Fix [d4e7780ca1681cd095dbd81fe264feff75c988f7|d4e7780ca1]: "global" cmd literal sharing vs. per-interp resolvers

15 files changed, 152 insertions, 91 deletions

diff --git a/generic/tclAssembly.c b/generic/tclAssembly.c
index 7a5ffcc..06f277f 100644
--- a/generic/tclAssembly.c
+++ b/generic/tclAssembly.c
@@ -1300,7 +1300,7 @@ AssembleOneLine(
 	    goto cleanup;
 	}
 	operand1 = TclGetStringFromObj(operand1Obj, &operand1Len);
-	litIndex = TclRegisterNewLiteral(envPtr, operand1, operand1Len);
+	litIndex = TclRegisterLiteral(envPtr, operand1, operand1Len, 0);
 	BBEmitInst1or4(assemEnvPtr, tblIdx, litIndex, 0);
 	break;
 
@@ -1449,7 +1449,7 @@ AssembleOneLine(
 	    goto cleanup;
 	} else {
 	    operand1 = TclGetStringFromObj(operand1Obj, &operand1Len);
-	    litIndex = TclRegisterNewLiteral(envPtr, operand1, operand1Len);
+	    litIndex = TclRegisterLiteral(envPtr, operand1, operand1Len, 0);
 
 	    /*
 	     * Assumes that PUSH is the first slot!
@@ -3541,7 +3541,7 @@ StackCheckExit(
 	     * Emit a 'push' of the empty literal.
 	     */
 
-	    litIndex = TclRegisterNewLiteral(envPtr, "", 0);
+	    litIndex = TclRegisterLiteral(envPtr, "", 0, 0);
 
 	    /*
 	     * Assumes that 'push' is at slot 0 in TalInstructionTable.
diff --git a/generic/tclCompCmdsGR.c b/generic/tclCompCmdsGR.c
index 593a8af..ff5495c 100644
--- a/generic/tclCompCmdsGR.c
+++ b/generic/tclCompCmdsGR.c
@@ -2761,7 +2761,7 @@ TclCompileSyntaxError(
     const char *bytes = TclGetStringFromObj(msg, &numBytes);
 
     TclErrorStackResetIf(interp, bytes, numBytes);
-    TclEmitPush(TclRegisterNewLiteral(envPtr, bytes, numBytes), envPtr);
+    TclEmitPush(TclRegisterLiteral(envPtr, bytes, numBytes, 0), envPtr);
     CompileReturnInternal(envPtr, INST_SYNTAX, TCL_ERROR, 0,
 	    TclNoErrorStack(interp, Tcl_GetReturnOptions(interp, TCL_ERROR)));
     Tcl_ResetResult(interp);
diff --git a/generic/tclCompCmdsSZ.c b/generic/tclCompCmdsSZ.c
index 2503089..10b3cc8 100644
--- a/generic/tclCompCmdsSZ.c
+++ b/generic/tclCompCmdsSZ.c
@@ -1456,8 +1456,8 @@ TclSubstCompile(
 
 	switch (tokenPtr->type) {
 	case TCL_TOKEN_TEXT:
-	    literal = TclRegisterNewLiteral(envPtr,
-		    tokenPtr->start, tokenPtr->size);
+	    literal = TclRegisterLiteral(envPtr,
+		    tokenPtr->start, tokenPtr->size, 0);
 	    TclEmitPush(literal, envPtr);
 	    TclAdvanceLines(&bline, tokenPtr->start,
 		    tokenPtr->start + tokenPtr->size);
@@ -1466,7 +1466,7 @@ TclSubstCompile(
 	case TCL_TOKEN_BS:
 	    length = TclParseBackslash(tokenPtr->start, tokenPtr->size,
 		    NULL, buf);
-	    literal = TclRegisterNewLiteral(envPtr, buf, length);
+	    literal = TclRegisterLiteral(envPtr, buf, length, 0);
 	    TclEmitPush(literal, envPtr);
 	    count++;
 	    continue;
diff --git a/generic/tclCompExpr.c b/generic/tclCompExpr.c
index 654666a..83bb883 100644
--- a/generic/tclCompExpr.c
+++ b/generic/tclCompExpr.c
@@ -2267,9 +2267,9 @@ CompileExprTree(
 		p = TclGetStringFromObj(*funcObjv, &length);
 		funcObjv++;
 		Tcl_DStringAppend(&cmdName, p, length);
-		TclEmitPush(TclRegisterNewCmdLiteral(envPtr,
+		TclEmitPush(TclRegisterLiteral(envPtr,
 			Tcl_DStringValue(&cmdName),
-			Tcl_DStringLength(&cmdName)), envPtr);
+			Tcl_DStringLength(&cmdName), LITERAL_CMD_NAME), envPtr);
 		Tcl_DStringFree(&cmdName);
 
 		/*
@@ -2376,8 +2376,8 @@ CompileExprTree(
 		pc1 = CurrentOffset(envPtr);
 		TclEmitInstInt1((nodePtr->lexeme == AND) ? INST_JUMP_FALSE1
 			: INST_JUMP_TRUE1, 0, envPtr);
-		TclEmitPush(TclRegisterNewLiteral(envPtr,
-			(nodePtr->lexeme == AND) ? "1" : "0", 1), envPtr);
+		TclEmitPush(TclRegisterLiteral(envPtr,
+			(nodePtr->lexeme == AND) ? "1" : "0", 1, 0), envPtr);
 		pc2 = CurrentOffset(envPtr);
 		TclEmitInstInt1(INST_JUMP1, 0, envPtr);
 		TclAdjustStackDepth(-1, envPtr);
@@ -2386,8 +2386,8 @@ CompileExprTree(
 		if (TclFixupForwardJumpToHere(envPtr, &jumpPtr->jump, 127)) {
 		    pc2 += 3;
 		}
-		TclEmitPush(TclRegisterNewLiteral(envPtr,
-			(nodePtr->lexeme == AND) ? "0" : "1", 1), envPtr);
+		TclEmitPush(TclRegisterLiteral(envPtr,
+			(nodePtr->lexeme == AND) ? "0" : "1", 1, 0), envPtr);
 		TclStoreInt1AtPtr(CurrentOffset(envPtr) - pc2,
 			envPtr->codeStart + pc2 + 1);
 		convert = 0;
@@ -2421,7 +2421,7 @@ CompileExprTree(
 	    if (optimize) {
 		int length;
 		const char *bytes = TclGetStringFromObj(literal, &length);
-		int index = TclRegisterNewLiteral(envPtr, bytes, length);
+		int index = TclRegisterLiteral(envPtr, bytes, length, 0);
 		Tcl_Obj *objPtr = TclFetchLiteral(envPtr, index);
 
 		if ((objPtr->typePtr == NULL) && (literal->typePtr != NULL)) {
@@ -2479,8 +2479,8 @@ CompileExprTree(
 		    if (objPtr->bytes) {
 			Tcl_Obj *tableValue;
 
-			index = TclRegisterNewLiteral(envPtr, objPtr->bytes,
-				objPtr->length);
+			index = TclRegisterLiteral(envPtr, objPtr->bytes,
+				objPtr->length, 0);
 			tableValue = TclFetchLiteral(envPtr, index);
 			if ((tableValue->typePtr == NULL) &&
 				(objPtr->typePtr != NULL)) {
diff --git a/generic/tclCompile.c b/generic/tclCompile.c
index 0024f1e..c588731 100644
--- a/generic/tclCompile.c
+++ b/generic/tclCompile.c
@@ -1792,9 +1792,17 @@ CompileCmdLiteral(
     CompileEnv *envPtr)
 {
     int numBytes;
-    const char *bytes = TclGetStringFromObj(cmdObj, &numBytes);
-    int cmdLitIdx = TclRegisterNewCmdLiteral(envPtr, bytes, numBytes);
-    Command *cmdPtr = (Command *) Tcl_GetCommandFromObj(interp, cmdObj);
+    const char *bytes;
+    Command *cmdPtr;
+    int cmdLitIdx, extraLiteralFlags = LITERAL_CMD_NAME;
+
+    cmdPtr = (Command *) Tcl_GetCommandFromObj(interp, cmdObj);
+    if ((cmdPtr != NULL) && (cmdPtr->flags & CMD_VIA_RESOLVER)) {
+	extraLiteralFlags |= LITERAL_UNSHARED;
+    }
+
+    bytes = Tcl_GetStringFromObj(cmdObj, &numBytes);
+    cmdLitIdx = TclRegisterLiteral(envPtr, bytes, numBytes, extraLiteralFlags);
 
     if (cmdPtr) {
 	TclSetCmdNameObj(interp, TclFetchLiteral(envPtr, cmdLitIdx), cmdPtr);
@@ -1829,8 +1837,8 @@ TclCompileInvocation(
 	    continue;
 	}
 
-	objIdx = TclRegisterNewLiteral(envPtr,
-		tokenPtr[1].start, tokenPtr[1].size);
+	objIdx = TclRegisterLiteral(envPtr,
+		tokenPtr[1].start, tokenPtr[1].size, 0);
 	if (envPtr->clNext) {
 	    TclContinuationsEnterDerived(TclFetchLiteral(envPtr, objIdx),
 		    tokenPtr[1].start - envPtr->source, envPtr->clNext);
@@ -1879,8 +1887,8 @@ CompileExpanded(
 	    continue;
 	}
 
-	objIdx = TclRegisterNewLiteral(envPtr,
-		tokenPtr[1].start, tokenPtr[1].size);
+	objIdx = TclRegisterLiteral(envPtr,
+		tokenPtr[1].start, tokenPtr[1].size, 0);
 	if (envPtr->clNext) {
 	    TclContinuationsEnterDerived(TclFetchLiteral(envPtr, objIdx),
 		    tokenPtr[1].start - envPtr->source, envPtr->clNext);
diff --git a/generic/tclCompile.h b/generic/tclCompile.h
index f99c07c..89cdc59 100644
--- a/generic/tclCompile.h
+++ b/generic/tclCompile.h
@@ -1095,7 +1095,7 @@ MODULE_SCOPE int	TclCreateAuxData(ClientData clientData,
 MODULE_SCOPE int	TclCreateExceptRange(ExceptionRangeType type,
 			    CompileEnv *envPtr);
 MODULE_SCOPE ExecEnv *	TclCreateExecEnv(Tcl_Interp *interp, int size);
-MODULE_SCOPE Tcl_Obj *	TclCreateLiteral(Interp *iPtr, char *bytes,
+MODULE_SCOPE Tcl_Obj *	TclCreateLiteral(Interp *iPtr, const char *bytes,
 			    int length, unsigned int hash, int *newPtr,
 			    Namespace *nsPtr, int flags,
 			    LiteralEntry **globalPtrPtr);
@@ -1210,29 +1210,7 @@ MODULE_SCOPE int	TclPushProcCallFrame(ClientData clientData,
 
 #define LITERAL_ON_HEAP		0x01
 #define LITERAL_CMD_NAME	0x02
-
-/*
- * Form of TclRegisterLiteral with flags == 0. In that case, it is safe to
- * cast away constness, and it is cleanest to do that here, all in one place.
- *
- * int TclRegisterNewLiteral(CompileEnv *envPtr, const char *bytes,
- *			     int length);
- */
-
-#define TclRegisterNewLiteral(envPtr, bytes, length) \
-    TclRegisterLiteral(envPtr, (char *)(bytes), length, /*flags*/ 0)
-
-/*
- * Form of TclRegisterLiteral with flags == LITERAL_CMD_NAME. In that case, it
- * is safe to cast away constness, and it is cleanest to do that here, all in
- * one place.
- *
- * int TclRegisterNewNSLiteral(CompileEnv *envPtr, const char *bytes,
- *			       int length);
- */
-
-#define TclRegisterNewCmdLiteral(envPtr, bytes, length) \
-    TclRegisterLiteral(envPtr, (char *)(bytes), length, LITERAL_CMD_NAME)
+#define LITERAL_UNSHARED	0x04
 
 /*
  * Macro used to manually adjust the stack requirements; used in cases where
@@ -1549,9 +1527,9 @@ MODULE_SCOPE int	TclPushProcCallFrame(ClientData clientData,
  */
 
 #define PushLiteral(envPtr, string, length) \
-    TclEmitPush(TclRegisterNewLiteral((envPtr), (string), (length)), (envPtr))
+    TclEmitPush(TclRegisterLiteral(envPtr, string, length, 0), (envPtr))
 #define PushStringLiteral(envPtr, string) \
-    PushLiteral((envPtr), (string), (int) (sizeof(string "") - 1))
+    PushLiteral(envPtr, string, (int) (sizeof(string "") - 1))
 
 /*
  * Macro to advance to the next token; it is more mnemonic than the address
diff --git a/generic/tclEnsemble.c b/generic/tclEnsemble.c
index 2766769..43813f1 100644
--- a/generic/tclEnsemble.c
+++ b/generic/tclEnsemble.c
@@ -3306,7 +3306,7 @@ CompileToInvokedCommand(
     Tcl_Token *tokPtr;
     Tcl_Obj *objPtr, **words;
     char *bytes;
-    int length, i, numWords, cmdLit;
+    int length, i, numWords, cmdLit, extraLiteralFlags = LITERAL_CMD_NAME;
     DefineLineInformation;
 
     /*
@@ -3326,8 +3326,8 @@ CompileToInvokedCommand(
 
 	SetLineInformation(i);
 	if (tokPtr->type == TCL_TOKEN_SIMPLE_WORD) {
-	    int literal = TclRegisterNewLiteral(envPtr,
-		    tokPtr[1].start, tokPtr[1].size);
+	    int literal = TclRegisterLiteral(envPtr,
+		    tokPtr[1].start, tokPtr[1].size, 0);
 
 	    if (envPtr->clNext) {
 		TclContinuationsEnterDerived(
@@ -3348,8 +3348,11 @@ CompileToInvokedCommand(
 
     objPtr = Tcl_NewObj();
     Tcl_GetCommandFullName(interp, (Tcl_Command) cmdPtr, objPtr);
-    bytes = TclGetStringFromObj(objPtr, &length);
-    cmdLit = TclRegisterNewCmdLiteral(envPtr, bytes, length);
+    bytes = Tcl_GetStringFromObj(objPtr, &length);
+    if ((cmdPtr != NULL) && (cmdPtr->flags & CMD_VIA_RESOLVER)) {
+	extraLiteralFlags |= LITERAL_UNSHARED;
+    }
+    cmdLit = TclRegisterLiteral(envPtr, bytes, length, extraLiteralFlags);
     TclSetCmdNameObj(interp, TclFetchLiteral(envPtr, cmdLit), cmdPtr);
     TclEmitPush(cmdLit, envPtr);
     TclDecrRefCount(objPtr);
diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index 704e494..df36958 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -1554,7 +1554,7 @@ CompileExprObj(
 	 */
 
 	if (compEnv.codeNext == compEnv.codeStart) {
-	    TclEmitPush(TclRegisterNewLiteral(&compEnv, "0", 1),
+	    TclEmitPush(TclRegisterLiteral(&compEnv, "0", 1, 0),
 		    &compEnv);
 	}
 
diff --git a/generic/tclInt.decls b/generic/tclInt.decls
index 4e7e422..c00dff1 100644
--- a/generic/tclInt.decls
+++ b/generic/tclInt.decls
@@ -1009,7 +1009,7 @@ declare 250 {
 # Allow extensions for optimization
 declare 251 {
     int TclRegisterLiteral(void *envPtr,
-	    char *bytes, int length, int flags)
+	    const char *bytes, int length, int flags)
 }
 
 ##############################################################################
diff --git a/generic/tclInt.h b/generic/tclInt.h
index b39c8ea..da1b5c5 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -1690,11 +1690,13 @@ typedef struct Command {
  * (these last two flags are defined in tcl.h)
  */
 
-#define CMD_IS_DELETED		    0x1
-#define CMD_TRACE_ACTIVE	    0x2
-#define CMD_HAS_EXEC_TRACES	    0x4
-#define CMD_COMPILES_EXPANDED	    0x8
+#define CMD_IS_DELETED		    0x01
+#define CMD_TRACE_ACTIVE	    0x02
+#define CMD_HAS_EXEC_TRACES	    0x04
+#define CMD_COMPILES_EXPANDED	    0x08
 #define CMD_REDEF_IN_PROGRESS	    0x10
+#define CMD_VIA_RESOLVER	    0x20
+
 
 /*
  *----------------------------------------------------------------
diff --git a/generic/tclIntDecls.h b/generic/tclIntDecls.h
index f95f999..dfa5727 100644
--- a/generic/tclIntDecls.h
+++ b/generic/tclIntDecls.h
@@ -615,7 +615,7 @@ EXTERN char *		TclDoubleDigits(double dv, int ndigits, int flags,
 EXTERN void		TclSetSlaveCancelFlags(Tcl_Interp *interp, int flags,
 				int force);
 /* 251 */
-EXTERN int		TclRegisterLiteral(void *envPtr, char *bytes,
+EXTERN int		TclRegisterLiteral(void *envPtr, const char *bytes,
 				int length, int flags);
 
 typedef struct TclIntStubs {
@@ -873,7 +873,7 @@ typedef struct TclIntStubs {
     int (*tclCopyChannel) (Tcl_Interp *interp, Tcl_Channel inChan, Tcl_Channel outChan, Tcl_WideInt toRead, Tcl_Obj *cmdPtr); /* 248 */
     char * (*tclDoubleDigits) (double dv, int ndigits, int flags, int *decpt, int *signum, char **endPtr); /* 249 */
     void (*tclSetSlaveCancelFlags) (Tcl_Interp *interp, int flags, int force); /* 250 */
-    int (*tclRegisterLiteral) (void *envPtr, char *bytes, int length, int flags); /* 251 */
+    int (*tclRegisterLiteral) (void *envPtr, const char *bytes, int length, int flags); /* 251 */
 } TclIntStubs;
 
 extern const TclIntStubs *tclIntStubsPtr;
diff --git a/generic/tclLiteral.c b/generic/tclLiteral.c
index 9f01144..9922cec 100644
--- a/generic/tclLiteral.c
+++ b/generic/tclLiteral.c
@@ -174,7 +174,7 @@ TclDeleteLiteralTable(
 Tcl_Obj *
 TclCreateLiteral(
     Interp *iPtr,
-    char *bytes,		/* The start of the string. Note that this is
+    const char *bytes,	/* The start of the string. Note that this is
 				 * not a NUL-terminated string. */
     int length,			/* Number of bytes in the string. */
     unsigned hash,		/* The string's hash. If -1, it will be
@@ -214,7 +214,7 @@ TclCreateLiteral(
 	    if (globalPtrPtr) {
 		*globalPtrPtr = globalPtr;
 	    }
-	    if (flags & LITERAL_ON_HEAP) {
+	    if ((flags & LITERAL_ON_HEAP)) {
 		ckfree(bytes);
 	    }
 	    globalPtr->refCount++;
@@ -222,7 +222,7 @@ TclCreateLiteral(
 	}
     }
     if (!newPtr) {
-	if (flags & LITERAL_ON_HEAP) {
+	if ((flags & LITERAL_ON_HEAP)) {
 	    ckfree(bytes);
 	}
 	return NULL;
@@ -235,13 +235,23 @@ TclCreateLiteral(
 
     TclNewObj(objPtr);
     Tcl_IncrRefCount(objPtr);
-    if (flags & LITERAL_ON_HEAP) {
-	objPtr->bytes = bytes;
+    if ((flags & LITERAL_ON_HEAP)) {
+	objPtr->bytes = (char *) bytes;
 	objPtr->length = length;
     } else {
 	TclInitStringRep(objPtr, bytes, length);
     }
 
+    if ((flags & LITERAL_UNSHARED)) {
+	/*
+	 * Make clear, that no global value is returned
+	 */
+	if (globalPtrPtr != NULL) {
+	    *globalPtrPtr = NULL;
+	}
+	return objPtr;
+    }
+
 #ifdef TCL_COMPILE_DEBUG
     if (LookupLiteralEntry((Tcl_Interp *) iPtr, objPtr) != NULL) {
 	Tcl_Panic("%s: literal \"%.*s\" found globally but shouldn't be",
@@ -360,7 +370,7 @@ int
 TclRegisterLiteral(
     void *ePtr,		/* Points to the CompileEnv in whose object
 				 * array an object is found or created. */
-    register char *bytes,	/* Points to string for which to find or
+    register const char *bytes,	/* Points to string for which to find or
 				 * create an object in CompileEnv's object
 				 * array. */
     int length,			/* Number of bytes in the string. If < 0, the
@@ -398,7 +408,7 @@ TclRegisterLiteral(
 	if ((objPtr->length == length) && ((length == 0)
 		|| ((objPtr->bytes[0] == bytes[0])
 		&& (memcmp(objPtr->bytes, bytes, (unsigned) length) == 0)))) {
-	    if (flags & LITERAL_ON_HEAP) {
+	    if ((flags & LITERAL_ON_HEAP)) {
 		ckfree(bytes);
 	    }
 	    objIndex = (localPtr - envPtr->literalArrayPtr);
@@ -417,7 +427,7 @@ TclRegisterLiteral(
      * the namespace as the interp's global NS.
      */
 
-    if (flags & LITERAL_CMD_NAME) {
+    if ((flags & LITERAL_CMD_NAME)) {
 	if ((length >= 2) && (bytes[0] == ':') && (bytes[1] == ':')) {
 	    nsPtr = iPtr->globalNsPtr;
 	} else {
@@ -1026,7 +1036,7 @@ TclInvalidateCmdLiteral(
 				 * invalidate a cmd literal. */
 {
     Interp *iPtr = (Interp *) interp;
-    Tcl_Obj *literalObjPtr = TclCreateLiteral(iPtr, (char *) name,
+    Tcl_Obj *literalObjPtr = TclCreateLiteral(iPtr, name,
 	    strlen(name), -1, NULL, nsPtr, 0, NULL);
 
     if (literalObjPtr != NULL) {
@@ -1153,13 +1163,6 @@ TclVerifyLocalLiteralTable(
 			"TclVerifyLocalLiteralTable",
 			(length>60? 60 : length), bytes, localPtr->refCount);
 	    }
-	    if (LookupLiteralEntry((Tcl_Interp *) envPtr->iPtr,
-		    localPtr->objPtr) == NULL) {
-		bytes = TclGetStringFromObj(localPtr->objPtr, &length);
-		Tcl_Panic("%s: local literal \"%.*s\" is not global",
-			"TclVerifyLocalLiteralTable",
-			(length>60? 60 : length), bytes);
-	    }
 	    if (localPtr->objPtr->bytes == NULL) {
 		Tcl_Panic("%s: literal has NULL string rep",
 			"TclVerifyLocalLiteralTable");
diff --git a/generic/tclNamesp.c b/generic/tclNamesp.c
index 1fef919..7f6ecf5 100644
--- a/generic/tclNamesp.c
+++ b/generic/tclNamesp.c
@@ -2566,7 +2566,9 @@ Tcl_FindCommand(
 	}
 
 	if (result == TCL_OK) {
+	    ((Command *)cmd)->flags |= CMD_VIA_RESOLVER;
 	    return cmd;
+
 	} else if (result != TCL_CONTINUE) {
 	    return NULL;
 	}
@@ -2658,6 +2660,7 @@ Tcl_FindCommand(
     }
 
     if (cmdPtr != NULL) {
+	cmdPtr->flags  &= ~CMD_VIA_RESOLVER;
 	return (Tcl_Command) cmdPtr;
     }
 
diff --git a/generic/tclObj.c b/generic/tclObj.c
index df17f13..d3f59ec 100644
--- a/generic/tclObj.c
+++ b/generic/tclObj.c
@@ -4264,8 +4264,13 @@ TclSetCmdNameObj(
     Command *cmdPtr)		/* Points to Command structure that the
 				 * CmdName object should refer to. */
 {
+    register ResolvedCmdName *resPtr;
+
     if (objPtr->typePtr == &tclCmdNameType) {
-	return;
+	resPtr = objPtr->internalRep.twoPtrValue.ptr1;
+	if (resPtr != NULL && resPtr->cmdPtr == cmdPtr) {
+	    return;
+	}
     }
 
     SetCmdNameObj(interp, objPtr, cmdPtr, NULL);
diff --git a/generic/tclTest.c b/generic/tclTest.c
index e0ed374..47d85e1 100644
--- a/generic/tclTest.c
+++ b/generic/tclTest.c
@@ -7326,24 +7326,83 @@ InterpCmdResolver(
     CallFrame *varFramePtr = iPtr->varFramePtr;
     Proc *procPtr = (varFramePtr->isProcCallFrame & FRAME_IS_PROC) ?
             varFramePtr->procPtr : NULL;
-    Namespace *ns2NsPtr = (Namespace *)
-            Tcl_FindNamespace(interp, "::ns2", NULL, 0);
+    Namespace *callerNsPtr = varFramePtr->nsPtr;
+    Tcl_Command resolvedCmdPtr = NULL;
 
-    if (procPtr && (procPtr->cmdPtr->nsPtr == iPtr->globalNsPtr
-            || (ns2NsPtr && procPtr->cmdPtr->nsPtr == ns2NsPtr))) {
-        const char *callingCmdName =
+    /*
+     * Just do something special on a cmd literal "z" in two cases:
+     *  A)  when the caller is a proc "x", and the proc is either in "::" or in "::ns2".
+     *  B) the caller's namespace is "ctx1" or "ctx2"
+     */
+    if ( (name[0] == 'z') && (name[1] == '\0') ) {
+        Namespace *ns2NsPtr = (Namespace *) Tcl_FindNamespace(interp, "::ns2", NULL, 0);
+
+        if (procPtr != NULL
+            && ((procPtr->cmdPtr->nsPtr == iPtr->globalNsPtr)
+                || (ns2NsPtr != NULL && procPtr->cmdPtr->nsPtr == ns2NsPtr)
+                )
+            ) {
+            /*
+             * Case A)
+             *
+             *    - The context, in which this resolver becomes active, is
+             *      determined by the name of the caller proc, which has to be
+             *      named "x".
+             *
+             *    - To determine the name of the caller proc, the proc is taken
+             *      from the topmost stack frame.
+             *
+             *    - Note that the context is NOT provided during byte-code
+             *      compilation (e.g. in TclProcCompileProc)
+             *
+             *   When these conditions hold, this function resolves the
+             *   passed-in cmd literal into a cmd "y", which is taken from the
+             *   the global namespace (for simplicity).
+             */
+
+            const char *callingCmdName =
                 Tcl_GetCommandName(interp, (Tcl_Command) procPtr->cmdPtr);
 
-        if ((callingCmdName[0] == 'x') && (callingCmdName[1] == '\0')
-                && (name[0] == 'z') && (name[1] == '\0')) {
-            Tcl_Command sourceCmdPtr = Tcl_FindCommand(interp, "y", NULL,
-                    TCL_GLOBAL_ONLY);
+            if ( callingCmdName[0] == 'x' && callingCmdName[1] == '\0' ) {
+                resolvedCmdPtr = Tcl_FindCommand(interp, "y", NULL, TCL_GLOBAL_ONLY);
+            }
+        } else if (callerNsPtr != NULL) {
+            /*
+             * Case B)
+             *
+             *    - The context, in which this resolver becomes active, is
+             *      determined by the name of the parent namespace, which has
+             *      to be named "ctx1" or "ctx2".
+             *
+             *    - To determine the name of the parent namesace, it is taken
+             *      from the 2nd highest stack frame.
+             *
+             *    - Note that the context can be provided during byte-code
+             *      compilation (e.g. in TclProcCompileProc)
+             *
+             *   When these conditions hold, this function resolves the
+             *   passed-in cmd literal into a cmd "y" or "Y" depending on the
+             *   context. The resolved procs are taken from the the global
+             *   namespace (for simplicity).
+             */
+
+            CallFrame *parentFramePtr = varFramePtr->callerPtr;
+            char *context = parentFramePtr != NULL ? parentFramePtr->nsPtr->name : "(NULL)";
 
-            if (sourceCmdPtr != NULL) {
-                *rPtr = sourceCmdPtr;
-                return TCL_OK;
+            if (strcmp(context, "ctx1") == 0 && (name[0] == 'z') && (name[1] == '\0')) {
+                resolvedCmdPtr = Tcl_FindCommand(interp, "y", NULL, TCL_GLOBAL_ONLY);
+                /* fprintf(stderr, "... y ==> %p\n", resolvedCmdPtr);*/
+
+            } else if (strcmp(context, "ctx2") == 0 && (name[0] == 'z') && (name[1] == '\0')) {
+                resolvedCmdPtr = Tcl_FindCommand(interp, "Y", NULL, TCL_GLOBAL_ONLY);
+                /*fprintf(stderr, "... Y ==> %p\n", resolvedCmdPtr);*/
             }
         }
+
+        if (resolvedCmdPtr != NULL) {
+            *rPtr = resolvedCmdPtr;
+            return TCL_OK;
+        }
     }
     return TCL_CONTINUE;
 }