Attachment "alloc3.patch" to
ticket [1851832fff]
added by
msofer
2007-12-17 20:44:57.
Index: generic/tclAlloc.c
===================================================================
RCS file: /cvsroot/tcl/tcl/generic/tclAlloc.c,v
retrieving revision 1.26
diff -u -r1.26 tclAlloc.c
--- generic/tclAlloc.c 13 Dec 2007 15:23:14 -0000 1.26
+++ generic/tclAlloc.c 17 Dec 2007 13:43:11 -0000
@@ -44,16 +44,6 @@
#endif
/*
- * Alignment for allocated memory.
- */
-
-#if defined(__APPLE__)
-#define ALLOCALIGN 16
-#else
-#define ALLOCALIGN 8
-#endif
-
-/*
* The overhead on a block is at least 8 bytes. When free, this space contains
* a pointer to the next free block, and the bottom two bits must be zero.
* When in use, the first byte is set to MAGIC, and the second byte is the
@@ -66,7 +56,7 @@
union overhead {
union overhead *next; /* when free */
- unsigned char padding[ALLOCALIGN]; /* align struct to ALLOCALIGN bytes */
+ unsigned char padding[TCL_ALLOCALIGN]; /* align struct to TCL_ALLOCALIGN bytes */
struct {
unsigned char magic0; /* magic number */
unsigned char index; /* bucket # */
@@ -110,7 +100,7 @@
* precedes the data area returned to the user.
*/
-#define MINBLOCK ((sizeof(union overhead) + (ALLOCALIGN-1)) & ~(ALLOCALIGN-1))
+#define MINBLOCK ((sizeof(union overhead) + (TCL_ALLOCALIGN-1)) & ~(TCL_ALLOCALIGN-1))
#define NBUCKETS (13 - (MINBLOCK >> 4))
#define MAXMALLOC (1<<(NBUCKETS+2))
static union overhead *nextf[NBUCKETS];
Index: generic/tclExecute.c
===================================================================
RCS file: /cvsroot/tcl/tcl/generic/tclExecute.c,v
retrieving revision 1.357
diff -u -r1.357 tclExecute.c
--- generic/tclExecute.c 13 Dec 2007 15:23:16 -0000 1.357
+++ generic/tclExecute.c 17 Dec 2007 13:43:12 -0000
@@ -836,6 +836,36 @@
}
/*
+ * Auxiliary code to insure that GrowEvaluationStack always returns correctly
+ * aligned memory. This assumes that TCL_ALLOCALIGN is a multiple of the
+ * wordsize 'sizeof(Tcl_Obj *)'.
+ */
+
+#define WALLOCALIGN \
+ (TCL_ALLOCALIGN/sizeof(Tcl_Obj *))
+
+static inline int
+OFFSET(
+ Tcl_Obj **markerPtr)
+{
+ /*
+ * Note that we are only interested in the low bits of the address, so
+ * that the fact that PTR2INT may lose the high bits is irrelevant.
+ */
+
+ int mask, base, new;
+
+ mask = WALLOCALIGN-1;
+ base = (PTR2INT(markerPtr) & mask);
+ new = (base + 1 + mask) & ~mask;
+ return (new - base);
+}
+
+#define MEMSTART(markerPtr) \
+ ((markerPtr) + OFFSET(markerPtr))
+
+
+/*
*----------------------------------------------------------------------
*
* GrowEvaluationStack --
@@ -865,36 +895,44 @@
ExecStack *esPtr = eePtr->execStackPtr, *oldPtr = NULL;
int newBytes, newElems, currElems;
int needed = growth - (esPtr->endPtr - esPtr->tosPtr);
- Tcl_Obj **markerPtr = esPtr->markerPtr;
+ Tcl_Obj **markerPtr = esPtr->markerPtr, **memStart;
if (move) {
if (!markerPtr) {
Tcl_Panic("STACK: Reallocating with no previous alloc");
}
if (needed <= 0) {
- return markerPtr + 1;
+ return MEMSTART(markerPtr);
}
- } else if (needed < 0) {
- /*
- * Put a marker pointing to the previous marker in this stack, and
- * store it in esPtr as the current marker. Return a pointer to one
- * word past the marker.
- */
+ } else {
+ Tcl_Obj **tmpMarkerPtr = esPtr->tosPtr + 1;
+ int offset = OFFSET(tmpMarkerPtr);
- esPtr->markerPtr = ++esPtr->tosPtr;
- *esPtr->markerPtr = (Tcl_Obj *) markerPtr;
- return esPtr->markerPtr + 1;
+ if (needed + offset < 0) {
+ /*
+ * Put a marker pointing to the previous marker in this stack, and
+ * store it in esPtr as the current marker. Return a pointer to
+ * the start of aligned memory.
+ */
+
+ esPtr->markerPtr = tmpMarkerPtr;
+ memStart = tmpMarkerPtr + offset;
+ esPtr->tosPtr = memStart - 1;
+ *esPtr->markerPtr = (Tcl_Obj *) markerPtr;
+ return memStart;
+ }
}
/*
* Reset move to hold the number of words to be moved to new stack (if
- * any) and growth to hold the complete stack requirements.
+ * any) and growth to hold the complete stack requirements: add the marker
+ * and maximal possible offset.
*/
if (move) {
- move = esPtr->tosPtr - markerPtr;
+ move = esPtr->tosPtr - MEMSTART(markerPtr) + 1;
}
- needed = growth + move + 1; /* Add the marker. */
+ needed = growth + move + WALLOCALIGN - 1;
/*
* Check if there is enough room in the next stack (if there is one, it
@@ -949,10 +987,12 @@
*/
esPtr->stackWords[0] = NULL;
- esPtr->markerPtr = esPtr->tosPtr = &esPtr->stackWords[0];
-
+ esPtr->markerPtr = &esPtr->stackWords[0];
+ memStart = MEMSTART(esPtr->markerPtr);
+ esPtr->tosPtr = memStart - 1;
+
if (move) {
- memcpy(&esPtr->stackWords[1], (markerPtr+1), move*sizeof(Tcl_Obj *));
+ memcpy(memStart, MEMSTART(markerPtr), move*sizeof(Tcl_Obj *));
esPtr->tosPtr += move;
oldPtr->markerPtr = (Tcl_Obj **) *markerPtr;
oldPtr->tosPtr = markerPtr-1;
@@ -966,7 +1006,7 @@
DeleteExecStack(oldPtr);
}
- return &esPtr->stackWords[1];
+ return memStart;
}
/*
@@ -1043,7 +1083,7 @@
esPtr = eePtr->execStackPtr;
markerPtr = esPtr->markerPtr;
- if ((markerPtr+1) != (Tcl_Obj **)freePtr) {
+ if (MEMSTART(markerPtr) != (Tcl_Obj **)freePtr) {
Tcl_Panic("TclStackFree: incorrect freePtr. Call out of sequence?");
}
@@ -1104,7 +1144,7 @@
esPtr = eePtr->execStackPtr;
markerPtr = esPtr->markerPtr;
- if ((markerPtr+1) != (Tcl_Obj **)ptr) {
+ if (MEMSTART(markerPtr) != (Tcl_Obj **)ptr) {
Tcl_Panic("TclStackRealloc: incorrect ptr. Call out of sequence?");
}
Index: generic/tclInt.h
===================================================================
RCS file: /cvsroot/tcl/tcl/generic/tclInt.h,v
retrieving revision 1.358
diff -u -r1.358 tclInt.h
--- generic/tclInt.h 13 Dec 2007 15:23:18 -0000 1.358
+++ generic/tclInt.h 17 Dec 2007 13:43:13 -0000
@@ -2034,6 +2034,17 @@
#define UCHAR(c) ((unsigned char) (c))
/*
+ * This macro is used to properly align the memory allocated by Tcl, giving
+ * the same alignment as the native malloc
+ */
+
+#if defined(__APPLE__)
+#define TCL_ALLOCALIGN 16
+#else
+#define TCL_ALLOCALIGN (2*sizeof(void *))
+#endif
+
+/*
* This macro is used to determine the offset needed to safely allocate any
* data structure in memory. Given a starting offset or size, it "rounds up"
* or "aligns" the offset to the next 8-byte boundary so that any data
Index: generic/tclThreadAlloc.c
===================================================================
RCS file: /cvsroot/tcl/tcl/generic/tclThreadAlloc.c,v
retrieving revision 1.24
diff -u -r1.24 tclThreadAlloc.c
--- generic/tclThreadAlloc.c 13 Dec 2007 15:23:20 -0000 1.24
+++ generic/tclThreadAlloc.c 17 Dec 2007 13:43:14 -0000
@@ -40,16 +40,6 @@
#define NOBJHIGH 1200
/*
- * Alignment for allocated memory.
- */
-
-#if defined(__APPLE__)
-#define ALLOCALIGN 16
-#else
-#define ALLOCALIGN 8
-#endif
-
-/*
* The following union stores accounting information for each block including
* two small magic numbers and a bucket number when in use or a next pointer
* when free. The original requested size (not including the Block overhead)
@@ -69,7 +59,7 @@
} u;
size_t reqSize; /* Requested allocation size. */
} b;
- unsigned char padding[ALLOCALIGN];
+ unsigned char padding[TCL_ALLOCALIGN];
} Block;
#define nextBlock b.u.next
#define sourceBucket b.u.s.bucket
@@ -83,7 +73,7 @@
* of buckets in the bucket cache.
*/
-#define MINALLOC ((sizeof(Block) + 8 + (ALLOCALIGN-1)) & ~(ALLOCALIGN-1))
+#define MINALLOC ((sizeof(Block) + 8 + (TCL_ALLOCALIGN-1)) & ~(TCL_ALLOCALIGN-1))
#define NBUCKETS (11 - (MINALLOC >> 5))
#define MAXALLOC (MINALLOC << (NBUCKETS - 1))
