conformtest: Support testing macro usability in #if

["Joseph S. Myers" <joseph at codesourcery dot com>]

Many standard macros are specified to be integer constant expressions
usable in #if, so conformtest.pl should be able to test this property.
The best approach I have for testing usability in #if is to examine
the sign and each bit of the value one-by-one using #if, defining
macros based on the value of each bit and so eventually a macro with
the value the constant appears to have in #if, which can then be
compared with the value in normal C code.

I propose this patch which uses this approach to test this property.
Tested x86_64.

I think this is the last significant feature required to give
reasonable coverage to at least the header contents specified in ISO C
standards.

2012-04-28  Joseph Myers  <joseph@codesourcery.com>

	* conform/conformtest.pl: Handle "macro-int-constant" and test for
	usability of symbols in #if.

diff --git a/conform/conformtest.pl b/conform/conformtest.pl
index 2d8cfd7..4704deb 100644
--- a/conform/conformtest.pl
+++ b/conform/conformtest.pl
@@ -385,7 +385,7 @@ while ($#headers >= 0) {
 		     "Member \"$member\" does not have the correct type.",
 		     $res, 0);
       }
-    } elsif (/^(macro|constant|macro-constant) +([a-zA-Z0-9_]*) *(?:{([^}]*)} *)?(?:([>=<!]+) ([A-Za-z0-9_-]*))?/) {
+    } elsif (/^(macro|constant|macro-constant|macro-int-constant) +([a-zA-Z0-9_]*) *(?:{([^}]*)} *)?(?:([>=<!]+) ([A-Za-z0-9_-]*))?/) {
       my($symbol_type) = $1;
       my($symbol) = $2;
       my($type) = $3;
@@ -432,6 +432,43 @@ while ($#headers >= 0) {
 
       $res = $res || $mres || $cres;
 
+      if ($symbol_type eq "macro-int-constant" && ($res == 0 || !$optional)) {
+	# Test that the symbol is usable in #if.
+	open (TESTFILE, ">$fnamebase.c");
+	print TESTFILE "$prepend";
+	print TESTFILE "#include <$h>\n";
+	print TESTFILE "#if $symbol < 0\n";
+	print TESTFILE "# define conformtest_negative 1\n";
+	my($s) = "0";
+	for (my $i = 0; $i < 63; $i++) {
+	  print TESTFILE "# if $symbol & (1LL << $i)\n";
+	  print TESTFILE "#  define conformtest_bit_$i 0LL\n";
+	  print TESTFILE "# else\n";
+	  print TESTFILE "#  define conformtest_bit_$i (1LL << $i)\n";
+	  print TESTFILE "# endif\n";
+	  $s .= "|conformtest_bit_$i";
+	}
+	print TESTFILE "# define conformtest_value ~($s)\n";
+	print TESTFILE "#else\n";
+	print TESTFILE "# define conformtest_negative 0\n";
+	$s = "0";
+	for (my $i = 0; $i < 64; $i++) {
+	  print TESTFILE "# if $symbol & (1ULL << $i)\n";
+	  print TESTFILE "#  define conformtest_bit_$i (1ULL << $i)\n";
+	  print TESTFILE "# else\n";
+	  print TESTFILE "#  define conformtest_bit_$i 0ULL\n";
+	  print TESTFILE "# endif\n";
+	  $s .= "|conformtest_bit_$i";
+	}
+	print TESTFILE "# define conformtest_value ($s)\n";
+	print TESTFILE "#endif\n";
+	print TESTFILE "int main (void) { return !((($symbol < 0) == conformtest_negative) && ($symbol == conformtest_value)); }\n";
+	close (TESTFILE);
+
+	runtest ($fnamebase, "Testing for #if usability of symbol $symbol",
+		 "Symbol \"$symbol\" not usable in #if.", $res);
+      }
+
       if (defined ($type) && ($res == 0 || !$optional)) {
 	# Test the type of the symbol.
 	open (TESTFILE, ">$fnamebase.c");
@@ -744,7 +781,7 @@ while ($#headers >= 0) {
 
       if (/^element *({([^}]*)}|([^ ]*)) *({([^}]*)}|([^ ]*)) *([A-Za-z0-9_]*) *(.*)/) {
 	push @allow, $7;
-      } elsif (/^(macro|constant|macro-constant) +([a-zA-Z0-9_]*) *(?:{([^}]*)} *)?(?:([>=<!]+) ([A-Za-z0-9_-]*))?/) {
+      } elsif (/^(macro|constant|macro-constant|macro-int-constant) +([a-zA-Z0-9_]*) *(?:{([^}]*)} *)?(?:([>=<!]+) ([A-Za-z0-9_-]*))?/) {
 	push @allow, $1;
       } elsif (/^(type|tag) *({([^}]*)|([a-zA-Z0-9_]*))/) {
 	my($type) = "$3$4";

-- 
Joseph S. Myers
joseph@codesourcery.com