Re: Repeatable builds with Visual C++ ?

[Uwe Schuster]

Johan Holmberg [SMTP:address@hidden wrote:

> I wonder if anyone knows if it is possible to reproduce an exe-file
> "byte-by-byte" with Visual C++.
>
> Visual C++ puts timestamps in the object files, but I think I found
> a way around that by running "dumpbin" on the resulting exe, like
> this:
>        1) remove all object- and exe-files
>        2) compile/link appl. with Cons.
>        3) run "dumpbin /all EXEFILE > EXEFILE.dump-1
>        4) remove all object- and exe-files
>        5) compile/link appl. with Cons.
>        6) run "dumpbin /all EXEFILE > EXEFILE.dump-2
>        7) run "diff EXEFILE.dump-1 EXEFILE.dump-2"
>
> Does anyone know anything about this problem ?


Have a look at the ms-knowledge base article: Q164151 HOWTO: Comparing Binary 
Images of Same Project Builds

You will see, that there are many difficulties and special cases to observe, 
like time-stamps also in ressources, differently linker behaviour between two 
builds (thanks to ms).

We use such a way for comparing our executables, but not with cons. We make the 
builds directly in the VC IDE and then we use a little make script or batch 
file that calls the dumpbin and then call a diff utility to compare with the 
other executable.

// compare exe files
dumpbin /disasm %1.exe >%1.txt
dumpbin /disasm %2.exe >%2.txt
diff %1.txt %2.txt

// compare dll files
dumpbin /RAWDATA %1.dll >%1.txt
dumpbin /headers %1.dll >%1.hdr
dumpbin /RAWDATA %2.dll >%2.txt
dumpbin /headers %2.dll >%2.hdr
diff %1.txt %2.txt
diff %1.hdr %2.hdr

This works fine for us, in the moment, but i think it is not suitable for all 
situations.

Hope that helps.