Comment # 17 on bug 1000513 from Jiri Slaby

(In reply to Jiri Slaby from comment #1)
> Created attachment 693723 [details]
> potential fix

Reopening as this patch is still needed. No matter whether glibc-debuginfo is
installed or not, it behaves the same. Important is how the code below is
compiled (-g -Og needed).

Source:
#include <stdio.h>

int main(void)
{
        fwrite("a", 1, 1, stdout);
        fwrite("b", 1, 1, stdout);
        fwrite("\n", 1, 1, stdout);

        return 0;
}

Build:
gcc tracer.c -Og -g

Without the patch:
$ ltrace ./a.out 
fwrite()                                         = <void>
fwrite()                                         = <void>
fwrite(ab
)                                         = <void>
+++ exited (status 0) +++

With the patch:
ltrace ./a.out 
fwrite("a", 1, 1, 0x7f049ee5b760)                = 1
fwrite("b", 1, 1, 0x7f049ee5b760)                = 1
fwrite("\n", 1, 1, 0x7f049ee5b760ab
)               = 1
+++ exited (status 0) +++

I tried to build with all these flags, but the issue is not reproducible, so Og
must enable some more:
  -fcombine-stack-adjustments 
  -fcompare-elim              
  -fcprop-registers           
  -fdefer-pop                 
  -fforward-propagate         
  -fguess-branch-probability  
  -fipa-profile               
  -fipa-pure-const            
  -fipa-reference             
  -fomit-frame-pointer        
  -freorder-blocks            
  -fshrink-wrap               
  -fsplit-wide-types          
  -ftree-builtin-call-dce     
  -ftree-ccp                  
  -ftree-coalesce-vars        
  -ftree-copy-prop            
  -ftree-dce                  
  -ftree-dominator-opts       
  -ftree-dse                  
  -ftree-fre                  
  -ftree-ch                   
  -ftree-sink                 
  -ftree-slsr                 
  -ftree-ter