[Patch 2995655] Report inner contexts in [info errorstack]

7 files changed, 335 insertions, 25 deletions

diff --git a/generic/tclBasic.c b/generic/tclBasic.c
index f0d3e5d..fa63953 100644
--- a/generic/tclBasic.c
+++ b/generic/tclBasic.c
@@ -16,7 +16,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclBasic.c,v 1.467 2010/10/01 12:52:49 dkf Exp $
+ * RCS: @(#) $Id: tclBasic.c,v 1.468 2010/10/20 20:52:26 ferrieux Exp $
  */
 
 #include "tclInt.h"
@@ -549,6 +549,10 @@ Tcl_CreateInterp(void)
     Tcl_IncrRefCount(iPtr->upLiteral);
     TclNewLiteralStringObj(iPtr->callLiteral,"CALL");
     Tcl_IncrRefCount(iPtr->callLiteral);
+    TclNewLiteralStringObj(iPtr->innerLiteral,"INNER");
+    Tcl_IncrRefCount(iPtr->innerLiteral);
+    iPtr->innerContext = Tcl_NewListObj(0, NULL);
+    Tcl_IncrRefCount(iPtr->innerContext);
     iPtr->errorCode = NULL;
     TclNewLiteralStringObj(iPtr->ecVar, "::errorCode");
     Tcl_IncrRefCount(iPtr->ecVar);
@@ -1492,6 +1496,8 @@ DeleteInterpProc(
     iPtr->errorStack = NULL;
     Tcl_DecrRefCount(iPtr->upLiteral);
     Tcl_DecrRefCount(iPtr->callLiteral);
+    Tcl_DecrRefCount(iPtr->innerLiteral);
+    Tcl_DecrRefCount(iPtr->innerContext);
     if (iPtr->returnOpts) {
 	Tcl_DecrRefCount(iPtr->returnOpts);
     }
diff --git a/generic/tclCompCmds.c b/generic/tclCompCmds.c
index a5e1074..cfa6678 100644
--- a/generic/tclCompCmds.c
+++ b/generic/tclCompCmds.c
@@ -12,7 +12,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclCompCmds.c,v 1.170 2010/10/20 13:34:10 dkf Exp $
+ * RCS: @(#) $Id: tclCompCmds.c,v 1.171 2010/10/20 20:52:27 ferrieux Exp $
  */
 
 #include "tclInt.h"
@@ -3616,6 +3616,7 @@ TclCompileSyntaxError(
     int numBytes;
     const char *bytes = TclGetStringFromObj(msg, &numBytes);
 
+    TclErrorStackResetIf(interp, bytes, numBytes);
     TclEmitPush(TclRegisterNewLiteral(envPtr, bytes, numBytes), envPtr);
     CompileReturnInternal(envPtr, INST_SYNTAX, TCL_ERROR, 0,
 	    Tcl_GetReturnOptions(interp, TCL_ERROR));
diff --git a/generic/tclCompile.c b/generic/tclCompile.c
index 7781066..d40af69 100644
--- a/generic/tclCompile.c
+++ b/generic/tclCompile.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: tclCompile.c,v 1.192 2010/10/20 13:34:11 dkf Exp $
+ * RCS: @(#) $Id: tclCompile.c,v 1.193 2010/10/20 20:52:27 ferrieux Exp $
  */
 
 #include "tclInt.h"
@@ -452,6 +452,8 @@ static int		FormatInstruction(ByteCode *codePtr,
 			    const unsigned char *pc, Tcl_Obj *bufferObj);
 static void		PrintSourceToObj(Tcl_Obj *appendObj,
 			    const char *stringPtr, int maxChars);
+static void		UpdateStringOfInstName(Tcl_Obj *objPtr);
+
 /*
  * TIP #280: Helper for building the per-word line information of all compiled
  * commands.
@@ -486,6 +488,19 @@ static const Tcl_ObjType substCodeType = {
     NULL,			/* updateStringProc */
     NULL,			/* setFromAnyProc */
 };
+
+/*
+ * The structure below defines an instruction name Tcl object to allow
+ * reporting of inner contexts in errorstack without string allocation.
+ */
+
+static const Tcl_ObjType tclInstNameType = {
+    "instname",			/* name */
+    NULL,			/* freeIntRepProc */
+    NULL,			/* dupIntRepProc */
+    UpdateStringOfInstName,	/* updateStringProc */
+    NULL,			/* setFromAnyProc */
+};
 
 /*
  *----------------------------------------------------------------------
@@ -4238,6 +4253,165 @@ FormatInstruction(
 /*
  *----------------------------------------------------------------------
  *
+ * TclGetInnerContext --
+ *
+ *	If possible, returns a list capturing the inner context. Otherwise
+ *	return NULL.
+ *
+ *----------------------------------------------------------------------
+ */
+Tcl_Obj *TclGetInnerContext(Tcl_Interp *interp,
+			    const unsigned char *pc,
+			    Tcl_Obj **tosPtr)
+{
+    int objc = 0, off = 0;
+    Tcl_Obj *result;
+    Interp *iPtr = (Interp *) interp;
+
+    switch(*pc) {
+
+    case INST_STR_LEN:
+    case INST_LNOT:
+    case INST_BITNOT:
+    case INST_UMINUS:
+    case INST_UPLUS:
+    case INST_TRY_CVT_TO_NUMERIC:
+    case INST_EXPAND_STKTOP:
+    case INST_EXPR_STK:
+
+        objc = 1;
+        break;
+
+    case INST_LIST_IN:
+    case INST_LIST_NOT_IN:	/* Basic list containment operators. */
+    case INST_STR_EQ:
+    case INST_STR_NEQ:		/* String (in)equality check */
+    case INST_STR_CMP:		/* String compare. */
+    case INST_STR_INDEX:
+    case INST_STR_MATCH:
+    case INST_REGEXP:
+    case INST_EQ:
+    case INST_NEQ:
+    case INST_LT:
+    case INST_GT:
+    case INST_LE:
+    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:
+        objc = 2;
+        break;
+
+    case INST_RETURN_STK:
+        /* early pop. TODO: dig out opt dict too :/ */
+        objc = 1;
+        break;
+
+    case INST_SYNTAX:
+    case INST_RETURN_IMM:
+        objc = 2;
+        break;
+
+    case INST_INVOKE_STK4:
+	objc = TclGetUInt4AtPtr(pc+1);
+        break;
+
+    case INST_INVOKE_STK1:
+	objc = TclGetUInt1AtPtr(pc+1);
+	break;
+    }
+
+    result = iPtr->innerContext;
+    if (Tcl_IsShared(result)) {
+        Tcl_DecrRefCount(result);
+        iPtr->innerContext = result = Tcl_NewListObj(objc + 1, NULL);
+        Tcl_IncrRefCount(result);
+    } else {
+        int len;
+
+	Tcl_ListObjLength(interp, result, &len);
+        /* reset while keeping the list intrep as much as possible */
+        Tcl_ListObjReplace(interp, result, 0, len, 0, NULL);
+    }    
+    Tcl_ListObjAppendElement(NULL, result, TclNewInstNameObj(*pc));
+    for(;objc>0;objc--) {
+        Tcl_Obj *ob;
+
+        ob = tosPtr[1 - objc + off];
+        if (!ob) {
+            Tcl_Panic("InnerContext: bad tos -- appending null object");
+        }
+        if (ob->refCount<=0 || ob->refCount==0x61616161) {
+            Tcl_Panic("InnerContext: bad tos -- appending freed object %p",ob);
+        }
+        Tcl_ListObjAppendElement(NULL, result, ob);
+    }
+
+    return result;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclNewInstNameObj --
+ *
+ *	Creates a new InstName Tcl_Obj based on the given instruction
+ *
+ *----------------------------------------------------------------------
+ */
+MODULE_SCOPE Tcl_Obj	*TclNewInstNameObj(unsigned char inst)
+{
+    Tcl_Obj *objPtr;
+    
+    objPtr=Tcl_NewObj();
+    objPtr->typePtr = &tclInstNameType;
+    objPtr->internalRep.longValue = (long)inst;
+    objPtr->bytes = NULL;
+
+    return objPtr;
+}
+
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * UpdateStringOfInstName --
+ *
+ *	Update the string representation for an instruction name object.
+ *
+ *----------------------------------------------------------------------
+ */
+static void UpdateStringOfInstName(Tcl_Obj *objPtr)
+{
+    int inst = objPtr->internalRep.longValue;
+    char *s,buf[20];
+    int len;
+
+    if ((inst < 0) || (inst > LAST_INST_OPCODE)) {
+
+        sprintf(buf, "inst_%d", inst);
+        s = buf;
+    } else {
+        s = (char *)tclInstructionTable[objPtr->internalRep.longValue].name;
+    }
+    len = strlen(s);
+    objPtr->bytes = ckalloc((unsigned) len + 1);
+    strcpy(objPtr->bytes, s);
+    objPtr->length = len;
+}
+
+
+/*
+ *----------------------------------------------------------------------
+ *
  * PrintSourceToObj --
  *
  *	Appends a quoted representation of a string to a Tcl_Obj.
@@ -4343,5 +4517,7 @@ RecordByteCodeStats(
  * mode: c
  * c-basic-offset: 4
  * fill-column: 78
+ * tab-width: 8
+ * indent-tabs-mode: nil
  * End:
  */
diff --git a/generic/tclCompile.h b/generic/tclCompile.h
index e6b0411..0df13d9 100644
--- a/generic/tclCompile.h
+++ b/generic/tclCompile.h
@@ -9,7 +9,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclCompile.h,v 1.127 2010/09/27 19:42:38 msofer Exp $
+ * RCS: @(#) $Id: tclCompile.h,v 1.128 2010/10/20 20:52:28 ferrieux Exp $
  */
 
 #ifndef _TCLCOMPILATION
@@ -975,6 +975,14 @@ MODULE_SCOPE void	TclVerifyLocalLiteralTable(CompileEnv *envPtr);
 #endif
 MODULE_SCOPE int	TclWordKnownAtCompileTime(Tcl_Token *tokenPtr,
 			    Tcl_Obj *valuePtr);
+MODULE_SCOPE void	TclLogCommandInfo(Tcl_Interp *interp,
+					  const char *script,
+					  const char *command, int length,
+					  const unsigned char *pc, Tcl_Obj **tosPtr); 
+MODULE_SCOPE Tcl_Obj	*TclGetInnerContext(Tcl_Interp *interp,
+					    const unsigned char *pc, Tcl_Obj **tosPtr);
+MODULE_SCOPE Tcl_Obj	*TclNewInstNameObj(unsigned char inst);
+
 
 /*
  *----------------------------------------------------------------
diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index 5343ecd..a8b408e 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -14,7 +14,7 @@
  * 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 1.508 2010/10/20 13:34:11 dkf Exp $
+ * RCS: @(#) $Id: tclExecute.c,v 1.509 2010/10/20 20:52:28 ferrieux Exp $
  */
 
 #include "tclInt.h"
@@ -697,7 +697,8 @@ static void		FreeExprCodeInternalRep(Tcl_Obj *objPtr);
 static ExceptionRange *	GetExceptRangeForPc(const unsigned char *pc,
 			    int catchOnly, ByteCode *codePtr);
 static const char *	GetSrcInfoForPc(const unsigned char *pc,
-			    ByteCode *codePtr, int *lengthPtr);
+			    ByteCode *codePtr, int *lengthPtr,
+			    const unsigned char **pcBeg);
 static Tcl_Obj **	GrowEvaluationStack(ExecEnv *eePtr, int growth,
 			    int move);
 static void		IllegalExprOperandType(Tcl_Interp *interp,
@@ -2445,7 +2446,7 @@ TEBCresume(
 	    }
 
 	    codePtr->flags |= TCL_BYTECODE_RECOMPILE;
-	    bytes = GetSrcInfoForPc(pc, codePtr, &length);
+	    bytes = GetSrcInfoForPc(pc, codePtr, &length, NULL);
 	    opnd = TclGetUInt4AtPtr(pc+1);
 	    pc += (opnd-1);
 	    PUSH_OBJECT(Tcl_NewStringObj(bytes, length));
@@ -6264,9 +6265,11 @@ TEBCresume(
 	    goto abnormalReturn;
 	}
 	if ((result == TCL_ERROR) && !(iPtr->flags & ERR_ALREADY_LOGGED)) {
-	    bytes = GetSrcInfoForPc(pc, codePtr, &length);
+	    const unsigned char *pcBeg;
+
+	    bytes = GetSrcInfoForPc(pc, codePtr, &length, &pcBeg);
 	    DECACHE_STACK_INFO();
-	    Tcl_LogCommandInfo(interp, codePtr->source, bytes, bytes ? length : 0);
+	    TclLogCommandInfo(interp, codePtr->source, bytes, bytes ? length : 0, pcBeg, tosPtr);
 	    CACHE_STACK_INFO();
 	}
 	iPtr->flags &= ~ERR_ALREADY_LOGGED;
@@ -7899,7 +7902,7 @@ ValidatePcAndStackTop(
     if (checkStack &&
 	    ((stackTop < stackLowerBound) || (stackTop > stackUpperBound))) {
 	int numChars;
-	const char *cmd = GetSrcInfoForPc(pc, codePtr, &numChars);
+	const char *cmd = GetSrcInfoForPc(pc, codePtr, &numChars, NULL);
 
 	fprintf(stderr, "\nBad stack top %d at pc %u in TclNRExecuteByteCode (min %i, max %i)",
 		stackTop, relativePc, stackLowerBound, stackUpperBound);
@@ -8013,7 +8016,7 @@ TclGetSrcInfoForCmd(
     ByteCode *codePtr = (ByteCode *) cfPtr->data.tebc.codePtr;
 
     return GetSrcInfoForPc((unsigned char *) cfPtr->data.tebc.pc,
-	    codePtr, lenPtr);
+			   codePtr, lenPtr, NULL);
 }
 
 void
@@ -8025,7 +8028,7 @@ TclGetSrcInfoForPc(
     if (cfPtr->cmd.str.cmd == NULL) {
 	cfPtr->cmd.str.cmd = GetSrcInfoForPc(
 		(unsigned char *) cfPtr->data.tebc.pc, codePtr,
-		&cfPtr->cmd.str.len);
+		&cfPtr->cmd.str.len, NULL);
     }
 
     if (cfPtr->cmd.str.cmd != NULL) {
@@ -8076,15 +8079,18 @@ TclGetSrcInfoForPc(
 
 static const char *
 GetSrcInfoForPc(
-    const unsigned char *pc, /* The program counter value for which to
+    const unsigned char *pc,	/* The program counter value for which to
 				 * return the closest command's source info.
-				 * This points to a bytecode instruction in
+				 * This points within a bytecode instruction in
 				 * codePtr's code. */
     ByteCode *codePtr,		/* The bytecode sequence in which to look up
 				 * the command source for the pc. */
-    int *lengthPtr)		/* If non-NULL, the location where the length
+    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
+				 * where the current instruction starts.
+				 * If NULL; no pointer is stored. */
 {
     register int pcOffset = (pc - codePtr->codeStart);
     int numCmds = codePtr->numCommands;
@@ -8096,6 +8102,7 @@ GetSrcInfoForPc(
     int bestSrcLength = -1;	/* Initialized to avoid compiler warning. */
 
     if ((pcOffset < 0) || (pcOffset >= codePtr->numCodeBytes)) {
+	if (pcBeg != NULL) *pcBeg = NULL;
 	return NULL;
     }
 
@@ -8164,6 +8171,22 @@ GetSrcInfoForPc(
 	}
     }
 
+    if (pcBeg != NULL) {
+	const unsigned char *curr,*prev;
+
+	/* Walk from beginning of command or BC to pc, by complete
+	 * instructions. Stop when crossing pc; keep previous */
+
+	curr = prev = ((bestDist == INT_MAX) ?
+		       codePtr->codeStart :
+		       pc - bestDist);
+	while (curr <= pc) {
+	    prev = curr;
+	    curr += tclInstructionTable[*curr].numBytes;
+	}
+	*pcBeg = prev ; 
+    }
+
     if (bestDist == INT_MAX) {
 	return NULL;
     }
@@ -8171,6 +8194,7 @@ GetSrcInfoForPc(
     if (lengthPtr != NULL) {
 	*lengthPtr = bestSrcLength;
     }
+
     return (codePtr->source + bestSrcOffset);
 }
 
diff --git a/generic/tclInt.h b/generic/tclInt.h
index 1584e4a..c4ab6b3 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -15,7 +15,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclInt.h,v 1.484 2010/09/28 15:13:54 rmax Exp $
+ * RCS: @(#) $Id: tclInt.h,v 1.485 2010/10/20 20:52:28 ferrieux Exp $
  */
 
 #ifndef _TCLINT
@@ -2159,6 +2159,8 @@ typedef struct Interp {
     Tcl_Obj *errorStack;	/* [info errorstack] value (as a Tcl_Obj). */
     Tcl_Obj *upLiteral;		/* "UP" literal for [info errorstack] */
     Tcl_Obj *callLiteral;	/* "CALL" literal for [info errorstack] */
+    Tcl_Obj *innerLiteral;	/* "INNER" literal for [info errorstack] */
+    Tcl_Obj *innerContext;	/* cached list for fast reallocation */
     int resetErrorStack;        /* controls cleaning up of ::errorStack */
 
 #ifdef TCL_COMPILE_STATS
@@ -3099,6 +3101,8 @@ MODULE_SCOPE void	TclpThreadDeleteKey(void *keyPtr);
 MODULE_SCOPE void	TclpThreadSetMasterTSD(void *tsdKeyPtr, void *ptr);
 MODULE_SCOPE void *	TclpThreadGetMasterTSD(void *tsdKeyPtr);
 
+MODULE_SCOPE void	TclErrorStackResetIf(Tcl_Interp *interp, const char *msg, int length);
+
 /*
  *----------------------------------------------------------------
  * Command procedures in the generic core:
diff --git a/generic/tclNamesp.c b/generic/tclNamesp.c
index 2d1ce11..89e8a21 100644
--- a/generic/tclNamesp.c
+++ b/generic/tclNamesp.c
@@ -22,11 +22,11 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclNamesp.c,v 1.213 2010/10/01 12:52:49 dkf Exp $
+ * RCS: @(#) $Id: tclNamesp.c,v 1.214 2010/10/20 20:52:28 ferrieux Exp $
  */
 
 #include "tclInt.h"
-#include "tclCompile.h" /* just for NRCommand */
+#include "tclCompile.h" /* for NRCommand; and TclLogCommandInfo visibility */
 
 /*
  * Thread-local storage used to avoid having a global lock on data that is not
@@ -4851,31 +4851,36 @@ TclGetNamespaceChildTable(
 /*
  *----------------------------------------------------------------------
  *
- * Tcl_LogCommandInfo --
+ * TclLogCommandInfo --
  *
  *	This function is invoked after an error occurs in an interpreter. It
- *	adds information to iPtr->errorInfo field to describe the command that
- *	was being executed when the error occurred.
+ *	adds information to iPtr->errorInfo/errorStack fields to describe the
+ *	command that was being executed when the error occurred. When pc and
+ *	tosPtr are non-NULL, conveying a bytecode execution "inner context",
+ *	and the offending instruction is suitable, that inner context is
+ *	recorded in errorStack.
  *
  * Results:
  *	None.
  *
  * Side effects:
- *	Information about the command is added to errorInfo and the line
- *	number stored internally in the interpreter is set.
+ *	Information about the command is added to errorInfo/errorStack and the
+ *	line number stored internally in the interpreter is set.
  *
  *----------------------------------------------------------------------
  */
 
 void
-Tcl_LogCommandInfo(
+TclLogCommandInfo(
     Tcl_Interp *interp,		/* Interpreter in which to log information. */
     const char *script,		/* First character in script containing
 				 * command (must be <= command). */
     const char *command,	/* First character in command that generated
 				 * the error. */
-    int length)			/* Number of bytes in command (-1 means use
+    int length,			/* Number of bytes in command (-1 means use
 				 * all bytes up to first null byte). */
+    const unsigned char *pc,    /* current pc of bytecode execution context */
+    Tcl_Obj **tosPtr)           /* current stack of bytecode execution context */
 {
     register const char *p;
     Interp *iPtr = (Interp *) interp;
@@ -4962,6 +4967,18 @@ Tcl_LogCommandInfo(
 	Tcl_ListObjLength(interp, iPtr->errorStack, &len);
         /* reset while keeping the list intrep as much as possible */
         Tcl_ListObjReplace(interp, iPtr->errorStack, 0, len, 0, NULL);
+        if (pc != NULL) {
+            Tcl_Obj *innerContext;
+
+            innerContext = TclGetInnerContext(interp, pc, tosPtr);
+            if (innerContext != NULL) {
+                Tcl_ListObjAppendElement(NULL, iPtr->errorStack, iPtr->innerLiteral);
+                Tcl_ListObjAppendElement(NULL, iPtr->errorStack, innerContext);
+            }
+        } else if (command != NULL) {
+            Tcl_ListObjAppendElement(NULL, iPtr->errorStack, iPtr->innerLiteral);
+            Tcl_ListObjAppendElement(NULL, iPtr->errorStack, Tcl_NewStringObj(command, length));
+        }
     } 
 
     if (!iPtr->framePtr->objc) {
@@ -4981,6 +4998,80 @@ Tcl_LogCommandInfo(
 }
 
 /*
+ *----------------------------------------------------------------------
+ *
+ * TclErrorStackResetIf --
+ *
+ *      The TIP 348 reset/no-bc part of TLCI, for specific use by
+ *      TclCompileSyntaxError.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Reset errorstack if it needs be, and in that case remember the
+ *	passed-in error message as inner context.
+ *
+ *----------------------------------------------------------------------
+ */
+void TclErrorStackResetIf(Tcl_Interp *interp, const char *msg, int length)
+{
+    Interp *iPtr = (Interp *) interp;
+
+    if (Tcl_IsShared(iPtr->errorStack)) {
+        Tcl_Obj *newObj;
+            
+        newObj = Tcl_DuplicateObj(iPtr->errorStack);
+        Tcl_DecrRefCount(iPtr->errorStack);
+        Tcl_IncrRefCount(newObj);
+        iPtr->errorStack = newObj;
+    }
+    if (iPtr->resetErrorStack) {
+	int len;
+
+        iPtr->resetErrorStack = 0;
+	Tcl_ListObjLength(interp, iPtr->errorStack, &len);
+        /* reset while keeping the list intrep as much as possible */
+        Tcl_ListObjReplace(interp, iPtr->errorStack, 0, len, 0, NULL);
+        Tcl_ListObjAppendElement(NULL, iPtr->errorStack, iPtr->innerLiteral);
+        Tcl_ListObjAppendElement(NULL, iPtr->errorStack, Tcl_NewStringObj(msg, length));
+    } 
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_LogCommandInfo --
+ *
+ *	This function is invoked after an error occurs in an interpreter. It
+ *	adds information to iPtr->errorInfo/errorStack fields to describe the
+ *	command that was being executed when the error occurred.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Information about the command is added to errorInfo/errorStack and the
+ *	line number stored internally in the interpreter is set.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_LogCommandInfo(
+    Tcl_Interp *interp,		/* Interpreter in which to log information. */
+    const char *script,		/* First character in script containing
+				 * command (must be <= command). */
+    const char *command,	/* First character in command that generated
+				 * the error. */
+    int length)			/* Number of bytes in command (-1 means use
+				 * all bytes up to first null byte). */
+{
+    TclLogCommandInfo(interp, script, command, length, NULL, NULL);
+}
+
+
+/*
  * Local Variables:
  * mode: c
  * c-basic-offset: 4