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