[RFC] Support for const char and strings in stabs reader

["Pierre Muller" <pierre.muller@ics-cnrs.unistra.fr>]

  Stabs reader currently only supports constants
of integer, real or enum types.

  This patch adds support for char and string types, as described in 
http://sourceware.org/gdb/current/onlinedocs/stabs/Constants.html#Constants

  I tried to implement support for both single and double
quote in the code.
 The string type is currently used for
Free Pascal compiler, so I could directly test it.

  I also tried to add some check to gdb.stabs testsuite,
but I got caught by some typical tcl expansion
problems while trying to test the second form
using double quotes...


The original lines in gdb.stabs/weird.def
# Test string constant
.stabs "constString1:c=s'String1'", N_LSYM,0,0, 0
.stabs "constString2:c=s\"String2\"", N_LSYM,0,0, 0
.stabs "constString3:c=s'String3 with embedded quote \' in the middle'",
N_LSYM,0,0, 0

become

.stabs "constString1:c=s'String1'", 0x80,0,0, 0
.stabs "constString2:c=s\\"String2\"", 0x80,0,0, 0
.stabs "constString3:c=s'String3 with embedded quote \\' in the middle'",
0x80,0,0, 0

Note the fact that only one of the two escaped double quote
is transformed into \\"..
I tried all combination, and nothing seemed to work...


Comments welcome,


Pierre Muller
Pascal language support maintainer for GDB

PS: I left the boolean support out
because currently objfile builtin_types
do not have a builtin_bool, which would be required
here.


2010-03-16  Pierre Muller  <muller@ics.u-strasbg.fr>

	* stabsread.c (define_symbol): Add support for char
	and string constants.

Index: stabsread.c
===================================================================
RCS file: /cvs/src/src/gdb/stabsread.c,v
retrieving revision 1.123
diff -u -p -r1.123 stabsread.c
--- stabsread.c	8 Jan 2010 08:55:16 -0000	1.123
+++ stabsread.c	16 Mar 2010 21:07:48 -0000
@@ -793,6 +793,56 @@ define_symbol (CORE_ADDR valu, char *str
 	    SYMBOL_CLASS (sym) = LOC_CONST;
 	  }
 	  break;
+
+	case 'c':
+	  {
+	    SYMBOL_TYPE (sym) = objfile_type (objfile)->builtin_char;
+	    SYMBOL_VALUE (sym) = atoi (p);
+	    SYMBOL_CLASS (sym) = LOC_CONST;
+	  }
+	  break;
+
+	case 's':
+	  {
+            struct type *range_type;
+	    char quote = *p++;
+            char *startp = p;
+            gdb_byte *string_value;
+            if (quote != '\'' && quote != '"')
+              {
+                SYMBOL_CLASS (sym) = LOC_CONST;
+                SYMBOL_TYPE (sym) = error_type (&p, objfile);
+                SYMBOL_DOMAIN (sym) = VAR_DOMAIN;
+                add_symbol_to_list (sym, &file_symbols);
+                return sym;
+              }
+            /* Find matching quote, rejecting escaped quotes.  */
+            while (*p && *p != quote)
+              {
+                if (*p == '\\')
+                  p++;
+                if (*p) 
+                  p++;
+              }
+            *p = '\0';
+            range_type = create_range_type (NULL,
+                           objfile_type (objfile)->builtin_int,
+                           0, strlen(startp));
+ 	    SYMBOL_TYPE (sym) = create_array_type (NULL,
+              objfile_type (objfile)->builtin_char,
+              range_type);
+	    string_value =
+	      obstack_alloc (&objfile->objfile_obstack,
+			     strlen (startp) + 1);
+	    strcpy ((char *)string_value, startp);
+            *p = quote;
+            p++;
+
+	    SYMBOL_VALUE_BYTES (sym) = string_value;
+	    SYMBOL_CLASS (sym) = LOC_CONST_BYTES;
+	  }
+	  break;
+
 	case 'e':
 	  /* SYMBOL:c=eTYPE,INTVALUE for a constant symbol whose value
 	     can be represented as integral.
Index: testsuite/gdb.stabs/weird.def
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.stabs/weird.def,v
retrieving revision 1.3
diff -u -p -r1.3 weird.def
--- testsuite/gdb.stabs/weird.def	8 Jan 2010 08:55:16 -0000	1.3
+++ testsuite/gdb.stabs/weird.def	16 Mar 2010 21:07:49 -0000
@@ -286,6 +286,15 @@ attr69:
 # Test constant with the type embedded.  
 .stabs "const70:c=e190=bs2;0;16;,70", N_LSYM,0,0, 0
 
+# Test char constant
+.stabs "constchar:c=70", N_LSYM,0,0, 0
+
+# Test string constant
+.stabs "constString1:c=s'String1'", N_LSYM,0,0, 0
+.stabs "constString2:c=s\"String2\"", N_LSYM,0,0, 0
+.stabs "constString3:c=s'String3 with embedded quote \' in the middle'",
N_LSYM,0,0, 0
+
+
 .stabs "attr38:G338=@&
!#$%&'()*+,-./0123456789:<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[]^_`abcdefghijklmno
pqrstuvwxyz{|}~;1",N_GSYM,0,0, 0
 
 # Unrecognized negative type number.  
Index: testsuite/gdb.stabs/weird.exp
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.stabs/weird.exp,v
retrieving revision 1.18
diff -u -p -r1.18 weird.exp
--- testsuite/gdb.stabs/weird.exp	1 Jan 2010 07:32:06 -0000	1.18
+++ testsuite/gdb.stabs/weird.exp	16 Mar 2010 21:07:49 -0000
@@ -164,6 +164,11 @@ proc do_tests {} {
 
 	gdb_test "p sizeof (const70)" " = 2" "'e' constant with embedded
type"
 
+	   gdb_test "p /x constchar" " = 0x46" "char constant"
+        gdb_test "p constString1" " = \"String1\"" "String constant 1"
+        gdb_test "p constString2" " = \"String2\"" "String constant 2"
+        gdb_test "p constString3" " = \"String3 with embedded quote ' in
the middle\"" "String constant 3"
+
 	gdb_test "p bad_neg0" " = \{field0 = 42, field2 =.*field3 = 45\}" "p
bad_neg0"
 
 	gdb_test "ptype inttype" "type = (unsigned int|inttype)" "ptype on
inttype"