[GOMP] a struct for offload target data

[Nathan Sidwell <nathan at acm dot org>]

Bernd,
this patch changes the offload target data type from an array of void *, to a 
struct, which is somewhat easier to deal with than remembering numeric indices 
and type casts.

This is step  1 in reworking the launch API.

ok?

nathan

2015-07-13  Nathan Sidwell  <nathan@acm.org>

	gcc/
	* config/nvptx/mkoffload.c (process): Constify mapping variables.
	Define target data struct and initialize it.

	libgomp/
	* plugin/plugin-nvptx.c (link_ptx): Constify string argument.
	Workaround driver library const error.
	(struct nvptx_tdata, nvptx_tdata_t): New.
	(GOMP_OFFLOAD_load_image): Use struct for target_data's real
	type.

Index: gcc/config/nvptx/mkoffload.c
===================================================================
--- gcc/config/nvptx/mkoffload.c	(revision 225703)
+++ gcc/config/nvptx/mkoffload.c	(working copy)
@@ -267,22 +267,30 @@ process (FILE *in, FILE *out)
     }
   fprintf (out, "\";\n\n");
 
-  unsigned int nvars = 0, nfuncs = 0;
-
-  fprintf (out, "static const char *var_mappings[] = {\n");
-  for (id_map *id = var_ids; id; id = id->next, nvars++)
+  fprintf (out, "static const char *const var_mappings[] = {\n");
+  for (id_map *id = var_ids; id; id = id->next)
     fprintf (out, "\t\"%s\"%s\n", id->ptx_name, id->next ? "," : "");
   fprintf (out, "};\n\n");
-  fprintf (out, "static const char *func_mappings[] = {\n");
-  for (id_map *id = func_ids; id; id = id->next, nfuncs++)
+  fprintf (out, "static const char *const func_mappings[] = {\n");
+  for (id_map *id = func_ids; id; id = id->next)
     fprintf (out, "\t\"%s\"%s\n", id->ptx_name, id->next ? "," : "");
   fprintf (out, "};\n\n");
 
-  fprintf (out, "static const void *target_data[] = {\n");
-  fprintf (out, "  ptx_code, (void *)(__UINTPTR_TYPE__)sizeof (ptx_code),\n");
-  fprintf (out, "  (void *) %u, var_mappings, (void *) %u, func_mappings\n",
-	   nvars, nfuncs);
-  fprintf (out, "};\n\n");
+  fprintf (out,
+	   "static struct nvptx_tdata {\n"
+	   "  const char *ptx_src;\n"
+	   "  __SIZE_TYPE__ ptx_len;\n"
+	   "  const char *const *var_names;\n"
+	   "  __SIZE_TYPE__ var_num;\n"
+	   "  const char *const *fn_names;\n"
+	   "  __SIZE_TYPE__ fn_num;\n"
+	   "} target_data = {\n"
+	   "  ptx_code, sizeof (ptx_code),\n"
+	   "  var_mappings,"
+	   "  sizeof (var_mappings) / sizeof (var_mappings[0]),\n"
+	   "  func_mappings,"
+	   "  sizeof (func_mappings) / sizeof (func_mappings[0])\n"
+	   "};\n\n");
 
   fprintf (out, "#ifdef __cplusplus\n");
   fprintf (out, "extern \"C\" {\n");
Index: libgomp/plugin/plugin-nvptx.c
===================================================================
--- libgomp/plugin/plugin-nvptx.c	(revision 225703)
+++ libgomp/plugin/plugin-nvptx.c	(working copy)
@@ -798,7 +798,7 @@ nvptx_get_num_devices (void)
 
 
 static void
-link_ptx (CUmodule *module, char *ptx_code, size_t length)
+link_ptx (CUmodule *module, char const *ptx_code, size_t length)
 {
   CUjit_option opts[7];
   void *optvals[7];
@@ -843,7 +843,9 @@ link_ptx (CUmodule *module, char *ptx_co
   while (off < length)
     {
       int l = strlen (ptx_code + off);
-      r = cuLinkAddData (linkstate, CU_JIT_INPUT_PTX, ptx_code + off, l + 1,
+      /* cuLinkAddData's 'data' argument erroneously omits the const
+	 qualifier.  */
+      r = cuLinkAddData (linkstate, CU_JIT_INPUT_PTX, (char*)ptx_code + off, l + 1,
 			 0, 0, 0, 0);
       if (r != CUDA_SUCCESS)
 	{
@@ -1580,23 +1582,35 @@ GOMP_OFFLOAD_fini_device (int n)
   pthread_mutex_unlock (&ptx_dev_lock);
 }
 
+typedef struct nvptx_tdata
+{
+  const char *ptx_src;
+  size_t ptx_len;
+
+  const char *const *var_names;
+  size_t var_num;
+
+  const char *const *fn_names;
+  size_t fn_num;
+} nvptx_tdata_t;
+
 int
 GOMP_OFFLOAD_load_image (int ord, void *target_data,
 			 struct addr_pair **target_table)
 {
   CUmodule module;
-  char **fn_names, **var_names;
+  const char *const *fn_names, *const *var_names;
   unsigned int fn_entries, var_entries, i, j;
   CUresult r;
   struct targ_fn_descriptor *targ_fns;
-  void **img_header = (void **) target_data;
+  nvptx_tdata_t const *img_header = (nvptx_tdata_t const *) target_data;
   struct ptx_image_data *new_image;
 
   GOMP_OFFLOAD_init_device (ord);
 
   nvptx_attach_host_thread_to_device (ord);
 
-  link_ptx (&module, img_header[0], (size_t) img_header[1]);
+  link_ptx (&module, img_header->ptx_src, img_header->ptx_len);
 
   pthread_mutex_lock (&ptx_image_lock);
   new_image = GOMP_PLUGIN_malloc (sizeof (struct ptx_image_data));
@@ -1606,23 +1620,15 @@ GOMP_OFFLOAD_load_image (int ord, void *
   ptx_images = new_image;
   pthread_mutex_unlock (&ptx_image_lock);
 
-  /* The mkoffload utility emits a table of pointers/integers at the start of
-     each offload image:
-
-     img_header[0] -> ptx code
-     img_header[1] -> size of ptx code
-     img_header[2] -> number of variables
-     img_header[3] -> array of variable names (pointers to strings)
-     img_header[4] -> number of kernels
-     img_header[5] -> array of kernel names (pointers to strings)
-
-     The array of kernel names and the functions addresses form a
-     one-to-one correspondence.  */
-
-  var_entries = (uintptr_t) img_header[2];
-  var_names = (char **) img_header[3];
-  fn_entries = (uintptr_t) img_header[4];
-  fn_names = (char **) img_header[5];
+  
+  /* The mkoffload utility emits a struct of pointers/integers at the
+     start of each offload image.  The array of kernel names and the
+     functions addresses form a one-to-one correspondence.  */
+
+  var_entries = img_header->var_num;
+  var_names = img_header->var_names;
+  fn_entries = img_header->fn_num;
+  fn_names = img_header->fn_names;
 
   *target_table = GOMP_PLUGIN_malloc (sizeof (struct addr_pair)
 				      * (fn_entries + var_entries));