Improve name mangling for instantiation-dependent types that are not
dependent. This covers an odd class of types such as
int (&)[sizeof(sizeof(T() + T()))];
which involve template parameters but, because of some trick typically
involving a form of expression that is never type-dependent, resolve
down to a non-dependent type. Such types need to be mangled
essentially as they were written in the source code (involving
template parameters), rather than via their canonical type.
In general, instantiation-dependent types should be mangled as
they were written in the source. However, since we can't do that now
without non-trivial refactoring of the AST (see the new FIXME), I've
gone for this partial solution: only use the as-written-in-the-source
mangling for these strange types that are instantiation-dependent but
not dependent. This provides better compatibility with previous
incarnations of Clang and with GCC. In the future, we'd like to get
this right.
Fixes <rdar://problem/9663282>.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134984 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ItaniumMangle.cpp b/lib/AST/ItaniumMangle.cpp
index 5b247f2..b07e962 100644
--- a/lib/AST/ItaniumMangle.cpp
+++ b/lib/AST/ItaniumMangle.cpp
@@ -319,7 +319,7 @@
unsigned NumTemplateArgs);
void mangleTemplateArgs(const TemplateParameterList &PL,
const TemplateArgumentList &AL);
- void mangleTemplateArg(const NamedDecl *P, const TemplateArgument &A);
+ void mangleTemplateArg(const NamedDecl *P, TemplateArgument A);
void mangleUnresolvedTemplateArgs(const TemplateArgument *args,
unsigned numArgs);
@@ -1596,26 +1596,59 @@
Context.mangleObjCMethodName(MD, Out);
}
-void CXXNameMangler::mangleType(QualType nonCanon) {
- // Only operate on the canonical type!
- QualType canon = nonCanon.getCanonicalType();
+void CXXNameMangler::mangleType(QualType T) {
+ // If our type is instantiation-dependent but not dependent, we mangle
+ // it as it was written in the source, removing any top-level sugar.
+ // Otherwise, use the canonical type.
+ //
+ // FIXME: This is an approximation of the instantiation-dependent name
+ // mangling rules, since we should really be using the type as written and
+ // augmented via semantic analysis (i.e., with implicit conversions and
+ // default template arguments) for any instantiation-dependent type.
+ // Unfortunately, that requires several changes to our AST:
+ // - Instantiation-dependent TemplateSpecializationTypes will need to be
+ // uniqued, so that we can handle substitutions properly
+ // - Default template arguments will need to be represented in the
+ // TemplateSpecializationType, since they need to be mangled even though
+ // they aren't written.
+ // - Conversions on non-type template arguments need to be expressed, since
+ // they can affect the mangling of sizeof/alignof.
+ if (!T->isInstantiationDependentType() || T->isDependentType())
+ T = T.getCanonicalType();
+ else {
+ // Desugar any types that are purely sugar.
+ do {
+ // Don't desugar through template specialization types that aren't
+ // type aliases. We need to mangle the template arguments as written.
+ if (const TemplateSpecializationType *TST
+ = dyn_cast<TemplateSpecializationType>(T))
+ if (!TST->isTypeAlias())
+ break;
- SplitQualType split = canon.split();
+ QualType Desugared
+ = T.getSingleStepDesugaredType(Context.getASTContext());
+ if (Desugared == T)
+ break;
+
+ T = Desugared;
+ } while (true);
+ }
+ SplitQualType split = T.split();
Qualifiers quals = split.second;
const Type *ty = split.first;
- bool isSubstitutable = quals || !isa<BuiltinType>(ty);
- if (isSubstitutable && mangleSubstitution(canon))
+ bool isSubstitutable = quals || !isa<BuiltinType>(T);
+ if (isSubstitutable && mangleSubstitution(T))
return;
// If we're mangling a qualified array type, push the qualifiers to
// the element type.
- if (quals && isa<ArrayType>(ty)) {
- ty = Context.getASTContext().getAsArrayType(canon);
+ if (quals && isa<ArrayType>(T)) {
+ ty = Context.getASTContext().getAsArrayType(T);
quals = Qualifiers();
- // Note that we don't update canon: we want to add the
- // substitution at the canonical type.
+ // Note that we don't update T: we want to add the
+ // substitution at the original type.
}
if (quals) {
@@ -1640,7 +1673,7 @@
// Add the substitution.
if (isSubstitutable)
- addSubstitution(canon);
+ addSubstitution(T);
}
void CXXNameMangler::mangleNameOrStandardSubstitution(const NamedDecl *ND) {
@@ -2826,12 +2859,15 @@
}
void CXXNameMangler::mangleTemplateArg(const NamedDecl *P,
- const TemplateArgument &A) {
+ TemplateArgument A) {
// <template-arg> ::= <type> # type or template
// ::= X <expression> E # expression
// ::= <expr-primary> # simple expressions
// ::= J <template-arg>* E # argument pack
- // ::= sp <expression> # pack expansion of (C++0x)
+ // ::= sp <expression> # pack expansion of (C++0x)
+ if (!A.isInstantiationDependent() || A.isDependent())
+ A = Context.getASTContext().getCanonicalTemplateArgument(A);
+
switch (A.getKind()) {
case TemplateArgument::Null:
llvm_unreachable("Cannot mangle NULL template argument");
diff --git a/lib/AST/Type.cpp b/lib/AST/Type.cpp
index 89c00eb..1f0a37e 100644
--- a/lib/AST/Type.cpp
+++ b/lib/AST/Type.cpp
@@ -180,6 +180,26 @@
return Context.getQualifiedType(split.first, split.second);
}
+QualType QualType::getSingleStepDesugaredType(const ASTContext &Context) const {
+ QualifierCollector Qs;
+
+ const Type *CurTy = Qs.strip(*this);
+ switch (CurTy->getTypeClass()) {
+#define ABSTRACT_TYPE(Class, Parent)
+#define TYPE(Class, Parent) \
+ case Type::Class: { \
+ const Class##Type *Ty = cast<Class##Type>(CurTy); \
+ if (!Ty->isSugared()) \
+ return *this; \
+ return Context.getQualifiedType(Ty->desugar(), Qs); \
+ break; \
+ }
+#include "clang/AST/TypeNodes.def"
+ }
+
+ return *this;
+}
+
SplitQualType QualType::getSplitDesugaredType(QualType T) {
QualifierCollector Qs;