Finally, we can remove dw2_add_symbol_to_list since the wrapper function
originally introduced to catch this multi-language scenario is no longer
needed. With multi-language dictionaries, we can now support adding
symbols of multiple languages, negating the need for the assertion
entirely.
This patch should now fix gdb/23712 (and symtab/23010). At least it will
if the NULL buildsym_compunit problem doesn't strike first (see gdb/23773).
gdb/ChangeLog:
PR gdb/23712
PR symtab/23010
* dwarf2read.c (dw2_add_symbol_to_list): Remove.
(fixup_go_packaging, new_symbol): Use add_symbol_to_list.
This adds a new method to psymtab_storage to allocate storage for
psymtab dependencies, then changes the symbol readers to use it. This
has the effect of moving the storage to the psymtab storage obstack.
gdb/ChangeLog
2019-01-10 Tom Tromey <tom@tromey.com>
* xcoffread.c (xcoff_end_psymtab): Use allocate_dependencies.
* psymtab.h (psymtab_storage::allocate_dependencies): New method.
* mdebugread.c (parse_partial_symbols): Use
allocate_dependencies.
* dwarf2read.c (dwarf2_create_include_psymtab): Use
allocate_dependencies.
(process_psymtab_comp_unit_reader)
(build_type_psymtab_dependencies): Likewise.
* dbxread.c (dbx_end_psymtab): Use allocate_dependencies.
After this patch, the psymtab address map will now be allocated on the
psymtab obstack rather than the objfile obstack. This also changes
the psymtab storage object to make the obstack private; this will be
used later.
gdb/ChangeLog
2019-01-10 Tom Tromey <tom@tromey.com>
* psymtab.h (psymtab_storage::obstack): New method.
<m_obstack>: Rename from obstack; now private.
* psymtab.c (psymtab_storage): Update.
* dwarf2read.c (create_addrmap_from_index)
(create_addrmap_from_aranges, dwarf2_build_psymtabs_hard):
Update.
This introduces a new psymtab_storage class, which holds all
psymbol-related objects that are independent of the objfile. (This
latter contraint explains why psymbol_map was not moved; though this
could still be done with some work.)
This patch does not yet change where psymtab allocation is done --
that comes later. This just wraps everything in a single object to
make further transformations simpler.
Note that a shared_ptr is used to link from the objfile to the
psymtab_storage object. The end goal here is to allow a given symbol
reader to simply attach to the psymtab_storage object to the BFD, then
reuse it in later invocations; shared_ptr makes this simple to reason
about.
gdb/ChangeLog
2019-01-10 Tom Tromey <tom@tromey.com>
* symmisc.c (print_symbol_bcache_statistics): Update.
(print_objfile_statistics): Update.
* symfile.c (reread_symbols): Update.
* psymtab.h (class psymtab_storage): New.
* psymtab.c (psymtab_storage): New constructor.
(~psymtab_storage): New destructor.
(require_partial_symbols): Update.
(ALL_OBJFILE_PSYMTABS_REQUIRED): Rewrite.
(find_pc_sect_psymtab, find_pc_sect_psymbol)
(match_partial_symbol, lookup_partial_symbol, dump_psymtab)
(psym_dump, recursively_search_psymtabs, psym_has_symbols)
(psym_find_compunit_symtab_by_address, sort_pst_symbols)
(start_psymtab_common, end_psymtab_common)
(add_psymbol_to_bcache, add_psymbol_to_list, init_psymbol_list)
(allocate_psymtab): Update.
(psymtab_storage::discard_psymtab): Rename from discard_psymtab.
Update.
(dump_psymtab_addrmap, maintenance_print_psymbols)
(maintenance_check_psymtabs): Update.
(class objfile_psymtabs): Move to objfiles.h.
* psympriv.h (discard_psymtab): Now inline.
(psymtab_discarder::psymtab_discarder): Update.
(psymtab_discarder::~psymtab_discarder): Update.
(ALL_OBJFILE_PSYMTABS): Rewrite.
* objfiles.h (struct objfile) <psymtabs, psymtabs_addrmap,
free_psymtabs, psymbol_cache, global_psymbols, static_psymbols>:
Remove fields.
<partial_symtabs>: New field.
(class objfile_psymtabs): Move from psymtab.h. Update.
* objfiles.c (objfile::objfile): Initialize partial_symtabs, not
psymbol_cache.
(objfile::~objfile): Don't destroy psymbol_cache.
* mdebugread.c (parse_partial_symbols): Update.
* dwarf2read.c (create_addrmap_from_index)
(create_addrmap_from_aranges, dw2_find_pc_sect_compunit_symtab)
(process_psymtab_comp_unit_reader, dwarf2_build_psymtabs_hard)
(add_partial_subprogram, dwarf2_ranges_read): Update.
* dwarf-index-write.c (write_address_map)
(write_one_signatured_type, recursively_write_psymbols)
(class debug_names, class debug_names, write_psymtabs_to_index):
Update.
Existing callers to init_psymbol_list were checking to see if psymbols
had already been initialized. It seemed better to me to do this check
directly in init_psymbol_list, simplifying the callers.
gdb/ChangeLog
2019-01-10 Tom Tromey <tom@tromey.com>
* xcoffread.c (xcoff_initial_scan): Unconditionally call
init_psymbol_list.
* psymtab.c (init_psymbol_list): Do nothing if already called.
* psympriv.h (init_psymbol_list): Add comment.
* dwarf2read.c (dwarf2_build_psymtabs): Unconditionally call
init_psymbol_list.
* dbxread.c (dbx_symfile_read): Unconditionally call
init_psymbol_list.
This changes add_psymbol_to_list to use an enum, rather than a pointer
to a vector, to decide where to put the new symbol. This reduces the
number of direct references to the static_psymbols and global_psymbols
members of the objfile, which is handy in a later patch.
gdb/ChangeLog
2019-01-10 Tom Tromey <tom@tromey.com>
* xcoffread.c (scan_xcoff_symtab): Update.
* psymtab.c (add_psymbol_to_list): Replace "list" parameter with
"where".
* mdebugread.c (parse_partial_symbols)
(handle_psymbol_enumerators): Update.
* dwarf2read.c (add_partial_symbol, load_partial_dies): Update.
* dbxread.c (read_dbx_symtab): Update.
* psympriv.h (psymbol_placement): New enum.
(add_psymbol_to_list): Update.
start_psymtab_common takes references to the global_psymbols and
static_psymbols vectors, but it also has an objfile parameter. This
is redundant, so this patch simplifies the function by removing those
reference parameters.
gdb/ChangeLog
2019-01-10 Tom Tromey <tom@tromey.com>
* xcoffread.c (xcoff_start_psymtab): Remove global_psymbols and
static_psymbols parameters.
(scan_xcoff_symtab): Update.
* psymtab.c (start_psymtab_common): Remove global_psymbols and
static_psymbols parameters.
* psympriv.h (start_psymtab_common): Update.
* mdebugread.c (parse_partial_symbols): Update.
* dwarf2read.c (create_partial_symtab): Update.
* dbxread.c (read_dbx_symtab): Update.
(start_psymtab): Remove global_psymbols and static_psymbols
parameters.
allocate_psymtab has long cleared the new psymtab that is returned.
This patch documents this behavior and then removes some redundant
initializations.
gdb/ChangeLog
2019-01-10 Tom Tromey <tom@tromey.com>
* xcoffread.c (xcoff_end_psymtab): Remove some initializations.
* psymtab.c (allocate_psymtab): Add comment.
* psympriv.h (allocate_psymtab): Add comment.
* dwarf2read.c (dwarf2_create_include_psymtab): Remove some
initializations.
* dbxread.c (dbx_end_psymtab): Remove some initializations.
This commit applies all changes made after running the gdb/copyright.py
script.
Note that one file was flagged by the script, due to an invalid
copyright header
(gdb/unittests/basic_string_view/element_access/char/empty.cc).
As the file was copied from GCC's libstdc++-v3 testsuite, this commit
leaves this file untouched for the time being; a patch to fix the header
was sent to gcc-patches first.
gdb/ChangeLog:
Update copyright year range in all GDB files.
In an earlier patch discussion we noticed that
dwarf2_find_containing_comp_unit takes the address of sect_off, but
doesn't actually need to. This is a leftover from before
C++-ification. This patch simplifies the function.
Tested using gdb.dwarf2 on x86-64 Fedora 28.
gdb/ChangeLog
2018-12-18 Tom Tromey <tom@tromey.com>
* dwarf2read.c (dwarf2_find_containing_comp_unit): Don't take
address of sect_off.
In the dwarf reader we have a set of predicates, these include the
different producer predicates and also some control predicates. The
older ones are declared as integers, while newer ones (added since the
C++ conversion) are bool.
This commit makes them all bool for consistency. There should be no
user visible change after this commit.
gdb/ChangeLog:
* dwarf2read.c (struct dwarf2_cu): Convert the fields 'mark',
'has_loclist', 'checked_producer', 'producer_is_gxx_lt_4_6',
'producer_is_gcc_lt_4_3', 'producer_is_icc_lt_14',
'processing_has_namespace_info' from unsigned int to bool. Update
comments.
(producer_is_icc_lt_14): Update return type.
(producer_is_gcc_lt_4_3): Likewise.
(producer_is_gxx_lt_4_6): Likewise.
(process_die): Write true instead of 1 into predicate fields.
(dwarf2_start_symtab): Likewise.
(var_decode_location): Likewise.
(dwarf2_mark_helper): Likewise.
(dwarf2_mark): Likewise.
(dwarf2_clear_marks): Write false instead of 0 into predicate
field.
(dwarf2_cu::dwarf2_cu): Initialise predicate fields to false, not
0.
Building for x86_64/-m32 with --enable-64-bit-bfd, compilation fails
with:
src/gdb/dwarf2read.c: In instantiation of ‘gdb::array_view<const unsigned char> get_gdb_index_contents_from_section(objfile*, T*) [with T = dwarf2_per_objfile]’:
src/gdb/dwarf2read.c:6266:54: required from here
src/gdb/dwarf2read.c:6192:37: error: narrowing conversion of ‘section->dwarf2_section_info::size’ from ‘bfd_size_type {aka long long unsigned int}’ to ‘size_t {aka unsigned int}’ inside { } [-Werror=narrowing]
return {section->buffer, section->size};
~~~~~~~~~^~~~
This fixes it.
gdb/ChangeLog:
2018-12-07 Pedro Alves <palves@redhat.com>
* dwarf2read.c (get_gdb_index_contents_from_section): Use
gdb::make_array_view.
First of all, I would like to express my gratitude to Keith Seitz, Jan
Kratochvil and Tom Tromey, who were really kind and helped a lot with
this bug. The patch itself was authored by Jan.
This all began with:
https://bugzilla.redhat.com/show_bug.cgi?id=1639242
py-bt is broken, results in exception
In summary, the error reported by the bug above is:
$ gdb -args python3
GNU gdb (GDB) Fedora 8.1.1-3.fc28
(...)
Reading symbols from python3...Reading symbols from /usr/lib/debug/usr/bin/python3.6-3.6.6-1.fc28.x86_64.debug...done.
done.
Dwarf Error: could not find partial DIE containing offset 0x316 [in module /usr/lib/debug/usr/bin/python3.6-3.6.6-1.fc28.x86_64.debug]
After a long investigation, and after thinking that the problem might
actually be on DWZ's side, we were able to determine that there's
something wrong going on when
dwarf2read.c:dwarf2_find_containing_comp_unit performs a binary search
over all of the CUs belonging to an objfile in order to find the CU
which contains a DIE at an specific offset. The current algorithm is:
static struct dwarf2_per_cu_data *
dwarf2_find_containing_comp_unit (sect_offset sect_off,
unsigned int offset_in_dwz,
struct dwarf2_per_objfile *dwarf2_per_objfile)
{
struct dwarf2_per_cu_data *this_cu;
int low, high;
const sect_offset *cu_off;
low = 0;
high = dwarf2_per_objfile->all_comp_units.size () - 1;
while (high > low)
{
struct dwarf2_per_cu_data *mid_cu;
int mid = low + (high - low) / 2;
mid_cu = dwarf2_per_objfile->all_comp_units[mid];
cu_off = &mid_cu->sect_off;
if (mid_cu->is_dwz > offset_in_dwz
|| (mid_cu->is_dwz == offset_in_dwz && *cu_off >= sect_off))
high = mid;
else
low = mid + 1;
}
For the sake of this example, let's consider that "sect_off =
0x7d".
There are a few important things going on here. First,
"dwarf2_per_objfile->all_comp_units ()" will be sorted first by
whether the CU is a DWZ CU, and then by cu->sect_off. In this
specific bug, "offset_in_dwz" is false, which means that, for the most
part of the loop, we're going to do "high = mid" (i.e, we'll work with
the lower part of the vector).
In our particular case, when we reach the part where "mid_cu->is_dwz
== offset_in_dwz" (i.e, both are false), we end up with "high = 2" and
"mid = 1". I.e., there are only 2 elements in the vector who are not
DWZ. The vector looks like this:
#0: cu->sect_off = 0; length = 114; is_dwz = false <-- low
#1: cu->sect_off = 114; length = 7796; is_dwz = false <-- mid
#2: cu->sect_off = 0; length = 28; is_dwz = true <-- high
...
The CU we want is #1, which is exactly where "mid" is. Also, #1 is
not DWZ, which is also exactly what we want. So we perform the second
comparison:
(mid_cu->is_dwz == offset_in_dwz && *cu_off >= sect_off)
^^^^^^^^^^^^^^^^^^^
Because "*cu_off = 114" and "sect_off = 0x7d", this evaluates to
false, so we end up with "low = mid + 1 = 2", which actually gives us
the wrong CU (i.e., a CU that is DWZ). Next in the code, GDB does:
gdb_assert (low == high);
this_cu = dwarf2_per_objfile->all_comp_units[low];
cu_off = &this_cu->sect_off;
if (this_cu->is_dwz != offset_in_dwz || *cu_off > sect_off)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
{
if (low == 0 || this_cu->is_dwz != offset_in_dwz)
error (_("Dwarf Error: could not find partial DIE containing "
"offset %s [in module %s]"),
sect_offset_str (sect_off),
bfd_get_filename (dwarf2_per_objfile->objfile->obfd));
...
Triggering the error we saw in the original bug report.
It's important to notice that we see the error message because the
selected CU is a DWZ one, but we're looking for a non-DWZ CU here.
However, even when the selected CU is *not* a DWZ (and we don't see
any error message), we still end up with the wrong CU. For example,
suppose that the vector had:
#0: cu->sect_off = 0; length = 114; is_dwz = false
#1: cu->sect_off = 114; length = 7796; is_dwz = false
#2: cu->sect_off = 7910; length = 28; is_dwz = false
...
I.e., #2's "is_dwz" is false instead of true. In this case, we still
want #1, because that's where the DIE is located. After the loop ends
up in #2, we have "is_dwz" as false, which is what we wanted, so we
compare offsets. In this case, "7910 >= 0x7d", so we set "mid = high
= 2". Next iteration, we have "mid = 0 + (2 - 0) / 2 = 1", and thus
we examining #1. "is_dwz" is still false, but "114 >= 0x7d" also
evaluates to false, so "low = mid + 1 = 2", which makes the loop stop.
Therefore, we end up choosing #2 as our CU, even though #1 is the
right one.
The problem here is happening because we're comparing "sect_off"
directly against "*cu_off", while we should actually be comparing
against "*cu_off + mid_cu->length" (i.e., the end offset):
...
|| (mid_cu->is_dwz == offset_in_dwz
&& *cu_off + mid_cu->length >= sect_off))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...
And this is what the patch does. The idea is that if GDB is searching
for an offset that falls above the *end* of the CU being
analyzed (i.e., "mid"), then the next iteration should try a
higher-offset CU next. The previous algorithm was using
the *beginning* of the CU.
Unfortunately, I could not devise a testcase for this problem, so I am
proposing a fix with this huge explanation attached to it in the hope
that it is sufficient. After talking a bit to Keith (our testcase
guru), it seems that one would have to create an objfile with both DWZ
and non-DWZ sections, which may prove very hard to do, I think.
I ran this patch on our BuildBot, and no regressions were detected.
gdb/ChangeLog:
2018-11-30 Jan Kratochvil <jan.kratochvil@redhat.com>
Keith Seitz <keiths@redhat.com>
Tom Tromey <tom@tromey.com>
Sergio Durigan Junior <sergiodj@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=1613614
* dwarf2read.c (dwarf2_find_containing_comp_unit): Add
'mid_cu->length' to '*cu_off' when checking if 'sect_off' is
inside the CU.
In this commit:
commit eb77c9df9f
Date: Thu Oct 18 14:04:27 2018 +0100
gdb: Handle ICC's unexpected void return type
A potential dereference of a NULL pointer was introduced if a
DW_TAG_base_type is missing a DW_AT_name attribute.
I have taken this opportunity to fix a slight confusion that existed
in the test also added in the above commit, the test had two C
variables, declared like this:
int var_a = 5;
void *var_ptr = &var_a;
However, the fake DWARF in the test script declared them like this:
void var_a = 5;
void *var_ptr = &var_a;
This wasn't a problem as the test never uses 'var_a' directly, this
only exists so 'var_ptr' can be initialised. However, it seemed worth
fixing.
I've also added a test for a DW_TAG_base_type with a missing
DW_AT_name, as clearly there's not test currently that covers this
(the original patch tested cleanly). I can confirm that the new test
causes GDB to crash before this patch, and passes with this patch.
gdb/ChangeLog:
* dwarf2read.c (dwarf2_init_integer_type): Check for name being
NULL before dereferencing it.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/void-type.exp: Rename types, and make var_a an 'int'.
* gdb.dwarf2/missing-type-name.exp: New file.
I encountered a binary compiled with Intel's C Compiler (ICC) version
14.0.5.212, which seemed to contain some non-standard DWARF.
The DWARF spec (V5 3.3.2) says:
Debugging information entries for C void functions should not have
an attribute for the return type.
However, what I observed in the DWARF from this ICC compiled binary
was this:
...
<0><857>: Abbrev Number: 1 (DW_TAG_compile_unit)
<858> DW_AT_comp_dir : (indirect string, offset: 0x48d): /tmp/
<85c> DW_AT_language : 1 (ANSI C)
<85d> DW_AT_name : (indirect string, offset: 0x77c): filename.c
<861> DW_AT_producer : (indirect string, offset: 0x520): Intel(R) C Intel(R) 64 Compiler ...
<865> DW_AT_low_pc : 0x4378d0
<86d> DW_AT_high_pc : 0x4378f0
<875> DW_AT_stmt_list : 0xa37
...
<1><7ea>: Abbrev Number: 2 (DW_TAG_base_type)
<7eb> DW_AT_byte_size : 0
<7ec> DW_AT_encoding : 5 (signed)
<7ed> DW_AT_name : (indirect string, offset: 0x58f): void
...
<1><7f1>: Abbrev Number: 3 (DW_TAG_subprogram)
<7f2> DW_AT_decl_line : 268
<7f4> DW_AT_decl_column : 30
<7f5> DW_AT_decl_file : 1
<7f6> DW_AT_type : <0x7ea>
<7fa> DW_AT_prototyped : 1
<7fb> DW_AT_name : (indirect string, offset: 0x761): function_foo
<7ff> DW_AT_MIPS_linkage_name: (indirect string, offset: 0x761): function_foo
<803> DW_AT_low_pc : 0x4378a0
<80b> DW_AT_high_pc : 0x4378d0
<813> DW_AT_external : 1
...
So function 'function_foo' has void return type, but still has a
DW_AT_type attribute for a 0 sized type called void.
What was found was that when the 'finish' command was used to leave
'function_foo', GDB would crash.
The problem is that in infcmd.c:print_return_value GDB tries to filter
out void return types, by looking for the TYPE_CODE_VOID, this fails
for the 'void' type as it has code TYPE_CODE_INT and GDB then tries to
print the 'void' type.
This eventually ends in a call to valprint.c:maybe_negate_by_bytes,
however, the len (length) of the value being negated is 0, which is
not detected or expected by this code, and invalid memory accesses
occur, some of which might cause GDB to crash.
The above DWARF was seen on version 14.0.5.212 of ICC.
I have also tested ICC versions 18.0.2.199 and 17.0.7.259, on both of
these versions, the DW_AT_type on the DW_TAG_subprogram has been
removed, bringing ICC inline with the DWARF standard, and with the
DWARF produced by GCC.
I only have limited access to these specific versions of ICC so I am
unable to get more specific details for when the generated DWARF
became non-standard or when it was changed to be more inline with the
DWARF standard.
Further testing revealed additional places where ICC produced 'void'
related DWARF that GDB struggles with. When I compiled code that
contained a function with this signature:
void funcx (void *arg);
on ICC 17/18, I got the following DWARF (notice the void return type
is now gone):
...
<1><32>: Abbrev Number: 2 (DW_TAG_subprogram)
<33> DW_AT_decl_line : 2
<34> DW_AT_decl_file : 1
<35> DW_AT_prototyped : 1
<36> DW_AT_name : (indirect string, offset: 0xc5): funcx
<3a> DW_AT_MIPS_linkage_name: (indirect string, offset: 0xc5): funcx
<3e> DW_AT_low_pc : 0x6dc
<46> DW_AT_high_pc : 0x703
<4e> DW_AT_external : 1
<2><4f>: Abbrev Number: 3 (DW_TAG_formal_parameter)
<50> DW_AT_decl_line : 2
<51> DW_AT_decl_file : 1
<52> DW_AT_type : <0x6a>
<56> DW_AT_name : arg
<5a> DW_AT_location : 2 byte block: 76 70 (DW_OP_breg6 (rbp): -16)
...
<1><6a>: Abbrev Number: 5 (DW_TAG_pointer_type)
<6b> DW_AT_type : <0x6f>
<1><6f>: Abbrev Number: 6 (DW_TAG_base_type)
<70> DW_AT_byte_size : 0
<71> DW_AT_encoding : 5 (signed)
<72> DW_AT_name : (indirect string, offset: 0xcb): void
...
However, the function argument 'arg' does still reference a 'void'
type. This case doesn't seem as obviously non-standard as the
previous one, but I think that the DWARF standard (V5 5.2) does
suggest that the above is not the recommended approach. If we compare
to the DWARF generated by GCC 7.3.1:
...
<1><68>: Abbrev Number: 5 (DW_TAG_subprogram)
<69> DW_AT_external : 1
<69> DW_AT_name : (indirect string, offset: 0x221): funcx
<6d> DW_AT_decl_file : 1
<6e> DW_AT_decl_line : 2
<6f> DW_AT_prototyped : 1
<6f> DW_AT_low_pc : 0x400487
<77> DW_AT_high_pc : 0x22
<7f> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<81> DW_AT_GNU_all_call_sites: 1
<81> DW_AT_sibling : <0xa0>
<2><85>: Abbrev Number: 6 (DW_TAG_formal_parameter)
<86> DW_AT_name : arg
<8a> DW_AT_decl_file : 1
<8b> DW_AT_decl_line : 2
<8c> DW_AT_type : <0xa0>
<90> DW_AT_location : 2 byte block: 91 58 (DW_OP_fbreg: -40)
...
<1><a0>: Abbrev Number: 7 (DW_TAG_pointer_type)
<a1> DW_AT_byte_size : 8
...
Here we see that the DW_TAG_pointer_type doesn't reference any further
type. This also seems out of line with the DWARF standard (which I
think recommends using a DW_TAG_unspecified_type entry), however GDB
does handle the GCC generated DWARF better.
If we look at how GDB handles the DWARF from GCC, then we see this:
(gdb) print *arg
Attempt to dereference a generic pointer.
While on the current HEAD of master dereferencing arg causes undefined
behaviour which will likely crash GDB (for the same reason as was
described above for the 'finish' case). On earlier versions of GDB
the ICC DWARF would cause this:
(gdb) print *arg
$1 = 0
In this patch both the return type, and general variable/parameter
type handling is fixed by transforming the synthetic void entries in
the DWARF, the ones that look like this:
<1><6f>: Abbrev Number: 6 (DW_TAG_base_type)
<70> DW_AT_byte_size : 0
<71> DW_AT_encoding : 5 (signed)
<72> DW_AT_name : (indirect string, offset: 0xcb): void
into GDB's builtin void type. My criteria for performing the fix are:
1. Binary produced by any version of ICC,
2. We're producing an integer type,
3. The size is 0, and
4. The name is "void".
I ignore the signed / unsigned nature of the integer.
Potentially we could drop the ICC detection too, this should be a
reasonably safe transformation to perform, however, I'm generally
pretty nervous when it comes to modifying how the DWARF is parsed so,
for now, I have restricted this to ICC only.
I also added an assertion to maybe_negate_by_bytes. This is nothing
to do with the actual fix, but should detect incorrect use of this
function in the future, without relying on undefined behaviour to
crash GDB.
I added a new test that makes use the of the testsuite's DWARF
generator. As it is tricky to create target independent tests that
pass function parameters using the DWARF generator (as specifying the
argument location is target specific) I have instead made use of a
global variable void*. This still shows the issue.
We already have a predicate in the DWARF parser to detect versions of
ICC prior to 14, however, this issue was spotted on a later version.
As a result I've added a new predicate that is true for any version of
ICC.
gdb/ChangeLog:
* dwarf2read.c (struct dwarf2_cu): Add producer_is_icc field.
(producer_is_icc): New function.
(check_producer): Set producer_is_icc field on dwarf2_cu.
(dwarf2_init_integer_type): New function.
(read_base_type): Call dwarf2_init_integer_type instead of
init_integer_type in all cases.
(dwarf2_cu::dwarf2_cu): Initialise producer_is_icc field.
* valprint.c (maybe_negate_by_bytes): Add an assertion that the
LEN is greater than 0.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/void-type.c: New file.
* gdb.dwarf2/void-type.exp: New file.
This removes a couple of DEF_VECs from symtab.h, replacing them with
std::vector at the points of use.
gdb/ChangeLog
2018-10-26 Tom Tromey <tom@tromey.com>
* dwarf2read.c (recursively_compute_inclusions): Use std::vector.
(compute_compunit_symtab_includes): Update.
* symtab.h: (symtab_ptr): Remove typedef. Don't define a VEC.
(compunit_symtab_ptr): Likewise.
This commit fixes a buffer overrun found by Coverity, where
36 bytes are written into a 24 byte buffer.
gdb/ChangeLog:
* dwarf2read.c (create_dwp_hash_table): Fix buffer overrun
found by Coverity.
gdb/ChangeLog:
* dwarf2read.c (dwarf2_cu) <producer_is_codewarrior>: New field.
(check_producer): Check if the producer is codewarrior.
(producer_is_codewarrior): New function.
(lnp_state_machine::record_line): Ignore is_stmt flag for records
produced by codewarrior.
(dwarf2_cu::dwarf2_cu): Initialize producer_is_codewarrior.
This fixes all the straightforward -Wshadow=local warnings in gdb. A
few standard approaches are used here:
* Renaming an inner (or outer, but more commonly inner) variable;
* Lowering a declaration to avoid a clash;
* Moving a declaration into a more inner scope to avoid a clash,
including the special case of moving a declaration into a loop header.
I did not consider any of the changes in this patch to be particularly
noteworthy, though of course they should all still be examined.
gdb/ChangeLog
2018-10-04 Tom Tromey <tom@tromey.com>
* ctf.c (SET_ARRAY_FIELD): Rename "u32".
* p-valprint.c (pascal_val_print): Split inner "i" variable.
* xtensa-tdep.c (xtensa_push_dummy_call): Declare "i" in loop
header.
* xstormy16-tdep.c (xstormy16_push_dummy_call): Declare "val" in
more inner scope.
* xcoffread.c (read_xcoff_symtab): Rename inner "symbol".
* varobj.c (varobj_update): Rename inner "newobj",
"type_changed".
* valprint.c (generic_emit_char): Rename inner "buf".
* valops.c (find_overload_match): Rename inner "temp".
(value_struct_elt_for_reference): Declare "v" in more inner
scope.
* v850-tdep.c (v850_push_dummy_call): Rename "len".
* unittests/array-view-selftests.c (run_tests): Rename inner
"vec".
* tui/tui-stack.c (tui_show_frame_info): Declare "i" in loop
header.
* tracepoint.c (merge_uploaded_trace_state_variables): Declare
"tsv" in more inner scope.
(print_one_static_tracepoint_marker): Rename inner
"tuple_emitter".
* tic6x-tdep.c (tic6x_analyze_prologue): Declare "inst" lower.
(tic6x_push_dummy_call): Don't redeclare "addr".
* target-float.c: Declare "dto" lower.
* symtab.c (lookup_local_symbol): Rename inner "sym".
(find_pc_sect_line): Rename inner "pc".
* stack.c (print_frame): Don't redeclare "gdbarch".
(return_command): Rename inner "gdbarch".
* s390-tdep.c (s390_prologue_frame_unwind_cache): Renam inner
"sp".
* rust-lang.c (rust_internal_print_type): Declare "i" in loop
header.
* rs6000-tdep.c (ppc_process_record): Rename inner "addr".
* riscv-tdep.c (riscv_push_dummy_call): Declare "info" in inner
scope.
* remote.c (remote_target::update_thread_list): Don't redeclare
"tp".
(remote_target::process_initial_stop_replies): Rename inner
"thread".
(remote_target::remote_parse_stop_reply): Don't redeclare "p".
(remote_target::wait_as): Don't redeclare "stop_reply".
(remote_target::get_thread_local_address): Rename inner
"result".
(remote_target::get_tib_address): Likewise.
I get the following error with gcc 6.3.0:
/home/simark/src/binutils-gdb/gdb/dwarf2read.c: In function 'void read_func_scope(die_info*, dwarf2_cu*)':
/home/simark/src/binutils-gdb/gdb/dwarf2read.c:13838:12: error: types may not be defined in a for-range-declaration [-Werror]
for (struct symbol *sym : template_args)
^~~~~~
Removing the struct keyword fixes it.
gdb/ChangeLog:
* dwarf2read.c (read_func_scope): Remove struct keyword in
range-based for.
-fsanitize=undefined pointed out that read_signed_leb128 had an
undefined left-shift when processing the final byte of a 64-bit leb:
runtime error: left shift of 127 by 63 places cannot be represented in type 'long int'
and an undefined negation:
runtime error: negation of -9223372036854775808 cannot be represented in type 'long int'; cast to an unsigned type to negate this value to itself
Both of these problems are readily avoided by havinng
read_signed_leb128 work in an unsigned type, and then casting to the
signed type at the return.
gdb/ChangeLog
2018-10-03 Tom Tromey <tom@tromey.com>
* dwarf2read.c (read_signed_leb128): Work in ULONGEST.
-fsanitize=undefined pointed out an undefined shift of a negative
value in read_subrange_type. The fix is to do the work in an unsigned
type, where this is defined.
gdb/ChangeLog
2018-10-03 Tom Tromey <tom@tromey.com>
* dwarf2read.c (read_subrange_type): Make "negative_mask"
unsigned.
Consider a vla variable 'a' in function f1:
...
<2><1a7>: Abbrev Number: 11 (DW_TAG_variable)
<1a8> DW_AT_description : a
<1aa> DW_AT_abstract_origin: <0x311>
...
with abstract origin 'a':
...
<2><311>: Abbrev Number: 3 (DW_TAG_variable)
<312> DW_AT_name : a
<317> DW_AT_type : <0x325>
...
and inherited abstract vla type:
...
<1><325>: Abbrev Number: 9 (DW_TAG_array_type)
<326> DW_AT_type : <0x33a>
<2><32e>: Abbrev Number: 10 (DW_TAG_subrange_type)
<32f> DW_AT_type : <0x2ea>
<333> DW_AT_upper_bound : 5 byte block: fd 1b 3 0 0
(DW_OP_GNU_variable_value: <0x31b>)
...
where the upper bound refers to this artificial variable D.1922 without location
attribute:
...
<2><31b>: Abbrev Number: 8 (DW_TAG_variable)
<31c> DW_AT_description : (indirect string, offset: 0x39a): D.1922
<320> DW_AT_type : <0x2ea>
<324> DW_AT_artificial : 1
...
Currently, when we execute "p sizeof (a)" in f1, the upper bound is calculated
by evaluating the DW_OP_GNU_variable_value expression referring to D.1922, but
since that die doesn't have a location attribute, we get:
...
value has been optimized out
...
However, there's also artificial variable D.4283 that is sibling of vla
variable 'a', has artificial variable D.1922 as abstract origin, and has a
location attribute:
...
<2><1ae>: Abbrev Number: 12 (DW_TAG_variable)
<1af> DW_AT_description : (indirect string, offset: 0x1f8): D.4283
<1b3> DW_AT_abstract_origin: <0x31b>
<1b7> DW_AT_location : 11 byte block: 75 1 8 20 24 8 20 26 31 1c 9f
(DW_OP_breg5 (rdi):1; DW_OP_const1u: 32;
DW_OP_shl; DW_OP_const1u: 32; DW_OP_shra;
DW_OP_lit1; DW_OP_minus; DW_OP_stack_value)
...
The intended behaviour for DW_OP_GNU_variable_value is to find a die that
refers to D.1922 as abstract origin, has a location attribute and is
'in scope', so the expected behaviour is:
...
$1 = 6
...
The 'in scope' concept can be thought of as variable D.1922 having name
attribute "D.1922", and variable D.4283 inheriting that attribute, resulting
in D.4283 being declared with name "D.1922" alongside vla a in f1, and when we
lookup "DW_OP_GNU_variable_value D.1922", it should work as if we try to find
the value of a variable named "D.1922" on the gdb command line using
"p D.1922", and we should return the value of D.4283.
This patch fixes the case described above, by:
- adding a field abstract_to_concrete to struct dwarf2_per_objfile,
- using that field to keep track of which concrete dies are instances of an
abstract die, and
- using that information when getting the value DW_OP_GNU_variable_value.
Build and reg-tested on x86_64-linux.
2018-09-05 Tom de Vries <tdevries@suse.de>
* dwarf2loc.c (sect_variable_value): Call indirect_synthetic_pointer
with resolve_abstract_p == true.
(indirect_synthetic_pointer): Add resolve_abstract_p parameter,
defaulting to false. Propagate resolve_abstract_p to
dwarf2_fetch_die_loc_sect_off.
* dwarf2loc.h (dwarf2_fetch_die_loc_sect_off): Add resolve_abstract_p
parameter, defaulting to false.
* dwarf2read.c (read_variable): Add variable to abstract_to_concrete.
(dwarf2_fetch_die_loc_sect_off): Add and handle resolve_abstract_p
parameter.
* dwarf2read.h (struct die_info): Forward-declare.
(die_info_ptr): New typedef.
(struct dwarf2_per_objfile): Add abstract_to_concrete field.
* gdb.dwarf2/varval.exp: Add test.
gdb represents a DW_TAG_variant_part as a union. While normally DWARF
would not set the size of a DW_TAG_variant_part, gdb's representation
requires the TYPE_LENGTH to be set.
This patch arranges to set the TYPE_LENGTH of a variant part if it has
not already been set.
This fixes some Rust regressions when testing against a version of
rustc that emits DW_TAG_variant_part.
gdb/ChangeLog
2018-08-31 Tom Tromey <tom@tromey.com>
* dwarf2read.c (dwarf2_add_field): Set the TYPE_LENGTH of the
variant part type.
This change sets BLOCK_RANGES for the block under consideration by
calling make_blockranges(). This action is performed in
dwarf2_record_block_ranges().
It should be noted that dwarf2_record_block_ranges() already does some
recording of the range via a call to record_block_range(). The ranges
recorded in that fashion end up in the address map associated with the
blockvector for the compilation unit's symtab. Given an address, the
addrmap provides a fast way of finding the block containing that
address. The address map does not, however, provide a convenient way
of determining which address ranges make up a particular block.
While reading a set of ranges, a vector of pairs is used to collect
the starting and ending addresses for each range in the block. Once
all of the ranges for a block have been collected, make_blockranges()
is called to fill in BLOCK_RANGES for the block.
The ranges are stored for the block in the order that they're read
from the debug info. For DWARF, the starting address of the first
range of the block will be the entry pc in cases where DW_AT_entry_pc
is not present. (Well, that would ideally be the case. At the moment
DW_AT_entry_pc is not being handled.)
gdb/ChangeLog:
* dwarf2read.c (dwarf2_record_block_ranges): Fill in BLOCK_RANGES
for block.
New in v3:
- Remove things related to the dwarf-5 format.
- Fix compilation on mingw (scoped_mmap.c).
GDB can generate indexes for DWARF debug information, which, when
integrated in the original binary, can speed up loading object files.
This can be done using the gdb-add-index script or directly by the
linker itself. However, not many people know about this. And even
among those who do, because it requires additional steps, I don't know a
lot of people who actually go through that trouble.
To help make using the DWARF index more transparent, this patch
introduces a DWARF index cache. When enabled, loading an index-less
binary in GDB will automatically save an index file in ~/.cache/gdb.
When loading that same object file again, the index file will be looked
up and used to load the DWARF index. You therefore get the benefit of
the DWARF index without having to do additional manual steps or
modifying your build system. When an index section is already present
in the file, GDB will prefer that one over looking up the cache.
When doing my edit-compile-debug cycle, I often debug multiple times the
same build, so the cache helps reducing the load time of the debug
sessions after the first one.
- The saved index file is exactly the same as the output of the "save
gdb-index" command. It is therefore the exact same content that would
be found in the .gdb_index or .debug_names section. We just leave it
as a standalone file instead of merging it in the binary.
- The cache is just a directory with files named after the object
file's build-id. It is not possible to save/load the index for an
object file without build-id in the cache.
- The cache uses the gdb index format. The problem with the dwarf-5
format is that we can generate an addendum to the .debug_str section
that you're supposed to integrate to the original binary. This
complicates a little bit loading the data from the cached index files,
so I would leave this for later.
- The size taken up by ~/.cache/gdb is not limited. I was thinking we
could add configurable limit (like ccache does), but that would come
after. Also, maybe a command to flush the cache.
- The cache is disabled by default. I think once it's been out there
and tested for a while, it could be turned on by default, so that
everybody can enjoy it.
- The code was made to follow the XDG specification: if the
XDG_CACHE_HOME environment variable, it is used, otherwise it falls
back to ~/.cache/gdb. It is possible to change it using "set
index-cache directory". On other OSes than GNU/Linux, ~/.cache may
not be the best place to put such data. On macOS it should probably
default to ~/Library/Caches/... On Windows, %LocalAppData%/... I
don't intend to do this part, but further patches are welcome.
- I think that we need to be careful that multiple instances of GDB
don't interfere with each other (not far fetched at all if you run GDB
in some automated script) and the cache is always coherent (either the
file is not found, or it is found and entirely valid). Writing the
file directly to its final location seems like a recipe for failure.
One GDB could read a file in the index while it is being written by
another GDB. To mitigate this, I made write_psymtabs_to_index write
to temporary files and rename them once it's done. Two GDB instances
writing the index for the same file should not step on each other's
toes (the last file to be renamed will stay). A GDB looking up a file
will only see a complete file or no file. Also, if GDB crashes while
generating the index file, it will leave a work-in-progress file, but
it won't be picked up by other instances looking up in the cache.
gdb/ChangeLog:
* common/pathstuff.h (get_standard_cache_dir): New.
* common/pathstuff.c (get_standard_cache_dir): New.
* build-id.h (build_id_to_string): New.
* dwarf-index-common.h (INDEX4_SUFFIX, INDEX5_SUFFIX,
DEBUG_STR_SUFFIX): Move to here.
* dwarf-index-write.c (INDEX4_SUFFIX, INDEX5_SUFFIX,
DEBUG_STR_SUFFIX): Move from there.
(write_psymtabs_to_index): Make non-static, add basename
parameter. Write to temporary files, rename when done.
(save_gdb_index_command): Adjust call to
write_psymtabs_to_index.
* dwarf2read.h (dwarf2_per_objfile) <index_cache_res>: New
field.
* dwarf2read.c (dwz_file) <index_cache_res>: New field.
(get_gdb_index_contents_from_cache): New.
(get_gdb_index_contents_from_cache_dwz): New.
(dwarf2_initialize_objfile): Read index from cache.
(dwarf2_build_psymtabs): Save to index.
* dwarf-index-cache.h: New file.
* dwarf-index-cache.c: New file.
* dwarf-index-write.h: New file.
gdb/testsuite/ChangeLog:
* boards/index-cache-gdb.exp: New file.
* gdb.dwarf2/index-cache.exp: New file.
* gdb.dwarf2/index-cache.c: New file.
* gdb.base/maint.exp: Check if we are using the index cache.
New in v3:
- Remove changed to dwarf-5 functions.
The read_gdb_index_from_section and read_debug_names_from_section
functions read the index content, as their names state, from sections of
object files. A following patch will make it possible to read index
content from standalone files.
This patch therefore decouples the code that reads the index content
from the code that processes that content. Functions
dwarf2_read_gdb_index and dwarf2_read_debug_names receive callbacks that
are responsible for providing the index contents (for both the main file
and the potential dwz file).
gdb/ChangeLog:
* dwarf2read.c (read_gdb_index_from_section): Rename to...
(read_gdb_index_from_buffer): ... this. Remove section
parameter, add buffer parameter.
(get_gdb_index_contents_ftype,
get_gdb_index_contents_dwz_ftype): New typedefs.
(dwarf2_read_gdb_index): Add callback parameters to get the
index contents.
(get_gdb_index_contents_from_section): New.
(dwarf2_initialize_objfile): Update call to
dwarf2_read_gdb_index.
PR symtab/16842 shows that gdb will crash when the user tries to
invoke "info address" of a template parameter.
The bug here is that dwarf2read.c does not set the symtab on the
template parameter symbols. This is pedantically correct, given that
the template symbols do not appear in a symtab. However, gdb
primarily uses the symtab backlink to find the symbol's objfile. So,
this patch simply sets the symtab on these symbols.
Tested by the buildbot.
gdb/ChangeLog
2018-08-02 Tom Tromey <tom@tromey.com>
PR symtab/16842.
* dwarf2read.c (read_func_scope): Set symtab on template parameter
symbols.
(process_structure_scope): Likewise.
gdb/testsuite/ChangeLog
2018-08-02 Tom Tromey <tom@tromey.com>
PR symtab/16842.
* gdb.cp/temargs.exp: Test "info address" of a template
parameter.
This patch finally makes partial symbols and partial symtabs
independent of the program space.
Specifically:
It changes add_psymbol_to_list to accept a section index, and changes
the psymbol readers to pass this. At the same time it removes the
code to add the objfile's section offset to the psymbol.
It adds an objfile argument to the psymtab textlow and texthigh
accessors and changes some code to use the raw variants instead.
It removes the "relocate" method from struct quick_symbol_functions,
as it is no longer needed any more.
It changes partial_symbol::address so that the relevant offset is now
applied at the point of use.
gdb/ChangeLog
2018-07-26 Tom Tromey <tom@tromey.com>
* dwarf-index-write.c (add_address_entry): Don't add objfile
offsets.
* dbxread.c (find_stab_function): Rename from
find_stab_function_addr. Return a bound_minimal_symbol.
(read_dbx_symtab): Use raw_text_low, raw_text_high.
Don't add objfile offsets.
(end_psymtab): Use raw_text_low, raw_text_high,
MSYMBOL_VALUE_RAW_ADDRESS.
(read_ofile_symtab): Update.
(process_one_symbol): Update.
* dwarf2read.c (create_addrmap_from_index): Don't add objfile
offsets.
(dw2_relocate): Remove.
(dw2_find_pc_sect_symtab): Bias PC by the text offset before
searching addrmap.
(dwarf2_gdb_index_functions, dwarf2_debug_names_functions):
Update.
(process_psymtab_comp_unit_reader, add_partial_symbol)
(add_partial_subprogram, dwarf2_ranges_read): Update.
(load_partial_dies): Update.
(add_address_entry): Don't add objfile offsets.
(dwarf2_build_include_psymtabs): Update.
(create_addrmap_from_aranges): Don't add objfile offsets.
(dw2_find_pc_sect_compunit_symtab): Update.
* mdebugread.c (parse_symbol): Don't add objfile offsets.
(parse_lines): Remove 'pst' parameter, replace with 'textlow'.
Update.
(parse_partial_symbols): Don't add objfile offsets. Use
raw_text_low, raw_text_high. Update.
(handle_psymbol_enumerators, psymtab_to_symtab_1): Update.
* objfiles.c (objfile_relocate1): Don't relocate psymtabs_addrmap
or call 'relocate' quick function. Clear psymbol_map.
* psympriv.h (struct partial_symbol) <address>: Add section
offset.
<set_unrelocated_address>: Rename from set_address.
<raw_text_low, raw_text_high>: New methods.
<text_low, text_high>: Add objfile parameter.
(add_psymbol_to_bcache): Add 'section' parameter. Call
set_unrelocated_address.
* psymtab.c (find_pc_sect_psymtab_closer, find_pc_sect_psymtab)
(find_pc_psymbol): Update.
(fixup_psymbol_section, relocate_psymtabs): Remove.
(dump_psymtab, psym_functions): Update.
(add_psymbol_to_bcache, add_psymbol_to_list): Add 'section'
parameter.
(maintenance_info_psymtabs, maintenance_check_psymtabs): Update.
(start_psymtab_common): Update.
* symfile-debug.c (debug_qf_relocate): Remove.
(debug_sym_quick_functions): Update.
* symfile.h (struct quick_symbol_functions) <relocate>: Remove.
* xcoffread.c (scan_xcoff_symtab): Don't add objfile offsets.
Update.
This introduces accessors for the partial symbol table textlow and
texthigh fields. This lets us later arrange to relocate these values
at their point of use.
I did this conversion by renaming the fields. I didn't rename the
fields back afterward, thinking that on the off chance that someone
has a patch touching this area, then a merge would helpfully break
their compile.
I looked at making the fields private, but this interferes with the
memset in allocate_psymtab, and I didn't want to chase this down.
This conversion can be done later if need be.
gdb/ChangeLog
2018-07-26 Tom Tromey <tom@tromey.com>
* dbxread.c (read_dbx_symtab, end_psymtab, read_ofile_symtab):
Update.
* dwarf2read.c (dwarf2_create_include_psymtab): Don't initialize
textlow and texthigh fields.
(process_psymtab_comp_unit_reader, dwarf2_build_include_psymtabs):
Update.
* mdebugread.c (parse_lines, parse_partial_symbols)
(psymtab_to_symtab_1): Update.
* psympriv.h (struct partial_symtab) <m_text_low, m_text_high>:
Rename fields. Update comment. Now private.
<text_low, text_high, set_text_low, set_text_high>: New methods.
* psymtab.c (find_pc_sect_psymtab_closer, find_pc_sect_psymtab)
(find_pc_sect_psymbol, relocate_psymtabs, dump_psymtab)
(start_psymtab_common, maintenance_info_psymtabs)
(maintenance_check_psymtabs): Update.
* xcoffread.c (xcoff_end_psymtab): Don't initialize textlow and
texthigh fields.
(scan_xcoff_symtab): Update.
Add a maintenance command to disable the DWARF stack unwinders.
Normal users would not need this feature, but it is useful to allow
extended testing of fallback stack unwinding strategies, for example,
prologue scanners.
This is a partial implementation of the idea discussed in pr gdb/8434,
which talks about a generic ability to disable any frame unwinder.
Being able to arbitrarily disable any frame unwinder would be a more
complex patch, and I was unsure how useful such a feature would really
be, however, I can see (and have) a real need to disable DWARF
unwinders. That's why this patch only targets that specific set of
unwinders.
If in the future we find ourselves adding more switches to disable
different unwinders, then we should probably move to a more generic
solution, and remove this patch.
gdb/ChangeLog:
* dwarf2-frame-tailcall.c (tailcall_frame_sniffer): Exit early if
DWARF unwinders are disabled.
* dwarf2-frame.c: Add dwarf2read.h include.
(dwarf2_frame_sniffer): Exit early if DWARF unwinders are
disabled.
(dwarf2_frame_unwinders_enabled_p): Define.
(show_dwarf_unwinders_enabled_p): New function.
(_initialize_dwarf2_frame): Register switch to control DWARF
unwinder use.
* dwarf2-frame.h (dwarf2_frame_unwinders_enabled_p): Declare.
* dwarf2read.c (set_dwarf_cmdlist): Remove static keyword.
(show_dwarf_cmdlist): Remove static keyword.
* dwarf2read.h (set_dwarf_cmdlist): Declare.
(show_dwarf_cmdlist): Declare.
* NEWS: Document new feature.
gdb/doc/ChangeLog:
* gdb.texinfo (Maintenance Commands): Add description of
maintenance command to control dwarf unwinders.
gdb/testsuite/ChangeLog:
* gdb.base/maint.exp: Add check that dwarf unwinders control flag
is visible.
This patch generates a warning if DW_AT_upper_bound or DW_AT_count is defined,
but can't be translated. This is triggered for current gcc in lto mode for
vla test-cases.
Build and reg-tested on x86_64-linux.
2018-07-26 Tom de Vries <tdevries@suse.de>
* dwarf2read.c (read_subrange_type): Warn if DW_AT_upper_bound or
DW_AT_count can't be translated to a dynamic prop.
This patch is another attempt at really fixing the multitude of assertions
being seen where symbols of one language are being added to symbol lists of
another language.
In this specific case, the backtrace command (thread apply all bt full) that
is looking for the compunit containing the PC of the thread. That calls
get_prev_frame several times. This function calls (eventually)
dwarf2_frame_prev_register. That eventually ends up calling
find_pc_compunit_symtab.
In this function (find_pc_sect_compunit_symtab actually), we loop over all
compunits, calling the "quick" function dw2_find_pc_sect_compunit_symtab.
That function calls dw2_instantiate_symtab to read in all the CU's symbols.
Now the fun begins.
dw2_do_instantiate_symtab queues the per_cu for reading, using a default
"pretend" language of language_minimal with the expectation that this will
be set later.
The DIEs of this (only queued) CU are then processed.
The first DIE is DW_TAG_compile_unit. That's handled by read_file_scope.
(Nearly) The first thing read_file_scope does is:
get_scope_pc_bounds (die, &lowpc, &highpc, cu);
This function loops over the children of the current DIE (a compile_unit),
looking for bounds. The first such child is a subprogram, and we attempt to
get its bounds. We use dwarf2_attr to get at DW_AT_high_pc.
This subprogram has DW_AT_specification set, so dwarf_attr (via
follow_die_ref/follow_die_offset) will follow that, but follow_die_offset
*also* attempts to load the containing CU for the spec DIE. That spec DIE
lives inside a CU that is a partial_unit and has no language attribute. So
it simply inherits the language from the CU that elicited the read. [That
all happens in follow_die_offset.]
The original CU's language is still language_minimal -- we haven't gotten to
the line in read_file_scope that actually sets the language yet!
And that is the cause of these problems. The call to prepare_one_comp_unit
needs to be the *first* thing that is done when reading a CU so that the
CU's language can be recorded (and inherited by any referenced
partial_units).
Since a test reproducer for this has been so elusive, this patch also adds a
wrapper function around add_symbol_to_list which asserts when adding a
symbol of one language to a list containing symbols of a different language.
gdb/ChangeLog:
2017-07-24 Keith Seitz <keiths@redhat.com>
PR symtab/23010
* dwarf2read.c (dw2_add_symbol_to_list): New function.
(fixup_go_packaging, new_symbol): Use dw2_add_symbol_to_list
instead of add_symbol_to_list.
(read_file_scope): Call prepare_one_comp_unit before reading
any other DIEs.
This converts the DWARF reader to use the new-style buildsym API. A
new buildsym_compunit is created for each CU and is used to construct
the symbol table. In some cases the CU must be passed to functions
which previously did not accept it. FWIW I tend to think that most
methods in the DWARF reader ought to be methods on the dwarf2_cu
object.
gdb/ChangeLog
2018-07-20 Tom Tromey <tom@tromey.com>
* dwarf2read.c: Include buildsym.h.
(struct dwarf2_cu) <builder>: New method.
(fixup_go_packaging): Update.
(process_full_comp_unit, process_full_type_unit): Update. Don't
use scoped_free_pendings.
(using_directives): Add "cu" parameter, remove "language".
(read_import_statement, setup_type_unit_groups, )
(read_func_scope, read_lexical_block_scope)
(dwarf2_record_block_ranges, read_namespace): Update.
(lnp_state_machine::lnp_state_machine): Add cu parameter.
(lnp_state_machine::handle_end_sequence): Update.
(class lnp_state_machine) <m_cu>: New member.
<m_record_line_callback>: Remove.
<m_currently_recording_lines>: New member.
(lnp_state_machine::handle_set_file): Update.
(noop_record_line): Remove.
(dwarf_record_line_p): Add cu parameter.
(dwarf_record_line_1, dwarf_finish_line): Likewise.
(lnp_state_machine::record_line)
(lnp_state_machine::lnp_state_machine)
(lnp_state_machine::check_line_address, dwarf_decode_lines_1)
(dwarf_decode_lines): Update.
(dwarf2_start_subfile): Add cu parameter.
(dwarf2_start_symtab, new_symbol): Update.
(macro_start_file, dwarf_decode_macro_bytes): Add cu parameter.
Remove dwarf2_per_objfile parameter.
(dwarf_decode_macros): Update.
This changes cp_scan_for_anonymous_namespaces to use the
buildsym_compunit API, rather than the function-based API.
gdb/ChangeLog
2018-07-20 Tom Tromey <tom@tromey.com>
* stabsread.c (define_symbol): Update.
* buildsym-legacy.h (get_buildsym_compunit): Declare.
* dwarf2read.c (new_symbol): Update.
* cp-support.h (cp_scan_for_anonymous_namespaces): Update.
* cp-namespace.c: Include buildsym.h.
(cp_scan_for_anonymous_namespaces): Add "compunit" parameter.
* buildsym-legacy.c (get_buildsym_compunit): New function.
This introduces a new header, buildsym-legacy.h, and changes all the
symbol readers to use it. The idea is to put the function-based
interface, that relies on the buildsym_compunit global, into a
separate header. Then when a symbol reader is updated to use the new
interface, it can simply not include buildsym-legacy.h, so it's easy
to be sure that the new API is used everywhere.
gdb/ChangeLog
2018-07-20 Tom Tromey <tom@tromey.com>
* xcoffread.c: Include buildsym-legacy.h.
* windows-nat.c: Include buildsym-legacy.h.
* stabsread.c: Include buildsym-legacy.h.
* mdebugread.c: Include buildsym-legacy.h.
* buildsym-legacy.h: New file.
* buildsym-legacy.c: New file, from buildsym.c.
* go32-nat.c: Include buildsym-legacy.h.
* dwarf2read.c: Include buildsym-legacy.h.
* dbxread.c: Include buildsym-legacy.h.
* cp-namespace.c: Include buildsym-legacy.h.
* coffread.c: Include buildsym-legacy.h.
* buildsym.h: Move some contents to buildsym-legacy.h.
* buildsym.c: Include buildsym-legacy.h. Move many functions to
buildsym-legacy.c.
* Makefile.in (HFILES_NO_SRCDIR): Add buildsym-legacy.h.
Currently the DWARF reader sets the list_in_scope member of the CU
when first starting to process symbols. Future changes will make this
assert -- code will not be able to refer to these lists until after
start_symtab has been called. This patch prepares for the problem by
arranging to initialize list_in_scope in dwarf2_start_symtab.
gdb/ChangeLog
2018-07-20 Tom Tromey <tom@tromey.com>
* dwarf2read.c (process_full_comp_unit): Do not set list_in_scope.
(process_full_type_unit): Likewise.
(dwarf2_start_symtab): Set list_in_scope.
The DWARF reader was setting the list_in_scope member when reading
partial symbols. however, this member is only useful when reading
full symbols. Future patches will make this assert, so remove these
unneeded initializations.
gdb/ChangeLog
2018-07-20 Tom Tromey <tom@tromey.com>
* dwarf2read.c (process_psymtab_comp_unit_reader)
(build_type_psymtabs_reader): Do not set list_in_scope.
This moves the context stack globals to be members of
buildsym_compunit, changing the type to a std::vector in the process.
Because the callers expect the context stack object to be valid after
being popped, at Simon's suggestion I've changed pop_context to return
the object rather than the pointer.
gdb/ChangeLog
2018-07-20 Tom Tromey <tom@tromey.com>
* coffread.c (coff_symtab_read): Update.
* xcoffread.c (read_xcoff_symtab): Update.
* dwarf2read.c (new_symbol): Update.
(read_func_scope, read_lexical_block_scope): Update.
* dbxread.c (process_one_symbol): Update.
* buildsym.h (context_stack, context_stack_depth): Don't declare.
(outermost_context_p): Remove macro.
(outermost_context_p, get_current_context_stack)
(get_context_stack_depth): Declare.
(pop_context): Return struct context_stack.
* buildsym.c (struct buildsym_compunit) <m_context_stack: New
member.
(context_stack_size): Remove.
(INITIAL_CONTEXT_STACK_SIZE): Remove.
(prepare_for_building, end_symtab_get_static_block)
(augment_type_symtab, push_context): Update.
(pop_context): Return struct context_stack.
(outermost_context_p, get_current_context_stack)
(get_context_stack_depth): New functions.
(buildsym_init): Update.
This changes a few explicit checks of context_stack_depth to use
outermost_context_p instead. This simplifies some future work.
gdb/ChangeLog
2018-07-16 Tom Tromey <tom@tromey.com>
* xcoffread.c (read_xcoff_symtab): Use outermost_context_p.
* dwarf2read.c (using_directives, new_symbol): Use
outermost_context_p.
* dbxread.c (process_one_symbol): Use outermost_context_p.
* coffread.c (coff_symtab_read): Use outermost_context_p.
processing_gcc is also only used by stabsread -- it is set by the
DWARF reader, but this turns out not to be needed. So, this patch
moves processing_gcc and removes the assignment from the DWARF reader.
gdb/ChangeLog
2018-07-16 Tom Tromey <tom@tromey.com>
* stabsread.h (processing_gcc_compilation): Move from buildsym.h.
* dwarf2read.c (dwarf2_start_symtab): Don't set
processing_gcc_compilation.
* buildsym.h (processing_gcc_compilation): Move to stabsread.h.
The version check of the dwarf compilation unit header in
error_check_comp_unit_head is done too late, and consequently dwarf code with
an unsupported version in the compilation unit header is interpreted as dwarf5
code in read_comp_unit_head.
Fixed by moving the check earlier.
Build and reg-tested on x86_64-linux.
2018-07-04 Tom de Vries <tdevries@suse.de>
* dwarf2read.c (error_check_comp_unit_head): Move dwarf version
check ...
(read_comp_unit_head): ... here.
* gdb.dwarf2/dw2-error.exp: Update expected error message.
I noticed that dwarf2_free_objfile can be made static, by changing it
to be a registry cleanup function. This simplifies the code, as well,
because now symbol readers don't have to explicitly call it.
Tested by the buildbot.
gdb/ChangeLog
2018-06-28 Tom Tromey <tom@tromey.com>
* coffread.c (coff_symfile_finish): Update.
* xcoffread.c (xcoff_symfile_finish): Update.
* elfread.c (elf_symfile_finish): Update.
* symfile.h (dwarf2_free_objfile): Don't declare.
* dwarf2read.c (_initialize_dwarf2_read): Use
register_objfile_data_with_cleanup.
(dwarf2_free_objfile): Now static. Change signature.
This patch fixes a unique condition where GDB fails to provide line
information of symbol at address zero when code is compiled with text
address zero but loaded at an offset > 0.
For example lets compile following code snippet:
int main() {
return 0;
}
gcc -O0 -g3 -nostdlib -emain -Wl,-Ttext=0x00 -o file.out file.c
Start gdb and run:
add-symbol-file file.out 0xffff0000
info line main
GDB will return error saying no line info is available for the symbol.
This is a direct consequence of the fix for PR 12528 where GDB tries to ignore
line table for a function which has been garbage collected by the linker.
As the garbage collected symbols are sent to address zero GDB assumes a symbol
actually placed at address zero as garbage collected.
This was fixed with an additional check address < lowpc. But when symbol is
loaded at an offset lowpc becomes lowpc + offset while no offset is added to
address rather final symbol address is calculated based on baseaddr and address
added together. So in case where symbols are loaded at an offset the condition
address < lowpc will always return true.
This patch fixes this by comparing address against a non offset lowpc.
This patch also adds a GDB test case to replicate this behavior.
gdb:
2018-06-27 Omair Javaid <omair.javaid@linaro.org>
PR gdb/21695
* dwarf2read.c (lnp_state_machine::check_line_address): Update declaration.
(dwarf_decode_lines_1): Adjust.
gdb/testsuite:
2018-06-27 Omair Javaid <omair.javaid@linaro.org>
PR gdb/21695
* gdb.base/infoline-reloc-main-from-zero.exp: New test.
* gdb.base/infoline-reloc-main-from-zero.c: New file.
Keith Seitz
Tom Tromey
Joel Brobecker
Andrew Burgess
Pedro Alves
Sergio Durigan Junior
Gary Benson
John Darrington
Simon Marchi
Tom de Vries
Kevin Buettner
Simon Marchi
Omair Javaid