Don't always zero pad in print_*_chars

This changes print_octal_chars and print_decimal_chars to never zero
pad, and changes print_binary_chars and print_hex_chars to only
optionally zero-pad, based on a flag.

ChangeLog
2017-06-12  Tom Tromey  <tom@tromey.com>

	PR exp/16225:
	* valprint.h (print_binary_chars, print_hex_chars): Update.
	* valprint.c (val_print_type_code_int): Update.
	(print_binary_chars): Add "zero_pad" argument.
	(emit_octal_digit): New function.
	(print_octal_chars): Don't zero-pad.
	(print_decimal_chars): Likewise.
	(print_hex_chars): Add "zero_pad" argument.
	* sh64-tdep.c (sh64_do_fp_register): Update.
	* regcache.c (regcache::dump): Update.
	* printcmd.c (print_scalar_formatted): Update.
	* infcmd.c (default_print_one_register_info): Update.

2017-06-12  Tom Tromey  <tom@tromey.com>

	PR exp/16225:
	* gdb.reverse/i386-sse-reverse.exp: Update tests.
	* gdb.arch/vsx-regs.exp: Update tests.
	* gdb.arch/s390-vregs.exp (hex128): New proc.
	Update test.
	* gdb.arch/altivec-regs.exp: Update tests.

1 files changed, 92 insertions, 45 deletions

diff --git a/gdb/valprint.c b/gdb/valprint.c
index 6937dab..aa34b68 100644
--- a/gdb/valprint.c
+++ b/gdb/valprint.c
@@ -1264,7 +1264,7 @@ val_print_type_code_int (struct type *type, const gdb_byte *valaddr,
 	     complement (a reasonable assumption, I think) and do
 	     better than this.  */
 	  print_hex_chars (stream, (unsigned char *) valaddr,
-			   TYPE_LENGTH (type), byte_order);
+			   TYPE_LENGTH (type), byte_order, false);
 	}
     }
   else
@@ -1537,7 +1537,7 @@ print_decimal_floating (const gdb_byte *valaddr, struct type *type,
 
 void
 print_binary_chars (struct ui_file *stream, const gdb_byte *valaddr,
-		    unsigned len, enum bfd_endian byte_order)
+		    unsigned len, enum bfd_endian byte_order, bool zero_pad)
 {
 
 #define BITS_IN_BYTES 8
@@ -1545,14 +1545,13 @@ print_binary_chars (struct ui_file *stream, const gdb_byte *valaddr,
   const gdb_byte *p;
   unsigned int i;
   int b;
+  bool seen_a_one = false;
 
   /* Declared "int" so it will be signed.
      This ensures that right shift will shift in zeros.  */
 
   const int mask = 0x080;
 
-  /* FIXME: We should be not printing leading zeroes in most cases.  */
-
   if (byte_order == BFD_ENDIAN_BIG)
     {
       for (p = valaddr;
@@ -1565,11 +1564,14 @@ print_binary_chars (struct ui_file *stream, const gdb_byte *valaddr,
 	  for (i = 0; i < (BITS_IN_BYTES * sizeof (*p)); i++)
 	    {
 	      if (*p & (mask >> i))
-		b = 1;
+		b = '1';
 	      else
-		b = 0;
+		b = '0';
 
-	      fprintf_filtered (stream, "%1d", b);
+	      if (zero_pad || seen_a_one || b == '1')
+		fputc_filtered (b, stream);
+	      if (b == '1')
+		seen_a_one = true;
 	    }
 	}
     }
@@ -1582,14 +1584,34 @@ print_binary_chars (struct ui_file *stream, const gdb_byte *valaddr,
 	  for (i = 0; i < (BITS_IN_BYTES * sizeof (*p)); i++)
 	    {
 	      if (*p & (mask >> i))
-		b = 1;
+		b = '1';
 	      else
-		b = 0;
+		b = '0';
 
-	      fprintf_filtered (stream, "%1d", b);
+	      if (zero_pad || seen_a_one || b == '1')
+		fputc_filtered (b, stream);
+	      if (b == '1')
+		seen_a_one = true;
 	    }
 	}
     }
+
+  /* When not zero-padding, ensure that something is printed when the
+     input is 0.  */
+  if (!zero_pad && !seen_a_one)
+    fputc_filtered ('0', stream);
+}
+
+/* A helper for print_octal_chars that emits a single octal digit,
+   optionally suppressing it if is zero and updating SEEN_A_ONE.  */
+
+static void
+emit_octal_digit (struct ui_file *stream, bool *seen_a_one, int digit)
+{
+  if (*seen_a_one || digit != 0)
+    fprintf_filtered (stream, "%o", digit);
+  if (digit != 0)
+    *seen_a_one = true;
 }
 
 /* VALADDR points to an integer of LEN bytes.
@@ -1603,9 +1625,6 @@ print_octal_chars (struct ui_file *stream, const gdb_byte *valaddr,
   unsigned char octa1, octa2, octa3, carry;
   int cycle;
 
-  /* FIXME: We should be not printing leading zeroes in most cases.  */
-
-
   /* Octal is 3 bits, which doesn't fit.  Yuk.  So we have to track
    * the extra bits, which cycle every three bytes:
    *
@@ -1640,6 +1659,7 @@ print_octal_chars (struct ui_file *stream, const gdb_byte *valaddr,
   carry = 0;
 
   fputs_filtered ("0", stream);
+  bool seen_a_one = false;
   if (byte_order == BFD_ENDIAN_BIG)
     {
       for (p = valaddr;
@@ -1654,8 +1674,8 @@ print_octal_chars (struct ui_file *stream, const gdb_byte *valaddr,
 	      octa1 = (HIGH_ZERO & *p) >> 5;
 	      octa2 = (LOW_ZERO & *p) >> 2;
 	      carry = (CARRY_ZERO & *p);
-	      fprintf_filtered (stream, "%o", octa1);
-	      fprintf_filtered (stream, "%o", octa2);
+	      emit_octal_digit (stream, &seen_a_one, octa1);
+	      emit_octal_digit (stream, &seen_a_one, octa2);
 	      break;
 
 	    case 1:
@@ -1665,9 +1685,9 @@ print_octal_chars (struct ui_file *stream, const gdb_byte *valaddr,
 	      octa2 = (MID_ONE & *p) >> 4;
 	      octa3 = (LOW_ONE & *p) >> 1;
 	      carry = (CARRY_ONE & *p);
-	      fprintf_filtered (stream, "%o", octa1);
-	      fprintf_filtered (stream, "%o", octa2);
-	      fprintf_filtered (stream, "%o", octa3);
+	      emit_octal_digit (stream, &seen_a_one, octa1);
+	      emit_octal_digit (stream, &seen_a_one, octa2);
+	      emit_octal_digit (stream, &seen_a_one, octa3);
 	      break;
 
 	    case 2:
@@ -1677,9 +1697,9 @@ print_octal_chars (struct ui_file *stream, const gdb_byte *valaddr,
 	      octa2 = (MID_TWO & *p) >> 3;
 	      octa3 = (LOW_TWO & *p);
 	      carry = 0;
-	      fprintf_filtered (stream, "%o", octa1);
-	      fprintf_filtered (stream, "%o", octa2);
-	      fprintf_filtered (stream, "%o", octa3);
+	      emit_octal_digit (stream, &seen_a_one, octa1);
+	      emit_octal_digit (stream, &seen_a_one, octa2);
+	      emit_octal_digit (stream, &seen_a_one, octa3);
 	      break;
 
 	    default:
@@ -1704,8 +1724,8 @@ print_octal_chars (struct ui_file *stream, const gdb_byte *valaddr,
 	      octa1 = (HIGH_ZERO & *p) >> 5;
 	      octa2 = (LOW_ZERO & *p) >> 2;
 	      carry = (CARRY_ZERO & *p);
-	      fprintf_filtered (stream, "%o", octa1);
-	      fprintf_filtered (stream, "%o", octa2);
+	      emit_octal_digit (stream, &seen_a_one, octa1);
+	      emit_octal_digit (stream, &seen_a_one, octa2);
 	      break;
 
 	    case 1:
@@ -1715,9 +1735,9 @@ print_octal_chars (struct ui_file *stream, const gdb_byte *valaddr,
 	      octa2 = (MID_ONE & *p) >> 4;
 	      octa3 = (LOW_ONE & *p) >> 1;
 	      carry = (CARRY_ONE & *p);
-	      fprintf_filtered (stream, "%o", octa1);
-	      fprintf_filtered (stream, "%o", octa2);
-	      fprintf_filtered (stream, "%o", octa3);
+	      emit_octal_digit (stream, &seen_a_one, octa1);
+	      emit_octal_digit (stream, &seen_a_one, octa2);
+	      emit_octal_digit (stream, &seen_a_one, octa3);
 	      break;
 
 	    case 2:
@@ -1727,9 +1747,9 @@ print_octal_chars (struct ui_file *stream, const gdb_byte *valaddr,
 	      octa2 = (MID_TWO & *p) >> 3;
 	      octa3 = (LOW_TWO & *p);
 	      carry = 0;
-	      fprintf_filtered (stream, "%o", octa1);
-	      fprintf_filtered (stream, "%o", octa2);
-	      fprintf_filtered (stream, "%o", octa3);
+	      emit_octal_digit (stream, &seen_a_one, octa1);
+	      emit_octal_digit (stream, &seen_a_one, octa2);
+	      emit_octal_digit (stream, &seen_a_one, octa3);
 	      break;
 
 	    default:
@@ -1758,7 +1778,6 @@ print_decimal_chars (struct ui_file *stream, const gdb_byte *valaddr,
 #define HIGH_NIBBLE( x ) (((x) & 0x0F0) >> 4)
 
   const gdb_byte *p;
-  unsigned char *digits;
   int carry;
   int decimal_len;
   int i, j, decimal_digits;
@@ -1769,12 +1788,7 @@ print_decimal_chars (struct ui_file *stream, const gdb_byte *valaddr,
      as the base 16 number, which is 2 digits per byte.  */
 
   decimal_len = len * 2 * 2;
-  digits = (unsigned char *) xmalloc (decimal_len);
-
-  for (i = 0; i < decimal_len; i++)
-    {
-      digits[i] = 0;
-    }
+  std::vector<unsigned char> digits (decimal_len, 0);
 
   /* Ok, we have an unknown number of bytes of data to be printed in
    * decimal.
@@ -1868,40 +1882,73 @@ print_decimal_chars (struct ui_file *stream, const gdb_byte *valaddr,
   /* Ok, now "digits" is the decimal representation, with
      the "decimal_digits" actual digits.  Print!  */
 
-  for (i = decimal_digits - 1; i >= 0; i--)
+  for (i = decimal_digits - 1; i > 0 && digits[i] == 0; --i)
+    ;
+
+  for (; i >= 0; i--)
     {
       fprintf_filtered (stream, "%1d", digits[i]);
     }
-  xfree (digits);
 }
 
 /* VALADDR points to an integer of LEN bytes.  Print it in hex on stream.  */
 
 void
 print_hex_chars (struct ui_file *stream, const gdb_byte *valaddr,
-		 unsigned len, enum bfd_endian byte_order)
+		 unsigned len, enum bfd_endian byte_order,
+		 bool zero_pad)
 {
   const gdb_byte *p;
 
-  /* FIXME: We should be not printing leading zeroes in most cases.  */
-
   fputs_filtered ("0x", stream);
   if (byte_order == BFD_ENDIAN_BIG)
     {
-      for (p = valaddr;
+      p = valaddr;
+
+      if (!zero_pad)
+	{
+	  /* Strip leading 0 bytes, but be sure to leave at least a
+	     single byte at the end.  */
+	  for (; p < valaddr + len - 1 && !*p; ++p)
+	    ;
+	}
+
+      const gdb_byte *first = p;
+      for (;
 	   p < valaddr + len;
 	   p++)
 	{
-	  fprintf_filtered (stream, "%02x", *p);
+	  /* When not zero-padding, use a different format for the
+	     very first byte printed.  */
+	  if (!zero_pad && p == first)
+	    fprintf_filtered (stream, "%x", *p);
+	  else
+	    fprintf_filtered (stream, "%02x", *p);
 	}
     }
   else
     {
-      for (p = valaddr + len - 1;
+      p = valaddr + len - 1;
+
+      if (!zero_pad)
+	{
+	  /* Strip leading 0 bytes, but be sure to leave at least a
+	     single byte at the end.  */
+	  for (; p >= valaddr + 1 && !*p; --p)
+	    ;
+	}
+
+      const gdb_byte *first = p;
+      for (;
 	   p >= valaddr;
 	   p--)
 	{
-	  fprintf_filtered (stream, "%02x", *p);
+	  /* When not zero-padding, use a different format for the
+	     very first byte printed.  */
+	  if (!zero_pad && p == first)
+	    fprintf_filtered (stream, "%x", *p);
+	  else
+	    fprintf_filtered (stream, "%02x", *p);
 	}
     }
 }