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authordkf <donal.k.fellows@manchester.ac.uk>2007-08-19 22:27:34 (GMT)
committerdkf <donal.k.fellows@manchester.ac.uk>2007-08-19 22:27:34 (GMT)
commitcf8817bf14fed111b4cec85395a921345dfc0fdc (patch)
tree8ad26cf83b8f57d2b91deeea5b102ef9b44af05c /generic
parent2d71d4d051e14c5b84f251b888c67cbc7b0fee99 (diff)
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Make Miguel's overflow-detection more mnemonic with a macro.
Diffstat (limited to 'generic')
-rw-r--r--generic/tclExecute.c159
1 files changed, 86 insertions, 73 deletions
diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index 57296fb..a3d50a5 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.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: tclExecute.c,v 1.316 2007/08/19 18:59:15 msofer Exp $
+ * RCS: @(#) $Id: tclExecute.c,v 1.317 2007/08/19 22:27:35 dkf Exp $
*/
#include "tclInt.h"
@@ -87,7 +87,7 @@ int tclTraceExec = 0;
* expression opcodes (e.g., INST_LOR) in tclCompile.h.
*
* Does not include the string for INST_EXPON (and beyond), as that is
- * disjoint for backward-compatability reasons
+ * disjoint for backward-compatability reasons.
*/
static const char *operatorStrings[] = {
@@ -119,7 +119,7 @@ long tclObjsShared[TCL_MAX_SHARED_OBJ_STATS] = { 0, 0, 0, 0, 0 };
#endif /* TCL_COMPILE_STATS */
/*
- * Support pre-8.5 bytecodes unless specifically requested otherwise
+ * Support pre-8.5 bytecodes unless specifically requested otherwise.
*/
#ifndef TCL_SUPPORT_84_BYTECODE
@@ -422,6 +422,16 @@ VarHashCreateVar(TclVarHashTable *tablePtr, Tcl_Obj *key, int *newPtr)
#endif
/*
+ * Macro used to make the check for type overflow more mnemonic. This works by
+ * comparing sign bits; the rest of the word is irrelevant. The ANSI C
+ * "prototype" (where inttype_t is any integer type) is:
+ *
+ * MODULE_SCOPE int Overflowing(inttype_t a, inttype_t b, inttype_t sum);
+ */
+
+#define Overflowing(a,b,sum) ((((a)^(b)) >= 0) && (((a)^(sum)) < 0))
+
+/*
* Custom object type only used in this file; values of its type should never
* be seen by user scripts.
*/
@@ -447,7 +457,8 @@ static ExceptionRange * GetExceptRangeForPc(unsigned char *pc, int catchOnly,
ByteCode *codePtr);
static const char * GetSrcInfoForPc(unsigned char *pc, ByteCode *codePtr,
int *lengthPtr);
-static Tcl_Obj ** GrowEvaluationStack(ExecEnv *eePtr, int growth, int move);
+static Tcl_Obj ** GrowEvaluationStack(ExecEnv *eePtr, int growth,
+ int move);
static void IllegalExprOperandType(Tcl_Interp *interp,
unsigned char *pc, Tcl_Obj *opndPtr);
static void InitByteCodeExecution(Tcl_Interp *interp);
@@ -458,13 +469,10 @@ static void ValidatePcAndStackTop(ByteCode *codePtr,
unsigned char *pc, int stackTop,
int stackLowerBound, int checkStack);
#endif /* TCL_COMPILE_DEBUG */
-
static void DeleteExecStack(ExecStack *esPtr);
-
/* Useful elsewhere, make available in tclInt.h or stubs? */
static Tcl_Obj ** StackAllocWords(Tcl_Interp *interp, int numWords);
static Tcl_Obj ** StackReallocWords(Tcl_Interp *interp, int numWords);
-
/*
*----------------------------------------------------------------------
@@ -693,7 +701,7 @@ GrowEvaluationStack(
* store it in esPtr as the current marker. Return a pointer to one
* word past the marker.
*/
-
+
esPtr->markerPtr = ++esPtr->tosPtr;
*esPtr->markerPtr = (Tcl_Obj *) markerPtr;
return esPtr->markerPtr + 1;
@@ -760,7 +768,7 @@ GrowEvaluationStack(
* this is the first marker in this stack and that rewinding to here
* should actually be a return to the previous stack.
*/
-
+
esPtr->stackWords[0] = NULL;
esPtr->markerPtr = esPtr->tosPtr = &esPtr->stackWords[0];
@@ -785,10 +793,10 @@ GrowEvaluationStack(
/*
*--------------------------------------------------------------
*
- * TclStackAlloc --
+ * TclStackAlloc, TclStackRealloc, TclStackFree --
*
* Allocate memory from the execution stack; it has to be returned later
- * with a call to TclStackFree
+ * with a call to TclStackFree.
*
* Results:
* A pointer to the first byte allocated, or panics if the allocation did
@@ -809,7 +817,7 @@ StackAllocWords(
* Note that GrowEvaluationStack sets a marker in the stack. This marker
* is read when rewinding, e.g., by TclStackFree.
*/
-
+
Interp *iPtr = (Interp *) interp;
ExecEnv *eePtr = iPtr->execEnvPtr;
Tcl_Obj **resPtr = GrowEvaluationStack(eePtr, numWords, 0);
@@ -850,14 +858,14 @@ TclStackFree(
* Rewind the stack to the previous marker position. The current marker,
* as set in the last call to GrowEvaluationStack, contains a pointer to
* the previous marker.
- */
+ */
eePtr = iPtr->execEnvPtr;
esPtr = eePtr->execStackPtr;
markerPtr = esPtr->markerPtr;
if ((markerPtr+1) != (Tcl_Obj **)freePtr) {
- Tcl_Panic("TclStackFree: incorrect freePtr. Call out of sequence?");
+ Tcl_Panic("TclStackFree: incorrect freePtr. Call out of sequence?");
}
esPtr->tosPtr = markerPtr-1;
@@ -918,7 +926,7 @@ TclStackRealloc(
markerPtr = esPtr->markerPtr;
if ((markerPtr+1) != (Tcl_Obj **)ptr) {
- Tcl_Panic("TclStackRealloc: incorrect ptr. Call out of sequence?");
+ Tcl_Panic("TclStackRealloc: incorrect ptr. Call out of sequence?");
}
numWords = (numBytes + (sizeof(Tcl_Obj *) - 1))/sizeof(Tcl_Obj *);
@@ -1029,7 +1037,7 @@ Tcl_ExprObj(
}
if (objPtr->typePtr != &tclByteCodeType) {
/*
- * TIP #280: No invoker (yet) - Expression compilation
+ * TIP #280: No invoker (yet) - Expression compilation.
*/
TclInitCompileEnv(interp, &compEnv, string, length, NULL, 0);
@@ -1225,8 +1233,9 @@ TclCompEvalObj(
codePtr->compileEpoch = iPtr->compileEpoch;
} else {
/*
- * This byteCode is invalid: free it and recompile
+ * This byteCode is invalid: free it and recompile.
*/
+
objPtr->typePtr->freeIntRepProc(objPtr);
goto recompileObj;
}
@@ -1317,11 +1326,12 @@ TclIncrObj(
long sum = augend + addend;
/*
- * Overflow when (augend and sum have different sign) and
- * (augend and i have the same sign)
+ * Overflow when (augend and sum have different sign) and (augend and
+ * addend have the same sign). This is encapsulated in the Overflowing
+ * macro.
*/
-
- if (((augend^sum) >= 0) || ((augend^addend) < 0) ) {
+
+ if (!Overflowing(augend, addend, sum)) {
TclSetLongObj(valuePtr, sum);
return TCL_OK;
}
@@ -1369,7 +1379,7 @@ TclIncrObj(
* Check for overflow.
*/
- if (((w1^sum) >= 0) || (w1^w2) < 0) {
+ if (!Overflowing(w1, w2, sum)) {
Tcl_SetWideIntObj(valuePtr, sum);
return TCL_OK;
}
@@ -1579,8 +1589,9 @@ TclExecuteByteCode(
case 0:
/*
* We really want to do nothing now, but this is needed for some
- * compilers (SunPro CC)
+ * compilers (SunPro CC).
*/
+
break;
}
}
@@ -1588,7 +1599,7 @@ TclExecuteByteCode(
#ifdef TCL_COMPILE_DEBUG
/*
- * Skip the stack depth check if an expansion is in progress
+ * Skip the stack depth check if an expansion is in progress.
*/
ValidatePcAndStackTop(codePtr, pc, CURR_DEPTH, 0,
@@ -1647,13 +1658,13 @@ TclExecuteByteCode(
* mispredictions, seems to improve runtime by 5% to 15%, and (amazingly!)
* reduces total obj size.
*/
-
+
if (*pc == INST_LOAD_SCALAR1) {
goto instLoadScalar1;
} else if (*pc == INST_PUSH1) {
goto instPush1Peephole;
}
-
+
switch (*pc) {
case INST_RETURN_IMM: {
int code = TclGetInt4AtPtr(pc+1);
@@ -2058,7 +2069,7 @@ TclExecuteByteCode(
#ifndef TCL_COMPILE_DEBUG
if (*(pc+pcAdjustment) == INST_POP) {
- NEXT_INST_V((pcAdjustment+1), objc, 0);
+ NEXT_INST_V((pcAdjustment+1), objc, 0);
}
#endif
/*
@@ -2357,8 +2368,8 @@ TclExecuteByteCode(
case INST_LOAD_ARRAY_STK:
cleanup = 2;
- part2Ptr = OBJ_AT_TOS; /* element name */
- objPtr = OBJ_UNDER_TOS; /* array name */
+ part2Ptr = OBJ_AT_TOS; /* element name */
+ objPtr = OBJ_UNDER_TOS; /* array name */
TRACE(("\"%.30s(%.30s)\" => ", O2S(objPtr), O2S(part2Ptr)));
goto doLoadStk;
@@ -2366,18 +2377,20 @@ TclExecuteByteCode(
case INST_LOAD_SCALAR_STK:
cleanup = 1;
part2Ptr = NULL;
- objPtr = OBJ_AT_TOS; /* variable name */
+ objPtr = OBJ_AT_TOS; /* variable name */
TRACE(("\"%.30s\" => ", O2S(objPtr)));
doLoadStk:
part1Ptr = objPtr;
- varPtr = TclObjLookupVarEx(interp, part1Ptr, part2Ptr, TCL_LEAVE_ERR_MSG,
- "read", /*createPart1*/ 0, /*createPart2*/ 1, &arrayPtr);
+ varPtr = TclObjLookupVarEx(interp, part1Ptr, part2Ptr,
+ TCL_LEAVE_ERR_MSG, "read", /*createPart1*/0, /*createPart2*/1,
+ &arrayPtr);
if (varPtr) {
if (TclIsVarDirectReadable2(varPtr, arrayPtr)) {
/*
* No errors, no traces: just get the value.
*/
+
objResultPtr = varPtr->value.objPtr;
TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
NEXT_INST_V(1, cleanup, 1);
@@ -2462,7 +2475,7 @@ TclExecuteByteCode(
storeFlags = TCL_LEAVE_ERR_MSG;
part1Ptr = NULL;
goto doStoreArrayDirectFailed;
-
+
case INST_STORE_SCALAR4:
opnd = TclGetUInt4AtPtr(pc+1);
pcAdjustment = 5;
@@ -2491,23 +2504,23 @@ TclExecuteByteCode(
if (valuePtr != NULL) {
TclDecrRefCount(valuePtr);
}
- objResultPtr = OBJ_AT_TOS;
+ objResultPtr = OBJ_AT_TOS;
varPtr->value.objPtr = objResultPtr;
#ifndef TCL_COMPILE_DEBUG
if (*(pc+pcAdjustment) == INST_POP) {
tosPtr--;
- NEXT_INST_F((pcAdjustment+1), 0, 0);
+ NEXT_INST_F((pcAdjustment+1), 0, 0);
}
#else
TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
#endif
- Tcl_IncrRefCount(objResultPtr);
- NEXT_INST_F(pcAdjustment, 0, 0);
+ Tcl_IncrRefCount(objResultPtr);
+ NEXT_INST_F(pcAdjustment, 0, 0);
}
storeFlags = TCL_LEAVE_ERR_MSG;
part1Ptr = NULL;
goto doStoreScalar;
-
+
case INST_LAPPEND_STK:
valuePtr = OBJ_AT_TOS; /* value to append */
part2Ptr = NULL;
@@ -2607,7 +2620,7 @@ TclExecuteByteCode(
}
cleanup = 2;
part1Ptr = NULL;
-
+
doStoreArrayDirectFailed:
varPtr = TclLookupArrayElement(interp, part1Ptr, part2Ptr,
TCL_LEAVE_ERR_MSG, "set", 1, 1, arrayPtr, opnd);
@@ -2644,7 +2657,7 @@ TclExecuteByteCode(
pcAdjustment = 2;
storeFlags = (TCL_LEAVE_ERR_MSG | TCL_APPEND_VALUE);
goto doStoreScalar;
-
+
doStoreScalar:
valuePtr = OBJ_AT_TOS;
varPtr = &(compiledLocals[opnd]);
@@ -2670,8 +2683,7 @@ TclExecuteByteCode(
TRACE_APPEND(("%.30s\n", O2S(objResultPtr)));
NEXT_INST_V(pcAdjustment, cleanup, 1);
} else {
- TRACE_APPEND(("ERROR: %.30s\n",
- O2S(Tcl_GetObjResult(interp))));
+ TRACE_APPEND(("ERROR: %.30s\n", O2S(Tcl_GetObjResult(interp))));
result = TCL_ERROR;
goto checkForCatch;
}
@@ -2807,10 +2819,11 @@ TclExecuteByteCode(
/*
* Overflow when (augend and sum have different sign) and
- * (augend and i have the same sign)
+ * (augend and i have the same sign). This is encapsulated
+ * in the Overflowing macro.
*/
- if (((augend^sum) >= 0) || ((augend^i) < 0) ) {
+ if (!Overflowing(augend, i, sum)) {
TRACE(("%u %ld => ", opnd, i));
if (Tcl_IsShared(objPtr)) {
objPtr->refCount--; /* We know it's shared. */
@@ -2858,7 +2871,7 @@ TclExecuteByteCode(
* Check for overflow.
*/
- if (((w^sum) >= 0) || ((w^i) < 0)) {
+ if (!Overflowing(w, i, sum)) {
TRACE(("%u %ld => ", opnd, i));
if (Tcl_IsShared(objPtr)) {
objPtr->refCount--; /* We know it's shared. */
@@ -2978,7 +2991,7 @@ TclExecuteByteCode(
result = TclObjGetFrame(interp, OBJ_UNDER_TOS, &framePtr);
if (result != -1) {
/*
- * Locate the other variable
+ * Locate the other variable.
*/
savedFramePtr = iPtr->varFramePtr;
@@ -3003,7 +3016,7 @@ TclExecuteByteCode(
/*createPart1*/ 1, /*createPart2*/ 1, &varPtr);
if (otherPtr) {
/*
- * Do the [variable] magic
+ * Do the [variable] magic.
*/
TclSetVarNamespaceVar(otherPtr);
@@ -3022,7 +3035,7 @@ TclExecuteByteCode(
result = TclGetNamespaceFromObj(interp, OBJ_UNDER_TOS, &nsPtr);
if ((result == TCL_OK) && nsPtr) {
/*
- * Locate the other variable
+ * Locate the other variable.
*/
savedNsPtr = (Tcl_Namespace *) iPtr->varFramePtr->nsPtr;
@@ -3283,20 +3296,20 @@ TclExecuteByteCode(
Tcl_Obj *valuePtr, *value2Ptr;
/*
- * Pop the two operands
+ * Pop the two operands.
*/
value2Ptr = OBJ_AT_TOS;
valuePtr = OBJ_UNDER_TOS;
/*
- * Extract the desired list element
+ * Extract the desired list element.
*/
objResultPtr = TclLindexList(interp, valuePtr, value2Ptr);
if (objResultPtr) {
/*
- * Stash the list element on the stack
+ * Stash the list element on the stack.
*/
TRACE(("%.20s %.20s => %s\n",
@@ -3318,7 +3331,7 @@ TclExecuteByteCode(
Tcl_Obj *valuePtr;
/*
- * Pop the list and get the index
+ * Pop the list and get the index.
*/
valuePtr = OBJ_AT_TOS;
@@ -3377,13 +3390,14 @@ TclExecuteByteCode(
numIdx, &OBJ_AT_DEPTH(numIdx - 1));
/*
- * Check for errors
+ * Check for errors.
*/
if (objResultPtr) {
/*
- * Set result
+ * Set result.
*/
+
TRACE(("%d => %s\n", opnd, O2S(objResultPtr)));
NEXT_INST_V(5, opnd, -1);
} else {
@@ -3421,19 +3435,19 @@ TclExecuteByteCode(
valuePtr = OBJ_AT_TOS;
/*
- * Compute the new variable value
+ * Compute the new variable value.
*/
objResultPtr = TclLsetFlat(interp, value2Ptr, numIdx,
&OBJ_AT_DEPTH(numIdx), valuePtr);
/*
- * Check for errors
+ * Check for errors.
*/
if (objResultPtr) {
/*
- * Set result
+ * Set result.
*/
TRACE(("%d => %s\n", opnd, O2S(objResultPtr)));
@@ -3463,25 +3477,25 @@ TclExecuteByteCode(
Tcl_DecrRefCount(objPtr); /* This one should be done here */
/*
- * Get the new element value, and the index list
+ * Get the new element value, and the index list.
*/
valuePtr = OBJ_AT_TOS;
value2Ptr = OBJ_UNDER_TOS;
/*
- * Compute the new variable value
+ * Compute the new variable value.
*/
objResultPtr = TclLsetList(interp, objPtr, value2Ptr, valuePtr);
/*
- * Check for errors
+ * Check for errors.
*/
if (objResultPtr) {
/*
- * Set result
+ * Set result.
*/
TRACE(("=> %s\n", O2S(objResultPtr)));
@@ -3501,7 +3515,7 @@ TclExecuteByteCode(
Tcl_Obj **listv, *valuePtr;
/*
- * Pop the list and get the indices
+ * Pop the list and get the indices.
*/
valuePtr = OBJ_AT_TOS;
@@ -3517,7 +3531,7 @@ TclExecuteByteCode(
/*
* Skip a lot of work if we're about to throw the result away (common
- * with uses of [lassign].)
+ * with uses of [lassign]).
*/
if (result == TCL_OK) {
@@ -3720,7 +3734,7 @@ TclExecuteByteCode(
case INST_STR_CMP: {
/*
- * String compare
+ * String compare.
*/
const char *s1, *s2;
@@ -3845,8 +3859,9 @@ TclExecuteByteCode(
case INST_STR_INDEX: {
/*
- * String compare
+ * String compare.
*/
+
int index, length;
char *bytes;
Tcl_Obj *valuePtr, *value2Ptr;
@@ -4307,7 +4322,7 @@ TclExecuteByteCode(
}
if ((l2 == 1) || (l2 == -1)) {
/*
- * Div. by |1| always yields remainder of 0
+ * Div. by |1| always yields remainder of 0.
*/
objResultPtr = constants[0];
@@ -4319,7 +4334,7 @@ TclExecuteByteCode(
l1 = *((const long *)ptr1);
if (l1 == 0) {
/*
- * 0 % (non-zero) always yields remainder of 0
+ * 0 % (non-zero) always yields remainder of 0.
*/
objResultPtr = constants[0];
@@ -4335,7 +4350,6 @@ TclExecuteByteCode(
/*
* Force Tcl's integer division rules.
- *
* TODO: examine for logic simplification
*/
@@ -4420,7 +4434,6 @@ TclExecuteByteCode(
/*
* Force Tcl's integer division rules.
- *
* TODO: examine for logic simplification
*/
@@ -4602,7 +4615,7 @@ TclExecuteByteCode(
}
} else {
/*
- * Quickly force large right shifts to 0 or -1
+ * Quickly force large right shifts to 0 or -1.
*/
TRACE(("%s %s => ", O2S(valuePtr), O2S(value2Ptr)));
@@ -5271,7 +5284,7 @@ TclExecuteByteCode(
* Check for overflow.
*/
- if (((w1^wResult) < 0) && ((w1^w2) >= 0)) {
+ if (Overflowing(w1, w2, wResult)) {
goto overflow;
}
}
@@ -5287,7 +5300,7 @@ TclExecuteByteCode(
* Must check for overflow.
*/
- if (((w1^wResult) < 0) && ((w1^w2) < 0)) {
+ if (Overflowing(w1, w2, wResult)) {
goto overflow;
}
}
@@ -6420,7 +6433,7 @@ TclExecuteByteCode(
goto checkForCatch;
/*
- * Block for variables needed to process exception returns
+ * Block for variables needed to process exception returns.
*/
{