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* Re: [rfa/c++] cp_lookup_rtti_type, take 2
@ 2003-12-05  5:26 Michael Elizabeth Chastain
  0 siblings, 0 replies; 11+ messages in thread
From: Michael Elizabeth Chastain @ 2003-12-05  5:26 UTC (permalink / raw)
  To: drow, mec.gnu; +Cc: carlton, gdb-patches

mec> Maybe we should just go from the vtbl address to the symbol without
mec> converting to a name and back again?!

drow> We don't have any information to do that, unless you know something I
drow> don't.

No, I know much less than you about symtabs.  Rats.  :(

drow> You may have to start bootstrap a little further back than usual. 
drow> You'll need at least GNU Make... HP-UX's make is incredibly annoying.

Migchain starts with gnu make, which bootstraps with no "make" at all
(just a shell script with two dozen "cc ..." lines in it.  You probably
knew that).  I brought it up on an impovershed solaris machine about a
year ago.  So I'm ready for this part.

But now I gotta get back to all those other little pieces of work
I said I would do after this patch went in.

Michael C


^ permalink raw reply	[flat|nested] 11+ messages in thread
* Re: [rfa/c++] cp_lookup_rtti_type, take 2
@ 2003-12-05  4:23 Michael Elizabeth Chastain
  2003-12-05  5:01 ` Daniel Jacobowitz
  2003-12-05 17:12 ` David Carlton
  0 siblings, 2 replies; 11+ messages in thread
From: Michael Elizabeth Chastain @ 2003-12-05  4:23 UTC (permalink / raw)
  To: drow, mec.gnu; +Cc: carlton, gdb-patches

Cool, I will commit this patch now.

> The only reason we can do it by symbol lookup at all is the One
> Definition Rule, and we should probably be restricting ourselves to the
> objfile in which we found the minimal symbol.

Yes, it's still very flaky.  The only reason it works now is that
there is a low-priority "fallback" search over all static blocks.
That is just more trouble waiting to happen.

We've got a vtbl pointer, and we want type information for it.
So we translate:

  vtbl address -> minsym
  minsym -> mangled name
  mangled name -> demangled name
  demangled name -> prefix
  prefix -> symbol
  symbol -> type

Maybe we should just go from the vtbl address to the symbol without
converting to a name and back again?!

> Now that we've had another major release of GDB I am extremely tempted
> to rip out aCC C++ support.  If you really want to experiment, the HP
> TestDrive systems do have aCC installed; www.testdrive.hp.com and
> spe191.testdrive.hp.com:telnet.  But they're a real nuisance to run
> tests on due to the lack of usable (to me) tools, and the restrictive
> firewall.

That's in my area.  "Get into testdrive" is a task for me, and "set up
migchain/migbat" is another task.  I can handle the lack of tools as
long as there is lots of disk space, because I bootstrap the whole
toolchain.  I'll have to see how restrictive the firewall is.

> And if we found problems, there wouldn't be anyone motivated
> to fix them.

Well, it would be useful to get enough hpux running to clean up
all the hp/acc special code in the test suite.  It would be great
if acc is completely getting replaced, too.

> The "earlier version" used VAR_DOMAIN, FYI.  It was presumably based on
> the code in gnu-v2-abi.c, but because gnu-v2-abi.c didn't show the
> problem I encountered at the time I didn't update it.

Aha, the history is falling into place.

In retrospect, my new lookup_rtti_type should take the domain as a parameter.

This is the major regression from gdb 6.0 to gdb HEAD.  I'd like to get
gdb HEAD to a state where there are no known regressions.  I have a
goal that gdb_6_1-branch will take only 6 weeks from cutting the branch
to the release!

Michael C


^ permalink raw reply	[flat|nested] 11+ messages in thread
* [rfa/c++] cp_lookup_rtti_type, take 2
@ 2003-12-01 21:40 Michael Elizabeth Chastain
  2003-12-05  3:30 ` Daniel Jacobowitz
  0 siblings, 1 reply; 11+ messages in thread
From: Michael Elizabeth Chastain @ 2003-12-01 21:40 UTC (permalink / raw)
  To: dan, gdb-patches; +Cc: carlton

Here is version #2 of cp_lookup_rtti_type.

Changes since version #1:

  . changed name from lookup_rtti_type to cp_lookup_rtti_type.
  . cp_lookup_rtti_type lives in cp-support.h/cp-support.c
      instead of symtab.h/gdbtypes.c.
  . tweaked one of the warning messages
    . old: "RTTI symbol for class '%s' is not a typedef"
    . new: "RTTI symbol for class '%s' is not a type"

It's still the same basic plan where cp_lookup_rtti_type is a chunk
of code that used to be in gnuv3_rtti_type, with more sanity checking,
and now gnuv2_rtti_type uses it too, so now gnuv2_rtti_type works.

And it still needs this follow-up work:

. The calls to lookup_rtti_type need a proper "block" parameter.
  The old code needed this too; I haven't regressed anything.
  I put FIXME notes in for this.

. hpacc_value_rtti_type has the same buggy code.  I can't change the
  code because I can't test it, but I can put in a big FIXME into it.
  (I wonder if anyone still uses HP aCC with gdb).

. Nested types give a warning and don't work.
  It would be nice to make them work.

. Types with virtual bases appear to work with v3, but give a warning
  and don't work with v2.  "don't work" probably means that they fall back
  to the static type rather than the dynamic type, which probably
  usually works.  Again, this is also a property of the current code.

. rtti.exp needs to recognize a modified message (see below).

The PR's are:

  http://sources.redhat.com/gdb/bugs/1465
  http://sources.redhat.com/gdb/bugs/1377

These bugs are regressions versus gdb 6.0 so they are high priority.

Testing: I tested with gcc v2 and v3, dwarf-2 and stabs+.   
Nothing got worse.  gdb.cp/class2.exp has a specific test for this,
which now passes.  Some tests in gdb.cp/rtti.exp changed their
kfail number so rtti.exp will need an upgrade.

Some tests in virtfunc.exp that broke after the 2003-09-11 namespace
commit started working again:

  http://sources.redhat.com/gdb/bugs/1377
  [regression] g++ 2.95.3, dwarf-2, hand function call: SIGSEGV</tt>

Since I'm not in symtab.h/gdbtypes.c any more, I don't think I need
approval from a symtab maintainer, just a C++ maintainer.  Lart me if
I'm wrong.

Okay to commit?

Michael C

2003-12-01  Michael Chastain  <mec.gnu@mindspring.com>

	Partial fix for PR c++/1465.
	Fix for PR c++/1377.
	* cp-support.h (cp_lookup_rtti_type): New function.
	* cp-support.c (cp_lookup_rtti_type): New function.
	* gnu-v2-abi.c: Update copyright years.
	(gnuv2_rtti_type): Call cp_lookup_rtti_type.
	* gnu-v3-abi.c: Update copyright years.
	(gnuv3_rtti_type): Call cp_lookup_rtti_type.

Index: cp-support.h
===================================================================
RCS file: /cvs/src/src/gdb/cp-support.h,v
retrieving revision 1.9
diff -c -3 -p -r1.9 cp-support.h
*** cp-support.h	25 Sep 2003 16:39:38 -0000	1.9
--- cp-support.h	1 Dec 2003 20:03:35 -0000
*************** struct symbol;
*** 34,39 ****
--- 34,40 ----
  struct obstack;
  struct block;
  struct objfile;
+ struct type;
  
  /* This struct is designed to store data from using directives.  It
     says that names from namespace INNER should be visible within
*************** extern unsigned int cp_find_first_compon
*** 60,65 ****
--- 61,69 ----
  extern unsigned int cp_entire_prefix_len (const char *name);
  
  extern struct symbol **make_symbol_overload_list (struct symbol *);
+ 
+ extern struct type *cp_lookup_rtti_type (const char *name,
+ 					 struct block *block);
  
  /* Functions/variables from cp-namespace.c.  */
  
Index: cp-support.c
===================================================================
RCS file: /cvs/src/src/gdb/cp-support.c,v
retrieving revision 1.9
diff -c -3 -p -r1.9 cp-support.c
*** cp-support.c	14 Sep 2003 16:32:12 -0000	1.9
--- cp-support.c	1 Dec 2003 20:03:36 -0000
***************
*** 33,38 ****
--- 33,39 ----
  #include "symtab.h"
  #include "block.h"
  #include "complaints.h"
+ #include "gdbtypes.h"
  
  /* Functions related to demangled name parsing.  */
  
*************** make_symbol_overload_list (struct symbol
*** 582,587 ****
--- 583,630 ----
    return (sym_return_val);
  }
  
+ /* Lookup the rtti type for a class name. */
+ 
+ struct type *
+ cp_lookup_rtti_type (const char *name, struct block *block)
+ {
+   struct symbol * rtti_sym;
+   struct type * rtti_type;
+ 
+   rtti_sym = lookup_symbol (name, block, STRUCT_DOMAIN, NULL, NULL);
+ 
+   if (rtti_sym == NULL)
+     {
+       warning ("RTTI symbol not found for class '%s'", name);
+       return NULL;
+     }
+ 
+   if (SYMBOL_CLASS (rtti_sym) != LOC_TYPEDEF)
+     {
+       warning ("RTTI symbol for class '%s' is not a type", name);
+       return NULL;
+     }
+ 
+   rtti_type = SYMBOL_TYPE (rtti_sym);
+ 
+   switch (TYPE_CODE (rtti_type))
+     {
+     case TYPE_CODE_CLASS:
+       break;
+     case TYPE_CODE_NAMESPACE:
+       /* chastain/2003-11-26: the symbol tables often contain fake
+ 	 symbols for namespaces with the same name as the struct.
+ 	 This warning is an indication of a bug in the lookup order
+ 	 or a bug in the way that the symbol tables are populated.  */
+       warning ("RTTI symbol for class '%s' is a namespace", name);
+       return NULL;
+     default:
+       warning ("RTTI symbol for class '%s' has bad type", name);
+       return NULL;
+     }
+ 
+   return rtti_type;
+ }
  
  /* Don't allow just "maintenance cplus".  */
  
Index: gnu-v2-abi.c
===================================================================
RCS file: /cvs/src/src/gdb/gnu-v2-abi.c,v
retrieving revision 1.13
diff -c -3 -p -r1.13 gnu-v2-abi.c
*** gnu-v2-abi.c	16 Sep 2003 18:56:35 -0000	1.13
--- gnu-v2-abi.c	1 Dec 2003 20:03:37 -0000
***************
*** 1,6 ****
  /* Abstraction of GNU v2 abi.
  
!    Copyright 2001, 2003 Free Software Foundation, Inc.
  
     Contributed by Daniel Berlin <dberlin@redhat.com>
  
--- 1,6 ----
  /* Abstraction of GNU v2 abi.
  
!    Copyright 2001, 2002, 2003 Free Software Foundation, Inc.
  
     Contributed by Daniel Berlin <dberlin@redhat.com>
  
***************
*** 30,35 ****
--- 30,36 ----
  #include "value.h"
  #include "demangle.h"
  #include "cp-abi.h"
+ #include "cp-support.h"
  
  #include <ctype.h>
  
*************** gnuv2_value_rtti_type (struct value *v, 
*** 259,267 ****
    *(strchr(demangled_name,' '))=0;
  
    /* Lookup the type for the name */
!   rtti_type=lookup_typename(demangled_name, (struct block *)0,1);
! 
!   if (rtti_type==NULL)
      return NULL;
  
    if (TYPE_N_BASECLASSES(rtti_type) > 1 &&  full && (*full) != 1)
--- 260,268 ----
    *(strchr(demangled_name,' '))=0;
  
    /* Lookup the type for the name */
!   /* FIXME: chastain/2003-11-26: block=NULL is bogus.  See pr gdb/1465. */
!   rtti_type = cp_lookup_rtti_type (demangled_name, NULL);
!   if (rtti_type == NULL)
      return NULL;
  
    if (TYPE_N_BASECLASSES(rtti_type) > 1 &&  full && (*full) != 1)
Index: gnu-v3-abi.c
===================================================================
RCS file: /cvs/src/src/gdb/gnu-v3-abi.c,v
retrieving revision 1.19
diff -c -3 -p -r1.19 gnu-v3-abi.c
*** gnu-v3-abi.c	22 Aug 2003 20:45:55 -0000	1.19
--- gnu-v3-abi.c	1 Dec 2003 20:03:37 -0000
***************
*** 1,7 ****
  /* Abstraction of GNU v3 abi.
     Contributed by Jim Blandy <jimb@redhat.com>
  
!    Copyright 2001, 2002 Free Software Foundation, Inc.
  
     This file is part of GDB.
  
--- 1,7 ----
  /* Abstraction of GNU v3 abi.
     Contributed by Jim Blandy <jimb@redhat.com>
  
!    Copyright 2001, 2002, 2003 Free Software Foundation, Inc.
  
     This file is part of GDB.
  
***************
*** 23,28 ****
--- 23,29 ----
  #include "defs.h"
  #include "value.h"
  #include "cp-abi.h"
+ #include "cp-support.h"
  #include "demangle.h"
  #include "gdb_assert.h"
  #include "gdb_string.h"
*************** gnuv3_rtti_type (struct value *value,
*** 196,202 ****
    struct minimal_symbol *vtable_symbol;
    const char *vtable_symbol_name;
    const char *class_name;
-   struct symbol *class_symbol;
    struct type *run_time_type;
    struct type *base_type;
    LONGEST offset_to_top;
--- 197,202 ----
*************** gnuv3_rtti_type (struct value *value,
*** 255,280 ****
    class_name = vtable_symbol_name + 11;
  
    /* Try to look up the class name as a type name.  */
!   class_symbol = lookup_symbol (class_name, 0, STRUCT_DOMAIN, 0, 0);
!   if (! class_symbol)
!     {
!       warning ("can't find class named `%s', as given by C++ RTTI", class_name);
!       return NULL;
!     }
! 
!   /* Make sure the type symbol is sane.  (An earlier version of this
!      code would find constructor functions, who have the same name as
!      the class.)  */
!   if (SYMBOL_CLASS (class_symbol) != LOC_TYPEDEF
!       || TYPE_CODE (SYMBOL_TYPE (class_symbol)) != TYPE_CODE_CLASS)
!     {
!       warning ("C++ RTTI gives a class name of `%s', but that isn't a type name",
! 	       class_name);
!       return NULL;
!     }
! 
!   /* This is the object's run-time type!  */
!   run_time_type = SYMBOL_TYPE (class_symbol);
  
    /* Get the offset from VALUE to the top of the complete object.
       NOTE: this is the reverse of the meaning of *TOP_P.  */
--- 255,264 ----
    class_name = vtable_symbol_name + 11;
  
    /* Try to look up the class name as a type name.  */
!   /* FIXME: chastain/2003-11-26: block=NULL is bogus.  See pr gdb/1465. */
!   run_time_type = cp_lookup_rtti_type (class_name, NULL);
!   if (run_time_type == NULL)
!     return NULL;
  
    /* Get the offset from VALUE to the top of the complete object.
       NOTE: this is the reverse of the meaning of *TOP_P.  */


^ permalink raw reply	[flat|nested] 11+ messages in thread
end of thread, other threads:[~2003-12-05 17:40 UTC | newest]

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2003-12-05  5:26 [rfa/c++] cp_lookup_rtti_type, take 2 Michael Elizabeth Chastain
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2003-12-05  4:23 Michael Elizabeth Chastain
2003-12-05  5:01 ` Daniel Jacobowitz
2003-12-05 17:12 ` David Carlton
2003-12-05 17:16   ` Daniel Jacobowitz
2003-12-05 17:38     ` David Carlton
2003-12-05 17:40       ` Daniel Jacobowitz
2003-12-01 21:40 Michael Elizabeth Chastain
2003-12-05  3:30 ` Daniel Jacobowitz
2003-12-05 16:57   ` David Carlton
2003-12-05 17:16     ` Daniel Jacobowitz

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