From: Yao Qi <qiyaoltc@gmail.com>
To: Antoine Tremblay <antoine.tremblay@ericsson.com>
Cc: Yao Qi <qiyaoltc@gmail.com>, Pedro Alves <palves@redhat.com>,
<gdb-patches@sourceware.org>
Subject: Re: [PATCH v7.1] Support software single step on ARM in GDBServer.
Date: Fri, 11 Dec 2015 15:38:00 -0000 [thread overview]
Message-ID: <86twnpov11.fsf@gmail.com> (raw)
In-Reply-To: <566AE65E.5080209@ericsson.com> (Antoine Tremblay's message of "Fri, 11 Dec 2015 10:06:06 -0500")
Antoine Tremblay <antoine.tremblay@ericsson.com> writes:
>
> I'm not sure a macro is a good thing, it often makes the code harder
> to parse for ides/emacs etc...
Why macro is bad?
>
> And I don't think shortening the lines is a good justification in
> general for a macro.
It is! Supposing we have a macro like this ...
#define ARM_READ_UINT(MEMADDR, LEN, BYTE_ORDER) \
self->ops->read_memory_unsigned_integer ((MEMADDR), (LEN), (BYTE_ORDER))
>
> How about I use a function pointer variable like :
>
> ULONGEST (*read_memory_uint) (CORE_ADDR memaddr, int len, int byte_order);
>
> read_memory_uint = self->ops->read_memory_unsigned_integer;
>
> That would be already 23 shorter.
>
>>> + loc += 2;
>>> + if (!((insn1 & 0xfff0) == 0xe850
>>> + || ((insn1 & 0xfff0) == 0xe8d0 && (insn2 & 0x00c0) == 0x0040)))
>>> + return NULL;
>>> +
>>> + /* Assume that no atomic sequence is longer than "atomic_sequence_length"
>>> + instructions. */
>>> + for (insn_count = 0; insn_count < atomic_sequence_length; ++insn_count)
>>> + {
>>> + insn1
>>> + = self->ops->read_memory_unsigned_integer (loc, 2,byte_order_for_code);
>>> + loc += 2;
>>> +
>>> + if (thumb_insn_size (insn1) != 4)
>>> + {
>>> + /* Assume that there is at most one conditional branch in the
>>> + atomic sequence. If a conditional branch is found, put a
>>> + breakpoint in its destination address. */
>>> + if ((insn1 & 0xf000) == 0xd000 && bits (insn1, 8, 11) != 0x0f)
>>> + {
>>> + if (last_breakpoint > 0)
>>> + return NULL; /* More than one conditional branch found,
>>> + fallback to the standard code. */
>>> +
>>> + breaks[1] = loc + 2 + (sbits (insn1, 0, 7) << 1);
>>> + last_breakpoint++;
>>> + }
>>> +
>>> + /* We do not support atomic sequences that use any *other*
>>> + instructions but conditional branches to change the PC.
>>> + Fall back to standard code to avoid losing control of
>>> + execution. */
>>> + else if (thumb_instruction_changes_pc (insn1))
>>> + return NULL;
>>> + }
>>> + else
>>> + {
>>> + insn2 = self->ops->read_memory_unsigned_integer
>>> + (loc, 2, byte_order_for_code);
>>
>> Format looks wrong, multiple instances of this problem in the patch.
>>
>
> Yes actually I was not sure about that and discussed this with Pedro
> and he agreed this was ok. That's why I went with that.
>
> At some point when you have
> if
> if
> if
> long_function_name (long variable,
>
> And that does not fit you could have
>
> long_function_name (
> long variable, ... )
>
> or long_function_name
> (long variable, ...)
>
> or ?
>
... then, this problem doesn't exist at all. Isn't it better below?
insn2 = ARM_READ_UINT (loc, 2, byte_order_for_code);
--
Yao (齐尧)
next prev parent reply other threads:[~2015-12-11 15:38 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-08 14:07 [PATCH v7 0/8] Support software single step and conditional breakpoints " Antoine Tremblay
2015-12-08 14:07 ` [PATCH v7 4/8] Refactor arm_software_single_step to use regcache Antoine Tremblay
2015-12-11 11:37 ` Yao Qi
2015-12-11 12:41 ` Antoine Tremblay
2015-12-08 14:07 ` [PATCH v7 3/8] Use xml-syscall to compare syscall numbers in arm_linux_sigreturn_return-addr Antoine Tremblay
2015-12-11 11:29 ` Yao Qi
2015-12-11 11:59 ` Pedro Alves
2015-12-11 12:02 ` Yao Qi
2015-12-11 12:05 ` Pedro Alves
2015-12-11 12:31 ` Antoine Tremblay
2015-12-11 12:47 ` Pedro Alves
2015-12-11 13:04 ` Antoine Tremblay
2015-12-11 13:20 ` Pedro Alves
2015-12-11 13:25 ` Antoine Tremblay
2015-12-15 12:46 ` Antoine Tremblay
2015-12-16 15:59 ` Pedro Alves
2015-12-16 16:36 ` Yao Qi
2015-12-16 16:37 ` Antoine Tremblay
2015-12-11 12:29 ` Antoine Tremblay
2015-12-16 15:59 ` Pedro Alves
2015-12-16 16:05 ` Antoine Tremblay
2015-12-16 16:24 ` [PATCH v7.1 " Antoine Tremblay
2015-12-17 10:09 ` Yao Qi
2015-12-17 10:17 ` Pedro Alves
2015-12-17 12:51 ` Antoine Tremblay
2015-12-17 13:25 ` Yao Qi
2015-12-17 13:36 ` Antoine Tremblay
2015-12-08 14:07 ` [PATCH v7 2/8] Share some ARM target dependent code from GDB with GDBServer Antoine Tremblay
2015-12-08 14:07 ` [PATCH v7 5/8] Share regcache function regcache_raw_read_unsigned Antoine Tremblay
2015-12-08 14:07 ` [PATCH v7 1/8] Replace breakpoint_reinsert_addr by get_next_pcs operation in GDBServer Antoine Tremblay
2015-12-08 14:08 ` [PATCH v7 7/8] Enable software single stepping for while-stepping actions " Antoine Tremblay
2015-12-08 14:08 ` [PATCH v7 6/8] Support software single step on ARM " Antoine Tremblay
2015-12-09 20:09 ` [PATCH v7.1] " Antoine Tremblay
2015-12-11 13:28 ` Yao Qi
2015-12-11 13:36 ` Antoine Tremblay
2015-12-11 13:41 ` Antoine Tremblay
2015-12-11 14:45 ` Yao Qi
2015-12-11 14:43 ` Yao Qi
2015-12-11 15:06 ` Antoine Tremblay
2015-12-11 15:26 ` Antoine Tremblay
2015-12-11 15:38 ` Yao Qi [this message]
2015-12-11 16:11 ` Antoine Tremblay
2015-12-11 16:26 ` [PATCH v7.2] " Antoine Tremblay
2015-12-11 17:28 ` Yao Qi
2015-12-11 17:52 ` Antoine Tremblay
2015-12-08 14:08 ` [PATCH v7 8/8] Enable conditional breakpoints for targets that support software single step " Antoine Tremblay
2015-12-10 15:59 ` [PATCH v7 0/8] Support software single step and conditional breakpoints on ARM " Yao Qi
2015-12-10 16:02 ` Antoine Tremblay
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