From 882211c1da17254908e6b36d6e5d4e425f224347 Mon Sep 17 00:00:00 2001 From: Douglas Gregor Date: Wed, 28 Apr 2010 22:16:22 +0000 Subject: 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. llvm-svn: 102542 --- clang/lib/Frontend/PCHWriterStmt.cpp | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) (limited to 'clang/lib/Frontend/PCHWriterStmt.cpp') diff --git a/clang/lib/Frontend/PCHWriterStmt.cpp b/clang/lib/Frontend/PCHWriterStmt.cpp index a0ea5c9553c..3d158a48dec 100644 --- a/clang/lib/Frontend/PCHWriterStmt.cpp +++ b/clang/lib/Frontend/PCHWriterStmt.cpp @@ -62,6 +62,7 @@ namespace { 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 @@ void PCHStmtWriter::VisitUnaryOperator(UnaryOperator *E) { 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()); -- cgit v1.2.3