X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Frts%2FMBlock.h;h=c369416ff4a733c1a8bc4f3e0dec52aa1a51689f;hb=9bb32dd2adae0a71b558b366bb73c4d4771ef80a;hp=75ead18f60a573c7e7757a90a1c00e79b3b3f83d;hpb=9ac55e08e159d7a4647ab01e7872e69dd762f275;p=ghc-hetmet.git

diff --git a/ghc/rts/MBlock.h b/ghc/rts/MBlock.h
index 75ead18..c369416 100644
--- a/ghc/rts/MBlock.h
+++ b/ghc/rts/MBlock.h
@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------------
- * $Id: MBlock.h,v 1.7 2000/12/04 12:31:21 simonmar Exp $
+ * $Id: MBlock.h,v 1.16 2002/11/22 06:54:05 matthewc Exp $
  *
  * (c) The GHC Team, 1998-1999
  *
@@ -7,50 +7,76 @@
  *
  * ---------------------------------------------------------------------------*/
 
+#ifndef __MBLOCK_H__
+#define __MBLOCK_H__
 extern lnat mblocks_allocated;
 
-#ifdef ENABLE_WIN32_DLL_SUPPORT
-extern int is_heap_alloced(const void* p);
-#endif
-
 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
-/* guess */
-#define HEAP_BASE 0x50000000
-
-#elif hpux_TARGET_OS
-/* guess */
-#define HEAP_BASE 0x50000000
-
-#elif _WIN32
-/* doesn't matter, we use a reserve/commit algorithm */
+#if osf3_TARGET_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
+#define HEAP_BASE 0x180000000L
+#else
+#error I have no idea where to begin the heap on a non-64-bit osf3 machine.
+#endif
 
 #else
-#error Dont know where to get memory from on this architecture
-/* ToDo: memory locations on other architectures */
+
+// 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
+   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+   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).
+   -------------------------------------------------------------------------- */
+
+extern StgWord8 mblock_map[];
+
+#if SIZEOF_VOID_P == 4
+/* 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)]
+# define MARK_HEAP_ALLOCED(p)	(mblock_map[MBLOCK_MAP_ENTRY(p)] = 1)
+
+#elif defined(ia64_TARGET_ARCH)
+/* Instead of trying to cover the whole 64-bit address space (which would
+ * require a better data structure), we assume that mmap allocates mappings
+ * from the bottom of region 1, and track some portion of address space from
+ * there upwards (currently 4GB). */
+# define MBLOCK_MAP_SIZE	4096
+# define MBLOCK_MAP_ENTRY(p)	(((StgWord)(p) - (1UL << 61)) >> MBLOCK_SHIFT)
+# define HEAP_ALLOCED(p)	((MBLOCK_MAP_ENTRY(p) < MBLOCK_MAP_SIZE) \
+					&& mblock_map[MBLOCK_MAP_ENTRY(p)])
+# define MARK_HEAP_ALLOCED(p)	((MBLOCK_MAP_ENTRY(p) < MBLOCK_MAP_SIZE) \
+					&& (mblock_map[MBLOCK_MAP_ENTRY(p)] = 1))
+
+#elif defined(TEXT_BEFORE_HEAP)
+/* Fall back to old method - assume heap above HEAP_BASE */
+# define HEAP_ALLOCED(p)	((StgPtr)(p) >= (StgPtr)(HEAP_BASE))
+# define MARK_HEAP_ALLOCED(p)	do {} while(0)
+
+#else
+# error HEAP_ALLOCED not defined
+#endif
+
+#endif // __MBLOCK_H__