Dynamically composite xml in reply to GDB

GDBserver still uses pre-generated target descriptions in order to
reply to GDB's query on target description (see xml-builtin-generated.c
in GDBserver build directory).  This patch teaches GDBserver to
create XML contents according to the target descriptions rather than
using pre-generated ones.

First, change target feature c files to pass the feature xml file
name to tdesc_create_feature, so that target description in GDBserver
can record them, and create XML contents from these features in
buffer, like

  ...
  <xi:include href="$FEATURE1_XML_NAME"/>
  <xi:include href="$FEATURE2_XML_NAME"/>
  ...

and send this buffer back to GDB.

Note that this patch reuses target_desc.xmltarget a little bit, which is
to hold the XML contents dynamically generated in tdesc_get_features_xml.
However, it is not xfree'ed in ~target_desc, because we can't tell it is
from xstrdup or a literal string.  Since we don't delete target_desc,
there is no memory leak yet.  After we change all target descriptions to
the new style, target_desc.xmltarget is from xstrdup, then, we can safely
xfree it in ~target_desc.

gdb:

2017-09-05  Yao Qi  <yao.qi@linaro.org>

	* arch/tdesc.h (tdesc_create_feature): Add an argument xml.
	* target-descriptions.c (tdesc_create_feature): Likewise, and
	adjust code.
	* features/i386/32bit-avx.c: Re-generated.
	* features/i386/32bit-avx512.c: Re-generated.
	* features/i386/32bit-core.c: Re-generated.
	* features/i386/32bit-linux.c: Re-generated.
	* features/i386/32bit-mpx.c: Re-generated.
	* features/i386/32bit-pkeys.c: Re-generated.
	* features/i386/32bit-sse.c: Re-generated.

gdb/gdbserver:

2017-09-05  Yao Qi  <yao.qi@linaro.org>

	* linux-x86-tdesc.c: Don't include <inttypes.h>.
	(i386_linux_read_description) [!IN_PROCESS_AGENT]: Call
	set_tdesc_architecture and set_tdesc_osabi.  Remove code setting
	.xmltarget.
	* server.c (get_features_xml): Call tdesc_get_features_xml.
	* tdesc.c (set_tdesc_architecture): New function.
	(set_tdesc_osabi): New function.
	(tdesc_get_features_xml): New function.
	(tdesc_create_feature): Add an argument.
	* tdesc.h (struct target_desc) <features>: New field.
	<arch, osabi>: New field.
	(~target_desc): xfree features, arch, and osabi.
	(target_desc::oerator==): Don't compare .xmltarget.
	[!IN_PROCESS_AGENT] (set_tdesc_architecture): Declare.
	(set_tdesc_osabi): Likewise.
	(tdesc_get_features_xml): Likewise.

1 files changed, 61 insertions, 1 deletions

diff --git a/gdb/gdbserver/tdesc.c b/gdb/gdbserver/tdesc.c
index 4504c9b..0b5096b 100644
--- a/gdb/gdbserver/tdesc.c
+++ b/gdb/gdbserver/tdesc.c
@@ -61,6 +61,62 @@ current_target_desc (void)
 
   return current_process ()->tdesc;
 }
+
+void
+set_tdesc_architecture (struct target_desc *target_desc,
+			const char *name)
+{
+  target_desc->arch = xstrdup (name);
+}
+
+void
+set_tdesc_osabi (struct target_desc *target_desc, const char *name)
+{
+  target_desc->osabi = xstrdup (name);
+}
+
+/* Return a string which is of XML format, including XML target
+   description to be sent to GDB.  */
+
+const char *
+tdesc_get_features_xml (target_desc *tdesc)
+{
+  /* Either .xmltarget or .features is not NULL.  */
+  gdb_assert (tdesc->xmltarget != NULL
+	      || (tdesc->features != NULL
+		  && tdesc->arch != NULL
+		  && tdesc->osabi != NULL));
+
+  if (tdesc->xmltarget == NULL)
+    {
+      std::string buffer ("@<?xml version=\"1.0\"?>");
+
+      buffer += "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">";
+      buffer += "<target>";
+      buffer += "<architecture>";
+      buffer += tdesc->arch;
+      buffer += "</architecture>";
+
+      buffer += "<osabi>";
+      buffer += tdesc->osabi;
+      buffer += "</osabi>";
+
+      char *xml;
+
+      for (int i = 0; VEC_iterate (char_ptr, tdesc->features, i, xml); i++)
+	{
+	  buffer += "<xi:include href=\"";
+	  buffer += xml;
+	  buffer += "\"/>";
+	}
+
+      buffer += "</target>";
+
+      tdesc->xmltarget = xstrdup (buffer.c_str ());
+    }
+
+  return tdesc->xmltarget;
+}
 #endif
 
 struct tdesc_type
@@ -69,8 +125,12 @@ struct tdesc_type
 /* See arch/tdesc.h.  */
 
 struct tdesc_feature *
-tdesc_create_feature (struct target_desc *tdesc, const char *name)
+tdesc_create_feature (struct target_desc *tdesc, const char *name,
+		      const char *xml)
 {
+#ifndef IN_PROCESS_AGENT
+  VEC_safe_push (char_ptr, tdesc->features, xstrdup (xml));
+#endif
   return tdesc;
 }