Introduce a rake test:asan task for convenient running of Address Sanitizer (#141)

Rakefile

@@ -16,6 +16,21 @@ Rake::ExtensionTask.new( 'mini_racer_extension', gem )
 
 # via http://blog.flavorjon.es/2009/06/easily-valgrind-gdb-your-ruby-c.html
 namespace :test do
+  desc "run test suite with Address Sanitizer"
+  task :asan do
+    ENV["CONFIGURE_ARGS"] = [ENV["CONFIGURE_ARGS"], '--enable-asan'].compact.join(' ')
+    Rake::Task['compile'].invoke
+
+    asan_path = `ldconfig -N -p | grep libasan | sed 's/.* => \\(.*\\)$/\\1/'`.chomp
+
+    cmdline = "env LD_PRELOAD=\"#{asan_path}\" ruby test/test_leak.rb"
+    puts cmdline
+    system cmdline
+
+    cmdline = "env LD_PRELOAD=\"#{asan_path}\" rake test"
+    puts cmdline
+    system cmdline
+  end
   # partial-loads-ok and undef-value-errors necessary to ignore
   # spurious (and eminently ignorable) warnings from the ruby
   # interpreter

ext/mini_racer_extension/extconf.rb

@@ -49,10 +49,15 @@ if CONFIG['warnflags']
   CONFIG['warnflags'].gsub!('-Wimplicit-function-declaration', '')
 end
 
-if enable_config('debug')
+if enable_config('debug') || enable_config('asan')
   CONFIG['debugflags'] << ' -ggdb3 -O0'
 end
 
 Libv8.configure_makefile
 
+if enable_config('asan')
+  $CPPFLAGS.insert(0, " -fsanitize=address ")
+  $LDFLAGS.insert(0, " -fsanitize=address ")
+end
+
 create_makefile 'mini_racer_extension'