Merged main:57907c1a96e8 into amd-gfx:4746962a0740

Local branch amd-gfx 4746962 Merged main:7907292daa78 into amd-gfx:006dcb723c69
Remote branch main 57907c1 [clang-tidy] ignore `[[clang::lifetimebound]]` param in return-const-ref-from-parameter (llvm#118315)

Author: SC llvm team

.github/CODEOWNERS

@@ -7,10 +7,9 @@
 # to receive an approval from a "code owner" in particular -- any LLVM project
 # member can approve pull requests.
 #
-# Note that GitHub's concept of "code owner" is independent from LLVM's own
-# "code owner" concept, they merely happen to share terminology. See
-# https://llvm.org/docs/DeveloperPolicy.html#code-owners, as well as the
-# CODE_OWNERS.txt files in the respective subproject directories.
+# This is independent of LLVM's own "maintainer" concept.
+# See https://llvm.org/docs/DeveloperPolicy.html#maintainers as well as the
+# Maintainers.* files in the the respective subproject directories.
 
 /libcxx/ @llvm/reviewers-libcxx
 /libcxxabi/ @llvm/reviewers-libcxxabi

clang-tools-extra/clang-tidy/bugprone/ReturnConstRefFromParameterCheck.cpp

@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "ReturnConstRefFromParameterCheck.h"
+#include "clang/AST/Attrs.inc"
 #include "clang/AST/Expr.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/ASTMatchers/ASTMatchers.h"
@@ -15,14 +16,23 @@ using namespace clang::ast_matchers;
 
 namespace clang::tidy::bugprone {
 
+namespace {
+
+AST_MATCHER(ParmVarDecl, hasLifetimeBoundAttr) {
+  return Node.hasAttr<LifetimeBoundAttr>();
+}
+
+} // namespace
+
 void ReturnConstRefFromParameterCheck::registerMatchers(MatchFinder *Finder) {
   const auto DRef = ignoringParens(
       declRefExpr(
           to(parmVarDecl(hasType(hasCanonicalType(
                              qualType(lValueReferenceType(pointee(
                                           qualType(isConstQualified()))))
                                  .bind("type"))),
-                         hasDeclContext(functionDecl().bind("owner")))
+                         hasDeclContext(functionDecl().bind("owner")),
+                         unless(hasLifetimeBoundAttr()))
                  .bind("param")))
           .bind("dref"));
   const auto Func =

clang-tools-extra/docs/ReleaseNotes.rst

@@ -184,7 +184,8 @@ Changes in existing checks
   <clang-tidy/checks/bugprone/return-const-ref-from-parameter>` check to
   diagnose potential dangling references when returning a ``const &`` parameter
   by using the conditional operator ``cond ? var1 : var2`` and no longer giving
-  false positives for functions which contain lambda.
+  false positives for functions which contain lambda and ignore parameters
+  with ``[[clang::lifetimebound]]`` attribute.
 
 - Improved :doc:`bugprone-sizeof-expression
   <clang-tidy/checks/bugprone/sizeof-expression>` check to find suspicious

clang-tools-extra/docs/clang-tidy/checks/bugprone/return-const-ref-from-parameter.rst

@@ -12,15 +12,6 @@ after the call. When the function returns such a parameter also as constant refe
 then the returned reference can be used after the object it refers to has been
 destroyed.
 
-This issue can be resolved by declaring an overload of the problematic function
-where the ``const &`` parameter is instead declared as ``&&``. The developer has
-to ensure that the implementation of that function does not produce a
-use-after-free, the exact error that this check is warning against.
-Marking such an ``&&`` overload as ``deleted``, will silence the warning as 
-well. In the case of different ``const &`` parameters being returned depending
-on the control flow of the function, an overload where all problematic
-``const &`` parameters have been declared as ``&&`` will resolve the issue.
-
 Example
 -------
 
@@ -38,3 +29,23 @@ Example
 
   const S& s = fn(S{1});
   s.v; // use after free
+
+
+This issue can be resolved by declaring an overload of the problematic function
+where the ``const &`` parameter is instead declared as ``&&``. The developer has
+to ensure that the implementation of that function does not produce a
+use-after-free, the exact error that this check is warning against.
+Marking such an ``&&`` overload as ``deleted``, will silence the warning as 
+well. In the case of different ``const &`` parameters being returned depending
+on the control flow of the function, an overload where all problematic
+``const &`` parameters have been declared as ``&&`` will resolve the issue.
+
+This issue can also be resolved by adding ``[[clang::lifetimebound]]``. Clang
+enable ``-Wdangling`` warning by default which can detect mis-uses of the
+annotated function. See `lifetimebound attribute <https://clang.llvm.org/docs/AttributeReference.html#id11>`_
+for details.
+
+.. code-block:: c++
+
+  const int &f(const int &a [[clang::lifetimebound]]) { return a; } // no warning
+  const int &v = f(1); // warning: temporary bound to local reference 'v' will be destroyed at the end of the full-expression [-Wdangling]

clang-tools-extra/test/clang-tidy/checkers/bugprone/return-const-ref-from-parameter.cpp

@@ -197,3 +197,9 @@ int const &overload_params_difference3(int p1, int const &a, int p2) { return a;
 int const &overload_params_difference3(int p1, long &&a, int p2);
 
 } // namespace overload
+
+namespace gh117696 {
+namespace use_lifetime_bound_attr {
+int const &f(int const &a [[clang::lifetimebound]]) { return a; }
+} // namespace use_lifetime_bound_attr
+} // namespace gh117696

clang/docs/LanguageExtensions.rst

@@ -648,7 +648,7 @@ elementwise to the input.
 Unless specified otherwise operation(±0) = ±0 and operation(±infinity) = ±infinity
 
 The integer elementwise intrinsics, including ``__builtin_elementwise_popcount``,
-can be called in a ``constexpr`` context.
+``__builtin_elementwise_bitreverse``, can be called in a ``constexpr`` context.
 
 ============================================== ====================================================================== =========================================
          Name                                   Operation                                                             Supported element types

clang/docs/ReleaseNotes.rst

@@ -310,6 +310,9 @@ Resolutions to C++ Defect Reports
   by default.
   (`CWG2521: User-defined literals and reserved identifiers <https://cplusplus.github.io/CWG/issues/2521.html>`_).
 
+- Fix name lookup for a dependent base class that is the current instantiation.  
+  (`CWG591: When a dependent base class is the current instantiation <https://cplusplus.github.io/CWG/issues/591.html>`_).
+
 C Language Changes
 ------------------
 
@@ -404,6 +407,7 @@ Non-comprehensive list of changes in this release
 - ``__builtin_reduce_and`` function can now be used in constant expressions.
 - ``__builtin_reduce_or`` and ``__builtin_reduce_xor`` functions can now be used in constant expressions.
 - ``__builtin_elementwise_popcount`` function can now be used in constant expressions.
+- ``__builtin_elementwise_bitreverse`` function can now be used in constant expressions.
 
 New Compiler Flags
 ------------------
@@ -763,6 +767,8 @@ Bug Fixes to C++ Support
 - Fixed an assertion failure caused by using ``consteval`` in condition in consumed analyses. (#GH117385)
 - Fix a crash caused by incorrect argument position in merging deduced template arguments. (#GH113659)
 - Fixed an assertion failure caused by mangled names with invalid identifiers. (#GH112205)
+- Fixed an incorrect lambda scope of generic lambdas that caused Clang to crash when computing potential lambda
+  captures at the end of a full expression. (#GH115931)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^

clang/include/clang/Basic/Builtins.td

@@ -1270,7 +1270,7 @@ def ElementwiseATan2 : Builtin {
 
 def ElementwiseBitreverse : Builtin {
   let Spellings = ["__builtin_elementwise_bitreverse"];
-  let Attributes = [NoThrow, Const, CustomTypeChecking];
+  let Attributes = [NoThrow, Const, CustomTypeChecking, Constexpr];
   let Prototype = "void(...)";
 }
 
@@ -4930,6 +4930,12 @@ def HLSLClip: LangBuiltin<"HLSL_LANG"> {
   let Prototype = "void(...)";
 }
 
+def HLSLGroupMemoryBarrierWithGroupSync: LangBuiltin<"HLSL_LANG"> {
+  let Spellings = ["__builtin_hlsl_group_memory_barrier_with_group_sync"];
+  let Attributes = [NoThrow, Const];
+  let Prototype = "void()";
+}
+
 // Builtins for XRay.
 def XRayCustomEvent : Builtin {
   let Spellings = ["__xray_customevent"];

clang/lib/AST/ByteCode/Compiler.cpp

@@ -1000,7 +1000,10 @@ bool Compiler<Emitter>::VisitPointerArithBinOp(const BinaryOperator *E) {
     if (!visitAsPointer(RHS, *RT) || !visitAsPointer(LHS, *LT))
       return false;
 
-    return this->emitSubPtr(classifyPrim(E->getType()), E);
+    PrimType IntT = classifyPrim(E->getType());
+    if (!this->emitSubPtr(IntT, E))
+      return false;
+    return DiscardResult ? this->emitPop(IntT, E) : true;
   }
 
   PrimType OffsetType;
@@ -5911,6 +5914,9 @@ bool Compiler<Emitter>::VisitVectorUnaryOperator(const UnaryOperator *E) {
     return this->discard(SubExpr);
 
   auto UnaryOp = E->getOpcode();
+  if (UnaryOp == UO_Extension)
+    return this->delegate(SubExpr);
+
   if (UnaryOp != UO_Plus && UnaryOp != UO_Minus && UnaryOp != UO_LNot &&
       UnaryOp != UO_Not && UnaryOp != UO_AddrOf)
     return this->emitInvalid(E);

clang/lib/AST/ByteCode/InterpBuiltin.cpp

@@ -148,6 +148,17 @@ static bool retPrimValue(InterpState &S, CodePtr OpPC,
 #undef RET_CASE
 }
 
+static void diagnoseNonConstexprBuiltin(InterpState &S, CodePtr OpPC,
+                                        unsigned ID) {
+  auto Loc = S.Current->getSource(OpPC);
+  if (S.getLangOpts().CPlusPlus11)
+    S.CCEDiag(Loc, diag::note_constexpr_invalid_function)
+        << /*isConstexpr=*/0 << /*isConstructor=*/0
+        << ("'" + S.getASTContext().BuiltinInfo.getName(ID) + "'").str();
+  else
+    S.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr);
+}
+
 static bool interp__builtin_is_constant_evaluated(InterpState &S, CodePtr OpPC,
                                                   const InterpFrame *Frame,
                                                   const CallExpr *Call) {
@@ -181,10 +192,14 @@ static bool interp__builtin_is_constant_evaluated(InterpState &S, CodePtr OpPC,
 
 static bool interp__builtin_strcmp(InterpState &S, CodePtr OpPC,
                                    const InterpFrame *Frame,
-                                   const CallExpr *Call) {
+                                   const Function *Func, const CallExpr *Call) {
+  unsigned ID = Func->getBuiltinID();
   const Pointer &A = getParam<Pointer>(Frame, 0);
   const Pointer &B = getParam<Pointer>(Frame, 1);
 
+  if (ID == Builtin::BIstrcmp)
+    diagnoseNonConstexprBuiltin(S, OpPC, ID);
+
   if (!CheckLive(S, OpPC, A, AK_Read) || !CheckLive(S, OpPC, B, AK_Read))
     return false;
 
@@ -224,9 +239,13 @@ static bool interp__builtin_strcmp(InterpState &S, CodePtr OpPC,
 
 static bool interp__builtin_strlen(InterpState &S, CodePtr OpPC,
                                    const InterpFrame *Frame,
-                                   const CallExpr *Call) {
+                                   const Function *Func, const CallExpr *Call) {
+  unsigned ID = Func->getBuiltinID();
   const Pointer &StrPtr = getParam<Pointer>(Frame, 0);
 
+  if (ID == Builtin::BIstrlen)
+    diagnoseNonConstexprBuiltin(S, OpPC, ID);
+
   if (!CheckArray(S, OpPC, StrPtr))
     return false;
 
@@ -1772,6 +1791,7 @@ static bool interp__builtin_elementwise_popcount(InterpState &S, CodePtr OpPC,
     INT_TYPE_SWITCH_NO_BOOL(ElemT, {
       Dst.atIndex(I).deref<T>() =
           T::from(Arg.atIndex(I).deref<T>().toAPSInt().popcount());
+      Dst.atIndex(I).initialize();
     });
   }
 
@@ -1781,21 +1801,36 @@ static bool interp__builtin_memcpy(InterpState &S, CodePtr OpPC,
                                    const InterpFrame *Frame,
                                    const Function *Func, const CallExpr *Call) {
   assert(Call->getNumArgs() == 3);
+  unsigned ID = Func->getBuiltinID();
   Pointer DestPtr = getParam<Pointer>(Frame, 0);
   const Pointer &SrcPtr = getParam<Pointer>(Frame, 1);
   const APSInt &Size =
       peekToAPSInt(S.Stk, *S.getContext().classify(Call->getArg(2)));
   assert(!Size.isSigned() && "memcpy and friends take an unsigned size");
 
-  if (DestPtr.isDummy() || SrcPtr.isDummy())
-    return false;
+  if (ID == Builtin::BImemcpy || ID == Builtin::BImemmove)
+    diagnoseNonConstexprBuiltin(S, OpPC, ID);
+
+  bool Move = (ID == Builtin::BI__builtin_memmove || ID == Builtin::BImemmove);
 
   // If the size is zero, we treat this as always being a valid no-op.
   if (Size.isZero()) {
     S.Stk.push<Pointer>(DestPtr);
     return true;
   }
 
+  if (SrcPtr.isZero() || DestPtr.isZero()) {
+    Pointer DiagPtr = (SrcPtr.isZero() ? SrcPtr : DestPtr);
+    S.FFDiag(S.Current->getSource(OpPC), diag::note_constexpr_memcpy_null)
+        << /*IsMove=*/Move << /*IsWchar=*/false << !SrcPtr.isZero()
+        << DiagPtr.toDiagnosticString(S.getASTContext());
+    return false;
+  }
+
+  // As a last resort, reject dummy pointers.
+  if (DestPtr.isDummy() || SrcPtr.isDummy())
+    return false;
+
   if (!DoBitCastPtr(S, OpPC, SrcPtr, DestPtr))
     return false;
 
@@ -1818,11 +1853,13 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const Function *F,
   case Builtin::BI__assume:
     break;
   case Builtin::BI__builtin_strcmp:
-    if (!interp__builtin_strcmp(S, OpPC, Frame, Call))
+  case Builtin::BIstrcmp:
+    if (!interp__builtin_strcmp(S, OpPC, Frame, F, Call))
       return false;
     break;
   case Builtin::BI__builtin_strlen:
-    if (!interp__builtin_strlen(S, OpPC, Frame, Call))
+  case Builtin::BIstrlen:
+    if (!interp__builtin_strlen(S, OpPC, Frame, F, Call))
       return false;
     break;
   case Builtin::BI__builtin_nan:
@@ -2263,6 +2300,9 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const Function *F,
     break;
 
   case Builtin::BI__builtin_memcpy:
+  case Builtin::BImemcpy:
+  case Builtin::BI__builtin_memmove:
+  case Builtin::BImemmove:
     if (!interp__builtin_memcpy(S, OpPC, Frame, F, Call))
       return false;
     break;

clang/lib/AST/CXXInheritance.cpp

@@ -134,7 +134,7 @@ bool CXXRecordDecl::forallBases(ForallBasesCallback BaseMatches) const {
         return false;
 
       CXXRecordDecl *Base =
-            cast_or_null<CXXRecordDecl>(Ty->getDecl()->getDefinition());
+          cast_if_present<CXXRecordDecl>(Ty->getDecl()->getDefinition());
       if (!Base ||
           (Base->isDependentContext() &&
            !Base->isCurrentInstantiation(Record))) {
@@ -169,13 +169,21 @@ bool CXXBasePaths::lookupInBases(ASTContext &Context,
     QualType BaseType =
         Context.getCanonicalType(BaseSpec.getType()).getUnqualifiedType();
 
+    bool isCurrentInstantiation = isa<InjectedClassNameType>(BaseType);
+    if (!isCurrentInstantiation) {
+      if (auto *BaseRecord = cast_if_present<CXXRecordDecl>(
+              BaseSpec.getType()->getAsRecordDecl()))
+        isCurrentInstantiation = BaseRecord->isDependentContext() &&
+                                 BaseRecord->isCurrentInstantiation(Record);
+    }
     // C++ [temp.dep]p3:
     //   In the definition of a class template or a member of a class template,
     //   if a base class of the class template depends on a template-parameter,
     //   the base class scope is not examined during unqualified name lookup
     //   either at the point of definition of the class template or member or
     //   during an instantiation of the class tem- plate or member.
-    if (!LookupInDependent && BaseType->isDependentType())
+    if (!LookupInDependent &&
+        (BaseType->isDependentType() && !isCurrentInstantiation))
       continue;
 
     // Determine whether we need to visit this base class at all,
@@ -243,9 +251,8 @@ bool CXXBasePaths::lookupInBases(ASTContext &Context,
         return FoundPath;
       }
     } else if (VisitBase) {
-      CXXRecordDecl *BaseRecord;
+      CXXRecordDecl *BaseRecord = nullptr;
       if (LookupInDependent) {
-        BaseRecord = nullptr;
         const TemplateSpecializationType *TST =
             BaseSpec.getType()->getAs<TemplateSpecializationType>();
         if (!TST) {
@@ -264,8 +271,7 @@ bool CXXBasePaths::lookupInBases(ASTContext &Context,
             BaseRecord = nullptr;
         }
       } else {
-        BaseRecord = cast<CXXRecordDecl>(
-            BaseSpec.getType()->castAs<RecordType>()->getDecl());
+        BaseRecord = cast<CXXRecordDecl>(BaseSpec.getType()->getAsRecordDecl());
       }
       if (BaseRecord &&
           lookupInBases(Context, BaseRecord, BaseMatches, LookupInDependent)) {

clang/lib/AST/DeclCXX.cpp

@@ -2602,8 +2602,6 @@ bool CXXMethodDecl::isMoveAssignmentOperator() const {
 
 void CXXMethodDecl::addOverriddenMethod(const CXXMethodDecl *MD) {
   assert(MD->isCanonicalDecl() && "Method is not canonical!");
-  assert(!MD->getParent()->isDependentContext() &&
-         "Can't add an overridden method to a class template!");
   assert(MD->isVirtual() && "Method is not virtual!");
 
   getASTContext().addOverriddenMethod(this, MD);