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CGOpenMPRuntimeNVPTX.cpp
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CGOpenMPRuntimeNVPTX.cpp
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//===---- CGOpenMPRuntimeNVPTX.cpp - 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.
//
//===----------------------------------------------------------------------===//
#include "CGOpenMPRuntimeNVPTX.h"
#include "clang/AST/DeclOpenMP.h"
#include "CodeGenFunction.h"
#include "clang/AST/StmtOpenMP.h"
using namespace clang;
using namespace CodeGen;
namespace {
enum OpenMPRTLFunctionNVPTX {
/// \brief Call to void __kmpc_kernel_init(kmp_int32 thread_limit,
/// int16_t RequiresOMPRuntime);
OMPRTL_NVPTX__kmpc_kernel_init,
/// \brief Call to void __kmpc_kernel_deinit(int16_t IsOMPRuntimeInitialized);
OMPRTL_NVPTX__kmpc_kernel_deinit,
/// \brief Call to void __kmpc_spmd_kernel_init(kmp_int32 thread_limit,
/// int16_t RequiresOMPRuntime, int16_t RequiresDataSharing);
OMPRTL_NVPTX__kmpc_spmd_kernel_init,
/// \brief Call to void __kmpc_spmd_kernel_deinit();
OMPRTL_NVPTX__kmpc_spmd_kernel_deinit,
/// \brief Call to void __kmpc_kernel_prepare_parallel(void
/// *outlined_function, void ***args, kmp_int32 nArgs, int16_t
/// IsOMPRuntimeInitialized);
OMPRTL_NVPTX__kmpc_kernel_prepare_parallel,
/// \brief Call to bool __kmpc_kernel_parallel(void **outlined_function, void
/// ***args, int16_t IsOMPRuntimeInitialized);
OMPRTL_NVPTX__kmpc_kernel_parallel,
/// \brief Call to void __kmpc_kernel_end_parallel();
OMPRTL_NVPTX__kmpc_kernel_end_parallel,
/// Call to void __kmpc_serialized_parallel(ident_t *loc, kmp_int32
/// global_tid);
OMPRTL_NVPTX__kmpc_serialized_parallel,
/// Call to void __kmpc_end_serialized_parallel(ident_t *loc, kmp_int32
/// global_tid);
OMPRTL_NVPTX__kmpc_end_serialized_parallel,
/// \brief Call to int32_t __kmpc_shuffle_int32(int32_t element,
/// int16_t lane_offset, int16_t warp_size);
OMPRTL_NVPTX__kmpc_shuffle_int32,
/// \brief Call to int64_t __kmpc_shuffle_int64(int64_t element,
/// int16_t lane_offset, int16_t warp_size);
OMPRTL_NVPTX__kmpc_shuffle_int64,
/// \brief Call to __kmpc_nvptx_parallel_reduce_nowait(kmp_int32
/// global_tid, kmp_int32 num_vars, size_t reduce_size, void* reduce_data,
/// void (*kmp_ShuffleReductFctPtr)(void *rhsData, int16_t lane_id, int16_t
/// lane_offset, int16_t shortCircuit),
/// void (*kmp_InterWarpCopyFctPtr)(void* src, int32_t warp_num));
OMPRTL_NVPTX__kmpc_parallel_reduce_nowait,
/// \brief Call to __kmpc_nvptx_teams_reduce_nowait(int32_t global_tid,
/// int32_t num_vars, size_t reduce_size, void *reduce_data,
/// void (*kmp_ShuffleReductFctPtr)(void *rhs, int16_t lane_id, int16_t
/// lane_offset, int16_t shortCircuit),
/// void (*kmp_InterWarpCopyFctPtr)(void* src, int32_t warp_num),
/// void (*kmp_CopyToScratchpadFctPtr)(void *reduce_data, void * scratchpad,
/// int32_t index, int32_t width),
/// void (*kmp_LoadReduceFctPtr)(void *reduce_data, void * scratchpad, int32_t
/// index, int32_t width, int32_t reduce))
OMPRTL_NVPTX__kmpc_teams_reduce_nowait,
/// \brief Call to __kmpc_nvptx_end_reduce_nowait(int32_t global_tid);
OMPRTL_NVPTX__kmpc_end_reduce_nowait
};
/// Pre(post)-action for different OpenMP constructs specialized for NVPTX.
class NVPTXActionTy final : public PrePostActionTy {
llvm::Value *EnterCallee;
ArrayRef<llvm::Value *> EnterArgs;
llvm::Value *ExitCallee;
ArrayRef<llvm::Value *> ExitArgs;
bool Conditional;
llvm::BasicBlock *ContBlock = nullptr;
public:
NVPTXActionTy(llvm::Value *EnterCallee, ArrayRef<llvm::Value *> EnterArgs,
llvm::Value *ExitCallee, ArrayRef<llvm::Value *> ExitArgs,
bool Conditional = false)
: EnterCallee(EnterCallee), EnterArgs(EnterArgs), ExitCallee(ExitCallee),
ExitArgs(ExitArgs), Conditional(Conditional) {}
void Enter(CodeGenFunction &CGF) override {
llvm::Value *EnterRes = CGF.EmitRuntimeCall(EnterCallee, EnterArgs);
if (Conditional) {
llvm::Value *CallBool = CGF.Builder.CreateIsNotNull(EnterRes);
auto *ThenBlock = CGF.createBasicBlock("omp_if.then");
ContBlock = CGF.createBasicBlock("omp_if.end");
// Generate the branch (If-stmt)
CGF.Builder.CreateCondBr(CallBool, ThenBlock, ContBlock);
CGF.EmitBlock(ThenBlock);
}
}
void Done(CodeGenFunction &CGF) {
// Emit the rest of blocks/branches
CGF.EmitBranch(ContBlock);
CGF.EmitBlock(ContBlock, true);
}
void Exit(CodeGenFunction &CGF) override {
CGF.EmitRuntimeCall(ExitCallee, ExitArgs);
}
};
// A class to track the execution mode when codegening directives within
// a target region. The appropriate mode (generic/spmd) is set on entry
// to the target region and used by containing directives such as 'parallel'
// to emit optimized code.
class ExecutionModeRAII {
private:
CGOpenMPRuntimeNVPTX::ExecutionMode SavedMode;
CGOpenMPRuntimeNVPTX::ExecutionMode &Mode;
public:
ExecutionModeRAII(CGOpenMPRuntimeNVPTX::ExecutionMode &Mode,
CGOpenMPRuntimeNVPTX::ExecutionMode NewMode)
: Mode(Mode) {
SavedMode = Mode;
Mode = NewMode;
}
~ExecutionModeRAII() { Mode = SavedMode; }
};
/// GPU Configuration: This information can be derived from cuda registers,
/// however, providing compile time constants helps generate more efficient
/// code. For all practical purposes this is fine because the configuration
/// is the same for all known NVPTX architectures.
enum MachineConfiguration : unsigned {
WarpSize = 32,
/// Number of bits required to represent a lane identifier, which is
/// computed as log_2(WarpSize).
LaneIDBits = 5,
LaneIDMask = WarpSize - 1,
/// Global memory alignment for performance.
GlobalMemoryAlignment = 256,
};
enum NamedBarrier : unsigned {
/// Synchronize on this barrier #ID using a named barrier primitive.
/// Only the subset of active threads in a parallel region arrive at the
/// barrier.
NB_Parallel = 1,
};
} // anonymous namespace
/// Get the GPU warp size.
static llvm::Value *getNVPTXWarpSize(CodeGenFunction &CGF) {
return CGF.EmitRuntimeCall(
llvm::Intrinsic::getDeclaration(
&CGF.CGM.getModule(), llvm::Intrinsic::nvvm_read_ptx_sreg_warpsize),
"nvptx_warp_size");
}
/// Get the id of the current thread on the GPU.
static llvm::Value *getNVPTXThreadID(CodeGenFunction &CGF) {
return CGF.EmitRuntimeCall(
llvm::Intrinsic::getDeclaration(
&CGF.CGM.getModule(), llvm::Intrinsic::nvvm_read_ptx_sreg_tid_x),
"nvptx_tid");
}
/// Get the id of the warp in the block.
/// We assume that the warp size is 32, which is always the case
/// on the NVPTX device, to generate more efficient code.
static llvm::Value *getNVPTXWarpID(CodeGenFunction &CGF) {
CGBuilderTy &Bld = CGF.Builder;
return Bld.CreateAShr(getNVPTXThreadID(CGF), LaneIDBits, "nvptx_warp_id");
}
/// Get the id of the current lane in the Warp.
/// We assume that the warp size is 32, which is always the case
/// on the NVPTX device, to generate more efficient code.
static llvm::Value *getNVPTXLaneID(CodeGenFunction &CGF) {
CGBuilderTy &Bld = CGF.Builder;
return Bld.CreateAnd(getNVPTXThreadID(CGF), Bld.getInt32(LaneIDMask),
"nvptx_lane_id");
}
/// Get the maximum number of threads in a block of the GPU.
static llvm::Value *getNVPTXNumThreads(CodeGenFunction &CGF) {
return CGF.EmitRuntimeCall(
llvm::Intrinsic::getDeclaration(
&CGF.CGM.getModule(), llvm::Intrinsic::nvvm_read_ptx_sreg_ntid_x),
"nvptx_num_threads");
}
/// Get barrier to synchronize all threads in a block.
static void getNVPTXCTABarrier(CodeGenFunction &CGF) {
CGF.EmitRuntimeCall(llvm::Intrinsic::getDeclaration(
&CGF.CGM.getModule(), llvm::Intrinsic::nvvm_barrier0));
}
/// Get barrier #ID to synchronize selected (multiple of warp size) threads in
/// a CTA.
static void getNVPTXBarrier(CodeGenFunction &CGF, int ID,
llvm::Value *NumThreads) {
CGBuilderTy &Bld = CGF.Builder;
llvm::Value *Args[] = {Bld.getInt32(ID), NumThreads};
CGF.EmitRuntimeCall(llvm::Intrinsic::getDeclaration(
&CGF.CGM.getModule(), llvm::Intrinsic::nvvm_barrier),
Args);
}
/// Synchronize all GPU threads in a block.
static void syncCTAThreads(CodeGenFunction &CGF) { getNVPTXCTABarrier(CGF); }
/// Synchronize worker threads in a parallel region.
static void syncParallelThreads(CodeGenFunction &CGF, llvm::Value *NumThreads) {
return getNVPTXBarrier(CGF, NB_Parallel, NumThreads);
}
/// Get the value of the thread_limit clause in the teams directive.
/// For the 'generic' execution mode, the runtime encodes thread_limit in
/// the launch parameters, always starting thread_limit+warpSize threads per
/// CTA. The threads in the last warp are reserved for master execution.
/// For the 'spmd' execution mode, all threads in a CTA are part of the team.
static llvm::Value *getThreadLimit(CodeGenFunction &CGF,
bool IsInSpmdExecutionMode = false) {
CGBuilderTy &Bld = CGF.Builder;
return IsInSpmdExecutionMode
? getNVPTXNumThreads(CGF)
: Bld.CreateSub(getNVPTXNumThreads(CGF), getNVPTXWarpSize(CGF),
"thread_limit");
}
/// 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.
static llvm::Value *getMasterThreadID(CodeGenFunction &CGF) {
CGBuilderTy &Bld = CGF.Builder;
llvm::Value *NumThreads = getNVPTXNumThreads(CGF);
// We assume that the warp size is a power of 2.
llvm::Value *Mask = Bld.CreateSub(getNVPTXWarpSize(CGF), Bld.getInt32(1));
return Bld.CreateAnd(Bld.CreateSub(NumThreads, Bld.getInt32(1)),
Bld.CreateNot(Mask), "master_tid");
}
CGOpenMPRuntimeNVPTX::WorkerFunctionState::WorkerFunctionState(
CodeGenModule &CGM, SourceLocation Loc)
: WorkerFn(nullptr), CGFI(nullptr), Loc(Loc) {
createWorkerFunction(CGM);
}
void CGOpenMPRuntimeNVPTX::WorkerFunctionState::createWorkerFunction(
CodeGenModule &CGM) {
// Create an worker function with no arguments.
CGFI = &CGM.getTypes().arrangeNullaryFunction();
WorkerFn = llvm::Function::Create(
CGM.getTypes().GetFunctionType(*CGFI), llvm::GlobalValue::InternalLinkage,
/*placeholder=*/"_worker", &CGM.getModule());
CGM.SetInternalFunctionAttributes(/*D=*/nullptr, WorkerFn, *CGFI);
}
bool CGOpenMPRuntimeNVPTX::isInSpmdExecutionMode() const {
return CurrentExecutionMode == CGOpenMPRuntimeNVPTX::ExecutionMode::Spmd;
}
static CGOpenMPRuntimeNVPTX::ExecutionMode
getExecutionMode(CodeGenModule &CGM) {
return CGM.getLangOpts().OpenMPCUDAMode
? CGOpenMPRuntimeNVPTX::ExecutionMode::Spmd
: CGOpenMPRuntimeNVPTX::ExecutionMode::Generic;
}
void CGOpenMPRuntimeNVPTX::emitGenericKernel(const OMPExecutableDirective &D,
StringRef ParentName,
llvm::Function *&OutlinedFn,
llvm::Constant *&OutlinedFnID,
bool IsOffloadEntry,
const RegionCodeGenTy &CodeGen) {
ExecutionModeRAII ModeRAII(CurrentExecutionMode,
CGOpenMPRuntimeNVPTX::ExecutionMode::Generic);
EntryFunctionState EST;
WorkerFunctionState WST(CGM, D.getLocStart());
Work.clear();
WrapperFunctionsMap.clear();
// Emit target region as a standalone region.
class NVPTXPrePostActionTy : public PrePostActionTy {
CGOpenMPRuntimeNVPTX::EntryFunctionState &EST;
CGOpenMPRuntimeNVPTX::WorkerFunctionState &WST;
public:
NVPTXPrePostActionTy(CGOpenMPRuntimeNVPTX::EntryFunctionState &EST,
CGOpenMPRuntimeNVPTX::WorkerFunctionState &WST)
: EST(EST), WST(WST) {}
void Enter(CodeGenFunction &CGF) override {
static_cast<CGOpenMPRuntimeNVPTX &>(CGF.CGM.getOpenMPRuntime())
.emitGenericEntryHeader(CGF, EST, WST);
}
void Exit(CodeGenFunction &CGF) override {
static_cast<CGOpenMPRuntimeNVPTX &>(CGF.CGM.getOpenMPRuntime())
.emitGenericEntryFooter(CGF, EST);
}
} Action(EST, WST);
CodeGen.setAction(Action);
emitTargetOutlinedFunctionHelper(D, ParentName, OutlinedFn, OutlinedFnID,
IsOffloadEntry, CodeGen);
// Now change the name of the worker function to correspond to this target
// region's entry function.
WST.WorkerFn->setName(OutlinedFn->getName() + "_worker");
// Create the worker function
emitWorkerFunction(WST);
}
// Setup NVPTX threads for master-worker OpenMP scheme.
void CGOpenMPRuntimeNVPTX::emitGenericEntryHeader(CodeGenFunction &CGF,
EntryFunctionState &EST,
WorkerFunctionState &WST) {
CGBuilderTy &Bld = CGF.Builder;
llvm::BasicBlock *WorkerBB = CGF.createBasicBlock(".worker");
llvm::BasicBlock *MasterCheckBB = CGF.createBasicBlock(".mastercheck");
llvm::BasicBlock *MasterBB = CGF.createBasicBlock(".master");
EST.ExitBB = CGF.createBasicBlock(".exit");
auto *IsWorker =
Bld.CreateICmpULT(getNVPTXThreadID(CGF), getThreadLimit(CGF));
Bld.CreateCondBr(IsWorker, WorkerBB, MasterCheckBB);
CGF.EmitBlock(WorkerBB);
emitOutlinedFunctionCall(CGF, WST.Loc, WST.WorkerFn);
CGF.EmitBranch(EST.ExitBB);
CGF.EmitBlock(MasterCheckBB);
auto *IsMaster =
Bld.CreateICmpEQ(getNVPTXThreadID(CGF), getMasterThreadID(CGF));
Bld.CreateCondBr(IsMaster, MasterBB, EST.ExitBB);
CGF.EmitBlock(MasterBB);
// First action in sequential region:
// Initialize the state of the OpenMP runtime library on the GPU.
// TODO: Optimize runtime initialization and pass in correct value.
llvm::Value *Args[] = {getThreadLimit(CGF),
Bld.getInt16(/*RequiresOMPRuntime=*/1)};
CGF.EmitRuntimeCall(
createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_kernel_init), Args);
}
void CGOpenMPRuntimeNVPTX::emitGenericEntryFooter(CodeGenFunction &CGF,
EntryFunctionState &EST) {
if (!EST.ExitBB)
EST.ExitBB = CGF.createBasicBlock(".exit");
llvm::BasicBlock *TerminateBB = CGF.createBasicBlock(".termination.notifier");
CGF.EmitBranch(TerminateBB);
CGF.EmitBlock(TerminateBB);
// Signal termination condition.
// TODO: Optimize runtime initialization and pass in correct value.
llvm::Value *Args[] = {CGF.Builder.getInt16(/*IsOMPRuntimeInitialized=*/1)};
CGF.EmitRuntimeCall(
createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_kernel_deinit), Args);
// Barrier to terminate worker threads.
syncCTAThreads(CGF);
// Master thread jumps to exit point.
CGF.EmitBranch(EST.ExitBB);
CGF.EmitBlock(EST.ExitBB);
EST.ExitBB = nullptr;
}
void CGOpenMPRuntimeNVPTX::emitSpmdKernel(const OMPExecutableDirective &D,
StringRef ParentName,
llvm::Function *&OutlinedFn,
llvm::Constant *&OutlinedFnID,
bool IsOffloadEntry,
const RegionCodeGenTy &CodeGen) {
ExecutionModeRAII ModeRAII(CurrentExecutionMode,
CGOpenMPRuntimeNVPTX::ExecutionMode::Spmd);
EntryFunctionState EST;
// Emit target region as a standalone region.
class NVPTXPrePostActionTy : public PrePostActionTy {
CGOpenMPRuntimeNVPTX &RT;
CGOpenMPRuntimeNVPTX::EntryFunctionState &EST;
const OMPExecutableDirective &D;
public:
NVPTXPrePostActionTy(CGOpenMPRuntimeNVPTX &RT,
CGOpenMPRuntimeNVPTX::EntryFunctionState &EST,
const OMPExecutableDirective &D)
: RT(RT), EST(EST), D(D) {}
void Enter(CodeGenFunction &CGF) override {
RT.emitSpmdEntryHeader(CGF, EST, D);
}
void Exit(CodeGenFunction &CGF) override {
RT.emitSpmdEntryFooter(CGF, EST);
}
} Action(*this, EST, D);
CodeGen.setAction(Action);
emitTargetOutlinedFunctionHelper(D, ParentName, OutlinedFn, OutlinedFnID,
IsOffloadEntry, CodeGen);
}
void CGOpenMPRuntimeNVPTX::emitSpmdEntryHeader(
CodeGenFunction &CGF, EntryFunctionState &EST,
const OMPExecutableDirective &D) {
auto &Bld = CGF.Builder;
// Setup BBs in entry function.
llvm::BasicBlock *ExecuteBB = CGF.createBasicBlock(".execute");
EST.ExitBB = CGF.createBasicBlock(".exit");
// Initialize the OMP state in the runtime; called by all active threads.
// TODO: Set RequiresOMPRuntime and RequiresDataSharing parameters
// based on code analysis of the target region.
llvm::Value *Args[] = {getThreadLimit(CGF, /*IsInSpmdExecutionMode=*/true),
/*RequiresOMPRuntime=*/Bld.getInt16(1),
/*RequiresDataSharing=*/Bld.getInt16(1)};
CGF.EmitRuntimeCall(
createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_spmd_kernel_init), Args);
CGF.EmitBranch(ExecuteBB);
CGF.EmitBlock(ExecuteBB);
}
void CGOpenMPRuntimeNVPTX::emitSpmdEntryFooter(CodeGenFunction &CGF,
EntryFunctionState &EST) {
if (!EST.ExitBB)
EST.ExitBB = CGF.createBasicBlock(".exit");
llvm::BasicBlock *OMPDeInitBB = CGF.createBasicBlock(".omp.deinit");
CGF.EmitBranch(OMPDeInitBB);
CGF.EmitBlock(OMPDeInitBB);
// DeInitialize the OMP state in the runtime; called by all active threads.
CGF.EmitRuntimeCall(
createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_spmd_kernel_deinit), None);
CGF.EmitBranch(EST.ExitBB);
CGF.EmitBlock(EST.ExitBB);
EST.ExitBB = nullptr;
}
// Create a unique global variable to indicate the execution mode of this target
// region. The execution mode is either 'generic', or 'spmd' depending on the
// target directive. This variable is picked up by the offload library to setup
// the device appropriately before kernel launch. If the execution mode is
// 'generic', the runtime reserves one warp for the master, otherwise, all
// warps participate in parallel work.
static void setPropertyExecutionMode(CodeGenModule &CGM, StringRef Name,
CGOpenMPRuntimeNVPTX::ExecutionMode Mode) {
(void)new llvm::GlobalVariable(
CGM.getModule(), CGM.Int8Ty, /*isConstant=*/true,
llvm::GlobalValue::WeakAnyLinkage,
llvm::ConstantInt::get(CGM.Int8Ty, Mode), Name + Twine("_exec_mode"));
}
void CGOpenMPRuntimeNVPTX::emitWorkerFunction(WorkerFunctionState &WST) {
ASTContext &Ctx = CGM.getContext();
CodeGenFunction CGF(CGM, /*suppressNewContext=*/true);
CGF.StartFunction(GlobalDecl(), Ctx.VoidTy, WST.WorkerFn, *WST.CGFI, {},
WST.Loc, WST.Loc);
emitWorkerLoop(CGF, WST);
CGF.FinishFunction();
}
void CGOpenMPRuntimeNVPTX::emitWorkerLoop(CodeGenFunction &CGF,
WorkerFunctionState &WST) {
//
// The workers enter this loop and wait for parallel work from the master.
// When the master encounters a parallel region it sets up the work + variable
// arguments, and wakes up the workers. The workers first check to see if
// they are required for the parallel region, i.e., within the # of requested
// parallel threads. The activated workers load the variable arguments and
// execute the parallel work.
//
CGBuilderTy &Bld = CGF.Builder;
llvm::BasicBlock *AwaitBB = CGF.createBasicBlock(".await.work");
llvm::BasicBlock *SelectWorkersBB = CGF.createBasicBlock(".select.workers");
llvm::BasicBlock *ExecuteBB = CGF.createBasicBlock(".execute.parallel");
llvm::BasicBlock *TerminateBB = CGF.createBasicBlock(".terminate.parallel");
llvm::BasicBlock *BarrierBB = CGF.createBasicBlock(".barrier.parallel");
llvm::BasicBlock *ExitBB = CGF.createBasicBlock(".exit");
CGF.EmitBranch(AwaitBB);
// Workers wait for work from master.
CGF.EmitBlock(AwaitBB);
// Wait for parallel work
syncCTAThreads(CGF);
Address WorkFn =
CGF.CreateDefaultAlignTempAlloca(CGF.Int8PtrTy, /*Name=*/"work_fn");
Address ExecStatus =
CGF.CreateDefaultAlignTempAlloca(CGF.Int8Ty, /*Name=*/"exec_status");
CGF.InitTempAlloca(ExecStatus, Bld.getInt8(/*C=*/0));
CGF.InitTempAlloca(WorkFn, llvm::Constant::getNullValue(CGF.Int8PtrTy));
// Set up shared arguments
Address SharedArgs =
CGF.CreateDefaultAlignTempAlloca(CGF.Int8PtrPtrTy, "shared_args");
// TODO: Optimize runtime initialization and pass in correct value.
llvm::Value *Args[] = {WorkFn.getPointer(), SharedArgs.getPointer(),
/*RequiresOMPRuntime=*/Bld.getInt16(1)};
llvm::Value *Ret = CGF.EmitRuntimeCall(
createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_kernel_parallel), Args);
Bld.CreateStore(Bld.CreateZExt(Ret, CGF.Int8Ty), ExecStatus);
// On termination condition (workid == 0), exit loop.
llvm::Value *ShouldTerminate =
Bld.CreateIsNull(Bld.CreateLoad(WorkFn), "should_terminate");
Bld.CreateCondBr(ShouldTerminate, ExitBB, SelectWorkersBB);
// Activate requested workers.
CGF.EmitBlock(SelectWorkersBB);
llvm::Value *IsActive =
Bld.CreateIsNotNull(Bld.CreateLoad(ExecStatus), "is_active");
Bld.CreateCondBr(IsActive, ExecuteBB, BarrierBB);
// Signal start of parallel region.
CGF.EmitBlock(ExecuteBB);
// Current context
ASTContext &Ctx = CGF.getContext();
// Process work items: outlined parallel functions.
for (auto *W : Work) {
// Try to match this outlined function.
auto *ID = Bld.CreatePointerBitCastOrAddrSpaceCast(W, CGM.Int8PtrTy);
llvm::Value *WorkFnMatch =
Bld.CreateICmpEQ(Bld.CreateLoad(WorkFn), ID, "work_match");
llvm::BasicBlock *ExecuteFNBB = CGF.createBasicBlock(".execute.fn");
llvm::BasicBlock *CheckNextBB = CGF.createBasicBlock(".check.next");
Bld.CreateCondBr(WorkFnMatch, ExecuteFNBB, CheckNextBB);
// Execute this outlined function.
CGF.EmitBlock(ExecuteFNBB);
// Insert call to work function via shared wrapper. The shared
// wrapper takes exactly three arguments:
// - the parallelism level;
// - the master thread ID;
// - the list of references to shared arguments.
//
// TODO: Assert that the function is a wrapper function.s
Address Capture = CGF.EmitLoadOfPointer(SharedArgs,
Ctx.getPointerType(
Ctx.getPointerType(Ctx.VoidPtrTy)).castAs<PointerType>());
emitOutlinedFunctionCall(CGF, WST.Loc, W,
{Bld.getInt16(/*ParallelLevel=*/0),
getMasterThreadID(CGF), Capture.getPointer()});
// Go to end of parallel region.
CGF.EmitBranch(TerminateBB);
CGF.EmitBlock(CheckNextBB);
}
// Signal end of parallel region.
CGF.EmitBlock(TerminateBB);
CGF.EmitRuntimeCall(
createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_kernel_end_parallel),
llvm::None);
CGF.EmitBranch(BarrierBB);
// All active and inactive workers wait at a barrier after parallel region.
CGF.EmitBlock(BarrierBB);
// Barrier after parallel region.
syncCTAThreads(CGF);
CGF.EmitBranch(AwaitBB);
// Exit target region.
CGF.EmitBlock(ExitBB);
}
/// \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 *
CGOpenMPRuntimeNVPTX::createNVPTXRuntimeFunction(unsigned Function) {
llvm::Constant *RTLFn = nullptr;
switch (static_cast<OpenMPRTLFunctionNVPTX>(Function)) {
case OMPRTL_NVPTX__kmpc_kernel_init: {
// Build void __kmpc_kernel_init(kmp_int32 thread_limit, int16_t
// RequiresOMPRuntime);
llvm::Type *TypeParams[] = {CGM.Int32Ty, CGM.Int16Ty};
llvm::FunctionType *FnTy =
llvm::FunctionType::get(CGM.VoidTy, TypeParams, /*isVarArg*/ false);
RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_kernel_init");
break;
}
case OMPRTL_NVPTX__kmpc_kernel_deinit: {
// Build void __kmpc_kernel_deinit(int16_t IsOMPRuntimeInitialized);
llvm::Type *TypeParams[] = {CGM.Int16Ty};
llvm::FunctionType *FnTy =
llvm::FunctionType::get(CGM.VoidTy, TypeParams, /*isVarArg*/ false);
RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_kernel_deinit");
break;
}
case OMPRTL_NVPTX__kmpc_spmd_kernel_init: {
// Build void __kmpc_spmd_kernel_init(kmp_int32 thread_limit,
// int16_t RequiresOMPRuntime, int16_t RequiresDataSharing);
llvm::Type *TypeParams[] = {CGM.Int32Ty, CGM.Int16Ty, CGM.Int16Ty};
llvm::FunctionType *FnTy =
llvm::FunctionType::get(CGM.VoidTy, TypeParams, /*isVarArg*/ false);
RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_spmd_kernel_init");
break;
}
case OMPRTL_NVPTX__kmpc_spmd_kernel_deinit: {
// Build void __kmpc_spmd_kernel_deinit();
llvm::FunctionType *FnTy =
llvm::FunctionType::get(CGM.VoidTy, llvm::None, /*isVarArg*/ false);
RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_spmd_kernel_deinit");
break;
}
case OMPRTL_NVPTX__kmpc_kernel_prepare_parallel: {
/// Build void __kmpc_kernel_prepare_parallel(
/// void *outlined_function, void ***args, kmp_int32 nArgs, int16_t
/// IsOMPRuntimeInitialized);
llvm::Type *TypeParams[] = {CGM.Int8PtrTy,
CGM.Int8PtrPtrTy->getPointerTo(0), CGM.Int32Ty,
CGM.Int16Ty};
llvm::FunctionType *FnTy =
llvm::FunctionType::get(CGM.VoidTy, TypeParams, /*isVarArg*/ false);
RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_kernel_prepare_parallel");
break;
}
case OMPRTL_NVPTX__kmpc_kernel_parallel: {
/// Build bool __kmpc_kernel_parallel(void **outlined_function, void
/// ***args, int16_t IsOMPRuntimeInitialized);
llvm::Type *TypeParams[] = {CGM.Int8PtrPtrTy,
CGM.Int8PtrPtrTy->getPointerTo(0), CGM.Int16Ty};
llvm::Type *RetTy = CGM.getTypes().ConvertType(CGM.getContext().BoolTy);
llvm::FunctionType *FnTy =
llvm::FunctionType::get(RetTy, TypeParams, /*isVarArg*/ false);
RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_kernel_parallel");
break;
}
case OMPRTL_NVPTX__kmpc_kernel_end_parallel: {
/// Build void __kmpc_kernel_end_parallel();
llvm::FunctionType *FnTy =
llvm::FunctionType::get(CGM.VoidTy, llvm::None, /*isVarArg*/ false);
RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_kernel_end_parallel");
break;
}
case OMPRTL_NVPTX__kmpc_serialized_parallel: {
// Build void __kmpc_serialized_parallel(ident_t *loc, kmp_int32
// global_tid);
llvm::Type *TypeParams[] = {getIdentTyPointerTy(), CGM.Int32Ty};
llvm::FunctionType *FnTy =
llvm::FunctionType::get(CGM.VoidTy, TypeParams, /*isVarArg*/ false);
RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_serialized_parallel");
break;
}
case OMPRTL_NVPTX__kmpc_end_serialized_parallel: {
// Build void __kmpc_end_serialized_parallel(ident_t *loc, kmp_int32
// global_tid);
llvm::Type *TypeParams[] = {getIdentTyPointerTy(), CGM.Int32Ty};
llvm::FunctionType *FnTy =
llvm::FunctionType::get(CGM.VoidTy, TypeParams, /*isVarArg*/ false);
RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_end_serialized_parallel");
break;
}
case OMPRTL_NVPTX__kmpc_shuffle_int32: {
// Build int32_t __kmpc_shuffle_int32(int32_t element,
// int16_t lane_offset, int16_t warp_size);
llvm::Type *TypeParams[] = {CGM.Int32Ty, CGM.Int16Ty, CGM.Int16Ty};
llvm::FunctionType *FnTy =
llvm::FunctionType::get(CGM.Int32Ty, TypeParams, /*isVarArg*/ false);
RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_shuffle_int32");
break;
}
case OMPRTL_NVPTX__kmpc_shuffle_int64: {
// Build int64_t __kmpc_shuffle_int64(int64_t element,
// int16_t lane_offset, int16_t warp_size);
llvm::Type *TypeParams[] = {CGM.Int64Ty, CGM.Int16Ty, CGM.Int16Ty};
llvm::FunctionType *FnTy =
llvm::FunctionType::get(CGM.Int64Ty, TypeParams, /*isVarArg*/ false);
RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_shuffle_int64");
break;
}
case OMPRTL_NVPTX__kmpc_parallel_reduce_nowait: {
// Build int32_t kmpc_nvptx_parallel_reduce_nowait(kmp_int32 global_tid,
// kmp_int32 num_vars, size_t reduce_size, void* reduce_data,
// void (*kmp_ShuffleReductFctPtr)(void *rhsData, int16_t lane_id, int16_t
// lane_offset, int16_t Algorithm Version),
// void (*kmp_InterWarpCopyFctPtr)(void* src, int warp_num));
llvm::Type *ShuffleReduceTypeParams[] = {CGM.VoidPtrTy, CGM.Int16Ty,
CGM.Int16Ty, CGM.Int16Ty};
auto *ShuffleReduceFnTy =
llvm::FunctionType::get(CGM.VoidTy, ShuffleReduceTypeParams,
/*isVarArg=*/false);
llvm::Type *InterWarpCopyTypeParams[] = {CGM.VoidPtrTy, CGM.Int32Ty};
auto *InterWarpCopyFnTy =
llvm::FunctionType::get(CGM.VoidTy, InterWarpCopyTypeParams,
/*isVarArg=*/false);
llvm::Type *TypeParams[] = {CGM.Int32Ty,
CGM.Int32Ty,
CGM.SizeTy,
CGM.VoidPtrTy,
ShuffleReduceFnTy->getPointerTo(),
InterWarpCopyFnTy->getPointerTo()};
llvm::FunctionType *FnTy =
llvm::FunctionType::get(CGM.Int32Ty, TypeParams, /*isVarArg=*/false);
RTLFn = CGM.CreateRuntimeFunction(
FnTy, /*Name=*/"__kmpc_nvptx_parallel_reduce_nowait");
break;
}
case OMPRTL_NVPTX__kmpc_teams_reduce_nowait: {
// Build int32_t __kmpc_nvptx_teams_reduce_nowait(int32_t global_tid,
// int32_t num_vars, size_t reduce_size, void *reduce_data,
// void (*kmp_ShuffleReductFctPtr)(void *rhsData, int16_t lane_id, int16_t
// lane_offset, int16_t shortCircuit),
// void (*kmp_InterWarpCopyFctPtr)(void* src, int32_t warp_num),
// void (*kmp_CopyToScratchpadFctPtr)(void *reduce_data, void * scratchpad,
// int32_t index, int32_t width),
// void (*kmp_LoadReduceFctPtr)(void *reduce_data, void * scratchpad,
// int32_t index, int32_t width, int32_t reduce))
llvm::Type *ShuffleReduceTypeParams[] = {CGM.VoidPtrTy, CGM.Int16Ty,
CGM.Int16Ty, CGM.Int16Ty};
auto *ShuffleReduceFnTy =
llvm::FunctionType::get(CGM.VoidTy, ShuffleReduceTypeParams,
/*isVarArg=*/false);
llvm::Type *InterWarpCopyTypeParams[] = {CGM.VoidPtrTy, CGM.Int32Ty};
auto *InterWarpCopyFnTy =
llvm::FunctionType::get(CGM.VoidTy, InterWarpCopyTypeParams,
/*isVarArg=*/false);
llvm::Type *CopyToScratchpadTypeParams[] = {CGM.VoidPtrTy, CGM.VoidPtrTy,
CGM.Int32Ty, CGM.Int32Ty};
auto *CopyToScratchpadFnTy =
llvm::FunctionType::get(CGM.VoidTy, CopyToScratchpadTypeParams,
/*isVarArg=*/false);
llvm::Type *LoadReduceTypeParams[] = {
CGM.VoidPtrTy, CGM.VoidPtrTy, CGM.Int32Ty, CGM.Int32Ty, CGM.Int32Ty};
auto *LoadReduceFnTy =
llvm::FunctionType::get(CGM.VoidTy, LoadReduceTypeParams,
/*isVarArg=*/false);
llvm::Type *TypeParams[] = {CGM.Int32Ty,
CGM.Int32Ty,
CGM.SizeTy,
CGM.VoidPtrTy,
ShuffleReduceFnTy->getPointerTo(),
InterWarpCopyFnTy->getPointerTo(),
CopyToScratchpadFnTy->getPointerTo(),
LoadReduceFnTy->getPointerTo()};
llvm::FunctionType *FnTy =
llvm::FunctionType::get(CGM.Int32Ty, TypeParams, /*isVarArg=*/false);
RTLFn = CGM.CreateRuntimeFunction(
FnTy, /*Name=*/"__kmpc_nvptx_teams_reduce_nowait");
break;
}
case OMPRTL_NVPTX__kmpc_end_reduce_nowait: {
// Build __kmpc_end_reduce_nowait(kmp_int32 global_tid);
llvm::Type *TypeParams[] = {CGM.Int32Ty};
llvm::FunctionType *FnTy =
llvm::FunctionType::get(CGM.VoidTy, TypeParams, /*isVarArg=*/false);
RTLFn = CGM.CreateRuntimeFunction(
FnTy, /*Name=*/"__kmpc_nvptx_end_reduce_nowait");
break;
}
}
return RTLFn;
}
void CGOpenMPRuntimeNVPTX::createOffloadEntry(llvm::Constant *ID,
llvm::Constant *Addr,
uint64_t Size, int32_t) {
auto *F = dyn_cast<llvm::Function>(Addr);
// TODO: Add support for global variables on the device after declare target
// support.
if (!F)
return;
llvm::Module *M = F->getParent();
llvm::LLVMContext &Ctx = M->getContext();
// Get "nvvm.annotations" metadata node
llvm::NamedMDNode *MD = M->getOrInsertNamedMetadata("nvvm.annotations");
llvm::Metadata *MDVals[] = {
llvm::ConstantAsMetadata::get(F), llvm::MDString::get(Ctx, "kernel"),
llvm::ConstantAsMetadata::get(
llvm::ConstantInt::get(llvm::Type::getInt32Ty(Ctx), 1))};
// Append metadata to nvvm.annotations
MD->addOperand(llvm::MDNode::get(Ctx, MDVals));
}
void CGOpenMPRuntimeNVPTX::emitTargetOutlinedFunction(
const OMPExecutableDirective &D, StringRef ParentName,
llvm::Function *&OutlinedFn, llvm::Constant *&OutlinedFnID,
bool IsOffloadEntry, const RegionCodeGenTy &CodeGen) {
if (!IsOffloadEntry) // Nothing to do.
return;
assert(!ParentName.empty() && "Invalid target region parent name!");
CGOpenMPRuntimeNVPTX::ExecutionMode Mode = getExecutionMode(CGM);
switch (Mode) {
case CGOpenMPRuntimeNVPTX::ExecutionMode::Generic:
emitGenericKernel(D, ParentName, OutlinedFn, OutlinedFnID, IsOffloadEntry,
CodeGen);
break;
case CGOpenMPRuntimeNVPTX::ExecutionMode::Spmd:
emitSpmdKernel(D, ParentName, OutlinedFn, OutlinedFnID, IsOffloadEntry,
CodeGen);
break;
case CGOpenMPRuntimeNVPTX::ExecutionMode::Unknown:
llvm_unreachable(
"Unknown programming model for OpenMP directive on NVPTX target.");
}
setPropertyExecutionMode(CGM, OutlinedFn->getName(), Mode);
}
CGOpenMPRuntimeNVPTX::CGOpenMPRuntimeNVPTX(CodeGenModule &CGM)
: CGOpenMPRuntime(CGM), CurrentExecutionMode(ExecutionMode::Unknown) {
if (!CGM.getLangOpts().OpenMPIsDevice)
llvm_unreachable("OpenMP NVPTX can only handle device code.");
}
void CGOpenMPRuntimeNVPTX::emitProcBindClause(CodeGenFunction &CGF,
OpenMPProcBindClauseKind ProcBind,
SourceLocation Loc) {
// Do nothing in case of Spmd mode and L0 parallel.
// TODO: If in Spmd mode and L1 parallel emit the clause.
if (isInSpmdExecutionMode())
return;
CGOpenMPRuntime::emitProcBindClause(CGF, ProcBind, Loc);
}
void CGOpenMPRuntimeNVPTX::emitNumThreadsClause(CodeGenFunction &CGF,
llvm::Value *NumThreads,
SourceLocation Loc) {
// Do nothing in case of Spmd mode and L0 parallel.
// TODO: If in Spmd mode and L1 parallel emit the clause.
if (isInSpmdExecutionMode())
return;
CGOpenMPRuntime::emitNumThreadsClause(CGF, NumThreads, Loc);
}
void CGOpenMPRuntimeNVPTX::emitNumTeamsClause(CodeGenFunction &CGF,
const Expr *NumTeams,
const Expr *ThreadLimit,
SourceLocation Loc) {}
llvm::Value *CGOpenMPRuntimeNVPTX::emitParallelOutlinedFunction(
const OMPExecutableDirective &D, const VarDecl *ThreadIDVar,
OpenMPDirectiveKind InnermostKind, const RegionCodeGenTy &CodeGen) {
auto *OutlinedFun = cast<llvm::Function>(
CGOpenMPRuntime::emitParallelOutlinedFunction(
D, ThreadIDVar, InnermostKind, CodeGen));
if (!isInSpmdExecutionMode()) {
llvm::Function *WrapperFun =
createDataSharingWrapper(OutlinedFun, D);
WrapperFunctionsMap[OutlinedFun] = WrapperFun;
}
return OutlinedFun;
}
llvm::Value *CGOpenMPRuntimeNVPTX::emitTeamsOutlinedFunction(
const OMPExecutableDirective &D, const VarDecl *ThreadIDVar,
OpenMPDirectiveKind InnermostKind, const RegionCodeGenTy &CodeGen) {
llvm::Value *OutlinedFunVal = CGOpenMPRuntime::emitTeamsOutlinedFunction(
D, ThreadIDVar, InnermostKind, CodeGen);
llvm::Function *OutlinedFun = cast<llvm::Function>(OutlinedFunVal);
OutlinedFun->removeFnAttr(llvm::Attribute::NoInline);
OutlinedFun->removeFnAttr(llvm::Attribute::OptimizeNone);
OutlinedFun->addFnAttr(llvm::Attribute::AlwaysInline);
return OutlinedFun;
}
void CGOpenMPRuntimeNVPTX::emitTeamsCall(CodeGenFunction &CGF,
const OMPExecutableDirective &D,
SourceLocation Loc,
llvm::Value *OutlinedFn,
ArrayRef<llvm::Value *> CapturedVars) {
if (!CGF.HaveInsertPoint())
return;
Address ZeroAddr =
CGF.CreateTempAlloca(CGF.Int32Ty, CharUnits::fromQuantity(4),
/*Name*/ ".zero.addr");
CGF.InitTempAlloca(ZeroAddr, CGF.Builder.getInt32(/*C*/ 0));
llvm::SmallVector<llvm::Value *, 16> OutlinedFnArgs;
OutlinedFnArgs.push_back(ZeroAddr.getPointer());
OutlinedFnArgs.push_back(ZeroAddr.getPointer());
OutlinedFnArgs.append(CapturedVars.begin(), CapturedVars.end());
emitOutlinedFunctionCall(CGF, Loc, OutlinedFn, OutlinedFnArgs);
}
void CGOpenMPRuntimeNVPTX::emitParallelCall(
CodeGenFunction &CGF, SourceLocation Loc, llvm::Value *OutlinedFn,
ArrayRef<llvm::Value *> CapturedVars, const Expr *IfCond) {
if (!CGF.HaveInsertPoint())
return;
if (isInSpmdExecutionMode())
emitSpmdParallelCall(CGF, Loc, OutlinedFn, CapturedVars, IfCond);
else
emitGenericParallelCall(CGF, Loc, OutlinedFn, CapturedVars, IfCond);
}
void CGOpenMPRuntimeNVPTX::emitGenericParallelCall(
CodeGenFunction &CGF, SourceLocation Loc, llvm::Value *OutlinedFn,
ArrayRef<llvm::Value *> CapturedVars, const Expr *IfCond) {
llvm::Function *Fn = cast<llvm::Function>(OutlinedFn);
llvm::Function *WFn = WrapperFunctionsMap[Fn];
assert(WFn && "Wrapper function does not exist!");
// Force inline this outlined function at its call site.
Fn->setLinkage(llvm::GlobalValue::InternalLinkage);
auto &&L0ParallelGen = [this, WFn, &CapturedVars](CodeGenFunction &CGF,
PrePostActionTy &) {
CGBuilderTy &Bld = CGF.Builder;
llvm::Value *ID = Bld.CreateBitOrPointerCast(WFn, CGM.Int8PtrTy);
if (!CapturedVars.empty()) {
// There's somehting to share, add the attribute
CGF.CurFn->addFnAttr("has-nvptx-shared-depot");
// Prepare for parallel region. Indicate the outlined function.
Address SharedArgs =
CGF.CreateDefaultAlignTempAlloca(CGF.VoidPtrPtrTy,
"shared_args");
llvm::Value *SharedArgsPtr = SharedArgs.getPointer();
// TODO: Optimize runtime initialization and pass in correct value.
llvm::Value *Args[] = {ID, SharedArgsPtr,
Bld.getInt32(CapturedVars.size()),
/*RequiresOMPRuntime=*/Bld.getInt16(1)};
CGF.EmitRuntimeCall(
createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_kernel_prepare_parallel),
Args);
unsigned Idx = 0;
ASTContext &Ctx = CGF.getContext();
for (llvm::Value *V : CapturedVars) {
Address Dst = Bld.CreateConstInBoundsGEP(
CGF.EmitLoadOfPointer(SharedArgs,
Ctx.getPointerType(
Ctx.getPointerType(Ctx.VoidPtrTy)).castAs<PointerType>()),
Idx, CGF.getPointerSize());
llvm::Value *PtrV = Bld.CreateBitCast(V, CGF.VoidPtrTy);
CGF.EmitStoreOfScalar(PtrV, Dst, /*Volatile=*/false,
Ctx.getPointerType(Ctx.VoidPtrTy));
Idx++;
}
} else {
// TODO: Optimize runtime initialization and pass in correct value.
llvm::Value *Args[] = {
ID, llvm::ConstantPointerNull::get(CGF.VoidPtrPtrTy->getPointerTo(0)),
/*nArgs=*/Bld.getInt32(0), /*RequiresOMPRuntime=*/Bld.getInt16(1)};
CGF.EmitRuntimeCall(
createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_kernel_prepare_parallel),
Args);
}
// Activate workers. This barrier is used by the master to signal
// work for the workers.
syncCTAThreads(CGF);
// OpenMP [2.5, Parallel Construct, p.49]
// There is an implied barrier at the end of a parallel region. After the
// end of a parallel region, only the master thread of the team resumes
// execution of the enclosing task region.
//
// The master waits at this barrier until all workers are done.
syncCTAThreads(CGF);
// Remember for post-processing in worker loop.
Work.emplace_back(WFn);
};
auto *RTLoc = emitUpdateLocation(CGF, Loc);
auto *ThreadID = getThreadID(CGF, Loc);
llvm::Value *Args[] = {RTLoc, ThreadID};
auto &&SeqGen = [this, Fn, &CapturedVars, &Args, Loc](CodeGenFunction &CGF,
PrePostActionTy &) {