Recently I fixed a bug that caused a DW_OP_implicit_pointer with non-zero
offset into a DW_OP_implicit_value to be handled incorrectly on big-endian
targets. GDB ignored the offset and copied the wrong bytes:
https://sourceware.org/ml/gdb-patches/2017-01/msg00251.html
But there is still a similar issue when a DW_OP_implicit_pointer points
into a DW_OP_stack_value instead; and again, the offset is ignored. There
is an important difference, though: While implicit values are treated like
blocks of data and anchored at the lowest-addressed byte, stack values
traditionally contain integer numbers and are anchored at the *least
significant* byte. Also, stack values do not come in varying sizes, but
are cut down appropriately when used. Thus, on big-endian targets the
scenario looks like this (higher addresses shown right):
|<- - - - - Stack value - - - - - - ->|
| |
|<- original object ->|
|
| offset ->|####|
^^^^
de-referenced
implicit pointer
(Note how the original object's size influences the position of the
de-referenced implicit pointer within the stack value. This is not the
case for little-endian targets, where the original object starts at offset
zero within the stack value.)
This patch implements the logic indicated in the above diagram and adds an
appropriate test case. A new function dwarf2_fetch_die_type_sect_off is
added; it is used for retrieving the original object's type, so its size
can be determined. That type is passed to dwarf2_evaluate_loc_desc_full
via a new parameter.
gdb/ChangeLog:
* dwarf2loc.c (indirect_synthetic_pointer): Get data type of
pointed-to DIE and pass it to dwarf2_evaluate_loc_desc_full.
(dwarf2_evaluate_loc_desc_full): New parameter subobj_type; rename
byte_offset to subobj_byte_offset. Fix the handling of
DWARF_VALUE_STACK on big-endian targets when coming via an
implicit pointer.
(dwarf2_evaluate_loc_desc): Adjust call to
dwarf2_evaluate_loc_desc_full.
* dwarf2loc.h (dwarf2_fetch_die_type_sect_off): New declaration.
* dwarf2read.c (dwarf2_fetch_die_type_sect_off): New function.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp: Add support for DW_OP_implicit_pointer.
* gdb.dwarf2/nonvar-access.exp: Add test for stack value location
and implicit pointer into such a location.
DWARF-5 has new form DW_FORM_data16. The problem is that GDB cannot pass
16-byte constant as a constant value as that would require GDB to use GCC
extension __int128.
Formerly such data was coded as DW_FORM_block* so GDB still decodes
DW_FORM_data16 like DW_FORM_block*.
gdb/ChangeLog
2017-02-20 Jan Kratochvil <jan.kratochvil@redhat.com>
* dwarf2read.c (skip_one_die, read_attribute_value)
(dwarf2_const_value_attr, dump_die_shallow)
(dwarf2_get_attr_constant_value, dwarf2_fetch_constant_bytes)
(skip_form_bytes, attr_form_is_constant): Handle DW_FORM_data16.
gdb/testsuite/ChangeLog
2017-02-20 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.dwarf2/formdata16.c: New file.
* gdb.dwarf2/formdata16.exp: New file.
* lib/dwarf.exp (Dwarf): Add DW_FORM_data16.
The test case implptrpiece.exp accesses the second byte of the short
integer number 1 and expects it to be zero. This is valid for
little-endian targets, but fails on big-endian targets.
This is fixed by distinguishing the expected value by endianness.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/implptrpiece.exp: Fix check for big-endian targets.
When a variable's location is expressed as DW_OP_implicit_value, but the
given value is longer than needed, which bytes should be used? GDB's
current logic was introduced with a patch from 2011 and uses the "least
significant" bytes:
https://sourceware.org/ml/gdb-patches/2011-08/msg00123.html
Now consider a sub-value from such a location at a given offset, accessed
through DW_OP_implicit_pointer. Which bytes should be used for that? The
patch above *always* uses the last bytes on big-endian targets, ignoring
the offset.
E.g., given the code snippet
const char foo[] = "Hello, world!";
const char *a = &foo[0];
const char *b = &foo[7];
assume that `foo' is described as DW_OP_implicit_value and `a' and `b'
each as DW_OP_implicit_pointer into that value. Then with current GDB
`*a' and `*b' yield the same result -- the string's zero terminator.
This patch basically reverts the portion of the patch above that deals
with DW_OP_implicit_value. This fixes the offset handling and also goes
back to dropping the last instead of the first bytes on big-endian targets
if the implicit value is longer than needed. The latter aspect of the
change probably doesn't matter for actual programs, but simplifies the
logic.
The patch also cleans up the original code a bit and adds appropriate test
cases.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/dw2-op-stack-value.exp: Adjust expected result of
taking a 2-byte value out of a 4-byte DWARF implicit value on
big-endian targets.
* gdb.dwarf2/nonvar-access.exp: Add more comments to existing
logic. Add test cases for DW_OP_implicit.
gdb/ChangeLog:
* dwarf2loc.c (dwarf2_evaluate_loc_desc_full): For
DWARF_VALUE_LITERAL, no longer ignore the offset on big-endian
targets. And if the implicit value is longer than needed, extract
the first bytes instead of the "least significant" ones.
This patch adds a DW_OP_implicit_value in dwarf assembler, and uses
dwarf assembler in implptr-64bit.exp. Using dwarf assembler in
implptr-64bit.exp exposes some limitations in dwarf assembler,
- some variables are not evaluated in the caller's context, so we
can not pass variable to assembler, like this
Dwarf::assemble $asm_file {
cu {
version $dwarf_version
addr_size $addr_size
is_64 $is_64
} {
}
and
{DW_AT_type :$struct_label "DW_FORM_ref$ref_addr_size"}
this limitation is fixed by adding "uplevel" and "subst".
- dwarf assembler doesn't emit DW_FORM_ref_addr for label referencing.
this limitation is fixed by adding a new character "%",
{ type %$int_label }
this means we want to emit DW_FORM_ref_addr for label referencing.
- we can't set the form of label referencing offset in dwarf assembler.
Nowadays, dwarf assembler guesses the form of labels, which is
DW_FORM_ref4. However, in implptr-64bit.exp, both DW_FORM_ref4
and DW_FORM_ref8 is used (see REF_ADDR in implptr-64bit.S). This
patch adds the flexibility of setting the form of label reference.
Both of them below are valid,
{DW_AT_type :$struct_label}
{DW_AT_type :$struct_label DW_FORM_ref8}
the former form is the default DW_FORM_ref4.
I compared the .debug_info of objects without and with this patch
applied. There is no changes except abbrev numbers.
gdb/testsuite:
2017-01-25 Andreas Arnez <arnez@linux.vnet.ibm.com>
Yao Qi <yao.qi@linaro.org>
* gdb.dwarf2/implptr-64bit.exp: Use dwarf assembler.
* gdb.dwarf2/implptr-64bit.S: Remove.
* lib/dwarf.exp (Dwarf): Handle character "%". Evaluate some
variables in caller's context. Add DW_OP_implicit_value.
This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.
gdb/ChangeLog:
Update copyright year range in all GDB files.
This patch adds support for DW_AT_main_subprogram.
This is PR symtab/16264.
DW_AT_main_subprogram is used to mark a program's entry point. GCC
can emit this, and I hope to change the Rust compiler to emit it as
well.
GDB already supports an older, pre-DWARF 4 convention adopted by
FORTRAN compilers, namely to emit DW_AT_calling_convention for the
"main" function. However, I think this support in GDB had a small
bug, in that it seems to rely on the DW_AT_name being read before
DW_AT_calling_convention. This patch fixes this as well.
Built and regtested on x86-64 Fedora 24 and the buildbot. New test
case included.
2016-12-02 Tom Tromey <tom@tromey.com>
PR symtab/16264:
* dwarf2read.c (struct partial_die_info) <main_subprogram>: New
member.
(add_partial_symbol): Call set_objfile_main_name.
(read_partial_die): Handle DW_AT_main_subprogram.
<DW_AT_calling_convention>: don't call set_objfile_main_name, but
set main_subprogram flag.
2016-12-02 Tom Tromey <tom@tromey.com>
* gdb.dwarf2/main-subprogram.c: New file.
* gdb.dwarf2/main-subprogram.exp: New file.
When the user writes or reads a variable whose location is described
with DWARF pieces (DW_OP_piece or DW_OP_bit_piece), GDB's helper
function copy_bitwise is invoked for each piece. The implementation of
this function has a bug that may result in a corrupted copy, depending
on alignment and bit size. (Full-byte copies are not affected.)
This rewrites copy_bitwise, replacing its algorithm by a fixed version,
and adding an appropriate test case. Without the fix the new test case
fails, e.g.:
print def_t
$2 = {a = 0, b = 4177919}
(gdb) FAIL: gdb.dwarf2/nonvar-access.exp: print def_t
Written in binary, the wrong result above looks like this:
01111111011111111111111
Which means that two zero bits have sneaked into the copy of the
original all-one bit pattern. The test uses this simple all-one value
in order to avoid another GDB bug that causes the DWARF piece of a
DW_OP_stack_value to be taken from the wrong end on big-endian
architectures.
gdb/ChangeLog:
* dwarf2loc.c (extract_bits_primitive): Remove.
(extract_bits): Remove.
(copy_bitwise): Rewrite. Fixes a possible corruption that may
occur for non-byte-aligned copies.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/nonvar-access.exp: Add a test for accessing
non-byte-aligned bit fields.
The DW_AT_data_bit_offset attribute was introduced by DWARF V4 and
allows specifying the offset of a data member within its containing
entity. But although the new attribute was intended to replace
DW_AT_bit_offset for this purpose, GDB ignores it, and thus GCC still
emits DW_AT_bit_offset instead. See also
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71669.
This change fixes GDB's lack of support for DW_AT_data_bit_offset and
adds an appropriate test case.
gdb/ChangeLog:
PR gdb/12616
* dwarf2read.c (dwarf2_add_field): Handle the DWARF V4 attribute
DW_AT_data_bit_offset.
gdb/testsuite/ChangeLog:
PR gdb/12616
* gdb.dwarf2/nonvar-access.exp: New testcase. Check that GDB
respects the DW_AT_data_bit_offset attribute.
The "struct S" type in bitfield-parent-optimized-out.exp is declared to
have a size of 4 bytes but to hold two 4-byte members: an int-based
bitfield and a 4-byte int. Also, both members have the same
data_member_location 2, causing them to overlap and to reach 2 bytes
beyond the structure's boundary.
This is fixed by increasing the structure size to 8 and setting the
first and second member's data_member_location to 0 and 4, respectively.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/bitfield-parent-optimized-out.exp: Fix DWARF code for
the definition of struct S.
With something like:
struct A { int bitfield:4; } var;
If 'var' ends up wholly-optimized out, printing 'var.bitfield' crashes
gdb here:
(top-gdb) bt
#0 0x000000000058b89f in extract_unsigned_integer (addr=0x2 <error: Cannot access memory at address 0x2>, len=2, byte_order=BFD_ENDIAN_LITTLE)
at /home/pedro/gdb/mygit/src/gdb/findvar.c:109
#1 0x00000000005a187a in unpack_bits_as_long (field_type=0x16cff70, valaddr=0x0, bitpos=16, bitsize=12) at /home/pedro/gdb/mygit/src/gdb/value.c:3347
#2 0x00000000005a1b9d in unpack_value_bitfield (dest_val=0x1b5d9d0, bitpos=16, bitsize=12, valaddr=0x0, embedded_offset=0, val=0x1b5d8d0)
at /home/pedro/gdb/mygit/src/gdb/value.c:3441
#3 0x00000000005a2a5f in value_fetch_lazy (val=0x1b5d9d0) at /home/pedro/gdb/mygit/src/gdb/value.c:3958
#4 0x00000000005a10a7 in value_primitive_field (arg1=0x1b5d8d0, offset=0, fieldno=0, arg_type=0x16d04c0) at /home/pedro/gdb/mygit/src/gdb/value.c:3161
#5 0x00000000005b01e5 in do_search_struct_field (name=0x1727c60 "bitfield", arg1=0x1b5d8d0, offset=0, type=0x16d04c0, looking_for_baseclass=0, result_ptr=0x7fffffffcaf8,
[...]
unpack_value_bitfield is already optimized-out/unavailable -aware:
(...) VALADDR points to the contents of VAL. If the VAL's contents
required to extract the bitfield from are unavailable/optimized
out, DEST_VAL is correspondingly marked unavailable/optimized out.
however, it is not considering the case of the value having no
contents buffer at all, as can happen through
allocate_optimized_out_value.
gdb/ChangeLog:
2016-08-09 Pedro Alves <palves@redhat.com>
* value.c (unpack_value_bitfield): Skip unpacking if the parent
has no contents buffer to begin with.
gdb/testsuite/ChangeLog:
2016-08-09 Pedro Alves <palves@redhat.com>
* gdb.dwarf2/bitfield-parent-optimized-out.exp: New file.
Marin Cermak has found various testcases (or one of them) of GDB FAIL on
ppc64.
https://sourceware.org/bugzilla/show_bug.cgi?id=20328
.o contained only the function descriptor address.
The DWARF as produced by Tcl Dwarf::assemble:
<1><27>: Abbrev Number: 4 (DW_TAG_subprogram)
<28> DW_AT_name : main
<2d> DW_AT_external : 1
<2e> DW_AT_low_pc : 0x1001ff98
<36> DW_AT_high_pc : 0x1002ff98
<2><3e>: Abbrev Number: 5 (DW_TAG_lexical_block)
Runtime info:
$2 = {<text variable, no debug info>} 0x10000674 <.main>
$3 = {void ()} 0x1001ff98 <main>
On Tue, 12 Jul 2016 15:22:49 +0200, Ulrich Weigand wrote:
Well, most of the gdb.dwarf2 test cases simply use explicitly placed labels
for the DW_AT_low_pc / DW_AT_high_pc attributes.
See e.g. dw2-unresolved-main.c:
asm (".globl cu_text_start");
asm ("cu_text_start:");
On Wed, 13 Jul 2016 10:54:00 +0200, Jan Kratochvil wrote:
Now I see I should not do that because:
lib/dwarf.exp:
proc function_range { func src } {
So I am providing this patch.
gdb/testsuite/ChangeLog
2016-07-13 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.dwarf2/atomic-type.exp: Use function_range for low_pc and high_pc.
* gdb.dwarf2/atomic.c (f): Rename f_end_lbl to f_label.
* gdb.dwarf2/dw2-bad-mips-linkage-name.c (f): Rename f_end_lbl to
f_label.
(g): Rename g_end_lbl to g_label.
* gdb.dwarf2/dw2-bad-mips-linkage-name.exp: Use function_range for
low_pc and high_pc.
* gdb.dwarf2/dw2-lexical-block-bare.exp: Likewise.
https://sourceware.org/bugzilla/show_bug.cgi?id=19893
I've traced the main source of the problem to pieced_value_funcs.coerce_ref not being
implemented. Since gdb always assumes references are implemented as pointers, this
causes it to think that it's dealing with a NULL pointer, thus breaking any operations
involving synthetic references.
What I did here was implementing pieced_value_funcs.coerce_ref using some of the synthetic
pointer handling code from indirect_pieced_value, as Pedro suggested. I also made a few
adjustments to the reference printing code so that it correctly shows either the address
of the referenced value or (if it's non-addressable) the "<synthetic pointer>" string.
I also wrote some unit tests based on Dwarf::assemble; these took a while to make
because in most cases I needed a synthetic reference to a physical variable. Additionally,
I started working on a unit test for classes that have a vtable, but ran into a few issues
so that'll probably go in a future patch. One thing that should definitely be fixed is that
proc function_range (called for MACRO_AT_func) will always try to compile/link using gcc
with the default options instead of g++, thus breaking C++ compilations that require e.g. libstdc++.
gdb/ChangeLog:
* dwarf2loc.c (coerce_pieced_ref, indirect_synthetic_pointer,
fetch_const_value_from_synthetic_pointer): New functions.
(indirect_pieced_value): Move lower half to indirect_synthetic_pointer.
(pieced_value_funcs): Implement coerce_ref.
* valops.c (value_addr): Call coerce_ref for synthetic references.
* valprint.c (valprint_check_validity): Return true for synthetic
references. Also, don't show "<synthetic pointer>" if they reference
addressable values.
(generic_val_print_ref): Handle synthetic references. Also move some
code to print_ref_address.
(print_ref_address, get_value_addr_contents): New functions.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/implref.exp: Rename to...
* gdb.dwarf2/implref-const.exp: ...this. Also add more test statements.
* gdb.dwarf2/implref-array.c: New file.
* gdb.dwarf2/implref-array.exp: Likewise.
* gdb.dwarf2/implref-global.c: Likewise.
* gdb.dwarf2/implref-global.exp: Likewise.
* gdb.dwarf2/implref-struct.c: Likewise.
* gdb.dwarf2/implref-struct.exp: Likewise.
Local variables in lambdas are not accessible
https://sourceware.org/bugzilla/show_bug.cgi?id=15231
GDB: read_lexical_block_scope
/* Ignore blocks with missing or invalid low and high pc attributes. */
[...]
if (!dwarf2_get_pc_bounds (die, &lowpc, &highpc, cu, NULL))
return;
But sometimes there is:
FAIL: gcc-5.3.1-6.fc23.x86_64
<2><92>: Abbrev Number: 11 (DW_TAG_lexical_block)
<3><9c>: Abbrev Number: 13 (DW_TAG_structure_type)
<9d> DW_AT_name : (indirect string, offset: 0x3c): <lambda()>
[...]
Where DW_TAG_lexical_block has no attributes. Such whole subtree is currently
dropped by GDB while I think it should just import all its children DIEs.
It even XFAIL->XPASSes gdb.ada/out_of_line_in_inlined.exp:
commit 0fa7fe506c
Author: Joel Brobecker <brobecker@adacore.com>
out of line functions nested inside inline functions.
So I have removed that xfail.
gdb/ChangeLog
2016-05-30 Jan Kratochvil <jan.kratochvil@redhat.com>
PR c++/15231
* dwarf2read.c (enum pc_bounds_kind): Add PC_BOUNDS_INVALID.
(process_psymtab_comp_unit_reader, read_func_scope): Adjust callers.
(read_lexical_block_scope): Import DIEs from bare DW_TAG_lexical_block.
(read_call_site_scope): Adjust callers.
(dwarf2_get_pc_bounds): Implement pc_bounds_invalid.
(dwarf2_get_subprogram_pc_bounds, get_scope_pc_bounds): Adjust callers.
gdb/testsuite/ChangeLog
2016-05-30 Jan Kratochvil <jan.kratochvil@redhat.com>
PR c++/15231
* gdb.ada/out_of_line_in_inlined.exp: Remove xfails.
* gdb.dwarf2/dw2-lexical-block-bare.exp: New file.
gdb/ChangeLog:
* dwarf2loc.c (dwarf2_find_location_expression): For DWO files still
add base_offset.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp (build_executable_from_fission_assembler): Pass
$options when building executable.
* gdb.dwarf2/fission-loclists-pie.c: New file.
* gdb.dwarf2/fission-loclists-pie.exp: New file.
PR symtab/19914
* dwarf2read.c (open_and_init_dwp_file): Look at backlink if objfile
is separate debug file.
testsuite/
* gdb.dwarf2/dwp-sepdebug.c: New file.
* gdb.dwarf2/dwp-sepdebug.exp: New file.
After compiling a program which uses C++ references some optimizations may
convert the references into synthetic "pointers". Trying to print the address
of one of such synthetic references causes gdb to crash with the following
error:
(gdb) print &ref
/build/buildd/gdb-7.7.1/gdb/dwarf2loc.c:1624: internal-error: Should not be able to create a lazy value with an enclosing type
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Apparently, what was causing it was that value_addr returns a copy of the value
that represents the reference with its type set to T* instead of T&. However,
its enclosing_type is left untouched, which fails a check made in
read_pieced_value. We only see the crash happen for references that are
synthetic because they're treated as pieced values, thus the call to
read_pieced_value.
On a related note, it seems that in general there are all sorts of breakage
when working with synthetic references. This is reported here:
https://sourceware.org/bugzilla/show_bug.cgi?id=19893
gdb/ChangeLog:
2016-04-18 Martin Galvan <martin.galvan@tallertechnologies.com>
* valops.c (value_addr): For C++ references, set the copied value's
enclosing_type as well.
gdb/testsuite/ChangeLog:
2016-04-18 Martin Galvan <martin.galvan@tallertechnologies.com>
* gdb.dwarf2/implref.exp: New file.
This patch implements a test that ensures that with "set print object
on", -var-create returns "<optimized out>" for an optimized out pointer
to structure, rather than throwing an error, while also ensuring that
any attempt to dereference the pointer *will* throw an error.
It uses the dwarf assembler to construct the appropriate debug info
to represent a pointer-to-struct in the program as optimized out,
and then accesses that pointer in various ways. The test uses both
the console interpreter and the MI interpreter.
gdb/testsuite/ChangeLog:
2016-04-06 Don Breazeal <donb@codesourcery.com>
* gdb.dwarf2/dw2-opt-structptr.c: New test program.
* gdb.dwarf2/dw2-opt-structptr.exp: New test script.
When running tests in parallel, each test puts its generated files in a
different directory, under "outputs". I think it would be nice if it
was always the case, as it would isolate the test cases a bit more. An
artifact created by a test wouldn't get overwritten by another test.
Also, it makes it easier to clean up. A lot of executables are left all
over the place because their names do not appear in gdb.*/Makefile. If
everything is in "outputs", then we just have to delete that directory
(which we already do).
At the same time it makes the gdb.foo directories and their Makefiles
useless in the build directory, since they are pretty much only used for
cleaning.
What do you think?
gdb/testsuite/ChangeLog:
* Makefile.in (ALL_SUBDIRS): Remove.
(clean mostlyclean): Do not recurse in ALL_SUBDIRS.
(distclean maintainer-clean realclean): Likewise.
* configure.ac (AC_OUTPUT): Remove gdb.*/Makefile.
* configure: Regenerate.
* gdb.ada/Makefile.in: Delete.
* gdb.arch/Makefile.in: Likewise.
* gdb.asm/Makefile.in: Likewise.
* gdb.base/Makefile.in: Likewise.
* gdb.btrace/Makefile.in: Likewise.
* gdb.cell/Makefile.in: Likewise.
* gdb.compile/Makefile.in: Likewise.
* gdb.cp/Makefile.in: Likewise.
* gdb.disasm/Makefile.in: Likewise.
* gdb.dlang/Makefile.in: Likewise.
* gdb.dwarf2/Makefile.in: Likewise.
* gdb.fortran/Makefile.in: Likewise.
* gdb.gdb/Makefile.in: Likewise.
* gdb.go/Makefile.in: Likewise.
* gdb.guile/Makefile.in: Likewise.
* gdb.java/Makefile.in: Likewise.
* gdb.linespec/Makefile.in: Likewise.
* gdb.mi/Makefile.in: Likewise.
* gdb.modula2/Makefile.in: Likewise.
* gdb.multi/Makefile.in: Likewise.
* gdb.objc/Makefile.in: Likewise.
* gdb.opencl/Makefile.in: Likewise.
* gdb.opt/Makefile.in: Likewise.
* gdb.pascal/Makefile.in: Likewise.
* gdb.perf/Makefile.in: Likewise.
* gdb.python/Makefile.in: Likewise.
* gdb.reverse/Makefile.in: Likewise.
* gdb.server/Makefile.in: Likewise.
* gdb.stabs/Makefile.in: Likewise.
* gdb.threads/Makefile.in: Likewise.
* gdb.trace/Makefile.in: Likewise.
* gdb.xml/Makefile.in: Likewise.
* lib/gdb.exp (make_gdb_parallel_path): Add check for
GDB_PARALLEL.
(standard_output_file): Remove check for GDB_PARALLEL, always
return path in outputs/$subdir/$testname.
It is possible to use multiple base addresses within a single address
range series, within the .debug_ranges section. The following is a
simplified example for 32-bit addresses:
.section ".debug_ranges"
.4byte 0xffffffff
.4byte BASE_1
.4byte START_OFFSET_1
.4byte END_OFFSET_1
.4byte START_OFFSET_2
.4byte END_OFFSET_2
.4byte 0xffffffff
.4byte BASE_2
.4byte START_OFFSET_3
.4byte END_OFFSET_3
.4byte 0
.4byte 0
In this example START/END 1 and 2 are relative to BASE_1, while
START/END 3 are relative to BASE_2.
Currently gdb does not correctly parse this DWARF, resulting in
corrupted address range information. This commit fixes this issue, and
adds a new test to cover this case.
In order to support testing of this feature extensions were made to the
testsuite dwarf assembler, additional functionality was added to the
.debug_line generation function, and a new function for generating the
.debug_ranges section was added.
gdb/ChangeLog:
* dwarf2read.c (dwarf2_ranges_read): Unify and fix base address
reading code.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/dw2-ranges-base.c: New file.
* gdb.dwarf2/dw2-ranges-base.exp: New file.
* lib/dwarf.exp (namespace eval Dwarf): Add new variables to
support additional line table, and debug ranges generation.
(Dwarf::ranges): New function, generate .debug_ranges.
(Dwarf::lines): Support generating simple line table programs.
(Dwarf::assemble): Initialise new namespace variables.
Some of the source code for the test cases in the GDB testsuite
reside in .S files containing assembly code. These files typically
define a symbol - such as main - which may, depending on the target,
require a prefix such as underscore.
For example, gdb.dwarf2/dw-compdir-oldgcc.S defines the symbol main:
main: .globl main
Some targets, such as rx-elf, require main to have an underscore
prefix. (If it doesn't, a linker error results due to not being able
to find _main required by crt0.o.) So, instead, the above should look
like this for rx-elf and other targets with this same requirement:
_main: .globl _main
This patch defines a new tcl proc in lib/gdb named
gdb_target_symbol_prefix_flags_asm. This proc returns a string
which will - assuming everything else is wired up correctly - cause
-DSYMBOL_PREFIX=_ to be passed on the command line to the compiler.
The test cases are augmented with a macro definition for SYMBOL
as follows:
#define CONCAT1(a, b) CONCAT2(a, b)
#define CONCAT2(a, b) a ## b
#ifdef SYMBOL_PREFIX
# define SYMBOL(str) CONCAT1(SYMBOL_PREFIX, str)
#else
# define SYMBOL(str) str
#endif
Symbols, such as main shown in the example earlier are then wrapped
with SYMBOL like this:
SYMBOL(main): .globl SYMBOL(main)
The net effect will be to add a prefix for those targets which need
it and add no prefix for those targets which do not.
It should be noted that there was already a proc in lib/gdb.exp
called gdb_target_symbol_prefix_flags. It still exists, but has
been significantly rewritten. (There is only one small difference
between the two versions.)
That proc used to explicitly list targets which were known to
require an underscore prefix. This is no longer done; the recently
added proc, gdb_target_symbol_prefix, is now invoked to dynamically
discover whether or not a prefix is required for that particular
target.
The difference between gdb_target_symbol_prefix_flags_asm
and gdb_target_symbol_prefix_flags is that the former returns
a bare prefix while the latter returns the prefix enclosed in
double quotes. I.e. assuming that the discovered prefix is
underscore, gdb_target_symbol_prefix_flags_asm returns:
additional_flags=-DSYMBOL_PREFIX=_
while gdb_target_symbol_prefix_flags returns:
additional_flags=-DSYMBOL_PREFIX="_"
The double-quoted version is not suitable for using with .S files
containing assembly code; there is no way to strip the double quotes
using C preprocessor constructs.
It would be possible to use the bare (non double quoted) version in
C source code. However, the supporting macros become more complicated
and therefore more difficult to maintain.
gdb/testsuite/ChangeLog:
* lib/gdb (gdb_target_symbol_prefix_flags_asm): New proc.
(gdb_target_symbol_prefix_flags): Define in terms of _asm
version.
* gdb.arch/i386-float.exp, gdb.arch/i386-permbkpt.exp,
gdb.dwarf2/dw2-canonicalize-type.exp,
gdb.dwarf2/dw2-compdir-oldgcc.exp, gdb.dwarf2/dw2-minsym-in-cu.exp,
gdb.dwarf2/dw2-op-stack-value.exp, gdb.dwarf2/dw2-unresolved.exp,
gdb.dwarf2/fission-reread.exp, gdb.dwarf2/pr13961.exp: Use flags
provided by gdb_target_symbol_prefix_flags_asm.
* gdb.dwarf2/dw2-canonicalize-type.S, gdb.dwarf2/dw2-compdir-oldgcc.S,
testsuite/gdb.dwarf2/dw2-minsym-in-cu.S,
testsuite/gdb.dwarf2/dw2-unresolved-main.c,
testsuite/gdb.dwarf2/dw2-unresolved.S, gdb.dwarf2/fission-reread.S,
gdb.dwarf2/pr13961.S: Define and use SYMBOL macro (and supporting
macros where needed). Use this macro for symbols which require
the prefix provided by SYMBOL_PREFIX.
Some of the tests in gdb.dwarf2 which use Dwarf::assemble refer to
(minimal/linker) symbols created in the course of building a small
test program. Some targets use a prefix such as underscore ("_") on
these symbols. Many of the tests in gdb.dwarf2 do not take this into
account. As a consequence, these tests fail to build, resulting
either in failures or untested testcases.
Here is an example from gdb.dwarf2/dw2-regno-invalid.exp:
Dwarf::assemble $asm_file {
cu {} {
compile_unit {
{low_pc main DW_FORM_addr}
{high_pc main+0x10000 DW_FORM_addr}
} {
...
}
For targets which require an underscore prefix on linker symbols,
the two occurrences of "main" would have to have a prepended underscore,
i.e. _main instead of main.
For the above case, a call to the new proc gdb_target_symbol is used
prepend the correct prefix to the symbol. I.e. the above code is
rewritten (as shown in the patch) as follows:
Dwarf::assemble $asm_file {
cu {} {
compile_unit {
{low_pc [gdb_target_symbol main] DW_FORM_addr}
{high_pc [gdb_target_symbol main]+0x10000 DW_FORM_addr}
} {
...
}
I also found it necessary to make an adjustment to lib/dwarf.exp so that
expressions of more than just one list element can be used in DW_TAG_...
constructs. Both atomic-type.exp and dw2-bad-mips-linkage-name.exp require
this new functionality.
gdb/testsuite/ChangeLog:
* lib/gdb.exp (gdb_target_symbol_prefix, gdb_target_symbol):
New procs.
* lib/dwarf.exp (_handle_DW_TAG): Handle attribute values,
representing expressions, of more than one list element.
* gdb.dwarf2/atomic-type.exp (Dwarf::assemble): Use gdb_target_symbol
to prepend linker symbol prefix to f.
* gdb.dwarf2/data-loc.exp (Dwarf::assemble): Likewise, for
table_1 and table_2.
* gdb.dwarf2/dw2-bad-mips-linkage-name.exp (Dwarf::assemble):
Likewise, for f and g.
* gdb.dwarf2/dw2-ifort-parameter.exp (Dwarf::assemble): Likewise,
for ptr.
* gdb.dwarf2/dw2-regno-invalid.exp (Dwarf::assemble): Likewise,
for main.
* gdb.dwarf2/dynarr-ptr.exp (Dwarf::assemble): Likewise, for
table_1_ptr and table_2_ptr.
2015-10-02 Sandra Loosemore <sandra@codesourcery.com>
gdb/testsuite/
* gdb.dwarf2/staticvirtual.exp: Generalize regexp so it can match
whether or not address 0x1000 is mapped on the target.
bfd/ChangeLog:
* targets.c (enum bfd_flavour): Add comment.
(bfd_flavour_name): New function.
* bfd-in2.h: Regenerate.
gdb/ChangeLog:
* findvar.c (default_read_var_value) <LOC_UNRESOLVED>: Include the
kind of minimal symbol in the error message.
* objfiles.c (objfile_flavour_name): New function.
* objfiles.h (objfile_flavour_name): Declare.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/dw2-bad-unresolved.c: New file.
* gdb.dwarf2/dw2-bad-unresolved.exp: New file.
Here, in dwarfread.c:process_full_comp_unit:
/* Set symtab language to language from DW_AT_language. If the
compilation is from a C file generated by language preprocessors, do
not set the language if it was already deduced by start_subfile. */
if (!(cu->language == language_c
&& COMPUNIT_FILETABS (cust)->language != language_c))
COMPUNIT_FILETABS (cust)->language = cu->language;
in case start_subfile doesn't manage to deduce a language
COMPUNIT_FILETABS(cust)->language ends up as language_unknown, not
language_c. So the condition above evals false and we never set the
language from the cu's language.
gdb/ChangeLog:
2015-08-20 Pedro Alves <palves@redhat.com>
* dwarf2read.c (process_full_comp_unit): To tell whether
start_subfile managed to deduce a language, test for
language_unknown instead of language_c.
gdb/testsuite/ChangeLog:
2015-08-20 Pedro Alves <palves@redhat.com>
* gdb.dwarf2/comp-unit-lang.exp: New file.
* gdb.dwarf2/comp-unit-lang.c: New file.
This change introduces a new function, dwarf2_string_attr(), which is
a wrapper for dwarf2_attr(). dwarf2read.c has been updated to
call dwarf2_string_attr in most instances where a string-valued
attribute is decoded to produce a string value. In most cases, it
simplifies the code; in some instances, the complexity of the code
remains unchanged.
I performed this change by looking for instances where the
result of DW_STRING was used in an assignment. Many of these
had a pattern which (roughly) looks something like this:
struct attribute *attr = NULL;
attr = dwarf2_attr (die, name, cu);
if (attr != NULL && DW_STRING (attr))
{
const char *str;
...
str = DW_STRING (attr);
... /* Use str in some fashion. */
}
Code of this form is transformed to look like this instead:
const char *str;
str = dwarf2_string_attr (die, name, cu)
if (str != NULL)
{
...
/* Use str in some fashion. */
...
}
In addition to invoking dwarf2_attr() and DW_STRING(),
dwarf2_string_attr() checks to make sure that the attribute's
`form' field matches one of DW_FORM_strp, DW_FORM_string, or
DW_FORM_GNU_strp_alt. If it does not match one of these forms,
it will return a NULL value in addition to calling complaint().
An earlier version of this patch did this type checking for one
particular instance where a string attribute was being decoded.
The situation that I was attempting to handle in that earlier patch is
this:
The Texas Instruments compiler uses the encoding for
DW_AT_MIPS_linkage_name for other purposes. TI uses the encoding,
0x2007, for TI_AT_TI_end_line which, unlike DW_AT_MIPS_linkage_name,
does not have a string-typed value. In this instance, GDB was attempting
to use an integer value as a string pointer, with predictable results.
(GDB would die with a segmentation fault.)
I've added a test which reproduces the problem that I was orignally
wanting to fix. It uses DW_AT_MIPS_linkage name with an associate
value which is a string, and again, where the value is a small
integer.
My test case causes GDB to segfault in an unpatched GDB. There
will be two PASSes in a patched GDB.
Unpatched GDB:
(gdb) ptype f
ERROR: Process no longer exists
UNRESOLVED: gdb.dwarf2/dw2-bad-mips-linkage-name.exp: ptype f
ERROR: Couldn't send ptype g to GDB.
UNRESOLVED: gdb.dwarf2/dw2-bad-mips-linkage-name.exp: ptype g
Patched GDB:
(gdb) ptype f
type = bool ()
(gdb) PASS: gdb.dwarf2/dw2-bad-mips-linkage-name.exp: ptype f
ptype g
type = bool ()
(gdb) PASS: gdb.dwarf2/dw2-bad-mips-linkage-name.exp: ptype g
I see no regressions on an x86_64 native target.
gdb/ChangeLog:
* dwarf2read.c (dwarf2_string_attr): New function.
(lookup_dwo_unit, process_psymtab_comp_unit_reader)
(dwarf2_compute_name, dwarf2_physname, find_file_and_directory)
(read_call_site_scope, namespace_name, guess_full_die_structure_name)
(anonymous_struct_prefix, prepare_one_comp_unit): Use
dwarf2_string_attr in place of dwarf2_attr and DW_STRING.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/dw2-bad-mips-linkage-name.c: New file.
* gdb.dwarf2/dw2-bad-mips-linkage-name.exp: New file.
Dummy CUs are used by the incremental linker to pre-allocate space
in the output file. They have a DWARF header but no contents.
gdb/ChangeLog:
* dwarf2read.c (dwarf2_per_cu_data): Add comment.
(load_cu): Handle dummy CUs.
(dw2_do_instantiate_symtab, process_queuef): Ditto.
(dwarf2_fetch_die_loc_sect_off, dwarf2_fetch_constant_bytes): Ditto.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/dw2-dummy-cu.S: New file.
* gdb.dwarf2/dw2-dummy-cu.exp: New file.
I see many fails in gdb.dwarf2/dynarr-ptr.exp on arm-linux target,
started from this
print foo.three_ptr.all^M
Cannot access memory at address 0x107c8^M
(gdb) FAIL: gdb.dwarf2/dynarr-ptr.exp: print foo.three_ptr.all
print foo.three_ptr.all(1)^M
Cannot access memory at address 0x107c8
It turns out that ":$ptr_size" is used incorrectly.
array_ptr_label: DW_TAG_pointer_type {
{DW_AT_byte_size :$ptr_size }
^^^^^^^^^^
{DW_AT_type :$array_label}
}
Since the FORM isn't given, and it starts with the ":", it is regarded
as a label reference by dwarf assembler. The generated asm file on
x86_64 is
.uleb128 6 /* Abbrev (DW_TAG_pointer_type) */
.4byte 8 - .Lcu1_begin <----- WRONG
.4byte .Llabel2 - .Lcu1_begin
Looks .Lcu1_begin is 0 on x86_64 and that is why this test passes on
x86_64. On arm, .Lcu1_begin is an address somewhere, and the value
of DW_AT_byte_size is a very large number, so memory read request
of such large length failed.
This patch is to remove ":" and set the form explicitly. The generated
asm file on x86_64 becomes
.uleb128 6 /* Abbrev (DW_TAG_pointer_type) */
.byte 8
.4byte .Llabel2 - .Lcu1_begin
gdb/testsuite:
2015-04-15 Yao Qi <yao.qi@linaro.org>
* gdb.dwarf2/dynarr-ptr.exp (assemble): Use $ptr_size instead
of ":$ptr_size" and set its form explicitly.
Variables with a DW_AT_const_value but without a DW_AT_location were not
getting added to the partial symbol table. They are added to the full
symbol table, however, when the compilation unit's psymtabs are
expanded.
Before:
(gdb) p one
No symbol "one" in current context.
(gdb) mt flush-symbol-cache
(gdb) mt expand one.c
(gdb) p one
$1 = 1
After:
(gdb) p one
$1 = 1
To the user it's pretty strange, as depending on whether tab completion
has forced expansion of all CUs or not the lookup might succeed, or not
if the failure was already added to the symbol cache.
This commit simply makes sure to add constants to the partial symbol
tables.
gdb/testsuite/ChangeLog:
PR symtab/18148
* gdb.dwarf2/dw2-intercu.S (one, two): Add variables that have a
const_value but not a location.
* gdb.dwarf2/dw2-intercu.exp: Add tests that constants without
location defined in non-main CUs are visible.
gdb/ChangeLog:
PR symtab/18148
* dwarf2read.c (struct partial_die_info): Add has_const_value
member.
(add_partial_symbol): Don't punt on symbols that have const_value
attributes.
(read_partial_die): Detect DW_AT_const_value.
This bug appears to be caused by bad debuginfo. The method
causing the sefault in the reporter's test case is marked both static
and virtual.
This patch simply safegaurds against this case in dwarf2_add_member_fn,
where the code assumes that there is a `this' pointer when a virtual method
is seen (more specifically, when DW_AT_vtable_elem is seen).
It previously dereferenced the first formal parameter
(`this' pointer), which in this case doesn't exist. GDB consequently
segfaulted dereferencing a NULL pointer.
gdb/ChangeLog
PR gdb/18021
* dwarf2read.c (dwarf2_add_member_fn): Issue a complaint
if we find a static method with DW_AT_vtable_elem_location.
gdb/testsuite/ChangeLog
PR gdb/18021
* gdb.dwarf2/staticvirtual.exp: New test.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp (Dwarf): Flag an error if a numeric attribute value
is given without an explicit form.
* gdb.dwarf2/arr-subrange.exp: Specify forms for all numeric
attributes.
* gdb.dwarf/corrupt.exp: Ditto.
* gdb.dwarf2/enum-type.exp: Ditto.
* gdb.trace/entry-values.exp: Ditto.
* gdb.trace/unavailable-dwarf-piece.exp: Ditto.
Address issues triggered by the MIPS ISA bit handling change, usually in
tests that make artificial DWARF-2 records:
* gdb.cp/expand-psymtabs-cxx.exp -- this test is debugging an object file
and assuming addresses will be 0; with the ISA bit set code addresses
are 1 instead:
(gdb) PASS: gdb.cp/expand-psymtabs-cxx.exp: set language c++
p 'method(long)'
$1 = {void (long)} 0x1 <method(long)>
(gdb) FAIL: gdb.cp/expand-psymtabs-cxx.exp: before expand
p method
$2 = {void (long)} 0x1 <method(long)>
(gdb) FAIL: gdb.cp/expand-psymtabs-cxx.exp: force expand
p 'method(long)'
$3 = {void (long)} 0x1 <method(long)>
(gdb) FAIL: gdb.cp/expand-psymtabs-cxx.exp: after expand
Fix by matching any hex number, there's no value AFAICT for the test
in matching 0 exactly, and I suppose the method's offset within
section can be non-zero for some other reasons on other targets too.
* gdb.cp/nsalias.exp -- this assumes instructions can be aligned
arbitrarily and places code labels at odd addreses, setting the ISA
bit and wreaking havoc:
(gdb) PASS: gdb.cp/nsalias.exp: print outer::inner::innermost::x
list outer::inner::innermost::foo
Function "outer::inner::innermost::foo" not defined.
(gdb) FAIL: gdb.cp/nsalias.exp: list outer::inner::innermost::foo
break *outer::inner::innermost::foo
No symbol "foo" in namespace "outer::inner::innermost".
(gdb) FAIL: gdb.cp/nsalias.exp: setting breakpoint at
*outer::inner::innermost::foo
delete $bpnum
No breakpoint number 6.
(gdb) FAIL: gdb.cp/nsalias.exp: (outer::inner::innermost): delete $bpnum
-- etc., etc... Fix by aligning labels to 4; required by many
processors.
* gdb.dwarf2/dw2-canonicalize-type.exp, gdb.dwarf2/dw2-empty-pc-range.exp,
gdb.dwarf2/pr11465.exp -- these assume an instruction and consequently
a function can take as little as 1 byte, which makes it impossible to
look up a code symbol by an address with the ISA bit set as the
address is already beyond the end of the function:
(gdb) ptype f
No symbol "f" in current context.
(gdb) FAIL: gdb.dwarf2/dw2-canonicalize-type.exp: ptype f
(gdb) PASS: gdb.dwarf2/dw2-empty-pc-range.exp: empty range before CU load
ptype realrange
No symbol "realrange" in current context.
(gdb) FAIL: gdb.dwarf2/dw2-empty-pc-range.exp: valid range after CU load
(gdb) p N::c.C
Cannot take address of method C.
(gdb) FAIL: gdb.dwarf2/pr11465.exp: p N::c.C
-- fix by increasing the size of the function to 4 (perhaps code in
gdb/mips-tdep.c could look up code symbols up to twice, with and
failing that without the ISA bit set, but it seems wrong to me to
implement specific handling for invalid code just to satisfy test
cases that assume too much about the target).
* gdb.dwarf2/dw2-case-insensitive.exp -- an artificial code label is
created, but does not work because data (a `.align' pseudo-op in this
case) follows and as a result the label has no MIPS16 or microMIPS
annotation in the symbol table:
(gdb) PASS: gdb.dwarf2/dw2-case-insensitive.exp: set case-sensitive off
info functions fUnC_lang
All functions matching regular expression "fUnC_lang":
File file1.txt:
foo FUNC_lang(void);
Non-debugging symbols:
0x004006e0 FUNC_lang_start
(gdb) FAIL: gdb.dwarf2/dw2-case-insensitive.exp: regexp case-sensitive off
-- fix by adding a `.insn' pseudo-op on MIPS targets; the pseudo-op
marks data as instructions.
* gdb.dwarf2/dw2-stack-boundary.exp -- the test case enables complaints
and assumes none will be issued beyond ones explicitly arranged by the
test case, however overlapping sections are noticed while minimal
symbols are looked up by `mips_adjust_dwarf2_addr' in DWARF-2 record
processing:
(gdb) set complaints 100
(gdb) PASS: gdb.dwarf2/dw2-stack-boundary.exp: set complaints 100
file ./dw2-stack-boundary
Reading symbols from ./dw2-stack-boundary...location description stack
underflow...location description stack overflow...unexpected overlap
between:
(A) section `.reginfo' from `.../gdb.dwarf2/dw2-stack-boundary' [0x0, 0x18)
(B) section `*COM*' from `.../gdb.dwarf2/dw2-stack-boundary' [0x0, 0x0).
Will ignore section B...unexpected overlap between:
(A) section `.reginfo' from `.../gdb.dwarf2/dw2-stack-boundary' [0x0, 0x18)
(B) section `*UND*' from `.../gdb.dwarf2/dw2-stack-boundary' [0x0, 0x0).
Will ignore section B...unexpected overlap between:
(A) section `.reginfo' from `.../gdb.dwarf2/dw2-stack-boundary' [0x0, 0x18)
(B) section `*ABS*' from `.../gdb.dwarf2/dw2-stack-boundary' [0x0, 0x0).
Will ignore section B...done.
(gdb) FAIL: gdb.dwarf2/dw2-stack-boundary.exp: check partial symtab errors
-- fix by ignoring any extra noise as long as what we look for is
found.
* gdb.cp/expand-psymtabs-cxx.exp: Accept any address of
`method(long)', not just 0x0.
* gdb.cp/nsalias.exp: Align code labels to 4.
* gdb.dwarf2/dw2-canonicalize-type.S (main): Expand to 4-bytes.
* gdb.dwarf2/dw2-empty-pc-range.S (main): Likewise.
* gdb.dwarf2/pr11465.S (_ZN1N1cE): Likewise.
* gdb.dwarf2/dw2-case-insensitive.c (START_INSNS): New macro.
(cu_text_start, FUNC_lang_start): Use `START_INSNS'.
* gdb.dwarf2/dw2-stack-boundary.exp: Accept noise in complaints.
Python 3's print requires to use parentheses, so this patch adds them
where they were missing.
gdb/testsuite/ChangeLog:
* gdb.ada/py_range.exp: Add parentheses to calls to print.
* gdb.dwarf2/symtab-producer.exp: Same.
* gdb.gdb/python-interrupts.exp: Same.
* gdb.gdb/python-selftest.exp: Same.
* gdb.python/py-linetable.exp: Same.
* gdb.python/py-type.exp: Same.
* gdb.python/py-value-cc.exp: Same.
* gdb.python/py-value.exp: Same.
This patch fixes two fails in dw2-compdir-oldgcc.exp I've seen on arm
target thumb mode.
FAIL: gdb.dwarf2/dw2-compdir-oldgcc.exp: info source gcc42
FAIL: gdb.dwarf2/dw2-compdir-oldgcc.exp: info source gcc43
When fill in DW_AT_low_pc, the label should be used rather than the
function, otherwise, the LSB bit of the address in DW_AT_low_pc is
set and the debug info is wrong. This patch is to add two labels for
functions gcc42 and gcc43 respectively, and use them. These two
fails are fixed.
gdb/testsuite:
2014-11-22 Yao Qi <yao@codesourcery.com>
* gdb.dwarf2/dw2-compdir-oldgcc.S: Define label .Lgcc42_procstart
and .Lgcc43_procstart. Use .Lgcc42_procstart instead of gcc42.
Use .Lgcc43_procstart instead of gcc43.
Andreas Arnez
Jan Kratochvil
Yao Qi
Joel Brobecker
Luis Machado
Tom Tromey
Pedro Alves
Martin Galvan
Doug Evans
Don Breazeal
Simon Marchi
Andrew Burgess
Kevin Buettner
Sandra Loosemore
Doug Evans
Pierre-Marie de Rodat
Andy Wingo
Keith Seitz
Mark Wielaard
Maciej W. Rozycki
Yao Qi