Revert "[Clang] Unify interface for accessing template arguments as written for class/variable template specializations (llvm#81642)"

This reverts commit 7115ed0.

This commit broke several LLDB tests.

https://green.lab.llvm.org/job/llvm.org/view/LLDB/job/as-lldb-cmake/3480/

Author: adrian-prantl

clang-tools-extra/clangd/AST.cpp

@@ -50,12 +50,17 @@ getTemplateSpecializationArgLocs(const NamedDecl &ND) {
     if (const ASTTemplateArgumentListInfo *Args =
             Func->getTemplateSpecializationArgsAsWritten())
       return Args->arguments();
-  } else if (auto *Cls = llvm::dyn_cast<ClassTemplateSpecializationDecl>(&ND)) {
+  } else if (auto *Cls =
+                 llvm::dyn_cast<ClassTemplatePartialSpecializationDecl>(&ND)) {
     if (auto *Args = Cls->getTemplateArgsAsWritten())
       return Args->arguments();
-  } else if (auto *Var = llvm::dyn_cast<VarTemplateSpecializationDecl>(&ND)) {
+  } else if (auto *Var =
+                 llvm::dyn_cast<VarTemplatePartialSpecializationDecl>(&ND)) {
     if (auto *Args = Var->getTemplateArgsAsWritten())
       return Args->arguments();
+  } else if (auto *Var = llvm::dyn_cast<VarTemplateSpecializationDecl>(&ND)) {
+    if (auto *Args = Var->getTemplateArgsInfo())
+      return Args->arguments();
   }
   // We return std::nullopt for ClassTemplateSpecializationDecls because it does
   // not contain TemplateArgumentLoc information.
@@ -265,10 +270,22 @@ std::string printTemplateSpecializationArgs(const NamedDecl &ND) {
           getTemplateSpecializationArgLocs(ND)) {
     printTemplateArgumentList(OS, *Args, Policy);
   } else if (auto *Cls = llvm::dyn_cast<ClassTemplateSpecializationDecl>(&ND)) {
-    // FIXME: Fix cases when getTypeAsWritten returns null inside clang AST,
-    // e.g. friend decls. Currently we fallback to Template Arguments without
-    // location information.
-    printTemplateArgumentList(OS, Cls->getTemplateArgs().asArray(), Policy);
+    if (const TypeSourceInfo *TSI = Cls->getTypeAsWritten()) {
+      // ClassTemplateSpecializationDecls do not contain
+      // TemplateArgumentTypeLocs, they only have TemplateArgumentTypes. So we
+      // create a new argument location list from TypeSourceInfo.
+      auto STL = TSI->getTypeLoc().getAs<TemplateSpecializationTypeLoc>();
+      llvm::SmallVector<TemplateArgumentLoc> ArgLocs;
+      ArgLocs.reserve(STL.getNumArgs());
+      for (unsigned I = 0; I < STL.getNumArgs(); ++I)
+        ArgLocs.push_back(STL.getArgLoc(I));
+      printTemplateArgumentList(OS, ArgLocs, Policy);
+    } else {
+      // FIXME: Fix cases when getTypeAsWritten returns null inside clang AST,
+      // e.g. friend decls. Currently we fallback to Template Arguments without
+      // location information.
+      printTemplateArgumentList(OS, Cls->getTemplateArgs().asArray(), Policy);
+    }
   }
   OS.flush();
   return TemplateArgs;
@@ -436,12 +453,10 @@ bool hasReservedScope(const DeclContext &DC) {
 }
 
 QualType declaredType(const TypeDecl *D) {
-  ASTContext &Context = D->getASTContext();
   if (const auto *CTSD = llvm::dyn_cast<ClassTemplateSpecializationDecl>(D))
-    if (const auto *Args = CTSD->getTemplateArgsAsWritten())
-      return Context.getTemplateSpecializationType(
-          TemplateName(CTSD->getSpecializedTemplate()), Args->arguments());
-  return Context.getTypeDeclType(D);
+    if (const auto *TSI = CTSD->getTypeAsWritten())
+      return TSI->getType();
+  return D->getASTContext().getTypeDeclType(D);
 }
 
 namespace {

clang-tools-extra/clangd/SemanticHighlighting.cpp

@@ -693,22 +693,17 @@ class CollectExtraHighlightings
     return true;
   }
 
-  bool
-  VisitClassTemplateSpecializationDecl(ClassTemplateSpecializationDecl *D) {
-    if (auto *Args = D->getTemplateArgsAsWritten())
-      H.addAngleBracketTokens(Args->getLAngleLoc(), Args->getRAngleLoc());
-    return true;
-  }
-
   bool VisitClassTemplatePartialSpecializationDecl(
       ClassTemplatePartialSpecializationDecl *D) {
     if (auto *TPL = D->getTemplateParameters())
       H.addAngleBracketTokens(TPL->getLAngleLoc(), TPL->getRAngleLoc());
+    if (auto *Args = D->getTemplateArgsAsWritten())
+      H.addAngleBracketTokens(Args->getLAngleLoc(), Args->getRAngleLoc());
     return true;
   }
 
   bool VisitVarTemplateSpecializationDecl(VarTemplateSpecializationDecl *D) {
-    if (auto *Args = D->getTemplateArgsAsWritten())
+    if (auto *Args = D->getTemplateArgsInfo())
       H.addAngleBracketTokens(Args->getLAngleLoc(), Args->getRAngleLoc());
     return true;
   }
@@ -717,6 +712,8 @@ class CollectExtraHighlightings
       VarTemplatePartialSpecializationDecl *D) {
     if (auto *TPL = D->getTemplateParameters())
       H.addAngleBracketTokens(TPL->getLAngleLoc(), TPL->getRAngleLoc());
+    if (auto *Args = D->getTemplateArgsAsWritten())
+      H.addAngleBracketTokens(Args->getLAngleLoc(), Args->getRAngleLoc());
     return true;
   }
 

clang-tools-extra/include-cleaner/lib/WalkAST.cpp

@@ -267,21 +267,18 @@ class ASTWalker : public RecursiveASTVisitor<ASTWalker> {
     return true;
   }
 
-  // Report a reference from explicit specializations/instantiations to the
-  // specialized template. Implicit ones are filtered out by RAV.
+  // Report a reference from explicit specializations to the specialized
+  // template. Implicit ones are filtered out by RAV and explicit instantiations
+  // are already traversed through typelocs.
   bool
   VisitClassTemplateSpecializationDecl(ClassTemplateSpecializationDecl *CTSD) {
-    // if (CTSD->isExplicitSpecialization())
-    if (clang::isTemplateExplicitInstantiationOrSpecialization(
-            CTSD->getTemplateSpecializationKind()))
+    if (CTSD->isExplicitSpecialization())
       report(CTSD->getLocation(),
              CTSD->getSpecializedTemplate()->getTemplatedDecl());
     return true;
   }
   bool VisitVarTemplateSpecializationDecl(VarTemplateSpecializationDecl *VTSD) {
-    // if (VTSD->isExplicitSpecialization())
-    if (clang::isTemplateExplicitInstantiationOrSpecialization(
-            VTSD->getTemplateSpecializationKind()))
+    if (VTSD->isExplicitSpecialization())
       report(VTSD->getLocation(),
              VTSD->getSpecializedTemplate()->getTemplatedDecl());
     return true;