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Use address_from_register in dwarf2-frame.c:read_addr_from_reg 

This patch fixes a problem that prevented use of the Dwarf unwinders on SPU,
because dwarf2-frame.c common code did not support the situation where the
stack and/or frame pointer is maintained in a *vector* register.  This is
because read_addr_from_reg is hard-coded to assume that such pointers can
be read from registers via a simple get_frame_register / unpack_pointer
operation.

Now, there *is* a routine address_from_register that calls into the
appropriate tdep routines to handle pointer values in "weird" registers
like on SPU, but it turns out I cannot simply change dwarf2-frame.c to
use address_from_register.  This is because address_from_register uses
value_from_register to create a (temporary) value, and that routine
at some point calls get_frame_id in order to set up that value's
VALUE_FRAME_ID entry.

However, the dwarf2-frame.c read_addr_from_reg routine will be called
during early unwinding (to unwind the frame's CFA), at which point the
frame's ID is not actually known yet!  This would cause an assert.

On the other hand, we may notice that VALUE_FRAME_ID is only needed in the
value returned by value_from_register if that value is later used as an
lvalue.  But this is obviously never done to the temporary value used in
address_from_register.  So, if we could change address_from_register to
not call value_from_register but instead accept constructing a value
that doesn't have VALUE_FRAME_ID set, things should be fine.

To do that, we can change the value_from_register callback to accept
a FRAME_ID instead of a FRAME; the only existing uses of the FRAME
argument were either to extract its frame ID, or its gdbarch.  (To
keep a way of getting at the latter, we also change the callback's
type from "f" to "m".)  Together with the required follow-on changes
in the existing value_from_register implementations (including the
default one), this seems to fix the problem.

As another minor interface cleanup, I've removed the explicit TYPE
argument from address_from_register.  This routine really always
uses a default pointer type, and in the new implementation it -to
some extent- relies on that fact, in that it will now no longer
handle types that require gdbarch_convert_register_p handling.

gdb:
2014-04-17  Ulrich Weigand  <uweigand@de.ibm.com>

	* gdbarch.sh (value_from_register): Make class "m" instead of "f".
	Replace FRAME argument with FRAME_ID.
	* gdbarch.c, gdbarch.h: Regenerate.
	* findvar.c (default_value_from_register): Add GDBARCH argument;
	replace FRAME by FRAME_ID.  No longer call get_frame_id.
	(value_from_register): Update call to gdbarch_value_from_register.
	* value.h (default_value_from_register): Update prototype.
	* s390-linux-tdep.c (s390_value_from_register): Update interface
	and call to default_value_from_register.
	* spu-tdep.c (spu_value_from_register): Likewise.

	* findvar.c (address_from_register): Remove TYPE argument.
	Do not call value_from_register; use gdbarch_value_from_register
	with null_frame_id instead.
	* value.h (address_from_register): Update prototype.
	* dwarf2-frame.c (read_addr_from_reg): Use address_from_register.
	* dwarf2loc.c (dwarf_expr_read_addr_from_reg): Update for
	address_from_register interface change.
This commit is contained in:
Ulrich Weigand 2014-04-17 14:01:39 +02:00
parent 40d1a503c4
commit 2ed3c037cf
10 changed files with 67 additions and 42 deletions
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21
gdb/ChangeLog
View File

@ -1,3 +1,24 @@
2014-04-17 Ulrich Weigand  <uweigand@de.ibm.com>
* gdbarch.sh (value_from_register): Make class "m" instead of "f".
Replace FRAME argument with FRAME_ID.
* gdbarch.c, gdbarch.h: Regenerate.
* findvar.c (default_value_from_register): Add GDBARCH argument;
replace FRAME by FRAME_ID. No longer call get_frame_id.
(value_from_register): Update call to gdbarch_value_from_register.
* value.h (default_value_from_register): Update prototype.
* s390-linux-tdep.c (s390_value_from_register): Update interface
and call to default_value_from_register.
* spu-tdep.c (spu_value_from_register): Likewise.
* findvar.c (address_from_register): Remove TYPE argument.
Do not call value_from_register; use gdbarch_value_from_register
with null_frame_id instead.
* value.h (address_from_register): Update prototype.
* dwarf2-frame.c (read_addr_from_reg): Use address_from_register.
* dwarf2loc.c (dwarf_expr_read_addr_from_reg): Update for
address_from_register interface change.
2014-04-17 Yao Qi <yao@codesourcery.com>
* gdbtypes.h: Update comments to link to types and macros'

10
gdb/dwarf2-frame.c
View File

@ -291,15 +291,9 @@ read_addr_from_reg (void *baton, int reg)
{
struct frame_info *this_frame = (struct frame_info *) baton;
struct gdbarch *gdbarch = get_frame_arch (this_frame);
int regnum;
gdb_byte *buf;
int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
buf = alloca (register_size (gdbarch, regnum));
get_frame_register (this_frame, regnum, buf);
return unpack_pointer (register_type (gdbarch, regnum), buf);
return address_from_register (regnum, this_frame);
}
/* Implement struct dwarf_expr_context_funcs' "get_reg_value" callback. */

8
gdb/dwarf2loc.c
View File

@ -317,13 +317,9 @@ dwarf_expr_read_addr_from_reg (void *baton, int dwarf_regnum)
{
struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
struct gdbarch *gdbarch = get_frame_arch (debaton->frame);
CORE_ADDR result;
int regnum;
int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_regnum);
regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_regnum);
result = address_from_register (builtin_type (gdbarch)->builtin_data_ptr,
regnum, debaton->frame);
return result;
return address_from_register (regnum, debaton->frame);
}
/* Implement struct dwarf_expr_context_funcs' "get_reg_value" callback. */

34
gdb/findvar.c
View File

@ -625,15 +625,14 @@ read_var_value (struct symbol *var, struct frame_info *frame)
/* Install default attributes for register values. */
struct value *
default_value_from_register (struct type *type, int regnum,
struct frame_info *frame)
default_value_from_register (struct gdbarch *gdbarch, struct type *type,
int regnum, struct frame_id frame_id)
{
struct gdbarch *gdbarch = get_frame_arch (frame);
int len = TYPE_LENGTH (type);
struct value *value = allocate_value (type);
VALUE_LVAL (value) = lval_register;
VALUE_FRAME_ID (value) = get_frame_id (frame);
VALUE_FRAME_ID (value) = frame_id;
VALUE_REGNUM (value) = regnum;
/* Any structure stored in more than one register will always be
@ -741,7 +740,8 @@ value_from_register (struct type *type, int regnum, struct frame_info *frame)
else
{
/* Construct the value. */
v = gdbarch_value_from_register (gdbarch, type, regnum, frame);
v = gdbarch_value_from_register (gdbarch, type,
regnum, get_frame_id (frame));
/* Get the data. */
read_frame_register_value (v, frame);
@ -750,18 +750,30 @@ value_from_register (struct type *type, int regnum, struct frame_info *frame)
return v;
}
/* Return contents of register REGNUM in frame FRAME as address,
interpreted as value of type TYPE. Will abort if register
value is not available. */
/* Return contents of register REGNUM in frame FRAME as address.
Will abort if register value is not available. */
CORE_ADDR
address_from_register (struct type *type, int regnum, struct frame_info *frame)
address_from_register (int regnum, struct frame_info *frame)
{
struct gdbarch *gdbarch = get_frame_arch (frame);
struct type *type = builtin_type (gdbarch)->builtin_data_ptr;
struct value *value;
CORE_ADDR result;
value = value_from_register (type, regnum, frame);
gdb_assert (value);
/* This routine may be called during early unwinding, at a time
where the ID of FRAME is not yet known. Calling value_from_register
would therefore abort in get_frame_id. However, since we only need
a temporary value that is never used as lvalue, we actually do not
really need to set its VALUE_FRAME_ID. Therefore, we re-implement
the core of value_from_register, but use the null_frame_id.
This works only if we do not require a special conversion routine,
which is true for plain pointer types for all current targets. */
gdb_assert (!gdbarch_convert_register_p (gdbarch, regnum, type));
value = gdbarch_value_from_register (gdbarch, type, regnum, null_frame_id);
read_frame_register_value (value, frame);
if (value_optimized_out (value))
{

4
gdb/gdbarch.c
View File

@ -2381,13 +2381,13 @@ set_gdbarch_value_to_register (struct gdbarch *gdbarch,
}
struct value *
gdbarch_value_from_register (struct gdbarch *gdbarch, struct type *type, int regnum, struct frame_info *frame)
gdbarch_value_from_register (struct gdbarch *gdbarch, struct type *type, int regnum, struct frame_id frame_id)
{
gdb_assert (gdbarch != NULL);
gdb_assert (gdbarch->value_from_register != NULL);
if (gdbarch_debug >= 2)
fprintf_unfiltered (gdb_stdlog, "gdbarch_value_from_register called\n");
return gdbarch->value_from_register (type, regnum, frame);
return gdbarch->value_from_register (gdbarch, type, regnum, frame_id);
}
void

6
gdb/gdbarch.h
View File

@ -422,12 +422,12 @@ extern void gdbarch_value_to_register (struct gdbarch *gdbarch, struct frame_inf
extern void set_gdbarch_value_to_register (struct gdbarch *gdbarch, gdbarch_value_to_register_ftype *value_to_register);
/* Construct a value representing the contents of register REGNUM in
frame FRAME, interpreted as type TYPE. The routine needs to
frame FRAME_ID, interpreted as type TYPE. The routine needs to
allocate and return a struct value with all value attributes
(but not the value contents) filled in. */
typedef struct value * (gdbarch_value_from_register_ftype) (struct type *type, int regnum, struct frame_info *frame);
extern struct value * gdbarch_value_from_register (struct gdbarch *gdbarch, struct type *type, int regnum, struct frame_info *frame);
typedef struct value * (gdbarch_value_from_register_ftype) (struct gdbarch *gdbarch, struct type *type, int regnum, struct frame_id frame_id);
extern struct value * gdbarch_value_from_register (struct gdbarch *gdbarch, struct type *type, int regnum, struct frame_id frame_id);
extern void set_gdbarch_value_from_register (struct gdbarch *gdbarch, gdbarch_value_from_register_ftype *value_from_register);
typedef CORE_ADDR (gdbarch_pointer_to_address_ftype) (struct gdbarch *gdbarch, struct type *type, const gdb_byte *buf);

4
gdb/gdbarch.sh
View File

@ -500,10 +500,10 @@ m:int:convert_register_p:int regnum, struct type *type:regnum, type:0:generic_co
f:int:register_to_value:struct frame_info *frame, int regnum, struct type *type, gdb_byte *buf, int *optimizedp, int *unavailablep:frame, regnum, type, buf, optimizedp, unavailablep:0
f:void:value_to_register:struct frame_info *frame, int regnum, struct type *type, const gdb_byte *buf:frame, regnum, type, buf:0
# Construct a value representing the contents of register REGNUM in
# frame FRAME, interpreted as type TYPE. The routine needs to
# frame FRAME_ID, interpreted as type TYPE. The routine needs to
# allocate and return a struct value with all value attributes
# (but not the value contents) filled in.
f:struct value *:value_from_register:struct type *type, int regnum, struct frame_info *frame:type, regnum, frame::default_value_from_register::0
m:struct value *:value_from_register:struct type *type, int regnum, struct frame_id frame_id:type, regnum, frame_id::default_value_from_register::0
#
m:CORE_ADDR:pointer_to_address:struct type *type, const gdb_byte *buf:type, buf::unsigned_pointer_to_address::0
m:void:address_to_pointer:struct type *type, gdb_byte *buf, CORE_ADDR addr:type, buf, addr::unsigned_address_to_pointer::0

8
gdb/s390-linux-tdep.c
View File

@ -380,11 +380,11 @@ s390_pseudo_register_write (struct gdbarch *gdbarch, struct regcache *regcache,
registers, even though we are otherwise a big-endian platform. */
static struct value *
s390_value_from_register (struct type *type, int regnum,
struct frame_info *frame)
s390_value_from_register (struct gdbarch *gdbarch, struct type *type,
int regnum, struct frame_id frame_id)
{
struct value *value = default_value_from_register (type, regnum, frame);
struct value *value = default_value_from_register (gdbarch, type,
regnum, frame_id);
check_typedef (type);
if (regnum >= S390_F0_REGNUM && regnum <= S390_F15_REGNUM

7
gdb/spu-tdep.c
View File

@ -314,10 +314,11 @@ spu_pseudo_register_write (struct gdbarch *gdbarch, struct regcache *regcache,
/* Value conversion -- access scalar values at the preferred slot. */
static struct value *
spu_value_from_register (struct type *type, int regnum,
struct frame_info *frame)
spu_value_from_register (struct gdbarch *gdbarch, struct type *type,
int regnum, struct frame_id frame_id)
{
struct value *value = default_value_from_register (type, regnum, frame);
struct value *value = default_value_from_register (gdbarch, type,
regnum, frame_id);
int len = TYPE_LENGTH (type);
if (regnum < SPU_NUM_GPRS && len < 16)

7
gdb/value.h
View File

@ -579,9 +579,10 @@ extern struct value *value_from_contents_and_address (struct type *,
CORE_ADDR);
extern struct value *value_from_contents (struct type *, const gdb_byte *);
extern struct value *default_value_from_register (struct type *type,
extern struct value *default_value_from_register (struct gdbarch *gdbarch,
struct type *type,
int regnum,
struct frame_info *frame);
struct frame_id frame_id);
extern void read_frame_register_value (struct value *value,
struct frame_info *frame);
@ -589,7 +590,7 @@ extern void read_frame_register_value (struct value *value,
extern struct value *value_from_register (struct type *type, int regnum,
struct frame_info *frame);
extern CORE_ADDR address_from_register (struct type *type, int regnum,
extern CORE_ADDR address_from_register (int regnum,
struct frame_info *frame);
extern struct value *value_of_variable (struct symbol *var,