commit 31d5cdbe7714d545c7513b2587f56045f7ff3efb
author Alex Bradbury <asb@lowrisc.org> Thu Jul 18 05:22:55 2019 +0000
committer Alex Bradbury <asb@lowrisc.org> Thu Jul 18 05:22:55 2019 +0000
tree b703ab9913ec04fa0774f062da61f15875fffa65
parent b882c8bae390b434129cff6acbf6ae7dff63ac69

[DWARF][RISCV] Add support for RISC-V relocations needed for debug info

When code relaxation is enabled many RISC-V fixups are not resolved but
instead relocations are emitted. This happens even for DWARF debug
sections. Therefore, to properly support the parsing of DWARF debug info
we need to be able to resolve RISC-V relocations. This patch adds:

* Support for RISC-V relocations in RelocationResolver
* DWARF support for two relocations per object file offset
* DWARF changes to support relocations in more DIE fields

The two relocations per offset change is needed because some RISC-V
relocations (used for label differences) come in pairs.

Relocations can also be emitted for DWARF fields where relocations were
not yet evaluated. Adding relocation support for some of these fields is
essencial. On the other hand, LLVM currently emits RISC-V relocations
for fixups that could be safely evaluated, since they can never be
affected by code relaxations. This patch also adds relocation support
for the fields affected by those extraneous relocations (the DWARF unit
entry Length, and the DWARF debug line entry TotalLength and
PrologueLength), for testing purposes.

Differential Revision: https://reviews.llvm.org/D62062
Patch by Luís Marques.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@366402 91177308-0d34-0410-b5e6-96231b3b80d8