[PATCH v2 0/2] gdb/fortran: add support for accessing fields of extended types

[PATCH v2 0/2] gdb/fortran: add support for accessing fields of extended types

[Nils-Christian Kempke]

Hi all,

V1 of these patches can be found here:

https://sourceware.org/pipermail/gdb-patches/2022-January/185103.html

Changes since V1 only relate to patch one of this series (since patch
was already approved).  After the
discussion here

https://sourceware.org/pipermail/gdb-patches/2022-January/185186.html

I for now opted for only resolving to a type name of an inherited
structure when the language is actually set to Fortran.  The other two
options of 'resolving Fortran structs elsewhere' or 'adding a language
specific query method' seemed overly complicated to me.  Still, if
anyone has objections/favors a different approach I'm happy do change
the implementation.

So the changes to V1 of this series are:
	* PATCH 1/2: add language check to limit the member access by
	base name to Fortran only.
	* PATCH 2/2: no changes.

Thanks,

Nils

Bernhard Heckel (2):
  gdb/fortran: add support for accessing fields of extended types
  gdb/fortran: print fortran extended types with ptype

 gdb/f-exp.y                                   |   7 +-
 gdb/f-lang.h                                  |  11 +
 gdb/f-typeprint.c                             |  24 ++-
 gdb/testsuite/gdb.fortran/oop_extend_type.exp | 190 ++++++++++++++++++
 gdb/testsuite/gdb.fortran/oop_extend_type.f90 |  69 +++++++
 gdb/valops.c                                  |   9 +
 6 files changed, 306 insertions(+), 4 deletions(-)
 create mode 100755 gdb/testsuite/gdb.fortran/oop_extend_type.exp
 create mode 100755 gdb/testsuite/gdb.fortran/oop_extend_type.f90

-- 
2.25.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v2 1/2] gdb/fortran: add support for accessing fields of extended types

[Nils-Christian Kempke]

Fortran 2003 supports type extension.  This patch allows access
to inherited members by using their fully qualified name as described
in the Fortran standard.

In doing so the patch also fixes a bug in GDB when trying to access the
members of a base class in a derived class via the derived class' base
class member.

This patch fixes PR22497 and PR26373 on GDB side.

Using the example Fortran program from PR22497

program mvce
  implicit none

  type :: my_type
     integer :: my_int
  end type my_type

  type, extends(my_type) :: extended_type
  end type extended_type

  type(my_type) :: foo
  type(extended_type) :: bar

  foo%my_int = 0
  bar%my_int = 1

  print*, foo, bar

end program mvce

and running this with GDB and setting a BP at 17:

Before:
(gdb) p bar%my_type
A syntax error in expression, near `my_type'.
(gdb) p bar%my_int
There is no member named my_int.
(gdb) p bar%my_type%my_int
A syntax error in expression, near `my_type%my_int'.
(gdb) p bar
$1 = ( my_type = ( my_int = 1 ) )

After:
(gdb) p bar%my_type
$1 = ( my_int = 1 )
(gdb) p bar%my_int
$2 = 1                 # this line requires DW_TAG_inheritance to work
(gdb) p bar%my_type%my_int
$3 = 1
(gdb) p bar
$4 = ( my_type = ( my_int = 1 ) )

In the above example "p bar%my_int" requires the compiler to emit
information about the inheritance relationship between extended_type
and my_type which gfortran and flang currently do not de.  The
respective issue gcc/49475 has been put as kfail.

Co-authored-by: Nils-Christian Kempke <nils-christian.kempke@intel.com>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=26373
     https://sourceware.org/bugzilla/show_bug.cgi?id=22497
---
 gdb/f-exp.y                                   |   7 +-
 gdb/testsuite/gdb.fortran/oop_extend_type.exp | 159 ++++++++++++++++++
 gdb/testsuite/gdb.fortran/oop_extend_type.f90 |  69 ++++++++
 gdb/valops.c                                  |   9 +
 4 files changed, 242 insertions(+), 2 deletions(-)
 create mode 100755 gdb/testsuite/gdb.fortran/oop_extend_type.exp
 create mode 100755 gdb/testsuite/gdb.fortran/oop_extend_type.f90

diff --git a/gdb/f-exp.y b/gdb/f-exp.y
index 9cba30f683..f9622e63fb 100644
--- a/gdb/f-exp.y
+++ b/gdb/f-exp.y
@@ -808,8 +808,11 @@ nonempty_typelist
 		}
 	;
 
-name	:	NAME
-		{  $$ = $1.stoken; }
+name
+	:	NAME
+		{ $$ = $1.stoken; }
+	|	TYPENAME
+		{ $$ = $1.stoken; }
 	;
 
 name_not_typename :	NAME
diff --git a/gdb/testsuite/gdb.fortran/oop_extend_type.exp b/gdb/testsuite/gdb.fortran/oop_extend_type.exp
new file mode 100755
index 0000000000..5d73e14a56
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/oop_extend_type.exp
@@ -0,0 +1,159 @@
+# Copyright 2016 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+standard_testfile ".f90"
+load_lib "fortran.exp"
+
+if { [skip_fortran_tests] } {
+    return -1
+}
+
+if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile} \
+     {debug f90 quiet}] } {
+	 return -1
+}
+
+if ![fortran_runto_main] {
+    perror "could not run to main"
+    return -1
+}
+
+# Depending on the compiler being used, the type names can be printed differently.
+set real [fortran_real4]
+set logical [fortran_logical4]
+
+set line1 [gdb_get_line_number "! Before vla allocation"]
+gdb_breakpoint $line1
+gdb_continue_to_breakpoint "line1" ".*$srcfile:$line1.*"
+
+gdb_test "whatis wp_vla" "type = Type waypoint, allocatable \\(:\\)" \
+    "whatis wp_vla before allocation"
+
+set line2 [gdb_get_line_number "! After value assignment"]
+gdb_breakpoint $line2
+gdb_continue_to_breakpoint "line2" ".*$srcfile:$line2.*"
+
+# test print of wp
+set test "p wp%coo"
+gdb_test_multiple "$test" "$test" {
+    -re " = \\(1, 2, 1\\)\r\n$gdb_prompt $" {
+      pass "$test"
+    }
+    -re "There is no member named coo.\r\n$gdb_prompt $" {
+      kfail "gcc/49475" "$test"
+    }
+}
+gdb_test "p wp%point%coo" " = \\(1, 2, 1\\)"
+gdb_test "p wp%point" " = \\( coo = \\(1, 2, 1\\) \\)"
+gdb_test "p wp" " = \\( point = \\( coo = \\(1, 2, 1\\) \\), angle = 100 \\)"
+
+gdb_test "whatis wp" "type = Type waypoint"
+gdb_test "ptype wp" \
+  [multi_line "type = Type waypoint" \
+	      "    Type point :: point" \
+	      "    $real :: angle" \
+	      "End Type waypoint"]
+
+set test "ptype wp%coo"
+gdb_test_multiple "$test" "$test" {
+    -re "$real \\(3\\)\r\n$gdb_prompt $" {
+      pass "$test"
+    }
+    -re "There is no member named coo.\r\n$gdb_prompt $" {
+      kfail "gcc/49475" "$test"
+    }
+}
+gdb_test "ptype wp%point%coo" "$real \\(3\\)"
+
+# test print of fwp
+set test "p fwp%coo"
+gdb_test_multiple "$test" "$test" {
+    -re " = \\(1, 2, 2\\)\r\n$gdb_prompt $" {
+      pass "$test"
+    }
+    -re "There is no member named coo.\r\n$gdb_prompt $" {
+      kfail "gcc/49475" "$test"
+    }
+}
+gdb_test "p fwp%waypoint%point%coo" " = \\(1, 2, 2\\)"
+gdb_test "p fwp%waypoint%point" " = \\( coo = \\(1, 2, 2\\) \\)"
+gdb_test "p fwp%waypoint" \
+    " = \\( point = \\( coo = \\(1, 2, 2\\) \\), angle = 10 \\)"
+gdb_test "p fwp" \
+    " = \\( waypoint = \\( point = \\( coo = \\(1, 2, 2\\) \\), angle = 10 \\), is_fancy = \.TRUE\. \\)"
+
+set test "p fwp%angle"
+gdb_test_multiple "$test" "$test" {
+    -re " = 10\r\n$gdb_prompt $" {
+      pass "$test"
+    }
+    -re "There is no member named angle.\r\n$gdb_prompt $" {
+      kfail "gcc/49475" "$test"
+    }
+}
+
+gdb_test "whatis fwp" "type = Type fancywaypoint"
+gdb_test "ptype fwp" \
+  [multi_line "type = Type fancywaypoint" \
+	      "    Type waypoint :: waypoint" \
+	      "    $logical :: is_fancy" \
+	      "End Type fancywaypoint"]
+
+set test "ptype fwp%coo"
+gdb_test_multiple "$test" "$test" {
+    -re "$real \\(3\\)\r\n$gdb_prompt $" {
+      pass "$test"
+    }
+    -re "There is no member named coo.\r\n$gdb_prompt $" {
+      kfail "gcc/49475" "$test"
+    }
+}
+gdb_test "ptype fwp%waypoint%point%coo" "$real \\(3\\)"
+
+# test print of wp_vla
+set test "p wp_vla(1)%coo"
+gdb_test_multiple "$test" "$test" {
+    -re " = \\(10, 12, 10\\)\r\n$gdb_prompt $" {
+      pass "$test"
+    }
+    -re "There is no member named coo.\r\n$gdb_prompt $" {
+      kfail "gcc/49475" "$test"
+    }
+}
+
+gdb_test "p wp_vla(1)%point%coo" " = \\(10, 12, 10\\)"
+gdb_test "p wp_vla(1)%point" " = \\( coo = \\(10, 12, 10\\) \\)"
+gdb_test "p wp_vla(1)" " = \\( point = \\( coo = \\(10, 12, 10\\) \\), angle = 101 \\)"
+
+gdb_test "whatis wp_vla" "type = Type waypoint, allocatable \\(3\\)" \
+    "whatis wp_vla after allocation"
+
+gdb_test "ptype wp_vla" \
+  [multi_line "type = Type waypoint" \
+	      "    Type point :: point" \
+	      "    $real :: angle" \
+	      "End Type waypoint, allocatable \\(3\\)"]
+
+set test "ptype wp_vla(1)%coo"
+gdb_test_multiple "$test" "$test" {
+    -re "$real \\(3\\)\r\n$gdb_prompt $" {
+      pass "$test"
+    }
+    -re "There is no member named coo.\r\n$gdb_prompt $" {
+      kfail "gcc/49475" "$test"
+    }
+}
+
+gdb_test "ptype wp_vla(1)%point%coo" "$real \\(3\\)"
diff --git a/gdb/testsuite/gdb.fortran/oop_extend_type.f90 b/gdb/testsuite/gdb.fortran/oop_extend_type.f90
new file mode 100755
index 0000000000..dc91c45c60
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/oop_extend_type.f90
@@ -0,0 +1,69 @@
+! Copyright 2022 Free Software Foundation, Inc.
+!
+! This program is free software; you can redistribute it and/or modify
+! it under the terms of the GNU General Public License as published by
+! the Free Software Foundation; either version 3 of the License, or
+! (at your option) any later version.
+!
+! This program is distributed in the hope that it will be useful,
+! but WITHOUT ANY WARRANTY; without even the implied warranty of
+! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+! GNU General Public License for more details.
+!
+! You should have received a copy of the GNU General Public License
+! along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+! Test fortran extends feature (also for chained extends).
+module testmod
+    implicit none
+    type :: point
+	real :: coo(3)
+    end type
+
+    type, extends(point) :: waypoint
+	real :: angle
+    end type
+
+    type, extends(waypoint) :: fancywaypoint
+	logical :: is_fancy
+    end type
+end module
+
+program testprog
+    use testmod
+    implicit none
+
+    logical l
+    type(waypoint) :: wp
+    type(fancywaypoint) :: fwp
+    type(waypoint), allocatable :: wp_vla(:)
+
+    l = .FALSE.
+    allocate(wp_vla(3)) ! Before vla allocation
+
+    l = allocated(wp_vla) ! After vla allocation
+
+    wp%angle = 100.00
+    wp%coo(:) = 1.00
+    wp%coo(2) = 2.00
+
+    fwp%is_fancy = .TRUE.
+    fwp%angle = 10.00
+    fwp%coo(:) = 2.00
+    fwp%coo(1) = 1.00
+
+    wp_vla(1)%angle = 101.00
+    wp_vla(1)%coo(:) = 10.00
+    wp_vla(1)%coo(2) = 12.00
+
+    wp_vla(2)%angle = 102.00
+    wp_vla(2)%coo(:) = 20.00
+    wp_vla(2)%coo(2) = 22.00
+
+    wp_vla(3)%angle = 103.00
+    wp_vla(3)%coo(:) = 30.00
+    wp_vla(3)%coo(2) = 32.00
+
+    print *, wp, wp_vla, fwp ! After value assignment
+
+end program
diff --git a/gdb/valops.c b/gdb/valops.c
index 3a59512575..1953556bf8 100644
--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -2374,6 +2374,15 @@ value_struct_elt (struct value **argp,
       if (v)
 	return v;
 
+      if (current_language->la_language == language_fortran)
+	{
+	  /* If it is not a field it is the type name of an inherited
+	  structure.  */
+	  v = search_struct_field (name, *argp, t, 1);
+	  if (v)
+	    return v;
+	}
+
       /* C++: If it was not found as a data field, then try to
 	 return it as a pointer to a method.  */
       v = search_struct_method (name, argp, args, 0,
-- 
2.25.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v2 2/2] gdb/fortran: print fortran extended types with ptype

[Nils-Christian Kempke]

Add the print of the base-class of an extended type to the output of
ptype.  This requires the Fortran compiler to emit DW_AT_inheritance
for the extended type.

Co-authored-by: Nils-Christian Kempke <nils-christian.kempke@intel.com>
---
 gdb/f-lang.h                                  | 11 ++++
 gdb/f-typeprint.c                             | 24 ++++++-
 gdb/testsuite/gdb.fortran/oop_extend_type.exp | 65 ++++++++++++++-----
 3 files changed, 81 insertions(+), 19 deletions(-)

diff --git a/gdb/f-lang.h b/gdb/f-lang.h
index 11debd5569..e8463005d7 100644
--- a/gdb/f-lang.h
+++ b/gdb/f-lang.h
@@ -266,6 +266,17 @@ class f_language : public language_defn
 				    int arrayprint_recurse_level,
 				    bool print_rank_only) const;
 
+  /* If TYPE is an extended type, then print out derivation information.
+
+     A typical output could look like this:
+     "Type, extends(point) :: waypoint"
+     "    Type point :: point"
+     "    real(kind=4) :: angle"
+     "End Type waypoint".  */
+
+  void f_type_print_derivation_info (struct type *type,
+				     struct ui_file *stream) const;
+
   /* Print the name of the type (or the ultimate pointer target, function
      value or array element), or the description of a structure or union.
 
diff --git a/gdb/f-typeprint.c b/gdb/f-typeprint.c
index 3b26bf74b6..b68ea79322 100644
--- a/gdb/f-typeprint.c
+++ b/gdb/f-typeprint.c
@@ -284,6 +284,19 @@ f_language::f_type_print_varspec_suffix (struct type *type,
 
 /* See f-lang.h.  */
 
+void
+f_language::f_type_print_derivation_info (struct type *type,
+					  struct ui_file *stream) const
+{
+  const int i = 0;  // Fortran doesn't support multiple inheritance.
+
+  if (TYPE_N_BASECLASSES (type) > 0)
+    fprintf_filtered (stream, ", extends(%s) ::",
+		      TYPE_BASECLASS (type, i)->name ());
+}
+
+/* See f-lang.h.  */
+
 void
 f_language::f_type_print_base (struct type *type, struct ui_file *stream,
 			       int show, int level) const
@@ -396,10 +409,17 @@ f_language::f_type_print_base (struct type *type, struct ui_file *stream,
     case TYPE_CODE_UNION:
     case TYPE_CODE_NAMELIST:
       if (type->code () == TYPE_CODE_UNION)
-	fprintf_filtered (stream, "%*sType, C_Union :: ", level, "");
+	fprintf_filtered (stream, "%*sType, C_Union ::", level, "");
       else
-	fprintf_filtered (stream, "%*sType ", level, "");
+	fprintf_filtered (stream, "%*sType", level, "");
+
+      if (show > 0)
+	f_type_print_derivation_info (type, stream);
+
+      fputs_filtered (" ", stream);
+
       fputs_filtered (type->name (), stream);
+
       /* According to the definition,
 	 we only print structure elements in case show > 0.  */
       if (show > 0)
diff --git a/gdb/testsuite/gdb.fortran/oop_extend_type.exp b/gdb/testsuite/gdb.fortran/oop_extend_type.exp
index 5d73e14a56..3b4e6cac3a 100755
--- a/gdb/testsuite/gdb.fortran/oop_extend_type.exp
+++ b/gdb/testsuite/gdb.fortran/oop_extend_type.exp
@@ -60,12 +60,24 @@ gdb_test "p wp%point" " = \\( coo = \\(1, 2, 1\\) \\)"
 gdb_test "p wp" " = \\( point = \\( coo = \\(1, 2, 1\\) \\), angle = 100 \\)"
 
 gdb_test "whatis wp" "type = Type waypoint"
-gdb_test "ptype wp" \
-  [multi_line "type = Type waypoint" \
-	      "    Type point :: point" \
-	      "    $real :: angle" \
-	      "End Type waypoint"]
-
+set output_pass_wp [multi_line "type = Type, extends\\(point\\) :: waypoint" \
+			       "    Type point :: point" \
+			       "    $real :: angle" \
+			       "End Type waypoint(, allocatable)?"]
+set output_kfail_wp [multi_line "type = Type waypoint" \
+			        "    Type point :: point" \
+			        "    $real :: angle" \
+			        "End Type waypoint(, allocatable)?"]
+
+set test "ptype wp"
+gdb_test_multiple "$test" "$test" {
+    -re "$output_pass_wp\r\n$gdb_prompt $" {
+      pass "$test"
+    }
+    -re "$output_kfail_wp\r\n$gdb_prompt $" {
+      kfail "gcc/49475" "$test"
+    }
+}
 set test "ptype wp%coo"
 gdb_test_multiple "$test" "$test" {
     -re "$real \\(3\\)\r\n$gdb_prompt $" {
@@ -105,11 +117,27 @@ gdb_test_multiple "$test" "$test" {
 }
 
 gdb_test "whatis fwp" "type = Type fancywaypoint"
-gdb_test "ptype fwp" \
-  [multi_line "type = Type fancywaypoint" \
-	      "    Type waypoint :: waypoint" \
-	      "    $logical :: is_fancy" \
-	      "End Type fancywaypoint"]
+set test "ptype fwp"
+
+set output_pass_fwp \
+    [multi_line "type = Type, extends\\(waypoint\\) :: fancywaypoint" \
+		"    Type waypoint :: waypoint" \
+		"    $logical :: is_fancy" \
+		"End Type fancywaypoint"]
+set output_kfail_fwp \
+    [multi_line "type = Type fancywaypoint" \
+		"    Type waypoint :: waypoint" \
+		"    $logical :: is_fancy" \
+		"End Type fancywaypoint"]
+
+gdb_test_multiple "$test" "$test" {
+    -re "$output_pass_fwp\r\n$gdb_prompt $" {
+	pass  "$test"
+    }
+    -re "$output_kfail_fwp\r\n$gdb_prompt $" {
+	kfail "gcc/49475" "$test"
+    }
+}
 
 set test "ptype fwp%coo"
 gdb_test_multiple "$test" "$test" {
@@ -140,12 +168,15 @@ gdb_test "p wp_vla(1)" " = \\( point = \\( coo = \\(10, 12, 10\\) \\), angle = 1
 gdb_test "whatis wp_vla" "type = Type waypoint, allocatable \\(3\\)" \
     "whatis wp_vla after allocation"
 
-gdb_test "ptype wp_vla" \
-  [multi_line "type = Type waypoint" \
-	      "    Type point :: point" \
-	      "    $real :: angle" \
-	      "End Type waypoint, allocatable \\(3\\)"]
-
+set test "ptype wp_vla"
+gdb_test_multiple "$test" "$test" {
+    -re "$output_pass_wp \\(3\\)\r\n$gdb_prompt $" {
+      pass "$test"
+    }
+    -re "$output_kfail_wp \\(3\\)\r\n$gdb_prompt $" {
+      kfail "gcc/49475" "$test"
+    }
+}
 set test "ptype wp_vla(1)%coo"
 gdb_test_multiple "$test" "$test" {
     -re "$real \\(3\\)\r\n$gdb_prompt $" {
-- 
2.25.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

Re: [PATCH v2 1/2] gdb/fortran: add support for accessing fields of extended types

[Tom Tromey]

>>>>> Nils-Christian Kempke via Gdb-patches <gdb-patches@sourceware.org> writes:

> Fortran 2003 supports type extension.  This patch allows access
> to inherited members by using their fully qualified name as described
> in the Fortran standard.

> In doing so the patch also fixes a bug in GDB when trying to access the
> members of a base class in a derived class via the derived class' base
> class member.

> This patch fixes PR22497 and PR26373 on GDB side.

Thank you for the patch.

> +++ b/gdb/testsuite/gdb.fortran/oop_extend_type.exp
> @@ -0,0 +1,159 @@
> +# Copyright 2016 Free Software Foundation, Inc.

You probably should change this to 2022.

This is ok with that change.

Tom

Re: [PATCH v2 2/2] gdb/fortran: print fortran extended types with ptype

[Tom Tromey]

>>>>> Nils-Christian Kempke via Gdb-patches <gdb-patches@sourceware.org> writes:

> Add the print of the base-class of an extended type to the output of
> ptype.  This requires the Fortran compiler to emit DW_AT_inheritance
> for the extended type.

Thanks for the patch.

> +void
> +f_language::f_type_print_derivation_info (struct type *type,
> +					  struct ui_file *stream) const
> +{
> +  const int i = 0;  // Fortran doesn't support multiple inheritance.

gdb doesn't use "//" comments, and normally also doesn't use end-of-line
comments.

> +  if (TYPE_N_BASECLASSES (type) > 0)
> +    fprintf_filtered (stream, ", extends(%s) ::",
> +		      TYPE_BASECLASS (type, i)->name ());

One oddity to be aware of is that any type can actually be passed to the
type printer.  For example you can make a C++ type using multiple
inheritance and then "set lang fortran" and "ptype" that type.

I don't think this code necessarily needs to handle this.  It's sort of
a pathological scenario.

This patch is ok with the "//" thing fixed.

Tom

RE: [PATCH v2 2/2] gdb/fortran: print fortran extended types with ptype

[Kempke, Nils-Christian]

Hi Tom,

Thanks for the feedback! I have incorporated the changes (for patch 1 and 2) and
sent a new v3 here:
https://sourceware.org/pipermail/gdb-patches/2022-April/187486.html
since I do not have write access to GDB.

Cheers,

Nils

> -----Original Message-----
> From: Tom Tromey <tom@tromey.com>
> Sent: Monday, April 4, 2022 5:09 PM
> To: Nils-Christian Kempke via Gdb-patches <gdb-patches@sourceware.org>
> Cc: Kempke, Nils-Christian <nils-christian.kempke@intel.com>;
> tom@tromey.com
> Subject: Re: [PATCH v2 2/2] gdb/fortran: print fortran extended types with
> ptype
> 
> >>>>> Nils-Christian Kempke via Gdb-patches <gdb-
> patches@sourceware.org> writes:
> 
> > Add the print of the base-class of an extended type to the output of
> > ptype.  This requires the Fortran compiler to emit DW_AT_inheritance
> > for the extended type.
> 
> Thanks for the patch.
> 
> > +void
> > +f_language::f_type_print_derivation_info (struct type *type,
> > +					  struct ui_file *stream) const
> > +{
> > +  const int i = 0;  // Fortran doesn't support multiple inheritance.
> 
> gdb doesn't use "//" comments, and normally also doesn't use end-of-line
> comments.
> 
> > +  if (TYPE_N_BASECLASSES (type) > 0)
> > +    fprintf_filtered (stream, ", extends(%s) ::",
> > +		      TYPE_BASECLASS (type, i)->name ());
> 
> One oddity to be aware of is that any type can actually be passed to the
> type printer.  For example you can make a C++ type using multiple
> inheritance and then "set lang fortran" and "ptype" that type.
> 
> I don't think this code necessarily needs to handle this.  It's sort of
> a pathological scenario.
> 
> This patch is ok with the "//" thing fixed.
> 
> Tom
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928