r224131 - Fix the issue of mangling of local anonymous unions (Itanium C++ ABI):
Evgeny Astigeevich
evgeny.astigeevich at arm.com
Fri Dec 12 08:17:47 PST 2014
Author: eastig
Date: Fri Dec 12 10:17:46 2014
New Revision: 224131
URL: http://llvm.org/viewvc/llvm-project?rev=224131&view=rev
Log:
Fix the issue of mangling of local anonymous unions (Itanium C++ ABI):
A discriminator is used for the first occurrence of a name.
inline int f1 () {
static union {
int a;
long int b;
};
static union {
int c;
double d;
};
return a+c;
}
The name of the second union is mangled as _ZZ2f1vE1c_0 instead of _ZZ2f1vE1c.
Differential Revision: http://reviews.llvm.org/D6295
Added:
cfe/trunk/test/CodeGenCXX/mangle-local-anonymous-unions.cpp
Modified:
cfe/trunk/include/clang/AST/Decl.h
cfe/trunk/lib/AST/Decl.cpp
cfe/trunk/lib/AST/ItaniumCXXABI.cpp
cfe/trunk/lib/AST/ItaniumMangle.cpp
Modified: cfe/trunk/include/clang/AST/Decl.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Decl.h?rev=224131&r1=224130&r2=224131&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/Decl.h (original)
+++ cfe/trunk/include/clang/AST/Decl.h Fri Dec 12 10:17:46 2014
@@ -3274,6 +3274,10 @@ public:
/// intra-object-overflow bugs.
bool mayInsertExtraPadding(bool EmitRemark = false) const;
+ /// Finds the first data member which has a name.
+ /// nullptr is returned if no named data member exists.
+ const FieldDecl *findFirstNamedDataMember() const;
+
private:
/// \brief Deserialize just the fields.
void LoadFieldsFromExternalStorage() const;
Modified: cfe/trunk/lib/AST/Decl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Decl.cpp?rev=224131&r1=224130&r2=224131&view=diff
==============================================================================
--- cfe/trunk/lib/AST/Decl.cpp (original)
+++ cfe/trunk/lib/AST/Decl.cpp Fri Dec 12 10:17:46 2014
@@ -3670,6 +3670,22 @@ bool RecordDecl::mayInsertExtraPadding(b
return ReasonToReject < 0;
}
+const FieldDecl *RecordDecl::findFirstNamedDataMember() const {
+ for (const auto *I : fields()) {
+ if (I->getIdentifier())
+ return I;
+
+ if (const RecordType *RT = I->getType()->getAs<RecordType>())
+ if (const FieldDecl *NamedDataMember =
+ RT->getDecl()->findFirstNamedDataMember())
+ return NamedDataMember;
+ }
+
+ // We didn't find a named data member.
+ return nullptr;
+}
+
+
//===----------------------------------------------------------------------===//
// BlockDecl Implementation
//===----------------------------------------------------------------------===//
Modified: cfe/trunk/lib/AST/ItaniumCXXABI.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ItaniumCXXABI.cpp?rev=224131&r1=224130&r2=224131&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ItaniumCXXABI.cpp (original)
+++ cfe/trunk/lib/AST/ItaniumCXXABI.cpp Fri Dec 12 10:17:46 2014
@@ -29,12 +29,33 @@ using namespace clang;
namespace {
+/// According to Itanium C++ ABI 5.1.2:
+/// the name of an anonymous union is considered to be
+/// the name of the first named data member found by a pre-order,
+/// depth-first, declaration-order walk of the data members of
+/// the anonymous union.
+/// If there is no such data member (i.e., if all of the data members
+/// in the union are unnamed), then there is no way for a program to
+/// refer to the anonymous union, and there is therefore no need to mangle its name.
+///
+/// Returns the name of anonymous union VarDecl or nullptr if it is not found.
+static const IdentifierInfo *findAnonymousUnionVarDeclName(const VarDecl& VD) {
+ const RecordType *RT = VD.getType()->getAs<RecordType>();
+ assert(RT && "type of VarDecl is expected to be RecordType.");
+ assert(RT->getDecl()->isUnion() && "RecordType is expected to be a union.");
+ if (const FieldDecl *FD = RT->getDecl()->findFirstNamedDataMember()) {
+ return FD->getIdentifier();
+ }
+
+ return nullptr;
+}
+
/// \brief Keeps track of the mangled names of lambda expressions and block
/// literals within a particular context.
class ItaniumNumberingContext : public MangleNumberingContext {
llvm::DenseMap<const Type *, unsigned> ManglingNumbers;
- llvm::DenseMap<IdentifierInfo *, unsigned> VarManglingNumbers;
- llvm::DenseMap<IdentifierInfo *, unsigned> TagManglingNumbers;
+ llvm::DenseMap<const IdentifierInfo *, unsigned> VarManglingNumbers;
+ llvm::DenseMap<const IdentifierInfo *, unsigned> TagManglingNumbers;
public:
unsigned getManglingNumber(const CXXMethodDecl *CallOperator) override {
@@ -60,7 +81,12 @@ public:
/// Variable decls are numbered by identifier.
unsigned getManglingNumber(const VarDecl *VD, unsigned) override {
- return ++VarManglingNumbers[VD->getIdentifier()];
+ const IdentifierInfo *Identifier = VD->getIdentifier();
+ if (!Identifier) {
+ // VarDecl without an identifier represents an anonymous union declaration.
+ Identifier = findAnonymousUnionVarDeclName(*VD);
+ }
+ return ++VarManglingNumbers[Identifier];
}
unsigned getManglingNumber(const TagDecl *TD, unsigned) override {
Modified: cfe/trunk/lib/AST/ItaniumMangle.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ItaniumMangle.cpp?rev=224131&r1=224130&r2=224131&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ItaniumMangle.cpp (original)
+++ cfe/trunk/lib/AST/ItaniumMangle.cpp Fri Dec 12 10:17:46 2014
@@ -117,7 +117,7 @@ class ItaniumMangleContextImpl : public
typedef std::pair<const DeclContext*, IdentifierInfo*> DiscriminatorKeyTy;
llvm::DenseMap<DiscriminatorKeyTy, unsigned> Discriminator;
llvm::DenseMap<const NamedDecl*, unsigned> Uniquifier;
-
+
public:
explicit ItaniumMangleContextImpl(ASTContext &Context,
DiagnosticsEngine &Diags)
@@ -1050,24 +1050,6 @@ void CXXNameMangler::mangleUnresolvedNam
mangleUnqualifiedName(nullptr, name, knownArity);
}
-static const FieldDecl *FindFirstNamedDataMember(const RecordDecl *RD) {
- assert(RD->isAnonymousStructOrUnion() &&
- "Expected anonymous struct or union!");
-
- for (const auto *I : RD->fields()) {
- if (I->getIdentifier())
- return I;
-
- if (const RecordType *RT = I->getType()->getAs<RecordType>())
- if (const FieldDecl *NamedDataMember =
- FindFirstNamedDataMember(RT->getDecl()))
- return NamedDataMember;
- }
-
- // We didn't find a named data member.
- return nullptr;
-}
-
void CXXNameMangler::mangleUnqualifiedName(const NamedDecl *ND,
DeclarationName Name,
unsigned KnownArity) {
@@ -1104,9 +1086,9 @@ void CXXNameMangler::mangleUnqualifiedNa
if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
// We must have an anonymous union or struct declaration.
- const RecordDecl *RD =
+ const RecordDecl *RD =
cast<RecordDecl>(VD->getType()->getAs<RecordType>()->getDecl());
-
+
// Itanium C++ ABI 5.1.2:
//
// For the purposes of mangling, the name of an anonymous union is
@@ -1116,14 +1098,16 @@ void CXXNameMangler::mangleUnqualifiedNa
// the data members in the union are unnamed), then there is no way for
// a program to refer to the anonymous union, and there is therefore no
// need to mangle its name.
- const FieldDecl *FD = FindFirstNamedDataMember(RD);
+ assert(RD->isAnonymousStructOrUnion()
+ && "Expected anonymous struct or union!");
+ const FieldDecl *FD = RD->findFirstNamedDataMember();
// It's actually possible for various reasons for us to get here
// with an empty anonymous struct / union. Fortunately, it
// doesn't really matter what name we generate.
if (!FD) break;
assert(FD->getIdentifier() && "Data member name isn't an identifier!");
-
+
mangleSourceName(FD->getIdentifier());
break;
}
@@ -3758,7 +3742,7 @@ void ItaniumMangleContextImpl::mangleCXX
"Mangling declaration");
CXXNameMangler Mangler(*this, Out, D);
- return Mangler.mangle(D);
+ Mangler.mangle(D);
}
void ItaniumMangleContextImpl::mangleCXXCtor(const CXXConstructorDecl *D,
@@ -3947,3 +3931,4 @@ ItaniumMangleContext *
ItaniumMangleContext::create(ASTContext &Context, DiagnosticsEngine &Diags) {
return new ItaniumMangleContextImpl(Context, Diags);
}
+
Added: cfe/trunk/test/CodeGenCXX/mangle-local-anonymous-unions.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/mangle-local-anonymous-unions.cpp?rev=224131&view=auto
==============================================================================
--- cfe/trunk/test/CodeGenCXX/mangle-local-anonymous-unions.cpp (added)
+++ cfe/trunk/test/CodeGenCXX/mangle-local-anonymous-unions.cpp Fri Dec 12 10:17:46 2014
@@ -0,0 +1,42 @@
+// RUN: %clang_cc1 %s -emit-llvm -triple %itanium_abi_triple -o - | FileCheck %s
+
+// CHECK-DAG: @_ZZ2f0vE1a
+// CHECK-DAG: @_ZZ2f0vE1c
+// CHECK-DAG: @_ZZ2f0vE1e_0
+inline int f0() {
+ static union {
+ int a;
+ long int b;
+ };
+
+ static union {
+ int c;
+ double d;
+ };
+
+ if (0) {
+ static union {
+ int e;
+ int f;
+ };
+ }
+ static union {
+ int e;
+ int f;
+ };
+
+ return a+c;
+}
+
+inline void nop() {
+ static union {
+ union {
+ };
+ };
+}
+
+int f1 (int a, int c) {
+ nop();
+ return a+c+f0();
+}
+
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