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digitalmars.D - dmd demangle

reply Arun Chandrasekaran <aruncxy gmail.com> writes:
Just a thought. Can dmd demangle the symbols before spitting the 
output of ld to stderr?
Aug 30 2017
next sibling parent reply Michael V. Franklin <slavo5150 yahoo.com> writes:
On Thursday, 31 August 2017 at 02:20:00 UTC, Arun Chandrasekaran 
wrote:

 Just a thought. Can dmd demangle the symbols before spitting 
 the output of ld to stderr?


dmd doesn't print the output of ld to stderr, ld does.

I believe binutils has some support for D symbol demangling 
thanks to the GDC folks.  I tried it once:  
http://forum.dlang.org/post/bdmsrcczmizevhxorquo forum.dlang.org

So I think you need to find a way to pass --demangle=dlang to ld. 
  Maybe `dmd program.d -L--demangle=dlang`?

Mike
Aug 30 2017
parent reply Arun Chandrasekaran <aruncxy gmail.com> writes:
On Thursday, 31 August 2017 at 02:31:24 UTC, Michael V. Franklin 
wrote:

 On Thursday, 31 August 2017 at 02:20:00 UTC, Arun 
 Chandrasekaran wrote:

 Just a thought. Can dmd demangle the symbols before spitting 
 the output of ld to stderr?


 dmd doesn't print the output of ld to stderr, ld does.

 I believe binutils has some support for D symbol demangling 
 thanks to the GDC folks.  I tried it once:  
 http://forum.dlang.org/post/bdmsrcczmizevhxorquo forum.dlang.org

 So I think you need to find a way to pass --demangle=dlang to 
 ld.
  Maybe `dmd program.d -L--demangle=dlang`?

 Mike


Thanks Mike.

I was looking at src/ddmd/link.d, has the below that reads the 
output of ld. So I was wondering if we can plugin the demangle 
logic in this function. Nevertheless, good to know the linker 
already supports it.

```
     private int findNoMainError(int fd)
     {
         version (OSX)
         {
             static __gshared const(char)* nmeErrorMessage = 
"\"__Dmain\", referenced from:";
         }
         else
         {
             static __gshared const(char)* nmeErrorMessage = 
"undefined reference to `_Dmain'";
         }
         FILE* stream = fdopen(fd, "r");
         if (stream is null)
             return -1;
         const(size_t) len = 64 * 1024 - 1;
         char[len + 1] buffer; // + '\0'
         size_t beg = 0, end = len;
         bool nmeFound = false;
         for (;;)
         {
             // read linker output
             const(size_t) n = fread(&buffer[beg], 1, len - beg, 
stream);
             if (beg + n < len && ferror(stream))
                 return -1;
             buffer[(end = beg + n)] = '\0';
             // search error message, stop at last complete line
             const(char)* lastSep = strrchr(buffer.ptr, '\n');
             if (lastSep)
                 buffer[(end = lastSep - &buffer[0])] = '\0';
             if (strstr(&buffer[0], nmeErrorMessage))
                 nmeFound = true;
             if (lastSep)
                 buffer[end++] = '\n';
             if (fwrite(&buffer[0], 1, end, stderr) < end)
                 return -1;
             if (beg + n < len && feof(stream))
                 break;
             // copy over truncated last line
             memcpy(&buffer[0], &buffer[end], (beg = len - end));
         }
         return nmeFound ? 1 : 0;
     }
```
Aug 30 2017
parent reply Michael V. Franklin <slavo5150 yahoo.com> writes:
On Thursday, 31 August 2017 at 02:51:25 UTC, Arun Chandrasekaran 
wrote:


 I was looking at src/ddmd/link.d, has the below that reads the 
 output of ld.


Ah, right you are.  My apologies.

It'd probably be simple enough to have that demangling on by 
default.  Maybe I'll give it a go later today.  What's your use 
case? Just getting unresolved symbols?

Mike
Aug 30 2017
parent Arun Chandrasekaran <aruncxy gmail.com> writes:
On Thursday, 31 August 2017 at 03:58:14 UTC, Michael V. Franklin 
wrote:


 Just getting unresolved symbols?


Yeah, I was just wondering what if the output can be readable, 
given that dmd is the one that invokes ld. Would be much more 
human readable without piping through ddemangle. Thanks.
Aug 30 2017
prev sibling next sibling parent ketmar <ketmar ketmar.no-ip.org> writes:
Arun Chandrasekaran wrote:


 Just a thought. Can dmd demangle the symbols before spitting the output 
 of ld to stderr?


no need to ;-) just add this to DFLAGS in dmd.conf, "Envirnment" section:

-L--demangle=dlang

so, it should look something like this:

..
[Environment]
DFLAGS=<your flags here> -L--demangle=dlang
..

due to hard work of Iain Buclaw, gdb and binutils (ld, objdump, etc.) are 
able to demangle DMD names.

note that new DMD version *may* include slightly changed mangling scheme, so 
the latest betas *may* produce "undecipherable" names.
Aug 30 2017
prev sibling parent ketmar <ketmar ketmar.no-ip.org> writes:
Arun Chandrasekaran wrote:


 Just a thought. Can dmd demangle the symbols before spitting the output 
 of ld to stderr?


p.s.: redirecting output to ddemangle may work too, as ddemange will try to 
detect mangled DMD names, and won't modify other text. this way you can, 
for example, demangle names in valgrind output.
Aug 30 2017