Re: [PATCH] Fix regression on aarch64-linux gdbserver

[Mark Wielaard <mark@klomp.org>]

[-- Attachment #1: Type: text/plain, Size: 2261 bytes --]

Hi,

On Mon, Apr 22, 2024 at 07:51:49AM -0600, Tom Tromey wrote:
> diff --git a/gdbserver/linux-aarch64-low.cc b/gdbserver/linux-aarch64-low.cc
> index 5df67fccd08..da5c1fd0629 100644
> --- a/gdbserver/linux-aarch64-low.cc
> +++ b/gdbserver/linux-aarch64-low.cc
> @@ -576,41 +576,9 @@ aarch64_target::low_stopped_data_address ()
>  
>    /* Check if the address matches any watched address.  */
>    state = aarch64_get_debug_reg_state (pid_of (current_thread));
> -  for (i = aarch64_num_wp_regs - 1; i >= 0; --i)
> -    {
> -      const unsigned int offset
> -	= aarch64_watchpoint_offset (state->dr_ctrl_wp[i]);
> -      const unsigned int len = aarch64_watchpoint_length (state->dr_ctrl_wp[i]);
> -      const CORE_ADDR addr_watch = state->dr_addr_wp[i] + offset;
> -      const CORE_ADDR addr_watch_aligned = align_down (state->dr_addr_wp[i], 8);
> -      const CORE_ADDR addr_orig = state->dr_addr_orig_wp[i];
> -
> -      if (state->dr_ref_count_wp[i]
> -	  && DR_CONTROL_ENABLED (state->dr_ctrl_wp[i])
> -	  && addr_trap >= addr_watch_aligned
> -	  && addr_trap < addr_watch + len)
> -	{
> -	  /* ADDR_TRAP reports the first address of the memory range
> -	     accessed by the CPU, regardless of what was the memory
> -	     range watched.  Thus, a large CPU access that straddles
> -	     the ADDR_WATCH..ADDR_WATCH+LEN range may result in an
> -	     ADDR_TRAP that is lower than the
> -	     ADDR_WATCH..ADDR_WATCH+LEN range.  E.g.:
> -
> -	     addr: |   4   |   5   |   6   |   7   |   8   |
> -				   |---- range watched ----|
> -		   |----------- range accessed ------------|
> -
> -	     In this case, ADDR_TRAP will be 4.
> -
> -	     To match a watchpoint known to GDB core, we must never
> -	     report *ADDR_P outside of any ADDR_WATCH..ADDR_WATCH+LEN
> -	     range.  ADDR_WATCH <= ADDR_TRAP < ADDR_ORIG is a false
> -	     positive on kernels older than 4.10.  See PR
> -	     external/20207.  */
> -	  return addr_orig;
> -	}
> -    }
> +  CORE_ADDR result;
> +  if (aarch64_stopped_data_address (state, addr_trap, &result))
> +    return result;
>  
>    return (CORE_ADDR) 0;
>  }

This broke the build on the gdb-fedora-arm64 buildbot:
https://builder.sourceware.org/buildbot/#/builders/181/builds/6402

Fix attached.

Cheers,

Mark

[-- Attachment #2: 0001-Fix-gdbserver-linux-aarch64-low.cc-build.patch --]
[-- Type: text/plain, Size: 1422 bytes --]

From f27b8de72a42650a948fef0adc17e82517c14c2a Mon Sep 17 00:00:00 2001
From: Mark Wielaard <mark@klomp.org>
Date: Thu, 2 May 2024 23:58:20 +0200
Subject: [PATCH] Fix gdbserver/linux-aarch64-low.cc build
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Commit 0ee25f97d21e ("Fix regression on aarch64-linux gdbserver")
removed the last use of i in gdbserver/linux-aarch64-low.cc
(aarch64_target::low_stopped_data_address). Breaking the build on
aarch64 with:

gdbserver/linux-aarch64-low.cc: In member function ‘virtual CORE_ADDR aarch64_target::low_stopped_data_address()’:
gdbserver/linux-aarch64-low.cc:557:12: error: unused variable ‘i’ [-Werror=unused-variable]
  557 |   int pid, i;
      |            ^
cc1plus: all warnings being treated as errors

Fix this by removing the variable i completely.

Fixes: 0ee25f97d21e ("Fix regression on aarch64-linux gdbserver")
---
 gdbserver/linux-aarch64-low.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gdbserver/linux-aarch64-low.cc b/gdbserver/linux-aarch64-low.cc
index da5c1fd06298..eb30c31f8f80 100644
--- a/gdbserver/linux-aarch64-low.cc
+++ b/gdbserver/linux-aarch64-low.cc
@@ -554,7 +554,7 @@ CORE_ADDR
 aarch64_target::low_stopped_data_address ()
 {
   siginfo_t siginfo;
-  int pid, i;
+  int pid;
   struct aarch64_debug_reg_state *state;
 
   pid = lwpid_of (current_thread);
-- 
2.39.3