shellcheck reports:
In gdbarch.sh line 139:
fallbackdefault="0"
^-------------^ SC2034: fallbackdefault appears unused. Verify use (or export if used externally).
Indeed, the `fallbackdefault` variable appears to be unused, remove the
code that sets it.
gdb/ChangeLog:
* gdbarch.sh: Remove code that sets fallbackdefault.
Fix all warnings of this type:
In gdbarch.sh line 1238:
if [ "x${invalid_p}" = "x0" -a -n "${postdefault}" ]
^-- SC2166: Prefer [ p ] && [ q ] as [ p -a q ] is not well defined.
See the rationale here [1].
[1] https://github.com/koalaman/shellcheck/wiki/SC2166
gdb/ChangeLog:
* gdbarch.sh: Use shell operators && and || instead of
-a and -o.
Fix all instances of:
In gdbarch.sh line 2195:
printf " `echo "$function" | sed -e 's/./ /g'` %s %s)\n" "$returntype" "$function"
^-- SC2006: Use $(...) notation instead of legacy backticked `...`.
Did you mean:
printf " $(echo "$function" | sed -e 's/./ /g') %s %s)\n" "$returntype" "$function"
See here [1] for the rationale.
[1] https://github.com/koalaman/shellcheck/wiki/SC2006
gdb/ChangeLog:
* gdbarch.sh: Use $(...) instead of `...`.
Fix all instances of:
In gdbarch.sh line 31:
if test ! -r ${file}
^-----^ SC2086: Double quote to prevent globbing and word splitting.
Did you mean:
if test ! -r "${file}"
Note that some instances of these are in text that is eval'ed. I'm
pretty sure that things could go wrong during the eval too, but that's
not something shellcheck can check.
gdb/ChangeLog:
* gdbarch.sh: Use double quotes around variables.
Fix all instances of this:
In gdbarch.sh line 2182:
printf " gdb_assert (!(${invalid_p}));\n"
^-- SC2059: Don't use variables in the printf format string. Use printf "..%s.." "$foo".
... by doing exactly as the message suggests.
The rationale explained here [1] makes sense, if there happens to be a
format specifier in text substituted for the variable, the printf won't
do what we expect.
[1] https://github.com/koalaman/shellcheck/wiki/SC2059
gdb/ChangeLog:
* gdbarch.sh: Use %s with printf, instead of variables in the
format string.
These test names are duplicated:
2 PASS: gdb.base/break.exp: set breakpoint via non-integer convenience variable disallowed
2 PASS: gdb.base/break.exp: set convenience variable $foo to 81.5
Wrap them with `with_test_prefix`. I've actually wrapped a bit more
tests that are related, I think it helps to give the test names a bit
more context. The modified test names are:
-PASS: gdb.base/break.exp: set convenience variable $foo to bp_location11
-PASS: gdb.base/break.exp: set breakpoint via convenience variable
-PASS: gdb.base/break.exp: set convenience variable $foo to 81.5
-PASS: gdb.base/break.exp: set breakpoint via non-integer convenience variable disallowed
+PASS: gdb.base/break.exp: set line breakpoint via convenience variable: set convenience variable $foo to bp_location11
+PASS: gdb.base/break.exp: set line breakpoint via convenience variable: break $foo
+PASS: gdb.base/break.exp: set line breakpoint via convenience variable: set convenience variable $foo to 81.5
+PASS: gdb.base/break.exp: set line breakpoint via convenience variable: non-integer convenience variable disallowed
-PASS: gdb.base/break.exp: set $l = 47
-PASS: gdb.base/break.exp: break break.c:$l
-PASS: gdb.base/break.exp: set convenience variable $foo to 81.5
-PASS: gdb.base/break.exp: set breakpoint via non-integer convenience variable disallowed
+PASS: gdb.base/break.exp: set line:file breakpoint via convenience variable: set $l = 47
+PASS: gdb.base/break.exp: set line:file breakpoint via convenience variable: break break.c:$l
+PASS: gdb.base/break.exp: set line:file breakpoint via convenience variable: set convenience variable $foo to 81.5
+PASS: gdb.base/break.exp: set line:file breakpoint via convenience variable: non-integer convenience variable disallowed
gdb/testsuite/ChangeLog:
* gdb.base/break.exp: Use with_test_prefix.
PR ada/25875 concerns a gdb crash when gdb.ada/arr_enum_idx_w_gap.exp
is run using the .debug_types board.
The problem turns out to be caused by weird compiler output. In this
test, the compiler emits a top-level type that refers to an
enumeration type which is nested in a function. However, this
function is just a declaration.
This results in gdb calling read_enumeration_type for the enum type,
but process_enumeration_scope is never called, yielding an enum with
no fields. This causes the crash.
This patch fixes the problem by arranging to create the enum fields in
read_enumeration_type.
Tested on x86-64 Fedora 30.
gdb/ChangeLog
2020-04-29 Tom Tromey <tromey@adacore.com>
PR ada/25875:
* dwarf2/read.c (update_enumeration_type_from_children): Compute
type fields here.
(read_enumeration_type): Call
update_enumeration_type_from_children later. Update comments.
(process_enumeration_scope): Don't create type fields.
The syscall literal names are not stable on NetBSD and can change
once a syscall is versioned. Thus these names are internal to the
system and in GDB mostly descriptive, not intended to be a stable
interface with fixed names across GDB and NetBSD versions to track
certain syscalls.
gdb/ChangeLog:
* nbsd-tdep.c: Include "xml-syscall.h".
(nbsd_init_abi): Call `set_xml_syscall_file_name'.
Implement the following events:
- single step (TRAP_TRACE)
- software breakpoint (TRAP_DBREG)
- exec() (TRAP_EXEC)
- syscall entry/exit (TRAP_SCE / TRAP_SCX)
Add support for NetBSD specific ::wait () and ::resume ().
Instruct the generic code that exec and syscall events are supported.
Define an empty nbsd_get_syscall_number as it is prerequisite for
catching syscall entry and exit events, even if it is unused.
This function is used to detect whether the gdbarch supports the
'catch syscall' feature.
gdb/ChangeLog:
* nbsd-nat.c: Include "sys/wait.h".
(nbsd_resume, nbsd_nat_target::resume, nbsd_wait)
(nbsd_nat_target::wait, nbsd_nat_target::insert_exec_catchpoint)
(nbsd_nat_target::remove_exec_catchpoint)
(nbsd_nat_target::set_syscall_catchpoint): Add.
* nbsd-nat.h (nbsd_nat_target::resume, nbsd_nat_target::wait)
(nbsd_nat_target::insert_exec_catchpoint)
(nbsd_nat_target::remove_exec_catchpoint)
(nbsd_nat_target::set_syscall_catchpoint): Add.
* nbsd-tdep.c (nbsd_get_syscall_number): Add.
(nbsd_init_abi): Call `set_gdbarch_get_syscall_number' and pass
`nbsd_get_syscall_number'.
* readelf.c (warn): New function - like elfcomm.c version but only
produces output if warnings are enabled.
(struct options): Add --lint and --enable-checks.
(usage): Add entry for --lint.
(parse_args): Handle -L. If checks are enabled but no dumps have
been selected then enable all dumps.
(process_section_headers): Replace long if-then-else sequence with
a switch. Add warning messages for empty SHT_REL, SHT_RELA and
SHT_PROGBITS sections.
(process_file): Do not complain if the file is an archive and lint
mode has been enabled.
* elfcomm.c (error): Make the function weak.
(warn): Likewise.
* NEWS: Mention the new feature.
* doc/binutils.texi: Document the new feature.
* dwarf.h (report_leb_status): Add file name and line number
parameters. Include them in the diagnostic output.
(READ_ULEB): Pass file and line number to report_leb_status.
(READ_SLEB): Likewise.
* dwarf.c (read_and_print_leb128): Pass file and line number to
report_leb_status.
* testsuite/binutils-all/readelf.exp: Add test of new feature.
* testsuite/binutils-all/zero-sec.s: New test source file.
* testsuite/binutils-all/zero-sec.r: Expected output from new
test.
print_block_frame_labels has been commented out since 2010.
I don't think we need it; this patch removes it.
2020-04-29 Tom Tromey <tom@tromey.com>
* stack.c (print_block_frame_labels): Remove.
PR 22699
opcodes * sh-opc.h (IMM0_8): Replace with IMM0_8S and IMM0_8U. Use
IMM0_8S for arithmetic insns and IMM0_8U for logical insns.
* sh-dis.c (print_insn_sh): Change IMM0_8 case to IMM0_8S and add
IMM0_8U case.
gas * config/tc-sh.c (build_Mytes): Change operand type IMM0_8 to
IMM0_8S and add support for IMM0_8U.
* testsuite/gas/sh/sh4a.s: Add test of a logical insn using an
unsigned 8-bit immediate.
* testsuite/gas/sh/sh4a.d: Extended expected disassembly.
PR 25829
* testsuite/ld-scripts/default-script.exp: Add --image-base=0 to
LDFLAGS for targets *-*-mingw64 x86_64-*-cygwin.
* testsuite/ld-scripts/default-script1.d: No longer have to skip
test for those targets.
* testsuite/ld-scripts/default-script2.d: Likewise.
* testsuite/ld-scripts/default-script3.d: Likewise.
* testsuite/ld-scripts/default-script4.d: Likewise.
With target board debug-types, we have these FAILs:
...
FAIL: gdb.guile/scm-symtab.exp: test simple_struct in static symbols
FAIL: gdb.python/py-symtab.exp: test simple_struct in static symbols
...
due to PR gcc/90232, as explained in commit 15cd93d05e "[gdb/symtab] Handle
struct decl with DW_AT_signature".
Marks these as XFAILs.
Tested on x86_64-linux.
gdb/testsuite/ChangeLog:
2020-04-29 Tom de Vries <tdevries@suse.de>
* lib/gdb.exp (debug_types): New proc.
* gdb.guile/scm-symtab.exp: Add xfail for PR gcc/90232.
* gdb.python/py-symtab.exp: Same.
Currently, printing with array pretty formatting makes the output actually
less readable than without:
(gdb) p -array on -- {{1,2,3},{4,5,6}}
$1 = { {1,
2,
3},
{4,
5,
6}}
(gdb) p -array on -array-indexes on -- {{1,2,3},{4,5,6}}
$2 = {[0] = {[0] = 1,
[1] = 2,
[2] = 3},
[1] = {[0] = 4,
[1] = 5,
[2] = 6}}
These changes now also put the first element and the array end bracket on a new
line, similar to the structure pretty formatter:
(gdb) p -array on -- {{1,2,3},{4,5,6}}
$1 = {
{
1,
2,
3
},
{
4,
5,
6
}
}
(gdb) p -array on -array-indexes on -- {{1,2,3},{4,5,6}}
$2 = {
[0] = {
[0] = 1,
[1] = 2,
[2] = 3
},
[1] = {
[0] = 4,
[1] = 5,
[2] = 6
}
}
gdb/ChangeLog:
2020-04-29 Hannes Domani <ssbssa@yahoo.de>
PR gdb/17320
* ada-valprint.c (val_print_packed_array_elements): Move array
end bracket to new line.
(ada_val_print_string): Remove extra spaces before first array
element.
* c-valprint.c (c_value_print_array): Likewise.
* m2-valprint.c (m2_print_array_contents): Likewise.
(m2_value_print_inner): Likewise.
* p-valprint.c (pascal_value_print_inner): Likewise.
* valprint.c (generic_val_print_array): Likewise.
(value_print_array_elements): Move first array element and array
end bracket to new line.
gdb/testsuite/ChangeLog:
2020-04-29 Hannes Domani <ssbssa@yahoo.de>
PR gdb/17320
* gdb.base/pretty-array.c: New test.
* gdb.base/pretty-array.exp: New file.
With target board debug-types, we have:
...
FAIL: gdb.cp/cpexprs.exp: list policy1::function
...
This is a regression triggered by commit 770479f223 "gdb: Fix toplevel types
with -fdebug-types-section".
However, the FAIL is caused by commit 4dedf84da9 "Change
decode_compound_collector to use std::vector" which changes a VEC_iterate loop
into a range loop:
...
- for (ix = 0; VEC_iterate (symbolp, sym_classes, ix, sym); ++ix)
+ unsigned int ix = 0;
+ for (const auto &sym : *sym_classes)
...
but fails to ensure that the increment of ix happens every iteration.
Fix this by calculating the index variable at the start of the loop body:
...
for (const auto &elt : *sym_classes)
{
unsigned int ix = &elt - &*sym_classes->begin ();
...
Tested on x86_64-linux, with native and target board debug-types.
gdb/ChangeLog:
2020-04-29 Tom de Vries <tdevries@suse.de>
PR symtab/25889
* linespec.c (find_method): Fix ix calculation.
gdb/testsuite/ChangeLog:
2020-04-29 Tom de Vries <tdevries@suse.de>
PR symtab/25889
* gdb.cp/cpexprs.exp: Adapt for inclusion.
* gdb.cp/cpexprs-debug-types.exp: New file. Set -fdebug-types-section
and include cpexprs.exp.
All platforms on NetBSD use a shared system call table, so use a
single XML file to describe the system calls available on each NetBSD
platform.
gdb/ChangeLog:
* syscalls/update-netbsd.sh: New file.
* syscalls/netbsd.xml: Regenerate.
* data-directory/Makefile.in: Register `netbsd.xml' in
`SYSCALLS_FILES'
shellcheck reports:
In update-freebsd.sh line 72:
}' $1 >> freebsd.xml.tmp
^-- SC2086: Double quote to prevent globbing and word splitting.
Did you mean:
}' "$1" >> freebsd.xml.tmp
For more information:
https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...
Add double quotes to fix it.
gdb/ChangeLog:
* syscalls/update-freebsd.sh: Add double quotes.
Now that Python code can create TUI windows, it seemed appropriate to
allow Python commands to appear in the "TUI" help class. This patch
adds this capability.
gdb/ChangeLog
2020-04-28 Tom Tromey <tom@tromey.com>
* NEWS: Update.
* python/py-cmd.c (gdbpy_initialize_commands): Add COMMAND_TUI.
(cmdpy_init): Allow class_tui.
gdb/doc/ChangeLog
2020-04-28 Tom Tromey <tom@tromey.com>
* python.texi (Commands In Python): Document gdb.COMMAND_TUI.
When debugging a program compiled with -fdebug-types-section,
only the first top-level type in each file is visible to gdb.
The problem was caused by moving the assignment to list_in_scope
from process_full_comp_unit and process_full_type_unit to
start_symtab. This was fine for process_full_comp_unit, because
symtabs and comp units are one-to-one. But there can be many type
units per symtab (one for each type), and we only call start_symtab
for the first one. This adds the necessary assignments on the paths
where start_symtab is not called.
gdb/Changelog:
2020-04-28 Mark Williams <mark@myosotissp.com>
PR gdb/24480
* dwarf2read.c: Add missing assingments to list_in_scope when
start_symtab was already called.
gdb/testsuite/Changelog:
2020-04-28 Mark Williams <mark@myosotissp.com>
PR gdb/24480
* dw4-toplevel-types.exp: Test for top level types.
* dw4-toplevel-types.cc: Test for top level types.
When building with g++ 4.8, we get this error (just an excerpt, because
g++ outputs a very long error message):
CXX dwarf2/read.o
...
/home/smarchi/src/binutils-gdb/gdb/dwarf2/read.c:14616:31: required from here
/usr/include/c++/4.8/bits/hashtable_policy.h:1070:12: error: invalid use of incomplete type ‘struct std::hash<sect_offset>’
struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2,
This is the same problem and fix as in commit f23f598e28 ("[gdb] Fix
build breaker with gcc 4.8"). Pass an explicit hash function rather
than relying on the default std::hash<sect_offset>.
gdb/ChangeLog:
PR gdb/25881
* dwarf2/read.c (offset_map_type): Use
gdb:hash_enum<sect_offset> as hash function.
With test-case gdb.opt/inline-cmds.exp, we have:
...
KFAIL: gdb.opt/inline-cmds.exp: next to second func1 (PRMS: gdb/NNNN)
...
I've filed PR25884 for this failure.
Set the KFAIL PR accordingly.
gdb/testsuite/ChangeLog:
2020-04-28 Tom de Vries <tdevries@suse.de>
* gdb.opt/inline-cmds.exp: Set KFAIL PR.
When running test-case gdb.base/info-macros.exp, we have:
...
(gdb) KFAIL: gdb.base/info-macros.exp: info macros info-macros.c:42 \
(PRMS: gdb/NNNN)
...
The described failure mode however:
...
set test "info macros info-macros.c:42"
set r1 ".*define DEF_MACROS"
set r2 ".*define ONE"
setup_kfail "gdb/NNNN" *-*-*
gdb_test "$test" "$r1$r2"
...
does not match the actual output, given that both defines are in fact
printed.
The pattern fails to match because it's missing a trailing ".*".
Fix this by removing the KFAIL and adding the missing trailing ".*".
Tested on x86_64-linux.
gdb/testsuite/ChangeLog:
2020-04-28 Tom de Vries <tdevries@suse.de>
* gdb.base/info-macros.exp: Remove KFAIL. Add missing trailing ".*".
When running test-case gdb.ada/array_ptr_renaming.exp we run into:
...
(gdb) print ntp^M
$3 = (3 => 30, 40)^M
(gdb) KFAIL: gdb.ada/array_ptr_renaming.exp: print ntp (PRMS: gdb/NNNN)
...
I've opened PR25883 for this failure. Reference the PR from the KFAIL, such
that we have:
...
KFAIL: gdb.ada/array_ptr_renaming.exp: print ntp (PRMS: gdb/25883)
...
gdb/testsuite/ChangeLog:
2020-04-28 Tom de Vries <tdevries@suse.de>
* gdb.ada/array_ptr_renaming.exp: Add PR number in KFAIL.
Consider a test-case with sources 36.c:
...
struct s { int i; };
extern void f (void);
int main (void) {
struct s a;
f ();
return 0;
}
...
and 36b.c:
...
struct s { int j; };
void f (void) {
struct s b;
}
...
compiled like this:
...
$ gcc 36.c 36b.c -g
...
It contains DWARF like this:
...
<0><d2>: Abbrev Number: 1 (DW_TAG_compile_unit)
<d8> DW_AT_name : 36.c
<1><f4>: Abbrev Number: 2 (DW_TAG_structure_type)
<f5> DW_AT_name : s
<2><fe>: Abbrev Number: 3 (DW_TAG_member)
<ff> DW_AT_name : i
<1><110>: Abbrev Number: 5 (DW_TAG_subprogram)
<111> DW_AT_name : main
<2><12d>: Abbrev Number: 6 (DW_TAG_variable)
<12e> DW_AT_name : a
<132> DW_AT_type : <0xf4>
<0><146>: Abbrev Number: 1 (DW_TAG_compile_unit)
<14c> DW_AT_name : 36b.c
<1><168>: Abbrev Number: 2 (DW_TAG_structure_type)
<169> DW_AT_name : s
<2><172>: Abbrev Number: 3 (DW_TAG_member)
<173> DW_AT_name : j
<1><184>: Abbrev Number: 5 (DW_TAG_subprogram)
<185> DW_AT_name : f
<2><19b>: Abbrev Number: 6 (DW_TAG_variable)
<19c> DW_AT_name : b
<1a0> DW_AT_type : <0x168>
...
And when printing "struct s", we get first a random one (with int j), and then
context-specific ones (with int i in main, and int j in f):
...
$ gdb -batch a.out \
-ex "ptype struct s" \
-ex start \
-ex "ptype struct s" \
-ex "break f" -ex continue \
-ex "ptype struct s" \
| grep "int [ij];"
int j;
int i;
int j;
...
Same for -readnow.
However, if we use -fdebug-types-section:
...
$ gcc 36.c 36b.c -g -fdebug-types-section
...
we get:
...
$ gdb ... | grep "int [ij];"
int j;
int i;
int i;
$ gdb -readnow ... | grep "int [ij];"
int j;
int j;
int j;
...
This is due to the fact that both "struct s" DIEs have been moved to the
.debug_types section:
...
Compilation Unit @ offset 0x0:
Signature: 0xfd1462823bb6f7b7
<0><17>: Abbrev Number: 1 (DW_TAG_type_unit)
<1><1d>: Abbrev Number: 2 (DW_TAG_structure_type)
<1e> DW_AT_name : s
<2><27>: Abbrev Number: 3 (DW_TAG_member)
<28> DW_AT_name : i
Compilation Unit @ offset 0x3a:
Signature: 0x534310fbefba324d
<0><51>: Abbrev Number: 1 (DW_TAG_type_unit)
<1><57>: Abbrev Number: 2 (DW_TAG_structure_type)
<58> DW_AT_name : s
<2><61>: Abbrev Number: 3 (DW_TAG_member)
<62> DW_AT_name : j
...
and there's no longer a "struct s" DIE in the 36.c and
and 36b.c CUs to specify which "struct s" belongs in the CU. This is gcc
PR90232.
However, using a tentative patch for gcc that adds these DIEs (according to
DWARF standard: If the complete declaration of a type has been placed in a
separate type unit, an incomplete declaration of that type in the compilation
unit may provide the unique 64-bit signature of the type using a
DW_AT_signature attribute):
...
<0><d2>: Abbrev Number: 5 (DW_TAG_compile_unit)
<d8> DW_AT_name : 36.c
+ <1><f4>: Abbrev Number: 6 (DW_TAG_structure_type)
+ <f5> DW_AT_name : s
+ <f7> DW_AT_signature : signature: 0xfd1462823bb6f7b7
+ <ff> DW_AT_declaration : 1
<0><13c>: Abbrev Number: 5 (DW_TAG_compile_unit)
<142> DW_AT_name : 36b.c
+ <1><15e>: Abbrev Number: 6 (DW_TAG_structure_type)
+ <15f> DW_AT_name : s
+ <161> DW_AT_signature : signature: 0x534310fbefba324d
+ <169> DW_AT_declaration : 1
...
still does not help, because they're declarations, so new_symbol is not called
for them in process_structure_scope.
Fix this by calling new_symbol for these decls.
Build and tested on x86_64-linux.
Also tested with target board enabling by default -fdebug-types-section
-gdwarf-4, and with gcc with aforementioned tentative patch. In this
configuration, the patch reduces number of FAILs from 2888 to 238.
gdb/ChangeLog:
2020-04-28 Tom de Vries <tdevries@suse.de>
* dwarf2/read.c (process_structure_scope): Add symbol for struct decl
with DW_AT_signature.
gdb/testsuite/ChangeLog:
2020-04-28 Tom de Vries <tdevries@suse.de>
* gdb.dwarf2/main-foo.c: New test.
* gdb.dwarf2/struct-with-sig.exp: New file.
The zero check was on the wrong operand. And, yes, the second operand
popped is supposed to be divided by the first operand popped.
* vms-alpha.c (_bfd_vms_slurp_etir): Correct divide by zero check.
Emit warning message.
The 64-bit version of binutils got support for the PE COFF BIG OBJ format a
couple of years ago. The BIG OBJ format is a slightly different COFF format
which extends the size of the number of section field in the header from a
uint16_t to a uint32_t and so greatly increases the number of sections allowed.
However the 32-bit version of bfd never got support for this. The GHC Haskell
compiler generates a great deal of symbols due to it's use of
-ffunction-sections and -fdata-sections.
This meant that we could not build the 32-bit version of the GHC Compiler for
many releases now as binutils didn't have this support.
This patch adds the support to the 32-bit port of binutils as well and also does
come cleanup in the code.
bfd/ChangeLog:
* coff-i386.c (COFF_WITH_PE_BIGOBJ): New.
* coff-x86_64.c (COFF_WITH_PE_BIGOBJ): New.
* config.bfd (targ_selvecs): Rename x86_64_pe_be_vec
to x86_64_pe_big_vec as it not a big-endian format.
(vec i386_pe_big_vec): New.
* configure.ac: Likewise.
* targets.c: Likewise.
* configure: Regenerate.
* pe-i386.c (TARGET_SYM_BIG, TARGET_NAME_BIG,
COFF_WITH_PE_BIGOBJ): New.
* pe-x86_64.c (TARGET_SYM_BIG, TARGET_NAME_BIG):
New.
(x86_64_pe_be_vec): Moved.
gas/ChangeLog:
* NEWS: Add news entry for big-obj.
* config/tc-i386.c (i386_target_format): Support new format.
* doc/c-i386.texi: Add i386 support.
* testsuite/gas/pe/big-obj.d: Rename test to not be x64 specific.
* testsuite/gas/pe/pe.exp (big-obj): Make test run on i386 as well.
ld/ChangeLog:
* pe-dll.c (pe_detail_list): Add pe-bigobj-i386.
I recently stumbled on this code mentioning Linux kernel 2.6.25, and
thought it could be time for some spring cleaning (newer GDBs probably
don't need to supports 12-year old kernels). I then found that the
"legacy" case is probably broken anyway, which gives an even better
motivation for its removal.
In short, this patch removes the configure checks that check if
user_regs_struct contains the fs_base/gs_base fields and adjusts all
uses of the HAVE_STRUCT_USER_REGS_STRUCT_{FS,GS}_BASE macros. The
longer explanation/rationale follows.
Apparently, Linux kernels since 2.6.25 (that's from 2008) have been
reliably providing fs_base and gs_base as part of user_regs_struct.
Commit df5d438e33d7 in the Linux kernel [1] seems related. This means
that we can get these values by reading registers with PTRACE_GETREGS.
Previously, these values were obtained using a separate
PTRACE_ARCH_PRCTL ptrace call.
First, I'm not even sure the configure check was really right in the
first place.
The user_regs_struct used by GDB comes from
/usr/include/x86_64-linux-gnu/sys/user.h (or equivalent on other
distros) and is provided by glibc. glibc has had the fs_base/gs_base
fields in there for a very long time, at least since this commit from
2001 [2]. The Linux kernel also has its version of user_regs_struct,
which I think was exported to user-space at some point. It included the
fs_base/gs_base fields since at least this 2002 commit [3]. In any
case, my conclusion is that the fields were there long before the
aforementioned Linux kernel commit. The kernel commit didn't add these
fields, it only made sure that they have reliable values when obtained
with PTRACE_GETREGS.
So, checking for the presence of the fs_base/gs_base fields in struct
user_regs_struct doesn't sound like a good way of knowing if we can
reliably get the fs_base/gs_base values from PTRACE_GETREGS. My guess
is that if we were using that strategy on a < 2.6.25 kernel, things
would not work correctly:
- configure would find that the user_regs_struct has the fs_base/gs_base
fields (which are probided by glibc anyway)
- we would be reading the fs_base/gs_base values using PTRACE_GETREGS,
for which the kernel would provide unreliable values
Second, I have tried to see how things worked by forcing GDB to not use
fs_base/gs_base from PTRACE_GETREGS (forcing it to use the "legacy"
code, by configuring with
ac_cv_member_struct_user_regs_struct_gs_base=no ac_cv_member_struct_user_regs_struct_fs_base=no
Doing so breaks writing registers back to the inferior. For example,
calling an inferior functions gives an internal error:
(gdb) p malloc(10)
/home/smarchi/src/binutils-gdb/gdb/i387-tdep.c:1408: internal-error: invalid i387 regnum 152
The relevant last frames where this error happens are:
#8 0x0000563123d262fc in internal_error (file=0x563123e93fd8 "/home/smarchi/src/binutils-gdb/gdb/i387-tdep.c", line=1408, fmt=0x563123e94482 "invalid i387 regnum %d") at /home/smarchi/src/binutils-gdb/gdbsupport/errors.cc:55
#9 0x0000563123047d0d in i387_collect_xsave (regcache=0x5631269453f0, regnum=152, xsave=0x7ffd38402a20, gcore=0) at /home/smarchi/src/binutils-gdb/gdb/i387-tdep.c:1408
#10 0x0000563122c69e8a in amd64_collect_xsave (regcache=0x5631269453f0, regnum=152, xsave=0x7ffd38402a20, gcore=0) at /home/smarchi/src/binutils-gdb/gdb/amd64-tdep.c:3448
#11 0x0000563122c5e94c in amd64_linux_nat_target::store_registers (this=0x56312515fd10 <the_amd64_linux_nat_target>, regcache=0x5631269453f0, regnum=152) at /home/smarchi/src/binutils-gdb/gdb/amd64-linux-nat.c:335
#12 0x00005631234c8c80 in target_store_registers (regcache=0x5631269453f0, regno=152) at /home/smarchi/src/binutils-gdb/gdb/target.c:3485
#13 0x00005631232e8df7 in regcache::raw_write (this=0x5631269453f0, regnum=152, buf=0x56312759e468 "@\225\372\367\377\177") at /home/smarchi/src/binutils-gdb/gdb/regcache.c:765
#14 0x00005631232e8f0c in regcache::cooked_write (this=0x5631269453f0, regnum=152, buf=0x56312759e468 "@\225\372\367\377\177") at /home/smarchi/src/binutils-gdb/gdb/regcache.c:778
#15 0x00005631232e75ec in regcache::restore (this=0x5631269453f0, src=0x5631275eb130) at /home/smarchi/src/binutils-gdb/gdb/regcache.c:283
#16 0x0000563123083fc4 in infcall_suspend_state::restore (this=0x5631273ed930, gdbarch=0x56312718cf20, tp=0x5631270bca90, regcache=0x5631269453f0) at /home/smarchi/src/binutils-gdb/gdb/infrun.c:9103
#17 0x0000563123081eed in restore_infcall_suspend_state (inf_state=0x5631273ed930) at /home/smarchi/src/binutils-gdb/gdb/infrun.c:9151
The problem seems to be that amd64_linux_nat_target::store_registers
calls amd64_native_gregset_supplies_p to know whether gregset provides
fs_base. When !HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE,
amd64_native_gregset_supplies_p returns false. store_registers
therefore assumes that it must be an "xstate" register. This is of
course wrong, and that leads to the failed assertion when
i387_collect_xsave doesn't recognize the register.
amd64_linux_nat_target::store_registers could probably be fixed to
handle this case, but I don't think it's worth it, given that it would
only be to support very old kernels.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=df5d438e33d7fc914ba9b6e0d6b019a8966c5fcc
[2] https://sourceware.org/git/?p=glibc.git;a=commit;h=c9cf6ddeebb7bb
[3] https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/?id=88e4bc32686ebd0b1111a94f93eba2d334241f68
gdb/ChangeLog:
* configure.ac: Remove check for fs_base/gs_base in
user_regs_struct.
* configure: Re-generate.
* config.in: Re-generate.
* amd64-nat.c (amd64_native_gregset_reg_offset): Adjust.
* amd64-linux-nat.c (amd64_linux_nat_target::fetch_registers,
amd64_linux_nat_target::store_registers, ps_get_thread_area, ): Adjust.
gdbserver/ChangeLog:
* configure.ac: Remove check for fs_base/gs_base in
user_regs_struct.
* configure: Re-generate.
* config.in: Re-generate.
* linux-x86-low.cc (x86_64_regmap, x86_fill_gregset,
x86_store_gregset): Adjust.
This expands the Python dynamic type documentation, as suggested by
Christian.
gdb/doc/ChangeLog
2020-04-27 Tom Tromey <tromey@adacore.com>
* python.texi (Types In Python): Mention missing fields. Add
dynamic type example.
In PR 25731 [1], the following build failure was reported:
../../binutils-gdb/gdb/gdbtypes.c:1254:10: error: no member named 'abs' in namespace 'std'; did you mean simply 'abs'?
= ((std::abs (stride) * element_count) + 7) / 8;
^~~~~~~~
abs
/usr/include/stdlib.h:129:6: note: 'abs' declared here
int abs(int) __pure2;
^
The original report was using:
$ gcc -v
Apple LLVM version 8.0.0 (clang-800.0.42.1)
Target: x86_64-apple-darwin15.6.0
Note that I was _not_ able to reproduce using:
$ g++ --version
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/4.2.1
Apple clang version 11.0.0 (clang-1100.0.33.17)
Target: x86_64-apple-darwin19.3.0
The proposed fix is to include <cstdlib> in addition to <stdlib.h>.
Here's an excerpt of [2] relevant to this problem:
These headers [speaking of the .h form] are allowed to also declare
the same names in the std namespace, and the corresponding cxxx
headers are allowed to also declare the same names in the global
namespace: including <cstdlib> definitely provides std::malloc and
may also provide ::malloc. Including <stdlib.h> definitely provides
::malloc and may also provide std::malloc
Since we use std::abs, we should not assume that our include of stdlib.h
declares an `abs` function in the `std` namespace.
If we replace the include of stdlib.h with cstdlib, then we fall in the
opposite situation. A standard C++ library may decide to only put the
declarations in the std namespace, requiring us to prefix all standard
functions with `std::`. I'm not against that, but for the moment I think the
safest way forward is to just include both.
Note that I don't know what effect this patch can have on any stdlib.h fix
provided by gnulib.
[1] https://sourceware.org/bugzilla/show_bug.cgi?id=25731
[2] https://en.cppreference.com/w/cpp/header#C_compatibility_headers
gdbsupport/ChangeLog:
* common-defs.h: Include cstdlib.h.
Commit 5939967b35 fixed inline
frame unwinding breakage for some targets (aarch64, riscv, s390...)
but regressed a few amd64 testcases related to tailcalls.
Given the following example situation...
Frame #-1 - sentinel frame
Frame # 0 - inline frame
Frame # 1 - normal frame
... suppose we're at level #1 and call into dwarf2_tailcall_sniffer_first.
We'll attempt to fetch PC, which used to be done via the gdbarch_unwind_pc call
(before 5939967b35), but now it is being handled
by the get_frame_register function.
gdbarch_unwind_pc will attempt to use frame #1's cache to retrieve information
about the PC. Here's where different architectures behave differently.
x86_64 will find a dwarf rule to retrieve PC from memory, at a CFA + offset
location. So the PC value is readily available and there is no need to
create a lazy value.
For aarch64 (and others), GCC doesn't emit an explicit location for PC, so we
eventually will find that PC is DWARF2_FRAME_REG_UNSPECIFIED. This is known
and is handled by GDB by assuming GCC really meant DWARF2_FRAME_REG_SAME_VALUE.
This means we'll attempt to fetch the register value from frame #0, via a call
to frame_unwind_got_register, which will trigger the creation of a lazy value
that requires a valid frame id for frame #0.
We don't have a valid id for frame #0 yet, so we assert.
Given the above, the following patch attempts to handle the situation without
being too hacky. We verify if the next frame is an inline frame and if its
frame id has been computed already. If it hasn't been computed yet, then we
use the safer get_frame_register function, otherwise we use the regular
gdbarch_unwind_pc hook.
gdb/ChangeLog:
2020-04-27 Luis Machado <luis.machado@linaro.org>
* dwarf2/frame-tailcall.c (dwarf2_tailcall_sniffer_first): Handle
problematic inline frame unwinding situation.
* frame.c (frame_id_computed_p): New function.
* frame.h (frame_id_computed_p): New prototype.
PR 25878
* dwarf2dbg.c (struct file_entry): Add auto_assigned field.
(assign_file_to_slot): New function. Fills in an entry in the
files table.
(allocate_filenum): Use new function.
(allocate_filename_to_slot): Use new function. If the specified
slot entry is already in use, but was chosen automatically then
reassign the automatic entry.
The class_pseudo constant is unused, so this removes it.
Tested by rebuilding.
gdb/ChangeLog
2020-04-26 Tom Tromey <tom@tromey.com>
* command.h (enum command_class) <class_pseudo>: Remove.
This fixes another missing error check.
* readelf.c (get_num_dynamic_syms): Check DT_MIPS_XHASH was
read before dereferencing, and gracefully return. Remove
gnu_hash_error variable. Free gnu hash arrays if number of
syms found is zero.
Simon Marchi
Sterling Augustine
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