From 5b08f1d1ef025223ce9bc15d06dbdb88c247822a Mon Sep 17 00:00:00 2001
From: mig <mig>
Date: Tue, 10 Dec 2013 11:38:17 +0000
Subject: new INST_LMAP_COLLECT, speeds up lmap and eliminates the need for a
 temp var

---
 generic/tclCompCmds.c | 42 ++++++++++++++----------------------------
 generic/tclCompile.c  |  1 +
 generic/tclCompile.h  |  3 ++-
 generic/tclExecute.c  | 19 +++++++++++++++++++
 4 files changed, 36 insertions(+), 29 deletions(-)

diff --git a/generic/tclCompCmds.c b/generic/tclCompCmds.c
index bdab2ff..cd43cfc 100644
--- a/generic/tclCompCmds.c
+++ b/generic/tclCompCmds.c
@@ -2458,8 +2458,6 @@ CompileEachloopCmd(
     ForeachInfo *infoPtr;	/* Points to the structure describing this
 				 * foreach command. Stored in a AuxData
 				 * record in the ByteCode. */
-    int collectVar = -1;	/* Index of temp var holding the result var
-				 * index. */
     
     Tcl_Token *tokenPtr, *bodyTokenPtr;
     int jumpBackOffset, infoIndex, range;
@@ -2575,13 +2573,6 @@ CompileEachloopCmd(
      * We will compile the foreach command.
      */
 
-    if (collect == TCL_EACH_COLLECT) {
-	collectVar = AnonymousLocal(envPtr);
-	if (collectVar < 0) {
-	    return TCL_ERROR;
-	}
-    }
-	    
     code = TCL_OK;
 
     /*
@@ -2612,6 +2603,14 @@ CompileEachloopCmd(
     infoIndex = TclCreateAuxData(infoPtr, &tclNewForeachInfoType, envPtr);
 
     /*
+     * Create the collecting object, unshared.
+     */
+    
+    if (collect == TCL_EACH_COLLECT) {
+	TclEmitInstInt4(INST_LIST, 0, envPtr);
+    }
+	    
+    /*
      * Evaluate each value list and leave it on stack.
      */
 
@@ -2623,16 +2622,6 @@ CompileEachloopCmd(
 	}
     }
 
-    /*
-     * Create temporary variable to capture return values from loop body.
-     */
-     
-    if (collect == TCL_EACH_COLLECT) {
-	PushStringLiteral(envPtr, "");
-	Emit14Inst(		INST_STORE_SCALAR, collectVar,	envPtr);
-	TclEmitOpcode(		INST_POP,			envPtr);
-    }
-
     TclEmitInstInt4(INST_FOREACH_START, infoIndex, envPtr);
     
     /*
@@ -2646,9 +2635,10 @@ CompileEachloopCmd(
     ExceptionRangeEnds(envPtr, range);
     
     if (collect == TCL_EACH_COLLECT) {
-	Emit14Inst(		INST_LAPPEND_SCALAR, collectVar,envPtr);
+	TclEmitOpcode(INST_LMAP_COLLECT, envPtr);
+    } else {
+	TclEmitOpcode(		INST_POP,			envPtr);
     }
-    TclEmitOpcode(		INST_POP,			envPtr);
 
     /*
      * Bottom of loop code: assign each loop variable and check whether
@@ -2672,15 +2662,11 @@ CompileEachloopCmd(
     infoPtr->loopCtTemp = -jumpBackOffset;
 
     /*
-     * The command's result is an empty string if not collecting, or the
-     * list of results from evaluating the loop body.
+     * The command's result is an empty string if not collecting. If
+     * collecting, it is automatically left on stack after FOREACH_END.
      */
 
-    if (collect == TCL_EACH_COLLECT) {
-	Emit14Inst(		INST_LOAD_SCALAR, collectVar,	envPtr);
-	TclEmitInstInt1(INST_UNSET_SCALAR, 0,			envPtr);
-	TclEmitInt4(		collectVar,			envPtr);
-    } else {
+    if (collect != TCL_EACH_COLLECT) {
 	PushStringLiteral(envPtr, "");
     }
     
diff --git a/generic/tclCompile.c b/generic/tclCompile.c
index 7cd9796..c7b7875 100644
--- a/generic/tclCompile.c
+++ b/generic/tclCompile.c
@@ -554,6 +554,7 @@ InstructionDesc const tclInstructionTable[] = {
     {"foreach_step",	  1,    0,         0,	{OPERAND_NONE}},
 	/* "Step" or begin next iteration of foreach loop. */
     {"foreach_end",	  1,    0,         0,	{OPERAND_NONE}},
+    {"lmap_collect",	  1,    0,         0,	{OPERAND_NONE}},
 
     {NULL, 0, 0, 0, {OPERAND_NONE}}
 };
diff --git a/generic/tclCompile.h b/generic/tclCompile.h
index 8b1724b..7f62849 100644
--- a/generic/tclCompile.h
+++ b/generic/tclCompile.h
@@ -773,9 +773,10 @@ typedef struct ByteCode {
 #define INST_FOREACH_START              166
 #define INST_FOREACH_STEP               167
 #define INST_FOREACH_END                168
+#define INST_LMAP_COLLECT               169
 
 /* The last opcode */
-#define LAST_INST_OPCODE		168
+#define LAST_INST_OPCODE		169
 
 /*
  * Table describing the Tcl bytecode instructions: their name (for displaying
diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index a3083bc..9261f19 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -6345,6 +6345,25 @@ TEBCresume(
 	infoPtr = tmpPtr->internalRep.otherValuePtr;
 	numLists = infoPtr->numLists;
 	NEXT_INST_V(1, numLists+2, 0);
+
+    case INST_LMAP_COLLECT:
+	/*
+	 * This instruction is only issued by lmap. The stack is:
+	 *   - result
+	 *   - infoPtr
+	 *   - loop counters
+	 *   - valLists
+	 *   - collecting obj (unshared)
+	 * The instruction lappends the result to the collecting obj.
+	 */
+
+	tmpPtr = OBJ_AT_DEPTH(1);
+	infoPtr = tmpPtr->internalRep.otherValuePtr;
+	numLists = infoPtr->numLists;
+	
+	objPtr = OBJ_AT_DEPTH(3 + numLists);
+	Tcl_ListObjAppendElement(NULL, objPtr, OBJ_AT_TOS);
+	NEXT_INST_F(1, 1, 0);
     }
 
     case INST_BEGIN_CATCH4:
-- 
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