Empirically, omitted parameter names are difficult to catch in code
review. With this change, projects can build with
-Werror=missing-parameter-name, to avoid this unnecessary
incompatibility with older GCC versions. The existing
-pedantic-errors option is too broad for that because it also flags
widely used and widely available GCC extensions. Likewise for
-Werror=c11-c23-compat.
gcc/
* c-family/c-opts.cc (c_common_post_options): Initialize
warn_missing_parameter_name.
* c-family/c.opt (Wmissing-parameter-name): New.
* c/c-decl.cc (store_parm_decls_newstyle): Use
OPT_Wmissing_parameter_name for missing parameter name
warning.
* c/c-errors.cc (pedwarn_c11): Enable fine-grained warning
control via the option_id argument.
* doc/invoke.texi: Document Wmissing-parameter-name.
* testsuite/gcc.dg/Wmissing-parameter-name-1.c: New test.
* testsuite/gcc.dg/Wmissing-parameter-name-2.c: New test.
* testsuite/gcc.dg/Wmissing-parameter-name-3.c: New test.
---
gcc/c-family/c-opts.cc | 7 +++++++
gcc/c-family/c.opt | 4 ++++
gcc/c/c-decl.cc | 2 +-
gcc/c/c-errors.cc | 17 ++++++++++++-----
gcc/doc/invoke.texi | 24 ++++++++++++++++++------
gcc/testsuite/gcc.dg/Wmissing-parameter-name-1.c | 7 +++++++
gcc/testsuite/gcc.dg/Wmissing-parameter-name-2.c | 7 +++++++
gcc/testsuite/gcc.dg/Wmissing-parameter-name-3.c | 7 +++++++
8 files changed, 63 insertions(+), 12 deletions(-)
diff --git a/gcc/c-family/c-opts.cc b/gcc/c-family/c-opts.cc
index afb963de061..868b03cc410 100644
--- a/gcc/c-family/c-opts.cc
+++ b/gcc/c-family/c-opts.cc
@@ -985,6 +985,13 @@ c_common_post_options (const char **pfilename)
if (warn_shift_overflow == -1)
warn_shift_overflow = cxx_dialect >= cxx11 || flag_isoc99;
+ /* -Wmissing-parameter-name is enabled by -pedantic before C23,
+ and for -Wc11-c23-compat. */
+ if (warn_missing_parameter_name == -1)
+ warn_missing_parameter_name
+ = ((pedantic && !flag_isoc23 && warn_c11_c23_compat != 0)
+ || warn_c11_c23_compat > 0);
+
/* -Wshift-negative-value is enabled by -Wextra in C99 and C++11 to C++17
modes. */
if (warn_shift_negative_value == -1)
diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index d5608ec363c..eb4e5e8c500 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -1007,6 +1007,10 @@ Wmissing-include-dirs
C ObjC C++ ObjC++ CPP(warn_missing_include_dirs)
CppReason(CPP_W_MISSING_INCLUDE_DIRS) Var(cpp_warn_missing_include_dirs)
Init(0) Warning
Warn about user-specified include directories that do not exist.
+Wmissing-parameter-name
+C ObjC Var(warn_missing_parameter_name) Init(-1) Warning
+Warn about function definitions omitting parameter names.
+
Wmissing-parameter-type
C ObjC Var(warn_missing_parameter_type) Warning EnabledBy(Wextra)
Warn about function parameters declared without a type specifier in K&R-style
functions.
diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc
index 3733ecfc13f..7ab5e6f920e 100644
--- a/gcc/c/c-decl.cc
+++ b/gcc/c/c-decl.cc
@@ -10946,7 +10946,7 @@ store_parm_decls_newstyle (tree fndecl, const struct
c_arg_info *arg_info)
warn_if_shadowing (decl);
}
else
- pedwarn_c11 (DECL_SOURCE_LOCATION (decl), OPT_Wpedantic,
+ pedwarn_c11 (DECL_SOURCE_LOCATION (decl), OPT_Wmissing_parameter_name,
"ISO C does not support omitting parameter names in "
"function definitions before C23");
}
diff --git a/gcc/c/c-errors.cc b/gcc/c/c-errors.cc
index c6b7c108354..77f008eba1c 100644
--- a/gcc/c/c-errors.cc
+++ b/gcc/c/c-errors.cc
@@ -70,7 +70,10 @@ pedwarn_c23 (location_t location,
otherwise issue warning MSGID if -Wc11-c23-compat is specified.
This function is supposed to be used for matters that are allowed in
ISO C23 but not supported in ISO C11, thus we explicitly don't pedwarn
- when C23 is specified. */
+ when C23 is specified.
+
+ Additionally, warn if OPTION_ID is not OPT_Wpedantic nor
+ OPT_Wc11_c23_compat. */
bool
pedwarn_c11 (location_t location,
@@ -83,14 +86,18 @@ pedwarn_c11 (location_t location,
rich_location richloc (line_table, location);
va_start (ap, gmsgid);
- /* If desired, issue the C11/C23 compat warning, which is more specific
- than -pedantic. */
- if (warn_c11_c23_compat > 0)
+ /* If desired, issue the C11/C23 compat warning, which is more specific than
+ -pedantic, or the warning specified by option_id. */
+ if (warn_c11_c23_compat > 0 || (option_id.m_idx != OPT_Wpedantic
+ && option_id.m_idx != OPT_Wc11_c23_compat))
{
diagnostic_set_info (&diagnostic, gmsgid, &ap, &richloc,
(pedantic && !flag_isoc23)
? DK_PEDWARN : DK_WARNING);
- diagnostic.option_id = OPT_Wc11_c23_compat;
+ if (option_id == OPT_Wpedantic)
+ diagnostic.option_id = OPT_Wc11_c23_compat;
+ else
+ diagnostic.option_id = option_id;
warned = diagnostic_report_diagnostic (global_dc, &diagnostic);
}
/* -Wno-c11-c23-compat suppresses even the pedwarns. */
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index aebcc9082ff..2e8913a9395 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -517,12 +517,12 @@ Objective-C and Objective-C++ Dialects}.
}
@item C and Objective-C-only Warning Options
-@gccoptlist{-Wbad-function-cast -Wmissing-declarations
--Wmissing-parameter-type -Wdeclaration-missing-parameter-type
--Wmissing-prototypes -Wmissing-variable-declarations
--Wnested-externs -Wold-style-declaration -Wold-style-definition
--Wstrict-prototypes -Wtraditional -Wtraditional-conversion
--Wdeclaration-after-statement -Wpointer-sign}
+@gccoptlist{-Wbad-function-cast -Wmissing-declarations
+-Wmissing-parameter-name -Wmissing-parameter-type
+-Wdeclaration-missing-parameter-type -Wmissing-prototypes
+-Wmissing-variable-declarations -Wnested-externs -Wold-style-declaration
+-Wold-style-definition -Wstrict-prototypes -Wtraditional
+-Wtraditional-conversion -Wdeclaration-after-statement -Wpointer-sign}
@item Debugging Options
@xref{Debugging Options,,Options for Debugging Your Program}.
@@ -6273,6 +6273,7 @@ name is still supported, but the newer name is more
descriptive.)
-Wimplicit-fallthrough=3
-Wmaybe-uninitialized
-Wmissing-field-initializers
+-Wmissing-parameter-name @r{(C/ObjC only)}
-Wmissing-parameter-type @r{(C/ObjC only)}
-Wold-style-declaration @r{(C/ObjC only)}
-Woverride-init @r{(C/ObjC only)}
@@ -9929,6 +9930,17 @@ is not considered an old-style definition in C23 mode,
because it is
equivalent to @samp{(void)} in that case, but is considered an
old-style definition for older standards.
+@opindex Wmissing-parameter-name
+@opindex Wno-missing-parameter-name
+@item -Wmissing-parameter-name @r{(C and Objective-C only)}
+Warn if a function definition omits are parameter name, specifying only
+its type. This can be used to document that a parameter is unused
+in the definition. It is part of C23 and later dialects of C,
+and available as a GCC extension in all other dialects.
+
+This warning is also enabled by @option{-Wc11-c23-compat}. It is turned
+into an error by @option{-pedantic-errors}.
+
@opindex Wmissing-parameter-type
@opindex Wno-missing-parameter-type
@item -Wmissing-parameter-type @r{(C and Objective-C only)}
diff --git a/gcc/testsuite/gcc.dg/Wmissing-parameter-name-1.c
b/gcc/testsuite/gcc.dg/Wmissing-parameter-name-1.c
new file mode 100644
index 00000000000..b804f7b3d4d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wmissing-parameter-name-1.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-Wmissing-parameter-name" } */
+
+int
+f (int) /* { dg-warning "omitting parameter names" } */
+{
+}
diff --git a/gcc/testsuite/gcc.dg/Wmissing-parameter-name-2.c
b/gcc/testsuite/gcc.dg/Wmissing-parameter-name-2.c
new file mode 100644
index 00000000000..a02083ffe27
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wmissing-parameter-name-2.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c11 -pedantic -Wno-missing-parameter-name" } */
+
+int
+f (int)
+{
+}
diff --git a/gcc/testsuite/gcc.dg/Wmissing-parameter-name-3.c
b/gcc/testsuite/gcc.dg/Wmissing-parameter-name-3.c
new file mode 100644
index 00000000000..b89d886637e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wmissing-parameter-name-3.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-Wc11-c23-compat -Wno-missing-parameter-name" } */
+
+int
+f (int)
+{
+}
base-commit: 1a4c5643a5911d130dfab9a064222baeeb7f9be7
