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_target_dynamic_shared_alloc() { return nullptr; }
57 EXTERN void *llvm_omp_get_dynamic_shared() { return nullptr; }
58 
59 EXTERN void omp_target_free(void *device_ptr, int device_num) {
60   TIMESCOPE();
61   DP("Call to omp_target_free for device %d and address " DPxMOD "\n",
62      device_num, DPxPTR(device_ptr));
63 
64   if (!device_ptr) {
65     DP("Call to omp_target_free with NULL ptr\n");
66     return;
67   }
68 
69   if (device_num == omp_get_initial_device()) {
70     free(device_ptr);
71     DP("omp_target_free deallocated host ptr\n");
72     return;
73   }
74 
75   if (!device_is_ready(device_num)) {
76     DP("omp_target_free returns, nothing to do\n");
77     return;
78   }
79 
80   PM->Devices[device_num]->deleteData(device_ptr);
81   DP("omp_target_free deallocated device ptr\n");
82 }
83 
84 EXTERN int omp_target_is_present(const void *ptr, int device_num) {
85   TIMESCOPE();
86   DP("Call to omp_target_is_present for device %d and address " DPxMOD "\n",
87      device_num, DPxPTR(ptr));
88 
89   if (!ptr) {
90     DP("Call to omp_target_is_present with NULL ptr, returning false\n");
91     return false;
92   }
93 
94   if (device_num == omp_get_initial_device()) {
95     DP("Call to omp_target_is_present on host, returning true\n");
96     return true;
97   }
98 
99   PM->RTLsMtx.lock();
100   size_t DevicesSize = PM->Devices.size();
101   PM->RTLsMtx.unlock();
102   if (DevicesSize <= (size_t)device_num) {
103     DP("Call to omp_target_is_present with invalid device ID, returning "
104        "false\n");
105     return false;
106   }
107 
108   DeviceTy &Device = *PM->Devices[device_num];
109   bool IsLast; // not used
110   bool IsHostPtr;
111   TargetPointerResultTy TPR =
112       Device.getTgtPtrBegin(const_cast<void *>(ptr), 0, IsLast,
113                             /*UpdateRefCount=*/false,
114                             /*UseHoldRefCount=*/false, IsHostPtr);
115   int rc = (TPR.TargetPointer != NULL);
116   // Under unified memory the host pointer can be returned by the
117   // getTgtPtrBegin() function which means that there is no device
118   // corresponding point for ptr. This function should return false
119   // in that situation.
120   if (PM->RTLs.RequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY)
121     rc = !IsHostPtr;
122   DP("Call to omp_target_is_present returns %d\n", rc);
123   return rc;
124 }
125 
126 EXTERN int omp_target_memcpy(void *dst, const void *src, size_t length,
127                              size_t dst_offset, size_t src_offset,
128                              int dst_device, int src_device) {
129   TIMESCOPE();
130   DP("Call to omp_target_memcpy, dst device %d, src device %d, "
131      "dst addr " DPxMOD ", src addr " DPxMOD ", dst offset %zu, "
132      "src offset %zu, length %zu\n",
133      dst_device, src_device, DPxPTR(dst), DPxPTR(src), dst_offset, src_offset,
134      length);
135 
136   if (!dst || !src || length <= 0) {
137     if (length == 0) {
138       DP("Call to omp_target_memcpy with zero length, nothing to do\n");
139       return OFFLOAD_SUCCESS;
140     }
141 
142     REPORT("Call to omp_target_memcpy with invalid arguments\n");
143     return OFFLOAD_FAIL;
144   }
145 
146   if (src_device != omp_get_initial_device() && !device_is_ready(src_device)) {
147     REPORT("omp_target_memcpy returns OFFLOAD_FAIL\n");
148     return OFFLOAD_FAIL;
149   }
150 
151   if (dst_device != omp_get_initial_device() && !device_is_ready(dst_device)) {
152     REPORT("omp_target_memcpy returns OFFLOAD_FAIL\n");
153     return OFFLOAD_FAIL;
154   }
155 
156   int rc = OFFLOAD_SUCCESS;
157   void *srcAddr = (char *)const_cast<void *>(src) + src_offset;
158   void *dstAddr = (char *)dst + dst_offset;
159 
160   if (src_device == omp_get_initial_device() &&
161       dst_device == omp_get_initial_device()) {
162     DP("copy from host to host\n");
163     const void *p = memcpy(dstAddr, srcAddr, length);
164     if (p == NULL)
165       rc = OFFLOAD_FAIL;
166   } else if (src_device == omp_get_initial_device()) {
167     DP("copy from host to device\n");
168     DeviceTy &DstDev = *PM->Devices[dst_device];
169     AsyncInfoTy AsyncInfo(DstDev);
170     rc = DstDev.submitData(dstAddr, srcAddr, length, AsyncInfo);
171   } else if (dst_device == omp_get_initial_device()) {
172     DP("copy from device to host\n");
173     DeviceTy &SrcDev = *PM->Devices[src_device];
174     AsyncInfoTy AsyncInfo(SrcDev);
175     rc = SrcDev.retrieveData(dstAddr, srcAddr, length, AsyncInfo);
176   } else {
177     DP("copy from device to device\n");
178     DeviceTy &SrcDev = *PM->Devices[src_device];
179     DeviceTy &DstDev = *PM->Devices[dst_device];
180     // First try to use D2D memcpy which is more efficient. If fails, fall back
181     // to unefficient way.
182     if (SrcDev.isDataExchangable(DstDev)) {
183       AsyncInfoTy AsyncInfo(SrcDev);
184       rc = SrcDev.dataExchange(srcAddr, DstDev, dstAddr, length, AsyncInfo);
185       if (rc == OFFLOAD_SUCCESS)
186         return OFFLOAD_SUCCESS;
187     }
188 
189     void *buffer = malloc(length);
190     {
191       AsyncInfoTy AsyncInfo(SrcDev);
192       rc = SrcDev.retrieveData(buffer, srcAddr, length, AsyncInfo);
193     }
194     if (rc == OFFLOAD_SUCCESS) {
195       AsyncInfoTy AsyncInfo(SrcDev);
196       rc = DstDev.submitData(dstAddr, buffer, length, AsyncInfo);
197     }
198     free(buffer);
199   }
200 
201   DP("omp_target_memcpy returns %d\n", rc);
202   return rc;
203 }
204 
205 EXTERN int omp_target_memcpy_rect(
206     void *dst, const void *src, size_t element_size, int num_dims,
207     const size_t *volume, const size_t *dst_offsets, const size_t *src_offsets,
208     const size_t *dst_dimensions, const size_t *src_dimensions, int dst_device,
209     int src_device) {
210   TIMESCOPE();
211   DP("Call to omp_target_memcpy_rect, dst device %d, src device %d, "
212      "dst addr " DPxMOD ", src addr " DPxMOD ", dst offsets " DPxMOD ", "
213      "src offsets " DPxMOD ", dst dims " DPxMOD ", src dims " DPxMOD ", "
214      "volume " DPxMOD ", element size %zu, num_dims %d\n",
215      dst_device, src_device, DPxPTR(dst), DPxPTR(src), DPxPTR(dst_offsets),
216      DPxPTR(src_offsets), DPxPTR(dst_dimensions), DPxPTR(src_dimensions),
217      DPxPTR(volume), element_size, num_dims);
218 
219   if (!(dst || src)) {
220     DP("Call to omp_target_memcpy_rect returns max supported dimensions %d\n",
221        INT_MAX);
222     return INT_MAX;
223   }
224 
225   if (!dst || !src || element_size < 1 || num_dims < 1 || !volume ||
226       !dst_offsets || !src_offsets || !dst_dimensions || !src_dimensions) {
227     REPORT("Call to omp_target_memcpy_rect with invalid arguments\n");
228     return OFFLOAD_FAIL;
229   }
230 
231   int rc;
232   if (num_dims == 1) {
233     rc = omp_target_memcpy(
234         dst, src, element_size * volume[0], element_size * dst_offsets[0],
235         element_size * src_offsets[0], dst_device, src_device);
236   } else {
237     size_t dst_slice_size = element_size;
238     size_t src_slice_size = element_size;
239     for (int i = 1; i < num_dims; ++i) {
240       dst_slice_size *= dst_dimensions[i];
241       src_slice_size *= src_dimensions[i];
242     }
243 
244     size_t dst_off = dst_offsets[0] * dst_slice_size;
245     size_t src_off = src_offsets[0] * src_slice_size;
246     for (size_t i = 0; i < volume[0]; ++i) {
247       rc = omp_target_memcpy_rect(
248           (char *)dst + dst_off + dst_slice_size * i,
249           (char *)const_cast<void *>(src) + src_off + src_slice_size * i,
250           element_size, num_dims - 1, volume + 1, dst_offsets + 1,
251           src_offsets + 1, dst_dimensions + 1, src_dimensions + 1, dst_device,
252           src_device);
253 
254       if (rc) {
255         DP("Recursive call to omp_target_memcpy_rect returns unsuccessfully\n");
256         return rc;
257       }
258     }
259   }
260 
261   DP("omp_target_memcpy_rect returns %d\n", rc);
262   return rc;
263 }
264 
265 EXTERN int omp_target_associate_ptr(const void *host_ptr,
266                                     const void *device_ptr, size_t size,
267                                     size_t device_offset, int device_num) {
268   TIMESCOPE();
269   DP("Call to omp_target_associate_ptr with host_ptr " DPxMOD ", "
270      "device_ptr " DPxMOD ", size %zu, device_offset %zu, device_num %d\n",
271      DPxPTR(host_ptr), DPxPTR(device_ptr), size, device_offset, device_num);
272 
273   if (!host_ptr || !device_ptr || size <= 0) {
274     REPORT("Call to omp_target_associate_ptr with invalid arguments\n");
275     return OFFLOAD_FAIL;
276   }
277 
278   if (device_num == omp_get_initial_device()) {
279     REPORT("omp_target_associate_ptr: no association possible on the host\n");
280     return OFFLOAD_FAIL;
281   }
282 
283   if (!device_is_ready(device_num)) {
284     REPORT("omp_target_associate_ptr returns OFFLOAD_FAIL\n");
285     return OFFLOAD_FAIL;
286   }
287 
288   DeviceTy &Device = *PM->Devices[device_num];
289   void *device_addr = (void *)((uint64_t)device_ptr + (uint64_t)device_offset);
290   int rc = Device.associatePtr(const_cast<void *>(host_ptr),
291                                const_cast<void *>(device_addr), size);
292   DP("omp_target_associate_ptr returns %d\n", rc);
293   return rc;
294 }
295 
296 EXTERN int omp_target_disassociate_ptr(const void *host_ptr, int device_num) {
297   TIMESCOPE();
298   DP("Call to omp_target_disassociate_ptr with host_ptr " DPxMOD ", "
299      "device_num %d\n",
300      DPxPTR(host_ptr), device_num);
301 
302   if (!host_ptr) {
303     REPORT("Call to omp_target_associate_ptr with invalid host_ptr\n");
304     return OFFLOAD_FAIL;
305   }
306 
307   if (device_num == omp_get_initial_device()) {
308     REPORT(
309         "omp_target_disassociate_ptr: no association possible on the host\n");
310     return OFFLOAD_FAIL;
311   }
312 
313   if (!device_is_ready(device_num)) {
314     REPORT("omp_target_disassociate_ptr returns OFFLOAD_FAIL\n");
315     return OFFLOAD_FAIL;
316   }
317 
318   DeviceTy &Device = *PM->Devices[device_num];
319   int rc = Device.disassociatePtr(const_cast<void *>(host_ptr));
320   DP("omp_target_disassociate_ptr returns %d\n", rc);
321   return rc;
322 }
323