'g' command returns hex-string as response so simply checking for 'E'
to determine if it failed is not enough and can trigger spurious error
messages. For example, invalid behaviour can be easily triggered on
Cortex-M as follows:
(gdb) set $r0 = 0xe0
Sending packet: $P0=e0000000#72...Packet received: OK
Packet P (set-register) is supported
Sending packet: $g#67...Packet received: E0000000849A0020...
Remote failure reply: E0000000849A0020...
This patch fixes the problem by calling putpkt()/getpkt() directly and
checking result with packet_check_result(). This works fine since Enn
response has odd number of bytes while proper response has even number
of bytes.
Also, remote_send() is now not used anywhere so it can be removed.
gdb/Changelog:
2018-04-26 Andrzej Kaczmarek <andrzej.kaczmarek@codecoup.pl>
PR remote/9665
* remote.c (send_g_packet): Use putpkt/getpkt/packet_check_result
instead of remote_send.
(remote_send): Remove.
I noticed that if you set a breakpoint on an ifunc before the ifunc is
resolved, and then let the program call the ifunc, thus resolving it,
GDB end up with a location for that original breakpoint that is
pointing to the ifunc target, but it is left pointing to the first
address of the function, instead of after its prologue. After
prologue is what you get if you create a new breakpoint at that point.
1) With no debug info for the target function:
1.a) Set before resolving, and then program continued passed resolving:
Num Type Disp Enb Address What
1 breakpoint keep y 0x0000000000400753 <final>
1.b) Breakpoint set after inferior resolved ifunc:
Num Type Disp Enb Address What
2 breakpoint keep y 0x0000000000400757 <final+4>
2) With debug info for the target function:
1.a) Set before resolving, and then program continued passed resolving:
Num Type Disp Enb Address What
1 breakpoint keep y 0x0000000000400753 in final at gdb/testsuite/gdb.base/gnu-ifunc-final.c:20
1.b) Breakpoint set after inferior resolved ifunc:
Num Type Disp Enb Address What
2 breakpoint keep y 0x000000000040075a in final at gdb/testsuite/gdb.base/gnu-ifunc-final.c:21
The problem is that elf_gnu_ifunc_resolver_return_stop (called by the
internal breakpoint that traps the resolver returning) does not agree
with linespec.c:minsym_found. It does not skip to the function's
start line (i.e., past the prologue). We can now use the
find_function_start_sal overload added by the previous commmit to fix
this.
New tests included, which fail before the patch, and pass afterwards.
gdb/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* elfread.c (elf_gnu_ifunc_resolver_return_stop): Use
find_function_start_sal instead of find_pc_line.
gdb/testsuite/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* gdb.base/gnu-ifunc.exp (set-break): Test that GDB resolves
ifunc breakpoint locations correctly of ifunc breakpoints set
while the program resolves the ifunc.
This patch extends/rewrites the gdb.base/gnu-ifunc.exp testcase to
cover the many different fixes in earlier patches. (This was actually
what encovered most of the problems.)
The current testcase uses an ifunc symbol with the same name as the
ifunc resolver symbol and makes sure to compile the ifunc resolver
without debug info. That does not model how ifuncs are implemented in
gcc/ifunc nowadays. Instead, what we have is that the glibc ifunc
resolvers nowadays are written in C and end up with debug info.
Also, in some cases the ifunc target is written in assembly, but in
other cases it's written in C. In the case of target function written
in C, if the target function has debug info, when we set a break on
the ifunc, we want to set it past the prologue of the target function.
Currently GDB gets that wrong.
To make sure we cover all the different scenarios, the testcase is
tweaked to cover all the different combinations of
- An ifunc resolver with the same name as the user-visible symbol vs
an ifunc resolver with a different name as the user-visible symbol.
- ifunc resolver compiled with and without debug info.
- ifunc target function compiled with and without debug info.
The testcase currently sets breakpoints on ifuncs, calls ifunc
functions, steps into ifunc functions, etc. After this series, this
all works and the testcase passes cleanly.
While working on this, I noticed that "b gnu_ifunc" before and after
the inferior resolved the ifunc would end up with a breakpoint with
different locations. That's now covered by new tests inside the new
"set-break" procedure.
It also tests other things like making sure we can't call an ifunc
without a return-type case if we don't know the type of the target.
And making sure that we pass enough arguments when we do know the
type.
gdb/testsuite/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* gdb.base/gnu-ifunc-final.c: New file.
* gdb.base/gnu-ifunc.c (final): Delete, moved to gnu-ifunc-final.c.
* gdb.base/gnu-ifunc.exp (executable): Delete.
(staticexecutable): Adjust.
(lib_opts, exec_opts): Delete.
(make_binsuffix, build, set-break): New procedures.
(misc_tests): New, with tests factored out from the top level.
(top level): Test different combinations of ifunc resolver name,
resolver with and with debug info, and ifunc target with and
without debug info. Wrap static tests with with_target_prefix.
Running the new tests added later in the series on PPC64 (ELFv1)
revealed that the current ifunc support needs a bit of a design rework
to work properly on PPC64/ELFv1, as most of the new tests fail. The
ifunc support only kind of works today if the ifunc symbol and the
resolver have the same name, as is currently tested by the
gdb.base/gnu-ifunc.exp testcase, which is unlike how ifuncs are
written nowadays.
The crux of the problem is that ifunc symbols are really function
descriptors, not text symbols:
44: 0000000000020060 104 FUNC GLOBAL DEFAULT 18 gnu_ifunc_resolver
54: 0000000000020060 104 GNU_IFUNC GLOBAL DEFAULT 18 gnu_ifunc
But, currently GDB only knows about ifunc symbols that are text
symbols. GDB's support happens to work in practice for PPC64 when the
ifunc and resolver are one and only, like in the current
gdb.base/gnu-ifunc.exp testcase:
15: 0000000000020060 104 GNU_IFUNC GLOBAL DEFAULT 18 gnu_ifunc
because in that case, the synthetic ".gnu_ifunc" entry point text
symbol that bfd creates from the actual GNU ifunc "gnu_ifunc" function
(descriptor) symbol ends up with the the "is a gnu ifunc" flag set /
copied over:
(gdb) maint print msymbols
...
[ 8] i 0x9c4 .gnu_ifunc section .text <<< mst_text_gnu_ifunc
...
[29] D 0x20060 gnu_ifunc section .opd crtstuff.c <<< mst_data
But, if the resolver gets a distinct symbol/name from the ifunc
symbol, then we end up with this:
(gdb) maint print msymbols
[ 8] T 0x9e4 .gnu_ifunc_resolver section .text <<< mst_text
...
[29] D 0x20060 gnu_ifunc section .opd crtstuff.c <<< mst_data
[30] D 0x20060 gnu_ifunc_resolver section .opd crtstuff.c <<< mst_data
I have a follow up bfd patch that turns that into:
(gdb) maint print msymbols
+ [ 8] i 0x9e4 .gnu_ifunc section .text <<< mst_text_gnu_ifunc
[ 8] T 0x9e4 .gnu_ifunc_resolver section .text <<< mst_text
...
[29] D 0x20060 gnu_ifunc section .opd crtstuff.c
[30] D 0x20060 gnu_ifunc_resolver section .opd crtstuff.c
but that won't help everything. We still need this patch.
Specifically, when we do a symbol lookup by name, like e.g., to call a
function (see c-exp.y hunk), e.g., "p gnu_ifunc()", then we need to
know that the found "gnu_ifunc" minimal symbol is an ifunc in order to
do some special processing. But, on PPC, that lookup by name finds
the function descriptor symbol, which presently is just a mst_data
symbol, while at present, we look for mst_text_gnu_ifunc symbols to
decide whether to do special GNU ifunc processing. In most of those
places, we could try to resolve the function descriptor with
gdbarch_convert_from_func_ptr_addr, and then lookup the minimal symbol
at the resolved PC, see if that finds a minimal symbol of type
mst_text_gnu_ifunc. If so, then we could assume that the original
mst_dadta / function descriptor "gnu_ifunc" symbol was an ifunc. I
tried it, and it mostly works, even if it's not the most efficient.
However, there's one case that can't work with such a design -- it's
that of the user calling the ifunc resolver directly to debug it, like
"p gnu_ifunc_resolver(0)", expecting that to return the function
pointer of the final function (which is exercised by the new tests
added later). In this case, with the not-fully-working solution, we'd
resolve the function descriptor, find that there's an
mst_text_gnu_ifunc symbol for the resolved address, and proceed
calling the function as if we tried to call "gnu_ifunc", the
user-visible GNU ifunc symbol, instead of the resolver. I.e., it'd be
impossible to call the resolver directly as a normal function.
Introducing mst_data_gnu_ifunc eliminates the need for several
gdbarch_convert_from_func_ptr_addr calls, and, fixes the "call
resolver directly" use case mentioned above too. It's the cleanest
approach I could think of.
In sum, we make GNU ifunc function descriptor symbols get a new
"mst_data_gnu_ifunc" minimal symbol type instead of the bare mst_data
type. So when symbol lookup by name finds such a minimal symbol, we
know we found an ifunc symbol, without resolving the entry/text
symbol. If the user calls the the resolver symbol instead, like "p
gnu_ifunc_resolver(0)", then we'll find the regular mst_data symbol
for "gnu_ifunc_resolver", and we'll call the resolver function as just
another regular function.
With this, most of the GNU ifunc tests added by a later patch pass on
PPC64 too. The following bfd patch fixes the remaining issues.
gdb/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* breakpoint.c (set_breakpoint_location_function): Handle
mst_data_gnu_ifunc.
* c-exp.y (variable production): Handle mst_data_gnu_ifunc.
* elfread.c (elf_symtab_read): Give data symbols with
BSF_GNU_INDIRECT_FUNCTION set mst_data_gnu_ifunc type.
(elf_rel_plt_read): Update comment.
* linespec.c (convert_linespec_to_sals): Handle
mst_data_gnu_ifunc.
(minsym_found): Handle mst_data_gnu_ifunc.
* minsyms.c (msymbol_is_function, minimal_symbol_reader::record)
(find_solib_trampoline_target): Handle mst_data_gnu_ifunc.
* parse.c (find_minsym_type_and_address): Handle
mst_data_gnu_ifunc.
* symmisc.c (dump_msymbols): Handle mst_data_gnu_ifunc.
* symtab.c (find_gnu_ifunc): Handle mst_data_gnu_ifunc.
* symtab.h (minimal_symbol_type) <mst_text_gnu_ifunc>: Update
comment.
<mst_data_gnu_ifunc>: New enumerator.
When we're stepping (with "step"), we want to skip trampoline-like
functions automatically, including GNU ifunc resolvers. That is done
by infrun.c calling into:
in_solib_dynsym_resolve_code
-> svr4_in_dynsym_resolve_code
-> in_gnu_ifunc_stub
A problem here is that if there's a regular text symbol at the same
address as the ifunc symbol, the minimal symbol lookup in
in_gnu_ifunc_stub may miss the GNU ifunc symbol:
(...)
41: 000000000000071a 53 FUNC GLOBAL DEFAULT 11 gnu_ifunc_resolver
(...)
50: 000000000000071a 53 IFUNC GLOBAL DEFAULT 11 gnu_ifunc
(...)
This causes this FAIL in the tests added later in the series:
(gdb) PASS: gdb.base/gnu-ifunc.exp: resolver_attr=1: resolver_debug=0: final_debug=0: resolver received HWCAP
set step-mode on
(gdb) PASS: gdb.base/gnu-ifunc.exp: resolver_attr=1: resolver_debug=0: final_debug=0: set step-mode on
step
0x00007ffff7bd371a in gnu_ifunc_resolver () from build/gdb/testsuite/outputs/gdb.base/gnu-ifunc/gnu-ifunc-lib-1-0-0.so
(gdb) FAIL: gdb.base/gnu-ifunc.exp: resolver_attr=1: resolver_debug=0: final_debug=0: step
Above, GDB simply thought that it stepped into a regular function, so
it stopped stepping, while it should have continued stepping past the
resolver.
The fix is to teach minimal symbol lookup to prefer GNU ifunc symbols
if desired.
gdb/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* minsyms.c (lookup_minimal_symbol_by_pc_section_1): Rename to ...
(lookup_minimal_symbol_by_pc_section): ... this. Replace
'want_trampoline' parameter by a lookup_msym_prefer parameter.
Handle it.
(lookup_minimal_symbol_by_pc_section): Delete old implementation.
(lookup_minimal_symbol_by_pc): Adjust.
(in_gnu_ifunc_stub): Prefer GNU ifunc symbols.
(lookup_solib_trampoline_symbol_by_pc): Adjust.
* minsyms.h (lookup_msym_prefer): New enum.
(lookup_minimal_symbol_by_pc_section): Replace 'want_trampoline'
parameter by a lookup_msym_prefer parameter.
elf_gnu_ifunc_record_cache doesn't ever record anything on PPC64
(tested on gcc110 on the compile farm, CentOS 7.4, ELFv1), because
that expects to find PLT symbols in the .plt section, while there we
get:
(gdb) info symbol 'gnu_ifunc@plt'
gnu_ifunc@plt in section .text
^^^^^
I guess that may be related to the comment in ppc-linux-tdep.c that
says "For secure PLT, stub is in .text".
In any case, this commit fixes the issue by making the function look
at the symbol name instead of at the section.
gdb/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* elfread.c (elf_gnu_ifunc_record_cache): Check if the symbol name
ends in "@plt" instead of looking at the symbol's section.
I need to make the ifunc resolving code in elfread.c skip the target
function's prologue like minsym_found does. I thought of factoring
that out to a separate function, but turns out there's already a
comment in find_function_start_sal that says that should agree with
minsym_found...
Instead of making sure the code agrees with a comment, factor out the
common code to a separate function and use it from both places.
Note that the current find_function_start_sal does a bit more than
minsym_found's equivalent (the "We always should ..." bit), though
that's probably a latent bug.
gdb/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* linespec.c (minsym_found): Use find_function_start_sal CORE_ADDR
overload.
* symtab.c (find_function_start_sal(CORE_ADDR, obj_section *,bool)):
New, factored out from ...
(find_function_start_sal(symbol *, int)): ... this. Reimplement
and use bool.
* symtab.h (find_function_start_sal(CORE_ADDR, obj_section *,bool)):
New.
(find_function_start_sal(symbol *, int)): Change boolean parameter
type to bool.
Not used anywhere any longer.
If this is ever reinstated, note that this case:
cache_pc_function_is_gnu_ifunc = TYPE_GNU_IFUNC (SYMBOL_TYPE (f));
was incorrect in that regular symbols never have type marked as GNU
ifunc type, only minimal symbols. At some point I had some fix that
checking the matching minsym here. But in the end I ended up just
eliminating need for this function, so that fix was not necessary.
gdb/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* blockframe.c (cache_pc_function_is_gnu_ifunc): Delete. Remove
all references.
(find_pc_partial_function_gnu_ifunc): Rename to ...
(find_pc_partial_function): ... this, and remove references to
'is_gnu_ifunc_p'.
(find_pc_partial_function): Delete old implementation.
* symtab.h (find_pc_partial_function_gnu_ifunc): Delete.
Without this patch, some of the tests added to gdb.base/gnu-ifunc.exp
by a following patch fail like so:
FAIL: gdb.base/gnu-ifunc.exp: resolver_attr=0: resolver_debug=1: resolved_debug=0: set-break: before resolving: break gnu_ifunc
FAIL: gdb.base/gnu-ifunc.exp: resolver_attr=0: resolver_debug=1: resolved_debug=0: set-break: before resolving: info breakpoints
FAIL: gdb.base/gnu-ifunc.exp: resolver_attr=0: resolver_debug=1: resolved_debug=0: set-break: after resolving: break gnu_ifunc
FAIL: gdb.base/gnu-ifunc.exp: resolver_attr=0: resolver_debug=1: resolved_debug=0: set-break: after resolving: info breakpoints
FAIL: gdb.base/gnu-ifunc.exp: resolver_attr=0: resolver_debug=1: resolved_debug=1: set-break: before resolving: break gnu_ifunc
FAIL: gdb.base/gnu-ifunc.exp: resolver_attr=0: resolver_debug=1: resolved_debug=1: set-break: before resolving: info breakpoints
FAIL: gdb.base/gnu-ifunc.exp: resolver_attr=0: resolver_debug=1: resolved_debug=1: set-break: after resolving: break gnu_ifunc
FAIL: gdb.base/gnu-ifunc.exp: resolver_attr=0: resolver_debug=1: resolved_debug=1: set-break: after resolving: info breakpoints
All of them trigger iff:
- you have debug info for the ifunc resolver.
- the resolver and the user-visible symbol have the same name.
If you have an ifunc that has a resolver with the same name as the
user visible symbol, debug info for the resolver masks out the ifunc
minsym. When you set a breakpoint by name on the user visible symbol,
GDB finds the DWARF symbol for the resolver, and thinking that it's a
regular function, sets a breakpoint location past its prologue.
Like so, location 1.2, before the ifunc is resolved by the inferior:
(gdb) break gnu_ifunc
Breakpoint 2 at 0x7ffff7bd36ea (2 locations)
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y <MULTIPLE>
1.1 y 0x00007ffff7bd36ea <gnu_ifunc>
1.2 y 0x00007ffff7bd36f2 in gnu_ifunc at src/gdb/testsuite/gdb.base/gnu-ifunc-lib.c:34
(gdb)
And like so, location 2.2, if you set the breakpoint after the ifunc
is resolved by the inferior (to "final"):
(gdb) break gnu_ifunc
Breakpoint 5 at 0x400757 (2 locations)
(gdb) info breakpoints
Num Type Disp Enb Address What
2 breakpoint keep y <MULTIPLE>
2.1 y 0x000000000040075a in final at src/gdb/testsuite/gdb.base/gnu-ifunc-resd.c:21
2.2 y 0x00007ffff7bd36f2 in gnu_ifunc at src/gdb/testsuite/gdb.base/gnu-ifunc-lib.c:34
(gdb)
I don't think this is right because when users set a breakpoint at an
ifunc, they don't care about debugging the resolver. Instead what you
should is a single location for the ifunc in the first case, and a
single location of the ifunc target in the second case.
gdb/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* linespec.c (struct bound_minimal_symbol_search_key): New.
(convert_linespec_to_sals): Sort minimal symbols earlier. Don't
skip first line if we found a GNU ifunc minimal symbol by name.
(compare_msymbols): Change parameters to work with a destructured
lhs minsym.
(compare_msymbols_for_qsort, compare_msymbols_for_bsearch): New
functions.
This fixes setting breakpoints on ifunc functions by name after the
ifunc has already been resolved.
In that case, if you have debug info for the ifunc resolver, without
the fix, then gdb puts a breakpoint past the prologue of the resolver,
instead of setting a breakpoint at the ifunc target:
break gnu_ifunc
Breakpoint 4 at 0x7ffff7bd36f2: file src/gdb/testsuite/gdb.base/gnu-ifunc-lib.c, line 34.
(gdb) continue
Continuing.
[Inferior 1 (process 13300) exited normally]
(gdb)
above we should have stopped at "final", but didn't because we never
resolved the ifunc to the final location.
If you don't have debug info for the resolver, GDB manages to resolve
the ifunc target, but, it should be setting a breakpoint after the
prologue of the final function, and instead what you get is that GDB
sets a breakpoint on the first address of the target function. With
the gnu-ifunc.exp tests added by a later patch, we get, without the
fix:
(gdb) break gnu_ifunc
Breakpoint 4 at 0x400753
(gdb) continue
Continuing.
Breakpoint 4, final (arg=1) at src/gdb/testsuite/gdb.base/gnu-ifunc-final.c:20
20 {
vs, fixed:
(gdb) break gnu_ifunc
Breakpoint 4 at 0x40075a: file src/gdb/testsuite/gdb.base/gnu-ifunc-final.c, line 21.
(gdb) continue
Continuing.
Breakpoint 4, final (arg=2) at src/gdb/testsuite/gdb.base/gnu-ifunc-final.c:21
21 return arg + 1;
(gdb)
Fix the problems above by moving the ifunc target resolving to
linespec.c, before we skip a function's prologue. We need to save
something in the sal, so that set_breakpoint_location_function knows
that it needs to create a bp_gnu_ifunc_resolver bp_location. Might as
well just save a pointer to the minsym.
gdb/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* breakpoint.c (set_breakpoint_location_function): Don't resolve
ifunc targets here. Instead, if we have an ifunc minsym, use its
address/name.
(add_location_to_breakpoint): Store the minsym and the objfile in
the breakpoint location.
* breakpoint.h (bp_location) <msymbol, objfile>: New fields.
* linespec.c (minsym_found): Resolve GNU ifunc targets here.
Record the minsym in the sal.
* symtab.h (symtab_and_line) <msymbol>: New field.
The next patch will add a call to elf_gnu_ifunc_resolve_by_got that
trips on a latent buglet -- the function is writing to its output
parameter even if the address wasn't found, confusing the caller. The
function's intro comment says:
/* Try to find the target resolved function entry address of a STT_GNU_IFUNC
function NAME. If the address is found it is stored to *ADDR_P (if ADDR_P
is not NULL) and the function returns 1. It returns 0 otherwise.
So fix the function accordingly.
gdb/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* elfread.c (elf_gnu_ifunc_resolve_by_got): Don't write to *ADDR_P
unless we actually resolved the ifunc.
If the GNU ifunc resolver has the same name as the user visible
symbol, and the resolver has debug info, then the DWARF info for the
resolver masks the ifunc minsym. In that scenario, if you try calling
the ifunc from GDB, you call the resolver instead. With the
gnu-ifunc.exp testcase added in a following patch, you'd see:
(gdb) p gnu_ifunc (3)
$1 = (int (*)(int)) 0x400753 <final>
(gdb) FAIL: gdb.base/gnu-ifunc.exp: resolver_attr=0: resolver_debug=1: resolved_debug=0: p gnu_ifunc (3)
^^^^^^^^^^^^^^^^
That is, we called the ifunc resolver manually, which returned a
pointer to the ifunc target function ("final"). The "final" symbol is
the function that GDB should have called automatically,
~~~~~~~~~~~~
int
final (int arg)
{
return arg + 1;
}
~~~~~~~~~
which is what happens if you don't have debug info for the resolver:
(gdb) p gnu_ifunc (3)
$1 = 4
(gdb) PASS: gdb.base/gnu-ifunc.exp: resolver_attr=0: resolver_debug=0: resolved_debug=1: p gnu_ifunc (3)
^^^^^^^^^^^^^^^^
or if the resolver's symbol has a different name from the ifunc (as is
the case with modern uses of ifunc via __attribute__ ifunc, such as
glibc uses):
(gdb) p gnu_ifunc (3)
$1 = 4
(gdb) PASS: gdb.base/gnu-ifunc.exp: resolver_attr=1: resolver_debug=1: resolved_debug=0: p gnu_ifunc (3)
^^^^^^^^^^^^^^^
in which case after this patch, you can still call the resolver
directly if you want:
(gdb) p gnu_ifunc_resolver (3)
$1 = (int (*)(int)) 0x400753 <final>
gdb/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* c-exp.y (variable production): Prefer ifunc minsyms over
regular function symbols.
* symtab.c (find_gnu_ifunc): New function.
* minsyms.h (lookup_msym_prefer): New enum.
(lookup_minimal_symbol_by_pc_section): Replace 'want_trampoline'
parameter by a lookup_msym_prefer parameter.
* symtab.h (find_gnu_ifunc): New declaration.
After the previous patch, on Fedora 27 (glibc 2.26), if you try
calling strlen in the inferior, you now get:
(top-gdb) p strlen ("hello")
'__strlen_avx2' has unknown return type; cast the call to its declared return type
This is correct, because __strlen_avx2 is written in assembly.
We can improve on this though -- if the final ifunc resolved/target
function has no debug info, but the ifunc _resolver_ does have debug
info, we can try extracting the final function's type from the type
that the resolver returns. E.g.,:
typedef size_t (*strlen_t) (const char*);
size_t my_strlen (const char *) { /* some implementation */ }
strlen_t strlen_resolver (unsigned long hwcap) { return my_strlen; }
extern size_t strlen (const char *s);
__typeof (strlen) strlen __attribute__ ((ifunc ("strlen_resolver")));
In the strlen example above, the resolver returns strlen_t, which is a
typedef for pointer to a function that returns size_t. "strlen_t" is
the type of both the user-visible "strlen", and of the the target
function that implements it.
This patch teaches GDB to extract that type.
This is done for actual inferior function calls (in infcall.c), and
for ptype (in eval_call). By the time we get to either of these
places, we've already lost the original symbol/minsym, and only have
values and types to work with. Hence the changes to c-exp.y and
evaluate_var_msym_value, to ensure that we propagate the ifunc
minsymbol's info.
The change to make ifunc symbols have no/unknown return type exposes a
latent problem -- gdb.compile/compile-ifunc.exp calls a no-debug-info
function, but we did not warn about it. The test is fixed by this
commit too.
gdb/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* blockframe.c (find_gnu_ifunc_target_type): New function.
(find_function_type): New.
* eval.c (evaluate_var_msym_value): For GNU ifunc types, always
return a value with a memory address.
(eval_call): For calls to GNU ifunc functions, try to find the
type of the target function from the type that the resolver
returns.
* gdbtypes.c (objfile_type): Don't install a return type for ifunc
symbols.
* infcall.c (find_function_return_type): Delete.
(find_function_addr): Add 'function_type' parameter. For calls to
GNU ifunc functions, try to find the type of the target function
from the type that the resolver returns, and return it via
FUNCTION_TYPE.
(call_function_by_hand_dummy): Adjust to use the function type
returned by find_function_addr.
(find_function_addr): Add 'function_type' parameter and move
description here.
* symtab.h (find_function_type, find_gnu_ifunc_target_type): New
declarations.
gdb/testsuite/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* gdb.compile/compile-ifunc.exp: Also expect "function has unknown
return type" warnings.
Currently, on Fedora 27 (glibc 2.26), if you try to call strlen in the
inferior you get:
(gdb) p strlen ("hello")
$1 = (size_t (*)(const char *)) 0x7ffff554aac0 <__strlen_avx2>
strlen is an ifunc function, and what we see above is the result of
calling the ifunc resolver in the inferior. That returns a pointer to
the actual target function that implements strlen on my machine. GDB
should have turned around and called the resolver automatically
without the user noticing.
This is was caused by commit:
commit bf223d3e80
Date: Mon Aug 21 11:34:32 2017 +0100
Handle function aliases better (PR gdb/19487, errno printing)
which added the find_function_alias_target call to c-exp.y, to try to
find an alias with debug info for a minsym. For ifunc symbols, that
finds the ifunc's resolver if it has debug info (in the example it's
called "strlen_ifunc"), with the result that GDB calls that as a
regular function.
After this commit, we get now get:
(top-gdb) p strlen ("hello")
'__strlen_avx2' has unknown return type; cast the call to its declared return type
Which is correct, because __strlen_avx2 is written in assembly.
That'll be improved in a following patch, though.
gdb/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* c-exp.y (variable production): Skip finding an alias for ifunc
symbols.
Setting a breakpoint on an ifunc symbol after the ifunc has already
been resolved by the inferior should result in creating a breakpoint
location at the ifunc target. However, that's not what happens on
current Fedora:
(gdb) n
53 i = gnu_ifunc (1); /* break-at-call */
(gdb)
54 assert (i == 2);
(gdb) b gnu_ifunc
Breakpoint 2 at gnu-indirect-function resolver at 0x7ffff7bd36ee
(gdb) info breakpoints
Num Type Disp Enb Address What
2 STT_GNU_IFUNC resolver keep y 0x00007ffff7bd36ee <gnu_ifunc+4>
The problem is that elf_gnu_ifunc_resolve_by_got never manages to
resolve an ifunc target. The reason is that GDB never actually
creates the internal got.plt symbols:
(gdb) p 'gnu_ifunc@got.plt'
No symbol "gnu_ifunc@got.plt" in current context.
and this is because GDB expects that rela.plt has relocations for
.plt, while it actually has relocations for .got.plt:
Relocation section [10] '.rela.plt' for section [22] '.got.plt' at offset 0x570 contains 2 entries:
Offset Type Value Addend Name
0x0000000000601018 X86_64_JUMP_SLOT 000000000000000000 +0 __assert_fail
0x0000000000601020 X86_64_JUMP_SLOT 000000000000000000 +0 gnu_ifunc
Using an older system on the GCC compile farm (machine gcc15, an
x86-64 running Debian 6.0.8, with GNU ld 2.20.1), we see that it used
to be that we'd get a .rela.plt section for .plt:
Relocation section [ 9] '.rela.plt' for section [11] '.plt' at offset 0x578 contains 3 entries:
Offset Type Value Addend Name
0x0000000000600cc0 X86_64_JUMP_SLOT 000000000000000000 +0 __assert_fail
0x0000000000600cc8 X86_64_JUMP_SLOT 000000000000000000 +0 __libc_start_main
0x0000000000600cd0 X86_64_JUMP_SLOT 000000000000000000 +0 gnu_ifunc
Those offsets did point into .got.plt, as seen with objdump -h:
20 .got.plt 00000030 0000000000600ca8 0000000000600ca8 00000ca8 2**3
CONTENTS, ALLOC, LOAD, DATA
I also tested on gcc110 on the compile farm (PPC64 running CentOS
7.4.1708, with GNU ld 2.25.1), and there we see instead:
Relocation section [ 9] '.rela.plt' for section [23] '.plt' at offset 0x5d0 contains 4 entries:
Offset Type Value Addend Name
0x0000000010020148 PPC64_JMP_SLOT 000000000000000000 +0 __libc_start_main
0x0000000010020160 PPC64_JMP_SLOT 000000000000000000 +0 __gmon_start__
0x0000000010020178 PPC64_JMP_SLOT 000000000000000000 +0 __assert_fail
0x0000000010020190 PPC64_JMP_SLOT 000000000000000000 +0 gnu_ifunc
But note that those offsets point into .plt, not .got.plt, as seen
with objdump -h:
22 .plt 00000078 0000000010020130 0000000010020130 00010130 2**3
ALLOC
This commit makes us support all the different combinations above.
With that addressed, we now get:
(gdb) p 'gnu_ifunc@got.plt'
$1 = (<text from jump slot in .got.plt, no debug info>) 0x400753 <final>
And setting a breakpoint on the ifunc finds the ifunc target:
(gdb) b gnu_ifunc
Breakpoint 2 at 0x400753
(gdb) info breakpoints
Num Type Disp Enb Address What
2 breakpoint keep y 0x0000000000400753 <final>
gdb/ChangeLog:
2018-04-26 Pedro Alves <palves@redhat.com>
* elfread.c (elf_rel_plt_read): Look for relocations for .got.plt too.
Since f67c0c9171 ("Enable 'set print inferior-events' and improve
detach/fork/kill/exit messages"), when detaching a remote process, we
get, for detach against a remote target:
(gdb) detach
Detaching from program: ...., process 5388
Ending remote debugging.
[Inferior 1 (Thread 5388.5388) detached]
^^^^^^^^^^^^^^^^
That is incorrect, for it is printing a thread id as string while we
should be printing the process id instead. I.e., either one of:
[Inferior 1 (process 5388) detached]
[Inferior 1 (Remote target) detached]
depending on remote stub support for the multi-process extensions.
Similarly, after killing a process, we're printing thread ids while we
should be printing process ids. E.g., on native GNU/Linux:
(gdb) k
Kill the program being debugged? (y or n) y
[Inferior 1 (Thread 0x7ffff7faa8c0 (LWP 30721)) has been killed]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
while it should have been:
Kill the program being debugged? (y or n) y
[Inferior 1 (process 30721) has been killed]
^^^^^^^^^^^^^
There's a wording inconsistency between detach and kill:
[Inferior 1 (process 30721) has been killed]
[Inferior 1 (process 30721) detached]
Given we were already saying "detached" instead of "has been
detached", and we used to say just "exited", and given that the "has
been" doesn't really add any information, this commit changes the
message to just "killed":
[Inferior 1 (process 30721) killed]
gdb/ChangeLog:
2018-04-25 Pedro Alves <palves@redhat.com>
* infcmd.c (kill_command): Print the pid as string, not the whole
thread's ptid. Add comment. s/has been killed/killed/ in output
message.
* remote.c (remote_detach_1): Print the pid as string, not the
whole thread's ptid.
gdb/testsuite/ChangeLog:
2018-04-25 Pedro Alves <palves@redhat.com>
* gdb.base/hook-stop.exp: Expect "killed" instead of "has been
killed".
* gdb.base/kill-after-signal.exp: Likewise.
* gdb.threads/kill.exp: Likewise.
This patch aims to turn 'set print inferior-events' always on, and do
some cleanup on the messages printed by GDB when various inferior
events happen (attach, detach, fork, kill, exit).
To make sure that the patch is correct, I've tested it with a handful
of combinations of 'set follow-fork-mode', 'set detach-on-fork' and
'set print inferior-events'. In the end, I decided to make my
hand-made test into an official testcase. More on that below.
Using the following program as an example:
#include <unistd.h>
int main ()
{
fork ();
return 0;
}
We see the following outputs from the patched GDB:
- With 'set print inferior-events on':
(gdb) r
Starting program: a.out
[Detaching after fork from child process 27749]
[Inferior 1 (process 27745) exited normally]
(gdb)
- With 'set print inferior-events off':
(gdb) r
Starting program: a.out
[Inferior 1 (process 27823) exited normally]
(gdb)
Comparing this against an unpatched GDB:
- With 'set print inferior-events off' and 'set follow-fork-mode
child':
(gdb) r
Starting program: a.out
[Inferior 2 (process 5993) exited normally]
(gdb)
Compare this against an unpatched GDB:
(unpatched-gdb) r
Starting program: a.out
[New process 5702]
[Inferior 2 (process 5702) exited normally]
(unpatched-gdb)
It is possible to notice that, in this scenario, the patched GDB
will lose the '[New process %d]' message.
- With 'set print inferior-events on', 'set follow-fork-mode child'
and 'set detach-on-fork on':
(gdb) r
Starting program: a.out
[Attaching after process 27905 fork to child process 27909]
[New inferior 2 (process 27909)]
[Detaching after fork from parent process 27905]
[Inferior 1 (process 27905) detached]
[Inferior 2 (process 27909) exited normally]
(gdb)
Compare this output with an unpatched GDB, using the same settings:
(unpatched-gdb) r
Starting program: a.out
[New inferior 28033]
[Inferior 28029 detached]
[New process 28033]
[Inferior 2 (process 28033) exited normally]
[Inferior 28033 exited]
(unpatched-gdb)
As can be seen above, I've also made a few modifications to messages
that are printed when 'set print inferior-events' is on. For example,
a few of the messages did not contain the '[' and ']' as
prefix/suffix, which led to a few inconsistencies like:
Attaching after process 22995 fork to child process 22999.
[New inferior 22999]
Detaching after fork from child process 22999.
[Inferior 22995 detached]
[Inferior 2 (process 22999) exited normally]
So I took the opportunity and included the square brackets where
applicable. I have also made the existing messages more uniform, by
always printing "Inferior %d (process %d)..." where applicable. This
makes it easier to identify the inferior number and the PID number
from the messages.
As suggested by Pedro, the "[Inferior %d exited]" message from
'exit_inferior' has been removed, because it got duplicated when
'inferior-events' is on. I'm also using the
'add_{thread,inferior}_silent' versions (instead of their verbose
counterparts) on some locations, also to avoid duplicated messages.
For example, a patched GDB with 'set print inferior-events on', 'set
detach-on-fork on' and 'set follow-fork-mode child', but using
'add_thread', would print:
(gdb) run
Starting program: a.out
[Attaching after process 25088 fork to child process 25092.]
[New inferior 25092] <--- duplicated
[Detaching after fork from child process 25092.]
[Inferior 25088 detached]
[New process 25092] <--- duplicated
[Inferior 2 (process 25092) exited normally]
But if we use 'add_thread_silent' (with the same configuration as
before):
(gdb) run
Starting program: a.out
[Attaching after process 31606 fork to child process 31610]
[New inferior 2 (process 31610)]
[Detaching after fork from parent process 31606]
[Inferior 1 (process 31606) detached]
[Inferior 2 (process 31610) exited normally]
As for the tests, the configuration options being exercised are:
- follow-fork-mode: child/parent
- detach-on-fork: on/off
- print inferior-events: on/off
It was also necessary to perform adjustments on several testcases,
because the expected messages changed considerably.
Built and regtested on BuildBot, without regressions.
gdb/ChangeLog:
2018-04-24 Jan Kratochvil <jan.kratochvil@redhat.com>
Sergio Durigan Junior <sergiodj@redhat.com>
Pedro Alves <palves@redhat.com>
* infcmd.c (kill_command): Print message when inferior has
been killed.
* inferior.c (print_inferior_events): Remove 'static'. Set as
'1'.
(add_inferior): Improve message printed when
'print_inferior_events' is on.
(exit_inferior): Remove message printed when
'print_inferior_events' is on.
(detach_inferior): Improve message printed when
'print_inferior_events' is on.
(initialize_inferiors): Use 'add_inferior_silent' to set
'current_inferior_'.
* inferior.h (print_inferior_events): Declare here as
'extern'.
* infrun.c (follow_fork_inferior): Print '[Attaching...]' or
'[Detaching...]' messages when 'print_inferior_events' is on.
Use 'add_thread_silent' instead of 'add_thread'. Add '[' and ']'
as prefix/suffix for messages. Remove periods. Fix erroneous
'Detaching after fork from child...', replace it by '... from
parent...'.
(handle_vfork_child_exec_or_exit): Add '[' and ']' as
prefix/suffix when printing 'Detaching...' messages. Print
them when 'print_inferior_events' is on.
* remote.c (remote_detach_1): Print message when detaching
from inferior and '!is_fork_parent'.
gdb/testsuite/ChangeLog:
2018-04-24 Jan Kratochvil <jan.kratochvil@redhat.com>
Sergio Durigan Junior <sergiodj@redhat.com>
Pedro Alves <palves@redhat.com>
* gdb.base/attach-non-pgrp-leader.exp: Adjust 'Detaching...'
regexps to expect for '[Inferior ... detached]' as well.
* gdb.base/attach.exp: Likewise.
* gdb.base/catch-syscall.exp (check_for_program_end): Adjust
"gdb_continue_to_end".
(test_catch_syscall_with_wrong_args): Likewise.
* gdb.base/foll-fork.exp: Adjust regexps to match '[' and
']'. Don't set 'verbose' on.
* gdb.base/foll-vfork.exp: Likewise.
* gdb.base/fork-print-inferior-events.c: New file.
* gdb.base/fork-print-inferior-events.exp: New file.
* gdb.base/hook-stop.exp: Adjust regexps to expect for new
'[Inferior ... has been killed]' message.
* gdb.base/kill-after-signal.exp: Likewise.
* gdb.base/solib-overlap.exp: Adjust regexps to expect for new
detach message.
* gdb.threads/kill.exp: Adjust regexps to expect for new kill
message.
* gdb.threads/clone-attach-detach.exp: Adjust 'Detaching...'
regexps to expect for '[Inferior ... detached]' as well.
* gdb.threads/process-dies-while-detaching.exp: Likewise.
As reported in PR 23104, -ldl doesn't work on FreeBSD. Replace it with
shlib_load, which adds the right flags for dynamic library loading based
on the current target platform.
The test still passes on Linux, and should now pass on FreeBSD, though I
did not test personally.
gdb/testsuite/ChangeLog:
PR gdb/23104
* gdb.base/info-shared.exp: Replace libs=-ldl with shlib_load.
I noticed that cli-out.h had incorrect indentation in some spots.
This fixes it.
ChangeLog
2018-04-24 Tom Tromey <tom@tromey.com>
* cli-out.h: Reindent.
I noticed that cli_ui_out::out_field_fmt is only used by a single
caller, and it can easily be replaced by fputs_filtered. So, this
patch removes it.
ChangeLog
2018-04-24 Tom Tromey <tom@tromey.com>
* cli-out.c (cli_ui_out::out_field_fmt): Remove.
(cli_ui_out::do_field_string): Use fputs_filtered.
* cli-out.h (class cli_ui_out) <out_field_fmt>: Remove.
This removes a cleanup from scm-frame.c, replacing it with
unique_xmalloc_ptr and a new scope. I believe this also fixes a
latent bug involving calling do_cleanups twice for a single cleanup.
Regression tested using the gdb.guile test suite on x86-64 Fedora 26.
ChangeLog
2018-04-23 Tom Tromey <tom@tromey.com>
* guile/scm-frame.c (gdbscm_frame_read_var): Use
gdb::unique_xmalloc_ptr.
Pedro pointed out that gdb/configure and gdbserver/configure weren't
updated after some recent *.m4 changes.
This patch rebuilds those files. Tested by rebuilding. Pedro
approved this in the thread where he raised this issue, so I'm pushing
it in.
ChangeLog
2018-04-23 Tom Tromey <tom@tromey.com>
* configure: Rebuild.
gdbserver/ChangeLog
2018-04-23 Tom Tromey <tom@tromey.com>
* configure: Rebuild.
Problems:
1. linking -dl lib on FreeBSD platform
2. backtrace from ld-elf shows r_debug_state() instead of _dl_debug_state()
Cause:
1. There is no dl library on FreeBSD platform test has to ignore linking "-ldl"
2. The stop due to a shared library event shows backtrace frame #0
function as r_debug_state()
gdb/ChangeLog:
PR gdb/23095
* gdb/testsuite/gdb.base/break-probes.exp: Pass shlib_load to
prepare_for_testing. Set normal_bp to r_debug_state if target
is bsd.
As Rajendra SY reported at
<https://sourceware.org/ml/gdb-patches/2018-04/msg00399.html>, several
attach-related tests are failing on FreeBSD. The "attach" command
errors with "Couldn't get registers: Device busy".
When the "attach" command is executed, it calls target_attach ->
inf_ptrace_attach, which just does the ptrace(PT_ATTACH), it does not
wait for the child to stop with SIGSTOP. Afterwards, the command is
complete and we go back to the event loop. The event loop wakes up
and we end up in target_wait -> fbsd_wait, and handle the SIGSTOP
stop.
At the end of execute_command, though, before going back to the event
loop, we check if the frame language changed via
check_frame_language_change(). That reads the current PC, which is
what leads to the registers read that fails.
The problem is that we fail to mark the attached-to thread as
executing between the initial attach, and the subsequent target_wait.
Until we see the thread stop with SIGSTOP, we shouldn't try to read
registers off of it. I guess there may a timing issue here - if
you're "lucky", the thread may stop before gdb reads its registers,
masking the problem.
With that fixed, check_frame_language_change() becomes a nop until the
thread is marked not-executing again, after target_wait is called and
we go through handle_inferior_event -> normal_stop.
We haven't seen the problem on Linux because there, the target_attach
implementation waits for the thread to stop before returning. Still,
that's supposedly hidden from the core, since the Linux target, like
most targets, is a '!to_attach_no_wait' target.
This fixes:
FAIL: gdb.base/attach.exp: attach1, after setting file
FAIL: gdb.base/attach.exp: attach2, with no file
FAIL: gdb.base/attach.exp: load file manually, after attach2 (re-read) (got interactive prompt)
FAIL: gdb.base/attach.exp: attach when process' a.out not in cwd
FAIL: gdb.base/dprintf-detach.exp: bai=on ds=gdb dd=on: re-attach to inferior
FAIL: gdb.base/dprintf-detach.exp: bai=on ds=gdb dd=off: re-attach to inferior
FAIL: gdb.base/dprintf-detach.exp: bai=on ds=call dd=on: re-attach to inferior
FAIL: gdb.base/dprintf-detach.exp: bai=on ds=call dd=off: re-attach to inferior
FAIL: gdb.base/dprintf-detach.exp: bai=on ds=agent dd=on: re-attach to inferior
FAIL: gdb.base/dprintf-detach.exp: bai=on ds=agent dd=off: re-attach to inferior
FAIL: gdb.base/dprintf-detach.exp: bai=off ds=gdb dd=on: re-attach to inferior
FAIL: gdb.base/dprintf-detach.exp: bai=off ds=gdb dd=off: re-attach to inferior
FAIL: gdb.base/dprintf-detach.exp: bai=off ds=call dd=on: re-attach to inferior
FAIL: gdb.base/dprintf-detach.exp: bai=off ds=call dd=off: re-attach to inferior
FAIL: gdb.base/dprintf-detach.exp: bai=off ds=agent dd=on: re-attach to inferior
FAIL: gdb.base/dprintf-detach.exp: bai=off ds=agent dd=off: re-attach to inferior
gdb/ChangeLog:
2018-04-21 Pedro Alves <palves@redhat.com>
Rajendra SY <rajendra.sy@gmail.com>
* inf-ptrace.c (inf_ptrace_attach): Mark the thread as executing.
* remote.c (extended_remote_attach): In all-stop mode, mark the
thread as executing.
Add a Usage: line for thread_apply_command, in particular to mention
the thread ID list.
In thread_apply_command and thread_apply_all_command help, use
uppercase for arg names, as this style seems to be more standard.
2018-04-20 Philippe Waroquiers <philippe.waroquiers@skynet.be>
* thread.c (_initialize_thread): improve on-line help for
thread_apply_command and thread_apply_all_command.
The hang occurs when GDB tries to call inferior functions on two
different threads with scheduler-locking turned on. The first call works
fine, with the call to infrun_async(1) causing the signal_handler to be
marked and the event to be handled, but then the event loop resets the
"ready" member to zero, while leaving infrun_is_async set to 1. As a
result, GDB hangs if the user switches to another thread and calls a
second function because calling infrun_async(1) a second time has no
effect, meaning the inferior call events are never handled.
The added test case provokes the above issue.
gdb/testsuite/ChangeLog:
* gdb.threads/multiple-successive-infcall.c: New test.
* gdb.threads/multiple-successive-infcall.exp: New file.
Fix some typos.
Remove obsolete comment about dispatch to thread_apply_command,
rather tell that thread_command either switches to a thread,
or prints the current thread.
2018-04-19 Philippe Waroquiers <philippe.waroquiers@skynet.be>
* thread.c (thread_apply_all_command): Fix comment.
(thread_command): Fix comment.
The dependency tracking (the thing that knows which source file included
which other source file during last build to know what to rebuild when
an included file changes) is broken for gdbserver subdirectories (arch
and common).
The dependency tracking files are created in the form
arch/.deps/i386.Po
but we try to include
.deps/arch/i386.Po
An easy smoke test is too "touch" the gdb/features/i386/32bit-core.c
file in the source directory and try to rebuild gdbserver. This file is
included by gdb/arch/i386.c, so it should cause
gdb/gdbserver/arch/i386.o in the build directory to be rebuilt. It
currently isn't rebuilt, but is with this patch applied.
This patch copies the technique used in GDB to transform the dep file
paths to the proper form.
Also, while testing using the depcomp method of dependency tracking (by
just hacking the condition), I noticed that depcomp was not found. The
path to depcomp seems to be missing a "..".
gdb/gdbserver/ChangeLog:
* Makefile.in (depcomp): Add "..".
(all_deps_files): New and use it.
For ports which use new target descriptions, remove
the xml files from being built into gdbserver.
gdbserver/
* configure.srv (aarch64*-*-linux*): Don't include xml.
(i[34567]86-*-cygwin*): Likewise.
(i[34567]86-*-linux*): Likewise.
(i[34567]86-*-lynxos*): Likewise.
(i[34567]86-*-mingw32ce*): Likewise.
(i[34567]86-*-mingw*): Likewise.
(i[34567]86-*-nto*): Likewise.
(tic6x-*-uclinux): Likewise.
(x86_64-*-linux*): Likewise.
(x86_64-*-mingw*): Likewise.
(x86_64-*-cygwin*): Likewise.
Add a print_xml_feature visitor class which turns a
target description into xml. Both gdb and gdbserver can do this.
gdb/
* common/tdesc.c (print_xml_feature::visit_pre): Add xml parsing.
(print_xml_feature::visit_post): Likewise.
(print_xml_feature::visit): Likewise.
* common/tdesc.h (tdesc_get_features_xml): Use const tdesc.
(print_xml_feature): Add new class.
* regformats/regdat.sh: Null xmltarget on feature targets.
* target-descriptions.c (struct target_desc): Add xmltarget.
(maintenance_check_tdesc_xml_convert): Add unittest function.
(tdesc_get_features_xml): Add function to get xml.
(maintenance_check_xml_descriptions): Test xml generation.
* xml-tdesc.c (string_read_description_xml): Add function.
* xml-tdesc.h (string_read_description_xml): Add declaration.
gdbserver/
* gdb/gdbserver/server.c (get_features_xml): Remove cast.
* tdesc.c (void target_desc::accept): Fill in function.
(tdesc_get_features_xml): Remove old xml creation.
(print_xml_feature::visit_pre): Add xml vistor.
* tdesc.h (struct target_desc): Make xmltarget mutable.
(tdesc_get_features_xml): Remove declaration.
While debugging the crash that Jan reported, I noticed that in some
situations we could end up with a situation where one branch of a Rust
enum type ended up with a field count of -1.
The fix is simple: only conditionally drop the discriminant field when
rewriting the enum variants.
I couldn't find a way to test this; I only noticed it while debugging
the DWARF reader.
2018-04-17 Tom Tromey <tom@tromey.com>
* dwarf2read.c (quirk_rust_enum): Conditionally drop the
discriminant field.
I noticed that quirk_rust_enum can crash when presented with a union
whose fields are all scalar types.
This patch adds a new test case and fixes the bug.
Regression tested on Fedora 26 x86-64.
2018-04-17 Tom Tromey <tom@tromey.com>
* dwarf2read.c (quirk_rust_enum): Handle unions correctly.
2018-04-17 Tom Tromey <tom@tromey.com>
* gdb.rust/simple.rs (Union): New type.
(main): New local "u".
* gdb.rust/simple.exp (test_one_slice): Add new test case.
This commit:
b744723f57 -- Show line numbers in output for "info var/func/type"
adds the symbol declaration's line number to the output of certain GDB
commands. It also (inadvertently) changes the `rbreak' command's output,
like this:
(gdb) rbreak foo
Breakpoint 1 at 0x40049b: file rbreak.c, line 6.
4: static int foo1(void);
Breakpoint 2 at 0x4004b1: file rbreak.c, line 12.
10: static int foo2(void);
(gdb)
where the function declaration is now prefixed by its source line number,
followed by a colon. But without showing the declaration's file name, the
line number is useless and can possibly cause severe confusion.
No declaration line number was shown before. Instead, the function
declaration started at the first column:
(gdb) rbreak foo
Breakpoint 1 at 0x40049b: file rbreak.c, line 6.
static int foo1(void);
Breakpoint 2 at 0x4004b1: file rbreak.c, line 12.
static int foo2(void);
(gdb)
This old behavior is restored, fixing some FAILs in fullpath-expand.exp,
realname-expand.exp, and pr10179.exp.
In order to distinguish when to print location information, the meaning of
print_symbol_info()'s parameter `last' is changed. Now NULL means to skip
any filename or line number information. Previously NULL meant to always
print the filename.
gdb/ChangeLog:
* symtab.c (print_symbol_info): Skip printing filename and line
number when `last' is NULL.
(symtab_symbol_info): Use empty string instead of NULL for first
invocation of print_symbol_info.
(rbreak_command): Pass NULL to `last' parameter of
print_symbol_info.
Since commit
9018be2 ("Make target_read_alloc & al return vectors")
the test gdb.threads/gcore-stale-thread.exp test results in UNSUPPORTED:
UNSUPPORTED: gdb.threads/gcore-stale-thread.exp: save a corefile
The problem is that the linux_spu_make_corefile_notes started returning
nullptr when reading TARGET_OBJECT_SPU fails. The previous (and proper)
behaviour is to return the note_data received as a parameter, so that
other functions may continue to append to this buffer.
With this patch, the test goes back to PASS.
gdb/ChangeLog:
* linux-tdep.c (linux_spu_make_corefile_notes): Return note_data
instead of nullptr.
After this commit:
b744723f57 -- Show line numbers in output for "info var/func/type"
the test cases dbx.exp and info-fun.exp yield new FAILs because two
regular expressions have not been adjusted to the changed output yet.
This is fixed.
gdb/testsuite/ChangeLog:
* gdb.base/dbx.exp (test_whereis): Adjust regexp to added line
number information in output of "whereis" command.
* gdb.base/info-fun.exp: Likewise, for "info fun" command.
Since bfd dropped support for SH-5, there's no point in keeping it in
GDB either.
This restores --enable-targets=all builds.
gdb/ChangeLog:
2018-04-16 Pedro Alves <palves@redhat.com>
* MAINTAINERS (sh): Remove.
* Makefile.in (ALL_TARGET_OBS): Remove sh64-tdep.o.
(HFILES_NO_SRCDIR): Remove sh64-tdep.h.
(ALLDEPFILES): Remove sh64-tdep.c.
* NEWS: Mentions that support for SH-5/SH64 is removed.
* configure.tgt (sh*-*-linux*): Remove reference to sh64-tdep.o.
(sh*-*-openbsd*): Ditto.
(sh64-*-elf*): Remove.
(sh*): Remove.
* regcache.c (cooked_write_test): Remove bfd_mach_sh5 case.
* sh-linux-tdep.c: Remove reference to bfd_mach_sh5.
* sh-tdep.c: No longer include "sh64-tdep.h".
(sh_gdbarch_init): Remove reference to bfd_mach_sh5.
* sh64-tdep.c, sh64-tdep.h: Remove files.
Support for m88k was fully removed from bfd, which broke gdb
--enable-targets=all builds:
> gdb/m88k-tdep.c: In function void _initialize_m88k_tdep():
> gdb/m88k-tdep.c:867:21: error: bfd_arch_m88k was not declared in this scope
> gdbarch_register (bfd_arch_m88k, m88k_gdbarch_init, NULL);
There's no point in keeping GDB support for OpenBSD/m88k with no bfd
support, so this commit simply removes the port.
gdb/ChangeLog:
2018-04-16 Pedro Alves <palves@redhat.com>
* MAINTAINERS: Remove m88k.
* Makefile.in (ALL_TARGET_OBS): Remove m88k-tdep.o.
(HFILES_NO_SRCDIR): Remove m88k-tdep.h.
(ALLDEPFILES): Remove m88k-bsd-nat.c and m88k-tdep.c.
* NEWS: Mention that support for OpenBSD/m88k was removed.
* configure.host (m88*-*-*): Remove support.
* configure.nat (m88k-*-*): Remove support.
* configure.tgt (m88*-*-openbsd*): Remove.
* m88k-bsd-nat.c, m88k-tdep.c, m88k-tdep.h: Delete.
We get this error when doing a build with a single amd64 target (the
default when doing just ./configure on x86-64 GNU/Linux):
/home/simark/src/binutils-gdb/gdb/i386-tdep.c:4431: error: undefined reference to 'x86_in_indirect_branch_thunk(unsigned long, char const**, int, int)'
/home/simark/src/binutils-gdb/gdb/amd64-tdep.c:3045: error: undefined reference to 'x86_in_indirect_branch_thunk(unsigned long, char const**, int, int)'
The problem is that commit
1d509aa625 ("infrun: step through indirect branch thunks")
missed adding x86-tdep.o to the list of object file included in an amd64
or i386 build. The problem is not seen with --enable-targets=all
because that file is included in ALL_TARGET_OBS.
Built-tested using:
* --host=x86_64-pc-linux-gnu --target=x86_64-pc-linux-gnu
* --host=armv7-rpi2-linux-gnueabihf --target=x86_64-pc-linux-gnu
gdb/ChangeLog:
* configure.tgt (x86_tobjs): New variable.
(amd64_tobjs, i386_tobjs): Use it.
The GDB commands "info variables", "info functions", and "info types" show
the appropriate list of definitions matching the given pattern. They also
group them by source files. But no line numbers within these source files
are shown.
The line number information is particularly useful to the user when a
simple "grep" doesn't readily point to a definition. This is often the
case when the definition involves a macro, occurs within a namespace, or
when the identifier appears very frequently in the source file.
This patch enriches the printout of these commands by the line numbers and
adjusts affected test cases to the changed output where necessary. The
new output looks like this:
(gdb) i variables
All defined variables:
File foo.c:
3: const char * const foo;
1: int x;
The line number is followed by a colon and a tab character, which is then
followed by the symbol definition. If no line number is available, the
tab is printed out anyhow, so definitions line up.
gdb/ChangeLog:
* symtab.c (print_symbol_info): Precede the symbol definition by
the line number when available.
* NEWS: Advertise this enhancement.
gdb/doc/ChangeLog:
* gdb.texinfo (Symbols): Mention the fact that "info
variables/functions/types" show source files and line numbers.
gdb/testsuite/ChangeLog:
* gdb.ada/info_types.exp: Adjust expected output to the line
numbers now printed by "info var/func/type".
* gdb.base/completion.exp: Likewise.
* gdb.base/included.exp: Likewise.
* gdb.cp/cp-relocate.exp: Likewise.
* gdb.cp/cplusfuncs.exp: Likewise.
* gdb.cp/namespace.exp: Likewise.
* gdb.dwarf2/dw2-case-insensitive.exp: Likewise.
Add new set/show commands to set the processor that is used for enabling
errata workarounds when decoding branch trace.
The general format is "<vendor>:<identifier>" but we also allow two
special values "auto" and "none".
The default is "auto", which is the current behaviour of having GDB
determine the processor on which the trace was recorded.
If that cpu is not known to the trace decoder, e.g. when using an old
decoder on a new system, decode may fail with "unknown cpu". In most
cases it should suffice to 'downgrade' decode to assume an older cpu.
Unfortunately, we can't do this automatically.
The other special value, "none", disables errata workarounds.
gdb/
* NEWS (New options): announce set/show record btrace cpu.
* btrace.c: Include record-btrace.h.
(btrace_compute_ftrace_pt): Skip enabling errata workarounds if
the vendor is unknown.
(btrace_compute_ftrace_1): Add cpu parameter. Update callers.
Maybe overwrite the btrace configuration's cpu.
(btrace_compute_ftrace): Add cpu parameter. Update callers.
(btrace_fetch): Add cpu parameter. Update callers.
(btrace_maint_update_pt_packets): Call record_btrace_get_cpu.
Maybe overwrite the btrace configuration's cpu. Skip enabling
errata workarounds if the vendor is unknown.
* python/py-record-btrace.c: Include record-btrace.h.
(recpy_bt_begin, recpy_bt_end, recpy_bt_instruction_history)
(recpy_bt_function_call_history): Call record_btrace_get_cpu.
* record-btrace.c (record_btrace_cpu_state_kind): New.
(record_btrace_cpu): New.
(set_record_btrace_cpu_cmdlist): New.
(record_btrace_get_cpu): New.
(require_btrace_thread, record_btrace_info)
(record_btrace_resume_thread): Call record_btrace_get_cpu.
(cmd_set_record_btrace_cpu_none): New.
(cmd_set_record_btrace_cpu_auto): New.
(cmd_set_record_btrace_cpu): New.
(cmd_show_record_btrace_cpu): New.
(_initialize_record_btrace): Initialize set/show record btrace cpu
commands.
* record-btrace.h (record_btrace_get_cpu): New.
testsuite/
* gdb.btrace/cpu.exp: New.
doc/
* gdb.texinfo: Document set/show record btrace cpu.
Alan Hayward pointed out a typo in the output of "set record btrace" that
I took from "set record". Fix the original.
gdb/
* record.c (set_record_command): Fix typo in message.
Instead of giving a message that "set record btrace" needs a sub-command,
GDB crashed. Fix it. A regression test comes with the next patch.
gdb/
* record-btrace.c (cmd_set_record_btrace): Print sub-commands.
With version 7.3 GCC supports new options
-mindirect-branch=<choice>
-mfunction-return=<choice>
The choices are:
keep behaves as before
thunk jumps through a thunk
thunk-external jumps through an external thunk
thunk-inline jumps through an inlined thunk
For thunk and thunk-external, GDB would, on a call to the thunk, step into
the thunk and then resume to its caller assuming that this is an
undebuggable function. On a return thunk, GDB would stop inside the
thunk.
Make GDB step through such thunks instead.
Before:
Temporary breakpoint 1, main ()
at gdb.base/step-indirect-call-thunk.c:37
37 x = apply (inc, 41);
(gdb) s
apply (op=0x80483e6 <inc>, x=41)
at gdb.base/step-indirect-call-thunk.c:29
29 return op (x);
(gdb)
30 }
After:
Temporary breakpoint 1, main ()
at gdb.base/step-indirect-call-thunk.c:37
37 x = apply (inc, 41);
(gdb) s
apply (op=0x80483e6 <inc>, x=41)
at gdb.base/step-indirect-call-thunk.c:29
29 return op (x);
(gdb)
inc (x=41) at gdb.base/step-indirect-call-thunk.c:23
23 return x + 1;
This is independent of the step-mode. In order to step into the thunk,
you would need to use stepi.
When stepping over an indirect call thunk, GDB would first step through
the thunk, then recognize that it stepped into a sub-routine and resume to
the caller (of the thunk). Not sure whether this is worth optimizing.
Thunk detection is implemented via gdbarch. I implemented the methods for
IA. Other architectures may run into unexpected fails.
The tests assume a fixed number of instruction steps to reach a thunk.
This depends on the compiler as well as the architecture. They may need
adjustments when we add support for more architectures. Or we can simply
drop those tests that cover being able to step into thunks using
instruction stepping.
When using an older GCC, the tests will fail to build and will be reported
as untested:
Running .../gdb.base/step-indirect-call-thunk.exp ...
gdb compile failed, \
gcc: error: unrecognized command line option '-mindirect-branch=thunk'
gcc: error: unrecognized command line option '-mfunction-return=thunk'
=== gdb Summary ===
# of untested testcases 1
gdb/
* infrun.c (process_event_stop_test): Call
gdbarch_in_indirect_branch_thunk.
* gdbarch.sh (in_indirect_branch_thunk): New.
* gdbarch.c: Regenerated.
* gdbarch.h: Regenerated.
* x86-tdep.h: New.
* x86-tdep.c: New.
* Makefile.in (ALL_TARGET_OBS): Add x86-tdep.o.
(HFILES_NO_SRCDIR): Add x86-tdep.h.
(ALLDEPFILES): Add x86-tdep.c.
* arch-utils.h (default_in_indirect_branch_thunk): New.
* arch-utils.c (default_in_indirect_branch_thunk): New.
* i386-tdep: Include x86-tdep.h.
(i386_in_indirect_branch_thunk): New.
(i386_elf_init_abi): Set in_indirect_branch_thunk gdbarch
function.
* amd64-tdep: Include x86-tdep.h.
(amd64_in_indirect_branch_thunk): New.
(amd64_init_abi): Set in_indirect_branch_thunk gdbarch function.
testsuite/
* gdb.base/step-indirect-call-thunk.exp: New.
* gdb.base/step-indirect-call-thunk.c: New.
* gdb.reverse/step-indirect-call-thunk.exp: New.
* gdb.reverse/step-indirect-call-thunk.c: New.
Andrzej Kaczmarek