[llvm] r183630 - tblgen: always lookup values from the original vector as it could be grown under our feet.

[Benjamin Kramer]

On 10.06.2013, at 22:08, David Blaikie <dblaikie at gmail.com> wrote:

> On Sun, Jun 9, 2013 at 8:20 AM, Benjamin Kramer
> <benny.kra at googlemail.com> wrote:
>> Author: d0k
>> Date: Sun Jun  9 10:20:23 2013
>> New Revision: 183630
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=183630&view=rev
>> Log:
>> tblgen: always lookup values from the original vector as it could be grown under our feet.
>> 
>> PR16281.
>> 
>> Modified:
>>    llvm/trunk/utils/TableGen/CodeGenSchedule.cpp
>> 
>> Modified: llvm/trunk/utils/TableGen/CodeGenSchedule.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/TableGen/CodeGenSchedule.cpp?rev=183630&r1=183629&r2=183630&view=diff
>> ==============================================================================
>> --- llvm/trunk/utils/TableGen/CodeGenSchedule.cpp (original)
>> +++ llvm/trunk/utils/TableGen/CodeGenSchedule.cpp Sun Jun  9 10:20:23 2013
>> @@ -890,9 +890,9 @@ void CodeGenSchedModels::inferFromItinCl
>> 
>> /// Infer classes from per-processor InstReadWrite definitions.
>> void CodeGenSchedModels::inferFromInstRWs(unsigned SCIdx) {
>> -  const RecVec &RWDefs = SchedClasses[SCIdx].InstRWs;
>> -  for (RecIter RWI = RWDefs.begin(), RWE = RWDefs.end(); RWI != RWE; ++RWI) {
>> -    const RecVec *InstDefs = Sets.expand(*RWI);
>> +  for (unsigned I = 0, E = SchedClasses[SCIdx].InstRWs.size(); I != E; ++I) {
>> +    Record *Rec = SchedClasses[SCIdx].InstRWs[I];
> 
> Does this deserve a comment? Would it be at all worth putting in an
> assert to demonstrate that the size only ever increases (retrieve the
> size before the loop, assert that it's <= the size at the start of the
> loop, etc) so we can't accidentally skip the loop termination
> condition?

An assert is a great idea, r183690.

- Ben

> 
>> +    const RecVec *InstDefs = Sets.expand(Rec);
>>     RecIter II = InstDefs->begin(), IE = InstDefs->end();
>>     for (; II != IE; ++II) {
>>       if (InstrClassMap[*II] == SCIdx)
>> @@ -903,10 +903,10 @@ void CodeGenSchedModels::inferFromInstRW
>>     if (II == IE)
>>       continue;
>>     IdxVec Writes, Reads;
>> -    findRWs((*RWI)->getValueAsListOfDefs("OperandReadWrites"), Writes, Reads);
>> -    unsigned PIdx = getProcModel((*RWI)->getValueAsDef("SchedModel")).Index;
>> +    findRWs(Rec->getValueAsListOfDefs("OperandReadWrites"), Writes, Reads);
>> +    unsigned PIdx = getProcModel(Rec->getValueAsDef("SchedModel")).Index;
>>     IdxVec ProcIndices(1, PIdx);
>> -    inferFromRW(Writes, Reads, SCIdx, ProcIndices);
>> +    inferFromRW(Writes, Reads, SCIdx, ProcIndices); // May mutate SchedClasses.
>>   }
>> }
>> 
>> 
>> 
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