diff options
| author | Richard Bunt <richard.bunt@arm.com> | 2019-03-06 08:23:00 +0000 |
|---|---|---|
| committer | Richard Bunt <richard.bunt@arm.com> | 2019-03-06 08:24:12 +0000 |
| commit | aa3cfbda2f2af71044949b5692ce51cafb023d13 (patch) | |
| tree | 1cba99e017e03ebdd44207d76fb7d23f0e179fcd /gdb/infcall.c | |
| parent | 2d0d5fc6f085dedd7988b29e58fdc4dc2081472e (diff) | |
| download | gdb-aa3cfbda2f2af71044949b5692ce51cafb023d13.zip gdb-aa3cfbda2f2af71044949b5692ce51cafb023d13.tar.gz gdb-aa3cfbda2f2af71044949b5692ce51cafb023d13.tar.bz2 | |
Fortran function calls with arguments
Prior to this patch, calling functions on the inferior with arguments and
then using these arguments within a function resulted in an invalid
memory access. This is because Fortran arguments are typically passed as
pointers to values.
It is possible to call Fortran functions, but memory must be allocated in
the inferior, so a pointer can be passed to the function, and the
language must be set to C to enable C-style casting. This is cumbersome
and not a pleasant debug experience.
This patch implements the GNU Fortran argument passing conventions with
caveats. Firstly, it does not handle the VALUE attribute as there is
insufficient DWARF information to determine when this is the case.
Secondly, functions with optional parameters can only be called with all
parameters present. Both these cases are marked as KFAILS in the test.
Since the GNU Fortran argument passing convention has been implemented,
there is no guarantee that this patch will work correctly, in all cases,
with other compilers.
Despite these limitations, this patch improves the ease with which
functions can be called in many cases, without taking away the existing
approach of calling with the language set to C.
Regression tested on x86_64, aarch64 and POWER9 with GCC 7.3.0.
Regression tested with Ada on x86_64.
Regression tested with native-extended-gdbserver target board.
gdb/ChangeLog:
* eval.c (evaluate_subexp_standard): Call Fortran argument
wrapping logic.
* f-lang.c (struct value): A value which can be passed into a
Fortran function call.
(fortran_argument_convert): Wrap Fortran arguments in a pointer
where appropriate.
(struct type): Value ready for a Fortran function call.
(fortran_preserve_arg_pointer): Undo check_typedef, the pointer
is needed.
* f-lang.h (fortran_argument_convert): Declaration.
(fortran_preserve_arg_pointer): Declaration.
* infcall.c (value_arg_coerce): Call Fortran argument logic.
gdb/testsuite/ChangeLog:
* gdb.fortran/function-calls.exp: New file.
* gdb.fortran/function-calls.f90: New test.
Diffstat (limited to 'gdb/infcall.c')
| -rw-r--r-- | gdb/infcall.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/gdb/infcall.c b/gdb/infcall.c index e58ba84..0deb37d 100644 --- a/gdb/infcall.c +++ b/gdb/infcall.c @@ -33,6 +33,7 @@ #include "command.h" #include "dummy-frame.h" #include "ada-lang.h" +#include "f-lang.h" #include "gdbthread.h" #include "event-top.h" #include "observable.h" @@ -130,7 +131,7 @@ show_unwind_on_terminating_exception_p (struct ui_file *file, int from_tty, } /* Perform the standard coercions that are specified - for arguments to be passed to C or Ada functions. + for arguments to be passed to C, Ada or Fortran functions. If PARAM_TYPE is non-NULL, it is the expected parameter type. IS_PROTOTYPED is non-zero if the function declaration is prototyped. @@ -146,9 +147,11 @@ value_arg_coerce (struct gdbarch *gdbarch, struct value *arg, struct type *type = param_type ? check_typedef (param_type) : arg_type; - /* Perform any Ada-specific coercion first. */ + /* Perform any Ada- and Fortran-specific coercion first. */ if (current_language->la_language == language_ada) arg = ada_convert_actual (arg, type); + else if (current_language->la_language == language_fortran) + type = fortran_preserve_arg_pointer (arg, type); /* Force the value to the target if we will need its address. At this point, we could allocate arguments on the stack instead of |