Add macros wrapping all usage of gcc's __attribute__.

Until now __attribute__() was defined to be empty for all compilers but
gcc. That's problematic because it prevents using it in other compilers;
which is necessary e.g. for atomics portability.  It's also just
generally dubious to do so in a header as widely included as c.h.

Instead add pg_attribute_format_arg, pg_attribute_printf,
pg_attribute_noreturn macros which are implemented in the compilers that
understand them. Also add pg_attribute_noreturn and pg_attribute_packed,
but don't provide fallbacks, since they can affect functionality.

This means that external code that, possibly unwittingly, relied on
__attribute__ defined to be empty on !gcc compilers may now run into
warnings or errors on those compilers. But there shouldn't be many
occurances of that and it's hard to work around...

Discussion: 54B58BA3.8040302@ohmu.fi
Author: Oskari Saarenmaa, with some minor changes by me.

8 files changed, 11 insertions, 11 deletions

diff --git a/src/include/postmaster/autovacuum.h b/src/include/postmaster/autovacuum.h
index 121f107387..0bd50443ae 100644
--- a/src/include/postmaster/autovacuum.h
+++ b/src/include/postmaster/autovacuum.h
@@ -54,8 +54,8 @@ extern void AutoVacWorkerFailed(void);
 extern void AutoVacuumUpdateDelay(void);
 
 #ifdef EXEC_BACKEND
-extern void AutoVacLauncherMain(int argc, char *argv[]) __attribute__((noreturn));
-extern void AutoVacWorkerMain(int argc, char *argv[]) __attribute__((noreturn));
+extern void AutoVacLauncherMain(int argc, char *argv[]) pg_attribute_noreturn;
+extern void AutoVacWorkerMain(int argc, char *argv[]) pg_attribute_noreturn;
 extern void AutovacuumWorkerIAm(void);
 extern void AutovacuumLauncherIAm(void);
 #endif
diff --git a/src/include/postmaster/bgworker_internals.h b/src/include/postmaster/bgworker_internals.h
index 81c03e4bb3..fe7c328afd 100644
--- a/src/include/postmaster/bgworker_internals.h
+++ b/src/include/postmaster/bgworker_internals.h
@@ -46,7 +46,7 @@ extern void BackgroundWorkerStopNotifications(pid_t pid);
 extern void ResetBackgroundWorkerCrashTimes(void);
 
 /* Function to start a background worker, called from postmaster.c */
-extern void StartBackgroundWorker(void) __attribute__((noreturn));
+extern void StartBackgroundWorker(void) pg_attribute_noreturn;
 
 #ifdef EXEC_BACKEND
 extern BackgroundWorker *BackgroundWorkerEntry(int slotno);
diff --git a/src/include/postmaster/bgwriter.h b/src/include/postmaster/bgwriter.h
index ce12619797..f584d85787 100644
--- a/src/include/postmaster/bgwriter.h
+++ b/src/include/postmaster/bgwriter.h
@@ -25,8 +25,8 @@ extern int	CheckPointTimeout;
 extern int	CheckPointWarning;
 extern double CheckPointCompletionTarget;
 
-extern void BackgroundWriterMain(void) __attribute__((noreturn));
-extern void CheckpointerMain(void) __attribute__((noreturn));
+extern void BackgroundWriterMain(void) pg_attribute_noreturn;
+extern void CheckpointerMain(void) pg_attribute_noreturn;
 
 extern void RequestCheckpoint(int flags);
 extern void CheckpointWriteDelay(int flags, double progress);
diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h
index a585e6736c..60e4f50368 100644
--- a/src/include/postmaster/pgarch.h
+++ b/src/include/postmaster/pgarch.h
@@ -33,7 +33,7 @@
 extern int	pgarch_start(void);
 
 #ifdef EXEC_BACKEND
-extern void PgArchiverMain(int argc, char *argv[]) __attribute__((noreturn));
+extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn;
 #endif
 
 #endif   /* _PGARCH_H */
diff --git a/src/include/postmaster/postmaster.h b/src/include/postmaster/postmaster.h
index 91723f7d9a..d41761fc7a 100644
--- a/src/include/postmaster/postmaster.h
+++ b/src/include/postmaster/postmaster.h
@@ -46,7 +46,7 @@ extern int	postmaster_alive_fds[2];
 
 extern const char *progname;
 
-extern void PostmasterMain(int argc, char *argv[]) __attribute__((noreturn));
+extern void PostmasterMain(int argc, char *argv[]) pg_attribute_noreturn;
 extern void ClosePostmasterPorts(bool am_syslogger);
 
 extern int	MaxLivePostmasterChildren(void);
@@ -56,7 +56,7 @@ extern bool PostmasterMarkPIDForWorkerNotify(int);
 
 #ifdef EXEC_BACKEND
 extern pid_t postmaster_forkexec(int argc, char *argv[]);
-extern void SubPostmasterMain(int argc, char *argv[]) __attribute__((noreturn));
+extern void SubPostmasterMain(int argc, char *argv[]) pg_attribute_noreturn;
 
 extern Size ShmemBackendArraySize(void);
 extern void ShmemBackendArrayAllocation(void);
diff --git a/src/include/postmaster/startup.h b/src/include/postmaster/startup.h
index da1f6e9336..9a2092e5f2 100644
--- a/src/include/postmaster/startup.h
+++ b/src/include/postmaster/startup.h
@@ -13,7 +13,7 @@
 #define _STARTUP_H
 
 extern void HandleStartupProcInterrupts(void);
-extern void StartupProcessMain(void) __attribute__((noreturn));
+extern void StartupProcessMain(void) pg_attribute_noreturn;
 extern void PreRestoreCommand(void);
 extern void PostRestoreCommand(void);
 extern bool IsPromoteTriggered(void);
diff --git a/src/include/postmaster/syslogger.h b/src/include/postmaster/syslogger.h
index 89a535c18f..d6a05d5a20 100644
--- a/src/include/postmaster/syslogger.h
+++ b/src/include/postmaster/syslogger.h
@@ -84,7 +84,7 @@ extern int	SysLogger_Start(void);
 extern void write_syslogger_file(const char *buffer, int count, int dest);
 
 #ifdef EXEC_BACKEND
-extern void SysLoggerMain(int argc, char *argv[]) __attribute__((noreturn));
+extern void SysLoggerMain(int argc, char *argv[]) pg_attribute_noreturn;
 #endif
 
 #endif   /* _SYSLOGGER_H */
diff --git a/src/include/postmaster/walwriter.h b/src/include/postmaster/walwriter.h
index de45a01f82..55de6c73e4 100644
--- a/src/include/postmaster/walwriter.h
+++ b/src/include/postmaster/walwriter.h
@@ -15,6 +15,6 @@
 /* GUC options */
 extern int	WalWriterDelay;
 
-extern void WalWriterMain(void) __attribute__((noreturn));
+extern void WalWriterMain(void) pg_attribute_noreturn;
 
 #endif   /* _WALWRITER_H */