Multiple inheritance thunks on ARM

Multiple inheritance thunks on ARM

[Roland Franks]

When I try and compile a largish C++ application which contains examples of
multiple inheritance for an ARM processor running in thumb mode I end up
with code that cannot be linked (with many errors of the form "relocation
truncated to fit: R_ARM_THM_PC11 ....."). This appears to be because the
thunks generated for multiply inherited classes are in a different sections
to the destination function and jump to that function via a 'b' instruction
(which has an 11 bit target offset). In a largish application the thunk and
the destination function are too far apart for this relocation to be
resolved.

The problem can be fixed by modifying the compiler and substituting a "bl"
instruction for the "b" instruction in the macro ASM_OUTPUT_MI_THUNK. I
would however, prefer not to change the compiler - does anyone have any
suggestions ?

GCC is version 3.0.2.

Regards.


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