Bug #9665: Ruby 2.1.1 fails to build on PowerPC darwin, due to __builtin_unreachable

• Status: Closed
• Assignee: macos
• Target version: 2.2.0
• ruby -v: ruby 2.1.1p76 (2014-02-24 revision 45161) [powerpc-darwin8.0]
• Backport: 2.0.0: DONE, 2.1: DONE

[mistydemeo (Misty De Meo)]

Ruby 2.1.1 (and possibly a few older versions) fails to build on PowerPC Darwin using Apple-provided GCCs. When linking miniruby, the build fails due to:

/usr/libexec/gcc/powerpc-apple-darwin8/4.2.1/ld: Undefined symbols:
___builtin_unreachable

This occurs with Apple GCC 4.0 and 4.2, on Mac OS X 10.4 and 10.5 PowerPC. The issue does not occur using newer FSF GCCs (for instance, 4.8.2) on the same OS X versions. While I'm unable to test on 10.5 Intel, I can confirm that newer Intel OS X versions work fine using Apple GCC 4.2.

Verbose build logs, from Mac OS X 10.4 with Apple GCC 4.2, are attached.

While I suspect this was possibly introduced by r34784, as removing the check from configure allows the build to succeed, that revision is 2 years old and I only noticed these build failures beginning relatively recently.

[nobu (Nobuyoshi Nakada)]

• Description updated (diff)
• Target version set to 2.2.0
• Backport set to 2.0.0: REQUIRED, 2.1: REQUIRED

With MacPorts apple-gcc42, __builtin_unreachable seems detected as no, successfully.

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed
• % Done changed from 0 to 100

Applied in changeset r45716.

---

configure.in: refine __builtin_unreachable check

• configure.in (rb_cv_func___builtin_unreachable): try with an
  external variable not only by a warning, which might not be
  shown due to the optimization. [ruby-core:61647] [Bug #9665]

[usa (Usaku NAKAMURA)]

• Backport changed from 2.0.0: REQUIRED, 2.1: REQUIRED to 2.0.0: DONE, 2.1: REQUIRED

backported into ruby_2_0_0 at r46201.

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.0.0: DONE, 2.1: REQUIRED to 2.0.0: DONE, 2.1: DONE

r45716 was backported into ruby_2_1 branch at r46215.