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.

15 files changed, 150 insertions, 39 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 8413504..0ac42e4 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,18 @@
 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.
+
+2017-09-05  Yao Qi  <yao.qi@linaro.org>
+
 	* regformats/regdef.h (struct reg): Override operator == and !=.
 
 2017-09-05  Yao Qi  <yao.qi@linaro.org>
diff --git a/gdb/arch/tdesc.h b/gdb/arch/tdesc.h
index 872df68..bf50e24 100644
--- a/gdb/arch/tdesc.h
+++ b/gdb/arch/tdesc.h
@@ -30,7 +30,9 @@ struct tdesc_type *tdesc_named_type (const struct tdesc_feature *feature,
 
 /* Return the created feature named NAME in target description TDESC.  */
 struct tdesc_feature *tdesc_create_feature (struct target_desc *tdesc,
-					    const char *name);
+					    const char *name,
+					    const char *xml = nullptr);
+
 
 /* Return the created vector tdesc_type named NAME in FEATURE.  */
 struct tdesc_type *tdesc_create_vector (struct tdesc_feature *feature,
diff --git a/gdb/features/i386/32bit-avx.c b/gdb/features/i386/32bit-avx.c
index 3a98936..8a0c356 100644
--- a/gdb/features/i386/32bit-avx.c
+++ b/gdb/features/i386/32bit-avx.c
@@ -8,7 +8,7 @@ create_feature_i386_32bit_avx (struct target_desc *result, long regnum)
 {
   struct tdesc_feature *feature;
 
-  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.avx");
+  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.avx", "32bit-avx.xml");
   tdesc_create_reg (feature, "ymm0h", regnum++, 1, NULL, 128, "uint128");
   tdesc_create_reg (feature, "ymm1h", regnum++, 1, NULL, 128, "uint128");
   tdesc_create_reg (feature, "ymm2h", regnum++, 1, NULL, 128, "uint128");
diff --git a/gdb/features/i386/32bit-avx512.c b/gdb/features/i386/32bit-avx512.c
index b13e1d3..82b20c5 100644
--- a/gdb/features/i386/32bit-avx512.c
+++ b/gdb/features/i386/32bit-avx512.c
@@ -8,7 +8,7 @@ create_feature_i386_32bit_avx512 (struct target_desc *result, long regnum)
 {
   struct tdesc_feature *feature;
 
-  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.avx512");
+  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.avx512", "32bit-avx512.xml");
   struct tdesc_type *field_type;
   field_type = tdesc_named_type (feature, "uint128");
   tdesc_create_vector (feature, "v2ui128", field_type, 2);
diff --git a/gdb/features/i386/32bit-core.c b/gdb/features/i386/32bit-core.c
index ea6db93..ec903f3 100644
--- a/gdb/features/i386/32bit-core.c
+++ b/gdb/features/i386/32bit-core.c
@@ -8,7 +8,7 @@ create_feature_i386_32bit_core (struct target_desc *result, long regnum)
 {
   struct tdesc_feature *feature;
 
-  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.core");
+  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.core", "32bit-core.xml");
   struct tdesc_type *field_type;
   struct tdesc_type *type;
   type = tdesc_create_flags (feature, "i386_eflags", 4);
diff --git a/gdb/features/i386/32bit-linux.c b/gdb/features/i386/32bit-linux.c
index 1ba932d..136e3d7 100644
--- a/gdb/features/i386/32bit-linux.c
+++ b/gdb/features/i386/32bit-linux.c
@@ -8,7 +8,7 @@ create_feature_i386_32bit_linux (struct target_desc *result, long regnum)
 {
   struct tdesc_feature *feature;
 
-  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.linux");
+  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.linux", "32bit-linux.xml");
   regnum = 41;
   tdesc_create_reg (feature, "orig_eax", regnum++, 1, NULL, 32, "int");
   return regnum;
diff --git a/gdb/features/i386/32bit-mpx.c b/gdb/features/i386/32bit-mpx.c
index f7d2ef0..25a3fb1 100644
--- a/gdb/features/i386/32bit-mpx.c
+++ b/gdb/features/i386/32bit-mpx.c
@@ -8,7 +8,7 @@ create_feature_i386_32bit_mpx (struct target_desc *result, long regnum)
 {
   struct tdesc_feature *feature;
 
-  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.mpx");
+  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.mpx", "32bit-mpx.xml");
   struct tdesc_type *field_type;
   struct tdesc_type *type;
   type = tdesc_create_struct (feature, "br128");
diff --git a/gdb/features/i386/32bit-pkeys.c b/gdb/features/i386/32bit-pkeys.c
index 89f1a5b..4ad7649 100644
--- a/gdb/features/i386/32bit-pkeys.c
+++ b/gdb/features/i386/32bit-pkeys.c
@@ -8,7 +8,7 @@ create_feature_i386_32bit_pkeys (struct target_desc *result, long regnum)
 {
   struct tdesc_feature *feature;
 
-  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.pkeys");
+  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.pkeys", "32bit-pkeys.xml");
   tdesc_create_reg (feature, "pkru", regnum++, 1, NULL, 32, "uint32");
   return regnum;
 }
diff --git a/gdb/features/i386/32bit-sse.c b/gdb/features/i386/32bit-sse.c
index 98f4cd0..01b2058 100644
--- a/gdb/features/i386/32bit-sse.c
+++ b/gdb/features/i386/32bit-sse.c
@@ -8,7 +8,7 @@ create_feature_i386_32bit_sse (struct target_desc *result, long regnum)
 {
   struct tdesc_feature *feature;
 
-  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.sse");
+  feature = tdesc_create_feature (result, "org.gnu.gdb.i386.sse", "32bit-sse.xml");
   struct tdesc_type *field_type;
   field_type = tdesc_named_type (feature, "ieee_single");
   tdesc_create_vector (feature, "v4f", field_type, 4);
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 20a0c97..595faf5 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,5 +1,24 @@
 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.
+
+2017-09-05  Yao Qi  <yao.qi@linaro.org>
+
 	* linux-x86-tdesc.c: Include selftest.h.
 	(i386_tdesc_test): New function.
 	(initialize_low_tdesc): Call selftests::register_test.
diff --git a/gdb/gdbserver/linux-x86-tdesc.c b/gdb/gdbserver/linux-x86-tdesc.c
index 1f3dbaf..3f63d8e 100644
--- a/gdb/gdbserver/linux-x86-tdesc.c
+++ b/gdb/gdbserver/linux-x86-tdesc.c
@@ -21,7 +21,6 @@
 #include "tdesc.h"
 #include "linux-x86-tdesc.h"
 #include "x86-xstate.h"
-#include <inttypes.h>
 
 #if defined __i386__ || !defined IN_PROCESS_AGENT
 #include "../features/i386/32bit-core.c"
@@ -145,6 +144,11 @@ i386_linux_read_description (uint64_t xcr0)
     {
       *tdesc = new target_desc ();
 
+#ifndef IN_PROCESS_AGENT
+      set_tdesc_architecture (*tdesc, "i386");
+      set_tdesc_osabi (*tdesc, "GNU/Linux");
+#endif
+
       long regnum = 0;
 
       if (xcr0 & X86_XSTATE_X87)
@@ -172,24 +176,6 @@ i386_linux_read_description (uint64_t xcr0)
 #ifndef IN_PROCESS_AGENT
       static const char *expedite_regs_i386[] = { "ebp", "esp", "eip", NULL };
       (*tdesc)->expedite_regs = expedite_regs_i386;
-
-      if (xcr0 & X86_XSTATE_PKRU)
-	(*tdesc)->xmltarget = "i386-avx-mpx-avx512-pku-linux.xml";
-      else if (xcr0 & X86_XSTATE_AVX512)
-	(*tdesc)->xmltarget = "i386-avx-avx512-linux.xml";
-      else if ((xcr0 & X86_XSTATE_AVX_MPX_MASK) == X86_XSTATE_AVX_MPX_MASK)
-	(*tdesc)->xmltarget = "i386-avx-mpx-linux.xml";
-      else if (xcr0 & X86_XSTATE_MPX)
-	(*tdesc)->xmltarget = "i386-mpx-linux.xml";
-      else if (xcr0 & X86_XSTATE_AVX)
-	(*tdesc)->xmltarget = "i386-avx-linux.xml";
-      else if (xcr0 & X86_XSTATE_SSE)
-	(*tdesc)->xmltarget = "i386-linux.xml";
-      else if (xcr0 & X86_XSTATE_X87)
-	(*tdesc)->xmltarget = "i386-mmx-linux.xml";
-      else
-	internal_error (__FILE__, __LINE__,
-			"unknown xcr0: %" PRIu64, xcr0);
 #endif
     }
 
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index 7210d1f..56c6393 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -873,12 +873,14 @@ get_features_xml (const char *annex)
      This variable is set up from the auto-generated
      init_registers_... routine for the current target.  */
 
-  if (desc->xmltarget != NULL && strcmp (annex, "target.xml") == 0)
+  if (strcmp (annex, "target.xml") == 0)
     {
-      if (*desc->xmltarget == '@')
-	return desc->xmltarget + 1;
+      const char *ret = tdesc_get_features_xml ((target_desc*) desc);
+
+      if (*ret == '@')
+	return ret + 1;
       else
-	annex = desc->xmltarget;
+	annex = ret;
     }
 
 #ifdef USE_XML
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;
 }
 
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 */
diff --git a/gdb/target-descriptions.c b/gdb/target-descriptions.c
index f0ced66..6135e0d 100644
--- a/gdb/target-descriptions.c
+++ b/gdb/target-descriptions.c
@@ -1750,7 +1750,8 @@ tdesc_add_enum_value (struct tdesc_type *type, int value,
 /* 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)
 {
   struct tdesc_feature *new_feature = new tdesc_feature (name);
 
@@ -2202,8 +2203,10 @@ public:
 
     printf_unfiltered ("{\n");
     printf_unfiltered ("  struct tdesc_feature *feature;\n");
-    printf_unfiltered ("\n  feature = tdesc_create_feature (result, \"%s\");\n",
-		       e->name);
+
+    printf_unfiltered
+      ("\n  feature = tdesc_create_feature (result, \"%s\", \"%s\");\n",
+       e->name, lbasename (m_filename_after_features.c_str ()));
   }
 
   void visit_post (const tdesc_feature *e) override