From dc53a7adb516adbf2f646a078a1140b1044a39f5 Mon Sep 17 00:00:00 2001 From: Joel Brobecker Date: Wed, 29 Jan 2014 17:39:56 +0400 Subject: [PATCH] DWARF: Add array DW_AT_bit_stride and DW_AT_byte_stride support Consider the following declarations in Ada... type Item is range -32 .. 31; for Item'Size use 6; type Table is array (Natural range 0 .. 4) of Item; pragma Pack (Table); ... which declare a packed array whose elements are 6 bits long. The debugger currently does not notice that the array is packed, and thus prints values of this type incorrectly. This can be seen in the "ptype" output: (gdb) ptype table type = array (0 .. 4) of foo.item Normally, the debugger should print: (gdb) ptype table type = array (0 .. 4) of foo.item The debugging information for this array looks like this: .uleb128 0xf # (DIE (0x15c) DW_TAG_array_type) .long .LASF9 # DW_AT_name: "pck__table" .byte 0x6 # DW_AT_bit_stride .long 0x1a9 # DW_AT_type .uleb128 0x10 # (DIE (0x16a) DW_TAG_subrange_type) .long 0x3b # DW_AT_type .byte 0 # DW_AT_lower_bound .byte 0x4 # DW_AT_upper_bound .byte 0 # end of children of DIE 0x15c The interesting part is the DW_AT_bit_stride attribute, which tells the size of the array elements is 6 bits, rather than the normal element type's size. This patch adds support for this attribute by first creating gdbtypes.c::create_array_type_with_stride, which is an enhanced version of create_array_type taking an extra parameter as the stride. The old create_array_type can then be re-implemented very simply by calling the new create_array_type_with_stride. We can then use this new function from dwarf2read, to create arrays with or without stride. gdb/ChangeLog: * gdbtypes.h (create_array_type_with_stride): Add declaration. * gdbtypes.c (create_array_type_with_stride): New function, renaming create_array_type, but with an added parameter called "bit_stride". (create_array_type): Re-implement using create_array_type_with_stride. * dwarf2read.c (read_array_type): Add support for DW_AT_byte_stride and DW_AT_bit_stride attributes. gdb/testsuite/ChangeLog: * gdb.dwarf2/arr-stride.c: New file. * gdb.dwarf2/arr-stride.exp: New file. The test, relying purely on generating an assembly file, only verifies the type description of our array. But I was also able to verify manually that the debugger print values of these types correctly as well (which was not the case prior to this patch). --- gdb/ChangeLog | 11 +++ gdb/dwarf2read.c | 18 +++- gdb/gdbtypes.c | 27 +++++- gdb/gdbtypes.h | 4 + gdb/testsuite/ChangeLog | 5 ++ gdb/testsuite/gdb.dwarf2/arr-stride.c | 20 +++++ gdb/testsuite/gdb.dwarf2/arr-stride.exp | 108 ++++++++++++++++++++++++ 7 files changed, 187 insertions(+), 6 deletions(-) create mode 100644 gdb/testsuite/gdb.dwarf2/arr-stride.c create mode 100644 gdb/testsuite/gdb.dwarf2/arr-stride.exp diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 3a02a49057..a4377a9e69 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,14 @@ +2014-02-26 Joel Brobecker + + * gdbtypes.h (create_array_type_with_stride): Add declaration. + * gdbtypes.c (create_array_type_with_stride): New function, + renaming create_array_type, but with an added parameter + called "bit_stride". + (create_array_type): Re-implement using + create_array_type_with_stride. + * dwarf2read.c (read_array_type): Add support for DW_AT_byte_stride + and DW_AT_bit_stride attributes. + 2014-02-26 Pedro Alves * breakpoint.c (bpstat_check_breakpoint_conditions): Handle diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c index 3eaa0b1823..d7dc38cdec 100644 --- a/gdb/dwarf2read.c +++ b/gdb/dwarf2read.c @@ -13281,6 +13281,7 @@ read_array_type (struct die_info *die, struct dwarf2_cu *cu) int ndim = 0; struct cleanup *back_to; const char *name; + unsigned int bit_stride = 0; element_type = die_type (die, cu); @@ -13289,13 +13290,22 @@ read_array_type (struct die_info *die, struct dwarf2_cu *cu) if (type) return type; + attr = dwarf2_attr (die, DW_AT_byte_stride, cu); + if (attr != NULL) + bit_stride = DW_UNSND (attr) * 8; + + attr = dwarf2_attr (die, DW_AT_bit_stride, cu); + if (attr != NULL) + bit_stride = DW_UNSND (attr); + /* Irix 6.2 native cc creates array types without children for arrays with unspecified length. */ if (die->child == NULL) { index_type = objfile_type (objfile)->builtin_int; range_type = create_range_type (NULL, index_type, 0, -1); - type = create_array_type (NULL, element_type, range_type); + type = create_array_type_with_stride (NULL, element_type, range_type, + bit_stride); return set_die_type (die, type, cu); } @@ -13335,12 +13345,14 @@ read_array_type (struct die_info *die, struct dwarf2_cu *cu) int i = 0; while (i < ndim) - type = create_array_type (NULL, type, range_types[i++]); + type = create_array_type_with_stride (NULL, type, range_types[i++], + bit_stride); } else { while (ndim-- > 0) - type = create_array_type (NULL, type, range_types[ndim]); + type = create_array_type_with_stride (NULL, type, range_types[ndim], + bit_stride); } /* Understand Dwarf2 support for vector types (like they occur on diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c index 622eff08bc..98cb873ee8 100644 --- a/gdb/gdbtypes.c +++ b/gdb/gdbtypes.c @@ -951,14 +951,18 @@ get_array_bounds (struct type *type, LONGEST *low_bound, LONGEST *high_bound) Elements will be of type ELEMENT_TYPE, the indices will be of type RANGE_TYPE. + If BIT_STRIDE is not zero, build a packed array type whose element + size is BIT_STRIDE. Otherwise, ignore this parameter. + FIXME: Maybe we should check the TYPE_CODE of RESULT_TYPE to make sure it is TYPE_CODE_UNDEF before we bash it into an array type? */ struct type * -create_array_type (struct type *result_type, - struct type *element_type, - struct type *range_type) +create_array_type_with_stride (struct type *result_type, + struct type *element_type, + struct type *range_type, + unsigned int bit_stride) { LONGEST low_bound, high_bound; @@ -975,6 +979,9 @@ create_array_type (struct type *result_type, In such cases, the array length should be zero. */ if (high_bound < low_bound) TYPE_LENGTH (result_type) = 0; + else if (bit_stride > 0) + TYPE_LENGTH (result_type) = + (bit_stride * (high_bound - low_bound + 1) + 7) / 8; else TYPE_LENGTH (result_type) = TYPE_LENGTH (element_type) * (high_bound - low_bound + 1); @@ -983,6 +990,8 @@ create_array_type (struct type *result_type, (struct field *) TYPE_ZALLOC (result_type, sizeof (struct field)); TYPE_INDEX_TYPE (result_type) = range_type; TYPE_VPTR_FIELDNO (result_type) = -1; + if (bit_stride > 0) + TYPE_FIELD_BITSIZE (result_type, 0) = bit_stride; /* TYPE_FLAG_TARGET_STUB will take care of zero length arrays. */ if (TYPE_LENGTH (result_type) == 0) @@ -991,6 +1000,18 @@ create_array_type (struct type *result_type, return result_type; } +/* Same as create_array_type_with_stride but with no bit_stride + (BIT_STRIDE = 0), thus building an unpacked array. */ + +struct type * +create_array_type (struct type *result_type, + struct type *element_type, + struct type *range_type) +{ + return create_array_type_with_stride (result_type, element_type, + range_type, 0); +} + struct type * lookup_array_range_type (struct type *element_type, LONGEST low_bound, LONGEST high_bound) diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h index 643c61006b..080c3eb84e 100644 --- a/gdb/gdbtypes.h +++ b/gdb/gdbtypes.h @@ -1529,8 +1529,12 @@ extern struct type *lookup_function_type_with_arguments (struct type *, extern struct type *create_range_type (struct type *, struct type *, LONGEST, LONGEST); +extern struct type *create_array_type_with_stride + (struct type *, struct type *, struct type *, unsigned int); + extern struct type *create_array_type (struct type *, struct type *, struct type *); + extern struct type *lookup_array_range_type (struct type *, LONGEST, LONGEST); extern struct type *create_string_type (struct type *, struct type *, diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 09cc8a3228..476e1a34e0 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2014-02-26 Joel Brobecker + + * gdb.dwarf2/arr-stride.c: New file. + * gdb.dwarf2/arr-stride.exp: New file. + 2014-02-26 Pedro Alves * gdb.ada/tasks.exp: Set a task-specific breakpoint at break_me diff --git a/gdb/testsuite/gdb.dwarf2/arr-stride.c b/gdb/testsuite/gdb.dwarf2/arr-stride.c new file mode 100644 index 0000000000..978ef8d305 --- /dev/null +++ b/gdb/testsuite/gdb.dwarf2/arr-stride.c @@ -0,0 +1,20 @@ +/* Copyright 2014 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 . */ + +int +main (void) +{ + return 0; +} diff --git a/gdb/testsuite/gdb.dwarf2/arr-stride.exp b/gdb/testsuite/gdb.dwarf2/arr-stride.exp new file mode 100644 index 0000000000..f2a1f39d82 --- /dev/null +++ b/gdb/testsuite/gdb.dwarf2/arr-stride.exp @@ -0,0 +1,108 @@ +# Copyright 2014 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 dwarf.exp + +# This test can only be run on targets which support DWARF-2 and use gas. +if {![dwarf2_support]} { + return 0 +} + +standard_testfile arr-stride.c arr-stride-dw.S + +# Make some DWARF for the test. +set asm_file [standard_output_file $srcfile2] +Dwarf::assemble $asm_file { + cu {} { + DW_TAG_compile_unit { + {DW_AT_language @DW_LANG_Ada95} + {DW_AT_name foo.adb} + {DW_AT_comp_dir /tmp} + } { + declare_labels integer_label array_elt_label array_label \ + big_array_label + + integer_label: DW_TAG_base_type { + {DW_AT_byte_size 4 DW_FORM_sdata} + {DW_AT_encoding @DW_ATE_signed} + {DW_AT_name integer} + } + + array_elt_label: DW_TAG_subrange_type { + {DW_AT_lower_bound 0xe0 DW_FORM_data1} + {DW_AT_upper_bound 0x1f DW_FORM_data1} + {DW_AT_name pck__item} + {DW_AT_type :$integer_label} + } + + DW_TAG_typedef { + {DW_AT_name pck__table} + {DW_AT_type :$array_label} + } + + array_label: DW_TAG_array_type { + {DW_AT_name pck__table} + {DW_AT_bit_stride 6 DW_FORM_data1} + {DW_AT_type :$array_elt_label} + } { + DW_TAG_subrange_type { + {DW_AT_type :$integer_label} + {DW_AT_lower_bound 0 DW_FORM_data1} + {DW_AT_upper_bound 4 DW_FORM_data1} + } + } + + DW_TAG_typedef { + {DW_AT_name pck__big_table} + {DW_AT_type :$big_array_label} + } + + big_array_label: DW_TAG_array_type { + {DW_AT_name pck__big_table} + {DW_AT_byte_stride 1 DW_FORM_data1} + {DW_AT_type :$array_elt_label} + } { + DW_TAG_subrange_type { + {DW_AT_type :$integer_label} + {DW_AT_lower_bound 0 DW_FORM_data1} + {DW_AT_upper_bound 4 DW_FORM_data1} + } + } + } + } +} + +if {[gdb_compile ${srcdir}/${subdir}/${srcfile} ${binfile}1.o \ + object {nodebug}] != ""} { + return -1 +} + +if {[gdb_compile $asm_file ${binfile}2.o object {nodebug}] != ""} { + return -1 +} + +if {[gdb_compile [list ${binfile}1.o ${binfile}2.o] \ + "${binfile}" executable {}] != ""} { + return -1 +} + +clean_restart ${testfile} + +gdb_test_no_output "set language ada" + +gdb_test "ptype pck.table" \ + "type = array \\(0 \\.\\. 4\\) of pck\\.item " + +gdb_test "ptype pck.big_table" \ + "type = array \\(0 \\.\\. 4\\) of pck\\.item " -- 2.34.1