Many simplifications to the TIP 280 machinery.

   * Removed support for non-NULL invoker when TCL_EVAL_DIRECT requested.
   * Eliminated TCL_EVAL_CTX eval flag.
   * Removed Tcl_Preserve-ability of ContLineLoc pointers.
   * Removed clLoc field of CompileEnv struct.

8 files changed, 39 insertions, 170 deletions

diff --git a/generic/tclBasic.c b/generic/tclBasic.c
index baa2f2c..7110025 100644
--- a/generic/tclBasic.c
+++ b/generic/tclBasic.c
@@ -5011,12 +5011,11 @@ TclEvalEx(
     /*
      * TIP #280 Initialize tracking. Do not push on the frame stack yet.
      *
-     * We may continue counting based on a specific context (CTX), or open a
-     * new context, either for a sourced script, or 'eval'. For sourced files
-     * we always have a path object, even if nothing was specified in the
-     * interp itself. That makes code using it simpler as NULL checks can be
-     * left out. Sourced file without path in the 'scriptFile' is possible
-     * during Tcl initialization.
+     * We open a new context, either for a sourced script, or 'eval'.
+     * For sourced files we always have a path object, even if nothing was
+     * specified in the interp itself. That makes code using it simpler as
+     * NULL checks can be left out. Sourced file without path in the
+     * 'scriptFile' is possible during Tcl initialization.
      */
 
     eeFramePtr->level = iPtr->cmdFramePtr ? iPtr->cmdFramePtr->level + 1 : 1;
@@ -5027,15 +5026,7 @@ TclEvalEx(
     eeFramePtr->line = NULL;
 
     iPtr->cmdFramePtr = eeFramePtr;
-    if (iPtr->evalFlags & TCL_EVAL_CTX) {
-	/*
-	 * Path information comes out of the context.
-	 */
-
-	eeFramePtr->type = TCL_LOCATION_SOURCE;
-	eeFramePtr->data.eval.path = iPtr->invokeCmdFramePtr->data.eval.path;
-	Tcl_IncrRefCount(eeFramePtr->data.eval.path);
-    } else if (iPtr->evalFlags & TCL_EVAL_FILE) {
+    if (iPtr->evalFlags & TCL_EVAL_FILE) {
 	/*
 	 * Set up for a sourced file.
 	 */
@@ -5902,6 +5893,11 @@ Tcl_GlobalEvalObj(
  *	compiled into bytecodes if necessary, unless TCL_EVAL_DIRECT is
  *	specified.
  *
+ *	If the flag TCL_EVAL_DIRECT is passed in, the value of invoker
+ *	must be NULL.  Support for non-NULL invokers in that mode has
+ *	been removed since it was unused and untested.  Failure to 
+ *	follow this limitation will lead to an assertion panic.
+ *
  * Results:
  *	The return value is one of the return codes defined in tcl.h (such as
  *	TCL_OK), and the interpreter's result contains a value to supplement
@@ -6076,14 +6072,6 @@ TclNREvalObjEx(
 	 * We're not supposed to use the compiler or byte-code
 	 * interpreter. Let Tcl_EvalEx evaluate the command directly (and
 	 * probably more slowly).
-	 *
-	 * TIP #280. Propagate context as much as we can. Especially if the
-	 * script to evaluate is a single literal it makes sense to look if
-	 * our context is one with absolute line numbers we can then track
-	 * into the literal itself too.
-	 *
-	 * See also tclCompile.c, TclInitCompileEnv, for the equivalent code
-	 * in the bytecode compiler.
 	 */
 
 	const char *script;
@@ -6107,92 +6095,19 @@ TclNREvalObjEx(
 	 */
 
 	ContLineLoc *saveCLLocPtr = iPtr->scriptCLLocPtr;
-	ContLineLoc *clLocPtr = TclContinuationsGet(objPtr);
-
-	if (clLocPtr) {
-	    iPtr->scriptCLLocPtr = clLocPtr;
-	    Tcl_Preserve(iPtr->scriptCLLocPtr);
-	} else {
-	    iPtr->scriptCLLocPtr = NULL;
-	}
-
-	Tcl_IncrRefCount(objPtr);
-	if (invoker == NULL) {
-	    /*
-	     * No context, force opening of our own.
-	     */
-
-	    script = Tcl_GetStringFromObj(objPtr, &numSrcBytes);
-	    result = Tcl_EvalEx(interp, script, numSrcBytes, flags);
-	} else {
-	    /*
-	     * We have an invoker, describing the command asking for the
-	     * evaluation of a subordinate script. This script may originate
-	     * in a literal word, or from a variable, etc. Using the line
-	     * array we now check if we have good line information for the
-	     * relevant word. The type of context is relevant as well. In a
-	     * non-'source' context we don't have to try tracking lines.
-	     *
-	     * First see if the word exists and is a literal. If not we go
-	     * through the easy dynamic branch. No need to perform more
-	     * complex invokations.
-	     */
-
-	    int pc = 0;
-	    CmdFrame *ctxPtr = TclStackAlloc(interp, sizeof(CmdFrame));
-
-	    *ctxPtr = *invoker;
-	    if (invoker->type == TCL_LOCATION_BC) {
-		/*
-		 * Note: Type BC => ctxPtr->data.eval.path is not used.
-		 * ctxPtr->data.tebc.codePtr is used instead.
-		 */
-
-		TclGetSrcInfoForPc(ctxPtr);
-		pc = 1;
-	    }
-
-	    script = Tcl_GetStringFromObj(objPtr, &numSrcBytes);
 
-	    if ((invoker->nline <= word) ||
-		    (invoker->line[word] < 0) ||
-		    (ctxPtr->type != TCL_LOCATION_SOURCE)) {
-		/*
-		 * Dynamic script, or dynamic context, force our own context.
-		 */
-
-		result = Tcl_EvalEx(interp, script, numSrcBytes, flags);
-	    } else {
-		/*
-		 * Absolute context to reuse.
-		 */
+	assert(invoker == NULL);
 
-		iPtr->invokeCmdFramePtr = ctxPtr;
-		iPtr->evalFlags |= TCL_EVAL_CTX;
+	iPtr->scriptCLLocPtr = TclContinuationsGet(objPtr);
 
-		result = TclEvalEx(interp, script, numSrcBytes, flags,
-			ctxPtr->line[word], NULL, script);
-	    }
-	    if (pc && (ctxPtr->type == TCL_LOCATION_SOURCE)) {
-		/*
-		 * Death of SrcInfo reference.
-		 */
+	Tcl_IncrRefCount(objPtr);
 
-		Tcl_DecrRefCount(ctxPtr->data.eval.path);
-	    }
-	    TclStackFree(interp, ctxPtr);
-	}
+	script = Tcl_GetStringFromObj(objPtr, &numSrcBytes);
+	result = Tcl_EvalEx(interp, script, numSrcBytes, flags);
 
-	/*
-	 * Now release the lock on the continuation line information, if any,
-	 * and restore the caller's settings.
-	 */
+	TclDecrRefCount(objPtr);
 
-	if (iPtr->scriptCLLocPtr) {
-	    Tcl_Release(iPtr->scriptCLLocPtr);
-	}
 	iPtr->scriptCLLocPtr = saveCLLocPtr;
-	TclDecrRefCount(objPtr);
 	return result;
     }
 }
diff --git a/generic/tclCompile.c b/generic/tclCompile.c
index 618b6fa..f5c8d41 100644
--- a/generic/tclCompile.c
+++ b/generic/tclCompile.c
@@ -713,9 +713,7 @@ TclSetByteCodeFromAny(
 
     clLocPtr = TclContinuationsGet(objPtr);
     if (clLocPtr) {
-	compEnv.clLoc = clLocPtr;
-	compEnv.clNext = &compEnv.clLoc->loc[0];
-	Tcl_Preserve(compEnv.clLoc);
+	compEnv.clNext = &clLocPtr->loc[0];
     }
 
     TclCompileScript(interp, stringPtr, length, &compEnv);
@@ -742,9 +740,7 @@ TclSetByteCodeFromAny(
 	TclInitCompileEnv(interp, &compEnv, stringPtr, length,
 		iPtr->invokeCmdFramePtr, iPtr->invokeWord);
 	if (clLocPtr) {
-	    compEnv.clLoc = clLocPtr;
-	    compEnv.clNext = &compEnv.clLoc->loc[0];
-	    Tcl_Preserve(compEnv.clLoc);
+	    compEnv.clNext = &clLocPtr->loc[0];
 	}
 	compEnv.atCmdStart = 2;		/* The disabling magic. */
 	TclCompileScript(interp, stringPtr, length, &compEnv);
@@ -1489,7 +1485,6 @@ TclInitCompileEnv(
      * data is available.
      */
 
-    envPtr->clLoc = NULL;
     envPtr->clNext = NULL;
 
     envPtr->auxDataArrayPtr = envPtr->staticAuxDataArraySpace;
@@ -1574,16 +1569,6 @@ TclFreeCompileEnv(
 	ReleaseCmdWordData(envPtr->extCmdMapPtr);
 	envPtr->extCmdMapPtr = NULL;
     }
-
-    /*
-     * If we used data about invisible continuation lines, then now is the
-     * time to release on our hold on it. The lock was set in function
-     * TclSetByteCodeFromAny(), found in this file.
-     */
-
-    if (envPtr->clLoc) {
-	Tcl_Release(envPtr->clLoc);
-    }
 }
 
 /*
diff --git a/generic/tclCompile.h b/generic/tclCompile.h
index beb28fd..5660055 100644
--- a/generic/tclCompile.h
+++ b/generic/tclCompile.h
@@ -365,10 +365,6 @@ typedef struct CompileEnv {
 				 * 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
-				 * line counter. */
     int *clNext;		/* If not NULL, it refers to the next slot in
 				 * clLoc to check for an invisible
 				 * continuation line. */
diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index 11e9920..f6072a1 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -8774,13 +8774,15 @@ TclGetSrcInfoForPc(
 {
     ByteCode *codePtr = (ByteCode *) cfPtr->data.tebc.codePtr;
 
-    if (cfPtr->cmd == NULL) {
+    assert(cfPtr->type == TCL_LOCATION_BC);
+    assert(cfPtr->cmd == NULL);
+
 	cfPtr->cmd = GetSrcInfoForPc(
 		(unsigned char *) cfPtr->data.tebc.pc, codePtr,
 		&cfPtr->len, NULL, NULL);
-    }
 
-    if (cfPtr->cmd != NULL) {
+    assert(cfPtr->cmd != NULL);
+    {
 	/*
 	 * We now have the command. We can get the srcOffset back and from
 	 * there find the list of word locations for this command.
diff --git a/generic/tclInt.h b/generic/tclInt.h
index cd4ab7d..99f1305 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -2201,7 +2201,6 @@ typedef struct Interp {
 
 #define TCL_ALLOW_EXCEPTIONS	4
 #define TCL_EVAL_FILE		2
-#define TCL_EVAL_CTX		8
 
 /*
  * Flag bits for Interp structures:
diff --git a/generic/tclObj.c b/generic/tclObj.c
index 542d6d1..930e1fd 100644
--- a/generic/tclObj.c
+++ b/generic/tclObj.c
@@ -97,7 +97,6 @@ typedef struct ThreadSpecificData {
 
 static Tcl_ThreadDataKey dataKey;
 
-static void             ContLineLocFree(char *clientData);
 static void             TclThreadFinalizeContLines(ClientData clientData);
 static ThreadSpecificData *TclGetContLineTable(void);
 
@@ -805,14 +804,7 @@ TclThreadFinalizeContLines(
 
     for (hPtr = Tcl_FirstHashEntry(tsdPtr->lineCLPtr, &hSearch);
 	    hPtr != NULL; hPtr = Tcl_NextHashEntry(&hSearch)) {
-	/*
-	 * We are not using Tcl_EventuallyFree (as in TclFreeObj()) because
-	 * here we can be sure that the compiler will not hold references to
-	 * the data in the hashtable, and using TEF might bork the
-	 * finalization sequence.
-	 */
-
-	ContLineLocFree(Tcl_GetHashValue(hPtr));
+	ckfree(Tcl_GetHashValue(hPtr));
 	Tcl_DeleteHashEntry(hPtr);
     }
     Tcl_DeleteHashTable(tsdPtr->lineCLPtr);
@@ -821,30 +813,6 @@ TclThreadFinalizeContLines(
 }
 
 /*
- *----------------------------------------------------------------------
- *
- * ContLineLocFree --
- *
- *	The freProc for continuation line location tables.
- *
- * Results:
- *	None.
- *
- * Side effects:
- *	Releases memory.
- *
- * TIP #280
- *----------------------------------------------------------------------
- */
-
-static void
-ContLineLocFree(
-    char *clientData)
-{
-    ckfree(clientData);
-}
-
-/*
  *--------------------------------------------------------------
  *
  * Tcl_RegisterObjType --
@@ -1405,7 +1373,7 @@ TclFreeObj(
 	if (tsdPtr->lineCLPtr) {
             hPtr = Tcl_FindHashEntry(tsdPtr->lineCLPtr, objPtr);
 	    if (hPtr) {
-		Tcl_EventuallyFree(Tcl_GetHashValue(hPtr), ContLineLocFree);
+		ckfree(Tcl_GetHashValue(hPtr));
 		Tcl_DeleteHashEntry(hPtr);
 	    }
 	}
@@ -1496,7 +1464,7 @@ TclFreeObj(
 	if (tsdPtr->lineCLPtr) {
             hPtr = Tcl_FindHashEntry(tsdPtr->lineCLPtr, objPtr);
 	    if (hPtr) {
-		Tcl_EventuallyFree(Tcl_GetHashValue(hPtr), ContLineLocFree);
+		ckfree(Tcl_GetHashValue(hPtr));
 		Tcl_DeleteHashEntry(hPtr);
 	    }
 	}
diff --git a/generic/tclParse.c b/generic/tclParse.c
index 6723d39..c5cb1d1 100644
--- a/generic/tclParse.c
+++ b/generic/tclParse.c
@@ -13,6 +13,7 @@
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  */
  
+#include <assert.h>
 #include "tclInt.h"
 #include "tclParse.h"
 
@@ -1578,16 +1579,13 @@ Tcl_ParseVar(
      * At this point we should have an object containing the value of a
      * variable. Just return the string from that object.
      *
-     * This should have returned the object for the user to manage, but
-     * instead we have some weak reference to the string value in the object,
-     * which is why we make sure the object exists after resetting the result.
-     * This isn't ideal, but it's the best we can do with the current
-     * documented interface. -- hobbs
+     * Since TclSubstTokens above returned TCL_OK, we know that objPtr
+     * is shared.  It is in both the interp result and the value of the
+     * variable.  Returning the string relies on that to be true.
      */
 
-    if (!Tcl_IsShared(objPtr)) {
-	Tcl_IncrRefCount(objPtr);
-    }
+    assert( Tcl_IsShared(objPtr) );
+
     Tcl_ResetResult(interp);
     return TclGetString(objPtr);
 }
diff --git a/tests/parse.test b/tests/parse.test
index 9f2d50b..01443c9 100644
--- a/tests/parse.test
+++ b/tests/parse.test
@@ -1118,6 +1118,12 @@ test parse-21.0 {Bug 1884496} testevent {
     testevent queue a head $::script
     vwait done
 } {}
+test parse-21.1 {TCL_EVAL_DIRECT coverage} testevent {
+    testevent queue a head {testevent delete a; \
+	set ::done [dict get [info frame 0] line]}
+    vwait done
+    set ::done
+} 2
 
 cleanupTests
 }