[project @ 2005-03-08 09:01:20 by simonmar]

[ghc-hetmet.git] / ghc / includes / TailCalls.h

diff --git a/ghc/includes/TailCalls.h b/ghc/includes/TailCalls.h
index 1e52be5..aa2d6f9 100644 (file)
--- a/ghc/includes/TailCalls.h
+++ b/ghc/includes/TailCalls.h
@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------------
- * $Id: TailCalls.h,v 1.11 2002/08/21 22:06:03 ken Exp $
+ * $Id: TailCalls.h,v 1.20 2005/03/08 09:01:20 simonmar Exp $
  *
  * (c) The GHC Team, 1998-1999
  *
@@ -16,7 +16,7 @@
 
 #ifdef USE_MINIINTERPRETER
 
-#define JMP_(cont) return(stgCast(StgFunPtr,cont))
+#define JMP_(cont) return((StgFunPtr)(cont))
 #define FB_
 #define FE_
 
@@ -28,7 +28,7 @@ extern void __DISCARD__(void);
    Tail calling on x86
    -------------------------------------------------------------------------- */
 
-#if i386_TARGET_ARCH
+#if i386_HOST_ARCH
 
 /* Note about discard: possibly there to fool GCC into clearing up
    before we do the jump eg. if there are some arguments left on the C
@@ -51,19 +51,56 @@ extern void __DISCARD__(void);
 
 #define JMP_(cont)                     \
     {                                  \
-      void *target;                    \
+      void *__target;                  \
       __DISCARD__();                   \
-      target = (void *)(cont);         \
-      goto *target;                    \
+      __target = (void *)(cont);       \
+      goto *__target;                  \
     }
 
-#endif /* i386_TARGET_ARCH */
+#endif /* i386_HOST_ARCH */
+
+/* -----------------------------------------------------------------------------
+   Tail calling on x86_64
+   -------------------------------------------------------------------------- */
+
+#if x86_64_HOST_ARCH
+
+/*
+  NOTE about __DISCARD__():
+
+  On x86_64 this is necessary to work around bugs in the register
+  variable support in gcc.  Without the __DISCARD__() call, gcc will
+  silently throw away assignements to global register variables that
+  happen before the jump.
+
+  Here's the example:
+
+  extern void g(void);
+  static void f(void) {
+    R1 = g;
+    __DISCARD__()
+    goto *R1;
+  }
+
+  without the dummy function call, gcc throws away the assignment to R1
+  (gcc 3.4.3) gcc bug #20359.
+*/
+
+#define JMP_(cont)                     \
+    {                                  \
+      void *__target;                  \
+      __DISCARD__();                   \
+      __target = (void *)(cont);       \
+      goto *__target;                  \
+    }
+
+#endif /* x86_64_HOST_ARCH */
 
 /* -----------------------------------------------------------------------------
    Tail calling on Sparc
    -------------------------------------------------------------------------- */
 
-#ifdef sparc_TARGET_ARCH
+#ifdef sparc_HOST_ARCH
 
 #define JMP_(cont)     ((F_) (cont))()
        /* Oh so happily, the above turns into a "call" instruction,
@@ -75,15 +112,17 @@ extern void __DISCARD__(void);
 #define FB_
 #define FE_
 
-#endif /* sparc_TARGET_ARCH */
+#endif /* sparc_HOST_ARCH */
 
 /* -----------------------------------------------------------------------------
    Tail calling on Alpha
    -------------------------------------------------------------------------- */
 
-#ifdef alpha_TARGET_ARCH
+#ifdef alpha_HOST_ARCH
 
+#if IN_STG_CODE
 register void *_procedure __asm__("$27");
+#endif
 
 #define JMP_(cont)                             \
     do { _procedure = (void *)(cont);          \
@@ -95,7 +134,7 @@ register void *_procedure __asm__("$27");
 #define FB_
 #define FE_
 
-#endif /* alpha_TARGET_ARCH */
+#endif /* alpha_HOST_ARCH */
 
 /* -----------------------------------------------------------------------------
    Tail calling on HP
@@ -156,7 +195,7 @@ but uses $$dyncall if necessary to cope, just in case you aren't.
    Tail calling on PowerPC
    -------------------------------------------------------------------------- */
 
-#ifdef powerpc_TARGET_ARCH
+#ifdef powerpc_HOST_ARCH
 
 #define JMP_(cont)                     \
     {                                  \
@@ -184,13 +223,17 @@ but uses $$dyncall if necessary to cope, just in case you aren't.
        #define JMP_(cont)      ((F_) (cont))()
 */
 
-#endif /* powerpc_TARGET_ARCH */
+#endif /* powerpc_HOST_ARCH */
+
+#ifdef powerpc64_HOST_ARCH
+#define JMP_(cont) ((F_) (cont))()
+#endif
 
 /* -----------------------------------------------------------------------------
    Tail calling on IA64
    -------------------------------------------------------------------------- */
 
-#ifdef ia64_TARGET_ARCH
+#ifdef ia64_HOST_ARCH
 
 /* The compiler can more intelligently decide how to do this.  We therefore
  * implement it as a call and optimise to a jump at mangle time. */