Re: [PATCH] Fix ptype problem printing typedefs defined differently in different compilation units

[Fred Fish <fnf@specifix.com>]

On Saturday 11 February 2006 15:20, Daniel Jacobowitz wrote:
> Well, if the results of ptype_eval and evaluate_type are inconsistent
> here, won't the result of doing this be meaningless?  And if they were
> already consistent, then I'm a little confused how your patch works.

ptype_eval extracted the type directly from the expression, while
evaluate_type creates a value, which it wasn't prepared to do from
just a typedef name.

In any case, I think I found a better solution, which is basically to
eliminate ptype_eval and let the expression evaluator create a value
with the right type.  The actual value isn't important, since we're
only going to use it's type.  This is how the ADA expression evaluator
handles evaluating an OP_TYPE expression.

> > > Also ptype will now do the RTTI lookup; I'm not sure whether it
> > > should or not.
> > 
> > Not sure either, now that you point it out.
> 
> Might as well let it.

OK, then we can let whatis_exp handle both ptype and whatis.

Attached is a reworked patch, with a couple of additional testsuite
changes.

-Fred

Gdb ChangeLog entry:

	2006-02-12  Fred Fish  <fnf@specifix.com>

	* eval.c (evaluate_subexp_standard): For OP_VAR_VALUE, if exp
	is a typedef, return a non lval value zero, of the appropriate
	type, when avoiding side effects.
	For OP_TYPE, return a non lval value zero, of the appropriate
	type, when avoiding side effects.
	* typeprint.c (ptype_eval): Remove function and declaration.
	(ptype_command): Simplify to just a call to whatis_exp.
 	

Testsuite ChangeLog entry:

	2006-02-12  Fred Fish  <fnf@specifix.com>

	* gdb.base/ptype.c: Add afoo for typedef checks.
	* gdb.base/ptype1.c: Add afoo for typedef checks.
	* gdb.base/whatis.c: Add typedef foo and var afoo.

	* gdb.base/ptype.exp: Add tests for 'file'::symbol and
	'file'::typename syntax.  Add tests using value history.
	* gdb.base/whatis.exp: Ditto.

Index: eval.c
===================================================================
RCS file: /cvsroots/latest/src/gdb/gdb/eval.c,v
retrieving revision 1.1.1.2
diff -c -p -r1.1.1.2 eval.c
*** eval.c	30 Dec 2005 18:53:04 -0000	1.1.1.2
--- eval.c	12 Feb 2006 18:07:29 -0000
*************** evaluate_subexp_standard (struct type *e
*** 461,466 ****
--- 461,472 ----
  	 value_rtti_target_type () if we are dealing with a pointer
  	 or reference to a base class and print object is on. */
  
+       /* If asked to evaluate a typedef, and we are avoiding side effects,
+ 	 then create a value of the appropriate type to return. */
+       if (noside == EVAL_AVOID_SIDE_EFFECTS
+ 	  && SYMBOL_CLASS (exp->elts[pc + 2].symbol) == LOC_TYPEDEF)
+ 	return (allocate_value (SYMBOL_TYPE (exp->elts[2].symbol)));
+       else
  	return value_of_variable (exp->elts[pc + 2].symbol,
  				  exp->elts[pc + 1].block);
  
*************** evaluate_subexp_standard (struct type *e
*** 2086,2092 ****
        return value_of_local ("self", 1);
  
      case OP_TYPE:
!       error (_("Attempt to use a type name as an expression"));
  
      default:
        /* Removing this case and compiling with gcc -Wall reveals that
--- 2092,2106 ----
        return value_of_local ("self", 1);
  
      case OP_TYPE:
!       /* The value is not supposed to be used.  This is here to make it
!          easier to accommodate expressions that contain types.  */
!       (*pos) += 2;
!       if (noside == EVAL_SKIP)
!         goto nosideret;
!       else if (noside == EVAL_AVOID_SIDE_EFFECTS)
!         return allocate_value (exp->elts[pc + 1].type);
!       else
!         error (_("Attempt to use a type name as an expression"));
  
      default:
        /* Removing this case and compiling with gcc -Wall reveals that
Index: typeprint.c
===================================================================
RCS file: /cvsroots/latest/src/gdb/gdb/typeprint.c,v
retrieving revision 1.1.1.2
diff -c -p -r1.1.1.2 typeprint.c
*** typeprint.c	30 Dec 2005 18:53:06 -0000	1.1.1.2
--- typeprint.c	12 Feb 2006 18:07:29 -0000
*************** extern void _initialize_typeprint (void)
*** 45,52 ****
  
  static void ptype_command (char *, int);
  
- static struct type *ptype_eval (struct expression *);
- 
  static void whatis_command (char *, int);
  
  static void whatis_exp (char *, int);
--- 45,50 ----
*************** whatis_command (char *exp, int from_tty)
*** 182,236 ****
    whatis_exp (exp, -1);
  }
  
- /* Simple subroutine for ptype_command.  */
- 
- static struct type *
- ptype_eval (struct expression *exp)
- {
-   if (exp->elts[0].opcode == OP_TYPE)
-     {
-       return (exp->elts[1].type);
-     }
-   else
-     {
-       return (NULL);
-     }
- }
- 
  /* TYPENAME is either the name of a type, or an expression.  */
  
  static void
  ptype_command (char *typename, int from_tty)
  {
!   struct type *type;
!   struct expression *expr;
!   struct cleanup *old_chain;
! 
!   if (typename == NULL)
!     {
!       /* Print type of last thing in value history. */
!       whatis_exp (typename, 1);
!     }
!   else
!     {
!       expr = parse_expression (typename);
!       old_chain = make_cleanup (free_current_contents, &expr);
!       type = ptype_eval (expr);
!       if (type != NULL)
! 	{
! 	  /* User did "ptype <typename>" */
! 	  printf_filtered ("type = ");
! 	  type_print (type, "", gdb_stdout, 1);
! 	  printf_filtered ("\n");
! 	  do_cleanups (old_chain);
! 	}
!       else
! 	{
! 	  /* User did "ptype <symbolname>" */
! 	  do_cleanups (old_chain);
! 	  whatis_exp (typename, 1);
! 	}
!     }
  }
  
  /* Print integral scalar data VAL, of type TYPE, onto stdio stream STREAM.
--- 180,191 ----
    whatis_exp (exp, -1);
  }
  
  /* TYPENAME is either the name of a type, or an expression.  */
  
  static void
  ptype_command (char *typename, int from_tty)
  {
!   whatis_exp (typename, 1);
  }
  
  /* Print integral scalar data VAL, of type TYPE, onto stdio stream STREAM.
Index: testsuite/gdb.base/ptype.c
===================================================================
RCS file: /cvsroots/latest/src/gdb/gdb/testsuite/gdb.base/ptype.c,v
retrieving revision 1.1.1.2
diff -c -p -r1.1.1.2 ptype.c
*** testsuite/gdb.base/ptype.c	8 Jan 2006 20:37:18 -0000	1.1.1.2
--- testsuite/gdb.base/ptype.c	10 Feb 2006 21:38:14 -0000
*************** func_type v_func_type;
*** 260,265 ****
--- 260,266 ----
  /***********/
  
  typedef int foo;
+ static foo afoo = 2;
  
  foo intfoo (afoo)
  {
Index: testsuite/gdb.base/ptype.exp
===================================================================
RCS file: /cvsroots/latest/src/gdb/gdb/testsuite/gdb.base/ptype.exp,v
retrieving revision 1.1.1.2
diff -c -p -r1.1.1.2 ptype.exp
*** testsuite/gdb.base/ptype.exp	8 Jan 2006 20:37:19 -0000	1.1.1.2
--- testsuite/gdb.base/ptype.exp	12 Feb 2006 12:54:42 -0000
*************** gdb_test "list intfoo" ""
*** 593,598 ****
--- 593,610 ----
  gdb_test "ptype foo" "type = int" "ptype foo typedef after second list of intfoo"
  gdb_test "list charfoo" ""
  gdb_test "ptype foo" "type = char" "ptype foo typedef after second list of charfoo"
+ # Test the 'file'::exp syntax for variables and types
+ gdb_test "ptype 'ptype.c'::afoo" "type = int" "ptype 'file'::symbol"
+ gdb_test "ptype 'ptype.c'::foo" "type = int" "ptype 'file'::typename"
+ gdb_test "ptype 'ptype1.c'::afoo" "type = char" "ptype 'file'::symbol"
+ gdb_test "ptype 'ptype1.c'::foo" "type = char" "ptype 'file'::typename"
+ 
+ # Test printing value history type
+ 
+ gdb_test "p (long)1" ""
+ gdb_test "ptype" "type = long" "ptype long value from value history"
+ gdb_test "p (short)1" ""
+ gdb_test "ptype" "type = short" "ptype short value from value history"
  
  # Test printing type of string constants and array constants, but
  # requires a running process.  These call malloc, and can take a long
Index: testsuite/gdb.base/ptype1.c
===================================================================
RCS file: /cvsroots/latest/src/gdb/gdb/testsuite/gdb.base/ptype1.c,v
retrieving revision 1.1.1.1
diff -c -p -r1.1.1.1 ptype1.c
*** testsuite/gdb.base/ptype1.c	8 Jan 2006 20:37:18 -0000	1.1.1.1
--- testsuite/gdb.base/ptype1.c	10 Feb 2006 21:37:55 -0000
***************
*** 1,4 ****
--- 1,5 ----
  typedef char foo;
+ static foo afoo = 1;
  
  foo charfoo (afoo)
  {
Index: testsuite/gdb.base/whatis.c
===================================================================
RCS file: /cvsroots/latest/src/gdb/gdb/testsuite/gdb.base/whatis.c,v
retrieving revision 1.1.1.1
diff -c -p -r1.1.1.1 whatis.c
*** testsuite/gdb.base/whatis.c	8 Oct 2005 19:36:19 -0000	1.1.1.1
--- testsuite/gdb.base/whatis.c	10 Feb 2006 21:35:00 -0000
*************** unsigned long	v_unsigned_long;
*** 46,51 ****
--- 46,54 ----
  float		v_float;
  double		v_double;
  
+ typedef int foo;
+ static foo afoo = 1;
+ 
  /*
   *	Now some derived types, which are arrays, functions-returning,
   *	pointers, structures, unions, and enumerations.
Index: testsuite/gdb.base/whatis.exp
===================================================================
RCS file: /cvsroots/latest/src/gdb/gdb/testsuite/gdb.base/whatis.exp,v
retrieving revision 1.1.1.1
diff -c -p -r1.1.1.1 whatis.exp
*** testsuite/gdb.base/whatis.exp	8 Oct 2005 19:36:19 -0000	1.1.1.1
--- testsuite/gdb.base/whatis.exp	12 Feb 2006 12:55:26 -0000
*************** gdb_test "whatis nested_su.inner_union_i
*** 402,404 ****
--- 402,421 ----
  gdb_test "whatis nested_su.inner_union_instance.inner_union_int" \
      "type = int" \
      "whatis inner union member"
+ 
+ # Test the 'file'::exp syntax for variables and types
+ 
+ gdb_test "whatis 'whatis.c'::afoo" \
+     "type = foo" \
+     "whatis 'file'::symbol"
+ 
+ gdb_test "whatis 'whatis.c'::foo" \
+     "type = int" \
+     "whatis 'file'::typename"
+ 
+ # Test printing value history type
+ 
+ gdb_test "p (long)1" ""
+ gdb_test "whatis" "type = long" "whatis long value from value history"
+ gdb_test "p (short)1" ""
+ gdb_test "whatis" "type = short" "whatis short value from value history"