This rewrites gdb's TRY/CATCH to plain C++ try/catch. The patch was
largely written by script, though one change (to a comment in
common-exceptions.h) was reverted by hand.
gdb/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* xml-support.c: Use C++ exception handling.
* x86-linux-nat.c: Use C++ exception handling.
* windows-nat.c: Use C++ exception handling.
* varobj.c: Use C++ exception handling.
* value.c: Use C++ exception handling.
* valprint.c: Use C++ exception handling.
* valops.c: Use C++ exception handling.
* unittests/parse-connection-spec-selftests.c: Use C++ exception
handling.
* unittests/cli-utils-selftests.c: Use C++ exception handling.
* typeprint.c: Use C++ exception handling.
* tui/tui.c: Use C++ exception handling.
* tracefile-tfile.c: Use C++ exception handling.
* top.c: Use C++ exception handling.
* thread.c: Use C++ exception handling.
* target.c: Use C++ exception handling.
* symmisc.c: Use C++ exception handling.
* symfile-mem.c: Use C++ exception handling.
* stack.c: Use C++ exception handling.
* sparc64-linux-tdep.c: Use C++ exception handling.
* solib.c: Use C++ exception handling.
* solib-svr4.c: Use C++ exception handling.
* solib-spu.c: Use C++ exception handling.
* solib-frv.c: Use C++ exception handling.
* solib-dsbt.c: Use C++ exception handling.
* selftest-arch.c: Use C++ exception handling.
* s390-tdep.c: Use C++ exception handling.
* rust-lang.c: Use C++ exception handling.
* rust-exp.y: Use C++ exception handling.
* rs6000-tdep.c: Use C++ exception handling.
* rs6000-aix-tdep.c: Use C++ exception handling.
* riscv-tdep.c: Use C++ exception handling.
* remote.c: Use C++ exception handling.
* remote-fileio.c: Use C++ exception handling.
* record-full.c: Use C++ exception handling.
* record-btrace.c: Use C++ exception handling.
* python/python.c: Use C++ exception handling.
* python/py-value.c: Use C++ exception handling.
* python/py-utils.c: Use C++ exception handling.
* python/py-unwind.c: Use C++ exception handling.
* python/py-type.c: Use C++ exception handling.
* python/py-symbol.c: Use C++ exception handling.
* python/py-record.c: Use C++ exception handling.
* python/py-record-btrace.c: Use C++ exception handling.
* python/py-progspace.c: Use C++ exception handling.
* python/py-prettyprint.c: Use C++ exception handling.
* python/py-param.c: Use C++ exception handling.
* python/py-objfile.c: Use C++ exception handling.
* python/py-linetable.c: Use C++ exception handling.
* python/py-lazy-string.c: Use C++ exception handling.
* python/py-infthread.c: Use C++ exception handling.
* python/py-inferior.c: Use C++ exception handling.
* python/py-gdb-readline.c: Use C++ exception handling.
* python/py-framefilter.c: Use C++ exception handling.
* python/py-frame.c: Use C++ exception handling.
* python/py-finishbreakpoint.c: Use C++ exception handling.
* python/py-cmd.c: Use C++ exception handling.
* python/py-breakpoint.c: Use C++ exception handling.
* python/py-arch.c: Use C++ exception handling.
* printcmd.c: Use C++ exception handling.
* ppc-linux-tdep.c: Use C++ exception handling.
* parse.c: Use C++ exception handling.
* p-valprint.c: Use C++ exception handling.
* objc-lang.c: Use C++ exception handling.
* mi/mi-main.c: Use C++ exception handling.
* mi/mi-interp.c: Use C++ exception handling.
* mi/mi-cmd-stack.c: Use C++ exception handling.
* mi/mi-cmd-break.c: Use C++ exception handling.
* main.c: Use C++ exception handling.
* linux-thread-db.c: Use C++ exception handling.
* linux-tdep.c: Use C++ exception handling.
* linux-nat.c: Use C++ exception handling.
* linux-fork.c: Use C++ exception handling.
* linespec.c: Use C++ exception handling.
* language.c: Use C++ exception handling.
* jit.c: Use C++ exception handling.
* infrun.c: Use C++ exception handling.
* infcmd.c: Use C++ exception handling.
* infcall.c: Use C++ exception handling.
* inf-loop.c: Use C++ exception handling.
* i386-tdep.c: Use C++ exception handling.
* i386-linux-tdep.c: Use C++ exception handling.
* guile/scm-value.c: Use C++ exception handling.
* guile/scm-type.c: Use C++ exception handling.
* guile/scm-symtab.c: Use C++ exception handling.
* guile/scm-symbol.c: Use C++ exception handling.
* guile/scm-pretty-print.c: Use C++ exception handling.
* guile/scm-ports.c: Use C++ exception handling.
* guile/scm-param.c: Use C++ exception handling.
* guile/scm-math.c: Use C++ exception handling.
* guile/scm-lazy-string.c: Use C++ exception handling.
* guile/scm-frame.c: Use C++ exception handling.
* guile/scm-disasm.c: Use C++ exception handling.
* guile/scm-cmd.c: Use C++ exception handling.
* guile/scm-breakpoint.c: Use C++ exception handling.
* guile/scm-block.c: Use C++ exception handling.
* guile/guile-internal.h: Use C++ exception handling.
* gnu-v3-abi.c: Use C++ exception handling.
* gdbtypes.c: Use C++ exception handling.
* frame.c: Use C++ exception handling.
* frame-unwind.c: Use C++ exception handling.
* fbsd-tdep.c: Use C++ exception handling.
* f-valprint.c: Use C++ exception handling.
* exec.c: Use C++ exception handling.
* event-top.c: Use C++ exception handling.
* event-loop.c: Use C++ exception handling.
* eval.c: Use C++ exception handling.
* dwarf2read.c: Use C++ exception handling.
* dwarf2loc.c: Use C++ exception handling.
* dwarf2-frame.c: Use C++ exception handling.
* dwarf2-frame-tailcall.c: Use C++ exception handling.
* dwarf-index-write.c: Use C++ exception handling.
* dwarf-index-cache.c: Use C++ exception handling.
* dtrace-probe.c: Use C++ exception handling.
* disasm-selftests.c: Use C++ exception handling.
* darwin-nat.c: Use C++ exception handling.
* cp-valprint.c: Use C++ exception handling.
* cp-support.c: Use C++ exception handling.
* cp-abi.c: Use C++ exception handling.
* corelow.c: Use C++ exception handling.
* completer.c: Use C++ exception handling.
* compile/compile-object-run.c: Use C++ exception handling.
* compile/compile-object-load.c: Use C++ exception handling.
* compile/compile-cplus-symbols.c: Use C++ exception handling.
* compile/compile-c-symbols.c: Use C++ exception handling.
* common/selftest.c: Use C++ exception handling.
* common/new-op.c: Use C++ exception handling.
* cli/cli-script.c: Use C++ exception handling.
* cli/cli-interp.c: Use C++ exception handling.
* cli/cli-cmds.c: Use C++ exception handling.
* c-varobj.c: Use C++ exception handling.
* btrace.c: Use C++ exception handling.
* breakpoint.c: Use C++ exception handling.
* break-catch-throw.c: Use C++ exception handling.
* arch-utils.c: Use C++ exception handling.
* amd64-tdep.c: Use C++ exception handling.
* ada-valprint.c: Use C++ exception handling.
* ada-typeprint.c: Use C++ exception handling.
* ada-lang.c: Use C++ exception handling.
* aarch64-tdep.c: Use C++ exception handling.
gdb/gdbserver/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* server.c: Use C++ exception handling.
* linux-low.c: Use C++ exception handling.
* gdbreplay.c: Use C++ exception handling.
This commit restructures the relationship between the type_align
function and the gdbarch_type_align method.
The problem being addressed with this commit is this; previously the
type_align function was structured so that for "basic" types (int,
float, etc) the gdbarch_type_align hook was called, which for
"compound" types (arrays, structs, etc) the common type_align code has
a fixed method for how to extract a "basic" type and would then call
itself on that "basic" type.
The problem is that if an architecture wants to modify the alignment
rules for a "compound" type then this is not currently possible.
In the revised structure, all types pass through the
gdbarch_type_align method. If this method returns 0 then this
indicates that the architecture has no special rules for this type,
and GDB should apply the default rules for alignment. However, the
architecture is free to provide an alignment for any type, both
"basic" and "compound".
After this commit the default alignment rules now all live in the
type_align function, the default_type_align only ever returns 0,
meaning apply the default rules.
I've updated the 3 targets (arc, i386, and nios2) that already
override the gdbarch_type_align method to fit the new scheme.
Tested on X86-64/GNU Linux with no regressions.
gdb/ChangeLog:
* arc-tdep.c (arc_type_align): Provide alignment for basic types,
return 0 for other types.
* arch-utils.c (default_type_align): Always return 0.
* gdbarch.h: Regenerate.
* gdbarch.sh (type_align): Extend comment.
* gdbtypes.c (type_align): Add additional comments, always call
gdbarch_type_align before applying the default rules.
* i386-tdep.c (i386_type_align): Return 0 as the default rule,
generic code will then apply a suitable default.
* nios2-tdep.c (nios2_type_align): Provide alignment for basic
types, return 0 for other types.
This commit applies all changes made after running the gdb/copyright.py
script.
Note that one file was flagged by the script, due to an invalid
copyright header
(gdb/unittests/basic_string_view/element_access/char/empty.cc).
As the file was copied from GCC's libstdc++-v3 testsuite, this commit
leaves this file untouched for the time being; a patch to fix the header
was sent to gcc-patches first.
gdb/ChangeLog:
Update copyright year range in all GDB files.
A few files no longer need to include buildsym.h.
gdb/ChangeLog
2018-07-20 Tom Tromey <tom@tromey.com>
* arch-utils.c: Do not include buildsym.h.
* mipsread.c: Do not include buildsym.h.
* machoread.c: Do not include buildsym.h.
* elfread.c: Do not include buildsym.h.
The type alignment value is returned in 8-bit-bytes instead of target
memory addressable units. For example, on a target with 16-bit-bytes
where sizeof(int) == 1 (one addressable unit), alignof(int) currently
returns 2. After, this patch, it returns 1.
gdb/ChangeLog:
* arch-utils.c (default_type_align): Use type_length_units.
* gdbtypes.c (type_align): Use type_length_units.
Use the last endianness explicitly selected, either by choosing a binary
file or with the `set endian' command, for future automatic selection.
As observed with the `gdb.base/step-over-no-symbols.exp' test case when
discarding the binary file even while connected to a live target the
endianness automatically selected is reset to the GDB target's default,
even if it does not match the endianness of the target being talked to.
For example with a little-endian MIPS target and the default endianness
being big we get this:
(gdb) file .../gdb/testsuite/outputs/gdb.base/step-over-no-symbols/step-over-no-symbols
Reading symbols from .../gdb/testsuite/outputs/gdb.base/step-over-no-symbols/step-over-no-symbols...done.
(gdb) delete breakpoints
(gdb) info breakpoints
No breakpoints or watchpoints.
(gdb) break main
Breakpoint 1 at 0x400840: file .../gdb/testsuite/gdb.base/start.c, line 34.
[...]
(gdb) continue
Continuing.
Breakpoint 1, main () at .../gdb/testsuite/gdb.base/start.c:34
34 foo();
(gdb) delete breakpoints
Delete all breakpoints? (y or n) y
(gdb) info breakpoints
No breakpoints or watchpoints.
(gdb) file
A program is being debugged already.
Are you sure you want to change the file? (y or n) y
No executable file now.
Discard symbol table from `.../gdb/testsuite/outputs/gdb.base/step-over-no-symbols/step-over-no-symbols'? (y or n) y
No symbol file now.
(gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=off: purging symbols
p /x $pc
$1 = 0x40084000
(gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=off: get before PC
break *$pc
Breakpoint 2 at 0x40084000
(gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=off: break *$pc
set displaced-stepping off
(gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=off: set displaced-stepping off
stepi
Warning:
Cannot insert breakpoint 2.
Cannot access memory at address 0x40084000
Command aborted.
(gdb) FAIL: gdb.base/step-over-no-symbols.exp: displaced=off: stepi
p /x $pc
$2 = 0x40084000
(gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=off: get after PC
FAIL: gdb.base/step-over-no-symbols.exp: displaced=off: advanced
Remote debugging from host ...
monitor exit
(gdb) Killing process(es): ...
testcase .../gdb/testsuite/gdb.base/step-over-no-symbols.exp completed in 2 seconds
which shows that with the removal of the executable debugged the
endianness of $pc still at `main' gets swapped and the value in that
register is now incorrectly interpreted as 0x40084000 rather than
0x400840 as shown earlier on with the `break' command. Consequently the
debug session no longer works as expected, until the endianness is
overridden with an explicit `set endian little' command.
This will happen while working with any target hardware whose endianness
does not match the default GDB target's endianness guessed and recorded
for a later use in `initialize_current_architecture'.
Given that within a single run of GDB it is more likely that consecutive
target connections will use the same endianness than that the endianness
will be swapped between connections, it makes sense to preserve the last
endianness explicitly selected as the automatic default. It will make a
session like above, where an executable is removed, work correctly and
will retain the endianness for a further reconnection to the target.
And the new automatic default will still be overridden by subsequently
choosing a binary to debug, or with an explicit `set endian' command.
With the change in place the test case above completes successfully:
(gdb) continue
Continuing.
Breakpoint 1, main () at .../gdb/testsuite/gdb.base/start.c:34
34 foo();
(gdb) delete breakpoints
Delete all breakpoints? (y or n) y
(gdb) info breakpoints
No breakpoints or watchpoints.
(gdb) file
A program is being debugged already.
Are you sure you want to change the file? (y or n) y
No executable file now.
Discard symbol table from `.../gdb/testsuite/outputs/gdb.base/step-over-no-symbols/step-over-no-symbols'? (y or n) y
No symbol file now.
(gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=off: purging symbols
p /x $pc
warning: GDB can't find the start of the function at 0x400840.
GDB is unable to find the start of the function at 0x400840
and thus can't determine the size of that function's stack frame.
This means that GDB may be unable to access that stack frame, or
the frames below it.
This problem is most likely caused by an invalid program counter or
stack pointer.
However, if you think GDB should simply search farther back
from 0x400840 for code which looks like the beginning of a
function, you can increase the range of the search using the `set
heuristic-fence-post' command.
$1 = 0x400840
(gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=off: get before PC
break *$pc
Breakpoint 2 at 0x400840
(gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=off: break *$pc
set displaced-stepping off
(gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=off: set displaced-stepping off
stepi
warning: GDB can't find the start of the function at 0x4007f8.
0x004007f8 in ?? ()
(gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=off: stepi
p /x $pc
$2 = 0x4007f8
(gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=off: get after PC
PASS: gdb.base/step-over-no-symbols.exp: displaced=off: advanced
Remote debugging from host ...
monitor exit
(gdb) Killing process(es): ...
testcase .../gdb/testsuite/gdb.base/step-over-no-symbols.exp completed in 2 seconds
gdb/
* arch-utils.c (gdbarch_info_fill): Set `default_byte_order' to
the endianness selected.
* NEWS: Document `set endian auto' mode operation update.
gdb/doc/
* gdb.texinfo (Choosing Target Byte Order): Document endianness
selection details with the `set endian auto' mode.
gdb/testsuite
* gdb.base/endian.exp: New test.
* gdb.base/endian.c: New test source.
This adds some basic type alignment support to gdb. It changes struct
type to store the alignment, and updates dwarf2read.c to handle
DW_AT_alignment. It also adds a new gdbarch method and updates
i386-tdep.c.
None of this new functionality is used anywhere yet, so tests will
wait until the next patch.
2018-04-30 Tom Tromey <tom@tromey.com>
* i386-tdep.c (i386_type_align): New function.
(i386_gdbarch_init): Update.
* gdbarch.sh (type_align): New method.
* gdbarch.c, gdbarch.h: Rebuild.
* arch-utils.h (default_type_align): Declare.
* arch-utils.c (default_type_align): New function.
* gdbtypes.h (TYPE_ALIGN_BITS): New define.
(struct type) <align_log2>: New field.
<instance_flags>: Now a bitfield.
(TYPE_RAW_ALIGN): New macro.
(type_align, type_raw_align, set_type_align): Declare.
* gdbtypes.c (type_align, type_raw_align, set_type_align): New
functions.
* dwarf2read.c (quirk_rust_enum): Set type alignment.
(get_alignment, maybe_set_alignment): New functions.
(read_structure_type, read_enumeration_type, read_array_type)
(read_set_type, read_tag_pointer_type, read_tag_reference_type)
(read_subrange_type, read_base_type): Set type alignment.
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.
I was looking for a way to reproduce easily PR 22979 by doing this:
(gdb) set architecture i386:x86-64
(gdb) set osabi none
However, I noticed that even though I did "set osabi none", the gdbarch
gdb created was for Linux:
(gdb) set debug arch 1
(gdb) set architecture i386:x86-64
...
(gdb) set osabi none
gdbarch_find_by_info: info.bfd_arch_info i386:x86-64
gdbarch_find_by_info: info.byte_order 1 (little)
gdbarch_find_by_info: info.osabi 4 (GNU/Linux) <--- Wrong?
gdbarch_find_by_info: info.abfd 0x0
gdbarch_find_by_info: info.tdep_info 0x0
gdbarch_find_by_info: Previous architecture 0x1e6fd30 (i386:x86-64)
selected
gdbarch_update_p: Architecture 0x1e6fd30 (i386:x86-64) unchanged
This is because the value GDB_OSABI_UNKNOWN has an unclear role,
sometimes meaning "no osabi" and sometimes "please selected
automatically". Doing "set osabi none" sets the requested osabi to
GDB_OSABI_UNKNOWN, in which case gdbarch_info_fill overrides it with a
value from the target description, or the built-in default osabi. This
means that it's impossible to force GDB not to use an osabi with "set
osabi". Since my GDB's built-in default osabi is Linux, it always falls
back to GDB_OSABI_LINUX.
To fix it, I introduced GDB_OSABI_NONE, which really means "I don't want
any osabi". GDB_OSABI_UNKNOWN can then be used only for "not set yet,
please auto-detect". GDB_OSABI_UNINITIALIZED now seems unnecessary
since it overlaps with GDB_OSABI_UNKNOWN, so I think it can be removed
and gdbarch_info::osabi can be initialized to GDB_OSABI_UNKNOWN.
gdb/ChangeLog:
PR gdb/22980
* defs.h (enum gdb_osabi): Remove GDB_OSABI_UNINITIALIZED, add
GDB_OSABI_NONE.
* arch-utils.c (gdbarch_info_init): Don't set info->osabi.
* osabi.c (gdb_osabi_names): Add "unknown" entry.
gdb/testsuite/ChangeLog:
PR gdb/22980
* gdb.base/osabi.exp: New file.
This changes the gdbarch fast_tracepoint_valid_at method to use a
std::string as its out parameter, and then updates all the uses. This
allows removing a cleanup from breakpoint.c.
Regression tested by the buildbot.
ChangeLog
2018-02-24 Tom Tromey <tom@tromey.com>
* i386-tdep.c (i386_fast_tracepoint_valid_at): "msg" now a
std::string.
* gdbarch.sh (fast_tracepoint_valid_at): Change "msg" to a
std::string*.
* gdbarch.c: Rebuild.
* gdbarch.h: Rebuild.
* breakpoint.c (check_fast_tracepoint_sals): Use std::string.
* arch-utils.h (default_fast_tracepoint_valid_at): Update.
* arch-utils.c (default_fast_tracepoint_valid_at): "msg" now a
std::string*.
Fix `set architecture' and `set endian' command disassembly regressions
from commit 39503f8242 ("Delegate opcodes to select disassembler in
GDB"), and commit 003ca0fd22 ("Refactor disassembler selection"), as
well as a MIPS compressed ISA disassembly target regression from commit
6394c60699 ("Don't use print_insn_XXX in GDB"), which caused assertion
failures to trigger.
For example with the `mips-linux-gnu' target we get:
$ cat main.c
int
main (void)
{
return 0;
}
$ gcc -mips32r2 -O2 main.c -o main
$ gcc -mips16 -mips32r2 -O2 main.c -o main16
$ gdb
GNU gdb (GDB) 8.0.50.20170731-git
[...]
(gdb) file main
Reading symbols from main...done.
(gdb) show architecture
The target architecture is set automatically (currently mips:isa32r2)
(gdb) show endian
The target endianness is set automatically (currently big endian)
(gdb) disassemble main
Dump of assembler code for function main:
0x00400500 <+0>: jr ra
0x00400504 <+4>: move v0,zero
End of assembler dump.
(gdb) set architecture mips:isa64r2
The target architecture is assumed to be mips:isa64r2
(gdb) disassemble main
Dump of assembler code for function main:
0x00400500 <+0>:
.../gdb/arch-utils.c:979: internal-error: int default_print_insn(bfd_vma, disassemble_info*): Assertion `info->mach == bfd_get_mach (exec_bfd)' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) n
[...]
Command aborted.
(gdb) set architecture auto
The target architecture is set automatically (currently mips:isa32r2)
(gdb) set endian little
The target is assumed to be little endian
(gdb) disassemble main
Dump of assembler code for function main:
0x00400500 <+0>:
.../gdb/arch-utils.c:978: internal-error: int default_print_insn(bfd_vma, disassemble_info*): Assertion `info->endian == (bfd_big_endian (exec_bfd) ? BFD_ENDIAN_BIG : BFD_ENDIAN_LITTLE)' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) n
[...]
Command aborted.
(gdb) set endian auto
The target endianness is set automatically (currently big endian)
(gdb) set architecture i386
The target architecture is assumed to be i386
(gdb) disassemble main
Dump of assembler code for function main:
0x00400500 <+0>:
.../gdb/arch-utils.c:976: internal-error: int default_print_insn(bfd_vma, disassemble_info*): Assertion `info->arch == bfd_get_arch (exec_bfd)' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) n
[...]
Command aborted.
(gdb) set architecture auto
The target architecture is set automatically (currently mips:isa32r2)
(gdb) file main16
Load new symbol table from "main16"? (y or n) y
Reading symbols from main16...done.
(gdb) disassemble main
Dump of assembler code for function main:
0x00400501 <+0>:
.../gdb/arch-utils.c:979: internal-error: int default_print_insn(bfd_vma, disassemble_info*): Assertion `info->mach == bfd_get_mach (exec_bfd)' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) n
Command aborted.
(gdb)
Remove the assertions then, restoring previous semantics:
(gdb) file main
Reading symbols from main...done.
(gdb) set architecture mips:isa64r2
The target architecture is assumed to be mips:isa64r2
(gdb) disassemble main
Dump of assembler code for function main:
0x00400500 <+0>: jr ra
0x00400504 <+4>: move v0,zero
End of assembler dump.
(gdb) set endian little
The target is assumed to be little endian
(gdb) disassemble main
Dump of assembler code for function main:
0x00400500 <+0>: j 0x3800c
0x00400504 <+4>: addiu s0,t0,0
End of assembler dump.
(gdb) set architecture i386
The target architecture is assumed to be i386
(gdb) disassemble main
Dump of assembler code for function main:
0x00400500 <+0>: add %eax,%esp
0x00400502 <+2>: add %cl,(%eax)
0x00400504 <+4>: add %al,(%eax)
0x00400506 <+6>: adc %ah,0x0
End of assembler dump.
(gdb) set architecture auto
The target architecture is set automatically (currently mips:isa32r2)
(gdb) set endian auto
The target endianness is set automatically (currently big endian)
(gdb) file main16
Load new symbol table from "main16"? (y or n) y
Reading symbols from main16...done.
(gdb) disassemble main
Dump of assembler code for function main:
0x00400501 <+0>: jr ra
0x00400503 <+2>: li v0,0
End of assembler dump.
(gdb)
gdb/
* arch-utils.c (default_print_insn): Remove arch/mach/endian
assertions.
opcodes/
* disassemble.c (disassembler): Remove arch/mach/endian
assertions.
PR 21555 is caused by the exception during the prologue analysis when re-set
a breakpoint.
(gdb) bt
#0 memory_error_message (err=TARGET_XFER_E_IO, gdbarch=0x153db50, memaddr=93824992233232) at ../../binutils-gdb/gdb/corefile.c:192
#1 0x00000000005718ed in memory_error (err=TARGET_XFER_E_IO, memaddr=memaddr@entry=93824992233232) at ../../binutils-gdb/gdb/corefile.c:220
#2 0x00000000005719d6 in read_memory_object (object=object@entry=TARGET_OBJECT_CODE_MEMORY, memaddr=93824992233232, memaddr@entry=1, myaddr=myaddr@entry=0x7fffffffd0a0 "P\333S\001", len=len@entry=1) at ../../binutils-gdb/gdb/corefile.c:259
#3 0x0000000000571c6e in read_code (len=1, myaddr=0x7fffffffd0a0 "P\333S\001", memaddr=<optimized out>) at ../../binutils-gdb/gdb/corefile.c:287
#4 read_code_unsigned_integer (memaddr=memaddr@entry=93824992233232, len=len@entry=1, byte_order=byte_order@entry=BFD_ENDIAN_LITTLE) at ../../binutils-gdb/gdb/corefile.c:362
#5 0x000000000041d4a0 in amd64_analyze_prologue (gdbarch=gdbarch@entry=0x153db50, pc=pc@entry=93824992233232, current_pc=current_pc@entry=18446744073709551615, cache=cache@entry=0x7fffffffd1e0) at ../../binutils-gdb/gdb/amd64-tdep.c:2310
#6 0x000000000041e404 in amd64_skip_prologue (gdbarch=0x153db50, start_pc=93824992233232) at ../../binutils-gdb/gdb/amd64-tdep.c:2459
#7 0x000000000067bfb0 in skip_prologue_sal (sal=sal@entry=0x7fffffffd4e0) at ../../binutils-gdb/gdb/symtab.c:3628
#8 0x000000000067c4d8 in find_function_start_sal (sym=sym@entry=0x1549960, funfirstline=1) at ../../binutils-gdb/gdb/symtab.c:3501
#9 0x000000000060999d in symbol_to_sal (result=result@entry=0x7fffffffd5f0, funfirstline=<optimized out>, sym=sym@entry=0x1549960) at ../../binutils-gdb/gdb/linespec.c:3860
....
#16 0x000000000054b733 in location_to_sals (b=b@entry=0x15792d0, location=0x157c230, search_pspace=search_pspace@entry=0x1148120, found=found@entry=0x7fffffffdc64) at ../../binutils-gdb/gdb/breakpoint.c:14211
#17 0x000000000054c1f5 in breakpoint_re_set_default (b=0x15792d0) at ../../binutils-gdb/gdb/breakpoint.c:14301
#18 0x00000000005412a9 in breakpoint_re_set_one (bint=bint@entry=0x15792d0) at ../../binutils-gdb/gdb/breakpoint.c:14412
This problem can be fixed by
- either each prologue analyzer doesn't throw exception,
- or catch the exception thrown from gdbarch_skip_prologue,
I choose the latter because the former needs to fix *every* prologue
analyzer to not throw exception.
This error can be reproduced by changing reread.exp. The test reread.exp
has already test that breakpoint can be reset correctly after the
executable is re-read. This patch extends this test by compiling test c
file with and without -fPIE.
(gdb) run ^M
The program being debugged has been started already.^M
Start it from the beginning? (y or n) y^M
x86_64/gdb/testsuite/outputs/gdb.base/reread/reread' has changed; re-reading symbols.
Error in re-setting breakpoint 1: Cannot access memory at address 0x555555554790^M
Error in re-setting breakpoint 2: Cannot access memory at address 0x555555554790^M
Starting program: /scratch/yao/gdb/build-git/x86_64/gdb/testsuite/outputs/gdb.base/reread/reread ^M
This is foo^M
[Inferior 1 (process 27720) exited normally]^M
(gdb) FAIL: gdb.base/reread.exp: opts= "-fPIE" "ldflags=-pie" : run to foo() second time (the program exited)
This patch doesn't re-indent the code, to keep the patch simple.
gdb:
2017-07-25 Yao Qi <yao.qi@linaro.org>
PR gdb/21555
* arch-utils.c (gdbarch_skip_prologue_noexcept): New function.
* arch-utils.h (gdbarch_skip_prologue_noexcept): Declare.
* infrun.c: Include arch-utils.h
(handle_step_into_function): Call gdbarch_skip_prologue_noexcept.
(handle_step_into_function_backward): Likewise.
* symtab.c (skip_prologue_sal): Likewise.
gdb/testsuite:
2017-07-25 Yao Qi <yao.qi@linaro.org>
PR gdb/21555
* gdb.base/reread.exp: Wrap the whole test with two kinds of
compilation flags, with -fPIE and without -fPIE.
The displaced_step_free_closure gdbarch hook allows architectures to
free data they might have allocated to complete a displaced step.
However, all architectures using that hook use the
simple_displaced_step_free_closure provided in arch-utils.{c,h}, which
does a simple xfree. We can remove it and do an xfree directly instead
of calling the hook.
gdb/ChangeLog:
* gdbarch.sh (displaced_step_free_closure): Remove.
* gdbarch.h, gdbarch.c: Re-generate.
* aarch64-linux-tdep.c (aarch64_linux_init_abi): Don't set
displaced_step_free_closure.
* amd64-linux-tdep.c (amd64_linux_init_abi_common): Likewise.
* arm-linux-tdep.c (arm_linux_init_abi): Likewise.
* i386-linux-tdep.c (i386_linux_init_abi): Likewise.
* rs6000-aix-tdep.c (rs6000_aix_init_osabi): Likewise.
* rs6000-tdep.c (rs6000_gdbarch_init): Likewise.
* s390-linux-tdep.c (s390_gdbarch_init): Likewise.
* arch-utils.h (simple_displaced_step_free_closure): Remove.
* arch-utils.c (simple_displaced_step_free_closure): Remove.
* infrun.c (displaced_step_clear): Call xfree instead of
gdbarch_displaced_step_free_closure.
Recently a feature called "return address signing" has been added to GCC to
prevent stack smash stack on AArch64. For details please refer:
https://gcc.gnu.org/ml/gcc-patches/2017-01/msg00376.html
GDB needs to be aware of this feature so it can restore the original return
address which is critical for unwinding.
On compiler side, whenever return address, i.e. LR register, is mangled or
restored by hardware instruction, compiler is expected to generate a
DW_CFA_AARCH64_negate_ra_state to toggle return address signing status.
DW_CFA_AARCH64_negate_ra_state is using the same CFI number and
therefore need to be multiplexed with DW_CFA_GNU_window_save which was designed
for SPARC.
A new gdbarch method "execute_dwarf_cfa_vendor_op" is introduced by this patch.
It's parameters has been restricted to those only needed by SPARC and AArch64
for multiplexing DW_CFA_GNU_window_save which is a CFI operation takes none
operand. Should any further DWARF CFI operation want to be multiplexed in the
future, the parameter list can be extended. Below is the current function
prototype.
typedef int (gdbarch_execute_dwarf_cfa_vendor_op_ftype)
(struct gdbarch *gdbarch, gdb_byte op, struct dwarf2_frame_state *fs);
DW_CFA_GNU_window_save support for SPARC is migrated to this new gdbarch
method by this patch.
gdb/
* gdbarch.sh: New gdbarch method execute_dwarf_cfa_vendor_op.
* gdbarch.c: Regenerated.
* gdbarch.h: Regenerated.
* dwarf2-frame.c (dwarf2_frame_state_alloc_regs): Made the
visibility external.
(execute_cfa_program): Call execute_dwarf_cfa_vendor_op for CFI
between DW_CFA_lo_user and DW_CFA_high_user inclusive.
(enum cfa_how_kind): Move to ...
(struct dwarf2_frame_state_reg_info): Likewise.
(struct dwarf2_frame_state): Likewise.
* dwarf2-frame.h: ... here.
(dwarf2_frame_state_alloc_regs): New declaration.
* sparc-tdep.c (sparc_execute_dwarf_cfa_vendor_op): New function.
(sparc32_gdbarch_init): Register execute_dwarf_cfa_vendor_op hook.
This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.
gdb/ChangeLog:
Update copyright year range in all GDB files.
This patch adds a new gdbarch method breakpoint_kind_from_current_state
for single step breakpoint, and uses it in breakpoint_kind.
gdb:
2016-11-03 Yao Qi <yao.qi@linaro.org>
* arch-utils.c (default_breakpoint_kind_from_current_state):
New function.
* arch-utils.h (default_breakpoint_kind_from_current_state):
Declare.
* arm-tdep.c (arm_breakpoint_kind_from_current_state): New
function.
(arm_gdbarch_init): Call
set_gdbarch_breakpoint_kind_from_current_state.
* breakpoint.c (breakpoint_kind): Call
gdbarch_breakpoint_kind_from_current_state for single step
breakpoint. Update comments.
* gdbarch.sh (breakpoint_kind_from_current_state): New.
* gdbarch.c, gdbarch.h: Regenerate.
At this point, all TYPE_CODE_FLT types carry their floating-point format,
except for those creating from reading DWARF or stabs debug info. Those
will be addressed by this commit.
The main issue here is that we actually have to determine which floating-
point format to use. Currently, we only have the type length as input
to this decision. In the future, we may hopefully get --at least in
DWARF-- additional information to help disambiguate multiple different
formats of the same length. For now, we can still look at the type name
as a hint.
This decision logic is encapsulated in a gdbarch callback to allow
platform-specific overrides. The default implementation use the same
logic (compare type length against the various gdbarch_..._bit sizes)
that is currently implemented in floatformat_from_length.
With this commit, all platforms still use the default logic, so there
should be no actual change in behavior. A follow-on commit will add
support for __float128 on Intel and Power.
Once dwarf2read.c and stabsread.c make use of the new callback to
determine floating-point formats, we're now sure every TYPE_CODE_FLT
type will always carry its format. The commit therefore adds asserts
to verify_floatformat to ensure new code will continue to always
provide formats, and removes the code in floatformat_from_type that
used to handle types with a NULL TYPE_FLOATFORMAT.
gdb/ChangeLog:
* gdbarch.sh (floatformat_for_type): New gdbarch callback.
* gdbarch.h, gdbarch.c: Re-generate.
* arch-utils.h (default_floatformat_for_type): New prototype.
* arch-utils.c (default_floatformat_for_type): New function.
* doublest.c (floatformat_from_length): Remove.
(floatformat_from_type): Assume TYPE_FLOATFORMAT is non-NULL.
* gdbtypes.c (verify_floatformat): Require non-NULL format.
* dwarf2read.c (dwarf2_init_float_type): New function.
(read_base_type): Use it.
* stabsread.c (dbx_init_float_type): New function.
(read_sun_floating_type): Use it.
(read_range_type): Likewise.
Signed-off-by: Ulrich Weigand <ulrich.weigand@de.ibm.com>
This patch consolidates the (possibly-questionable) spots where we
remove a declaration but continue to call some function for side
effects. In a couple of cases it wasn't entirely clear to me that
this mattered; and in some other cases it might be more aesthetically
pleasing to use ATTRIBUTE_UNUSED. So, I broke this out into a
separate patch for simpler review.
2016-07-14 Tom Tromey <tom@tromey.com>
* arch-utils.c (default_skip_permanent_breakpoint): Remove
"bp_insn".
* disasm.c (do_assembly_only): Remove "num_displayed".
* dwarf2read.c (read_abbrev_offset): Remove "length".
(dwarf_decode_macro_bytes) <DW_MACINFO_vendor_ext>: Remove
"constant".
* m32c-tdep.c (make_regs): Remove "r2hl", "r3hl", and "intbhl".
* microblaze-tdep.c (microblaze_frame_cache): Remove "func".
* tracefile.c (trace_save): Remove "status".
Nowadays, GDB can't insert breakpoint on the return address of the
exception handler on ARM M-profile, because the address is a magic
one 0xfffffff9,
(gdb) bt
#0 CT32B1_IRQHandler () at ../src/timer.c:67
#1 <signal handler called>
#2 main () at ../src/timer.c:127
(gdb) info frame
Stack level 0, frame at 0x200ffa8:
pc = 0x4ec in CT32B1_IRQHandler (../src/timer.c:67); saved pc = 0xfffffff9
called by frame at 0x200ffc8
source language c.
Arglist at 0x200ffa0, args:
Locals at 0x200ffa0, Previous frame's sp is 0x200ffa8
Saved registers:
r7 at 0x200ffa0, lr at 0x200ffa4
(gdb) x/x 0xfffffff9
0xfffffff9: Cannot access memory at address 0xfffffff9
(gdb) finish
Run till exit from #0 CT32B1_IRQHandler () at ../src/timer.c:67
Ed:15: Target error from Set break/watch: Et:96: Pseudo-address (0xFFFFFFxx) for EXC_RETURN is invalid (GDB error?)
Warning:
Cannot insert hardware breakpoint 0.
Could not insert hardware breakpoints:
You may have requested too many hardware breakpoints/watchpoints.
Command aborted.
even some debug probe can't set hardware breakpoint on the magic
address too,
(gdb) hbreak *0xfffffff9
Hardware assisted breakpoint 2 at 0xfffffff9
(gdb) c
Continuing.
Ed:15: Target error from Set break/watch: Et:96: Pseudo-address (0xFFFFFFxx) for EXC_RETURN is invalid (GDB error?)
Warning:
Cannot insert hardware breakpoint 2.
Could not insert hardware breakpoints:
You may have requested too many hardware breakpoints/watchpoints.
Command aborted.
The problem described above is quite similar to PR 8841, in which GDB
can't set breakpoint on signal trampoline, which is mapped to a read-only
page by kernel. The rationale of this patch is to skip "unwritable"
frames when looking for caller frames in command "finish", and a new
gdbarch method code_of_frame_writable is added. This patch fixes
the problem on ARM cortex-m target, but it can be used to fix
PR 8841 too.
gdb:
2016-05-10 Yao Qi <yao.qi@arm.com>
* arch-utils.c (default_code_of_frame_writable): New function.
* arch-utils.h (default_code_of_frame_writable): Declare.
* arm-tdep.c (arm_code_of_frame_writable): New function.
(arm_gdbarch_init): Install gdbarch method
code_of_frame_writable if the target is M-profile.
* frame.c (skip_unwritable_frames): New function.
* frame.h (skip_unwritable_frames): Declare.
* gdbarch.sh (code_of_frame_writable): New.
* gdbarch.c, gdbarch.h: Re-generated.
* infcmd.c (finish_command): Call skip_unwritable_frames.
When we're looking at a tracefile trace frame where registers are not
available, and the tracepoint has only one location, we supply
the location's address as the PC register. However, this only works
if PC is not a pseudo register, and individual architectures may want
to guess more registers. Add a gdbarch hook that will handle that.
gdb/ChangeLog:
* arch-utils.c (default_guess_tracepoint_registers): New function.
* arch-utils.h (default_guess_tracepoint_registers): New prototype.
* gdbarch.c: Regenerate.
* gdbarch.h: Regenerate.
* gdbarch.sh: Add guess_tracepoint_registers hook.
* tracefile.c (tracefile_fetch_registers): Use the new gdbarch hook.
This patch removes the isize output argument from the
fast_tracepoint_valid_at gdbarch hook. It was used to return the size
of the instruction that needs to be replaced when installing a fast
tracepoint. Instead of getting this value from the
fast_tracepoint_valid_at hook, we can call the gdb_insn_length function.
If we do not do this, then architectures which do not have a restriction
on where to install the fast tracepoint will send uninitialized memory
off to GDBserver. See remote_download_tracepoint:
~~~
int isize;
if (gdbarch_fast_tracepoint_valid_at (target_gdbarch (),
tpaddr, &isize, NULL))
xsnprintf (buf + strlen (buf), BUF_SIZE - strlen (buf), ":F%x",
isize);
~~~
The default implementation of fast_tracepoint_valid_at will not set
isize resulting in uninitialized memory being sent. Later on, GDBserver
could use this information to compute a jump offset.
gdb/ChangeLog:
* arch-utils.c (default_fast_tracepoint_valid_at): Remove unused
isize argument.
* arch-utils.h (default_fast_tracepoint_valid_at): Likewise.
* breakpoint.c (check_fast_tracepoint_sals): Adjust call to
gdbarch_fast_tracepoint_valid_at.
* gdbarch.sh (fast_tracepoint_valid_at): Remove isize argument.
* gdbarch.h: Regenerate.
* gdbarch.c: Regenerate.
* i386-tdep.c (i386_fast_tracepoint_valid_at): Remove isize
argument. Do not set it.
* remote.c (remote_download_tracepoint): Adjust call to
gdbarch_fast_tracepoint_valid_at. Call gdb_insn_length to get
the instruction length.
Add a new gdbarch method to get the length of an addressable memory unit
for a given architecture. The default implementation returns 1.
gdb/ChangeLog:
* arch-utils.h (default_addressable_memory_unit_size): New.
* arch-utils.c (default_addressable_memory_unit_size): New.
* gdbarch.sh (addressable_memory_unit_size): New.
* gdbarch.h: Re-generate.
* gdbarch.c: Re-generate.
Currently inferior memory is allocated by inferior mmap() but it is never
deallocated; despite the injected objfile incl. its symbols is freed. This was
intentional so that one can do for example:
inferior:
char *str = "foo";
GDB:
(gdb) compile code str = "bar";
I believe later patches will be needed to introduce full control over keeping
vs. discarding the injected module as being discussed in:
compile: objfiles lifetime UI
https://sourceware.org/ml/gdb/2015-04/msg00051.html
Message-ID: <20150429135735.GA16974@host1.jankratochvil.net>
https://sourceware.org/ml/gdb/2015-05/msg00007.html
As decided by Phil it is better not to leak inferior pages as users can
workaround the issue above for example by:
(gdb) compile code str = strdup ("bar");
I have checked that in fact gdb/doc/ (written by Phil) already expects the
injected code will be unmapped so that does not need to be changed:
compile code int ff = 5; p = &ff;
In this example, @code{p} would point to @code{ff} when the
@code{compile} command is executing the source code provided to it.
However, as variables in the (example) program persist with their
assigned values, the variable @code{p} would point to an invalid
location when the command exists.
gdb/ChangeLog
2015-04-28 Jan Kratochvil <jan.kratochvil@redhat.com>
* arch-utils.c (default_infcall_munmap): New.
* arch-utils.h (default_infcall_munmap): New declaration.
* compile/compile-object-load.c (struct munmap_list, munmap_list_add)
(munmap_list_free, munmap_listp_free_cleanup): New.
(struct setup_sections_data): Add field munmap_list_headp.
(setup_sections): Call munmap_list_add.
(compile_object_load): New variable munmap_list_head, initialize
setup_sections_data.munmap_list_headp, return munmap_list_head.
* compile/compile-object-load.h (struct munmap_list): New declaration.
(struct compile_module): Add field munmap_list_head.
(munmap_list_free): New declaration.
* compile/compile-object-run.c (struct do_module_cleanup): Add field
munmap_list_head.
(do_module_cleanup): Call munmap_list_free.
(compile_object_run): Pass munmap_list_head to do_module_cleanup.
* gdbarch.c: Regenerate.
* gdbarch.h: Regenerate.
* gdbarch.sh (infcall_munmap): New.
* linux-tdep.c (linux_infcall_munmap): New.
(linux_init_abi): Install it.
gdb/testsuite/ChangeLog
2015-04-28 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.compile/compile.exp (keep jit in memory): Rename to ...
(do not keep jit in memory): ... this.
(expect 5): Change it to ...
(expect no 5): ... this.
We concluded that gdbarch_in_function_epilogue_p is misnamed, since it
returns true if the given PC is one instruction after the one that
destroyed the stack (which isn't necessarily inside an epilogue),
therefore it should be renamed to stack_frame_destroyed_p.
I also took the liberty of renaming the arch-specific implementations to
*_stack_frame_destroyed_p as well for consistency.
gdb:
2015-05-26 Martin Galvan <martin.galvan@tallertechnologies.com>
* amd64-tdep.c: Replace in_function_epilogue_p with
stack_frame_destroyed_p throughout.
* arch-utils.c: Ditto.
* arch-utils.h: Ditto.
* arm-tdep.c: Ditto.
* breakpoint.c: Ditto.
* gdbarch.sh: Ditto.
* hppa-tdep.c: Ditto.
* i386-tdep.c: Ditto.
* mips-tdep.c: Ditto.
* nios2-tdep.c: Ditto.
* rs6000-tdep.c: Ditto.
* s390-linux-tdep.c: Ditto.
* score-tdep.c: Ditto.
* sh-tdep.c: Ditto.
* sparc-tdep.c: Ditto.
* sparc-tdep.h: Ditto.
* sparc64-tdep.c: Ditto.
* spu-tdep.c: Ditto.
* tic6x-tdep.c: Ditto.
* tilegx-tdep.c: Ditto.
* xstormy16-tdep.c: Ditto.
* gdbarch.c, gdbarch.h: Re-generated.
This commit introduces a new inline common function "startswith"
which takes two string arguments and returns nonzero if the first
string starts with the second. It also updates the 295 places
where this logic was written out longhand to use the new function.
gdb/ChangeLog:
* common/common-utils.h (startswith): New inline function.
All places where this logic was used updated to use the above.
gdb has to inform libcc1.so of the target being used, so that the
correct compiler can be invoked. The compiler is invoked using the
GNU configury triplet prefix, e.g., "x86_64-unknown-linux-gnu-gcc".
In order for this to work we need to map the gdbarch to the GNU
configury triplet arch. In most cases these are identical; however,
the x86 family poses some problems, as the BFD arch names are quite
different from the GNU triplet names. So, we introduce a new gdbarch
method for this. A regular expression is used because there are
various valid values for the arch prefix in the triplet.
This patch also updates the osabi code to associate a regular
expression with the OS ABI. I have only added a concrete value for
Linux. Note that the "-gnu" part is optional, at least on Fedora it
is omitted from the installed GCC executable's name.
gdb/ChangeLog
2014-12-12 Tom Tromey <tromey@redhat.com>
Jan Kratochvil <jan.kratochvil@redhat.com>
* osabi.h (osabi_triplet_regexp): Declare.
* osabi.c (struct osabi_names): New.
(gdb_osabi_names): Change type to struct osabi_names. Update
values.
(gdbarch_osabi_name): Update.
(osabi_triplet_regexp): New function.
(osabi_from_tdesc_string, _initialize_gdb_osabi): Update.
* i386-tdep.c (i386_gnu_triplet_regexp): New method.
(i386_elf_init_abi, i386_go32_init_abi, i386_gdbarch_init): Call
set_gdbarch_gnu_triplet_regexp.
* gdbarch.sh (gnu_triplet_regexp): New method.
* gdbarch.c, gdbarch.h: Rebuild.
* arch-utils.h (default_gnu_triplet_regexp): Declare.
* arch-utils.c (default_gnu_triplet_regexp): New function.
The compiler needed two new gdbarch methods.
The infcall_mmap method allocates memory in the inferior.
This is used when inserting the object code.
The gcc_target_options method computes some arch-specific gcc options
to pass to the compiler. This is used to ensure that gcc generates
object code for the correct architecture.
gdb/ChangeLog
2014-12-12 Jan Kratochvil <jan.kratochvil@redhat.com>
* arch-utils.c (default_infcall_mmap)
(default_gcc_target_options): New functions.
* arch-utils.h (GDB_MMAP_PROT_READ, GDB_MMAP_PROT_WRITE)
(GDB_MMAP_PROT_EXEC): Define.
(default_infcall_mmap, default_gcc_target_options): Declare.
* gdbarch.h: Rebuild.
* gdbarch.c: Rebuild.
* gdbarch.sh (infcall_mmap, gcc_target_options): New methods.
1. Background information
The MIPS architecture, as originally designed and implemented in
mid-1980s has a uniform instruction word size that is 4 bytes, naturally
aligned. As such all MIPS instructions are located at addresses that
have their bits #1 and #0 set to zeroes, and any attempt to execute an
instruction from an address that has any of the two bits set to one
causes an address error exception. This may for example happen when a
jump-register instruction is executed whose register value used as the
jump target has any of these bits set.
Then in mid 1990s LSI sought a way to improve code density for their
TinyRISC family of MIPS cores and invented an alternatively encoded
instruction set in a joint effort with MIPS Technologies (then a
subsidiary of SGI). The new instruction set has been named the MIPS16
ASE (Application-Specific Extension) and uses a variable instruction
word size, which is 2 bytes (as the name of the ASE suggests) for most,
but there are a couple of exceptions that take 4 bytes, and then most of
the 2-byte instructions can be treated with a 2-byte extension prefix to
expand the range of the immediate operands used.
As a result instructions are no longer 4-byte aligned, instead they are
aligned to a multiple of 2. That left the bit #0 still unused for code
references, be it for the standard MIPS (i.e. as originally invented) or
for the MIPS16 instruction set, and based on that observation a clever
trick was invented that on one hand allowed the processor to be
seamlessly switched between the two instruction sets at any time at the
run time while on the other avoided the introduction of any special
control register to do that.
So it is the bit #0 of the instruction address that was chosen as the
selector and named the ISA bit. Any instruction executed at an even
address is interpreted as a standard MIPS instruction (the address still
has to have its bit #1 clear), any instruction executed at an odd
address is interpreted as a MIPS16 instruction.
To switch between modes ordinary jump instructions are used, such as
used for function calls and returns, specifically the bit #0 of the
source register used in jump-register instructions selects the execution
(ISA) mode for the following piece of code to be interpreted in.
Additionally new jump-immediate instructions were added that flipped the
ISA bit to select the opposite mode upon execution. They were
considered necessary to avoid the need to make register jumps in all
cases as the original jump-immediate instructions provided no way to
change the bit #0 at all.
This was all important for cases where standard MIPS and MIPS16 code had
to be mixed, either for compatibility with the existing binary code base
or to access resources not reachable from MIPS16 code (the MIPS16
instruction set only provides access to general-purpose registers, and
not for example floating-point unit registers or privileged coprocessor
0 registers) -- pieces of code in the opposite mode can be executed as
ordinary subroutine calls.
A similar approach has been more recently adopted for the MIPS16
replacement instruction set defined as the so called microMIPS ASE.
This is another instruction set encoding introduced to the MIPS
architecture. Just like the MIPS16 ASE, the microMIPS instruction set
uses a variable-length encoding, where each instruction takes a multiple
of 2 bytes. The ISA bit has been reused and for microMIPS-capable
processors selects between the standard MIPS and the microMIPS mode
instead.
2. Statement of the problem
To put it shortly, MIPS16 and microMIPS code pointers used by GDB are
different to these observed at the run time. This results in the same
expressions being evaluated producing different results in GDB and in
the program being debugged. Obviously it's the results obtained at the
run time that are correct (they define how the program behaves) and
therefore by definition the results obtained in GDB are incorrect.
A bit longer description will record that obviously at the run time the
ISA bit has to be set correctly (refer to background information above
if unsure why so) or the program will not run as expected. This is
recorded in all the executable file structures used at the run time: the
dynamic symbol table (but not always the static one!), the GOT, and
obviously in all the addresses embedded in code or data of the program
itself, calculated by applying the appropriate relocations at the static
link time.
While a program is being processed by GDB, the ISA bit is stripped off
from any code addresses, presumably to make them the same as the
respective raw memory byte address used by the processor to access the
instruction in the instruction fetch access cycle. This stripping is
actually performed outside GDB proper, in BFD, specifically
_bfd_mips_elf_symbol_processing (elfxx-mips.c, see the piece of code at
the very bottom of that function, starting with an: "If this is an
odd-valued function symbol, assume it's a MIPS16 or microMIPS one."
comment).
This function is also responsible for symbol table dumps made by
`objdump' too, so you'll never see the ISA bit reported there by that
tool, you need to use `readelf'.
This is however unlike what is ever done at the run time, the ISA bit
once present is never stripped off, for example a cast like this:
(short *) main
will not strip the ISA bit off and if the resulting pointer is intended
to be used to access instructions as data, for example for software
instruction decoding (like for fault recovery or emulation in a signal
handler) or for self-modifying code then the bit still has to be
stripped off by an explicit AND operation.
This is probably best illustrated with a simple real program example.
Let's consider the following simple program:
$ cat foobar.c
int __attribute__ ((mips16)) foo (void)
{
return 1;
}
int __attribute__ ((mips16)) bar (void)
{
return 2;
}
int __attribute__ ((nomips16)) foo32 (void)
{
return 3;
}
int (*foo32p) (void) = foo32;
int (*foop) (void) = foo;
int fooi = (int) foo;
int
main (void)
{
return foop ();
}
$
This is plain C with no odd tricks, except from the instruction mode
attributes. They are not necessary to trigger this problem, I just put
them here so that the program can be contained in a single source file
and to make it obvious which function is MIPS16 code and which is not.
Let's try it with Linux, so that everyone can repeat this experiment:
$ mips-linux-gnu-gcc -mips16 -g -O2 -o foobar foobar.c
$
Let's have a look at some interesting symbols:
$ mips-linux-gnu-readelf -s foobar | egrep 'table|foo|bar'
Symbol table '.dynsym' contains 7 entries:
Symbol table '.symtab' contains 95 entries:
55: 00000000 0 FILE LOCAL DEFAULT ABS foobar.c
66: 0040068c 4 FUNC GLOBAL DEFAULT [MIPS16] 12 bar
68: 00410848 4 OBJECT GLOBAL DEFAULT 21 foo32p
70: 00410844 4 OBJECT GLOBAL DEFAULT 21 foop
78: 00400684 8 FUNC GLOBAL DEFAULT 12 foo32
80: 00400680 4 FUNC GLOBAL DEFAULT [MIPS16] 12 foo
88: 00410840 4 OBJECT GLOBAL DEFAULT 21 fooi
$
Hmm, no sight of the ISA bit, but notice how foo and bar (but not
foo32!) have been marked as MIPS16 functions (ELF symbol structure's
`st_other' field is used for that).
So let's try to run and poke at this program with GDB. I'll be using a
native system for simplicity (I'll be using ellipses here and there to
remove unrelated clutter):
$ ./foobar
$ echo $?
1
$
So far, so good.
$ gdb ./foobar
[...]
(gdb) break main
Breakpoint 1 at 0x400490: file foobar.c, line 23.
(gdb) run
Starting program: .../foobar
Breakpoint 1, main () at foobar.c:23
23 return foop ();
(gdb)
Yay, it worked! OK, so let's poke at it:
(gdb) print main
$1 = {int (void)} 0x400490 <main>
(gdb) print foo32
$2 = {int (void)} 0x400684 <foo32>
(gdb) print foo32p
$3 = (int (*)(void)) 0x400684 <foo32>
(gdb) print bar
$4 = {int (void)} 0x40068c <bar>
(gdb) print foo
$5 = {int (void)} 0x400680 <foo>
(gdb) print foop
$6 = (int (*)(void)) 0x400681 <foo>
(gdb)
A-ha! Here's the difference and finally the ISA bit!
(gdb) print /x fooi
$7 = 0x400681
(gdb) p/x $pc
p/x $pc
$8 = 0x400491
(gdb)
And here as well...
(gdb) advance foo
foo () at foobar.c:4
4 }
(gdb) disassemble
Dump of assembler code for function foo:
0x00400680 <+0>: jr ra
0x00400682 <+2>: li v0,1
End of assembler dump.
(gdb) finish
Run till exit from #0 foo () at foobar.c:4
main () at foobar.c:24
24 }
Value returned is $9 = 1
(gdb) continue
Continuing.
[Inferior 1 (process 14103) exited with code 01]
(gdb)
So let's be a bit inquisitive...
(gdb) run
Starting program: .../foobar
Breakpoint 1, main () at foobar.c:23
23 return foop ();
(gdb)
Actually we do not like to run foo here at all. Let's run bar instead!
(gdb) set foop = bar
(gdb) print foop
$10 = (int (*)(void)) 0x40068c <bar>
(gdb)
Hmm, no ISA bit. Is it going to work?
(gdb) advance bar
bar () at foobar.c:9
9 }
(gdb) p/x $pc
$11 = 0x40068c
(gdb) disassemble
Dump of assembler code for function bar:
=> 0x0040068c <+0>: jr ra
0x0040068e <+2>: li v0,2
End of assembler dump.
(gdb) finish
Run till exit from #0 bar () at foobar.c:9
Program received signal SIGILL, Illegal instruction.
bar () at foobar.c:9
9 }
(gdb)
Oops!
(gdb) p/x $pc
$12 = 0x40068c
(gdb)
We're still there!
(gdb) continue
Continuing.
Program terminated with signal SIGILL, Illegal instruction.
The program no longer exists.
(gdb)
So let's try something else:
(gdb) run
Starting program: .../foobar
Breakpoint 1, main () at foobar.c:23
23 return foop ();
(gdb) set foop = foo
(gdb) advance foo
foo () at foobar.c:4
4 }
(gdb) disassemble
Dump of assembler code for function foo:
=> 0x00400680 <+0>: jr ra
0x00400682 <+2>: li v0,1
End of assembler dump.
(gdb) finish
Run till exit from #0 foo () at foobar.c:4
Program received signal SIGILL, Illegal instruction.
foo () at foobar.c:4
4 }
(gdb) continue
Continuing.
Program terminated with signal SIGILL, Illegal instruction.
The program no longer exists.
(gdb)
The same problem!
(gdb) run
Starting program:
/net/build2-lucid-cs/scratch/macro/mips-linux-fsf-gcc/isa-bit/foobar
Breakpoint 1, main () at foobar.c:23
23 return foop ();
(gdb) set foop = foo32
(gdb) advance foo32
foo32 () at foobar.c:14
14 }
(gdb) disassemble
Dump of assembler code for function foo32:
=> 0x00400684 <+0>: jr ra
0x00400688 <+4>: li v0,3
End of assembler dump.
(gdb) finish
Run till exit from #0 foo32 () at foobar.c:14
main () at foobar.c:24
24 }
Value returned is $14 = 3
(gdb) continue
Continuing.
[Inferior 1 (process 14113) exited with code 03]
(gdb)
That did work though, so it's the ISA bit only!
(gdb) quit
Enough!
That's the tip of the iceberg only though. So let's rebuild the
executable with some dynamic symbols:
$ mips-linux-gnu-gcc -mips16 -Wl,--export-dynamic -g -O2 -o foobar-dyn foobar.c
$ mips-linux-gnu-readelf -s foobar-dyn | egrep 'table|foo|bar'
Symbol table '.dynsym' contains 32 entries:
6: 004009cd 4 FUNC GLOBAL DEFAULT 12 bar
8: 00410b88 4 OBJECT GLOBAL DEFAULT 21 foo32p
9: 00410b84 4 OBJECT GLOBAL DEFAULT 21 foop
15: 004009c4 8 FUNC GLOBAL DEFAULT 12 foo32
17: 004009c1 4 FUNC GLOBAL DEFAULT 12 foo
25: 00410b80 4 OBJECT GLOBAL DEFAULT 21 fooi
Symbol table '.symtab' contains 95 entries:
55: 00000000 0 FILE LOCAL DEFAULT ABS foobar.c
69: 004009cd 4 FUNC GLOBAL DEFAULT 12 bar
71: 00410b88 4 OBJECT GLOBAL DEFAULT 21 foo32p
72: 00410b84 4 OBJECT GLOBAL DEFAULT 21 foop
79: 004009c4 8 FUNC GLOBAL DEFAULT 12 foo32
81: 004009c1 4 FUNC GLOBAL DEFAULT 12 foo
89: 00410b80 4 OBJECT GLOBAL DEFAULT 21 fooi
$
OK, now the ISA bit is there for a change, but the MIPS16 `st_other'
attribute gone, hmm... What does `objdump' do then:
$ mips-linux-gnu-objdump -Tt foobar-dyn | egrep 'SYMBOL|foo|bar'
foobar-dyn: file format elf32-tradbigmips
SYMBOL TABLE:
00000000 l df *ABS* 00000000 foobar.c
004009cc g F .text 00000004 0xf0 bar
00410b88 g O .data 00000004 foo32p
00410b84 g O .data 00000004 foop
004009c4 g F .text 00000008 foo32
004009c0 g F .text 00000004 0xf0 foo
00410b80 g O .data 00000004 fooi
DYNAMIC SYMBOL TABLE:
004009cc g DF .text 00000004 Base 0xf0 bar
00410b88 g DO .data 00000004 Base foo32p
00410b84 g DO .data 00000004 Base foop
004009c4 g DF .text 00000008 Base foo32
004009c0 g DF .text 00000004 Base 0xf0 foo
00410b80 g DO .data 00000004 Base fooi
$
Hmm, the attribute (0xf0, printed raw) is back, and the ISA bit gone
again.
Let's have a look at some DWARF-2 records GDB uses (I'll be stripping
off a lot here for brevity) -- debug info:
$ mips-linux-gnu-readelf -wi foobar
Contents of the .debug_info section:
[...]
Compilation Unit @ offset 0x88:
Length: 0xbb (32-bit)
Version: 4
Abbrev Offset: 62
Pointer Size: 4
<0><93>: Abbrev Number: 1 (DW_TAG_compile_unit)
<94> DW_AT_producer : (indirect string, offset: 0x19e): GNU C 4.8.0 20120513 (experimental) -meb -mips16 -march=mips32r2 -mhard-float -mllsc -mplt -mno-synci -mno-shared -mabi=32 -g -O2
<98> DW_AT_language : 1 (ANSI C)
<99> DW_AT_name : (indirect string, offset: 0x190): foobar.c
<9d> DW_AT_comp_dir : (indirect string, offset: 0x225): [...]
<a1> DW_AT_ranges : 0x0
<a5> DW_AT_low_pc : 0x0
<a9> DW_AT_stmt_list : 0x27
<1><ad>: Abbrev Number: 2 (DW_TAG_subprogram)
<ae> DW_AT_external : 1
<ae> DW_AT_name : foo
<b2> DW_AT_decl_file : 1
<b3> DW_AT_decl_line : 1
<b4> DW_AT_prototyped : 1
<b4> DW_AT_type : <0xc2>
<b8> DW_AT_low_pc : 0x400680
<bc> DW_AT_high_pc : 0x400684
<c0> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<c2> DW_AT_GNU_all_call_sites: 1
<1><c2>: Abbrev Number: 3 (DW_TAG_base_type)
<c3> DW_AT_byte_size : 4
<c4> DW_AT_encoding : 5 (signed)
<c5> DW_AT_name : int
<1><c9>: Abbrev Number: 4 (DW_TAG_subprogram)
<ca> DW_AT_external : 1
<ca> DW_AT_name : (indirect string, offset: 0x18a): foo32
<ce> DW_AT_decl_file : 1
<cf> DW_AT_decl_line : 11
<d0> DW_AT_prototyped : 1
<d0> DW_AT_type : <0xc2>
<d4> DW_AT_low_pc : 0x400684
<d8> DW_AT_high_pc : 0x40068c
<dc> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<de> DW_AT_GNU_all_call_sites: 1
<1><de>: Abbrev Number: 2 (DW_TAG_subprogram)
<df> DW_AT_external : 1
<df> DW_AT_name : bar
<e3> DW_AT_decl_file : 1
<e4> DW_AT_decl_line : 6
<e5> DW_AT_prototyped : 1
<e5> DW_AT_type : <0xc2>
<e9> DW_AT_low_pc : 0x40068c
<ed> DW_AT_high_pc : 0x400690
<f1> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<f3> DW_AT_GNU_all_call_sites: 1
<1><f3>: Abbrev Number: 5 (DW_TAG_subprogram)
<f4> DW_AT_external : 1
<f4> DW_AT_name : (indirect string, offset: 0x199): main
<f8> DW_AT_decl_file : 1
<f9> DW_AT_decl_line : 21
<fa> DW_AT_prototyped : 1
<fa> DW_AT_type : <0xc2>
<fe> DW_AT_low_pc : 0x400490
<102> DW_AT_high_pc : 0x4004a4
<106> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<108> DW_AT_GNU_all_tail_call_sites: 1
[...]
$
-- no sign of the ISA bit anywhere -- frame info:
$ mips-linux-gnu-readelf -wf foobar
[...]
Contents of the .debug_frame section:
00000000 0000000c ffffffff CIE
Version: 1
Augmentation: ""
Code alignment factor: 1
Data alignment factor: -4
Return address column: 31
DW_CFA_def_cfa_register: r29
DW_CFA_nop
00000010 0000000c 00000000 FDE cie=00000000 pc=00400680..00400684
00000020 0000000c 00000000 FDE cie=00000000 pc=00400684..0040068c
00000030 0000000c 00000000 FDE cie=00000000 pc=0040068c..00400690
00000040 00000018 00000000 FDE cie=00000000 pc=00400490..004004a4
DW_CFA_advance_loc: 6 to 00400496
DW_CFA_def_cfa_offset: 32
DW_CFA_offset: r31 at cfa-4
DW_CFA_advance_loc: 6 to 0040049c
DW_CFA_restore: r31
DW_CFA_def_cfa_offset: 0
DW_CFA_nop
DW_CFA_nop
DW_CFA_nop
[...]
$
-- no sign of the ISA bit anywhere -- range info (GDB doesn't use arange):
$ mips-linux-gnu-readelf -wR foobar
Contents of the .debug_ranges section:
Offset Begin End
00000000 00400680 00400690
00000000 00400490 004004a4
00000000 <End of list>
$
-- no sign of the ISA bit anywhere -- line info:
$ mips-linux-gnu-readelf -wl foobar
Raw dump of debug contents of section .debug_line:
[...]
Offset: 0x27
Length: 78
DWARF Version: 2
Prologue Length: 31
Minimum Instruction Length: 1
Initial value of 'is_stmt': 1
Line Base: -5
Line Range: 14
Opcode Base: 13
Opcodes:
Opcode 1 has 0 args
Opcode 2 has 1 args
Opcode 3 has 1 args
Opcode 4 has 1 args
Opcode 5 has 1 args
Opcode 6 has 0 args
Opcode 7 has 0 args
Opcode 8 has 0 args
Opcode 9 has 1 args
Opcode 10 has 0 args
Opcode 11 has 0 args
Opcode 12 has 1 args
The Directory Table is empty.
The File Name Table:
Entry Dir Time Size Name
1 0 0 0 foobar.c
Line Number Statements:
Extended opcode 2: set Address to 0x400681
Special opcode 6: advance Address by 0 to 0x400681 and Line by 1 to 2
Special opcode 7: advance Address by 0 to 0x400681 and Line by 2 to 4
Special opcode 55: advance Address by 3 to 0x400684 and Line by 8 to 12
Special opcode 7: advance Address by 0 to 0x400684 and Line by 2 to 14
Advance Line by -7 to 7
Special opcode 131: advance Address by 9 to 0x40068d and Line by 0 to 7
Special opcode 7: advance Address by 0 to 0x40068d and Line by 2 to 9
Advance PC by 3 to 0x400690
Extended opcode 1: End of Sequence
Extended opcode 2: set Address to 0x400491
Advance Line by 21 to 22
Copy
Special opcode 6: advance Address by 0 to 0x400491 and Line by 1 to 23
Special opcode 60: advance Address by 4 to 0x400495 and Line by -1 to 22
Special opcode 34: advance Address by 2 to 0x400497 and Line by 1 to 23
Special opcode 62: advance Address by 4 to 0x40049b and Line by 1 to 24
Special opcode 32: advance Address by 2 to 0x40049d and Line by -1 to 23
Special opcode 6: advance Address by 0 to 0x40049d and Line by 1 to 24
Advance PC by 7 to 0x4004a4
Extended opcode 1: End of Sequence
[...]
-- a-ha, the ISA bit is there! However it's not always right for some
reason, I don't have a small test case to show it, but here's an excerpt
from MIPS16 libc, a prologue of a function:
00019630 <__libc_init_first>:
19630: e8a0 jrc ra
19632: 6500 nop
00019634 <_init>:
19634: f000 6a11 li v0,17
19638: f7d8 0b08 la v1,15e00 <_DYNAMIC+0x15c54>
1963c: f400 3240 sll v0,16
19640: e269 addu v0,v1
19642: 659a move gp,v0
19644: 64f6 save 48,ra,s0-s1
19646: 671c move s0,gp
19648: d204 sw v0,16(sp)
1964a: f352 984c lw v0,-27828(s0)
1964e: 6724 move s1,a0
and the corresponding DWARF-2 line info:
Line Number Statements:
Extended opcode 2: set Address to 0x19631
Advance Line by 44 to 45
Copy
Special opcode 8: advance Address by 0 to 0x19631 and Line by 3 to 48
Special opcode 66: advance Address by 4 to 0x19635 and Line by 5 to 53
Advance PC by constant 17 to 0x19646
Special opcode 25: advance Address by 1 to 0x19647 and Line by 6 to 59
Advance Line by -6 to 53
Special opcode 33: advance Address by 2 to 0x19649 and Line by 0 to 53
Special opcode 39: advance Address by 2 to 0x1964b and Line by 6 to 59
Advance Line by -6 to 53
Special opcode 61: advance Address by 4 to 0x1964f and Line by 0 to 53
-- see that "Advance PC by constant 17" there? It clears the ISA bit,
however code at 0x19646 is not standard MIPS code at all. For some
reason the constant is always 17, I've never seen DW_LNS_const_add_pc
used with any other value -- is that a binutils bug or what?
3. Solution:
I think we should retain the value of the ISA bit in code references,
that is effectively treat them as cookies as they indeed are (although
trivially calculated) rather than raw memory byte addresses.
In a perfect world both the static symbol table and the respective
DWARF-2 records should be fixed to include the ISA bit in all the cases.
I think however that this is infeasible.
All the uses of `_bfd_mips_elf_symbol_processing' can not necessarily be
tracked down. This function is used by `elf_slurp_symbol_table' that in
turn is used by `bfd_canonicalize_symtab' and
`bfd_canonicalize_dynamic_symtab', which are public interfaces.
Similarly DWARF-2 records are used outside GDB, one notable if a bit
questionable is the exception unwinder (libgcc/unwind-dw2.c) -- I have
identified at least bits in `execute_cfa_program' and
`uw_frame_state_for', both around the calls to `_Unwind_IsSignalFrame',
that would need an update as they effectively flip the ISA bit freely;
see also the comment about MASK_RETURN_ADDR in gcc/config/mips/mips.h.
But there may be more places. Any change in how DWARF-2 records are
produced would require an update there and would cause compatibility
problems with libgcc.a binaries already distributed; given that this is
a static library a complex change involving function renames would
likely be required.
I propose therefore to accept the existing inconsistencies and deal with
them entirely within GDB. I have figured out that the ISA bit lost in
various places can still be recovered as long as we have symbol
information -- that'll have the `st_other' attribute correctly set to
one of standard MIPS/MIPS16/microMIPS encoding.
Here's the resulting change. It adds a couple of new `gdbarch' hooks,
one to update symbol information with the ISA bit lost in
`_bfd_mips_elf_symbol_processing', and two other ones to adjust DWARF-2
records as they're processed. The ISA bit is set in each address
handled according to information retrieved from the symbol table for the
symbol spanning the address if any; limits are adjusted based on the
address they point to related to the respective base address.
Additionally minimal symbol information has to be adjusted accordingly
in its gdbarch hook.
With these changes in place some complications with ISA bit juggling in
the PC that never fully worked can be removed from the MIPS backend.
Conversely, the generic dynamic linker event special breakpoint symbol
handler has to be updated to call the minimal symbol gdbarch hook to
record that the symbol is a MIPS16 or microMIPS address if applicable or
the breakpoint will be set at the wrong address and either fail to work
or cause SIGTRAPs (this is because the symbol is handled early on and
bypasses regular symbol processing).
4. Results obtained
The change fixes the example above -- to repeat only the crucial steps:
(gdb) break main
Breakpoint 1 at 0x400491: file foobar.c, line 23.
(gdb) run
Starting program: .../foobar
Breakpoint 1, main () at foobar.c:23
23 return foop ();
(gdb) print foo
$1 = {int (void)} 0x400681 <foo>
(gdb) set foop = bar
(gdb) advance bar
bar () at foobar.c:9
9 }
(gdb) disassemble
Dump of assembler code for function bar:
=> 0x0040068d <+0>: jr ra
0x0040068f <+2>: li v0,2
End of assembler dump.
(gdb) finish
Run till exit from #0 bar () at foobar.c:9
main () at foobar.c:24
24 }
Value returned is $2 = 2
(gdb) continue
Continuing.
[Inferior 1 (process 14128) exited with code 02]
(gdb)
-- excellent!
The change removes about 90 failures per MIPS16 multilib in mips-sde-elf
testing too, results for MIPS16 are now similar to that for standard
MIPS; microMIPS results are a bit worse because of host-I/O problems in
QEMU used instead of MIPSsim for microMIPS testing only:
=== gdb Summary ===
# of expected passes 14299
# of unexpected failures 187
# of expected failures 56
# of known failures 58
# of unresolved testcases 11
# of untested testcases 52
# of unsupported tests 174
MIPS16:
=== gdb Summary ===
# of expected passes 14298
# of unexpected failures 187
# of unexpected successes 2
# of expected failures 54
# of known failures 58
# of unresolved testcases 12
# of untested testcases 52
# of unsupported tests 174
microMIPS:
=== gdb Summary ===
# of expected passes 14149
# of unexpected failures 201
# of unexpected successes 2
# of expected failures 54
# of known failures 58
# of unresolved testcases 7
# of untested testcases 53
# of unsupported tests 175
2014-12-12 Maciej W. Rozycki <macro@codesourcery.com>
Maciej W. Rozycki <macro@mips.com>
Pedro Alves <pedro@codesourcery.com>
gdb/
* gdbarch.sh (elf_make_msymbol_special): Change type to `F',
remove `predefault' and `invalid_p' initializers.
(make_symbol_special): New architecture method.
(adjust_dwarf2_addr, adjust_dwarf2_line): Likewise.
(objfile, symbol): New declarations.
* arch-utils.h (default_elf_make_msymbol_special): Remove
prototype.
(default_make_symbol_special): New prototype.
(default_adjust_dwarf2_addr): Likewise.
(default_adjust_dwarf2_line): Likewise.
* mips-tdep.h (mips_unmake_compact_addr): New prototype.
* arch-utils.c (default_elf_make_msymbol_special): Remove
function.
(default_make_symbol_special): New function.
(default_adjust_dwarf2_addr): Likewise.
(default_adjust_dwarf2_line): Likewise.
* dwarf2-frame.c (decode_frame_entry_1): Call
`gdbarch_adjust_dwarf2_addr'.
* dwarf2loc.c (dwarf2_find_location_expression): Likewise.
* dwarf2read.c (create_addrmap_from_index): Likewise.
(process_psymtab_comp_unit_reader): Likewise.
(add_partial_symbol): Likewise.
(add_partial_subprogram): Likewise.
(process_full_comp_unit): Likewise.
(read_file_scope): Likewise.
(read_func_scope): Likewise. Call `gdbarch_make_symbol_special'.
(read_lexical_block_scope): Call `gdbarch_adjust_dwarf2_addr'.
(read_call_site_scope): Likewise.
(dwarf2_ranges_read): Likewise.
(dwarf2_record_block_ranges): Likewise.
(read_attribute_value): Likewise.
(dwarf_decode_lines_1): Call `gdbarch_adjust_dwarf2_line'.
(new_symbol_full): Call `gdbarch_adjust_dwarf2_addr'.
* elfread.c (elf_symtab_read): Don't call
`gdbarch_elf_make_msymbol_special' if unset.
* mips-linux-tdep.c (micromips_linux_sigframe_validate): Strip
the ISA bit from the PC.
* mips-tdep.c (mips_unmake_compact_addr): New function.
(mips_elf_make_msymbol_special): Set the ISA bit in the symbol's
address appropriately.
(mips_make_symbol_special): New function.
(mips_pc_is_mips): Set the ISA bit before symbol lookup.
(mips_pc_is_mips16): Likewise.
(mips_pc_is_micromips): Likewise.
(mips_pc_isa): Likewise.
(mips_adjust_dwarf2_addr): New function.
(mips_adjust_dwarf2_line): Likewise.
(mips_read_pc, mips_unwind_pc): Keep the ISA bit.
(mips_addr_bits_remove): Likewise.
(mips_skip_trampoline_code): Likewise.
(mips_write_pc): Don't set the ISA bit.
(mips_eabi_push_dummy_call): Likewise.
(mips_o64_push_dummy_call): Likewise.
(mips_gdbarch_init): Install `mips_make_symbol_special',
`mips_adjust_dwarf2_addr' and `mips_adjust_dwarf2_line' gdbarch
handlers.
* solib.c (gdb_bfd_lookup_symbol_from_symtab): Get
target-specific symbol address adjustments.
* gdbarch.h: Regenerate.
* gdbarch.c: Regenerate.
2014-12-12 Maciej W. Rozycki <macro@codesourcery.com>
gdb/testsuite/
* gdb.base/func-ptrs.c: New file.
* gdb.base/func-ptrs.exp: New file.
breakpoint.c uses gdbarch_breakpoint_from_pc to determine whether a
breakpoint location points at a permanent breakpoint:
static int
bp_loc_is_permanent (struct bp_location *loc)
{
...
addr = loc->address;
bpoint = gdbarch_breakpoint_from_pc (loc->gdbarch, &addr, &len);
...
if (target_read_memory (loc->address, target_mem, len) == 0
&& memcmp (target_mem, bpoint, len) == 0)
retval = 1;
...
So I think we should default the gdbarch_skip_permanent_breakpoint
hook to advancing the PC by the length of the breakpoint instruction,
as determined by gdbarch_breakpoint_from_pc. I believe that simple
implementation does the right thing for most architectures. If
there's an oddball architecture where that doesn't work, then it
should override the hook, just like it should be overriding the hook
if there was no default anyway.
The only two implementation of skip_permanent_breakpoint are
i386_skip_permanent_breakpoint, for x86, and
hppa_skip_permanent_breakpoint, for PA-RISC/HP-UX
The x86 implementation is trivial, and can clearly be replaced by the
new default.
I don't know about the HP-UX one though, I know almost nothing about
PA. It may well be advancing the PC ends up being equivalent.
Otherwise, it must be that "jump $pc_after_bp" doesn't work either...
Tested on x86_64 Fedora 20 native and gdbserver.
gdb/
2014-11-12 Pedro Alves <palves@redhat.com>
* arch-utils.c (default_skip_permanent_breakpoint): New function.
* arch-utils.h (default_skip_permanent_breakpoint): New
declaration.
* gdbarch.sh (skip_permanent_breakpoint): Now an 'f' function.
Install default_skip_permanent_breakpoint as default method.
* i386-tdep.c (i386_skip_permanent_breakpoint): Delete function.
(i386_gdbarch_init): Don't install it.
* infrun.c (resume): Assume there's always a
gdbarch_skip_permanent_breakpoint implementation.
* gdbarch.h, gdbarch.c: Regenerate.
We have a case in solib-svr4.c where we could reuse symfile-mem.c's
vDSO range lookup. Since symfile-mem.c is not present in all
configurations solib-svr4.c is, move that lookup to a gdbarch hook.
This has the minor (good) side effect that we stop even trying the
target_auxv_search lookup against targets that don't have a concept of
a vDSO, in case symfile-mem.c happens to be linked in the build
(--enable-targets=all).
Tested on x86_64 Fedora 20.
gdb/
2014-10-10 Pedro Alves <palves@redhat.com>
* arch-utils.c (default_vsyscall_range): New function.
* arch-utils.h (default_vsyscall_range): New declaration.
* gdbarch.sh (vsyscall_range): New hook.
* gdbarch.h, gdbarch.c: Regenerate.
* linux-tdep.c (linux_vsyscall_range): New function.
(linux_init_abi): Install linux_vsyscall_range as
vsyscall_range gdbarch hook.
* memrange.c (address_in_mem_range): New function.
* memrange.h (address_in_mem_range): New declaration.
* symfile-mem.c (find_vdso_size): Delete function.
(add_vsyscall_page): Use gdbarch_vsyscall_range.
Move infrun.c declarations out of inferior.h to a new infrun.h file.
Tested by building on:
i686-w64-mingw32, enable-targets=all
x86_64-linux, enable-targets=all
i586-pc-msdosdjgpp
And also grepped the whole tree for each symbol moved to find where
infrun.h might be necessary.
gdb/
2014-05-22 Pedro Alves <palves@redhat.com>
* inferior.h (debug_infrun, debug_displaced, stop_on_solib_events)
(sync_execution, sched_multi, step_stop_if_no_debug, non_stop)
(disable_randomization, enum exec_direction_kind)
(execution_direction, stop_registers, start_remote)
(clear_proceed_status, proceed, resume, user_visible_resume_ptid)
(wait_for_inferior, normal_stop, get_last_target_status)
(prepare_for_detach, fetch_inferior_event, init_wait_for_inferior)
(insert_step_resume_breakpoint_at_sal)
(follow_inferior_reset_breakpoints, stepping_past_instruction_at)
(set_step_info, print_stop_event, signal_stop_state)
(signal_print_state, signal_pass_state, signal_stop_update)
(signal_print_update, signal_pass_update)
(update_signals_program_target, clear_exit_convenience_vars)
(displaced_step_dump_bytes, update_observer_mode)
(signal_catch_update, gdb_signal_from_command): Move
declarations ...
* infrun.h: ... to this new file.
* amd64-tdep.c: Include infrun.h.
* annotate.c: Include infrun.h.
* arch-utils.c: Include infrun.h.
* arm-linux-tdep.c: Include infrun.h.
* arm-tdep.c: Include infrun.h.
* break-catch-sig.c: Include infrun.h.
* breakpoint.c: Include infrun.h.
* common/agent.c: Include infrun.h instead of inferior.h.
* corelow.c: Include infrun.h.
* event-top.c: Include infrun.h.
* go32-nat.c: Include infrun.h.
* i386-tdep.c: Include infrun.h.
* inf-loop.c: Include infrun.h.
* infcall.c: Include infrun.h.
* infcmd.c: Include infrun.h.
* infrun.c: Include infrun.h.
* linux-fork.c: Include infrun.h.
* linux-nat.c: Include infrun.h.
* linux-thread-db.c: Include infrun.h.
* monitor.c: Include infrun.h.
* nto-tdep.c: Include infrun.h.
* procfs.c: Include infrun.h.
* record-btrace.c: Include infrun.h.
* record-full.c: Include infrun.h.
* remote-m32r-sdi.c: Include infrun.h.
* remote-mips.c: Include infrun.h.
* remote-notif.c: Include infrun.h.
* remote-sim.c: Include infrun.h.
* remote.c: Include infrun.h.
* reverse.c: Include infrun.h.
* rs6000-tdep.c: Include infrun.h.
* s390-linux-tdep.c: Include infrun.h.
* solib-irix.c: Include infrun.h.
* solib-osf.c: Include infrun.h.
* solib-svr4.c: Include infrun.h.
* target.c: Include infrun.h.
* top.c: Include infrun.h.
* windows-nat.c: Include infrun.h.
* mi/mi-interp.c: Include infrun.h.
* mi/mi-main.c: Include infrun.h.
* python/py-threadevent.c: Include infrun.h.
Add new methods to gdbarch for analyzing the instruction at a given address.
Implement those methods for i386 and amd64 architectures.
This is needed by "record btrace" to detect function calls in the
execution trace.
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
* amd64-tdep.c (amd64_classify_insn_at, amd64_insn_is_call)
(amd64_insn_is_ret, amd64_insn_is_jump, amd64_jmp_p): New.
(amd64_init_abi): Add insn_is_call, insn_is_ret, and insn_is_jump
to gdbarch.
* i386-tdep.c (i386_insn_is_call, i386_insn_is_ret)
(i386_insn_is_jump, i386_jmp_p): New.
(i386_gdbarch_init): Add insn_is_call, insn_is_ret, and
insn_is_jump to gdbarch.
* gdbarch.sh (insn_is_call, insn_is_ret, insn_is_jump): New.
* gdbarch.h: Regenerated.
* gdbarch.c: Regenerated.
* arch-utils.h (default_insn_is_call, default_insn_is_ret)
(default_insn_is_jump): New.
* arch-utils.c (default_insn_is_call, default_insn_is_ret)
(default_insn_is_jump): New.
Tom Tromey
Andrew Burgess
Joel Brobecker
Simon Marchi
Maciej W. Rozycki
Markus Metzger
Yao Qi
John Baldwin
Maciej W. Rozycki
Simon Marchi
Jiong Wang
Ulrich Weigand
Yao Qi
Marcin Kościelnicki
Pierre Langlois
Jan Kratochvil
Martin Galvan
Gary Benson
Tom Tromey
Maciej W. Rozycki
Pedro Alves