Add noreturn function attribute

Introduce noreturn attribute and attach it to cpu_loop_exit as well as interrupt/exception helpers for i386. This avoids a bunch of gcc4 warnings.

[ Note that this patch comes with a workaround to include qemu-common.h even in cases where is currently causes conflicts with dyngen-exec.h. I've been told that these conflicts will get resolved in the future (/me will try to have a look as well - as time permits). ]

Signed-off-by Jan Kiszka <[email protected]>

---

 cpu-all.h               |    7 ++++---
 darwin-user/signal.c    |    3 ++-
 exec-all.h              |    5 ++++-
 linux-user/signal.c     |    3 ++-
 qemu-common.h           |   14 +++++++++++---
 qemu-img.c              |    2 +-
 target-i386/exec.h      |    5 +++--
 target-i386/op_helper.c |    4 ++--
 8 files changed, 29 insertions(+), 14 deletions(-)

cpu-all.h +4 -3

index 648264c..329d26d 100644
@@ -20,6 +20,8 @@
 #ifndef CPU_ALL_H
 #define CPU_ALL_H
 
+#include "qemu-common.h"
+
 #if defined(__arm__) || defined(__sparc__) || defined(__mips__) || defined(__hppa__)
 #define WORDS_ALIGNED
 #endif

@@ -751,9 +753,8 @@ void cpu_dump_statistics (CPUState *env, FILE *f,
                           int (*cpu_fprintf)(FILE *f, const char *fmt, ...),
                           int flags);
 
-void cpu_abort(CPUState *env, const char *fmt, ...)
-    __attribute__ ((__format__ (__printf__, 2, 3)))
-    __attribute__ ((__noreturn__));
+void noreturn cpu_abort(CPUState *env, const char *fmt, ...)
+    __attribute__ ((__format__ (__printf__, 2, 3)));
 extern CPUState *first_cpu;
 extern CPUState *cpu_single_env;
 extern int64_t qemu_icount;

darwin-user/signal.c +2 -1

index f412b36..98d0894 100644
@@ -36,6 +36,7 @@
 #include <signal.h>
 
 #include "qemu.h"
+#include "qemu-common.h"
 
 #define DEBUG_SIGNAL
 

@@ -131,7 +132,7 @@ static inline void free_sigqueue(struct sigqueue *q)
 }
 
 /* abort execution with signal */
-void __attribute((noreturn)) force_sig(int sig)
+void noreturn force_sig(int sig)
 {
     int host_sig;
     host_sig = target_to_host_signal(sig);

exec-all.h +4 -1

index fd96adf..03c174c 100644
@@ -20,6 +20,9 @@
 
 #ifndef _EXEC_ALL_H_
 #define _EXEC_ALL_H_
+
+#include "qemu-common.h"
+
 /* allow to see translation results - the slowdown should be negligible, so we leave it */
 #define DEBUG_DISAS
 

@@ -82,7 +85,7 @@ TranslationBlock *tb_gen_code(CPUState *env,
                               target_ulong pc, target_ulong cs_base, int flags,
                               int cflags);
 void cpu_exec_init(CPUState *env);
-void cpu_loop_exit(void);
+void noreturn cpu_loop_exit(void);
 int page_unprotect(target_ulong address, unsigned long pc, void *puc);
 void tb_invalidate_phys_page_range(target_phys_addr_t start, target_phys_addr_t end,
                                    int is_cpu_write_access);

linux-user/signal.c +2 -1

index e0f6aaf..9d4946d 100644
@@ -27,6 +27,7 @@
 #include <sys/ucontext.h>
 
 #include "qemu.h"
+#include "qemu-common.h"
 #include "target_signal.h"
 
 //#define DEBUG_SIGNAL

@@ -325,7 +326,7 @@ static inline void free_sigqueue(CPUState *env, struct sigqueue *q)
 }
 
 /* abort execution with signal */
-static void __attribute((noreturn)) force_sig(int sig)
+static void noreturn force_sig(int sig)
 {
     int host_sig;
     host_sig = target_to_host_signal(sig);

qemu-common.h +11 -3

index d3df63e..6ee31e0 100644
@@ -2,6 +2,13 @@
 #ifndef QEMU_COMMON_H
 #define QEMU_COMMON_H
 
+#define noreturn __attribute__ ((__noreturn__))
+
+/* Hack around the mess dyngen-exec.h causes: We need noreturn in files that
+   cannot include the following headers without conflicts. This condition has
+   to be removed once dyngen is gone. */
+#ifndef __DYNGEN_EXEC_H__
+
 /* we put basic includes here to avoid repeating them in device drivers */
 #include <stdlib.h>
 #include <stdio.h>

@@ -134,9 +141,8 @@ void *get_mmap_addr(unsigned long size);
 
 /* Error handling.  */
 
-void hw_error(const char *fmt, ...)
-    __attribute__ ((__format__ (__printf__, 1, 2)))
-    __attribute__ ((__noreturn__));
+void noreturn hw_error(const char *fmt, ...)
+    __attribute__ ((__format__ (__printf__, 1, 2)));
 
 /* IO callbacks.  */
 typedef void IOReadHandler(void *opaque, const uint8_t *buf, int size);

@@ -179,4 +185,6 @@ int cpu_load(QEMUFile *f, void *opaque, int version_id);
 /* Force QEMU to stop what it's doing and service IO */
 void qemu_service_io(void);
 
+#endif /* dyngen-exec.h hack */
+
 #endif

qemu-img.c +1 -1

index 207535f..d72dd71 100644
@@ -33,7 +33,7 @@
 /* Default to cache=writeback as data integrity is not important for qemu-tcg. */
 #define BRDV_O_FLAGS BDRV_O_CACHE_WB
 
-static void __attribute__((noreturn)) error(const char *fmt, ...)
+static void noreturn error(const char *fmt, ...)
 {
     va_list ap;
     va_start(ap, fmt);

target-i386/exec.h +3 -2

index 4d97a1b..48d6102 100644
@@ -31,6 +31,7 @@
 
 register struct CPUX86State *env asm(AREG0);
 
+#include "qemu-common.h"
 #include "qemu-log.h"
 
 #define EAX (env->regs[R_EAX])

@@ -62,8 +63,8 @@ void do_interrupt(int intno, int is_int, int error_code,
                   target_ulong next_eip, int is_hw);
 void do_interrupt_user(int intno, int is_int, int error_code,
                        target_ulong next_eip);
-void raise_exception_err(int exception_index, int error_code);
-void raise_exception(int exception_index);
+void noreturn raise_exception_err(int exception_index, int error_code);
+void noreturn raise_exception(int exception_index);
 void do_smm_enter(void);
 
 /* n must be a constant to be efficient */

target-i386/op_helper.c +0 -0

index 52fee3d..d50a9c0 100644

Quoted 199 lines · Jan Kiszka

Introduce noreturn attribute and attach it to cpu_loop_exit as well as interrupt/exception helpers for i386. This avoids a bunch of gcc4 warnings.

[ Note that this patch comes with a workaround to include qemu-common.h even in cases where is currently causes conflicts with dyngen-exec.h. I've been told that these conflicts will get resolved in the future (/me will try to have a look as well - as time permits). ]

Signed-off-by Jan Kiszka <[email protected]>

---

 cpu-all.h               |    7 ++++---
 darwin-user/signal.c    |    3 ++-
 exec-all.h              |    5 ++++-
 linux-user/signal.c     |    3 ++-
 qemu-common.h           |   14 +++++++++++---
 qemu-img.c              |    2 +-
 target-i386/exec.h      |    5 +++--
 target-i386/op_helper.c |    4 ++--
 8 files changed, 29 insertions(+), 14 deletions(-)

cpu-all.h +4 -3

index 648264c..329d26d 100644
@@ -20,6 +20,8 @@
 #ifndef CPU_ALL_H
 #define CPU_ALL_H
 
+#include "qemu-common.h"
+
 #if defined(__arm__) || defined(__sparc__) || defined(__mips__) || defined(__hppa__)
 #define WORDS_ALIGNED
 #endif

@@ -751,9 +753,8 @@ void cpu_dump_statistics (CPUState *env, FILE *f,
                           int (*cpu_fprintf)(FILE *f, const char *fmt, ...),
                           int flags);
 
-void cpu_abort(CPUState *env, const char *fmt, ...)
-    __attribute__ ((__format__ (__printf__, 2, 3)))
-    __attribute__ ((__noreturn__));
+void noreturn cpu_abort(CPUState *env, const char *fmt, ...)
+    __attribute__ ((__format__ (__printf__, 2, 3)));
 extern CPUState *first_cpu;
 extern CPUState *cpu_single_env;
 extern int64_t qemu_icount;

darwin-user/signal.c +2 -1

index f412b36..98d0894 100644
@@ -36,6 +36,7 @@
 #include <signal.h>
 
 #include "qemu.h"
+#include "qemu-common.h"
 
 #define DEBUG_SIGNAL
 

@@ -131,7 +132,7 @@ static inline void free_sigqueue(struct sigqueue *q)
 }
 
 /* abort execution with signal */
-void __attribute((noreturn)) force_sig(int sig)
+void noreturn force_sig(int sig)
 {
     int host_sig;
     host_sig = target_to_host_signal(sig);

exec-all.h +4 -1

index fd96adf..03c174c 100644
@@ -20,6 +20,9 @@
 
 #ifndef _EXEC_ALL_H_
 #define _EXEC_ALL_H_
+
+#include "qemu-common.h"
+
 /* allow to see translation results - the slowdown should be negligible, so we leave it */
 #define DEBUG_DISAS
 

@@ -82,7 +85,7 @@ TranslationBlock *tb_gen_code(CPUState *env,
                               target_ulong pc, target_ulong cs_base, int flags,
                               int cflags);
 void cpu_exec_init(CPUState *env);
-void cpu_loop_exit(void);
+void noreturn cpu_loop_exit(void);
 int page_unprotect(target_ulong address, unsigned long pc, void *puc);
 void tb_invalidate_phys_page_range(target_phys_addr_t start, target_phys_addr_t end,
                                    int is_cpu_write_access);

linux-user/signal.c +2 -1

index e0f6aaf..9d4946d 100644
@@ -27,6 +27,7 @@
 #include <sys/ucontext.h>
 
 #include "qemu.h"
+#include "qemu-common.h"
 #include "target_signal.h"
 
 //#define DEBUG_SIGNAL

@@ -325,7 +326,7 @@ static inline void free_sigqueue(CPUState *env, struct sigqueue *q)
 }
 
 /* abort execution with signal */
-static void __attribute((noreturn)) force_sig(int sig)
+static void noreturn force_sig(int sig)
 {
     int host_sig;
     host_sig = target_to_host_signal(sig);

qemu-common.h +11 -3

index d3df63e..6ee31e0 100644
@@ -2,6 +2,13 @@
 #ifndef QEMU_COMMON_H
 #define QEMU_COMMON_H
 
+#define noreturn __attribute__ ((__noreturn__))
+
+/* Hack around the mess dyngen-exec.h causes: We need noreturn in files that
+   cannot include the following headers without conflicts. This condition has
+   to be removed once dyngen is gone. */
+#ifndef __DYNGEN_EXEC_H__
+
 /* we put basic includes here to avoid repeating them in device drivers */
 #include <stdlib.h>
 #include <stdio.h>

@@ -134,9 +141,8 @@ void *get_mmap_addr(unsigned long size);
 
 /* Error handling.  */
 
-void hw_error(const char *fmt, ...)
-    __attribute__ ((__format__ (__printf__, 1, 2)))
-    __attribute__ ((__noreturn__));
+void noreturn hw_error(const char *fmt, ...)
+    __attribute__ ((__format__ (__printf__, 1, 2)));
 
 /* IO callbacks.  */
 typedef void IOReadHandler(void *opaque, const uint8_t *buf, int size);

@@ -179,4 +185,6 @@ int cpu_load(QEMUFile *f, void *opaque, int version_id);
 /* Force QEMU to stop what it's doing and service IO */
 void qemu_service_io(void);
 
+#endif /* dyngen-exec.h hack */
+
 #endif

qemu-img.c +1 -1

index 207535f..d72dd71 100644
@@ -33,7 +33,7 @@
 /* Default to cache=writeback as data integrity is not important for qemu-tcg. */
 #define BRDV_O_FLAGS BDRV_O_CACHE_WB
 
-static void __attribute__((noreturn)) error(const char *fmt, ...)
+static void noreturn error(const char *fmt, ...)
 {
     va_list ap;
     va_start(ap, fmt);

target-i386/exec.h +3 -2

index 4d97a1b..48d6102 100644
@@ -31,6 +31,7 @@
 
 register struct CPUX86State *env asm(AREG0);
 
+#include "qemu-common.h"
 #include "qemu-log.h"
 
 #define EAX (env->regs[R_EAX])

@@ -62,8 +63,8 @@ void do_interrupt(int intno, int is_int, int error_code,
                   target_ulong next_eip, int is_hw);
 void do_interrupt_user(int intno, int is_int, int error_code,
                        target_ulong next_eip);
-void raise_exception_err(int exception_index, int error_code);
-void raise_exception(int exception_index);
+void noreturn raise_exception_err(int exception_index, int error_code);
+void noreturn raise_exception(int exception_index);
 void do_smm_enter(void);
 
 /* n must be a constant to be efficient */

target-i386/op_helper.c +2 -2

index 52fee3d..d50a9c0 100644
@@ -1284,8 +1284,8 @@ static int check_exception(int intno, int *error_code)
  * EIP value AFTER the interrupt instruction. It is only relevant if
  * is_int is TRUE.
  */
-static void raise_interrupt(int intno, int is_int, int error_code,
-                            int next_eip_addend)
+static void noreturn raise_interrupt(int intno, int is_int, int error_code,
+                                     int next_eip_addend)
 {
     if (!is_int) {

target-i386/op_helper.c static int check_exception(int intno, int *error_code) · line 1291

Quoted 4 lines

target-i386/op_helper.c +0 -0

         helper_svm_check_intercept_param(SVM_EXIT_EXCP_BASE + intno, error_code);

Any comment on this? It still applies - and it still kills a lot of
compiler warnings.