I find some gdb.python tests fail on arm-none-eabi target, because the
tests assume that memory on address 0x is inaccessible. Some tests
(in gdb.base) are aware of this, so do a "x 0" check first. However,
the code is copy-n-paste.
This patch is to move the "x 0" check to a procedure in lib/gdb.exp,
and get needed tests call it. The original code matches pattern
"0x0:\[ \t\]*Error accessing memory address 0x0\r\n$gdb_prompt $", but
I remove it from the new proc is_address_zero_readable, because GDB
doesn't emit such message any more.
gdb/testsuite:
2014-08-09 Yao Qi <yao@codesourcery.com>
* gdb.base/display.exp: Invoke is_address_zero_readable.
* gdb.guile/scm-value.exp (test_value_in_inferior): Likewise.
* gdb.python/py-value.exp (test_value_in_inferior): Likewise.
* gdb.base/hbreak-unmapped.exp: Return if
is_address_zero_readable returns true.
* gdb.base/signest.exp: Likewise.
* gdb.base/signull.exp: Likewise.
* gdb.base/sigbpt.exp: Likewise.
* gdb.guile/scm-disasm.exp: Do the test if
is_address_zero_readable returns false.
* gdb.guile/scm-pretty-print.exp (run_lang_tests): Likewise.
* gdb.python/py-arch.exp: Likewise.
* gdb.python/py-prettyprint.exp (run_lang_tests): Likewise.
* lib/gdb.exp (is_address_zero_readable): New proc.
hbreak-unmapped.exp assumes that memory at address 0 is unmapped or
unreadable, but on bare metal or uclinux targets, memory at address
0 is readable. For example, on arm-none-eabi, the vector table base
address is 0x0.
hbreak *0^M
Hardware assisted breakpoint 3 at 0x0: file
/scratch/yqi/arm-none-eabi-lite/obj/cs3-2014.11-999999-arm-none-eabi-i686-pc-linux-gnu/generated/arm-vector.S,
line 25.^M
(gdb) FAIL: gdb.base/hbreak-unmapped.exp: hbreak *0
info break^M
Num Type Disp Enb Address What^M
3 hw breakpoint keep y 0x00000000
/scratch/yqi/arm-none-eabi-lite/obj/cs3-2014.11-999999-arm-none-eabi-i686-pc-linux-gnu/generated/arm-vector.S:25^M
(gdb) FAIL: gdb.base/hbreak-unmapped.exp: info break shows hw breakpoint
delete $bpnum
This patch is to check whether address 0 is readable via command 'x 0'.
If it is, skip the test.
gdb/testsuite:
2014-06-06 Yao Qi <yao@codesourcery.com>
* gdb.base/hbreak-unmapped.exp: Read memory at address 0. If
readable, skip the test.
libraries.
As explained in
https://sourceware.org/ml/gdb-patches/2008-08/msg00361.html, after a
shared library was unloaded, we can no longer insert or remove
breakpoints into/from its (no longer present) code segment. That'll
fail with memory errors. However, that concern does not apply to
hardware breakpoints. By definition, hardware breakpoints are
implemented using a mechanism that is not dependent on being able to
modify the target's memory. Usually, by setting up CPU debug
registers. IOW, we should be able to set hw breakpoints in an
unmapped address. We don't seem to have a test that exercises that,
so this patch adds one.
I noticed the error supression because of a related issue -- the
target_insert_hw_breakpoint/target_remove_hw_breakpoint interfaces
don't really distinguish "not supported" from "error" return, and so
remote.c returns -1 in both cases. This results in hardware
breakpoints set in shared libraries silently ending up pending forever
even though the target doesn't actually support hw breakpoints.
(gdb) set breakpoint always-inserted on
(gdb) set remote Z-packet off
(gdb) info breakpoints
No breakpoints or watchpoints.
(gdb) hbreak shrfunc
Hardware assisted breakpoint 3 at 0x7ffff7dfb657: file ../../../src/gdb/testsuite/gdb.base/hbreak-in-shr-unsupported-shr.c, line 21.
(gdb) info break
Num Type Disp Enb Address What
3 hw breakpoint keep y <PENDING> shrfunc
After the patch we get the expected:
(gdb) hbreak shrfunc
Hardware assisted breakpoint 3 at 0x7ffff7dfb657: file ../../../src/gdb/testsuite/gdb.base/hbreak-in-shr-unsupported-shr.c, line 21.
Warning:
Cannot insert hardware breakpoint 3.
Could not insert hardware breakpoints:
You may have requested too many hardware breakpoints/watchpoints.
(gdb) info break
Num Type Disp Enb Address What
3 hw breakpoint keep y 0x00007ffff7dfb657 in shrfunc at ../../../src/gdb/testsuite/gdb.base/hbreak-in-shr-unsupported-shr.c:21
(HW breakpoints set in the main executable, when the target doesn't
support HW breakpoints always resulted in the latter output.)
We probably should improve the insert/remove interface to return a
different error code for unsupported. But I chose to fix the error
supression first, as it's a deeper and wider issue.
Tested on x86_64 Fedora 17, native and gdbserver.
gdb/
2014-04-23 Pedro Alves <palves@redhat.com>
* breakpoint.c (insert_bp_location, remove_breakpoint_1): If
the breakpoint is set in a shared library, only suppress
errors for software breakpoints, not hardware breakpoints.
gdb/testsuite/
2014-04-23 Pedro Alves <palves@redhat.com>
* gdb.base/hbreak-in-shr-unsupported-shr.c: New file.
* gdb.base/hbreak-in-shr-unsupported.c: New file.
* gdb.base/hbreak-in-shr-unsupported.exp: New file.
* gdb.base/hbreak-unmapped.c: New file.
* gdb.base/hbreak-unmapped.exp: New file.
* gdb.trace/qtro.exp (gdb_is_target_remote): Move ...
* lib/gdb.exp (gdb_is_target_remote): ... here.
