Clarify which type "Label" refers to (generic vs X86)

Clarify which type "Label" refers to (generic vs X86)

There is a generic Label that can be used as-is for ARM
and MIPS, and there is an x86 derived class Label which
adds the concept of near and far (for 8-bit vs 32-bit
jumps). Previously, one method "getOrCreateCfgNodeLabel"
would say that it returns a Label when it means the generic
one in some cases and the x86 one in other cases.

Split that into getCfgNodeLabel and getOrCreateCfgNodeLabel
where getCfgNodeLabel returns the generic one and
getOrCreateCfgNodeLabel is part of the x86 code and
returns the x86 one.

BUG=none
R=ascull@google.com, stichnot@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a=commit;h=c2ec58179184e3357255a02b94ec6b219dc44080

[jvoung (off chromium), 2015-07-31 18:22:20]

jvoung@chromium.org changed reviewers:
+ jpp@chromium.org, stichnot@chromium.org

[ascull, 2015-07-31 20:54:54]

ascull@google.com changed reviewers:
+ ascull@google.com

[ascull, 2015-07-31 20:54:54]

https://codereview.chromium.org/1265023003/diff/20001/src/IceAssembler.h
File src/IceAssembler.h (right):

https://codereview.chromium.org/1265023003/diff/20001/src/IceAssembler.h#newc...
src/IceAssembler.h:37: class LabelBase {
Given that ARM and MIPS won't extend this is and that it is not abstract it
would make more sense for this to stay being called Label and for the name to
change in the specialization.

[jvoung (off chromium), 2015-08-03 17:19:21]

https://codereview.chromium.org/1265023003/diff/20001/src/IceAssembler.h
File src/IceAssembler.h (right):

https://codereview.chromium.org/1265023003/diff/20001/src/IceAssembler.h#newc...
src/IceAssembler.h:37: class LabelBase {
On 2015/07/31 20:54:54, ascull wrote:
> Given that ARM and MIPS won't extend this is and that it is not abstract it
> would make more sense for this to stay being called Label and for the name to
> change in the specialization.


Hmm good point about "Base"... ARM and MIPS don't distinguish between Near/Far
so it didn't need the extension.

I wasn't too excited about changing X86 to something other than "Label" if ARM
and MIPS were assemblers/assembler tests were going to simply use "Label" in
their namespace. Then the assemblers would have more similarity, modulo the
namespace. Otherwise, if folks feel strongly and do want to call the X86 version
something else, I'd prefer to come up with a name before I go off and change a
bunch of files =)

For now, I've reverted LabelBase to Label, kept the x86 version as
Ice::X86Internal::Label, and kept the split of getCfgNodeLabel() vs
getOrCreateCfgNodeLabel(), since sometimes getOrCreateCfgNodeLabel()'s return
type is expected to be Ice::X86Internal::Label instead of Ice::Label, while
getCfgNodeLabel() return type is expected to be Ice::Label.

https://codereview.chromium.org/1265023003/diff/40001/src/IceAssemblerX8632.h
File src/IceAssemblerX8632.h (right):

https://codereview.chromium.org/1265023003/diff/40001/src/IceAssemblerX8632.h...
src/IceAssemblerX8632.h:41: using Label = ::Ice::X86Internal::Label;
I think this was actually the only line needed to make the unit tests compile
again, but thought it would be good to clarify which label is which.

[ascull, 2015-08-04 17:37:28]

lgtm

[Jim Stichnoth, 2015-08-05 13:14:19]

lgtm

[jvoung (off chromium), 2015-08-05 16:13:31]

updated CL description --

Also the unittest appears to be compiling again, independently of this change. I
believe thanks to John's change here:
https://codereview.chromium.org/1257643004/diff/120001/unittest/AssemblerX863...

[jvoung (off chromium), 2015-08-05 16:35:42]

Committed patchset #3 (id:40001) manually as
c2ec58179184e3357255a02b94ec6b219dc44080 (presubmit successful).