www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.learn - State of Windows x64 COFF support?

reply Etienne <etcimon gmail.com> writes:
I'm having corrupt symbol table errors on a Win64 build of a big 
application, I can't find a way around it. I'm wondering if the COFF 
support is still experimental in DMD?

Thanks!
Feb 19 2015
parent reply Etienne <etcimon gmail.com> writes:
On 2015-02-19 11:39 AM, Etienne wrote:

 I'm having corrupt symbol table errors on a Win64 build of a big
 application, I can't find a way around it. I'm wondering if the COFF
 support is still experimental in DMD?

 Thanks!


I just counted 67k sections using a printf in DMD... The limit is 65k so 
that explains that.
Feb 19 2015
parent reply ketmar <ketmar ketmar.no-ip.org> writes:
On Thu, 19 Feb 2015 13:29:58 -0500, Etienne wrote:


 On 2015-02-19 11:39 AM, Etienne wrote:

 I'm having corrupt symbol table errors on a Win64 build of a big
 application, I can't find a way around it. I'm wondering if the COFF
 support is still experimental in DMD?

 Thanks!


=20
 I just counted 67k sections using a printf in DMD... The limit is 65k so
 that explains that.


i remember that DMD creates one section for each function (to allow=20
smartlink feature). with templates this can be alot. maybe it needs new=20
cli flag "--collapse-sections" or something like it.=
Feb 19 2015
parent reply Etienne <etcimon gmail.com> writes:
On 2015-02-19 1:41 PM, ketmar wrote:

 i remember that DMD creates one section for each function (to allow
 smartlink feature). with templates this can be alot. maybe it needs new
 cli flag "--collapse-sections" or something like it.


I watched the section names and discovered over 20,000 sections named : 
.debug$S

According to the code, a new .debug$S section is created every time it 
is searched with the flag IMAGE_SCN_LNK_COMDAT in:

https://github.com/D-Programming-Language/dmd/blob/de6fccf8391b1dfdb959fa0f089920c2c8e6aff8/src/backend/mscoffobj.c#L1724

I deleted this flag and now the program links correctly with COFF with 
<50k sections.

It would have been easier to debug with an error in mscoffobj.c:1591:

assert(scnhdr_cnt < 65536, "Too many symbols for COFF format");

https://github.com/D-Programming-Language/dmd/blob/de6fccf8391b1dfdb959fa0f089920c2c8e6aff8/src/backend/mscoffobj.c#L1591

With this simple patch on the compiler, there are stil some errors 
compiling Botan on win64, but they are not related to the COFF format 
anymore.
Feb 19 2015
parent "Kagamin" <spam here.lot> writes:
Implementations can have bugs, probably COFF support wasn't 
stress tested.
Feb 20 2015