Commit d1b122cb authored by Hans Wennborg's avatar Hans Wennborg
Browse files

Merging r367134: 

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r367134 | nathan-huckleberry | 2019-07-26 19:29:35 +0200 (Fri, 26 Jul 2019) | 16 lines

[Sema] Fix -Wuninitialized for struct assignment from GNU C statement expression

Summary:
Do not automatically report self references of structs in statement expression
as warnings. Instead wait for uninitialized cfg analysis.
https://bugs.llvm.org/show_bug.cgi?id=42604

Reviewers: aaron.ballman, rsmith, nickdesaulniers

Reviewed By: aaron.ballman, nickdesaulniers

Subscribers: nathanchance, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D64678
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llvm-svn: 367150
parent e2025880

clang/lib/Sema/SemaDecl.cpp

+6 −3
Original line number Diff line number Diff line
@@ -11527,10 +11527,13 @@ void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init, bool DirectInit) { 
  // Check for self-references within variable initializers.

  // Variables declared within a function/method body (except for references)

  // are handled by a dataflow analysis.

  // This is undefined behavior in C++, but valid in C.

  if (getLangOpts().CPlusPlus) {

    if (!VDecl->hasLocalStorage() || VDecl->getType()->isRecordType() ||

        VDecl->getType()->isReferenceType()) {

      CheckSelfReference(*this, RealDecl, Init, DirectInit);

    }

  }















  // If the type changed, it means we had an incomplete type that was















  // completed by the initializer. For example:

































clang/test/Sema/warn-uninitialized-statement-expression.c
0 → 100644



+56
−0






























Original line number
Diff line number
Diff line













// RUN: %clang_cc1 -fsyntax-only -Wuninitialized -verify %s



























void init(int *);



























void foo(void) {













  int i = ({













    init(&i);













    i;













  });













}



























void foo_bad(void) {













  int i = ({













    int z = i; // expected-warning{{variable 'i' is uninitialized when used within its own initialization}}













    init(&i);













    i;













  });













}



























struct widget {













  int x, y;













};













void init2(struct widget *);



























void bar(void) {













  struct widget my_widget = ({













    init2(&my_widget);













    my_widget;













  });













  struct widget a = (init2(&a), a);













}



























void bar_bad(void) {













  struct widget my_widget = ({













    struct widget z = my_widget; // expected-warning{{variable 'my_widget' is uninitialized when used within its own initialization}}













    int x = my_widget.x;         //FIXME: There should be an uninitialized warning here













    init2(&my_widget);













    my_widget;













  });













}



























void baz(void) {













  struct widget a = ({













    struct widget b = ({













      b = a; // expected-warning{{variable 'a' is uninitialized when used within its own initialization}}













    });













    a;













  });













}



























void f(void) {













  struct widget *a = ({













    init2(a); // expected-warning{{variable 'a' is uninitialized when used within its own initialization}}













    a;













  });













}