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   void *TgtPtr = Device.getTgtPtrBegin(const_cast<void *>(ptr), 0, IsLast,
111                                        /*UpdateRefCount=*/false,
112                                        /*UseHoldRefCount=*/false, IsHostPtr);
113   int rc = (TgtPtr != NULL);
114   // Under unified memory the host pointer can be returned by the
115   // getTgtPtrBegin() function which means that there is no device
116   // corresponding point for ptr. This function should return false
117   // in that situation.
118   if (PM->RTLs.RequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY)
119     rc = !IsHostPtr;
120   DP("Call to omp_target_is_present returns %d\n", rc);
121   return rc;
122 }
123 
124 EXTERN int omp_target_memcpy(void *dst, const void *src, size_t length,
125                              size_t dst_offset, size_t src_offset,
126                              int dst_device, int src_device) {
127   TIMESCOPE();
128   DP("Call to omp_target_memcpy, dst device %d, src device %d, "
129      "dst addr " DPxMOD ", src addr " DPxMOD ", dst offset %zu, "
130      "src offset %zu, length %zu\n",
131      dst_device, src_device, DPxPTR(dst), DPxPTR(src), dst_offset, src_offset,
132      length);
133 
134   if (!dst || !src || length <= 0) {
135     if (length == 0) {
136       DP("Call to omp_target_memcpy with zero length, nothing to do\n");
137       return OFFLOAD_SUCCESS;
138     }
139 
140     REPORT("Call to omp_target_memcpy with invalid arguments\n");
141     return OFFLOAD_FAIL;
142   }
143 
144   if (src_device != omp_get_initial_device() && !device_is_ready(src_device)) {
145     REPORT("omp_target_memcpy returns OFFLOAD_FAIL\n");
146     return OFFLOAD_FAIL;
147   }
148 
149   if (dst_device != omp_get_initial_device() && !device_is_ready(dst_device)) {
150     REPORT("omp_target_memcpy returns OFFLOAD_FAIL\n");
151     return OFFLOAD_FAIL;
152   }
153 
154   int rc = OFFLOAD_SUCCESS;
155   void *srcAddr = (char *)const_cast<void *>(src) + src_offset;
156   void *dstAddr = (char *)dst + dst_offset;
157 
158   if (src_device == omp_get_initial_device() &&
159       dst_device == omp_get_initial_device()) {
160     DP("copy from host to host\n");
161     const void *p = memcpy(dstAddr, srcAddr, length);
162     if (p == NULL)
163       rc = OFFLOAD_FAIL;
164   } else if (src_device == omp_get_initial_device()) {
165     DP("copy from host to device\n");
166     DeviceTy &DstDev = *PM->Devices[dst_device];
167     AsyncInfoTy AsyncInfo(DstDev);
168     rc = DstDev.submitData(dstAddr, srcAddr, length, AsyncInfo);
169   } else if (dst_device == omp_get_initial_device()) {
170     DP("copy from device to host\n");
171     DeviceTy &SrcDev = *PM->Devices[src_device];
172     AsyncInfoTy AsyncInfo(SrcDev);
173     rc = SrcDev.retrieveData(dstAddr, srcAddr, length, AsyncInfo);
174   } else {
175     DP("copy from device to device\n");
176     DeviceTy &SrcDev = *PM->Devices[src_device];
177     DeviceTy &DstDev = *PM->Devices[dst_device];
178     // First try to use D2D memcpy which is more efficient. If fails, fall back
179     // to unefficient way.
180     if (SrcDev.isDataExchangable(DstDev)) {
181       AsyncInfoTy AsyncInfo(SrcDev);
182       rc = SrcDev.dataExchange(srcAddr, DstDev, dstAddr, length, AsyncInfo);
183       if (rc == OFFLOAD_SUCCESS)
184         return OFFLOAD_SUCCESS;
185     }
186 
187     void *buffer = malloc(length);
188     {
189       AsyncInfoTy AsyncInfo(SrcDev);
190       rc = SrcDev.retrieveData(buffer, srcAddr, length, AsyncInfo);
191     }
192     if (rc == OFFLOAD_SUCCESS) {
193       AsyncInfoTy AsyncInfo(SrcDev);
194       rc = DstDev.submitData(dstAddr, buffer, length, AsyncInfo);
195     }
196     free(buffer);
197   }
198 
199   DP("omp_target_memcpy returns %d\n", rc);
200   return rc;
201 }
202 
203 EXTERN int omp_target_memcpy_rect(
204     void *dst, const void *src, size_t element_size, int num_dims,
205     const size_t *volume, const size_t *dst_offsets, const size_t *src_offsets,
206     const size_t *dst_dimensions, const size_t *src_dimensions, int dst_device,
207     int src_device) {
208   TIMESCOPE();
209   DP("Call to omp_target_memcpy_rect, dst device %d, src device %d, "
210      "dst addr " DPxMOD ", src addr " DPxMOD ", dst offsets " DPxMOD ", "
211      "src offsets " DPxMOD ", dst dims " DPxMOD ", src dims " DPxMOD ", "
212      "volume " DPxMOD ", element size %zu, num_dims %d\n",
213      dst_device, src_device, DPxPTR(dst), DPxPTR(src), DPxPTR(dst_offsets),
214      DPxPTR(src_offsets), DPxPTR(dst_dimensions), DPxPTR(src_dimensions),
215      DPxPTR(volume), element_size, num_dims);
216 
217   if (!(dst || src)) {
218     DP("Call to omp_target_memcpy_rect returns max supported dimensions %d\n",
219        INT_MAX);
220     return INT_MAX;
221   }
222 
223   if (!dst || !src || element_size < 1 || num_dims < 1 || !volume ||
224       !dst_offsets || !src_offsets || !dst_dimensions || !src_dimensions) {
225     REPORT("Call to omp_target_memcpy_rect with invalid arguments\n");
226     return OFFLOAD_FAIL;
227   }
228 
229   int rc;
230   if (num_dims == 1) {
231     rc = omp_target_memcpy(
232         dst, src, element_size * volume[0], element_size * dst_offsets[0],
233         element_size * src_offsets[0], dst_device, src_device);
234   } else {
235     size_t dst_slice_size = element_size;
236     size_t src_slice_size = element_size;
237     for (int i = 1; i < num_dims; ++i) {
238       dst_slice_size *= dst_dimensions[i];
239       src_slice_size *= src_dimensions[i];
240     }
241 
242     size_t dst_off = dst_offsets[0] * dst_slice_size;
243     size_t src_off = src_offsets[0] * src_slice_size;
244     for (size_t i = 0; i < volume[0]; ++i) {
245       rc = omp_target_memcpy_rect(
246           (char *)dst + dst_off + dst_slice_size * i,
247           (char *)const_cast<void *>(src) + src_off + src_slice_size * i,
248           element_size, num_dims - 1, volume + 1, dst_offsets + 1,
249           src_offsets + 1, dst_dimensions + 1, src_dimensions + 1, dst_device,
250           src_device);
251 
252       if (rc) {
253         DP("Recursive call to omp_target_memcpy_rect returns unsuccessfully\n");
254         return rc;
255       }
256     }
257   }
258 
259   DP("omp_target_memcpy_rect returns %d\n", rc);
260   return rc;
261 }
262 
263 EXTERN int omp_target_associate_ptr(const void *host_ptr,
264                                     const void *device_ptr, size_t size,
265                                     size_t device_offset, int device_num) {
266   TIMESCOPE();
267   DP("Call to omp_target_associate_ptr with host_ptr " DPxMOD ", "
268      "device_ptr " DPxMOD ", size %zu, device_offset %zu, device_num %d\n",
269      DPxPTR(host_ptr), DPxPTR(device_ptr), size, device_offset, device_num);
270 
271   if (!host_ptr || !device_ptr || size <= 0) {
272     REPORT("Call to omp_target_associate_ptr with invalid arguments\n");
273     return OFFLOAD_FAIL;
274   }
275 
276   if (device_num == omp_get_initial_device()) {
277     REPORT("omp_target_associate_ptr: no association possible on the host\n");
278     return OFFLOAD_FAIL;
279   }
280 
281   if (!device_is_ready(device_num)) {
282     REPORT("omp_target_associate_ptr returns OFFLOAD_FAIL\n");
283     return OFFLOAD_FAIL;
284   }
285 
286   DeviceTy &Device = *PM->Devices[device_num];
287   void *device_addr = (void *)((uint64_t)device_ptr + (uint64_t)device_offset);
288   int rc = Device.associatePtr(const_cast<void *>(host_ptr),
289                                const_cast<void *>(device_addr), size);
290   DP("omp_target_associate_ptr returns %d\n", rc);
291   return rc;
292 }
293 
294 EXTERN int omp_target_disassociate_ptr(const void *host_ptr, int device_num) {
295   TIMESCOPE();
296   DP("Call to omp_target_disassociate_ptr with host_ptr " DPxMOD ", "
297      "device_num %d\n",
298      DPxPTR(host_ptr), device_num);
299 
300   if (!host_ptr) {
301     REPORT("Call to omp_target_associate_ptr with invalid host_ptr\n");
302     return OFFLOAD_FAIL;
303   }
304 
305   if (device_num == omp_get_initial_device()) {
306     REPORT(
307         "omp_target_disassociate_ptr: no association possible on the host\n");
308     return OFFLOAD_FAIL;
309   }
310 
311   if (!device_is_ready(device_num)) {
312     REPORT("omp_target_disassociate_ptr returns OFFLOAD_FAIL\n");
313     return OFFLOAD_FAIL;
314   }
315 
316   DeviceTy &Device = *PM->Devices[device_num];
317   int rc = Device.disassociatePtr(const_cast<void *>(host_ptr));
318   DP("omp_target_disassociate_ptr returns %d\n", rc);
319   return rc;
320 }
321