Re: Is compiling Emacs with -finstrument-functions supported?

[Arthur Miller]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Arthur Miller <arthur.miller@live.com>
>> Date: Thu, 09 Dec 2021 18:11:13 +0100
>> 
>> temacs crashes when compiled with -finstrument-functions when it tries to
>> produce dump file:
>> 
>>   CC       json.o
>>   CC       terminfo.o
>>   CC       lastfile.o
>>   CCLD     temacs
>> /usr/bin/mkdir -p ../etc
>> make -C ../lisp update-subdirs
>> make[3]: Går till katalogen ”/home/arthur/repos/emacs-tests/emacs/lisp”
>> make[3]: Lämnar katalogen ”/home/arthur/repos/emacs-tests/emacs/lisp”
>> cp -f temacs bootstrap-emacs
>> rm -f bootstrap-emacs.pdmp
>> ./temacs --batch  -l loadup --temacs=pbootstrap \
>>         --bin-dest /usr/local/bin/ --eln-dest /usr/local/lib/emacs/29.0.50/
>> make[2]: *** [Makefile:908: bootstrap-emacs.pdmp] Segmenteringsfel 
>> (minnesdump)
>> make[2]: Lämnar katalogen ”/home/arthur/repos/emacs-tests/emacs/src”
>> make[1]: *** [Makefile:456: src] Fel 2
>> make[1]: Lämnar katalogen ”/home/arthur/repos/emacs-tests/emacs”
>> make: *** [Makefile:1166: bootstrap] Fel 2
>
> Can you run the failing command under GDB, and when it crashes, post
> the C-level backtrace?

Seems like I can not read function addresses:

$ gdb --args src/temacs --batch  -l loadup --temacs=pbootstrap --bin-dest  
--eln-dest
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Reading symbols from src/temacs...
(gdb) r
Starting program: /home/arthur/repos/emacs-tests/emacs/src/temacs --batch -l 
loadup --temacs=pbootstrap --bin-dest --eln-dest
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
0x000055555572c41c in __cyg_profile_func_enter (func=<error reading variable: 
Cannot access memory at address 0x7fffff66fff8>, caller=<error reading 
variable: Cannot access memory at address 0x7fffff66fff0>) at emacs.c:173       
                                                               
173     __cyg_profile_func_enter (void *func,  void *caller) {
(gdb)

I put my trace hooks in emacs.c. This is maybe nuts place to put them into? I
don't really know where I should put them, but it shouldn't matter? Or I am
wrong there?

static FILE *log_file = 0;
void __attribute__ ((constructor)) trace_begin (void);
void __attribute__ ((destructor)) trace_end (void);
void __cyg_profile_func_enter (void *func,  void *caller);
void __cyg_profile_func_exit (void *func, void *caller);

void
__attribute__ ((constructor))
trace_begin (void) {
 log_file = fopen("trace.log", "w");
}
 
void
__attribute__ ((destructor))
trace_end (void) {
 if(log_file) {
 fclose(log_file);
 }
}
 
void
__cyg_profile_func_enter (void *func,  void *caller) {
 if(log_file) {
 fprintf(log_file, "IN %p %p\n", func, caller);
 }
}

void
__cyg_profile_func_exit (void *func, void *caller) {
 if(log_file) {
 fprintf(log_file, "UT %p %p\n", func, caller);
 }
}