On Wednesday, 22 November 2017 at 15:33:46 UTC, Anonymouse wrote:
On Tuesday, 21 November 2017 at 19:22:47 UTC, Anonymouse wrote:
Compiling a debug dmd and running the build command in gdb, it
seems to be a stack overflow at ddmd/dtemplate.d:6241,
TemplateInstance::needsCodegen().
After a lot of trial and error I managed to find /a/ line which
lets it compile under -b plain and release.
void colour(Sink, Codes...)(auto ref Sink sink, const Codes
codes)
{
// Sink is a LockingTextWriter or an Appender!string
// Codes is a tuple of named enum members
foreach (const code; codes)
{
import std.conv : to;
if (++numCodes > 1) sink.put(';');
sink.put((cast(size_t)code).to!string); // <--
}
Change size_t to uint and it compiles, keep it size_t and the
compiler segfaults. Tested on two machines, both running
up-to-date Arch linux, both with dmd and ldc.
The bug is too ephemeral to reduce well, if a thing like order
of arguments matters.
If this is an emergent property of the rest of the program, and
the size_t merely fells the house of cards, is it even worth
reporting when I can't reduce it?
You did a good investigation and I still think it's important to
report it.
I managed to find a few other cases where people were having
issues with needsCodegen:
https://github.com/ldc-developers/ldc/issues/2168#issuecomment-312709632
https://github.com/ldc-developers/ldc/issues/2336
https://github.com/ldc-developers/ldc/issues/2022#issuecomment-288481397
https://github.com/ldc-developers/ldc/issues/1297#issuecomment-184770787
So there's enough evidence that there's a bug somewhere around
that part of the compiler and we should gather good test cases to
narrow down the problem.
