Remove unsused variables.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221834 91177308-0d34-0410-b5e6-96231b3b80d8
Allow DWARFFormValue::extractValue to be called with a null CU.

Currently FormValues are only used for attributes of DIEs and thus
uers always have a CU lying around when calling into the FormValue
API.
Accelerator tables encode their information using the same Forms
as the attributes, thus it is natural to use DWARFFormValue to
extract/dump them. There is no CU in that case though. Allow the
API to be called with a null CU arguemnt by making the RelocMap
lookup conditional on the CU pointer validity. And document this
new behvior in the header. (Test coverage for this use of the API
comes in the DwarfAccelTable support patch)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221835 91177308-0d34-0410-b5e6-96231b3b80d8
[dwarfdump] Add support for dumping accelerator tables.

The class used for the dump only allows to dump for the moment, but
it can (and will) be easily extended to support search also.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221836 91177308-0d34-0410-b5e6-96231b3b80d8
Fix emission of Dwarf accelerator table when there are multiple CUs.

The DIE offset in the accel tables is an offset relative to the start
of the debug_info section, but we were encoding the offset to the
start of the containing CU.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221837 91177308-0d34-0410-b5e6-96231b3b80d8
Teach ScalarEvolution to sharpen range information.

If x is known to have the range [a, b), in a loop predicated by (icmp
ne x, a) its range can be sharpened to [a + 1, b).  Get
ScalarEvolution and hence IndVars to exploit this fact.

This change triggers an optimization to widen-loop-comp.ll, so it had
to be edited to get it to pass.

This change was originally landed in r219834 but had a bug and broke
ASan. It was reverted in r219878, and is now being re-landed after
fixing the original bug.

phabricator: http://reviews.llvm.org/D5639
reviewed by: atrick



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221839 91177308-0d34-0410-b5e6-96231b3b80d8
[Bitcode] AtEndOfStream should only check against the size if it's known.

This avoids an issue where AtEndOfStream mistakenly returns true at the /start/ of
a stream.

(In the rare case that the size is known and actually 0, the slow path will still
handle it correctly.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221840 91177308-0d34-0410-b5e6-96231b3b80d8
Improve long path name support on Windows.

Windows normally limits the length of an absolute path name to 260
characters; directories can have lower limits.  These limits increase
to about 32K if you use absolute paths with the special '\\?\'
prefix. Teach Support\Windows\Path.inc to use that prefix as needed.

TODO: Other parts of Support could also learn to use this prefix.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221841 91177308-0d34-0410-b5e6-96231b3b80d8
Revert "[dwarfdump] Add support for dumping accelerator tables."

This reverts commit r221836.

The tests are asserting on some buildbots. This also reverts the
test part of r221837 as it relies on dwarfdump dumping the
accelerator tables.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221842 91177308-0d34-0410-b5e6-96231b3b80d8