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//===----- CGOpenMPRuntimeNVPTX.h - Interface to OpenMP NVPTX Runtimes ----===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This provides a class for OpenMP runtime code generation specialized to NVPTX
// targets.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_LIB_CODEGEN_CGOPENMPRUNTIMENVPTX_H
#define LLVM_CLANG_LIB_CODEGEN_CGOPENMPRUNTIMENVPTX_H
#include "CGOpenMPRuntime.h"
#include "CodeGenFunction.h"
#include "clang/AST/StmtOpenMP.h"
#include "llvm/IR/CallSite.h"
namespace clang {
namespace CodeGen {
class CGOpenMPRuntimeNVPTX : public CGOpenMPRuntime {
public:
class EntryFunctionState {
public:
llvm::BasicBlock *ExitBB;
EntryFunctionState() : ExitBB(nullptr){};
};
class WorkerFunctionState {
public:
llvm::Function *WorkerFn;
const CGFunctionInfo *CGFI;
WorkerFunctionState(CodeGenModule &CGM);
private:
void createWorkerFunction(CodeGenModule &CGM);
};
/// \brief Helper for target entry function. Guide the master and worker
/// threads to their respective locations.
void emitEntryHeader(CodeGenFunction &CGF, EntryFunctionState &EST,
WorkerFunctionState &WST);
/// \brief Signal termination of OMP execution.
void emitEntryFooter(CodeGenFunction &CGF, EntryFunctionState &EST);
private:
//
// NVPTX calls.
//
/// \brief Get the GPU warp size.
llvm::Value *getNVPTXWarpSize(CodeGenFunction &CGF);
/// \brief Get the id of the current thread on the GPU.
llvm::Value *getNVPTXThreadID(CodeGenFunction &CGF);
// \brief Get the maximum number of threads in a block of the GPU.
llvm::Value *getNVPTXNumThreads(CodeGenFunction &CGF);
/// \brief Get barrier to synchronize all threads in a block.
void getNVPTXCTABarrier(CodeGenFunction &CGF);
// \brief Synchronize all GPU threads in a block.
void syncCTAThreads(CodeGenFunction &CGF);
//
// OMP calls.
//
/// \brief Get the thread id of the OMP master thread.
/// The master thread id is the first thread (lane) of the last warp in the
/// GPU block. Warp size is assumed to be some power of 2.
/// Thread id is 0 indexed.
/// E.g: If NumThreads is 33, master id is 32.
/// If NumThreads is 64, master id is 32.
/// If NumThreads is 1024, master id is 992.
llvm::Value *getMasterThreadID(CodeGenFunction &CGF);
//
// Private state and methods.
//
// Master-worker control state.
// Number of requested OMP threads in parallel region.
llvm::GlobalVariable *ActiveWorkers;
// Outlined function for the workers to execute.
llvm::GlobalVariable *WorkID;
/// \brief Initialize master-worker control state.
void initializeEnvironment();
/// \brief Emit the worker function for the current target region.
void emitWorkerFunction(WorkerFunctionState &WST);
/// \brief Helper for worker function. Emit body of worker loop.
void emitWorkerLoop(CodeGenFunction &CGF, WorkerFunctionState &WST);
/// \brief Returns specified OpenMP runtime function for the current OpenMP
/// implementation. Specialized for the NVPTX device.
/// \param Function OpenMP runtime function.
/// \return Specified function.
llvm::Constant *createNVPTXRuntimeFunction(unsigned Function);
//
// Base class overrides.
//
/// \brief Creates offloading entry for the provided entry ID \a ID,
/// address \a Addr and size \a Size.
void createOffloadEntry(llvm::Constant *ID, llvm::Constant *Addr,
uint64_t Size) override;
/// \brief Emit outlined function for 'target' directive on the NVPTX
/// device.
/// \param D Directive to emit.
/// \param ParentName Name of the function that encloses the target region.
/// \param OutlinedFn Outlined function value to be defined by this call.
/// \param OutlinedFnID Outlined function ID value to be defined by this call.
/// \param IsOffloadEntry True if the outlined function is an offload entry.
/// An outlined function may not be an entry if, e.g. the if clause always
/// evaluates to false.
void emitTargetOutlinedFunction(const OMPExecutableDirective &D,
StringRef ParentName,
llvm::Function *&OutlinedFn,
llvm::Constant *&OutlinedFnID,
bool IsOffloadEntry,
const RegionCodeGenTy &CodeGen) override;
public:
explicit CGOpenMPRuntimeNVPTX(CodeGenModule &CGM);
};
} // CodeGen namespace.
} // clang namespace.
#endif // LLVM_CLANG_LIB_CODEGEN_CGOPENMPRUNTIMENVPTX_H
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