tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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source.cpp (1633B)


      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 // Simply including <exception> was enough to crash sixgill at one point.
      8 #include <exception>
      9 
     10 #define ANNOTATE(property) __attribute__((annotate(property)))
     11 
     12 struct Cell {
     13  int f;
     14 } ANNOTATE("GC Thing");
     15 
     16 extern void GC() ANNOTATE("GC Call");
     17 
     18 void GC() {
     19  // If the implementation is too trivial, the function body won't be emitted at
     20  // all.
     21  asm("");
     22 }
     23 
     24 class RAII_GC {
     25 public:
     26  RAII_GC() {}
     27  ~RAII_GC() { GC(); }
     28 };
     29 
     30 // ~AutoSomething calls GC because of the RAII_GC field. The constructor,
     31 // though, should *not* GC -- unless it throws an exception. Which is not
     32 // possible when compiled with -fno-exceptions. This test will try it both
     33 // ways.
     34 class AutoSomething {
     35  RAII_GC gc;
     36 
     37 public:
     38  AutoSomething() : gc() {
     39    asm("");  // Ooh, scary, this might throw an exception
     40  }
     41  ~AutoSomething() { asm(""); }
     42 };
     43 
     44 extern Cell* getcell();
     45 
     46 extern void usevar(Cell* cell);
     47 
     48 void f() {
     49  Cell* thing = getcell();  // Live range starts here
     50 
     51  // When compiling with -fexceptions, there should be a hazard below. With
     52  // -fno-exceptions, there should not be one. We will check both.
     53  {
     54    AutoSomething smth;  // Constructor can GC only if exceptions are enabled
     55    usevar(thing);       // Live range ends here
     56  }  // In particular, 'thing' is dead at the destructor, so no hazard
     57 }