Merge branch 'release/20.x' into Backport_AVX10

Author: tstellar

.github/workflows/libclang-abi-tests.yml

@@ -103,6 +103,7 @@ jobs:
         uses: llvm/actions/install-ninja@main
       - name: Install abi-compliance-checker
         run: |
+          sudo apt-get update
           sudo apt-get install abi-dumper autoconf pkg-config
       - name: Install universal-ctags
         run: |
@@ -154,7 +155,9 @@ jobs:
           path: build-latest
 
       - name: Install abi-compliance-checker
-        run: sudo apt-get install abi-compliance-checker
+        run: |
+          sudo apt-get update
+          sudo apt-get install abi-compliance-checker
       - name: Compare ABI
         run: |
           for lib in ${{ needs.abi-dump-setup.outputs.ABI_LIBS }}; do

.github/workflows/llvm-tests.yml

@@ -91,6 +91,7 @@ jobs:
         uses: llvm/actions/install-ninja@main
       - name: Install abi-compliance-checker
         run: |
+          sudo apt-get update
           sudo apt-get install abi-dumper autoconf pkg-config
       - name: Install universal-ctags
         run: |
@@ -163,7 +164,9 @@ jobs:
           path: symbol-list
 
       - name: Install abi-compliance-checker
-        run: sudo apt-get install abi-compliance-checker
+        run: |
+          sudo apt-get update
+          sudo apt-get install abi-compliance-checker
       - name: Compare ABI
         run: |
           if [ -s symbol-list/llvm.symbols ]; then

clang/docs/ReleaseNotes.rst

@@ -1058,8 +1058,13 @@ Bug Fixes to C++ Support
 - Fixed a substitution bug in transforming CTAD aliases when the type alias contains a non-pack template argument
   corresponding to a pack parameter (#GH124715)
 - Clang is now better at keeping track of friend function template instance contexts. (#GH55509)
+- Fixes matching of nested template template parameters. (#GH130362)
+- Correctly diagnoses template template paramters which have a pack parameter
+  not in the last position.
 - Fixed an integer overflow bug in computing template parameter depths when synthesizing CTAD guides. (#GH128691)
 - Fixed an incorrect pointer access when checking access-control on concepts. (#GH131530)
+- Fixed various alias CTAD bugs involving variadic template arguments. (#GH123591), (#GH127539), (#GH129077),
+  (#GH129620), and (#GH129998).
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^

clang/include/clang/Sema/Sema.h

@@ -11279,14 +11279,16 @@ class Sema final : public SemaBase {
 
   /// The context in which we are checking a template parameter list.
   enum TemplateParamListContext {
-    TPC_ClassTemplate,
-    TPC_VarTemplate,
+    // For this context, Class, Variable, TypeAlias, and non-pack Template
+    // Template Parameters are treated uniformly.
+    TPC_Other,
+
     TPC_FunctionTemplate,
     TPC_ClassTemplateMember,
     TPC_FriendClassTemplate,
     TPC_FriendFunctionTemplate,
     TPC_FriendFunctionTemplateDefinition,
-    TPC_TypeAliasTemplate
+    TPC_TemplateTemplateParameterPack,
   };
 
   /// Checks the validity of a template parameter list, possibly

clang/lib/Driver/ToolChains/Hexagon.cpp

@@ -313,6 +313,7 @@ constructHexagonLinkArgs(Compilation &C, const JobAction &JA,
                                      // handled somewhere else.
   Args.ClaimAllArgs(options::OPT_static_libgcc);
 
+  CmdArgs.push_back("--eh-frame-hdr");
   //----------------------------------------------------------------------------
   //
   //----------------------------------------------------------------------------
@@ -802,9 +803,7 @@ bool HexagonToolChain::isAutoHVXEnabled(const llvm::opt::ArgList &Args) {
 // Returns the default CPU for Hexagon. This is the default compilation target
 // if no Hexagon processor is selected at the command-line.
 //
-StringRef HexagonToolChain::GetDefaultCPU() {
-  return "hexagonv60";
-}
+StringRef HexagonToolChain::GetDefaultCPU() { return "hexagonv68"; }
 
 StringRef HexagonToolChain::GetTargetCPUVersion(const ArgList &Args) {
   Arg *CpuArg = nullptr;

clang/lib/Sema/SemaDecl.cpp

@@ -8145,7 +8145,7 @@ NamedDecl *Sema::ActOnVariableDeclarator(
               (D.getCXXScopeSpec().isSet() && DC && DC->isRecord() &&
                DC->isDependentContext())
                   ? TPC_ClassTemplateMember
-                  : TPC_VarTemplate))
+                  : TPC_Other))
         NewVD->setInvalidDecl();
 
       // If we are providing an explicit specialization of a static variable

clang/lib/Sema/SemaDeclCXX.cpp

@@ -13533,7 +13533,7 @@ Decl *Sema::ActOnAliasDeclaration(Scope *S, AccessSpecifier AS,
     // Merge any previous default template arguments into our parameters,
     // and check the parameter list.
     if (CheckTemplateParameterList(TemplateParams, OldTemplateParams,
-                                   TPC_TypeAliasTemplate))
+                                   TPC_Other))
       return nullptr;
 
     TypeAliasTemplateDecl *NewDecl =

clang/lib/Sema/SemaTemplate.cpp

@@ -1591,8 +1591,16 @@ NamedDecl *Sema::ActOnTemplateTemplateParameter(
   assert(S->isTemplateParamScope() &&
          "Template template parameter not in template parameter scope!");
 
-  // Construct the parameter object.
   bool IsParameterPack = EllipsisLoc.isValid();
+
+  bool Invalid = false;
+  if (CheckTemplateParameterList(
+          Params,
+          /*OldParams=*/nullptr,
+          IsParameterPack ? TPC_TemplateTemplateParameterPack : TPC_Other))
+    Invalid = true;
+
+  // Construct the parameter object.
   TemplateTemplateParmDecl *Param = TemplateTemplateParmDecl::Create(
       Context, Context.getTranslationUnitDecl(),
       NameLoc.isInvalid() ? TmpLoc : NameLoc, Depth, Position, IsParameterPack,
@@ -1615,9 +1623,12 @@ NamedDecl *Sema::ActOnTemplateTemplateParameter(
   if (Params->size() == 0) {
     Diag(Param->getLocation(), diag::err_template_template_parm_no_parms)
     << SourceRange(Params->getLAngleLoc(), Params->getRAngleLoc());
-    Param->setInvalidDecl();
+    Invalid = true;
   }
 
+  if (Invalid)
+    Param->setInvalidDecl();
+
   // C++0x [temp.param]p9:
   //   A default template-argument may be specified for any kind of
   //   template-parameter that is not a template parameter pack.
@@ -2066,7 +2077,7 @@ DeclResult Sema::CheckClassTemplate(
            SemanticContext->isDependentContext())
               ? TPC_ClassTemplateMember
           : TUK == TagUseKind::Friend ? TPC_FriendClassTemplate
-                                      : TPC_ClassTemplate,
+                                      : TPC_Other,
           SkipBody))
     Invalid = true;
 
@@ -2208,9 +2219,8 @@ static bool DiagnoseDefaultTemplateArgument(Sema &S,
                                             SourceLocation ParamLoc,
                                             SourceRange DefArgRange) {
   switch (TPC) {
-  case Sema::TPC_ClassTemplate:
-  case Sema::TPC_VarTemplate:
-  case Sema::TPC_TypeAliasTemplate:
+  case Sema::TPC_Other:
+  case Sema::TPC_TemplateTemplateParameterPack:
     return false;
 
   case Sema::TPC_FunctionTemplate:
@@ -2383,8 +2393,11 @@ bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
         MissingDefaultArg = true;
     } else if (NonTypeTemplateParmDecl *NewNonTypeParm
                = dyn_cast<NonTypeTemplateParmDecl>(*NewParam)) {
-      // Check for unexpanded parameter packs.
-      if (!NewNonTypeParm->isParameterPack() &&
+      // Check for unexpanded parameter packs, except in a template template
+      // parameter pack, as in those any unexpanded packs should be expanded
+      // along with the parameter itself.
+      if (TPC != TPC_TemplateTemplateParameterPack &&
+          !NewNonTypeParm->isParameterPack() &&
           DiagnoseUnexpandedParameterPack(NewNonTypeParm->getLocation(),
                                           NewNonTypeParm->getTypeSourceInfo(),
                                           UPPC_NonTypeTemplateParameterType)) {
@@ -2492,8 +2505,7 @@ bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
     //   If a template parameter of a primary class template or alias template
     //   is a template parameter pack, it shall be the last template parameter.
     if (SawParameterPack && (NewParam + 1) != NewParamEnd &&
-        (TPC == TPC_ClassTemplate || TPC == TPC_VarTemplate ||
-         TPC == TPC_TypeAliasTemplate)) {
+        (TPC == TPC_Other || TPC == TPC_TemplateTemplateParameterPack)) {
       Diag((*NewParam)->getLocation(),
            diag::err_template_param_pack_must_be_last_template_parameter);
       Invalid = true;
@@ -2526,8 +2538,8 @@ bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
           << PrevModuleName;
       Invalid = true;
     } else if (MissingDefaultArg &&
-               (TPC == TPC_ClassTemplate || TPC == TPC_FriendClassTemplate ||
-                TPC == TPC_VarTemplate || TPC == TPC_TypeAliasTemplate)) {
+               (TPC == TPC_Other || TPC == TPC_TemplateTemplateParameterPack ||
+                TPC == TPC_FriendClassTemplate)) {
       // C++ 23[temp.param]p14:
       // If a template-parameter of a class template, variable template, or
       // alias template has a default template argument, each subsequent

clang/lib/Sema/SemaTemplateDeduction.cpp

@@ -3427,9 +3427,9 @@ static TemplateDeductionResult FinishTemplateArgumentDeduction(
       if (!P.isPackExpansion() && !A.isPackExpansion()) {
         Info.Param =
             makeTemplateParameter(Template->getTemplateParameters()->getParam(
-                (PsStack.empty() ? TemplateArgs.end()
-                                 : PsStack.front().begin()) -
-                TemplateArgs.begin()));
+                (AsStack.empty() ? CTAI.CanonicalConverted.end()
+                                 : AsStack.front().begin()) -
+                1 - CTAI.CanonicalConverted.begin()));
         Info.FirstArg = P;
         Info.SecondArg = A;
         return TemplateDeductionResult::NonDeducedMismatch;
@@ -6625,17 +6625,19 @@ bool Sema::isTemplateTemplateParameterAtLeastAsSpecializedAs(
 
   TemplateDeductionResult TDK;
   runWithSufficientStackSpace(Info.getLocation(), [&] {
-    TDK = ::FinishTemplateArgumentDeduction(
-        *this, AArg, /*IsPartialOrdering=*/true, PArgs, Deduced, Info);
+    TDK = ::FinishTemplateArgumentDeduction(*this, AArg, PartialOrdering, PArgs,
+                                            Deduced, Info);
   });
   switch (TDK) {
   case TemplateDeductionResult::Success:
     return true;
 
   // It doesn't seem possible to get a non-deduced mismatch when partial
-  // ordering TTPs.
+  // ordering TTPs, except with an invalid template parameter list which has
+  // a parameter after a pack.
   case TemplateDeductionResult::NonDeducedMismatch:
-    llvm_unreachable("Unexpected NonDeducedMismatch");
+    assert(PArg->isInvalidDecl() && "Unexpected NonDeducedMismatch");
+    return false;
 
   // Substitution failures should have already been diagnosed.
   case TemplateDeductionResult::AlreadyDiagnosed:

clang/lib/Sema/SemaTemplateDeductionGuide.cpp

@@ -377,12 +377,10 @@ struct ConvertConstructorToDeductionGuideTransform {
         if (NestedPattern)
           Args.addOuterRetainedLevels(NestedPattern->getTemplateDepth());
         auto [Depth, Index] = getDepthAndIndex(Param);
-        // Depth can still be 0 if FTD belongs to an explicit class template
-        // specialization with an empty template parameter list. In that case,
-        // we don't want the NewDepth to overflow, and it should remain 0.
-        assert(Depth ||
-               cast<ClassTemplateSpecializationDecl>(FTD->getDeclContext())
-                   ->isExplicitSpecialization());
+        // Depth can be 0 if FTD belongs to a non-template class/a class
+        // template specialization with an empty template parameter list. In
+        // that case, we don't want the NewDepth to overflow, and it should
+        // remain 0.
         NamedDecl *NewParam = transformTemplateParameter(
             SemaRef, DC, Param, Args, Index + Depth1IndexAdjustment,
             Depth ? Depth - 1 : 0);
@@ -989,6 +987,19 @@ getRHSTemplateDeclAndArgs(Sema &SemaRef, TypeAliasTemplateDecl *AliasTemplate) {
   return {Template, AliasRhsTemplateArgs};
 }
 
+bool IsNonDeducedArgument(const TemplateArgument &TA) {
+  // The following cases indicate the template argument is non-deducible:
+  //   1. The result is null. E.g. When it comes from a default template
+  //   argument that doesn't appear in the alias declaration.
+  //   2. The template parameter is a pack and that cannot be deduced from
+  //   the arguments within the alias declaration.
+  // Non-deducible template parameters will persist in the transformed
+  // deduction guide.
+  return TA.isNull() ||
+         (TA.getKind() == TemplateArgument::Pack &&
+          llvm::any_of(TA.pack_elements(), IsNonDeducedArgument));
+}
+
 // Build deduction guides for a type alias template from the given underlying
 // deduction guide F.
 FunctionTemplateDecl *
@@ -1057,7 +1068,8 @@ BuildDeductionGuideForTypeAlias(Sema &SemaRef,
   // !!NOTE: DeduceResults respects the sequence of template parameters of
   // the deduction guide f.
   for (unsigned Index = 0; Index < DeduceResults.size(); ++Index) {
-    if (const auto &D = DeduceResults[Index]; !D.isNull()) // Deduced
+    const auto &D = DeduceResults[Index];
+    if (!IsNonDeducedArgument(D))
       DeducedArgs.push_back(D);
     else
       NonDeducedTemplateParamsInFIndex.push_back(Index);
@@ -1121,7 +1133,7 @@ BuildDeductionGuideForTypeAlias(Sema &SemaRef,
   Args.addOuterTemplateArguments(TransformedDeducedAliasArgs);
   for (unsigned Index = 0; Index < DeduceResults.size(); ++Index) {
     const auto &D = DeduceResults[Index];
-    if (D.isNull()) {
+    if (IsNonDeducedArgument(D)) {
       // 2): Non-deduced template parameters would be substituted later.
       continue;
     }