[2/5] cpu-exec: Move exception handling out of cpu_exec()

Commit Message

[e-mail] May 10, 2016, 3:46 p.m. UTC

From: Sergey Fedorov <[e-mail]>

Simplify cpu_exec() by extracting exception handling code out of
cpu_exec() into a new static inline function cpu_handle_exception().
Also make cpu_handle_debug_exception() inline as it is used only once.

Signed-off-by: Sergey Fedorov <[e-mail]>
Signed-off-by: Sergey Fedorov <[e-mail]>
---
 cpu-exec.c | 93 +++++++++++++++++++++++++++++++++++---------------------------
 1 file changed, 52 insertions(+), 41 deletions(-)

Comments

Richard Henderson May 10, 2016, 4:21 p.m. UTC | #1

On 05/10/2016 05:46 AM, Sergey Fedorov wrote:
> From: Sergey Fedorov <[e-mail]>
>
> Simplify cpu_exec() by extracting exception handling code out of
> cpu_exec() into a new static inline function cpu_handle_exception().
> Also make cpu_handle_debug_exception() inline as it is used only once.

If it's used only once, the compiler is going to do this anyway, and therefore 
there's no point in making the change.  Let's just leave off all the inline 
markers and trust the compiler, eh?

Otherwise,

Reviewed-by: Richard Henderson <[e-mail]>


r~

Sergey Fedorov May 10, 2016, 7:21 p.m. UTC | #2

On 10/05/16 19:21, Richard Henderson wrote:
> On 05/10/2016 05:46 AM, Sergey Fedorov wrote:
>> From: Sergey Fedorov <[e-mail]>
>>
>> Simplify cpu_exec() by extracting exception handling code out of
>> cpu_exec() into a new static inline function cpu_handle_exception().
>> Also make cpu_handle_debug_exception() inline as it is used only once.
>
> If it's used only once, the compiler is going to do this anyway, and
> therefore there's no point in making the change.  Let's just leave off
> all the inline markers and trust the compiler, eh?

I agree the compiler is smart enough to decide and inline such functions
by itself. But actually, I hope such "static inline" in .c file could
indicate for a reader of the code that this function is going to be used
this way.

>
> Otherwise,
>
> Reviewed-by: Richard Henderson <[e-mail]>

Kind regards,
Sergey

Patch

diff --git a/cpu-exec.c b/cpu-exec.c
index fb72f102742c..ad95ace38dd9 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -375,7 +375,7 @@  static inline bool cpu_handle_halt(CPUState *cpu)
     return false;
 }
 
-static void cpu_handle_debug_exception(CPUState *cpu)
+static inline void cpu_handle_debug_exception(CPUState *cpu)
 {
     CPUClass *cc = CPU_GET_CLASS(cpu);
     CPUWatchpoint *wp;
@@ -389,6 +389,55 @@  static void cpu_handle_debug_exception(CPUState *cpu)
     cc->debug_excp_handler(cpu);
 }
 
+static inline bool cpu_handle_exception(CPUState *cpu, int *ret)
+{
+    if (cpu->exception_index >= 0) {
+        if (cpu->exception_index >= EXCP_INTERRUPT) {
+            /* exit request from the cpu execution loop */
+            *ret = cpu->exception_index;
+            if (*ret == EXCP_DEBUG) {
+                cpu_handle_debug_exception(cpu);
+            }
+            cpu->exception_index = -1;
+            return true;
+        } else {
+#if defined(CONFIG_USER_ONLY)
+            /* if user mode only, we simulate a fake exception
+               which will be handled outside the cpu execution
+               loop */
+#if defined(TARGET_I386)
+            CPUClass *cc = CPU_GET_CLASS(cpu);
+            cc->do_interrupt(cpu);
+#endif
+            *ret = cpu->exception_index;
+            cpu->exception_index = -1;
+            return true;
+#else
+            if (replay_exception()) {
+                CPUClass *cc = CPU_GET_CLASS(cpu);
+                cc->do_interrupt(cpu);
+                cpu->exception_index = -1;
+            } else if (!replay_has_interrupt()) {
+                /* give a chance to iothread in replay mode */
+                *ret = EXCP_INTERRUPT;
+                return true;
+            }
+#endif
+        }
+#ifndef CONFIG_USER_ONLY
+    } else if (replay_has_exception()
+               && cpu->icount_decr.u16.low + cpu->icount_extra == 0) {
+        /* try to cause an exception pending in the log */
+        TranslationBlock *last_tb = NULL; /* Avoid chaining TBs */
+        cpu_exec_nocache(cpu, 1, tb_find_fast(cpu, &last_tb, 0), true);
+        *ret = -1;
+        return true;
+#endif
+    }
+
+    return false;
+}
+
 /* main execution loop */
 
 int cpu_exec(CPUState *cpu)
@@ -426,50 +475,12 @@  int cpu_exec(CPUState *cpu)
      */
     init_delay_params(&sc, cpu);
 
-    /* prepare setjmp context for exception handling */
     for(;;) {
+        /* prepare setjmp context for exception handling */
         if (sigsetjmp(cpu->jmp_env, 0) == 0) {
             /* if an exception is pending, we execute it here */
-            if (cpu->exception_index >= 0) {
-                if (cpu->exception_index >= EXCP_INTERRUPT) {
-                    /* exit request from the cpu execution loop */
-                    ret = cpu->exception_index;
-                    if (ret == EXCP_DEBUG) {
-                        cpu_handle_debug_exception(cpu);
-                    }
-                    cpu->exception_index = -1;
-                    break;
-                } else {
-#if defined(CONFIG_USER_ONLY)
-                    /* if user mode only, we simulate a fake exception
-                       which will be handled outside the cpu execution
-                       loop */
-#if defined(TARGET_I386)
-                    cc->do_interrupt(cpu);
-#endif
-                    ret = cpu->exception_index;
-                    cpu->exception_index = -1;
-                    break;
-#else
-                    if (replay_exception()) {
-                        cc->do_interrupt(cpu);
-                        cpu->exception_index = -1;
-                    } else if (!replay_has_interrupt()) {
-                        /* give a chance to iothread in replay mode */
-                        ret = EXCP_INTERRUPT;
-                        break;
-                    }
-#endif
-                }
-#ifndef CONFIG_USER_ONLY
-            } else if (replay_has_exception()
-                       && cpu->icount_decr.u16.low + cpu->icount_extra == 0) {
-                /* try to cause an exception pending in the log */
-                last_tb = NULL; /* Avoid chaining TBs */
-                cpu_exec_nocache(cpu, 1, tb_find_fast(cpu, &last_tb, 0), true);
-                ret = -1;
+            if (cpu_handle_exception(cpu, &ret)) {
                 break;
-#endif
             }
 
             last_tb = NULL; /* forget the last executed TB after exception */