Rewrite of the TclCompileScript() routine.

Primarily this breaks that large, rather convoluted routine into many
smaller more single-purpose routines for greater clarity.  This also
permits more sharing of function components.  Ensemble compiles now share
the same low level routines as top-level command compiles.  This refactoring
should also have the benefit of easing merging between branches by better
locating patches according to what function or data structure they tweak.

Also in this checkin:
    Minimized calls to Tcl_ResetResult() during compile.
    Several commands compile their detected syntax errors into
	bytecode that reports the syntax error.
    Significant reform to the TIP 280 machinery, including elimination
	of the litInfo hash table.  Its function of finding the index
	of a compiled command in a script from a pc value has been redone
	using the codeDelta information already stored in ByteCode.

1 files changed, 38 insertions, 24 deletions

diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index d3a0d32..f8ed667 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -721,7 +721,7 @@ static ExceptionRange *	GetExceptRangeForPc(const unsigned char *pc,
 			    int catchOnly, ByteCode *codePtr);
 static const char *	GetSrcInfoForPc(const unsigned char *pc,
 			    ByteCode *codePtr, int *lengthPtr,
-			    const unsigned char **pcBeg);
+			    const unsigned char **pcBeg, int *cmdIdxPtr);
 static Tcl_Obj **	GrowEvaluationStack(ExecEnv *eePtr, int growth,
 			    int move);
 static void		IllegalExprOperandType(Tcl_Interp *interp,
@@ -1426,17 +1426,12 @@ Tcl_NRExprObj(
     Tcl_Obj *resultPtr)
 {
     ByteCode *codePtr;
+    Tcl_InterpState state = Tcl_SaveInterpState(interp, TCL_OK);
 
-    /* TODO: consider saving whole state? */
-    Tcl_Obj *saveObjPtr = Tcl_GetObjResult(interp);
-
-    Tcl_IncrRefCount(saveObjPtr);
-
+    Tcl_ResetResult(interp);
     codePtr = CompileExprObj(interp, objPtr);
 
-    /* TODO: Confirm reset not required? */
-    /*Tcl_ResetResult(interp);*/
-    Tcl_NRAddCallback(interp, ExprObjCallback, saveObjPtr, resultPtr,
+    Tcl_NRAddCallback(interp, ExprObjCallback, state, resultPtr,
 	    NULL, NULL);
     return TclNRExecuteByteCode(interp, codePtr);
 }
@@ -1447,14 +1442,15 @@ ExprObjCallback(
     Tcl_Interp *interp,
     int result)
 {
-    Tcl_Obj *saveObjPtr = data[0];
+    Tcl_InterpState state = data[0];
     Tcl_Obj *resultPtr = data[1];
 
     if (result == TCL_OK) {
 	TclSetDuplicateObj(resultPtr, Tcl_GetObjResult(interp));
-	Tcl_SetObjResult(interp, saveObjPtr);
+	(void) Tcl_RestoreInterpState(interp, state);
+    } else {
+	Tcl_DiscardInterpState(state);
     }
-    TclDecrRefCount(saveObjPtr);
     return result;
 }
 
@@ -2435,8 +2431,11 @@ TEBCresume(
 	iPtr->cmdFramePtr = bcFramePtr;
 
 	if (iPtr->flags & INTERP_DEBUG_FRAME) {
-	    TclArgumentBCEnter((Tcl_Interp *) iPtr, objv, objc,
-		    codePtr, bcFramePtr, pc - codePtr->codeStart);
+	    int cmd;
+	    if (GetSrcInfoForPc(pc, codePtr, NULL, NULL, &cmd)) {
+		TclArgumentBCEnter((Tcl_Interp *) iPtr, objv, objc,
+			codePtr, bcFramePtr, cmd, pc - codePtr->codeStart);
+	    }
 	}
 
 	pc++;
@@ -2889,8 +2888,11 @@ TEBCresume(
 	iPtr->cmdFramePtr = bcFramePtr;
 
 	if (iPtr->flags & INTERP_DEBUG_FRAME) {
-	    TclArgumentBCEnter((Tcl_Interp *) iPtr, objv, objc,
-		    codePtr, bcFramePtr, pc - codePtr->codeStart);
+	    int cmd;
+	    if (GetSrcInfoForPc(pc, codePtr, NULL, NULL, &cmd)) {
+		TclArgumentBCEnter((Tcl_Interp *) iPtr, objv, objc,
+			codePtr, bcFramePtr, cmd, pc - codePtr->codeStart);
+	    }
 	}
 
 	DECACHE_STACK_INFO();
@@ -3035,8 +3037,11 @@ TEBCresume(
 	bcFramePtr->data.tebc.pc = (char *) pc;
 	iPtr->cmdFramePtr = bcFramePtr;
 	if (iPtr->flags & INTERP_DEBUG_FRAME) {
-	    TclArgumentBCEnter((Tcl_Interp *) iPtr, objv, objc,
-		    codePtr, bcFramePtr, pc - codePtr->codeStart);
+	    int cmd;
+	    if (GetSrcInfoForPc(pc, codePtr, NULL, NULL, &cmd)) {
+		TclArgumentBCEnter((Tcl_Interp *) iPtr, objv, objc,
+			codePtr, bcFramePtr, cmd, pc - codePtr->codeStart);
+	    }
 	}
 	iPtr->ensembleRewrite.sourceObjs = objv;
 	iPtr->ensembleRewrite.numRemovedObjs = opnd;
@@ -6971,7 +6976,7 @@ TEBCresume(
 	if ((result == TCL_ERROR) && !(iPtr->flags & ERR_ALREADY_LOGGED)) {
 	    const unsigned char *pcBeg;
 
-	    bytes = GetSrcInfoForPc(pc, codePtr, &length, &pcBeg);
+	    bytes = GetSrcInfoForPc(pc, codePtr, &length, &pcBeg, NULL);
 	    DECACHE_STACK_INFO();
 	    TclLogCommandInfo(interp, codePtr->source, bytes,
 		    bytes ? length : 0, pcBeg, tosPtr);
@@ -7153,7 +7158,7 @@ TEBCresume(
 	    }
 
 	    codePtr->flags |= TCL_BYTECODE_RECOMPILE;
-	    bytes = GetSrcInfoForPc(pc, codePtr, &length, NULL);
+	    bytes = GetSrcInfoForPc(pc, codePtr, &length, NULL, NULL);
 	    opnd = TclGetUInt4AtPtr(pc+1);
 	    pc += (opnd-1);
 	    PUSH_OBJECT(Tcl_NewStringObj(bytes, length));
@@ -8646,7 +8651,7 @@ ValidatePcAndStackTop(
     if (checkStack && 
 	    ((stackTop < 0) || (stackTop > stackUpperBound))) {
 	int numChars;
-	const char *cmd = GetSrcInfoForPc(pc, codePtr, &numChars, NULL);
+	const char *cmd = GetSrcInfoForPc(pc, codePtr, &numChars, NULL, NULL);
 
 	fprintf(stderr, "\nBad stack top %d at pc %u in TclNRExecuteByteCode (min 0, max %i)",
 		stackTop, relativePc, stackUpperBound);
@@ -8760,7 +8765,7 @@ TclGetSrcInfoForCmd(
     ByteCode *codePtr = (ByteCode *) cfPtr->data.tebc.codePtr;
 
     return GetSrcInfoForPc((unsigned char *) cfPtr->data.tebc.pc,
-	    codePtr, lenPtr, NULL);
+	    codePtr, lenPtr, NULL, NULL);
 }
 
 void
@@ -8772,7 +8777,7 @@ TclGetSrcInfoForPc(
     if (cfPtr->cmd.str.cmd == NULL) {
 	cfPtr->cmd.str.cmd = GetSrcInfoForPc(
 		(unsigned char *) cfPtr->data.tebc.pc, codePtr,
-		&cfPtr->cmd.str.len, NULL);
+		&cfPtr->cmd.str.len, NULL, NULL);
     }
 
     if (cfPtr->cmd.str.cmd != NULL) {
@@ -8832,9 +8837,12 @@ GetSrcInfoForPc(
     int *lengthPtr,		/* If non-NULL, the location where the length
 				 * of the command's source should be stored.
 				 * If NULL, no length is stored. */
-    const unsigned char **pcBeg)/* If non-NULL, the bytecode location
+    const unsigned char **pcBeg,/* If non-NULL, the bytecode location
 				 * where the current instruction starts.
 				 * If NULL; no pointer is stored. */
+    int *cmdIdxPtr)		/* If non-NULL, the location where the index
+				 * of the command containing the pc should 
+				 * be stored. */
 {
     register int pcOffset = (pc - codePtr->codeStart);
     int numCmds = codePtr->numCommands;
@@ -8844,6 +8852,7 @@ GetSrcInfoForPc(
     int bestDist = INT_MAX;	/* Distance of pc to best cmd's start pc. */
     int bestSrcOffset = -1;	/* Initialized to avoid compiler warning. */
     int bestSrcLength = -1;	/* Initialized to avoid compiler warning. */
+    int bestCmdIdx = -1;
 
     if ((pcOffset < 0) || (pcOffset >= codePtr->numCodeBytes)) {
 	if (pcBeg != NULL) *pcBeg = NULL;
@@ -8911,6 +8920,7 @@ GetSrcInfoForPc(
 		bestDist = dist;
 		bestSrcOffset = srcOffset;
 		bestSrcLength = srcLen;
+		bestCmdIdx = i;
 	    }
 	}
     }
@@ -8940,6 +8950,10 @@ GetSrcInfoForPc(
 	*lengthPtr = bestSrcLength;
     }
 
+    if (cmdIdxPtr != NULL) {
+	*cmdIdxPtr = bestCmdIdx;
+    }
+
     return (codePtr->source + bestSrcOffset);
 }