Fix the RX assembler so that it can handle escaped double quote characters, ie: \"

PR 22737
	* config/tc-rx.c (rx_start_line): Handle escaped double-quote character.
	* testsuite/gas/rx/pr22737.s: New test.
	* testsuite/gas/rx/pr22737.d: Likewise.
	* testsuite/gas/rx/rx.exp: Run the new test.

gas/ChangeLog

@@ -1,3 +1,11 @@
+2018-01-22  Oleg Endo  <olegendo@gcc.gnu.org>
+
+	PR 22737
+	* config/tc-rx.c (rx_start_line): Handle escaped double-quote character.
+	* testsuite/gas/rx/pr22737.s: New test.
+	* testsuite/gas/rx/pr22737.d: Likewise.
+	* testsuite/gas/rx/rx.exp: Run the new test.
+
 2018-01-19  Thomas Preud'homme  <thomas.preudhomme@arm.com>
 
 	* config/tc-arm.c (ToC macro): Remove spurious comment.

gas/config/tc-rx.c

@@ -2681,6 +2681,7 @@ rx_start_line (void)
   int in_single_quote = 0;
   int done = 0;
   char * p = input_line_pointer;
+  char prev_char = 0;
 
   /* Scan the line looking for question marks.  Skip past quote enclosed regions.  */
   do
@@ -2693,7 +2694,9 @@ rx_start_line (void)
 	  break;
 
 	case '"':
-	  in_double_quote = ! in_double_quote;
+	  /* Handle escaped double quote \" inside a string.  */
+	  if (prev_char != '\\')
+	    in_double_quote = ! in_double_quote;
 	  break;
 
 	case '\'':
@@ -2722,7 +2725,7 @@ rx_start_line (void)
 	  break;
 	}
 
-      p ++;
+      prev_char = *p++;
     }
   while (! done);
 }

gas/testsuite/gas/rx/pr22737.d

@@ -0,0 +1,15 @@
+#objdump: -dr
+
+dump.o:     file format elf32-rx-le
+
+
+Disassembly of section .*:
+
+00000000 <.*>:
+   0:	ff 16.*
+   2:	c8 1f 68 22.*
+   6:	d0 64.*
+   8:	a0 3f.*
+   a:	3a e1 4f.*
+   d:	da 0e 8c b6 c6 9c.*
+.*

gas/testsuite/gas/rx/pr22737.s

@@ -0,0 +1 @@
+.ascii	"\377\026\310\037h\"\320d\240?:\341O\332\016\214\266\306\234."

gas/testsuite/gas/rx/rx.exp

@@ -35,3 +35,4 @@ foreach test [lsort [glob $srcdir/$subdir/*.sm]] {
 run_dump_test "rx-asm-good"
 # run_list_test "rx-asm-bad" "" "Generation of error messages with bogus Renesas assembler directives"
 run_dump_test "pr19665"
+run_dump_test "pr22737"