[c++20] Implement P0428R2 - Familiar template syntax for generic lambdas

Differential Revision: https://reviews.llvm.org/D36527

llvm-svn: 359967

1 files changed, 23 insertions, 1 deletions

diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 3357756466f..1eb5460dd61 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -486,6 +486,7 @@ private:
                        const AbiTagList *AdditionalAbiTags);
   void mangleBlockForPrefix(const BlockDecl *Block);
   void mangleUnqualifiedBlock(const BlockDecl *Block);
+  void mangleTemplateParamDecl(const NamedDecl *Decl);
   void mangleLambda(const CXXRecordDecl *Lambda);
   void mangleNestedName(const NamedDecl *ND, const DeclContext *DC,
                         const AbiTagList *AdditionalAbiTags,
@@ -1372,7 +1373,8 @@ void CXXNameMangler::mangleUnqualifiedName(const NamedDecl *ND,
     // <unnamed-type-name> ::= <closure-type-name>
     //
     // <closure-type-name> ::= Ul <lambda-sig> E [ <nonnegative number> ] _
-    // <lambda-sig> ::= <parameter-type>+   # Parameter types or 'v' for 'void'.
+    // <lambda-sig> ::= <template-param-decl>* <parameter-type>+
+    //     # Parameter types or 'v' for 'void'.
     if (const CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(TD)) {
       if (Record->isLambda() && Record->getLambdaManglingNumber()) {
         assert(!AdditionalAbiTags &&
@@ -1678,6 +1680,24 @@ void CXXNameMangler::mangleUnqualifiedBlock(const BlockDecl *Block) {
   Out << '_';
 }
 
+// <template-param-decl>
+//   ::= Ty                              # template type parameter
+//   ::= Tn <type>                       # template non-type parameter
+//   ::= Tt <template-param-decl>* E     # template template parameter
+void CXXNameMangler::mangleTemplateParamDecl(const NamedDecl *Decl) {
+  if (isa<TemplateTypeParmDecl>(Decl)) {
+    Out << "Ty";
+  } else if (auto *Tn = dyn_cast<NonTypeTemplateParmDecl>(Decl)) {
+    Out << "Tn";
+    mangleType(Tn->getType());
+  } else if (auto *Tt = dyn_cast<TemplateTemplateParmDecl>(Decl)) {
+    Out << "Tt";
+    for (auto *Param : *Tt->getTemplateParameters())
+      mangleTemplateParamDecl(Param);
+    Out << "E";
+  }
+}
+
 void CXXNameMangler::mangleLambda(const CXXRecordDecl *Lambda) {
   // If the context of a closure type is an initializer for a class member
   // (static or nonstatic), it is encoded in a qualified name with a final
@@ -1705,6 +1725,8 @@ void CXXNameMangler::mangleLambda(const CXXRecordDecl *Lambda) {
   }
 
   Out << "Ul";
+  for (auto *D : Lambda->getLambdaExplicitTemplateParameters())
+    mangleTemplateParamDecl(D);
   const FunctionProtoType *Proto = Lambda->getLambdaTypeInfo()->getType()->
                                    getAs<FunctionProtoType>();
   mangleBareFunctionType(Proto, /*MangleReturnType=*/false,