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-rw-r--r--generic/tclExecute.c92
1 files changed, 73 insertions, 19 deletions
diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index a1ba0cb..24613aa 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -11,7 +11,7 @@
* See the file "license.terms" for information on usage and redistribution
* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
- * RCS: @(#) $Id: tclExecute.c,v 1.86 2002/07/31 09:57:34 dkf Exp $
+ * RCS: @(#) $Id: tclExecute.c,v 1.87 2002/08/01 20:02:11 msofer Exp $
*/
#include "tclInt.h"
@@ -513,11 +513,22 @@ TclCreateExecEnv(interp)
* environment is being created. */
{
ExecEnv *eePtr = (ExecEnv *) ckalloc(sizeof(ExecEnv));
+ Tcl_Obj **stackPtr;
+
+ stackPtr = (Tcl_Obj **)
+ ckalloc((size_t) (TCL_STACK_INITIAL_SIZE * sizeof(Tcl_Obj *)));
+
+ /*
+ * Use the bottom pointer to keep a reference count; the
+ * execution environment holds a reference.
+ */
+
+ stackPtr++;
+ eePtr->stackPtr = stackPtr;
+ stackPtr[-1] = (Tcl_Obj *) ((char *) 1);
- eePtr->stackPtr = (Tcl_Obj **)
- ckalloc((unsigned) (TCL_STACK_INITIAL_SIZE * sizeof(Tcl_Obj *)));
eePtr->stackTop = -1;
- eePtr->stackEnd = (TCL_STACK_INITIAL_SIZE - 1);
+ eePtr->stackEnd = (TCL_STACK_INITIAL_SIZE - 2);
eePtr->errorInfo = Tcl_NewStringObj("::errorInfo", -1);
Tcl_IncrRefCount(eePtr->errorInfo);
@@ -558,7 +569,11 @@ void
TclDeleteExecEnv(eePtr)
ExecEnv *eePtr; /* Execution environment to free. */
{
- Tcl_EventuallyFree((ClientData)eePtr->stackPtr, TCL_DYNAMIC);
+ if (eePtr->stackPtr[-1] == (Tcl_Obj *) ((char *) 1)) {
+ ckfree((char *) (eePtr->stackPtr-1));
+ } else {
+ panic("ERROR: freeing an execEnv whose stack is still in use.\n");
+ }
TclDecrRefCount(eePtr->errorInfo);
TclDecrRefCount(eePtr->errorCode);
ckfree((char *) eePtr);
@@ -621,18 +636,44 @@ GrowEvaluationStack(eePtr)
int newElems = 2*currElems;
int currBytes = currElems * sizeof(Tcl_Obj *);
int newBytes = 2*currBytes;
- Tcl_Obj **newStackPtr = (Tcl_Obj **) ckalloc((unsigned) newBytes);
+ Tcl_Obj **newStackPtr;
+ Tcl_Obj **oldStackPtr = eePtr->stackPtr;
/*
- * Copy the existing stack items to the new stack space, free the old
- * storage if appropriate, and mark new space as malloc'ed.
+ * We keep the stack reference count as a (char *), as that
+ * works nicely as a portable pointer-sized counter.
+ */
+
+ char *refCount = (char *) oldStackPtr[-1];
+
+ /*
+ * Realloc the stack: copy existing stack items to the new stack
+ * space, free the old storage if appropriate.
*/
- memcpy((VOID *) newStackPtr, (VOID *) eePtr->stackPtr,
- (size_t) currBytes);
- Tcl_EventuallyFree((ClientData)eePtr->stackPtr, TCL_DYNAMIC);
+ newStackPtr = (Tcl_Obj **) ckrealloc((VOID *) (oldStackPtr-1),
+ (unsigned) newBytes);
+ newStackPtr++;
eePtr->stackPtr = newStackPtr;
- eePtr->stackEnd = (newElems - 1); /* i.e. index of last usable item */
+ eePtr->stackEnd = (newElems - 2); /* index of last usable item */
+
+ if (newStackPtr != oldStackPtr) {
+ /*
+ * The stack was moved; update the refCounts.
+ */
+
+ newStackPtr[-1] = (Tcl_Obj *) ((char *) 1);
+ if (refCount == (char *) 1) {
+ ckfree((VOID *) (oldStackPtr-1));
+ } else {
+ /*
+ * Remove the reference corresponding to the
+ * environment pointer.
+ */
+
+ oldStackPtr[-1] = (Tcl_Obj *) (refCount-1);
+ }
+ }
}
/*
@@ -1304,10 +1345,20 @@ TclExecuteByteCode(interp, codePtr)
{
int objc = opnd; /* The number of arguments. */
Tcl_Obj **objv; /* The array of argument objects. */
- Tcl_Obj **preservedStack;
- /* Reference to memory block containing
+
+ /*
+ * We keep the stack reference count as a (char *), as that
+ * works nicely as a portable pointer-sized counter.
+ */
+
+ char **preservedStackRefCountPtr;
+
+ /*
+ * Reference to memory block containing
* objv array (must be kept live throughout
- * trace and command invokations.) */
+ * trace and command invokations.)
+ */
+
objv = &(stackPtr[stackTop - (objc-1)]);
#ifdef TCL_COMPILE_DEBUG
@@ -1364,15 +1415,15 @@ TclExecuteByteCode(interp, codePtr)
/*
* A reference to part of the stack vector itself
- * escapes our control, so must use preserve/release
+ * escapes our control: increase its refCount
* to stop it from being deallocated by a recursive
* call to ourselves. The extra variable is needed
* because all others are liable to change due to the
* trace procedures.
*/
- Tcl_Preserve((ClientData)stackPtr);
- preservedStack = stackPtr;
+ preservedStackRefCountPtr = (char **) (stackPtr-1);
+ ++*preservedStackRefCountPtr;
/*
* Finally, let TclEvalObjvInternal handle the command.
@@ -1389,7 +1440,10 @@ TclExecuteByteCode(interp, codePtr)
* going to be used from now on.
*/
- Tcl_Release((ClientData) preservedStack);
+ --*preservedStackRefCountPtr;
+ if (*preservedStackRefCountPtr == (char *) 0) {
+ ckfree((VOID *) preservedStackRefCountPtr);
+ }
if (result == TCL_OK) {
/*