1 files changed, 82 insertions, 24 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 4ffce2c12366..562c98c6babe 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -3352,6 +3352,7 @@ ExprResult Sema::BuildDeclarationNameExpr(
   case Decl::VarTemplateSpecialization:
   case Decl::VarTemplatePartialSpecialization:
   case Decl::Decomposition:
+  case Decl::Binding:
   case Decl::OMPCapturedExpr:
     // In C, "extern void blah;" is valid and is an r-value.
     if (!getLangOpts().CPlusPlus && !type.hasQualifiers() &&
@@ -3371,20 +3372,13 @@ ExprResult Sema::BuildDeclarationNameExpr(
     // potentially-evaluated contexts? Since the variable isn't actually
     // captured in an unevaluated context, it seems that the answer is no.
     if (!isUnevaluatedContext()) {
-      QualType CapturedType = getCapturedDeclRefType(cast<VarDecl>(VD), Loc);
+      QualType CapturedType = getCapturedDeclRefType(cast<ValueDecl>(VD), Loc);
       if (!CapturedType.isNull())
         type = CapturedType;
     }
-
     break;
   }
 
-  case Decl::Binding:
-    // These are always lvalues.
-    valueKind = VK_LValue;
-    type = type.getNonReferenceType();
-    break;
-
   case Decl::Function: {
     if (unsigned BID = cast<FunctionDecl>(VD)->getBuiltinID()) {
       if (!Context.BuiltinInfo.isDirectlyAddressable(BID)) {
@@ -5587,10 +5581,6 @@ static FieldDecl *FindFieldDeclInstantiationPattern(const ASTContext &Ctx,
 ExprResult Sema::BuildCXXDefaultInitExpr(SourceLocation Loc, FieldDecl *Field) {
   assert(Field->hasInClassInitializer());
 
-  // If we might have already tried and failed to instantiate, don't try again.
-  if (Field->isInvalidDecl())
-    return ExprError();
-
   CXXThisScopeRAII This(*this, Field->getParent(), Qualifiers());
 
   auto *ParentRD = cast<CXXRecordDecl>(Field->getParent());
@@ -5948,7 +5938,7 @@ Sema::ConvertArgumentsForCall(CallExpr *Call, Expr *Fn,
   SmallVector<Expr *, 8> AllArgs;
   VariadicCallType CallType = getVariadicCallType(FDecl, Proto, Fn);
 
-  Invalid = GatherArgumentsForCall(Call->getBeginLoc(), FDecl, Proto, 0, Args,
+  Invalid = GatherArgumentsForCall(Call->getExprLoc(), FDecl, Proto, 0, Args,
                                    AllArgs, CallType);
   if (Invalid)
     return true;
@@ -11790,6 +11780,51 @@ static bool checkForArray(const Expr *E) {
   return D->getType()->isArrayType() && !D->isWeak();
 }
 
+/// Detect patterns ptr + size >= ptr and ptr + size < ptr, where ptr is a
+/// pointer and size is an unsigned integer. Return whether the result is
+/// always true/false.
+static std::optional<bool> isTautologicalBoundsCheck(Sema &S, const Expr *LHS,
+                                                     const Expr *RHS,
+                                                     BinaryOperatorKind Opc) {
+  if (!LHS->getType()->isPointerType() ||
+      S.getLangOpts().isSignedOverflowDefined())
+    return std::nullopt;
+
+  // Canonicalize to >= or < predicate.
+  switch (Opc) {
+  case BO_GE:
+  case BO_LT:
+    break;
+  case BO_GT:
+    std::swap(LHS, RHS);
+    Opc = BO_LT;
+    break;
+  case BO_LE:
+    std::swap(LHS, RHS);
+    Opc = BO_GE;
+    break;
+  default:
+    return std::nullopt;
+  }
+
+  auto *BO = dyn_cast<BinaryOperator>(LHS);
+  if (!BO || BO->getOpcode() != BO_Add)
+    return std::nullopt;
+
+  Expr *Other;
+  if (Expr::isSameComparisonOperand(BO->getLHS(), RHS))
+    Other = BO->getRHS();
+  else if (Expr::isSameComparisonOperand(BO->getRHS(), RHS))
+    Other = BO->getLHS();
+  else
+    return std::nullopt;
+
+  if (!Other->getType()->isUnsignedIntegerType())
+    return std::nullopt;
+
+  return Opc == BO_GE;
+}
+
 /// Diagnose some forms of syntactically-obvious tautological comparison.
 static void diagnoseTautologicalComparison(Sema &S, SourceLocation Loc,
                                            Expr *LHS, Expr *RHS,
@@ -11843,7 +11878,9 @@ static void diagnoseTautologicalComparison(Sema &S, SourceLocation Loc,
       RHSStripped->getType()->isArrayType()) {
     auto IsDeprArrayComparionIgnored =
         S.getDiagnostics().isIgnored(diag::warn_depr_array_comparison, Loc);
-    auto DiagID = !S.getLangOpts().CPlusPlus20 || IsDeprArrayComparionIgnored
+    auto DiagID = S.getLangOpts().CPlusPlus26
+                      ? diag::warn_array_comparison_cxx26
+                  : !S.getLangOpts().CPlusPlus20 || IsDeprArrayComparionIgnored
                       ? diag::warn_array_comparison
                       : diag::warn_depr_array_comparison;
     S.Diag(Loc, DiagID) << LHS->getSourceRange() << RHS->getSourceRange()
@@ -11897,6 +11934,12 @@ static void diagnoseTautologicalComparison(Sema &S, SourceLocation Loc,
                             S.PDiag(diag::warn_comparison_always)
                                 << 1 /*array comparison*/
                                 << Result);
+    } else if (std::optional<bool> Res =
+                   isTautologicalBoundsCheck(S, LHS, RHS, Opc)) {
+      S.DiagRuntimeBehavior(Loc, nullptr,
+                            S.PDiag(diag::warn_comparison_always)
+                                << 2 /*pointer comparison*/
+                                << (*Res ? AlwaysTrue : AlwaysFalse));
     }
   }
 
@@ -13248,11 +13291,24 @@ static NonConstCaptureKind isReferenceToNonConstCapture(Sema &S, Expr *E) {
   if (!DRE) return NCCK_None;
   if (!DRE->refersToEnclosingVariableOrCapture()) return NCCK_None;
 
-  // The declaration must be a variable which is not declared 'const'.
-  VarDecl *var = dyn_cast<VarDecl>(DRE->getDecl());
-  if (!var) return NCCK_None;
-  if (var->getType().isConstQualified()) return NCCK_None;
-  assert(var->hasLocalStorage() && "capture added 'const' to non-local?");
+  ValueDecl *Value = dyn_cast<ValueDecl>(DRE->getDecl());
+
+  // The declaration must be a value which is not declared 'const'.
+  if (!Value || Value->getType().isConstQualified())
+    return NCCK_None;
+
+  BindingDecl *Binding = dyn_cast<BindingDecl>(Value);
+  if (Binding) {
+    assert(S.getLangOpts().CPlusPlus && "BindingDecl outside of C++?");
+    assert(!isa<BlockDecl>(Binding->getDeclContext()));
+    return NCCK_Lambda;
+  }
+
+  VarDecl *Var = dyn_cast<VarDecl>(Value);
+  if (!Var)
+    return NCCK_None;
+
+  assert(Var->hasLocalStorage() && "capture added 'const' to non-local?");
 
   // Decide whether the first capture was for a block or a lambda.
   DeclContext *DC = S.CurContext, *Prev = nullptr;
@@ -13261,16 +13317,16 @@ static NonConstCaptureKind isReferenceToNonConstCapture(Sema &S, Expr *E) {
     // For init-capture, it is possible that the variable belongs to the
     // template pattern of the current context.
     if (auto *FD = dyn_cast<FunctionDecl>(DC))
-      if (var->isInitCapture() &&
-          FD->getTemplateInstantiationPattern() == var->getDeclContext())
+      if (Var->isInitCapture() &&
+          FD->getTemplateInstantiationPattern() == Var->getDeclContext())
         break;
-    if (DC == var->getDeclContext())
+    if (DC == Var->getDeclContext())
       break;
     Prev = DC;
     DC = DC->getParent();
   }
   // Unless we have an init-capture, we've gone one step too far.
-  if (!var->isInitCapture())
+  if (!Var->isInitCapture())
     DC = Prev;
   return (isa<BlockDecl>(DC) ? NCCK_Block : NCCK_Lambda);
 }
@@ -19198,6 +19254,8 @@ bool Sema::NeedToCaptureVariable(ValueDecl *Var, SourceLocation Loc) {
 }
 
 QualType Sema::getCapturedDeclRefType(ValueDecl *Var, SourceLocation Loc) {
+  assert(Var && "Null value cannot be captured");
+
   QualType CaptureType;
   QualType DeclRefType;
 
@@ -19295,7 +19353,7 @@ static ExprResult rebuildPotentialResultsAsNonOdrUsed(Sema &S, Expr *E,
       if (VD->getType()->isReferenceType())
         return true;
       if (auto *RD = VD->getType()->getAsCXXRecordDecl())
-        if (RD->hasMutableFields())
+        if (RD->hasDefinition() && RD->hasMutableFields())
           return true;
       if (!VD->isUsableInConstantExpressions(S.Context))
         return true;