I stumbled upon a few comments that I think are outdated.
Comment for elfread.c (elf_symfile_init): As far as history goes in git,
I don't see anything related to that.
Comment for elfread.c (elf_symfile_read): References a parameter that was
removed in 1999.
Comment for struct sym_fns/sym_offsets: References a parameter that was
changed in 1999.
gdb/ChangeLog:
* elfread.c (elf_symfile_init): Remove stale comment.
(elf_symfile_read): Same.
* symfile.h (struct sym_fns): Same.
This patch is the V2. V1 can be found in
https://sourceware.org/ml/gdb-patches/2012-05/msg00938.html
V2 is to address Joel's comment
<https://sourceware.org/ml/gdb-patches/2012-06/msg00289.html> about
keeping dumping floating point registers. Additionally, command
'info float' prints bits on nan2008 and abs2008.
------------------------------------------------------------------
The change below provides a MIPS-specific handler for the:
(gdb) info float
command. It provides information about the FPU type available (if any),
the FPU register width, and decodes the CP1 Floating Point Control and
Status Register (FCSR):
(gdb) print /x $fsr
$1 = 0xff83ffff
(gdb) info float
fpu type: double-precision
reg size: 32 bits
cond : 0 1 2 3 4 5 6 7
cause : inexact uflow oflow div0 inval unimp
mask : inexact uflow oflow div0 inval
flags : inexact uflow oflow div0 inval
rounding: -inf
flush : zero
One point to note about CP1.FCSR are the non-standard Flush-to-Nearest
and Flush-Override bits. They are not a part of the MIPS architecture and
take two positions reserved for an implementation-dependent use in the
architecture. They are present in all the FPU implementations made by
MIPS Technologies since the spin-off from SGI.
I haven't been able to track down a single other MIPS FPU implementation
that would make any use of these bits and they are required to be
hardwired to zero by the architecture specification if unimplemented.
Therefore I think it makes sense to report them in the current way.
GDB has no guaranteed access to the CP0 Processor Identification (PRId)
register to validate this feature properly and the ID information stored
in the CP1 Floating Point Implementation Register (FIR) is from my
experience not reliable enough (there's no Company ID available there for
once unlike in CP0.PRId and Processor ID is not guaranteed to be unique).
As a side note we should probably dump CP1.FIR information as well, as
there's useful stuff indicating some FPU features there. That's material
for another change however.
gdb/
2014-12-18 Nigel Stephens <nigel@mips.com>
Maciej W. Rozycki <macro@codesourcery.com>
* mips-tdep.c (print_fpu_flags): New function.
(mips_print_float_info): Likewise.
(mips_gdbarch_init): Install mips_print_float_info as gdbarch
print_float_info routine.
gdb/testsuite/
2014-12-18 Nigel Stephens <nigel@mips.com>
Maciej W. Rozycki <macro@codesourcery.com>
* gdb.base/float.exp: Handle the new output from "info float" on
MIPS targets.
This patch is to change print_float_info gdbarch method for the
following two reasons,
1. we want to add a default implementation of print_float_info to
dump the float pointer registers. It can be reused by backend to
print something more than float point registers.
2. we want to simplify the caller of print_float_info,
infcmd.c:print_float_info.
gdb:
2014-12-18 Yao Qi <yao@codesourcery.com>
* gdbarch.sh (print_float_info): Change its type from 'M' to 'm'.
* gdbarch.c: Re-generated.
* gdbarch.h: Likewise.
* infcmd.c (default_print_float_info): New function.
(print_float_info): Removed. Move code to
default_print_float_info.
(float_info): Adjust to call gdbarch_print_float_info.
* inferior.h (default_print_float_info): Declare it.
In infcmd.c:print_float_info, if the architecture doesn't have gdbarch
method print_float_info implemented and doesn't float reggroup, GDB
will prints "No floating-point info available for this processor."
The h8300 port doesn't have float registers, and don't need to
implement print_float_info. This patch is to remove it.
gdb:
2014-12-18 Yao Qi <yao@codesourcery.com>
* h8300-tdep.c (h8300_print_float_info): Remove.
(h8300_gdbarch_init): Remove the call to
set_gdbarch_print_float_info.
On Sun, 14 Dec 2014 07:00:28 +0100, Yao Qi wrote:
The build on mingw host is broken because mingw has no mkdtemp.
../../../git/gdb/compile/compile.c: In function 'get_compile_file_tempdir':
../../../git/gdb/compile/compile.c:194:3: error: implicit declaration of function 'mkdtemp' [-Werror=implicit-function-declaration]
tempdir_name = mkdtemp (tname);
^
../../../git/gdb/compile/compile.c:194:16: error: assignment makes pointer from integer without a cast [-Werror]
tempdir_name = mkdtemp (tname);
^
cc1: all warnings being treated as errors
In the end I have managed to test it by Wine myself:
$ wine build_win32/gdb/gdb.exe -q build_win32/gdb/gdb.exe -ex start -ex 'compile code 1' -ex 'set confirm no' -ex quit
[...]
Temporary breakpoint 1, main (argc=1, argv=0x241418) at ../../gdb/gdb.c:29
29 args.argc = argc;
Could not load libcc1.so: Module not found.
Even if it managed to load libcc1.so (it needs host-dependent name libcc1.dll)
then it would soon end up at least on:
default_infcall_mmap:
error (_("This target does not support inferior memory allocation by mmap."));
As currently there is only:
linux-tdep.c:
set_gdbarch_infcall_mmap (gdbarch, linux_infcall_mmap);
While one could debug Linux targets from MS-Windows host I find it somehow
overcomplicated now when we are trying to get it running at least on native
Linux x86*.
The 'compile' project needs a larger port effort to run on MS-Windows.
gdb/ChangeLog
2014-12-17 Jan Kratochvil <jan.kratochvil@redhat.com>
Fix MinGW compilation.
* compile/compile.c (get_compile_file_tempdir): Call error if
!HAVE_MKDTEMP.
* config.in: Regenerate.
* configure: Regenerate.
* configure.ac (AC_CHECK_FUNCS): Add mkdtemp.
gdb/testsuite/ChangeLog
2014-12-17 Jan Kratochvil <jan.kratochvil@redhat.com>
Fix MinGW compilation.
* gdb.compile/compile-ops.exp: Update untested message if
!skip_compile_feature_tests.
* gdb.compile/compile-setjmp.exp: Likewise.
* gdb.compile/compile-tls.exp: Likewise.
* gdb.compile/compile.exp: Likewise.
* lib/gdb.exp (skip_compile_feature_tests): Check also "Command not
supported on this host".
Anytime you can remove a symbol lookup that loops over all objfiles
is A Good Thing.
The call to lookup_static_symbol in valops.c:value_maybe_namespace_elt
is redundant with this call in cp_lookup_nested_symbol:
/* Now search all static file-level symbols. We have to do this
for things like typedefs in the class. We do not try to
guess any imported namespace as even the fully specified
namespace search is already not C++ compliant and more
assumptions could make it too magic. */
size = strlen (parent_name) + 2 + strlen (nested_name) + 1;
concatenated_name = alloca (size);
xsnprintf (concatenated_name, size, "%s::%s",
parent_name, nested_name);
sym = lookup_static_symbol (concatenated_name, VAR_DOMAIN);
if (sym != NULL)
return sym;
Earlier in value_maybe_namespace_elt we do this:
sym = cp_lookup_symbol_namespace (namespace_name, name,
get_selected_block (0), VAR_DOMAIN);
That sequence goes like:
value_maybe_namespace_elt
-> cp_lookup_symbol_namespace
-> cp_lookup_symbol_in_namespace
-> lookup_symbol_file
-> cp_lookup_nested_symbol
-> lookup_static_symbol
The call was added in commit 41f62f3939.
https://sourceware.org/ml/gdb-patches/2010-06/msg00663.html
With a part 2 here:
https://sourceware.org/ml/gdb-patches/2010-06/msg00664.html
At the time the call to lookup_static_symbol (spelled
lookup_static_symbol_aux at the time) was needed.
However, this patch, 8dea366bbe,
https://sourceware.org/ml/gdb-patches/2012-11/msg00387.html
augmented lookup_symbol_file to call cp_lookup_nested_symbol
and introduced the redundancy.
It's kinda buried, so it's totally not unexpected that this happened.
gdb/ChangeLog:
* valops.c (value_maybe_namespace_elt): Remove redundant call to
lookup_static_symbol.
gdb/ChangeLog:
* buildsym.c: Add comments describing how the buildsym machinery
is used by the various file formats.
(really_free_pendings): Enhance function comment.
See pending_macros to NULL. Simplify resetting pending_addrmap.
Call free_buildsym_compunit.
(free_buildsym_compunit): Set current_subfile to NULL.
(prepare_for_building): New function.
(start_symtab): Call it. Remove call to set_last_source_file.
(restart_symtab): New arg "cust". All callers updated.
Simplify, call prepare_for_building. Re-initialize buildsym_compunit.
(reset_symtab_globals): Enhance function comment.
Set local_symbols, file_symbols, global_symbols to NULL.
Set pending_macros to NULL. Simplify resetting pending_addrmap.
Call free_buildysym_compunit.
(end_symtab_without_blockvector): Delete. All callers updated.
(end_symtab_with_blockvector): Remove redundant call to
free_buildsym_compunit.
(augment_type_symtab): Remove arg "cust". All callers updated.
(buildsym_init): Remove resetting of free_pendings, file_symbols,
global_symbols, pending_blocks, pending_macros. Instead make
handling consistent with pending_addrmap: Assert value was reset
at end of previous symtab building. Initialize context_stack here.
This fixes a failure of the test case "complete 'info registers '" in
completion.exp on architectures where the user registers have numbers
above 99. In that case the output of "maint print user-registers" was
no longer indented, and the regexp in the test case failed to add them
to the list of expected completion results. The fix also swaps the
columns "Name" and "Nr", such that the indentation is always the same,
and to be consistent with the output of "maint print registers".
gdb/ChangeLog:
* user-regs.c (maintenance_print_user_registers): Swap "Nr" and
"Name" columns. Assure that the output is always indented.
gdb/testsuite/ChangeLog:
* gdb.base/completion.exp: Adjust to format changes of "maint
print user-registers".
This patch enhances GDB on GNU/Linux systems in the situation where
we are debugging an inferior that was created from GDB (as opposed
to attached to), by asking the kernel to kill the inferior if GDB
terminates without doing it itself.
This would typically happen when GDB encounters a problem and
crashes, or when it gets killed by an external process. This can
be observed by starting a program under GDB, and then killing
GDB with signal 9. After GDB is killed, the inferior still remains.
This patch also fixes GDBserver similarly.
This fix is conditional on the kernel supporting the PTRACE_O_EXITKILL
feature. On older kernels, the behavior remains unchanged.
gdb/ChangeLog:
* nat/linux-ptrace.h (PTRACE_O_EXITKILL): Define if not
already defined.
(linux_enable_event_reporting): Add parameter "attached".
* nat/linux-ptrace.c (linux_test_for_exitkill): New forward
declaration. New function.
(linux_check_ptrace_features): Add linux_test_for_exitkill call.
(linux_enable_event_reporting): Add new parameter "attached".
Do not call ptrace with the PTRACE_O_EXITKILL if ATTACHED is
nonzero.
* linux-nat.c (linux_init_ptrace): Add parameter "attached".
Use it. Update function description.
(linux_child_post_attach, linux_child_post_startup_inferior):
Update call to linux_enable_event_reporting.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_low_filter_event): Update call to
linux_enable_event_reporting following the addition of
a new parameter to that function.
Tested on x86_64-linux, native and native-gdbserver.
I also verified by hand that the inferior gets killed when killing
GDB in the "run" case, while the inferior remains in the "attach"
case. Same for GDBserver.
We define an enum ARG_MAX in linux_infcall_mmap, but it is conflict
with macro ARG_MAX which is defined in /usr/include/linux/limits.h.
This causes a build failure below,
gdb/linux-tdep.c: In function 'linux_infcall_mmap':
gdb/linux-tdep.c:1945:70: error: expected identifier before numeric constant
the enum in the pre-processed source becomes:
enum
{
ARG_ADDR, ARG_LENGTH, ARG_PROT, ARG_FLAGS, ARG_FD, ARG_OFFSET, 131072
};
This patch is to replace ARG_MAX with ARG_LAST.
gdb:
2014-12-16 Yao Qi <yao@codesourcery.com>
* linux-tdep.c (linux_infcall_mmap): Replace ARG_MAX with
ARG_LAST.
This patch introduces find_inferior_ptid to replace the common idiom
find_inferior_pid (ptid_get_pid (...));
It replaces all the instances of that idiom that I found with the new
function.
No significant changes before/after the patch in the regression suite
on amd64 linux.
gdb/ChangeLog:
* inferior.c (find_inferior_ptid): New function.
* inferior.h (find_inferior_ptid): New declaration.
* ada-tasks.c (ada_get_task_number): Use find_inferior_ptid.
* corelow.c (core_pid_to_str): Same.
* darwin-nat.c (darwin_resume): Same.
* infrun.c (fetch_inferior_event): Same.
(get_inferior_stop_soon): Same.
(handle_inferior_event): Same.
(handle_signal_stop): Same.
* linux-nat.c (resume_lwp): Same.
(stop_wait_callback): Same.
* mi/mi-interp.c (mi_new_thread): Same.
(mi_thread_exit): Same.
* proc-service.c (ps_pglobal_lookup): Same.
* record-btrace.c (record_btrace_step_thread): Same.
* remote-sim.c (gdbsim_close_inferior): Same.
(gdbsim_resume): Same.
(gdbsim_stop): Same.
* sol2-tdep.c (sol2_core_pid_to_str): Same.
* target.c (memory_xfer_partial_1): Same.
(default_thread_address_space): Same.
* thread.c (thread_change_ptid): Same.
(switch_to_thread): Same.
(do_restore_current_thread_cleanup): Same.
The type of the function pointer PyOS_ReadlineFunctionPointer (part of the
Python C API), which we use, slightly changed starting with Python 3.4. The
signature went from
PyAPI_DATA(char) *(*PyOS_ReadlineFunctionPointer)(FILE *, FILE *, char *);
to
PyAPI_DATA(char) *(*PyOS_ReadlineFunctionPointer)(FILE *, FILE *, const char *);
The parameter that changed is the prompt text.
This commits adjust gdb accordingly by making the prompt_arg parameter
const, as well as the fallouts of that. I needed to rework how
annotations are added to the prompt, since the it is now const. If
annotations are enabled, it will make a copy of the prompt overwrite the
prompt variable that is used throughout the function. Otherwise, no copy
is done and the original prompt_arg value is passed.
I changed the signature of deprecated_readline_hook. I would've changed any
user of it, but it seems like nothing is using it,
Built-tested with python 2.7.x, 3.3.y and 3.4.z.
gdb/ChangeLog:
* defs.h (gdb_readline): Constify argument.
(gdb_readline_wrapper): Same.
(command_line_input): Same.
(deprecated_readline_hook): Same.
* top.c (deprecated_readline_hook): Same.
(gdb_readline): Same.
(gdb_readline_wrapper): Same.
(command_line_input): Constify argument. Pass prompt to
called functions instead of local_prompt, overwriting prompt
if using annotations.
* event-top.h (display_gdb_prompt): Constify argument.
* event-top.c (display_gdb_prompt): Same.
* python/py-gdb-readline.c (gdbpy_readline_wrapper): Constify
argument if building with Python 3.4 and up.
Signed-off-by: Simon Marchi <simon.marchi@ericsson.com>
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().
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>
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.
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.
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 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.
Hi,
I see many fails in dw2-dir-file-name.exp on arm target when test
case is compiled with -marm, however, these fails are disappeared when
test case is compiled with -mthumb.
The difference of pass and fail shown below is that "0x000085d4 in" isn't
printed out, but test case expects to see it.
-Breakpoint 2, compdir_missing__ldir_missing__file_basename () at tmp-dw2-dir-file-name.c:999^M
-(gdb) FAIL: gdb.dwarf2/dw2-dir-file-name.exp: compdir_missing__ldir_missing__file_basename: continue to breakpoint: compdir_missing__ldir_missing__file_basename
+Breakpoint 2, 0x000085d4 in compdir_missing__ldir_missing__file_basename () at tmp-dw2-dir-file-name.c:999^M
+(gdb) PASS: gdb.dwarf2/dw2-dir-file-name.exp: compdir_missing__ldir_missing__file_basename: continue to breakpoint: compdir_missing__ldir_missing__file_basename
This difference is caused by setting breakpoint at the first instruction
in the function (actually, the first instruction in prologue, at [1]),
so that frame_show_address returns false, and print_frame doesn't print the
address.
0x00008620 <+0>: push {r11} ; (str r11, [sp, #-4]!) <--[1]
0x00008624 <+4>: add r11, sp, #0
0x00008628 <+8>: ldr r3, [pc, #24] ; 0x8648 <compdir_missing__ldir_missing__file_basename+40>
0x0000862c <+12>: ldr r3, [r3]
0x00008630 <+16>: add r3, r3, #1
0x00008634 <+20>: ldr r2, [pc, #12] ; 0x8648 <compdir_missing__ldir_missing__file_basename+40>
Then, it must be the arm_skip_prologue's fault that unable to skip
instructions in prologue. At the end of arm_skip_prologue, it matches
several instructions, such as "str r(0123),[r11,#-nn]" and
"str r(0123),[sp,#nn]", but "push {r11}" isn't handled.
These instruction matching code in arm_skip_prologue, which can be regarded
as leftover of development for many years, should be merged to
arm_analyze_prologue and use arm_analyze_prologue in arm_skip_prologue.
Here is the something like the history of arm_{skip,scan,analyze}_prologue.
Around 2002, there are arm_skip_prologue and arm_scan_prologue, but code are
duplicated to some extent. When match an instruction, both functions should
be modified, for example in Michael Snyder's patch
https://sourceware.org/ml/gdb-patches/2002-05/msg00205.html and Michael
expressed the willingness to merge both into one. Daniel added code call
thumb_analyze_prologue in arm_skip_prologue in 2006, but didn't handle its
counterpart arm_analyze_prologue, which is added in 2010
<https://sourceware.org/ml/gdb-patches/2010-03/msg00820.html>
however, the instructions matching at the bottom of arm_skip_prologue wasn't
cleaned up. This patch is to merge them into arm_analyze_prologue.
gdb:
2014-12-12 Yao Qi <yao@codesourcery.com>
PR tdep/14261
* arm-tdep.c (arm_skip_prologue): Remove unused local variable
'skip_pc'. Remove code skipping prologue instructions, use
arm_analyze_prologue instead.
(arm_analyze_prologue): Stop the scanning for unrecognized
instruction when skipping prologue.
Simon Marchi
Yao Qi
Doug Evans
Jan Kratochvil
Andreas Arnez
Joel Brobecker
Catalin Udma
Tom Tromey
Doug Evans
Maciej W. Rozycki
Andreas Arnez