Allow temporary overrides of error stream in NaClBitcodeParser.

Allow temporary overrides of error stream in NaClBitcodeParser.

Generalizes method setErrStream to return old error stream, so that
one can temporarily replace the error stream, and replace it to its
old value afterwards.

BUG=None
R=stichnot@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-llvm.git;a=commit;h=5d49470871746ecf649ad496f1706fbb1b548207

[Karl, 2015-01-22 17:06:58]

kschimpf@google.com changed reviewers:
+ jvoung@chromium.org

[Karl, 2015-01-22 17:17:18]

kschimpf@google.com changed reviewers:
+ stichnot@chromium.org

[Jim Stichnoth, 2015-01-22 17:26:13]

https://codereview.chromium.org/865963002/diff/1/include/llvm/Bitcode/NaCl/Na...
File include/llvm/Bitcode/NaCl/NaClBitcodeParser.h (right):

https://codereview.chromium.org/865963002/diff/1/include/llvm/Bitcode/NaCl/Na...
include/llvm/Bitcode/NaCl/NaClBitcodeParser.h:471: // Changes the stream to
print errors to. There are two use cases:
Just to be clear for the short-of-attention-span, add a note in the first
sentence saying it returns the old stream.

https://codereview.chromium.org/865963002/diff/1/include/llvm/Bitcode/NaCl/Na...
include/llvm/Bitcode/NaCl/NaClBitcodeParser.h:479: raw_ostream
*setErrStream(raw_ostream &Stream) {
It seems a little odd to mix raw_ostream* and raw_ostream&.  Would it be
reasonable to return raw_ostream& instead?

[Karl, 2015-01-22 17:42:58]

https://codereview.chromium.org/865963002/diff/1/include/llvm/Bitcode/NaCl/Na...
File include/llvm/Bitcode/NaCl/NaClBitcodeParser.h (right):

https://codereview.chromium.org/865963002/diff/1/include/llvm/Bitcode/NaCl/Na...
include/llvm/Bitcode/NaCl/NaClBitcodeParser.h:471: // Changes the stream to
print errors to. There are two use cases:
On 2015/01/22 17:26:13, stichnot wrote:
> Just to be clear for the short-of-attention-span, add a note in the first
> sentence saying it returns the old stream.

Done.

https://codereview.chromium.org/865963002/diff/1/include/llvm/Bitcode/NaCl/Na...
include/llvm/Bitcode/NaCl/NaClBitcodeParser.h:479: raw_ostream
*setErrStream(raw_ostream &Stream) {
On 2015/01/22 17:26:13, stichnot wrote:
> It seems a little odd to mix raw_ostream* and raw_ostream&.  Would it be
> reasonable to return raw_ostream& instead?

Done.

[Jim Stichnoth, 2015-01-22 17:56:59]

lgtm

[Karl, 2015-01-22 17:58:27]

Committed patchset #3 (id:40001) manually as
5d49470871746ecf649ad496f1706fbb1b548207 (presubmit successful).