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TableGen: Explicitly forbid self-references to field members 

Summary:
Otherwise, patterns like in the test case produce cryptic error
messages about fields being resolved incompletely.

Change-Id: I713c0191f00fe140ad698675803ab1f8823dc5bd

Reviewers: arsenm, craig.topper, tra, MartinO

Subscribers: wdng, llvm-commits

Differential Revision: https://reviews.llvm.org/D44476

llvm-svn: 327850
This commit is contained in:
Nicolai Haehnle 2018-03-19 14:14:28 +00:00
parent 4186cc7c08
commit 2ad19016c0
4 changed files with 20 additions and 5 deletions
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2
llvm/include/llvm/TableGen/Record.h
View File

@ -1200,7 +1200,7 @@ public:
Init *getBit(unsigned Bit) const override; Init *getBit(unsigned Bit) const override;
Init *resolveReferences(Resolver &R) const override; Init *resolveReferences(Resolver &R) const override;
Init *Fold() const; Init *Fold(Record *CurRec) const;
std::string getAsString() const override { std::string getAsString() const override {
return Rec->getAsString() + "." + FieldName->getValue().str(); return Rec->getAsString() + "." + FieldName->getValue().str();

12
llvm/lib/TableGen/Record.cpp
View File

@ -1684,13 +1684,19 @@ Init *FieldInit::getBit(unsigned Bit) const {
Init *FieldInit::resolveReferences(Resolver &R) const { Init *FieldInit::resolveReferences(Resolver &R) const {
Init *NewRec = Rec->resolveReferences(R); Init *NewRec = Rec->resolveReferences(R);
if (NewRec != Rec) if (NewRec != Rec)
return FieldInit::get(NewRec, FieldName)->Fold(); return FieldInit::get(NewRec, FieldName)->Fold(R.getCurrentRecord());
return const_cast<FieldInit *>(this); return const_cast<FieldInit *>(this);
} }
Init *FieldInit::Fold() const { Init *FieldInit::Fold(Record *CurRec) const {
if (DefInit *DI = dyn_cast<DefInit>(Rec)) { if (DefInit *DI = dyn_cast<DefInit>(Rec)) {
Init *FieldVal = DI->getDef()->getValue(FieldName)->getValue(); Record *Def = DI->getDef();
if (Def == CurRec)
PrintFatalError(CurRec->getLoc(),
Twine("Attempting to access field '") +
FieldName->getAsUnquotedString() + "' of '" +
Rec->getAsString() + "' is a forbidden self-reference");
Init *FieldVal = Def->getValue(FieldName)->getValue();
if (FieldVal->isComplete()) if (FieldVal->isComplete())
return FieldVal; return FieldVal;
} }

2
llvm/lib/TableGen/TGParser.cpp
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@ -1943,7 +1943,7 @@ Init *TGParser::ParseValue(Record *CurRec, RecTy *ItemType, IDParseMode Mode) {
Result->getAsString() + "'"); Result->getAsString() + "'");
return nullptr; return nullptr;
} }
Result = FieldInit::get(Result, FieldName)->Fold(); Result = FieldInit::get(Result, FieldName)->Fold(CurRec);
Lex.Lex(); // eat field name Lex.Lex(); // eat field name
break; break;
} }

9
llvm/test/TableGen/self-reference-recursion.td Normal file
View File

@ -0,0 +1,9 @@
// RUN: not llvm-tblgen %s 2>&1 | FileCheck %s
// XFAIL: vg_leak
class A<string self> {
int x = !cast<A>(self).x;
}
// CHECK: error: Attempting to access field 'x' of 'A0' is a forbidden self-reference
def A0 : A<"A0">;