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Re: Now I know why we used to swap builtin_type_void.
- From: Jim Blandy <jimb at codesourcery dot com>
- To: gdb-patches at sourceware dot org
- Date: Wed, 06 Dec 2006 12:16:32 -0800
- Subject: Re: Now I know why we used to swap builtin_type_void.
- References: <20061206195227.GA9228@nevyn.them.org>
Daniel Jacobowitz <drow@false.org> writes:
> (top-gdb) p *builtin_type_void_data_ptr
> $24 = {pointer_type = 0x0, reference_type = 0x0, chain = 0x7b50d0,
> instance_flags = 0, length = 8, main_type = 0x7b5100}
> (top-gdb) p current_gdbarch.ptr_bit
> $25 = 32
>
> Because we didn't swap out "void", we followed the cached pointer link
> in builtin_type_void when we tried to create a pointer to void. My
> initial default gdbarch was 64-bit, because I built a 64-bit GDB
> binary. So the cached pointer type is 64-bit.
>
> This is a mess. I think we may need to revert the builtin_type_void
> patch unless you have a better idea.
I've committed the following:
gdb/ChangeLog:
2006-12-06 Jim Blandy <jimb@codesourcery.com>
* gdbtypes.c: Revert 2006-12-05 change, and explain why.
Index: gdb/gdbtypes.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbtypes.c,v
retrieving revision 1.107
diff -u -r1.107 gdbtypes.c
--- gdb/gdbtypes.c 6 Dec 2006 00:57:04 -0000 1.107
+++ gdb/gdbtypes.c 6 Dec 2006 20:14:57 -0000
@@ -3297,6 +3297,10 @@
static void
build_gdbtypes (void)
{
+ builtin_type_void =
+ init_type (TYPE_CODE_VOID, 1,
+ 0,
+ "void", (struct objfile *) NULL);
builtin_type_char =
init_type (TYPE_CODE_INT, TARGET_CHAR_BIT / TARGET_CHAR_BIT,
(TYPE_FLAG_NOSIGN
@@ -3646,10 +3650,9 @@
{
struct cmd_list_element *c;
- builtin_type_void =
- init_type (TYPE_CODE_VOID, 1,
- 0,
- "void", (struct objfile *) NULL);
+ /* FIXME: Why don't the following types need to be arch-swapped?
+ See the comment at the top of the calls to
+ DEPRECATED_REGISTER_GDBARCH_SWAP below. */
builtin_type_int0 =
init_type (TYPE_CODE_INT, 0 / 8,
0,
@@ -3701,7 +3704,14 @@
/* FIXME - For the moment, handle types by swapping them in and out.
Should be using the per-architecture data-pointer and a large
- struct. */
+ struct.
+
+ Note that any type T that we might create a 'T *' type for must
+ be arch-swapped: we cache a type's 'T *' type in the pointer_type
+ field, so if we change architectures but don't swap T, then
+ lookup_pointer_type will start handing out pointer types made for
+ a different architecture. */
+ DEPRECATED_REGISTER_GDBARCH_SWAP (builtin_type_void);
DEPRECATED_REGISTER_GDBARCH_SWAP (builtin_type_char);
DEPRECATED_REGISTER_GDBARCH_SWAP (builtin_type_short);
DEPRECATED_REGISTER_GDBARCH_SWAP (builtin_type_int);
@@ -3744,7 +3754,8 @@
deprecated_register_gdbarch_swap (NULL, 0, build_gdbtypes);
/* Note: These types do not need to be swapped - they are target
- neutral. */
+ neutral. FIXME: Are you sure? See the comment above the calls
+ to DEPRECATED_REGISTER_GDBARCH_SWAP above. */
builtin_type_ieee_single_big =
init_type (TYPE_CODE_FLT, floatformat_ieee_single_big.totalsize / 8,
0, "builtin_type_ieee_single_big", NULL);