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[cuda] Added support for CUDA built-in variables.

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Added cuda_builtin_vars.h which implements built-in CUDA variables
using __declattr(property).

Fields of built-in variables (except for warpSize) are implemented
using __declattr(property) which replaces read/write of a member field
with a call to a getter/setter member function, in this case with
appropriate NVPTX builtin.

Added a test case to check diagnostics on attempt to construct or
improperly access a built-in variable.

Differential Revision: http://reviews.llvm.org/D9064

llvm-svn: 235448
This commit is contained in:
Artem Belevich 2015-04-21 22:14:13 +00:00
parent e3476572f3
commit 4e192df778
4 changed files with 196 additions and 0 deletions
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1
clang/lib/Headers/CMakeLists.txt
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@ -13,6 +13,7 @@ set(files
bmi2intrin.h
bmiintrin.h
cpuid.h
cuda_builtin_vars.h
emmintrin.h
f16cintrin.h
float.h

110
clang/lib/Headers/cuda_builtin_vars.h Normal file
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@ -0,0 +1,110 @@
/*===---- cuda_builtin_vars.h - CUDA built-in variables ---------------------===
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
*===-----------------------------------------------------------------------===
*/
#ifndef __CUDA_BUILTIN_VARS_H
#define __CUDA_BUILTIN_VARS_H
// The file implements built-in CUDA variables using __declspec(property).
// https://msdn.microsoft.com/en-us/library/yhfk0thd.aspx
// All read accesses of built-in variable fields get converted into calls to a
// getter function which in turn would call appropriate builtin to fetch the
// value.
//
// Example:
// int x = threadIdx.x;
// IR output:
// %0 = call i32 @llvm.ptx.read.tid.x() #3
// PTX output:
// mov.u32 %r2, %tid.x;
#define __CUDA_DEVICE_BUILTIN(FIELD, INTRINSIC) \
__declspec(property(get = __fetch_builtin_##FIELD)) unsigned int FIELD; \
static inline __attribute__((always_inline)) \
__attribute__((device)) unsigned int __fetch_builtin_##FIELD(void) { \
return INTRINSIC; \
}
#if __cplusplus >= 201103L
#define __DELETE =delete
#else
#define __DELETE
#endif
// Make sure nobody can create instances of the special varible types. nvcc
// also disallows taking address of special variables, so we disable address-of
// operator as well.
#define __CUDA_DISALLOW_BUILTINVAR_ACCESS(TypeName) \
__attribute__((device)) TypeName() __DELETE; \
__attribute__((device)) TypeName(const TypeName &) __DELETE; \
__attribute__((device)) void operator=(const TypeName &) const __DELETE; \
__attribute__((device)) TypeName *operator&() const __DELETE
struct __cuda_builtin_threadIdx_t {
__CUDA_DEVICE_BUILTIN(x,__builtin_ptx_read_tid_x());
__CUDA_DEVICE_BUILTIN(y,__builtin_ptx_read_tid_y());
__CUDA_DEVICE_BUILTIN(z,__builtin_ptx_read_tid_z());
private:
__CUDA_DISALLOW_BUILTINVAR_ACCESS(__cuda_builtin_threadIdx_t);
};
struct __cuda_builtin_blockIdx_t {
__CUDA_DEVICE_BUILTIN(x,__builtin_ptx_read_ctaid_x());
__CUDA_DEVICE_BUILTIN(y,__builtin_ptx_read_ctaid_y());
__CUDA_DEVICE_BUILTIN(z,__builtin_ptx_read_ctaid_z());
private:
__CUDA_DISALLOW_BUILTINVAR_ACCESS(__cuda_builtin_blockIdx_t);
};
struct __cuda_builtin_blockDim_t {
__CUDA_DEVICE_BUILTIN(x,__builtin_ptx_read_ntid_x());
__CUDA_DEVICE_BUILTIN(y,__builtin_ptx_read_ntid_y());
__CUDA_DEVICE_BUILTIN(z,__builtin_ptx_read_ntid_z());
private:
__CUDA_DISALLOW_BUILTINVAR_ACCESS(__cuda_builtin_blockDim_t);
};
struct __cuda_builtin_gridDim_t {
__CUDA_DEVICE_BUILTIN(x,__builtin_ptx_read_nctaid_x());
__CUDA_DEVICE_BUILTIN(y,__builtin_ptx_read_nctaid_y());
__CUDA_DEVICE_BUILTIN(z,__builtin_ptx_read_nctaid_z());
private:
__CUDA_DISALLOW_BUILTINVAR_ACCESS(__cuda_builtin_gridDim_t);
};
#define __CUDA_BUILTIN_VAR \
extern const __attribute__((device)) __attribute__((weak))
__CUDA_BUILTIN_VAR __cuda_builtin_threadIdx_t threadIdx;
__CUDA_BUILTIN_VAR __cuda_builtin_blockIdx_t blockIdx;
__CUDA_BUILTIN_VAR __cuda_builtin_blockDim_t blockDim;
__CUDA_BUILTIN_VAR __cuda_builtin_gridDim_t gridDim;
// warpSize should translate to read of %WARP_SZ but there's currently no
// builtin to do so. According to PTX v4.2 docs 'to date, all target
// architectures have a WARP_SZ value of 32'.
__attribute__((device)) const int warpSize = 32;
#undef __CUDA_DEVICE_BUILTIN
#undef __CUDA_BUILTIN_VAR
#undef __CUDA_DISALLOW_BUILTINVAR_ACCESS
#endif /* __CUDA_BUILTIN_VARS_H */

28
clang/test/CodeGenCUDA/cuda-builtin-vars.cu Normal file
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// RUN: %clang_cc1 "-triple" "nvptx-nvidia-cuda" -emit-llvm -fcuda-is-device -o - %s | FileCheck %s
#include "cuda_builtin_vars.h"
// CHECK: define void @_Z6kernelPi(i32* %out)
__attribute__((global))
void kernel(int *out) {
int i = 0;
out[i++] = threadIdx.x; // CHECK: call i32 @llvm.ptx.read.tid.x()
out[i++] = threadIdx.y; // CHECK: call i32 @llvm.ptx.read.tid.y()
out[i++] = threadIdx.z; // CHECK: call i32 @llvm.ptx.read.tid.z()
out[i++] = blockIdx.x; // CHECK: call i32 @llvm.ptx.read.ctaid.x()
out[i++] = blockIdx.y; // CHECK: call i32 @llvm.ptx.read.ctaid.y()
out[i++] = blockIdx.z; // CHECK: call i32 @llvm.ptx.read.ctaid.z()
out[i++] = blockDim.x; // CHECK: call i32 @llvm.ptx.read.ntid.x()
out[i++] = blockDim.y; // CHECK: call i32 @llvm.ptx.read.ntid.y()
out[i++] = blockDim.z; // CHECK: call i32 @llvm.ptx.read.ntid.z()
out[i++] = gridDim.x; // CHECK: call i32 @llvm.ptx.read.nctaid.x()
out[i++] = gridDim.y; // CHECK: call i32 @llvm.ptx.read.nctaid.y()
out[i++] = gridDim.z; // CHECK: call i32 @llvm.ptx.read.nctaid.z()
out[i++] = warpSize; // CHECK: store i32 32,
// CHECK: ret void
}

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clang/test/SemaCUDA/cuda-builtin-vars.cu Normal file
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// RUN: %clang_cc1 "-triple" "nvptx-nvidia-cuda" -fcuda-is-device -fsyntax-only -verify %s
#include "cuda_builtin_vars.h"
__attribute__((global))
void kernel(int *out) {
int i = 0;
out[i++] = threadIdx.x;
threadIdx.x = 0; // expected-error {{no setter defined for property 'x'}}
out[i++] = threadIdx.y;
threadIdx.y = 0; // expected-error {{no setter defined for property 'y'}}
out[i++] = threadIdx.z;
threadIdx.z = 0; // expected-error {{no setter defined for property 'z'}}
out[i++] = blockIdx.x;
blockIdx.x = 0; // expected-error {{no setter defined for property 'x'}}
out[i++] = blockIdx.y;
blockIdx.y = 0; // expected-error {{no setter defined for property 'y'}}
out[i++] = blockIdx.z;
blockIdx.z = 0; // expected-error {{no setter defined for property 'z'}}
out[i++] = blockDim.x;
blockDim.x = 0; // expected-error {{no setter defined for property 'x'}}
out[i++] = blockDim.y;
blockDim.y = 0; // expected-error {{no setter defined for property 'y'}}
out[i++] = blockDim.z;
blockDim.z = 0; // expected-error {{no setter defined for property 'z'}}
out[i++] = gridDim.x;
gridDim.x = 0; // expected-error {{no setter defined for property 'x'}}
out[i++] = gridDim.y;
gridDim.y = 0; // expected-error {{no setter defined for property 'y'}}
out[i++] = gridDim.z;
gridDim.z = 0; // expected-error {{no setter defined for property 'z'}}
out[i++] = warpSize;
warpSize = 0; // expected-error {{cannot assign to variable 'warpSize' with const-qualified type 'const int'}}
// expected-note@cuda_builtin_vars.h:104 {{variable 'warpSize' declared const here}}
// Make sure we can't construct or assign to the special variables.
__cuda_builtin_threadIdx_t x; // expected-error {{calling a private constructor of class '__cuda_builtin_threadIdx_t'}}
// expected-note@cuda_builtin_vars.h:67 {{declared private here}}
__cuda_builtin_threadIdx_t y = threadIdx; // expected-error {{calling a private constructor of class '__cuda_builtin_threadIdx_t'}}
// expected-note@cuda_builtin_vars.h:67 {{declared private here}}
threadIdx = threadIdx; // expected-error {{'operator=' is a private member of '__cuda_builtin_threadIdx_t'}}
// expected-note@cuda_builtin_vars.h:67 {{declared private here}}
void *ptr = &threadIdx; // expected-error {{'operator&' is a private member of '__cuda_builtin_threadIdx_t'}}
// expected-note@cuda_builtin_vars.h:67 {{declared private here}}
// Following line should've caused an error as one is not allowed to
// take address of a built-in variable in CUDA. Alas there's no way
// to prevent getting address of a 'const int', so the line
// currently compiles without errors or warnings.
const void *wsptr = &warpSize;
}