old-cross-binutils/gdb/testsuite/gdb.dwarf2/implptrconst.exp
Tom Tromey 5bd1ef568c 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.
2013-06-18 18:11:19 +00:00

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# Copyright 2013 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/>.
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 .c implptrconst-dw.S
# Make some DWARF for the test.
set asm_file [standard_output_file $srcfile2]
Dwarf::assemble $asm_file {
# Creating a CU with 4-byte addresses lets this test link on both
# 32- and 64-bit machines.
cu { addr_size 4 } {
compile_unit {} {
declare_labels byte_label size_type_label array_label
declare_labels var_label ptr_label
byte_label: base_type {
{name byte}
{encoding @DW_ATE_signed}
{byte_size 1 DW_FORM_sdata}
}
size_type_label: base_type {
{name sizetype}
{encoding @DW_ATE_unsigned}
{byte_size 4 DW_FORM_sdata}
}
array_label: array_type {
{type :$byte_label}
} {
subrange_type {
{type :$size_type_label}
{upper_bound 7 DW_FORM_data1}
}
}
var_label: DW_TAG_variable {
{name b}
{type :$array_label}
{const_value rstuvwxy DW_FORM_block1}
}
ptr_label: pointer_type {
{byte_size 4 DW_FORM_sdata}
{type :$byte_label}
}
DW_TAG_variable {
{name c}
{type :$ptr_label}
{location {
GNU_implicit_pointer $var_label 0
} SPECIAL_expr}
}
DW_TAG_variable {
{name d}
{type :$ptr_label}
{location {
GNU_implicit_pointer $var_label 2
} SPECIAL_expr}
}
}
}
}
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
}
# 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 *c" " = 114 'r'"
gdb_test "print d\[-2\]" " = 114 'r'"