Hardware-optimized compiler flags

[mmoelle1]

Output of brew config

HOMEBREW_VERSION: 4.1.3-6-g1b6c46f
ORIGIN: https://github.com/Homebrew/brew
HEAD: 1b6c46ff12aace0f268303888ecd5495c95bdeaa
Last commit: 2 hours ago
Core tap origin: https://github.com/Homebrew/homebrew-core
Core tap HEAD: 15226c71101b2667901a78316fc97e120ebcf9d9
Core tap last commit: 43 seconds ago
Core tap branch: gismo
Core tap JSON: 31 Jul 19:16 UTC
HOMEBREW_PREFIX: /opt/homebrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_DISPLAY: /private/tmp/com.apple.launchd.7A54xKsbYG/org.xquartz:0
HOMEBREW_MAKE_JOBS: 8
Homebrew Ruby: 2.6.10 => /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/ruby
CPU: octa-core 64-bit arm_firestorm_icestorm
Clang: 14.0.3 build 1403
Git: 2.39.2 => /Library/Developer/CommandLineTools/usr/bin/git
Curl: 7.88.1 => /usr/bin/curl
macOS: 13.4.1-arm64
CLT: 14.3.1.0.1.1683849156
Xcode: N/A
Rosetta 2: false

Output of brew doctor

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Warning: Unbrewed dylibs were found in /usr/local/lib.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.

Unexpected dylibs:
  /usr/local/lib/libomp.dylib

Warning: Unbrewed header files were found in /usr/local/include.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.

Unexpected header files:
  /usr/local/include/omp-tools.h
  /usr/local/include/omp.h
  /usr/local/include/ompt.h

Warning: Unbrewed static libraries were found in /usr/local/lib.
If you didn't put them there on purpose they could cause problems when
building Homebrew formulae, and may need to be deleted.

Unexpected static libraries:
  /usr/local/lib/libomp.a

Warning: Some taps are not on the default git origin branch and may not receive
updates. If this is a surprise to you, check out the default branch with:
  git -C $(brew --repo homebrew/core) checkout master

Description of issue

I have created a new formula for the open-source G+Smo library. The library supports CPU-optimized compilation. I tried to adopt the strategy from the openblas formula, i.e.

args << case Hardware.oldest_cpu
when :arm_vortex_tempest
  "-DTARGET_ARCHITECTURE=apple-m1"
else
  "-DTARGET_ARCHITECTURE=" << Hardware.oldest_cpu.upcase.to_s
end

but brew audit --strict gismo gives me the error message

Formulae should be verified as having support for runtime hardware detection before using ENV.runtime_cpu_detection.

Any help on this issue is appreciated.

[osalbahr]

Looking at the source code of the audit:

          find_instance_method_call(body_node, "ENV", :runtime_cpu_detection) do
            next if tap_style_exception? :runtime_cpu_detection_allowlist

            problem "Formulae should be verified as having support for runtime hardware detection before " \
                    "using ENV.runtime_cpu_detection."
          end

Did you add the formula to runtime_cpu_detection_allowlist.json?

[osalbahr]

Not sure. Does the following work? (it probably doesn't).

on_macos do
  on_arm do
    args << "-DTARGET_ARCHITECTURE=apple-m1"
  end
end

on_intel do
    args << "-DTARGET_ARCHITECTURE=penryn"
end

Edit: that'd probably do it. See glibc.rb#L67.

[osalbahr]

If on_* are boolean values (not sure if they are) then perhaps you can use them in if statements under def install (even if it works it'd probably be an unconventional formula style).

[mmoelle1]

Thanks for your help. I think that I finally found an elegant way (thanks to your help and the output of brew audit --strict gismo):

if OS.mac?
  args << "-DTARGET_ARCHITECTURE=apple-m1" if Hardware::CPU.arm?
  args << "-DTARGET_ARCHITECTURE=penryn"   if Hardware::CPU.intel?
elsif OS.linux?
  args << "-DTARGET_ARCHITECTURE=penryn"   if Hardware::CPU.intel?
end

Are there any other OS/ARCH combinations that should be supported? E.g. linux/arm?

[osalbahr]

I think Homebrew currently supports macOS intel/arm and Linux intel if that's what you're asking.

[mmoelle1]

Yes, that's exactly what I meant. Thank you!

[osalbahr]

You’re welcome! I’d like to also add that some formulae aren’t available in all platforms, it depends.