I recently stumbled on this code mentioning Linux kernel 2.6.25, and
thought it could be time for some spring cleaning (newer GDBs probably
don't need to supports 12-year old kernels). I then found that the
"legacy" case is probably broken anyway, which gives an even better
motivation for its removal.
In short, this patch removes the configure checks that check if
user_regs_struct contains the fs_base/gs_base fields and adjusts all
uses of the HAVE_STRUCT_USER_REGS_STRUCT_{FS,GS}_BASE macros. The
longer explanation/rationale follows.
Apparently, Linux kernels since 2.6.25 (that's from 2008) have been
reliably providing fs_base and gs_base as part of user_regs_struct.
Commit df5d438e33d7 in the Linux kernel [1] seems related. This means
that we can get these values by reading registers with PTRACE_GETREGS.
Previously, these values were obtained using a separate
PTRACE_ARCH_PRCTL ptrace call.
First, I'm not even sure the configure check was really right in the
first place.
The user_regs_struct used by GDB comes from
/usr/include/x86_64-linux-gnu/sys/user.h (or equivalent on other
distros) and is provided by glibc. glibc has had the fs_base/gs_base
fields in there for a very long time, at least since this commit from
2001 [2]. The Linux kernel also has its version of user_regs_struct,
which I think was exported to user-space at some point. It included the
fs_base/gs_base fields since at least this 2002 commit [3]. In any
case, my conclusion is that the fields were there long before the
aforementioned Linux kernel commit. The kernel commit didn't add these
fields, it only made sure that they have reliable values when obtained
with PTRACE_GETREGS.
So, checking for the presence of the fs_base/gs_base fields in struct
user_regs_struct doesn't sound like a good way of knowing if we can
reliably get the fs_base/gs_base values from PTRACE_GETREGS. My guess
is that if we were using that strategy on a < 2.6.25 kernel, things
would not work correctly:
- configure would find that the user_regs_struct has the fs_base/gs_base
fields (which are probided by glibc anyway)
- we would be reading the fs_base/gs_base values using PTRACE_GETREGS,
for which the kernel would provide unreliable values
Second, I have tried to see how things worked by forcing GDB to not use
fs_base/gs_base from PTRACE_GETREGS (forcing it to use the "legacy"
code, by configuring with
ac_cv_member_struct_user_regs_struct_gs_base=no ac_cv_member_struct_user_regs_struct_fs_base=no
Doing so breaks writing registers back to the inferior. For example,
calling an inferior functions gives an internal error:
(gdb) p malloc(10)
/home/smarchi/src/binutils-gdb/gdb/i387-tdep.c:1408: internal-error: invalid i387 regnum 152
The relevant last frames where this error happens are:
#8 0x0000563123d262fc in internal_error (file=0x563123e93fd8 "/home/smarchi/src/binutils-gdb/gdb/i387-tdep.c", line=1408, fmt=0x563123e94482 "invalid i387 regnum %d") at /home/smarchi/src/binutils-gdb/gdbsupport/errors.cc:55
#9 0x0000563123047d0d in i387_collect_xsave (regcache=0x5631269453f0, regnum=152, xsave=0x7ffd38402a20, gcore=0) at /home/smarchi/src/binutils-gdb/gdb/i387-tdep.c:1408
#10 0x0000563122c69e8a in amd64_collect_xsave (regcache=0x5631269453f0, regnum=152, xsave=0x7ffd38402a20, gcore=0) at /home/smarchi/src/binutils-gdb/gdb/amd64-tdep.c:3448
#11 0x0000563122c5e94c in amd64_linux_nat_target::store_registers (this=0x56312515fd10 <the_amd64_linux_nat_target>, regcache=0x5631269453f0, regnum=152) at /home/smarchi/src/binutils-gdb/gdb/amd64-linux-nat.c:335
#12 0x00005631234c8c80 in target_store_registers (regcache=0x5631269453f0, regno=152) at /home/smarchi/src/binutils-gdb/gdb/target.c:3485
#13 0x00005631232e8df7 in regcache::raw_write (this=0x5631269453f0, regnum=152, buf=0x56312759e468 "@\225\372\367\377\177") at /home/smarchi/src/binutils-gdb/gdb/regcache.c:765
#14 0x00005631232e8f0c in regcache::cooked_write (this=0x5631269453f0, regnum=152, buf=0x56312759e468 "@\225\372\367\377\177") at /home/smarchi/src/binutils-gdb/gdb/regcache.c:778
#15 0x00005631232e75ec in regcache::restore (this=0x5631269453f0, src=0x5631275eb130) at /home/smarchi/src/binutils-gdb/gdb/regcache.c:283
#16 0x0000563123083fc4 in infcall_suspend_state::restore (this=0x5631273ed930, gdbarch=0x56312718cf20, tp=0x5631270bca90, regcache=0x5631269453f0) at /home/smarchi/src/binutils-gdb/gdb/infrun.c:9103
#17 0x0000563123081eed in restore_infcall_suspend_state (inf_state=0x5631273ed930) at /home/smarchi/src/binutils-gdb/gdb/infrun.c:9151
The problem seems to be that amd64_linux_nat_target::store_registers
calls amd64_native_gregset_supplies_p to know whether gregset provides
fs_base. When !HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE,
amd64_native_gregset_supplies_p returns false. store_registers
therefore assumes that it must be an "xstate" register. This is of
course wrong, and that leads to the failed assertion when
i387_collect_xsave doesn't recognize the register.
amd64_linux_nat_target::store_registers could probably be fixed to
handle this case, but I don't think it's worth it, given that it would
only be to support very old kernels.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=df5d438e33d7fc914ba9b6e0d6b019a8966c5fcc
[2] https://sourceware.org/git/?p=glibc.git;a=commit;h=c9cf6ddeebb7bb
[3] https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/?id=88e4bc32686ebd0b1111a94f93eba2d334241f68
gdb/ChangeLog:
* configure.ac: Remove check for fs_base/gs_base in
user_regs_struct.
* configure: Re-generate.
* config.in: Re-generate.
* amd64-nat.c (amd64_native_gregset_reg_offset): Adjust.
* amd64-linux-nat.c (amd64_linux_nat_target::fetch_registers,
amd64_linux_nat_target::store_registers, ps_get_thread_area, ): Adjust.
gdbserver/ChangeLog:
* configure.ac: Remove check for fs_base/gs_base in
user_regs_struct.
* configure: Re-generate.
* config.in: Re-generate.
* linux-x86-low.cc (x86_64_regmap, x86_fill_gregset,
x86_store_gregset): Adjust.
This expands the Python dynamic type documentation, as suggested by
Christian.
gdb/doc/ChangeLog
2020-04-27 Tom Tromey <tromey@adacore.com>
* python.texi (Types In Python): Mention missing fields. Add
dynamic type example.
In PR 25731 [1], the following build failure was reported:
../../binutils-gdb/gdb/gdbtypes.c:1254:10: error: no member named 'abs' in namespace 'std'; did you mean simply 'abs'?
= ((std::abs (stride) * element_count) + 7) / 8;
^~~~~~~~
abs
/usr/include/stdlib.h:129:6: note: 'abs' declared here
int abs(int) __pure2;
^
The original report was using:
$ gcc -v
Apple LLVM version 8.0.0 (clang-800.0.42.1)
Target: x86_64-apple-darwin15.6.0
Note that I was _not_ able to reproduce using:
$ g++ --version
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/4.2.1
Apple clang version 11.0.0 (clang-1100.0.33.17)
Target: x86_64-apple-darwin19.3.0
The proposed fix is to include <cstdlib> in addition to <stdlib.h>.
Here's an excerpt of [2] relevant to this problem:
These headers [speaking of the .h form] are allowed to also declare
the same names in the std namespace, and the corresponding cxxx
headers are allowed to also declare the same names in the global
namespace: including <cstdlib> definitely provides std::malloc and
may also provide ::malloc. Including <stdlib.h> definitely provides
::malloc and may also provide std::malloc
Since we use std::abs, we should not assume that our include of stdlib.h
declares an `abs` function in the `std` namespace.
If we replace the include of stdlib.h with cstdlib, then we fall in the
opposite situation. A standard C++ library may decide to only put the
declarations in the std namespace, requiring us to prefix all standard
functions with `std::`. I'm not against that, but for the moment I think the
safest way forward is to just include both.
Note that I don't know what effect this patch can have on any stdlib.h fix
provided by gnulib.
[1] https://sourceware.org/bugzilla/show_bug.cgi?id=25731
[2] https://en.cppreference.com/w/cpp/header#C_compatibility_headers
gdbsupport/ChangeLog:
* common-defs.h: Include cstdlib.h.
Commit 5939967b35 fixed inline
frame unwinding breakage for some targets (aarch64, riscv, s390...)
but regressed a few amd64 testcases related to tailcalls.
Given the following example situation...
Frame #-1 - sentinel frame
Frame # 0 - inline frame
Frame # 1 - normal frame
... suppose we're at level #1 and call into dwarf2_tailcall_sniffer_first.
We'll attempt to fetch PC, which used to be done via the gdbarch_unwind_pc call
(before 5939967b35), but now it is being handled
by the get_frame_register function.
gdbarch_unwind_pc will attempt to use frame #1's cache to retrieve information
about the PC. Here's where different architectures behave differently.
x86_64 will find a dwarf rule to retrieve PC from memory, at a CFA + offset
location. So the PC value is readily available and there is no need to
create a lazy value.
For aarch64 (and others), GCC doesn't emit an explicit location for PC, so we
eventually will find that PC is DWARF2_FRAME_REG_UNSPECIFIED. This is known
and is handled by GDB by assuming GCC really meant DWARF2_FRAME_REG_SAME_VALUE.
This means we'll attempt to fetch the register value from frame #0, via a call
to frame_unwind_got_register, which will trigger the creation of a lazy value
that requires a valid frame id for frame #0.
We don't have a valid id for frame #0 yet, so we assert.
Given the above, the following patch attempts to handle the situation without
being too hacky. We verify if the next frame is an inline frame and if its
frame id has been computed already. If it hasn't been computed yet, then we
use the safer get_frame_register function, otherwise we use the regular
gdbarch_unwind_pc hook.
gdb/ChangeLog:
2020-04-27 Luis Machado <luis.machado@linaro.org>
* dwarf2/frame-tailcall.c (dwarf2_tailcall_sniffer_first): Handle
problematic inline frame unwinding situation.
* frame.c (frame_id_computed_p): New function.
* frame.h (frame_id_computed_p): New prototype.
PR 25878
* dwarf2dbg.c (struct file_entry): Add auto_assigned field.
(assign_file_to_slot): New function. Fills in an entry in the
files table.
(allocate_filenum): Use new function.
(allocate_filename_to_slot): Use new function. If the specified
slot entry is already in use, but was chosen automatically then
reassign the automatic entry.
The class_pseudo constant is unused, so this removes it.
Tested by rebuilding.
gdb/ChangeLog
2020-04-26 Tom Tromey <tom@tromey.com>
* command.h (enum command_class) <class_pseudo>: Remove.
This fixes another missing error check.
* readelf.c (get_num_dynamic_syms): Check DT_MIPS_XHASH was
read before dereferencing, and gracefully return. Remove
gnu_hash_error variable. Free gnu hash arrays if number of
syms found is zero.
Remove unused PT_GET_PROCESS_STATE block. It used to be used
by OpenBSD, but it is now reimplemented independently in
obsd-nat.c.
gdb/ChangeLog:
* inf-ptrace.c (inf_ptrace_target::wait): Remove
`PT_GET_PROCESS_STATE' block.
Change-Id: I9b872df8517b658c0dfe889fc1e4a7009bc5c076
This patch adds a target board debug-types that switches on
-fdebug-types-section by default.
This -fdebug-types-section option is a gcc option that enables the generation
of a .debug_types section, which is only effective for DWARF version 4.
There are two other boards that enable this: dwarf4-gdb-index and fisson, but
while those test some meaningful combination of options, this board is
intended to test only -fdebug-types-section.
Current results with gcc 7.5.0 are:
...
=== gdb Summary ===
# of expected passes 75832
# of unexpected failures 2841
# of expected failures 130
# of known failures 75
# of unresolved testcases 22
# of untested testcases 37
# of unsupported tests 83
...
Related known issues:
- PR gcc/90232 - "gcc drops top-level dies with -fdebug-types-section"
- PR gdb/25875 - "segv in ada_discrete_type_low_bound"
- PR gdb/14148 - "-fdebug-types-section regresses static scope of types"
Tested on x86_64-linux.
gdb/testsuite/ChangeLog:
2020-04-25 Tom de Vries <tdevries@suse.de>
* boards/debug-types.exp: New file.
Having paths in test names makes it harder to compare results from
different builds of GDB.
gdb/testsuite/ChangeLog:
* gdb.btrace/multi-inferior.exp: Avoid paths in test names.
Now that symbol_get_demangled_name is only used by general_symbol_info
methods, and because these methods already check the symbol's language
to decide what to return, symbol_get_demangled_name is no longer
needed. This patch removes it.
gdb/ChangeLog
2020-04-24 Tom Tromey <tom@tromey.com>
* symtab.h (symbol_get_demangled_name): Don't declare.
* symtab.c (symbol_get_demangled_name): Remove.
(general_symbol_info::natural_name)
(general_symbol_info::demangled_name): Update.
PR rust/25025 notes that some Rust test cases fail.
Debugging gdb revealed that the Rust compiler emits different linkage
names that demangle to the same result. Enabling complaints when
reading the test case is enough to show it:
During symbol reading: Computed physname <generics::identity<f64>> does not match demangled <generics::identity> (from linkage <_ZN8generics8identity17h8540b320af6656d6E>) - DIE at 0x424 [in module /home/tromey/gdb/build/gdb/testsuite/outputs/gdb.rust/generics/generics]
During symbol reading: Computed physname <generics::identity<u32>> does not match demangled <generics::identity> (from linkage <_ZN8generics8identity17hae302fad0c33bd7dE>) - DIE at 0x459 [in module /home/tromey/gdb/build/gdb/testsuite/outputs/gdb.rust/generics/generics]
...
This patch changes the DWARF reader to prefer the computed physname,
rather than the output of the demangler, for Rust. This fixes the
bug.
gdb/ChangeLog
2020-04-24 Tom Tromey <tom@tromey.com>
PR rust/25025:
* dwarf2/read.c (dwarf2_physname): Do not demangle for Rust.
The DWARF reader has had some odd code since the "physname" patches landed.
In particular, these patches caused PR symtab/12707; namely, they made
it so "set print demangle off" no longer works.
This patch attempts to fix the problem. It arranges to store the
linkage name on the symbol if it exists, and it changes the DWARF
reader so that the demangled name is no longer (usually) stored in the
symbol's "linkage name" field.
c-linkage-name.exp needed a tweak, because it started working
correctly. This conforms to what I think ought to happen, so this
seems like an improvement here.
compile-object-load.c needed a small change to use
symbol_matches_search_name rather than directly examining the linkage
name. Looking directly at the name does the wrong thing for C++.
There is still some name-related confusion in the DWARF reader:
* "physname" often refers to the logical name and not what I would
consider to be the "physical" name;
* dwarf2_full_name, dwarf2_name, and dwarf2_physname all exist and
return different strings -- but this seems like at least one name
too many. For example, Fortran requires dwarf2_full_name, but other
languages do not.
* To my surprise, dwarf2_physname prefers the form emitted by the
demangler over the one that it computes. This seems backward to me,
given that the partial symbol reader prefers the opposite, and it
seems to me that this choice may perform better as well.
I didn't attempt to clean up these things. It would be good to do,
but whenever I contemplate it I get caught up in dreams of truly
rewriting the DWARF reader instead.
gdb/ChangeLog
2020-04-24 Tom Tromey <tom@tromey.com>
PR symtab/12707:
* dwarf2/read.c (add_partial_symbol): Use the linkage name if it
exists.
(new_symbol): Likewise.
* compile/compile-object-load.c (get_out_value_type): Use
symbol_matches_search_name.
gdb/testsuite/ChangeLog
2020-04-24 Tom Tromey <tom@tromey.com>
PR symtab/12707:
* gdb.python/py-symbol.exp: Update expected results for
linkage_name test.
* gdb.cp/print-demangle.exp: New file.
* gdb.base/c-linkage-name.exp: Fix test.
* gdb.guile/scm-symbol.exp: Update expected results for
linkage_name test.
As mentioned in another thread, there's currently no need to call
compute_and_set_names for partial symbols. Because the DWARF partial
symbol reader constructs demangled names, this call can only demangle
a name by mistake.
So, this patch changes the DWARF reader to simply set the linkage name
on the new symbol. This is equivalent to what was done before. There
should be no user-visible change from this patch, aside from gdb
speeding up a bit.
... there *should* be, but this regressed
dw2-namespaceless-anonymous.exp. However, upon examination, I think
that test is incorrect. It puts a mangled name into DW_AT_name, and
it puts the variable at the top level, not in a namespace. This isn't
what C++ compilers ought to do. So, this patch also updates the test
case.
gdb/ChangeLog
2020-04-24 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (add_partial_symbol): Do not call
compute_and_set_names.
gdb/testsuite/ChangeLog
2020-04-24 Tom Tromey <tom@tromey.com>
* gdb.dwarf2/dw2-namespaceless-anonymous.S: Remove.
* gdb.dwarf2/dw2-namespaceless-anonymous.c: New file.
* gdb.dwarf2/dw2-namespaceless-anonymous.exp: Use DWARF
assembler.
This changes the DWARF reader to use the new add_psymbol_to_list
overload. There should be no visible changes due to this patch.
gdb/ChangeLog
2020-04-24 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (add_partial_symbol): Use new add_psymbol_to_list
overload.
This adds a new overload of add_psymbol_to_list. This one takes an
already constructed psymbol and adds it to the bcache and the
appropriate list.
This seemed cleaner than continuing to add parameters to the existing
add_psymbol_to_list, and is more in line with how full symbols are
constructed.
gdb/ChangeLog
2020-04-24 Tom Tromey <tom@tromey.com>
* psymtab.c (add_psymbol_to_bcache): Simplify calling convention.
(add_psymbol_to_list): New overload. Make old overload call new
one.
* psympriv.h (add_psymbol_to_list): New overload.
The full DIE reader checks that an attribute has a "string" form in
some spots, but the partial DIE reader does not. This patch brings
the two readers in sync for one specific case, namely when examining
the linkage name. This avoids regressions in an existing DWARF test
case.
A full fix for this problem would be preferable. An accessor like
DW_STRING should always check the form. However, I haven't attempted
that in this series.
Also the fact that the partial and full readers can disagree like this
is a design flaw.
gdb/ChangeLog
2020-04-24 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (partial_die_info::read) <case
DW_AT_linkage_name>: Use value_as_string.
(dwarf2_string_attr): Use value_as_string.
* dwarf2/attribute.h (struct attribute) <value_as_string>: Declare
method.
* dwarf2/attribute.c (attribute::value_as_string): New method.
Two methods on general_symbol_info did not handle the language_rust
case. I don't think these problems can be noticed with the current
code (which is why the bugs went unnoticed), but a future patch will
change this.
gdb/ChangeLog
2020-04-24 Tom Tromey <tom@tromey.com>
* symtab.c (general_symbol_info::natural_name)
(general_symbol_info::demangled_name): Check for language_rust.
The DWARF reader has a special case to work around a bug in some
versions of the Rust compiler -- it ignores mangled names that contain
a "{" character.
I noticed that this check should probably be in dw2_linkage_name
rather than only in dwarf2_physname. The former is called in some
cases that the latter is not.
Also, I noticed that this work is not done for the partial DIE reader,
so this patch adds the check there as well.
gdb/ChangeLog
2020-04-24 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (dw2_linkage_name): Move Rust "{" hack here...
(dwarf2_physname): ... from here.
(partial_die_info::read): Add Rust "{" hack.
This changes symbol_set_demangled_name to be a method on
general_symbol_info, and updates the users.
gdb/ChangeLog
2020-04-24 Tom Tromey <tom@tromey.com>
* symtab.h (struct general_symbol_info) <set_demangled_name>: New
method.
(symbol_set_demangled_name): Don't declare.
* symtab.c (general_symbol_info::set_demangled_name): Rename from
symbol_set_demangled_name.
(general_symbol_info::set_language)
(general_symbol_info::compute_and_set_names): Update.
* minsyms.c (minimal_symbol_reader::install): Update.
* dwarf2/read.c (new_symbol): Update.
The test-case gdb.dwarf2/dw2-bad-mips-linkage-name.exp has a CU with
language C, which contains a subprogram with a C++-mangled name as its
DW_AT_mips_linkage_name attribute.
Fix this by changing the language of the CU to C++.
Tested on x86_64-linux.
gdb/testsuite/ChangeLog:
2020-04-24 Tom de Vries <tdevries@suse.de>
* gdb.dwarf2/dw2-bad-mips-linkage-name.exp: Set language of CU to
C++.
Some test cases already work fine with minimal encodings (in some
cases perhaps due to the variant parts series) This patch updates
these tests as appropriate.
gdb/testsuite/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* gdb.ada/frame_arg_lang.exp: Run with multiple -fgnat-encodings
values.
* gdb.ada/funcall_ref.exp: Run with multiple -fgnat-encodings
values. Update test for minimal encodings.
* gdb.ada/lang_switch.exp: Update test for minimal encodings.
* gdb.ada/var_rec_arr.exp: Run with multiple -fgnat-encodings
values. Update test for minimal encodings.
This changes the gdb Python API to add support for dynamic types. In
particular, this adds an attribute to gdb.Type, and updates some
attributes to reflect dynamic sizes and field offsets.
There's still no way to get the dynamic type from one of its concrete
instances. This could perhaps be added if needed.
gdb/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
PR python/23662:
* python/py-type.c (convert_field): Handle
FIELD_LOC_KIND_DWARF_BLOCK.
(typy_get_sizeof): Handle TYPE_HAS_DYNAMIC_LENGTH.
(typy_get_dynamic): Nw function.
(type_object_getset): Add "dynamic".
* NEWS: Add entry.
gdb/doc/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
PR python/23662:
* python.texi (Types In Python): Document new features.
gdb/testsuite/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
PR python/23662:
* gdb.ada/variant.exp: Add Python checks.
* gdb.rust/simple.exp: Add dynamic type checks.
The previous patches largely came without test cases. This was done
to make the patches easier to review; as most of the patches were
needed before existing tests could be updated.
This patch adds a new test and updates some existing tests to test all
the settings of -fgnat-encodings. This ensures that tests are run
both with the old-style "magic symbol name" encoding, and the
new-style DWARF encoding.
Note that in one case, a test is modified to be more lax. See the
comment in mi_var_array.exp. I didn't want to fix this in this
series, as it's already complicated enough. However, I think it could
be fixed; I will file a bug for it.
gdb/testsuite/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* gdb.ada/mi_var_array.exp: Try all -fgnat-encodings settings.
Make array type matching more lax.
* gdb.ada/mi_var_union.exp: Try all -fgnat-encodings settings.
* gdb.ada/mi_variant.exp: New file.
* gdb.ada/mi_variant/pck.ads: New file.
* gdb.ada/mi_variant/pkg.adb: New file.
* gdb.ada/packed_tagged.exp: Try all -fgnat-encodings settings.
* gdb.ada/unchecked_union.exp: Try all -fgnat-encodings settings.
The DWARF reader was updated to handle variant parts and some other
selected features for Ada; but the Ada "ptype" code was not touched.
This patch changes the Ada ptype code to handle the new types
properly.
Test cases for this and for some of the other code in this series are
in a separate patch.
gdb/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* ada-typeprint.c (print_choices, print_variant_part)
(print_record_field_types_dynamic): New functions.
(print_record_field_types): Use print_record_field_types_dynamic.
In Ada, a field can have a variable offset. This patch adds support
for this case to gdb, using the existing dynamic type resolution code.
Doing just this, though, would break C++ virtual base handling.
It turns out that virtual base handling only worked by the ugliest of
hacks. In particular, the DWARF reader would call decode_locdesc for
a virtual base location. Here's an example of such an expression from
gdb's m-static test case:
<241> DW_AT_data_member_location: 6 byte block: 12 6 48 1c 6 22 (DW_OP_dup; DW_OP_deref; DW_OP_lit24; DW_OP_minus; DW_OP_deref; DW_OP_plus)
When examining this, decode_locdesc would treat DW_OP_deref as a no-op
and compute some answer (here, -24). This would be stored as the
offset.
Later, in gnu-v3-abi.c, the real offset would be computed by digging
around in the vtable.
This patch cleans up this area. In particular, it now evaluates the
location expression on demand.
Note there is a new FIXME in gnu-v3-abi.c. I think some of the
callers are incorrect here, and have only worked because this member
is unused. I will file a bug for this. I didn't fix this problem in
this series because I felt it was already too complex.
gdb/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* dwarf2/read.c (handle_data_member_location): New overload.
(dwarf2_add_field): Use it.
(decode_locdesc): Add "computed" parameter. Update comment.
* gdbtypes.c (is_dynamic_type_internal): Also look for
FIELD_LOC_KIND_DWARF_BLOCK.
(resolve_dynamic_struct): Handle FIELD_LOC_KIND_DWARF_BLOCK.
* gdbtypes.c (is_dynamic_type_internal): Add special case for C++
virtual base classes.
* gnu-v3-abi.c (gnuv3_baseclass_offset): Handle
FIELD_LOC_KIND_DWARF_BLOCK.
gdb/testsuite/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* gdb.ada/variant.exp: Add dynamic field offset tests.
* gdb.ada/variant/pck.ads (Nested_And_Variable): New type.
* gdb.ada/variant/pkg.adb: Add new variables.
In Ada, a type with variant parts can have a variable length. This
patch adds support for this to gdb, by integrating the length
computation into the dynamic type resolution code.
gdb/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* dwarf2/read.c (read_structure_type): Handle dynamic length.
* gdbtypes.c (is_dynamic_type_internal): Check
TYPE_HAS_DYNAMIC_LENGTH.
(resolve_dynamic_type_internal): Use TYPE_DYNAMIC_LENGTH.
* gdbtypes.h (TYPE_HAS_DYNAMIC_LENGTH, TYPE_DYNAMIC_LENGTH):
New macros.
(enum dynamic_prop_node_kind) <DYN_PROP_BYTE_SIZE>: New
constant.
gdb/testsuite/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* gdb.ada/variant.exp: New file
* gdb.ada/variant/pkg.adb: New file
* gdb.ada/variant/pck.adb: New file
This rewrites the existing variant part code to follow the new model
implemented in the previous patch. The old variant part code is
removed.
This only affects Rust for the moment. I tested this using various
version of the Rust compiler, including one that emits old-style enum
debuginfo, exercising the quirks code.
gdb/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* dwarf2/read.c (struct variant_field): Rewrite.
(struct variant_part_builder): New.
(struct nextfield): Remove "variant" field. Add "offset".
(struct field_info): Add "current_variant_part" and
"variant_parts".
(alloc_discriminant_info): Remove.
(alloc_rust_variant): New function.
(quirk_rust_enum): Update.
(dwarf2_add_field): Set "offset" member. Don't handle
DW_TAG_variant_part.
(offset_map_type): New typedef.
(convert_variant_range, create_one_variant)
(create_one_variant_part, create_variant_parts)
(add_variant_property): New functions.
(dwarf2_attach_fields_to_type): Call add_variant_property.
(read_structure_type): Don't handle DW_TAG_variant_part.
(handle_variant_part, handle_variant): New functions.
(handle_struct_member_die): Use them.
(process_structure_scope): Don't handle variant parts.
* gdbtypes.h (TYPE_FLAG_DISCRIMINATED_UNION): Remove.
(struct discriminant_info): Remove.
(enum dynamic_prop_node_kind) <DYN_PROP_DISCRIMINATED>: Remove.
(struct main_type) <flag_discriminated_union>: Remove.
* rust-lang.c (rust_enum_p, rust_empty_enum_p): Rewrite.
(rust_enum_variant): Return int. Remove "contents". Rewrite.
(rust_print_enum, rust_print_struct_def, rust_evaluate_subexp):
Update.
* valops.c (value_union_variant): Remove.
* value.h (value_union_variant): Don't declare.
When evaluating a DWARF expression, the dynamic type resolution code
will pass in a buffer of bytes via the property_addr_info. However,
the DWARF expression evaluator will then proceed to read memory from
the inferior, even when the request could be filled from this buffer.
This, in turn, is a problem in some cases; and specifically when
trying to handle the Ada scenario of extracting a variable-length
value from a packed array. Here, the ordinary DWARF expression cannot
be directly evaluated, because the data may appear at some arbitrary
bit offset. So, it is unpacked into a staging area and then the
expression is evaluated -- using an address of 0.
This patch fixes the problem by arranging for the DWARF evaluator, in
this case, to prefer passed-in memory when possible. The type of the
buffer in the property_addr_info is changed to an array_view so that
bounds checking can be done.
gdb/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* ada-lang.c (ada_discrete_type_high_bound, ada_discrete_type_low)
(ada_value_primitive_packed_val): Update.
* ada-valprint.c (ada_value_print_1): Update.
* dwarf2/loc.c (evaluate_for_locexpr_baton): New struct.
(dwarf2_locexpr_baton_eval): Take a property_addr_info rather than
just an address. Use evaluate_for_locexpr_baton.
(dwarf2_evaluate_property): Update.
* dwarf2/loc.h (struct property_addr_info) <valaddr>: Now an
array_view.
* findvar.c (default_read_var_value): Update.
* gdbtypes.c (compute_variant_fields_inner)
(resolve_dynamic_type_internal): Update.
(resolve_dynamic_type): Change type of valaddr parameter.
* gdbtypes.h (resolve_dynamic_type): Update.
* valarith.c (value_subscripted_rvalue): Update.
* value.c (value_from_contents_and_address): Update.
Some DWARF expressions must be evaluated by first pushing the object
address onto the evaluation stack. This patch adds this ability.
This functionality is not used yet, but it will be used in a later
patch. This is split out for easier review and also because it
improved the patch series ordering.
gdb/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* dwarf2/loc.c (dwarf2_locexpr_baton_eval): Add
"push_initial_value" parameter.
(dwarf2_evaluate_property): Likewise.
* dwarf2/loc.h (dwarf2_evaluate_property): Update.
This patch adds the infrastructure for the new variant part code. At
this point, nothing uses this code. This is done in a separate patch
to make it simpler to review.
I examined a few possible approaches to handling variant parts. In
particular, I considered having a DWARF variant part be a union
(similar to how the Rust code works now); and I considered having type
fields have a flag indicating that they are variants.
Having separate types seemed bad conceptually, because these variants
aren't truly separate -- they rely on the "parent" type. And,
changing how fields worked seemed excessively invasive.
So, in the end I thought the approach taken in this patch was both
simple to implement and understand, without losing generality. The
idea in this patch is that all the fields of a type with variant parts
will be stored in a single field array, just as if they'd all been
listed directly. Then, the variants are attached as a dynamic
property. These control which fields end up in the type that's
constructed during dynamic type resolution.
gdb/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* gdbtypes.c (is_dynamic_type_internal): Check for variant parts.
(variant::matches, compute_variant_fields_recurse)
(compute_variant_fields_inner, compute_variant_fields): New
functions.
(resolve_dynamic_struct): Check for DYN_PROP_VARIANT_PARTS.
Use resolved_type after type is made.
(operator==): Add new cases.
* gdbtypes.h (TYPE_HAS_VARIANT_PARTS): New macro.
(struct discriminant_range, struct variant, struct variant_part):
New.
(union dynamic_prop_data) <variant_parts, original_type>: New
members.
(enum dynamic_prop_node_kind) <DYN_PROP_VARIANT_PARTS>: New constant.
(enum dynamic_prop_kind) <PROP_TYPE, PROP_VARIANT_PARTS>: New
constants.
* value.c (unpack_bits_as_long): Now public.
* value.h (unpack_bits_as_long): Declare.
I wanted to use the name "variant" to represent a DWARF variant, but
it turned out there was an existing structure of that name. This
renames the existing variant to "ppc_variant".
gdb/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* rs6000-tdep.c (struct ppc_variant): Rename from "variant".
(variants, find_variant_by_arch, rs6000_gdbarch_init): Update.
When running test-case gdb.base/readnever.exp without commit 96038148d0
"[gdb/testsuite] Skip gdb.base/readnever.exp with target board readnow", we
run into an error:
...
ERROR: (eof) GDB never initialized.
testcase gdb/testsuite/gdb.base/readnever.exp completed in 0 seconds
...
If we additionally run test-case gdb.base/realname-expand.exp, we get an
unresolved for the first test:
...
UNRESOLVED: gdb.base/realname-expand.exp: set basenames-may-differ on
...
Using -v we find out that the UNRESOLVED is due the error triggered in the
previous test-case:
...
(gdb) set basenames-may-differ on^M
(gdb) Error/Warning threshold exceeded: 1 0 (max. 1 3)
UNRESOLVED: gdb.base/realname-expand.exp: set basenames-may-differ on
...
So, the error count of one test spills into the next test, even though we do a
clean restart. That seems like a bad idea.
Fix this by resetting errcnt (as well as warncnt) in clean_restart, such that
we have:
...
Running src/gdb/testsuite/gdb.base/readnever.exp ...
ERROR: (eof) GDB never initialized.
Running src/gdb/testsuite/gdb.base/realname-expand.exp ...
PASS: gdb.base/realname-expand.exp: set basenames-may-differ on
...
Tested on x86_64-linux.
gdb/testsuite/ChangeLog:
2020-04-24 Tom de Vries <tdevries@suse.de>
* lib/gdb.exp (clean_restart): Reset errcnt and warncnt.
The updated pending stop series introduced a regression in Windows
debugging. When stopped at a software breakpoint, we would adjust the
PC each time it was requested -- however, more than a single
adjustment is incorrect. This patch introduces a new flag that is
used to ensure the adjustment only happens a single time.
No similar change is needed in gdbserver, because it adjusts the PC in
a different way.
I still can't run the gdb test suite on Windows, but I can run the
internal AdaCore test suite there; and this fixes the regressions
there.
gdb/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* nat/windows-nat.h (struct windows_thread_info)
<pc_adjusted>: New member.
* windows-nat.c (windows_fetch_one_register): Check
pc_adjusted.
(windows_nat_target::get_windows_debug_event)
(windows_nat_target::wait): Set pc_adjusted.
When running test-case gdb.dwarf2/dwzbuildid.exp with target board
cc-with-gdb-index, we have:
...
Running src/gdb/testsuite/gdb.dwarf2/dwzbuildid.exp ...
gdb compile failed, warning: File "dwzbuildid5.o" has a different \
build-id, file skipped
could not find '.gnu_debugaltlink' file for dwzbuildid-mismatch
warning: File "dwzbuildid5.o" has a different build-id, file skipped
Error while writing index for `dwzbuildid-mismatch': could not find \
'.gnu_debugaltlink' file for dwzbuildid-mismatch
...
and likewise for target board cc-with-debug-names.
These are gdb-add-index warnings and errors due to the executable
dwzbuildid-mismatch having a build-id mismatch.
Be less verbose by adding "quiet" to the compile flags.
Tested on x86_64-linux.
gdb/testsuite/ChangeLog:
2020-04-24 Tom de Vries <tdevries@suse.de>
* gdb.dwarf2/dwzbuildid.exp: Add quiet to dwzbuildid-mismatch compile
flags.
When running test-case gdb.dwarf2/dw2-error.exp with target board
cc-with-gdb-index, we get:
...
Running src/gdb/testsuite/gdb.dwarf2/dw2-error.exp ...
gdb compile failed, Dwarf Error: wrong version in compilation unit header \
(is 153, should be 2, 3, 4 or 5) [in module \
build/gdb/testsuite/outputs/gdb.dwarf2/dw2-error/.tmp/dw2-error]
...
and similar for target board cc-with-debug-names.
Be less verbose by adding "quiet" to the compile flags.
Tested on x86_64-linux.
gdb/testsuite/ChangeLog:
2020-04-24 Tom de Vries <tdevries@suse.de>
* gdb.dwarf2/dw2-error.exp: Add quiet to compile flags.
When running test-case gdb.base/readnever.exp with target board readnow, and
without commit 96038148d0 "[gdb/testsuite] Skip gdb.base/readnever.exp with
target board readnow", we run into a bunch of errors, starting with:
...
spawn gdb -nw -nx -data-directory data-directory -ex set sysroot -readnow \
--readnever^M
gdb: '--readnow' and '--readnever' cannot be specified simultaneously^M
ERROR: : spawn id exp9 not open
while executing
"expect {
-i exp9 -timeout 10
-re "$gdb_prompt $" {
verbose "Setting height to 0." 2
}
...
The illegal combination of --readnow and --readnever causes gdb to start,
print an error message and exit. There's a gdb_expect in default_gdb_start
that is supposed to detect the initial gdb prompt and handle related problems,
but since there's no eof case it succeeds, and default_gdb_start continues as
if the gdb prompt had been detected, causing the error above.
Fix this by adding an eof case to the gdb_expect, such that we have the more
accurate:
...
ERROR: (eof) GDB never initialized.
...
Further errors are triggered in clean_restart, because we're not testing for
gdb_start success. Fix this by detecting gdb_start failure, and bailing out.
Finally, we're running into further errors in gdb.base/readnever.exp because
we're not testing for clean_restart success. Fix this by making clean_restart
return -1 upon error, and testing for this.
Tested on x86_64-linux.
gdb/testsuite/ChangeLog:
2020-04-24 Tom de Vries <tdevries@suse.de>
* lib/gdb.exp (default_gdb_start): Handle eof.
(clean_restart): Detect and handle gdb_start failure. Return -1 upon
failure.
* gdb.base/readnever.exp: Handle clean_restart failure.
When running test-case gdb.dwarf2/gdb-index.exp cleanly by issuing this
command:
...
$ rm -Rf build/gdb/testsuite/outputs/gdb.dwarf2/gdb-index
...
before running, it passes both with native and target board
cc-with-gdb-index.
But when we run the test-case first with native and then with
cc-with-gdb-index without intermediate cleanup, we get instead:
...
Running src/gdb/testsuite/gdb.dwarf2/gdb-index.exp ...
gdb compile failed, cc-with-tweaks.sh: Index file \
build/gdb/testsuite/outputs/gdb.dwarf2/gdb-index/gdb-index.gdb-index \
exists, won't clobber.
=== gdb Summary ===
# of untested testcases 1
...
What happens is that the native run produces a file
build/gdb/testsuite/outputs/gdb.dwarf2/gdb-index/gdb-index.gdb-index, which
causes gdb/contrib/cc-with-tweaks.sh to hit this code:
...
index_file="${output_file}.gdb-index"
if [ "$want_index" = true ] && [ -f "$index_file" ]
then
echo "$myname: Index file $index_file exists, won't clobber." >&2
exit 1
fi
...
The gdb-add-index script has a problem that it uses temp files alongside the
executable, filed as PR25843.
The code in cc-with-tweaks.sh attempts to detect the case that creating such a
temp file would overwrite an pre-existing file. It however does this only for
a single file, while gdb-add-index uses more temporary files:
- <exec>.gdb-index
- <exec>.debug_names
- <exec>.debug_str
- <exec>.debug_str.merge
- <exec>.debug_str.err
Fix this by working around PR25843 in a more generic way:
- move the executable into a temp directory
- execute gdb-add-index, allowing it to create any temp file alongside the
executable in the temp directory
- move the executable back to the original location
Tested on x86_64-linux, with target board cc-with-debug-index.
gdb/ChangeLog:
2020-04-24 Tom de Vries <tdevries@suse.de>
* contrib/cc-with-tweaks.sh: Remove <exec>.gdb-index file handling.
Run gdb-add-index inside temp dir.
This fixes some code that assumed only one PT_LOAD would contain
DT_SYMTAB. Which is normally the case, but fuzzers thoroughly mess
with object files.
* readelf.c (get_num_dynamic_syms): Check for nbuckets and nchains
non-zero.
(process_dynamic_section): Call get_num_dynamic_syms once rather
than in segment loop. Break out of segment loop on a successful
load of dynamic symbols. Formatting.
(process_object): Return error status from process_dynamic_section.
There were some Windows timeouts after the last merge. Debugging
showed that these were caused by an infinite loop in
is_linked_with_cygwin_dll when reading C:\Windows\SysWOW64\win32u.dll.
This patch fixes the problem by ensuring that the loop always makes
progress.
gdb/ChangeLog
2020-04-23 Tom Tromey <tromey@adacore.com>
* windows-tdep.c (is_linked_with_cygwin_dll): Always update "iter"
in loop.
There has been some breakage for aarch64-linux, arm-linux and s390-linux in
terms of inline frame unwinding. There may be other targets, but these are
the ones i'm aware of.
The following testcases started to show numerous failures and trigger internal
errors in GDB after commit 1009d92fc6,
"Find tailcall frames before inline frames".
gdb.opt/inline-break.exp
gdb.opt/inline-cmds.exp
gdb.python/py-frame-inline.exp
gdb.reverse/insn-reverse.exp
The internal errors were of this kind:
binutils-gdb/gdb/frame.c:579: internal-error: frame_id get_frame_id(frame_info*): Assertion `fi->level == 0' failed.
After a lengthy investigation to try and find the cause of these assertions,
it seems we're dealing with some fragile/poorly documented code to handle inline
frames and we are attempting to unwind from this fragile section of code.
Before commit 1009d92fc6, the tailcall sniffer
was invoked from dwarf2_frame_prev_register. By the time we invoke the
dwarf2_frame_prev_register function, we've probably already calculated the
frame id (via compute_frame_id).
After said commit, the call to dwarf2_tailcall_sniffer_first was moved to
dwarf2_frame_cache. This is very early in a frame creation process, and
we're still calculating the frame ID (so compute_frame_id is in the call
stack).
This would be fine for regular frames, but the above testcases all deal
with some inline frames.
The particularity of inline frames is that their frame ID's depend on
the previous frame's ID, and the previous frame's ID relies in the inline
frame's registers. So it is a bit of a messy situation.
We have comments in various parts of the code warning about some of these
particularities.
In the case of dwarf2_tailcall_sniffer_first, we attempt to unwind the PC,
which goes through various functions until we eventually invoke
frame_unwind_got_register. This function will eventually attempt to create
a lazy value for a particular register, and this lazy value will require
a valid frame ID. Since the inline frame doesn't have a valid frame ID
yet (remember we're still calculating the previous frame's ID so we can tell
what the inline frame ID is) we will call compute_frame_id for the inline
frame (level 0).
We'll eventually hit the assertion above, inside get_frame_id:
--
/* If we haven't computed the frame id yet, then it must be that
this is the current frame. Compute it now, and stash the
result. The IDs of other frames are computed as soon as
they're created, in order to detect cycles. See
get_prev_frame_if_no_cycle. */
gdb_assert (fi->level == 0);
--
It seems to me we shouldn't have reached this assertion without having the
inline frame ID already calculated. In fact, it seems we even start recursing
a bit when we invoke get_prev_frame_always within inline_frame_this_id. But
a check makes us quit the recursion and proceed to compute the id.
Here's the call stack for context:
#0 get_prev_frame_always_1 (this_frame=0xaaaaab85a670) at ../../../repos/binutils-gdb/gdb/frame.c:2109
RECURSION - #1 0x0000aaaaaae1d098 in get_prev_frame_always (this_frame=0xaaaaab85a670) at ../../../repos/binutils-gdb/gdb/frame.c:2124
#2 0x0000aaaaaae95768 in inline_frame_this_id (this_frame=0xaaaaab85a670, this_cache=0xaaaaab85a688, this_id=0xaaaaab85a6d0)
at ../../../repos/binutils-gdb/gdb/inline-frame.c:165
#3 0x0000aaaaaae1916c in compute_frame_id (fi=0xaaaaab85a670) at ../../../repos/binutils-gdb/gdb/frame.c:550
#4 0x0000aaaaaae19318 in get_frame_id (fi=0xaaaaab85a670) at ../../../repos/binutils-gdb/gdb/frame.c:582
#5 0x0000aaaaaae13480 in value_of_register_lazy (frame=0xaaaaab85a730, regnum=30) at ../../../repos/binutils-gdb/gdb/findvar.c:296
#6 0x0000aaaaaae16c00 in frame_unwind_got_register (frame=0xaaaaab85a730, regnum=30, new_regnum=30) at ../../../repos/binutils-gdb/gdb/frame-unwind.c:268
#7 0x0000aaaaaad52604 in dwarf2_frame_prev_register (this_frame=0xaaaaab85a730, this_cache=0xaaaaab85a748, regnum=30)
at ../../../repos/binutils-gdb/gdb/dwarf2/frame.c:1296
#8 0x0000aaaaaae1ae68 in frame_unwind_register_value (next_frame=0xaaaaab85a730, regnum=30) at ../../../repos/binutils-gdb/gdb/frame.c:1229
#9 0x0000aaaaaae1b304 in frame_unwind_register_unsigned (next_frame=0xaaaaab85a730, regnum=30) at ../../../repos/binutils-gdb/gdb/frame.c:1320
#10 0x0000aaaaaab76574 in aarch64_dwarf2_prev_register (this_frame=0xaaaaab85a730, this_cache=0xaaaaab85a748, regnum=32)
at ../../../repos/binutils-gdb/gdb/aarch64-tdep.c:1114
#11 0x0000aaaaaad52724 in dwarf2_frame_prev_register (this_frame=0xaaaaab85a730, this_cache=0xaaaaab85a748, regnum=32)
at ../../../repos/binutils-gdb/gdb/dwarf2/frame.c:1316
#12 0x0000aaaaaae1ae68 in frame_unwind_register_value (next_frame=0xaaaaab85a730, regnum=32) at ../../../repos/binutils-gdb/gdb/frame.c:1229
#13 0x0000aaaaaae1b304 in frame_unwind_register_unsigned (next_frame=0xaaaaab85a730, regnum=32) at ../../../repos/binutils-gdb/gdb/frame.c:1320
#14 0x0000aaaaaae16a84 in default_unwind_pc (gdbarch=0xaaaaab81edc0, next_frame=0xaaaaab85a730) at ../../../repos/binutils-gdb/gdb/frame-unwind.c:223
#15 0x0000aaaaaae32124 in gdbarch_unwind_pc (gdbarch=0xaaaaab81edc0, next_frame=0xaaaaab85a730) at ../../../repos/binutils-gdb/gdb/gdbarch.c:3074
#16 0x0000aaaaaad4f15c in dwarf2_tailcall_sniffer_first (this_frame=0xaaaaab85a730, tailcall_cachep=0xaaaaab85a830, entry_cfa_sp_offsetp=0x0)
at ../../../repos/binutils-gdb/gdb/dwarf2/frame-tailcall.c:388
#17 0x0000aaaaaad520c0 in dwarf2_frame_cache (this_frame=0xaaaaab85a730, this_cache=0xaaaaab85a748) at ../../../repos/binutils-gdb/gdb/dwarf2/frame.c:1190
#18 0x0000aaaaaad52204 in dwarf2_frame_this_id (this_frame=0xaaaaab85a730, this_cache=0xaaaaab85a748, this_id=0xaaaaab85a790)
at ../../../repos/binutils-gdb/gdb/dwarf2/frame.c:1218
#19 0x0000aaaaaae1916c in compute_frame_id (fi=0xaaaaab85a730) at ../../../repos/binutils-gdb/gdb/frame.c:550
#20 0x0000aaaaaae1c958 in get_prev_frame_if_no_cycle (this_frame=0xaaaaab85a670) at ../../../repos/binutils-gdb/gdb/frame.c:1927
#21 0x0000aaaaaae1cc44 in get_prev_frame_always_1 (this_frame=0xaaaaab85a670) at ../../../repos/binutils-gdb/gdb/frame.c:2006
FIRST CALL - #22 0x0000aaaaaae1d098 in get_prev_frame_always (this_frame=0xaaaaab85a670) at ../../../repos/binutils-gdb/gdb/frame.c:2124
#23 0x0000aaaaaae18f68 in skip_artificial_frames (frame=0xaaaaab85a670) at ../../../repos/binutils-gdb/gdb/frame.c:495
#24 0x0000aaaaaae193e8 in get_stack_frame_id (next_frame=0xaaaaab85a670) at ../../../repos/binutils-gdb/gdb/frame.c:596
#25 0x0000aaaaaae87a54 in process_event_stop_test (ecs=0xffffffffefc8) at ../../../repos/binutils-gdb/gdb/infrun.c:6857
#26 0x0000aaaaaae86bdc in handle_signal_stop (ecs=0xffffffffefc8) at ../../../repos/binutils-gdb/gdb/infrun.c:6381
#27 0x0000aaaaaae84fd0 in handle_inferior_event (ecs=0xffffffffefc8) at ../../../repos/binutils-gdb/gdb/infrun.c:5578
#28 0x0000aaaaaae81588 in fetch_inferior_event (client_data=0x0) at ../../../repos/binutils-gdb/gdb/infrun.c:4020
#29 0x0000aaaaaae5f7fc in inferior_event_handler (event_type=INF_REG_EVENT, client_data=0x0) at ../../../repos/binutils-gdb/gdb/inf-loop.c:43
#30 0x0000aaaaaae8d768 in infrun_async_inferior_event_handler (data=0x0) at ../../../repos/binutils-gdb/gdb/infrun.c:9377
#31 0x0000aaaaaabff970 in check_async_event_handlers () at ../../../repos/binutils-gdb/gdb/async-event.c:291
#32 0x0000aaaaab27cbec in gdb_do_one_event () at ../../../repos/binutils-gdb/gdbsupport/event-loop.cc:194
#33 0x0000aaaaaaef1894 in start_event_loop () at ../../../repos/binutils-gdb/gdb/main.c:356
#34 0x0000aaaaaaef1a04 in captured_command_loop () at ../../../repos/binutils-gdb/gdb/main.c:416
#35 0x0000aaaaaaef3338 in captured_main (data=0xfffffffff1f0) at ../../../repos/binutils-gdb/gdb/main.c:1254
#36 0x0000aaaaaaef33a0 in gdb_main (args=0xfffffffff1f0) at ../../../repos/binutils-gdb/gdb/main.c:1269
#37 0x0000aaaaaab6e0dc in main (argc=6, argv=0xfffffffff348) at ../../../repos/binutils-gdb/gdb/gdb.c:32
The following patch addresses this by using a function that unwinds the PC
from the next (inline) frame directly as opposed to creating a lazy value
that is bound to the next frame's ID (still not computed).
gdb/ChangeLog:
2020-04-23 Luis Machado <luis.machado@linaro.org>
* dwarf2/frame-tailcall.c (dwarf2_tailcall_sniffer_first): Use
get_frame_register instead of gdbarch_unwind_pc.
This is a follow-up patch on "[PATCH][gdb/symtab] Prefer def over decl
(inter-CU case)" (
https://sourceware.org/pipermail/gdb-patches/2020-April/167489.html ).
Consider the test-case from that patch. It contains a decl and def of var a
in different CUs, and tests whether var a can be printed using the def, even
if the decl is found first.
However, the test-case does this in a contextless environment, so if we add to
the test-case like this to set the context to the CU containing main:
...
gdb_test "p a" { = \{1, 2\}}
+
+if ![runto_main] then {
+ fail "can't run to main"
+ return 0
+}
+
+gdb_test "p a" { = \{1, 2\}}
...
then the second test fails, because the decl is found in the context.
Fix this by preferring defs over decls in lookup_global_symbol.
Build and reg-tested on x86_64-linux.
gdb/ChangeLog:
2020-04-23 Tom de Vries <tdevries@suse.de>
* symtab.c (lookup_global_symbol): Prefer def over decl.
gdb/testsuite/ChangeLog:
2020-04-23 Tom de Vries <tdevries@suse.de>
* gdb.base/decl-before-def.exp: Run to main and print a again.
Simon Marchi
Tom Tromey
Simon Marchi
Luis Machado
Nick Clifton
GDB Administrator
Tom Tromey
Alan Modra
Philippe Waroquiers
liuhongt
Kamil Rytarowski
Tom de Vries
Andrew Burgess
Hannes Domani