[PATCH] D18795: Don't store names in the symbols

[Rafael Ávila de Espíndola via llvm-commits]

rafael created this revision.
rafael added a reviewer: ruiu.
rafael added a subscriber: llvm-commits.

Most of the linker doesn't have to handle symbol names. The parts that do are close enough to the symbol table that they can get the name from there.

This deletes the boilerplate for tracking whether we have a name or name offset. It also reduces SymbolBody from 56 to 40 bytes on x86_64.

The performance results are more mixed than what I was expecting, but I think the patch is still worth it:


the gold plugin
  master 0.389837796
  patch  0.390047270
clang
  master 0.669623963
  patch  0.666252931
llvm-as
  master 0.035799643
  patch  0.035869600
the gold plugin fsds
  master 0.417012576
  patch  0.415979779
clang fsds
  master 0.722732074
  patch  0.719288980
llvm-as fsds
  master 0.032511485
  patch  0.032528634
scylla
  master 4.915247943
  patch  4.978490188


http://reviews.llvm.org/D18795

Files:
  ELF/InputFiles.cpp
  ELF/InputFiles.h
  ELF/OutputSections.cpp
  ELF/OutputSections.h
  ELF/SymbolTable.cpp
  ELF/SymbolTable.h
  ELF/Symbols.cpp
  ELF/Symbols.h
  ELF/Writer.cpp

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