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/StmtXML.cpp b/lib/Frontend/StmtXML.cpp
index ce474d3..21dc0ba 100644
--- a/lib/Frontend/StmtXML.cpp
+++ b/lib/Frontend/StmtXML.cpp
@@ -125,6 +125,7 @@
void VisitFloatingLiteral(FloatingLiteral *Node);
void VisitStringLiteral(StringLiteral *Str);
void VisitUnaryOperator(UnaryOperator *Node);
+ void VisitOffsetOfExpr(OffsetOfExpr *Node);
void VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *Node);
void VisitMemberExpr(MemberExpr *Node);
void VisitExtVectorElementExpr(ExtVectorElementExpr *Node);
@@ -308,6 +309,10 @@
Doc.addAttribute("op_code", getOpcodeStr(Node->getOpcode()));
}
+void StmtXML::OffsetOfExpr(OffsetOfExpr *Node) {
+ DumpExpr(Node);
+}
+
void StmtXML::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *Node) {
DumpExpr(Node);
Doc.addAttribute("is_sizeof", Node->isSizeOf() ? "sizeof" : "alignof");