[PATCH] D88076: [llvm-readelf/obj] - Stop printing wrong addresses for arm32 unwind info for non-relocatable objects.

[George Rimar via Phabricator via llvm-commits]

grimar created this revision.
grimar added reviewers: jhenderson, MaskRay, psmith, rprichard.
Herald added subscribers: rupprecht, kristof.beyls, emaste.
Herald added a reviewer: espindola.
Herald added a project: LLVM.
grimar requested review of this revision.

This is the first patch for https://bugs.llvm.org/show_bug.cgi?id=47581.

Currently -u does not compute function addresses correctly and
dumps broken addresses for non-relocatable objects.

ARM spec says:
"An index table entry consists of 2 words.
The first word contains a prel31 offset (see Relocations) to the start of a function, with bit 31 clear."
...
"The relocated 31 bits form a place-relative signed offset to the referenced entity.
For brevity, this document will refer to the results of these relocations as "prel31 offsets"."

(https://developer.arm.com/documentation/ihi0038/c/?lang=en#index-table-entries)
(https://developer.arm.com/documentation/ihi0038/c/?lang=en#relocations)

Currently we use an address of the SHT_ARM_EXIDX section instead of an address of an entry
in computations. As a result we compute an offset that is not really "place-relative",
but section relative, what is wrong.

The patch fixes this issue.


https://reviews.llvm.org/D88076

Files:
  llvm/test/tools/llvm-readobj/ELF/ARM/unwind-non-relocatable.test
  llvm/tools/llvm-readobj/ARMEHABIPrinter.h

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