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_device_num(void) {
34   TIMESCOPE();
35   int HostDevice = omp_get_initial_device();
36 
37   DP("Call to omp_get_device_num returning %d\n", HostDevice);
38 
39   return HostDevice;
40 }
41 
42 EXTERN int omp_get_initial_device(void) {
43   TIMESCOPE();
44   int hostDevice = omp_get_num_devices();
45   DP("Call to omp_get_initial_device returning %d\n", hostDevice);
46   return hostDevice;
47 }
48 
49 EXTERN void *omp_target_alloc(size_t size, int device_num) {
50   return targetAllocExplicit(size, device_num, TARGET_ALLOC_DEFAULT, __func__);
51 }
52 
53 EXTERN void *llvm_omp_target_alloc_device(size_t size, int device_num) {
54   return targetAllocExplicit(size, device_num, TARGET_ALLOC_DEVICE, __func__);
55 }
56 
57 EXTERN void *llvm_omp_target_alloc_host(size_t size, int device_num) {
58   return targetAllocExplicit(size, device_num, TARGET_ALLOC_HOST, __func__);
59 }
60 
61 EXTERN void *llvm_omp_target_alloc_shared(size_t size, int device_num) {
62   return targetAllocExplicit(size, device_num, TARGET_ALLOC_SHARED, __func__);
63 }
64 
65 EXTERN void *llvm_omp_target_dynamic_shared_alloc() { return nullptr; }
66 EXTERN void *llvm_omp_get_dynamic_shared() { return nullptr; }
67 
68 EXTERN void omp_target_free(void *device_ptr, int device_num) {
69   TIMESCOPE();
70   DP("Call to omp_target_free for device %d and address " DPxMOD "\n",
71      device_num, DPxPTR(device_ptr));
72 
73   if (!device_ptr) {
74     DP("Call to omp_target_free with NULL ptr\n");
75     return;
76   }
77 
78   if (device_num == omp_get_initial_device()) {
79     free(device_ptr);
80     DP("omp_target_free deallocated host ptr\n");
81     return;
82   }
83 
84   if (!device_is_ready(device_num)) {
85     DP("omp_target_free returns, nothing to do\n");
86     return;
87   }
88 
89   PM->Devices[device_num]->deleteData(device_ptr);
90   DP("omp_target_free deallocated device ptr\n");
91 }
92 
93 EXTERN int omp_target_is_present(const void *ptr, int device_num) {
94   TIMESCOPE();
95   DP("Call to omp_target_is_present for device %d and address " DPxMOD "\n",
96      device_num, DPxPTR(ptr));
97 
98   if (!ptr) {
99     DP("Call to omp_target_is_present with NULL ptr, returning false\n");
100     return false;
101   }
102 
103   if (device_num == omp_get_initial_device()) {
104     DP("Call to omp_target_is_present on host, returning true\n");
105     return true;
106   }
107 
108   PM->RTLsMtx.lock();
109   size_t DevicesSize = PM->Devices.size();
110   PM->RTLsMtx.unlock();
111   if (DevicesSize <= (size_t)device_num) {
112     DP("Call to omp_target_is_present with invalid device ID, returning "
113        "false\n");
114     return false;
115   }
116 
117   DeviceTy &Device = *PM->Devices[device_num];
118   bool IsLast; // not used
119   bool IsHostPtr;
120   // omp_target_is_present tests whether a host pointer refers to storage that
121   // is mapped to a given device. However, due to the lack of the storage size,
122   // only check 1 byte. Cannot set size 0 which checks whether the pointer (zero
123   // lengh array) is mapped instead of the referred storage.
124   TargetPointerResultTy TPR =
125       Device.getTgtPtrBegin(const_cast<void *>(ptr), 1, IsLast,
126                             /*UpdateRefCount=*/false,
127                             /*UseHoldRefCount=*/false, IsHostPtr);
128   int rc = (TPR.TargetPointer != NULL);
129   // Under unified memory the host pointer can be returned by the
130   // getTgtPtrBegin() function which means that there is no device
131   // corresponding point for ptr. This function should return false
132   // in that situation.
133   if (PM->RTLs.RequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY)
134     rc = !IsHostPtr;
135   DP("Call to omp_target_is_present returns %d\n", rc);
136   return rc;
137 }
138 
139 EXTERN int omp_target_memcpy(void *dst, const void *src, size_t length,
140                              size_t dst_offset, size_t src_offset,
141                              int dst_device, int src_device) {
142   TIMESCOPE();
143   DP("Call to omp_target_memcpy, dst device %d, src device %d, "
144      "dst addr " DPxMOD ", src addr " DPxMOD ", dst offset %zu, "
145      "src offset %zu, length %zu\n",
146      dst_device, src_device, DPxPTR(dst), DPxPTR(src), dst_offset, src_offset,
147      length);
148 
149   if (!dst || !src || length <= 0) {
150     if (length == 0) {
151       DP("Call to omp_target_memcpy with zero length, nothing to do\n");
152       return OFFLOAD_SUCCESS;
153     }
154 
155     REPORT("Call to omp_target_memcpy with invalid arguments\n");
156     return OFFLOAD_FAIL;
157   }
158 
159   if (src_device != omp_get_initial_device() && !device_is_ready(src_device)) {
160     REPORT("omp_target_memcpy returns OFFLOAD_FAIL\n");
161     return OFFLOAD_FAIL;
162   }
163 
164   if (dst_device != omp_get_initial_device() && !device_is_ready(dst_device)) {
165     REPORT("omp_target_memcpy returns OFFLOAD_FAIL\n");
166     return OFFLOAD_FAIL;
167   }
168 
169   int rc = OFFLOAD_SUCCESS;
170   void *srcAddr = (char *)const_cast<void *>(src) + src_offset;
171   void *dstAddr = (char *)dst + dst_offset;
172 
173   if (src_device == omp_get_initial_device() &&
174       dst_device == omp_get_initial_device()) {
175     DP("copy from host to host\n");
176     const void *p = memcpy(dstAddr, srcAddr, length);
177     if (p == NULL)
178       rc = OFFLOAD_FAIL;
179   } else if (src_device == omp_get_initial_device()) {
180     DP("copy from host to device\n");
181     DeviceTy &DstDev = *PM->Devices[dst_device];
182     AsyncInfoTy AsyncInfo(DstDev);
183     rc = DstDev.submitData(dstAddr, srcAddr, length, AsyncInfo);
184   } else if (dst_device == omp_get_initial_device()) {
185     DP("copy from device to host\n");
186     DeviceTy &SrcDev = *PM->Devices[src_device];
187     AsyncInfoTy AsyncInfo(SrcDev);
188     rc = SrcDev.retrieveData(dstAddr, srcAddr, length, AsyncInfo);
189   } else {
190     DP("copy from device to device\n");
191     DeviceTy &SrcDev = *PM->Devices[src_device];
192     DeviceTy &DstDev = *PM->Devices[dst_device];
193     // First try to use D2D memcpy which is more efficient. If fails, fall back
194     // to unefficient way.
195     if (SrcDev.isDataExchangable(DstDev)) {
196       AsyncInfoTy AsyncInfo(SrcDev);
197       rc = SrcDev.dataExchange(srcAddr, DstDev, dstAddr, length, AsyncInfo);
198       if (rc == OFFLOAD_SUCCESS)
199         return OFFLOAD_SUCCESS;
200     }
201 
202     void *buffer = malloc(length);
203     {
204       AsyncInfoTy AsyncInfo(SrcDev);
205       rc = SrcDev.retrieveData(buffer, srcAddr, length, AsyncInfo);
206     }
207     if (rc == OFFLOAD_SUCCESS) {
208       AsyncInfoTy AsyncInfo(SrcDev);
209       rc = DstDev.submitData(dstAddr, buffer, length, AsyncInfo);
210     }
211     free(buffer);
212   }
213 
214   DP("omp_target_memcpy returns %d\n", rc);
215   return rc;
216 }
217 
218 EXTERN int omp_target_memcpy_rect(
219     void *dst, const void *src, size_t element_size, int num_dims,
220     const size_t *volume, const size_t *dst_offsets, const size_t *src_offsets,
221     const size_t *dst_dimensions, const size_t *src_dimensions, int dst_device,
222     int src_device) {
223   TIMESCOPE();
224   DP("Call to omp_target_memcpy_rect, dst device %d, src device %d, "
225      "dst addr " DPxMOD ", src addr " DPxMOD ", dst offsets " DPxMOD ", "
226      "src offsets " DPxMOD ", dst dims " DPxMOD ", src dims " DPxMOD ", "
227      "volume " DPxMOD ", element size %zu, num_dims %d\n",
228      dst_device, src_device, DPxPTR(dst), DPxPTR(src), DPxPTR(dst_offsets),
229      DPxPTR(src_offsets), DPxPTR(dst_dimensions), DPxPTR(src_dimensions),
230      DPxPTR(volume), element_size, num_dims);
231 
232   if (!(dst || src)) {
233     DP("Call to omp_target_memcpy_rect returns max supported dimensions %d\n",
234        INT_MAX);
235     return INT_MAX;
236   }
237 
238   if (!dst || !src || element_size < 1 || num_dims < 1 || !volume ||
239       !dst_offsets || !src_offsets || !dst_dimensions || !src_dimensions) {
240     REPORT("Call to omp_target_memcpy_rect with invalid arguments\n");
241     return OFFLOAD_FAIL;
242   }
243 
244   int rc;
245   if (num_dims == 1) {
246     rc = omp_target_memcpy(
247         dst, src, element_size * volume[0], element_size * dst_offsets[0],
248         element_size * src_offsets[0], dst_device, src_device);
249   } else {
250     size_t dst_slice_size = element_size;
251     size_t src_slice_size = element_size;
252     for (int i = 1; i < num_dims; ++i) {
253       dst_slice_size *= dst_dimensions[i];
254       src_slice_size *= src_dimensions[i];
255     }
256 
257     size_t dst_off = dst_offsets[0] * dst_slice_size;
258     size_t src_off = src_offsets[0] * src_slice_size;
259     for (size_t i = 0; i < volume[0]; ++i) {
260       rc = omp_target_memcpy_rect(
261           (char *)dst + dst_off + dst_slice_size * i,
262           (char *)const_cast<void *>(src) + src_off + src_slice_size * i,
263           element_size, num_dims - 1, volume + 1, dst_offsets + 1,
264           src_offsets + 1, dst_dimensions + 1, src_dimensions + 1, dst_device,
265           src_device);
266 
267       if (rc) {
268         DP("Recursive call to omp_target_memcpy_rect returns unsuccessfully\n");
269         return rc;
270       }
271     }
272   }
273 
274   DP("omp_target_memcpy_rect returns %d\n", rc);
275   return rc;
276 }
277 
278 EXTERN int omp_target_associate_ptr(const void *host_ptr,
279                                     const void *device_ptr, size_t size,
280                                     size_t device_offset, int device_num) {
281   TIMESCOPE();
282   DP("Call to omp_target_associate_ptr with host_ptr " DPxMOD ", "
283      "device_ptr " DPxMOD ", size %zu, device_offset %zu, device_num %d\n",
284      DPxPTR(host_ptr), DPxPTR(device_ptr), size, device_offset, device_num);
285 
286   if (!host_ptr || !device_ptr || size <= 0) {
287     REPORT("Call to omp_target_associate_ptr with invalid arguments\n");
288     return OFFLOAD_FAIL;
289   }
290 
291   if (device_num == omp_get_initial_device()) {
292     REPORT("omp_target_associate_ptr: no association possible on the host\n");
293     return OFFLOAD_FAIL;
294   }
295 
296   if (!device_is_ready(device_num)) {
297     REPORT("omp_target_associate_ptr returns OFFLOAD_FAIL\n");
298     return OFFLOAD_FAIL;
299   }
300 
301   DeviceTy &Device = *PM->Devices[device_num];
302   void *device_addr = (void *)((uint64_t)device_ptr + (uint64_t)device_offset);
303   int rc = Device.associatePtr(const_cast<void *>(host_ptr),
304                                const_cast<void *>(device_addr), size);
305   DP("omp_target_associate_ptr returns %d\n", rc);
306   return rc;
307 }
308 
309 EXTERN int omp_target_disassociate_ptr(const void *host_ptr, int device_num) {
310   TIMESCOPE();
311   DP("Call to omp_target_disassociate_ptr with host_ptr " DPxMOD ", "
312      "device_num %d\n",
313      DPxPTR(host_ptr), device_num);
314 
315   if (!host_ptr) {
316     REPORT("Call to omp_target_associate_ptr with invalid host_ptr\n");
317     return OFFLOAD_FAIL;
318   }
319 
320   if (device_num == omp_get_initial_device()) {
321     REPORT(
322         "omp_target_disassociate_ptr: no association possible on the host\n");
323     return OFFLOAD_FAIL;
324   }
325 
326   if (!device_is_ready(device_num)) {
327     REPORT("omp_target_disassociate_ptr returns OFFLOAD_FAIL\n");
328     return OFFLOAD_FAIL;
329   }
330 
331   DeviceTy &Device = *PM->Devices[device_num];
332   int rc = Device.disassociatePtr(const_cast<void *>(host_ptr));
333   DP("omp_target_disassociate_ptr returns %d\n", rc);
334   return rc;
335 }
336