This patch makes thumb2_breakpoint static. When writing this patch,
I find the only reason we keep thumb2_breakpoint extern is that it
is used as an argument passed to arm_gdbserver_get_next_pcs. However,
field arm_thumb2_breakpoint is only used in a null check in
thumb_get_next_pcs_raw, so I wonder why do need to pass thumb2_breakpoint
to arm_gdbserver_get_next_pcs.
thumb2_breakpoint was added by Daniel Jacobowitz in order to support
single-step IT block
https://sourceware.org/ml/gdb-patches/2010-01/msg00624.html the logic
there was if we have 32-bit thumb-2 breakpoint defined, we can safely
single-step IT block, otherwise, we can't. Daniel didn't want to use
16-bit thumb BKPT instruction, because it triggers even on instruction
which should be executed. Secondly, using 16-bit thumb illegal
instruction on top of 32-bit thumb instruction may break the meaning of
original IT blocks, because the other 16-bit can be regarded as an
instruction. See more explanations from Daniel's kernel patch
http://www.spinics.net/lists/arm-kernel/msg80476.html
Let us back to this patch, GDB/GDBserver can safely single step
IT block if thumb2_breakpoint is defined, but the single step logic
doesn't have to know the thumb-2 breakpoint instruction. Only
breakpoint insertion mechanism decides to use which breakpoint
instruction. In the software single step code, instead of pass
thumb2_breakpoint, we can pass a boolean variable
has_thumb2_breakpoint indicate whether the target has thumb-2
breakpoint defined, which is equivalent to the original code.
Regression tested on arm-linux. No regression.
gdb:
2016-01-14 Yao Qi <yao.qi@linaro.org>
* arch/arm-get-next-pcs.c (arm_get_next_pcs_ctor): Change
argument arm_thumb2_breakpoint to has_thumb2_breakpoint.
(thumb_get_next_pcs_raw): Check has_thumb2_breakpoint
instead.
* arch/arm-get-next-pcs.h (struct arm_get_next_pcs)
<arm_thumb2_breakpoint>: Remove.
<has_thumb2_breakpoint>: New field.
(arm_get_next_pcs_ctor): Update declaration.
* arm-linux-tdep.c (arm_linux_software_single_step): Pass
1 to arm_get_next_pcs_ctor.
* arm-tdep.c (arm_software_single_step): Pass 0 to
arm_get_next_pcs_ctor.
gdb/gdbserver:
2016-01-14 Yao Qi <yao.qi@linaro.org>
* linux-aarch32-low.c (thumb2_breakpoint): Make it static.
* linux-aarch32-low.h (thumb2_breakpoint): Remove declaration.
* linux-arm-low.c (arm_gdbserver_get_next_pcs): Pass 1 to
arm_get_next_pcs_ctor.
When reading instruction, we should use byte_order_for_code instead
of byte_order.
gdb:
2016-01-13 Yao Qi <yao.qi@linaro.org>
* arch/arm-get-next-pcs.c (arm_get_next_pcs_raw): Use
byte_order_for_code to read instruction.
This patch makes arm_get_next_pcs_raw and thumb_get_next_pcs_raw
static.
gdb:
2016-01-06 Yao Qi <yao.qi@linaro.org>
* arch/arm-get-next-pcs.c (arm_get_next_pcs): Move it to some
lines below.
(thumb_get_next_pcs_raw): Make it static.
(arm_get_next_pcs_raw): Likewise.
* arch/arm-get-next-pcs.h (thumb_get_next_pcs_raw): Remove the
declaration.
(arm_get_next_pcs_raw): Likewise.
This patch teaches GDBServer how to software single step on ARM
linux by sharing code with GDB.
The arm_get_next_pcs function in GDB is now shared with GDBServer. So
that GDBServer can use the function to return the possible addresses of
the next PC.
A proper shared context was also needed so that we could share the code,
this context is described in the arm_get_next_pcs structure.
Testing :
No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/ChangeLog:
* Makefile.in (ALL_TARGET_OBS): Append arm-get-next-pcs.o,
arm-linux.o.
(ALLDEPFILES): Append arm-get-next-pcs.c, arm-linux.c
(arm-linux.o): New rule.
(arm-get-next-pcs.o): New rule.
* arch/arm-get-next-pcs.c: New file.
* arch/arm-get-next-pcs.h: New file.
* arch/arm-linux.h: New file.
* arch/arm-linux.c: New file.
* arm.c: Include common-regcache.c.
(thumb_advance_itstate): Moved from arm-tdep.c.
(arm_instruction_changes_pc): Likewise.
(thumb_instruction_changes_pc): Likewise.
(thumb2_instruction_changes_pc): Likewise.
(shifted_reg_val): Likewise.
* arm.h (submask): Move macro from arm-tdep.h
(bit): Likewise.
(bits): Likewise.
(sbits): Likewise.
(BranchDest): Likewise.
(thumb_advance_itstate): Moved declaration from arm-tdep.h
(arm_instruction_changes_pc): Likewise.
(thumb_instruction_changes_pc): Likewise.
(thumb2_instruction_changes_pc): Likewise.
(shifted_reg_val): Likewise.
* arm-linux-tdep.c: Include arch/arm.h, arch/arm-get-next-pcs.h
arch/arm-linux.h.
(arm_linux_get_next_pcs_ops): New struct.
(ARM_SIGCONTEXT_R0, ARM_UCONTEXT_SIGCONTEXT,
ARM_OLD_RT_SIGFRAME_SIGINFO, ARM_OLD_RT_SIGFRAME_UCONTEXT,
ARM_NEW_RT_SIGFRAME_UCONTEXT, ARM_NEW_SIGFRAME_MAGIC): Move stack
layout defines to arch/arm-linux.h.
(arm_linux_sigreturn_next_pc_offset): Move to arch/arm-linux.c.
(arm_linux_software_single_step): Adjust for arm_get_next_pcs
implementation.
* arm-tdep.c: Include arch/arm-get-next-pcs.h.
(arm_get_next_pcs_ops): New struct.
(submask): Move macro to arm.h.
(bit): Likewise.
(bits): Likewise.
(sbits): Likewise.
(BranchDest): Likewise.
(thumb_instruction_changes_pc): Move to arm.c
(thumb2_instruction_changes_pc): Likewise.
(arm_instruction_changes_pc): Likewise.
(shifted_reg_val): Likewise.
(thumb_advance_itstate): Likewise.
(thumb_get_next_pc_raw): Move to arm-get-next-pcs.c.
(arm_get_next_pc_raw): Likewise.
(arm_get_next_pc): Likewise.
(thumb_deal_with_atomic_sequence_raw): Likewise.
(arm_deal_with_atomic_sequence_raw): Likewise.
(arm_deal_with_atomic_sequence): Likewise.
(arm_get_next_pcs_read_memory_unsigned_integer): New function.
(arm_get_next_pcs_addr_bits_remove): Likewise.
(arm_get_next_pcs_syscall_next_pc): Likewise.
(arm_get_next_pcs_is_thumb): Likewise.
(arm_software_single_step): Adjust for arm_get_next_pcs
implementation.
* arm-tdep.h: (arm_get_next_pc): Remove declaration.
(arm_get_next_pcs_read_memory_unsigned_integer):
New declaration.
(arm_get_next_pcs_addr_bits_remove): Likewise.
(arm_get_next_pcs_syscall_next_pc): Likewise.
(arm_get_next_pcs_is_thumb): Likewise.
(arm_deal_with_atomic_sequence: Remove declaration.
* common/gdb_vecs.h: Add CORE_ADDR vector definition.
* configure.tgt (aarch64*-*-linux): Add arm-get-next-pcs.o,
arm-linux.o.
(arm*-wince-pe): Add arm-get-next-pcs.o.
(arm*-*-linux*): Add arm-get-next-pcs.o, arm-linux.o,
arm-get-next-pcs.o
(arm*-*-netbsd*,arm*-*-knetbsd*-gnu): Add arm-get-next-pcs.o.
(arm*-*-openbsd*): Likewise.
(arm*-*-symbianelf*): Likewise.
(arm*-*-*): Likewise.
* symtab.h: Move CORE_ADDR vector definition to gdb_vecs.h.
gdb/gdbserver/ChangeLog:
* Makefile.in (SFILES): Append arch/arm-linux.c,
arch/arm-get-next-pcs.c.
(arm-linux.o): New rule.
(arm-get-next-pcs.o): New rule.
* configure.srv (arm*-*-linux*): Add arm-get-next-pcs.o,
arm-linux.o.
* linux-aarch32-low.c (arm_abi_breakpoint): Remove macro. Moved
to linux-aarch32-low.c.
(arm_eabi_breakpoint, arm_breakpoint): Likewise.
(arm_breakpoint_len, thumb_breakpoint): Likewise.
(thumb_breakpoint_len, thumb2_breakpoint): Likewise.
(thumb2_breakpoint_len): Likewise.
(arm_is_thumb_mode): Make non-static.
* linux-aarch32-low.h (arm_abi_breakpoint): New macro. Moved
from linux-aarch32-low.c.
(arm_eabi_breakpoint, arm_breakpoint): Likewise.
(arm_breakpoint_len, thumb_breakpoint): Likewise.
(thumb_breakpoint_len, thumb2_breakpoint): Likewise.
(thumb2_breakpoint_len): Likewise.
(arm_is_thumb_mode): New declaration.
* linux-arm-low.c: Include arch/arm-linux.h
aarch/arm-get-next-pcs.h, sys/syscall.h.
(get_next_pcs_ops): New struct.
(get_next_pcs_addr_bits_remove): New function.
(get_next_pcs_is_thumb): New function.
(get_next_pcs_read_memory_unsigned_integer): Likewise.
(arm_sigreturn_next_pc): Likewise.
(get_next_pcs_syscall_next_pc): Likewise.
(arm_gdbserver_get_next_pcs): Likewise.
(struct linux_target_ops) <arm_gdbserver_get_next_pcs>:
Initialize.
* linux-low.h: Move CORE_ADDR vector definition to gdb_vecs.h.
* server.h: Include gdb_vecs.h.
Yao Qi
Joel Brobecker
Antoine Tremblay