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, 30 insertions, 4 deletions

diff --git a/gdb/gdbserver/tdesc.h b/gdb/gdbserver/tdesc.h
index 49c82c6..fe3c78f 100644
--- a/gdb/gdbserver/tdesc.h
+++ b/gdb/gdbserver/tdesc.h
@@ -49,9 +49,21 @@ struct target_desc : tdesc_feature
   /* Defines what to return when looking for the "target.xml" file in
      response to qXfer:features:read.  Its contents can either be
      verbatim XML code (prefixed with a '@') or else the name of the
-     actual XML file to be used in place of "target.xml".  */
+     actual XML file to be used in place of "target.xml".
+
+     It can be NULL, then, its content is got from the following three
+     fields features, arch, and osabi in tdesc_get_features_xml.  */
   const char *xmltarget = NULL;
 
+  /* XML features in this target description.  */
+  VEC (char_ptr) *features = NULL;
+
+  /* The value of <architecture> element in the XML, replying GDB.  */
+  const char *arch = NULL;
+
+  /* The value of <osabi> element in the XML, replying GDB.  */
+  const char *osabi = NULL;
+
 public:
   target_desc ()
     : reg_defs (NULL), registers_size (0)
@@ -65,6 +77,15 @@ public:
     for (i = 0; VEC_iterate (tdesc_reg_p, reg_defs, i, reg); i++)
       xfree (reg);
     VEC_free (tdesc_reg_p, reg_defs);
+
+    xfree ((char *) arch);
+    xfree ((char *) osabi);
+
+    char *f;
+
+    for (i = 0; VEC_iterate (char_ptr, features, i, f); i++)
+      xfree (f);
+    VEC_free (char_ptr, features);
   }
 
   bool operator== (const target_desc &other) const
@@ -96,9 +117,6 @@ public:
     if (other.expedite_regs[i] != NULL)
       return false;
 
-    if (strcmp (xmltarget, other.xmltarget) != 0)
-      return false;
-
     return true;
   }
 
@@ -123,4 +141,12 @@ void init_target_desc (struct target_desc *tdesc);
 
 const struct target_desc *current_target_desc (void);
 
+#ifndef IN_PROCESS_AGENT
+void set_tdesc_architecture (struct target_desc *target_desc,
+			     const char *name);
+void set_tdesc_osabi (struct target_desc *target_desc, const char *name);
+
+const char *tdesc_get_features_xml (struct target_desc *tdesc);
+#endif
+
 #endif /* TDESC_H */