[dmd-internals] Struct initialization in nested functions

[Sean Kelly]

This is on OSX. I'll have to come up with a functional minimal example. 

On Jan 17, 2013, at 2:13 PM, Maxim Fomin <maxim at maxim-fomin.ru> wrote:

> Are you debugging this on OSX?
> 
> In linux these three runs fine and throws exceptions because of absent URL. 
> However after adding "dlang.org" argument in each of three cases to watch performance,
> valgrind shows memory errors which are finally detected in druntime (gc.gcx.mark, gc.gcx.findpool, etc.),
> so there is something wrong with curl module or druntime.
> 
> Does valgrind detect errors in your installation for #1 and #3?
> 
> 2013/1/17 Sean Kelly <sean at invisibleduck.org>
>> Here are three variations of code using the curl client.  The first works, the second fails with a segfault, and the third works:
>> 
>> 
>> #1
>> 
>> void main() {
>>    auto http = HTTP();
>>    go(http);
>> }
>> 
>> void go(ref HTTP http) {
>>    // compose request
>>    http.perform();
>> }
>> 
>> works!
>> 
>> 
>> #2
>> 
>> void main() {
>>    HTTP http;
>>    init(http);
>>    go(http);
>> }
>> 
>> void init(ref HTTP http) {
>>    http = HTTP();
>> }
>> 
>> void go(ref HTTP http) {
>>    // compose request
>>    http.perform();
>> }
>> 
>> segfault! (see below)
>> 
>> 
>> #3
>> 
>> void main() {
>>    HTTP http;
>>    init(http);
>>    go(http);
>> }
>> 
>> void init(ref HTTP http) {
>>    http.__ctor(null);
>> }
>> 
>> void go(ref HTTP http) {
>>    // compose request
>>    http.perform();
>> }
>> 
>> works!
>> 
>> 
>> I'm guessing the segfault in the second case is a compiler bug, but I haven't tried to narrow it down yet.  The problem initially came up because I wanted to use the HTTP struct as a class member, and the documented means for initializing it was causing a segfault.  Here's the stack trace:
>> 
>> 
>> Program received signal EXC_BAD_ACCESS, Could not access memory.
>> Reason: KERN_PROTECTION_FAILURE at address: 0x00000001000028ec
>> 0x0000000100077803 in D3std3net4curl4HTTP15onReceiveHeaderMFNdDFxAaxAaZvZv12__lambda2026MFxAaZv ()
>> (gdb) bt
>> #0  0x0000000100077803 in D3std3net4curl4HTTP15onReceiveHeaderMFNdDFxAaxAaZvZv12__lambda2026MFxAaZv ()
>> #1  0x0000000100078bfd in D3std3net4curl4Curl15onReceiveHeaderMFNdDFxAaZvZv12__lambda2029MFxAaZv ()
>> #2  0x0000000100078e75 in _D3std3net4curl4Curl22_receiveHeaderCallbackUxPammPvZm ()
>> #3  0x00007fff98ed6eb9 in Curl_client_write ()
>> #4  0x00007fff98ed616f in Curl_http_readwrite_headers ()
>> #5  0x00007fff98eebe11 in Curl_readwrite ()
>> #6  0x00007fff98eed709 in Curl_do_perform ()
>> #7  0x0000000100078a3b in D3std3net4curl4Curl7performMFbZi ()
>> #8  0x00000001000770f8 in D3std3net4curl4HTTP8_performMFbZi ()
>> #9  0x0000000100076e9a in D3std3net4curl4HTTP7performMFZv ()
>> #10 function go(ref HTTP)
>> #11 function main()
>> 
>> 
>> Can someone confirm that either the static opCall method that HTTP uses for initialization is bad and should be changed, or that this is a compiler issue?
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