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 "device.h"
14 #include "omptarget.h"
15 #include "private.h"
16 #include "rtl.h"
17 
18 #include <climits>
19 #include <cstdlib>
20 #include <cstring>
21 
22 EXTERN int omp_get_num_devices(void) {
23   TIMESCOPE();
24   PM->RTLsMtx.lock();
25   size_t DevicesSize = PM->Devices.size();
26   PM->RTLsMtx.unlock();
27 
28   DP("Call to omp_get_num_devices returning %zd\n", DevicesSize);
29 
30   return DevicesSize;
31 }
32 
33 EXTERN int omp_get_initial_device(void) {
34   TIMESCOPE();
35   int hostDevice = omp_get_num_devices();
36   DP("Call to omp_get_initial_device returning %d\n", hostDevice);
37   return hostDevice;
38 }
39 
40 EXTERN void *omp_target_alloc(size_t size, int device_num) {
41   return targetAllocExplicit(size, device_num, TARGET_ALLOC_DEFAULT, __func__);
42 }
43 
44 EXTERN void *llvm_omp_target_alloc_device(size_t size, int device_num) {
45   return targetAllocExplicit(size, device_num, TARGET_ALLOC_DEVICE, __func__);
46 }
47 
48 EXTERN void *llvm_omp_target_alloc_host(size_t size, int device_num) {
49   return targetAllocExplicit(size, device_num, TARGET_ALLOC_HOST, __func__);
50 }
51 
52 EXTERN void *llvm_omp_target_alloc_shared(size_t size, int device_num) {
53   return targetAllocExplicit(size, device_num, TARGET_ALLOC_SHARED, __func__);
54 }
55 
56 EXTERN void *llvm_omp_get_dynamic_shared() { return nullptr; }
57 
58 EXTERN void omp_target_free(void *device_ptr, int device_num) {
59   TIMESCOPE();
60   DP("Call to omp_target_free for device %d and address " DPxMOD "\n",
61      device_num, DPxPTR(device_ptr));
62 
63   if (!device_ptr) {
64     DP("Call to omp_target_free with NULL ptr\n");
65     return;
66   }
67 
68   if (device_num == omp_get_initial_device()) {
69     free(device_ptr);
70     DP("omp_target_free deallocated host ptr\n");
71     return;
72   }
73 
74   if (!device_is_ready(device_num)) {
75     DP("omp_target_free returns, nothing to do\n");
76     return;
77   }
78 
79   PM->Devices[device_num]->deleteData(device_ptr);
80   DP("omp_target_free deallocated device ptr\n");
81 }
82 
83 EXTERN int omp_target_is_present(const void *ptr, int device_num) {
84   TIMESCOPE();
85   DP("Call to omp_target_is_present for device %d and address " DPxMOD "\n",
86      device_num, DPxPTR(ptr));
87 
88   if (!ptr) {
89     DP("Call to omp_target_is_present with NULL ptr, returning false\n");
90     return false;
91   }
92 
93   if (device_num == omp_get_initial_device()) {
94     DP("Call to omp_target_is_present on host, returning true\n");
95     return true;
96   }
97 
98   PM->RTLsMtx.lock();
99   size_t DevicesSize = PM->Devices.size();
100   PM->RTLsMtx.unlock();
101   if (DevicesSize <= (size_t)device_num) {
102     DP("Call to omp_target_is_present with invalid device ID, returning "
103        "false\n");
104     return false;
105   }
106 
107   DeviceTy &Device = *PM->Devices[device_num];
108   bool IsLast; // not used
109   bool IsHostPtr;
110   TargetPointerResultTy TPR =
111       Device.getTgtPtrBegin(const_cast<void *>(ptr), 0, IsLast,
112                             /*UpdateRefCount=*/false,
113                             /*UseHoldRefCount=*/false, IsHostPtr);
114   int rc = (TPR.TargetPointer != NULL);
115   // Under unified memory the host pointer can be returned by the
116   // getTgtPtrBegin() function which means that there is no device
117   // corresponding point for ptr. This function should return false
118   // in that situation.
119   if (PM->RTLs.RequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY)
120     rc = !IsHostPtr;
121   DP("Call to omp_target_is_present returns %d\n", rc);
122   return rc;
123 }
124 
125 EXTERN int omp_target_memcpy(void *dst, const void *src, size_t length,
126                              size_t dst_offset, size_t src_offset,
127                              int dst_device, int src_device) {
128   TIMESCOPE();
129   DP("Call to omp_target_memcpy, dst device %d, src device %d, "
130      "dst addr " DPxMOD ", src addr " DPxMOD ", dst offset %zu, "
131      "src offset %zu, length %zu\n",
132      dst_device, src_device, DPxPTR(dst), DPxPTR(src), dst_offset, src_offset,
133      length);
134 
135   if (!dst || !src || length <= 0) {
136     if (length == 0) {
137       DP("Call to omp_target_memcpy with zero length, nothing to do\n");
138       return OFFLOAD_SUCCESS;
139     }
140 
141     REPORT("Call to omp_target_memcpy with invalid arguments\n");
142     return OFFLOAD_FAIL;
143   }
144 
145   if (src_device != omp_get_initial_device() && !device_is_ready(src_device)) {
146     REPORT("omp_target_memcpy returns OFFLOAD_FAIL\n");
147     return OFFLOAD_FAIL;
148   }
149 
150   if (dst_device != omp_get_initial_device() && !device_is_ready(dst_device)) {
151     REPORT("omp_target_memcpy returns OFFLOAD_FAIL\n");
152     return OFFLOAD_FAIL;
153   }
154 
155   int rc = OFFLOAD_SUCCESS;
156   void *srcAddr = (char *)const_cast<void *>(src) + src_offset;
157   void *dstAddr = (char *)dst + dst_offset;
158 
159   if (src_device == omp_get_initial_device() &&
160       dst_device == omp_get_initial_device()) {
161     DP("copy from host to host\n");
162     const void *p = memcpy(dstAddr, srcAddr, length);
163     if (p == NULL)
164       rc = OFFLOAD_FAIL;
165   } else if (src_device == omp_get_initial_device()) {
166     DP("copy from host to device\n");
167     DeviceTy &DstDev = *PM->Devices[dst_device];
168     AsyncInfoTy AsyncInfo(DstDev);
169     rc = DstDev.submitData(dstAddr, srcAddr, length, AsyncInfo);
170   } else if (dst_device == omp_get_initial_device()) {
171     DP("copy from device to host\n");
172     DeviceTy &SrcDev = *PM->Devices[src_device];
173     AsyncInfoTy AsyncInfo(SrcDev);
174     rc = SrcDev.retrieveData(dstAddr, srcAddr, length, AsyncInfo);
175   } else {
176     DP("copy from device to device\n");
177     DeviceTy &SrcDev = *PM->Devices[src_device];
178     DeviceTy &DstDev = *PM->Devices[dst_device];
179     // First try to use D2D memcpy which is more efficient. If fails, fall back
180     // to unefficient way.
181     if (SrcDev.isDataExchangable(DstDev)) {
182       AsyncInfoTy AsyncInfo(SrcDev);
183       rc = SrcDev.dataExchange(srcAddr, DstDev, dstAddr, length, AsyncInfo);
184       if (rc == OFFLOAD_SUCCESS)
185         return OFFLOAD_SUCCESS;
186     }
187 
188     void *buffer = malloc(length);
189     {
190       AsyncInfoTy AsyncInfo(SrcDev);
191       rc = SrcDev.retrieveData(buffer, srcAddr, length, AsyncInfo);
192     }
193     if (rc == OFFLOAD_SUCCESS) {
194       AsyncInfoTy AsyncInfo(SrcDev);
195       rc = DstDev.submitData(dstAddr, buffer, length, AsyncInfo);
196     }
197     free(buffer);
198   }
199 
200   DP("omp_target_memcpy returns %d\n", rc);
201   return rc;
202 }
203 
204 EXTERN int omp_target_memcpy_rect(
205     void *dst, const void *src, size_t element_size, int num_dims,
206     const size_t *volume, const size_t *dst_offsets, const size_t *src_offsets,
207     const size_t *dst_dimensions, const size_t *src_dimensions, int dst_device,
208     int src_device) {
209   TIMESCOPE();
210   DP("Call to omp_target_memcpy_rect, dst device %d, src device %d, "
211      "dst addr " DPxMOD ", src addr " DPxMOD ", dst offsets " DPxMOD ", "
212      "src offsets " DPxMOD ", dst dims " DPxMOD ", src dims " DPxMOD ", "
213      "volume " DPxMOD ", element size %zu, num_dims %d\n",
214      dst_device, src_device, DPxPTR(dst), DPxPTR(src), DPxPTR(dst_offsets),
215      DPxPTR(src_offsets), DPxPTR(dst_dimensions), DPxPTR(src_dimensions),
216      DPxPTR(volume), element_size, num_dims);
217 
218   if (!(dst || src)) {
219     DP("Call to omp_target_memcpy_rect returns max supported dimensions %d\n",
220        INT_MAX);
221     return INT_MAX;
222   }
223 
224   if (!dst || !src || element_size < 1 || num_dims < 1 || !volume ||
225       !dst_offsets || !src_offsets || !dst_dimensions || !src_dimensions) {
226     REPORT("Call to omp_target_memcpy_rect with invalid arguments\n");
227     return OFFLOAD_FAIL;
228   }
229 
230   int rc;
231   if (num_dims == 1) {
232     rc = omp_target_memcpy(
233         dst, src, element_size * volume[0], element_size * dst_offsets[0],
234         element_size * src_offsets[0], dst_device, src_device);
235   } else {
236     size_t dst_slice_size = element_size;
237     size_t src_slice_size = element_size;
238     for (int i = 1; i < num_dims; ++i) {
239       dst_slice_size *= dst_dimensions[i];
240       src_slice_size *= src_dimensions[i];
241     }
242 
243     size_t dst_off = dst_offsets[0] * dst_slice_size;
244     size_t src_off = src_offsets[0] * src_slice_size;
245     for (size_t i = 0; i < volume[0]; ++i) {
246       rc = omp_target_memcpy_rect(
247           (char *)dst + dst_off + dst_slice_size * i,
248           (char *)const_cast<void *>(src) + src_off + src_slice_size * i,
249           element_size, num_dims - 1, volume + 1, dst_offsets + 1,
250           src_offsets + 1, dst_dimensions + 1, src_dimensions + 1, dst_device,
251           src_device);
252 
253       if (rc) {
254         DP("Recursive call to omp_target_memcpy_rect returns unsuccessfully\n");
255         return rc;
256       }
257     }
258   }
259 
260   DP("omp_target_memcpy_rect returns %d\n", rc);
261   return rc;
262 }
263 
264 EXTERN int omp_target_associate_ptr(const void *host_ptr,
265                                     const void *device_ptr, size_t size,
266                                     size_t device_offset, int device_num) {
267   TIMESCOPE();
268   DP("Call to omp_target_associate_ptr with host_ptr " DPxMOD ", "
269      "device_ptr " DPxMOD ", size %zu, device_offset %zu, device_num %d\n",
270      DPxPTR(host_ptr), DPxPTR(device_ptr), size, device_offset, device_num);
271 
272   if (!host_ptr || !device_ptr || size <= 0) {
273     REPORT("Call to omp_target_associate_ptr with invalid arguments\n");
274     return OFFLOAD_FAIL;
275   }
276 
277   if (device_num == omp_get_initial_device()) {
278     REPORT("omp_target_associate_ptr: no association possible on the host\n");
279     return OFFLOAD_FAIL;
280   }
281 
282   if (!device_is_ready(device_num)) {
283     REPORT("omp_target_associate_ptr returns OFFLOAD_FAIL\n");
284     return OFFLOAD_FAIL;
285   }
286 
287   DeviceTy &Device = *PM->Devices[device_num];
288   void *device_addr = (void *)((uint64_t)device_ptr + (uint64_t)device_offset);
289   int rc = Device.associatePtr(const_cast<void *>(host_ptr),
290                                const_cast<void *>(device_addr), size);
291   DP("omp_target_associate_ptr returns %d\n", rc);
292   return rc;
293 }
294 
295 EXTERN int omp_target_disassociate_ptr(const void *host_ptr, int device_num) {
296   TIMESCOPE();
297   DP("Call to omp_target_disassociate_ptr with host_ptr " DPxMOD ", "
298      "device_num %d\n",
299      DPxPTR(host_ptr), device_num);
300 
301   if (!host_ptr) {
302     REPORT("Call to omp_target_associate_ptr with invalid host_ptr\n");
303     return OFFLOAD_FAIL;
304   }
305 
306   if (device_num == omp_get_initial_device()) {
307     REPORT(
308         "omp_target_disassociate_ptr: no association possible on the host\n");
309     return OFFLOAD_FAIL;
310   }
311 
312   if (!device_is_ready(device_num)) {
313     REPORT("omp_target_disassociate_ptr returns OFFLOAD_FAIL\n");
314     return OFFLOAD_FAIL;
315   }
316 
317   DeviceTy &Device = *PM->Devices[device_num];
318   int rc = Device.disassociatePtr(const_cast<void *>(host_ptr));
319   DP("omp_target_disassociate_ptr returns %d\n", rc);
320   return rc;
321 }
322