[llvm-commits] [PATCH] ARM/MC/ELF e_flags fixup - add an ARMMCCodeEmitterBase class?

[Jason Kim]

Hi everyone,

With some chagrin, I discovered that the existing ARM/GNU tool chain
requires a non-zero ELF e_flags field.
Specifically, a nonzero value between 4 and 5 for the EF_ARM_EABIMASK

Without this field, none of the ELF .o files link properly!

Adding it in is easy enough to do, but the right place to do this
seems to be within ARMSubtarget, which is problematic.
So the workaround is to add a small ARMMCCodeEmitterBase class to hold
the e_flags value to be emitted.

I can just as easily just hack this in within ARMELFObjectWriter, but
this seems to be messier, as I can forsee different values being
emitted depending on which ABI version LLVM should emit code for -
which seems to belong in ARMSubtarget (which is hidden from the MC
backend ...)

In any case, some form of this flag value needs to be emitted.
Otherwise none of the ELF .o files will be linkable with existing
tools (!)

Is it OK to add in this class? Is there a better place to put this
flag? Should I just hardcode in 5 (which is current, but existing
tools seem to like 4 too.)?

Thanks!

-jason
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