From 0413db4a26b0a1577b75c2979b0eb21f3490d17a Mon Sep 17 00:00:00 2001
From: Argyrios Kyrtzidis <akyrtzi@gmail.com>
Date: Mon, 31 Jan 2011 07:04:29 +0000
Subject: [PATCH] Amazing that there are still issues with the fields of
anonymous struct/unions.. Allow taking the address of such a field for a
pointer-to-member constant. Fixes rdar://8818236.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@124575 91177308-0d34-0410-b5e6-96231b3b80d8
---
include/clang/Sema/Sema.h | 1 +
lib/CodeGen/ItaniumCXXABI.cpp | 34 ++++++++++++++++---
lib/Sema/SemaExpr.cpp | 30 +++++++++++-----
.../anonymous-union-member-initializer.cpp | 14 ++++++++
4 files changed, 65 insertions(+), 14 deletions(-)
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index 781e3588ee0..d3b43c45095 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -1784,6 +1784,7 @@ public:
const CXXScopeSpec *SS = 0);
ExprResult
BuildAnonymousStructUnionMemberReference(SourceLocation Loc,
+ const CXXScopeSpec &SS,
IndirectFieldDecl *IndirectField,
Expr *BaseObjectExpr = 0,
SourceLocation OpLoc = SourceLocation());
diff --git a/lib/CodeGen/ItaniumCXXABI.cpp b/lib/CodeGen/ItaniumCXXABI.cpp
index ef5455c2869..8a7ac0a83a4 100644
--- a/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/lib/CodeGen/ItaniumCXXABI.cpp
@@ -493,17 +493,41 @@ ItaniumCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) {
/*Packed=*/false);
}
+static uint64_t getFieldOffset(const FieldDecl *FD, CodeGenModule &CGM) {
+ const CGRecordLayout &RL = CGM.getTypes().getCGRecordLayout(FD->getParent());
+ const llvm::StructType *ClassLTy = RL.getLLVMType();
+
+ unsigned FieldNo = RL.getLLVMFieldNo(FD);
+ return
+ CGM.getTargetData().getStructLayout(ClassLTy)->getElementOffset(FieldNo);
+}
+
llvm::Constant *ItaniumCXXABI::EmitMemberPointer(const FieldDecl *FD) {
// Itanium C++ ABI 2.3:
// A pointer to data member is an offset from the base address of
// the class object containing it, represented as a ptrdiff_t
- const CGRecordLayout &RL = CGM.getTypes().getCGRecordLayout(FD->getParent());
- const llvm::StructType *ClassLTy = RL.getLLVMType();
+ const RecordDecl *parent = FD->getParent();
+ if (!parent->isAnonymousStructOrUnion())
+ return llvm::ConstantInt::get(getPtrDiffTy(), getFieldOffset(FD, CGM));
- unsigned FieldNo = RL.getLLVMFieldNo(FD);
- uint64_t Offset =
- CGM.getTargetData().getStructLayout(ClassLTy)->getElementOffset(FieldNo);
+ // Handle a field injected from an anonymous struct or union.
+
+ assert(FD->getDeclName() && "Requested pointer to member with no name!");
+
+ // Find the record which the field was injected into.
+ while (parent->isAnonymousStructOrUnion())
+ parent = cast<RecordDecl>(parent->getParent());
+
+ RecordDecl::lookup_const_result lookup = parent->lookup(FD->getDeclName());
+ assert(lookup.first != lookup.second && "Didn't find the field!");
+ const IndirectFieldDecl *indirectFD = cast<IndirectFieldDecl>(*lookup.first);
+
+ uint64_t Offset = 0;
+ for (IndirectFieldDecl::chain_iterator
+ I= indirectFD->chain_begin(), E= indirectFD->chain_end(); I!=E; ++I) {
+ Offset += getFieldOffset(cast<FieldDecl>(*I), CGM);
+ }
return llvm::ConstantInt::get(getPtrDiffTy(), Offset);
}
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 098f5396bb0..2429c75880e 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -853,6 +853,7 @@ BuildFieldReferenceExpr(Sema &S, Expr *BaseExpr, bool IsArrow,
ExprResult
Sema::BuildAnonymousStructUnionMemberReference(SourceLocation Loc,
+ const CXXScopeSpec &SS,
IndirectFieldDecl *IndirectField,
Expr *BaseObjectExpr,
SourceLocation OpLoc) {
@@ -911,9 +912,21 @@ Sema::BuildAnonymousStructUnionMemberReference(SourceLocation Loc,
BaseQuals = Qualifiers::fromCVRMask(MD->getTypeQualifiers());
}
- if (!BaseObjectExpr)
- return ExprError(Diag(Loc, diag::err_invalid_non_static_member_use)
- << IndirectField->getDeclName());
+ if (!BaseObjectExpr) {
+ // The field is referenced for a pointer-to-member expression, e.g:
+ //
+ // struct S {
+ // union {
+ // char c;
+ // };
+ // };
+ // char S::*foo = &S::c;
+ //
+ FieldDecl *field = IndirectField->getAnonField();
+ DeclarationNameInfo NameInfo(field->getDeclName(), Loc);
+ return BuildDeclRefExpr(field, field->getType().getNonReferenceType(),
+ VK_LValue, NameInfo, &SS);
+ }
}
// Build the implicit member references to the field of the
@@ -929,9 +942,6 @@ Sema::BuildAnonymousStructUnionMemberReference(SourceLocation Loc,
for (; FI != FEnd; FI++) {
FieldDecl *Field = cast<FieldDecl>(*FI);
- // FIXME: the first access can be qualified
- CXXScopeSpec SS;
-
// FIXME: these are somewhat meaningless
DeclarationNameInfo MemberNameInfo(Field->getDeclName(), Loc);
DeclAccessPair FoundDecl = DeclAccessPair::make(Field, Field->getAccess());
@@ -2035,7 +2045,7 @@ Sema::BuildImplicitMemberExpr(const CXXScopeSpec &SS,
// FIXME: This needs to happen post-isImplicitMemberReference?
// FIXME: template-ids inside anonymous structs?
if (IndirectFieldDecl *FD = R.getAsSingle<IndirectFieldDecl>())
- return BuildAnonymousStructUnionMemberReference(Loc, FD);
+ return BuildAnonymousStructUnionMemberReference(Loc, SS, FD);
// If this is known to be an instance access, go ahead and build a
@@ -2228,7 +2238,7 @@ Sema::BuildDeclarationNameExpr(const CXXScopeSpec &SS,
// Handle anonymous.
if (IndirectFieldDecl *FD = dyn_cast<IndirectFieldDecl>(VD))
- return BuildAnonymousStructUnionMemberReference(Loc, FD);
+ return BuildAnonymousStructUnionMemberReference(Loc, SS, FD);
ExprValueKind VK = getValueKindForDecl(Context, VD);
@@ -3400,7 +3410,7 @@ Sema::BuildMemberReferenceExpr(Expr *BaseExpr, QualType BaseExprType,
if (IndirectFieldDecl *FD = dyn_cast<IndirectFieldDecl>(MemberDecl))
// We may have found a field within an anonymous union or struct
// (C++ [class.union]).
- return BuildAnonymousStructUnionMemberReference(MemberLoc, FD,
+ return BuildAnonymousStructUnionMemberReference(MemberLoc, SS, FD,
BaseExpr, OpLoc);
if (VarDecl *Var = dyn_cast<VarDecl>(MemberDecl)) {
@@ -7346,6 +7356,8 @@ static QualType CheckAddressOfOperand(Sema &S, Expr *OrigOp,
return QualType();
}
+ while (cast<RecordDecl>(Ctx)->isAnonymousStructOrUnion())
+ Ctx = Ctx->getParent();
return S.Context.getMemberPointerType(op->getType(),
S.Context.getTypeDeclType(cast<RecordDecl>(Ctx)).getTypePtr());
}
diff --git a/test/CodeGenCXX/anonymous-union-member-initializer.cpp b/test/CodeGenCXX/anonymous-union-member-initializer.cpp
index 87d3fcc6c37..d97a2ae366b 100644
--- a/test/CodeGenCXX/anonymous-union-member-initializer.cpp
+++ b/test/CodeGenCXX/anonymous-union-member-initializer.cpp
@@ -1,5 +1,19 @@
// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -o - %s | FileCheck %s
+// rdar://8818236
+namespace rdar8818236 {
+struct S {
+ char c2;
+ union {
+ char c;
+ int i;
+ };
+};
+
+// CHECK: @_ZN11rdar88182363fooE = global i64 4
+char S::*foo = &S::c;
+}
+
struct A {
union {
int a;
--
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