This implementation is known to work in very simple cases (see new test case).

Differential Revision: http://reviews.llvm.org/D10115

llvm-svn: 238777

Previously, a MemoryBuffer of a file was owned by each InputFile object.
This patch makes the Driver own all of them. InputFiles now have only
MemoryBufferRefs. This change simplifies ownership managment
(particularly for ObjectFile -- the object owned a MemoryBuffer only when
it's not created from an archive file, because in that case a parent
archive file owned the entire buffer. Now it owns nothing unconditionally.)

llvm-svn: 238690

Other local variables shadowed the member variable.
Rename to make that a bit longer.

llvm-svn: 238478

This is an initial patch for a section-based COFF linker.

The patch has 2300 lines of code including comments and blank lines.
Before diving into details, you want to start from reading README
because it should give you an overview of the design.

All important things are written in the README file, so I write
summary here.

- The linker is already able to self-link on Windows.

- It's significantly faster than the existing implementation.
  The existing one takes 5 seconds to link LLD on my machine,
  while the new one only takes 1.2 seconds, even though the new
  one is not multi-threaded yet. (And a proof-of-concept multi-
  threaded version was able to link it in 0.5 seconds.)

- It uses much less memory (250MB vs. 2GB virtual memory space
  to self-host).

- IMHO the new code is much simpler and easier to read than
  the existing PE/COFF port.

http://reviews.llvm.org/D10036

llvm-svn: 238458