[PATCH v2 5/8] Windows gdb: Prepare XState functions

These functions will then be used to access the XState registers.
---
 gdb/nat/windows-nat.c |  31 +++++++++++
 gdb/nat/windows-nat.h | 116 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 147 insertions(+)

diff --git a/gdb/nat/windows-nat.c b/gdb/nat/windows-nat.c
index 689601f3a82..cd1f9e7bc64 100644
--- a/gdb/nat/windows-nat.c
+++ b/gdb/nat/windows-nat.c
@@ -73,6 +73,19 @@ InitializeProcThreadAttributeList_ftype *InitializeProcThreadAttributeList;
 UpdateProcThreadAttribute_ftype *UpdateProcThreadAttribute;
 DeleteProcThreadAttributeList_ftype *DeleteProcThreadAttributeList;
 
+#if defined __i386__ || defined __x86_64__
+GetEnabledXStateFeatures_ftype *GetEnabledXStateFeatures;
+InitializeContext_ftype *InitializeContext;
+GetXStateFeaturesMask_ftype *GetXStateFeaturesMask;
+SetXStateFeaturesMask_ftype *SetXStateFeaturesMask;
+LocateXStateFeature_ftype *LocateXStateFeature;
+#ifdef __x86_64__
+RtlGetExtendedFeaturesMask_ftype *RtlGetExtendedFeaturesMask;
+RtlSetExtendedFeaturesMask_ftype *RtlSetExtendedFeaturesMask;
+RtlLocateExtendedFeature_ftype *RtlLocateExtendedFeature;
+#endif
+#endif
+
 /* Note that 'debug_events' must be locally defined in the relevant
    functions.  */
 #define DEBUG_EVENTS(fmt, ...) \
@@ -1191,6 +1204,14 @@ initialize_loadable ()
       GPA (hm, InitializeProcThreadAttributeList);
       GPA (hm, UpdateProcThreadAttribute);
       GPA (hm, DeleteProcThreadAttributeList);
+
+#if defined __i386__ || defined __x86_64__
+      GPA (hm, GetEnabledXStateFeatures);
+      GPA (hm, InitializeContext);
+      GPA (hm, GetXStateFeaturesMask);
+      GPA (hm, SetXStateFeaturesMask);
+      GPA (hm, LocateXStateFeature);
+#endif
     }
 
   /* Set variables to dummy versions of these processes if the function
@@ -1256,6 +1277,16 @@ initialize_loadable ()
 	GPA (hm, GetThreadDescription);
     }
 
+#ifdef __x86_64__
+  hm = LoadLibrary (TEXT ("ntdll.dll"));
+  if (hm)
+    {
+      GPA (hm, RtlGetExtendedFeaturesMask);
+      GPA (hm, RtlSetExtendedFeaturesMask);
+      GPA (hm, RtlLocateExtendedFeature);
+    }
+#endif
+
 #undef GPA
 
   return result;
diff --git a/gdb/nat/windows-nat.h b/gdb/nat/windows-nat.h
index 76688fa90da..a344b0a966f 100644
--- a/gdb/nat/windows-nat.h
+++ b/gdb/nat/windows-nat.h
@@ -35,6 +35,9 @@
 #define CONTEXT_EXTENDED_REGISTERS 0
 #endif
 
+#define CONTEXT_EXTENDED_REGISTERS_FLAG	0x20
+#define CONTEXT_XSTATE_FLAG		0x40
+
 namespace windows_nat
 {
 
@@ -456,6 +459,14 @@ extern BOOL create_process (const wchar_t *image, wchar_t *command_line,
 #define InitializeProcThreadAttributeList dyn_InitializeProcThreadAttributeList
 #define UpdateProcThreadAttribute dyn_UpdateProcThreadAttribute
 #define DeleteProcThreadAttributeList dyn_DeleteProcThreadAttributeList
+#define GetEnabledXStateFeatures	dyn_GetEnabledXStateFeatures
+#define InitializeContext		dyn_InitializeContext
+#define GetXStateFeaturesMask		dyn_GetXStateFeaturesMask
+#define SetXStateFeaturesMask		dyn_SetXStateFeaturesMask
+#define LocateXStateFeature		dyn_LocateXStateFeature
+#define RtlGetExtendedFeaturesMask	dyn_RtlGetExtendedFeaturesMask
+#define RtlSetExtendedFeaturesMask	dyn_RtlSetExtendedFeaturesMask
+#define RtlLocateExtendedFeature	dyn_RtlLocateExtendedFeature
 
 typedef BOOL WINAPI (AdjustTokenPrivileges_ftype) (HANDLE, BOOL,
 						   PTOKEN_PRIVILEGES,
@@ -550,6 +561,35 @@ extern DeleteProcThreadAttributeList_ftype *DeleteProcThreadAttributeList;
 
 extern bool disable_randomization_available ();
 
+#if defined __i386__ || defined __x86_64__
+typedef DWORD64 (WINAPI GetEnabledXStateFeatures_ftype) ();
+extern GetEnabledXStateFeatures_ftype *GetEnabledXStateFeatures;
+
+typedef BOOL (WINAPI InitializeContext_ftype) (PVOID, DWORD,
+					       PCONTEXT*, PDWORD);
+extern InitializeContext_ftype *InitializeContext;
+
+typedef BOOL (WINAPI GetXStateFeaturesMask_ftype) (PCONTEXT, PDWORD64);
+extern GetXStateFeaturesMask_ftype *GetXStateFeaturesMask;
+
+typedef BOOL (WINAPI SetXStateFeaturesMask_ftype) (PCONTEXT, DWORD64);
+extern SetXStateFeaturesMask_ftype *SetXStateFeaturesMask;
+
+typedef PVOID (WINAPI LocateXStateFeature_ftype) (PCONTEXT, DWORD, PDWORD);
+extern LocateXStateFeature_ftype *LocateXStateFeature;
+
+#ifdef __x86_64__
+typedef DWORD64 (WINAPI RtlGetExtendedFeaturesMask_ftype) (PVOID);
+extern RtlGetExtendedFeaturesMask_ftype *RtlGetExtendedFeaturesMask;
+
+typedef VOID (WINAPI RtlSetExtendedFeaturesMask_ftype) (PVOID, DWORD64);
+extern RtlSetExtendedFeaturesMask_ftype *RtlSetExtendedFeaturesMask;
+
+typedef PVOID (WINAPI RtlLocateExtendedFeature_ftype) (PVOID, DWORD, PDWORD);
+extern RtlLocateExtendedFeature_ftype *RtlLocateExtendedFeature;
+#endif
+#endif
+
 /* Helper classes to get the correct ContextFlags values based on the
    used type (CONTEXT or WOW64_CONTEXT).  */
 
@@ -615,16 +655,69 @@ enum_process_modules (CONTEXT *, HANDLE process,
   return EnumProcessModules (process, modules, size, needed);
 }
 
+#if defined __i386__ || defined __x86_64__
+static inline BOOL
+get_xstate_features_mask (CONTEXT *context, DWORD64 *mask)
+{
+  return GetXStateFeaturesMask (context, mask);
+}
+
+static inline BOOL
+set_xstate_features_mask (CONTEXT *context, DWORD64 mask)
+{
+  return SetXStateFeaturesMask (context, mask);
+}
+
+static inline PVOID
+locate_xstate_feature (CONTEXT *context, DWORD feature, DWORD *length)
+{
+  return LocateXStateFeature (context, feature, length);
+}
+#endif
+
 #ifdef __x86_64__
 static inline BOOL
 get_thread_context (HANDLE h, WOW64_CONTEXT *context)
 {
+  if ((context->ContextFlags & CONTEXT_XSTATE_FLAG) != 0)
+    {
+      /* Wow64GetThreadContext doesn't handle CONTEXT_EXTENDED_REGISTERS and
+	 CONTEXT_XSTATE combined correctly, but separate they work fine.  */
+      DWORD flags = context->ContextFlags;
+      context->ContextFlags &= ~CONTEXT_EXTENDED_REGISTERS_FLAG;
+      BOOL ret = Wow64GetThreadContext (h, context);
+      context->ContextFlags = flags;
+      if (!ret)
+	return FALSE;
+
+      context->ContextFlags &= ~CONTEXT_XSTATE_FLAG;
+      ret = Wow64GetThreadContext (h, context);
+      context->ContextFlags = flags;
+      return ret;
+    }
+
   return Wow64GetThreadContext (h, context);
 }
 
 static inline BOOL
 set_thread_context (HANDLE h, WOW64_CONTEXT *context)
 {
+  if ((context->ContextFlags & CONTEXT_XSTATE_FLAG) != 0)
+    {
+      /* Same limitation as Wow64GetThreadContext above.  */
+      DWORD flags = context->ContextFlags;
+      context->ContextFlags &= ~CONTEXT_EXTENDED_REGISTERS_FLAG;
+      BOOL ret = Wow64SetThreadContext (h, context);
+      context->ContextFlags = flags;
+      if (!ret)
+	return FALSE;
+
+      context->ContextFlags &= ~CONTEXT_XSTATE_FLAG;
+      ret = Wow64SetThreadContext (h, context);
+      context->ContextFlags = flags;
+      return ret;
+    }
+
   return Wow64SetThreadContext (h, context);
 }
 
@@ -642,6 +735,29 @@ enum_process_modules (WOW64_CONTEXT *, HANDLE process,
   return EnumProcessModulesEx (process, modules, size, needed,
 			       LIST_MODULES_32BIT);
 }
+
+static inline BOOL
+get_xstate_features_mask (WOW64_CONTEXT *context, DWORD64 *mask)
+{
+  /* Use lower level function, since there is no Wow64GetXStateFeaturesMask.  */
+  *mask = RtlGetExtendedFeaturesMask (context + 1);
+  return TRUE;
+}
+
+static inline BOOL
+set_xstate_features_mask (WOW64_CONTEXT *context, DWORD64 mask)
+{
+  /* Use lower level function, since there is no Wow64SetXStateFeaturesMask.  */
+  RtlSetExtendedFeaturesMask (context + 1, mask);
+  return TRUE;
+}
+
+static inline PVOID
+locate_xstate_feature (WOW64_CONTEXT *context, DWORD feature, DWORD *length)
+{
+  /* Use lower level function, since there is no Wow64LocateXStateFeature.  */
+  return RtlLocateExtendedFeature (context + 1, feature, length);
+}
 #endif
 
 /* This is available starting with Windows 10.  */
-- 
2.54.0