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TableGen: avoid dereferencing nullptr variable 

ARM64 ended up reaching odder parts of TableGen alias generation than
current backends and caused a segfault.

llvm-svn: 205089
This commit is contained in:
Tim Northover 2014-03-29 09:03:22 +00:00
parent 753eca0f78
commit 3e38d290c8
1 changed files with 10 additions and 6 deletions
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16
llvm/utils/TableGen/CodeGenInstruction.cpp
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@ -436,6 +436,7 @@ bool CodeGenInstAlias::tryAliasOpMatch(DagInit *Result, unsigned AliasOpNo,
ResultOperand &ResOp) {
Init *Arg = Result->getArg(AliasOpNo);
DefInit *ADI = dyn_cast<DefInit>(Arg);
Record *ResultRecord = ADI ? ADI->getDef() : 0;
if (ADI && ADI->getDef() == InstOpRec) {
// If the operand is a record, it must have a name, and the record type
@ -443,19 +444,25 @@ bool CodeGenInstAlias::tryAliasOpMatch(DagInit *Result, unsigned AliasOpNo,
if (Result->getArgName(AliasOpNo).empty())
PrintFatalError(Loc, "result argument #" + utostr(AliasOpNo) +
" must have a name!");
ResOp = ResultOperand(Result->getArgName(AliasOpNo), ADI->getDef());
ResOp = ResultOperand(Result->getArgName(AliasOpNo), ResultRecord);
return true;
}
// For register operands, the source register class can be a subclass
// of the instruction register class, not just an exact match.
if (InstOpRec->isSubClassOf("RegisterOperand"))
InstOpRec = InstOpRec->getValueAsDef("RegClass");
if (ADI && ADI->getDef()->isSubClassOf("RegisterOperand"))
ADI = ADI->getDef()->getValueAsDef("RegClass")->getDefInit();
if (ADI && ADI->getDef()->isSubClassOf("RegisterClass")) {
if (!InstOpRec->isSubClassOf("RegisterClass"))
return false;
if (!T.getRegisterClass(InstOpRec)
.hasSubClass(&T.getRegisterClass(ADI->getDef())))
return false;
ResOp = ResultOperand(Result->getArgName(AliasOpNo), ADI->getDef());
ResOp = ResultOperand(Result->getArgName(AliasOpNo), ResultRecord);
return true;
}
@ -468,9 +475,6 @@ bool CodeGenInstAlias::tryAliasOpMatch(DagInit *Result, unsigned AliasOpNo,
InstOpRec = cast<DefInit>(DI->getArg(0))->getDef();
}
if (InstOpRec->isSubClassOf("RegisterOperand"))
InstOpRec = InstOpRec->getValueAsDef("RegClass");
if (!InstOpRec->isSubClassOf("RegisterClass"))
return false;
@ -484,7 +488,7 @@ bool CodeGenInstAlias::tryAliasOpMatch(DagInit *Result, unsigned AliasOpNo,
PrintFatalError(Loc, "result fixed register argument must "
"not have a name!");
ResOp = ResultOperand(ADI->getDef());
ResOp = ResultOperand(ResultRecord);
return true;
}