Merge pull request #5226 from shuujii/guess-toolchain-when-MRubyBuild-toolchain-argument-is-omitted

Guess toolchain when `MRuby::Build#toolchain` argument is omitted

build_config/default.rb

 MRuby::Build.new do |conf|
   # load specific toolchain settings
-
-  # Gets set by the VS command prompts.
-  if ENV['VisualStudioVersion'] || ENV['VSINSTALLDIR']
-    toolchain :visualcpp
-  else
-    toolchain :gcc
-  end
+  conf.toolchain
 
   # Use mrbgems
   # conf.gem 'examples/mrbgems/ruby_extension_example'

build_config/host-cxx.rb

 MRuby::Build.new do |conf|
-  toolchain :gcc
+  conf.toolchain
 
   # include the default GEMs
   conf.gembox 'default'

build_config/host-debug.rb

 MRuby::Build.new('host') do |conf|
   # load specific toolchain settings
-
-  # Gets set by the VS command prompts.
-  if ENV['VisualStudioVersion'] || ENV['VSINSTALLDIR']
-    toolchain :visualcpp
-  else
-    toolchain :gcc
-  end
+  conf.toolchain
 
   conf.enable_debug
 
@@ -20,7 +14,7 @@ MRuby::Build.new('host') do |conf|
   conf.gem :core => "mruby-bin-debugger"
 
   # test
-  enable_test
+  conf.enable_test
   # bintest
-  enable_bintest
+  conf.enable_bintest
 end

build_config/no-float.rb

 # Define cross build settings
 MRuby::CrossBuild.new('no-float') do |conf|
-  toolchain :gcc
+  conf.toolchain
 
   # include the GEM box
   conf.compilers.each do |c|

build_config/travis.rb

 MRuby::Build.new('full-debug') do |conf|
-  toolchain :gcc
+  conf.toolchain
   conf.enable_debug
 
   # include all core GEMs
@@ -10,7 +10,7 @@ MRuby::Build.new('full-debug') do |conf|
 end
 
 MRuby::Build.new do |conf|
-  toolchain :gcc
+  conf.toolchain
 
   # include all core GEMs
   conf.gembox 'full-core'
@@ -22,7 +22,7 @@ MRuby::Build.new do |conf|
 end
 
 MRuby::Build.new('cxx_abi') do |conf|
-  toolchain :gcc
+  conf.toolchain
 
   conf.gembox 'full-core'
   conf.cc.flags += %w(-fpermissive)
@@ -31,7 +31,7 @@ MRuby::Build.new('cxx_abi') do |conf|
   end
   conf.enable_test
 
-  enable_cxx_abi
+  conf.enable_cxx_abi
 
-  build_mrbc_exec
+  conf.build_mrbc_exec
 end

lib/mruby/build.rb

@@ -22,6 +22,18 @@ module MRuby
   class Toolchain
     class << self
       attr_accessor :toolchains
+
+      def guess
+        if cc = ENV["CC"] || ENV["CXX"]
+          return "clang" if cc.include?("clang")
+        else
+          return "clang" if RUBY_PLATFORM =~ /darwin|(?:free|open)bsd/
+          return "gcc" if RUBY_PLATFORM.include?("cygwin")
+          return "visualcpp" if ENV.include?("VisualStudioVersion")
+          return "visualcpp" if ENV.include?("VSINSTALLDIR")
+        end
+        "gcc"
+      end
     end
 
     def initialize(name, &block)
@@ -29,7 +41,7 @@ module MRuby
       MRuby::Toolchain.toolchains[@name] = self
     end
 
-    def setup(conf,params={})
+    def setup(conf, params={})
       conf.instance_exec(conf, params, &@initializer)
     end
 
@@ -221,7 +233,7 @@ EOS
       @enable_bintest
     end
 
-    def toolchain(name, params={})
+    def toolchain(name=Toolchain.guess, params={})
       name = name.to_s
       tc = Toolchain.toolchains[name] || begin
         path = "#{MRUBY_ROOT}/tasks/toolchains/#{name}.rake"