Fix undefined behavior in the Fortran, Go and Pascal number parsers

This commit ports these two fixes to the C parser:

  commit ebf13736b4
  CommitDate: Thu Sep 4 21:46:28 2014 +0100

      parse_number("0") reads uninitialized memory

  commit 20562150d8
  CommitDate: Wed Oct 3 15:19:06 2018 -0600

      Avoid undefined behavior in parse_number

... to the Fortran, Go, and Fortran number parsers, fixing the same
problems there.

Also add a new testcase that exercises printing 0xffffffffffffffff
(max 64-bit) in all languages, which crashes a GDB built with UBsan
without the fix.

I moved get_set_option_choices out of all-architectures.exp.tcl to
common code to be able to extract all the supported languages.  I did
a tweak to it to generalize it a bit -- you now have to pass down the
"set" part of the command as well.  This is so that the proc can be
used with "maintenance set" commands as well in future.

Change-Id: I8e8f2fdc1e8407f63d923c26fd55d98148b9e16a

gdb/f-exp.y

@@ -837,8 +837,8 @@ static int
 parse_number (struct parser_state *par_state,
 	      const char *p, int len, int parsed_float, YYSTYPE *putithere)
 {
-  LONGEST n = 0;
-  LONGEST prevn = 0;
+  ULONGEST n = 0;
+  ULONGEST prevn = 0;
   int c;
   int base = input_radix;
   int unsigned_p = 0;
@@ -869,7 +869,7 @@ parse_number (struct parser_state *par_state,
     }
 
   /* Handle base-switching prefixes 0x, 0t, 0d, 0 */
-  if (p[0] == '0')
+  if (p[0] == '0' && len > 1)
     switch (p[1])
       {
       case 'x':
@@ -929,7 +929,7 @@ parse_number (struct parser_state *par_state,
       /* If range checking enabled, portably test for unsigned overflow.  */
       if (RANGE_CHECK && n != 0)
 	{
-	  if ((unsigned_p && (unsigned)prevn >= (unsigned)n))
+	  if ((unsigned_p && prevn >= n))
 	    range_error (_("Overflow on numeric constant."));
 	}
       prevn = n;

gdb/go-exp.y

@@ -647,10 +647,8 @@ static int
 parse_number (struct parser_state *par_state,
 	      const char *p, int len, int parsed_float, YYSTYPE *putithere)
 {
-  /* FIXME: Shouldn't these be unsigned?  We don't deal with negative values
-     here, and we do kind of silly things like cast to unsigned.  */
-  LONGEST n = 0;
-  LONGEST prevn = 0;
+  ULONGEST n = 0;
+  ULONGEST prevn = 0;
   ULONGEST un;
 
   int i = 0;
@@ -702,7 +700,7 @@ parse_number (struct parser_state *par_state,
     }
 
   /* Handle base-switching prefixes 0x, 0t, 0d, 0.  */
-  if (p[0] == '0')
+  if (p[0] == '0' && len > 1)
     switch (p[1])
       {
       case 'x':
@@ -790,7 +788,7 @@ parse_number (struct parser_state *par_state,
 	 on 0x123456789 when LONGEST is 32 bits.  */
       if (c != 'l' && c != 'u' && n != 0)
 	{
-	  if ((unsigned_p && (ULONGEST) prevn >= (ULONGEST) n))
+	  if ((unsigned_p && prevn >= n))
 	    error (_("Numeric constant too large."));
 	}
       prevn = n;
@@ -808,7 +806,7 @@ parse_number (struct parser_state *par_state,
      the case where it is we just always shift the value more than
      once, with fewer bits each time.  */
 
-  un = (ULONGEST)n >> 2;
+  un = n >> 2;
   if (long_p == 0
       && (un >> (gdbarch_int_bit (par_state->gdbarch ()) - 2)) == 0)
     {

gdb/p-exp.y

@@ -803,10 +803,8 @@ static int
 parse_number (struct parser_state *par_state,
 	      const char *p, int len, int parsed_float, YYSTYPE *putithere)
 {
-  /* FIXME: Shouldn't these be unsigned?  We don't deal with negative values
-     here, and we do kind of silly things like cast to unsigned.  */
-  LONGEST n = 0;
-  LONGEST prevn = 0;
+  ULONGEST n = 0;
+  ULONGEST prevn = 0;
   ULONGEST un;
 
   int i = 0;
@@ -855,7 +853,7 @@ parse_number (struct parser_state *par_state,
     }
 
   /* Handle base-switching prefixes 0x, 0t, 0d, 0.  */
-  if (p[0] == '0')
+  if (p[0] == '0' && len > 1)
     switch (p[1])
       {
       case 'x':
@@ -933,7 +931,7 @@ parse_number (struct parser_state *par_state,
 	 on 0x123456789 when LONGEST is 32 bits.  */
       if (c != 'l' && c != 'u' && n != 0)
 	{
-	  if ((unsigned_p && (ULONGEST) prevn >= (ULONGEST) n))
+	  if (unsigned_p && prevn >= n)
 	    error (_("Numeric constant too large."));
 	}
       prevn = n;
@@ -951,7 +949,7 @@ parse_number (struct parser_state *par_state,
      the case where it is we just always shift the value more than
      once, with fewer bits each time.  */
 
-  un = (ULONGEST)n >> 2;
+  un = n >> 2;
   if (long_p == 0
       && (un >> (gdbarch_int_bit (par_state->gdbarch ()) - 2)) == 0)
     {

gdb/testsuite/gdb.base/all-architectures.exp.tcl

@@ -91,45 +91,25 @@ proc gdb_test_internal {cmd pattern {message ""}} {
 gdb_test_internal "set max-completions unlimited" \
     "^set max-completions unlimited"
 
-# Return a list of all the accepted values of "set WHAT".
-
-proc get_set_option_choices {what} {
-    global gdb_prompt
-
-    set values {}
-
-    set test "complete set $what"
-    gdb_test_multiple "complete set $what " "$test" {
-	-re "set $what (\[^\r\n\]+)\r\n" {
-	    lappend values $expect_out(1,string)
-	    exp_continue
-	}
-	-re "$gdb_prompt " {
-	    internal_pass $test
-	}
-    }
-    return $values
-}
-
-set supported_archs [get_set_option_choices "architecture"]
+set supported_archs [get_set_option_choices "set architecture"]
 # There should be at least one more than "auto".
 gdb_assert {[llength $supported_archs] > 1} "at least one architecture"
 
-set supported_osabis [get_set_option_choices "osabi"]
+set supported_osabis [get_set_option_choices "set osabi"]
 # There should be at least one more than "auto" and "default".
 gdb_assert {[llength $supported_osabis] > 2} "at least one osabi"
 
 if {[lsearch $supported_archs "mips"] >= 0} {
-    set supported_mipsfpu [get_set_option_choices "mipsfpu"]
-    set supported_mips_abi [get_set_option_choices "mips abi"]
+    set supported_mipsfpu [get_set_option_choices "set mipsfpu"]
+    set supported_mips_abi [get_set_option_choices "set mips abi"]
 
     gdb_assert {[llength $supported_mipsfpu] != 0} "at least one mipsfpu"
     gdb_assert {[llength $supported_mips_abi] != 0} "at least one mips abi"
 }
 
 if {[lsearch $supported_archs "arm"] >= 0} {
-    set supported_arm_fpu [get_set_option_choices "arm fpu"]
-    set supported_arm_abi [get_set_option_choices "arm abi"]
+    set supported_arm_fpu [get_set_option_choices "set arm fpu"]
+    set supported_arm_abi [get_set_option_choices "set arm abi"]
 
     gdb_assert {[llength $supported_arm_fpu] != 0} "at least one arm fpu"
     gdb_assert {[llength $supported_arm_abi] != 0} "at least one arm abi"

gdb/testsuite/gdb.base/parse_number.exp

@@ -0,0 +1,53 @@
+# Copyright 2022 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Test parsing numbers.  Several language parsers had the same bug
+# around parsing large 64-bit numbers, hitting undefined behavior, and
+# thus crashing a GDB built with UBSan.  This testcase goes over all
+# languages exercising printing the max 64-bit number, making sure
+# that GDB doesn't crash.
+
+proc test_parse_numbers {} {
+    clean_restart
+
+    set all_languages [get_set_option_choices "set language"]
+    foreach_with_prefix lang $all_languages {
+	gdb_test_no_output "set language $lang"
+
+	set val "0xffffffffffffffff"
+	if {$lang == "ada"} {
+	    gdb_test "p/x $val" "Integer literal out of range"
+	} elseif {$lang == "fortran"} {
+	    gdb_test "p/x $val" " = 0xffffffff"
+	    gdb_test "ptype $val" " = unsigned int"
+	} elseif {$lang == "modula-2"} {
+	    gdb_test "p/x 0FFFFFFFFFFFFFFFFH" "Overflow on numeric constant\\."
+	} elseif {$lang == "unknown"} {
+	    gdb_test "p/x $val" \
+		"expression parsing not implemented for language \"Unknown\""
+	} else {
+	    gdb_test "p/x $val" " = $val"
+	    if {$lang == "d"} {
+		gdb_test "ptype $val" " = ulong"
+	    } elseif {$lang == "rust"} {
+		gdb_test "ptype $val" " = i64"
+	    } else {
+		gdb_test "ptype $val" " = unsigned long long"
+	    }
+	}
+    }
+}
+
+test_parse_numbers

gdb/testsuite/lib/gdb.exp

@@ -8486,5 +8486,25 @@ gdb_caching_proc has_hw_wp_support {
     return $has_hw_wp_support
 }
 
+# Return a list of all the accepted values of the set command SET_CMD.
+
+proc get_set_option_choices {set_cmd} {
+    global gdb_prompt
+
+    set values {}
+
+    set test "complete $set_cmd"
+    gdb_test_multiple "complete $set_cmd " "$test" {
+	-re "$set_cmd (\[^\r\n\]+)\r\n" {
+	    lappend values $expect_out(1,string)
+	    exp_continue
+	}
+	-re "$gdb_prompt " {
+	    pass $test
+	}
+    }
+    return $values
+}
+
 # Always load compatibility stuff.
 load_lib future.exp