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[OpenMP][AMDGCN] Support OpenMP offloading for AMDGCN architecture - Part 2 

Summary:
New file include to support platform dependent grid constants. It will be
used by clang, libomptarget plugins, and deviceRTLs to access constant
values consistently and with fast access in the deviceRTLs.

Originally authored by Greg Rodgers (@gregrodgers).

Reviewers: arsenm, sameerds, jdoerfert, yaxunl, b-sumner, scchan, JonChesterfield

Reviewed By: arsenm

Subscribers: llvm-commits, pdhaliwal, jholewinski, jvesely, wdng, nhaehnle, guansong, kerbowa, sstefan1, cfe-commits, ronlieb, gregrodgers

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D80917
This commit is contained in:
Saiyedul Islam 2020-06-10 17:58:15 +00:00
parent 0f04f10453
commit 4022bc2a6c
4 changed files with 146 additions and 0 deletions
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11
clang/include/clang/Basic/TargetInfo.h
View File

@ -15,6 +15,7 @@
#define LLVM_CLANG_BASIC_TARGETINFO_H
#include "clang/Basic/AddressSpaces.h"
#include "clang/Basic/CodeGenOptions.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/Specifiers.h"
@ -29,6 +30,7 @@
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Frontend/OpenMP/OMPGridValues.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/VersionTuple.h"
#include <cassert>
@ -198,6 +200,9 @@ protected:
unsigned char RegParmMax, SSERegParmMax;
TargetCXXABI TheCXXABI;
const LangASMap *AddrSpaceMap;
const unsigned *GridValues =
nullptr; // Array of target-specific GPU grid values that must be
// consistent between host RTL (plugin), device RTL, and clang.
mutable StringRef PlatformName;
mutable VersionTuple PlatformMinVersion;
@ -1321,6 +1326,12 @@ public:
return LangAS::Default;
}
/// Return a target-specific GPU grid value based on the GVIDX enum \param gv
unsigned getGridValue(llvm::omp::GVIDX gv) const {
assert(GridValues != nullptr && "GridValues not initialized");
return GridValues[gv];
}
/// Retrieve the name of the platform as it is used in the
/// availability attribute.
StringRef getPlatformName() const { return PlatformName; }

2
clang/lib/Basic/Targets/AMDGPU.cpp
View File

@ -17,6 +17,7 @@
#include "clang/Basic/MacroBuilder.h"
#include "clang/Basic/TargetBuiltins.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Frontend/OpenMP/OMPGridValues.h"
#include "llvm/IR/DataLayout.h"
using namespace clang;
@ -286,6 +287,7 @@ AMDGPUTargetInfo::AMDGPUTargetInfo(const llvm::Triple &Triple,
resetDataLayout(isAMDGCN(getTriple()) ? DataLayoutStringAMDGCN
: DataLayoutStringR600);
assert(DataLayout->getAllocaAddrSpace() == Private);
GridValues = llvm::omp::AMDGPUGpuGridValues;
setAddressSpaceMap(Triple.getOS() == llvm::Triple::Mesa3D ||
!isAMDGCN(Triple));

2
clang/lib/Basic/Targets/NVPTX.cpp
View File

@ -16,6 +16,7 @@
#include "clang/Basic/MacroBuilder.h"
#include "clang/Basic/TargetBuiltins.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Frontend/OpenMP/OMPGridValues.h"
using namespace clang;
using namespace clang::targets;
@ -62,6 +63,7 @@ NVPTXTargetInfo::NVPTXTargetInfo(const llvm::Triple &Triple,
TLSSupported = false;
VLASupported = false;
AddrSpaceMap = &NVPTXAddrSpaceMap;
GridValues = llvm::omp::NVPTXGpuGridValues;
UseAddrSpaceMapMangling = true;
// Define available target features

131
llvm/include/llvm/Frontend/OpenMP/OMPGridValues.h Normal file
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@ -0,0 +1,131 @@
//====--- OMPGridValues.h - Language-specific address spaces --*- C++ -*-====//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief Provides definitions for Target specific Grid Values
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_OPENMP_GRIDVALUES_H
#define LLVM_OPENMP_GRIDVALUES_H
namespace llvm {
namespace omp {
/// \brief Defines various target-specific GPU grid values that must be
/// consistent between host RTL (plugin), device RTL, and clang.
/// We can change grid values for a "fat" binary so that different
/// passes get the correct values when generating code for a
/// multi-target binary. Both amdgcn and nvptx values are stored in
/// this file. In the future, should there be differences between GPUs
/// of the same architecture, then simply make a different array and
/// use the new array name.
///
/// Example usage in clang:
/// const unsigned slot_size = ctx.GetTargetInfo().getGridValue(GV_Warp_Size);
///
/// Example usage in libomptarget/deviceRTLs:
/// #include "OMPGridValues.h"
/// #ifdef __AMDGPU__
/// #define GRIDVAL AMDGPUGpuGridValues
/// #else
/// #define GRIDVAL NVPTXGpuGridValues
/// #endif
/// ... Then use this reference for GV_Warp_Size in the deviceRTL source.
/// GRIDVAL[GV_Warp_Size]
///
/// Example usage in libomptarget hsa plugin:
/// #include "OMPGridValues.h"
/// #define GRIDVAL AMDGPUGpuGridValues
/// ... Then use this reference to access GV_Warp_Size in the hsa plugin.
/// GRIDVAL[GV_Warp_Size]
///
/// Example usage in libomptarget cuda plugin:
/// #include "OMPGridValues.h"
/// #define GRIDVAL NVPTXGpuGridValues
/// ... Then use this reference to access GV_Warp_Size in the cuda plugin.
/// GRIDVAL[GV_Warp_Size]
///
enum GVIDX {
/// The maximum number of workers in a kernel.
/// (THREAD_ABSOLUTE_LIMIT) - (GV_Warp_Size), might be issue for blockDim.z
GV_Threads,
/// The size reserved for data in a shared memory slot.
GV_Slot_Size,
/// The default value of maximum number of threads in a worker warp.
GV_Warp_Size,
/// Alternate warp size for some AMDGCN architectures. Same as GV_Warp_Size
/// for NVPTX.
GV_Warp_Size_32,
/// The number of bits required to represent the max number of threads in warp
GV_Warp_Size_Log2,
/// GV_Warp_Size * GV_Slot_Size,
GV_Warp_Slot_Size,
/// the maximum number of teams.
GV_Max_Teams,
/// Global Memory Alignment
GV_Mem_Align,
/// (~0u >> (GV_Warp_Size - GV_Warp_Size_Log2))
GV_Warp_Size_Log2_Mask,
// An alternative to the heavy data sharing infrastructure that uses global
// memory is one that uses device __shared__ memory. The amount of such space
// (in bytes) reserved by the OpenMP runtime is noted here.
GV_SimpleBufferSize,
// The absolute maximum team size for a working group
GV_Max_WG_Size,
// The default maximum team size for a working group
GV_Default_WG_Size,
// This is GV_Max_WG_Size / GV_WarpSize. 32 for NVPTX and 16 for AMDGCN.
GV_Max_Warp_Number,
/// The slot size that should be reserved for a working warp.
/// (~0u >> (GV_Warp_Size - GV_Warp_Size_Log2))
GV_Warp_Size_Log2_MaskL
};
/// For AMDGPU GPUs
static constexpr unsigned AMDGPUGpuGridValues[] = {
448, // GV_Threads
256, // GV_Slot_Size
64, // GV_Warp_Size
32, // GV_Warp_Size_32
6, // GV_Warp_Size_Log2
64 * 256, // GV_Warp_Slot_Size
128, // GV_Max_Teams
256, // GV_Mem_Align
63, // GV_Warp_Size_Log2_Mask
896, // GV_SimpleBufferSize
1024, // GV_Max_WG_Size,
256, // GV_Defaut_WG_Size
1024 / 64, // GV_Max_WG_Size / GV_WarpSize
63 // GV_Warp_Size_Log2_MaskL
};
/// For Nvidia GPUs
static constexpr unsigned NVPTXGpuGridValues[] = {
992, // GV_Threads
256, // GV_Slot_Size
32, // GV_Warp_Size
32, // GV_Warp_Size_32
5, // GV_Warp_Size_Log2
32 * 256, // GV_Warp_Slot_Size
1024, // GV_Max_Teams
256, // GV_Mem_Align
(~0u >> (32 - 5)), // GV_Warp_Size_Log2_Mask
896, // GV_SimpleBufferSize
1024, // GV_Max_WG_Size
128, // GV_Defaut_WG_Size
1024 / 32, // GV_Max_WG_Size / GV_WarpSize
31 // GV_Warp_Size_Log2_MaskL
};
} // namespace omp
} // namespace llvm
#endif // LLVM_OPENMP_GRIDVALUES_H