[clang] Revert "Reapply "[Clang][Sema] Refactor collection of multi-level template argument lists (#106585, #111173)" (#111852)" (PR #115159)

via cfe-commits cfe-commits at lists.llvm.org
Wed Nov 6 05:50:34 PST 2024


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-modules

Author: Krystian Stasiowski (sdkrystian)

<details>
<summary>Changes</summary>

This reverts commit 2bb3d3a3f32ffaef3d9b6a27db7f1941f0cb1136.

---

Patch is 105.20 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/115159.diff


21 Files Affected:

- (modified) clang/docs/ReleaseNotes.rst (-3) 
- (modified) clang/include/clang/AST/DeclTemplate.h (+36-59) 
- (modified) clang/include/clang/Sema/Sema.h (+19-6) 
- (modified) clang/lib/AST/Decl.cpp (+19-18) 
- (modified) clang/lib/AST/DeclCXX.cpp (+6-8) 
- (modified) clang/lib/AST/DeclTemplate.cpp (+16-14) 
- (modified) clang/lib/Sema/SemaConcept.cpp (+16-11) 
- (modified) clang/lib/Sema/SemaDecl.cpp (+17-14) 
- (modified) clang/lib/Sema/SemaDeclCXX.cpp (+2-2) 
- (modified) clang/lib/Sema/SemaInit.cpp (+1-1) 
- (modified) clang/lib/Sema/SemaTemplate.cpp (+89-83) 
- (modified) clang/lib/Sema/SemaTemplateDeduction.cpp (+30-3) 
- (modified) clang/lib/Sema/SemaTemplateDeductionGuide.cpp (+29-16) 
- (modified) clang/lib/Sema/SemaTemplateInstantiate.cpp (+385-362) 
- (modified) clang/lib/Sema/SemaTemplateInstantiateDecl.cpp (+9-37) 
- (modified) clang/lib/Serialization/ASTReader.cpp (+1-2) 
- (modified) clang/lib/Serialization/ASTReaderDecl.cpp (+8-8) 
- (modified) clang/lib/Serialization/ASTWriterDecl.cpp (+10-7) 
- (removed) clang/test/CXX/temp/temp.constr/temp.constr.decl/p4.cpp (-175) 
- (removed) clang/test/CXX/temp/temp.spec/temp.expl.spec/p7.cpp (-228) 
- (modified) clang/test/Modules/cxx-templates.cpp (+3-1) 


``````````diff
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 88621809bad7e2..d60d88920c6d0f 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -569,9 +569,6 @@ Bug Fixes to C++ Support
   in certain friend declarations. (#GH93099)
 - Clang now instantiates the correct lambda call operator when a lambda's class type is
   merged across modules. (#GH110401)
-- Clang now uses the correct set of template argument lists when comparing the constraints of
-  out-of-line definitions and member templates explicitly specialized for a given implicit instantiation of
-  a class template. (#GH102320)
 - Fix a crash when parsing a pseudo destructor involving an invalid type. (#GH111460)
 - Fixed an assertion failure when invoking recovery call expressions with explicit attributes
   and undeclared templates. (#GH107047), (#GH49093)
diff --git a/clang/include/clang/AST/DeclTemplate.h b/clang/include/clang/AST/DeclTemplate.h
index a572e3380f1655..e4bf54c3d77b7f 100644
--- a/clang/include/clang/AST/DeclTemplate.h
+++ b/clang/include/clang/AST/DeclTemplate.h
@@ -787,11 +787,15 @@ class RedeclarableTemplateDecl : public TemplateDecl,
                              EntryType *Entry, void *InsertPos);
 
   struct CommonBase {
-    CommonBase() {}
+    CommonBase() : InstantiatedFromMember(nullptr, false) {}
 
     /// The template from which this was most
     /// directly instantiated (or null).
-    RedeclarableTemplateDecl *InstantiatedFromMember = nullptr;
+    ///
+    /// The boolean value indicates whether this template
+    /// was explicitly specialized.
+    llvm::PointerIntPair<RedeclarableTemplateDecl *, 1, bool>
+        InstantiatedFromMember;
 
     /// If non-null, points to an array of specializations (including
     /// partial specializations) known only by their external declaration IDs.
@@ -802,19 +806,14 @@ class RedeclarableTemplateDecl : public TemplateDecl,
   };
 
   /// Pointer to the common data shared by all declarations of this
-  /// template, and a flag indicating if the template is a member
-  /// specialization.
-  mutable llvm::PointerIntPair<CommonBase *, 1, bool> Common;
-
-  CommonBase *getCommonPtrInternal() const { return Common.getPointer(); }
+  /// template.
+  mutable CommonBase *Common = nullptr;
 
   /// Retrieves the "common" pointer shared by all (re-)declarations of
   /// the same template. Calling this routine may implicitly allocate memory
   /// for the common pointer.
   CommonBase *getCommonPtr() const;
 
-  void setCommonPtr(CommonBase *C) const { Common.setPointer(C); }
-
   virtual CommonBase *newCommon(ASTContext &C) const = 0;
 
   // Construct a template decl with name, parameters, and templated element.
@@ -855,22 +854,15 @@ class RedeclarableTemplateDecl : public TemplateDecl,
   /// template<> template<typename T>
   /// struct X<int>::Inner { /* ... */ };
   /// \endcode
-  bool isMemberSpecialization() const { return Common.getInt(); }
-
-  /// Determines whether any redeclaration of this template was
-  /// a specialization of a member template.
-  bool hasMemberSpecialization() const {
-    for (const auto *D : redecls()) {
-      if (D->isMemberSpecialization())
-        return true;
-    }
-    return false;
+  bool isMemberSpecialization() const {
+    return getCommonPtr()->InstantiatedFromMember.getInt();
   }
 
   /// Note that this member template is a specialization.
   void setMemberSpecialization() {
-    assert(!isMemberSpecialization() && "already a member specialization");
-    Common.setInt(true);
+    assert(getCommonPtr()->InstantiatedFromMember.getPointer() &&
+           "Only member templates can be member template specializations");
+    getCommonPtr()->InstantiatedFromMember.setInt(true);
   }
 
   /// Retrieve the member template from which this template was
@@ -910,12 +902,12 @@ class RedeclarableTemplateDecl : public TemplateDecl,
   /// void X<T>::f(T, U);
   /// \endcode
   RedeclarableTemplateDecl *getInstantiatedFromMemberTemplate() const {
-    return getCommonPtr()->InstantiatedFromMember;
+    return getCommonPtr()->InstantiatedFromMember.getPointer();
   }
 
   void setInstantiatedFromMemberTemplate(RedeclarableTemplateDecl *TD) {
-    assert(!getCommonPtr()->InstantiatedFromMember);
-    getCommonPtr()->InstantiatedFromMember = TD;
+    assert(!getCommonPtr()->InstantiatedFromMember.getPointer());
+    getCommonPtr()->InstantiatedFromMember.setPointer(TD);
   }
 
   /// Retrieve the "injected" template arguments that correspond to the
@@ -1997,8 +1989,6 @@ class ClassTemplateSpecializationDecl : public CXXRecordDecl,
   /// template arguments have been deduced.
   void setInstantiationOf(ClassTemplatePartialSpecializationDecl *PartialSpec,
                           const TemplateArgumentList *TemplateArgs) {
-    assert(!isa<ClassTemplatePartialSpecializationDecl>(this) &&
-           "A partial specialization cannot be instantiated from a template");
     assert(!SpecializedTemplate.is<SpecializedPartialSpecialization*>() &&
            "Already set to a class template partial specialization!");
     auto *PS = new (getASTContext()) SpecializedPartialSpecialization();
@@ -2010,8 +2000,6 @@ class ClassTemplateSpecializationDecl : public CXXRecordDecl,
   /// Note that this class template specialization is an instantiation
   /// of the given class template.
   void setInstantiationOf(ClassTemplateDecl *TemplDecl) {
-    assert(!isa<ClassTemplatePartialSpecializationDecl>(this) &&
-           "A partial specialization cannot be instantiated from a template");
     assert(!SpecializedTemplate.is<SpecializedPartialSpecialization*>() &&
            "Previously set to a class template partial specialization!");
     SpecializedTemplate = TemplDecl;
@@ -2205,22 +2193,18 @@ class ClassTemplatePartialSpecializationDecl
   /// struct X<int>::Inner<T*> { /* ... */ };
   /// \endcode
   bool isMemberSpecialization() const {
-    return InstantiatedFromMember.getInt();
-  }
-
-  /// Determines whether any redeclaration of this this class template partial
-  /// specialization was a specialization of a member partial specialization.
-  bool hasMemberSpecialization() const {
-    for (const auto *D : redecls()) {
-      if (cast<ClassTemplatePartialSpecializationDecl>(D)
-              ->isMemberSpecialization())
-        return true;
-    }
-    return false;
+    const auto *First =
+        cast<ClassTemplatePartialSpecializationDecl>(getFirstDecl());
+    return First->InstantiatedFromMember.getInt();
   }
 
   /// Note that this member template is a specialization.
-  void setMemberSpecialization() { return InstantiatedFromMember.setInt(true); }
+  void setMemberSpecialization() {
+    auto *First = cast<ClassTemplatePartialSpecializationDecl>(getFirstDecl());
+    assert(First->InstantiatedFromMember.getPointer() &&
+           "Only member templates can be member template specializations");
+    return First->InstantiatedFromMember.setInt(true);
+  }
 
   /// Retrieves the injected specialization type for this partial
   /// specialization.  This is not the same as the type-decl-type for
@@ -2290,6 +2274,8 @@ class ClassTemplateDecl : public RedeclarableTemplateDecl {
     return static_cast<Common *>(RedeclarableTemplateDecl::getCommonPtr());
   }
 
+  void setCommonPtr(Common *C) { RedeclarableTemplateDecl::Common = C; }
+
 public:
 
   friend class ASTDeclReader;
@@ -2772,8 +2758,6 @@ class VarTemplateSpecializationDecl : public VarDecl,
   /// template arguments have been deduced.
   void setInstantiationOf(VarTemplatePartialSpecializationDecl *PartialSpec,
                           const TemplateArgumentList *TemplateArgs) {
-    assert(!isa<VarTemplatePartialSpecializationDecl>(this) &&
-           "A partial specialization cannot be instantiated from a template");
     assert(!SpecializedTemplate.is<SpecializedPartialSpecialization *>() &&
            "Already set to a variable template partial specialization!");
     auto *PS = new (getASTContext()) SpecializedPartialSpecialization();
@@ -2785,8 +2769,6 @@ class VarTemplateSpecializationDecl : public VarDecl,
   /// Note that this variable template specialization is an instantiation
   /// of the given variable template.
   void setInstantiationOf(VarTemplateDecl *TemplDecl) {
-    assert(!isa<VarTemplatePartialSpecializationDecl>(this) &&
-           "A partial specialization cannot be instantiated from a template");
     assert(!SpecializedTemplate.is<SpecializedPartialSpecialization *>() &&
            "Previously set to a variable template partial specialization!");
     SpecializedTemplate = TemplDecl;
@@ -2977,23 +2959,18 @@ class VarTemplatePartialSpecializationDecl
   /// U* X<int>::Inner<T*> = (T*)(0) + 1;
   /// \endcode
   bool isMemberSpecialization() const {
-    return InstantiatedFromMember.getInt();
-  }
-
-  /// Determines whether any redeclaration of this this variable template
-  /// partial specialization was a specialization of a member partial
-  /// specialization.
-  bool hasMemberSpecialization() const {
-    for (const auto *D : redecls()) {
-      if (cast<VarTemplatePartialSpecializationDecl>(D)
-              ->isMemberSpecialization())
-        return true;
-    }
-    return false;
+    const auto *First =
+        cast<VarTemplatePartialSpecializationDecl>(getFirstDecl());
+    return First->InstantiatedFromMember.getInt();
   }
 
   /// Note that this member template is a specialization.
-  void setMemberSpecialization() { return InstantiatedFromMember.setInt(true); }
+  void setMemberSpecialization() {
+    auto *First = cast<VarTemplatePartialSpecializationDecl>(getFirstDecl());
+    assert(First->InstantiatedFromMember.getPointer() &&
+           "Only member templates can be member template specializations");
+    return First->InstantiatedFromMember.setInt(true);
+  }
 
   SourceRange getSourceRange() const override LLVM_READONLY;
 
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 93d98e1cbb9c81..aa2f5ff3ef7207 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -11328,9 +11328,9 @@ class Sema final : public SemaBase {
       CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
       const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
       AccessSpecifier AS, SourceLocation ModulePrivateLoc,
-      SourceLocation FriendLoc,
-      ArrayRef<TemplateParameterList *> OuterTemplateParamLists,
-      bool IsMemberSpecialization, SkipBodyInfo *SkipBody = nullptr);
+      SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
+      TemplateParameterList **OuterTemplateParamLists,
+      SkipBodyInfo *SkipBody = nullptr);
 
   /// Translates template arguments as provided by the parser
   /// into template arguments used by semantic analysis.
@@ -11369,8 +11369,7 @@ class Sema final : public SemaBase {
   DeclResult ActOnVarTemplateSpecialization(
       Scope *S, Declarator &D, TypeSourceInfo *DI, LookupResult &Previous,
       SourceLocation TemplateKWLoc, TemplateParameterList *TemplateParams,
-      StorageClass SC, bool IsPartialSpecialization,
-      bool IsMemberSpecialization);
+      StorageClass SC, bool IsPartialSpecialization);
 
   /// Get the specialization of the given variable template corresponding to
   /// the specified argument list, or a null-but-valid result if the arguments
@@ -13012,14 +13011,28 @@ class Sema final : public SemaBase {
   /// dealing with a specialization. This is only relevant for function
   /// template specializations.
   ///
+  /// \param Pattern If non-NULL, indicates the pattern from which we will be
+  /// instantiating the definition of the given declaration, \p ND. This is
+  /// used to determine the proper set of template instantiation arguments for
+  /// friend function template specializations.
+  ///
   /// \param ForConstraintInstantiation when collecting arguments,
   /// ForConstraintInstantiation indicates we should continue looking when
   /// encountering a lambda generic call operator, and continue looking for
   /// arguments on an enclosing class template.
+  ///
+  /// \param SkipForSpecialization when specified, any template specializations
+  /// in a traversal would be ignored.
+  /// \param ForDefaultArgumentSubstitution indicates we should continue looking
+  /// when encountering a specialized member function template, rather than
+  /// returning immediately.
   MultiLevelTemplateArgumentList getTemplateInstantiationArgs(
       const NamedDecl *D, const DeclContext *DC = nullptr, bool Final = false,
       std::optional<ArrayRef<TemplateArgument>> Innermost = std::nullopt,
-      bool RelativeToPrimary = false, bool ForConstraintInstantiation = false);
+      bool RelativeToPrimary = false, const FunctionDecl *Pattern = nullptr,
+      bool ForConstraintInstantiation = false,
+      bool SkipForSpecialization = false,
+      bool ForDefaultArgumentSubstitution = false);
 
   /// RAII object to handle the state changes required to synthesize
   /// a function body.
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 86913763ef9ff5..8204e3509dd563 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -2708,21 +2708,21 @@ VarDecl *VarDecl::getTemplateInstantiationPattern() const {
     if (isTemplateInstantiation(VDTemplSpec->getTemplateSpecializationKind())) {
       auto From = VDTemplSpec->getInstantiatedFrom();
       if (auto *VTD = From.dyn_cast<VarTemplateDecl *>()) {
-        while (!VTD->hasMemberSpecialization()) {
-          if (auto *NewVTD = VTD->getInstantiatedFromMemberTemplate())
-            VTD = NewVTD;
-          else
+        while (!VTD->isMemberSpecialization()) {
+          auto *NewVTD = VTD->getInstantiatedFromMemberTemplate();
+          if (!NewVTD)
             break;
+          VTD = NewVTD;
         }
         return getDefinitionOrSelf(VTD->getTemplatedDecl());
       }
       if (auto *VTPSD =
               From.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
-        while (!VTPSD->hasMemberSpecialization()) {
-          if (auto *NewVTPSD = VTPSD->getInstantiatedFromMember())
-            VTPSD = NewVTPSD;
-          else
+        while (!VTPSD->isMemberSpecialization()) {
+          auto *NewVTPSD = VTPSD->getInstantiatedFromMember();
+          if (!NewVTPSD)
             break;
+          VTPSD = NewVTPSD;
         }
         return getDefinitionOrSelf<VarDecl>(VTPSD);
       }
@@ -2731,14 +2731,15 @@ VarDecl *VarDecl::getTemplateInstantiationPattern() const {
 
   // If this is the pattern of a variable template, find where it was
   // instantiated from. FIXME: Is this necessary?
-  if (VarTemplateDecl *VTD = VD->getDescribedVarTemplate()) {
-    while (!VTD->hasMemberSpecialization()) {
-      if (auto *NewVTD = VTD->getInstantiatedFromMemberTemplate())
-        VTD = NewVTD;
-      else
+  if (VarTemplateDecl *VarTemplate = VD->getDescribedVarTemplate()) {
+    while (!VarTemplate->isMemberSpecialization()) {
+      auto *NewVT = VarTemplate->getInstantiatedFromMemberTemplate();
+      if (!NewVT)
         break;
+      VarTemplate = NewVT;
     }
-    return getDefinitionOrSelf(VTD->getTemplatedDecl());
+
+    return getDefinitionOrSelf(VarTemplate->getTemplatedDecl());
   }
 
   if (VD == this)
@@ -4153,11 +4154,11 @@ FunctionDecl::getTemplateInstantiationPattern(bool ForDefinition) const {
   if (FunctionTemplateDecl *Primary = getPrimaryTemplate()) {
     // If we hit a point where the user provided a specialization of this
     // template, we're done looking.
-    while (!ForDefinition || !Primary->hasMemberSpecialization()) {
-      if (auto *NewPrimary = Primary->getInstantiatedFromMemberTemplate())
-        Primary = NewPrimary;
-      else
+    while (!ForDefinition || !Primary->isMemberSpecialization()) {
+      auto *NewPrimary = Primary->getInstantiatedFromMemberTemplate();
+      if (!NewPrimary)
         break;
+      Primary = NewPrimary;
     }
 
     return getDefinitionOrSelf(Primary->getTemplatedDecl());
diff --git a/clang/lib/AST/DeclCXX.cpp b/clang/lib/AST/DeclCXX.cpp
index db0ea62a2323eb..4394a0724b3c17 100644
--- a/clang/lib/AST/DeclCXX.cpp
+++ b/clang/lib/AST/DeclCXX.cpp
@@ -2030,21 +2030,19 @@ const CXXRecordDecl *CXXRecordDecl::getTemplateInstantiationPattern() const {
   if (auto *TD = dyn_cast<ClassTemplateSpecializationDecl>(this)) {
     auto From = TD->getInstantiatedFrom();
     if (auto *CTD = From.dyn_cast<ClassTemplateDecl *>()) {
-      while (!CTD->hasMemberSpecialization()) {
-        if (auto *NewCTD = CTD->getInstantiatedFromMemberTemplate())
-          CTD = NewCTD;
-        else
+      while (auto *NewCTD = CTD->getInstantiatedFromMemberTemplate()) {
+        if (NewCTD->isMemberSpecialization())
           break;
+        CTD = NewCTD;
       }
       return GetDefinitionOrSelf(CTD->getTemplatedDecl());
     }
     if (auto *CTPSD =
             From.dyn_cast<ClassTemplatePartialSpecializationDecl *>()) {
-      while (!CTPSD->hasMemberSpecialization()) {
-        if (auto *NewCTPSD = CTPSD->getInstantiatedFromMemberTemplate())
-          CTPSD = NewCTPSD;
-        else
+      while (auto *NewCTPSD = CTPSD->getInstantiatedFromMember()) {
+        if (NewCTPSD->isMemberSpecialization())
           break;
+        CTPSD = NewCTPSD;
       }
       return GetDefinitionOrSelf(CTPSD);
     }
diff --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
index 755ec72f00bf77..a221d619672b38 100644
--- a/clang/lib/AST/DeclTemplate.cpp
+++ b/clang/lib/AST/DeclTemplate.cpp
@@ -320,16 +320,16 @@ bool TemplateDecl::isTypeAlias() const {
 void RedeclarableTemplateDecl::anchor() {}
 
 RedeclarableTemplateDecl::CommonBase *RedeclarableTemplateDecl::getCommonPtr() const {
-  if (CommonBase *C = getCommonPtrInternal())
-    return C;
+  if (Common)
+    return Common;
 
   // Walk the previous-declaration chain until we either find a declaration
   // with a common pointer or we run out of previous declarations.
   SmallVector<const RedeclarableTemplateDecl *, 2> PrevDecls;
   for (const RedeclarableTemplateDecl *Prev = getPreviousDecl(); Prev;
        Prev = Prev->getPreviousDecl()) {
-    if (CommonBase *C = Prev->getCommonPtrInternal()) {
-      setCommonPtr(C);
+    if (Prev->Common) {
+      Common = Prev->Common;
       break;
     }
 
@@ -337,18 +337,18 @@ RedeclarableTemplateDecl::CommonBase *RedeclarableTemplateDecl::getCommonPtr() c
   }
 
   // If we never found a common pointer, allocate one now.
-  if (!getCommonPtrInternal()) {
+  if (!Common) {
     // FIXME: If any of the declarations is from an AST file, we probably
     // need an update record to add the common data.
 
-    setCommonPtr(newCommon(getASTContext()));
+    Common = newCommon(getASTContext());
   }
 
   // Update any previous declarations we saw with the common pointer.
   for (const RedeclarableTemplateDecl *Prev : PrevDecls)
-    Prev->setCommonPtr(getCommonPtrInternal());
+    Prev->Common = Common;
 
-  return getCommonPtrInternal();
+  return Common;
 }
 
 void RedeclarableTemplateDecl::loadLazySpecializationsImpl() const {
@@ -458,17 +458,19 @@ void FunctionTemplateDecl::addSpecialization(
 }
 
 void FunctionTemplateDecl::mergePrevDecl(FunctionTemplateDecl *Prev) {
+  using Base = RedeclarableTemplateDecl;
+
   // If we haven't created a common pointer yet, then it can just be created
   // with the usual method.
-  if (!getCommonPtrInternal())
+  if (!Base::Common)
     return;
 
-  Common *ThisCommon = static_cast<Common *>(getCommonPtrInternal());
+  Common *ThisCommon = static_cast<Common *>(Base::Common);
   Common *PrevCommon = nullptr;
   SmallVector<FunctionTemplateDecl *, 8> PreviousDecls;
   for (; Prev; Prev = Prev->getPreviousDecl()) {
-    if (CommonBase *C = Prev->getCommonPtrInternal()) {
-      PrevCommon = static_cast<Common *>(C);
+    if (Prev->Base::Common) {
+      PrevCommon = static_cast<Common *>(Prev->Base::Common);
       break;
     }
     PreviousDecls.push_back(Prev);
@@ -478,7 +480,7 @@ void FunctionTemplateDecl::mergePrevDecl(FunctionTemplateDecl *Prev) {
   // use this common pointer.
   if (!PrevCommon) {
     for (auto *D : PreviousDecls)
-      D->setCommonPtr(ThisCommon);
+      D->Base::Common = ThisCommon;
     return;
   }
 
@@ -486,7 +488,7 @@ void FunctionTemplateDecl::mergePrevDecl(FunctionTemplateDecl *Prev) {
   assert(ThisCommon->Specializations.size(...
[truncated]

``````````

</details>


https://github.com/llvm/llvm-project/pull/115159


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