Re: RFC: linkage patch to mips.c

[Jim Wilson <wilson at redhat dot com>]

Speaking of MIPS ABI problems, Red Hat assigned me to look at and try to fix
a known MIPS ABI problem, the Irix6 N32 small structure argument problem.  Gdb
has its own ABI implementation for inferior function calls, and has some
decent testsuite support for testing them.  This serves as a good ABI test for
gcc, since it tests compatibility between the gdb and gcc code.  So I tried
running the gdb testsuite, and discovered that there are more MIPS ABI problems
then I knew about.  I am still looking for ABI bugs, so I might find more, but
here is my current list of issues.
1) LE O32, small structures in argument registers are left-justified instead of
   right-justified
2) BE N32/N64, small structures in argument registers are right-justified
   instead of left-justified
3) all BE ABIs, small structure arguments in stack slots are padded downward
   (right-justified) instead of padded upward (left-justified).

Jim