Completely reimplement __builtin_offsetof, based on a patch by Roberto
Amadini.
This change introduces a new expression node type, OffsetOfExpr, that
describes __builtin_offsetof. Previously, __builtin_offsetof was
implemented using a unary operator whose subexpression involved
various synthesized array-subscript and member-reference expressions,
which was ugly and made it very hard to instantiate as a
template. OffsetOfExpr represents the AST more faithfully, with proper
type source information and a more compact representation.
OffsetOfExpr also has support for dependent __builtin_offsetof
expressions; it can be value-dependent, but will never be
type-dependent (like sizeof or alignof). This commit introduces
template instantiation for __builtin_offsetof as well.
There are two major caveats to this patch:
1) CodeGen cannot handle the case where __builtin_offsetof is not a
constant expression, so it produces an error. So, to avoid
regressing in C, we retain the old UnaryOperator-based
__builtin_offsetof implementation in C while using the shiny new
OffsetOfExpr implementation in C++. The old implementation can go
away once we have proper CodeGen support for this case, which we
expect won't cause much trouble in C++.
2) __builtin_offsetof doesn't work well with non-POD class types,
particularly when the designated field is found within a base
class. I will address this in a subsequent patch.
Fixes PR5880 and a bunch of assertions when building Boost.Python
tests.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@102542 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Checker/GRExprEngine.cpp b/lib/Checker/GRExprEngine.cpp
index c11a16f..67090b8 100644
--- a/lib/Checker/GRExprEngine.cpp
+++ b/lib/Checker/GRExprEngine.cpp
@@ -823,6 +823,10 @@
VisitReturnStmt(cast<ReturnStmt>(S), Pred, Dst);
break;
+ case Stmt::OffsetOfExprClass:
+ VisitOffsetOfExpr(cast<OffsetOfExpr>(S), Pred, Dst);
+ break;
+
case Stmt::SizeOfAlignOfExprClass:
VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), Pred, Dst);
break;
@@ -2611,6 +2615,21 @@
ValMgr.makeIntVal(amt.getQuantity(), Ex->getType())));
}
+void GRExprEngine::VisitOffsetOfExpr(OffsetOfExpr* OOE, ExplodedNode* Pred,
+ ExplodedNodeSet& Dst) {
+ Expr::EvalResult Res;
+ if (OOE->Evaluate(Res, getContext()) && Res.Val.isInt()) {
+ const APSInt &IV = Res.Val.getInt();
+ assert(IV.getBitWidth() == getContext().getTypeSize(OOE->getType()));
+ assert(OOE->getType()->isIntegerType());
+ assert(IV.isSigned() == OOE->getType()->isSignedIntegerType());
+ SVal X = ValMgr.makeIntVal(IV);
+ MakeNode(Dst, OOE, Pred, GetState(Pred)->BindExpr(OOE, X));
+ return;
+ }
+ // FIXME: Handle the case where __builtin_offsetof is not a constant.
+ Dst.Add(Pred);
+}
void GRExprEngine::VisitUnaryOperator(UnaryOperator* U, ExplodedNode* Pred,
ExplodedNodeSet& Dst, bool asLValue) {
@@ -2692,19 +2711,19 @@
case UnaryOperator::OffsetOf: {
Expr::EvalResult Res;
if (U->Evaluate(Res, getContext()) && Res.Val.isInt()) {
- const APSInt &IV = Res.Val.getInt();
- assert(IV.getBitWidth() == getContext().getTypeSize(U->getType()));
- assert(U->getType()->isIntegerType());
- assert(IV.isSigned() == U->getType()->isSignedIntegerType());
- SVal X = ValMgr.makeIntVal(IV);
- MakeNode(Dst, U, Pred, GetState(Pred)->BindExpr(U, X));
- return;
- }
+ const APSInt &IV = Res.Val.getInt();
+ assert(IV.getBitWidth() == getContext().getTypeSize(U->getType()));
+ assert(U->getType()->isIntegerType());
+ assert(IV.isSigned() == U->getType()->isSignedIntegerType());
+ SVal X = ValMgr.makeIntVal(IV);
+ MakeNode(Dst, U, Pred, GetState(Pred)->BindExpr(U, X));
+ return;
+ }
// FIXME: Handle the case where __builtin_offsetof is not a constant.
Dst.Add(Pred);
return;
}
-
+
case UnaryOperator::Plus: assert (!asLValue); // FALL-THROUGH.
case UnaryOperator::Extension: {