Patch continues work started in D24706 and D25821.

in this patch symbol table and constant pool areas were
added to .gdb_index section output.

This one finishes the implementation of --gdb-index functionality in LLD.

Differential revision: https://reviews.llvm.org/D26283

llvm-svn: 289810

Fixed inaccurate member type: uint32_t -> size_t
(http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/2984/steps/build/logs/stdio).

llvm-svn: 289796

(http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/2982)

llvm-svn: 289792

Patch continues work started in D24706,

in this patch address area was added to .gdb_index section output.

Differential revision: https://reviews.llvm.org/D25821

llvm-svn: 289790

In this patch partial gdb_index section is created. 
For costructing the .gdb_index section 6 steps should be performed (details are in
SplitDebugInfo.cpp file header), this patch do first 3:

Creates proper section header.
Fills list of compilation units.
Types CU list area is not supposed to be supported, so it is ignored and therefore
can be treated as implemented either.

Differential revision: https://reviews.llvm.org/D24706

llvm-svn: 284708