-ctor-dtor
diff --git a/gcc/testsuite/g++.dg/warn/Wno-pragma-once-outside-header.C
b/gcc/testsuite/g++.dg/warn/Wno-pragma-once-outside-header.C
new file mode 100644
index 000000000000..b5be4d25a9d8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wno-pragma-once-outside-header.C
@@ -0,0 +1,5 @@
+// { dg-do assemble }
+// { dg-options "-Wno-pragma-once-outside-header" }
+
+#pragma once
+int main() {}
diff --git a/gcc/testsuite/g++.dg/warn/Wpragma-once-outside-header.C
b/gcc/testsuite/g++.dg/warn/Wpragma-once-outside-header.C
new file mode 100644
index 000000000000..448e26102919
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wpragma-once-outside-header.C
@@ -0,0 +1,6 @@
+// { dg-do assemble }
+// { dg-options "-Werror=pragma-once-outside-header" }
+// { dg-message "some warnings being treated as errors" "" {target "*-*-*"} 0 }
+
+#pragma once // { dg-error "'#pragma once' in main file" }
+int main() {}
diff --git a/libcpp/directives.cc b/libcpp/directives.cc
index c30087c7a1d9..95095b08eafe 100644
--- a/libcpp/directives.cc
+++ b/libcpp/directives.cc
@@ -2074,7 +2074,8 @@ static void
do_pragma_once (cpp_reader *pfile)
{
if (_cpp_in_main_source_file (pfile))
- cpp_error (pfile, CPP_DL_WARNING, "#pragma once in main file");
+ cpp_warning (pfile, CPP_W_PRAGMA_ONCE_OUTSIDE_HEADER,
+ "%<#pragma once%> in main file");
check_eol (pfile, false);
_cpp_mark_file_once_only (pfile, pfile->buffer->file);
diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
index fbddc34b6af0..bff660174f5f 100644
--- a/libcpp/include/cpplib.h
+++ b/libcpp/include/cpplib.h
@@ -714,7 +714,8 @@ enum cpp_warning_reason {
CPP_W_BIDIRECTIONAL,
CPP_W_INVALID_UTF8,
CPP_W_UNICODE,
- CPP_W_HEADER_GUARD
+ CPP_W_HEADER_GUARD,
+ CPP_W_PRAGMA_ONCE_OUTSIDE_HEADER
};
/* Callback for header lookup for HEADER, which is the name of a
