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gdb/fortran: add support for parsing array strides in expressions

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With this commit GDB now understands the syntax of Fortran array
strides, a user can type an expression including an array stride, but
they will only get an error informing them that array strides are not
supported.

This alone is an improvement on what we had before in GDB, better to
give the user a helpful message that a particular feature is not
supported than to just claim a syntax error.

Before:

  (gdb) p array (1:10:2, 2:10:2)
  A syntax error in expression, near `:2, 2:10:2)'.

Now:

  (gdb) p array (1:10:2, 2:10:2)
  Fortran array strides are not currently supported

Later commits will allow GDB to handle array strides correctly.

gdb/ChangeLog:

	* expprint.c (dump_subexp_body_standard): Print RANGE_HAS_STRIDE.
	* expression.h (enum range_type): Add RANGE_HAS_STRIDE.
	* f-exp.y (arglist): Allow for a series of subranges.
	(subrange): Add cases for subranges with strides.
	* f-lang.c (value_f90_subarray): Catch use of array strides and
	throw an error.
	* parse.c (operator_length_standard): Handle RANGE_HAS_STRIDE.

gdb/testsuite/ChangeLog:

	* gdb.fortran/array-slices.exp: Add a new test.
This commit is contained in:
Andrew Burgess 2020-10-08 16:34:58 +01:00
parent f2d8e4c597
commit 6b4c676cc7
8 changed files with 84 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
gdb/ChangeLog
View file

@ -1,3 +1,13 @@
2020-10-22 Andrew Burgess <andrew.burgess@embecosm.com>
* expprint.c (dump_subexp_body_standard): Print RANGE_HAS_STRIDE.
* expression.h (enum range_type): Add RANGE_HAS_STRIDE.
* f-exp.y (arglist): Allow for a series of subranges.
(subrange): Add cases for subranges with strides.
* f-lang.c (value_f90_subarray): Catch use of array strides and
throw an error.
* parse.c (operator_length_standard): Handle RANGE_HAS_STRIDE.
2020-10-22 Andrew Burgess <andrew.burgess@embecosm.com>
* expprint.c (print_subexp_standard): Change enum range_type to

4
gdb/expprint.c
View file

@ -1120,12 +1120,16 @@ dump_subexp_body_standard (struct expression *exp,
fputs_filtered ("..", stream);
if (!(range_flag & RANGE_HIGH_BOUND_DEFAULT))
fputs_filtered ("EXP", stream);
if (range_flag & RANGE_HAS_STRIDE)
fputs_filtered (":EXP", stream);
fputs_filtered ("'", stream);
if (!(range_flag & RANGE_LOW_BOUND_DEFAULT))
elt = dump_subexp (exp, stream, elt);
if (!(range_flag & RANGE_HIGH_BOUND_DEFAULT))
elt = dump_subexp (exp, stream, elt);
if (range_flag & RANGE_HAS_STRIDE)
elt = dump_subexp (exp, stream, elt);
}
break;

3
gdb/expression.h
View file

@ -199,6 +199,9 @@ enum range_flag : unsigned
/* The high bound of this range is exclusive. */
RANGE_HIGH_BOUND_EXCLUSIVE = 1 << 2,
/* The range has a stride. */
RANGE_HAS_STRIDE = 1 << 3,
};
DEF_ENUM_FLAGS_TYPE (enum range_flag, range_flags);

36
gdb/f-exp.y
View file

@ -284,6 +284,10 @@ arglist : arglist ',' exp %prec ABOVE_COMMA
{ pstate->arglist_len++; }
;
arglist : arglist ',' subrange %prec ABOVE_COMMA
{ pstate->arglist_len++; }
;
/* There are four sorts of subrange types in F90. */
subrange: exp ':' exp %prec ABOVE_COMMA
@ -314,6 +318,38 @@ subrange: ':' %prec ABOVE_COMMA
write_exp_elt_opcode (pstate, OP_RANGE); }
;
/* And each of the four subrange types can also have a stride. */
subrange: exp ':' exp ':' exp %prec ABOVE_COMMA
{ write_exp_elt_opcode (pstate, OP_RANGE);
write_exp_elt_longcst (pstate, RANGE_HAS_STRIDE);
write_exp_elt_opcode (pstate, OP_RANGE); }
;
subrange: exp ':' ':' exp %prec ABOVE_COMMA
{ write_exp_elt_opcode (pstate, OP_RANGE);
write_exp_elt_longcst (pstate,
(RANGE_HIGH_BOUND_DEFAULT
| RANGE_HAS_STRIDE));
write_exp_elt_opcode (pstate, OP_RANGE); }
;
subrange: ':' exp ':' exp %prec ABOVE_COMMA
{ write_exp_elt_opcode (pstate, OP_RANGE);
write_exp_elt_longcst (pstate,
(RANGE_LOW_BOUND_DEFAULT
| RANGE_HAS_STRIDE));
write_exp_elt_opcode (pstate, OP_RANGE); }
;
subrange: ':' ':' exp %prec ABOVE_COMMA
{ write_exp_elt_opcode (pstate, OP_RANGE);
write_exp_elt_longcst (pstate,
(RANGE_LOW_BOUND_DEFAULT
| RANGE_HIGH_BOUND_DEFAULT
| RANGE_HAS_STRIDE));
write_exp_elt_opcode (pstate, OP_RANGE); }
;
complexnum: exp ',' exp
{ }
;

10
gdb/f-lang.c
View file

@ -124,7 +124,7 @@ value_f90_subarray (struct value *array,
struct expression *exp, int *pos, enum noside noside)
{
int pc = (*pos) + 1;
LONGEST low_bound, high_bound;
LONGEST low_bound, high_bound, stride;
struct type *range = check_typedef (value_type (array)->index_type ());
enum range_flag range_flag
= (enum range_flag) longest_to_int (exp->elts[pc].longconst);
@ -141,6 +141,14 @@ value_f90_subarray (struct value *array,
else
high_bound = value_as_long (evaluate_subexp (nullptr, exp, pos, noside));
if (range_flag & RANGE_HAS_STRIDE)
stride = value_as_long (evaluate_subexp (nullptr, exp, pos, noside));
else
stride = 1;
if (stride != 1)
error (_("Fortran array strides are not currently supported"));
return value_slice (array, low_bound, high_bound - low_bound + 1);
}

2
gdb/parse.c
View file

@ -924,6 +924,8 @@ operator_length_standard (const struct expression *expr, int endpos,
/* Assume the range has 2 arguments (low bound and high bound), then
reduce the argument count if any bounds are set to default. */
args = 2;
if (range_flag & RANGE_HAS_STRIDE)
++args;
if (range_flag & RANGE_LOW_BOUND_DEFAULT)
--args;
if (range_flag & RANGE_HIGH_BOUND_DEFAULT)

4
gdb/testsuite/ChangeLog
View file

@ -1,3 +1,7 @@
2020-10-22 Andrew Burgess <andrew.burgess@embecosm.com>
* gdb.fortran/array-slices.exp: Add a new test.
2020-10-21 Gary Benson <gbenson@redhat.com>
* gdb.mi/mi-fullname-deleted.exp: Fix substituted

16
gdb/testsuite/gdb.fortran/array-slices.exp
View file

@ -69,3 +69,19 @@ foreach result $array_contents msg $message_strings {
}
gdb_continue_to_breakpoint "continue to Final Breakpoint"
# Next test that asking for an array with stride at the CLI gives an
# error.
clean_restart ${testfile}
if ![fortran_runto_main] then {
perror "couldn't run to main"
continue
}
gdb_breakpoint "show"
gdb_continue_to_breakpoint "show"
gdb_test "up" ".*"
gdb_test "p array (1:10:2, 1:10:2)" \
"Fortran array strides are not currently supported" \
"using array stride gives an error"