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/StmtPrinter.cpp b/lib/AST/StmtPrinter.cpp
index 3996528..b50bb0c 100644
--- a/lib/AST/StmtPrinter.cpp
+++ b/lib/AST/StmtPrinter.cpp
@@ -17,6 +17,7 @@
#include "clang/AST/DeclObjC.h"
#include "clang/AST/PrettyPrinter.h"
#include "llvm/Support/Format.h"
+#include "clang/AST/Expr.h"
using namespace clang;
//===----------------------------------------------------------------------===//
@@ -703,6 +704,35 @@
OS << ")";
}
+void StmtPrinter::VisitOffsetOfExpr(OffsetOfExpr *Node) {
+ OS << "__builtin_offsetof(";
+ OS << Node->getTypeSourceInfo()->getType().getAsString() << ", ";
+ bool PrintedSomething = false;
+ for (unsigned i = 0, n = Node->getNumComponents(); i < n; ++i) {
+ OffsetOfExpr::OffsetOfNode ON = Node->getComponent(i);
+ if (ON.getKind() == OffsetOfExpr::OffsetOfNode::Array) {
+ // Array node
+ OS << "[";
+ PrintExpr(Node->getIndexExpr(ON.getArrayExprIndex()));
+ OS << "]";
+ PrintedSomething = true;
+ continue;
+ }
+
+ // Field or identifier node.
+ IdentifierInfo *Id = ON.getFieldName();
+ if (!Id)
+ continue;
+
+ if (PrintedSomething)
+ OS << ".";
+ else
+ PrintedSomething = true;
+ OS << Id->getName();
+ }
+ OS << ")";
+}
+
void StmtPrinter::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *Node) {
OS << (Node->isSizeOf() ? "sizeof" : "__alignof");
if (Node->isArgumentType())