X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Frts%2FMBlock.h;h=d3214c8311a022778950ec688d7ed42fed984895;hb=03a9ff01812afc81eb5236fd3063cbec44cf469e;hp=8ca6c5115c158d7859a8a081d0280d5cd272430d;hpb=5ca4a0134475bbc790af6ce7d7517a97e877bff6;p=ghc-hetmet.git

diff --git a/ghc/rts/MBlock.h b/ghc/rts/MBlock.h
index 8ca6c51..d3214c8 100644
--- a/ghc/rts/MBlock.h
+++ b/ghc/rts/MBlock.h
@@ -1,45 +1,20 @@
 /* -----------------------------------------------------------------------------
- * $Id: MBlock.h,v 1.11 2001/12/10 01:28:00 sebc Exp $
  *
- * (c) The GHC Team, 1998-1999
+ * (c) The GHC Team, 1998-2005
  *
  * MegaBlock Allocator interface.
  *
  * ---------------------------------------------------------------------------*/
 
-extern lnat mblocks_allocated;
+#ifndef MBLOCK_H
+#define MBLOCK_H
 
-#ifdef ENABLE_WIN32_DLL_SUPPORT
-extern int is_heap_alloced(const void* p);
-#endif
+extern lnat RTS_VAR(mblocks_allocated);
 
 extern void * getMBlock(void);
 extern void * getMBlocks(nat n);
 
-#if freebsd2_TARGET_OS || freebsd_TARGET_OS
-/* Executable is loaded from      0x0
- * Shared libraries are loaded at 0x2000000
- * Stack is at the top of the address space.  The kernel probably owns
- * 0x8000000 onwards, so we'll pick 0x5000000.
- */
-#define HEAP_BASE 0x50000000
-
-#elif netbsd_TARGET_OS
-/* NetBSD i386 shared libs are at 0x40000000
- */
-#define HEAP_BASE 0x50000000
-#elif openbsd_TARGET_OS
-#define HEAP_BASE 0x50000000
-#elif linux_TARGET_OS
-/* Any ideas?
- */
-#define HEAP_BASE 0x50000000
-
-#elif solaris2_TARGET_OS
-/* guess */
-#define HEAP_BASE 0x50000000
-
-#elif osf3_TARGET_OS
+#if osf3_HOST_OS
 /* ToDo: Perhaps by adjusting this value we can make linking without
  * -static work (i.e., not generate a core-dumping executable)? */
 #if SIZEOF_VOID_P == 8
@@ -48,18 +23,67 @@ extern void * getMBlocks(nat n);
 #error I have no idea where to begin the heap on a non-64-bit osf3 machine.
 #endif
 
-#elif hpux_TARGET_OS
-/* guess */
-#define HEAP_BASE 0x50000000
+#else
+
+// we're using the generic method
+#define HEAP_BASE 0
+
+#endif
+
+/* -----------------------------------------------------------------------------
+   The HEAP_ALLOCED() test.
+
+   HEAP_ALLOCED is called FOR EVERY SINGLE CLOSURE during GC.
+   It needs to be FAST.
+
+   Implementation of HEAP_ALLOCED
+   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-#elif darwin_TARGET_OS
-/* guess */
-#define HEAP_BASE 0x50000000
+   Since heap is allocated in chunks of megablocks (MBLOCK_SIZE), we
+   can just use a table to record which megablocks in the address
+   space belong to the heap.  On a 32-bit machine, with 1Mb
+   megablocks, using 8 bits for each entry in the table, the table
+   requires 4k.  Lookups during GC will be fast, because the table
+   will be quickly cached (indeed, performance measurements showed no
+   measurable difference between doing the table lookup and using a
+   constant comparison).
 
-#elif defined(mingw32_TARGET_OS) || defined(cygwin32_TARGET_OS)
-/* doesn't matter, we use a reserve/commit algorithm */
+   On 64-bit machines, we cache one 12-bit block map that describes
+   4096 megablocks or 4GB of memory. If HEAP_ALLOCED is called for
+   an address that is not in the cache, it calls slowIsHeapAlloced
+   (see MBlock.c) which will find the block map for the 4GB block in
+   question.
+   -------------------------------------------------------------------------- */
+
+#if SIZEOF_VOID_P == 4
+extern StgWord8 mblock_map[];
+
+/* On a 32-bit machine a 4KB table is always sufficient */
+# define MBLOCK_MAP_SIZE	4096
+# define MBLOCK_MAP_ENTRY(p)	((StgWord)(p) >> MBLOCK_SHIFT)
+# define HEAP_ALLOCED(p)	mblock_map[MBLOCK_MAP_ENTRY(p)]
+
+#elif SIZEOF_VOID_P == 8
+
+# define MBLOCK_MAP_SIZE	4096
+# define MBLOCK_MAP_ENTRY(p)	(((StgWord)(p) & 0xffffffff) >> MBLOCK_SHIFT)
+
+typedef struct {
+    StgWord32	addrHigh32;
+    StgWord8	mblocks[MBLOCK_MAP_SIZE];
+} MBlockMap;
+
+extern MBlockMap *mblock_cache;
+
+StgBool slowIsHeapAlloced(void *p);
+
+# define HEAP_ALLOCED(p)  					\
+	( ((((StgWord)(p)) >> 32) == mblock_cache->addrHigh32)	\
+	? mblock_cache->mblocks[MBLOCK_MAP_ENTRY(p)]		\
+	: slowIsHeapAlloced(p) )
 
 #else
-#error Dont know where to get memory from on this architecture
-/* ToDo: memory locations on other architectures */
+# error HEAP_ALLOCED not defined
 #endif
+
+#endif /* MBLOCK_H */