[Sema] Fix a use-after-free of a _Nonnull ParsedAttr

We were allocating the implicit attribute in the declarator's attribute pool,
but putting into the declaration specifier's ParsedAttributesView. If there are
multiple declarators, then we'll use the attribute from the declaration
specifier after clearing out the declarators attribute pool. Fix this by
allocating the attribute in the declaration specifier's pool.

rdar://48529718

Differential revision: https://reviews.llvm.org/D59327

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@356187 91177308-0d34-0410-b5e6-96231b3b80d8

Author: epilk

lib/Sema/SemaType.cpp

@@ -4189,7 +4189,7 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
   auto inferPointerNullability =
       [&](SimplePointerKind pointerKind, SourceLocation pointerLoc,
           SourceLocation pointerEndLoc,
-          ParsedAttributesView &attrs) -> ParsedAttr * {
+          ParsedAttributesView &attrs, AttributePool &Pool) -> ParsedAttr * {
     // We've seen a pointer.
     if (NumPointersRemaining > 0)
       --NumPointersRemaining;
@@ -4203,11 +4203,9 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
       ParsedAttr::Syntax syntax = inferNullabilityCS
                                       ? ParsedAttr::AS_ContextSensitiveKeyword
                                       : ParsedAttr::AS_Keyword;
-      ParsedAttr *nullabilityAttr =
-          state.getDeclarator().getAttributePool().create(
-              S.getNullabilityKeyword(*inferNullability),
-              SourceRange(pointerLoc), nullptr, SourceLocation(), nullptr, 0,
-              syntax);
+      ParsedAttr *nullabilityAttr = Pool.create(
+          S.getNullabilityKeyword(*inferNullability), SourceRange(pointerLoc),
+          nullptr, SourceLocation(), nullptr, 0, syntax);
 
       attrs.addAtEnd(nullabilityAttr);
 
@@ -4266,7 +4264,8 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
         if (auto *attr = inferPointerNullability(
                 pointerKind, D.getDeclSpec().getTypeSpecTypeLoc(),
                 D.getDeclSpec().getEndLoc(),
-                D.getMutableDeclSpec().getAttributes())) {
+                D.getMutableDeclSpec().getAttributes(),
+                D.getMutableDeclSpec().getAttributePool())) {
           T = state.getAttributedType(
               createNullabilityAttr(Context, *attr, *inferNullability), T, T);
         }
@@ -4306,7 +4305,8 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
 
       // Handle pointer nullability.
       inferPointerNullability(SimplePointerKind::BlockPointer, DeclType.Loc,
-                              DeclType.EndLoc, DeclType.getAttrs());
+                              DeclType.EndLoc, DeclType.getAttrs(),
+                              state.getDeclarator().getAttributePool());
 
       T = S.BuildBlockPointerType(T, D.getIdentifierLoc(), Name);
       if (DeclType.Cls.TypeQuals || LangOpts.OpenCL) {
@@ -4328,7 +4328,8 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
 
       // Handle pointer nullability
       inferPointerNullability(SimplePointerKind::Pointer, DeclType.Loc,
-                              DeclType.EndLoc, DeclType.getAttrs());
+                              DeclType.EndLoc, DeclType.getAttrs(),
+                              state.getDeclarator().getAttributePool());
 
       if (LangOpts.ObjC && T->getAs<ObjCObjectType>()) {
         T = Context.getObjCObjectPointerType(T);
@@ -4843,7 +4844,8 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
 
       // Handle pointer nullability.
       inferPointerNullability(SimplePointerKind::MemberPointer, DeclType.Loc,
-                              DeclType.EndLoc, DeclType.getAttrs());
+                              DeclType.EndLoc, DeclType.getAttrs(),
+                              state.getDeclarator().getAttributePool());
 
       if (SS.isInvalid()) {
         // Avoid emitting extra errors if we already errored on the scope.

test/SemaObjC/nonnull.m

@@ -125,3 +125,9 @@ void PR18795_helper() {
 }
 
 void (^PR23117)(int *) = ^(int *p1) __attribute__((nonnull(1))) {};
+
+typedef int *intptr;
+#pragma clang assume_nonnull begin
+intptr a, b;
+intptr c, (*d)();
+#pragma clang assume_nonnull end