Re: worrying differences in object code due to different build host!

[Andrew Cagney <andrew.cagney%gmail.com@localhost>]

Did the size or alignment of "struct ibcs2_dirent idb" change?

2696c2696
<  2508 152f 899DD0FD   movl %ebx,-560(%ebp)
---
>  2508 152f 899DD4FD   movl %ebx,-556(%ebp)
2700c2700
<  2510 153b 8D85D8FD   leal -552(%ebp),%eax
---
>  2510 153b 8D85DCFD   leal -548(%ebp),%eax
2715c2715
<  2520 1565 8B85D8FD   movl -552(%ebp),%eax
---
>  2520 1565 8B85DCFD   movl -548(%ebp),%eax
2787c2787
<  2567 1624 8B85D8FD   movl -552(%ebp),%eax
---
>  2567 1624 8B85DCFD   movl -548(%ebp),%eax
2832c2832
<  2592 16a3 8D85D0FD   leal -560(%ebp),%eax
---
>  2592 16a3 8D85D4FD   leal -556(%ebp),%eax
2835c2835
<  2594 16ad 8B85D8FD   movl -552(%ebp),%eax
---
>  2594 16ad 8B85DCFD   movl -548(%ebp),%eax
2837c2837
<  2595 16b3 8D8DDCFD   leal -548(%ebp),%ecx
---
>  2595 16b3 8D8DD0FD   leal -560(%ebp),%ecx

This seems to be the highest problematic address - presumably somehing around here changed.  Rooting around the .debug_info, by luck, I find (if it was a complicated location _expression_ it would quickly get tedious).

 <2><31040e>: Abbrev Number: 73 (DW_TAG_variable)
    <31040f>   DW_AT_name        : idb 
    <310413>   DW_AT_decl_file   : 1   
    <310414>   DW_AT_decl_line   : 382 
    <310416>   DW_AT_type        : <0x30ceb4>  
    <31041a>   DW_AT_location    : 3 byte block: 91 dc 7b       (DW_OP_fbreg: -548)

(DW_OP_fbreg == DW_AT_frame_base == is probably ebp)

I can then search for <30ceb4> and find the actual type:

 <1><30ceb4>: Abbrev Number: 14 (DW_TAG_structure_type)
    <30ceb5>   DW_AT_name        : (indirect string, offset: 0x214db): ibcs2_dirent    

followed by its layout described in dwarf.

Andrew

2839c2839
<  2596 16b9 8D95D4FD   leal -556(%ebp),%edx
---
>  2596 16b9 8D95D8FD   leal -552(%ebp),%edx
2876c2876
<  2619 172a 8B85D0FD   movl -560(%ebp),%eax
---
>  2619 172a 8B85D4FD   movl -556(%ebp),%eax
3043c3043
<  2725 18fa 8B85D0FD   movl -560(%ebp),%eax
---
>  2725 18fa 8B85D4FD   movl -556(%ebp),%eax
3056c3056
<  2735 1917 89B5D0FD   movl %esi,-560(%ebp)
---
>  2735 1917 89B5D4FD   movl %esi,-556(%ebp)
3074c3074
<  2746 1942 8B85D8FD   movl -552(%ebp),%eax
---
>  2746 1942 8B85DCFD   movl -548(%ebp),%eax
3096c3096
<  2762 197a 8B85D0FD   movl -560(%ebp),%eax
---
>  2762 197a 8B85D4FD   movl -556(%ebp),%eax

--
                                                Greg A. Woods
                                                Planix, Inc.

<woods%planix.com@localhost>       +1 250 762-7675        http://www.planix.com/