[2/2] gdb/amdgpu: add precise-memory support

  The amd-dbgapi library exposes a setting called "memory precision" for
AMD GPUs [1].  Here's a copy of the description of the setting:

    The AMD GPU can overlap the execution of memory instructions with other
    instructions.  This can result in a wave stopping due to a memory violation
    or hardware data watchpoint hit with a program counter beyond the
    instruction that caused the wave to stop.

    Some architectures allow the hardware to be configured to always wait for
    memory operations to complete before continuing.  This will result in the
    wave stopping at the instruction immediately after the one that caused the
    stop event.  Enabling this mode can make execution of waves significantly
    slower.

Expose this option through a new "amdgpu precise-memory" setting.

The precise memory setting is per inferior.  The setting is transferred
from one inferior to another when using the clone-inferior command, or
when a new inferior is created following an exec or a fork.

It can be set before starting the inferior, in which case GDB will
attempt to apply what the user wants when attaching amd-dbgapi.  If the
user has requested to enable precise memory, but it can't be enabled
(not all hardware supports it), GDB prints a warning.

If precise memory is disabled, GDB prints a warning when hitting a
memory exception (translated into GDB_SIGNAL_SEGV or GDB_SIGNAL_BUS),
saying that the stop location may not be precise.

Note that the precise memory setting also affects memory watchpoint
reporting, but the watchpoint support for AMD GPUs hasn't been
upstreamed to GDB yet.  When we do upstream watchpoint support, GDB will
produce a similar warning message when stopping due to a watchpoint if
precise memory is disabled.

Add a handful of tests.  Add a util proc
"hip_device_supports_precise_memory", which indicates if the device used
for testing supports that feature.  To implement it, also add a new
"hcc_amdgpu_target" proc, to return the architecture of the device used
for testing.

[1] https://github.com/ROCm-Developer-Tools/ROCdbgapi/blob/687374258a27b5aab1309a7e8ded719e2f1ed3b1/include/amd-dbgapi.h.in#L6300-L6317

Change-Id: Ife1a99c0e960513da375ced8f8afaf8e47a61b3f
---
 gdb/amd-dbgapi-target.c                       | 199 +++++++++++++++++-
 gdb/doc/gdb.texinfo                           |  43 ++++
 gdb/testsuite/gdb.rocm/precise-memory-exec.c  |  44 ++++
 .../gdb.rocm/precise-memory-exec.exp          |  62 ++++++
 gdb/testsuite/gdb.rocm/precise-memory-fork.c  |  41 ++++
 .../gdb.rocm/precise-memory-fork.exp          |  54 +++++
 .../precise-memory-multi-inferiors.exp        |  87 ++++++++
 .../precise-memory-warning-sigsegv.cpp        |  33 +++
 .../precise-memory-warning-sigsegv.exp        |  49 +++++
 gdb/testsuite/gdb.rocm/precise-memory.cpp     |  32 +++
 gdb/testsuite/gdb.rocm/precise-memory.exp     |  57 +++++
 gdb/testsuite/lib/rocm.exp                    |  59 ++++++
 12 files changed, 755 insertions(+), 5 deletions(-)
 create mode 100644 gdb/testsuite/gdb.rocm/precise-memory-exec.c
 create mode 100644 gdb/testsuite/gdb.rocm/precise-memory-exec.exp
 create mode 100644 gdb/testsuite/gdb.rocm/precise-memory-fork.c
 create mode 100644 gdb/testsuite/gdb.rocm/precise-memory-fork.exp
 create mode 100644 gdb/testsuite/gdb.rocm/precise-memory-multi-inferiors.exp
 create mode 100644 gdb/testsuite/gdb.rocm/precise-memory-warning-sigsegv.cpp
 create mode 100644 gdb/testsuite/gdb.rocm/precise-memory-warning-sigsegv.exp
 create mode 100644 gdb/testsuite/gdb.rocm/precise-memory.cpp
 create mode 100644 gdb/testsuite/gdb.rocm/precise-memory.exp
  

Hi Simon,

Thanks for doing this.  I have a couple of remarks inlined in the patch.

Best,
Lancelot.

On Wed, Sep 13, 2023 at 11:28:38AM -0400, Simon Marchi via Gdb-patches wrote:
> The amd-dbgapi library exposes a setting called "memory precision" for
> AMD GPUs [1].  Here's a copy of the description of the setting:
> 
>     The AMD GPU can overlap the execution of memory instructions with other
>     instructions.  This can result in a wave stopping due to a memory violation
>     or hardware data watchpoint hit with a program counter beyond the
>     instruction that caused the wave to stop.
> 
>     Some architectures allow the hardware to be configured to always wait for
>     memory operations to complete before continuing.  This will result in the
>     wave stopping at the instruction immediately after the one that caused the
>     stop event.  Enabling this mode can make execution of waves significantly
>     slower.
> 
> Expose this option through a new "amdgpu precise-memory" setting.
> 
> The precise memory setting is per inferior.  The setting is transferred
> from one inferior to another when using the clone-inferior command, or
> when a new inferior is created following an exec or a fork.
> 
> It can be set before starting the inferior, in which case GDB will
> attempt to apply what the user wants when attaching amd-dbgapi.  If the
> user has requested to enable precise memory, but it can't be enabled
> (not all hardware supports it), GDB prints a warning.
> 
> If precise memory is disabled, GDB prints a warning when hitting a
> memory exception (translated into GDB_SIGNAL_SEGV or GDB_SIGNAL_BUS),
> saying that the stop location may not be precise.
> 
> Note that the precise memory setting also affects memory watchpoint
> reporting, but the watchpoint support for AMD GPUs hasn't been
> upstreamed to GDB yet.  When we do upstream watchpoint support, GDB will
> produce a similar warning message when stopping due to a watchpoint if
> precise memory is disabled.
> 
> Add a handful of tests.  Add a util proc
> "hip_device_supports_precise_memory", which indicates if the device used
> for testing supports that feature.  To implement it, also add a new
> "hcc_amdgpu_target" proc, to return the architecture of the device used
> for testing.
> 
> [1] https://github.com/ROCm-Developer-Tools/ROCdbgapi/blob/687374258a27b5aab1309a7e8ded719e2f1ed3b1/include/amd-dbgapi.h.in#L6300-L6317
> 
> Change-Id: Ife1a99c0e960513da375ced8f8afaf8e47a61b3f
> ---
>  gdb/amd-dbgapi-target.c                       | 199 +++++++++++++++++-
>  gdb/doc/gdb.texinfo                           |  43 ++++
>  gdb/testsuite/gdb.rocm/precise-memory-exec.c  |  44 ++++
>  .../gdb.rocm/precise-memory-exec.exp          |  62 ++++++
>  gdb/testsuite/gdb.rocm/precise-memory-fork.c  |  41 ++++
>  .../gdb.rocm/precise-memory-fork.exp          |  54 +++++
>  .../precise-memory-multi-inferiors.exp        |  87 ++++++++
>  .../precise-memory-warning-sigsegv.cpp        |  33 +++
>  .../precise-memory-warning-sigsegv.exp        |  49 +++++
>  gdb/testsuite/gdb.rocm/precise-memory.cpp     |  32 +++
>  gdb/testsuite/gdb.rocm/precise-memory.exp     |  57 +++++
>  gdb/testsuite/lib/rocm.exp                    |  59 ++++++
>  12 files changed, 755 insertions(+), 5 deletions(-)
>  create mode 100644 gdb/testsuite/gdb.rocm/precise-memory-exec.c
>  create mode 100644 gdb/testsuite/gdb.rocm/precise-memory-exec.exp
>  create mode 100644 gdb/testsuite/gdb.rocm/precise-memory-fork.c
>  create mode 100644 gdb/testsuite/gdb.rocm/precise-memory-fork.exp
>  create mode 100644 gdb/testsuite/gdb.rocm/precise-memory-multi-inferiors.exp
>  create mode 100644 gdb/testsuite/gdb.rocm/precise-memory-warning-sigsegv.cpp
>  create mode 100644 gdb/testsuite/gdb.rocm/precise-memory-warning-sigsegv.exp
>  create mode 100644 gdb/testsuite/gdb.rocm/precise-memory.cpp
>  create mode 100644 gdb/testsuite/gdb.rocm/precise-memory.exp
> 
> diff --git a/gdb/amd-dbgapi-target.c b/gdb/amd-dbgapi-target.c
> index 22c269b7992c..cfb935df1163 100644
> --- a/gdb/amd-dbgapi-target.c
> +++ b/gdb/amd-dbgapi-target.c
> @@ -23,6 +23,7 @@
>  #include "amdgpu-tdep.h"
>  #include "async-event.h"
>  #include "cli/cli-cmds.h"
> +#include "cli/cli-decode.h"
>  #include "cli/cli-style.h"
>  #include "inf-loop.h"
>  #include "inferior.h"
> @@ -139,6 +140,17 @@ struct amd_dbgapi_inferior_info
>       Initialized to true, since that's the default in amd-dbgapi too.  */
>    bool forward_progress_required = true;
>  
> +  struct
> +  {
> +    /* Whether precise memory reporting is requested.  */
> +    bool requested = false;
> +
> +    /* Whether precise memory was requested and successfully enabled by
> +       dbgapi (it may not be available for the current hardware, for
> +       instance).  */
> +    bool enabled = false;
> +  } precise_memory;
> +
>    std::unordered_map<decltype (amd_dbgapi_breakpoint_id_t::handle),
>  		     struct breakpoint *>
>      breakpoint_map;
> @@ -1326,6 +1338,36 @@ amd_dbgapi_target::stopped_by_hw_breakpoint ()
>    return false;
>  }
>  
> +/* Set the process's memory access reporting precision.
> +
> +   The precision can be ::AMD_DBGAPI_MEMORY_PRECISION_PRECISE (waves wait for
> +   memory instructions to complete before executing further instructions), or
> +   ::AMD_DBGAPI_MEMORY_PRECISION_NONE (memory instructions execute normally).
> +
> +   Returns true if the precision is supported by the architecture of all agents
> +   in the process, or false if at least one agent does not support the
> +   requested precision.
> +
> +   An error is thrown if setting the precision results in a status other than
> +   ::AMD_DBGAPI_STATUS_SUCCESS or ::AMD_DBGAPI_STATUS_ERROR_NOT_SUPPORTED.  */
> +

Would it be simpler if this helper function received a bool parameter
instead of the amd_dbgapi_memory_precision_t one?  This could avoid
repeating this

     amd_dbgapi_memory_precision_t memory_precision
       = (info->precise_memory.requested
          ? AMD_DBGAPI_MEMORY_PRECISION_PRECISE
          : AMD_DBGAPI_MEMORY_PRECISION_NONE);

before calling it.

> +static bool
> +set_process_memory_precision (amd_dbgapi_process_id_t process_id,
> +			      amd_dbgapi_memory_precision_t precision)
> +{
> +  amd_dbgapi_status_t status
> +    = amd_dbgapi_set_memory_precision (process_id, precision);
> +
> +  if (status == AMD_DBGAPI_STATUS_ERROR_NOT_SUPPORTED)
> +    return false;
> +
> +  if (status != AMD_DBGAPI_STATUS_SUCCESS)
> +    error (_("amd_dbgapi_set_memory_precision failed (%s)"),
> +	   get_status_string (status));
> +
> +  return true;
> +}
> +
>  /* Make the amd-dbgapi library attach to the process behind INF.
>  
>     Note that this is unrelated to the "attach" GDB concept / command.
> @@ -1399,6 +1441,16 @@ attach_amd_dbgapi (inferior *inf)
>    amd_dbgapi_debug_printf ("process_id = %" PRIu64 ", notifier fd = %d",
>  			   info->process_id.handle, info->notifier);
>  
> +  amd_dbgapi_memory_precision_t memory_precision
> +    = (info->precise_memory.requested
> +       ? AMD_DBGAPI_MEMORY_PRECISION_PRECISE
> +       : AMD_DBGAPI_MEMORY_PRECISION_NONE);
> +  if (set_process_memory_precision (info->process_id, memory_precision))
> +    info->precise_memory.enabled = info->precise_memory.requested;
> +  else
> +    warning
> +      (_("AMDGPU precise memory access reporting could not be enabled."));
> +
>    /* If GDB is attaching to a process that has the runtime loaded, there will
>       already be a "runtime loaded" event available.  Consume it and push the
>       target.  */
> @@ -1443,8 +1495,10 @@ detach_amd_dbgapi (inferior *inf)
>    for (auto &&value : info->breakpoint_map)
>      delete_breakpoint (value.second);
>  
> -  /* Reset the amd_dbgapi_inferior_info.  */
> +  /* Reset the amd_dbgapi_inferior_info, except for precise_memory_mode.  */
> +  bool precise_memory_requested = info->precise_memory.requested;
>    *info = amd_dbgapi_inferior_info (inf);
> +  info->precise_memory.requested = precise_memory_requested;
>  
>    maybe_reset_amd_dbgapi ();
>  }
> @@ -1668,6 +1722,22 @@ amd_dbgapi_target_inferior_created (inferior *inf)
>    attach_amd_dbgapi (inf);
>  }
>  
> +/* Callback called when an inferior is cloned.  */
> +
> +static void
> +amd_dbgapi_target_inferior_cloned (inferior *original_inferior,
> +				   inferior *new_inferior)
> +{
> +  auto *orig_info = get_amd_dbgapi_inferior_info (original_inferior);
> +  auto *new_info = get_amd_dbgapi_inferior_info (new_inferior);
> +
> +  /* At this point, the process is not started.  Therefore it is sufficient to
> +     copy the precise memory request, it will be applied when the process
> +     starts.  */
> +  gdb_assert (new_info->process_id == AMD_DBGAPI_PROCESS_NONE);
> +  new_info->precise_memory.requested = orig_info->precise_memory.requested;
> +}
> +
>  /* inferior_execd observer.  */
>  
>  static void
> @@ -1677,6 +1747,13 @@ amd_dbgapi_inferior_execd (inferior *exec_inf, inferior *follow_inf)
>       attached to the old process image, so we need to detach and re-attach to
>       the new process image.  */
>    detach_amd_dbgapi (exec_inf);
> +
> +  /* If using "follow-exec-mode new", carry over the precise-memory setting
> +     to the new inferior (otherwise, FOLLOW_INF and ORIG_INF point to the same
> +     inferior, so this is a no-op).  */
> +  get_amd_dbgapi_inferior_info (follow_inf)->precise_memory.requested
> +    = get_amd_dbgapi_inferior_info (exec_inf)->precise_memory.requested;
> +
>    attach_amd_dbgapi (follow_inf);
>  }
>  
> @@ -1686,11 +1763,22 @@ static void
>  amd_dbgapi_inferior_forked (inferior *parent_inf, inferior *child_inf,
>  			    target_waitkind fork_kind)
>  {
> -  if (child_inf != nullptr  && fork_kind != TARGET_WAITKIND_VFORKED)
> +  if (child_inf != nullptr)
>      {
> -      scoped_restore_current_thread restore_thread;
> -      switch_to_thread (*child_inf->threads ().begin ());
> -      attach_amd_dbgapi (child_inf);
> +      /* Copy precise-memory requested value from parent to child.  */
> +      amd_dbgapi_inferior_info *parent_info
> +	= get_amd_dbgapi_inferior_info (parent_inf);
> +      amd_dbgapi_inferior_info *child_info
> +	= get_amd_dbgapi_inferior_info (child_inf);
> +      child_info->precise_memory.requested
> +	= parent_info->precise_memory.requested;
> +
> +      if (fork_kind != TARGET_WAITKIND_VFORKED)
> +	{
> +	  scoped_restore_current_thread restore_thread;
> +	  switch_to_thread (*child_inf->threads ().begin ());
> +	  attach_amd_dbgapi (child_inf);
> +	}
>      }
>  }
>  
> @@ -1785,6 +1873,29 @@ amd_dbgapi_remove_breakpoint_callback
>    return AMD_DBGAPI_STATUS_SUCCESS;
>  }
>  
> +/* signal_received observer.  */
> +
> +static void
> +amd_dbgapi_target_signal_received (gdb_signal sig)
> +{
> +  amd_dbgapi_inferior_info *info
> +    = get_amd_dbgapi_inferior_info (current_inferior ());
> +
> +  if (info->process_id == AMD_DBGAPI_PROCESS_NONE)
> +    return;
> +
> +  if (!ptid_is_gpu (inferior_thread ()->ptid))
> +    return;
> +
> +  if (sig != GDB_SIGNAL_SEGV && sig != GDB_SIGNAL_BUS)
> +    return;
> +
> +  if (!info->precise_memory.enabled)
> +    gdb_printf ("\

I think there should be a _() surrounding the string.

> +Warning: precise memory violation signal reporting is not enabled, reported\n\
> +location may not be accurate.  See \"show amdgpu precise-memory\".\n");
> +}
> +
>  /* Style for some kinds of messages.  */
>  
>  static cli_style_option fatal_error_style
> @@ -1853,6 +1964,62 @@ amd_dbgapi_target::close ()
>      delete_async_event_handler (&amd_dbgapi_async_event_handler);
>  }
>  
> +/* Callback for "show amdgpu precise-memory".  */
> +
> +static void
> +show_precise_memory_mode (struct ui_file *file, int from_tty,
> +			  struct cmd_list_element *c, const char *value)
> +{
> +  amd_dbgapi_inferior_info *info
> +    = get_amd_dbgapi_inferior_info (current_inferior ());
> +
> +  gdb_printf (file,
> +	      _("AMDGPU precise memory access reporting is %s "
> +		"(currently %s).\n"),
> +	      info->precise_memory.requested ? "on" : "off",
> +	      info->precise_memory.enabled ? "enabled" : "disabled");
> +}
> +
> +/* Callback for "set amdgpu precise-memory".  */
> +
> +static void
> +set_precise_memory_mode (bool value)
> +{
> +  amd_dbgapi_inferior_info *info
> +    = get_amd_dbgapi_inferior_info (current_inferior ());
> +
> +  info->precise_memory.requested = value;
> +
> +  if (info->process_id != AMD_DBGAPI_PROCESS_NONE)
> +    {
> +      amd_dbgapi_memory_precision_t memory_precision
> +	= (info->precise_memory.requested
> +	   ? AMD_DBGAPI_MEMORY_PRECISION_PRECISE
> +	   : AMD_DBGAPI_MEMORY_PRECISION_NONE);
> +
> +      if (set_process_memory_precision (info->process_id, memory_precision))
> +	info->precise_memory.enabled = info->precise_memory.requested;
> +      else
> +	warning
> +	  (_("AMDGPU precise memory access reporting could not be enabled."));
> +    }
> +}
> +
> +/* Return whether precise-memory is requested for the current inferior.  */
> +
> +static bool
> +get_precise_memory_mode ()
> +{
> +  amd_dbgapi_inferior_info *info
> +    = get_amd_dbgapi_inferior_info (current_inferior ());
> +
> +  return info->precise_memory.requested;
> +}
> +
> +/* List of set/show amdgpu commands.  */
> +struct cmd_list_element *set_amdgpu_list;
> +struct cmd_list_element *show_amdgpu_list;
> +
>  /* List of set/show debug amd-dbgapi-lib commands.  */
>  struct cmd_list_element *set_debug_amd_dbgapi_lib_list;
>  struct cmd_list_element *show_debug_amd_dbgapi_lib_list;
> @@ -1960,6 +2127,10 @@ _initialize_amd_dbgapi_target ()
>    amd_dbgapi_set_log_level (get_debug_amd_dbgapi_lib_log_level ());
>  
>    /* Install observers.  */
> +  gdb::observers::inferior_cloned.attach (amd_dbgapi_target_inferior_cloned,
> +					  "amd-dbgapi");
> +  gdb::observers::signal_received.attach (amd_dbgapi_target_signal_received,
> +					  "amd-dbgapi");
>    gdb::observers::inferior_created.attach
>      (amd_dbgapi_target_inferior_created,
>       amd_dbgapi_target_inferior_created_observer_token, "amd-dbgapi");
> @@ -1968,6 +2139,24 @@ _initialize_amd_dbgapi_target ()
>    gdb::observers::inferior_exit.attach (amd_dbgapi_inferior_exited, "amd-dbgapi");
>    gdb::observers::inferior_pre_detach.attach (amd_dbgapi_inferior_pre_detach, "amd-dbgapi");
>  
> +  add_basic_prefix_cmd ("amdgpu", no_class,
> +			_("Generic command for setting amdgpu flags."),
> +			&set_amdgpu_list, 0, &setlist);
> +
> +  add_show_prefix_cmd ("amdgpu", no_class,
> +		       _("Generic command for showing amdgpu flags."),
> +		       &show_amdgpu_list, 0, &showlist);
> +
> +  add_setshow_boolean_cmd ("precise-memory", no_class,
> +			   _("Set precise-memory mode."),
> +			   _("Show precise-memory mode."), _("\
> +If on, precise memory reporting is enabled if/when the inferior is running.\n\
> +If off (default), precise memory reporting is disabled."),
> +			   set_precise_memory_mode,
> +			   get_precise_memory_mode,
> +			   show_precise_memory_mode,
> +			   &set_amdgpu_list, &show_amdgpu_list);
> +
>    add_basic_prefix_cmd ("amd-dbgapi-lib", no_class,
>  			_("Generic command for setting amd-dbgapi library "
>  			  "debugging flags."),
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index 9b7e06f31566..fa91d72695e7 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -26794,6 +26794,49 @@ either not mapped or accessed with incompatible permissions.
>  If a single instruction raises more than one signal, they will be
>  reported one at a time each time the wavefront is continued.
>  
> +@subsubsection @acronym{AMD GPU} Memory Violation Reporting
> +
> +A wavefront can report memory violation events.  However, the program
> +location at which they are reported may be after the machine instruction
> +that caused them.  This can result in the reported source statement
> +being incorrect.  The following commands can be used to control this
> +behavior:
> +
> +@table @code
> +
> +@kindex set amdgpu precise-memory
> +@cindex AMD GPU precise memory event reporting
> +@item set amdgpu precise-memory @var{mode}
> +Controls how @acronym{AMD GPU} devices detect memory violations, where
> +@var{mode} can be:
> +
> +@table @code
> +
> +@item off
> +The program location may not be immediately after the instruction that
> +caused the memory violation.  This is the default.
> +
> +@item on
> +Requests that the program location will be immediately after the
> +instruction that caused a memory violation.  Enabling this mode may make
> +the @acronym{AMD GPU} device execution significantly slower as it has to
> +wait for each memory operation to complete before executing the next
> +instruction.
> +
> +@end table
> +
> +The @code{set amdgpu precise-memory} parameter is per-inferior.  When an
             ^
Isn't the parameter name just "amdgpu precise-memory"?

> +inferior forks or execs, or the user uses the @code{clone-inferior} command,
> +and an inferior is created as a result, the newly created inferior inherits
> +the parameter value of the original inferior.
> +
> +@kindex show amdgpu precise-memory
> +@cindex AMD GPU precise memory event reporting
> +@item show amdgpu precise-memory
> +Displays the currently requested AMD GPU precise memory setting.
> +
> +@end table
> +
>  @subsubsection @acronym{AMD GPU} Logging
>  
>  The @samp{set debug amd-dbgapi} command can be used
> diff --git a/gdb/testsuite/gdb.rocm/precise-memory-exec.c b/gdb/testsuite/gdb.rocm/precise-memory-exec.c
> new file mode 100644
> index 000000000000..f0659a63fc5a
> --- /dev/null
> +++ b/gdb/testsuite/gdb.rocm/precise-memory-exec.c
> @@ -0,0 +1,44 @@
> +/* Copyright 2021-2023 Free Software Foundation, Inc.
> +
> +   This file is part of GDB.
> +
> +   This program is free software; you can redistribute it and/or modify
> +   it under the terms of the GNU General Public License as published by
> +   the Free Software Foundation; either version 3 of the License, or
> +   (at your option) any later version.
> +
> +   This program is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +   GNU General Public License for more details.
> +
> +   You should have received a copy of the GNU General Public License
> +   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
> +
> +#include <unistd.h>
> +#include <stdlib.h>
> +#include <stdio.h>
> +
> +static void
> +second (void)
> +{
> +}
> +
> +int
> +main (int argc, char **argv)
> +{
> +  if (argc == 1)
> +    {
> +      /* First invocation */

Should the comment end with ".  "?

> +      int ret = execl (argv[0], argv[0], "Hello", NULL);
> +      perror ("exec");
> +      abort ();
> +    }
> +  else
> +    {
> +      /* Second invocation */

Here also.

> +      second ();
> +    }
> +
> +  return 0;
> +}
> diff --git a/gdb/testsuite/gdb.rocm/precise-memory-exec.exp b/gdb/testsuite/gdb.rocm/precise-memory-exec.exp
> new file mode 100644
> index 000000000000..26be6cf72146
> --- /dev/null
> +++ b/gdb/testsuite/gdb.rocm/precise-memory-exec.exp
> @@ -0,0 +1,62 @@
> +# Copyright 2021-2023 Free Software Foundation, Inc.
> +
> +# This file is part of GDB.
> +
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +
> +# Test that the "set amdgpu precise-memory" setting is inherited by an inferior
> +# created following an exec.
> +
> +load_lib rocm.exp
> +
> +require allow_hipcc_tests
> +
> +if { ![istarget "*-linux*"] } then {
> +    continue
> +}

Should this test be integrated in allow_hipcc_test?  This would avoid
having to repeat it in multiple testcases (and all testcases do not have
such guard).

Also, I'm not sure if there is any non-linux configuration which can
satisfy allow_hipcc_tests, which would make this test redundant.

> +
> +standard_testfile .c
> +
> +if {[build_executable "failed to prepare $testfile" $testfile $srcfile {debug}]} {
> +    return
> +}
> +
> +proc do_test { follow-exec-mode } {
> +    clean_restart $::binfile
> +
> +    with_rocm_gpu_lock {
> +	if ![runto_main] {
> +	    return
> +	}
> +
> +	# Set precise-memory on the inferior before exec.
> +	gdb_test "show amdgpu precise-memory" " is off.*" \
> +	    "show amdgpu precise-memory before set"
> +	gdb_test "set amdgpu precise-memory on"
> +	gdb_test "show amdgpu precise-memory" " is on.*" \
> +	    "show amdgpu precise-memory after set"
> +
> +	# Continue past exec.  The precise-memory setting should
> +	# be on.
> +	gdb_test_no_output "set follow-exec-mode ${follow-exec-mode}"
> +	gdb_test "break second"
> +	gdb_test "continue" "Breakpoint 1(\.$::decimal)?, main .*"
> +	gdb_test "show amdgpu precise-memory" " is on.*" \
> +	    "show amdgpu precise-memory after exec"
> +    }
> +}
> +
> +foreach_with_prefix follow-exec-mode {same new} {
> +    do_test ${follow-exec-mode}
> +}
> diff --git a/gdb/testsuite/gdb.rocm/precise-memory-fork.c b/gdb/testsuite/gdb.rocm/precise-memory-fork.c
> new file mode 100644
> index 000000000000..67ce09f2c3dc
> --- /dev/null
> +++ b/gdb/testsuite/gdb.rocm/precise-memory-fork.c
> @@ -0,0 +1,41 @@
> +/* Copyright 2021-2023 Free Software Foundation, Inc.
> +
> +   This file is part of GDB.
> +
> +   This program is free software; you can redistribute it and/or modify
> +   it under the terms of the GNU General Public License as published by
> +   the Free Software Foundation; either version 3 of the License, or
> +   (at your option) any later version.
> +
> +   This program is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +   GNU General Public License for more details.
> +
> +   You should have received a copy of the GNU General Public License
> +   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
> +
> +#include <unistd.h>
> +
> +static void
> +parent (void)
> +{
> +}
> +
> +static void
> +child (void)
> +{
> +}
> +
> +int
> +main (void)
> +{
> +  int pid = fork ();
> +
> +  if (pid != 0)
> +    parent ();
> +  else
> +    child ();
> +
> +  return 0;
> +}
> diff --git a/gdb/testsuite/gdb.rocm/precise-memory-fork.exp b/gdb/testsuite/gdb.rocm/precise-memory-fork.exp
> new file mode 100644
> index 000000000000..0dc88b89f8a7
> --- /dev/null
> +++ b/gdb/testsuite/gdb.rocm/precise-memory-fork.exp
> @@ -0,0 +1,54 @@
> +# Copyright 2021-2023 Free Software Foundation, Inc.
> +
> +# This file is part of GDB.
> +
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +
> +# Test that the "set amdgpu precise-memory" setting is inherited by a fork
> +# child.
> +
> +load_lib rocm.exp
> +
> +require allow_hipcc_tests
> +
> +if { ![istarget "*-linux*"] } then {
> +    continue
> +}

Same remark here.

> +
> +standard_testfile .c
> +
> +if {[prepare_for_testing "failed to prepare $testfile" $testfile $srcfile {debug}]} {
> +    return
> +}
> +
> +with_rocm_gpu_lock {
> +    if ![runto_main] {
> +	return
> +    }
> +
> +    # Set precise-memory on in the parent, before fork.
> +    gdb_test "show amdgpu precise-memory" " is off.*" \
> +	"show amdgpu precise-memory before set"
> +    gdb_test "set amdgpu precise-memory on"
> +    gdb_test "show amdgpu precise-memory" " is on.*" \
> +	"show amdgpu precise-memory after set"
> +
> +    # Continue past fork, following the child.  The precise-memory setting should
> +    # be on.
> +    gdb_test "set follow-fork-mode child"
> +    gdb_test "break child"
> +    gdb_test "continue" "Thread 2.1 .* hit Breakpoint .*"
> +    gdb_test "show amdgpu precise-memory" " is on.*" \
> +	"show amdgpu precise-memory after fork"
> +}
> diff --git a/gdb/testsuite/gdb.rocm/precise-memory-multi-inferiors.exp b/gdb/testsuite/gdb.rocm/precise-memory-multi-inferiors.exp
> new file mode 100644
> index 000000000000..9968b422b0ee
> --- /dev/null
> +++ b/gdb/testsuite/gdb.rocm/precise-memory-multi-inferiors.exp
> @@ -0,0 +1,87 @@
> +# Copyright 2021-2023 Free Software Foundation, Inc.
> +
> +# This file is part of GDB.
> +
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +
> +# Test that the "set amdgpu precise-memory" setting is per-inferior, and
> +# inherited by an inferior created using the clone-inferior command.
> +
> +load_lib rocm.exp
> +
> +require allow_hipcc_tests
> +
> +clean_restart
> +
> +set test_python [allow_python_tests]
> +
> +proc test_per_inferior { } {
> +    gdb_test "show amdgpu precise-memory" \
> +	"AMDGPU precise memory access reporting is off \\(currently disabled\\)." \
> +	"show initial value, inferior 1"
> +    if $::test_python {
> +	gdb_test "python print(gdb.parameter(\"amdgpu precise-memory\"))" \
> +	    "False" \
> +	    "show initial value using Python, inferior 1"
> +    }
> +    gdb_test_no_output "set amdgpu precise-memory" \
> +	"set on inferior 1"
> +    gdb_test "show amdgpu precise-memory" \
> +	"AMDGPU precise memory access reporting is on \\(currently disabled\\)." \
> +	"show new value, inferior 1"
> +    if $::test_python {
> +	gdb_test "python print(gdb.parameter(\"amdgpu precise-memory\"))" \
> +	    "True" \
> +	    "show new value using Python, inferior 1"
> +    }
> +
> +    gdb_test "add-inferior" "Added inferior 2"
> +    gdb_test "inferior 2" "Switching to inferior 2 .*"
> +
> +    gdb_test "show amdgpu precise-memory" \
> +	"AMDGPU precise memory access reporting is off \\(currently disabled\\)." \
> +	"show initial value, inferior 2"
> +    if $::test_python {
> +	gdb_test "python print(gdb.parameter(\"amdgpu precise-memory\"))" \
> +	    "False" \
> +	    "show initial value using Python, inferior 2"
> +    }
> +}
> +
> +proc test_copy_precise_memory_on_clone {precise_memory} {
> +    set value $precise_memory
> +    if {$precise_memory == "unspecified"} {
> +	set value off
> +    }
> +
> +    clean_restart
> +    gdb_test "show amdgpu precise-memory" "is off.*" \
> +	"show default amdgpu precise-memory"
> +    if {$precise_memory != "unspecified"} {
> +	gdb_test_no_output "set amdgpu precise-memory $value"
> +	gdb_test "show amdgpu precise-memory" "is $value.*" \
> +		 "show amdgpu precise-memory on original inferior"
> +    }
> +
> +    gdb_test "clone-inferior" "Added inferior 2.*"
> +    gdb_test "inferior 2"
> +    gdb_test "show amdgpu precise-memory" "is $value.*" \
> +	"show amdgpu precise-memory on cloned inferior"
> +}
> +
> +test_per_inferior
> +
> +foreach_with_prefix precise_memory { unspecified on off } {
> +    test_copy_precise_memory_on_clone $precise_memory
> +}
> diff --git a/gdb/testsuite/gdb.rocm/precise-memory-warning-sigsegv.cpp b/gdb/testsuite/gdb.rocm/precise-memory-warning-sigsegv.cpp
> new file mode 100644
> index 000000000000..58339e5391a6
> --- /dev/null
> +++ b/gdb/testsuite/gdb.rocm/precise-memory-warning-sigsegv.cpp
> @@ -0,0 +1,33 @@
> +/* Copyright 2021-2023 Free Software Foundation, Inc.
> +
> +   This file is part of GDB.
> +
> +   This program is free software; you can redistribute it and/or modify
> +   it under the terms of the GNU General Public License as published by
> +   the Free Software Foundation; either version 3 of the License, or
> +   (at your option) any later version.
> +
> +   This program is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +   GNU General Public License for more details.
> +
> +   You should have received a copy of the GNU General Public License
> +   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
> +
> +#include <hip/hip_runtime.h>
> +
> +__global__ void
> +kernel ()
> +{
> +  int *p = nullptr;
> +  *p = 1;
> +}
> +
> +int
> +main (int argc, char* argv[])
> +{
> +  hipLaunchKernelGGL (kernel, dim3 (1), dim3 (1), 0, 0);

I think the "modern" way to write this would be:

  kernel<<<1, 1>>> ();

This is mostly a remark, I don't mind using hipLaunchKernelGGL too much
either.

> +  hipDeviceSynchronize ();
> +  return 0;
> +}
> diff --git a/gdb/testsuite/gdb.rocm/precise-memory-warning-sigsegv.exp b/gdb/testsuite/gdb.rocm/precise-memory-warning-sigsegv.exp
> new file mode 100644
> index 000000000000..22e1f6eda254
> --- /dev/null
> +++ b/gdb/testsuite/gdb.rocm/precise-memory-warning-sigsegv.exp
> @@ -0,0 +1,49 @@
> +# Copyright 2021-2023 Free Software Foundation, Inc.
> +
> +# This file is part of GDB.
> +
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +
> +# Test that when "amdgpu precise-memory" is off, hitting a SIGSEGV shows a
> +# warning about the stop location maybe being inaccurate.
> +
> +load_lib rocm.exp
> +
> +require allow_hipcc_tests
> +
> +if { ![istarget "*-linux*"] } then {
> +    continue
> +}

Same remark here.

> +
> +standard_testfile .cpp
> +
> +if {[build_executable "failed to prepare" $testfile $srcfile {debug hip}]} {
> +    return
> +}
> +
> +proc do_test { } {
> +    clean_restart $::binfile
> +
> +    with_rocm_gpu_lock {
> +	if ![runto_main] {
> +	    return
> +	}
> +
> +	gdb_test_no_output "set amdgpu precise-memory off"
> +	gdb_test "continue" \
> +	    "SIGSEGV, Segmentation fault.*Warning: precise memory violation signal reporting is not enabled.*"
> +    }
> +}
> +
> +do_test
> diff --git a/gdb/testsuite/gdb.rocm/precise-memory.cpp b/gdb/testsuite/gdb.rocm/precise-memory.cpp
> new file mode 100644
> index 000000000000..6e0a4d9bc63b
> --- /dev/null
> +++ b/gdb/testsuite/gdb.rocm/precise-memory.cpp
> @@ -0,0 +1,32 @@
> +/* Copyright 2021-2023 Free Software Foundation, Inc.
> +
> +   This file is part of GDB.
> +
> +   This program is free software; you can redistribute it and/or modify
> +   it under the terms of the GNU General Public License as published by
> +   the Free Software Foundation; either version 3 of the License, or
> +   (at your option) any later version.
> +
> +   This program is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +   GNU General Public License for more details.
> +
> +   You should have received a copy of the GNU General Public License
> +   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
> +
> +#include <hip/hip_runtime.h>
> +
> +__global__ void
> +kernel ()
> +{
> +  __builtin_amdgcn_s_sleep (1);
> +}
> +
> +int
> +main (int argc, char* argv[])
> +{
> +  hipLaunchKernelGGL (kernel, dim3 (1), dim3 (1), 0, 0);

Same, maybe prefer the kernel<<<1, 1>>> notation.

> +  hipDeviceSynchronize ();
> +  return 0;
> +}
> diff --git a/gdb/testsuite/gdb.rocm/precise-memory.exp b/gdb/testsuite/gdb.rocm/precise-memory.exp
> new file mode 100644
> index 000000000000..bd2b12747c6f
> --- /dev/null
> +++ b/gdb/testsuite/gdb.rocm/precise-memory.exp
> @@ -0,0 +1,57 @@
> +# Copyright 2022-2023 Free Software Foundation, Inc.
> +
> +# This file is part of GDB.
> +
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +
> +# Test showing the "amdgpu precise-memory" setting.
> +
> +load_lib rocm.exp
> +
> +require allow_hipcc_tests
> +
> +standard_testfile .cpp
> +
> +if {[build_executable "failed to prepare" $testfile $srcfile {debug hip}]} {
> +    return
> +}
> +
> +proc do_test { } {
> +    clean_restart $::binfile
> +
> +    with_rocm_gpu_lock {
> +	if ![runto_main] {
> +	    return
> +	}
> +
> +	gdb_test "show amdgpu precise-memory" \
> +	    "AMDGPU precise memory access reporting is off \\(currently disabled\\)." \
> +	    "show precise-memory setting in CLI before"
> +
> +	if {[hip_device_supports_precise_memory]} {
> +	    gdb_test_no_output "set amdgpu precise-memory on"
> +	    set cli_effective_value "enabled"
> +	} else {
> +	    gdb_test "set amdgpu precise-memory on" \
> +		"warning: AMDGPU precise memory access reporting could not be enabled."
> +	    set cli_effective_value "disabled"
> +	}
> +
> +	gdb_test "show amdgpu precise-memory" \
> +	    "AMDGPU precise memory access reporting is on \\(currently ${cli_effective_value}\\)." \
> +	    "show precise-memory setting in CLI after"
> +    }
> +}
> +
> +do_test
> diff --git a/gdb/testsuite/lib/rocm.exp b/gdb/testsuite/lib/rocm.exp
> index 98a3b308228d..22b294a5efae 100644
> --- a/gdb/testsuite/lib/rocm.exp
> +++ b/gdb/testsuite/lib/rocm.exp
> @@ -99,6 +99,56 @@ gdb_caching_proc allow_hipcc_tests {} {
>      return 1
>  }
>  
> +# ROCM_PATH is used by hipcc as well.
> +if {[info exists env(ROCM_PATH)]} {
> +    set rocm_path $env(ROCM_PATH)
> +} else {
> +    set rocm_path "/opt/rocm"
> +}
> +
> +# Get the gpu target to be passed to e.g., -mcpu=.
> +#
> +# If HCC_AMDGPU_TARGET is set in the environment, use it.  Otherwise,
> +# try reading it from the system using the rocm_agent_enumerator
> +# utility.
> +
> +proc hcc_amdgpu_target {} {

There is a hcc_amdgpu_targets proc which enumerates the architecture of
each agent present on the system.  This is a fairly recent addition, it
might have been introduced after you prepared this series.

> +    if {![info exists ::gdb_hip_gpu]} {
> +	# Look for HCC_AMDGPU_TARGET (same env var hipcc uses).  If
> +	# that fails, try using rocm_agent_enumerator (again, same as
> +	# hipcc does).
> +	if {[info exists env(HCC_AMDGPU_TARGET)]} {
> +	    set targets = $env(HCC_AMDGPU_TARGET);
> +	} else {
> +	    set result \
> +		[remote_exec host \
> +		     "${::rocm_path}/bin/rocm_agent_enumerator -t GPU"]
> +	    if {[lindex $result 0] != 0} {
> +		error "rocm_agent_enumerator failed"
> +	    }
> +	    set targets [lindex $result 1]
> +	}
> +
> +	set ::gdb_hip_gpu ""
> +	foreach val $targets {
> +	    # Ignore the 'gfx000' target reported by
> +	    # rocm_agent_enumerator.
> +	    if {$val != "gfx000"} {
> +		set ::gdb_hip_gpu $val
> +		break
> +	    }
> +	}
> +
> +	if {$::gdb_hip_gpu == ""} {
> +	    error "No valid AMD GPU target specified or found.\
> +		   Please specify a valid target using the\
> +		   HCC_AMDGPU_TARGET environment variable."
> +	}
> +    }
> +
> +    return $::gdb_hip_gpu
> +}
> +
>  # The lock file used to ensure that only one GDB has access to the GPU
>  # at a time.
>  set gpu_lock_filename $objdir/gpu-parallel.lock
> @@ -186,3 +236,12 @@ proc hip_devices_support_debug_multi_process {} {
>      }
>      return 1
>  }
> +
> +# Return true if the device supports precise memory.

Using hcc_amdgpu_targets, you could have a function which checks that
all agents in the system support precise memory, not just the first one
detected.  This will reflect how `set amdgpu precise-memory` works.

> +
> +proc hip_device_supports_precise_memory {} {
> +    set target [hcc_amdgpu_target]
> +    set unsupported_targets \
> +	{gfx900 gfx906 gfx908 gfx1010 gfx1011 gfx1012 gfx1030 gfx1031 gfx1032}
> +    return [expr [lsearch -exact $unsupported_targets $target] == -1]
> +}
> -- 
> 2.42.0
>
  

>>>>> "Simon" == Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:

Simon> It can be set before starting the inferior, in which case GDB will
Simon> attempt to apply what the user wants when attaching amd-dbgapi.  If the
Simon> user has requested to enable precise memory, but it can't be enabled
Simon> (not all hardware supports it), GDB prints a warning.

I was curious if this setting is preserved by fork or exec and so ought
to be copied when those events occur.

Tom
  

>> @@ -1326,6 +1338,36 @@ amd_dbgapi_target::stopped_by_hw_breakpoint ()
>>    return false;
>>  }
>>  
>> +/* Set the process's memory access reporting precision.
>> +
>> +   The precision can be ::AMD_DBGAPI_MEMORY_PRECISION_PRECISE (waves wait for
>> +   memory instructions to complete before executing further instructions), or
>> +   ::AMD_DBGAPI_MEMORY_PRECISION_NONE (memory instructions execute normally).
>> +
>> +   Returns true if the precision is supported by the architecture of all agents
>> +   in the process, or false if at least one agent does not support the
>> +   requested precision.
>> +
>> +   An error is thrown if setting the precision results in a status other than
>> +   ::AMD_DBGAPI_STATUS_SUCCESS or ::AMD_DBGAPI_STATUS_ERROR_NOT_SUPPORTED.  */
>> +
> 
> Would it be simpler if this helper function received a bool parameter
> instead of the amd_dbgapi_memory_precision_t one?  This could avoid
> repeating this
> 
>      amd_dbgapi_memory_precision_t memory_precision
>        = (info->precise_memory.requested
>           ? AMD_DBGAPI_MEMORY_PRECISION_PRECISE
>           : AMD_DBGAPI_MEMORY_PRECISION_NONE);
> 
> before calling it.
Indeed.  In fact, we can factor out more... I came up with:

    static void
    try_set_process_memory_precision (amd_dbgapi_inferior_info &info)
    {
      auto mode = (info.precise_memory.requested
      	       ? AMD_DBGAPI_MEMORY_PRECISION_PRECISE
    	       : AMD_DBGAPI_MEMORY_PRECISION_NONE);
      amd_dbgapi_status_t status
        = amd_dbgapi_set_memory_precision (info.process_id, mode);

      if (status == AMD_DBGAPI_STATUS_ERROR_NOT_SUPPORTED)
        warning (_("AMDGPU precise memory access reporting could not be enabled."));
      else if (status != AMD_DBGAPI_STATUS_SUCCESS)
        error (_("amd_dbgapi_set_memory_precision failed (%s)"),
    	   get_status_string (status));
    }

... such that callers just need to do:

    try_set_process_memory_precision (*info);

I'll put that in v2, unless you think it's a bad idea.

>> @@ -1785,6 +1873,29 @@ amd_dbgapi_remove_breakpoint_callback
>>    return AMD_DBGAPI_STATUS_SUCCESS;
>>  }
>>  
>> +/* signal_received observer.  */
>> +
>> +static void
>> +amd_dbgapi_target_signal_received (gdb_signal sig)
>> +{
>> +  amd_dbgapi_inferior_info *info
>> +    = get_amd_dbgapi_inferior_info (current_inferior ());
>> +
>> +  if (info->process_id == AMD_DBGAPI_PROCESS_NONE)
>> +    return;
>> +
>> +  if (!ptid_is_gpu (inferior_thread ()->ptid))
>> +    return;
>> +
>> +  if (sig != GDB_SIGNAL_SEGV && sig != GDB_SIGNAL_BUS)
>> +    return;
>> +
>> +  if (!info->precise_memory.enabled)
>> +    gdb_printf ("\
> 
> I think there should be a _() surrounding the string.

Done.

>> +The @code{set amdgpu precise-memory} parameter is per-inferior.  When an
>              ^
> Isn't the parameter name just "amdgpu precise-memory"?

Yes, done.

>> diff --git a/gdb/testsuite/gdb.rocm/precise-memory-exec.c b/gdb/testsuite/gdb.rocm/precise-memory-exec.c
>> new file mode 100644
>> index 000000000000..f0659a63fc5a
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.rocm/precise-memory-exec.c
>> @@ -0,0 +1,44 @@
>> +/* Copyright 2021-2023 Free Software Foundation, Inc.
>> +
>> +   This file is part of GDB.
>> +
>> +   This program is free software; you can redistribute it and/or modify
>> +   it under the terms of the GNU General Public License as published by
>> +   the Free Software Foundation; either version 3 of the License, or
>> +   (at your option) any later version.
>> +
>> +   This program is distributed in the hope that it will be useful,
>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> +   GNU General Public License for more details.
>> +
>> +   You should have received a copy of the GNU General Public License
>> +   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
>> +
>> +#include <unistd.h>
>> +#include <stdlib.h>
>> +#include <stdio.h>
>> +
>> +static void
>> +second (void)
>> +{
>> +}
>> +
>> +int
>> +main (int argc, char **argv)
>> +{
>> +  if (argc == 1)
>> +    {
>> +      /* First invocation */
> 
> Should the comment end with ".  "?

Done.

> 
>> +      int ret = execl (argv[0], argv[0], "Hello", NULL);
>> +      perror ("exec");
>> +      abort ();
>> +    }
>> +  else
>> +    {
>> +      /* Second invocation */
> 
> Here also.

Done.

> 
>> +      second ();
>> +    }
>> +
>> +  return 0;
>> +}
>> diff --git a/gdb/testsuite/gdb.rocm/precise-memory-exec.exp b/gdb/testsuite/gdb.rocm/precise-memory-exec.exp
>> new file mode 100644
>> index 000000000000..26be6cf72146
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.rocm/precise-memory-exec.exp
>> @@ -0,0 +1,62 @@
>> +# Copyright 2021-2023 Free Software Foundation, Inc.
>> +
>> +# This file is part of GDB.
>> +
>> +# This program is free software; you can redistribute it and/or modify
>> +# it under the terms of the GNU General Public License as published by
>> +# the Free Software Foundation; either version 3 of the License, or
>> +# (at your option) any later version.
>> +
>> +# This program is distributed in the hope that it will be useful,
>> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> +# GNU General Public License for more details.
>> +
>> +# You should have received a copy of the GNU General Public License
>> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
>> +
>> +# Test that the "set amdgpu precise-memory" setting is inherited by an inferior
>> +# created following an exec.
>> +
>> +load_lib rocm.exp
>> +
>> +require allow_hipcc_tests
>> +
>> +if { ![istarget "*-linux*"] } then {
>> +    continue
>> +}
> 
> Should this test be integrated in allow_hipcc_test?  This would avoid
> having to repeat it in multiple testcases (and all testcases do not have
> such guard).
> 
> Also, I'm not sure if there is any non-linux configuration which can
> satisfy allow_hipcc_tests, which would make this test redundant.

Yeah I think we can put it in allow_hipcc_tests.  If/when we want to run
this test on, let's say, Windows, we will be able to change the check in
allow_hipcc_tests.

The existing tests in the upstream repo don't have the linux check, I
guess there should have been some checks.  I'll add a new preparatory
patch in v2.

>> diff --git a/gdb/testsuite/gdb.rocm/precise-memory-warning-sigsegv.cpp b/gdb/testsuite/gdb.rocm/precise-memory-warning-sigsegv.cpp
>> new file mode 100644
>> index 000000000000..58339e5391a6
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.rocm/precise-memory-warning-sigsegv.cpp
>> @@ -0,0 +1,33 @@
>> +/* Copyright 2021-2023 Free Software Foundation, Inc.
>> +
>> +   This file is part of GDB.
>> +
>> +   This program is free software; you can redistribute it and/or modify
>> +   it under the terms of the GNU General Public License as published by
>> +   the Free Software Foundation; either version 3 of the License, or
>> +   (at your option) any later version.
>> +
>> +   This program is distributed in the hope that it will be useful,
>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> +   GNU General Public License for more details.
>> +
>> +   You should have received a copy of the GNU General Public License
>> +   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
>> +
>> +#include <hip/hip_runtime.h>
>> +
>> +__global__ void
>> +kernel ()
>> +{
>> +  int *p = nullptr;
>> +  *p = 1;
>> +}
>> +
>> +int
>> +main (int argc, char* argv[])
>> +{
>> +  hipLaunchKernelGGL (kernel, dim3 (1), dim3 (1), 0, 0);
> 
> I think the "modern" way to write this would be:
> 
>   kernel<<<1, 1>>> ();
> 
> This is mostly a remark, I don't mind using hipLaunchKernelGGL too much
> either.

I think we wanted to migrate all to the new form, let's go with the new
form.

>> diff --git a/gdb/testsuite/lib/rocm.exp b/gdb/testsuite/lib/rocm.exp
>> index 98a3b308228d..22b294a5efae 100644
>> --- a/gdb/testsuite/lib/rocm.exp
>> +++ b/gdb/testsuite/lib/rocm.exp
>> @@ -99,6 +99,56 @@ gdb_caching_proc allow_hipcc_tests {} {
>>      return 1
>>  }
>>  
>> +# ROCM_PATH is used by hipcc as well.
>> +if {[info exists env(ROCM_PATH)]} {
>> +    set rocm_path $env(ROCM_PATH)
>> +} else {
>> +    set rocm_path "/opt/rocm"
>> +}
>> +
>> +# Get the gpu target to be passed to e.g., -mcpu=.
>> +#
>> +# If HCC_AMDGPU_TARGET is set in the environment, use it.  Otherwise,
>> +# try reading it from the system using the rocm_agent_enumerator
>> +# utility.
>> +
>> +proc hcc_amdgpu_target {} {
> 
> There is a hcc_amdgpu_targets proc which enumerates the architecture of
> each agent present on the system.  This is a fairly recent addition, it
> might have been introduced after you prepared this series.

Oh, that's true, no need to introduce hcc_amdgpu_target.

>> @@ -186,3 +236,12 @@ proc hip_devices_support_debug_multi_process {} {
>>      }
>>      return 1
>>  }
>> +
>> +# Return true if the device supports precise memory.
> 
> Using hcc_amdgpu_targets, you could have a function which checks that
> all agents in the system support precise memory, not just the first one
> detected.  This will reflect how `set amdgpu precise-memory` works.

Oh, right, we have this downstream.  I sync'ed the patch with the
downstream code.

Thanks, will send a v2.

Simon
  

On 9/14/23 10:10, Tom Tromey wrote:
>>>>>> "Simon" == Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:
> 
> Simon> It can be set before starting the inferior, in which case GDB will
> Simon> attempt to apply what the user wants when attaching amd-dbgapi.  If the
> Simon> user has requested to enable precise memory, but it can't be enabled
> Simon> (not all hardware supports it), GDB prints a warning.
> 
> I was curious if this setting is preserved by fork or exec and so ought
> to be copied when those events occur.

Yes, it is mentioned in the commit message, and there are tests for it
in this patch.  Or maybe I don't understand what you mean.

Simon
  

>>>>> "Simon" == Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:

>> I was curious if this setting is preserved by fork or exec and so ought
>> to be copied when those events occur.

Simon> Yes, it is mentioned in the commit message, and there are tests for it
Simon> in this patch.  Or maybe I don't understand what you mean.

I just totally missed it...?!  Sorry about that.

Tom
  

On 9/14/23 12:18, Tom Tromey wrote:
>>>>>> "Simon" == Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:
> 
>>> I was curious if this setting is preserved by fork or exec and so ought
>>> to be copied when those events occur.
> 
> Simon> Yes, it is mentioned in the commit message, and there are tests for it
> Simon> in this patch.  Or maybe I don't understand what you mean.
> 
> I just totally missed it...?!  Sorry about that.
> 
> Tom

No problem, better be safe than sorry.

Simon