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digitalmars.D - Why are we not using libbacktrace for backtrace?

reply Yuxuan Shui <yshuiv7 gmail.com> writes:
Just ran into a problem where program will crash during stack 
trace. Turns out not only does druntime not support compressed 
debug info, it cannot handle it at all.

So I was thinking why don't we use a existing and proven library 
for this, instead of roll our own?
Jun 13 2018
next sibling parent reply Joakim <dlang joakim.fea.st> writes:
On Thursday, 14 June 2018 at 01:19:30 UTC, Yuxuan Shui wrote:

 Just ran into a problem where program will crash during stack 
 trace. Turns out not only does druntime not support compressed 
 debug info, it cannot handle it at all.

 So I was thinking why don't we use a existing and proven 
 library for this, instead of roll our own?


Druntime does use externally supplied backtrace, if available:

https://github.com/dlang/druntime/blob/master/src/core/runtime.d#L727
Jun 13 2018
parent Joakim <dlang joakim.fea.st> writes:
On Thursday, 14 June 2018 at 05:42:22 UTC, Joakim wrote:

 On Thursday, 14 June 2018 at 01:19:30 UTC, Yuxuan Shui wrote:

 Just ran into a problem where program will crash during stack 
 trace. Turns out not only does druntime not support compressed 
 debug info, it cannot handle it at all.

 So I was thinking why don't we use a existing and proven 
 library for this, instead of roll our own?


 Druntime does use externally supplied backtrace, if available:

 https://github.com/dlang/druntime/blob/master/src/core/runtime.d#L727


Hmm, but not on DWARF platforms like linux or macOS, I see what 
you mean. Should be pretty easy for you to modify that code to do 
what you want though.
Jun 13 2018
prev sibling parent reply Johannes Pfau <nospam example.com> writes:
Am Thu, 14 Jun 2018 01:19:30 +0000 schrieb Yuxuan Shui:


 Just ran into a problem where program will crash during stack trace.
 Turns out not only does druntime not support compressed debug info, it
 cannot handle it at all.
 
 So I was thinking why don't we use a existing and proven library for
 this, instead of roll our own?


GDC uses libbacktrace since 2013: https://github.com/D-Programming-GDC/
GDC/blob/master/libphobos/libdruntime/gcc/backtrace.d

I think the main problem for DMD/LDC is that libbacktrace is not an 
installed library, it's only available while building GCC.


-- 
Johannes
Jun 14 2018
parent reply Yuxuan Shui <yshuiv7 gmail.com> writes:
On Thursday, 14 June 2018 at 17:26:50 UTC, Johannes Pfau wrote:

 Am Thu, 14 Jun 2018 01:19:30 +0000 schrieb Yuxuan Shui:


 Just ran into a problem where program will crash during stack 
 trace. Turns out not only does druntime not support compressed 
 debug info, it cannot handle it at all.
 
 So I was thinking why don't we use a existing and proven 
 library for this, instead of roll our own?


 GDC uses libbacktrace since 2013: 
 https://github.com/D-Programming-GDC/ 
 GDC/blob/master/libphobos/libdruntime/gcc/backtrace.d

 I think the main problem for DMD/LDC is that libbacktrace is 
 not an installed library, it's only available while building 
 GCC.


libbacktrace is a standalone library: 
https://github.com/ianlancetaylor/libbacktrace

GCC is using it.
Jun 14 2018
parent Johannes Pfau <nospam example.com> writes:
Am Thu, 14 Jun 2018 20:57:05 +0000 schrieb Yuxuan Shui:


 On Thursday, 14 June 2018 at 17:26:50 UTC, Johannes Pfau wrote:

 Am Thu, 14 Jun 2018 01:19:30 +0000 schrieb Yuxuan Shui:


 Just ran into a problem where program will crash during stack trace.
 Turns out not only does druntime not support compressed debug info, it
 cannot handle it at all.
 
 So I was thinking why don't we use a existing and proven library for
 this, instead of roll our own?


 GDC uses libbacktrace since 2013: https://github.com/D-Programming-GDC/
 GDC/blob/master/libphobos/libdruntime/gcc/backtrace.d

 I think the main problem for DMD/LDC is that libbacktrace is not an
 installed library, it's only available while building GCC.


 
 libbacktrace is a standalone library:
 https://github.com/ianlancetaylor/libbacktrace
 
 GCC is using it.


It was initially developed for GCC and only available in the GCC tree. 
Ian Lance Taylor is a GCC developer.

However, my point is that libbacktrace does not install as a .so shared 
library. Try to find packages for debian, rhel, ... It's just not 
distributed.
As there is a standalone github repo now, the DMD builds could probably 
compile the source code into libdruntime like GCC does, but it's not as 
simple as linking a library.

-- 
Johannes
Jun 14 2018