• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*===---- cuda_builtin_vars.h - CUDA built-in variables ---------------------===
2  *
3  * Permission is hereby granted, free of charge, to any person obtaining a copy
4  * of this software and associated documentation files (the "Software"), to deal
5  * in the Software without restriction, including without limitation the rights
6  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
7  * copies of the Software, and to permit persons to whom the Software is
8  * furnished to do so, subject to the following conditions:
9  *
10  * The above copyright notice and this permission notice shall be included in
11  * all copies or substantial portions of the Software.
12  *
13  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
18  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
19  * THE SOFTWARE.
20  *
21  *===-----------------------------------------------------------------------===
22  */
23 
24 #ifndef __CUDA_BUILTIN_VARS_H
25 #define __CUDA_BUILTIN_VARS_H
26 
27 // Forward declares from vector_types.h.
28 struct uint3;
29 struct dim3;
30 
31 // The file implements built-in CUDA variables using __declspec(property).
32 // https://msdn.microsoft.com/en-us/library/yhfk0thd.aspx
33 // All read accesses of built-in variable fields get converted into calls to a
34 // getter function which in turn calls the appropriate builtin to fetch the
35 // value.
36 //
37 // Example:
38 //    int x = threadIdx.x;
39 // IR output:
40 //  %0 = call i32 @llvm.nvvm.read.ptx.sreg.tid.x() #3
41 // PTX output:
42 //  mov.u32     %r2, %tid.x;
43 
44 #define __CUDA_DEVICE_BUILTIN(FIELD, INTRINSIC)                                \
45   __declspec(property(get = __fetch_builtin_##FIELD)) unsigned int FIELD;      \
46   static inline __attribute__((always_inline))                                 \
47       __attribute__((device)) unsigned int __fetch_builtin_##FIELD(void) {     \
48     return INTRINSIC;                                                          \
49   }
50 
51 #if __cplusplus >= 201103L
52 #define __DELETE =delete
53 #else
54 #define __DELETE
55 #endif
56 
57 // Make sure nobody can create instances of the special varible types.  nvcc
58 // also disallows taking address of special variables, so we disable address-of
59 // operator as well.
60 #define __CUDA_DISALLOW_BUILTINVAR_ACCESS(TypeName)                            \
61   __attribute__((device)) TypeName() __DELETE;                                 \
62   __attribute__((device)) TypeName(const TypeName &) __DELETE;                 \
63   __attribute__((device)) void operator=(const TypeName &) const __DELETE;     \
64   __attribute__((device)) TypeName *operator&() const __DELETE
65 
66 struct __cuda_builtin_threadIdx_t {
67   __CUDA_DEVICE_BUILTIN(x,__nvvm_read_ptx_sreg_tid_x());
68   __CUDA_DEVICE_BUILTIN(y,__nvvm_read_ptx_sreg_tid_y());
69   __CUDA_DEVICE_BUILTIN(z,__nvvm_read_ptx_sreg_tid_z());
70   // threadIdx should be convertible to uint3 (in fact in nvcc, it *is* a
71   // uint3).  This function is defined after we pull in vector_types.h.
72   __attribute__((device)) operator uint3() const;
73 private:
74   __CUDA_DISALLOW_BUILTINVAR_ACCESS(__cuda_builtin_threadIdx_t);
75 };
76 
77 struct __cuda_builtin_blockIdx_t {
78   __CUDA_DEVICE_BUILTIN(x,__nvvm_read_ptx_sreg_ctaid_x());
79   __CUDA_DEVICE_BUILTIN(y,__nvvm_read_ptx_sreg_ctaid_y());
80   __CUDA_DEVICE_BUILTIN(z,__nvvm_read_ptx_sreg_ctaid_z());
81   // blockIdx should be convertible to uint3 (in fact in nvcc, it *is* a
82   // uint3).  This function is defined after we pull in vector_types.h.
83   __attribute__((device)) operator uint3() const;
84 private:
85   __CUDA_DISALLOW_BUILTINVAR_ACCESS(__cuda_builtin_blockIdx_t);
86 };
87 
88 struct __cuda_builtin_blockDim_t {
89   __CUDA_DEVICE_BUILTIN(x,__nvvm_read_ptx_sreg_ntid_x());
90   __CUDA_DEVICE_BUILTIN(y,__nvvm_read_ptx_sreg_ntid_y());
91   __CUDA_DEVICE_BUILTIN(z,__nvvm_read_ptx_sreg_ntid_z());
92   // blockDim should be convertible to dim3 (in fact in nvcc, it *is* a
93   // dim3).  This function is defined after we pull in vector_types.h.
94   __attribute__((device)) operator dim3() const;
95 private:
96   __CUDA_DISALLOW_BUILTINVAR_ACCESS(__cuda_builtin_blockDim_t);
97 };
98 
99 struct __cuda_builtin_gridDim_t {
100   __CUDA_DEVICE_BUILTIN(x,__nvvm_read_ptx_sreg_nctaid_x());
101   __CUDA_DEVICE_BUILTIN(y,__nvvm_read_ptx_sreg_nctaid_y());
102   __CUDA_DEVICE_BUILTIN(z,__nvvm_read_ptx_sreg_nctaid_z());
103   // gridDim should be convertible to dim3 (in fact in nvcc, it *is* a
104   // dim3).  This function is defined after we pull in vector_types.h.
105   __attribute__((device)) operator dim3() const;
106 private:
107   __CUDA_DISALLOW_BUILTINVAR_ACCESS(__cuda_builtin_gridDim_t);
108 };
109 
110 #define __CUDA_BUILTIN_VAR                                                     \
111   extern const __attribute__((device)) __attribute__((weak))
112 __CUDA_BUILTIN_VAR __cuda_builtin_threadIdx_t threadIdx;
113 __CUDA_BUILTIN_VAR __cuda_builtin_blockIdx_t blockIdx;
114 __CUDA_BUILTIN_VAR __cuda_builtin_blockDim_t blockDim;
115 __CUDA_BUILTIN_VAR __cuda_builtin_gridDim_t gridDim;
116 
117 // warpSize should translate to read of %WARP_SZ but there's currently no
118 // builtin to do so. According to PTX v4.2 docs 'to date, all target
119 // architectures have a WARP_SZ value of 32'.
120 __attribute__((device)) const int warpSize = 32;
121 
122 #undef __CUDA_DEVICE_BUILTIN
123 #undef __CUDA_BUILTIN_VAR
124 #undef __CUDA_DISALLOW_BUILTINVAR_ACCESS
125 
126 #endif /* __CUDA_BUILTIN_VARS_H */
127