Merge commit '8835b75a8ce3' from swift/release/6.2 into stable/20240723

Author: git apple-llvm automerger

clang/lib/AST/ASTContext.cpp

@@ -3707,21 +3707,6 @@ QualType ASTContext::mergeBoundsSafetyPointerTypes(
   if (OrigDstTy.isNull())
     OrigDstTy = DstTy;
 
-  // An ugly way to keep va_list typedef in DstTy if the merge type doesn't
-  // change.
-  // TODO: We need a general way of not stripping sugars.
-  QualType DesugaredDstTy;
-  if (const auto *TDT = dyn_cast<TypedefType>(DstTy))
-    DesugaredDstTy = TDT->desugar();
-  else if (const auto *ET = dyn_cast<ElaboratedType>(DstTy))
-    DesugaredDstTy = ET->desugar();
-  if (!DesugaredDstTy.isNull()) {
-    QualType MergeTy = mergeBoundsSafetyPointerTypes(DesugaredDstTy, SrcTy,
-                                                     MergeFunctor, OrigDstTy);
-    if (MergeTy == DesugaredDstTy)
-      return DstTy;
-  }
-
   // FIXME: a brittle hack to avoid skipping ValueTerminatedType outside
   // this PtrAutoAttr AttributedType.
   bool RecoverPtrAuto = false;

clang/lib/Sema/SemaDecl.cpp

@@ -4040,12 +4040,33 @@ static bool mergeFunctionDeclBoundsAttributes(FunctionDecl *New,
     }
     return MergeTy;
   };
+
+  auto hasBoundsAttributesAtAnyLevel = [](QualType Ty) -> bool {
+    while (Ty->isPointerType()) {
+      if (!Ty->isUnspecifiedPointerType())
+        return true;
+      Ty = Ty->getPointeeType();
+    }
+    return false;
+  };
+
+  auto mergePointersWithAttributes = [&](QualType NewTy,
+                                         QualType OldTy) -> QualType {
+    // Do not attempt to merge if there is no need to do so. This will let us
+    // keep the sugars used in the new declaration.
+    if (!hasBoundsAttributesAtAnyLevel(NewTy) &&
+        !hasBoundsAttributesAtAnyLevel(OldTy))
+      return NewTy;
+    return Self.Context.mergeBoundsSafetyPointerTypes(NewTy, OldTy,
+                                                      mergeBoundsAttributes);
+  };
+
   QualType NewRetTy = New->getReturnType();
   if (NewRetTy->isBoundsAttributedType() ||
       NewRetTy->isValueTerminatedType())
     return false;
-  QualType MergeRetTy = Self.Context.mergeBoundsSafetyPointerTypes(
-      New->getReturnType(), Old->getReturnType(), mergeBoundsAttributes);
+  QualType MergeRetTy =
+      mergePointersWithAttributes(New->getReturnType(), Old->getReturnType());
   if (MergeRetTy.isNull())
     return false;
 
@@ -4055,9 +4076,8 @@ static bool mergeFunctionDeclBoundsAttributes(FunctionDecl *New,
     if (NewParmTy->isBoundsAttributedType() ||
         NewParmTy->isValueTerminatedType())
       return false;
-    QualType MergeParamTy = Self.Context.mergeBoundsSafetyPointerTypes(
-        NewParmTy, Old->getParamDecl(i)->getType(),
-        mergeBoundsAttributes);
+    QualType MergeParamTy =
+        mergePointersWithAttributes(NewParmTy, Old->getParamDecl(i)->getType());
     if (MergeParamTy.isNull())
       return false;
     if (const auto *CATy = MergeParamTy->getAs<CountAttributedType>()) {

clang/test/BoundsSafety/AST/system-header-merge-bounds-attributed.c

@@ -29,6 +29,9 @@
 // CHECK: FunctionDecl {{.+}} eb
 // CHECK: |-ParmVarDecl {{.+}} eb_p 'void *'
 // CHECK: `-ParmVarDecl {{.+}} end 'void *'
+// CHECK: FunctionDecl {{.+}} cb_array
+// CHECK: |-ParmVarDecl {{.+}} array 'int *'
+// CHECK: `-ParmVarDecl {{.+}} len 'int'
 
 
 // Check if we can override them.
@@ -39,6 +42,7 @@ void cb_out_count(int *__counted_by(*len) cb_out_len_p, int *len);
 void cbn(int *__counted_by_or_null(len) cbn_p, int len);
 void sb(void *__sized_by(size) sb_p, int size);
 void eb(void *__ended_by(end) eb_p, void *end);
+void cb_array(int array[__counted_by(len)], int len);
 
 // CHECK: FunctionDecl {{.+}} prev {{.+}} cb_in
 // CHECK: |-ParmVarDecl {{.+}} cb_in_p 'int *{{.*}} __counted_by(len)'
@@ -58,6 +62,9 @@ void eb(void *__ended_by(end) eb_p, void *end);
 // CHECK: FunctionDecl {{.+}} prev {{.+}} eb
 // CHECK: |-ParmVarDecl {{.+}} used eb_p 'void *{{.*}} __ended_by(end)'
 // CHECK: `-ParmVarDecl {{.+}} used end 'void *{{.*}} /* __started_by(eb_p) */ '
+// CHECK: FunctionDecl {{.+}} prev {{.+}} cb_array
+// CHECK: |-ParmVarDecl {{.+}} array 'int *{{.*}} __counted_by(len)'
+// CHECK: `-ParmVarDecl {{.+}} used len 'int'
 
 
 // Check if the attributes are merged.
@@ -82,3 +89,6 @@ void eb(void *__ended_by(end) eb_p, void *end);
 // CHECK: FunctionDecl {{.+}} prev {{.+}} eb
 // CHECK: |-ParmVarDecl {{.+}} used eb_p 'void *{{.*}} __ended_by(end)'
 // CHECK: `-ParmVarDecl {{.+}} used end 'void *{{.*}} /* __started_by(eb_p) */ '
+// CHECK: FunctionDecl {{.+}} prev {{.+}} cb_array
+// CHECK: |-ParmVarDecl {{.+}} array 'int *{{.*}} __counted_by(len)'
+// CHECK: `-ParmVarDecl {{.+}} used len 'int'

clang/test/BoundsSafety/AST/system-header-merge-bounds-attributed.h

@@ -6,3 +6,4 @@ void cb_out_count(int *cb_out_len_p, int *len);
 void cbn(int *cbn_p, int len);
 void sb(void *sb_p, int size);
 void eb(void *eb_p, void *end);
+void cb_array(int array[], int len);