[LLVMdev] How much memory clang llvm needs for debug compiling?

[Gabor Ballabas]

Hi Nancy,

Have you tried setting follow-fork-mode to the child process?

https://sourceware.org/gdb/onlinedocs/gdb/Forks.html

Best regards,
Gabor Ballabas

On 06/04/2014 04:42 PM, Nancy wrote:
> On Wed, Jun 4, 2014 at 5:16 AM, Eric Christopher <echristo at gmail.com> wrote:
>> On Tue, Jun 3, 2014 at 7:59 AM, Nancy <nancydreaming at gmail.com> wrote:
>>>> First, you could switch to ld.gold instead of ld.bfd. It uses much
>>>   $ln -s `which gold` /usr/local/bin/ld
>>>
>>>> the idea. I think for autoconf you need ".../configure
>>>> --enable-split-dwarf" to use this.
>>>>
>>>   $.../configure --enable-targets=x86 --enable-split-dwarf
>>>   $ make -j2
>>>   $ sudo make install
>>>
>>> It works for me. Thanks a lot!
>>>
>>> I want to use emacs+gdb to trace the code work flow.
>>> M-x gdb
>>> Run like gdb --annotate=3 clang
>>> (gdb) set args test.c
>>> (gdb) b main
>>> (gdb) b /home/nancy/work/llvm/tools/clang/lib/Lex/Lexer.cpp:57
>>> (gdb) r
>>>   It block at llvm/tools/clang/tools/driver/driver.cpp  main() fucntion.
>>> (gdb) c
>>>   program exit normally
>>>   why? why it not call Lexer.cpp:InitLexer()? And I really can't find
>>> any entry point to clang/lib/*.cpp files within help of SourceInsight
>>> code view start from llvm/tools/clang/tools/driver/driver.cpp  main()
>>> function.
>>>
>>> What's wrong with me?
>>>
>> You need to use the -cc1 option that clang is being reinvoked with,
>> use the -v option on your original command line to take a look at it.
>>
>> Also, if you're just doing development you don't need to install the
>> binary. The clang in build/Debug+Asserts/bin/clang will work just
>> fine.
>>
>> -eric
> Hi, eric
>
>     Thank you for your -v advice
>
> $clang -v test.c
> ....
>
> Selected GCC installation: /usr/lib/gcc/i686-linux-gnu/4.8
> Candidate multilib: .;@m32
> Selected multilib: .;@m32
>   "/usr/local/bin/clang" -cc1 -triple i386-pc-linux-gnu -emit-obj
> -mrelax-all -disable-free -main-file-name test.c -mrelocation-model
> static -mdisable-fp-elim -fmath-errno -masm-verbose
> -mconstructor-aliases -fuse-init-array -target-cpu pentium4
> -target-linker-version 2.24 -v -resource-dir
> /usr/local/bin/../lib/clang/3.5.0 -internal-isystem /usr/local/include
> -internal-isystem /usr/local/bin/../lib/clang/3.5.0/include
> -internal-externc-isystem /usr/include/i386-linux-gnu
> -internal-externc-isystem /include -internal-externc-isystem
> /usr/include -fdebug-compilation-dir /home/nancy/work/test
> -ferror-limit 19 -fmessage-length 80 -mstackrealign -fobjc-runtime=gcc
> -fdiagnostics-show-option -o /tmp/test-85913a.o -x c test.c
>
> clang -cc1 version 3.5.0 based upon LLVM 3.5.0svn default target
> i386-pc-linux-gnu
> ignoring nonexistent directory "/include"
> #include "..." search starts here:
> #include <...> search starts here:
>   /usr/local/include
>   /usr/local/bin/../lib/clang/3.5.0/include
>   /usr/include/i386-linux-gnu
>   /usr/include
> End of search list.
> ......
>
> I use
> "-cc1 -triple i386-pc-linux-gnu -emit-obj -mrelax-all -disable-free
> -main-file-name test.c -mrelocation-model static -mdisable-fp-elim
> -fmath-errno -masm-verbose -mconstructor-aliases -fuse-init-array
> -target-cpu pentium4 -target-linker-version 2.24 -v -resource-dir
> /usr/local/bin/../lib/clang/3.5.0 -internal-isystem /usr/local/include
> -internal-isystem /usr/local/bin/../lib/clang/3.5.0/include
> -internal-externc-isystem /usr/include/i386-linux-gnu
> -internal-externc-isystem /include -internal-externc-isystem
> /usr/include -fdebug-compilation-dir /home/nancy/work/test
> -ferror-limit 19 -fmessage-length 80 -mstackrealign -fobjc-runtime=gcc
> -fdiagnostics-show-option -o /tmp/test-85913a.o -x c
> /home/nancy/work/test/test.c"
>
> as (gdb)set args parameters and setup those breakpoins and run, it
> still normally exist without stopping at breakpoint I set in
> Lexer.cpp.
>
> Could you please tell me the specific steps?
>