[Qemu-devel] [PATCH 08/15] Avoid declaring the env variable at all if CONFIG_TCG_PASS_AREG0.

[Richard Henderson]

Signed-off-by: Richard Henderson <address@hidden>
---
 dyngen-exec.h |    5 +++++
 user-exec.c   |   17 ++++++++++++++---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/dyngen-exec.h b/dyngen-exec.h
index cfeef99..65fcb43 100644
--- a/dyngen-exec.h
+++ b/dyngen-exec.h
@@ -19,6 +19,10 @@
 #if !defined(__DYNGEN_EXEC_H__)
 #define __DYNGEN_EXEC_H__
 
+/* If the target has indicated that it does not need an AREG0,
+   don't declare the env variable at all, much less as a register.  */
+#if !defined(CONFIG_TCG_PASS_AREG0)
+
 #if defined(CONFIG_TCG_INTERPRETER)
 /* The TCG interpreter does not need a special register AREG0,
  * but it is possible to use one by defining AREG0.
@@ -65,4 +69,5 @@ register CPUArchState *env asm(AREG0);
 extern CPUArchState *env;
 #endif
 
+#endif /* !CONFIG_TCG_PASS_AREG0 */
 #endif /* !defined(__DYNGEN_EXEC_H__) */
diff --git a/user-exec.c b/user-exec.c
index cd905ff..e326104 100644
--- a/user-exec.c
+++ b/user-exec.c
@@ -58,7 +58,9 @@ void cpu_resume_from_signal(CPUArchState *env1, void *puc)
     struct sigcontext *uc = puc;
 #endif
 
+#ifndef CONFIG_TCG_PASS_AREG0
     env = env1;
+#endif
 
     /* XXX: restore cpu registers saved in host registers */
 
@@ -74,8 +76,8 @@ void cpu_resume_from_signal(CPUArchState *env1, void *puc)
         sigprocmask(SIG_SETMASK, &uc->sc_mask, NULL);
 #endif
     }
-    env->exception_index = -1;
-    longjmp(env->jmp_env, 1);
+    env1->exception_index = -1;
+    longjmp(env1->jmp_env, 1);
 }
 
 /* 'pc' is the host PC at which the exception was raised. 'address' is
@@ -89,9 +91,18 @@ static inline int handle_cpu_signal(unsigned long pc, 
unsigned long address,
     TranslationBlock *tb;
     int ret;
 
+    /* XXX: find a correct solution for multithread */
+#ifdef CONFIG_TCG_PASS_AREG0
+    /* ??? While we no longer have a global env register, if PC is within
+       the code_gen_buffer then we know that env is within a known register
+       there, and we could have the signal handler extract that value.  */
+    CPUArchState *env = cpu_single_env;
+#else
     if (cpu_single_env) {
-        env = cpu_single_env; /* XXX: find a correct solution for multithread 
*/
+        env = cpu_single_env;
     }
+#endif
+
 #if defined(DEBUG_SIGNAL)
     qemu_printf("qemu: SIGSEGV pc=0x%08lx address=%08lx w=%d oldset=0x%08lx\n",
                 pc, address, is_write, *(unsigned long *)old_set);
-- 
1.7.7.6