Getting a formula (isl) to use current version of GCC, and building gcc on High Sierra from now on

[Jerry1144]

With isl hitting version 0.25, it now uses C++17 features and fails to build on High Sierra, whose CLT10.14 clang correctly reports that this is not supported on this 10.13 system:

./configure --prefix=/usr/local/Cellar/isl/0.25 --with-gmp=system --with-gmp-prefix=/usr/local/opt/gmp
make
(snip)
clang++ -std=c++11 -std=gnu++17 -DHAVE_CONFIG_H   -I. -I. -I./include -Iinclude/ -I/usr/local/opt/gmp/include   -g -O2 -c -o isl_test_cpp17.o isl_test_cpp17.cc
In file included from isl_test_cpp17-checked.cc:23:
./isl_test_cpp17-generic.cc:48:16: error: call to unavailable member function 'value': introduced in macOS 10.14
        if (maybe_int.value() != 5)
            ~~~~~~~~~~^~~~~
/Library/Developer/CommandLineTools/usr/include/c++/v1/optional:942:27: note: candidate function has been explicitly made unavailable
    constexpr value_type& value() &
                          ^
/Library/Developer/CommandLineTools/usr/include/c++/v1/optional:933:33: note: candidate function has been explicitly made unavailable
    constexpr value_type const& value() const&
                                ^
/Library/Developer/CommandLineTools/usr/include/c++/v1/optional:951:28: note: candidate function not viable: no known conversion from 'optional<...>' to 'optional<...>' for object argument
    constexpr value_type&& value() &&
                           ^
/Library/Developer/CommandLineTools/usr/include/c++/v1/optional:960:34: note: candidate function not viable: no known conversion from 'optional<...>' to 'const optional<...>' for object argument
    constexpr value_type const&& value() const&&
                                 ^
(same error also occurs in isl_test_cpp17-checked.cc, which gets compiled next)

Naturally I tried to assign a C++17-compatible compiler at this formula. However, this update coincided with gcc upgrading to 12.1.0, which unfortunately depends on isl by itself… So I need to somehow make do with the gcc 11.3.0_1 I currently have installed. I'm asking for help for modifying Formula/isl.rb, so that it compiles with minimal interference for all future upgrades. I want to add a build dependency block for High Sierra and below.

Section break

I now report what I have tried.

My version is migrated to gcc@11 at version 11.3.0, so I brew unlink gcc, renamed Cellar/gcc/ to Cellar/gcc@11/ and then Cellar/gcc@11/11.3.0_1/ to Cellar/gcc@11/11.3.0/, and finally brew link gcc@11 made a symlink from gcc@11/11.3.0 to gcc/11.3.0_1 because moving the executables broke them.

• Passing --cc=gcc-11 directly (viz. brew install isl --cc=gcc-11): Success. But then I'll have to keep this old version of gcc around, or symlink the newest gcc every time, because brew upgrade keeps previous install options.
• Passing --cc=gcc: Failure. Enigmatically, this doesn't require me to upgrade my gcc first. It still fails for compiler not supporting C++17's optionals (the same errors I pasted above), so it's probably not using Homebrew's gcc.
• Adding depends_on "gcc@11" => :build to isl.rb: Failure in all circumstances below for the same error. Apparently the gcc it found was still the alias to system clang
  • Upgrading directly
  • Setting CC=gcc in the interactive build environment
  • Passing --cc=gcc
• Adding depends_on "gcc" => :build instead: Failure. This time Homebrew wants to upgrade gcc first, which causes a circular dependency: ==> Installing dependencies for isl: gcc ==> Installing isl dependency: gcc ==> Installing dependencies for gcc: isl ==> Installing gcc dependency: isl ==> Installing dependencies for isl: gcc ==> Installing isl dependency: gcc (snip) ^C
  • Pulling out the old gcc.rb file matching my installed version, so that brew doesn't hit this circular dependency bug: Failure with the same C++17 unsupported error.

All in all, the simplest way to solve this - adding a dependency block - doesn't seem to work, nor does the un-versioned --cc=gcc option. I don't like the working way left, so I'm asking for help.

Section break

For all the unfortunate souls stuck on High Sierra, who don't have any version of Homebrew's gcc yet, so can't even get the first gcc installed, here's a solution - pull out an old version of isl's formula and install it first (I suppose you have dev tools already):

brew update         # Just to minimize the chance the formula gets updated in the mean time
cd "$(brew --repository homebrew/core)"
git checkout 912df90f851785d85995ea89db3ce125d7f4114e -- Formula/isl.rb         # This reverts to isl 0.24 which can be compiled with system clang
brew install isl
brew install gcc@11         # It's a long long build
git checkout master -- Formula/isl.rb         # Get the newest formula back
brew install isl --cc=gcc-11         # I hope some day we can pass --cc=gcc here, but not now
brew install gcc        # now you get the latest gcc

[carlocab]

One other possibility is to brew install llvm and then pass --cc=llvm_clang when building ISL and/or GCC.

[johhnry]

On High Sierra / macOS 10.13 too, I can't install LLVM because it tries to install z3: z3 cannot be built with any available compilers, Install GNU's GCC: brew install gcc

But then I can't install gcc because I can't install isl ^^

What can I do?

[fengerzh]

You can try this: https://github.com/orgs/Homebrew/discussions/4949#discussioncomment-7799075 I followed by installing llvm 12 first, then modify llvm 17 source code, and install successfully.

[nhwebforge]

Argh I feel like everthing I try seems like it's going to work and then another error. @patrikaxelsson your idea is great but when I try to install GCC 11 ignoring the dependencies, it trys to patch it using "Applying gcc-11.4.0.diff", which in turn returns the error:

checking for isl 0.15 or later... no
required isl version is 0.15 or later
configure: error: Unable to find a usable isl.  See config.log for details.

Any ideas how to force an install of 11.0 and not patch to 11.4 - basically ignore the .diff file?

Thanks in advance

[patrikaxelsson]

@nhwebforge: Your attempt shows that the reason I could install gcc@11 without dependencies was because I already had the older isl 0.24 installed. So if there is a way to install the older isl 0.24, it should enable you to install gcc@11.

[konnano]

Save it as you will rewrite (delete) the formula.

cp $(brew --repo)/Library/Taps/homebrew/homebrew-core/Formula/g/gcc.rb ~/gcc.rb

brew edit gcc # disable isl

# depends_on "isl" # Comment line 52

--with-isl=#{Formula["isl"].opt_prefix} # Delete line 98

brew install gcc

brew install --cc=gcc-13 isl

[Bo98]

Hmm, these parts should be optional. C++17 is only used for tests. We should probably look into ways around that.

[Bo98]

Passing ax_cv_cxx_compile_cxx17=no to configure could work as a hack.

[Jerry1144]

Tried a fails_with :clang block. This time brew correctly called the only gcc available without me even specifying a depends_on.

Will open a PR.

[Jerry1144]

Or not, if we can get around this.

[markusbkk]

How do I need to edit the formula (i e brew edit isl) to make the build use the homebrew installed LLVM/Clang?

I followed the directions on this Stackoverflow thread and have a functioning LLVM 13 installation with C++17 support.

[konnano]

llvm@15 is required for isl builds on 10.13
The installation method of llvm@15 is the same

/usr/local/Homebrew/Library/Homebrew/shims/super/cc on line 80

"#{ENV["HOMEBREW_PREFIX"]}/opt/llvm/bin/#{Regexp.last_match(1)}"

rewrite this as

"#{ENV["HOMEBREW_PREFIX"]}/opt/llvm@15/bin/#{Regexp.last_match(1)}"

brew install --cc=llvm_clang isl

[carlocab]

Try this:

diff --git a/Formula/isl.rb b/Formula/isl.rb
index 474fb6ba3d3..1a5cf51c437 100644
--- a/Formula/isl.rb
+++ b/Formula/isl.rb
@@ -37,6 +37,7 @@ class Isl < Formula
   depends_on "gmp"
 
   def install
+    ENV["ax_cv_cxx_compile_cxx17"] = "no"
     system "./autogen.sh" if build.head?
     system "./configure", "--disable-dependency-tracking",
                           "--disable-silent-rules",

You might be able to build isl without needing to install llvm@*.

[markusbkk]

llvm@15 is required for isl builds on 10.13 The installation method of llvm@15 is the same

/usr/local/Homebrew/Library/Homebrew/shims/super/cc on line 80

"#{ENV["HOMEBREW_PREFIX"]}/opt/llvm/bin/#{Regexp.last_match(1)}"

rewrite this as

"#{ENV["HOMEBREW_PREFIX"]}/opt/llvm@15/bin/#{Regexp.last_match(1)}"

brew install --cc=llvm_clang isl

Thanks! I followed these instructions and upgraded to LLVM 15 (exported the path in ~/.profile, too).

Unfortunately, even after rewriting the shim to "#{ENV["HOMEBREW_PREFIX"]}/opt/llvm@15/bin/#{Regexp.last_match(1)}" I receive error: C compiler cannot create executables

[markusbkk]

Try this:

diff --git a/Formula/isl.rb b/Formula/isl.rb
index 474fb6ba3d3..1a5cf51c437 100644
--- a/Formula/isl.rb
+++ b/Formula/isl.rb
@@ -37,6 +37,7 @@ class Isl < Formula
   depends_on "gmp"
 
   def install
+    ENV["ax_cv_cxx_compile_cxx17"] = "no"
     system "./autogen.sh" if build.head?
     system "./configure", "--disable-dependency-tracking",
                           "--disable-silent-rules",

You might be able to build isl without needing to install llvm@*.

Tried that, as well. Doesn't work. I think there's a lot more than just C++17 support that keeps isl from compiling on old versions of Clang.

I really wonder why the installation with cc=llvm_clang reports a non-functioning C compiler though. I'm already compiling my own software with it and it definitely works.

[Jerry1144]

I really wonder why the installation with cc=llvm_clang reports a non-functioning C compiler though. I'm already compiling my own software with it and it definitely works.

Homebrew does not select llvm_clang in any means (we have --cc=gcc-13 but only an unversioned --cc=llvm_clang), instead takes whatever /usr/local/opt/llvm points to. I would ln -s ./llvm@15 /usr/local/opt/llvm to select llvm@15, or ln -s /usr/local/Cellar/llvm/17.0.5 /usr/local/opt/llvm to select the current llvm at version 17.0.5.

[fengerzh]

With isl hitting version 0.25, it now uses C++17 features and fails to build on High Sierra, whose CLT10.14 clang correctly reports that this is not supported on this 10.13 system:

./configure --prefix=/usr/local/Cellar/isl/0.25 --with-gmp=system --with-gmp-prefix=/usr/local/opt/gmp
make
(snip)
clang++ -std=c++11 -std=gnu++17 -DHAVE_CONFIG_H   -I. -I. -I./include -Iinclude/ -I/usr/local/opt/gmp/include   -g -O2 -c -o isl_test_cpp17.o isl_test_cpp17.cc
In file included from isl_test_cpp17-checked.cc:23:
./isl_test_cpp17-generic.cc:48:16: error: call to unavailable member function 'value': introduced in macOS 10.14
        if (maybe_int.value() != 5)
            ~~~~~~~~~~^~~~~
/Library/Developer/CommandLineTools/usr/include/c++/v1/optional:942:27: note: candidate function has been explicitly made unavailable
    constexpr value_type& value() &
                          ^
/Library/Developer/CommandLineTools/usr/include/c++/v1/optional:933:33: note: candidate function has been explicitly made unavailable
    constexpr value_type const& value() const&
                                ^
/Library/Developer/CommandLineTools/usr/include/c++/v1/optional:951:28: note: candidate function not viable: no known conversion from 'optional<...>' to 'optional<...>' for object argument
    constexpr value_type&& value() &&
                           ^
/Library/Developer/CommandLineTools/usr/include/c++/v1/optional:960:34: note: candidate function not viable: no known conversion from 'optional<...>' to 'const optional<...>' for object argument
    constexpr value_type const&& value() const&&
                                 ^
(same error also occurs in isl_test_cpp17-checked.cc, which gets compiled next)

Naturally I tried to assign a C++17-compatible compiler at this formula. However, this update coincided with gcc upgrading to 12.1.0, which unfortunately depends on isl by itself… So I need to somehow make do with the gcc 11.3.0_1 I currently have installed. I'm asking for help for modifying Formula/isl.rb, so that it compiles with minimal interference for all future upgrades. I want to add a build dependency block for High Sierra and below.

Section break

I now report what I have tried.

My version is migrated to gcc@11 at version 11.3.0, so I brew unlink gcc, renamed Cellar/gcc/ to Cellar/gcc@11/ and then Cellar/gcc@11/11.3.0_1/ to Cellar/gcc@11/11.3.0/, and finally brew link gcc@11 made a symlink from gcc@11/11.3.0 to gcc/11.3.0_1 because moving the executables broke them.

• Passing --cc=gcc-11 directly (viz. brew install isl --cc=gcc-11): Success. But then I'll have to keep this old version of gcc around, or symlink the newest gcc every time, because brew upgrade keeps previous install options.

• Passing --cc=gcc: Failure. Enigmatically, this doesn't require me to upgrade my gcc first. It still fails for compiler not supporting C++17's optionals (the same errors I pasted above), so it's probably not using Homebrew's gcc.

• Adding depends_on "gcc@11" => :build to isl.rb: Failure in all circumstances below for the same error. Apparently the gcc it found was still the alias to system clang

  • Upgrading directly
  • Setting CC=gcc in the interactive build environment
  • Passing --cc=gcc

• Adding depends_on "gcc" => :build instead: Failure. This time Homebrew wants to upgrade gcc first, which causes a circular dependency: ==> Installing dependencies for isl: gcc ==> Installing isl dependency: gcc ==> Installing dependencies for gcc: isl ==> Installing gcc dependency: isl ==> Installing dependencies for isl: gcc ==> Installing isl dependency: gcc (snip) ^C

  • Pulling out the old gcc.rb file matching my installed version, so that brew doesn't hit this circular dependency bug: Failure with the same C++17 unsupported error.

All in all, the simplest way to solve this - adding a dependency block - doesn't seem to work, nor does the un-versioned --cc=gcc option. I don't like the working way left, so I'm asking for help.

Section break

For all the unfortunate souls stuck on High Sierra, who don't have any version of Homebrew's gcc yet, so can't even get the first gcc installed, here's a solution - pull out an old version of isl's formula and install it first (I suppose you have dev tools already):

brew update         # Just to minimize the chance the formula gets updated in the mean time
cd "$(brew --repository homebrew/core)"
git checkout 912df90f851785d85995ea89db3ce125d7f4114e -- Formula/isl.rb         # This reverts to isl 0.24 which can be compiled with system clang
brew install isl
brew install gcc@11         # It's a long long build
git checkout master -- Formula/isl.rb         # Get the newest formula back
brew install isl --cc=gcc-11         # I hope some day we can pass --cc=gcc here, but not now
brew install gcc        # now you get the latest gcc

If still not work, you need to set the environment variable HOMEBREW_NO_INSTALL_FROM_API to 1 before any brew install command.