https://issues.dlang.org/show_bug.cgi?id=15399
Issue ID: 15399
Summary: unaligned pointers are not @safe
Product: D
Version: D2
Hardware: All
OS: All
Status: NEW
Keywords: accepts-invalid, safe
Severity: major
Priority: P1
Component: dmd
Assignee: [email protected]
Reporter: [email protected]
This @safe program produces dangling GC pointers by storing the only references
to them in an unaligned struct field:
//////////////////////////////// test.d ////////////////////////////////
@safe:
struct Victim
{
bool alive = true;
~this() { alive = false; }
}
align(1)
struct Unaligned
{
align(1):
ubyte filler;
Victim* p;
}
pragma(msg, Unaligned.sizeof);
void main()
{
enum N = 100;
Unaligned[N] hosts;
foreach (n; 0..N)
{
hosts[n].p = new Victim;
assert(hosts[n].p.alive);
}
// Unaligned.p is invisible to the GC due to alignment
void trustedCollect() @trusted { import core.memory; GC.collect(); }
trustedCollect();
foreach (n; 0..N)
assert(hosts[n].p.alive); // Dangling pointer!
}
////////////////////////////////////////////////////////////////////////
--
