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