How to retrieve the GCC version used to compile a given ELF executable?

Question

I'd like to retrieve the GCC version used to compile a given executable. I tried readelf but didn't get the information. Any thoughts?

-Ilyes

Answer 1

This information is not stored in the compiled object.

Answer 2

This information is not stored in the compiled object (c).

Actually, for C code you're totally out of luck. However, for C++ code you may find some information from symbol versions. Some functions from C++ runtime libraries are version-specific, and are marked as such in object files. Try this:

readelf -Wa file.exe | grep 'GCC[[:alnum:]_.]*' --only-match | sort | uniq | tail -n 1

It won't show you the version of GCC used, however. What it shows is the version of symbols in runtime supplied to the compiler. Usually the runtime is that of a compiler shipment, and its version is not less than the one shown with the above command.

Answer 3

To complete what others have said: it's not stored in the object (or exe) file, unless you compile with debugging information! (option -g). If you compile with debug info, you can get it back with readelf:

$ cat a.c
int main(void){ return 0; }
$ gcc a.c
$ readelf -wi a.out
$ gcc a.c -g       
$ readelf -wi a.out
Contents of the .debug_info section:

  Compilation Unit @ offset 0x0:
   Length:        0x42 (32-bit)
   Version:       2
   Abbrev Offset: 0
   Pointer Size:  4
 <0><b>: Abbrev Number: 1 (DW_TAG_compile_unit)
    < c>   DW_AT_producer    : (indirect string, offset: 0x0): GNU C 4.4.3 20100108 (prerelease)    
    <10>   DW_AT_language    : 1    (ANSI C)
    <11>   DW_AT_name        : a.c  
    <15>   DW_AT_comp_dir    : (indirect string, offset: 0x22): /tmp    
    <19>   DW_AT_low_pc      : 0x8048394    
    <1d>   DW_AT_high_pc     : 0x804839e    
    <21>   DW_AT_stmt_list   : 0x0  
 <1><25>: Abbrev Number: 2 (DW_TAG_subprogram)
    <26>   DW_AT_external    : 1    
    <27>   DW_AT_name        : (indirect string, offset: 0x27): main    
    <2b>   DW_AT_decl_file   : 1    
    <2c>   DW_AT_decl_line   : 1    
    <2d>   DW_AT_prototyped  : 1    
    <2e>   DW_AT_type        : <0x3e>   
    <32>   DW_AT_low_pc      : 0x8048394    
    <36>   DW_AT_high_pc     : 0x804839e    
    <3a>   DW_AT_frame_base  : 0x0  (location list)
 <1><3e>: Abbrev Number: 3 (DW_TAG_base_type)
    <3f>   DW_AT_byte_size   : 4    
    <40>   DW_AT_encoding    : 5    (signed)
    <41>   DW_AT_name        : int  

See how it says GNU C 4.4.3 20100108 (prerelease).