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David Daney wrote:
Daniel Jacobowitz wrote:
While stuck offline earlier today, I revisited the textrel-1 MIPS failure. Eric originally tried setting DF_TEXTREL during section relocation, but it's too late: we add the entry in size_dynamic_sections. But I couldn't see any other way to get it right, since there's no hook to predict whether elf-eh-frame.c will eliminate a relocation.
The easiest approach I found was to annul the DT_TEXTREL and DT_FLAGS changes in finish_dynamic_sections if no text relocations were actually generated. This is not immensely pretty, but does work. OK?
For background, the problem arises from the use of absolute addresses in .eh_frame. In this case, they're being produced by gas CFI directives. Is there a reason we can't mix and match encodings? i.e. why not have gas use a PC-relative format? I'm sure there's a reason, but I can't think of it...
Could it be related to the reason that GCC no longer generates a PC-relative .eh_frame?
I never fully understood the reason, but I think it has to do with MIPS-ELF specifications not allowing the needed relocation types (even though they work well in binutils/glibc/linux).
The needed relocation types were originally defined for embedded PIC MIPS and are not available in the ABI spec, their use for eh_frame was an accident. When the removal of embedded PIC support broke the toolchain, the fix chosen was to become ABI compatible again.
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