As described in the log of patch "gdb/dwarf: add assertion in
maybe_queue_comp_unit", it would happen that a call to
maybe_queue_comp_unit would enqueue a CU in the to-expand queue while
nothing up the stack was processing the queue. This is not desirable,
as items are then left lingering in the queue when we exit the
dwarf2/read code. This is an inconsistent state.
The normal case of using the queue is when we go through
dw2_do_instantiate_symtab and process_queue. As depended-on CUs are
found, they get added to the queue. process_queue expands CUs until the
queue is empty.
To catch these cases where things are enqueued while nothing up the
stack is processing the queue, change dwarf2_per_bfd::queue to be an
optional. The optional is instantiated in dwarf2_queue_guard, just
before where we call process_queue. In the dwarf2_queue_guard
destructor, the optional gets reset. Therefore, the queue object is
instantiated only when something up the stack is handling it. If
another entry point tries to enqueue a CU for expansion, an assertion
will fail and we know we have something to fix.
dwarf2_queue_guard sounds like the good place for this, as it's
currently responsible for making sure the queue gets cleared if we exit
due to an error.
This also allows asserting that when age_comp_units or remove_all_cus
run, the queue is not instantiated, and gives us one more level of
assurance that we won't free the DIEs of a CU that is in the
CUs-to-expand queue.
gdb/ChangeLog:
PR gdb/26828
* dwarf2/read.c (dwarf2_queue_guard) <dwarf2_queue_guard>:
Instantiate queue.
(~dwarf2_queue_guard): Clear queue.
(queue_comp_unit): Assert that queue is
instantiated.
(process_queue): Adjust.
* dwarf2/read.h (struct dwarf2_per_bfd) <queue>: Make optional.
Change-Id: I8fe3d77845bb4ad3d309eac906acebe79d9f0a9d
The previous commit log described how items could be left lingering in
the dwarf2_per_bfd::queue and how that could cause trouble.
This patch fixes the issue by changing maybe_queue_comp_unit so that it
doesn't put a CU in the to-expand queue if that CU is already expanded.
This will make it so that when dwarf2_fetch_die_type_sect_off calls
follow_die_offset and maybe_queue_comp_unit, it won't enqueue the target
CU, because it will see the CU is already expanded.
This assumes that if a CU is dwarf2_fetch_die_type_sect_off's target CU,
it will have previously been expanded. I think it is the case, but I
can't be 100% sure. If that's not true, the assertions added in the
following patch will catch it, and it means we'll have to re-think a bit
more how things work (it wouldn't be well handled at all today anyway).
This fixes something else in maybe_queue_comp_unit that looks wrong.
Imagine the DIEs of a CU are loaded in memory, but that CU is not
expanded. In that case, maybe_queue_comp_unit will use this early
return:
/* If the compilation unit is already loaded, just mark it as
used. */
dwarf2_cu *cu = per_objfile->get_cu (per_cu);
if (cu != nullptr)
{
cu->last_used = 0;
return 0;
}
... so the CU won't be queued for expansion. Whether the DIEs of a CU
are loaded in memory and whether that CU is expanded are two orthogonal
things, but that function appears to mix them. So, move the queuing
above that check / early return, so that if the CU's DIEs are loaded in
memory but the CU is not expanded yet, it gets enqueued.
I tried to improve maybe_queue_comp_unit's documentation to clarify what
the return value means. By clarifying this, I noticed that two callers
(follow_die_offset and follow_die_sig_1) access the CU's DIEs after
calling maybe_queue_comp_unit, only relying on maybe_queue_comp_unit's
return value to tell whether DIEs need to be loaded first or not. As
explained in the new comment, this is problematic:
maybe_queue_comp_unit's return value doesn't tell whether DIEs are
currently loaded, it means whether maybe_queue_comp_unit requires the
caller to load them. If the CU is already expanded but the DIEs to have
been freed, maybe_queue_comp_unit returns 0, meaning "I don't need you
to load the DIEs". So if these two functions (follow_die_offset and
follow_die_sig_1) need to access the DIEs in any case, for their own
usage, they should make sure to load them if they are not loaded
already. I therefore added an extra check to the condition they use,
making it so they will always load the DIEs if they aren't already.
From what I found, other callers don't care for the CU's DIEs, they call
maybe_queue_comp_unit to ensure the CU gets expanded eventually, but
don't care for it after that.
gdb/ChangeLog:
PR gdb/26828
* dwarf2/read.c (maybe_queue_comp_unit): Check if CU is expanded
to decide whether or not to enqueue it for expansion.
(follow_die_offset, follow_die_sig_1): Ensure we load the DIEs
after calling maybe_queue_comp_unit.
Change-Id: Id98c6b60669f4b4b21b9be16d0518fc62bdf686a
Delete two more symbol/section related macros. This time it's
SYMBOL_SECTION and MSYMBOL_SECTION.
As with general_symbol_info::m_name it is not currently possible to
make general_symbol_info::m_section private as general_symbol_info
must remain a POD type.
But other than failing to make the new m_section private, this change
does what you'd expect, adds a get and set member function and updates
all users to use the new functions instead of the previous wrapper
macros.
There should be no user visible change after this commit.
gdb/ChangeLog:
* coff-pe-read.c (add_pe_forwarded_sym): Make use of section_index
and set_section_index member functions where appropriate.
* coffread.c (coff_symtab_read): Likewise.
(process_coff_symbol): Likewise.
* ctfread.c (set_symbol_address): Likewise.
* dwarf2/read.c (add_partial_symbol): Likewise.
(var_decode_location): Likewise.
* language.c: Likewise.
* minsyms.c (minimal_symbol_reader::record_full): Likewise.
(compact_minimal_symbols): Likewise.
(minimal_symbol_upper_bound): Likewise.
* objfiles.c (relocate_one_symbol): Likewise.
* psympriv.h (partial_symbol::obj_section): Likewise.
(partial_symbol::address): Likewise.
* psymtab.c (partial_symtab::add_psymbol): Likewise.
* stabsread.c (scan_file_globals): Likewise.
* symmisc.c (dump_msymbols): Likewise.
* symtab.c (general_symbol_info::obj_section): Likewise.
(fixup_section): Likewise.
(get_msymbol_address): Likewise.
* symtab.h (general_symbol_info::section): Rename to...
(general_symbol_info::m_section): ...this.
(general_symbol_info::set_section_index): New member function.
(general_symbol_info::section_index): Likewise.
(SYMBOL_SECTION): Delete.
(MSYMBOL_VALUE_ADDRESS): Make use of section_index and
set_section_index member functions where appropriate.
(MSYMBOL_SECTION): Delete.
(symbol::symbol): Update to initialize 'm_section'.
* xcoffread.c (read_xcoff_symtab): Make use of set_section_index.
(process_xcoff_symbol): Likewise.
When running test-case gdb.fortran/function-calls.exp with target board
unix/gdb:debug_flags=-gdwarf-5, I run into:
...
(gdb) PASS: gdb.fortran/function-calls.exp: \
p derived_types_and_module_calls::pass_cart(c)
p derived_types_and_module_calls::pass_cart_nd(c_nd)^M
^M
Program received signal SIGSEGV, Segmentation fault.^M
0x0000000000400f73 in derived_types_and_module_calls::pass_cart_nd \
(c=<error reading variable: Cannot access memory at address 0xc>) at \
function-calls.f90:130^M
130 pass_cart_nd = ubound(c%d,1,4)^M
The program being debugged was signaled while in a function called from GDB.^M
GDB has restored the context to what it was before the call.^M
To change this behavior use "set unwindonsignal off".^M
Evaluation of the expression containing the function^M
(derived_types_and_module_calls::pass_cart_nd) will be abandoned.^M
(gdb) FAIL: gdb.fortran/function-calls.exp: p
...
The problem originates in read_array_type, when reading a DW_TAG_array_type
with a dwarf-5 DW_TAG_generic_subrange child. This is not supported, and the
fallout of this is that rather than constructing a new array type, the code
proceeds to modify the element type.
Fix this conservatively by issuing a complaint and bailing out in
read_array_type when not being able to construct an array type, such that we
have:
...
(gdb) maint expand-symtabs function-calls.f90^M
During symbol reading: unable to find array range \
- DIE at 0xe1e [in module function-calls]^M
During symbol reading: unable to find array range \
- DIE at 0xe1e [in module function-calls]^M
(gdb) KFAIL: gdb.fortran/function-calls.exp: no complaints in srcfile \
(PRMS: symtab/27388)
...
Tested on x86_64-linux.
gdb/ChangeLog:
2021-02-09 Tom de Vries <tdevries@suse.de>
PR symtab/27341
* dwarf2/read.c (read_array_type): Return NULL when not being able to
construct an array type. Add assert to ensure that element_type is
not being modified.
gdb/testsuite/ChangeLog:
2021-02-09 Tom de Vries <tdevries@suse.de>
PR symtab/27341
* lib/gdb.exp (with_complaints): New proc, factored out of ...
(gdb_load_no_complaints): ... here.
* gdb.fortran/function-calls.exp: Add test-case.
When running test-case gdb.cp/cpexprs-debug-types.exp with target board
unix/gdb:debug_flags=-gdwarf-5, I run into:
...
(gdb) file cpexprs-debug-types^M
Reading symbols from cpexprs-debug-types...^M
ERROR: Couldn't load cpexprs-debug-types into GDB (eof).
ERROR: Couldn't send delete breakpoints to GDB.
ERROR: GDB process no longer exists
GDB process exited with wait status 23054 exp9 0 0 CHILDKILLED SIGABRT SIGABRT
...
We're running into this abort in process_psymtab_comp_unit:
...
switch (reader.comp_unit_die->tag)
{
case DW_TAG_compile_unit:
this_cu->unit_type = DW_UT_compile;
break;
case DW_TAG_partial_unit:
this_cu->unit_type = DW_UT_partial;
break;
default:
abort ();
}
...
because reader.comp_unit_die->tag == DW_TAG_type_unit.
Fix this by adding a DW_TAG_type_unit case.
Tested on x86_64-linux.
gdb/ChangeLog:
2021-02-05 Tom de Vries <tdevries@suse.de>
PR symtab/27333
* dwarf2/read.c (process_psymtab_comp_unit): Handle DW_TAG_type_unit.
When running test-case gdb.dwarf2/clang-debug-names.exp, I run into the
following warning:
...
(gdb) file clang-debug-names^M
Reading symbols from clang-debug-names...^M
warning: Section .debug_aranges in clang-debug-names has duplicate \
debug_info_offset 0xc7, ignoring .debug_aranges.^M
...
This is caused by a missing return in commit 3ee6bb113a "[gdb/symtab] Fix
incomplete CU list assert in .debug_names".
Fix this by adding the missing return, such that we have instead this warning:
...
(gdb) file clang-debug-names^M
Reading symbols from clang-debug-names...^M
warning: Section .debug_aranges in clang-debug-names \
entry at offset 0 debug_info_offset 0 does not exists, \
ignoring .debug_aranges.^M
...
which is a known problem filed as PR25969 - "Ignoring .debug_aranges with
clang .debug_names".
Tested on x86_64-linux.
gdb/ChangeLog:
2021-02-05 Tom de Vries <tdevries@suse.de>
PR symtab/27307
* dwarf2/read.c (create_cus_from_debug_names_list): Add missing
return.
gdb/testsuite/ChangeLog:
2021-02-05 Tom de Vries <tdevries@suse.de>
PR symtab/27307
* gdb.dwarf2/clang-debug-names.exp: Check file command warnings.
Fix indentation in !map.augmentation_is_gdb part of
create_cus_from_debug_names_list.
gdb/ChangeLog:
2021-02-05 Tom de Vries <tdevries@suse.de>
* dwarf2/read.c (create_cus_from_debug_names_list): Fix indentation.
I think it's wrong that read_loclist_index and read_rnglist_index return
a CORE_ADDR. A CORE_ADDR is an address in the program. These functions
return offset in sections (.debug_loclists and .debug_rnglists). I
think sect_offset is more appropriate.
I'm wondering if struct attribute should have a "set_sect_offset"
method, that takes a sect_offset parameter, or if it's better to be
left as a simple "unsigned".
gdb/ChangeLog:
* dwarf2/read.c (read_loclist_index, read_rnglist_index): Return
a sect_offset.
(read_attribute_reprocess): Adjust.
Change-Id: I0e22e0864130fb490072b41ae099762918b8ad4d
Consider the test case added in this patch. It defines a compilation
unit with a DW_AT_rnglists_base attribute (used for attributes of form
DW_FORM_rnglistx), but also uses DW_AT_ranges of form
DW_FORM_sec_offset:
0x00000027: DW_TAG_compile_unit
DW_AT_ranges [DW_FORM_sec_offset] (0x0000004c
[0x0000000000005000, 0x0000000000006000))
DW_AT_rnglists_base [DW_FORM_sec_offset] (0x00000044)
The DW_AT_rnglists_base does not play a role in reading the DW_AT_ranges of
form DW_FORM_sec_offset, but it should also not do any harm.
This case is currently not handled correctly by GDB. This is not
something that a compiler is likely to emit, but in my opinion there's
no reason why GDB should fail reading it.
The problem is that in partial_die_info::read and a few other places
where the same logic is replicated, the cu->ranges_base value,
containing the DW_AT_rnglists_base value, is wrongfully added to the
DW_AT_ranges value.
It is quite messy how to decide whether cu->ranges_base should be added
to the attribute's value or not. But to summarize, the only time we
want to add it is when the attribute comes from a pre-DWARF 5 split unit
file (a .dwo) [1]. In this case, the DW_AT_ranges attribute from the
split unit file will have form DW_FORM_sec_offset, pointing somewhere in
the linked file's .debug_ranges section. *But* it's not a "true"
DW_FORM_sec_offset, in that it's an offset relative to the beginning of
that CU's contribution in the section, not relative to the beginning of
the section. So in that case, and only that case, do we want to add the
ranges base value, which we found from the DW_AT_GNU_ranges_base
attribute on the skeleton unit.
Almost all instances of the DW_AT_ranges attribute will be found in the
split unit (on DW_TAG_subprogram, for example), and therefore need to
have the ranges base added. However, the DW_TAG_compile_unit DIE in the
skeleton may also have a DW_AT_ranges attribute. For that one, the
ranges base must not be added. Once the DIEs have been loaded in GDB,
however, the distinction between what's coming from the skeleton and
what's coming from the split unit is not clear. It is all merged in one
big happy tree. So how do we know if a given attribute comes from the
split unit or not?
We use the fact that in pre-DWARF 5 split DWARF, DW_AT_ranges is found
on the skeleton's DW_TAG_compile_unit (in the linked file) and never in
the split unit's DW_TAG_compile_unit. This is why you have this in
partial_die_info::read:
int need_ranges_base = (tag != DW_TAG_compile_unit
&& attr.form != DW_FORM_rnglistx);
However, with the corner case described above (where we have a
DW_AT_rnglists_base attribute and a DW_AT_ranges attribute of form
DW_FORM_sec_offset) the condition gets it wrong when it encounters an
attribute like DW_TAG_subprogram with a DW_AT_ranges attribute of
DW_FORM_sec_offset form: it thinks that it is necessary to add the base,
when it reality it is not.
The problem boils down to failing to differentiate these cases:
- a DW_AT_ranges attribute of form DW_FORM_sec_offset in a
pre-DWARF 5 split unit (in which case we need to add the base)
- a DW_AT_ranges attribute of form DW_FORM_sec_offset in a DWARF 5
non-split unit (in which case we must not add the base)
What makes it unnecessarily complex is that the cu->ranges_base field is
overloaded, used to hold the pre-DWARF 5, non-standard
DW_AT_GNU_ranges_base and the DWARF 5 DW_AT_rnglists_base. In reality,
these two are called "bases" but are not the same thing. The result is
that we need twisted conditions to try to determine whether or not we
should add the base to the attribute's value.
To fix it, split the field in two distinct fields. I renamed everything
related to the "old" ranges base to "gnu_ranges_base", to make it clear
that it's about the non-standard, pre-DWARF 5 thing. And everything
related to the DWARF 5 thing gets renamed "rnglists". I think it
becomes much easier to reason this way.
The issue described above gets fixed by the fact that the
DW_AT_rnglists_base value does not end up in cu->gnu_ranges_base, so
cu->gnu_ranges_base stays 0. The condition to determine whether
gnu_ranges_base should be added can therefore be simplified back to:
tag != DW_TAG_compile_unit
... as it was before rnglistx support was added.
Extend the gdb.dwarf2/rnglists-sec-offset.exp to cover this case. I
also extended the test case for loclists similarly, just to see if there
would be some similar problem. There wasn't, but I think it's not a bad
idea to test that case for loclists as well, so I left it in the patch.
[1] https://gcc.gnu.org/wiki/DebugFission
gdb/ChangeLog:
* dwarf2/die.h (struct die_info) <ranges_base>: Split in...
<gnu_ranges_base>: ... this...
<rnglists_base>: ... and this.
* dwarf2/read.c (struct dwarf2_cu) <ranges_base>: Split in...
<gnu_ranges_base>: ... this...
<rnglists_base>: ... and this.
(read_cutu_die_from_dwo): Adjust
(dwarf2_get_pc_bounds): Adjust
(dwarf2_record_block_ranges): Adjust.
(read_full_die_1): Adjust
(partial_die_info::read): Adjust.
(read_rnglist_index): Adjust.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/rnglists-sec-offset.exp: Add test for DW_AT_ranges
of DW_FORM_sec_offset form plus DW_AT_rnglists_base attribute.
* gdb.dwarf2/loclists-sec-offset.exp: Add test for
DW_AT_location of DW_FORM_sec_offset plus DW_AT_loclists_base
attribute
Change-Id: Icd109038634b75d0e6e9d7d1dcb62fb9eb951d83
When loading the binary from PR 26813 in GDB, we get:
DW_FORM_rnglistx index pointing outside of .debug_rnglists offset array [in module /home/simark/build/binutils-gdb/gdb/MagicPurse]
... and the symbols fail to load.
In read_rnglist_index and read_loclist_index, we read the header
(documented in sections 7.28 and 7.29 of DWARF 5) of the CU's
contribution to the .debug_rnglists / .debug_loclists sections to
validate that the index we want to read makes sense. However, we always
read the header at the beginning of the section, rather than the header
for the contribution from which we want to read the index.
To illustrate, here's what the binary from PR 26813 contains. There are
two compile units:
0x0000000c: DW_TAG_compile_unit 1
DW_AT_ranges [DW_FORM_rnglistx]: 0x0
DW_AT_rnglists_base [DW_FORM_sec_offset]: 0xC
0x00003ec9: DW_TAG_compile_unit 2
DW_AT_ranges [DW_FORM_rnglistx]: 0xB
DW_AT_rnglists_base [DW_FORM_sec_offset]: 0x85
The layout of the .debug_rnglists is the following:
[0x00, 0x0B]: header for CU 1's contribution
[0x0C, 0x0F]: list of offsets for CU 1 (1 element)
[0x10, 0x78]: range lists data for CU 1
[0x79, 0x84]: header for CU 2's contribution
[0x85, 0xB4]: list of offsets for CU 2 (12 elements)
[0xB5, 0xBD7]: range lists data for CU 2
The DW_AT_rnglists_base attrbute points to the beginning of the list of
offsets for that CU, relative to the start of the .debug_rnglists
section. That's right after the header for that contribution.
When we try to read the DW_AT_ranges attribute for CU 2,
read_rnglist_index reads the header for CU 1 instead of the one for CU
2. Since there's only one element in CU 1's offset list, it believes
(wrongfully) that the index 0xB is out of range.
Fix it by reading the header just before where DW_AT_rnglists_base
points to. With this patch, I am able to load GDB built with clang-11
and -gdwarf-5 in itself, with and without -readnow.
gdb/ChangeLog:
PR gdb/26813
* dwarf2/read.c (read_loclists_rnglists_header): Add
header_offset parameter and use it.
(read_loclist_index): Read header of the current contribution,
not the one at the beginning of the section.
(read_rnglist_index): Likewise.
Change-Id: Ie53ff8251af8c1556f0a83a31aa8572044b79e3d
We hit an assertion when loading the binary from PR 26813. When fixing
it, execution goes a up bit further but then hits another assert, and
another, and another. With these fours fixes, I am able to load the
binary and get to the prompt. An error is shown (index pointing outside
of the section), because the DW_FORM_rnglistx attribute is not read
correctly, but that one is taken care of by the next patch.
The four fixes are:
- attribute::form_requires_reprocessing needs to handle forms
DW_FORM_rnglistx and DW_FORM_loclistx, because set_unsigned_reprocess
is called for them in read_attribute_value.
- read_attribute_reprocess must call set_unsigned for them, not
set_address. The parameter of set_address is a CORE_ADDR, meaning
it's for program addresses. Post-reprocess, DW_FORM_rnglistx and
DW_FORM_loclistx are offsets into their respective sections
(.debug_rnglists and .debug_loclists). set_unsigned is the current
attribute value setter that fits the best. But perhaps we should have
a setter that takes a sect_offset?
- read_attribute_process must call as_unsigned_reprocess instead of
as_unsigned to get the pre-reprocess value, otherwise we hit the
assert inside as_unsigned that makes sure the attribute doesn't need
reprocessing.
- attribute::set_unsigned needs to clear the requires_reprocessing flag,
otherwise it stays set when reprocessing DW_FORM_rnglistx and
DW_FORM_loclistx attributes.
There's another assert that we hit once the next patch is applied, but
since it's in the same vein as the changes in this patch, I included it
in this patch:
- attribute::form_is_unsigned must handle form DW_FORM_loclistx,
otherwise we hit the assert when trying to call set_unsigned for an
attribute of this form. DW_FORM_rnglistx is already handled.
gdb/ChangeLog:
PR gdb/26813
* dwarf2/attribute.h (struct attribute) <set_unsigned>: Clear
requires_reprocessing flag.
* dwarf2/attribute.c (attribute::form_is_unsigned): Handle
DW_FORM_loclistx.
(attribute::form_requires_reprocessing): Handle DW_FORM_rnglistx
and DW_FORM_loclistx.
* dwarf2/read.c (read_attribute_reprocess): Use set_unsigned
instead of set_address for DW_FORM_loclistx and
DW_FORM_rnglistx.
Change-Id: I06c156fa3913ca98e4e39085f4ef171645b4bc1e
In read_rnglist_index and read_loclist_index, we check that both the
start and end of the offset that we read from the offset table are
within the section. I think it's unecessary to do both: if the end of
the offset is within the section, then surely the start of the offset is
within it.
Remove the check for the start of the offset in both functions.
gdb/ChangeLog:
* dwarf2/read.c (read_loclist_index): Remove bound check for
start of offset.
(read_rnglist_index): Likewise.
Change-Id: I7b57ddf4f8a8a28971738f0e3f3af62108f9e19a
read_rnglist_index has a bound check to make sure that we don't go past
the end of the section while reading the offset, but read_loclist_index
doesn't. Add it to read_loclist_index.
gdb/ChangeLog:
* dwarf2/read.c (read_loclist_index): Add bound check for the end
of the offset.
Change-Id: Ic4b55c88860fdc3e007740949c78ec84cdb4da60
I think this check in read_rnglist_index is wrong:
/* Validate that reading won't go beyond the end of the section. */
if (start_offset + cu->header.offset_size > rnglist_base + section->size)
error (_("Reading DW_FORM_rnglistx index beyond end of"
".debug_rnglists section [in module %s]"),
objfile_name (objfile));
The addition `rnglist_base + section->size` doesn't make sense.
rnglist_base is an offset into `section`, so it doesn't make sense to
add it to `section`'s size. `start_offset` also is an offset into
`section`, so we should just compare it to just `section->size`.
gdb/ChangeLog:
* dwarf2/read.c (read_rnglist_index): Fix bound check.
Change-Id: If0ff7c73f4f80f79aac447518f4e8f131f2db8f2
Unlike read_rnglists_index, read_loclist_index uses complaints when it
detects an inconsistency (a DW_FORM_loclistx value without a
.debug_loclists section or an offset outside of the section). I really
think they should be errors, since there's no point in continuing if
this situation happens, we will likely segfault or read garbage.
gdb/ChangeLog:
* dwarf2/read.c (read_loclist_index): Change complaints into
errors.
Change-Id: Ic3a1cf6e682d47cb6e739dd76fd7ca5be2637e10
While looking into a failure in gdb.go/package.exp with gcc-11, I noticed that
gdb shows some complaints when loading the executable (also with gcc-10, where
the test-case passes):
...
$ gdb -batch -iex "set complaints 100" package.10 -ex start
During symbol reading: Attribute value is not a constant (DW_FORM_sec_offset)
Temporary breakpoint 1 at 0x402ae6: file gdb.go/package1.go, line 8.
During symbol reading: Attribute value is not a constant (DW_FORM_sec_offset)
During symbol reading: Invalid .debug_rnglists data (no base address)
...
Fix this by using as_unsigned () to read DW_AT_ranges in the partial DIE
reader, similar to how that is done in dwarf2_get_pc_bounds.
Tested on x86_64-linux.
gdb/ChangeLog:
2021-01-25 Bernd Edlinger <bernd.edlinger@hotmail.de>
Simon Marchi <simon.marchi@polymtl.ca>
Tom de Vries <tdevries@suse.de>
* dwarf2/read.c (partial_die_info::read): Use as_unsigned () for
DW_AT_ranges.
gdb/testsuite/ChangeLog:
2021-01-25 Tom de Vries <tdevries@suse.de>
* gdb.dwarf2/dw2-ranges-psym.exp (gdb_load_no_complaints): New proc.
* lib/gdb.exp: Use gdb_load_no_complaints.
A recent version of GCC changed how fixed-point types are described.
For example, a denominator in one test case now looks like:
GNU_denominator (exprloc)
[ 0] implicit_value: 16 byte block: 00 00 b8 9d 0d 69 55 a0 01 00 00 00 00 00 00 00
... the difference being that this now uses exprloc and emits a
DW_OP_implicit_value for the 16-byte block. (DWARF 5 still uses
DW_FORM_data16.)
This change was made here:
https://gcc.gnu.org/pipermail/gcc-patches/2020-December/560897.html
This patch updates gdb to handle this situation.
Note that, before GCC 11, this test would not give the same answer.
Earlier versions of GCC fell back to GNAT encodings for this case.
gdb/ChangeLog
2021-01-25 Tom Tromey <tromey@adacore.com>
* dwarf2/read.c (get_mpz): New function.
(get_dwarf2_rational_constant): Use it.
gdb/testsuite/ChangeLog
2021-01-25 Tom Tromey <tromey@adacore.com>
* gdb.ada/fixed_points.exp: Add regression test.
* gdb.ada/fixed_points/fixed_points.adb (FP5_Var): New variable.
* gdb.ada/fixed_points/pck.adb (Delta5, FP5_Type): New.
The symptom that leads to this is the crash described in PR 26828:
/home/simark/src/binutils-gdb/gdb/dwarf2/read.c:23478:25: runtime error: member access within null pointer of type 'struct dwarf2_cu'
The line of the crash is the following, in follow_die_offset:
if (target_cu != cu)
target_cu->ancestor = cu; <--- HERE
The line that assign nullptr to `target_cu` is the `per_objfile->get_cu`
call after having called maybe_queue_comp_unit:
/* If necessary, add it to the queue and load its DIEs. */
if (maybe_queue_comp_unit (cu, per_cu, per_objfile, cu->language))
load_full_comp_unit (per_cu, per_objfile, per_objfile->get_cu (per_cu),
false, cu->language);
target_cu = per_objfile->get_cu (per_cu); <--- HERE
Some background: there is an invariant, documented in
maybe_queue_comp_unit's doc, that if a CU is queued for expansion
(present in dwarf2_per_bfd::queue), then its DIEs are loaded in memory.
"its DIEs are loaded in memory" is a synonym for saying that a dwarf2_cu
object exists for this CU. Yet another way to say it is that
`per_objfile->get_cu (per_cu)` returns something not nullptr for that
CU.
The crash documented in PR 26828 triggers some hard-to-reproduce
sequence that ends up violating the invariant:
- dwarf2_fetch_die_type_sect_off gets called for a DIE in CU A
- The DIE in CU A requires some DIE in CU B
- follow_die_offset calls maybe_queue_comp_unit. maybe_queue_comp_unit
sees CU B is not queued and its DIEs are not loaded, so it enqueues it
and returns 1 to its caller - meaning "the DIEs are not loaded, you
should load them" - prompting follow_die_offset to load the DIEs by
calling load_full_comp_unit
- Note that CU B is enqueued by maybe_queue_comp_unit even if it has
already been expanded. It's a bit useless (and causes trouble, see
next patch), but that's how it works right now.
- Since we entered the dwarf2/read code through
dwarf2_fetch_die_type_sect_off, nothing processes the queue, so we
exit the dwarf2/read code with CU B still lingering in the queue.
- dwarf2_fetch_die_type_sect_off gets called for a DIE in CU A, again
- The DIE in CU A requires some DIE in CU B, again
- This time, maybe_queue_comp_unit sees that CU B is in the queue.
Because of the invariant that if a CU is in the queue, its DIEs are
loaded in the memory, it returns 0 to its caller, meaning "you don't
need to load the DIEs!".
- That happens to be true, so everything is fine for now.
- Time passes, some things call dwarf2_per_objfile::age_comp_units
enough so that CU B's age becomes past the dwarf_max_cache_age
threshold. age_comp_units proceeds to free CU B's DIEs. Remember
that CU B is still lingering in the queue (oops, the invariant just
got violated).
- dwarf2_fetch_die_type_sect_off gets called for a DIE in CU A, again
- The DIE in CU A requires some DIE in CU B, again
- maybe_queue_comp_unit sees that CU B is in the queue, so returns to
its caller "you don't need to load the DIEs!". However, we know at
this point this is false.
- follow_die_offset doesn't load the DIEs and tries to obtain the DIEs for
CU B:
target_cu = per_objfile->get_cu (per_cu);
But since they are not loaded, target_cu is nullptr, and we get the
crash mentioned above a few lines after that.
This patch adds an assertions in maybe_queue_comp_unit to verify the
invariant, to make sure it doesn't return a falsehood to its caller.
The current patch doesn't fix the issue (the next patch does), but it
makes it so we catch the problem earlier and get this assertion failure
instead of a segmentation fault:
/home/simark/src/binutils-gdb/gdb/dwarf2/read.c:9100: internal-error:
int maybe_queue_comp_unit(dwarf2_cu*, dwarf2_per_cu_data*, dwarf2_per_objfile*, language):
Assertion `per_objfile->get_cu (per_cu) != nullptr' failed.
gdb/ChangeLog:
PR gdb/26828
* dwarf2/read.c (maybe_queue_comp_unit): Add assertion.
Change-Id: I4e51bd7bd58773f9fadf480179cbc4bae61508fe
This patch adds some logging that helped me diagnose the problems fixed
later in this series. I'm thinking that if it helped me now, it could
help somebody else (or myself) in the future, so I might as well add
them for real.
They can happen quite frequently and be noisy, so I used
dwarf_read_debug_printf_v for them, which means they'll only print if
`set debug dwarf-read` is >= 2.
gdb/ChangeLog:
* dwarf2/read.c (follow_die_offset): Add logging.
(dwarf2_per_objfile::age_comp_units): Add logging.
Change-Id: I7483c0b05c37bc9710b9b5d40e272935bc010863
This commits the result of running gdb/copyright.py as per our Start
of New Year procedure...
gdb/ChangeLog
Update copyright year range in copyright header of all GDB files.
The function c_printchar is called from two places; it provides the
implementation of language_defn::printchar and it is called from
dwarf2_compute_name.
It would be nice to rename c_printchar as language_defn::printchar and
so avoid the trampoline.
To achieve this, instead of calling c_printchar directly from the
DWARF code, I lookup the C++ language object and call the printchar
member function.
In a later commit I can then rename c_printchar.
There should be no user visible changes after this commit.
gdb/ChangeLog:
* dwarf2/read.c (dwarf2_compute_name): Call methods on C++
language object instead of calling global functions directly.
To handle thick pointers with -fgnat-encodings=minimal, gdb will
rewrite the underlying array type to remove the bounds. However, if
the same DWARF type is used both for a thick pointer and for an
ordinary array, this will have the side effect of removing the bounds
from the array. This breaks the printing of objects of this type.
This patch fixes the problem by copying the array type, its range, and
its bounds.
gdb/ChangeLog
2020-12-14 Tom Tromey <tromey@adacore.com>
* dwarf2/read.c (rewrite_array_type): New function.
(quirk_ada_thick_pointer_struct): Use rewrite_array_type.
gdb/testsuite/ChangeLog
2020-12-14 Tom Tromey <tromey@adacore.com>
* gdb.dwarf2/ada-thick-pointer.exp: New file.
The same pattern happens often to define a "debug_printf" macro:
#define displaced_debug_printf(fmt, ...) \
do \
{ \
if (debug_displaced) \
debug_prefixed_printf ("displaced", __func__, fmt, ##__VA_ARGS__); \
} \
while (0)
Move this pattern behind a helper macro, debug_prefixed_printf_cond and
update the existing macros to use it.
gdb/ChangeLog:
* displaced-stepping.h (displaced_debug_printf): Use
debug_prefixed_printf_cond.
* dwarf2/read.c (dwarf_read_debug_printf): Likewise.
(dwarf_read_debug_printf_v): Likewise.
* infrun.h (infrun_debug_printf): Likewise.
* linux-nat.c (linux_nat_debug_printf): Likewise.
gdbsupport/ChangeLog:
* common-debug.h (debug_prefixed_printf_cond): New.
* event-loop.h (event_loop_debug_printf): Use
debug_prefixed_printf_cond.
Change-Id: I1ff48b98b8d1cc405d1c7e8da8ceadf4e3a17f99
In some cases, GNAT can emit 128-bit constants for fixed-point types.
This patch changes gdb to handle this scenario, by changing the
low-level rational-reading functions in dwarf2/read.c to work directly
with gdb_mpz values. (I'm not sure offhand if these 128-bit patches
have gone into upstream GCC yet -- but they will eventually, and
meanwhile I think it should be clear that this patch is otherwise
harmless.)
gdb/ChangeLog
2020-12-09 Tom Tromey <tromey@adacore.com>
* dwarf2/read.c (get_dwarf2_rational_constant): Change "numerator"
and "denominator" to gdb_mpz. Handle block forms.
(get_dwarf2_unsigned_rational_constant): Change "numerator" and
"denominator" to gdb_mpz.
(finish_fixed_point_type): Update.
(has_zero_over_zero_small_attribute): Update.
When Debian (and Ubuntu) builds its binaries, it (still) doesn't use
dwz's "--relative" option. This causes their debuginfo files to
carry a .gnu_debugaltlink section containing a full pathname to the
DWZ alt debug file, like this:
$ readelf -wk /usr/bin/cat
Contents of the .gnu_debugaltlink section:
Separate debug info file: /usr/lib/debug/.dwz/x86_64-linux-gnu/coreutils.debug
Build-ID (0x14 bytes):
ee 76 5d 71 97 37 ce 46 99 44 32 bb e8 a9 1a ef 99 96 88 db
Contents of the .gnu_debuglink section:
Separate debug info file: 06d3bee37b8c7e67b31cb2689cb351102ae73b.debug
CRC value: 0x53267655
This usually works OK, because most of the debuginfo files installed
via apt will be present in /usr/lib/debug anyway. However, imagine
the following scenario:
- You are using /usr/bin/cat, it crashes on you and generates a
corefile.
- You don't want/need to "apt install" the debuginfo file for
coreutils from the repositories. Instead, you already have the
debuginfo files in a separate directory (e.g., $HOME/dbgsym).
- You start GDB and "set debug-file-directory $HOME/dbgsym/usr/lib/debug".
You then get the following message:
$ gdb -ex 'set debug-file-directory ./dbgsym/usr/lib/debug' -ex 'file /bin/cat' -ex 'core-file ./cat.core'
GNU gdb (Ubuntu 10.1-0ubuntu1) 10.1
...
Reading symbols from /bin/cat...
Reading symbols from /home/sergio/gdb/dbgsym/usr/lib/debug/.build-id/bc/06d3bee37b8c7e67b31cb2689cb351102ae73b.debug...
could not find '.gnu_debugaltlink' file for /home/sergio/gdb/dbgsym/usr/lib/debug/.build-id/bc/06d3bee37b8c7e67b31cb2689cb351102ae73b.debug
This error happens because GDB is trying to locate the build-id
link (inside /home/sergio/gdb/dbgsym/usr/lib/debug/.build-id) for the
DWZ alt debug file, which doesn't exist. Arguably, this is a problem
with how dh_dwz works in Debian, and it's something I'm also planning
to tackle. But, back at the problem at hand.
Besides not being able to find the build-id link in the directory
mentioned above, GDB also tried to open the DWZ alt file using its
filename. The problem here is that, since we don't have the distro's
debuginfo installed, it can't find anything under /usr/lib/debug that
satisfies it.
It occurred to me that a good way to workaround this problem is to
actually try to locate the DWZ alt debug file inside the
debug-file-directories (that were likely provided by the user). So
this is what the proposed patch does.
The idea here is simple: get the filename extracted from the
.gnu_debugaltlink section, and manipulate it in order to replace the
initial part of the path (everything before "/.dwz/") by whatever
debug-file-directories the user might have provided.
I talked with Mark Wielaard and he agrees this is a sensible approach.
In fact, apparently this is something that eu-readelf also does.
I regtested this code, and no regressions were found.
2020-12-01 Sergio Durigan Junior <sergiodj@sergiodj.net>
* dwarf2/read.c (dwz_search_other_debugdirs): New function.
(dwarf2_get_dwz_file): Convert 'filename' to a
std::string. Use dwz_search_other_debugdirs to search for DWZ
files in the debug-file-directories provided by the user as well.
This is one step further towards the removal of all these macros.
gdb/ChangeLog:
* gdbtypes.h (struct type) <fixed_point_info, set_fixed_point_info>:
New methods.
(INIT_FIXED_POINT_SPECIFIC): Adjust.
(TYPE_FIXED_POINT_INFO): Delete macro.
(allocate_fixed_point_type_info): Change return type to void.
* gdbtypes.c (copy_type_recursive): Replace the use of
TYPE_FIXED_POINT_INFO by a call to the fixed_point_info method.
(fixed_point_scaling_factor): Likewise.
(allocate_fixed_point_type_info): Change return type to void.
Adjust implementation accordingly.
* dwarf2/read.c (finish_fixed_point_type): Replace the use of
TYPE_FIXED_POINT_INFO by a call to the fixed_point_info method.
When building on solaris (gcc farm machine gcc211), I get:
CXX dwarf2/read.o
/export/home/simark/src/binutils-gdb/gdb/dwarf2/read.c: In function 'void finish_fixed_point_type(type*, die_info*, dwarf2_cu*)':
/export/home/simark/src/binutils-gdb/gdb/dwarf2/read.c:18204:42: error: call of overloaded 'abs(LONGEST&)' is ambiguous
*num_or_denom = 1 << abs (scale_exp);
^
In file included from /usr/include/stdlib.h:11:0,
from ../gnulib/import/stdlib.h:36,
from /opt/csw/include/c++/5.5.0/cstdlib:72,
from /export/home/simark/src/binutils-gdb/gdb/../gdbsupport/common-defs.h:90,
from /export/home/simark/src/binutils-gdb/gdb/defs.h:28,
from /export/home/simark/src/binutils-gdb/gdb/dwarf2/read.c:31:
/opt/csw/lib/gcc/sparc-sun-solaris2.10/5.5.0/include-fixed/iso/stdlib_iso.h:163:16: note: candidate: long int std::abs(long int)
inline long abs(long _l) { return labs(_l); }
^
/opt/csw/lib/gcc/sparc-sun-solaris2.10/5.5.0/include-fixed/iso/stdlib_iso.h:117:12: note: candidate: int std::abs(int)
extern int abs(int);
^
I don't know why, but using std::abs instead of just abs fixes it.
gdb/ChangeLog:
* dwarf2/read.c (finish_fixed_point_type): Use std::abs instead
of abs.
Change-Id: I57b9098351f2a8b2d2f61e848b97f7b2dfe55908
This commit introduces a new kind of type, meant to describe
fixed-point types, using a new code added specifically for
this purpose (TYPE_CODE_FIXED_POINT).
It then adds handling of fixed-point base types in the DWARF reader.
And finally, as a first step, this commit adds support for printing
the value of fixed-point type objects.
Note that this commit has a known issue: Trying to print the value
of a fixed-point object with a format letter (e.g. "print /x NAME")
causes the wrong value to be printed because the scaling factor
is not applied. Since the fix for this issue is isolated, and
this is not a regression, the fix will be made in a pach of its own.
This is meant to simplify review and archeology.
Also, other functionalities related to fixed-point type handling
(ptype, arithmetics, etc), will be added piecemeal as well, for
the same reasons (faciliate reviews and archeology). Related to this,
the testcase gdb.ada/fixed_cmp.exp is adjusted to compile the test
program with -fgnat-encodings=all, so as to force the use of GNAT
encodings, rather than rely on the compiler's default to use them.
The intent is to enhance this testcase to also test the pure DWARF
approach using -fgnat-encodings=minimal as soon as the corresponding
suport gets added in. Thus, the modification to the testcase is made
in a way that it prepares this testcase to be tested in both modes.
gdb/ChangeLog:
* ada-valprint.c (ada_value_print_1): Add fixed-point type handling.
* dwarf2/read.c (get_dwarf2_rational_constant)
(get_dwarf2_unsigned_rational_constant, finish_fixed_point_type)
(has_zero_over_zero_small_attribute): New functions.
read_base_type, set_die_type): Add fixed-point type handling.
* gdb-gdb.py.in: Add fixed-point type handling.
* gdbtypes.c: #include "gmp-utils.h".
(create_range_type, set_type_code): Add fixed-point type handling.
(init_fixed_point_type): New function.
(is_integral_type, is_scalar_type): Add fixed-point type handling.
(print_fixed_point_type_info): New function.
(recursive_dump_type, copy_type_recursive): Add fixed-point type
handling.
(fixed_point_type_storage): New typedef.
(fixed_point_objfile_key): New static global.
(allocate_fixed_point_type_info, is_fixed_point_type): New functions.
(fixed_point_type_base_type, fixed_point_scaling_factor): New
functions.
* gdbtypes.h: #include "gmp-utils.h".
(enum type_code) <TYPE_SPECIFIC_FIXED_POINT>: New enum.
(union type_specific) <fixed_point_info>: New field.
(struct fixed_point_type_info): New struct.
(INIT_FIXED_POINT_SPECIFIC, TYPE_FIXED_POINT_INFO): New macros.
(init_fixed_point_type, is_fixed_point_type)
(fixed_point_type_base_type, fixed_point_scaling_factor)
(allocate_fixed_point_type_info): Add declarations.
* valprint.c (generic_val_print_fixed_point): New function.
(generic_value_print): Add fixed-point type handling.
* value.c (value_as_address, unpack_long): Add fixed-point type
handling.
gdb/testsuite/ChangeLog:
* gdb.ada/fixed_cmp.exp: Force compilation to use -fgnat-encodings=all.
* gdb.ada/fixed_points.exp: Add fixed-point variables printing tests.
* gdb.ada/fixed_points/pck.ads, gdb.ada/fixed_points/pck.adb:
New files.
* gdb.ada/fixed_points/fixed_points.adb: Add use of package Pck.
* gdb.dwarf2/dw2-fixed-point.c, gdb.dwarf2/dw2-fixed-point.exp:
New files.
It took me a while to understand why that would even compile: it looks
like we pass a type name as a pointer, that makes no sense. By looking
at the DWARF, I understood that the compiler actually interprets it as a
function declaration. So the statement was doing nothing, no
dwarf2_queue_guard was instantiated. Fix it by passing the right
variable name.
gdb/ChangeLog:
* dwarf2/read.c (dw2_do_instantiate_symtab): Fix call to
dwarf2_queue_guard.
Change-Id: I3a7bdead9e8c39f8342a471f10181b85b8f0d801
Add dwarf_read_debug_printf and dwarf_read_debug_printf_v macros and use
them throughout dwarf2/read.c. The second one is used for "verbose"
prints, when the value of "set debug dwarf-read" is >= 2.
gdb/ChangeLog:
* dwarf2/read.c (dwarf_read_debug_printf,
dwarf_read_debug_printf_v): New macros, use throughout the file.
Change-Id: I694da69da2e1f2caa4c27a421a975790636411e2
In a longer series that I am working on, I needed to remove the
objfile parameter from abbrev_table::read. It seemed to me that this
was a simple and relatively harmless patch, so I'm sending it now.
gdb/ChangeLog
2020-11-05 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (read_cutu_die_from_dwo)
(cutu_reader::cutu_reader, cutu_reader::cutu_reader)
(build_type_psymtabs_1): Update.
* dwarf2/abbrev.h (struct abbrev_table): Remove objfile
parameter.
* dwarf2/abbrev.c (abbrev_table::read): Remove objfile parameter.
Don't read section. Add assert.
With -fgnat-encodings=minimal, Gnat will emit DW_TAG_array_type that
has a name -- and this is the only time the name is emitted for the
type. (For comparison, in C a typedef would be emitted in this
situation.)
This patch changes gdb to recognize the name of an array type. This
is limited to Ada, to avoid any potential problems if some rogue DWARF
happens to name an array type in some other language, and to avoid
loading unnecessary partial DIEs.
gdb/ChangeLog
2020-11-04 Tom Tromey <tromey@adacore.com>
* dwarf2/read.c (add_partial_symbol, process_die):
Handle DW_TAG_array_type.
(is_type_tag_for_partial): Add "lang" parameter.
(load_partial_dies, new_symbol): Handle DW_TAG_array_type.
gdb/testsuite/ChangeLog
2020-11-04 Tom Tromey <tromey@adacore.com>
* gdb.ada/tick_length_array_enum_idx.exp: Add ptype test.
* gdb.ada/tick_length_array_enum_idx/foo_n207_004.adb
(PT_Full): New variable.
* gdb.ada/tick_length_array_enum_idx/pck.adb
(Full_PT): New type.
A DWARF array type may specify a stride. Currently, the DWARF reader
applies this stride to every dimension of an array. However, this
seems incorrect to me -- only the innermost array ought to use the
stride, while outer arrays should compute a stride based on the size
of the inner arrays. This patch arranges to apply the stride only to
the innermost array type. This fixes a bug noticed when running some
Ada tests with -fgnat-encodings=minimal.
gdb/ChangeLog
2020-11-04 Tom Tromey <tromey@adacore.com>
* dwarf2/read.c (read_array_type): Only apply stride to innermost
array.
gdb/testsuite/ChangeLog
2020-11-04 Tom Tromey <tromey@adacore.com>
* gdb.ada/enum_idx_packed.exp: Add test.
* gdb.ada/enum_idx_packed/foo.adb (Multi_Access):
New variable.
* gdb.ada/enum_idx_packed/pck.ads (Short)
(Multi_Dimension, Multi_Dimension_Access): New types.
When -fgnat-encodings=minimal, the compiler will avoid the special
GNAT-specific "encodings" format, and instead emit ordinary DWARF as
much as possible.
When emitting DWARF for thick pointers to arrays, the compiler emits
something like:
<1><11db>: Abbrev Number: 7 (DW_TAG_array_type)
<11dc> DW_AT_name : (indirect string, offset: 0x1bb8): string
<11e0> DW_AT_data_location: 2 byte block: 97 6
(DW_OP_push_object_address; DW_OP_deref)
<11e3> DW_AT_type : <0x1173>
<11e7> DW_AT_sibling : <0x1201>
<2><11eb>: Abbrev Number: 8 (DW_TAG_subrange_type)
<11ec> DW_AT_type : <0x1206>
<11f0> DW_AT_lower_bound : 6 byte block: 97 23 8 6 94 4
(DW_OP_push_object_address; DW_OP_plus_uconst: 8; DW_OP_deref;
DW_OP_deref_size: 4)
<11f7> DW_AT_upper_bound : 8 byte block: 97 23 8 6 23 4 94 4
(DW_OP_push_object_address; DW_OP_plus_uconst: 8; DW_OP_deref;
DW_OP_plus_uconst: 4; DW_OP_deref_size: 4)
If you read between the lines, the "array" is actually a structure
with two elements. One element is a pointer to the array data, and
the other structure describes the bounds of the array. However, the
compiler doesn't emit this explicitly, but instead hides it behind
these location expressions.
gdb can print such objects, but currently there is no way to construct
one. So, this patch adds some code to the DWARF reader to recognize
this construct, and then synthesize an array descriptor. This
descriptor is then handled by the existing Ada code.
Internally, we've modified GCC to emit the structure type explicitly
(we will of course be sending this upstream). In this case, the array
still has the DW_AT_data_location, though. This patch also modifies
gdb to ignore the data location in this case -- this is preferred
because the location only serves to confuse the Ada code that already
knows where to find the data. In the future I hope to move some of
this handling to the gdb core, so that Ada-specific hacks are not
needed; however I have not yet done this.
Because parallel types are not emitted with -fgnat-encodings=minimal,
some changes to the Ada code were also required.
The change ina ada-valprint.c was needed to avoid infinite recursion
when trying to print a constrained packed array. And, there didn't
seem to be any need for a recursive call here -- the value could
simply be returned instead.
Finally, gdb.ada/frame_arg_lang.exp no longer works in C mode, because
we drop back to the structure approach now. As mentioned earlier,
future work should probably fix this again; meanwhile, this doesn't
seem to be a big problem, because it is what is currently done (users
as a rule don't use -fgnat-encodings=minimal -- which is what I am
ultimately trying to fix).
Note that a couple of tests have an added KFAIL. Some
-fgnat-encodings=minimal changes have landed in GNAT, and you need
something very recent to pass all the tests. I'm using git gcc to
accomplish this.
gdb/ChangeLog
2020-11-04 Tom Tromey <tromey@adacore.com>
* dwarf2/read.c (recognize_bound_expression)
(quirk_ada_thick_pointer): New functions.
(read_array_type): Call quirk_ada_thick_pointer.
(set_die_type): Add "skip_data_location" parameter.
(quirk_ada_thick_pointer): New function.
(process_structure_scope): Call quirk_ada_thick_pointer.
* ada-lang.c (ada_is_unconstrained_packed_array_type)
(decode_packed_array_bitsize): Handle thick pointers without
parallel types.
(ada_is_gnat_encoded_packed_array_type): Rename from
ada_is_packed_array_type.
(ada_is_constrained_packed_array_type): Update.
* ada-valprint.c (ada_val_print_gnat_array): Remove.
(ada_value_print_1): Use ada_get_decoded_value.
gdb/testsuite/ChangeLog
2020-11-04 Tom Tromey <tromey@adacore.com>
* gdb.ada/O2_float_param.exp: Test different -fgnat-encodings
values.
* gdb.ada/access_to_unbounded_array.exp: Test different
-fgnat-encodings values.
* gdb.ada/big_packed_array.exp: Test different -fgnat-encodings
values.
* gdb.ada/arr_enum_idx_w_gap.exp: Test different -fgnat-encodings
values.
* gdb.ada/array_ptr_renaming.exp: Test different -fgnat-encodings
values.
* gdb.ada/array_of_variable_length.exp: Test different
-fgnat-encodings values.
* gdb.ada/arrayparam.exp: Test different -fgnat-encodings values.
* gdb.ada/arrayptr.exp: Test different -fgnat-encodings values.
* gdb.ada/frame_arg_lang.exp: Revert -fgnat-encodings=minimal
change.
* gdb.ada/mi_string_access.exp: Test different -fgnat-encodings
values.
* gdb.ada/mod_from_name.exp: Test different -fgnat-encodings values.
* gdb.ada/out_of_line_in_inlined.exp: Test different
-fgnat-encodings values.
* gdb.ada/packed_array.exp: Test different -fgnat-encodings
values.
* gdb.ada/pckd_arr_ren.exp: Test different -fgnat-encodings
values.
* gdb.ada/unc_arr_ptr_in_var_rec.exp: Test different
-fgnat-encodings values.
* gdb.ada/variant_record_packed_array.exp: Test different
-fgnat-encodings values.
This changes end_psymtab_common to be a method on partial_symtab.
This seems a little cleaner to me.
gdb/ChangeLog
2020-11-01 Tom Tromey <tom@tromey.com>
* dbxread.c (dbx_end_psymtab): Update.
* dwarf2/read.c (process_psymtab_comp_unit_reader)
(build_type_psymtabs_reader): Update.
* xcoffread.c (xcoff_end_psymtab): Update.
* ctfread.c (scan_partial_symbols): Update.
* psymtab.c (sort_pst_symbols): Remove.
(partial_symtab::end): Rename from end_psymtab_common. Inline
sort_pst_symbols.
* psympriv.h (struct partial_symtab) <end>: New method.
(end_psymtab_common): Don't declare.
init_psymbol_list is now empty, and so this removes it.
gdb/ChangeLog
2020-11-01 Tom Tromey <tom@tromey.com>
* dbxread.c (dbx_symfile_read): Update.
* dwarf2/read.c (dwarf2_build_psymtabs): Update.
* xcoffread.c (xcoff_initial_scan): Update.
* psympriv.h (init_psymbol_list): Don't declare.
* psymtab.c (init_psymbol_list): Remove.
Consider the test-case contained in this patch. It consists of
two CUs:
- cu1, containing a DW_TAG_variable DIE foo
- cu2, containing a DW_TAG_base_type DIE int
where the variable foo has type int, in other words, there's an inter-CU
reference.
When expanding the symtab for cu1, expansion of the symtab for cu2 is
enqueued, and later processed by process_full_comp_unit. However, processing
of .debug_ranges fails because the range is specified relative to a base
address which is considered not to be present because
!cu->base_address.has_value (), and we run into this case in
dwarf2_ranges_process:
...
if (!base.has_value ())
{
/* We have no valid base address for the ranges
data. */
complaint (_("Invalid .debug_ranges data (no base address)"));
return 0;
}
...
Fix this in process_full_comp_unit by setting cu->base_address.
Tested on x86_64-linux.
gdb/ChangeLog:
2020-10-26 Tom de Vries <tdevries@suse.de>
* dwarf2/read.c (process_full_comp_unit): Call
dwarf2_find_base_address.
gdb/testsuite/ChangeLog:
2020-10-26 Tom de Vries <tdevries@suse.de>
* gdb.dwarf2/enqueued-cu-base-addr.exp: New file.
Fix a regression introduced by commit 7188ed02d2 ("Replace
dwarf2_per_cu_data::cu backlink with per-objfile map").
This patch targets both master and gdb-10-branch, since this is a
regression from GDB 9.
Analysis
--------
The DWARF generated by the included test case looks like:
0x0000000b: DW_TAG_compile_unit
DW_AT_language [DW_FORM_sdata] (4)
0x0000000d: DW_TAG_base_type
DW_AT_name [DW_FORM_string] ("int")
DW_AT_byte_size [DW_FORM_data1] (0x04)
DW_AT_encoding [DW_FORM_sdata] (5)
0x00000014: DW_TAG_subprogram
DW_AT_name [DW_FORM_string] ("apply")
0x0000001b: DW_TAG_subprogram
DW_AT_specification [DW_FORM_ref4] (0x00000014 "apply")
DW_AT_low_pc [DW_FORM_addr] (0x0000000000001234)
DW_AT_high_pc [DW_FORM_data8] (0x0000000000000020)
0x00000030: DW_TAG_template_type_parameter
DW_AT_name [DW_FORM_string] ("T")
DW_AT_type [DW_FORM_ref4] (0x0000000d "int")
0x00000037: NULL
0x00000038: NULL
Simply loading the file in GDB makes it crash:
$ ./gdb -nx --data-directory=data-directory testsuite/outputs/gdb.dwarf2/pr26693/pr26693
[1] 15188 abort (core dumped) ./gdb -nx --data-directory=data-directory
The crash happens here, where htab (a dwarf2_cu::die_hash field) is
unexpectedly NULL while generating partial symbols:
#0 0x000055555fa28188 in htab_find_with_hash (htab=0x0, element=0x7fffffffbfa0, hash=27) at /home/simark/src/binutils-gdb/libiberty/hashtab.c:591
#1 0x000055555cb4eb2e in follow_die_offset (sect_off=(unknown: 27), offset_in_dwz=0, ref_cu=0x7fffffffc110) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:22951
#2 0x000055555cb4edfb in follow_die_ref (src_die=0x0, attr=0x7fffffffc130, ref_cu=0x7fffffffc110) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:22968
#3 0x000055555caa48c5 in partial_die_full_name (pdi=0x621000157e70, cu=0x615000023f80) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:8441
#4 0x000055555caa4d79 in add_partial_symbol (pdi=0x621000157e70, cu=0x615000023f80) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:8469
#5 0x000055555caa7d8c in add_partial_subprogram (pdi=0x621000157e70, lowpc=0x7fffffffc5c0, highpc=0x7fffffffc5e0, set_addrmap=1, cu=0x615000023f80) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:8737
#6 0x000055555caa265c in scan_partial_symbols (first_die=0x621000157e00, lowpc=0x7fffffffc5c0, highpc=0x7fffffffc5e0, set_addrmap=1, cu=0x615000023f80) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:8230
#7 0x000055555ca98e3f in process_psymtab_comp_unit_reader (reader=0x7fffffffc6b0, info_ptr=0x60600009650d "\003int", comp_unit_die=0x621000157d10, pretend_language=language_minimal) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:7614
#8 0x000055555ca9aa2c in process_psymtab_comp_unit (this_cu=0x621000155510, per_objfile=0x613000009f80, want_partial_unit=false, pretend_language=language_minimal) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:7712
#9 0x000055555caa051a in dwarf2_build_psymtabs_hard (per_objfile=0x613000009f80) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:8073
The special thing about this DWARF is that the subprogram at 0x1b is a
template specialization described with DW_AT_specification, and has no
DW_AT_name in itself. To compute the name of this subprogram,
partial_die_full_name needs to load the full DIE for this partial DIE.
The name is generated from the templated function name and the actual
tempalate parameter values of the specialization.
To load the full DIE, partial_die_full_name creates a dummy DWARF
attribute of form DW_FORM_ref_addr that points to our subprogram's DIE,
and calls follow_die_ref on it. This eventually causes
load_full_comp_unit to be called for the exact same CU we are currently
making partial symbols for:
#0 load_full_comp_unit (this_cu=0x621000155510, per_objfile=0x613000009f80, skip_partial=false, pretend_language=language_minimal) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:9238
#1 0x000055555cb4e943 in follow_die_offset (sect_off=(unknown: 27), offset_in_dwz=0, ref_cu=0x7fffffffc110) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:22942
#2 0x000055555cb4edfb in follow_die_ref (src_die=0x0, attr=0x7fffffffc130, ref_cu=0x7fffffffc110) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:22968
#3 0x000055555caa48c5 in partial_die_full_name (pdi=0x621000157e70, cu=0x615000023f80) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:8441
#4 0x000055555caa4d79 in add_partial_symbol (pdi=0x621000157e70, cu=0x615000023f80) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:8469
#5 0x000055555caa7d8c in add_partial_subprogram (pdi=0x621000157e70, lowpc=0x7fffffffc5c0, highpc=0x7fffffffc5e0, set_addrmap=1, cu=0x615000023f80) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:8737
#6 0x000055555caa265c in scan_partial_symbols (first_die=0x621000157e00, lowpc=0x7fffffffc5c0, highpc=0x7fffffffc5e0, set_addrmap=1, cu=0x615000023f80) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:8230
#7 0x000055555ca98e3f in process_psymtab_comp_unit_reader (reader=0x7fffffffc6b0, info_ptr=0x60600009650d "\003int", comp_unit_die=0x621000157d10, pretend_language=language_minimal) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:7614
#8 0x000055555ca9aa2c in process_psymtab_comp_unit (this_cu=0x621000155510, per_objfile=0x613000009f80, want_partial_unit=false, pretend_language=language_minimal) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:7712
#9 0x000055555caa051a in dwarf2_build_psymtabs_hard (per_objfile=0x613000009f80) at /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:8073
load_full_comp_unit creates a cutu_reader for the CU. Since a dwarf2_cu
object already exists for the CU, load_full_comp_unit is expected to
find it and pass it to cutu_reader, so that cutu_reader doesn't create
a new dwarf2_cu for the CU.
And this is the difference between before and after the regression.
Before commit 7188ed02d2, the dwarf2_per_cu_data -> dwarf2_cu link was
a simple pointer in dwarf2_per_cu_data. This pointer was set up when
starting the read the partial symbols. So it was already available at
that point where load_full_comp_unit gets called. Post-7188ed02d2a7,
this link is per-objfile, kept in the dwarf2_per_objfile::m_dwarf2_cus
hash map. The entry is only put in the hash map once the partial
symbols have been successfully read, when cutu_reader::keep is called.
Therefore, it is _not_ set at the point load_full_comp_unit is called.
As a consequence, a new dwarf2_cu object gets created and initialized by
load_full_comp_unit (including initializing that dwarf2_cu::die_hash
field). Meanwhile, the dwarf2_cu object created and used by the callers
up the stack does not get initialized for full symbol reading, and the
dwarf2_cu::die_hash field stays unexpectedly NULL.
Solution
--------
Since the caller of load_full_comp_unit knows about the existing
dwarf2_cu object for the CU we are reading (the one load_full_comp_unit
is expected to find), we can simply make it pass it down, instead of
having load_full_comp_unit look up the per-objfile map.
load_full_comp_unit therefore gets a new `existing_cu` parameter. All
other callers get updated to pass `per_objfile->get_cu (per_cu)`, so the
behavior shouldn't change for them, compared to the current HEAD.
A test is added, which is the bare minimum to reproduce the issue.
Notes
-----
The original problem was reproduced by downloading
https://github.com/oneapi-src/oneTBB/releases/download/v2020.3/tbb-2020.3-lin.tgz
and loading libtbb.so in GDB. This code was compiled with the Intel
C/C++ compiler. I was not able to reproduce the issue using GCC, I
think because GCC puts a DW_AT_name in the specialized subprogram, so
there's no need for partial_die_full_name to load the full DIE of the
subprogram, and the faulty code doesn't execute.
gdb/ChangeLog:
PR gdb/26693
* dwarf2/read.c (load_full_comp_unit): Add existing_cu
parameter.
(load_cu): Pass existing CU.
(process_imported_unit_die): Likewise.
(follow_die_offset): Likewise.
gdb/testsuite/ChangeLog:
PR gdb/26693
* gdb.dwarf2/template-specification-full-name.exp: New test.
Change-Id: I57c8042f96c45f15797a3848e4d384181c56bb44
Currently pointers to all partial symbols are stored in two vectors;
and then indices into these vectors are stored in each partial_symtab.
This patch changes this so that each partial symtab instead has
vectors of symbols. add_psymbol_to_list can now be changed into a
method on partial_symtab as well.
My main motivation for doing this is that I am looking into calling
sort_pst_symbols in the background. However, I haven't actually
implemented this yet. (Also this may make it more feasible to also
sort the static psymbols, though I haven't tried that either.)
Also, though, this lets us remove the "current_global_psymbols"
vector, because now the callers can simply refer directly to the
psymtab that they are modifying (formerly this was implicit).
The main drawback of this patch is that it increases the size of
partial symtab.
gdb/ChangeLog
2020-10-17 Tom Tromey <tom@tromey.com>
* xcoffread.c (xcoff_end_psymtab): Use partial_symtab::empty.
(scan_xcoff_symtab): Update.
* psymtab.h (class psymtab_storage) <global_psymbols,
static_psymbols, current_global_psymbols,
current_static_psymbols>: Remove.
* psymtab.c (require_partial_symbols, find_pc_sect_psymbol)
(match_partial_symbol, lookup_partial_symbol): Update.
(print_partial_symbols): Change parameters.
(dump_psymtab, recursively_search_psymtabs)
(psym_fill_psymbol_map, psym_find_compunit_symtab_by_address)
(sort_pst_symbols, partial_symtab::partial_symtab): Update.
(concat): Remove.
(end_psymtab_common): Simplify.
(append_psymbol_to_list): Change parameters.
(partial_symtabs::add_psymbol): Rename from add_psymbol_to_list.
(init_psymbol_list): Simplify.
(maintenance_info_psymtabs, maintenance_check_psymtabs): Update.
* psympriv.h (struct partial_symtab) <empty>: New method.
<globals_offset, n_global_syms, statics_offset, n_static_syms>:
Remove.
<global_psymbols, static_psymbols>: New members.
<add_psymbol>: New methods.
(add_psymbol_to_list): Don't declare.
(psymbol_placement): Move earlier.
* mdebugread.c (parse_partial_symbols): Update.
(handle_psymbol_enumerators): Change parameters.
(mdebug_expand_psymtab): Update.
* dwarf2/read.c (process_psymtab_comp_unit_reader)
(add_partial_symbol): Update.
* dwarf2/index-write.c (write_psymbols): Change parameters.
(write_one_signatured_type): Update.
(recursively_count_psymbols): Update.
(recursively_write_psymbols): Update.
(class debug_names) <recursively_write_psymbols>: Update.
<write_psymbols>: Change parameters.
<write_one_signatured_type>: Update.
* dbxread.c (read_dbx_symtab): Update.
(dbx_end_psymtab): Use partial_symtab::empty.
* ctfread.c (struct ctf_context) <pst>: New member.
(create_partial_symtab): Set it.
(ctf_psymtab_type_cb, ctf_psymtab_var_cb): Update.
(scan_partial_symbols): Use the psymtab's context. Update.
The type-safe attribute patch introduced a regression that can occur
when the DW_AT_bit_offset value is negative. This can happen with
some Ada programs.
This patch fixes the problem. It also fixes a minor oddity in the
existing scalar storage test -- this test was intended to assign a
smaller number of bits to the field.
2020-10-09 Tom Tromey <tromey@adacore.com>
* dwarf2/read.c (dwarf2_add_field): Handle signed offsets.
gdb/testsuite/ChangeLog
2020-10-09 Tom Tromey <tromey@adacore.com>
* gdb.ada/scalar_storage/storage.adb (Another_Range): New type.
(Rec): Add field. Fix range.
* gdb.ada/scalar_storage.exp: Update.
GDB complaints "During symbol reading: unrecognized DW_MACFINO
opcode 0xb" with the testcase given below. Clang is emitting
DW_MACRO_define_strx and DW_MACRO_undef_strx entries in .debug_macro
section which are not supported in GDB. This patch handles them.
DW_MACRO_define_strx and DW_MACRO_undef_strx are added in DWARFv5.
They have two operands. The first operand encodes the line number of
the #define or #undef macro directive. The second operand identifies
a string; it is represented using an unsigned LEB128 encoded value,
which is interpreted as a zero-based index into an array of offsets
in the .debug_str_offsets section. This is as per the section 6.3.2.1
of Dwarf Debugging Information Format Version 5.
Test case used:
#define MAX_SIZE 10
int main(void)
{
int size = 0;
size = size + MAX_SIZE;
printf("\n The value of size is [%d]\n",size);
return 0;
}
clang -gdwarf-5 -fdebug-macro macro.c -o macro.out
Before the patch:
gdb/new_gdb/binutils-gdb/build/bin/gdb -q macro.out -ex "set complaints 1" -ex "start"
Reading symbols from macro.out...
During symbol reading: unrecognized DW_MACFINO opcode 0xb
Temporary breakpoint 1 at 0x4004df: file macro.c, line 7.
Starting program: /home/nitika/workspace/macro.out
Temporary breakpoint 1, main () at macro.c:7
7 int size = 0;
(gdb)
Tested by running the testsuite before and after the patch with
-gdwarf-5 and there is no increase in the number of test cases
that fails. Used clang 11.0.0.
gdb/ChangeLog:
* dwarf2/macro.c (dwarf_decode_macro_bytes): Handle DW_MACRO_define_strx
and DW_MACRO_undef_strx.
(dwarf_decode_macros): Likewise
* dwarf2/read.c (dwarf_decode_macros): Pass str_offsets_base in the parameters
which is the value of DW_AT_str_offsets_base.
* dwarf2/macro.h (dwarf_decode_macros): Modify the definition to include
str_offsets_base.
Since commit 2c830f5475 "Change some uses of DW_STRING to string method" we
have these regressions:
...
FAIL: gdb.base/info-types-c++.exp: info types
FAIL: gdb.cp/anon-struct.exp: print type of t::t
FAIL: gdb.cp/anon-struct.exp: print type of X::t2
FAIL: gdb.cp/anon-struct.exp: print type of X::t2::t2
FAIL: gdb.cp/anon-struct.exp: print type of t3::~t3
...
Fix these in dwarf2_name by updating attr_name each time attr is updated.
Tested on x86_64-linux.
gdb/ChangeLog:
2020-09-30 Tom de Vries <tdevries@suse.de>
PR symtab/26683
* dwarf2/read.c (dwarf2_name): Update attr_name after attr is updated.
My series to change DWARF attribute handling to be type-safe
introduced a regression in gdb.ada/variant.exp. handle_variant was
using as_unsigned on an attribute with DW_FORM_sdata. This patch
changes it to use constant_value instead.
2020-09-30 Tom Tromey <tromey@adacore.com>
* dwarf2/read.c (handle_variant): Use constant_value.
This removes DW_UNSND, replacing uses with either as_unsigned or
constant_value, depending primarily on whether or not the form is
already known to be appropriate.
gdb/ChangeLog
2020-09-29 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (lookup_dwo_id, get_type_unit_group)
(read_file_scope, dwarf2_get_pc_bounds)
(dwarf2_record_block_ranges, dwarf2_add_field, get_alignment)
(read_structure_type, handle_struct_member_die)
(read_enumeration_type, read_array_type, read_set_type)
(read_tag_pointer_type, read_tag_reference_type)
(read_subroutine_type, read_base_type, read_subrange_type)
(read_full_die_1, partial_die_info::read)
(partial_die_info::read, by, new_symbol)
(dwarf2_const_value_data, dwarf2_const_value_attr)
(dump_die_shallow, dwarf2_fetch_constant_bytes)
(prepare_one_comp_unit): Update.
* dwarf2/attribute.h (DW_UNSND): Remove.
This adds a new attribute::as_boolean method, and updates the reader
to use it. The main benefit of this change is that now the code will
respect the attribute's form.
gdb/ChangeLog
2020-09-29 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (read_func_scope, prototyped_function_p)
(read_subroutine_type, partial_die_info::read)
(dwarf2_flag_true_p, new_symbol, dump_die_shallow)
(dwarf2_add_member_fn): Update.
* dwarf2/attribute.h (struct attribute) <as_boolean>: Declare.
* dwarf2/attribute.c (attribute::as_boolean): New method.
This adds a new attribute::as_virtuality method and changes the DWARF
reader to use it. This also ensures that the attibute's form will now
be respected.
gdb/ChangeLog
2020-09-29 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (dwarf2_add_field, dwarf2_add_member_fn): Update.
* dwarf2/attribute.h (struct attribute) <as_virtuality>: New
method.
* dwarf2/attribute.c (attribute::as_virtuality): New method.
This changes is_valid_DW_AT_defaulted to be a method on struct attribute.
Now it correctly respects the form of the attribute.
gdb/ChangeLog
2020-09-29 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (is_valid_DW_AT_defaulted): Move to attribute.c.
(dwarf2_add_member_fn): Update.
* dwarf2/attribute.h (struct attribute) <defaulted>: Declare.
* dwarf2/attribute.c (attribute::defaulted): New method, from
is_valid_DW_AT_defaulted.
