Merge branch 'main' into fix/125810

Author: a-tarasyuk

clang/docs/ReleaseNotes.rst

@@ -278,6 +278,8 @@ Improvements to Clang's diagnostics
 
 - Improve the diagnostics for shadows template parameter to report correct location (#GH129060).
 
+- Improve the ``-Wundefined-func-template`` warning when a function template is not instantiated due to being unreachable in modules.
+
 Improvements to Clang's time-trace
 ----------------------------------
 
@@ -340,6 +342,8 @@ Bug Fixes to C++ Support
 - Fixed an assertion failure affecting code that uses C++23 "deducing this". (#GH130272)
 - Clang now properly instantiates destructors for initialized members within non-delegating constructors. (#GH93251)
 - Correctly diagnoses if unresolved using declarations shadows template paramters (#GH129411)
+- Clang was previously coalescing volatile writes to members of volatile base class subobjects.
+  The issue has been addressed by propagating qualifiers during derived-to-base conversions in the AST. (#GH127824)
 - Clang now emits the ``-Wunused-variable`` warning when some structured bindings are unused
   and the ``[[maybe_unused]]`` attribute is not applied. (#GH125810)
 

clang/docs/analyzer/checkers.rst

@@ -543,6 +543,42 @@ Do not attempt to create a std::string from a null pointer
    }
  }
 
+.. _cplusplus-PureVirtualCall:
+
+cplusplus.PureVirtualCall (C++)
+"""""""""""""""""""""""""""""""
+
+When `virtual methods are called during construction and destruction
+<https://en.cppreference.com/w/cpp/language/virtual#During_construction_and_destruction>`__
+the polymorphism is restricted to the class that's being constructed or
+destructed because the more derived contexts are either not yet initialized or
+already destructed.
+
+This checker reports situations where this restricted polymorphism causes a
+call to a pure virtual method, which is undefined behavior. (See also the
+related checker :ref:`optin-cplusplus-VirtualCall` which reports situations
+where the restricted polymorphism affects a call and the called method is not
+pure virtual – but may be still surprising for the programmer.)
+
+.. code-block:: cpp
+
+ struct A {
+   virtual int getKind() = 0;
+
+   A() {
+     // warn: This calls the pure virtual method A::getKind().
+     log << "Constructing " << getKind();
+   }
+   virtual ~A() {
+     releaseResources();
+   }
+   void releaseResources() {
+     // warn: This can call the pure virtual method A::getKind() when this is
+     // called from the destructor.
+     callSomeFunction(getKind())
+   }
+ };
+
 .. _deadcode-checkers:
 
 deadcode
@@ -833,24 +869,40 @@ This checker has several options which can be set from command line (e.g.
 
 optin.cplusplus.VirtualCall (C++)
 """""""""""""""""""""""""""""""""
-Check virtual function calls during construction or destruction.
+
+When `virtual methods are called during construction and destruction
+<https://en.cppreference.com/w/cpp/language/virtual#During_construction_and_destruction>`__
+the polymorphism is restricted to the class that's being constructed or
+destructed because the more derived contexts are either not yet initialized or
+already destructed.
+
+Although this behavior is well-defined, it can surprise the programmer and
+cause unintended behavior, so this checker reports calls that appear to be
+virtual calls but can be affected by this restricted polymorphism.
+
+Note that situations where this restricted polymorphism causes a call to a pure
+virtual method (which is definitely invalid, triggers undefined behavior) are
+**reported by another checker:** :ref:`cplusplus-PureVirtualCall` and **this
+checker does not report them**.
 
 .. code-block:: cpp
 
- class A {
- public:
+ struct A {
+   virtual int getKind();
+
    A() {
-     f(); // warn
+     // warn: This calls A::getKind() even if we are constructing an instance
+     // of a different class that is derived from A.
+     log << "Constructing " << getKind();
    }
-   virtual void f();
- };
-
- class A {
- public:
-   ~A() {
-     this->f(); // warn
+   virtual ~A() {
+     releaseResources();
+   }
+   void releaseResources() {
+     // warn: This can be called within ~A() and calls A::getKind() even if
+     // we are destructing a class that is derived from A.
+     callSomeFunction(getKind())
    }
-   virtual void f();
  };
 
 .. _optin-mpi-MPI-Checker:

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -5700,6 +5700,8 @@ def warn_func_template_missing : Warning<"instantiation of function %q0 "
   InGroup<UndefinedFuncTemplate>, DefaultIgnore;
 def note_forward_template_decl : Note<
   "forward declaration of template entity is here">;
+def note_unreachable_template_decl
+    : Note<"unreachable declaration of template entity is here">;
 def note_inst_declaration_hint : Note<"add an explicit instantiation "
   "declaration to suppress this warning if %q0 is explicitly instantiated in "
   "another translation unit">;

clang/include/clang/Driver/OffloadBundler.h

@@ -107,50 +107,20 @@ struct OffloadTargetInfo {
 // - Compressed Data (variable length).
 class CompressedOffloadBundle {
 private:
-  static inline const size_t MagicSize = 4;
-  static inline const size_t VersionFieldSize = sizeof(uint16_t);
-  static inline const size_t MethodFieldSize = sizeof(uint16_t);
-  // Legacy size fields for V1/V2
-  static inline const size_t FileSizeFieldSizeV2 = sizeof(uint32_t);
-  static inline const size_t UncompressedSizeFieldSizeV2 = sizeof(uint32_t);
-  // New size fields for V3
-  static inline const size_t FileSizeFieldSizeV3 = sizeof(uint64_t);
-  static inline const size_t UncompressedSizeFieldSizeV3 = sizeof(uint64_t);
-  static inline const size_t HashFieldSize = sizeof(uint64_t);
-
-  // Keep V1 header size for backward compatibility
-  static inline const size_t V1HeaderSize =
-      MagicSize + VersionFieldSize + MethodFieldSize +
-      UncompressedSizeFieldSizeV2 + HashFieldSize;
-
-  // Keep V2 header size for backward compatibility
-  static inline const size_t V2HeaderSize =
-      MagicSize + VersionFieldSize + FileSizeFieldSizeV2 + MethodFieldSize +
-      UncompressedSizeFieldSizeV2 + HashFieldSize;
-
-  // Add V3 header size with 64-bit fields
-  static inline const size_t V3HeaderSize =
-      MagicSize + VersionFieldSize + FileSizeFieldSizeV3 + MethodFieldSize +
-      UncompressedSizeFieldSizeV3 + HashFieldSize;
-
   static inline const llvm::StringRef MagicNumber = "CCOB";
 
 public:
-  static inline const uint16_t DefaultVersion = 2;
+  struct CompressedBundleHeader {
+    unsigned Version;
+    llvm::compression::Format CompressionFormat;
+    std::optional<size_t> FileSize;
+    size_t UncompressedFileSize;
+    uint64_t Hash;
 
-  // Helper method to get header size based on version
-  static size_t getHeaderSize(uint16_t Version) {
-    switch (Version) {
-    case 1:
-      return V1HeaderSize;
-    case 2:
-      return V2HeaderSize;
-    case 3:
-      return V3HeaderSize;
-    default:
-      llvm_unreachable("Unsupported version");
-    }
-  }
+    static llvm::Expected<CompressedBundleHeader> tryParse(llvm::StringRef);
+  };
+
+  static inline const uint16_t DefaultVersion = 2;
 
   static llvm::Expected<std::unique_ptr<llvm::MemoryBuffer>>
   compress(llvm::compression::Params P, const llvm::MemoryBuffer &Input,

clang/include/clang/Sema/Sema.h

@@ -11268,13 +11268,11 @@ class Sema final : public SemaBase {
 
   /// Determine whether we would be unable to instantiate this template (because
   /// it either has no definition, or is in the process of being instantiated).
-  bool DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
-                                      NamedDecl *Instantiation,
-                                      bool InstantiatedFromMember,
-                                      const NamedDecl *Pattern,
-                                      const NamedDecl *PatternDef,
-                                      TemplateSpecializationKind TSK,
-                                      bool Complain = true);
+  bool DiagnoseUninstantiableTemplate(
+      SourceLocation PointOfInstantiation, NamedDecl *Instantiation,
+      bool InstantiatedFromMember, const NamedDecl *Pattern,
+      const NamedDecl *PatternDef, TemplateSpecializationKind TSK,
+      bool Complain = true, bool *Unreachable = nullptr);
 
   /// DiagnoseTemplateParameterShadow - Produce a diagnostic complaining
   /// that the template parameter 'PrevDecl' is being shadowed by a new

clang/lib/CodeGen/CGExprComplex.cpp

@@ -286,8 +286,7 @@ class ComplexExprEmitter
   ComplexPairTy EmitComplexBinOpLibCall(StringRef LibCallName,
                                         const BinOpInfo &Op);
 
-  QualType HigherPrecisionTypeForComplexArithmetic(QualType ElementType,
-                                                   bool IsDivOpCode) {
+  QualType HigherPrecisionTypeForComplexArithmetic(QualType ElementType) {
     ASTContext &Ctx = CGF.getContext();
     const QualType HigherElementType =
         Ctx.GetHigherPrecisionFPType(ElementType);
@@ -314,7 +313,7 @@ class ComplexExprEmitter
   }
 
   QualType getPromotionType(FPOptionsOverride Features, QualType Ty,
-                            bool IsDivOpCode = false) {
+                            bool IsComplexDivisor) {
     if (auto *CT = Ty->getAs<ComplexType>()) {
       QualType ElementType = CT->getElementType();
       bool IsFloatingType = ElementType->isFloatingType();
@@ -325,10 +324,9 @@ class ComplexExprEmitter
                                      Features.getComplexRangeOverride() ==
                                          CGF.getLangOpts().getComplexRange();
 
-      if (IsDivOpCode && IsFloatingType && IsComplexRangePromoted &&
+      if (IsComplexDivisor && IsFloatingType && IsComplexRangePromoted &&
           (HasNoComplexRangeOverride || HasMatchingComplexRange))
-        return HigherPrecisionTypeForComplexArithmetic(ElementType,
-                                                       IsDivOpCode);
+        return HigherPrecisionTypeForComplexArithmetic(ElementType);
       if (ElementType.UseExcessPrecision(CGF.getContext()))
         return CGF.getContext().getComplexType(CGF.getContext().FloatTy);
     }
@@ -339,9 +337,10 @@ class ComplexExprEmitter
 
 #define HANDLEBINOP(OP)                                                        \
   ComplexPairTy VisitBin##OP(const BinaryOperator *E) {                        \
-    QualType promotionTy = getPromotionType(                                   \
-        E->getStoredFPFeaturesOrDefault(), E->getType(),                       \
-        (E->getOpcode() == BinaryOperatorKind::BO_Div) ? true : false);        \
+    QualType promotionTy =                                                     \
+        getPromotionType(E->getStoredFPFeaturesOrDefault(), E->getType(),      \
+                         (E->getOpcode() == BinaryOperatorKind::BO_Div &&      \
+                          E->getRHS()->getType()->isAnyComplexType()));        \
     ComplexPairTy result = EmitBin##OP(EmitBinOps(E, promotionTy));            \
     if (!promotionTy.isNull())                                                 \
       result = CGF.EmitUnPromotedValue(result, E->getType());                  \
@@ -639,7 +638,8 @@ ComplexPairTy ComplexExprEmitter::VisitUnaryPlus(const UnaryOperator *E,
   QualType promotionTy =
       PromotionType.isNull()
           ? getPromotionType(E->getStoredFPFeaturesOrDefault(),
-                             E->getSubExpr()->getType())
+                             E->getSubExpr()->getType(),
+                             /*IsComplexDivisor=*/false)
           : PromotionType;
   ComplexPairTy result = VisitPlus(E, promotionTy);
   if (!promotionTy.isNull())
@@ -661,7 +661,8 @@ ComplexPairTy ComplexExprEmitter::VisitUnaryMinus(const UnaryOperator *E,
   QualType promotionTy =
       PromotionType.isNull()
           ? getPromotionType(E->getStoredFPFeaturesOrDefault(),
-                             E->getSubExpr()->getType())
+                             E->getSubExpr()->getType(),
+                             /*IsComplexDivisor=*/false)
           : PromotionType;
   ComplexPairTy result = VisitMinus(E, promotionTy);
   if (!promotionTy.isNull())
@@ -1213,19 +1214,24 @@ EmitCompoundAssignLValue(const CompoundAssignOperator *E,
   OpInfo.FPFeatures = E->getFPFeaturesInEffect(CGF.getLangOpts());
   CodeGenFunction::CGFPOptionsRAII FPOptsRAII(CGF, OpInfo.FPFeatures);
 
+  const bool IsComplexDivisor = E->getOpcode() == BO_DivAssign &&
+                                E->getRHS()->getType()->isAnyComplexType();
+
   // Load the RHS and LHS operands.
   // __block variables need to have the rhs evaluated first, plus this should
   // improve codegen a little.
   QualType PromotionTypeCR;
-  PromotionTypeCR = getPromotionType(E->getStoredFPFeaturesOrDefault(),
-                                     E->getComputationResultType());
+  PromotionTypeCR =
+      getPromotionType(E->getStoredFPFeaturesOrDefault(),
+                       E->getComputationResultType(), IsComplexDivisor);
   if (PromotionTypeCR.isNull())
     PromotionTypeCR = E->getComputationResultType();
   OpInfo.Ty = PromotionTypeCR;
   QualType ComplexElementTy =
       OpInfo.Ty->castAs<ComplexType>()->getElementType();
-  QualType PromotionTypeRHS = getPromotionType(
-      E->getStoredFPFeaturesOrDefault(), E->getRHS()->getType());
+  QualType PromotionTypeRHS =
+      getPromotionType(E->getStoredFPFeaturesOrDefault(),
+                       E->getRHS()->getType(), IsComplexDivisor);
 
   // The RHS should have been converted to the computation type.
   if (E->getRHS()->getType()->isRealFloatingType()) {
@@ -1253,8 +1259,9 @@ EmitCompoundAssignLValue(const CompoundAssignOperator *E,
 
   // Load from the l-value and convert it.
   SourceLocation Loc = E->getExprLoc();
-  QualType PromotionTypeLHS = getPromotionType(
-      E->getStoredFPFeaturesOrDefault(), E->getComputationLHSType());
+  QualType PromotionTypeLHS =
+      getPromotionType(E->getStoredFPFeaturesOrDefault(),
+                       E->getComputationLHSType(), IsComplexDivisor);
   if (LHSTy->isAnyComplexType()) {
     ComplexPairTy LHSVal = EmitLoadOfLValue(LHS, Loc);
     if (!PromotionTypeLHS.isNull())