[PATCH] D18349: [ELF][MIPS] Reduce number of redundant entries in the local part of MIPS GOT

[Simon Atanasyan via llvm-commits]

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Local symbol which requires GOT entry initialized by "page" address. This address is high 16 bits of sum of the symbol value and the relocation addend. In the relocation scanning phase final values of symbols are unknown so to reduce number of allocated GOT entries do the following trick. Save all output sections referenced by GOT relocations during the relocation scanning phase. Then later in the `GotSection::finalize` method calculate number of "pages" required to cover all saved output sections and allocate appropriate number of GOT entries. We assume that symbols referenced by GOT relocations are spread uniformly among output sections.

Alternative approach might be creation of something like `MipsGotSection`, making some methods of `GotSection` virtuals, and moving all MIPS specific code and data structures into it.

Repository:
  rL LLVM

http://reviews.llvm.org/D18349

Files:
  ELF/OutputSections.cpp
  ELF/OutputSections.h
  ELF/Writer.cpp
  test/ELF/mips-got-redundant.s

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