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/AST/StmtProfile.cpp b/lib/AST/StmtProfile.cpp
index 3a19ec2..3d528f3 100644
--- a/lib/AST/StmtProfile.cpp
+++ b/lib/AST/StmtProfile.cpp
@@ -261,6 +261,30 @@
ID.AddInteger(S->getOpcode());
}
+void StmtProfiler::VisitOffsetOfExpr(OffsetOfExpr *S) {
+ VisitType(S->getTypeSourceInfo()->getType());
+ unsigned n = S->getNumComponents();
+ for (unsigned i = 0; i < n; ++i) {
+ const OffsetOfExpr::OffsetOfNode& ON = S->getComponent(i);
+ ID.AddInteger(ON.getKind());
+ switch (ON.getKind()) {
+ case OffsetOfExpr::OffsetOfNode::Array:
+ // Expressions handled below.
+ break;
+
+ case OffsetOfExpr::OffsetOfNode::Field:
+ VisitDecl(ON.getField());
+ break;
+
+ case OffsetOfExpr::OffsetOfNode::Identifier:
+ ID.AddPointer(ON.getFieldName());
+ break;
+ }
+ }
+
+ VisitExpr(S);
+}
+
void StmtProfiler::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *S) {
VisitExpr(S);
ID.AddBoolean(S->isSizeOf());