Merge back the improved [break] and [continue] compilation.

7 files changed, 532 insertions, 57 deletions

diff --git a/ChangeLog b/ChangeLog
index a98f995..30d0f0d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2013-06-03  Donal K. Fellows  <dkf@users.sf.net>
+
+	* generic/tclCompCmds.c (TclCompileBreakCmd, TclCompileContinueCmd):
+	Added code to allow [break] and [continue] to be issued as a jump (in
+	the most common cases) rather than using the more expensive exception
+	processing path in the bytecode engine. [Bug 3614226]: Partial fix for
+	the issues relating to cleaning up the stack when dealing with [break]
+	and [continue].
+
 2013-05-27 Harald Oehlmann  <oehhar@users.sf.net>
 
 	* library/msgcat/msgcat.tcl: [Bug 3036566]: Also get locale from
diff --git a/generic/tclAssembly.c b/generic/tclAssembly.c
index 0fe50b3a..d1af8c6 100644
--- a/generic/tclAssembly.c
+++ b/generic/tclAssembly.c
@@ -650,7 +650,7 @@ BBEmitOpcode(
     }
 
     TclEmitInt1(op, envPtr);
-    envPtr->atCmdStart = ((op) == INST_START_CMD);
+    TclUpdateAtCmdStart(op, envPtr);
     BBUpdateStackReqs(bbPtr, tblIdx, count);
 }
 
@@ -711,7 +711,7 @@ BBEmitInst1or4(
     } else {
 	TclEmitInt4(param, envPtr);
     }
-    envPtr->atCmdStart = ((op) == INST_START_CMD);
+    TclUpdateAtCmdStart(op, envPtr);
     BBUpdateStackReqs(bbPtr, tblIdx, count);
 }
 
diff --git a/generic/tclCompCmds.c b/generic/tclCompCmds.c
index 7046e54..3046841 100644
--- a/generic/tclCompCmds.c
+++ b/generic/tclCompCmds.c
@@ -480,23 +480,55 @@ TclCompileBreakCmd(
 				 * compiled. */
     CompileEnv *envPtr)		/* Holds resulting instructions. */
 {
+    ExceptionRange *rangePtr;
+    ExceptionAux *auxPtr;
+
     if (parsePtr->numWords != 1) {
 	return TCL_ERROR;
     }
 
     /*
+     * Find the innermost exception range that contains this command.
+     */
+
+    rangePtr = TclGetInnermostExceptionRange(envPtr, TCL_BREAK, &auxPtr);
+    if (rangePtr && rangePtr->type == LOOP_EXCEPTION_RANGE) {
+	int toPop = envPtr->currStackDepth - auxPtr->stackDepth;
+
+	/*
+	 * Pop off the extra stack frames.
+	 */
+
+	while (toPop > 0) {
+	    TclEmitOpcode(INST_POP, envPtr);
+	    TclAdjustStackDepth(1, envPtr);
+	    toPop--;
+	}
+
+	if (envPtr->expandCount == auxPtr->expandTarget) {
+	    /*
+	     * Found the target! Also, no built-up expansion stack. No need
+	     * for a nasty INST_BREAK here.
+	     */
+
+	    TclAddLoopBreakFixup(envPtr, auxPtr);
+	    goto done;
+	}
+    }
+
+    /*
      * Emit a break instruction.
      */
 
     TclEmitOpcode(INST_BREAK, envPtr);
-#ifdef TCL_COMPILE_DEBUG
+
+  done:
     /*
-     * Instructions that raise exceptions don't really have to follow
-     * the usual stack management rules.  But the checker wants them
-     * followed, so lie about stack usage to make it happy.
+     * Instructions that raise exceptions don't really have to follow the
+     * usual stack management rules, but the cleanup code does.
      */
+
     TclAdjustStackDepth(1, envPtr);
-#endif
     return TCL_OK;
 }
 
@@ -602,7 +634,7 @@ TclCompileCatchCmd(
      * uses.
      */
 
-    range = DeclareExceptionRange(envPtr, CATCH_EXCEPTION_RANGE);
+    range = TclCreateExceptRange(CATCH_EXCEPTION_RANGE, envPtr);
 
     /*
      * If the body is a simple word, compile a BEGIN_CATCH instruction,
@@ -790,6 +822,9 @@ TclCompileContinueCmd(
 				 * compiled. */
     CompileEnv *envPtr)		/* Holds resulting instructions. */
 {
+    ExceptionRange *rangePtr;
+    ExceptionAux *auxPtr;
+
     /*
      * There should be no argument after the "continue".
      */
@@ -799,11 +834,48 @@ TclCompileContinueCmd(
     }
 
     /*
+     * See if we can find a valid continueOffset (i.e., not -1) in the
+     * innermost containing exception range.
+     */
+
+    rangePtr = TclGetInnermostExceptionRange(envPtr, TCL_CONTINUE, &auxPtr);
+    if (rangePtr && rangePtr->type == LOOP_EXCEPTION_RANGE) {
+	int toPop = envPtr->currStackDepth - auxPtr->stackDepth;
+
+	/*
+	 * Pop off the extra stack frames.
+	 */
+
+	while (toPop > 0) {
+	    TclEmitOpcode(INST_POP, envPtr);
+	    TclAdjustStackDepth(1, envPtr);
+	    toPop--;
+	}
+
+	if (envPtr->expandCount == auxPtr->expandTarget) {
+	    /*
+	     * Found the target! Also, no built-up expansion stack. No need
+	     * for a nasty INST_CONTINUE here.
+	     */
+
+	    TclAddLoopContinueFixup(envPtr, auxPtr);
+	    goto done;
+	}
+    }
+
+    /*
      * Emit a continue instruction.
      */
 
     TclEmitOpcode(INST_CONTINUE, envPtr);
-    PushStringLiteral(envPtr, "");	/* Evil hack! */
+
+  done:
+    /*
+     * Instructions that raise exceptions don't really have to follow the
+     * usual stack management rules, but the cleanup code does.
+     */
+
+    TclAdjustStackDepth(1, envPtr);
     return TCL_OK;
 }
 
@@ -1256,7 +1328,7 @@ TclCompileDictMergeCmd(
      * For each of the remaining dictionaries...
      */
 
-    outLoop = DeclareExceptionRange(envPtr, CATCH_EXCEPTION_RANGE);
+    outLoop = TclCreateExceptRange(CATCH_EXCEPTION_RANGE, envPtr);
     TclEmitInstInt4(		INST_BEGIN_CATCH4, outLoop,	envPtr);
     ExceptionRangeStarts(envPtr, outLoop);
     for (i=2 ; i<parsePtr->numWords ; i++) {
@@ -1469,7 +1541,7 @@ CompileDictEachCmd(
      * started by Tcl_DictObjFirst above.
      */
 
-    catchRange = DeclareExceptionRange(envPtr, CATCH_EXCEPTION_RANGE);
+    catchRange = TclCreateExceptRange(CATCH_EXCEPTION_RANGE, envPtr);
     TclEmitInstInt4(	INST_BEGIN_CATCH4, catchRange,		envPtr);
     ExceptionRangeStarts(envPtr, catchRange);
 
@@ -1487,7 +1559,7 @@ CompileDictEachCmd(
      * Set up the loop exception targets.
      */
 
-    loopRange = DeclareExceptionRange(envPtr, LOOP_EXCEPTION_RANGE);
+    loopRange = TclCreateExceptRange(LOOP_EXCEPTION_RANGE, envPtr);
     ExceptionRangeStarts(envPtr, loopRange);
 
     /*
@@ -1535,6 +1607,7 @@ CompileDictEachCmd(
      */
 
     ExceptionRangeTarget(envPtr, loopRange, breakOffset);
+    TclFinalizeLoopExceptionRange(envPtr, loopRange);
     TclEmitInstInt1(	INST_UNSET_SCALAR, 0,			envPtr);
     TclEmitInt4(		infoIndex,			envPtr);
     TclEmitOpcode(	INST_END_CATCH,				envPtr);
@@ -1713,7 +1786,7 @@ TclCompileDictUpdateCmd(
     TclEmitInstInt4(	INST_DICT_UPDATE_START, dictIndex,	envPtr);
     TclEmitInt4(	infoIndex,				envPtr);
 
-    range = DeclareExceptionRange(envPtr, CATCH_EXCEPTION_RANGE);
+    range = TclCreateExceptRange(CATCH_EXCEPTION_RANGE, envPtr);
     TclEmitInstInt4(	INST_BEGIN_CATCH4, range,		envPtr);
 
     ExceptionRangeStarts(envPtr, range);
@@ -2070,7 +2143,7 @@ TclCompileDictWithCmd(
      * Now the body of the [dict with].
      */
 
-    range = DeclareExceptionRange(envPtr, CATCH_EXCEPTION_RANGE);
+    range = TclCreateExceptRange(CATCH_EXCEPTION_RANGE, envPtr);
     TclEmitInstInt4(		INST_BEGIN_CATCH4, range,	envPtr);
 
     ExceptionRangeStarts(envPtr, range);
@@ -2352,15 +2425,6 @@ TclCompileForCmd(
     }
 
     /*
-     * Create ExceptionRange records for the body and the "next" command. The
-     * "next" command's ExceptionRange supports break but not continue (and
-     * has a -1 continueOffset).
-     */
-
-    bodyRange = DeclareExceptionRange(envPtr, LOOP_EXCEPTION_RANGE);
-    nextRange = TclCreateExceptRange(LOOP_EXCEPTION_RANGE, envPtr);
-
-    /*
      * Inline compile the initial command.
      */
 
@@ -2386,6 +2450,7 @@ TclCompileForCmd(
      * Compile the loop body.
      */
 
+    bodyRange = TclCreateExceptRange(LOOP_EXCEPTION_RANGE, envPtr);
     bodyCodeOffset = ExceptionRangeStarts(envPtr, bodyRange);
     SetLineInformation(4);
     CompileBody(envPtr, bodyTokenPtr, interp);
@@ -2394,9 +2459,13 @@ TclCompileForCmd(
     TclEmitOpcode(INST_POP, envPtr);
 
     /*
-     * Compile the "next" subcommand.
+     * Compile the "next" subcommand. Note that this exception range will not
+     * have a continueOffset (other than -1) connected to it; it won't trap
+     * TCL_CONTINUE but rather just TCL_BREAK.
      */
 
+    nextRange = TclCreateExceptRange(LOOP_EXCEPTION_RANGE, envPtr);
+    envPtr->exceptAuxArrayPtr[nextRange].supportsContinue = 0;
     envPtr->currStackDepth = savedStackDepth;
     nextCodeOffset = ExceptionRangeStarts(envPtr, nextRange);
     SetLineInformation(3);
@@ -2444,6 +2513,8 @@ TclCompileForCmd(
 
     ExceptionRangeTarget(envPtr, bodyRange, breakOffset);
     ExceptionRangeTarget(envPtr, nextRange, breakOffset);
+    TclFinalizeLoopExceptionRange(envPtr, bodyRange);
+    TclFinalizeLoopExceptionRange(envPtr, nextRange);
 
     /*
      * The for command's result is an empty string.
@@ -2735,7 +2806,7 @@ CompileEachloopCmd(
      * Create an exception record to handle [break] and [continue].
      */
 
-    range = DeclareExceptionRange(envPtr, LOOP_EXCEPTION_RANGE);
+    range = TclCreateExceptRange(LOOP_EXCEPTION_RANGE, envPtr);
 
     /*
      * Evaluate then store each value list in the associated temporary.
@@ -2841,6 +2912,7 @@ CompileEachloopCmd(
      */
 
     ExceptionRangeTarget(envPtr, range, breakOffset);
+    TclFinalizeLoopExceptionRange(envPtr, range);
 
     /*
      * The command's result is an empty string if not collecting, or the
diff --git a/generic/tclCompCmdsSZ.c b/generic/tclCompCmdsSZ.c
index ed4d962..7831198 100644
--- a/generic/tclCompCmdsSZ.c
+++ b/generic/tclCompCmdsSZ.c
@@ -834,7 +834,7 @@ TclSubstCompile(
 	}
 
 	envPtr->line = bline;
-	catchRange = DeclareExceptionRange(envPtr, CATCH_EXCEPTION_RANGE);
+	catchRange = TclCreateExceptRange(CATCH_EXCEPTION_RANGE, envPtr);
 	OP4(	BEGIN_CATCH4, catchRange);
 	ExceptionRangeStarts(envPtr, catchRange);
 
@@ -1518,7 +1518,7 @@ IssueSwitchChainedTests(
 	 */
 
 	OP(	POP);
-	envPtr->currStackDepth = savedStackDepth + 1;
+	envPtr->currStackDepth = savedStackDepth;
 	envPtr->line = bodyLines[i+1];		/* TIP #280 */
 	envPtr->clNext = bodyContLines[i+1];	/* TIP #280 */
 	TclCompileCmdWord(interp, bodyToken[i+1], 1, envPtr);
@@ -2302,7 +2302,7 @@ IssueTryInstructions(
      * (and it's never called when there's a finally clause).
      */
 
-    range = DeclareExceptionRange(envPtr, CATCH_EXCEPTION_RANGE);
+    range = TclCreateExceptRange(CATCH_EXCEPTION_RANGE, envPtr);
     OP4(				BEGIN_CATCH4, range);
     ExceptionRangeStarts(envPtr, range);
     BODY(				bodyToken, 1);
@@ -2455,7 +2455,7 @@ IssueTryFinallyInstructions(
      * (if any trap matches) and run a finally clause.
      */
 
-    range = DeclareExceptionRange(envPtr, CATCH_EXCEPTION_RANGE);
+    range = TclCreateExceptRange(CATCH_EXCEPTION_RANGE, envPtr);
     OP4(				BEGIN_CATCH4, range);
     ExceptionRangeStarts(envPtr, range);
     envPtr->currStackDepth = savedStackDepth;
@@ -2522,7 +2522,7 @@ IssueTryFinallyInstructions(
 	     */
 
 	    if (resultVars[i] >= 0 || handlerTokens[i]) {
-		range = DeclareExceptionRange(envPtr, CATCH_EXCEPTION_RANGE);
+		range = TclCreateExceptRange(CATCH_EXCEPTION_RANGE, envPtr);
 		OP4(			BEGIN_CATCH4, range);
 		ExceptionRangeStarts(envPtr, range);
 	    }
@@ -2833,7 +2833,7 @@ TclCompileWhileCmd(
      * implement break and continue.
      */
 
-    range = DeclareExceptionRange(envPtr, LOOP_EXCEPTION_RANGE);
+    range = TclCreateExceptRange(LOOP_EXCEPTION_RANGE, envPtr);
 
     /*
      * Jump to the evaluation of the condition. This code uses the "loop
@@ -2869,6 +2869,10 @@ TclCompileWhileCmd(
 
     SetLineInformation(2);
     bodyCodeOffset = ExceptionRangeStarts(envPtr, range);
+    if (!loopMayEnd) {
+	envPtr->exceptArrayPtr[range].continueOffset = testCodeOffset;
+	envPtr->exceptArrayPtr[range].codeOffset = bodyCodeOffset;
+    }
     CompileBody(envPtr, bodyTokenPtr, interp);
     ExceptionRangeEnds(envPtr, range);
     envPtr->currStackDepth = savedStackDepth + 1;
@@ -2913,6 +2917,7 @@ TclCompileWhileCmd(
     envPtr->exceptArrayPtr[range].continueOffset = testCodeOffset;
     envPtr->exceptArrayPtr[range].codeOffset = bodyCodeOffset;
     ExceptionRangeTarget(envPtr, range, breakOffset);
+    TclFinalizeLoopExceptionRange(envPtr, range);
 
     /*
      * The while command's result is an empty string.
diff --git a/generic/tclCompile.c b/generic/tclCompile.c
index 039a694..f2e9329 100644
--- a/generic/tclCompile.c
+++ b/generic/tclCompile.c
@@ -745,7 +745,9 @@ TclSetByteCodeFromAny(
 	}
 	compEnv.atCmdStart = 2;		/* The disabling magic. */
 	TclCompileScript(interp, stringPtr, length, &compEnv);
+	assert (compEnv.atCmdStart > 1);
 	TclEmitOpcode(INST_DONE, &compEnv);
+	assert (compEnv.atCmdStart > 1);
     }
 
     /*
@@ -1084,9 +1086,11 @@ IsCompactibleCompileEnv(
 	case INST_NSUPVAR:
 	case INST_VARIABLE:
 	    return 0;
+	default:
+	    size = tclInstructionTable[*pc].numBytes;
+	    assert (size > 0);
+	    break;
 	}
-	size = tclInstructionTable[*pc].numBytes;
-	assert (size > 0);
     }
 
     return 1;
@@ -1145,31 +1149,39 @@ PeepholeOptimize(
 		(void) Tcl_CreateHashEntry(&targets, (void *) target, &isNew);
 	    }
 	    break;
+	case INST_START_CMD:
+	    assert (envPtr->atCmdStart < 2);
 	}
     }
 
     /*
-     * Replace PUSH/POP sequences (when non-hazardous) with NOPs.
+     * Replace PUSH/POP sequences (when non-hazardous) with NOPs. Also replace
+     * PUSH empty/CONCAT and TRY_CVT_NUMERIC (when followed by an operation
+     * that guarantees the check for arithmeticity).
      */
 
     (void) Tcl_CreateHashEntry(&targets, (void *) pc, &isNew);
     for (pc = envPtr->codeStart ; pc < envPtr->codeNext ; pc += size) {
-	int blank = 0, i;
+	int blank = 0, i, inst;
 
 	size = tclInstructionTable[*pc].numBytes;
 	prev2 = prev1;
 	prev1 = pc;
+	while (*(pc+size) == INST_NOP) {
+	    if (Tcl_FindHashEntry(&targets, (void *) (pc + size))) {
+		break;
+	    }
+	    size += tclInstructionTable[INST_NOP].numBytes;
+	}
 	if (Tcl_FindHashEntry(&targets, (void *) (pc + size))) {
 	    continue;
 	}
+	inst = *(pc + size);
 	switch (*pc) {
 	case INST_PUSH1:
-	    while (*(pc+size) == INST_NOP) {
-		size++;
-	    }
-	    if (*(pc+size) == INST_POP) {
-		blank = size + 1;
-	    } else if (*(pc+size) == INST_CONCAT1
+	    if (inst == INST_POP) {
+		blank = size + tclInstructionTable[inst].numBytes;
+	    } else if (inst == INST_CONCAT1
 		    && TclGetUInt1AtPtr(pc + size + 1) == 2) {
 		Tcl_Obj *litPtr = TclFetchLiteral(envPtr,
 			TclGetUInt1AtPtr(pc + 1));
@@ -1177,17 +1189,14 @@ PeepholeOptimize(
 
 		(void) Tcl_GetStringFromObj(litPtr, &numBytes);
 		if (numBytes == 0) {
-		    blank = size + 2;
+		    blank = size + tclInstructionTable[inst].numBytes;
 		}
 	    }
 	    break;
 	case INST_PUSH4:
-	    while (*(pc+size) == INST_NOP) {
-		size++;
-	    }
-	    if (*(pc+size) == INST_POP) {
+	    if (inst == INST_POP) {
 		blank = size + 1;
-	    } else if (*(pc+size) == INST_CONCAT1
+	    } else if (inst == INST_CONCAT1
 		    && TclGetUInt1AtPtr(pc + size + 1) == 2) {
 		Tcl_Obj *litPtr = TclFetchLiteral(envPtr,
 			TclGetUInt4AtPtr(pc + 1));
@@ -1195,10 +1204,49 @@ PeepholeOptimize(
 
 		(void) Tcl_GetStringFromObj(litPtr, &numBytes);
 		if (numBytes == 0) {
-		    blank = size + 2;
+		    blank = size + tclInstructionTable[inst].numBytes;
 		}
 	    }
 	    break;
+	case INST_TRY_CVT_TO_NUMERIC:
+	    switch (inst) {
+	    case INST_JUMP_TRUE1:
+	    case INST_JUMP_TRUE4:
+	    case INST_JUMP_FALSE1:
+	    case INST_JUMP_FALSE4:
+	    case INST_INCR_SCALAR1:
+	    case INST_INCR_ARRAY1:
+	    case INST_INCR_ARRAY_STK:
+	    case INST_INCR_SCALAR_STK:
+	    case INST_INCR_STK:
+	    case INST_LOR:
+	    case INST_LAND:
+	    case INST_EQ:
+	    case INST_NEQ:
+	    case INST_LT:
+	    case INST_LE:
+	    case INST_GT:
+	    case INST_GE:
+	    case INST_MOD:
+	    case INST_LSHIFT:
+	    case INST_RSHIFT:
+	    case INST_BITOR:
+	    case INST_BITXOR:
+	    case INST_BITAND:
+	    case INST_EXPON:
+	    case INST_ADD:
+	    case INST_SUB:
+	    case INST_DIV:
+	    case INST_MULT:
+	    case INST_LNOT:
+	    case INST_BITNOT:
+	    case INST_UMINUS:
+	    case INST_UPLUS:
+	    case INST_TRY_CVT_TO_NUMERIC:
+		blank = size;
+		break;
+	    }
+	    break;
 	}
 	if (blank > 0) {
 	    for (i=0 ; i<blank ; i++) {
@@ -1466,6 +1514,7 @@ TclInitCompileEnv(
     envPtr->mallocedLiteralArray = 0;
 
     envPtr->exceptArrayPtr = envPtr->staticExceptArraySpace;
+    envPtr->exceptAuxArrayPtr = envPtr->staticExAuxArraySpace;
     envPtr->exceptArrayNext = 0;
     envPtr->exceptArrayEnd = COMPILEENV_INIT_EXCEPT_RANGES;
     envPtr->mallocedExceptArray = 0;
@@ -1474,6 +1523,7 @@ TclInitCompileEnv(
     envPtr->cmdMapEnd = COMPILEENV_INIT_CMD_MAP_SIZE;
     envPtr->mallocedCmdMap = 0;
     envPtr->atCmdStart = 1;
+    envPtr->expandCount = 0;
 
     /*
      * TIP #280: Set up the extended command location information, based on
@@ -1678,6 +1728,7 @@ TclFreeCompileEnv(
     }
     if (envPtr->mallocedExceptArray) {
 	ckfree(envPtr->exceptArrayPtr);
+	ckfree(envPtr->exceptAuxArrayPtr);
     }
     if (envPtr->mallocedCmdMap) {
 	ckfree(envPtr->cmdMapPtr);
@@ -2010,6 +2061,7 @@ TclCompileScript(
 
 	    if (expand) {
 		TclEmitOpcode(INST_EXPAND_START, envPtr);
+		envPtr->expandCount++;
 	    }
 
 	    /*
@@ -2229,6 +2281,7 @@ TclCompileScript(
 		 */
 
 		TclEmitOpcode(INST_INVOKE_EXPANDED, envPtr);
+		envPtr->expandCount--;
 		TclAdjustStackDepth(1 - wordIdx, envPtr);
 	    } else if (wordIdx > 0) {
 		/*
@@ -3360,6 +3413,7 @@ TclCreateExceptRange(
 				 * new ExceptionRange structure. */
 {
     register ExceptionRange *rangePtr;
+    register ExceptionAux *auxPtr;
     int index = envPtr->exceptArrayNext;
 
     if (index >= envPtr->exceptArrayEnd) {
@@ -3371,12 +3425,16 @@ TclCreateExceptRange(
 
 	size_t currBytes =
 		envPtr->exceptArrayNext * sizeof(ExceptionRange);
+	size_t currBytes2 = envPtr->exceptArrayNext * sizeof(ExceptionAux);
 	int newElems = 2*envPtr->exceptArrayEnd;
 	size_t newBytes = newElems * sizeof(ExceptionRange);
+	size_t newBytes2 = newElems * sizeof(ExceptionAux);
 
 	if (envPtr->mallocedExceptArray) {
 	    envPtr->exceptArrayPtr =
 		    ckrealloc(envPtr->exceptArrayPtr, newBytes);
+	    envPtr->exceptAuxArrayPtr =
+		    ckrealloc(envPtr->exceptAuxArrayPtr, newBytes2);
 	} else {
 	    /*
 	     * envPtr->exceptArrayPtr isn't a ckalloc'd pointer, so we must
@@ -3384,9 +3442,12 @@ TclCreateExceptRange(
 	     */
 
 	    ExceptionRange *newPtr = ckalloc(newBytes);
+	    ExceptionAux *newPtr2 = ckalloc(newBytes2);
 
 	    memcpy(newPtr, envPtr->exceptArrayPtr, currBytes);
+	    memcpy(newPtr2, envPtr->exceptAuxArrayPtr, currBytes2);
 	    envPtr->exceptArrayPtr = newPtr;
+	    envPtr->exceptAuxArrayPtr = newPtr2;
 	    envPtr->mallocedExceptArray = 1;
 	}
 	envPtr->exceptArrayEnd = newElems;
@@ -3401,10 +3462,200 @@ TclCreateExceptRange(
     rangePtr->breakOffset = -1;
     rangePtr->continueOffset = -1;
     rangePtr->catchOffset = -1;
+    auxPtr = &envPtr->exceptAuxArrayPtr[index];
+    auxPtr->supportsContinue = 1;
+    auxPtr->stackDepth = envPtr->currStackDepth;
+    auxPtr->expandTarget = envPtr->expandCount;
+    auxPtr->numBreakTargets = 0;
+    auxPtr->breakTargets = NULL;
+    auxPtr->allocBreakTargets = 0;
+    auxPtr->numContinueTargets = 0;
+    auxPtr->continueTargets = NULL;
+    auxPtr->allocContinueTargets = 0;
     return index;
 }
 
 /*
+ * ---------------------------------------------------------------------
+ *
+ * TclGetInnermostExceptionRange --
+ *
+ *	Returns the innermost exception range that covers the current code
+ *	creation point, and (optionally) the stack depth that is expected at
+ *	that point. Relies on the fact that the range has a numCodeBytes = -1
+ *	when it is being populated and that inner ranges come after outer
+ *	ranges.
+ *
+ * ---------------------------------------------------------------------
+ */
+
+ExceptionRange *
+TclGetInnermostExceptionRange(
+    CompileEnv *envPtr,
+    int returnCode,
+    ExceptionAux **auxPtrPtr)
+{
+    int exnIdx = -1, i;
+
+    for (i=0 ; i<envPtr->exceptArrayNext ; i++) {
+	ExceptionRange *rangePtr = &envPtr->exceptArrayPtr[i];
+
+	if (CurrentOffset(envPtr) >= rangePtr->codeOffset &&
+		(rangePtr->numCodeBytes == -1 || CurrentOffset(envPtr) <
+			rangePtr->codeOffset+rangePtr->numCodeBytes) &&
+		(returnCode != TCL_CONTINUE ||
+			envPtr->exceptAuxArrayPtr[i].supportsContinue)) {
+	    exnIdx = i;
+	}
+    }
+    if (exnIdx == -1) {
+	return NULL;
+    }
+    if (auxPtrPtr) {
+	*auxPtrPtr = &envPtr->exceptAuxArrayPtr[exnIdx];
+    }
+    return &envPtr->exceptArrayPtr[exnIdx];
+}
+
+/*
+ * ---------------------------------------------------------------------
+ *
+ * TclAddLoopBreakFixup, TclAddLoopContinueFixup --
+ *
+ *	Adds a place that wants to break/continue to the loop exception range
+ *	tracking that will be fixed up once the loop can be finalized. These
+ *	functions will generate an INST_JUMP4 that will be fixed up during the
+ *	loop finalization.
+ *
+ * ---------------------------------------------------------------------
+ */
+
+void
+TclAddLoopBreakFixup(
+    CompileEnv *envPtr,
+    ExceptionAux *auxPtr)
+{
+    int range = auxPtr - envPtr->exceptAuxArrayPtr;
+
+    if (envPtr->exceptArrayPtr[range].type != LOOP_EXCEPTION_RANGE) {
+	Tcl_Panic("trying to add 'break' fixup to full exception range");
+    }
+
+    if (++auxPtr->numBreakTargets > auxPtr->allocBreakTargets) {
+	auxPtr->allocBreakTargets *= 2;
+	auxPtr->allocBreakTargets += 2;
+	if (auxPtr->breakTargets) {
+	    auxPtr->breakTargets = ckrealloc(auxPtr->breakTargets,
+		    sizeof(int) * auxPtr->allocBreakTargets);
+	} else {
+	    auxPtr->breakTargets =
+		    ckalloc(sizeof(int) * auxPtr->allocBreakTargets);
+	}
+    }
+    auxPtr->breakTargets[auxPtr->numBreakTargets - 1] = CurrentOffset(envPtr);
+    TclEmitInstInt4(INST_JUMP4, 0, envPtr);
+}
+
+void
+TclAddLoopContinueFixup(
+    CompileEnv *envPtr,
+    ExceptionAux *auxPtr)
+{
+    int range = auxPtr - envPtr->exceptAuxArrayPtr;
+
+    if (envPtr->exceptArrayPtr[range].type != LOOP_EXCEPTION_RANGE) {
+	Tcl_Panic("trying to add 'continue' fixup to full exception range");
+    }
+
+    if (++auxPtr->numContinueTargets > auxPtr->allocContinueTargets) {
+	auxPtr->allocContinueTargets *= 2;
+	auxPtr->allocContinueTargets += 2;
+	if (auxPtr->continueTargets) {
+	    auxPtr->continueTargets = ckrealloc(auxPtr->continueTargets,
+		    sizeof(int) * auxPtr->allocContinueTargets);
+	} else {
+	    auxPtr->continueTargets =
+		    ckalloc(sizeof(int) * auxPtr->allocContinueTargets);
+	}
+    }
+    auxPtr->continueTargets[auxPtr->numContinueTargets - 1] =
+	    CurrentOffset(envPtr);
+    TclEmitInstInt4(INST_JUMP4, 0, envPtr);
+}
+
+/*
+ * ---------------------------------------------------------------------
+ *
+ * TclFinalizeLoopExceptionRange --
+ *
+ *	Finalizes a loop exception range, binding the registered [break] and
+ *	[continue] implementations so that they jump to the correct place.
+ *	Note that this must only be called after *all* the exception range
+ *	target offsets have been set.
+ *
+ * ---------------------------------------------------------------------
+ */
+
+void
+TclFinalizeLoopExceptionRange(
+    CompileEnv *envPtr,
+    int range)
+{
+    ExceptionRange *rangePtr = &envPtr->exceptArrayPtr[range];
+    ExceptionAux *auxPtr = &envPtr->exceptAuxArrayPtr[range];
+    int i, offset;
+    unsigned char *site;
+
+    if (rangePtr->type != LOOP_EXCEPTION_RANGE) {
+	Tcl_Panic("trying to finalize a loop exception range");
+    }
+
+    /*
+     * Do the jump fixups. Note that these are always issued as INST_JUMP4 so
+     * there is no need to fuss around with updating code offsets.
+     */
+
+    for (i=0 ; i<auxPtr->numBreakTargets ; i++) {
+	site = envPtr->codeStart + auxPtr->breakTargets[i];
+	offset = rangePtr->breakOffset - auxPtr->breakTargets[i];
+	TclUpdateInstInt4AtPc(INST_JUMP4, offset, site);
+    }
+    for (i=0 ; i<auxPtr->numContinueTargets ; i++) {
+	site = envPtr->codeStart + auxPtr->continueTargets[i];
+	if (rangePtr->continueOffset == -1) {
+	    int j;
+
+	    /*
+	     * WTF? Can't bind, so revert to an INST_CONTINUE.
+	     */
+
+	    *site = INST_CONTINUE;
+	    for (j=0 ; j<4 ; j++) {
+		*++site = INST_NOP;
+	    }
+	} else {
+	    offset = rangePtr->continueOffset - auxPtr->continueTargets[i];
+	    TclUpdateInstInt4AtPc(INST_JUMP4, offset, site);
+	}
+    }
+
+    /*
+     * Drop the arrays we were holding the only reference to.
+     */
+
+    if (auxPtr->breakTargets) {
+	ckfree(auxPtr->breakTargets);
+	auxPtr->breakTargets = NULL;
+	auxPtr->numBreakTargets = 0;
+    }
+    if (auxPtr->continueTargets) {
+	ckfree(auxPtr->continueTargets);
+	auxPtr->continueTargets = NULL;
+	auxPtr->numContinueTargets = 0;
+    }
+}
+
+/*
  *----------------------------------------------------------------------
  *
  * TclCreateAuxData --
@@ -3764,6 +4015,22 @@ TclFixupForwardJump(
 	}
     }
 
+    for (k = 0 ; k < envPtr->exceptArrayNext ; k++) {
+	ExceptionAux *auxPtr = &envPtr->exceptAuxArrayPtr[k];
+	int i;
+
+	for (i=0 ; i<auxPtr->numBreakTargets ; i++) {
+	    if (jumpFixupPtr->codeOffset < auxPtr->breakTargets[i]) {
+		auxPtr->breakTargets[i] += 3;
+	    }
+	}
+	for (i=0 ; i<auxPtr->numContinueTargets ; i++) {
+	    if (jumpFixupPtr->codeOffset < auxPtr->continueTargets[i]) {
+		auxPtr->continueTargets[i] += 3;
+	    }
+	}
+    }
+
     /*
      * TIP #280: Adjust the mapping from PC values to the per-command
      * information about arguments and their line numbers.
diff --git a/generic/tclCompile.h b/generic/tclCompile.h
index 0be5d1d..957c724 100644
--- a/generic/tclCompile.h
+++ b/generic/tclCompile.h
@@ -100,6 +100,49 @@ typedef struct ExceptionRange {
 } ExceptionRange;
 
 /*
+ * Auxiliary data used when issuing (currently just loop) exception ranges,
+ * but which is not required during execution.
+ */
+
+typedef struct ExceptionAux {
+    int supportsContinue;	/* Whether this exception range will have a
+				 * continueOffset created for it; if it is a
+				 * loop exception range that *doesn't* have
+				 * one (see [for] next-clause) then we must
+				 * not pick up the range when scanning for a
+				 * target to continue to. */
+    int stackDepth;		/* The stack depth at the point where the
+				 * exception range was created. This is used
+				 * to calculate the number of POPs required to
+				 * restore the stack to its prior state. */
+    int expandTarget;		/* The number of expansions expected on the
+				 * auxData stack at the time the loop starts;
+				 * we can't currently discard them except by
+				 * doing INST_INVOKE_EXPANDED; this is a known
+				 * problem. */
+    int numBreakTargets;	/* The number of [break]s that want to be
+				 * targeted to the place where this loop
+				 * exception will be bound to. */
+    int *breakTargets;		/* The offsets of the INST_JUMP4 instructions
+				 * issued by the [break]s that we must
+				 * update. Note that resizing a jump (via
+				 * TclFixupForwardJump) can cause the contents
+				 * of this array to be updated. When
+				 * numBreakTargets==0, this is NULL. */
+    int allocBreakTargets;	/* The size of the breakTargets array. */
+    int numContinueTargets;	/* The number of [continue]s that want to be
+				 * targeted to the place where this loop
+				 * exception will be bound to. */
+    int *continueTargets;	/* The offsets of the INST_JUMP4 instructions
+				 * issued by the [continue]s that we must
+				 * update. Note that resizing a jump (via
+				 * TclFixupForwardJump) can cause the contents
+				 * of this array to be updated. When
+				 * numContinueTargets==0, this is NULL. */
+    int allocContinueTargets;	/* The size of the continueTargets array. */
+} ExceptionAux;
+
+/*
  * Structure used to map between instruction pc and source locations. It
  * defines for each compiled Tcl command its code's starting offset and its
  * source's starting offset and length. Note that the code offset increases
@@ -275,6 +318,11 @@ typedef struct CompileEnv {
 				 * entry. */
     int mallocedExceptArray;	/* 1 if ExceptionRange array was expanded and
 				 * exceptArrayPtr points in heap, else 0. */
+    ExceptionAux *exceptAuxArrayPtr;
+				/* Array of information used to restore the
+				 * state when processing BREAK/CONTINUE
+				 * exceptions. Must be the same size as the
+				 * exceptArrayPtr. */
     CmdLocation *cmdMapPtr;	/* Points to start of CmdLocation array.
 				 * numCommands is the index of the next entry
 				 * to use; (numCommands-1) is the entry index
@@ -296,6 +344,9 @@ typedef struct CompileEnv {
 				/* Initial storage of LiteralEntry array. */
     ExceptionRange staticExceptArraySpace[COMPILEENV_INIT_EXCEPT_RANGES];
 				/* Initial ExceptionRange array storage. */
+    ExceptionAux staticExAuxArraySpace[COMPILEENV_INIT_EXCEPT_RANGES];
+				/* Initial static except auxiliary info array
+				 * storage. */
     CmdLocation staticCmdMapSpace[COMPILEENV_INIT_CMD_MAP_SIZE];
 				/* Initial storage for cmd location map. */
     AuxData staticAuxDataArraySpace[COMPILEENV_INIT_AUX_DATA_SIZE];
@@ -312,6 +363,10 @@ typedef struct CompileEnv {
 				 * inefficient. If set to 2, that instruction
 				 * should not be issued at all (by the generic
 				 * part of the command compiler). */
+    int expandCount;		/* Number of INST_EXPAND_START instructions
+				 * encountered that have not yet been paired
+				 * with a corresponding
+				 * INST_INVOKE_EXPANDED. */
     ContLineLoc *clLoc;		/* If not NULL, the table holding the
 				 * locations of the invisible continuation
 				 * lines in the input script, to adjust the
@@ -984,6 +1039,14 @@ MODULE_SCOPE void	TclInitCompileEnv(Tcl_Interp *interp,
 			    int numBytes, const CmdFrame *invoker, int word);
 MODULE_SCOPE void	TclInitJumpFixupArray(JumpFixupArray *fixupArrayPtr);
 MODULE_SCOPE void	TclInitLiteralTable(LiteralTable *tablePtr);
+MODULE_SCOPE ExceptionRange *TclGetInnermostExceptionRange(CompileEnv *envPtr,
+			    int returnCode, ExceptionAux **auxPtrPtr);
+MODULE_SCOPE void	TclAddLoopBreakFixup(CompileEnv *envPtr,
+			    ExceptionAux *auxPtr);
+MODULE_SCOPE void	TclAddLoopContinueFixup(CompileEnv *envPtr,
+			    ExceptionAux *auxPtr);
+MODULE_SCOPE void	TclFinalizeLoopExceptionRange(CompileEnv *envPtr,
+			    int range);
 #ifdef TCL_COMPILE_STATS
 MODULE_SCOPE char *	TclLiteralStats(LiteralTable *tablePtr);
 MODULE_SCOPE int	TclLog2(int value);
@@ -1398,14 +1461,11 @@ MODULE_SCOPE Tcl_Obj	*TclNewInstNameObj(unsigned char inst);
  * of LOOP ranges is an interesting datum for debugging purposes, and that is
  * what we compute now.
  *
- * static int	DeclareExceptionRange(CompileEnv *envPtr, int type);
  * static int	ExceptionRangeStarts(CompileEnv *envPtr, int index);
  * static void	ExceptionRangeEnds(CompileEnv *envPtr, int index);
  * static void	ExceptionRangeTarget(CompileEnv *envPtr, int index, LABEL);
  */
 
-#define DeclareExceptionRange(envPtr, type) \
-    (TclCreateExceptRange((type), (envPtr)))
 #define ExceptionRangeStarts(envPtr, index) \
     (((envPtr)->exceptDepth++),						\
     ((envPtr)->maxExceptDepth =						\
diff --git a/tests/for.test b/tests/for.test
index ff4dc0e..3f4d2b7 100644
--- a/tests/for.test
+++ b/tests/for.test
@@ -14,6 +14,12 @@ if {[lsearch [namespace children] ::tcltest] == -1} {
     namespace import -force ::tcltest::*
 }
 
+# Used for constraining memory leak tests
+testConstraint memory [llength [info commands memory]]
+if {[testConstraint memory]} {
+    proc meminfo {} {lindex [split [memory info] "\n"] 3 3}
+}
+
 # Basic "for" operation.
 
 test for-1.1 {TclCompileForCmd: missing initial command} {
@@ -345,7 +351,6 @@ proc formatMail {} {
         64 {        UNIX (Solaris 2.* and SunOS, other systems soon to follow). Easy to install} \
         65 {     binary packages are now for sale at the Sun Labs Tcl/Tk Shop. Check it out!} \
     }
-
     set result ""
     set NL "
 "
@@ -365,7 +370,6 @@ proc formatMail {} {
     } else {
 	set break 1
     }
-
     set xmailer 0
     set inheaders 1
     set last [array size lines]
@@ -386,9 +390,7 @@ proc formatMail {} {
 	    set limit 55
 	} else {
 	    set limit 55
-
 	    # Decide whether or not to break the body line
-
 	    if {$plen > 0} {
 		if {[string first {> } $line] == 0} {
 		    # This is quoted text from previous message, don't reformat
@@ -431,7 +433,7 @@ proc formatMail {} {
 	set climit [expr $limit-1]
 	set cutoff 50
 	set continuation 0
-	
+
 	while {[string length $line] > $limit} {
 	    for {set c [expr $limit-1]} {$c >= $cutoff} {incr c -1} {
 		set char [string index $line $c]
@@ -824,7 +826,67 @@ test for-6.18 {Tcl_ForObjCmd: for command result} {
     1 {invoked "continue" outside of a loop} \
     ]
 
-
+test for-7.1 {Bug 3614226: ensure that break cleans up the stack} memory {
+    apply {{} {
+	# Can't use [memtest]; must be careful when we change stack frames
+	set end [meminfo]
+	for {set i 0} {$i < 5} {incr i} {
+	    for {set x 0} {$x < 5} {incr x} {
+		list a b c [break] d e f
+	    }
+	    set tmp $end
+	    set end [meminfo]
+	}
+	expr {$end - $tmp}
+    }}
+} 0
+test for-7.2 {Bug 3614226: ensure that continue cleans up the stack} memory {
+    apply {{} {
+	# Can't use [memtest]; must be careful when we change stack frames
+	set end [meminfo]
+	for {set i 0} {$i < 5} {incr i} {
+	    for {set x 0} {$x < 5} {incr x} {
+		list a b c [continue] d e f
+	    }
+	    set tmp $end
+	    set end [meminfo]
+	}
+	expr {$end - $tmp}
+    }}
+} 0
+test for-7.3 {Bug 3614226: ensure that break cleans up the expansion stack} {memory knownBug} {
+    apply {{} {
+	# Can't use [memtest]; must be careful when we change stack frames
+	set end [meminfo]
+	for {set i 0} {$i < 5} {incr i} {
+	    for {set x 0} {[incr x]<50} {} {
+		puts {*}[puts a b c {*}[break] d e f]
+	    }
+	    set tmp $end
+	    set end [meminfo]
+	}
+	expr {$end - $tmp}
+    }}
+} 0
+test for-7.4 {Bug 3614226: ensure that continue cleans up the expansion stack} {memory knownBug} {
+    apply {{} {
+	# Can't use [memtest]; must be careful when we change stack frames
+	set end [meminfo]
+	for {set i 0} {$i < 5} {incr i} {
+	    for {set x 0} {[incr x]<50} {} {
+		puts {*}[puts a b c {*}[continue] d e f]
+	    }
+	    set tmp $end
+	    set end [meminfo]
+	}
+	expr {$end - $tmp}
+    }}
+} 0
+
 # cleanup
 ::tcltest::cleanupTests
 return
+
+# Local Variables:
+# mode: tcl
+# End: