[PATCH v2 07/47] gdb, gdbserver, gdbsupport: add 'device' tag to XML target description

[Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>]

From: Nils-Christian Kempke <nils-christian.kempke@intel.com>

Add <device> tag to the XML target description.  The tag is a list of
device attributes.  The extension enables passing device information
within the target description XML sent from gdbserver to gdb.

Co-authored-by: Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
---
 gdb/NEWS                    |  8 ++++
 gdb/doc/gdb.texinfo         | 25 +++++++++++++
 gdb/features/gdb-target.dtd | 19 +++++++++-
 gdb/target-descriptions.c   | 19 ++++++++++
 gdb/xml-tdesc.c             | 76 ++++++++++++++++++++++++++++++++++++++
 gdbserver/tdesc.cc          | 16 ++++++++
 gdbserver/tdesc.h           |  3 ++
 gdbsupport/tdesc.cc         | 40 ++++++++++++++++++++
 gdbsupport/tdesc.h          | 90 +++++++++++++++++++++++++++++++++++++++++++++
 9 files changed, 295 insertions(+), 1 deletion(-)

diff --git a/gdb/NEWS b/gdb/NEWS
index 361d7726ba0f7065b1ad78c34aa0decb860f4e9c..8f8aa1462f5f757bda3d25ca60e2eba80660bcb6 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -174,6 +174,14 @@ vFile:stat
   vFile:fstat but takes a filename rather than an open file
   descriptor.
 
+* Changed remote packets
+
+qXfer:features:read:target.xml
+
+  The XML that is sent as a response can now include a "device" element
+  that can be used for passing information when the remote inferior
+  represents a device, e.g.  a GPU.
+
 *** Changes in GDB 15
 
 * The MPX commands "show/set mpx bound" have been deprecated, as Intel
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 85ac3d9aab63d790b66aae8bfe38156b44f4e8fc..ddd414659fcc554813fc2a12a79e581ad7a188b9 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -48552,6 +48552,7 @@ are explained further below.
   @r{[}@var{architecture}@r{]}
   @r{[}@var{osabi}@r{]}
   @r{[}@var{compatible}@r{]}
+  @r{[}@var{device}@r{]}
   @r{[}@var{feature}@dots{}@r{]}
 </target>
 @end smallexample
@@ -48649,6 +48650,30 @@ capability with @samp{<compatible>} is as follows:
   <compatible>spu</compatible>
 @end smallexample
 
+@subsection Device Information
+@cindex <device>
+
+A @samp{<device>} element can be used for passing device information
+for when, e.g.@: the remote target represents a device, such as a GPU.
+@value{GDBN} can then use this information to display it to the user
+for informative purposes or to execute device-specific functions
+appropriately.  The element contains a number of attributes, best
+shown with the example below.  All attributes are optional.
+
+@smallexample
+  <device vendor-id="0x8086"
+          target-id="0x56a1"
+          family="abc"
+          model="xyz"
+          stepping="3"
+          name="Intel(R) Arc(TM) A750 Graphics"
+          pci-slot="03:00.0"
+          uuid="0003000856a18086"
+          total-cores="448"
+          total-threads="3584"
+          subdevice-id="1"/>
+@end smallexample
+
 @subsection Features
 @cindex <feature>
 
diff --git a/gdb/features/gdb-target.dtd b/gdb/features/gdb-target.dtd
index d07703fca8b6b22bffb8acea99b40ce7f7a590c8..4afaffc6d0c228ee14f2e46492b152245dea3990 100644
--- a/gdb/features/gdb-target.dtd
+++ b/gdb/features/gdb-target.dtd
@@ -9,7 +9,9 @@
 <!-- The osabi and compatible elements were added post GDB 6.8.  The version
      wasn't bumped, since older GDBs silently ignore unknown elements.  -->
 
-<!ELEMENT target	(architecture?, osabi?, compatible*, feature*)>
+<!ELEMENT target
+	(architecture?, osabi?, compatible*, device?, feature*)>
+
 <!ATTLIST target
 	version		CDATA	#FIXED "1.0">
 
@@ -19,6 +21,21 @@
 
 <!ELEMENT compatible	(#PCDATA)>
 
+<!ELEMENT device	EMPTY>
+<!ATTLIST device
+	vendor-id	CDATA	#IMPLIED
+	target-id	CDATA	#IMPLIED
+	family		CDATA	#IMPLIED
+	model		CDATA	#IMPLIED
+	stepping	CDATA	#IMPLIED
+	name		CDATA	#IMPLIED
+	pci-slot	CDATA	#IMPLIED
+	uuid		CDATA	#IMPLIED
+	total-cores	CDATA	#IMPLIED
+	total-threads	CDATA	#IMPLIED
+	subdevice-id	CDATA	#IMPLIED
+	>
+
 <!ELEMENT feature
 	((vector | flags | struct | union )*, reg*)>
 <!ATTLIST feature
diff --git a/gdb/target-descriptions.c b/gdb/target-descriptions.c
index 3ee8a751f3b303b7d02df40b3b3836c8a8c83066..34a00265b4bb601995baffcd0d99ce26af4264cc 100644
--- a/gdb/target-descriptions.c
+++ b/gdb/target-descriptions.c
@@ -358,6 +358,9 @@ struct target_desc : tdesc_element
   /* The list of compatible architectures reported by the target.  */
   std::vector<tdesc_compatible_info_up> compatible;
 
+  /* The device reported by the target, if any.  */
+  tdesc_device_up device;
+
   /* Any architecture-specific properties specified by the target.  */
   std::vector<property> properties;
 
@@ -643,6 +646,22 @@ tdesc_osabi_name (const struct target_desc *target_desc)
   return nullptr;
 }
 
+/* See gdbsupport/tdesc.h.  */
+
+void
+set_tdesc_device_info (target_desc *target_desc, tdesc_device *device)
+{
+  target_desc->device.reset (device);
+}
+
+/* See gdbsupport/tdesc.h.  */
+
+const tdesc_device *
+tdesc_device_info (const target_desc *target_desc)
+{
+  return target_desc->device.get ();
+}
+
 /* Return 1 if this target description includes any registers.  */
 
 int
diff --git a/gdb/xml-tdesc.c b/gdb/xml-tdesc.c
index 436c493d4f914eb71a80bcbc08dc2ddd38c72027..61cba42e9eee2ec4cc66e14a120c5bef909e48b0 100644
--- a/gdb/xml-tdesc.c
+++ b/gdb/xml-tdesc.c
@@ -137,6 +137,65 @@ tdesc_end_compatible (struct gdb_xml_parser *parser,
   tdesc_add_compatible (data->tdesc, arch);
 }
 
+/* Handle the end of a <device> element and its value.  */
+
+static void
+tdesc_start_device (struct gdb_xml_parser *parser,
+		    const gdb_xml_element *element,
+		    void *user_data, std::vector<gdb_xml_value> &attributes)
+{
+  tdesc_parsing_data *data = (struct tdesc_parsing_data *) user_data;
+  tdesc_device *device = new tdesc_device ();
+
+  gdb_xml_value *attr;
+
+  attr = xml_find_attribute (attributes, "vendor-id");
+  if (attr != nullptr)
+    device->vendor_id = * (ULONGEST *) attr->value.get ();
+
+  attr = xml_find_attribute (attributes, "target-id");
+  if (attr != nullptr)
+    device->target_id = * (ULONGEST *) attr->value.get ();
+
+  attr = xml_find_attribute (attributes, "family");
+  if (attr != nullptr)
+    device->family = (char *) attr->value.get ();
+
+  attr = xml_find_attribute (attributes, "model");
+  if (attr != nullptr)
+    device->model = (char *) attr->value.get ();
+
+  attr = xml_find_attribute (attributes, "stepping");
+  if (attr != nullptr)
+    device->stepping = * (ULONGEST *) attr->value.get ();
+
+  attr = xml_find_attribute (attributes, "name");
+  if (attr != nullptr)
+    device->name = (char *) attr->value.get ();
+
+  attr = xml_find_attribute (attributes, "pci-slot");
+  if (attr != nullptr)
+    device->pci_slot = (char *) attr->value.get ();
+
+  attr = xml_find_attribute (attributes, "uuid");
+  if (attr != nullptr)
+    device->uuid = (char *) attr->value.get ();
+
+  attr = xml_find_attribute (attributes, "total-cores");
+  if (attr != nullptr)
+    device->total_cores = * (ULONGEST *) attr->value.get ();
+
+  attr = xml_find_attribute (attributes, "total-threads");
+  if (attr != nullptr)
+    device->total_threads = * (ULONGEST *) attr->value.get ();
+
+  attr = xml_find_attribute (attributes, "subdevice-id");
+  if (attr != nullptr)
+    device->subdevice_id = * (ULONGEST *) attr->value.get ();
+
+  set_tdesc_device_info (data->tdesc, device);
+}
+
 /* Handle the start of a <target> element.  */
 
 static void
@@ -588,6 +647,21 @@ static const struct gdb_xml_element feature_children[] = {
   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 };
 
+static const struct gdb_xml_attribute device_attributes[] = {
+  { "vendor-id", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
+  { "target-id", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
+  { "family", GDB_XML_AF_OPTIONAL, NULL, NULL },
+  { "model", GDB_XML_AF_OPTIONAL, NULL, NULL },
+  { "stepping", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
+  { "name", GDB_XML_AF_OPTIONAL, NULL, NULL },
+  { "pci-slot", GDB_XML_AF_OPTIONAL, NULL, NULL },
+  { "uuid", GDB_XML_AF_OPTIONAL, NULL, NULL },
+  { "total-cores", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
+  { "total-threads", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
+  { "subdevice-id", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL},
+  { NULL, GDB_XML_EF_NONE, NULL, NULL }
+};
+
 static const struct gdb_xml_attribute target_attributes[] = {
   { "version", GDB_XML_AF_NONE, NULL, NULL },
   { NULL, GDB_XML_AF_NONE, NULL, NULL }
@@ -600,6 +674,8 @@ static const struct gdb_xml_element target_children[] = {
     NULL, tdesc_end_osabi },
   { "compatible", NULL, NULL, GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
     NULL, tdesc_end_compatible },
+  { "device", device_attributes, NULL, GDB_XML_EF_OPTIONAL,
+    tdesc_start_device, NULL },
   { "feature", feature_attributes, feature_children,
     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
     tdesc_start_feature, NULL },
diff --git a/gdbserver/tdesc.cc b/gdbserver/tdesc.cc
index da1287abbbed5933bf8ceddd4aa5d7a70ad4d473..dc89ac1cd4f3a189b2e3ba30998119e8e4df4531 100644
--- a/gdbserver/tdesc.cc
+++ b/gdbserver/tdesc.cc
@@ -190,6 +190,22 @@ set_tdesc_osabi (struct target_desc *target_desc, enum gdb_osabi osabi)
 
 /* See gdbsupport/tdesc.h.  */
 
+void
+set_tdesc_device_info (target_desc *target_desc, tdesc_device *device)
+{
+  target_desc->device.reset (device);
+}
+
+/* See gdbsupport/tdesc.h.  */
+
+const tdesc_device *
+tdesc_device_info (const target_desc *target_desc)
+{
+  return target_desc->device.get ();
+}
+
+/* See gdbsupport/tdesc.h.  */
+
 const char *
 tdesc_get_features_xml (const target_desc *tdesc)
 {
diff --git a/gdbserver/tdesc.h b/gdbserver/tdesc.h
index 9264786de51173c262aadcaa31d205f0b274b7c4..3eb6d67db02f7f36b197d499f456d9cabeffa833 100644
--- a/gdbserver/tdesc.h
+++ b/gdbserver/tdesc.h
@@ -60,6 +60,9 @@ struct target_desc final : tdesc_element
   /* The value of <osabi> element in the XML, replying GDB.  */
   gdb::unique_xmalloc_ptr<char> osabi;
 
+  /* The value of the <device> element in the XML, replying GDB.  */
+  tdesc_device_up device;
+
 public:
   target_desc ()
     : registers_size (0)
diff --git a/gdbsupport/tdesc.cc b/gdbsupport/tdesc.cc
index 080d39c485dc5d9d7ced21e067bec5391b132c94..ae7a7b36c7ca2d265c5707437239801599e7fb62 100644
--- a/gdbsupport/tdesc.cc
+++ b/gdbsupport/tdesc.cc
@@ -417,6 +417,8 @@ void print_xml_feature::visit_pre (const target_desc *e)
   for (const auto &c : compatible_list)
     add_line ("<compatible>%s</compatible>",
 	      tdesc_compatible_info_arch_name (c));
+
+  this->visit (tdesc_device_info (e));
 #endif
 }
 
@@ -426,6 +428,44 @@ void print_xml_feature::visit_post (const target_desc *e)
   add_line ("</target>");
 }
 
+void
+print_xml_feature::visit (const tdesc_device *device)
+{
+  if (device == nullptr)
+    return;
+
+  std::string tmp = "<device";
+  if (device->vendor_id.has_value ())
+    string_appendf (tmp, " vendor-id=\"0x%04" PRIx32 "\"",
+		    *device->vendor_id);
+
+  if (device->target_id.has_value ())
+    string_appendf (tmp, " target-id=\"0x%04" PRIx32 "\"",
+		    *device->target_id);
+
+  string_appendf (tmp, " family=\"%s\"", device->family.c_str ());
+  string_appendf (tmp, " model=\"%s\"", device->model.c_str ());
+
+  if (device->stepping.has_value ())
+    string_appendf (tmp, " stepping=\"%d\"", *device->stepping);
+
+  string_appendf (tmp, " name=\"%s\"", device->name.c_str ());
+  string_appendf (tmp, " pci-slot=\"%s\"", device->pci_slot.c_str ());
+  string_appendf (tmp, " uuid=\"%s\"", device->uuid.c_str ());
+
+  if (device->total_cores.has_value ())
+    string_appendf (tmp, " total-cores=\"%ld\"", *device->total_cores);
+
+  if (device->total_threads.has_value ())
+    string_appendf (tmp, " total-threads=\"%ld\"", *device->total_threads);
+
+  if (device->subdevice_id.has_value ())
+    string_appendf (tmp, " subdevice-id=\"%d\"", *device->subdevice_id);
+
+  string_appendf (tmp, "/>");
+  add_line (tmp);
+}
+
 /* See gdbsupport/tdesc.h.  */
 
 void
diff --git a/gdbsupport/tdesc.h b/gdbsupport/tdesc.h
index c9e7603369cbf986187908c2d1f8fbe35a0dc02d..29de4d231f16667c8297bcbe403f683c30a28762 100644
--- a/gdbsupport/tdesc.h
+++ b/gdbsupport/tdesc.h
@@ -26,6 +26,7 @@ struct tdesc_type_builtin;
 struct tdesc_type_vector;
 struct tdesc_type_with_fields;
 struct tdesc_reg;
+struct tdesc_device;
 struct target_desc;
 
 /* The interface to visit different elements of target description.  */
@@ -56,6 +57,9 @@ class tdesc_element_visitor
 
   virtual void visit (const tdesc_reg *e)
   {}
+
+  virtual void visit (const tdesc_device *e)
+  {}
 };
 
 class tdesc_element
@@ -315,6 +319,84 @@ struct tdesc_feature : tdesc_element
 
 typedef std::unique_ptr<tdesc_feature> tdesc_feature_up;
 
+/* The device information in a target description.  */
+
+struct tdesc_device : tdesc_element
+{
+  tdesc_device ()
+  {
+    family = "-";
+    model = "-";
+    name = "-";
+    pci_slot = "-";
+    uuid = "-";
+  }
+
+  virtual ~tdesc_device () = default;
+
+  DISABLE_COPY_AND_ASSIGN (tdesc_device);
+
+  /* The id of the device vendor.  */
+  std::optional<uint32_t> vendor_id;
+
+  /* The id of the device, given by its vendor.  */
+  std::optional<uint32_t> target_id;
+
+  /* The family of the device.  */
+  std::string family;
+
+  /* The model of the device.  */
+  std::string model;
+
+  /* The stepping of the device.  */
+  std::optional<uint32_t> stepping;
+
+  /* The name of the device.  */
+  std::string name;
+
+  /* The location where the device is positioned.  */
+  std::string pci_slot;
+
+  /* The UUID of the device.  */
+  std::string uuid;
+
+  /* The number of cores available in the device.  */
+  std::optional<size_t> total_cores;
+
+  /* The number of threads available in the device.  */
+  std::optional<size_t> total_threads;
+
+  /* The subdevice id, if this device is a subdevice.  */
+  std::optional<uint32_t> subdevice_id;
+
+  void accept (tdesc_element_visitor &v) const override
+  {
+    v.visit (this);
+  }
+
+  bool operator== (const tdesc_device &other) const
+  {
+    return (vendor_id == other.vendor_id
+	    && target_id == other.target_id
+	    && family == other.family
+	    && model == other.model
+	    && stepping == other.stepping
+	    && name == other.name
+	    && pci_slot == other.pci_slot
+	    && uuid == other.uuid
+	    && total_cores == other.total_cores
+	    && total_threads == other.total_threads
+	    && subdevice_id == other.subdevice_id);
+  }
+
+  bool operator!= (const tdesc_device &other) const
+  {
+    return !(*this == other);
+  }
+};
+
+typedef std::unique_ptr<tdesc_device> tdesc_device_up;
+
 /* A deleter adapter for a target_desc.  There are different
    implementations of this deleter class in gdb and gdbserver because even
    though the target_desc name is shared between the two projects, the
@@ -347,6 +429,13 @@ void set_tdesc_osabi (target_desc *target_desc, enum gdb_osabi osabi);
    or NULL if no osabi was specified.  */
 const char *tdesc_osabi_name (const struct target_desc *target_desc);
 
+/* Set TARGET_DESC's device information.  */
+void set_tdesc_device_info (target_desc *target_desc, tdesc_device *device);
+
+/* Return the device information associated with this target
+   description or NULL if device info does not exist.  */
+const tdesc_device *tdesc_device_info (const target_desc *target_desc);
+
 /* Return the type associated with ID in the context of FEATURE, or
    NULL if none.  */
 struct tdesc_type *tdesc_named_type (const struct tdesc_feature *feature,
@@ -439,6 +528,7 @@ class print_xml_feature : public tdesc_element_visitor
   void visit (const tdesc_type_vector *type) override;
   void visit (const tdesc_type_with_fields *type) override;
   void visit (const tdesc_reg *reg) override;
+  void visit (const tdesc_device *device) override;
 
 private:
 

-- 
2.34.1

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