1 files changed, 23 insertions, 25 deletions

diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index 1389382..df0618c 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -35,14 +35,14 @@
 #endif
 
 /*
- * A mask (should be 2**n-1) that is used to work out when the bytecode engine
- * should call Tcl_AsyncReady() to see whether there is a signal that needs
- * handling.
+ * A counter that is used to work out when the bytecode engine should call
+ * Tcl_AsyncReady() to see whether there is a signal that needs handling, and
+ * other expensive periodic operations.
  */
 
-#ifndef ASYNC_CHECK_COUNT_MASK
-#   define ASYNC_CHECK_COUNT_MASK	63
-#endif /* !ASYNC_CHECK_COUNT_MASK */
+#ifndef ASYNC_CHECK_COUNT
+#   define ASYNC_CHECK_COUNT	64
+#endif /* !ASYNC_CHECK_COUNT */
 
 /*
  * Boolean flag indicating whether the Tcl bytecode interpreter has been
@@ -1499,11 +1499,9 @@ ExprObjCallback(
  *
  * Results:
  *	A (ByteCode *) is returned pointing to the resulting ByteCode.
- *	The caller must manage its refCount and arrange for a call to
- *	TclCleanupByteCode() when the last reference disappears.
  *
  * Side effects:
- *	The Tcl_ObjType of objPtr is changed to the "bytecode" type,
+ *	The Tcl_ObjType of objPtr is changed to the "exprcode" type,
  *	and the ByteCode is kept in the internal rep (along with context
  *	data for checking validity) for faster operations the next time
  *	CompileExprObj is called on the same value.
@@ -1536,7 +1534,7 @@ CompileExprObj(
 		|| (codePtr->nsPtr != namespacePtr)
 		|| (codePtr->nsEpoch != namespacePtr->resolverEpoch)
 		|| (codePtr->localCachePtr != iPtr->varFramePtr->localCachePtr)) {
-	    FreeExprCodeInternalRep(objPtr);
+	    TclFreeIntRep(objPtr);
 	}
     }
     if (objPtr->typePtr != &exprCodeType) {
@@ -1567,10 +1565,8 @@ CompileExprObj(
 	 */
 
 	TclEmitOpcode(INST_DONE, &compEnv);
-	TclInitByteCodeObj(objPtr, &compEnv);
-	objPtr->typePtr = &exprCodeType;
+	codePtr = TclInitByteCodeObj(objPtr, &exprCodeType, &compEnv);
 	TclFreeCompileEnv(&compEnv);
-	codePtr = objPtr->internalRep.twoPtrValue.ptr1;
 	if (iPtr->varFramePtr->localCachePtr) {
 	    codePtr->localCachePtr = iPtr->varFramePtr->localCachePtr;
 	    codePtr->localCachePtr->refCount++;
@@ -1644,10 +1640,7 @@ FreeExprCodeInternalRep(
 {
     ByteCode *codePtr = objPtr->internalRep.twoPtrValue.ptr1;
 
-    objPtr->typePtr = NULL;
-    if (codePtr->refCount-- <= 1) {
-	TclCleanupByteCode(codePtr);
-    }
+    TclReleaseByteCode(codePtr);
 }
 
 /*
@@ -2033,7 +2026,7 @@ TclNRExecuteByteCode(
 		* sizeof(void *);
     int numWords = (size + sizeof(Tcl_Obj *) - 1) / sizeof(Tcl_Obj *);
 
-    codePtr->refCount++;
+    TclPreserveByteCode(codePtr);
 
     /*
      * Reserve the stack, setup the TEBCdataPtr (TD) and CallFrame
@@ -2115,8 +2108,14 @@ TEBCresume(
      * sporadically: no special need for speed.
      */
 
-    int instructionCount = 0;	/* Counter that is used to work out when to
-				 * call Tcl_AsyncReady() */
+    unsigned interruptCounter = 1;
+				/* Counter that is used to work out when to
+				 * call Tcl_AsyncReady(). This must be 1
+				 * initially so that we call the async-check
+				 * stanza early, otherwise there are command
+				 * sequences that can make the interpreter
+				 * busy-loop without an opportunity to
+				 * recognise an interrupt. */
     const char *curInstName;
 #ifdef TCL_COMPILE_DEBUG
     int traceInstructions;	/* Whether we are doing instruction-level
@@ -2314,10 +2313,11 @@ TEBCresume(
 
     /*
      * Check for asynchronous handlers [Bug 746722]; we do the check every
-     * ASYNC_CHECK_COUNT_MASK instruction, of the form (2**n-1).
+     * ASYNC_CHECK_COUNT instructions.
      */
 
-    if ((instructionCount++ & ASYNC_CHECK_COUNT_MASK) == 0) {
+    if ((--interruptCounter) == 0) {
+	interruptCounter = ASYNC_CHECK_COUNT;
 	DECACHE_STACK_INFO();
 	if (TclAsyncReady(iPtr)) {
 	    result = Tcl_AsyncInvoke(interp, result);
@@ -8185,9 +8185,7 @@ TEBCresume(
     }
 
     iPtr->cmdFramePtr = bcFramePtr->nextPtr;
-    if (codePtr->refCount-- <= 1) {
-	TclCleanupByteCode(codePtr);
-    }
+    TclReleaseByteCode(codePtr);
     TclStackFree(interp, TD);	/* free my stack */
 
     return result;