Host-to-device transfer coalescing & magic offset value self-documentation

2018-11-10  Julian Brown  <julian@codesourcery.com>

	libgomp/
	* libgomp.h (OFFSET_INLINED, OFFSET_POINTER, OFFSET_STRUCT): Define.
	* target.c (FIELD_TGT_EMPTY): Define.
	(gomp_map_val): Use OFFSET_* macros instead of magic constants.  Write
	as switch instead of list of ifs.
	(gomp_map_vars_internal): Use OFFSET_* and FIELD_TGT_EMPTY macros.

(cherry picked from openacc-gcc-9-branch commit
dc9711235460a559ab9bafca5f9b4bae155ac798)

diff --git a/libgomp/ChangeLog.omp b/libgomp/ChangeLog.omp
index 83bd8efb1f0a1a84afe0146ec121932ed71899d2..aeeabefb6b00c211bf7bcfc90d43ba3ddb264d53 100644 (file)
--- a/libgomp/ChangeLog.omp
+++ b/libgomp/ChangeLog.omp
@@ -1,3 +1,11 @@
+2018-11-10  Julian Brown  <julian@codesourcery.com>
+
+       * libgomp.h (OFFSET_INLINED, OFFSET_POINTER, OFFSET_STRUCT): Define.
+       * target.c (FIELD_TGT_EMPTY): Define.
+       (gomp_map_val): Use OFFSET_* macros instead of magic constants.  Write
+       as switch instead of list of ifs.
+       (gomp_map_vars_internal): Use OFFSET_* and FIELD_TGT_EMPTY macros.
+
 2019-02-26  Chung-Lin Tang  <cltang@codesourcery.com>
 
        * target.c (goacc_device_copy_async): New function.

diff --git a/libgomp/libgomp.h b/libgomp/libgomp.h
index a83237385f568b78fae9b3fcdee8024bf0104734..884a732c2961baee60591d9887aaf6c01054e57d 100644 (file)
--- a/libgomp/libgomp.h
+++ b/libgomp/libgomp.h
@@ -903,6 +903,11 @@ struct target_mem_desc {
    artificial pointer to "omp declare target link" object.  */
 #define REFCOUNT_LINK (~(uintptr_t) 1)
 
+/* Special offset values.  */
+#define OFFSET_INLINED (~(uintptr_t) 0)
+#define OFFSET_POINTER (~(uintptr_t) 1)
+#define OFFSET_STRUCT (~(uintptr_t) 2)
+
 struct splay_tree_key_s {
   /* Address of the host object.  */
   uintptr_t host_start;

diff --git a/libgomp/target.c b/libgomp/target.c
index 3fff523a3e7453ea494d37678460998331fea1a5..a97af02ebfef7c50792e1e1e14b38e0bb6be2d2e 100644 (file)
--- a/libgomp/target.c
+++ b/libgomp/target.c
@@ -45,6 +45,8 @@
 #include "plugin-suffix.h"
 #endif
 
+#define FIELD_TGT_EMPTY (~(size_t) 0)
+
 static void gomp_target_init (void);
 
 /* The whole initialization code for offloading plugins is only run one.  */
@@ -205,8 +207,8 @@ goacc_device_copy_async (struct gomp_device_descr *devicep,
     }
 }
 
-/* Infrastructure for coalescing adjacent or nearly adjacent (in device addresses)
-   host to device memory transfers.  */
+/* Infrastructure for coalescing adjacent or nearly adjacent (in device
+   addresses) host to device memory transfers.  */
 
 struct gomp_coalesce_chunk
 {
@@ -510,17 +512,25 @@ gomp_map_val (struct target_mem_desc *tgt, void **hostaddrs, size_t i)
     return tgt->list[i].key->tgt->tgt_start
           + tgt->list[i].key->tgt_offset
           + tgt->list[i].offset;
-  if (tgt->list[i].offset == ~(uintptr_t) 0)
-    return (uintptr_t) hostaddrs[i];
-  if (tgt->list[i].offset == ~(uintptr_t) 1)
-    return 0;
-  if (tgt->list[i].offset == ~(uintptr_t) 2)
-    return tgt->list[i + 1].key->tgt->tgt_start
-          + tgt->list[i + 1].key->tgt_offset
-          + tgt->list[i + 1].offset
-          + (uintptr_t) hostaddrs[i]
-          - (uintptr_t) hostaddrs[i + 1];
-  return tgt->tgt_start + tgt->list[i].offset;
+
+  switch (tgt->list[i].offset)
+    {
+    case OFFSET_INLINED:
+      return (uintptr_t) hostaddrs[i];
+
+    case OFFSET_POINTER:
+      return 0;
+
+    case OFFSET_STRUCT:
+      return tgt->list[i + 1].key->tgt->tgt_start
+            + tgt->list[i + 1].key->tgt_offset
+            + tgt->list[i + 1].offset
+            + (uintptr_t) hostaddrs[i]
+            - (uintptr_t) hostaddrs[i + 1];
+
+    default:
+      return tgt->tgt_start + tgt->list[i].offset;
+    }
 }
 
 static inline __attribute__((always_inline)) struct target_mem_desc *
@@ -588,7 +598,7 @@ gomp_map_vars_internal (struct gomp_device_descr *devicep,
          || (kind & typemask) == GOMP_MAP_FIRSTPRIVATE_INT)
        {
          tgt->list[i].key = NULL;
-         tgt->list[i].offset = ~(uintptr_t) 0;
+         tgt->list[i].offset = OFFSET_INLINED;
          continue;
        }
       else if ((kind & typemask) == GOMP_MAP_USE_DEVICE_PTR)
@@ -606,7 +616,7 @@ gomp_map_vars_internal (struct gomp_device_descr *devicep,
            = (void *) (n->tgt->tgt_start + n->tgt_offset
                        + cur_node.host_start);
          tgt->list[i].key = NULL;
-         tgt->list[i].offset = ~(uintptr_t) 0;
+         tgt->list[i].offset = OFFSET_INLINED;
          continue;
        }
       else if ((kind & typemask) == GOMP_MAP_STRUCT)
@@ -617,7 +627,7 @@ gomp_map_vars_internal (struct gomp_device_descr *devicep,
          cur_node.host_end = (uintptr_t) hostaddrs[last]
                              + sizes[last];
          tgt->list[i].key = NULL;
-         tgt->list[i].offset = ~(uintptr_t) 2;
+         tgt->list[i].offset = OFFSET_STRUCT;
          splay_tree_key n = splay_tree_lookup (mem_map, &cur_node);
          if (n == NULL)
            {
@@ -650,7 +660,7 @@ gomp_map_vars_internal (struct gomp_device_descr *devicep,
       else if ((kind & typemask) == GOMP_MAP_ALWAYS_POINTER)
        {
          tgt->list[i].key = NULL;
-         tgt->list[i].offset = ~(uintptr_t) 1;
+         tgt->list[i].offset = OFFSET_POINTER;
          has_firstprivate = true;
          continue;
        }
@@ -680,7 +690,7 @@ gomp_map_vars_internal (struct gomp_device_descr *devicep,
          if (!n)
            {
              tgt->list[i].key = NULL;
-             tgt->list[i].offset = ~(uintptr_t) 1;
+             tgt->list[i].offset = OFFSET_POINTER;
              continue;
            }
        }
@@ -872,6 +882,8 @@ gomp_map_vars_internal (struct gomp_device_descr *devicep,
            else
              k->host_end = k->host_start + sizeof (void *);
            splay_tree_key n = splay_tree_lookup (mem_map, k);
+           /* Need to account for the case where a struct field hasn't been
+              mapped onto the accelerator yet.  */
            if (n && n->refcount != REFCOUNT_LINK)
              gomp_map_vars_existing (devicep, aq, n, k, &tgt->list[i],
                                      kind & typemask, cbufp);
@@ -888,12 +900,12 @@ gomp_map_vars_internal (struct gomp_device_descr *devicep,
                size_t align = (size_t) 1 << (kind >> rshift);
                tgt->list[i].key = k;
                k->tgt = tgt;
-               if (field_tgt_clear != ~(size_t) 0)
+               if (field_tgt_clear != FIELD_TGT_EMPTY)
                  {
                    k->tgt_offset = k->host_start - field_tgt_base
                                    + field_tgt_offset;
                    if (i == field_tgt_clear)
-                     field_tgt_clear = ~(size_t) 0;
+                     field_tgt_clear = FIELD_TGT_EMPTY;
                  }
                else
                  {