Revert "Distinguish printf-like functions that support %m from those that don't."

This reverts commit 3a60c8ff892a8242b907f44702bfd9f1ff877d45.  Buildfarm
results show that that caused a whole bunch of new warnings on platforms
where gcc believes the local printf to be non-POSIX-compliant.  This
problem outweighs the hypothetical-anyway possibility of getting warnings
for misuse of %m.  We could use gnu_printf archetype when we've substituted
src/port/snprintf.c, but that brings us right back to the problem of not
getting warnings for %m.

A possible answer is to attack it in the other direction by insisting
that %m support be included in printf's feature set, but that will take
more investigation.  In the meantime, revert the previous change, and
update the comment for PGAC_C_PRINTF_ARCHETYPE to more fully explain
what's going on.

Discussion: https://postgr.es/m/2975.1526862605@sss.pgh.pa.us

3 files changed, 18 insertions, 22 deletions

diff --git a/src/include/c.h b/src/include/c.h
index 0a4757e29fd..1e50103095b 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -126,14 +126,10 @@
 /* GCC and XLC support format attributes */
 #if defined(__GNUC__) || defined(__IBMC__)
 #define pg_attribute_format_arg(a) __attribute__((format_arg(a)))
-/* Use for functions wrapping stdio's printf, which often doesn't take %m: */
-#define pg_attribute_printf(f,a) __attribute__((format(printf, f, a)))
-/* Use for elog/ereport, which implement %m for themselves: */
-#define pg_attribute_printf_m(f,a) __attribute__((format(PG_PRINTF_ATTRIBUTE_M, f, a)))
+#define pg_attribute_printf(f,a) __attribute__((format(PG_PRINTF_ATTRIBUTE, f, a)))
 #else
 #define pg_attribute_format_arg(a)
 #define pg_attribute_printf(f,a)
-#define pg_attribute_printf_m(f,a)
 #endif
 
 /* GCC, Sunpro and XLC support aligned, packed and noreturn */
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index 05775a3405f..b7e469670f4 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -809,8 +809,8 @@
 /* PostgreSQL major version as a string */
 #undef PG_MAJORVERSION
 
-/* Define as a format archetype that accepts %m, if available, else printf. */
-#undef PG_PRINTF_ATTRIBUTE_M
+/* Define to gnu_printf if compiler supports it, else printf. */
+#undef PG_PRINTF_ATTRIBUTE
 
 /* PostgreSQL version as a string */
 #undef PG_VERSION
diff --git a/src/include/utils/elog.h b/src/include/utils/elog.h
index 6b618a52d0a..4350b120aab 100644
--- a/src/include/utils/elog.h
+++ b/src/include/utils/elog.h
@@ -152,25 +152,25 @@ extern int	errcode(int sqlerrcode);
 extern int	errcode_for_file_access(void);
 extern int	errcode_for_socket_access(void);
 
-extern int	errmsg(const char *fmt,...) pg_attribute_printf_m(1, 2);
-extern int	errmsg_internal(const char *fmt,...) pg_attribute_printf_m(1, 2);
+extern int	errmsg(const char *fmt,...) pg_attribute_printf(1, 2);
+extern int	errmsg_internal(const char *fmt,...) pg_attribute_printf(1, 2);
 
 extern int errmsg_plural(const char *fmt_singular, const char *fmt_plural,
-			  unsigned long n,...) pg_attribute_printf_m(1, 4) pg_attribute_printf_m(2, 4);
+			  unsigned long n,...) pg_attribute_printf(1, 4) pg_attribute_printf(2, 4);
 
-extern int	errdetail(const char *fmt,...) pg_attribute_printf_m(1, 2);
-extern int	errdetail_internal(const char *fmt,...) pg_attribute_printf_m(1, 2);
+extern int	errdetail(const char *fmt,...) pg_attribute_printf(1, 2);
+extern int	errdetail_internal(const char *fmt,...) pg_attribute_printf(1, 2);
 
-extern int	errdetail_log(const char *fmt,...) pg_attribute_printf_m(1, 2);
+extern int	errdetail_log(const char *fmt,...) pg_attribute_printf(1, 2);
 
 extern int errdetail_log_plural(const char *fmt_singular,
 					 const char *fmt_plural,
-					 unsigned long n,...) pg_attribute_printf_m(1, 4) pg_attribute_printf_m(2, 4);
+					 unsigned long n,...) pg_attribute_printf(1, 4) pg_attribute_printf(2, 4);
 
 extern int errdetail_plural(const char *fmt_singular, const char *fmt_plural,
-				 unsigned long n,...) pg_attribute_printf_m(1, 4) pg_attribute_printf_m(2, 4);
+				 unsigned long n,...) pg_attribute_printf(1, 4) pg_attribute_printf(2, 4);
 
-extern int	errhint(const char *fmt,...) pg_attribute_printf_m(1, 2);
+extern int	errhint(const char *fmt,...) pg_attribute_printf(1, 2);
 
 /*
  * errcontext() is typically called in error context callback functions, not
@@ -184,7 +184,7 @@ extern int	errhint(const char *fmt,...) pg_attribute_printf_m(1, 2);
 
 extern int	set_errcontext_domain(const char *domain);
 
-extern int	errcontext_msg(const char *fmt,...) pg_attribute_printf_m(1, 2);
+extern int	errcontext_msg(const char *fmt,...) pg_attribute_printf(1, 2);
 
 extern int	errhidestmt(bool hide_stmt);
 extern int	errhidecontext(bool hide_ctx);
@@ -243,13 +243,13 @@ extern int	getinternalerrposition(void);
 #endif							/* HAVE__VA_ARGS */
 
 extern void elog_start(const char *filename, int lineno, const char *funcname);
-extern void elog_finish(int elevel, const char *fmt,...) pg_attribute_printf_m(2, 3);
+extern void elog_finish(int elevel, const char *fmt,...) pg_attribute_printf(2, 3);
 
 
 /* Support for constructing error strings separately from ereport() calls */
 
 extern void pre_format_elog_string(int errnumber, const char *domain);
-extern char *format_elog_string(const char *fmt,...) pg_attribute_printf_m(1, 2);
+extern char *format_elog_string(const char *fmt,...) pg_attribute_printf(1, 2);
 
 
 /* Support for attaching context information to error reports */
@@ -428,9 +428,9 @@ extern void set_syslog_parameters(const char *ident, int facility);
 #endif
 
 /*
- * Write errors to stderr (or by comparable means when stderr is not
- * available).  Used before ereport/elog can be used safely (memory context,
- * GUC load etc).  Note that this does *not* accept "%m".
+ * Write errors to stderr (or by equal means when stderr is
+ * not available). Used before ereport/elog can be used
+ * safely (memory context, GUC load etc)
  */
 extern void write_stderr(const char *fmt,...) pg_attribute_printf(1, 2);