1287671 - Simplify jscpucfg.h

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Mike Hommey [:glandium]]

All the supported compilers have __BYTE_ORDER__, except MSVC, which is little-endian-only. So there's a whole bunch of e.g. if defined(JS_HAVE_*) related things that can go away.

Comment 1

[Mike Hommey [:glandium]]

Attachment: Bug 1287671 - Simplify jscpucfg.h.

All the supported compilers to build JS now support __BYTE_ORDER__,
except MSVC, which only supports one kind of endianness. This allows to
drastically simplify jscpucfg.h as a consequence.

Apart from endianness, jscpucfg.h is defining JS_HAVE_LONG_LONG, which
isn't used anywhere, defines a macro for the Watcom C/C++ compiler, and
tries to figure out stack growth direction.

The first is obviously unnecessary. The second is not useful now that
building JS requires a C++11-capable compiler, which the Watcom C/C++
compiler isn't. The latter, however, is still relevant, but the check
based on sys/isa_def.h is, afaict, only relevant on HP-UX on PA-RISC,
which is already covered by the check for __hppa.

Consequently, the various checks setting JS_HAVE_header_H defines can
all be removed.

Review commit: https://reviewboard.mozilla.org/r/65162/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/65162/

Comment 2

[Mike Hommey [:glandium]]

Comment on attachment 8772327 [details]
Bug 1287671 - Simplify jscpucfg.h.

Cancelling after talking with njn who made me realize there's MOZ_{BIG,LITTLE}_ENDIAN and we should just use that, killing most of jscpucfg.h.

Comment 3

[Mike Hommey [:glandium]]

Comment on attachment 8772327 [details]
Bug 1287671 - Simplify jscpucfg.h.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/65162/diff/1-2/

Comment 4

[Nicholas Nethercote [inactive]]

Comment on attachment 8772327 [details]
Bug 1287671 - Simplify jscpucfg.h.

https://reviewboard.mozilla.org/r/65162/#review81618

This is good enough to land, but I'll give you bonus points if you remove the definitions of IS_{BIG,LITTLE}_ENDIAN and replace the handful of uses of them within js/src/ with MOZ_{BIG,LITTLE}_ENDIAN.

Comment 5

[Mike Hommey [:glandium]]

Heh, I thought there were more than there actually are, I'll add a patch doing that.

Comment 6

[Mike Hommey [:glandium]]

Attachment: Bug 1287671 - Replace IS_{LITTLE|BIG}_ENDIAN with MOZ_{LITTLE|BIG}_ENDIAN in js/.

Review commit: https://reviewboard.mozilla.org/r/82976/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/82976/

Comment 7

[Nicholas Nethercote [inactive]]

Comment on attachment 8797376 [details]
Bug 1287671 - Replace IS_{LITTLE|BIG}_ENDIAN with MOZ_{LITTLE|BIG}_ENDIAN in js/.

https://reviewboard.mozilla.org/r/82976/#review81656

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/50f9b4a613b0
Simplify jscpucfg.h. r=njn
https://hg.mozilla.org/integration/autoland/rev/1c4f0a3784f1
Replace IS_{LITTLE|BIG}_ENDIAN with MOZ_{LITTLE|BIG}_ENDIAN in js/. r=njn

Comment 9

[Iris Hsiao [:ihsiao]]

Backed out for jit-test bustages, i.e., https://treeherder.mozilla.org/logviewer.html#?job_id=4419482&repo=autoland#L1192 and https://treeherder.mozilla.org/logviewer.html#?job_id=4423143&repo=autoland#L5120

Comment 10

[Mike Hommey [:glandium]]

Fun things are fun, when MOZ_LITTLE_ENDIAN is defined to 1, MOZ_BIG_ENDIAN is defined to 0, contrary to IS_BIG_ENDIAN, which was #undef'ed.

Comment 11

[Pulsebot]

Backout by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e548982279e2
Backed out changeset 1c4f0a3784f1 for jit-test bustages
https://hg.mozilla.org/integration/autoland/rev/114ae8fb1a77
Backed out changeset 50f9b4a613b0

Comment 12

[Mike Hommey [:glandium]]

Comment on attachment 8797376 [details]
Bug 1287671 - Replace IS_{LITTLE|BIG}_ENDIAN with MOZ_{LITTLE|BIG}_ENDIAN in js/.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/82976/diff/1-2/

Comment 13

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a9bac26b17a4
Simplify jscpucfg.h. r=njn
https://hg.mozilla.org/integration/autoland/rev/b232aaced78a
Replace IS_{LITTLE|BIG}_ENDIAN with MOZ_{LITTLE|BIG}_ENDIAN in js/. r=njn

Comment 14

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/a9bac26b17a4
https://hg.mozilla.org/mozilla-central/rev/b232aaced78a