old-cross-binutils/gdb/testsuite/gdb.dwarf2/implptrpiece.exp

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# Copyright 2013-2016 Free Software Foundation, Inc.
Fix PR symtab/15391 PR symtab/15391 is a failure with the DW_OP_GNU_implicit_pointer feature. I tracked it down to a logic error in read_pieced_value. The code truncates this_size_bits according to the type size and offset too early -- it should do it after taking bits_to_skip into account. This patch fixes the bug. While testing this, I also tripped across a latent bug because indirect_pieced_value does not sign-extend where needed. This patch fixes this bug as well. Finally, Pedro pointed out that a previous version implemented sign extension incorrectly. This version introduces a new gdb_sign_extend function for this. A couple of notes on this function: * It has the gdb_ prefix to avoid clashes with various libraries that felt free to avoid proper namespacing. There is a "sign_extend" function in a Tile GX header, in an SOM-related BFD header (and in sh64-tdep.c and as a macro in arm-wince-tdep.c, but those are ours...) * I looked at all the sign extensions in gdb and didn't see ones that I felt comfortable converting to use this function; in large part because I don't have a good way to test the conversion. Built and regtested on x86-64 Fedora 18. New test cases included; this required a minor addition to the DWARF assembler. Note that the DWARF CU made by implptrpiece.exp uses a funny pointer size in order to show the sign-extension bug on all platforms. * dwarf2loc.c (read_pieced_value): Truncate this_size_bits after taking bits_to_skip into account. Sign extend byte_offset. * utils.h (gdb_sign_extend): Declare. * utils.c (gdb_sign_extend): New function. * gdb.dwarf2/implptrpiece.exp: New file. * gdb.dwarf2/implptrconst.exp (d): New variable. Print d. * lib/dwarf2.exp (Dwarf::_location): Handle DW_OP_piece.
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# 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/>.
load_lib dwarf.exp
# This test can only be run on targets which support DWARF-2 and use gas.
if {![dwarf2_support]} {
return 0
}
if { [skip_cplus_tests] } { continue }
standard_testfile main.c implptrpiece-dw.S
# Make some DWARF for the test.
set asm_file [standard_output_file $srcfile2]
Dwarf::assemble $asm_file {
# Using a funny address size here and in the pointer type lets us
# also check for a sign-extension bug in the
# DW_OP_GNU_implicit_pointer code.
cu { addr_size 2 } {
compile_unit {} {
declare_labels struct_label short_type_label
declare_labels char_type_label ptr_label
declare_labels var_label
struct_label: structure_type {
{name S}
{byte_size 4 DW_FORM_sdata}
} {
member {
{name a}
{type :$short_type_label}
{data_member_location 0 DW_FORM_sdata}
}
member {
{name b}
{type :$char_type_label}
{data_member_location 2 DW_FORM_sdata}
}
member {
{name c}
{type :$char_type_label}
{data_member_location 3 DW_FORM_sdata}
}
}
short_type_label: base_type {
{name "short int"}
{encoding @DW_ATE_signed}
{byte_size 2 DW_FORM_sdata}
}
char_type_label: base_type {
{name "signed char"}
{encoding @DW_ATE_signed}
{byte_size 1 DW_FORM_sdata}
}
# See comment above to understand the pointer size.
ptr_label: pointer_type {
{byte_size 2 DW_FORM_sdata}
{type :$char_type_label}
}
var_label: DW_TAG_variable {
{name s}
{type :$struct_label}
{location {
const1u 1
stack_value
piece 2
const1u 2
stack_value
piece 1
const1u 3
stack_value
piece 1
} SPECIAL_expr}
}
DW_TAG_variable {
{name p}
{type :$ptr_label}
{location {
GNU_implicit_pointer $var_label 2
} SPECIAL_expr}
}
}
}
}
if { [build_executable ${testfile}.exp ${testfile} \
[list $srcfile $asm_file] {nodebug}] } {
Fix PR symtab/15391 PR symtab/15391 is a failure with the DW_OP_GNU_implicit_pointer feature. I tracked it down to a logic error in read_pieced_value. The code truncates this_size_bits according to the type size and offset too early -- it should do it after taking bits_to_skip into account. This patch fixes the bug. While testing this, I also tripped across a latent bug because indirect_pieced_value does not sign-extend where needed. This patch fixes this bug as well. Finally, Pedro pointed out that a previous version implemented sign extension incorrectly. This version introduces a new gdb_sign_extend function for this. A couple of notes on this function: * It has the gdb_ prefix to avoid clashes with various libraries that felt free to avoid proper namespacing. There is a "sign_extend" function in a Tile GX header, in an SOM-related BFD header (and in sh64-tdep.c and as a macro in arm-wince-tdep.c, but those are ours...) * I looked at all the sign extensions in gdb and didn't see ones that I felt comfortable converting to use this function; in large part because I don't have a good way to test the conversion. Built and regtested on x86-64 Fedora 18. New test cases included; this required a minor addition to the DWARF assembler. Note that the DWARF CU made by implptrpiece.exp uses a funny pointer size in order to show the sign-extension bug on all platforms. * dwarf2loc.c (read_pieced_value): Truncate this_size_bits after taking bits_to_skip into account. Sign extend byte_offset. * utils.h (gdb_sign_extend): Declare. * utils.c (gdb_sign_extend): New function. * gdb.dwarf2/implptrpiece.exp: New file. * gdb.dwarf2/implptrconst.exp (d): New variable. Print d. * lib/dwarf2.exp (Dwarf::_location): Handle DW_OP_piece.
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return -1
}
# We need --readnow because otherwise we never read in the CU we
# created above.
set saved_gdbflags $GDBFLAGS
set GDBFLAGS "$GDBFLAGS -readnow"
clean_restart ${testfile}
set GDBFLAGS $saved_gdbflags
if ![runto_main] {
return -1
}
gdb_test "print/d p\[-1\]" " = 0"