Improve handling of REPT pseudo op with a negative count.

PR 22324
	* read.c (s_rept): Use size_t type for count parameter.
	(do_repeat): Change type of count parameter to size_t.
	Issue an error is the count parameter is negative.
	(do_repeat_with_expression): Likewise.
	* read.h: Update prototypes for do_repeat and
	do_repeat_with_expression.
	* doc/as.texinfo (Rept): Document that a zero count is allowed but
	negative counts are not.
	* config/tc-rx.c (rx_rept): Use size_t type for count parameter.
	* config/tc-tic54x.c (tic54x_loop): Cast count parameter to size_t
	type.
	* testsuite/gas/macros/end.s: Add a test using a negative repeat
	count.
	* testsuite/gas/macros/end.l: Add expected error message.

gas/ChangeLog

@@ -1,3 +1,21 @@
+2017-10-20  Nick Clifton  <nickc@redhat.com>
+
+	PR 22324
+	* read.c (s_rept): Use size_t type for count parameter.
+	(do_repeat): Change type of count parameter to size_t.
+	Issue an error is the count parameter is negative.
+	(do_repeat_with_expression): Likewise.
+	* read.h: Update prototypes for do_repeat and
+	do_repeat_with_expression.
+	* doc/as.texinfo (Rept): Document that a zero count is allowed but
+	negative counts are not.
+	* config/tc-rx.c (rx_rept): Use size_t type for count parameter.
+	* config/tc-tic54x.c (tic54x_loop): Cast count parameter to size_t
+	type.
+	* testsuite/gas/macros/end.s: Add a test using a negative repeat
+	count.
+	* testsuite/gas/macros/end.l: Add expected error message.
+
 2017-10-19  Palmer Dabbelt  <palmer@dabbelt.com>
 
 	* config/tc-riscv.c (md_apply_fix): Mark

gas/config/tc-rx.c

@@ -560,7 +560,7 @@ rx_list (int ignore ATTRIBUTE_UNUSED)
 static void
 rx_rept (int ignore ATTRIBUTE_UNUSED)
 {
-  int count = get_absolute_expression ();
+  size_t count = get_absolute_expression ();
 
   do_repeat_with_expander (count, "MREPEAT", "ENDR", "..MACREP");
 }

gas/config/tc-tic54x.c

@@ -2031,7 +2031,7 @@ tic54x_loop (int count)
   if (!is_end_of_line[(int) *input_line_pointer])
     count = get_absolute_expression ();
 
-  do_repeat (count, "LOOP", "ENDLOOP");
+  do_repeat ((size_t) count, "LOOP", "ENDLOOP");
 }
 
 /* Normally, endloop gets eaten by the preceding loop.  */

gas/doc/as.texinfo

@@ -6392,6 +6392,9 @@ is equivalent to assembling
         .long   0
 @end example
 
+A count of zero is allowed, but nothing is generated.  Negative counts are not
+allowed and if encountered will be treated as if they were zero.
+
 @node Sbttl
 @section @code{.sbttl "@var{subheading}"}
 

gas/read.c

@@ -3106,9 +3106,9 @@ s_bad_end (int endr)
 void
 s_rept (int ignore ATTRIBUTE_UNUSED)
 {
-  int count;
+  size_t count;
 
-  count = get_absolute_expression ();
+  count = (size_t) get_absolute_expression ();
 
   do_repeat (count, "REPT", "ENDR");
 }
@@ -3117,11 +3117,17 @@ s_rept (int ignore ATTRIBUTE_UNUSED)
    different directives to be used as the start/end keys.  */
 
 void
-do_repeat (int count, const char *start, const char *end)
+do_repeat (size_t count, const char *start, const char *end)
 {
   sb one;
   sb many;
 
+  if (((ssize_t) count) < 0)
+    {
+      as_bad (_("negative count for %s - ignored"), start);
+      count = 0;
+    }
+
   sb_new (&one);
   if (!buffer_and_nest (start, end, &one, get_non_macro_line_sb))
     {
@@ -3144,7 +3150,7 @@ do_repeat (int count, const char *start, const char *end)
    block is replaced by the iteration count.  */
 
 void
-do_repeat_with_expander (int count,
+do_repeat_with_expander (size_t count,
 			 const char * start,
 			 const char * end,
 			 const char * expander)
@@ -3152,6 +3158,12 @@ do_repeat_with_expander (int count,
   sb one;
   sb many;
 
+  if (((ssize_t) count) < 0)
+    {
+      as_bad (_("negative count for %s - ignored"), start);
+      count = 0;
+    }
+
   sb_new (&one);
   if (!buffer_and_nest (start, end, &one, get_non_macro_line_sb))
     {
@@ -3172,7 +3184,7 @@ do_repeat_with_expander (int count,
 	  sb_build (& processed, one.len);
 	  sb_add_sb (& processed, & one);
 	  sub = strstr (processed.ptr, expander);
-	  len = sprintf (sub, "%d", count);
+	  len = sprintf (sub, "%lu", (unsigned long) count);
 	  gas_assert (len < 8);
 	  strcpy (sub + len, sub + 8);
 	  processed.len -= (8 - len);

gas/read.h

@@ -146,8 +146,8 @@ extern void stabs_generate_asm_file (void);
 extern void stabs_generate_asm_lineno (void);
 extern void stabs_generate_asm_func (const char *, const char *);
 extern void stabs_generate_asm_endfunc (const char *, const char *);
-extern void do_repeat (int,const char *,const char *);
-extern void do_repeat_with_expander (int, const char *, const char *, const char *);
+extern void do_repeat (size_t, const char *, const char *);
+extern void do_repeat_with_expander (size_t, const char *, const char *, const char *);
 extern void end_repeat (int);
 extern void do_parse_cons_expression (expressionS *, int);
 

gas/testsuite/gas/macros/end.l

@@ -1,3 +1,4 @@
 .*: Assembler messages:
 .*:1: Warning: \.endm .* \.macro
 .*:2: Warning: \.endr .* (\.rept|\.irpc?).*(\.rept|\.irpc?).*(\.rept|\.irpc?)
+.*:3: Error: negative count for REPT - ignored

gas/testsuite/gas/macros/end.s

@@ -1,2 +1,5 @@
 	.endm
 	.endr
+	.rept -1
+	.endr
+