more complete pseudo-fork() support for Windows

p4raw-id: //depot/perl@4602

1 files changed, 703 insertions, 0 deletions

diff --git a/win32/vmem.h b/win32/vmem.h
new file mode 100644
index 0000000000..cf3f502ca0
--- /dev/null
+++ b/win32/vmem.h
@@ -0,0 +1,703 @@
+/* vmem.h
+ *
+ * (c) 1999 Microsoft Corporation. All rights reserved. 
+ * Portions (c) 1999 ActiveState Tool Corp, http://www.ActiveState.com/
+ *
+ *    You may distribute under the terms of either the GNU General Public
+ *    License or the Artistic License, as specified in the README file.
+ *
+ *
+ * Knuth's boundary tag algorithm Vol #1, Page 440.
+ *
+ * Each block in the heap has tag words before and after it,
+ *  TAG
+ *  block
+ *  TAG
+ * The size is stored in these tags as a long word, and includes the 8 bytes
+ * of overhead that the boundary tags consume.  Blocks are allocated on long
+ * word boundaries, so the size is always multiples of long words.  When the
+ * block is allocated, bit 0, (the tag bit), of the size is set to 1.  When 
+ * a block is freed, it is merged with adjacent free blocks, and the tag bit
+ * is set to 0.
+ *
+ * A linked list is used to manage the free list. The first two long words of
+ * the block contain double links.  These links are only valid when the block
+ * is freed, therefore space needs to be reserved for them.  Thus, the minimum
+ * block size (not counting the tags) is 8 bytes.
+ *
+ * Since memory allocation may occur on a single threaded, explict locks are
+ * provided.
+ * 
+ */
+
+#ifndef ___VMEM_H_INC___
+#define ___VMEM_H_INC___
+
+const long lAllocStart = 0x00010000; /* start at 64K */
+const long minBlockSize = sizeof(void*)*2;
+const long sizeofTag = sizeof(long);
+const long blockOverhead = sizeofTag*2;
+const long minAllocSize = minBlockSize+blockOverhead;
+
+typedef BYTE* PBLOCK;	/* pointer to a memory block */
+
+/*
+ * Macros for accessing hidden fields in a memory block:
+ *
+ * SIZE	    size of this block (tag bit 0 is 1 if block is allocated)
+ * PSIZE    size of previous physical block
+ */
+
+#define SIZE(block)	(*(ULONG*)(((PBLOCK)(block))-sizeofTag))
+#define PSIZE(block)	(*(ULONG*)(((PBLOCK)(block))-(sizeofTag*2)))
+inline void SetTags(PBLOCK block, long size)
+{
+    SIZE(block) = size;
+    PSIZE(block+(size&~1)) = size;
+}
+
+/*
+ * Free list pointers
+ * PREV	pointer to previous block
+ * NEXT	pointer to next block
+ */
+
+#define PREV(block)	(*(PBLOCK*)(block))
+#define NEXT(block)	(*(PBLOCK*)((block)+sizeof(PBLOCK)))
+inline void SetLink(PBLOCK block, PBLOCK prev, PBLOCK next)
+{
+    PREV(block) = prev;
+    NEXT(block) = next;
+}
+inline void Unlink(PBLOCK p)
+{
+    PBLOCK next = NEXT(p);
+    PBLOCK prev = PREV(p);
+    NEXT(prev) = next;
+    PREV(next) = prev;
+}
+inline void AddToFreeList(PBLOCK block, PBLOCK pInList)
+{
+    PBLOCK next = NEXT(pInList);
+    NEXT(pInList) = block;
+    SetLink(block, pInList, next);
+    PREV(next) = block;
+}
+
+
+/* Macro for rounding up to the next sizeof(long) */
+#define ROUND_UP(n)	(((ULONG)(n)+sizeof(long)-1)&~(sizeof(long)-1))
+#define ROUND_UP64K(n)	(((ULONG)(n)+0x10000-1)&~(0x10000-1))
+#define ROUND_DOWN(n)	((ULONG)(n)&~(sizeof(long)-1))
+
+/*
+ * HeapRec - a list of all non-contiguous heap areas
+ *
+ * Each record in this array contains information about a non-contiguous heap area.
+ */
+
+const int maxHeaps = 64;
+const long lAllocMax   = 0x80000000; /* max size of allocation */
+
+typedef struct _HeapRec
+{
+    PBLOCK	base;	/* base of heap area */
+    ULONG	len;	/* size of heap area */
+} HeapRec;
+
+
+class VMem
+{
+public:
+    VMem();
+    ~VMem();
+    virtual void* Malloc(size_t size);
+    virtual void* Realloc(void* pMem, size_t size);
+    virtual void Free(void* pMem);
+    virtual void GetLock(void);
+    virtual void FreeLock(void);
+    virtual int IsLocked(void);
+    virtual long Release(void);
+    virtual long AddRef(void);
+
+    inline BOOL CreateOk(void)
+    {
+	return m_hHeap != NULL;
+    };
+
+    void ReInit(void);
+
+protected:
+    void Init(void);
+    int Getmem(size_t size);
+    int HeapAdd(void* ptr, size_t size);
+    void* Expand(void* block, size_t size);
+    void WalkHeap(void);
+
+    HANDLE		m_hHeap;		    // memory heap for this script
+    char		m_FreeDummy[minAllocSize];  // dummy free block
+    PBLOCK		m_pFreeList;		    // pointer to first block on free list
+    PBLOCK		m_pRover;		    // roving pointer into the free list
+    HeapRec		m_heaps[maxHeaps];	    // list of all non-contiguous heap areas 
+    int			m_nHeaps;		    // no. of heaps in m_heaps 
+    long		m_lAllocSize;		    // current alloc size
+    long		m_lRefCount;		    // number of current users
+    CRITICAL_SECTION	m_cs;			    // access lock
+};
+
+// #define _DEBUG_MEM
+#ifdef _DEBUG_MEM
+#define ASSERT(f) if(!(f)) DebugBreak();
+
+inline void MEMODS(char *str)
+{
+    OutputDebugString(str);
+    OutputDebugString("\n");
+}
+
+inline void MEMODSlx(char *str, long x)
+{
+    char szBuffer[512];	
+    sprintf(szBuffer, "%s %lx\n", str, x);
+    OutputDebugString(szBuffer);
+}
+
+#define WALKHEAP() WalkHeap()
+#define WALKHEAPTRACE() m_pRover = NULL; WalkHeap()
+
+#else
+
+#define ASSERT(f)
+#define MEMODS(x)
+#define MEMODSlx(x, y)
+#define WALKHEAP()
+#define WALKHEAPTRACE()
+
+#endif
+
+
+VMem::VMem()
+{
+    m_lRefCount = 1;
+    BOOL bRet = (NULL != (m_hHeap = HeapCreate(HEAP_NO_SERIALIZE,
+				lAllocStart,	/* initial size of heap */
+				0)));		/* no upper limit on size of heap */
+    ASSERT(bRet);
+
+    InitializeCriticalSection(&m_cs);
+
+    Init();
+}
+
+VMem::~VMem(void)
+{
+    ASSERT(HeapValidate(m_hHeap, HEAP_NO_SERIALIZE, NULL));
+    WALKHEAPTRACE();
+    DeleteCriticalSection(&m_cs);
+    BOOL bRet = HeapDestroy(m_hHeap);
+    ASSERT(bRet);
+}
+
+void VMem::ReInit(void)
+{
+    for(int index = 0; index < m_nHeaps; ++index)
+	HeapFree(m_hHeap, HEAP_NO_SERIALIZE, m_heaps[index].base);
+
+    Init();
+}
+
+void VMem::Init(void)
+{   /*
+     * Initialize the free list by placing a dummy zero-length block on it.
+     * Set the number of non-contiguous heaps to zero.
+     */
+    m_pFreeList = m_pRover = (PBLOCK)(&m_FreeDummy[minBlockSize]);
+    PSIZE(m_pFreeList) = SIZE(m_pFreeList) = 0;
+    PREV(m_pFreeList) = NEXT(m_pFreeList) = m_pFreeList;
+
+    m_nHeaps = 0;
+    m_lAllocSize = lAllocStart;
+}
+
+void* VMem::Malloc(size_t size)
+{
+    WALKHEAP();
+
+    /*
+     * Adjust the real size of the block to be a multiple of sizeof(long), and add
+     * the overhead for the boundary tags.  Disallow negative or zero sizes.
+     */
+    size_t realsize = (size < blockOverhead) ? minAllocSize : (size_t)ROUND_UP(size) + minBlockSize;
+    if((int)realsize < minAllocSize || size == 0)
+	return NULL;
+
+    /*
+     * Start searching the free list at the rover.  If we arrive back at rover without
+     * finding anything, allocate some memory from the heap and try again.
+     */
+    PBLOCK ptr = m_pRover;	/* start searching at rover */
+    int loops = 2;		/* allow two times through the loop  */
+    for(;;) {
+	size_t lsize = SIZE(ptr);
+	ASSERT((lsize&1)==0);
+	/* is block big enough? */
+	if(lsize >= realsize) {	
+	    /* if the remainder is too small, don't bother splitting the block. */
+	    size_t rem = lsize - realsize;
+	    if(rem < minAllocSize) {
+		if(m_pRover == ptr)
+		    m_pRover = NEXT(ptr);
+
+		/* Unlink the block from the free list. */
+		Unlink(ptr);
+	    }
+	    else {
+		/*
+		 * split the block
+		 * The remainder is big enough to split off into a new block.
+		 * Use the end of the block, resize the beginning of the block
+		 * no need to change the free list.
+		 */
+		SetTags(ptr, rem);
+		ptr += SIZE(ptr);
+		lsize = realsize;
+	    }
+	    /* Set the boundary tags to mark it as allocated. */
+	    SetTags(ptr, lsize | 1);
+	    return ((void *)ptr);
+	}
+
+	/*
+	 * This block was unsuitable.  If we've gone through this list once already without
+	 * finding anything, allocate some new memory from the heap and try again.
+	 */
+	ptr = NEXT(ptr);
+	if(ptr == m_pRover) {
+	    if(!(loops-- && Getmem(realsize))) {
+		return NULL;
+	    }
+	    ptr = m_pRover;
+	}
+    }
+}
+
+void* VMem::Realloc(void* block, size_t size)
+{
+    WALKHEAP();
+
+    /* if size is zero, free the block. */
+    if(size == 0) {
+	Free(block);
+	return (NULL);
+    }
+
+    /* if block pointer is NULL, do a Malloc(). */
+    if(block == NULL)
+	return Malloc(size);
+
+    /*
+     * Grow or shrink the block in place.
+     * if the block grows then the next block will be used if free
+     */
+    if(Expand(block, size) != NULL)
+	return block;
+
+    /*
+     * adjust the real size of the block to be a multiple of sizeof(long), and add the
+     * overhead for the boundary tags.  Disallow negative or zero sizes.
+     */
+    size_t realsize = (size < blockOverhead) ? minAllocSize : (size_t)ROUND_UP(size) + minBlockSize;
+    if((int)realsize < minAllocSize)
+	return NULL;
+
+    /*
+     * see if the previous block is free, and is it big enough to cover the new size
+     * if merged with the current block.
+     */
+    PBLOCK ptr = (PBLOCK)block;
+    size_t cursize = SIZE(ptr) & ~1;
+    size_t psize = PSIZE(ptr);
+    if((psize&1) == 0 && (psize + cursize) >= realsize) {
+	PBLOCK prev = ptr - psize;
+	if(m_pRover == prev)
+	    m_pRover = NEXT(prev);
+
+	/* Unlink the next block from the free list. */
+	Unlink(prev);
+
+	/* Copy contents of old block to new location, make it the current block. */
+	memmove(prev, ptr, cursize);
+	cursize += psize;	/* combine sizes */
+	ptr = prev;
+
+	size_t rem = cursize - realsize;
+	if(rem >= minAllocSize) {
+	    /*
+	     * The remainder is big enough to be a new block.  Set boundary
+	     * tags for the resized block and the new block.
+	     */
+	    prev = ptr + realsize;
+	    /*
+	     * add the new block to the free list.
+	     * next block cannot be free
+	     */
+	    SetTags(prev, rem);
+	    AddToFreeList(prev, m_pFreeList);
+	    cursize = realsize;
+        }
+	/* Set the boundary tags to mark it as allocated. */
+	SetTags(ptr, cursize | 1);
+        return ((void *)ptr);
+    }
+
+    /* Allocate a new block, copy the old to the new, and free the old. */
+    if((ptr = (PBLOCK)Malloc(size)) != NULL) {
+	memmove(ptr, block, cursize-minBlockSize);
+	Free(block);
+    }
+    return ((void *)ptr);
+}
+
+void VMem::Free(void* p)
+{
+    WALKHEAP();
+
+    /* Ignore null pointer. */
+    if(p == NULL)
+	return;
+
+    PBLOCK ptr = (PBLOCK)p;
+
+    /* Check for attempt to free a block that's already free. */
+    size_t size = SIZE(ptr);
+    if((size&1) == 0) {
+	MEMODSlx("Attempt to free previously freed block", (long)p);
+	return;
+    }
+    size &= ~1;	/* remove allocated tag */
+
+    /* if previous block is free, add this block to it. */
+    int linked = FALSE;
+    size_t psize = PSIZE(ptr);
+    if((psize&1) == 0) {
+	ptr -= psize;	/* point to previous block */
+	size += psize;	/* merge the sizes of the two blocks */
+	linked = TRUE;	/* it's already on the free list */
+    }
+
+    /* if the next physical block is free, merge it with this block. */
+    PBLOCK next = ptr + size;	/* point to next physical block */
+    size_t nsize = SIZE(next);
+    if((nsize&1) == 0) {
+	/* block is free move rover if needed */
+	if(m_pRover == next)
+	    m_pRover = NEXT(next);
+
+	/* unlink the next block from the free list. */
+	Unlink(next);
+
+	/* merge the sizes of this block and the next block. */
+	size += nsize;
+    }
+
+    /* Set the boundary tags for the block; */
+    SetTags(ptr, size);
+
+    /* Link the block to the head of the free list. */
+    if(!linked) {
+	AddToFreeList(ptr, m_pFreeList);
+    }
+}
+
+void VMem::GetLock(void)
+{
+    EnterCriticalSection(&m_cs);
+}
+
+void VMem::FreeLock(void)
+{
+    LeaveCriticalSection(&m_cs);
+}
+
+int VMem::IsLocked(void)
+{
+    BOOL bAccessed = TryEnterCriticalSection(&m_cs);
+    if(bAccessed) {
+	LeaveCriticalSection(&m_cs);
+    }
+    return !bAccessed;
+}
+
+
+long VMem::Release(void)
+{
+    long lCount = InterlockedDecrement(&m_lRefCount);
+    if(!lCount)
+	delete this;
+    return lCount;
+}
+
+long VMem::AddRef(void)
+{
+    long lCount = InterlockedIncrement(&m_lRefCount);
+    return lCount;
+}
+
+
+int VMem::Getmem(size_t requestSize)
+{   /* returns -1 is successful 0 if not */
+    void *ptr;
+
+    /* Round up size to next multiple of 64K. */
+    size_t size = (size_t)ROUND_UP64K(requestSize);
+    
+    /*
+     * if the size requested is smaller than our current allocation size
+     * adjust up
+     */
+    if(size < (unsigned long)m_lAllocSize)
+	size = m_lAllocSize;
+
+    /* Update the size to allocate on the next request */
+    if(m_lAllocSize != lAllocMax)
+	m_lAllocSize <<= 1;
+
+    if(m_nHeaps != 0) {
+	/* Expand the last allocated heap */
+	ptr = HeapReAlloc(m_hHeap, HEAP_REALLOC_IN_PLACE_ONLY|HEAP_ZERO_MEMORY|HEAP_NO_SERIALIZE,
+		m_heaps[m_nHeaps-1].base,
+		m_heaps[m_nHeaps-1].len + size);
+	if(ptr != 0) {
+	    HeapAdd(((char*)ptr) + m_heaps[m_nHeaps-1].len, size);
+	    return -1;
+	}
+    }
+
+    /*
+     * if we didn't expand a block to cover the requested size
+     * allocate a new Heap
+     * the size of this block must include the additional dummy tags at either end
+     * the above ROUND_UP64K may not have added any memory to include this.
+     */
+    if(size == requestSize)
+	size = (size_t)ROUND_UP64K(requestSize+(sizeofTag*2));
+
+    ptr = HeapAlloc(m_hHeap, HEAP_ZERO_MEMORY|HEAP_NO_SERIALIZE, size);
+    if(ptr == 0) {
+	MEMODSlx("HeapAlloc failed on size!!!", size);
+	return 0;
+    }
+
+    HeapAdd(ptr, size);
+    return -1;
+}
+
+int VMem::HeapAdd(void *p, size_t size)
+{   /* if the block can be succesfully added to the heap, returns 0; otherwise -1. */
+    int index;
+
+    /* Check size, then round size down to next long word boundary. */
+    if(size < minAllocSize)
+	return -1;
+
+    size = (size_t)ROUND_DOWN(size);
+    PBLOCK ptr = (PBLOCK)p;
+
+    /*
+     * Search for another heap area that's contiguous with the bottom of this new area.
+     * (It should be extremely unusual to find one that's contiguous with the top).
+     */
+    for(index = 0; index < m_nHeaps; ++index) {
+	if(ptr == m_heaps[index].base + (int)m_heaps[index].len) {
+	    /*
+	     * The new block is contiguous with a previously allocated heap area.  Add its
+	     * length to that of the previous heap.  Merge it with the the dummy end-of-heap
+	     * area marker of the previous heap.
+	     */
+	    m_heaps[index].len += size;
+	    break;
+	}
+    }
+
+    if(index == m_nHeaps) {
+	/* The new block is not contiguous.  Add it to the heap list. */
+	if(m_nHeaps == maxHeaps) {
+	    return -1;	/* too many non-contiguous heaps */
+	}
+	m_heaps[m_nHeaps].base = ptr;
+	m_heaps[m_nHeaps].len = size;
+	m_nHeaps++;
+
+	/*
+	 * Reserve the first LONG in the block for the ending boundary tag of a dummy
+	 * block at the start of the heap area.
+	 */
+	size -= minBlockSize;
+	ptr += minBlockSize;
+	PSIZE(ptr) = 1;	/* mark the dummy previous block as allocated */
+    }
+
+    /*
+     * Convert the heap to one large block.  Set up its boundary tags, and those of
+     * marker block after it.  The marker block before the heap will already have
+     * been set up if this heap is not contiguous with the end of another heap.
+     */
+    SetTags(ptr, size | 1);
+    PBLOCK next = ptr + size;	/* point to dummy end block */
+    SIZE(next) = 1;	/* mark the dummy end block as allocated */
+
+    /*
+     * Link the block to the start of the free list by calling free().
+     * This will merge the block with any adjacent free blocks.
+     */
+    Free(ptr);
+    return 0;
+}
+
+
+void* VMem::Expand(void* block, size_t size)
+{
+    /*
+     * Adjust the size of the block to be a multiple of sizeof(long), and add the
+     * overhead for the boundary tags.  Disallow negative or zero sizes.
+     */
+    size_t realsize = (size < blockOverhead) ? minAllocSize : (size_t)ROUND_UP(size) + minBlockSize;
+    if((int)realsize < minAllocSize || size == 0)
+	return NULL;
+
+    PBLOCK ptr = (PBLOCK)block; 
+
+    /* if the current size is the same as requested, do nothing. */
+    size_t cursize = SIZE(ptr) & ~1;
+    if(cursize == realsize) {
+	return block;
+    }
+
+    /* if the block is being shrunk, convert the remainder of the block into a new free block. */
+    if(realsize <= cursize) {
+	size_t nextsize = cursize - realsize;	/* size of new remainder block */
+	if(nextsize >= minAllocSize) {
+	    /*
+	     * Split the block
+	     * Set boundary tags for the resized block and the new block.
+	     */
+	    SetTags(ptr, realsize | 1);
+	    ptr += realsize;
+
+	    /*
+	     * add the new block to the free list.
+	     * call Free to merge this block with next block if free
+	     */
+	    SetTags(ptr, nextsize | 1);
+	    Free(ptr);
+	}
+
+	return block;
+    }
+
+    PBLOCK next = ptr + cursize;
+    size_t nextsize = SIZE(next);
+
+    /* Check the next block for consistency.*/
+    if((nextsize&1) == 0 && (nextsize + cursize) >= realsize) {
+	/*
+	 * The next block is free and big enough.  Add the part that's needed
+	 * to our block, and split the remainder off into a new block.
+	 */
+	if(m_pRover == next)
+	    m_pRover = NEXT(next);
+
+	/* Unlink the next block from the free list. */
+	Unlink(next);
+	cursize += nextsize;	/* combine sizes */
+
+	size_t rem = cursize - realsize;	/* size of remainder */
+	if(rem >= minAllocSize) {
+	    /*
+	     * The remainder is big enough to be a new block.
+	     * Set boundary tags for the resized block and the new block.
+	     */
+	    next = ptr + realsize;
+	    /*
+	     * add the new block to the free list.
+	     * next block cannot be free
+	     */
+	    SetTags(next, rem);
+	    AddToFreeList(next, m_pFreeList);
+	    cursize = realsize;
+        }
+	/* Set the boundary tags to mark it as allocated. */
+	SetTags(ptr, cursize | 1);
+	return ((void *)ptr);
+    }
+    return NULL;
+}
+
+#ifdef _DEBUG_MEM
+#define LOG_FILENAME "P:\\Apps\\Perl\\Result.txt"
+
+void MemoryUsageMessage(char *str, long x, long y, int c)
+{
+    static FILE* fp = NULL;
+    char szBuffer[512];
+    if(str) {
+	if(!fp)
+	    fp = fopen(LOG_FILENAME, "w");
+	sprintf(szBuffer, str, x, y, c);
+	fputs(szBuffer, fp);
+    }
+    else {
+	fflush(fp);
+	fclose(fp);
+    }
+}
+
+void VMem::WalkHeap(void)
+{
+    if(!m_pRover) {
+	MemoryUsageMessage("VMem heaps used %d\n", m_nHeaps, 0, 0);
+    }
+
+    /* Walk all the heaps - verify structures */
+    for(int index = 0; index < m_nHeaps; ++index) {
+	PBLOCK ptr = m_heaps[index].base;
+	size_t size = m_heaps[index].len;
+	ASSERT(HeapValidate(m_hHeap, HEAP_NO_SERIALIZE, p));
+
+	/* set over reserved header block */
+	size -= minBlockSize;
+	ptr += minBlockSize;
+	PBLOCK pLast = ptr + size;
+	ASSERT(PSIZE(ptr) == 1); /* dummy previous block is allocated */
+	ASSERT(SIZE(pLast) == 1); /* dummy next block is allocated */
+	while(ptr < pLast) {
+	    ASSERT(ptr > m_heaps[index].base);
+	    size_t cursize = SIZE(ptr) & ~1;
+	    ASSERT((PSIZE(ptr+cursize) & ~1) == cursize);
+	    if(!m_pRover) {
+		MemoryUsageMessage("Memory Block %08x: Size %08x %c\n", (long)ptr, cursize, (SIZE(p)&1) ? 'x' : ' ');
+	    }
+	    if(!(SIZE(ptr)&1)) {
+		/* this block is on the free list */
+		PBLOCK tmp = NEXT(ptr);
+		while(tmp != ptr) {
+		    ASSERT((SIZE(tmp)&1)==0);
+		    if(tmp == m_pFreeList)
+			break;
+		    ASSERT(NEXT(tmp));
+		    tmp = NEXT(tmp);
+		}
+		if(tmp == ptr) {
+		    MemoryUsageMessage("Memory Block %08x: Size %08x free but not in free list\n", (long)ptr, cursize, 0);
+		}
+	    }
+	    ptr += cursize;
+	}
+    }
+    if(!m_pRover) {
+	MemoryUsageMessage(NULL, 0, 0, 0);
+    }
+}
+#endif
+
+#endif	/* ___VMEM_H_INC___ */