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authordgp <dgp@users.sourceforge.net>2013-07-16 20:48:37 (GMT)
committerdgp <dgp@users.sourceforge.net>2013-07-16 20:48:37 (GMT)
commit945323c68b1aaa265a1467ae1d1101a618e871a9 (patch)
tree29d87c13566461244ab919c82a880dcae4ac9bb4 /generic/tclCompile.c
parent01f1692c1f639eeb817ce6c51928195620872173 (diff)
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Streamline the housekeeping on the operands of INST_START_CMD.
For example, do only incr on success, not incr on attempt + decr on error.
Diffstat (limited to 'generic/tclCompile.c')
-rw-r--r--generic/tclCompile.c81
1 files changed, 32 insertions, 49 deletions
diff --git a/generic/tclCompile.c b/generic/tclCompile.c
index d82d728..6ac5fb9 100644
--- a/generic/tclCompile.c
+++ b/generic/tclCompile.c
@@ -1885,47 +1885,41 @@ CompileCmdCompileProc(
Tcl_Interp *interp,
Tcl_Parse *parsePtr,
Command *cmdPtr,
- int startCodeOffset,
CompileEnv *envPtr)
{
int savedNumCmds = envPtr->numCommands;
int startStackDepth = envPtr->currStackDepth;
- int update = 0;
+ int startCodeOffset = envPtr->codeNext - envPtr->codeStart;
+ int incrOffset = -1;
DefineLineInformation;
/*
- * Mark the start of the command; the proper bytecode
- * length will be updated later. There is no need to
- * do this for the first bytecode in the compile env,
- * as the check is done before calling
- * TclNRExecuteByteCode(). Do emit an INST_START_CMD
- * in special cases where the first bytecode is in a
- * loop, to insure that the corresponding command is
- * counted properly. Compilers for commands able to
- * produce such a beast (currently 'while 1' only) set
- * envPtr->atCmdStart to 0 in order to signal this
- * case. [Bug 1752146]
+ * Emit of the INST_START_CMD instruction is controlled by
+ * the value of envPtr->atCmdStart:
*
- * Note that the environment is initialised with
- * atCmdStart=1 to avoid emitting ISC for the first
- * command.
+ * atCmdStart == 2 : We are not using the INST_START_CMD instruction.
+ * atCmdStart == 1 : INST_START_CMD was the last instruction emitted.
+ * : We do not need to emit another. Instead we
+ * : increment the number of cmds started at it (except
+ * : for the special case at the start of a script.)
+ * atCmdStart == 0 : The last instruction was something else. We need
+ * : to emit INST_START_CMD here.
*/
- if (envPtr->atCmdStart == 1) {
- if (startCodeOffset) {
- /*
- * Increase the number of commands being
- * started at the current point. Note that
- * this depends on the exact layout of the
- * INST_START_CMD's operands, so be careful!
- */
-
- TclIncrUInt4AtPtr(envPtr->codeNext - 4, 1)
- }
- } else if (envPtr->atCmdStart == 0) {
+ switch (envPtr->atCmdStart) {
+ case 0:
TclEmitInstInt4(INST_START_CMD, 0, envPtr);
- TclEmitInt4(1, envPtr);
- update = 1;
+ incrOffset = envPtr->codeNext - envPtr->codeStart;
+ TclEmitInt4(0, envPtr);
+ break;
+ case 1:
+ if (envPtr->codeNext > envPtr->codeStart) {
+ incrOffset = envPtr->codeNext - 4 - envPtr->codeStart;
+ }
+ break;
+ case 2:
+ /* Nothing to do */
+ ;
}
if (TCL_OK == cmdPtr->compileProc(interp, parsePtr, cmdPtr, envPtr)) {
@@ -1947,30 +1941,20 @@ CompileCmdCompileProc(
parsePtr->tokenPtr->start, diff);
}
#endif
- if (update) {
+ if (incrOffset >= 0) {
/*
- * Fix the bytecode length.
+ * We successfully compiled a command. Increment the number
+ * of commands that start at the currently active INST_START_CMD.
*/
+ unsigned char *incrPtr = envPtr->codeStart + incrOffset;
+ unsigned char *startPtr = incrPtr - 5;
- unsigned char *fixPtr = envPtr->codeStart + startCodeOffset + 1;
- unsigned fixLen = envPtr->codeNext - fixPtr + 1;
-
- TclStoreInt4AtPtr(fixLen, fixPtr);
+ TclIncrUInt4AtPtr(incrPtr, 1);
+ TclStoreInt4AtPtr(envPtr->codeNext - startPtr, startPtr + 1);
}
return TCL_OK;
}
- if (envPtr->atCmdStart == 1 && startCodeOffset != 0) {
- /*
- * Decrease the number of commands being started
- * at the current point. Note that this depends on
- * the exact layout of the INST_START_CMD's
- * operands, so be careful!
- */
-
- TclIncrUInt4AtPtr(envPtr->codeNext - 4, -1);
- }
-
/*
* Restore numCommands, codeNext, and currStackDepth to their
* correct values, removing any commands compiled before the
@@ -2069,8 +2053,7 @@ CompileCommandTokens(
/* If cmdPtr != NULL, we will try to call cmdPtr->compileProc */
if (cmdPtr) {
- code = CompileCmdCompileProc(interp, parsePtr, cmdPtr,
- startCodeOffset, envPtr);
+ code = CompileCmdCompileProc(interp, parsePtr, cmdPtr, envPtr);
}
if (code == TCL_ERROR) {