source: tests/const-init.cfa@ 4be0117

//
// Cforall Version 1.0.0 Copyright (C) 2020 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// const-init.cfa -- tests of initializing constants
//
// Author           : Michael Brooks
// Created On       : Tue Oct 06 22:00:00 2020
// Last Modified By : Michael Brooks
// Last Modified On : Tue Oct 06 22:00:00 2020
// Update Count     : 1
//

/*

These tests show non-crashing of generated code for constants with interesting initializers.
The potential for these to crash is compiler dependent.

There are two cases:
1. static constants in one compilation unit (tested here, in a few sub-cases)
2. extern constants across compilation units (tested by libcfa being loadable, specifically
   the constant definitions in libcfa/src/limits.cfa, which almost every test exercises,
   including "hello;" but notably, the "limits" test does not exercise it because that test
   is compile-only)

Crashes that we have obsrved (#182 and build failures September 2020) are because the libcfa
initialization is writing to a global variable (which the declaring program wants typed as 
constant), while the compiler has placed this global in a read-only section.

Compiler dependence includes:

                          Case 1           Case 2
GCC-6  on Ubuntu 16.04    Never crashed    Never crashed
GCC-8  on both            Has crashed      Never crashed
GCC-10 on Ubuntu 20.04    Has crashed      Has crashed

For this test to fail, with most other tests passing, would be a situation only ever
observed with GCC-8.

*/

// initailized by generated function, called before main
static const char foo = -1;

struct thing{};
void ^?{}( thing & ) { printf("dtor\n"); }

int main() {
    // foo is already initialized

    // no dtor => stays a (static) local, initialized here
    static const char bar = -1;

    // has dtor => becomes a global, ctor called here, dtor called at exit
    static const thing it;

    printf("almost done\n");
}