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llvm-project/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
Roger Ferrer Ibanez a82f35e176 [OpenMP] Lower taskwait using OpenMP IR Builder 
The code generation is exactly the same as it was.

But not that the special handling of untied tasks is still handled by
emitUntiedSwitch in clang.

Differential Revision: https://reviews.llvm.org/D69828
2020-02-14 09:53:02 +00:00

712 lines
27 KiB
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//===- OpenMPIRBuilder.cpp - Builder for LLVM-IR for OpenMP directives ----===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
/// \file
///
/// This file implements the OpenMPIRBuilder class, which is used as a
/// convenient way to create LLVM instructions for OpenMP directives.
///
//===----------------------------------------------------------------------===//
#include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Error.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/CodeExtractor.h"
#include <sstream>
#define DEBUG_TYPE "openmp-ir-builder"
using namespace llvm;
using namespace omp;
using namespace types;
static cl::opt<bool>
OptimisticAttributes("openmp-ir-builder-optimistic-attributes", cl::Hidden,
cl::desc("Use optimistic attributes describing "
"'as-if' properties of runtime calls."),
cl::init(false));
void OpenMPIRBuilder::addAttributes(omp::RuntimeFunction FnID, Function &Fn) {
LLVMContext &Ctx = Fn.getContext();
#define OMP_ATTRS_SET(VarName, AttrSet) AttributeSet VarName = AttrSet;
#include "llvm/Frontend/OpenMP/OMPKinds.def"
// Add attributes to the new declaration.
switch (FnID) {
#define OMP_RTL_ATTRS(Enum, FnAttrSet, RetAttrSet, ArgAttrSets) \
case Enum: \
Fn.setAttributes( \
AttributeList::get(Ctx, FnAttrSet, RetAttrSet, ArgAttrSets)); \
break;
#include "llvm/Frontend/OpenMP/OMPKinds.def"
default:
// Attributes are optional.
break;
}
}
Function *OpenMPIRBuilder::getOrCreateRuntimeFunction(RuntimeFunction FnID) {
Function *Fn = nullptr;
// Try to find the declation in the module first.
switch (FnID) {
#define OMP_RTL(Enum, Str, IsVarArg, ReturnType, ...) \
case Enum: \
Fn = M.getFunction(Str); \
break;
#include "llvm/Frontend/OpenMP/OMPKinds.def"
}
if (!Fn) {
// Create a new declaration if we need one.
switch (FnID) {
#define OMP_RTL(Enum, Str, IsVarArg, ReturnType, ...) \
case Enum: \
Fn = Function::Create(FunctionType::get(ReturnType, \
ArrayRef<Type *>{__VA_ARGS__}, \
IsVarArg), \
GlobalValue::ExternalLinkage, Str, M); \
break;
#include "llvm/Frontend/OpenMP/OMPKinds.def"
}
addAttributes(FnID, *Fn);
}
assert(Fn && "Failed to create OpenMP runtime function");
return Fn;
}
void OpenMPIRBuilder::initialize() { initializeTypes(M); }
void OpenMPIRBuilder::finalize() {
for (OutlineInfo &OI : OutlineInfos) {
assert(!OI.Blocks.empty() &&
"Outlined regions should have at least a single block!");
BasicBlock *RegEntryBB = OI.Blocks.front();
Function *OuterFn = RegEntryBB->getParent();
CodeExtractorAnalysisCache CEAC(*OuterFn);
CodeExtractor Extractor(OI.Blocks, /* DominatorTree */ nullptr,
/* AggregateArgs */ false,
/* BlockFrequencyInfo */ nullptr,
/* BranchProbabilityInfo */ nullptr,
/* AssumptionCache */ nullptr,
/* AllowVarArgs */ true,
/* AllowAlloca */ true,
/* Suffix */ ".omp_par");
LLVM_DEBUG(dbgs() << "Before outlining: " << *OuterFn << "\n");
assert(Extractor.isEligible() &&
"Expected OpenMP outlining to be possible!");
Function *OutlinedFn = Extractor.extractCodeRegion(CEAC);
LLVM_DEBUG(dbgs() << "After outlining: " << *OuterFn << "\n");
LLVM_DEBUG(dbgs() << " Outlined function: " << *OutlinedFn << "\n");
assert(OutlinedFn->getReturnType()->isVoidTy() &&
"OpenMP outlined functions should not return a value!");
// For compability with the clang CG we move the outlined function after the
// one with the parallel region.
OutlinedFn->removeFromParent();
M.getFunctionList().insertAfter(OuterFn->getIterator(), OutlinedFn);
// Remove the artificial entry introduced by the extractor right away, we
// made our own entry block after all.
{
BasicBlock &ArtificialEntry = OutlinedFn->getEntryBlock();
assert(ArtificialEntry.getUniqueSuccessor() == RegEntryBB);
assert(RegEntryBB->getUniquePredecessor() == &ArtificialEntry);
RegEntryBB->moveBefore(&ArtificialEntry);
ArtificialEntry.eraseFromParent();
}
assert(&OutlinedFn->getEntryBlock() == RegEntryBB);
assert(OutlinedFn && OutlinedFn->getNumUses() == 1);
// Run a user callback, e.g. to add attributes.
if (OI.PostOutlineCB)
OI.PostOutlineCB(*OutlinedFn);
}
// Allow finalize to be called multiple times.
OutlineInfos.clear();
}
Value *OpenMPIRBuilder::getOrCreateIdent(Constant *SrcLocStr,
IdentFlag LocFlags) {
// Enable "C-mode".
LocFlags |= OMP_IDENT_FLAG_KMPC;
GlobalVariable *&DefaultIdent = IdentMap[{SrcLocStr, uint64_t(LocFlags)}];
if (!DefaultIdent) {
Constant *I32Null = ConstantInt::getNullValue(Int32);
Constant *IdentData[] = {I32Null,
ConstantInt::get(Int32, uint64_t(LocFlags)),
I32Null, I32Null, SrcLocStr};
Constant *Initializer = ConstantStruct::get(
cast<StructType>(IdentPtr->getPointerElementType()), IdentData);
// Look for existing encoding of the location + flags, not needed but
// minimizes the difference to the existing solution while we transition.
for (GlobalVariable &GV : M.getGlobalList())
if (GV.getType() == IdentPtr && GV.hasInitializer())
if (GV.getInitializer() == Initializer)
return DefaultIdent = &GV;
DefaultIdent = new GlobalVariable(M, IdentPtr->getPointerElementType(),
/* isConstant = */ false,
GlobalValue::PrivateLinkage, Initializer);
DefaultIdent->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
DefaultIdent->setAlignment(Align(8));
}
return DefaultIdent;
}
Constant *OpenMPIRBuilder::getOrCreateSrcLocStr(StringRef LocStr) {
Constant *&SrcLocStr = SrcLocStrMap[LocStr];
if (!SrcLocStr) {
Constant *Initializer =
ConstantDataArray::getString(M.getContext(), LocStr);
// Look for existing encoding of the location, not needed but minimizes the
// difference to the existing solution while we transition.
for (GlobalVariable &GV : M.getGlobalList())
if (GV.isConstant() && GV.hasInitializer() &&
GV.getInitializer() == Initializer)
return SrcLocStr = ConstantExpr::getPointerCast(&GV, Int8Ptr);
SrcLocStr = Builder.CreateGlobalStringPtr(LocStr);
}
return SrcLocStr;
}
Constant *OpenMPIRBuilder::getOrCreateDefaultSrcLocStr() {
return getOrCreateSrcLocStr(";unknown;unknown;0;0;;");
}
Constant *
OpenMPIRBuilder::getOrCreateSrcLocStr(const LocationDescription &Loc) {
DILocation *DIL = Loc.DL.get();
if (!DIL)
return getOrCreateDefaultSrcLocStr();
StringRef Filename =
!DIL->getFilename().empty() ? DIL->getFilename() : M.getName();
StringRef Function = DIL->getScope()->getSubprogram()->getName();
Function =
!Function.empty() ? Function : Loc.IP.getBlock()->getParent()->getName();
std::string LineStr = std::to_string(DIL->getLine());
std::string ColumnStr = std::to_string(DIL->getColumn());
std::stringstream SrcLocStr;
SrcLocStr << ";" << Filename.data() << ";" << Function.data() << ";"
<< LineStr << ";" << ColumnStr << ";;";
return getOrCreateSrcLocStr(SrcLocStr.str());
}
Value *OpenMPIRBuilder::getOrCreateThreadID(Value *Ident) {
return Builder.CreateCall(
getOrCreateRuntimeFunction(OMPRTL___kmpc_global_thread_num), Ident,
"omp_global_thread_num");
}
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::CreateBarrier(const LocationDescription &Loc, Directive DK,
bool ForceSimpleCall, bool CheckCancelFlag) {
if (!updateToLocation(Loc))
return Loc.IP;
return emitBarrierImpl(Loc, DK, ForceSimpleCall, CheckCancelFlag);
}
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::emitBarrierImpl(const LocationDescription &Loc, Directive Kind,
bool ForceSimpleCall, bool CheckCancelFlag) {
// Build call __kmpc_cancel_barrier(loc, thread_id) or
// __kmpc_barrier(loc, thread_id);
IdentFlag BarrierLocFlags;
switch (Kind) {
case OMPD_for:
BarrierLocFlags = OMP_IDENT_FLAG_BARRIER_IMPL_FOR;
break;
case OMPD_sections:
BarrierLocFlags = OMP_IDENT_FLAG_BARRIER_IMPL_SECTIONS;
break;
case OMPD_single:
BarrierLocFlags = OMP_IDENT_FLAG_BARRIER_IMPL_SINGLE;
break;
case OMPD_barrier:
BarrierLocFlags = OMP_IDENT_FLAG_BARRIER_EXPL;
break;
default:
BarrierLocFlags = OMP_IDENT_FLAG_BARRIER_IMPL;
break;
}
Constant *SrcLocStr = getOrCreateSrcLocStr(Loc);
Value *Args[] = {getOrCreateIdent(SrcLocStr, BarrierLocFlags),
getOrCreateThreadID(getOrCreateIdent(SrcLocStr))};
// If we are in a cancellable parallel region, barriers are cancellation
// points.
// TODO: Check why we would force simple calls or to ignore the cancel flag.
bool UseCancelBarrier =
!ForceSimpleCall && isLastFinalizationInfoCancellable(OMPD_parallel);
Value *Result = Builder.CreateCall(
getOrCreateRuntimeFunction(UseCancelBarrier ? OMPRTL___kmpc_cancel_barrier
: OMPRTL___kmpc_barrier),
Args);
if (UseCancelBarrier && CheckCancelFlag)
emitCancelationCheckImpl(Result, OMPD_parallel);
return Builder.saveIP();
}
OpenMPIRBuilder::InsertPointTy
OpenMPIRBuilder::CreateCancel(const LocationDescription &Loc,
Value *IfCondition,
omp::Directive CanceledDirective) {
if (!updateToLocation(Loc))
return Loc.IP;
// LLVM utilities like blocks with terminators.
auto *UI = Builder.CreateUnreachable();
Instruction *ThenTI = UI, *ElseTI = nullptr;
if (IfCondition)
SplitBlockAndInsertIfThenElse(IfCondition, UI, &ThenTI, &ElseTI);
Builder.SetInsertPoint(ThenTI);
Value *CancelKind = nullptr;
switch (CanceledDirective) {
#define OMP_CANCEL_KIND(Enum, Str, DirectiveEnum, Value) \
case DirectiveEnum: \
CancelKind = Builder.getInt32(Value); \
break;
#include "llvm/Frontend/OpenMP/OMPKinds.def"
default:
llvm_unreachable("Unknown cancel kind!");
}
Constant *SrcLocStr = getOrCreateSrcLocStr(Loc);
Value *Ident = getOrCreateIdent(SrcLocStr);
Value *Args[] = {Ident, getOrCreateThreadID(Ident), CancelKind};
Value *Result = Builder.CreateCall(
getOrCreateRuntimeFunction(OMPRTL___kmpc_cancel), Args);
// The actual cancel logic is shared with others, e.g., cancel_barriers.
emitCancelationCheckImpl(Result, CanceledDirective);
// Update the insertion point and remove the terminator we introduced.
Builder.SetInsertPoint(UI->getParent());
UI->eraseFromParent();
return Builder.saveIP();
}
void OpenMPIRBuilder::emitCancelationCheckImpl(
Value *CancelFlag, omp::Directive CanceledDirective) {
assert(isLastFinalizationInfoCancellable(CanceledDirective) &&
"Unexpected cancellation!");
// For a cancel barrier we create two new blocks.
BasicBlock *BB = Builder.GetInsertBlock();
BasicBlock *NonCancellationBlock;
if (Builder.GetInsertPoint() == BB->end()) {
// TODO: This branch will not be needed once we moved to the
// OpenMPIRBuilder codegen completely.
NonCancellationBlock = BasicBlock::Create(
BB->getContext(), BB->getName() + ".cont", BB->getParent());
} else {
NonCancellationBlock = SplitBlock(BB, &*Builder.GetInsertPoint());
BB->getTerminator()->eraseFromParent();
Builder.SetInsertPoint(BB);
}
BasicBlock *CancellationBlock = BasicBlock::Create(
BB->getContext(), BB->getName() + ".cncl", BB->getParent());
// Jump to them based on the return value.
Value *Cmp = Builder.CreateIsNull(CancelFlag);
Builder.CreateCondBr(Cmp, NonCancellationBlock, CancellationBlock,
/* TODO weight */ nullptr, nullptr);
// From the cancellation block we finalize all variables and go to the
// post finalization block that is known to the FiniCB callback.
Builder.SetInsertPoint(CancellationBlock);
auto &FI = FinalizationStack.back();
FI.FiniCB(Builder.saveIP());
// The continuation block is where code generation continues.
Builder.SetInsertPoint(NonCancellationBlock, NonCancellationBlock->begin());
}
IRBuilder<>::InsertPoint OpenMPIRBuilder::CreateParallel(
const LocationDescription &Loc, BodyGenCallbackTy BodyGenCB,
PrivatizeCallbackTy PrivCB, FinalizeCallbackTy FiniCB, Value *IfCondition,
Value *NumThreads, omp::ProcBindKind ProcBind, bool IsCancellable) {
if (!updateToLocation(Loc))
return Loc.IP;
Constant *SrcLocStr = getOrCreateSrcLocStr(Loc);
Value *Ident = getOrCreateIdent(SrcLocStr);
Value *ThreadID = getOrCreateThreadID(Ident);
if (NumThreads) {
// Build call __kmpc_push_num_threads(&Ident, global_tid, num_threads)
Value *Args[] = {
Ident, ThreadID,
Builder.CreateIntCast(NumThreads, Int32, /*isSigned*/ false)};
Builder.CreateCall(
getOrCreateRuntimeFunction(OMPRTL___kmpc_push_num_threads), Args);
}
if (ProcBind != OMP_PROC_BIND_default) {
// Build call __kmpc_push_proc_bind(&Ident, global_tid, proc_bind)
Value *Args[] = {
Ident, ThreadID,
ConstantInt::get(Int32, unsigned(ProcBind), /*isSigned=*/true)};
Builder.CreateCall(getOrCreateRuntimeFunction(OMPRTL___kmpc_push_proc_bind),
Args);
}
BasicBlock *InsertBB = Builder.GetInsertBlock();
Function *OuterFn = InsertBB->getParent();
// Vector to remember instructions we used only during the modeling but which
// we want to delete at the end.
SmallVector<Instruction *, 4> ToBeDeleted;
Builder.SetInsertPoint(OuterFn->getEntryBlock().getFirstNonPHI());
AllocaInst *TIDAddr = Builder.CreateAlloca(Int32, nullptr, "tid.addr");
AllocaInst *ZeroAddr = Builder.CreateAlloca(Int32, nullptr, "zero.addr");
// If there is an if condition we actually use the TIDAddr and ZeroAddr in the
// program, otherwise we only need them for modeling purposes to get the
// associated arguments in the outlined function. In the former case,
// initialize the allocas properly, in the latter case, delete them later.
if (IfCondition) {
Builder.CreateStore(Constant::getNullValue(Int32), TIDAddr);
Builder.CreateStore(Constant::getNullValue(Int32), ZeroAddr);
} else {
ToBeDeleted.push_back(TIDAddr);
ToBeDeleted.push_back(ZeroAddr);
}
// Create an artificial insertion point that will also ensure the blocks we
// are about to split are not degenerated.
auto *UI = new UnreachableInst(Builder.getContext(), InsertBB);
Instruction *ThenTI = UI, *ElseTI = nullptr;
if (IfCondition)
SplitBlockAndInsertIfThenElse(IfCondition, UI, &ThenTI, &ElseTI);
BasicBlock *ThenBB = ThenTI->getParent();
BasicBlock *PRegEntryBB = ThenBB->splitBasicBlock(ThenTI, "omp.par.entry");
BasicBlock *PRegBodyBB =
PRegEntryBB->splitBasicBlock(ThenTI, "omp.par.region");
BasicBlock *PRegPreFiniBB =
PRegBodyBB->splitBasicBlock(ThenTI, "omp.par.pre_finalize");
BasicBlock *PRegExitBB =
PRegPreFiniBB->splitBasicBlock(ThenTI, "omp.par.exit");
auto FiniCBWrapper = [&](InsertPointTy IP) {
// Hide "open-ended" blocks from the given FiniCB by setting the right jump
// target to the region exit block.
if (IP.getBlock()->end() == IP.getPoint()) {
IRBuilder<>::InsertPointGuard IPG(Builder);
Builder.restoreIP(IP);
Instruction *I = Builder.CreateBr(PRegExitBB);
IP = InsertPointTy(I->getParent(), I->getIterator());
}
assert(IP.getBlock()->getTerminator()->getNumSuccessors() == 1 &&
IP.getBlock()->getTerminator()->getSuccessor(0) == PRegExitBB &&
"Unexpected insertion point for finalization call!");
return FiniCB(IP);
};
FinalizationStack.push_back({FiniCBWrapper, OMPD_parallel, IsCancellable});
// Generate the privatization allocas in the block that will become the entry
// of the outlined function.
InsertPointTy AllocaIP(PRegEntryBB,
PRegEntryBB->getTerminator()->getIterator());
Builder.restoreIP(AllocaIP);
AllocaInst *PrivTIDAddr =
Builder.CreateAlloca(Int32, nullptr, "tid.addr.local");
Instruction *PrivTID = Builder.CreateLoad(PrivTIDAddr, "tid");
// Add some fake uses for OpenMP provided arguments.
ToBeDeleted.push_back(Builder.CreateLoad(TIDAddr, "tid.addr.use"));
ToBeDeleted.push_back(Builder.CreateLoad(ZeroAddr, "zero.addr.use"));
// ThenBB
// |
// V
// PRegionEntryBB <- Privatization allocas are placed here.
// |
// V
// PRegionBodyBB <- BodeGen is invoked here.
// |
// V
// PRegPreFiniBB <- The block we will start finalization from.
// |
// V
// PRegionExitBB <- A common exit to simplify block collection.
//
LLVM_DEBUG(dbgs() << "Before body codegen: " << *OuterFn << "\n");
// Let the caller create the body.
assert(BodyGenCB && "Expected body generation callback!");
InsertPointTy CodeGenIP(PRegBodyBB, PRegBodyBB->begin());
BodyGenCB(AllocaIP, CodeGenIP, *PRegPreFiniBB);
LLVM_DEBUG(dbgs() << "After body codegen: " << *OuterFn << "\n");
FunctionCallee RTLFn = getOrCreateRuntimeFunction(OMPRTL___kmpc_fork_call);
if (auto *F = dyn_cast<llvm::Function>(RTLFn.getCallee())) {
if (!F->hasMetadata(llvm::LLVMContext::MD_callback)) {
llvm::LLVMContext &Ctx = F->getContext();
MDBuilder MDB(Ctx);
// Annotate the callback behavior of the __kmpc_fork_call:
// - The callback callee is argument number 2 (microtask).
// - The first two arguments of the callback callee are unknown (-1).
// - All variadic arguments to the __kmpc_fork_call are passed to the
// callback callee.
F->addMetadata(
llvm::LLVMContext::MD_callback,
*llvm::MDNode::get(
Ctx, {MDB.createCallbackEncoding(2, {-1, -1},
/* VarArgsArePassed */ true)}));
}
}
OutlineInfo OI;
OI.PostOutlineCB = [=](Function &OutlinedFn) {
// Add some known attributes.
OutlinedFn.addParamAttr(0, Attribute::NoAlias);
OutlinedFn.addParamAttr(1, Attribute::NoAlias);
OutlinedFn.addFnAttr(Attribute::NoUnwind);
OutlinedFn.addFnAttr(Attribute::NoRecurse);
assert(OutlinedFn.arg_size() >= 2 &&
"Expected at least tid and bounded tid as arguments");
unsigned NumCapturedVars =
OutlinedFn.arg_size() - /* tid & bounded tid */ 2;
CallInst *CI = cast<CallInst>(OutlinedFn.user_back());
CI->getParent()->setName("omp_parallel");
Builder.SetInsertPoint(CI);
// Build call __kmpc_fork_call(Ident, n, microtask, var1, .., varn);
Value *ForkCallArgs[] = {
Ident, Builder.getInt32(NumCapturedVars),
Builder.CreateBitCast(&OutlinedFn, ParallelTaskPtr)};
SmallVector<Value *, 16> RealArgs;
RealArgs.append(std::begin(ForkCallArgs), std::end(ForkCallArgs));
RealArgs.append(CI->arg_begin() + /* tid & bound tid */ 2, CI->arg_end());
Builder.CreateCall(RTLFn, RealArgs);
LLVM_DEBUG(dbgs() << "With fork_call placed: "
<< *Builder.GetInsertBlock()->getParent() << "\n");
InsertPointTy ExitIP(PRegExitBB, PRegExitBB->end());
// Initialize the local TID stack location with the argument value.
Builder.SetInsertPoint(PrivTID);
Function::arg_iterator OutlinedAI = OutlinedFn.arg_begin();
Builder.CreateStore(Builder.CreateLoad(OutlinedAI), PrivTIDAddr);
// If no "if" clause was present we do not need the call created during
// outlining, otherwise we reuse it in the serialized parallel region.
if (!ElseTI) {
CI->eraseFromParent();
} else {
// If an "if" clause was present we are now generating the serialized
// version into the "else" branch.
Builder.SetInsertPoint(ElseTI);
// Build calls __kmpc_serialized_parallel(&Ident, GTid);
Value *SerializedParallelCallArgs[] = {Ident, ThreadID};
Builder.CreateCall(
getOrCreateRuntimeFunction(OMPRTL___kmpc_serialized_parallel),
SerializedParallelCallArgs);
// OutlinedFn(&GTid, &zero, CapturedStruct);
CI->removeFromParent();
Builder.Insert(CI);
// __kmpc_end_serialized_parallel(&Ident, GTid);
Value *EndArgs[] = {Ident, ThreadID};
Builder.CreateCall(
getOrCreateRuntimeFunction(OMPRTL___kmpc_end_serialized_parallel),
EndArgs);
LLVM_DEBUG(dbgs() << "With serialized parallel region: "
<< *Builder.GetInsertBlock()->getParent() << "\n");
}
for (Instruction *I : ToBeDeleted)
I->eraseFromParent();
};
// Adjust the finalization stack, verify the adjustment, and call the
// finalize function a last time to finalize values between the pre-fini
// block and the exit block if we left the parallel "the normal way".
auto FiniInfo = FinalizationStack.pop_back_val();
(void)FiniInfo;
assert(FiniInfo.DK == OMPD_parallel &&
"Unexpected finalization stack state!");
Instruction *PRegPreFiniTI = PRegPreFiniBB->getTerminator();
assert(PRegPreFiniTI->getNumSuccessors() == 1 &&
PRegPreFiniTI->getSuccessor(0) == PRegExitBB &&
"Unexpected CFG structure!");
InsertPointTy PreFiniIP(PRegPreFiniBB, PRegPreFiniTI->getIterator());
FiniCB(PreFiniIP);
SmallPtrSet<BasicBlock *, 32> ParallelRegionBlockSet;
SmallVector<BasicBlock *, 32> Worklist;
ParallelRegionBlockSet.insert(PRegEntryBB);
ParallelRegionBlockSet.insert(PRegExitBB);
// Collect all blocks in-between PRegEntryBB and PRegExitBB.
Worklist.push_back(PRegEntryBB);
while (!Worklist.empty()) {
BasicBlock *BB = Worklist.pop_back_val();
OI.Blocks.push_back(BB);
for (BasicBlock *SuccBB : successors(BB))
if (ParallelRegionBlockSet.insert(SuccBB).second)
Worklist.push_back(SuccBB);
}
// Ensure a single exit node for the outlined region by creating one.
// We might have multiple incoming edges to the exit now due to finalizations,
// e.g., cancel calls that cause the control flow to leave the region.
BasicBlock *PRegOutlinedExitBB = PRegExitBB;
PRegExitBB = SplitBlock(PRegExitBB, &*PRegExitBB->getFirstInsertionPt());
PRegOutlinedExitBB->setName("omp.par.outlined.exit");
OI.Blocks.push_back(PRegOutlinedExitBB);
CodeExtractorAnalysisCache CEAC(*OuterFn);
CodeExtractor Extractor(OI.Blocks, /* DominatorTree */ nullptr,
/* AggregateArgs */ false,
/* BlockFrequencyInfo */ nullptr,
/* BranchProbabilityInfo */ nullptr,
/* AssumptionCache */ nullptr,
/* AllowVarArgs */ true,
/* AllowAlloca */ true,
/* Suffix */ ".omp_par");
// Find inputs to, outputs from the code region.
BasicBlock *CommonExit = nullptr;
SetVector<Value *> Inputs, Outputs, SinkingCands, HoistingCands;
Extractor.findAllocas(CEAC, SinkingCands, HoistingCands, CommonExit);
Extractor.findInputsOutputs(Inputs, Outputs, SinkingCands);
LLVM_DEBUG(dbgs() << "Before privatization: " << *OuterFn << "\n");
FunctionCallee TIDRTLFn =
getOrCreateRuntimeFunction(OMPRTL___kmpc_global_thread_num);
auto PrivHelper = [&](Value &V) {
if (&V == TIDAddr || &V == ZeroAddr)
return;
SmallVector<Use *, 8> Uses;
for (Use &U : V.uses())
if (auto *UserI = dyn_cast<Instruction>(U.getUser()))
if (ParallelRegionBlockSet.count(UserI->getParent()))
Uses.push_back(&U);
Value *ReplacementValue = nullptr;
CallInst *CI = dyn_cast<CallInst>(&V);
if (CI && CI->getCalledFunction() == TIDRTLFn.getCallee()) {
ReplacementValue = PrivTID;
} else {
Builder.restoreIP(
PrivCB(AllocaIP, Builder.saveIP(), V, ReplacementValue));
assert(ReplacementValue &&
"Expected copy/create callback to set replacement value!");
if (ReplacementValue == &V)
return;
}
for (Use *UPtr : Uses)
UPtr->set(ReplacementValue);
};
for (Value *Input : Inputs) {
LLVM_DEBUG(dbgs() << "Captured input: " << *Input << "\n");
PrivHelper(*Input);
}
assert(Outputs.empty() &&
"OpenMP outlining should not produce live-out values!");
LLVM_DEBUG(dbgs() << "After privatization: " << *OuterFn << "\n");
LLVM_DEBUG({
for (auto *BB : OI.Blocks)
dbgs() << " PBR: " << BB->getName() << "\n";
});
// Register the outlined info.
addOutlineInfo(std::move(OI));
InsertPointTy AfterIP(UI->getParent(), UI->getParent()->end());
UI->eraseFromParent();
return AfterIP;
}
void OpenMPIRBuilder::emitFlush(const LocationDescription &Loc)
{
// Build call void __kmpc_flush(ident_t *loc)
Constant *SrcLocStr = getOrCreateSrcLocStr(Loc);
Value *Args[] = {getOrCreateIdent(SrcLocStr)};
Builder.CreateCall(getOrCreateRuntimeFunction(OMPRTL___kmpc_flush), Args);
}
void OpenMPIRBuilder::CreateFlush(const LocationDescription &Loc)
{
if (!updateToLocation(Loc))
return;
emitFlush(Loc);
}
void OpenMPIRBuilder::emitTaskwaitImpl(const LocationDescription &Loc) {
// Build call kmp_int32 __kmpc_omp_taskwait(ident_t *loc, kmp_int32
// global_tid);
Constant *SrcLocStr = getOrCreateSrcLocStr(Loc);
Value *Ident = getOrCreateIdent(SrcLocStr);
Value *Args[] = {Ident, getOrCreateThreadID(Ident)};
// Ignore return result until untied tasks are supported.
Builder.CreateCall(getOrCreateRuntimeFunction(OMPRTL___kmpc_omp_taskwait),
Args);
}
void OpenMPIRBuilder::CreateTaskwait(const LocationDescription &Loc) {
if (!updateToLocation(Loc))
return;
emitTaskwaitImpl(Loc);
}
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