[commit: ghc] master: Remove most of TailCalls.h (2b977d9)

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/2b977d98a0f15416721633f14f9f551ce9ad30f0

>---------------------------------------------------------------

commit 2b977d98a0f15416721633f14f9f551ce9ad30f0
Author: Simon Marlow <[email protected]>
Date:   Tue Dec 11 16:53:24 2012 +0000

    Remove most of TailCalls.h
    
    it was only needed for registerised compilation.

>---------------------------------------------------------------

 includes/Stg.h           |    7 +-
 includes/stg/TailCalls.h |  185 ----------------------------------------------
 2 files changed, 3 insertions(+), 189 deletions(-)

diff --git a/includes/Stg.h b/includes/Stg.h
index ba0c4cf..c451cbc 100644
--- a/includes/Stg.h
+++ b/includes/Stg.h
@@ -217,12 +217,11 @@ typedef StgFunPtr       F_;
 
 /* -----------------------------------------------------------------------------
    Tail calls
-
-   This needs to be up near the top as the register line on alpha needs
-   to be before all procedures (inline & out-of-line).
    -------------------------------------------------------------------------- */
 
-#include "stg/TailCalls.h"
+#define JMP_(cont) return((StgFunPtr)(cont))
+#define FB_
+#define FE_
 
 /* -----------------------------------------------------------------------------
    Other Stg stuff...
diff --git a/includes/stg/TailCalls.h b/includes/stg/TailCalls.h
deleted file mode 100644
index 77ceb0c..0000000
--- a/includes/stg/TailCalls.h
+++ /dev/null
@@ -1,185 +0,0 @@
-/* -----------------------------------------------------------------------------
- *
- * (c) The GHC Team, 1998-2009
- *
- * Stuff for implementing proper tail jumps.
- *
- * Do not #include this file directly: #include "Rts.h" instead.
- *
- * To understand the structure of the RTS headers, see the wiki:
- *   http://hackage.haskell.org/trac/ghc/wiki/Commentary/SourceTree/Includes
- *
- * ---------------------------------------------------------------------------*/
-
-#ifndef TAILCALLS_H
-#define TAILCALLS_H
-
-/* -----------------------------------------------------------------------------
-   Unmangled tail-jumping: use the mini interpretter.
-   -------------------------------------------------------------------------- */
-
-#ifdef USE_MINIINTERPRETER
-
-#define JMP_(cont) return((StgFunPtr)(cont))
-#define FB_
-#define FE_
-
-#else
-
-extern void __DISCARD__(void);
-
-/* -----------------------------------------------------------------------------
-   Tail calling on x86
-   -------------------------------------------------------------------------- */
-
-#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
-   stack that GCC hasn't popped yet.  Also possibly to fool any
-   optimisations (a function call often acts as a barrier).  Not sure
-   if any of this is necessary now -- SDM
-
-   Comment to above note: I don't think the __DISCARD__() in JMP_ is 
-   necessary.  Arguments should be popped from the C stack immediately
-   after returning from a function, as long as we pass -fno-defer-pop
-   to gcc.  Moreover, a goto to a first-class label acts as a barrier 
-   for optimisations in the same way a function call does. 
-   -= chak
-   */
-
-/* The goto here seems to cause gcc -O2 to delete all the code after
-   it - including the FE_ marker and the epilogue code - exactly what
-   we want! -- SDM
-   */
-
-#define JMP_(cont)			\
-    { 					\
-      void *__target;			\
-      __DISCARD__();			\
-      __target = (void *)(cont);    	\
-      goto *__target; 	    	    	\
-    }
-
-#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)			\
-    { 					\
-      __DISCARD__();			\
-      goto *(void *)(cont); 	    	    	\
-    }
-
-#endif /* x86_64_HOST_ARCH */
-
-/* -----------------------------------------------------------------------------
-   Tail calling on Sparc
-   -------------------------------------------------------------------------- */
-
-#ifdef sparc_HOST_ARCH
-
-#define JMP_(cont)	((F_) (cont))()
-	/* Oh so happily, the above turns into a "call" instruction,
-	   which, on a SPARC, is nothing but a "jmpl" with the
-	   return address in %o7 [which we don't care about].
-	*/
-
-/* Don't need these for sparc mangling */
-#define FB_
-#define FE_
-
-#endif /* sparc_HOST_ARCH */
-
-/* -----------------------------------------------------------------------------
-   Tail calling on PowerPC
-   -------------------------------------------------------------------------- */
-
-#ifdef powerpc_HOST_ARCH
-
-#define JMP_(cont)			\
-    { 					\
-      void *target;			\
-      target = (void *)(cont);    	\
-      __DISCARD__();			\
-      goto *target; 	    	    	\
-    }
-
-/*
-	The __DISCARD__ is there because Apple's April 2002 Beta of GCC 3.1
-	sometimes generates incorrect code otherwise.
-	It tends to "forget" to update global register variables in the presence
-	of decrement/increment operators:
-	JMP_(*(--Sp)) is wrongly compiled as JMP_(Sp[-1]).
-	Calling __DISCARD__ in between works around this problem.
-*/
-
-/*
-	I would _love_ to use the following instead,
-	but some versions of Apple's GCC fail to generate code for it
-	if it is called for a casted data pointer - which is exactly what
-	we are going to do...
-
-	#define JMP_(cont)	((F_) (cont))()
-*/
-
-#endif /* powerpc_HOST_ARCH */
-
-#ifdef powerpc64_HOST_ARCH
-#define JMP_(cont) ((F_) (cont))()
-#endif
-
-/* -----------------------------------------------------------------------------
-  FUNBEGIN and FUNEND.
-
-  These are markers indicating the start and end of Real Code in a
-  function.  All instructions between the actual start and end of the
-  function and these markers is shredded by the mangler.
-  -------------------------------------------------------------------------- */
-
-/*  The following __DISCARD__() has become necessary with gcc 2.96 on x86.
- *  It prevents gcc from moving stack manipulation code from the function
- *  body (aka the Real Code) into the function prologue, ie, from moving it
- *  over the --- BEGIN --- marker.  It should be noted that (like some
- *  other black magic in GHC's code), there is no essential reason why gcc
- *  could not move some stack manipulation code across the __DISCARD__() -
- *  it just doesn't choose to do it at the moment.
- *  -= chak
- */
- 
-#ifndef FB_
-#define FB_    __asm__ volatile ("--- BEGIN ---"); __DISCARD__ ();
-#endif
-
-#ifndef FE_
-#define FE_    __asm__ volatile ("--- END ---");
-#endif
-
-#endif /* !USE_MINIINTERPRETER */
-
-#endif /* TAILCALLS_H */