It seems like using os.getcwdu() here is wrong both for Python 2 and Python 3.
For Python 2, this returns a 'unicode' object, which tries to get concatenated
to a 'str' object in substitute_prompt. The implicit conversion works when the
unicode string contains no accent. When it does contain an accent though,
displaying the prompt results in the following error:
(gdb) set extended-prompt \w
...
File "/home/simark/build/binutils-gdb-python2/gdb/data-directory/python/gdb/prompt.py", line 138, in substitute_prompt
result += str(cmd(arg))
UnicodeEncodeError: 'ascii' codec can't encode character u'\xe9' in position 49: ordinal not in range(128)
When using os.getcwd() instead, it works correctly. I suppose that Python does
the necessary decoding internally.
For Python 3, this method simply does not exist. It works fine with os.getcwd().
gdb/ChangeLog:
* python/lib/gdb/prompt.py (_prompt_pwd): Use os.getcwd() instead of
os.getcwdu().
Currently, when we receive a request to single-step one single thread
(Eg, when single-stepping out of a breakpoint), we use the
PTRACE_SINGLESTEP pthread request, which does single-step
the corresponding thread, but also resumes execution of all
other threads in the inferior.
This causes problems when debugging programs where another thread
receives multiple debug events while trying to single-step a specific
thread out of a breakpoint (with infrun traces turned on):
(gdb) continue
Continuing.
infrun: clear_proceed_status_thread (Thread 126)
[...]
infrun: clear_proceed_status_thread (Thread 142)
[...]
infrun: clear_proceed_status_thread (Thread 146)
infrun: clear_proceed_status_thread (Thread 125)
infrun: proceed (addr=0xffffffff, signal=GDB_SIGNAL_DEFAULT, step=0)
infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=1, current thread [Thread 142] at 0x10684838
infrun: wait_for_inferior ()
infrun: target_wait (-1, status) =
infrun: 42000 [Thread 146],
infrun: status->kind = stopped, signal = GDB_SIGNAL_REALTIME_34
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x10a187f4
infrun: context switch
infrun: Switching context from Thread 142 to Thread 146
infrun: random signal (GDB_SIGNAL_REALTIME_34)
infrun: switching back to stepped thread
infrun: Switching context from Thread 146 to Thread 142
infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=1, current thread [Thread 142] at 0x10684838
infrun: prepare_to_wait
[...handling of similar events for threads 145, 144 and 143 snipped...]
infrun: prepare_to_wait
infrun: target_wait (-1, status) =
infrun: 42000 [Thread 146],
infrun: status->kind = stopped, signal = GDB_SIGNAL_REALTIME_34
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x10a187f4
infrun: context switch
infrun: Switching context from Thread 142 to Thread 146
../../src/gdb/inline-frame.c:339: internal-error: skip_inline_frames: Assertion `find_inline_frame_state (ptid) == NULL' failed.
What happens is that GDB keeps sending requests to resume one specific
thread, and keeps receiving debugging events for other threads.
Things break down when the one of the other threads receives a debug
event for the second time (thread 146 in the example above).
This patch fixes the problem by making sure that only one thread
gets resumed, thus preventing the other threads from generating
an unexpected event.
gdb/gdbserver/ChangeLog:
* lynx-low.c (lynx_resume): Use PTRACE_SINGLESTEP_ONE if N == 1.
Remove FIXME comment about assumption about N.
When running gdb on 32 bits host for 64 bits target, info mem command
truncates the target address to 32 bits, like in the example below
(gdb) set architecture powerpc:common64
(gdb) mem 0x100000000 0x200000000 rw
(gdb) info mem
1 y 0x0000000000000000 0x0000000000000000 rw nocache
gdb/ChangeLog:
PR gdb/15684
* memattr.c (mem_info_command): Remove "unsigned long" casts.
Signed-off-by: Catalin Udma <catalin.udma@freescale.com>
When there is a weak symbol with a real definition, the processor
independent code will have arranged for us to see the real definition
first. We need to copy the needs_copy bit from the real definition and
check it when allowing copy reloc in PIE.
bfd/
PR ld/17689
* elf64-x86-64.c (elf_x86_64_link_hash_entry): Add needs_copy.
Change has_bnd_reloc to bit field.
(elf_x86_64_link_hash_newfunc): Initialize needs_copy and
has_bnd_reloc to 0.
(elf_x86_64_check_relocs): Set has_bnd_reloc to 1 instead
of TRUE.
(elf_x86_64_adjust_dynamic_symbol): Copy needs_copy from the
real definition to a weak symbol.
(elf_x86_64_allocate_dynrelocs): Also check needs_copy of a
weak symbol for PIE when discarding space for relocs against
symbols which turn out to need copy relocs.
(elf_x86_64_relocate_section): Also check needs_copy of a
weak symbol for PIE with copy reloc.
ld/testsuite/
PR ld/17689
* ld-x86-64/pr17689.out: New file.
* ld-x86-64/pr17689.rd: Likewise.
* ld-x86-64/pr17689a.c: Likewise.
* ld-x86-64/pr17689b.S: Likewise.
* ld-x86-64/x86-64.exp: Run PR ld/17689 tests.
Trying to print the value of a string whose size is not known at
compile-time before it gets assigned a value can lead to the following
internal error:
(gdb) p my_str
$1 =
/[...]/utils.c:1089: internal-error: virtual memory exhausted.
What happens is that my_str is described as a reference to an array
type whose bounds are dynamic. During the read of that variable's
value (in default_read_var_value), we end up resolving dynamic types
which, for reference types, makes us also resolve the target of that
reference type. This means we resolve our variable to a reference
to an array whose bounds are undefined, and unfortunately very far
appart.
So, when we pass that value to ada-valprint, and in particular to
da_val_print_ref, we eventually try to allocate too large of a buffer
corresponding to the (bogus) size of our array, hence the internal
error.
This patch fixes the problem by adding a size_check before trying
to print the dereferenced value. To perform this check, a function
that was previously specific to ada-lang.c (check_size) gets
exported, and renamed to something less prone to name collisions
(ada_ensure_varsize_limit).
gdb/ChangeLog:
* ada-lang.h (ada_ensure_varsize_limit): Declare.
* ada-lang.c (check_size): Remove advance declaration.
(ada_ensure_varsize_limit): Renames check_size.
Replace calls to check_size by calls to ada_ensure_varsize_limit
throughout.
* ada-valprint.c (ada_val_print_ref): Add call to
ada_ensure_varsize_limit. Add comment explaining why.
gdb/testsuite/ChangeLog:
* gdb.ada/str_uninit: New testcase.
The use of sprintf is discouraged in GDB. Use xsnprintf instead.
gdb/ChangeLog:
* utils.c (make_hex_string): Replace use of sprintf by use of
xsnprintf.
Tested on x86_64-linux.
gdb/ChangeLog:
* compile/compile-object-load.c (link_callbacks_multiple_definition)
(link_callbacks_warning, link_callbacks_einfo): Remove trailing
newline at end of warning message.
Tested on x86_64-linux.
This patch mostly aims at fixing a GDB build failure on 32bit Solaris
systems (Sparc and x86), due to a recent gnulib update adding the
readlink module. But it might also fix related issues when configuring
with --disable-largefile.
A side-effect of the gnulib readlink module addition is that it caused
largefile support to be added as well, and in particular
gnulib/import/m4/largefile.m4 introduced the following new #define in
gnulib's config.in:
| +/* Number of bits in a file offset, on hosts where this is settable. */
| +#undef _FILE_OFFSET_BITS
When defined to 64, it triggers an issue with procfs.h while trying
to build sparc-sol2-nat.c:
| #if !defined(_LP64) && _FILE_OFFSET_BITS == 64
| #error "Cannot use procfs in the large file compilation environment"
| #endif
As it turns out, this is a fairly familiar problem, and one of
the reasons behind ACX_LARGEFILE having been created. In that macro,
we have some code which disables largefile support on solaris hosts:
| sparc-*-solaris*|i[3-7]86-*-solaris*)
| changequote([,])dnl
| # On native 32bit sparc and ia32 solaris, large-file and procfs support
| # are mutually exclusive; and without procfs support, the bfd/ elf module
| # cannot provide certain routines such as elfcore_write_prpsinfo
| # or elfcore_write_prstatus. So unless the user explicitly requested
| # large-file support through the --enable-largefile switch, disable
| # large-file support in favor of procfs support.
| test "${target}" = "${host}" -a "x$plugins" = xno \
| && : ${enable_largefile="no"}
| ;;
But gnulib ignores this fact, and so tries to determine how to
enable large-file support irrespective of whether we want it or not.
This patch fixes the issue by passing --disable-largefile to gnulib's
configure when large-file support in GDB is disabled. This is done
by first enhancing ACX_CONFIGURE_DIR to allow us to pass extra
arguments to be passed to the configure command, and then by modifying
GDB's configure to pass --disable-largefile if large-file support
is disabled.
gdb/ChangeLog:
* acx_configure_dir.m4 (ACX_CONFIGURE_DIR): Add support for
new "EXTRA-ARGS" parameter.
* configure.ac: If large-file support is disabled in GDB,
pass --disable-largefile to ACX_CONFIGURE_DIR call for "gnulib".
* configure: Regenerate.
gdb/gdbserver/ChangeLog:
* configure.ac: If large-file support is disabled in GDBserver,
pass --disable-largefile to ACX_CONFIGURE_DIR call for "gnulib".
* configure: Regenerate.
Tested by rebuilding on sparc-solaris and x86_64-linux (with gdbserver).
This fixes the build failure on sparc-solaris. I also verified in
gnulib's config.log file that we pass --disable-largefile in the solaris
case, while we do not in the GNU/Linux case.
https://sourceware.org/bugzilla/show_bug.cgi?id=17642
Regression since:
commit 012370f681
Author: Tom Tromey <tromey@redhat.com>
Date: Thu May 8 11:26:44 2014 -0600
handle VLA in a struct or union
Bugreport:
Regression with gdb scripts for Linux kernel
https://sourceware.org/ml/gdb/2014-08/msg00127.html
That big change after "else" is just reindentation.
gdb/ChangeLog
2014-12-13 Jan Kratochvil <jan.kratochvil@redhat.com>
PR symtab/17642
* gdbtypes.c (resolve_dynamic_type_internal): Apply check_typedef to
TYPE if not TYPE_CODE_TYPEDEF.
gdb/testsuite/ChangeLog
2014-12-13 Jan Kratochvil <jan.kratochvil@redhat.com>
PR symtab/17642
* gdb.base/vla-stub-define.c: New file.
* gdb.base/vla-stub.c: New file.
* gdb.base/vla-stub.exp: New file.
GDB is currently broken on all SPARC targets when using GCC 4.9.
When trying to print any local variable:
(gdb) p x
can't compute CFA for this frame
This is related to the fact that the compiler now generates DWARF 4
debugging info by default, and in particular that it now emits
DW_OP_call_frame_cfa, which triggers a limitation in dwarf2_frame_cfa:
/* This restriction could be lifted if other unwinders are known to
compute the frame base in a way compatible with the DWARF
unwinder. */
if (!frame_unwinder_is (this_frame, &dwarf2_frame_unwind)
&& !frame_unwinder_is (this_frame, &dwarf2_tailcall_frame_unwind))
error (_("can't compute CFA for this frame"));
We couldn't append the dwarf2 unwinder to all SPARC targets because
it does not work properly with StackGhost:
https://www.sourceware.org/ml/gdb-patches/2014-07/msg00012.html
We also later discovered that using the DWARF2 unwinder means
using it for computing the function's return address, which
is buggy when it comes to functions returning a struct (where
the return address is saved-pc+12 instead of saved-pc+8).
This is because GCC is emitting the info about the return address
as %o7/%i7 instead of the actual return address. For functions
that have debugging info, we compensate by looking at the function's
return type and add the extra +4, but for function without debug
info, we're stuck.
EricB and I twisted the issue in all the directions we could think of,
and unfortunately couldn't find a way to make it work without
introduction one regression or another.
But, stepping back a little, just removing the restriction seems to work
well for us on all both sparc-elf and {sparc,sparc64}-solaris.
After reviewing the previous discussions about this test, I could
not figure out whether some unwinders were already known to have
incompatible CFAs or if the concern was purely theoretical:
https://www.sourceware.org/ml/gdb-patches/2009-06/msg00191.htmlhttps://www.sourceware.org/ml/gdb-patches/2009-07/msg00570.htmlhttps://www.sourceware.org/ml/gdb-patches/2009-09/msg00027.html
At the moment, we took the approach of trying it out, and see what
happens...
gdb/ChangeLog:
PR backtrace/16215:
* dwarf2-frame.c (dwarf2_frame_cfa): Remove the restriction
the frame unwinder must either be the dwarf2_frame_unwind
or the dwarf2_tailcall_frame_unwind. Verify that this_frame's
stack_addr is valid before calling get_frame_base. Throw
an error if not valid.
Tested on sparc-solaris and sparc-elf with AdaCore's testsuite
(the FSF testsuite crashes all of AdaCore's solaris machines).
Both allocate_value and value_of_variable are guaranteed to return non-NULL.
gdb/ChangeLog:
* valops.c (value_maybe_namespace_elt): Remove unnecessary test of
result != NULL.
Add missing function comments.
gdb/ChangeLog:
* psymtab.c (psym_map_symtabs_matching_filename): Renamed from
partial_map_symtabs_matching_filename. All uses updated.
(psym_find_pc_sect_compunit_symtab): Renamed from
find_pc_sect_compunit_symtab_from_partial. All uses updated.
Add function comment.
(psym_lookup_symbol): Renamed from lookup_symbol_aux_psymtabs.
All uses updated. Add function comment.
(psym_relocate): Renamed from relocate_psymtabs. All uses updated.
Add function comment.
(psym_find_last_source_symtab): Renamed from
find_last_source_symtab_from_partial. All uses updated.
Add function comment.
(psym_forget_cached_source_info): Renamed from
forget_cached_source_info_partial. All uses updated.
Add function comment.
(psym_print_stats): Renamed from print_psymtab_stats_for_objfile.
All uses updated. Add function comment.
(psym_dump): Renamed from dump_psymtabs_for_objfile. All uses
updated. Add function comment.
(psym_expand_symtabs_for_function): Renamed from
read_symtabs_for_function. All uses updated. Update function comment.
(psym_expand_all_symtabs): Renamed from expand_partial_symbol_tables.
All uses updated. Add function comment.
(psym_expand_symtabs_with_fullname): Renamed from
read_psymtabs_with_fullname. All uses updated. Add function comment.
(psym_map_symbol_filenames): Renamed from map_symbol_filenames_psymtab.
All uses updated. Add function comment.
(psym_map_matching_symbols): Renamed from map_matching_symbols_psymtab.
All uses updated.
(psym_expand_symtabs_matching): Renamed from
expand_symtabs_matching_via_partial. All uses updated.
Add function comment.
(psym_has_symbols): Renamed from objfile_has_psyms. All uses updated.
Add function comment.
This final patch adds the new "compile" command and subcommands, and
all the machinery needed to make it work.
A shared library supplied by gcc is used for all communications with
gcc. Types and most aspects of symbols are provided directly by gdb
to the compiler using this library.
gdb provides some information about the user's code using plain text.
Macros are emitted this way, and DWARF location expressions (and
bounds for VLA) are compiled to C code.
This hybrid approach was taken because, on the one hand, it is better
to provide global declarations and such on demand; but on the other
hand, for local variables, translating DWARF location expressions to C
was much simpler than exporting a full compiler API to gdb -- the same
result, only easier to implement, understand, and debug.
In the ordinary mode, the user's expression is wrapped in a dummy
function. After compilation, gdb inserts the resulting object code
into the inferior, then calls this function.
Access to local variables is provided by noting which registers are
used by location expressions, and passing a structure of register
values into the function. Writes to registers are supported by
copying out these values after the function returns.
This approach was taken so that we could eventually implement other
more interesting features based on this same infrastructure; for
example, we're planning to investigate inferior-side breakpoint
conditions.
gdb/ChangeLog
2014-12-12 Phil Muldoon <pmuldoon@redhat.com>
Jan Kratochvil <jan.kratochvil@redhat.com>
Tom Tromey <tromey@redhat.com>
* NEWS: Update.
* symtab.h (struct symbol_computed_ops) <generate_c_location>: New
field.
* p-lang.c (pascal_language_defn): Update.
* opencl-lang.c (opencl_language_defn): Update.
* objc-lang.c (objc_language_defn): Update.
* m2-lang.c (m2_language_defn): Update.
* language.h (struct language_defn) <la_get_compile_instance,
la_compute_program>: New fields.
* language.c (unknown_language_defn, auto_language_defn)
(local_language_defn): Update.
* jv-lang.c (java_language_defn): Update.
* go-lang.c (go_language_defn): Update.
* f-lang.c (f_language_defn): Update.
* dwarf2loc.h (dwarf2_compile_property_to_c): Declare.
* dwarf2loc.c (dwarf2_compile_property_to_c)
(locexpr_generate_c_location, loclist_generate_c_location): New
functions.
(dwarf2_locexpr_funcs, dwarf2_loclist_funcs): Update.
* defs.h (enum compile_i_scope_types): New.
(enum command_control_type) <compile_control>: New constant.
(struct command_line) <control_u>: New field.
* d-lang.c (d_language_defn): Update.
* compile/compile.c: New file.
* compile/compile-c-support.c: New file.
* compile/compile-c-symbols.c: New file.
* compile/compile-c-types.c: New file.
* compile/compile.h: New file.
* compile/compile-internal.h: New file.
* compile/compile-loc2c.c: New file.
* compile/compile-object-load.c: New file.
* compile/compile-object-load.h: New file.
* compile/compile-object-run.c: New file.
* compile/compile-object-run.h: New file.
* cli/cli-script.c (multi_line_command_p, print_command_lines)
(execute_control_command, process_next_line)
(recurse_read_control_structure): Handle compile_control.
* c-lang.h (c_get_compile_context, c_compute_program): Declare.
* c-lang.c (c_language_defn, cplus_language_defn)
(asm_language_defn, minimal_language_defn): Update.
* ada-lang.c (ada_language_defn): Update.
* Makefile.in (SUBDIR_GCC_COMPILE_OBS, SUBDIR_GCC_COMPILE_SRCS):
New variables.
(SFILES): Add SUBDIR_GCC_COMPILE_SRCS.
(HFILES_NO_SRCDIR): Add compile.h.
(COMMON_OBS): Add SUBDIR_GCC_COMPILE_OBS.
(INIT_FILES): Add SUBDIR_GCC_COMPILE_SRCS.
(compile.o, compile-c-types.o, compile-c-symbols.o)
(compile-object-load.o, compile-object-run.o, compile-loc2c.o)
(compile-c-support.o): New targets.
gdb/doc/ChangeLog
2014-12-12 Phil Muldoon <pmuldoon@redhat.com>
Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.texinfo (Altering): Update.
(Compiling and Injecting Code): New node.
gdb/testsuite/ChangeLog
2014-12-12 Phil Muldoon <pmuldoon@redhat.com>
Jan Kratochvil <jan.kratochvil@redhat.com>
Tom Tromey <tromey@redhat.com>
* configure.ac: Add gdb.compile/.
* configure: Regenerate.
* gdb.compile/Makefile.in: New file.
* gdb.compile/compile-ops.exp: New file.
* gdb.compile/compile-ops.c: New file.
* gdb.compile/compile-tls.c: New file.
* gdb.compile/compile-tls.exp: New file.
* gdb.compile/compile-constvar.S: New file.
* gdb.compile/compile-constvar.c: New file.
* gdb.compile/compile-mod.c: New file.
* gdb.compile/compile-nodebug.c: New file.
* gdb.compile/compile-setjmp-mod.c: New file.
* gdb.compile/compile-setjmp.c: New file.
* gdb.compile/compile-setjmp.exp: New file.
* gdb.compile/compile-shlib.c: New file.
* gdb.compile/compile.c: New file.
* gdb.compile/compile.exp: New file.
* lib/gdb.exp (skip_compile_feature_tests): New proc.
This adds s390_gcc_target_options, an implementation of the new
"gcc_target_options" gdbarch method. This was needed because the
default implementation of the method doesn't work properly for S390,
as this architecture needs "-m31" rather than "-m32".
gdb/ChangeLog
2014-12-12 Jan Kratochvil <jan.kratochvil@redhat.com>
* s390-linux-tdep.c (s390_gcc_target_options): New function.
(s390_gdbarch_init): Add it to gdbarch.
This implements the new gdbarch "infcall_mmap" method for Linux.
gdb/ChangeLog
2014-12-12 Jan Kratochvil <jan.kratochvil@redhat.com>
* linux-tdep.c: Include objfiles.h and infcall.h.
(GDB_MMAP_MAP_PRIVATE, GDB_MMAP_MAP_ANONYMOUS, linux_infcall_mmap): New
function.
(linux_init_abi): Add linux_infcall_mmap to gdbarch.
This exports a utility function, dwarf2_reg_to_regnum_or_error, that
was previously private to dwarf2loc.c.
gdb/ChangeLog
2014-12-12 Jan Kratochvil <jan.kratochvil@redhat.com>
* dwarf2loc.h (dwarf2_reg_to_regnum_or_error): Declare.
* dwarf2loc.c (dwarf2_reg_to_regnum_or_error): Rename from
translate_register. Now public.
(dwarf2_compile_expr_to_ax): Update.
This exports dwarf_expr_frame_base_1 so that other code can use it.
gdb/ChangeLog
2014-12-12 Tom Tromey <tromey@redhat.com>
Jan Kratochvil <jan.kratochvil@redhat.com>
* dwarf2loc.c (dwarf_expr_frame_base_1): Remove declaration.
(dwarf_expr_frame_base): Update caller.
(dwarf_expr_frame_base_1): Rename to ...
(func_get_frame_base_dwarf_block): ... this and make it public.
(dwarf2_compile_expr_to_ax, locexpr_describe_location_piece): Update
callers.
* dwarf2loc.h (func_get_frame_base_dwarf_block): New declaration.
This removes dwarf2_compile_expr_to_ax, replacing it with a utility
function that fetches the CFA data and adding the code to actually
compile to an agent expression directly into
dwarf2_compile_expr_to_ax. This refactoring lets a later patch reuse
the new dwarf2_fetch_cfa_info.
gdb/ChangeLog
2014-12-12 Tom Tromey <tromey@redhat.com>
* dwarf2loc.c (dwarf2_compile_expr_to_ax) <DW_OP_call_frame_cfa>:
Update.
* dwarf2-frame.c (dwarf2_fetch_cfa_info): New function, based on
dwarf2_compile_cfa_to_ax.
(dwarf2_compile_cfa_to_ax): Remove.
* dwarf2-frame.h (dwarf2_fetch_cfa_info): Declare.
(dwarf2_compile_cfa_to_ax): Remove.
This provides a variant of call_function_by_hand that allows the dummy
frame destructor to be set. This is used by the compiler code to
manage some resources when calling the gdb-generated inferior
function.
gdb/ChangeLog
2014-12-12 Jan Kratochvil <jan.kratochvil@redhat.com>
* infcall.h (call_function_by_hand_dummy): Declare.
* infcall.c (call_function_by_hand): Use
call_function_by_hand_dummy.
(call_function_by_hand_dummy): Rename from call_function_by_hand.
Add arguments. Register a destructor.
gdb has to inform libcc1.so of the target being used, so that the
correct compiler can be invoked. The compiler is invoked using the
GNU configury triplet prefix, e.g., "x86_64-unknown-linux-gnu-gcc".
In order for this to work we need to map the gdbarch to the GNU
configury triplet arch. In most cases these are identical; however,
the x86 family poses some problems, as the BFD arch names are quite
different from the GNU triplet names. So, we introduce a new gdbarch
method for this. A regular expression is used because there are
various valid values for the arch prefix in the triplet.
This patch also updates the osabi code to associate a regular
expression with the OS ABI. I have only added a concrete value for
Linux. Note that the "-gnu" part is optional, at least on Fedora it
is omitted from the installed GCC executable's name.
gdb/ChangeLog
2014-12-12 Tom Tromey <tromey@redhat.com>
Jan Kratochvil <jan.kratochvil@redhat.com>
* osabi.h (osabi_triplet_regexp): Declare.
* osabi.c (struct osabi_names): New.
(gdb_osabi_names): Change type to struct osabi_names. Update
values.
(gdbarch_osabi_name): Update.
(osabi_triplet_regexp): New function.
(osabi_from_tdesc_string, _initialize_gdb_osabi): Update.
* i386-tdep.c (i386_gnu_triplet_regexp): New method.
(i386_elf_init_abi, i386_go32_init_abi, i386_gdbarch_init): Call
set_gdbarch_gnu_triplet_regexp.
* gdbarch.sh (gnu_triplet_regexp): New method.
* gdbarch.c, gdbarch.h: Rebuild.
* arch-utils.h (default_gnu_triplet_regexp): Declare.
* arch-utils.c (default_gnu_triplet_regexp): New function.
The compiler needed two new gdbarch methods.
The infcall_mmap method allocates memory in the inferior.
This is used when inserting the object code.
The gcc_target_options method computes some arch-specific gcc options
to pass to the compiler. This is used to ensure that gcc generates
object code for the correct architecture.
gdb/ChangeLog
2014-12-12 Jan Kratochvil <jan.kratochvil@redhat.com>
* arch-utils.c (default_infcall_mmap)
(default_gcc_target_options): New functions.
* arch-utils.h (GDB_MMAP_PROT_READ, GDB_MMAP_PROT_WRITE)
(GDB_MMAP_PROT_EXEC): Define.
(default_infcall_mmap, default_gcc_target_options): Declare.
* gdbarch.h: Rebuild.
* gdbarch.c: Rebuild.
* gdbarch.sh (infcall_mmap, gcc_target_options): New methods.
The compiler code needed a hook into dummy frame destruction, so that
some state could be kept while the inferior call is made and then
destroyed when the inferior call finishes.
This patch adds an optional destructor to dummy frames and a new API
to access it.
gdb/ChangeLog
2014-12-12 Jan Kratochvil <jan.kratochvil@redhat.com>
* dummy-frame.c (struct dummy_frame) <dtor, dtor_data>: New
fields.
(pop_dummy_frame): Call the destructor if it exists.
(register_dummy_frame_dtor, find_dummy_frame_dtor): New
functions.
* dummy-frame.h (dummy_frame_dtor_ftype): New typedef.
(register_dummy_frame_dtor, find_dummy_frame_dtor): Declare.
There's seemingly no function to get the unqualified variant of a
type, so this patch adds one. This new function will be used in the
final patch.
gdb/ChangeLog
2014-12-12 Tom Tromey <tromey@redhat.com>
* gdbtypes.h (make_unqualified_type): Declare.
* gdbtypes.c (make_unqualified_type): New function.
This changes the DWARF assembler to allow comments in a location
expression, and also adds support for a few new opcodes I needed.
gdb/testsuite/ChangeLog
2014-12-12 Tom Tromey <tromey@redhat.com>
* lib/dwarf.exp (_location): Ignore blank lines. Allow comments.
Handle DW_OP_pick, DW_OP_skip, DW_OP_bra.
The gcc plugin is split into two parts. One part is an ordinary gcc
plugin. The other part is a shared library that is loaded by gdb.
This patch adds some files that define the interface exported by this
shared library to gdb. These files also define the internal API by
which the gdb- and gcc-sides communicate.
These files will be kept in sync between gcc and gdb like much of
include/.
The exported API has been intentionally kept very simple. In
particular only a single function is exported from the gdb-side
library; symbol visibility is used to hide everything else. This
exported symbol is a function which is called to return a structure
holding function pointers that gdb then uses. This structure is
versioned so that changes can be made without necessarily requiring a
simultaneous gdb upgrade.
Note that the C compiler API is broken out separately. This lets us
extend it to other GCC front ends as desired. We plan to investigate
C++ in the future.
include/ChangeLog
2014-12-12 Phil Muldoon <pmuldoon@redhat.com>
Jan Kratochvil <jan.kratochvil@redhat.com>
Tom Tromey <tromey@redhat.com>
* gcc-c-fe.def: New file.
* gcc-c-interface.h: New file.
* gcc-interface.h: New file.
This introduces a small helper function, ui_file_write_for_put. It is
a wrapper for ui_write that is suitable for passing directly to
ui_file_put.
This patch also updates one existing spot to use this new function.
gdb/ChangeLog
2014-12-12 Tom Tromey <tromey@redhat.com>
* ui-file.h (ui_file_write_for_put): Declare.
* ui-file.c (ui_file_write_for_put): New function.
* mi/mi-out.c (do_write): Remove.
(mi_out_put): Use ui_file_write_for_put.
* mips-tdep.h (MSYMBOL_TARGET_FLAG_MIPS16): New macro.
(MSYMBOL_TARGET_FLAG_MICROMIPS): Likewise.
* mips-tdep.c (mips_elf_make_msymbol_special): Use the new
macros.
(msymbol_is_mips, msymbol_is_mips16, msymbol_is_micromips):
Likewise.
Provide a new completion function for the argument of "info
registers", "info all-registers", and the "lr" command in dbx mode.
Without this patch the default symbol completer is used, which is more
confusing than helpful.
Also add a test for this new feature to "completion.exp": Determine
the target's available set of registers/reggroups and compare this to
the completion of "info registers ". For determining the available
registers involve the new "maint print user-registers" command.
gdb/ChangeLog:
* completer.c: Include "target.h", "reggroups.h", and
"user-regs.h".
(reg_or_group_completer): New.
* completer.h (reg_or_group_completer): Declare.
* infcmd.c (_initialize_infcmd): Set reg_or_group_completer for
the "info registers" and "info all-registers" commands and the
dbx-mode "lr" command.
gdb/testsuite/ChangeLog:
* gdb.base/completion.exp: Add test for completion of "info
registers ".
This adds a command for listing the "user" registers. So far GDB
offered no means of determining the set of user registers and omitted
them from all other register listings.
gdb/ChangeLog:
* user-regs.c: Include "arch-utils.h", "command.h", and
"cli/cli-cmds.h".
(maintenance_print_user_registers): New.
(_initialize_user_regs): Register new "maint print user-registers"
subcommand.
* NEWS: Mention new GDB command "maint print user-registers".
gdb/doc/ChangeLog:
* gdb.texinfo: Document "maint print user-registers".
1. Background information
The MIPS architecture, as originally designed and implemented in
mid-1980s has a uniform instruction word size that is 4 bytes, naturally
aligned. As such all MIPS instructions are located at addresses that
have their bits #1 and #0 set to zeroes, and any attempt to execute an
instruction from an address that has any of the two bits set to one
causes an address error exception. This may for example happen when a
jump-register instruction is executed whose register value used as the
jump target has any of these bits set.
Then in mid 1990s LSI sought a way to improve code density for their
TinyRISC family of MIPS cores and invented an alternatively encoded
instruction set in a joint effort with MIPS Technologies (then a
subsidiary of SGI). The new instruction set has been named the MIPS16
ASE (Application-Specific Extension) and uses a variable instruction
word size, which is 2 bytes (as the name of the ASE suggests) for most,
but there are a couple of exceptions that take 4 bytes, and then most of
the 2-byte instructions can be treated with a 2-byte extension prefix to
expand the range of the immediate operands used.
As a result instructions are no longer 4-byte aligned, instead they are
aligned to a multiple of 2. That left the bit #0 still unused for code
references, be it for the standard MIPS (i.e. as originally invented) or
for the MIPS16 instruction set, and based on that observation a clever
trick was invented that on one hand allowed the processor to be
seamlessly switched between the two instruction sets at any time at the
run time while on the other avoided the introduction of any special
control register to do that.
So it is the bit #0 of the instruction address that was chosen as the
selector and named the ISA bit. Any instruction executed at an even
address is interpreted as a standard MIPS instruction (the address still
has to have its bit #1 clear), any instruction executed at an odd
address is interpreted as a MIPS16 instruction.
To switch between modes ordinary jump instructions are used, such as
used for function calls and returns, specifically the bit #0 of the
source register used in jump-register instructions selects the execution
(ISA) mode for the following piece of code to be interpreted in.
Additionally new jump-immediate instructions were added that flipped the
ISA bit to select the opposite mode upon execution. They were
considered necessary to avoid the need to make register jumps in all
cases as the original jump-immediate instructions provided no way to
change the bit #0 at all.
This was all important for cases where standard MIPS and MIPS16 code had
to be mixed, either for compatibility with the existing binary code base
or to access resources not reachable from MIPS16 code (the MIPS16
instruction set only provides access to general-purpose registers, and
not for example floating-point unit registers or privileged coprocessor
0 registers) -- pieces of code in the opposite mode can be executed as
ordinary subroutine calls.
A similar approach has been more recently adopted for the MIPS16
replacement instruction set defined as the so called microMIPS ASE.
This is another instruction set encoding introduced to the MIPS
architecture. Just like the MIPS16 ASE, the microMIPS instruction set
uses a variable-length encoding, where each instruction takes a multiple
of 2 bytes. The ISA bit has been reused and for microMIPS-capable
processors selects between the standard MIPS and the microMIPS mode
instead.
2. Statement of the problem
To put it shortly, MIPS16 and microMIPS code pointers used by GDB are
different to these observed at the run time. This results in the same
expressions being evaluated producing different results in GDB and in
the program being debugged. Obviously it's the results obtained at the
run time that are correct (they define how the program behaves) and
therefore by definition the results obtained in GDB are incorrect.
A bit longer description will record that obviously at the run time the
ISA bit has to be set correctly (refer to background information above
if unsure why so) or the program will not run as expected. This is
recorded in all the executable file structures used at the run time: the
dynamic symbol table (but not always the static one!), the GOT, and
obviously in all the addresses embedded in code or data of the program
itself, calculated by applying the appropriate relocations at the static
link time.
While a program is being processed by GDB, the ISA bit is stripped off
from any code addresses, presumably to make them the same as the
respective raw memory byte address used by the processor to access the
instruction in the instruction fetch access cycle. This stripping is
actually performed outside GDB proper, in BFD, specifically
_bfd_mips_elf_symbol_processing (elfxx-mips.c, see the piece of code at
the very bottom of that function, starting with an: "If this is an
odd-valued function symbol, assume it's a MIPS16 or microMIPS one."
comment).
This function is also responsible for symbol table dumps made by
`objdump' too, so you'll never see the ISA bit reported there by that
tool, you need to use `readelf'.
This is however unlike what is ever done at the run time, the ISA bit
once present is never stripped off, for example a cast like this:
(short *) main
will not strip the ISA bit off and if the resulting pointer is intended
to be used to access instructions as data, for example for software
instruction decoding (like for fault recovery or emulation in a signal
handler) or for self-modifying code then the bit still has to be
stripped off by an explicit AND operation.
This is probably best illustrated with a simple real program example.
Let's consider the following simple program:
$ cat foobar.c
int __attribute__ ((mips16)) foo (void)
{
return 1;
}
int __attribute__ ((mips16)) bar (void)
{
return 2;
}
int __attribute__ ((nomips16)) foo32 (void)
{
return 3;
}
int (*foo32p) (void) = foo32;
int (*foop) (void) = foo;
int fooi = (int) foo;
int
main (void)
{
return foop ();
}
$
This is plain C with no odd tricks, except from the instruction mode
attributes. They are not necessary to trigger this problem, I just put
them here so that the program can be contained in a single source file
and to make it obvious which function is MIPS16 code and which is not.
Let's try it with Linux, so that everyone can repeat this experiment:
$ mips-linux-gnu-gcc -mips16 -g -O2 -o foobar foobar.c
$
Let's have a look at some interesting symbols:
$ mips-linux-gnu-readelf -s foobar | egrep 'table|foo|bar'
Symbol table '.dynsym' contains 7 entries:
Symbol table '.symtab' contains 95 entries:
55: 00000000 0 FILE LOCAL DEFAULT ABS foobar.c
66: 0040068c 4 FUNC GLOBAL DEFAULT [MIPS16] 12 bar
68: 00410848 4 OBJECT GLOBAL DEFAULT 21 foo32p
70: 00410844 4 OBJECT GLOBAL DEFAULT 21 foop
78: 00400684 8 FUNC GLOBAL DEFAULT 12 foo32
80: 00400680 4 FUNC GLOBAL DEFAULT [MIPS16] 12 foo
88: 00410840 4 OBJECT GLOBAL DEFAULT 21 fooi
$
Hmm, no sight of the ISA bit, but notice how foo and bar (but not
foo32!) have been marked as MIPS16 functions (ELF symbol structure's
`st_other' field is used for that).
So let's try to run and poke at this program with GDB. I'll be using a
native system for simplicity (I'll be using ellipses here and there to
remove unrelated clutter):
$ ./foobar
$ echo $?
1
$
So far, so good.
$ gdb ./foobar
[...]
(gdb) break main
Breakpoint 1 at 0x400490: file foobar.c, line 23.
(gdb) run
Starting program: .../foobar
Breakpoint 1, main () at foobar.c:23
23 return foop ();
(gdb)
Yay, it worked! OK, so let's poke at it:
(gdb) print main
$1 = {int (void)} 0x400490 <main>
(gdb) print foo32
$2 = {int (void)} 0x400684 <foo32>
(gdb) print foo32p
$3 = (int (*)(void)) 0x400684 <foo32>
(gdb) print bar
$4 = {int (void)} 0x40068c <bar>
(gdb) print foo
$5 = {int (void)} 0x400680 <foo>
(gdb) print foop
$6 = (int (*)(void)) 0x400681 <foo>
(gdb)
A-ha! Here's the difference and finally the ISA bit!
(gdb) print /x fooi
$7 = 0x400681
(gdb) p/x $pc
p/x $pc
$8 = 0x400491
(gdb)
And here as well...
(gdb) advance foo
foo () at foobar.c:4
4 }
(gdb) disassemble
Dump of assembler code for function foo:
0x00400680 <+0>: jr ra
0x00400682 <+2>: li v0,1
End of assembler dump.
(gdb) finish
Run till exit from #0 foo () at foobar.c:4
main () at foobar.c:24
24 }
Value returned is $9 = 1
(gdb) continue
Continuing.
[Inferior 1 (process 14103) exited with code 01]
(gdb)
So let's be a bit inquisitive...
(gdb) run
Starting program: .../foobar
Breakpoint 1, main () at foobar.c:23
23 return foop ();
(gdb)
Actually we do not like to run foo here at all. Let's run bar instead!
(gdb) set foop = bar
(gdb) print foop
$10 = (int (*)(void)) 0x40068c <bar>
(gdb)
Hmm, no ISA bit. Is it going to work?
(gdb) advance bar
bar () at foobar.c:9
9 }
(gdb) p/x $pc
$11 = 0x40068c
(gdb) disassemble
Dump of assembler code for function bar:
=> 0x0040068c <+0>: jr ra
0x0040068e <+2>: li v0,2
End of assembler dump.
(gdb) finish
Run till exit from #0 bar () at foobar.c:9
Program received signal SIGILL, Illegal instruction.
bar () at foobar.c:9
9 }
(gdb)
Oops!
(gdb) p/x $pc
$12 = 0x40068c
(gdb)
We're still there!
(gdb) continue
Continuing.
Program terminated with signal SIGILL, Illegal instruction.
The program no longer exists.
(gdb)
So let's try something else:
(gdb) run
Starting program: .../foobar
Breakpoint 1, main () at foobar.c:23
23 return foop ();
(gdb) set foop = foo
(gdb) advance foo
foo () at foobar.c:4
4 }
(gdb) disassemble
Dump of assembler code for function foo:
=> 0x00400680 <+0>: jr ra
0x00400682 <+2>: li v0,1
End of assembler dump.
(gdb) finish
Run till exit from #0 foo () at foobar.c:4
Program received signal SIGILL, Illegal instruction.
foo () at foobar.c:4
4 }
(gdb) continue
Continuing.
Program terminated with signal SIGILL, Illegal instruction.
The program no longer exists.
(gdb)
The same problem!
(gdb) run
Starting program:
/net/build2-lucid-cs/scratch/macro/mips-linux-fsf-gcc/isa-bit/foobar
Breakpoint 1, main () at foobar.c:23
23 return foop ();
(gdb) set foop = foo32
(gdb) advance foo32
foo32 () at foobar.c:14
14 }
(gdb) disassemble
Dump of assembler code for function foo32:
=> 0x00400684 <+0>: jr ra
0x00400688 <+4>: li v0,3
End of assembler dump.
(gdb) finish
Run till exit from #0 foo32 () at foobar.c:14
main () at foobar.c:24
24 }
Value returned is $14 = 3
(gdb) continue
Continuing.
[Inferior 1 (process 14113) exited with code 03]
(gdb)
That did work though, so it's the ISA bit only!
(gdb) quit
Enough!
That's the tip of the iceberg only though. So let's rebuild the
executable with some dynamic symbols:
$ mips-linux-gnu-gcc -mips16 -Wl,--export-dynamic -g -O2 -o foobar-dyn foobar.c
$ mips-linux-gnu-readelf -s foobar-dyn | egrep 'table|foo|bar'
Symbol table '.dynsym' contains 32 entries:
6: 004009cd 4 FUNC GLOBAL DEFAULT 12 bar
8: 00410b88 4 OBJECT GLOBAL DEFAULT 21 foo32p
9: 00410b84 4 OBJECT GLOBAL DEFAULT 21 foop
15: 004009c4 8 FUNC GLOBAL DEFAULT 12 foo32
17: 004009c1 4 FUNC GLOBAL DEFAULT 12 foo
25: 00410b80 4 OBJECT GLOBAL DEFAULT 21 fooi
Symbol table '.symtab' contains 95 entries:
55: 00000000 0 FILE LOCAL DEFAULT ABS foobar.c
69: 004009cd 4 FUNC GLOBAL DEFAULT 12 bar
71: 00410b88 4 OBJECT GLOBAL DEFAULT 21 foo32p
72: 00410b84 4 OBJECT GLOBAL DEFAULT 21 foop
79: 004009c4 8 FUNC GLOBAL DEFAULT 12 foo32
81: 004009c1 4 FUNC GLOBAL DEFAULT 12 foo
89: 00410b80 4 OBJECT GLOBAL DEFAULT 21 fooi
$
OK, now the ISA bit is there for a change, but the MIPS16 `st_other'
attribute gone, hmm... What does `objdump' do then:
$ mips-linux-gnu-objdump -Tt foobar-dyn | egrep 'SYMBOL|foo|bar'
foobar-dyn: file format elf32-tradbigmips
SYMBOL TABLE:
00000000 l df *ABS* 00000000 foobar.c
004009cc g F .text 00000004 0xf0 bar
00410b88 g O .data 00000004 foo32p
00410b84 g O .data 00000004 foop
004009c4 g F .text 00000008 foo32
004009c0 g F .text 00000004 0xf0 foo
00410b80 g O .data 00000004 fooi
DYNAMIC SYMBOL TABLE:
004009cc g DF .text 00000004 Base 0xf0 bar
00410b88 g DO .data 00000004 Base foo32p
00410b84 g DO .data 00000004 Base foop
004009c4 g DF .text 00000008 Base foo32
004009c0 g DF .text 00000004 Base 0xf0 foo
00410b80 g DO .data 00000004 Base fooi
$
Hmm, the attribute (0xf0, printed raw) is back, and the ISA bit gone
again.
Let's have a look at some DWARF-2 records GDB uses (I'll be stripping
off a lot here for brevity) -- debug info:
$ mips-linux-gnu-readelf -wi foobar
Contents of the .debug_info section:
[...]
Compilation Unit @ offset 0x88:
Length: 0xbb (32-bit)
Version: 4
Abbrev Offset: 62
Pointer Size: 4
<0><93>: Abbrev Number: 1 (DW_TAG_compile_unit)
<94> DW_AT_producer : (indirect string, offset: 0x19e): GNU C 4.8.0 20120513 (experimental) -meb -mips16 -march=mips32r2 -mhard-float -mllsc -mplt -mno-synci -mno-shared -mabi=32 -g -O2
<98> DW_AT_language : 1 (ANSI C)
<99> DW_AT_name : (indirect string, offset: 0x190): foobar.c
<9d> DW_AT_comp_dir : (indirect string, offset: 0x225): [...]
<a1> DW_AT_ranges : 0x0
<a5> DW_AT_low_pc : 0x0
<a9> DW_AT_stmt_list : 0x27
<1><ad>: Abbrev Number: 2 (DW_TAG_subprogram)
<ae> DW_AT_external : 1
<ae> DW_AT_name : foo
<b2> DW_AT_decl_file : 1
<b3> DW_AT_decl_line : 1
<b4> DW_AT_prototyped : 1
<b4> DW_AT_type : <0xc2>
<b8> DW_AT_low_pc : 0x400680
<bc> DW_AT_high_pc : 0x400684
<c0> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<c2> DW_AT_GNU_all_call_sites: 1
<1><c2>: Abbrev Number: 3 (DW_TAG_base_type)
<c3> DW_AT_byte_size : 4
<c4> DW_AT_encoding : 5 (signed)
<c5> DW_AT_name : int
<1><c9>: Abbrev Number: 4 (DW_TAG_subprogram)
<ca> DW_AT_external : 1
<ca> DW_AT_name : (indirect string, offset: 0x18a): foo32
<ce> DW_AT_decl_file : 1
<cf> DW_AT_decl_line : 11
<d0> DW_AT_prototyped : 1
<d0> DW_AT_type : <0xc2>
<d4> DW_AT_low_pc : 0x400684
<d8> DW_AT_high_pc : 0x40068c
<dc> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<de> DW_AT_GNU_all_call_sites: 1
<1><de>: Abbrev Number: 2 (DW_TAG_subprogram)
<df> DW_AT_external : 1
<df> DW_AT_name : bar
<e3> DW_AT_decl_file : 1
<e4> DW_AT_decl_line : 6
<e5> DW_AT_prototyped : 1
<e5> DW_AT_type : <0xc2>
<e9> DW_AT_low_pc : 0x40068c
<ed> DW_AT_high_pc : 0x400690
<f1> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<f3> DW_AT_GNU_all_call_sites: 1
<1><f3>: Abbrev Number: 5 (DW_TAG_subprogram)
<f4> DW_AT_external : 1
<f4> DW_AT_name : (indirect string, offset: 0x199): main
<f8> DW_AT_decl_file : 1
<f9> DW_AT_decl_line : 21
<fa> DW_AT_prototyped : 1
<fa> DW_AT_type : <0xc2>
<fe> DW_AT_low_pc : 0x400490
<102> DW_AT_high_pc : 0x4004a4
<106> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<108> DW_AT_GNU_all_tail_call_sites: 1
[...]
$
-- no sign of the ISA bit anywhere -- frame info:
$ mips-linux-gnu-readelf -wf foobar
[...]
Contents of the .debug_frame section:
00000000 0000000c ffffffff CIE
Version: 1
Augmentation: ""
Code alignment factor: 1
Data alignment factor: -4
Return address column: 31
DW_CFA_def_cfa_register: r29
DW_CFA_nop
00000010 0000000c 00000000 FDE cie=00000000 pc=00400680..00400684
00000020 0000000c 00000000 FDE cie=00000000 pc=00400684..0040068c
00000030 0000000c 00000000 FDE cie=00000000 pc=0040068c..00400690
00000040 00000018 00000000 FDE cie=00000000 pc=00400490..004004a4
DW_CFA_advance_loc: 6 to 00400496
DW_CFA_def_cfa_offset: 32
DW_CFA_offset: r31 at cfa-4
DW_CFA_advance_loc: 6 to 0040049c
DW_CFA_restore: r31
DW_CFA_def_cfa_offset: 0
DW_CFA_nop
DW_CFA_nop
DW_CFA_nop
[...]
$
-- no sign of the ISA bit anywhere -- range info (GDB doesn't use arange):
$ mips-linux-gnu-readelf -wR foobar
Contents of the .debug_ranges section:
Offset Begin End
00000000 00400680 00400690
00000000 00400490 004004a4
00000000 <End of list>
$
-- no sign of the ISA bit anywhere -- line info:
$ mips-linux-gnu-readelf -wl foobar
Raw dump of debug contents of section .debug_line:
[...]
Offset: 0x27
Length: 78
DWARF Version: 2
Prologue Length: 31
Minimum Instruction Length: 1
Initial value of 'is_stmt': 1
Line Base: -5
Line Range: 14
Opcode Base: 13
Opcodes:
Opcode 1 has 0 args
Opcode 2 has 1 args
Opcode 3 has 1 args
Opcode 4 has 1 args
Opcode 5 has 1 args
Opcode 6 has 0 args
Opcode 7 has 0 args
Opcode 8 has 0 args
Opcode 9 has 1 args
Opcode 10 has 0 args
Opcode 11 has 0 args
Opcode 12 has 1 args
The Directory Table is empty.
The File Name Table:
Entry Dir Time Size Name
1 0 0 0 foobar.c
Line Number Statements:
Extended opcode 2: set Address to 0x400681
Special opcode 6: advance Address by 0 to 0x400681 and Line by 1 to 2
Special opcode 7: advance Address by 0 to 0x400681 and Line by 2 to 4
Special opcode 55: advance Address by 3 to 0x400684 and Line by 8 to 12
Special opcode 7: advance Address by 0 to 0x400684 and Line by 2 to 14
Advance Line by -7 to 7
Special opcode 131: advance Address by 9 to 0x40068d and Line by 0 to 7
Special opcode 7: advance Address by 0 to 0x40068d and Line by 2 to 9
Advance PC by 3 to 0x400690
Extended opcode 1: End of Sequence
Extended opcode 2: set Address to 0x400491
Advance Line by 21 to 22
Copy
Special opcode 6: advance Address by 0 to 0x400491 and Line by 1 to 23
Special opcode 60: advance Address by 4 to 0x400495 and Line by -1 to 22
Special opcode 34: advance Address by 2 to 0x400497 and Line by 1 to 23
Special opcode 62: advance Address by 4 to 0x40049b and Line by 1 to 24
Special opcode 32: advance Address by 2 to 0x40049d and Line by -1 to 23
Special opcode 6: advance Address by 0 to 0x40049d and Line by 1 to 24
Advance PC by 7 to 0x4004a4
Extended opcode 1: End of Sequence
[...]
-- a-ha, the ISA bit is there! However it's not always right for some
reason, I don't have a small test case to show it, but here's an excerpt
from MIPS16 libc, a prologue of a function:
00019630 <__libc_init_first>:
19630: e8a0 jrc ra
19632: 6500 nop
00019634 <_init>:
19634: f000 6a11 li v0,17
19638: f7d8 0b08 la v1,15e00 <_DYNAMIC+0x15c54>
1963c: f400 3240 sll v0,16
19640: e269 addu v0,v1
19642: 659a move gp,v0
19644: 64f6 save 48,ra,s0-s1
19646: 671c move s0,gp
19648: d204 sw v0,16(sp)
1964a: f352 984c lw v0,-27828(s0)
1964e: 6724 move s1,a0
and the corresponding DWARF-2 line info:
Line Number Statements:
Extended opcode 2: set Address to 0x19631
Advance Line by 44 to 45
Copy
Special opcode 8: advance Address by 0 to 0x19631 and Line by 3 to 48
Special opcode 66: advance Address by 4 to 0x19635 and Line by 5 to 53
Advance PC by constant 17 to 0x19646
Special opcode 25: advance Address by 1 to 0x19647 and Line by 6 to 59
Advance Line by -6 to 53
Special opcode 33: advance Address by 2 to 0x19649 and Line by 0 to 53
Special opcode 39: advance Address by 2 to 0x1964b and Line by 6 to 59
Advance Line by -6 to 53
Special opcode 61: advance Address by 4 to 0x1964f and Line by 0 to 53
-- see that "Advance PC by constant 17" there? It clears the ISA bit,
however code at 0x19646 is not standard MIPS code at all. For some
reason the constant is always 17, I've never seen DW_LNS_const_add_pc
used with any other value -- is that a binutils bug or what?
3. Solution:
I think we should retain the value of the ISA bit in code references,
that is effectively treat them as cookies as they indeed are (although
trivially calculated) rather than raw memory byte addresses.
In a perfect world both the static symbol table and the respective
DWARF-2 records should be fixed to include the ISA bit in all the cases.
I think however that this is infeasible.
All the uses of `_bfd_mips_elf_symbol_processing' can not necessarily be
tracked down. This function is used by `elf_slurp_symbol_table' that in
turn is used by `bfd_canonicalize_symtab' and
`bfd_canonicalize_dynamic_symtab', which are public interfaces.
Similarly DWARF-2 records are used outside GDB, one notable if a bit
questionable is the exception unwinder (libgcc/unwind-dw2.c) -- I have
identified at least bits in `execute_cfa_program' and
`uw_frame_state_for', both around the calls to `_Unwind_IsSignalFrame',
that would need an update as they effectively flip the ISA bit freely;
see also the comment about MASK_RETURN_ADDR in gcc/config/mips/mips.h.
But there may be more places. Any change in how DWARF-2 records are
produced would require an update there and would cause compatibility
problems with libgcc.a binaries already distributed; given that this is
a static library a complex change involving function renames would
likely be required.
I propose therefore to accept the existing inconsistencies and deal with
them entirely within GDB. I have figured out that the ISA bit lost in
various places can still be recovered as long as we have symbol
information -- that'll have the `st_other' attribute correctly set to
one of standard MIPS/MIPS16/microMIPS encoding.
Here's the resulting change. It adds a couple of new `gdbarch' hooks,
one to update symbol information with the ISA bit lost in
`_bfd_mips_elf_symbol_processing', and two other ones to adjust DWARF-2
records as they're processed. The ISA bit is set in each address
handled according to information retrieved from the symbol table for the
symbol spanning the address if any; limits are adjusted based on the
address they point to related to the respective base address.
Additionally minimal symbol information has to be adjusted accordingly
in its gdbarch hook.
With these changes in place some complications with ISA bit juggling in
the PC that never fully worked can be removed from the MIPS backend.
Conversely, the generic dynamic linker event special breakpoint symbol
handler has to be updated to call the minimal symbol gdbarch hook to
record that the symbol is a MIPS16 or microMIPS address if applicable or
the breakpoint will be set at the wrong address and either fail to work
or cause SIGTRAPs (this is because the symbol is handled early on and
bypasses regular symbol processing).
4. Results obtained
The change fixes the example above -- to repeat only the crucial steps:
(gdb) break main
Breakpoint 1 at 0x400491: file foobar.c, line 23.
(gdb) run
Starting program: .../foobar
Breakpoint 1, main () at foobar.c:23
23 return foop ();
(gdb) print foo
$1 = {int (void)} 0x400681 <foo>
(gdb) set foop = bar
(gdb) advance bar
bar () at foobar.c:9
9 }
(gdb) disassemble
Dump of assembler code for function bar:
=> 0x0040068d <+0>: jr ra
0x0040068f <+2>: li v0,2
End of assembler dump.
(gdb) finish
Run till exit from #0 bar () at foobar.c:9
main () at foobar.c:24
24 }
Value returned is $2 = 2
(gdb) continue
Continuing.
[Inferior 1 (process 14128) exited with code 02]
(gdb)
-- excellent!
The change removes about 90 failures per MIPS16 multilib in mips-sde-elf
testing too, results for MIPS16 are now similar to that for standard
MIPS; microMIPS results are a bit worse because of host-I/O problems in
QEMU used instead of MIPSsim for microMIPS testing only:
=== gdb Summary ===
# of expected passes 14299
# of unexpected failures 187
# of expected failures 56
# of known failures 58
# of unresolved testcases 11
# of untested testcases 52
# of unsupported tests 174
MIPS16:
=== gdb Summary ===
# of expected passes 14298
# of unexpected failures 187
# of unexpected successes 2
# of expected failures 54
# of known failures 58
# of unresolved testcases 12
# of untested testcases 52
# of unsupported tests 174
microMIPS:
=== gdb Summary ===
# of expected passes 14149
# of unexpected failures 201
# of unexpected successes 2
# of expected failures 54
# of known failures 58
# of unresolved testcases 7
# of untested testcases 53
# of unsupported tests 175
2014-12-12 Maciej W. Rozycki <macro@codesourcery.com>
Maciej W. Rozycki <macro@mips.com>
Pedro Alves <pedro@codesourcery.com>
gdb/
* gdbarch.sh (elf_make_msymbol_special): Change type to `F',
remove `predefault' and `invalid_p' initializers.
(make_symbol_special): New architecture method.
(adjust_dwarf2_addr, adjust_dwarf2_line): Likewise.
(objfile, symbol): New declarations.
* arch-utils.h (default_elf_make_msymbol_special): Remove
prototype.
(default_make_symbol_special): New prototype.
(default_adjust_dwarf2_addr): Likewise.
(default_adjust_dwarf2_line): Likewise.
* mips-tdep.h (mips_unmake_compact_addr): New prototype.
* arch-utils.c (default_elf_make_msymbol_special): Remove
function.
(default_make_symbol_special): New function.
(default_adjust_dwarf2_addr): Likewise.
(default_adjust_dwarf2_line): Likewise.
* dwarf2-frame.c (decode_frame_entry_1): Call
`gdbarch_adjust_dwarf2_addr'.
* dwarf2loc.c (dwarf2_find_location_expression): Likewise.
* dwarf2read.c (create_addrmap_from_index): Likewise.
(process_psymtab_comp_unit_reader): Likewise.
(add_partial_symbol): Likewise.
(add_partial_subprogram): Likewise.
(process_full_comp_unit): Likewise.
(read_file_scope): Likewise.
(read_func_scope): Likewise. Call `gdbarch_make_symbol_special'.
(read_lexical_block_scope): Call `gdbarch_adjust_dwarf2_addr'.
(read_call_site_scope): Likewise.
(dwarf2_ranges_read): Likewise.
(dwarf2_record_block_ranges): Likewise.
(read_attribute_value): Likewise.
(dwarf_decode_lines_1): Call `gdbarch_adjust_dwarf2_line'.
(new_symbol_full): Call `gdbarch_adjust_dwarf2_addr'.
* elfread.c (elf_symtab_read): Don't call
`gdbarch_elf_make_msymbol_special' if unset.
* mips-linux-tdep.c (micromips_linux_sigframe_validate): Strip
the ISA bit from the PC.
* mips-tdep.c (mips_unmake_compact_addr): New function.
(mips_elf_make_msymbol_special): Set the ISA bit in the symbol's
address appropriately.
(mips_make_symbol_special): New function.
(mips_pc_is_mips): Set the ISA bit before symbol lookup.
(mips_pc_is_mips16): Likewise.
(mips_pc_is_micromips): Likewise.
(mips_pc_isa): Likewise.
(mips_adjust_dwarf2_addr): New function.
(mips_adjust_dwarf2_line): Likewise.
(mips_read_pc, mips_unwind_pc): Keep the ISA bit.
(mips_addr_bits_remove): Likewise.
(mips_skip_trampoline_code): Likewise.
(mips_write_pc): Don't set the ISA bit.
(mips_eabi_push_dummy_call): Likewise.
(mips_o64_push_dummy_call): Likewise.
(mips_gdbarch_init): Install `mips_make_symbol_special',
`mips_adjust_dwarf2_addr' and `mips_adjust_dwarf2_line' gdbarch
handlers.
* solib.c (gdb_bfd_lookup_symbol_from_symtab): Get
target-specific symbol address adjustments.
* gdbarch.h: Regenerate.
* gdbarch.c: Regenerate.
2014-12-12 Maciej W. Rozycki <macro@codesourcery.com>
gdb/testsuite/
* gdb.base/func-ptrs.c: New file.
* gdb.base/func-ptrs.exp: New file.
This makes gas .cfi output to .debug_frame match register numbering
emitted by gcc. md_reg_eh_frame_to_debug_frame follows the ABI,
targets not using it, notably Linux, don't.
* config/tc-ppc.h (md_reg_eh_frame_to_debug_frame): Match current
gcc behaviour.
* config/te-aix.h: New file.
* configure.tgt: Use em=aix for powerpc-aix.
This makes gdbserver actually provide values for the TDB registers
when the inferior was stopped in a transaction. The change in
linux-low.c is needed to suppress the warning for an unavailable TDB.
The test case 's390-tdbregs.exp' passes with this patch and fails
without.
gdb/gdbserver/ChangeLog:
* linux-low.c (regsets_fetch_inferior_registers): Suppress the
warning upon ENODATA from ptrace.
* linux-s390-low.c (s390_store_tdb): New.
(s390_regsets): Add regset for NT_S390_TDB.
For GNU/Linux targets using the regsets interface, this change
supports regsets that can be read but not written. The S390 "last
break" regset is an example. So far it had been defined with
regset->set_request == PTRACE_GETREGSET, such that the respective
ptrace call does not cause any harm. Now we just skip the whole
read/modify/write sequence for regsets that do not define a
fill_function.
gdb/gdbserver/ChangeLog:
* linux-low.c (regsets_store_inferior_registers): Skip regsets
without a fill_function.
* linux-s390-low.c (s390_fill_last_break): Remove.
(s390_regsets): Set fill_function to NULL for NT_S390_LAST_BREAK.
(s390_arch_setup): Use regset's size instead of fill_function for
loop end condition.
When fetch_inferior_registers does not update all registers, this
patch assures that no stale register values remain in the register
cache. On Linux platforms using the regsets interface, when one of
the ptrace calls used for fetching the register values returns an
error, this patch also avoids copying the random data returned from
ptrace into the register cache. All unfetched registers are marked
"unavailable" instead.
gdb/gdbserver/ChangeLog:
* linux-low.c (regsets_fetch_inferior_registers): Do not invoke
the regset's store function when ptrace returned an error.
* regcache.c (get_thread_regcache): Invalidate register cache
before fetching inferior's registers.
Simon Marchi
H.J. Lu
Jason Merrill
Joel Brobecker
Catalin Udma
GDB Administrator
Doug Evans
Jan Kratochvil
Tom Tromey
Doug Evans
Maciej W. Rozycki
Andreas Arnez
Anthony Green
Alan Modra