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Add gdbarch callback to provide formats for debug info float types

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At this point, all TYPE_CODE_FLT types carry their floating-point format,
except for those creating from reading DWARF or stabs debug info.  Those
will be addressed by this commit.

The main issue here is that we actually have to determine which floating-
point format to use.  Currently, we only have the type length as input
to this decision.  In the future, we may hopefully get --at least in
DWARF-- additional information to help disambiguate multiple different
formats of the same length.  For now, we can still look at the type name
as a hint.

This decision logic is encapsulated in a gdbarch callback to allow
platform-specific overrides.  The default implementation use the same
logic (compare type length against the various gdbarch_..._bit sizes)
that is currently implemented in floatformat_from_length.

With this commit, all platforms still use the default logic, so there
should be no actual change in behavior.  A follow-on commit will add
support for __float128 on Intel and Power.

Once dwarf2read.c and stabsread.c make use of the new callback to
determine floating-point formats, we're now sure every TYPE_CODE_FLT
type will always carry its format.  The commit therefore adds asserts
to verify_floatformat to ensure new code will continue to always
provide formats, and removes the code in floatformat_from_type that
used to handle types with a NULL TYPE_FLOATFORMAT.

gdb/ChangeLog:

	* gdbarch.sh (floatformat_for_type): New gdbarch callback.
	* gdbarch.h, gdbarch.c: Re-generate.
	* arch-utils.h (default_floatformat_for_type): New prototype.
	* arch-utils.c (default_floatformat_for_type): New function.

	* doublest.c (floatformat_from_length): Remove.
	(floatformat_from_type): Assume TYPE_FLOATFORMAT is non-NULL.
	* gdbtypes.c (verify_floatformat): Require non-NULL format.

	* dwarf2read.c (dwarf2_init_float_type): New function.
	(read_base_type): Use it.
	* stabsread.c (dbx_init_float_type): New function.
	(read_sun_floating_type): Use it.
	(read_range_type): Likewise.

Signed-off-by: Ulrich Weigand <ulrich.weigand@de.ibm.com>
This commit is contained in:
Ulrich Weigand 2016-09-06 17:31:53 +02:00
parent 49f190bcb7
commit 9b790ce722
10 changed files with 141 additions and 68 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
gdb/ChangeLog
View File

@ -1,3 +1,20 @@
2016-09-05 Ulrich Weigand <uweigand@de.ibm.com>
* gdbarch.sh (floatformat_for_type): New gdbarch callback.
* gdbarch.h, gdbarch.c: Re-generate.
* arch-utils.h (default_floatformat_for_type): New prototype.
* arch-utils.c (default_floatformat_for_type): New function.
* doublest.c (floatformat_from_length): Remove.
(floatformat_from_type): Assume TYPE_FLOATFORMAT is non-NULL.
* gdbtypes.c (verify_floatformat): Require non-NULL format.
* dwarf2read.c (dwarf2_init_float_type): New function.
(read_base_type): Use it.
* stabsread.c (dbx_init_float_type): New function.
(read_sun_floating_type): Use it.
(read_range_type): Likewise.
2016-09-05 Ulrich Weigand <uweigand@de.ibm.com>
* ada-lang.c (ada_language_arch_info): Use gdbarch-provided

28
gdb/arch-utils.c
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@ -241,6 +241,34 @@ legacy_virtual_frame_pointer (struct gdbarch *gdbarch,
*frame_offset = 0;
}
/* Return a floating-point format for a floating-point variable of
length LEN in bits. If non-NULL, NAME is the name of its type.
If no suitable type is found, return NULL. */
const struct floatformat **
default_floatformat_for_type (struct gdbarch *gdbarch,
const char *name, int len)
{
const struct floatformat **format = NULL;
if (len == gdbarch_half_bit (gdbarch))
format = gdbarch_half_format (gdbarch);
else if (len == gdbarch_float_bit (gdbarch))
format = gdbarch_float_format (gdbarch);
else if (len == gdbarch_double_bit (gdbarch))
format = gdbarch_double_format (gdbarch);
else if (len == gdbarch_long_double_bit (gdbarch))
format = gdbarch_long_double_format (gdbarch);
/* On i386 the 'long double' type takes 96 bits,
while the real number of used bits is only 80,
both in processor and in memory.
The code below accepts the real bit size. */
else if (gdbarch_long_double_format (gdbarch) != NULL
&& len == gdbarch_long_double_format (gdbarch)[0]->totalsize)
format = gdbarch_long_double_format (gdbarch);
return format;
}
int
generic_convert_register_p (struct gdbarch *gdbarch, int regnum,

5
gdb/arch-utils.h
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@ -95,6 +95,11 @@ int cannot_register_not (struct gdbarch *gdbarch, int regnum);
extern gdbarch_virtual_frame_pointer_ftype legacy_virtual_frame_pointer;
/* Default implementation of gdbarch_floatformat_for_type. */
extern const struct floatformat **
default_floatformat_for_type (struct gdbarch *gdbarch,
const char *name, int len);
extern CORE_ADDR generic_skip_trampoline_code (struct frame_info *frame,
CORE_ADDR pc);

55
gdb/doublest.c
View File

@ -770,52 +770,8 @@ floatformat_from_doublest (const struct floatformat *fmt,
}
/* Return a floating-point format for a floating-point variable of
length LEN. If no suitable floating-point format is found, an
error is thrown.
We need this functionality since information about the
floating-point format of a type is not always available to GDB; the
debug information typically only tells us the size of a
floating-point type.
FIXME: kettenis/2001-10-28: In many places, particularly in
target-dependent code, the format of floating-point types is known,
but not passed on by GDB. This should be fixed. */
static const struct floatformat *
floatformat_from_length (struct gdbarch *gdbarch, int len)
{
const struct floatformat *format;
if (len * TARGET_CHAR_BIT == gdbarch_half_bit (gdbarch))
format = gdbarch_half_format (gdbarch)
[gdbarch_byte_order (gdbarch)];
else if (len * TARGET_CHAR_BIT == gdbarch_float_bit (gdbarch))
format = gdbarch_float_format (gdbarch)
[gdbarch_byte_order (gdbarch)];
else if (len * TARGET_CHAR_BIT == gdbarch_double_bit (gdbarch))
format = gdbarch_double_format (gdbarch)
[gdbarch_byte_order (gdbarch)];
else if (len * TARGET_CHAR_BIT == gdbarch_long_double_bit (gdbarch))
format = gdbarch_long_double_format (gdbarch)
[gdbarch_byte_order (gdbarch)];
/* On i386 the 'long double' type takes 96 bits,
while the real number of used bits is only 80,
both in processor and in memory.
The code below accepts the real bit size. */
else if ((gdbarch_long_double_format (gdbarch) != NULL)
&& (len * TARGET_CHAR_BIT
== gdbarch_long_double_format (gdbarch)[0]->totalsize))
format = gdbarch_long_double_format (gdbarch)
[gdbarch_byte_order (gdbarch)];
else
format = NULL;
if (format == NULL)
error (_("Unrecognized %d-bit floating-point type."),
len * TARGET_CHAR_BIT);
return format;
}
/* Return the floating-point format for a floating-point variable of
type TYPE. */
const struct floatformat *
floatformat_from_type (const struct type *type)
@ -824,11 +780,8 @@ floatformat_from_type (const struct type *type)
const struct floatformat *fmt;
gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT);
if (TYPE_FLOATFORMAT (type) != NULL)
fmt = TYPE_FLOATFORMAT (type)[gdbarch_byte_order (gdbarch)];
else
fmt = floatformat_from_length (gdbarch, TYPE_LENGTH (type));
gdb_assert (TYPE_FLOATFORMAT (type));
fmt = TYPE_FLOATFORMAT (type)[gdbarch_byte_order (gdbarch)];
gdb_assert (TYPE_LENGTH (type) >= floatformat_totalsize_bytes (fmt));
return fmt;
}

25
gdb/dwarf2read.c
View File

@ -14757,6 +14757,27 @@ read_typedef (struct die_info *die, struct dwarf2_cu *cu)
return this_type;
}
/* Allocate a floating-point type of size BITS and name NAME. Pass NAME_HINT
(which may be different from NAME) to the architecture back-end to allow
it to guess the correct format if necessary. */
static struct type *
dwarf2_init_float_type (struct objfile *objfile, int bits, const char *name,
const char *name_hint)
{
struct gdbarch *gdbarch = get_objfile_arch (objfile);
const struct floatformat **format;
struct type *type;
format = gdbarch_floatformat_for_type (gdbarch, name_hint, bits);
if (format)
type = init_float_type (objfile, bits, name, format);
else
type = init_type (objfile, TYPE_CODE_ERROR, bits / TARGET_CHAR_BIT, name);
return type;
}
/* Find a representation of a given base type and install
it in the TYPE field of the die. */
@ -14797,14 +14818,14 @@ read_base_type (struct die_info *die, struct dwarf2_cu *cu)
type = init_boolean_type (objfile, bits, 1, name);
break;
case DW_ATE_complex_float:
type = init_float_type (objfile, bits / 2, NULL, NULL);
type = dwarf2_init_float_type (objfile, bits / 2, NULL, name);
type = init_complex_type (objfile, name, type);
break;
case DW_ATE_decimal_float:
type = init_decfloat_type (objfile, bits, name);
break;
case DW_ATE_float:
type = init_float_type (objfile, bits, name, NULL);
type = dwarf2_init_float_type (objfile, bits, name, name);
break;
case DW_ATE_signed:
type = init_integer_type (objfile, bits, 0, name);

23
gdb/gdbarch.c
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@ -176,6 +176,7 @@ struct gdbarch
const struct floatformat ** double_format;
int long_double_bit;
const struct floatformat ** long_double_format;
gdbarch_floatformat_for_type_ftype *floatformat_for_type;
int ptr_bit;
int addr_bit;
int dwarf2_addr_size;
@ -376,6 +377,7 @@ gdbarch_alloc (const struct gdbarch_info *info,
gdbarch->float_bit = 4*TARGET_CHAR_BIT;
gdbarch->double_bit = 8*TARGET_CHAR_BIT;
gdbarch->long_double_bit = 8*TARGET_CHAR_BIT;
gdbarch->floatformat_for_type = default_floatformat_for_type;
gdbarch->ptr_bit = gdbarch->int_bit;
gdbarch->char_signed = -1;
gdbarch->virtual_frame_pointer = legacy_virtual_frame_pointer;
@ -522,6 +524,7 @@ verify_gdbarch (struct gdbarch *gdbarch)
/* Skip verify of long_double_bit, invalid_p == 0 */
if (gdbarch->long_double_format == 0)
gdbarch->long_double_format = floatformats_ieee_double;
/* Skip verify of floatformat_for_type, invalid_p == 0 */
/* Skip verify of ptr_bit, invalid_p == 0 */
if (gdbarch->addr_bit == 0)
gdbarch->addr_bit = gdbarch_ptr_bit (gdbarch);
@ -972,6 +975,9 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
fprintf_unfiltered (file,
"gdbarch_dump: float_format = %s\n",
pformat (gdbarch->float_format));
fprintf_unfiltered (file,
"gdbarch_dump: floatformat_for_type = <%s>\n",
host_address_to_string (gdbarch->floatformat_for_type));
fprintf_unfiltered (file,
"gdbarch_dump: fp0_regnum = %s\n",
plongest (gdbarch->fp0_regnum));
@ -1729,6 +1735,23 @@ set_gdbarch_long_double_format (struct gdbarch *gdbarch,
gdbarch->long_double_format = long_double_format;
}
const struct floatformat **
gdbarch_floatformat_for_type (struct gdbarch *gdbarch, const char *name, int length)
{
gdb_assert (gdbarch != NULL);
gdb_assert (gdbarch->floatformat_for_type != NULL);
if (gdbarch_debug >= 2)
fprintf_unfiltered (gdb_stdlog, "gdbarch_floatformat_for_type called\n");
return gdbarch->floatformat_for_type (gdbarch, name, length);
}
void
set_gdbarch_floatformat_for_type (struct gdbarch *gdbarch,
gdbarch_floatformat_for_type_ftype floatformat_for_type)
{
gdbarch->floatformat_for_type = floatformat_for_type;
}
int
gdbarch_ptr_bit (struct gdbarch *gdbarch)
{

8
gdb/gdbarch.h
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@ -187,6 +187,14 @@ extern void set_gdbarch_long_double_bit (struct gdbarch *gdbarch, int long_doubl
extern const struct floatformat ** gdbarch_long_double_format (struct gdbarch *gdbarch);
extern void set_gdbarch_long_double_format (struct gdbarch *gdbarch, const struct floatformat ** long_double_format);
/* Returns the floating-point format to be used for values of length LENGTH.
NAME, if non-NULL, is the type name, which may be used to distinguish
different target formats of the same length. */
typedef const struct floatformat ** (gdbarch_floatformat_for_type_ftype) (struct gdbarch *gdbarch, const char *name, int length);
extern const struct floatformat ** gdbarch_floatformat_for_type (struct gdbarch *gdbarch, const char *name, int length);
extern void set_gdbarch_floatformat_for_type (struct gdbarch *gdbarch, gdbarch_floatformat_for_type_ftype *floatformat_for_type);
/* For most targets, a pointer on the target and its representation as an
address in GDB have the same size and "look the same". For such a
target, you need only set gdbarch_ptr_bit and gdbarch_addr_bit

5
gdb/gdbarch.sh
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@ -383,6 +383,11 @@ v:const struct floatformat **:double_format:::::floatformats_ieee_double::pforma
v:int:long_double_bit:::8 * sizeof (long double):8*TARGET_CHAR_BIT::0
v:const struct floatformat **:long_double_format:::::floatformats_ieee_double::pformat (gdbarch->long_double_format)
# Returns the floating-point format to be used for values of length LENGTH.
# NAME, if non-NULL, is the type name, which may be used to distinguish
# different target formats of the same length.
m:const struct floatformat **:floatformat_for_type:const char *name, int length:name, length:0:default_floatformat_for_type::0
# For most targets, a pointer on the target and its representation as an
# address in GDB have the same size and "look the same". For such a
# target, you need only set gdbarch_ptr_bit and gdbarch_addr_bit

19
gdb/gdbtypes.c
View File

@ -2712,21 +2712,16 @@ set_type_code (struct type *type, enum type_code code)
static int
verify_floatformat (int bit, const struct floatformat **floatformats)
{
gdb_assert (floatformats != NULL);
gdb_assert (floatformats[0] != NULL && floatformats[1] != NULL);
if (bit == -1)
{
gdb_assert (floatformats != NULL);
gdb_assert (floatformats[0] != NULL && floatformats[1] != NULL);
bit = floatformats[0]->totalsize;
}
bit = floatformats[0]->totalsize;
gdb_assert (bit >= 0);
if (floatformats != NULL)
{
size_t len = bit / TARGET_CHAR_BIT;
gdb_assert (len >= floatformat_totalsize_bytes (floatformats[0]));
gdb_assert (len >= floatformat_totalsize_bytes (floatformats[1]));
}
size_t len = bit / TARGET_CHAR_BIT;
gdb_assert (len >= floatformat_totalsize_bytes (floatformats[0]));
gdb_assert (len >= floatformat_totalsize_bytes (floatformats[1]));
return bit;
}

24
gdb/stabsread.c
View File

@ -353,6 +353,24 @@ dbx_alloc_type (int typenums[2], struct objfile *objfile)
return (*type_addr);
}
/* Allocate a floating-point type of size BITS. */
static struct type *
dbx_init_float_type (struct objfile *objfile, int bits)
{
struct gdbarch *gdbarch = get_objfile_arch (objfile);
const struct floatformat **format;
struct type *type;
format = gdbarch_floatformat_for_type (gdbarch, NULL, bits);
if (format)
type = init_float_type (objfile, bits, NULL, format);
else
type = init_type (objfile, TYPE_CODE_ERROR, bits / TARGET_CHAR_BIT, NULL);
return type;
}
/* for all the stabs in a given stab vector, build appropriate types
and fix their symbols in given symbol vector. */
@ -3847,11 +3865,11 @@ read_sun_floating_type (char **pp, int typenums[2], struct objfile *objfile)
if (details == NF_COMPLEX || details == NF_COMPLEX16
|| details == NF_COMPLEX32)
{
rettype = init_float_type (objfile, nbits / 2, NULL, NULL);
rettype = dbx_init_float_type (objfile, nbits / 2);
return init_complex_type (objfile, NULL, rettype);
}
return init_float_type (objfile, nbits, NULL, NULL);
return dbx_init_float_type (objfile, nbits);
}
/* Read a number from the string pointed to by *PP.
@ -4138,7 +4156,7 @@ read_range_type (char **pp, int typenums[2], int type_size,
if (n3 == 0 && n2 > 0)
{
struct type *float_type
= init_float_type (objfile, n2 * TARGET_CHAR_BIT, NULL, NULL);
= dbx_init_float_type (objfile, n2 * TARGET_CHAR_BIT);
if (self_subrange)
return init_complex_type (objfile, NULL, float_type);