merge revision(s) 39958,39989: [Backport #8216]

	* lib/mkmf.rb (MAIN_DOES_NOTHING): force to refer symbols for tests
	  to be preserved.  [ruby-core:53745] [Bug #8169]

	* lib/mkmf.rb (MAIN_DOES_NOTHING): ensure symbols for tests to be
	  preserved.  [ruby-core:53745] [Bug #8169]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_3@40715 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 20 insertions, 7 deletions

diff --git a/lib/mkmf.rb b/lib/mkmf.rb
index a7517615ff..8f4e69e429 100644
--- a/lib/mkmf.rb
+++ b/lib/mkmf.rb
@@ -619,14 +619,14 @@ def try_func(func, libs, headers = nil, &b)
   try_link(<<"SRC", libs, &b) or
 #{headers}
 /*top*/
-#{MAIN_DOES_NOTHING}
 int t() { #{decltype["volatile p"]}; p = (#{decltype[]})#{func}; return 0; }
+#{MAIN_DOES_NOTHING "t"}
 SRC
   call && try_link(<<"SRC", libs, &b)
 #{headers}
 /*top*/
-#{MAIN_DOES_NOTHING}
 int t() { #{func}(); return 0; }
+#{MAIN_DOES_NOTHING "t"}
 SRC
 end
 
@@ -636,8 +636,8 @@ def try_var(var, headers = nil, &b)
   try_compile(<<"SRC", &b)
 #{headers}
 /*top*/
-#{MAIN_DOES_NOTHING}
 int t() { const volatile void *volatile p; p = &(&#{var})[0]; return 0; }
+#{MAIN_DOES_NOTHING "t"}
 SRC
 end
 
@@ -1002,8 +1002,8 @@ def have_struct_member(type, member, headers = nil, &b)
     if try_compile(<<"SRC", &b)
 #{cpp_include(headers)}
 /*top*/
-#{MAIN_DOES_NOTHING}
 int s = (char *)&((#{type}*)0)->#{member} - (char *)0;
+#{MAIN_DOES_NOTHING "s"}
 SRC
       $defs.push(format("-DHAVE_%s_%s", type.tr_cpp, member.tr_cpp))
       $defs.push(format("-DHAVE_ST_%s", member.tr_cpp)) # backward compatibility
@@ -1243,8 +1243,8 @@ def scalar_ptr_type?(type, member = nil, headers = nil, &b)
 #{cpp_include(headers)}
 /*top*/
 volatile #{type} conftestval;
-#{MAIN_DOES_NOTHING}
 int t() {return (int)(1-*(conftestval#{member ? ".#{member}" : ""}));}
+#{MAIN_DOES_NOTHING "t"}
 SRC
 end
 
@@ -1255,8 +1255,8 @@ def scalar_type?(type, member = nil, headers = nil, &b)
 #{cpp_include(headers)}
 /*top*/
 volatile #{type} conftestval;
-#{MAIN_DOES_NOTHING}
 int t() {return (int)(1-(conftestval#{member ? ".#{member}" : ""}));}
+#{MAIN_DOES_NOTHING "t"}
 SRC
 end
 
@@ -2226,6 +2226,19 @@ def mkmf_failed(path)
   end
 end
 
+def MAIN_DOES_NOTHING(*refs)
+  src = MAIN_DOES_NOTHING
+  unless refs.empty?
+    src = src.sub(/\{/) do
+      $& +
+        "\n  if (argc > 1000000) {\n" +
+        refs.map {|n|"    printf(\"%p\", &#{n});\n"}.join("") +
+        "  }\n"
+    end
+  end
+  src
+end
+
 # :startdoc:
 
 init_mkmf
@@ -2292,7 +2305,7 @@ LINK_SO = config_string('LINK_SO') ||
 LIBPATHFLAG = config_string('LIBPATHFLAG') || ' -L"%s"'
 RPATHFLAG = config_string('RPATHFLAG') || ''
 LIBARG = config_string('LIBARG') || '-l%s'
-MAIN_DOES_NOTHING = config_string('MAIN_DOES_NOTHING') || 'int main() {return 0;}'
+MAIN_DOES_NOTHING = config_string('MAIN_DOES_NOTHING') || "int main(int argc, char **argv)\n{\n  return 0;\n}"
 UNIVERSAL_INTS = config_string('UNIVERSAL_INTS') {|s| Shellwords.shellwords(s)} ||
   %w[int short long long\ long]