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/Frontend/PCHWriterStmt.cpp b/lib/Frontend/PCHWriterStmt.cpp
index a0ea5c9..3d158a4 100644
--- a/lib/Frontend/PCHWriterStmt.cpp
+++ b/lib/Frontend/PCHWriterStmt.cpp
@@ -62,6 +62,7 @@
void VisitCharacterLiteral(CharacterLiteral *E);
void VisitParenExpr(ParenExpr *E);
void VisitUnaryOperator(UnaryOperator *E);
+ void VisitOffsetOfExpr(OffsetOfExpr *E);
void VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E);
void VisitArraySubscriptExpr(ArraySubscriptExpr *E);
void VisitCallExpr(CallExpr *E);
@@ -393,6 +394,37 @@
Code = pch::EXPR_UNARY_OPERATOR;
}
+void PCHStmtWriter::VisitOffsetOfExpr(OffsetOfExpr *E) {
+ VisitExpr(E);
+ Record.push_back(E->getNumComponents());
+ Record.push_back(E->getNumExpressions());
+ Writer.AddSourceLocation(E->getOperatorLoc(), Record);
+ Writer.AddSourceLocation(E->getRParenLoc(), Record);
+ Writer.AddTypeSourceInfo(E->getTypeSourceInfo(), Record);
+ for (unsigned I = 0, N = E->getNumComponents(); I != N; ++I) {
+ const OffsetOfExpr::OffsetOfNode &ON = E->getComponent(I);
+ Record.push_back(ON.getKind()); // FIXME: Stable encoding
+ Writer.AddSourceLocation(ON.getRange().getBegin(), Record);
+ Writer.AddSourceLocation(ON.getRange().getEnd(), Record);
+ switch (ON.getKind()) {
+ case OffsetOfExpr::OffsetOfNode::Array:
+ Record.push_back(ON.getArrayExprIndex());
+ break;
+
+ case OffsetOfExpr::OffsetOfNode::Field:
+ Writer.AddDeclRef(ON.getField(), Record);
+ break;
+
+ case OffsetOfExpr::OffsetOfNode::Identifier:
+ Writer.AddIdentifierRef(ON.getFieldName(), Record);
+ break;
+ }
+ }
+ for (unsigned I = 0, N = E->getNumExpressions(); I != N; ++I)
+ Writer.WriteSubStmt(E->getIndexExpr(I));
+ Code = pch::EXPR_OFFSETOF;
+}
+
void PCHStmtWriter::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E) {
VisitExpr(E);
Record.push_back(E->isSizeOf());