[clang] Apply missing changes from several Sema-related commits

cherry-picked:
8009bbe [email protected]              Tue Apr 30 14:25:09 2024 -0400 Reapply "[Clang][Sema] Diagnose class member access expressions naming non-existent members of the current instantiation prior to instantiation in the absence of dependent base classes (llvm#84050)" (llvm#90152)
3191e0b [email protected]              Fri May  3 17:07:52 2024 -0400 [Clang][Sema] Fix template name lookup for operator= (llvm#90999)
62b5b61 [email protected]              Wed May  8 20:49:59 2024 -0400 [Clang][Sema] Fix lookup of dependent operator= outside of complete-class contexts (llvm#91498)
75ebcbf [email protected]              Thu May  9 16:34:40 2024 -0400 [Clang][Sema] Revert changes to operator= lookup in templated classes from llvm#91498, llvm#90999, and llvm#90152 (llvm#91620)
596a9c1 [email protected]              Mon May 13 12:24:46 2024 -0400 [Clang][Sema] Fix bug where operator-> typo corrects in the current instantiation (llvm#91972)
fd87d76 [email protected]              Mon May 20 13:55:01 2024 -0400 [Clang][Sema] Don't build CXXDependentScopeMemberExprs for potentially implicit class member access expressions (llvm#92318)
e75b58c [email protected]              Mon May 20 14:50:58 2024 -0400 [Clang][Sema] Do not add implicit 'const' when matching constexpr function template explicit specializations after C++14 (llvm#92449)
bae2c54 [email protected] Mon Jul  1 20:55:57 2024 +0300 [clang][NFC] Move documentation of `Sema` functions into `Sema.h`
e6d305e [email protected]                 Mon Sep  4 16:54:42 2023 +0200 Add support of Windows Trace Logging macros

Change-Id: I521b2ebabd7eb9a0df78c577992bfd8508ba44fd

Author: macurtis-amd

clang/docs/ReleaseNotes.rst

@@ -465,6 +465,8 @@ Bug Fixes in This Version
 - Fixed a crash when diagnosing format strings and encountering an empty
   delimited escape sequence (e.g., ``"\o{}"``). #GH102218
 - Fixed a crash using ``__array_rank`` on 64-bit targets. (#GH113044).
+- Support MSVC predefined macro expressions in constant expressions and in
+  local structs.
 - The warning emitted for an unsupported register variable type now points to
   the unsupported type instead of the ``register`` keyword (#GH109776).
 
@@ -542,6 +544,9 @@ Bug Fixes to C++ Support
 - Fixed an assertion failure in debug mode, and potential crashes in release mode, when
   diagnosing a failed cast caused indirectly by a failed implicit conversion to the type of the constructor parameter.
 - Fixed an assertion failure by adjusting integral to boolean vector conversions (#GH108326)
+- Clang no longer treats ``constexpr`` class scope function template specializations of non-static members
+  as implicitly ``const`` in language modes after C++11.
+- Mangle friend function templates with a constraint that depends on a template parameter from an enclosing template as members of the enclosing class. (#GH110247)
 - Fixed an issue deducing non-type template arguments of reference type. (#GH73460)
 - Fixed an issue in constraint evaluation, where type constraints on the lambda expression
   containing outer unexpanded parameters were not correctly expanded. (#GH101754)

clang/include/clang/Sema/Sema.h

@@ -3980,10 +3980,6 @@ class Sema final : public SemaBase {
   void ActOnReenterFunctionContext(Scope *S, Decl *D);
   void ActOnExitFunctionContext();
 
-  /// getCurLocalScopeDecl - Return the Decl for either of:
-  /// block, lambda, captured statement, function, or nullptr.
-  Decl *getCurLocalScopeDecl();
-
   /// Add this decl to the scope shadowed decl chains.
   void PushOnScopeChains(NamedDecl *D, Scope *S, bool AddToContext = true);
 
@@ -6731,6 +6727,10 @@ class Sema final : public SemaBase {
   bool UseArgumentDependentLookup(const CXXScopeSpec &SS, const LookupResult &R,
                                   bool HasTrailingLParen);
 
+  /// BuildQualifiedDeclarationNameExpr - Build a C++ qualified
+  /// declaration name, generally during template instantiation.
+  /// There's a large number of things which don't need to be done along
+  /// this path.
   ExprResult BuildQualifiedDeclarationNameExpr(
       CXXScopeSpec &SS, const DeclarationNameInfo &NameInfo,
       bool IsAddressOfOperand, TypeSourceInfo **RecoveryTSI = nullptr);

clang/lib/Sema/Sema.cpp

@@ -1578,18 +1578,6 @@ NamedDecl *Sema::getCurFunctionOrMethodDecl() const {
   return nullptr;
 }
 
-Decl *Sema::getCurLocalScopeDecl() {
-  if (const BlockScopeInfo *BSI = getCurBlock())
-    return BSI->TheDecl;
-  if (const LambdaScopeInfo *LSI = getCurLambda())
-    return LSI->CallOperator;
-  if (const CapturedRegionScopeInfo *CSI = getCurCapturedRegion())
-    return CSI->TheCapturedDecl;
-  if (NamedDecl *ND = getCurFunctionOrMethodDecl())
-    return ND;
-  return nullptr;
-}
-
 LangAS Sema::getDefaultCXXMethodAddrSpace() const {
   if (getLangOpts().OpenCL)
     return getASTContext().getDefaultOpenCLPointeeAddrSpace();

clang/lib/Sema/SemaDeclCXX.cpp

@@ -2629,10 +2629,6 @@ bool Sema::isCurrentClassNameTypo(IdentifierInfo *&II, const CXXScopeSpec *SS) {
   return false;
 }
 
-/// Check the validity of a C++ base class specifier.
-///
-/// \returns a new CXXBaseSpecifier if well-formed, emits diagnostics
-/// and returns NULL otherwise.
 CXXBaseSpecifier *Sema::CheckBaseSpecifier(CXXRecordDecl *Class,
                                            SourceRange SpecifierRange,
                                            bool Virtual, AccessSpecifier Access,

clang/lib/Sema/SemaExpr.cpp

@@ -663,7 +663,6 @@ ExprResult Sema::DefaultLvalueConversion(Expr *E) {
 
   // We don't want to throw lvalue-to-rvalue casts on top of
   // expressions of certain types in C++.
-
   if (getLangOpts().CPlusPlus) {
     if (T == Context.OverloadTy || T->isRecordType() ||
         (T->isDependentType() && !T->isAnyPointerType() &&
@@ -1895,15 +1894,6 @@ ExprResult Sema::CreateGenericSelectionExpr(
       ContainsUnexpandedParameterPack, ResultIndex);
 }
 
-/// getPredefinedExprDecl - Returns Decl of a given DeclContext that can be used
-/// to determine the value of a PredefinedExpr. This can be either a
-/// block, lambda, captured statement, function, otherwise a nullptr.
-static Decl *getPredefinedExprDecl(DeclContext *DC) {
-  while (DC && !isa<BlockDecl, CapturedDecl, FunctionDecl, ObjCMethodDecl>(DC))
-    DC = DC->getParent();
-  return cast_or_null<Decl>(DC);
-}
-
 static PredefinedIdentKind getPredefinedExprKind(tok::TokenKind Kind) {
   switch (Kind) {
   default:
@@ -1925,6 +1915,15 @@ static PredefinedIdentKind getPredefinedExprKind(tok::TokenKind Kind) {
   }
 }
 
+/// getPredefinedExprDecl - Returns Decl of a given DeclContext that can be used
+/// to determine the value of a PredefinedExpr. This can be either a
+/// block, lambda, captured statement, function, otherwise a nullptr.
+static Decl *getPredefinedExprDecl(DeclContext *DC) {
+  while (DC && !isa<BlockDecl, CapturedDecl, FunctionDecl, ObjCMethodDecl>(DC))
+    DC = DC->getParent();
+  return cast_or_null<Decl>(DC);
+}
+
 /// getUDSuffixLoc - Create a SourceLocation for a ud-suffix, given the
 /// location of the token and the offset of the ud-suffix within it.
 static SourceLocation getUDSuffixLoc(Sema &S, SourceLocation TokLoc,
@@ -2005,7 +2004,7 @@ Sema::ExpandFunctionLocalPredefinedMacros(ArrayRef<Token> Toks) {
   // Note: Although function local macros are defined only inside functions,
   // we ensure a valid `CurrentDecl` even outside of a function. This allows
   // expansion of macros into empty string literals without additional checks.
-  Decl *CurrentDecl = getCurLocalScopeDecl();
+  Decl *CurrentDecl = getPredefinedExprDecl(CurContext);
   if (!CurrentDecl)
     CurrentDecl = Context.getTranslationUnitDecl();
 
@@ -2698,34 +2697,6 @@ Sema::ActOnIdExpression(Scope *S, CXXScopeSpec &SS,
     return ExprError();
   }
 
-  // C++ [temp.dep.expr]p3:
-  //   An id-expression is type-dependent if it contains:
-  //     -- an identifier that was declared with a dependent type,
-  //        (note: handled after lookup)
-  //     -- a template-id that is dependent,
-  //        (note: handled in BuildTemplateIdExpr)
-  //     -- a conversion-function-id that specifies a dependent type,
-  //     -- a nested-name-specifier that contains a class-name that
-  //        names a dependent type.
-  // Determine whether this is a member of an unknown specialization;
-  // we need to handle these differently.
-  bool DependentID = false;
-  if (Name.getNameKind() == DeclarationName::CXXConversionFunctionName &&
-      Name.getCXXNameType()->isDependentType()) {
-    DependentID = true;
-  } else if (SS.isSet()) {
-    if (DeclContext *DC = computeDeclContext(SS, false)) {
-      if (RequireCompleteDeclContext(SS, DC))
-        return ExprError();
-    } else {
-      DependentID = true;
-    }
-  }
-
-  if (DependentID)
-    return ActOnDependentIdExpression(SS, TemplateKWLoc, NameInfo,
-                                      IsAddressOfOperand, TemplateArgs);
-
   // This specially handles arguments of attributes appertains to a type of C
   // struct field such that the name lookup within a struct finds the member
   // name, which is not the case for other contexts in C.

clang/lib/Sema/SemaExprMember.cpp

@@ -984,8 +984,9 @@ Sema::BuildMemberReferenceExpr(Expr *BaseExpr, QualType BaseExprType,
   // arrow operator was used with a dependent non-pointer object expression,
   // build a CXXDependentScopeMemberExpr.
   if (R.wasNotFoundInCurrentInstantiation() ||
-      (IsArrow && !BaseExprType->isPointerType() &&
-       BaseExprType->isDependentType()))
+      (R.getLookupName().getCXXOverloadedOperator() == OO_Equal &&
+       (SS.isSet() ? SS.getScopeRep()->isDependent()
+                   : BaseExprType->isDependentType())))
     return ActOnDependentMemberExpr(BaseExpr, BaseExprType, IsArrow, OpLoc, SS,
                                     TemplateKWLoc, FirstQualifierInScope,
                                     R.getLookupNameInfo(), TemplateArgs);
@@ -1322,8 +1323,8 @@ static ExprResult LookupMemberExpr(Sema &S, LookupResult &R,
       // was encountered while looking for the overloaded operator->.
       if (!S.getLangOpts().CPlusPlus) {
         S.Diag(OpLoc, diag::err_typecheck_member_reference_suggestion)
-          << BaseType << int(IsArrow) << BaseExpr.get()->getSourceRange()
-          << FixItHint::CreateReplacement(OpLoc, ".");
+            << BaseType << int(IsArrow) << BaseExpr.get()->getSourceRange()
+            << FixItHint::CreateReplacement(OpLoc, ".");
       }
       IsArrow = false;
     } else {
@@ -1349,7 +1350,7 @@ static ExprResult LookupMemberExpr(Sema &S, LookupResult &R,
   }
 
   // Handle field access to simple records.
-  if (BaseType->getAsRecordDecl() || BaseType->isDependentType()) {
+  if (BaseType->getAsRecordDecl()) {
     TypoExpr *TE = nullptr;
     if (LookupMemberExprInRecord(S, R, BaseExpr.get(), BaseType, OpLoc, IsArrow,
                                  SS, HasTemplateArgs, TemplateKWLoc, TE))

clang/lib/Sema/SemaLookup.cpp

@@ -1286,31 +1286,6 @@ bool Sema::CppLookupName(LookupResult &R, Scope *S) {
       if (DeclContext *DC = PreS->getEntity())
         DeclareImplicitMemberFunctionsWithName(*this, Name, R.getNameLoc(), DC);
   }
-  // C++23 [temp.dep.general]p2:
-  //   The component name of an unqualified-id is dependent if
-  //   - it is a conversion-function-id whose conversion-type-id
-  //     is dependent, or
-  //   - it is operator= and the current class is a templated entity, or
-  //   - the unqualified-id is the postfix-expression in a dependent call.
-  if (Name.getNameKind() == DeclarationName::CXXConversionFunctionName &&
-      Name.getCXXNameType()->isDependentType()) {
-    R.setNotFoundInCurrentInstantiation();
-    return false;
-  }
-
-  // If this is the name of an implicitly-declared special member function,
-  // go through the scope stack to implicitly declare
-  if (isImplicitlyDeclaredMemberFunctionName(Name)) {
-    for (Scope *PreS = S; PreS; PreS = PreS->getParent())
-      if (DeclContext *DC = PreS->getEntity()) {
-        if (DC->isDependentContext() && isa<CXXRecordDecl>(DC) &&
-            Name.getCXXOverloadedOperator() == OO_Equal) {
-          R.setNotFoundInCurrentInstantiation();
-          return false;
-        }
-        DeclareImplicitMemberFunctionsWithName(*this, Name, R.getNameLoc(), DC);
-      }
-  }
 
   // C++23 [temp.dep.general]p2:
   //   The component name of an unqualified-id is dependent if

clang/lib/Sema/SemaTemplate.cpp

@@ -4634,7 +4634,6 @@ ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
   return ULE;
 }
 
-// We actually only call this from template instantiation.
 ExprResult Sema::BuildQualifiedTemplateIdExpr(
     CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
     const DeclarationNameInfo &NameInfo,
@@ -9062,15 +9061,20 @@ bool Sema::CheckFunctionTemplateSpecialization(
                                 Ovl->getDeclContext()->getRedeclContext()))
         continue;
 
+      QualType FT = FD->getType();
+      // C++11 [dcl.constexpr]p8:
+      //   A constexpr specifier for a non-static member function that is not
+      //   a constructor declares that member function to be const.
+      //
       // When matching a constexpr member function template specialization
       // against the primary template, we don't yet know whether the
       // specialization has an implicit 'const' (because we don't know whether
       // it will be a static member function until we know which template it
-      // specializes), so adjust it now assuming it specializes this template.
-      QualType FT = FD->getType();
-      if (FD->isConstexpr()) {
-        CXXMethodDecl *OldMD =
-          dyn_cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl());
+      // specializes). This rule was removed in C++14.
+      if (auto *NewMD = dyn_cast<CXXMethodDecl>(FD);
+          !getLangOpts().CPlusPlus14 && NewMD && NewMD->isConstexpr() &&
+          !isa<CXXConstructorDecl, CXXDestructorDecl>(NewMD)) {
+        auto *OldMD = dyn_cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl());
         if (OldMD && OldMD->isConst()) {
           const FunctionProtoType *FPT = FT->castAs<FunctionProtoType>();
           FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();

clang/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p1.cpp

@@ -3,8 +3,6 @@
 // RUN: %clang_cc1 -triple %itanium_abi_triple -fsyntax-only -verify -std=c++17 %s
 // RUN: %clang_cc1 -triple %itanium_abi_triple -fsyntax-only -verify -std=c++2a %s
 
-// XFAIL: *
-
 // MSVC always adopted the C++17 rule that implies that constexpr variables are
 // implicitly inline, so do the test again.
 // RUN: %clang_cc1 -triple x86_64-windows-msvc -DMS_ABI -fsyntax-only -verify -std=c++11 %s
@@ -91,6 +89,9 @@ struct S {
   template<typename T> constexpr T f(); // expected-warning 0-1{{C++14}} expected-note 0-1{{candidate}}
   template <typename T>
   T g() const; // expected-note-re {{candidate template ignored: could not match 'T (){{( __attribute__\(\(thiscall\)\))?}} const' against 'char (){{( __attribute__\(\(thiscall\)\))?}}'}}
+#if __cplusplus >= 201402L
+  // expected-note@-2 {{candidate template ignored: could not match 'T () const' against 'int ()'}}
+#endif
 };
 
 // explicit specialization can differ in constepxr
@@ -102,13 +103,17 @@ template <> notlit S::f() const { return notlit(); }
 #if __cplusplus >= 201402L
 // expected-error@-2 {{no function template matches}}
 #endif
-template <> constexpr int S::g() { return 0; } // expected-note {{previous}}
+template <> constexpr int S::g() { return 0; }
 #if __cplusplus < 201402L
 // expected-warning@-2 {{C++14}}
+// expected-note@-3 {{previous}}
 #else
-// expected-error@-4 {{does not match any declaration in 'S'}}
+// expected-error@-5 {{no function template matches function template specialization 'g'}}
+#endif
+template <> int S::g() const;
+#if __cplusplus < 201402L
+// expected-error@-2 {{non-constexpr declaration of 'g<int>' follows constexpr declaration}}
 #endif
-template <> int S::g() const; // expected-error {{non-constexpr declaration of 'g<int>' follows constexpr declaration}}
 // specializations can drop the 'constexpr' but not the implied 'const'.
 template <> char S::g() { return 0; } // expected-error {{no function template matches}}
 template <> double S::g() const { return 0; } // ok

clang/test/CXX/temp/temp.res/temp.dep/temp.dep.type/p4.cpp

@@ -1,5 +1,4 @@
-// RUN:
-// DEACTIVATED: %clang_cc1 -Wno-unused-value -verify %s
+// RUN: %clang_cc1 -Wno-unused-value -verify %s
 
 namespace N0 {
   struct A {