From bfca584fae65570fa8ed052f662948763f3ccfa8 Mon Sep 17 00:00:00 2001 From: Pierre-Marie de Rodat Date: Tue, 15 Sep 2015 11:56:03 +0200 Subject: [PATCH] [Ada] Enhance type printing for arrays with variable-sized elements This change is relevant only for standard DWARF (as opposed to the GNAT encodings extensions): at the time of writing it only makes a difference with GCC patches that are to be integrated: see the patch series submission at . Given the following Ada declarations: subtype Small_Int is Natural range 0 .. 100; type R_Type (L : Small_Int := 0) is record S : String (1 .. L); end record; type A_Type is array (Natural range <>) of R_Type; A : A_Type := (1 => (L => 0, S => ""), 2 => (L => 2, S => "ab")); Before this change, we would get the following GDB session: (gdb) ptype a type = array (1 .. 2) of foo.r_type This is wrong: "a" is not a packed array. This output comes from the fact that, because R_Type has a dynamic size (with a maximum), the compiler has to describe in the debugging information the size allocated for each array element (i.e. the stride, in DWARF parlance: see DW_AT_byte_stride). Ada type printing currently assumes that arrays with a stride are packed, hence the above output. In practice, GNAT never performs bit-packing for arrays that contain variable-sized elements. Leveraging this fact, this patch enhances type printing so that ptype does not pretend that arrays are packed when they have a stride and they contain dynamic elements. After this change, we get the following expected output: (gdb) ptype a type = array (1 .. 2) of foo.r_type gdb/ChangeLog: * ada-typeprint.c (print_array_type): Do not describe arrays as packed when they embed dynamic elements. gdb/testsuite/ChangeLog: * gdb.ada/array_of_variable_length.exp: New testcase. * gdb.ada/array_of_variable_length/foo.adb: New file. * gdb.ada/array_of_variable_length/pck.adb: New file. * gdb.ada/array_of_variable_length/pck.ads: New file. Tested on x86_64-linux, no regression. --- gdb/ChangeLog | 5 +++ gdb/ada-typeprint.c | 11 ++++-- gdb/testsuite/ChangeLog | 7 ++++ gdb/testsuite/gdb.ada/array_of_variable_length.exp | 44 ++++++++++++++++++++++ .../gdb.ada/array_of_variable_length/foo.adb | 21 +++++++++++ .../gdb.ada/array_of_variable_length/pck.adb | 23 +++++++++++ .../gdb.ada/array_of_variable_length/pck.ads | 32 ++++++++++++++++ 7 files changed, 140 insertions(+), 3 deletions(-) create mode 100644 gdb/testsuite/gdb.ada/array_of_variable_length.exp create mode 100644 gdb/testsuite/gdb.ada/array_of_variable_length/foo.adb create mode 100644 gdb/testsuite/gdb.ada/array_of_variable_length/pck.adb create mode 100644 gdb/testsuite/gdb.ada/array_of_variable_length/pck.ads diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 1e62667..81ba17a 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2015-09-15 Pierre-Marie de Rodat + + * ada-typeprint.c (print_array_type): Do not describe arrays as + packed when they embed dynamic elements. + 2015-09-15 Philippe Waroquiers * symtab.h (address_class): Document that TLS variables diff --git a/gdb/ada-typeprint.c b/gdb/ada-typeprint.c index fd85138..1fb0f0e 100644 --- a/gdb/ada-typeprint.c +++ b/gdb/ada-typeprint.c @@ -386,6 +386,7 @@ print_array_type (struct type *type, struct ui_file *stream, int show, { int bitsize; int n_indices; + struct type *elt_type = NULL; if (ada_is_constrained_packed_array_type (type)) type = ada_coerce_to_simple_array_type (type); @@ -448,11 +449,15 @@ print_array_type (struct type *type, struct ui_file *stream, int show, fprintf_filtered (stream, "%s<>", i == i0 ? "" : ", "); } + elt_type = ada_array_element_type (type, n_indices); fprintf_filtered (stream, ") of "); wrap_here (""); - ada_print_type (ada_array_element_type (type, n_indices), "", stream, - show == 0 ? 0 : show - 1, level + 1, flags); - if (bitsize > 0) + ada_print_type (elt_type, "", stream, show == 0 ? 0 : show - 1, level + 1, + flags); + /* Arrays with variable-length elements are never bit-packed in practice but + compilers have to describe their stride so that we can properly fetch + individual elements. Do not say the array is packed in this case. */ + if (bitsize > 0 && !is_dynamic_type (elt_type)) fprintf_filtered (stream, " ", bitsize); } diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 43440c2..3de56d3 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,10 @@ +2015-09-15 Pierre-Marie de Rodat + + * gdb.ada/array_of_variable_length.exp: New testcase. + * gdb.ada/array_of_variable_length/foo.adb: New file. + * gdb.ada/array_of_variable_length/pck.adb: New file. + * gdb.ada/array_of_variable_length/pck.ads: New file. + 2015-09-15 Doug Evans * gdb.base/callfuncs.exp (do_function_calls): Handle clang naming diff --git a/gdb/testsuite/gdb.ada/array_of_variable_length.exp b/gdb/testsuite/gdb.ada/array_of_variable_length.exp new file mode 100644 index 0000000..7a7b2f0 --- /dev/null +++ b/gdb/testsuite/gdb.ada/array_of_variable_length.exp @@ -0,0 +1,44 @@ +# Copyright 2015 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 . + +load_lib "ada.exp" + +standard_ada_testfile foo + +if {[gdb_compile_ada "${srcfile}" "${binfile}" executable [list debug]] != "" } { + return -1 +} + +clean_restart ${testfile} + +set bp_location [gdb_get_line_number "BREAK" ${testdir}/foo.adb] +runto "foo.adb:$bp_location" + +# Pck.A is an array that embeds elements with variable size so compilers will +# emit DWARF attributes such as DW_AT_byte_stride to tell GDB how to fetch +# individual elements. Array stride is also a way to describe packed arrays: +# make sure we do not consider Pck.A as a packed array. +gdb_test "ptype pck.a" "array \\(1 \\.\\. 2\\) of pck\\.r_type" + +# Make sure this also works with a type from a fully evaluated value. During +# evaluation, dynamic types can be "resolved" so GDB internals could "forget" +# that elements have variable size. Fortunately, type resolution of array +# elements happens only when processing individual elements (i.e. the resolved +# array type is still associated to the dynamic element type), so the following +# is supposed to work. +gdb_test "print pck.a" \ + "= \\(\\(l => 0, s => \"\"\\), \\(l => 2, s => \"ab\"\\)\\)" +gdb_test "ptype $"\ + "array \\(1 \\.\\. 2\\) of pck\\.r_type" diff --git a/gdb/testsuite/gdb.ada/array_of_variable_length/foo.adb b/gdb/testsuite/gdb.ada/array_of_variable_length/foo.adb new file mode 100644 index 0000000..b8846cf --- /dev/null +++ b/gdb/testsuite/gdb.ada/array_of_variable_length/foo.adb @@ -0,0 +1,21 @@ +-- Copyright 2015 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 . + +with Pck; use Pck; + +procedure Foo is +begin + Do_Nothing (A); -- BREAK +end Foo; diff --git a/gdb/testsuite/gdb.ada/array_of_variable_length/pck.adb b/gdb/testsuite/gdb.ada/array_of_variable_length/pck.adb new file mode 100644 index 0000000..a6ffddc --- /dev/null +++ b/gdb/testsuite/gdb.ada/array_of_variable_length/pck.adb @@ -0,0 +1,23 @@ +-- Copyright 2015 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 . + +package body Pck is + + procedure Do_Nothing (A : A_Type) is + begin + null; + end Do_Nothing; + +end Pck; diff --git a/gdb/testsuite/gdb.ada/array_of_variable_length/pck.ads b/gdb/testsuite/gdb.ada/array_of_variable_length/pck.ads new file mode 100644 index 0000000..ce2a21e --- /dev/null +++ b/gdb/testsuite/gdb.ada/array_of_variable_length/pck.ads @@ -0,0 +1,32 @@ +-- Copyright 2015 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 . + +package Pck is + + subtype Small_Int is Natural range 0 .. 100; + + type R_Type (L : Small_Int := 0) is record + S : String (1 .. L); + end record; + + type A_Type is array (Natural range <>) of R_Type; + + A : A_Type := + (1 => (L => 0, S => ""), + 2 => (L => 2, S => "ab")); + + procedure Do_Nothing (A : A_Type); + +end Pck; -- 2.7.4