[Bug lto/44965] New: lto option code breaks file format with each added option

[andi-gcc at firstfloor dot org]

Had the following problem happen:

Create a LTO build of a program with a gcc git checkout
Update to a slightly newer checkout
The new checkout had one option in fortran more added
Continue compiling the program without make clean with the new compiler
LTO link failed with this assert failing:

392 else if (o->type == CL_COMMON) 
393    gcc_assert (option->flag_var);

I think what happened is that the lto-opts code wrote the option
indexes into the object files and with the compiler update and the
new option they all shifted and become different. In my case the assert
happened
because it was trying to set a fortran specific option in a C
build.

There's some version checking in the lto-opts code

memset (&header, 0, sizeof (header));
  header.lto_header.major_version = LTO_major_version;
  header.lto_header.minor_version = LTO_minor_version;
  header.lto_header.section_type = LTO_section_opts;

but LTO_major/minor seems to be always just 1/0, so of course
didn't catch this.


-- 
           Summary: lto option code breaks file format with each added
                    option
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: andi-gcc at firstfloor dot org
  GCC host triplet: x86_64-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44965