Merge branch 'main' into users/meinersbur/mlir_tile

Author: Meinersbur

clang/docs/InternalsManual.rst

@@ -2859,67 +2859,6 @@ This library is called by the :ref:`Parser library <Parser>` during parsing to
 do semantic analysis of the input.  For valid programs, Sema builds an AST for
 parsed constructs.
 
-
-Concept Satisfaction Checking and Subsumption
----------------------------------------------
-
-As per the C++ standard, constraints are `normalized <https://eel.is/c++draft/temp.constr.normal>`_
-and the normal form is used both for subsumption, and constraint checking.
-Both depend on a parameter mapping that substitutes lazily. In particular,
-we should not substitute in unused arguments.
-
-Clang follows the order of operations prescribed by the standard.
-
-Normalization happens prior to satisfaction and subsumption
-and is handled by ``NormalizedConstraint``.
-
-Clang preserves in the normalized form intermediate concept-ids
-(``ConceptIdConstraint``) This is used for diagnostics only and no substitution
-happens in a ConceptIdConstraint if its expression is satisfied.
-
-The normal form of the associated constraints of a declaration is cached in
-Sema::NormalizationCache such that it is only computed once.
-
-A ``NormalizedConstraint`` is a recursive data structure, where each node
-contains a parameter mapping, represented by the indexes of all parameter
-being used.
-
-Checking satisfaction is done by ``ConstraintSatisfactionChecker``, recursively
-walking ``NormalizedConstraint``. At each level, we substitute the outermost
-level of the template arguments referenced in the parameter mapping of a
-normalized expression (``MultiLevelTemplateArgumentList``).
-
-For the following example,
-
-.. code-block:: c++
-
-  template <typename T>
-  concept A = __is_same(T, int);
-
-  template <typename U>
-  concept B = A<U> && __is_same(U, int);
-
-The normal form of B is
-
-.. code-block:: c++
-
-    __is_same(T, int) /*T->U, innermost level*/
- && __is_same(U, int) {U->U} /*T->U, outermost level*/
-
-After substitution in the mapping, we substitute in the constraint expression
-using that copy of the ``MultiLevelTemplateArgumentList``, and then evaluate it.
-
-Because this is expensive, it is cached in
-``UnsubstitutedConstraintSatisfactionCache``.
-
-Any error during satisfaction is recorded in ``ConstraintSatisfaction``.
-for nested requirements, ``ConstraintSatisfaction`` is stored (including
-diagnostics) in the AST, which is something we might want to improve.
-
-When an atomic constraint is not satified, we try to substitute into any
-enclosing concept-id using the same mechanism described above, for
-diagnostics purpose, and inject that in the ``ConstraintSatisfaction``.
-
 .. _CodeGen:
 
 The CodeGen Library

clang/docs/ReleaseNotes.rst

@@ -160,10 +160,6 @@ C++23 Feature Support
 C++20 Feature Support
 ^^^^^^^^^^^^^^^^^^^^^
 
-- Clang now normalizes constraints before checking whether they are satisfied, as mandated by the standard.
-  As a result, Clang no longer incorrectly diagnoses substitution failures in template arguments only
-  used in concept-ids, and produces better diagnostics for satisfaction failure. (#GH61811) (#GH135190)
-
 C++17 Feature Support
 ^^^^^^^^^^^^^^^^^^^^^
 
@@ -450,6 +446,7 @@ Bug Fixes to AST Handling
   legal representation. This is fixed because ElaboratedTypes don't exist anymore. (#GH43179) (#GH68670) (#GH92757)
 - Fix unrecognized html tag causing undesirable comment lexing (#GH152944)
 - Fix comment lexing of special command names (#GH152943)
+- Use `extern` as a hint to continue parsing when recovering from a malformed declaration.
 
 Miscellaneous Bug Fixes
 ^^^^^^^^^^^^^^^^^^^^^^^

clang/include/clang/AST/ASTConcept.h

@@ -28,20 +28,10 @@ namespace clang {
 
 class ConceptDecl;
 class TemplateDecl;
-class ConceptReference;
 class Expr;
 class NamedDecl;
 struct PrintingPolicy;
 
-/// Unsatisfied constraint expressions if the template arguments could be
-/// substituted into them, or a diagnostic if substitution resulted in
-/// an invalid expression.
-///
-using ConstraintSubstitutionDiagnostic = std::pair<SourceLocation, StringRef>;
-using UnsatisfiedConstraintRecord =
-    llvm::PointerUnion<const Expr *, const ConceptReference *,
-                       const ConstraintSubstitutionDiagnostic *>;
-
 /// The result of a constraint satisfaction check, containing the necessary
 /// information to diagnose an unsatisfied constraint.
 class ConstraintSatisfaction : public llvm::FoldingSetNode {
@@ -58,13 +48,16 @@ class ConstraintSatisfaction : public llvm::FoldingSetNode {
                          ArrayRef<TemplateArgument> TemplateArgs)
       : ConstraintOwner(ConstraintOwner), TemplateArgs(TemplateArgs) {}
 
+  using SubstitutionDiagnostic = std::pair<SourceLocation, StringRef>;
+  using Detail = llvm::PointerUnion<Expr *, SubstitutionDiagnostic *>;
+
   bool IsSatisfied = false;
   bool ContainsErrors = false;
 
   /// \brief The substituted constraint expr, if the template arguments could be
   /// substituted into them, or a diagnostic if substitution resulted in an
   /// invalid expression.
-  llvm::SmallVector<UnsatisfiedConstraintRecord, 4> Details;
+  llvm::SmallVector<Detail, 4> Details;
 
   void Profile(llvm::FoldingSetNodeID &ID, const ASTContext &C) {
     Profile(ID, C, ConstraintOwner, TemplateArgs);
@@ -76,12 +69,19 @@ class ConstraintSatisfaction : public llvm::FoldingSetNode {
 
   bool HasSubstitutionFailure() {
     for (const auto &Detail : Details)
-      if (Detail.dyn_cast<const ConstraintSubstitutionDiagnostic *>())
+      if (Detail.dyn_cast<SubstitutionDiagnostic *>())
         return true;
     return false;
   }
 };
 
+/// Pairs of unsatisfied atomic constraint expressions along with the
+/// substituted constraint expr, if the template arguments could be
+/// substituted into them, or a diagnostic if substitution resulted in
+/// an invalid expression.
+using UnsatisfiedConstraintRecord =
+    llvm::PointerUnion<Expr *, std::pair<SourceLocation, StringRef> *>;
+
 /// \brief The result of a constraint satisfaction check, containing the
 /// necessary information to diagnose an unsatisfied constraint.
 ///
@@ -101,10 +101,6 @@ struct ASTConstraintSatisfaction final :
     return getTrailingObjects() + NumRecords;
   }
 
-  ArrayRef<UnsatisfiedConstraintRecord> records() const {
-    return {begin(), end()};
-  }
-
   ASTConstraintSatisfaction(const ASTContext &C,
                             const ConstraintSatisfaction &Satisfaction);
   ASTConstraintSatisfaction(const ASTContext &C,
@@ -286,11 +282,6 @@ class TypeConstraint {
   }
 };
 
-/// Insertion operator for diagnostics.  This allows sending ConceptReferences's
-/// into a diagnostic with <<.
-const StreamingDiagnostic &operator<<(const StreamingDiagnostic &DB,
-                                      const ConceptReference *C);
-
 } // clang
 
 #endif // LLVM_CLANG_AST_ASTCONCEPT_H

clang/include/clang/AST/ASTContext.h

@@ -3877,6 +3877,7 @@ typename clang::LazyGenerationalUpdatePtr<Owner, T, Update>::ValueType
     return new (Ctx) LazyData(Source, Value);
   return Value;
 }
+
 template <> struct llvm::DenseMapInfo<llvm::FoldingSetNodeID> {
   static FoldingSetNodeID getEmptyKey() { return FoldingSetNodeID{}; }
 

clang/include/clang/Analysis/CFG.h

@@ -1251,6 +1251,7 @@ class CFG {
     bool MarkElidedCXXConstructors = false;
     bool AddVirtualBaseBranches = false;
     bool OmitImplicitValueInitializers = false;
+    bool AssumeReachableDefaultInSwitchStatements = false;
 
     BuildOptions() = default;
 

clang/include/clang/CIR/MissingFeatures.h

@@ -133,7 +133,6 @@ struct MissingFeatures {
   // RecordType
   static bool skippedLayout() { return false; }
   static bool astRecordDeclAttr() { return false; }
-  static bool recordZeroInit() { return false; }
   static bool recordZeroInitPadding() { return false; }
   static bool zeroSizeRecordMembers() { return false; }
 
@@ -192,6 +191,7 @@ struct MissingFeatures {
   static bool builtinCheckKind() { return false; }
   static bool cgCapturedStmtInfo() { return false; }
   static bool cgFPOptionsRAII() { return false; }
+  static bool checkBitfieldClipping() { return false; }
   static bool cirgenABIInfo() { return false; }
   static bool cleanupAfterErrorDiags() { return false; }
   static bool cleanupsToDeactivate() { return false; }