1 //===----------- api.cpp - Target independent OpenMP target RTL -----------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Implementation of OpenMP API interface functions.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include <omptarget.h>
14 
15 #include "device.h"
16 #include "private.h"
17 #include "rtl.h"
18 
19 #include <climits>
20 #include <cstring>
21 #include <cstdlib>
22 
23 EXTERN int omp_get_num_devices(void) {
24   RTLsMtx->lock();
25   size_t Devices_size = Devices.size();
26   RTLsMtx->unlock();
27 
28   DP("Call to omp_get_num_devices returning %zd\n", Devices_size);
29 
30   return Devices_size;
31 }
32 
33 EXTERN int omp_get_initial_device(void) {
34   DP("Call to omp_get_initial_device returning %d\n", HOST_DEVICE);
35   return HOST_DEVICE;
36 }
37 
38 EXTERN void *omp_target_alloc(size_t size, int device_num) {
39   DP("Call to omp_target_alloc for device %d requesting %zu bytes\n",
40       device_num, size);
41 
42   if (size <= 0) {
43     DP("Call to omp_target_alloc with non-positive length\n");
44     return NULL;
45   }
46 
47   void *rc = NULL;
48 
49   if (device_num == omp_get_initial_device()) {
50     rc = malloc(size);
51     DP("omp_target_alloc returns host ptr " DPxMOD "\n", DPxPTR(rc));
52     return rc;
53   }
54 
55   if (!device_is_ready(device_num)) {
56     DP("omp_target_alloc returns NULL ptr\n");
57     return NULL;
58   }
59 
60   DeviceTy &Device = Devices[device_num];
61   rc = Device.RTL->data_alloc(Device.RTLDeviceID, size, NULL);
62   DP("omp_target_alloc returns device ptr " DPxMOD "\n", DPxPTR(rc));
63   return rc;
64 }
65 
66 EXTERN void omp_target_free(void *device_ptr, int device_num) {
67   DP("Call to omp_target_free for device %d and address " DPxMOD "\n",
68       device_num, DPxPTR(device_ptr));
69 
70   if (!device_ptr) {
71     DP("Call to omp_target_free with NULL ptr\n");
72     return;
73   }
74 
75   if (device_num == omp_get_initial_device()) {
76     free(device_ptr);
77     DP("omp_target_free deallocated host ptr\n");
78     return;
79   }
80 
81   if (!device_is_ready(device_num)) {
82     DP("omp_target_free returns, nothing to do\n");
83     return;
84   }
85 
86   DeviceTy &Device = Devices[device_num];
87   Device.RTL->data_delete(Device.RTLDeviceID, (void *)device_ptr);
88   DP("omp_target_free deallocated device ptr\n");
89 }
90 
91 EXTERN int omp_target_is_present(void *ptr, int device_num) {
92   DP("Call to omp_target_is_present for device %d and address " DPxMOD "\n",
93       device_num, DPxPTR(ptr));
94 
95   if (!ptr) {
96     DP("Call to omp_target_is_present with NULL ptr, returning false\n");
97     return false;
98   }
99 
100   if (device_num == omp_get_initial_device()) {
101     DP("Call to omp_target_is_present on host, returning true\n");
102     return true;
103   }
104 
105   RTLsMtx->lock();
106   size_t Devices_size = Devices.size();
107   RTLsMtx->unlock();
108   if (Devices_size <= (size_t)device_num) {
109     DP("Call to omp_target_is_present with invalid device ID, returning "
110         "false\n");
111     return false;
112   }
113 
114   DeviceTy& Device = Devices[device_num];
115   bool IsLast; // not used
116   bool IsHostPtr;
117   void *TgtPtr = Device.getTgtPtrBegin(ptr, 0, IsLast, false, IsHostPtr);
118   int rc = (TgtPtr != NULL);
119   // Under unified memory the host pointer can be returned by the
120   // getTgtPtrBegin() function which means that there is no device
121   // corresponding point for ptr. This function should return false
122   // in that situation.
123   if (RTLs->RequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY)
124     rc = !IsHostPtr;
125   DP("Call to omp_target_is_present returns %d\n", rc);
126   return rc;
127 }
128 
129 EXTERN int omp_target_memcpy(void *dst, void *src, size_t length,
130     size_t dst_offset, size_t src_offset, int dst_device, int src_device) {
131   DP("Call to omp_target_memcpy, dst device %d, src device %d, "
132       "dst addr " DPxMOD ", src addr " DPxMOD ", dst offset %zu, "
133       "src offset %zu, length %zu\n", dst_device, src_device, DPxPTR(dst),
134       DPxPTR(src), dst_offset, src_offset, length);
135 
136   if (!dst || !src || length <= 0) {
137     DP("Call to omp_target_memcpy with invalid arguments\n");
138     return OFFLOAD_FAIL;
139   }
140 
141   if (src_device != omp_get_initial_device() && !device_is_ready(src_device)) {
142       DP("omp_target_memcpy returns OFFLOAD_FAIL\n");
143       return OFFLOAD_FAIL;
144   }
145 
146   if (dst_device != omp_get_initial_device() && !device_is_ready(dst_device)) {
147       DP("omp_target_memcpy returns OFFLOAD_FAIL\n");
148       return OFFLOAD_FAIL;
149   }
150 
151   int rc = OFFLOAD_SUCCESS;
152   void *srcAddr = (char *)src + src_offset;
153   void *dstAddr = (char *)dst + dst_offset;
154 
155   if (src_device == omp_get_initial_device() &&
156       dst_device == omp_get_initial_device()) {
157     DP("copy from host to host\n");
158     const void *p = memcpy(dstAddr, srcAddr, length);
159     if (p == NULL)
160       rc = OFFLOAD_FAIL;
161   } else if (src_device == omp_get_initial_device()) {
162     DP("copy from host to device\n");
163     DeviceTy& DstDev = Devices[dst_device];
164     rc = DstDev.data_submit(dstAddr, srcAddr, length, nullptr);
165   } else if (dst_device == omp_get_initial_device()) {
166     DP("copy from device to host\n");
167     DeviceTy& SrcDev = Devices[src_device];
168     rc = SrcDev.data_retrieve(dstAddr, srcAddr, length, nullptr);
169   } else {
170     DP("copy from device to device\n");
171     void *buffer = malloc(length);
172     DeviceTy& SrcDev = Devices[src_device];
173     DeviceTy& DstDev = Devices[dst_device];
174     rc = SrcDev.data_retrieve(buffer, srcAddr, length, nullptr);
175     if (rc == OFFLOAD_SUCCESS)
176       rc = DstDev.data_submit(dstAddr, buffer, length, nullptr);
177     free(buffer);
178   }
179 
180   DP("omp_target_memcpy returns %d\n", rc);
181   return rc;
182 }
183 
184 EXTERN int omp_target_memcpy_rect(void *dst, void *src, size_t element_size,
185     int num_dims, const size_t *volume, const size_t *dst_offsets,
186     const size_t *src_offsets, const size_t *dst_dimensions,
187     const size_t *src_dimensions, int dst_device, int src_device) {
188   DP("Call to omp_target_memcpy_rect, dst device %d, src device %d, "
189       "dst addr " DPxMOD ", src addr " DPxMOD ", dst offsets " DPxMOD ", "
190       "src offsets " DPxMOD ", dst dims " DPxMOD ", src dims " DPxMOD ", "
191       "volume " DPxMOD ", element size %zu, num_dims %d\n", dst_device,
192       src_device, DPxPTR(dst), DPxPTR(src), DPxPTR(dst_offsets),
193       DPxPTR(src_offsets), DPxPTR(dst_dimensions), DPxPTR(src_dimensions),
194       DPxPTR(volume), element_size, num_dims);
195 
196   if (!(dst || src)) {
197     DP("Call to omp_target_memcpy_rect returns max supported dimensions %d\n",
198         INT_MAX);
199     return INT_MAX;
200   }
201 
202   if (!dst || !src || element_size < 1 || num_dims < 1 || !volume ||
203       !dst_offsets || !src_offsets || !dst_dimensions || !src_dimensions) {
204     DP("Call to omp_target_memcpy_rect with invalid arguments\n");
205     return OFFLOAD_FAIL;
206   }
207 
208   int rc;
209   if (num_dims == 1) {
210     rc = omp_target_memcpy(dst, src, element_size * volume[0],
211         element_size * dst_offsets[0], element_size * src_offsets[0],
212         dst_device, src_device);
213   } else {
214     size_t dst_slice_size = element_size;
215     size_t src_slice_size = element_size;
216     for (int i=1; i<num_dims; ++i) {
217       dst_slice_size *= dst_dimensions[i];
218       src_slice_size *= src_dimensions[i];
219     }
220 
221     size_t dst_off = dst_offsets[0] * dst_slice_size;
222     size_t src_off = src_offsets[0] * src_slice_size;
223     for (size_t i=0; i<volume[0]; ++i) {
224       rc = omp_target_memcpy_rect((char *) dst + dst_off + dst_slice_size * i,
225           (char *) src + src_off + src_slice_size * i, element_size,
226           num_dims - 1, volume + 1, dst_offsets + 1, src_offsets + 1,
227           dst_dimensions + 1, src_dimensions + 1, dst_device, src_device);
228 
229       if (rc) {
230         DP("Recursive call to omp_target_memcpy_rect returns unsuccessfully\n");
231         return rc;
232       }
233     }
234   }
235 
236   DP("omp_target_memcpy_rect returns %d\n", rc);
237   return rc;
238 }
239 
240 EXTERN int omp_target_associate_ptr(void *host_ptr, void *device_ptr,
241     size_t size, size_t device_offset, int device_num) {
242   DP("Call to omp_target_associate_ptr with host_ptr " DPxMOD ", "
243       "device_ptr " DPxMOD ", size %zu, device_offset %zu, device_num %d\n",
244       DPxPTR(host_ptr), DPxPTR(device_ptr), size, device_offset, device_num);
245 
246   if (!host_ptr || !device_ptr || size <= 0) {
247     DP("Call to omp_target_associate_ptr with invalid arguments\n");
248     return OFFLOAD_FAIL;
249   }
250 
251   if (device_num == omp_get_initial_device()) {
252     DP("omp_target_associate_ptr: no association possible on the host\n");
253     return OFFLOAD_FAIL;
254   }
255 
256   if (!device_is_ready(device_num)) {
257     DP("omp_target_associate_ptr returns OFFLOAD_FAIL\n");
258     return OFFLOAD_FAIL;
259   }
260 
261   DeviceTy& Device = Devices[device_num];
262   void *device_addr = (void *)((uint64_t)device_ptr + (uint64_t)device_offset);
263   int rc = Device.associatePtr(host_ptr, device_addr, size);
264   DP("omp_target_associate_ptr returns %d\n", rc);
265   return rc;
266 }
267 
268 EXTERN int omp_target_disassociate_ptr(void *host_ptr, int device_num) {
269   DP("Call to omp_target_disassociate_ptr with host_ptr " DPxMOD ", "
270       "device_num %d\n", DPxPTR(host_ptr), device_num);
271 
272   if (!host_ptr) {
273     DP("Call to omp_target_associate_ptr with invalid host_ptr\n");
274     return OFFLOAD_FAIL;
275   }
276 
277   if (device_num == omp_get_initial_device()) {
278     DP("omp_target_disassociate_ptr: no association possible on the host\n");
279     return OFFLOAD_FAIL;
280   }
281 
282   if (!device_is_ready(device_num)) {
283     DP("omp_target_disassociate_ptr returns OFFLOAD_FAIL\n");
284     return OFFLOAD_FAIL;
285   }
286 
287   DeviceTy& Device = Devices[device_num];
288   int rc = Device.disassociatePtr(host_ptr);
289   DP("omp_target_disassociate_ptr returns %d\n", rc);
290   return rc;
291 }
292