[RFA,6/6] Remove long_long_align_bit gdbarch attribute
Commit Message
This removes the long_long_align_bit gdbarch attribute in favor of
type_align. This uncovered two possible issues.
First, arc-tdep.c claimed that long long alignment was 32 bits, but
gcc's arc.h says:
#define ADJUST_FIELD_ALIGN(FIELD, TYPE, COMPUTED) \
(TYPE_MODE (strip_array_types (TYPE)) == DFmode \
? MIN ((COMPUTED), 32) : (COMPUTED))
Here, DFmode means "double". So, I've implemented arc_type_align
according to this. I do not have a good way to test this.
Second, jit.c, the sole user of long_long_align_bit, was confusing
"long long" with uint64_t. The relevant structure is defined in the
JIT API part of the manual as:
struct jit_code_entry
{
struct jit_code_entry *next_entry;
struct jit_code_entry *prev_entry;
const char *symfile_addr;
uint64_t symfile_size;
};
I've changed this code to use uint64_t.
2018-04-24 Tom Tromey <tom@tromey.com>
* jit.c (jit_read_code_entry): Use type_align.
* i386-tdep.c (i386_gdbarch_init): Don't call
set_gdbarch_long_long_align_bit.
* gdbarch.sh: Remove long_long_align_bit.
* gdbarch.c, gdbarch.h: Rebuild.
* arc-tdep.c (arc_type_align): New function.
(arc_gdbarch_init): Use arc_type_align. Don't call
set_gdbarch_long_long_align_bit.
---
gdb/ChangeLog | 11 +++++++++++
gdb/arc-tdep.c | 15 ++++++++++++++-
gdb/gdbarch.c | 23 -----------------------
gdb/gdbarch.h | 6 ------
gdb/gdbarch.sh | 3 ---
gdb/i386-tdep.c | 1 -
gdb/jit.c | 4 ++--
7 files changed, 27 insertions(+), 36 deletions(-)
Comments
>>>>> "Tom" == Tom Tromey <tom@tromey.com> writes:
Tom> This removes the long_long_align_bit gdbarch attribute in favor of
Tom> type_align. This uncovered two possible issues.
Tom> First, arc-tdep.c claimed that long long alignment was 32 bits, but
Tom> gcc's arc.h says:
Tom> #define ADJUST_FIELD_ALIGN(FIELD, TYPE, COMPUTED) \
Tom> (TYPE_MODE (strip_array_types (TYPE)) == DFmode \
Tom> ? MIN ((COMPUTED), 32) : (COMPUTED))
Tom> Here, DFmode means "double". So, I've implemented arc_type_align
Tom> according to this. I do not have a good way to test this.
Anton, could you take a look at this part of the patch?
Tom
> First, arc-tdep.c claimed that long long alignment was 32 bits, but gcc's arc.h
> says:
>
> #define ADJUST_FIELD_ALIGN(FIELD, TYPE, COMPUTED) \
> (TYPE_MODE (strip_array_types (TYPE)) == DFmode \
> ? MIN ((COMPUTED), 32) : (COMPUTED))
>
> Here, DFmode means "double". So, I've implemented arc_type_align
> according to this. I do not have a good way to test this.
>
> diff --git a/gdb/arc-tdep.c b/gdb/arc-tdep.c index b0d51addd3..86cf522443
> 100644
> --- a/gdb/arc-tdep.c
> +++ b/gdb/arc-tdep.c
> @@ -1957,6 +1957,19 @@ arc_tdesc_init (struct gdbarch_info info, const
> struct target_desc **tdesc,
> return TRUE;
> }
>
> +/* Implement the type_align gdbarch function. */
> +
> +static ULONGEST
> +arc_type_align (struct gdbarch *gdbarch, struct type *type) {
> + type = check_typedef (type);
> +
> + if (TYPE_CODE (type) == TYPE_CODE_FLT && TYPE_LENGTH (type) == 8)
> + return 4;
> +
> + return TYPE_LENGTH (type);
> +}
> +
Hi Tom,
If I read this correctly, then it would set 4 byte alignment only to 8 byte
floating point type? That doesn't look right, because on ARC there is never
more than 4 byte alignment for any data type. GCC arc.h has:
#define BIGGEST_ALIGNMENT 32
According to comments it used to be 64, but was changed to 32 at some
undefined point in the past.
I would have implemented this as:
static ULONGEST
arc_type_align (struct gdbarch *gdbarch, struct type *type) {
type = check_typedef (type);
return std::min<ULONGEST>(4, TYPE_LENGTH (type));
}
Anton
>>>>> "Anton" == Anton Kolesov <Anton.Kolesov@synopsys.com> writes:
Anton> I would have implemented this as:
Anton> static ULONGEST
Anton> arc_type_align (struct gdbarch *gdbarch, struct type *type) {
Anton> type = check_typedef (type);
Anton> return std::min<ULONGEST>(4, TYPE_LENGTH (type));
Anton> }
Thanks, I've made this change locally.
Tom
@@ -1,3 +1,14 @@
+2018-04-24 Tom Tromey <tom@tromey.com>
+
+ * jit.c (jit_read_code_entry): Use type_align.
+ * i386-tdep.c (i386_gdbarch_init): Don't call
+ set_gdbarch_long_long_align_bit.
+ * gdbarch.sh: Remove long_long_align_bit.
+ * gdbarch.c, gdbarch.h: Rebuild.
+ * arc-tdep.c (arc_type_align): New function.
+ (arc_gdbarch_init): Use arc_type_align. Don't call
+ set_gdbarch_long_long_align_bit.
+
2018-04-24 Tom Tromey <tom@tromey.com>
* rust-lang.c (rust_type_alignment): Remove.
@@ -1957,6 +1957,19 @@ arc_tdesc_init (struct gdbarch_info info, const struct target_desc **tdesc,
return TRUE;
}
+/* Implement the type_align gdbarch function. */
+
+static ULONGEST
+arc_type_align (struct gdbarch *gdbarch, struct type *type)
+{
+ type = check_typedef (type);
+
+ if (TYPE_CODE (type) == TYPE_CODE_FLT && TYPE_LENGTH (type) == 8)
+ return 4;
+
+ return TYPE_LENGTH (type);
+}
+
/* Implement the "init" gdbarch method. */
static struct gdbarch *
@@ -1982,7 +1995,7 @@ arc_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
set_gdbarch_int_bit (gdbarch, 32);
set_gdbarch_long_bit (gdbarch, 32);
set_gdbarch_long_long_bit (gdbarch, 64);
- set_gdbarch_long_long_align_bit (gdbarch, 32);
+ set_gdbarch_type_align (gdbarch, arc_type_align);
set_gdbarch_float_bit (gdbarch, 32);
set_gdbarch_float_format (gdbarch, floatformats_ieee_single);
set_gdbarch_double_bit (gdbarch, 64);
@@ -175,7 +175,6 @@ struct gdbarch
int int_bit;
int long_bit;
int long_long_bit;
- int long_long_align_bit;
int half_bit;
const struct floatformat ** half_format;
int float_bit;
@@ -389,7 +388,6 @@ gdbarch_alloc (const struct gdbarch_info *info,
gdbarch->int_bit = 4*TARGET_CHAR_BIT;
gdbarch->long_bit = 4*TARGET_CHAR_BIT;
gdbarch->long_long_bit = 2*gdbarch->long_bit;
- gdbarch->long_long_align_bit = 2*gdbarch->long_bit;
gdbarch->half_bit = 2*TARGET_CHAR_BIT;
gdbarch->float_bit = 4*TARGET_CHAR_BIT;
gdbarch->double_bit = 8*TARGET_CHAR_BIT;
@@ -530,7 +528,6 @@ verify_gdbarch (struct gdbarch *gdbarch)
/* Skip verify of int_bit, invalid_p == 0 */
/* Skip verify of long_bit, invalid_p == 0 */
/* Skip verify of long_long_bit, invalid_p == 0 */
- /* Skip verify of long_long_align_bit, invalid_p == 0 */
/* Skip verify of half_bit, invalid_p == 0 */
if (gdbarch->half_format == 0)
gdbarch->half_format = floatformats_ieee_half;
@@ -1165,9 +1162,6 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
fprintf_unfiltered (file,
"gdbarch_dump: long_double_format = %s\n",
pformat (gdbarch->long_double_format));
- fprintf_unfiltered (file,
- "gdbarch_dump: long_long_align_bit = %s\n",
- plongest (gdbarch->long_long_align_bit));
fprintf_unfiltered (file,
"gdbarch_dump: long_long_bit = %s\n",
plongest (gdbarch->long_long_bit));
@@ -1638,23 +1632,6 @@ set_gdbarch_long_long_bit (struct gdbarch *gdbarch,
gdbarch->long_long_bit = long_long_bit;
}
-int
-gdbarch_long_long_align_bit (struct gdbarch *gdbarch)
-{
- gdb_assert (gdbarch != NULL);
- /* Skip verify of long_long_align_bit, invalid_p == 0 */
- if (gdbarch_debug >= 2)
- fprintf_unfiltered (gdb_stdlog, "gdbarch_long_long_align_bit called\n");
- return gdbarch->long_long_align_bit;
-}
-
-void
-set_gdbarch_long_long_align_bit (struct gdbarch *gdbarch,
- int long_long_align_bit)
-{
- gdbarch->long_long_align_bit = long_long_align_bit;
-}
-
int
gdbarch_half_bit (struct gdbarch *gdbarch)
{
@@ -147,12 +147,6 @@ extern void set_gdbarch_long_bit (struct gdbarch *gdbarch, int long_bit);
extern int gdbarch_long_long_bit (struct gdbarch *gdbarch);
extern void set_gdbarch_long_long_bit (struct gdbarch *gdbarch, int long_long_bit);
-/* Alignment of a long long or unsigned long long for the target
- machine. */
-
-extern int gdbarch_long_long_align_bit (struct gdbarch *gdbarch);
-extern void set_gdbarch_long_long_align_bit (struct gdbarch *gdbarch, int long_long_align_bit);
-
/* The ABI default bit-size and format for "half", "float", "double", and
"long double". These bit/format pairs should eventually be combined
into a single object. For the moment, just initialize them as a pair.
@@ -360,9 +360,6 @@ v;int;long_bit;;;8 * sizeof (long);4*TARGET_CHAR_BIT;;0
# Number of bits in a long long or unsigned long long for the target
# machine.
v;int;long_long_bit;;;8 * sizeof (LONGEST);2*gdbarch->long_bit;;0
-# Alignment of a long long or unsigned long long for the target
-# machine.
-v;int;long_long_align_bit;;;8 * sizeof (LONGEST);2*gdbarch->long_bit;;0
# The ABI default bit-size and format for "half", "float", "double", and
# "long double". These bit/format pairs should eventually be combined
@@ -8431,7 +8431,6 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
tdep->record_regmap = i386_record_regmap;
- set_gdbarch_long_long_align_bit (gdbarch, 32);
set_gdbarch_type_align (gdbarch, i386_type_align);
/* The format used for `long double' on almost all i386 targets is
@@ -413,8 +413,8 @@ jit_read_code_entry (struct gdbarch *gdbarch,
ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
ptr_size = TYPE_LENGTH (ptr_type);
- /* Figure out where the longlong value will be. */
- align_bytes = gdbarch_long_long_align_bit (gdbarch) / 8;
+ /* Figure out where the uint64_t value will be. */
+ align_bytes = type_align (builtin_type (gdbarch)->builtin_uint64);
off = 3 * ptr_size;
off = (off + (align_bytes - 1)) & ~(align_bytes - 1);