[PECOFF][Writer] s/dyn_cast/cast/ where we don't expect null return value.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@186353 91177308-0d34-0410-b5e6-96231b3b80d8
[PECOFF][Writer] Follow up patch for r186336.

- Make a const reference instead of copying an object
- Fix a comment

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@186355 91177308-0d34-0410-b5e6-96231b3b80d8
Revert "Don't pass llvm::errs() all over the place. Diagnostics always go to stderr."

This reverts commit 185657. It will be used by unit tests.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@186366 91177308-0d34-0410-b5e6-96231b3b80d8
[PECOFF] Add default argument to addDir32NBReloc() as the default value 0 is reasonable.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@186368 91177308-0d34-0410-b5e6-96231b3b80d8
[PECOFF][Writer] Use defined constants instead of magic numbers.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@186382 91177308-0d34-0410-b5e6-96231b3b80d8
[PECOFF][Writer] Replace magic numbers with sizeof().

This is a follow up patch for r186336.

Reviewers: LegalizeAdulthood

CC: silvas, llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1144

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@186384 91177308-0d34-0410-b5e6-96231b3b80d8