[clang] [Clang] Update missing varargs arg extension warnings (PR #84520)
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Fri Mar 8 09:23:46 PST 2024
https://github.com/Sirraide created https://github.com/llvm/llvm-project/pull/84520
This updates a few warnings that were diagnosing no arguments for a `...` variadic macro parameter as a GNU extension when it actually is a C++20/C23 extension now.
This fixes #84495.
>From 502692869e3105bb2c55955bc4baff63b1475770 Mon Sep 17 00:00:00 2001
From: Sirraide <aeternalmail at gmail.com>
Date: Fri, 8 Mar 2024 18:15:07 +0100
Subject: [PATCH] [Clang] Update missing varargs arg extension warnings
---
clang/docs/ReleaseNotes.rst | 3 +++
.../include/clang/Basic/DiagnosticLexKinds.td | 13 ++++++++++---
clang/lib/Lex/PPMacroExpansion.cpp | 13 ++++++++++---
clang/test/C/C2x/n2975.c | 4 ++--
clang/test/Lexer/gnu-flags.c | 2 --
clang/test/Preprocessor/empty_va_arg.cpp | 18 +++++++++++-------
clang/test/Preprocessor/macro_fn.c | 4 ++--
7 files changed, 38 insertions(+), 19 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 0ff4a93b15ea8f..ffc88e79961ce6 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -212,6 +212,9 @@ Improvements to Clang's diagnostics
- Clang now diagnoses lambda function expressions being implicitly cast to boolean values, under ``-Wpointer-bool-conversion``.
Fixes #GH82512.
+- Clang now correctly diagnoses no arguments to a variadic macro parameter as a C23/C++20 extension.
+ Fixes #GH84495.
+
Improvements to Clang's time-trace
----------------------------------
diff --git a/clang/include/clang/Basic/DiagnosticLexKinds.td b/clang/include/clang/Basic/DiagnosticLexKinds.td
index d7c172e6546351..ad6bacfb118d49 100644
--- a/clang/include/clang/Basic/DiagnosticLexKinds.td
+++ b/clang/include/clang/Basic/DiagnosticLexKinds.td
@@ -465,9 +465,16 @@ def err_embedded_directive : Error<
def ext_embedded_directive : Extension<
"embedding a directive within macro arguments has undefined behavior">,
InGroup<DiagGroup<"embedded-directive">>;
-def ext_missing_varargs_arg : Extension<
- "must specify at least one argument for '...' parameter of variadic macro">,
- InGroup<GNUZeroVariadicMacroArguments>;
+def ext_c_missing_varargs_arg : Extension<
+ "passing no argument for the '...' parameter of a variadic macro is "
+ "a C23 extension">, InGroup<C23>;
+def ext_cxx_missing_varargs_arg : Extension<
+ "passing no argument for the '...' parameter of a variadic macro is "
+ "a C++20 extension">, InGroup<CXX20>;
+def warn_c17_compat_missing_varargs_arg : Warning<
+ "passing no argument for the '...' parameter of a variadic macro is "
+ "incompatible with C standards before C23">,
+ InGroup<CPre23Compat>, DefaultIgnore;
def warn_cxx17_compat_missing_varargs_arg : Warning<
"passing no argument for the '...' parameter of a variadic macro is "
"incompatible with C++ standards before C++20">,
diff --git a/clang/lib/Lex/PPMacroExpansion.cpp b/clang/lib/Lex/PPMacroExpansion.cpp
index 3017461dc66e86..3cde001e84760e 100644
--- a/clang/lib/Lex/PPMacroExpansion.cpp
+++ b/clang/lib/Lex/PPMacroExpansion.cpp
@@ -995,9 +995,16 @@ MacroArgs *Preprocessor::ReadMacroCallArgumentList(Token &MacroName,
if (!MI->hasCommaPasting()) {
// C++20 allows this construct, but standards before C++20 and all C
// standards do not allow the construct (we allow it as an extension).
- Diag(Tok, getLangOpts().CPlusPlus20
- ? diag::warn_cxx17_compat_missing_varargs_arg
- : diag::ext_missing_varargs_arg);
+ unsigned ID;
+ if (getLangOpts().CPlusPlus20)
+ ID = diag::warn_cxx17_compat_missing_varargs_arg;
+ else if (getLangOpts().CPlusPlus)
+ ID = diag::ext_cxx_missing_varargs_arg;
+ else if (getLangOpts().C23)
+ ID = diag::warn_c17_compat_missing_varargs_arg;
+ else
+ ID = diag::ext_c_missing_varargs_arg;
+ Diag(Tok, ID);
Diag(MI->getDefinitionLoc(), diag::note_macro_here)
<< MacroName.getIdentifierInfo();
}
diff --git a/clang/test/C/C2x/n2975.c b/clang/test/C/C2x/n2975.c
index 5fc641dd66e781..2269400fe47c34 100644
--- a/clang/test/C/C2x/n2975.c
+++ b/clang/test/C/C2x/n2975.c
@@ -11,7 +11,7 @@
void func(...) { // expected-warning {{'...' as the only parameter of a function is incompatible with C standards before C23}}
// Show that va_start doesn't require the second argument in C23 mode.
va_list list;
- va_start(list); // FIXME: it would be nice to issue a portability warning to C17 and earlier here.
+ va_start(list); // expected-warning {{passing no argument for the '...' parameter of a variadic macro is incompatible with C standards before C23}} expected-note@* {{macro 'va_start' defined here}}
va_end(list);
// Show that va_start doesn't expand or evaluate the second argument.
@@ -26,7 +26,7 @@ void func(...) { // expected-warning {{'...' as the only parameter of a function
__builtin_va_start(list); // expected-error {{too few arguments to function call, expected 2, have 1}}
// Verify that the return type of a call to va_start is 'void'.
- _Static_assert(__builtin_types_compatible_p(__typeof__(va_start(list)), void), "");
+ _Static_assert(__builtin_types_compatible_p(__typeof__(va_start(list)), void), ""); // expected-warning {{passing no argument for the '...' parameter of a variadic macro is incompatible with C standards before C23}} expected-note@* {{macro 'va_start' defined here}}
_Static_assert(__builtin_types_compatible_p(__typeof__(__builtin_va_start(list, 0)), void), "");
}
diff --git a/clang/test/Lexer/gnu-flags.c b/clang/test/Lexer/gnu-flags.c
index 384339fc859429..4d6d216b101f4a 100644
--- a/clang/test/Lexer/gnu-flags.c
+++ b/clang/test/Lexer/gnu-flags.c
@@ -17,8 +17,6 @@
#if ALL || ZEROARGS
-// expected-warning at +9 {{must specify at least one argument for '...' parameter of variadic macro}}
-// expected-note at +4 {{macro 'efoo' defined here}}
// expected-warning at +3 {{token pasting of ',' and __VA_ARGS__ is a GNU extension}}
#endif
diff --git a/clang/test/Preprocessor/empty_va_arg.cpp b/clang/test/Preprocessor/empty_va_arg.cpp
index 2ee431f6bde838..7c7d49d8fb1632 100644
--- a/clang/test/Preprocessor/empty_va_arg.cpp
+++ b/clang/test/Preprocessor/empty_va_arg.cpp
@@ -1,12 +1,16 @@
-// RUN: %clang_cc1 -Eonly -std=c++17 -pedantic -verify %s
-// RUN: %clang_cc1 -Eonly -std=c17 -pedantic -verify -x c %s
-// RUN: %clang_cc1 -Eonly -std=c++20 -pedantic -Wpre-c++20-compat -verify=compat %s
+// RUN: %clang_cc1 -Eonly -std=c17 -pedantic -verify=c17,expected -x c %s
+// RUN: %clang_cc1 -Eonly -std=c23 -pedantic -Wpre-c23-compat -verify=c23,expected -x c %s
+// RUN: %clang_cc1 -Eonly -std=c++17 -pedantic -verify=cxx17,expected %s
+// RUN: %clang_cc1 -Eonly -std=c++20 -pedantic -Wpre-c++20-compat -verify=cxx20,expected %s
-#define FOO(x, ...) // expected-note {{macro 'FOO' defined here}} \
- // compat-note {{macro 'FOO' defined here}}
+// silent-no-diagnostics
+
+#define FOO(x, ...) // expected-note {{macro 'FOO' defined here}}
int main() {
- FOO(42) // expected-warning {{must specify at least one argument for '...' parameter of variadic macro}} \
- // compat-warning {{passing no argument for the '...' parameter of a variadic macro is incompatible with C++ standards before C++20}}
+ FOO(42) // c17-warning {{passing no argument for the '...' parameter of a variadic macro is a C23 extension}} \
+ // cxx17-warning {{passing no argument for the '...' parameter of a variadic macro is a C++20 extension}} \
+ // c23-warning {{passing no argument for the '...' parameter of a variadic macro is incompatible with C standards before C23}} \
+ // cxx20-warning {{passing no argument for the '...' parameter of a variadic macro is incompatible with C++ standards before C++20}}
}
diff --git a/clang/test/Preprocessor/macro_fn.c b/clang/test/Preprocessor/macro_fn.c
index 5f4ea0e26d5d8b..81d83632140788 100644
--- a/clang/test/Preprocessor/macro_fn.c
+++ b/clang/test/Preprocessor/macro_fn.c
@@ -37,8 +37,8 @@ e(x)
e()
zero_dot()
-one_dot(x) /* empty ... argument: expected-warning {{must specify at least one argument for '...' parameter of variadic macro}} */
-one_dot() /* empty first argument, elided ...: expected-warning {{must specify at least one argument for '...' parameter of variadic macro}} */
+one_dot(x) /* empty ... argument: expected-warning {{passing no argument for the '...' parameter of a variadic macro is a C23 extension}} */
+one_dot() /* empty first argument, elided ...: expected-warning {{passing no argument for the '...' parameter of a variadic macro is a C23 extension}} */
/* Crash with function-like macro test at end of directive. */
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