//===-- IPO/OpenMPOpt.cpp - Collection of OpenMP specific optimizations ---===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// OpenMP specific optimizations:
//
// - Deduplication of runtime calls, e.g., omp_get_thread_num.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/IPO/OpenMPOpt.h"
#include "llvm/ADT/EnumeratedArray.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Analysis/CallGraphSCCPass.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/Frontend/OpenMP/OMPConstants.h"
#include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
#include "llvm/InitializePasses.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/IPO/Attributor.h"
#include "llvm/Transforms/Utils/CallGraphUpdater.h"
using namespace llvm;
using namespace omp;
#define DEBUG_TYPE "openmp-opt"
static cl::opt<bool> DisableOpenMPOptimizations(
"openmp-opt-disable", cl::ZeroOrMore,
cl::desc("Disable OpenMP specific optimizations."), cl::Hidden,
cl::init(false));
static cl::opt<bool> PrintICVValues("openmp-print-icv-values", cl::init(false),
cl::Hidden);
static cl::opt<bool> PrintOpenMPKernels("openmp-print-gpu-kernels",
cl::init(false), cl::Hidden);
STATISTIC(NumOpenMPRuntimeCallsDeduplicated,
"Number of OpenMP runtime calls deduplicated");
STATISTIC(NumOpenMPParallelRegionsDeleted,
"Number of OpenMP parallel regions deleted");
STATISTIC(NumOpenMPRuntimeFunctionsIdentified,
"Number of OpenMP runtime functions identified");
STATISTIC(NumOpenMPRuntimeFunctionUsesIdentified,
"Number of OpenMP runtime function uses identified");
STATISTIC(NumOpenMPTargetRegionKernels,
"Number of OpenMP target region entry points (=kernels) identified");
STATISTIC(
NumOpenMPParallelRegionsReplacedInGPUStateMachine,
"Number of OpenMP parallel regions replaced with ID in GPU state machines");
#if !defined(NDEBUG)
static constexpr auto TAG = "[" DEBUG_TYPE "]";
#endif
/// Apply \p CB to all uses of \p F. If \p LookThroughConstantExprUses is
/// true, constant expression users are not given to \p CB but their uses are
/// traversed transitively.
template <typename CBTy>
static void foreachUse(Function &F, CBTy CB,
bool LookThroughConstantExprUses = true) {
SmallVector<Use *, 8> Worklist(make_pointer_range(F.uses()));
for (unsigned idx = 0; idx < Worklist.size(); ++idx) {
Use &U = *Worklist[idx];
// Allow use in constant bitcasts and simply look through them.
if (LookThroughConstantExprUses && isa<ConstantExpr>(U.getUser())) {
for (Use &CEU : cast<ConstantExpr>(U.getUser())->uses())
Worklist.push_back(&CEU);
continue;
}
CB(U);
}
}
/// Helper struct to store tracked ICV values at specif instructions.
struct ICVValue {
Instruction *Inst;
Value *TrackedValue;
ICVValue(Instruction *I, Value *Val) : Inst(I), TrackedValue(Val) {}
};
namespace llvm {
// Provide DenseMapInfo for ICVValue
template <> struct DenseMapInfo<ICVValue> {
using InstInfo = DenseMapInfo<Instruction *>;
using ValueInfo = DenseMapInfo<Value *>;
static inline ICVValue getEmptyKey() {
return ICVValue(InstInfo::getEmptyKey(), ValueInfo::getEmptyKey());
};
static inline ICVValue getTombstoneKey() {
return ICVValue(InstInfo::getTombstoneKey(), ValueInfo::getTombstoneKey());
};
static unsigned getHashValue(const ICVValue &ICVVal) {
return detail::combineHashValue(
InstInfo::getHashValue(ICVVal.Inst),
ValueInfo::getHashValue(ICVVal.TrackedValue));
}
static bool isEqual(const ICVValue &LHS, const ICVValue &RHS) {
return InstInfo::isEqual(LHS.Inst, RHS.Inst) &&
ValueInfo::isEqual(LHS.TrackedValue, RHS.TrackedValue);
}
};
} // end namespace llvm
namespace {
struct AAICVTracker;
/// OpenMP specific information. For now, stores RFIs and ICVs also needed for
/// Attributor runs.
struct OMPInformationCache : public InformationCache {
OMPInformationCache(Module &M, AnalysisGetter &AG,
BumpPtrAllocator &Allocator, SetVector<Function *> &CGSCC,
SmallPtrSetImpl<Kernel> &Kernels)
: InformationCache(M, AG, Allocator, &CGSCC), OMPBuilder(M),
Kernels(Kernels) {
initializeModuleSlice(CGSCC);
OMPBuilder.initialize();
initializeRuntimeFunctions();
initializeInternalControlVars();
}
/// Generic information that describes an internal control variable.
struct InternalControlVarInfo {
/// The kind, as described by InternalControlVar enum.
InternalControlVar Kind;
/// The name of the ICV.
StringRef Name;
/// Environment variable associated with this ICV.
StringRef EnvVarName;
/// Initial value kind.
ICVInitValue InitKind;
/// Initial value.
ConstantInt *InitValue;
/// Setter RTL function associated with this ICV.
RuntimeFunction Setter;
/// Getter RTL function associated with this ICV.
RuntimeFunction Getter;
/// RTL Function corresponding to the override clause of this ICV
RuntimeFunction Clause;
};
/// Generic information that describes a runtime function
struct RuntimeFunctionInfo {
/// The kind, as described by the RuntimeFunction enum.
RuntimeFunction Kind;
/// The name of the function.
StringRef Name;
/// Flag to indicate a variadic function.
bool IsVarArg;
/// The return type of the function.
Type *ReturnType;
/// The argument types of the function.
SmallVector<Type *, 8> ArgumentTypes;
/// The declaration if available.
Function *Declaration = nullptr;
/// Uses of this runtime function per function containing the use.
using UseVector = SmallVector<Use *, 16>;
/// Clear UsesMap for runtime function.
void clearUsesMap() { UsesMap.clear(); }
/// Boolean conversion that is true if the runtime function was found.
operator bool() const { return Declaration; }
/// Return the vector of uses in function \p F.
UseVector &getOrCreateUseVector(Function *F) {
std::shared_ptr<UseVector> &UV = UsesMap[F];
if (!UV)
UV = std::make_shared<UseVector>();
return *UV;
}
/// Return the vector of uses in function \p F or `nullptr` if there are
/// none.
const UseVector *getUseVector(Function &F) const {
auto I = UsesMap.find(&F);
if (I != UsesMap.end())
return I->second.get();
return nullptr;
}
/// Return how many functions contain uses of this runtime function.
size_t getNumFunctionsWithUses() const { return UsesMap.size(); }
/// Return the number of arguments (or the minimal number for variadic
/// functions).
size_t getNumArgs() const { return ArgumentTypes.size(); }
/// Run the callback \p CB on each use and forget the use if the result is
/// true. The callback will be fed the function in which the use was
/// encountered as second argument.
void foreachUse(SmallVectorImpl<Function *> &SCC,
function_ref<bool(Use &, Function &)> CB) {
for (Function *F : SCC)
foreachUse(CB, F);
}
/// Run the callback \p CB on each use within the function \p F and forget
/// the use if the result is true.
void foreachUse(function_ref<bool(Use &, Function &)> CB, Function *F) {
SmallVector<unsigned, 8> ToBeDeleted;
ToBeDeleted.clear();
unsigned Idx = 0;
UseVector &UV = getOrCreateUseVector(F);
for (Use *U : UV) {
if (CB(*U, *F))
ToBeDeleted.push_back(Idx);
++Idx;
}
// Remove the to-be-deleted indices in reverse order as prior
// modifications will not modify the smaller indices.
while (!ToBeDeleted.empty()) {
unsigned Idx = ToBeDeleted.pop_back_val();
UV[Idx] = UV.back();
UV.pop_back();
}
}
private:
/// Map from functions to all uses of this runtime function contained in
/// them.
DenseMap<Function *, std::shared_ptr<UseVector>> UsesMap;
};
/// Initialize the ModuleSlice member based on \p SCC. ModuleSlices contains
/// (a subset of) all functions that we can look at during this SCC traversal.
/// This includes functions (transitively) called from the SCC and the
/// (transitive) callers of SCC functions. We also can look at a function if
/// there is a "reference edge", i.a., if the function somehow uses (!=calls)
/// a function in the SCC or a caller of a function in the SCC.
void initializeModuleSlice(SetVector<Function *> &SCC) {
ModuleSlice.insert(SCC.begin(), SCC.end());
SmallPtrSet<Function *, 16> Seen;
SmallVector<Function *, 16> Worklist(SCC.begin(), SCC.end());
while (!Worklist.empty()) {
Function *F = Worklist.pop_back_val();
ModuleSlice.insert(F);
for (Instruction &I : instructions(*F))
if (auto *CB = dyn_cast<CallBase>(&I))
if (Function *Callee = CB->getCalledFunction())
if (Seen.insert(Callee).second)
Worklist.push_back(Callee);
}
Seen.clear();
Worklist.append(SCC.begin(), SCC.end());
while (!Worklist.empty()) {
Function *F = Worklist.pop_back_val();
ModuleSlice.insert(F);
// Traverse all transitive uses.
foreachUse(*F, [&](Use &U) {
if (auto *UsrI = dyn_cast<Instruction>(U.getUser()))
if (Seen.insert(UsrI->getFunction()).second)
Worklist.push_back(UsrI->getFunction());
});
}
}
/// The slice of the module we are allowed to look at.
SmallPtrSet<Function *, 8> ModuleSlice;
/// An OpenMP-IR-Builder instance
OpenMPIRBuilder OMPBuilder;
/// Map from runtime function kind to the runtime function description.
EnumeratedArray<RuntimeFunctionInfo, RuntimeFunction,
RuntimeFunction::OMPRTL___last>
RFIs;
/// Map from ICV kind to the ICV description.
EnumeratedArray<InternalControlVarInfo, InternalControlVar,
InternalControlVar::ICV___last>
ICVs;
/// Helper to initialize all internal control variable information for those
/// defined in OMPKinds.def.
void initializeInternalControlVars() {
#define ICV_RT_SET(_Name, RTL) \
{ \
auto &ICV = ICVs[_Name]; \
ICV.Setter = RTL; \
}
#define ICV_RT_GET(Name, RTL) \
{ \
auto &ICV = ICVs[Name]; \
ICV.Getter = RTL; \
}
#define ICV_DATA_ENV(Enum, _Name, _EnvVarName, Init) \
{ \
auto &ICV = ICVs[Enum]; \
ICV.Name = _Name; \
ICV.Kind = Enum; \
ICV.InitKind = Init; \
ICV.EnvVarName = _EnvVarName; \
switch (ICV.InitKind) { \
case ICV_IMPLEMENTATION_DEFINED: \
ICV.InitValue = nullptr; \
break; \
case ICV_ZERO: \
ICV.InitValue = ConstantInt::get( \
Type::getInt32Ty(OMPBuilder.Int32->getContext()), 0); \
break; \
case ICV_FALSE: \
ICV.InitValue = ConstantInt::getFalse(OMPBuilder.Int1->getContext()); \
break; \
case ICV_LAST: \
break; \
} \
}
#include "llvm/Frontend/OpenMP/OMPKinds.def"
}
/// Returns true if the function declaration \p F matches the runtime
/// function types, that is, return type \p RTFRetType, and argument types
/// \p RTFArgTypes.
static bool declMatchesRTFTypes(Function *F, Type *RTFRetType,
SmallVector<Type *, 8> &RTFArgTypes) {
// TODO: We should output information to the user (under debug output
// and via remarks).
if (!F)
return false;
if (F->getReturnType() != RTFRetType)
return false;
if (F->arg_size() != RTFArgTypes.size())
return false;
auto RTFTyIt = RTFArgTypes.begin();
for (Argument &Arg : F->args()) {
if (Arg.getType() != *RTFTyIt)
return false;
++RTFTyIt;
}
return true;
}
// Helper to collect all uses of the declaration in the UsesMap.
unsigned collectUses(RuntimeFunctionInfo &RFI, bool CollectStats = true) {
unsigned NumUses = 0;
if (!RFI.Declaration)
return NumUses;
OMPBuilder.addAttributes(RFI.Kind, *RFI.Declaration);
if (CollectStats) {
NumOpenMPRuntimeFunctionsIdentified += 1;
NumOpenMPRuntimeFunctionUsesIdentified += RFI.Declaration->getNumUses();
}
// TODO: We directly convert uses into proper calls and unknown uses.
for (Use &U : RFI.Declaration->uses()) {
if (Instruction *UserI = dyn_cast<Instruction>(U.getUser())) {
if (ModuleSlice.count(UserI->getFunction())) {
RFI.getOrCreateUseVector(UserI->getFunction()).push_back(&U);
++NumUses;
}
} else {
RFI.getOrCreateUseVector(nullptr).push_back(&U);
++NumUses;
}
}
return NumUses;
}
// Helper function to recollect uses of all runtime functions.
void recollectUses() {
for (int Idx = 0; Idx < RFIs.size(); ++Idx) {
auto &RFI = RFIs[static_cast<RuntimeFunction>(Idx)];
RFI.clearUsesMap();
collectUses(RFI, /*CollectStats*/ false);
}
}
/// Helper to initialize all runtime function information for those defined
/// in OpenMPKinds.def.
void initializeRuntimeFunctions() {
Module &M = *((*ModuleSlice.begin())->getParent());
// Helper macros for handling __VA_ARGS__ in OMP_RTL
#define OMP_TYPE(VarName, ...) \
Type *VarName = OMPBuilder.VarName; \
(void)VarName;
#define OMP_ARRAY_TYPE(VarName, ...) \
ArrayType *VarName##Ty = OMPBuilder.VarName##Ty; \
(void)VarName##Ty; \
PointerType *VarName##PtrTy = OMPBuilder.VarName##PtrTy; \
(void)VarName##PtrTy;
#define OMP_FUNCTION_TYPE(VarName, ...) \
FunctionType *VarName = OMPBuilder.VarName; \
(void)VarName; \
PointerType *VarName##Ptr = OMPBuilder.VarName##Ptr; \
(void)VarName##Ptr;
#define OMP_STRUCT_TYPE(VarName, ...) \
StructType *VarName = OMPBuilder.VarName; \
(void)VarName; \
PointerType *VarName##Ptr = OMPBuilder.VarName##Ptr; \
(void)VarName##Ptr;
#define OMP_RTL(_Enum, _Name, _IsVarArg, _ReturnType, ...) \
{ \
SmallVector<Type *, 8> ArgsTypes({__VA_ARGS__}); \
Function *F = M.getFunction(_Name); \
if (declMatchesRTFTypes(F, OMPBuilder._ReturnType, ArgsTypes)) { \
auto &RFI = RFIs[_Enum]; \
RFI.Kind = _Enum; \
RFI.Name = _Name; \
RFI.IsVarArg = _IsVarArg; \
RFI.ReturnType = OMPBuilder._ReturnType; \
RFI.ArgumentTypes = std::move(ArgsTypes); \
RFI.Declaration = F; \
unsigned NumUses = collectUses(RFI); \
(void)NumUses; \
LLVM_DEBUG({ \
dbgs() << TAG << RFI.Name << (RFI.Declaration ? "" : " not") \
<< " found\n"; \
if (RFI.Declaration) \
dbgs() << TAG << "-> got " << NumUses << " uses in " \
<< RFI.getNumFunctionsWithUses() \
<< " different functions.\n"; \
}); \
} \
}
#include "llvm/Frontend/OpenMP/OMPKinds.def"
// TODO: We should attach the attributes defined in OMPKinds.def.
}
/// Collection of known kernels (\see Kernel) in the module.
SmallPtrSetImpl<Kernel> &Kernels;
};
struct OpenMPOpt {
using OptimizationRemarkGetter =
function_ref<OptimizationRemarkEmitter &(Function *)>;
OpenMPOpt(SmallVectorImpl<Function *> &SCC, CallGraphUpdater &CGUpdater,
OptimizationRemarkGetter OREGetter,
OMPInformationCache &OMPInfoCache, Attributor &A)
: M(*(*SCC.begin())->getParent()), SCC(SCC), CGUpdater(CGUpdater),
OREGetter(OREGetter), OMPInfoCache(OMPInfoCache), A(A) {}
/// Run all OpenMP optimizations on the underlying SCC/ModuleSlice.
bool run() {
if (SCC.empty())
return false;
bool Changed = false;
LLVM_DEBUG(dbgs() << TAG << "Run on SCC with " << SCC.size()
<< " functions in a slice with "
<< OMPInfoCache.ModuleSlice.size() << " functions\n");
if (PrintICVValues)
printICVs();
if (PrintOpenMPKernels)
printKernels();
Changed |= rewriteDeviceCodeStateMachine();
Changed |= runAttributor();
// Recollect uses, in case Attributor deleted any.
OMPInfoCache.recollectUses();
Changed |= deduplicateRuntimeCalls();
Changed |= deleteParallelRegions();
return Changed;
}
/// Print initial ICV values for testing.
/// FIXME: This should be done from the Attributor once it is added.
void printICVs() const {
InternalControlVar ICVs[] = {ICV_nthreads, ICV_active_levels, ICV_cancel};
for (Function *F : OMPInfoCache.ModuleSlice) {
for (auto ICV : ICVs) {
auto ICVInfo = OMPInfoCache.ICVs[ICV];
auto Remark = [&](OptimizationRemark OR) {
return OR << "OpenMP ICV " << ore::NV("OpenMPICV", ICVInfo.Name)
<< " Value: "
<< (ICVInfo.InitValue
? ICVInfo.InitValue->getValue().toString(10, true)
: "IMPLEMENTATION_DEFINED");
};
emitRemarkOnFunction(F, "OpenMPICVTracker", Remark);
}
}
}
/// Print OpenMP GPU kernels for testing.
void printKernels() const {
for (Function *F : SCC) {
if (!OMPInfoCache.Kernels.count(F))
continue;
auto Remark = [&](OptimizationRemark OR) {
return OR << "OpenMP GPU kernel "
<< ore::NV("OpenMPGPUKernel", F->getName()) << "\n";
};
emitRemarkOnFunction(F, "OpenMPGPU", Remark);
}
}
/// Return the call if \p U is a callee use in a regular call. If \p RFI is
/// given it has to be the callee or a nullptr is returned.
static CallInst *getCallIfRegularCall(
Use &U, OMPInformationCache::RuntimeFunctionInfo *RFI = nullptr) {
CallInst *CI = dyn_cast<CallInst>(U.getUser());
if (CI && CI->isCallee(&U) && !CI->hasOperandBundles() &&
(!RFI || CI->getCalledFunction() == RFI->Declaration))
return CI;
return nullptr;
}
/// Return the call if \p V is a regular call. If \p RFI is given it has to be
/// the callee or a nullptr is returned.
static CallInst *getCallIfRegularCall(
Value &V, OMPInformationCache::RuntimeFunctionInfo *RFI = nullptr) {
CallInst *CI = dyn_cast<CallInst>(&V);
if (CI && !CI->hasOperandBundles() &&
(!RFI || CI->getCalledFunction() == RFI->Declaration))
return CI;
return nullptr;
}
private:
/// Try to delete parallel regions if possible.
bool deleteParallelRegions() {
const unsigned CallbackCalleeOperand = 2;
OMPInformationCache::RuntimeFunctionInfo &RFI =
OMPInfoCache.RFIs[OMPRTL___kmpc_fork_call];
if (!RFI.Declaration)
return false;
bool Changed = false;
auto DeleteCallCB = [&](Use &U, Function &) {
CallInst *CI = getCallIfRegularCall(U);
if (!CI)
return false;
auto *Fn = dyn_cast<Function>(
CI->getArgOperand(CallbackCalleeOperand)->stripPointerCasts());
if (!Fn)
return false;
if (!Fn->onlyReadsMemory())
return false;
if (!Fn->hasFnAttribute(Attribute::WillReturn))
return false;
LLVM_DEBUG(dbgs() << TAG << "Delete read-only parallel region in "
<< CI->getCaller()->getName() << "\n");
auto Remark = [&](OptimizationRemark OR) {
return OR << "Parallel region in "
<< ore::NV("OpenMPParallelDelete", CI->getCaller()->getName())
<< " deleted";
};
emitRemark<OptimizationRemark>(CI, "OpenMPParallelRegionDeletion",
Remark);
CGUpdater.removeCallSite(*CI);
CI->eraseFromParent();
Changed = true;
++NumOpenMPParallelRegionsDeleted;
return true;
};
RFI.foreachUse(SCC, DeleteCallCB);
return Changed;
}
/// Try to eliminate runtime calls by reusing existing ones.
bool deduplicateRuntimeCalls() {
bool Changed = false;
RuntimeFunction DeduplicableRuntimeCallIDs[] = {
OMPRTL_omp_get_num_threads,
OMPRTL_omp_in_parallel,
OMPRTL_omp_get_cancellation,
OMPRTL_omp_get_thread_limit,
OMPRTL_omp_get_supported_active_levels,
OMPRTL_omp_get_level,
OMPRTL_omp_get_ancestor_thread_num,
OMPRTL_omp_get_team_size,
OMPRTL_omp_get_active_level,
OMPRTL_omp_in_final,
OMPRTL_omp_get_proc_bind,
OMPRTL_omp_get_num_places,
OMPRTL_omp_get_num_procs,
OMPRTL_omp_get_place_num,
OMPRTL_omp_get_partition_num_places,
OMPRTL_omp_get_partition_place_nums};
// Global-tid is handled separately.
SmallSetVector<Value *, 16> GTIdArgs;
collectGlobalThreadIdArguments(GTIdArgs);
LLVM_DEBUG(dbgs() << TAG << "Found " << GTIdArgs.size()
<< " global thread ID arguments\n");
for (Function *F : SCC) {
for (auto DeduplicableRuntimeCallID : DeduplicableRuntimeCallIDs)
deduplicateRuntimeCalls(*F,
OMPInfoCache.RFIs[DeduplicableRuntimeCallID]);
// __kmpc_global_thread_num is special as we can replace it with an
// argument in enough cases to make it worth trying.
Value *GTIdArg = nullptr;
for (Argument &Arg : F->args())
if (GTIdArgs.count(&Arg)) {
GTIdArg = &Arg;
break;
}
Changed |= deduplicateRuntimeCalls(
*F, OMPInfoCache.RFIs[OMPRTL___kmpc_global_thread_num], GTIdArg);
}
return Changed;
}
static Value *combinedIdentStruct(Value *CurrentIdent, Value *NextIdent,
bool GlobalOnly, bool &SingleChoice) {
if (CurrentIdent == NextIdent)
return CurrentIdent;
// TODO: Figure out how to actually combine multiple debug locations. For
// now we just keep an existing one if there is a single choice.
if (!GlobalOnly || isa<GlobalValue>(NextIdent)) {
SingleChoice = !CurrentIdent;
return NextIdent;
}
return nullptr;
}
/// Return an `struct ident_t*` value that represents the ones used in the
/// calls of \p RFI inside of \p F. If \p GlobalOnly is true, we will not
/// return a local `struct ident_t*`. For now, if we cannot find a suitable
/// return value we create one from scratch. We also do not yet combine
/// information, e.g., the source locations, see combinedIdentStruct.
Value *
getCombinedIdentFromCallUsesIn(OMPInformationCache::RuntimeFunctionInfo &RFI,
Function &F, bool GlobalOnly) {
bool SingleChoice = true;
Value *Ident = nullptr;
auto CombineIdentStruct = [&](Use &U, Function &Caller) {
CallInst *CI = getCallIfRegularCall(U, &RFI);
if (!CI || &F != &Caller)
return false;
Ident = combinedIdentStruct(Ident, CI->getArgOperand(0),
/* GlobalOnly */ true, SingleChoice);
return false;
};
RFI.foreachUse(SCC, CombineIdentStruct);
if (!Ident || !SingleChoice) {
// The IRBuilder uses the insertion block to get to the module, this is
// unfortunate but we work around it for now.
if (!OMPInfoCache.OMPBuilder.getInsertionPoint().getBlock())
OMPInfoCache.OMPBuilder.updateToLocation(OpenMPIRBuilder::InsertPointTy(
&F.getEntryBlock(), F.getEntryBlock().begin()));
// Create a fallback location if non was found.
// TODO: Use the debug locations of the calls instead.
Constant *Loc = OMPInfoCache.OMPBuilder.getOrCreateDefaultSrcLocStr();
Ident = OMPInfoCache.OMPBuilder.getOrCreateIdent(Loc);
}
return Ident;
}
/// Try to eliminate calls of \p RFI in \p F by reusing an existing one or
/// \p ReplVal if given.
bool deduplicateRuntimeCalls(Function &F,
OMPInformationCache::RuntimeFunctionInfo &RFI,
Value *ReplVal = nullptr) {
auto *UV = RFI.getUseVector(F);
if (!UV || UV->size() + (ReplVal != nullptr) < 2)
return false;
LLVM_DEBUG(
dbgs() << TAG << "Deduplicate " << UV->size() << " uses of " << RFI.Name
<< (ReplVal ? " with an existing value\n" : "\n") << "\n");
assert((!ReplVal || (isa<Argument>(ReplVal) &&
cast<Argument>(ReplVal)->getParent() == &F)) &&
"Unexpected replacement value!");
// TODO: Use dominance to find a good position instead.
auto CanBeMoved = [this](CallBase &CB) {
unsigned NumArgs = CB.getNumArgOperands();
if (NumArgs == 0)
return true;
if (CB.getArgOperand(0)->getType() != OMPInfoCache.OMPBuilder.IdentPtr)
return false;
for (unsigned u = 1; u < NumArgs; ++u)
if (isa<Instruction>(CB.getArgOperand(u)))
return false;
return true;
};
if (!ReplVal) {
for (Use *U : *UV)
if (CallInst *CI = getCallIfRegularCall(*U, &RFI)) {
if (!CanBeMoved(*CI))
continue;
auto Remark = [&](OptimizationRemark OR) {
auto newLoc = &*F.getEntryBlock().getFirstInsertionPt();
return OR << "OpenMP runtime call "
<< ore::NV("OpenMPOptRuntime", RFI.Name) << " moved to "
<< ore::NV("OpenMPRuntimeMoves", newLoc->getDebugLoc());
};
emitRemark<OptimizationRemark>(CI, "OpenMPRuntimeCodeMotion", Remark);
CI->moveBefore(&*F.getEntryBlock().getFirstInsertionPt());
ReplVal = CI;
break;
}
if (!ReplVal)
return false;
}
// If we use a call as a replacement value we need to make sure the ident is
// valid at the new location. For now we just pick a global one, either
// existing and used by one of the calls, or created from scratch.
if (CallBase *CI = dyn_cast<CallBase>(ReplVal)) {
if (CI->getNumArgOperands() > 0 &&
CI->getArgOperand(0)->getType() == OMPInfoCache.OMPBuilder.IdentPtr) {
Value *Ident = getCombinedIdentFromCallUsesIn(RFI, F,
/* GlobalOnly */ true);
CI->setArgOperand(0, Ident);
}
}
bool Changed = false;
auto ReplaceAndDeleteCB = [&](Use &U, Function &Caller) {
CallInst *CI = getCallIfRegularCall(U, &RFI);
if (!CI || CI == ReplVal || &F != &Caller)
return false;
assert(CI->getCaller() == &F && "Unexpected call!");
auto Remark = [&](OptimizationRemark OR) {
return OR << "OpenMP runtime call "
<< ore::NV("OpenMPOptRuntime", RFI.Name) << " deduplicated";
};
emitRemark<OptimizationRemark>(CI, "OpenMPRuntimeDeduplicated", Remark);
CGUpdater.removeCallSite(*CI);
CI->replaceAllUsesWith(ReplVal);
CI->eraseFromParent();
++NumOpenMPRuntimeCallsDeduplicated;
Changed = true;
return true;
};
RFI.foreachUse(SCC, ReplaceAndDeleteCB);
return Changed;
}
/// Collect arguments that represent the global thread id in \p GTIdArgs.
void collectGlobalThreadIdArguments(SmallSetVector<Value *, 16> >IdArgs) {
// TODO: Below we basically perform a fixpoint iteration with a pessimistic
// initialization. We could define an AbstractAttribute instead and
// run the Attributor here once it can be run as an SCC pass.
// Helper to check the argument \p ArgNo at all call sites of \p F for
// a GTId.
auto CallArgOpIsGTId = [&](Function &F, unsigned ArgNo, CallInst &RefCI) {
if (!F.hasLocalLinkage())
return false;
for (Use &U : F.uses()) {
if (CallInst *CI = getCallIfRegularCall(U)) {
Value *ArgOp = CI->getArgOperand(ArgNo);
if (CI == &RefCI || GTIdArgs.count(ArgOp) ||
getCallIfRegularCall(
*ArgOp, &OMPInfoCache.RFIs[OMPRTL___kmpc_global_thread_num]))
continue;
}
return false;
}
return true;
};
// Helper to identify uses of a GTId as GTId arguments.
auto AddUserArgs = [&](Value >Id) {
for (Use &U : GTId.uses())
if (CallInst *CI = dyn_cast<CallInst>(U.getUser()))
if (CI->isArgOperand(&U))
if (Function *Callee = CI->getCalledFunction())
if (CallArgOpIsGTId(*Callee, U.getOperandNo(), *CI))
GTIdArgs.insert(Callee->getArg(U.getOperandNo()));
};
// The argument users of __kmpc_global_thread_num calls are GTIds.
OMPInformationCache::RuntimeFunctionInfo &GlobThreadNumRFI =
OMPInfoCache.RFIs[OMPRTL___kmpc_global_thread_num];
GlobThreadNumRFI.foreachUse(SCC, [&](Use &U, Function &F) {
if (CallInst *CI = getCallIfRegularCall(U, &GlobThreadNumRFI))
AddUserArgs(*CI);
return false;
});
// Transitively search for more arguments by looking at the users of the
// ones we know already. During the search the GTIdArgs vector is extended
// so we cannot cache the size nor can we use a range based for.
for (unsigned u = 0; u < GTIdArgs.size(); ++u)
AddUserArgs(*GTIdArgs[u]);
}
/// Kernel (=GPU) optimizations and utility functions
///
///{{
/// Check if \p F is a kernel, hence entry point for target offloading.
bool isKernel(Function &F) { return OMPInfoCache.Kernels.count(&F); }
/// Cache to remember the unique kernel for a function.
DenseMap<Function *, Optional<Kernel>> UniqueKernelMap;
/// Find the unique kernel that will execute \p F, if any.
Kernel getUniqueKernelFor(Function &F);
/// Find the unique kernel that will execute \p I, if any.
Kernel getUniqueKernelFor(Instruction &I) {
return getUniqueKernelFor(*I.getFunction());
}
/// Rewrite the device (=GPU) code state machine create in non-SPMD mode in
/// the cases we can avoid taking the address of a function.
bool rewriteDeviceCodeStateMachine();
///
///}}
/// Emit a remark generically
///
/// This template function can be used to generically emit a remark. The
/// RemarkKind should be one of the following:
/// - OptimizationRemark to indicate a successful optimization attempt
/// - OptimizationRemarkMissed to report a failed optimization attempt
/// - OptimizationRemarkAnalysis to provide additional information about an
/// optimization attempt
///
/// The remark is built using a callback function provided by the caller that
/// takes a RemarkKind as input and returns a RemarkKind.
template <typename RemarkKind,
typename RemarkCallBack = function_ref<RemarkKind(RemarkKind &&)>>
void emitRemark(Instruction *Inst, StringRef RemarkName,
RemarkCallBack &&RemarkCB) const {
Function *F = Inst->getParent()->getParent();
auto &ORE = OREGetter(F);
ORE.emit(
[&]() { return RemarkCB(RemarkKind(DEBUG_TYPE, RemarkName, Inst)); });
}
/// Emit a remark on a function. Since only OptimizationRemark is supporting
/// this, it can't be made generic.
void
emitRemarkOnFunction(Function *F, StringRef RemarkName,
function_ref<OptimizationRemark(OptimizationRemark &&)>
&&RemarkCB) const {
auto &ORE = OREGetter(F);
ORE.emit([&]() {
return RemarkCB(OptimizationRemark(DEBUG_TYPE, RemarkName, F));
});
}
/// The underlying module.
Module &M;
/// The SCC we are operating on.
SmallVectorImpl<Function *> &SCC;
/// Callback to update the call graph, the first argument is a removed call,
/// the second an optional replacement call.
CallGraphUpdater &CGUpdater;
/// Callback to get an OptimizationRemarkEmitter from a Function *
OptimizationRemarkGetter OREGetter;
/// OpenMP-specific information cache. Also Used for Attributor runs.
OMPInformationCache &OMPInfoCache;
/// Attributor instance.
Attributor &A;
/// Helper function to run Attributor on SCC.
bool runAttributor() {
if (SCC.empty())
return false;
registerAAs();
ChangeStatus Changed = A.run();
LLVM_DEBUG(dbgs() << "[Attributor] Done with " << SCC.size()
<< " functions, result: " << Changed << ".\n");
return Changed == ChangeStatus::CHANGED;
}
/// Populate the Attributor with abstract attribute opportunities in the
/// function.
void registerAAs() {
for (Function *F : SCC) {
if (F->isDeclaration())
continue;
A.getOrCreateAAFor<AAICVTracker>(IRPosition::function(*F));
}
}
};
Kernel OpenMPOpt::getUniqueKernelFor(Function &F) {
if (!OMPInfoCache.ModuleSlice.count(&F))
return nullptr;
// Use a scope to keep the lifetime of the CachedKernel short.
{
Optional<Kernel> &CachedKernel = UniqueKernelMap[&F];
if (CachedKernel)
return *CachedKernel;
// TODO: We should use an AA to create an (optimistic and callback
// call-aware) call graph. For now we stick to simple patterns that
// are less powerful, basically the worst fixpoint.
if (isKernel(F)) {
CachedKernel = Kernel(&F);
return *CachedKernel;
}
CachedKernel = nullptr;
if (!F.hasLocalLinkage())
return nullptr;
}
auto GetUniqueKernelForUse = [&](const Use &U) -> Kernel {
if (auto *Cmp = dyn_cast<ICmpInst>(U.getUser())) {
// Allow use in equality comparisons.
if (Cmp->isEquality())
return getUniqueKernelFor(*Cmp);
return nullptr;
}
if (auto *CB = dyn_cast<CallBase>(U.getUser())) {
// Allow direct calls.
if (CB->isCallee(&U))
return getUniqueKernelFor(*CB);
// Allow the use in __kmpc_kernel_prepare_parallel calls.
if (Function *Callee = CB->getCalledFunction())
if (Callee->getName() == "__kmpc_kernel_prepare_parallel")
return getUniqueKernelFor(*CB);
return nullptr;
}
// Disallow every other use.
return nullptr;
};
// TODO: In the future we want to track more than just a unique kernel.
SmallPtrSet<Kernel, 2> PotentialKernels;
foreachUse(F, [&](const Use &U) {
PotentialKernels.insert(GetUniqueKernelForUse(U));
});
Kernel K = nullptr;
if (PotentialKernels.size() == 1)
K = *PotentialKernels.begin();
// Cache the result.
UniqueKernelMap[&F] = K;
return K;
}
bool OpenMPOpt::rewriteDeviceCodeStateMachine() {
OMPInformationCache::RuntimeFunctionInfo &KernelPrepareParallelRFI =
OMPInfoCache.RFIs[OMPRTL___kmpc_kernel_prepare_parallel];
bool Changed = false;
if (!KernelPrepareParallelRFI)
return Changed;
for (Function *F : SCC) {
// Check if the function is uses in a __kmpc_kernel_prepare_parallel call at
// all.
bool UnknownUse = false;
bool KernelPrepareUse = false;
unsigned NumDirectCalls = 0;
SmallVector<Use *, 2> ToBeReplacedStateMachineUses;
foreachUse(*F, [&](Use &U) {
if (auto *CB = dyn_cast<CallBase>(U.getUser()))
if (CB->isCallee(&U)) {
++NumDirectCalls;
return;
}
if (isa<ICmpInst>(U.getUser())) {
ToBeReplacedStateMachineUses.push_back(&U);
return;
}
if (!KernelPrepareUse && OpenMPOpt::getCallIfRegularCall(
*U.getUser(), &KernelPrepareParallelRFI)) {
KernelPrepareUse = true;
ToBeReplacedStateMachineUses.push_back(&U);
return;
}
UnknownUse = true;
});
// Do not emit a remark if we haven't seen a __kmpc_kernel_prepare_parallel
// use.
if (!KernelPrepareUse)
continue;
{
auto Remark = [&](OptimizationRemark OR) {
return OR << "Found a parallel region that is called in a target "
"region but not part of a combined target construct nor "
"nesed inside a target construct without intermediate "
"code. This can lead to excessive register usage for "
"unrelated target regions in the same translation unit "
"due to spurious call edges assumed by ptxas.";
};
emitRemarkOnFunction(F, "OpenMPParallelRegionInNonSPMD", Remark);
}
// If this ever hits, we should investigate.
// TODO: Checking the number of uses is not a necessary restriction and
// should be lifted.
if (UnknownUse || NumDirectCalls != 1 ||
ToBeReplacedStateMachineUses.size() != 2) {
{
auto Remark = [&](OptimizationRemark OR) {
return OR << "Parallel region is used in "
<< (UnknownUse ? "unknown" : "unexpected")
<< " ways; will not attempt to rewrite the state machine.";
};
emitRemarkOnFunction(F, "OpenMPParallelRegionInNonSPMD", Remark);
}
continue;
}
// Even if we have __kmpc_kernel_prepare_parallel calls, we (for now) give
// up if the function is not called from a unique kernel.
Kernel K = getUniqueKernelFor(*F);
if (!K) {
{
auto Remark = [&](OptimizationRemark OR) {
return OR << "Parallel region is not known to be called from a "
"unique single target region, maybe the surrounding "
"function has external linkage?; will not attempt to "
"rewrite the state machine use.";
};
emitRemarkOnFunction(F, "OpenMPParallelRegionInMultipleKernesl",
Remark);
}
continue;
}
// We now know F is a parallel body function called only from the kernel K.
// We also identified the state machine uses in which we replace the
// function pointer by a new global symbol for identification purposes. This
// ensures only direct calls to the function are left.
{
auto RemarkParalleRegion = [&](OptimizationRemark OR) {
return OR << "Specialize parallel region that is only reached from a "
"single target region to avoid spurious call edges and "
"excessive register usage in other target regions. "
"(parallel region ID: "
<< ore::NV("OpenMPParallelRegion", F->getName())
<< ", kernel ID: "
<< ore::NV("OpenMPTargetRegion", K->getName()) << ")";
};
emitRemarkOnFunction(F, "OpenMPParallelRegionInNonSPMD",
RemarkParalleRegion);
auto RemarkKernel = [&](OptimizationRemark OR) {
return OR << "Target region containing the parallel region that is "
"specialized. (parallel region ID: "
<< ore::NV("OpenMPParallelRegion", F->getName())
<< ", kernel ID: "
<< ore::NV("OpenMPTargetRegion", K->getName()) << ")";
};
emitRemarkOnFunction(K, "OpenMPParallelRegionInNonSPMD", RemarkKernel);
}
Module &M = *F->getParent();
Type *Int8Ty = Type::getInt8Ty(M.getContext());
auto *ID = new GlobalVariable(
M, Int8Ty, /* isConstant */ true, GlobalValue::PrivateLinkage,
UndefValue::get(Int8Ty), F->getName() + ".ID");
for (Use *U : ToBeReplacedStateMachineUses)
U->set(ConstantExpr::getBitCast(ID, U->get()->getType()));
++NumOpenMPParallelRegionsReplacedInGPUStateMachine;
Changed = true;
}
return Changed;
}
/// Abstract Attribute for tracking ICV values.
struct AAICVTracker : public StateWrapper<BooleanState, AbstractAttribute> {
using Base = StateWrapper<BooleanState, AbstractAttribute>;
AAICVTracker(const IRPosition &IRP, Attributor &A) : Base(IRP) {}
/// Returns true if value is assumed to be tracked.
bool isAssumedTracked() const { return getAssumed(); }
/// Returns true if value is known to be tracked.
bool isKnownTracked() const { return getAssumed(); }
/// Create an abstract attribute biew for the position \p IRP.
static AAICVTracker &createForPosition(const IRPosition &IRP, Attributor &A);
/// Return the value with which \p I can be replaced for specific \p ICV.
virtual Value *getReplacementValue(InternalControlVar ICV,
const Instruction *I, Attributor &A) = 0;
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAICVTracker"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AAICVTracker
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
static const char ID;
};
struct AAICVTrackerFunction : public AAICVTracker {
AAICVTrackerFunction(const IRPosition &IRP, Attributor &A)
: AAICVTracker(IRP, A) {}
// FIXME: come up with better string.
const std::string getAsStr() const override { return "ICVTracker"; }
// FIXME: come up with some stats.
void trackStatistics() const override {}
/// TODO: decide whether to deduplicate here, or use current
/// deduplicateRuntimeCalls function.
ChangeStatus manifest(Attributor &A) override {
ChangeStatus Changed = ChangeStatus::UNCHANGED;
for (InternalControlVar &ICV : TrackableICVs)
if (deduplicateICVGetters(ICV, A))
Changed = ChangeStatus::CHANGED;
return Changed;
}
bool deduplicateICVGetters(InternalControlVar &ICV, Attributor &A) {
auto &OMPInfoCache = static_cast<OMPInformationCache &>(A.getInfoCache());
auto &ICVInfo = OMPInfoCache.ICVs[ICV];
auto &GetterRFI = OMPInfoCache.RFIs[ICVInfo.Getter];
bool Changed = false;
auto ReplaceAndDeleteCB = [&](Use &U, Function &Caller) {
CallInst *CI = OpenMPOpt::getCallIfRegularCall(U, &GetterRFI);
Instruction *UserI = cast<Instruction>(U.getUser());
Value *ReplVal = getReplacementValue(ICV, UserI, A);
if (!ReplVal || !CI)
return false;
A.removeCallSite(CI);
CI->replaceAllUsesWith(ReplVal);
CI->eraseFromParent();
Changed = true;
return true;
};
GetterRFI.foreachUse(ReplaceAndDeleteCB, getAnchorScope());
return Changed;
}
// Map of ICV to their values at specific program point.
EnumeratedArray<SmallSetVector<ICVValue, 4>, InternalControlVar,
InternalControlVar::ICV___last>
ICVValuesMap;
// Currently only nthreads is being tracked.
// this array will only grow with time.
InternalControlVar TrackableICVs[1] = {ICV_nthreads};
ChangeStatus updateImpl(Attributor &A) override {
ChangeStatus HasChanged = ChangeStatus::UNCHANGED;
Function *F = getAnchorScope();
auto &OMPInfoCache = static_cast<OMPInformationCache &>(A.getInfoCache());
for (InternalControlVar ICV : TrackableICVs) {
auto &SetterRFI = OMPInfoCache.RFIs[OMPInfoCache.ICVs[ICV].Setter];
auto TrackValues = [&](Use &U, Function &) {
CallInst *CI = OpenMPOpt::getCallIfRegularCall(U);
if (!CI)
return false;
// FIXME: handle setters with more that 1 arguments.
/// Track new value.
if (ICVValuesMap[ICV].insert(ICVValue(CI, CI->getArgOperand(0))))
HasChanged = ChangeStatus::CHANGED;
return false;
};
SetterRFI.foreachUse(TrackValues, F);
}
return HasChanged;
}
/// Return the value with which \p I can be replaced for specific \p ICV.
Value *getReplacementValue(InternalControlVar ICV, const Instruction *I,
Attributor &A) override {
const BasicBlock *CurrBB = I->getParent();
auto &ValuesSet = ICVValuesMap[ICV];
auto &OMPInfoCache = static_cast<OMPInformationCache &>(A.getInfoCache());
auto &GetterRFI = OMPInfoCache.RFIs[OMPInfoCache.ICVs[ICV].Getter];
for (const auto &ICVVal : ValuesSet) {
if (CurrBB == ICVVal.Inst->getParent()) {
if (!ICVVal.Inst->comesBefore(I))
continue;
// both instructions are in the same BB and at \p I we know the ICV
// value.
while (I != ICVVal.Inst) {
// we don't yet know if a call might update an ICV.
// TODO: check callsite AA for value.
if (const auto *CB = dyn_cast<CallBase>(I))
if (CB->getCalledFunction() != GetterRFI.Declaration)
return nullptr;
I = I->getPrevNode();
}
// No call in between, return the value.
return ICVVal.TrackedValue;
}
}
// No value was tracked.
return nullptr;
}
};
} // namespace
const char AAICVTracker::ID = 0;
AAICVTracker &AAICVTracker::createForPosition(const IRPosition &IRP,
Attributor &A) {
AAICVTracker *AA = nullptr;
switch (IRP.getPositionKind()) {
case IRPosition::IRP_INVALID:
case IRPosition::IRP_FLOAT:
case IRPosition::IRP_ARGUMENT:
case IRPosition::IRP_RETURNED:
case IRPosition::IRP_CALL_SITE_RETURNED:
case IRPosition::IRP_CALL_SITE_ARGUMENT:
case IRPosition::IRP_CALL_SITE:
llvm_unreachable("ICVTracker can only be created for function position!");
case IRPosition::IRP_FUNCTION:
AA = new (A.Allocator) AAICVTrackerFunction(IRP, A);
break;
}
return *AA;
}
PreservedAnalyses OpenMPOptPass::run(LazyCallGraph::SCC &C,
CGSCCAnalysisManager &AM,
LazyCallGraph &CG, CGSCCUpdateResult &UR) {
if (!containsOpenMP(*C.begin()->getFunction().getParent(), OMPInModule))
return PreservedAnalyses::all();
if (DisableOpenMPOptimizations)
return PreservedAnalyses::all();
SmallVector<Function *, 16> SCC;
for (LazyCallGraph::Node &N : C)
SCC.push_back(&N.getFunction());
if (SCC.empty())
return PreservedAnalyses::all();
FunctionAnalysisManager &FAM =
AM.getResult<FunctionAnalysisManagerCGSCCProxy>(C, CG).getManager();
AnalysisGetter AG(FAM);
auto OREGetter = [&FAM](Function *F) -> OptimizationRemarkEmitter & {
return FAM.getResult<OptimizationRemarkEmitterAnalysis>(*F);
};
CallGraphUpdater CGUpdater;
CGUpdater.initialize(CG, C, AM, UR);
SetVector<Function *> Functions(SCC.begin(), SCC.end());
BumpPtrAllocator Allocator;
OMPInformationCache InfoCache(*(Functions.back()->getParent()), AG, Allocator,
/*CGSCC*/ Functions, OMPInModule.getKernels());
Attributor A(Functions, InfoCache, CGUpdater);
// TODO: Compute the module slice we are allowed to look at.
OpenMPOpt OMPOpt(SCC, CGUpdater, OREGetter, InfoCache, A);
bool Changed = OMPOpt.run();
if (Changed)
return PreservedAnalyses::none();
return PreservedAnalyses::all();
}
namespace {
struct OpenMPOptLegacyPass : public CallGraphSCCPass {
CallGraphUpdater CGUpdater;
OpenMPInModule OMPInModule;
static char ID;
OpenMPOptLegacyPass() : CallGraphSCCPass(ID) {
initializeOpenMPOptLegacyPassPass(*PassRegistry::getPassRegistry());
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
CallGraphSCCPass::getAnalysisUsage(AU);
}
bool doInitialization(CallGraph &CG) override {
// Disable the pass if there is no OpenMP (runtime call) in the module.
containsOpenMP(CG.getModule(), OMPInModule);
return false;
}
bool runOnSCC(CallGraphSCC &CGSCC) override {
if (!containsOpenMP(CGSCC.getCallGraph().getModule(), OMPInModule))
return false;
if (DisableOpenMPOptimizations || skipSCC(CGSCC))
return false;
SmallVector<Function *, 16> SCC;
for (CallGraphNode *CGN : CGSCC)
if (Function *Fn = CGN->getFunction())
if (!Fn->isDeclaration())
SCC.push_back(Fn);
if (SCC.empty())
return false;
CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph();
CGUpdater.initialize(CG, CGSCC);
// Maintain a map of functions to avoid rebuilding the ORE
DenseMap<Function *, std::unique_ptr<OptimizationRemarkEmitter>> OREMap;
auto OREGetter = [&OREMap](Function *F) -> OptimizationRemarkEmitter & {
std::unique_ptr<OptimizationRemarkEmitter> &ORE = OREMap[F];
if (!ORE)
ORE = std::make_unique<OptimizationRemarkEmitter>(F);
return *ORE;
};
AnalysisGetter AG;
SetVector<Function *> Functions(SCC.begin(), SCC.end());
BumpPtrAllocator Allocator;
OMPInformationCache InfoCache(
*(Functions.back()->getParent()), AG, Allocator,
/*CGSCC*/ Functions, OMPInModule.getKernels());
Attributor A(Functions, InfoCache, CGUpdater);
// TODO: Compute the module slice we are allowed to look at.
OpenMPOpt OMPOpt(SCC, CGUpdater, OREGetter, InfoCache, A);
return OMPOpt.run();
}
bool doFinalization(CallGraph &CG) override { return CGUpdater.finalize(); }
};
} // end anonymous namespace
void OpenMPInModule::identifyKernels(Module &M) {
NamedMDNode *MD = M.getOrInsertNamedMetadata("nvvm.annotations");
if (!MD)
return;
for (auto *Op : MD->operands()) {
if (Op->getNumOperands() < 2)
continue;
MDString *KindID = dyn_cast<MDString>(Op->getOperand(1));
if (!KindID || KindID->getString() != "kernel")
continue;
Function *KernelFn =
mdconst::dyn_extract_or_null<Function>(Op->getOperand(0));
if (!KernelFn)
continue;
++NumOpenMPTargetRegionKernels;
Kernels.insert(KernelFn);
}
}
bool llvm::omp::containsOpenMP(Module &M, OpenMPInModule &OMPInModule) {
if (OMPInModule.isKnown())
return OMPInModule;
// MSVC doesn't like long if-else chains for some reason and instead just
// issues an error. Work around it..
do {
#define OMP_RTL(_Enum, _Name, ...) \
if (M.getFunction(_Name)) { \
OMPInModule = true; \
break; \
}
#include "llvm/Frontend/OpenMP/OMPKinds.def"
} while (false);
// Identify kernels once. TODO: We should split the OMPInformationCache into a
// module and an SCC part. The kernel information, among other things, could
// go into the module part.
if (OMPInModule.isKnown() && OMPInModule) {
OMPInModule.identifyKernels(M);
return true;
}
return OMPInModule = false;
}
char OpenMPOptLegacyPass::ID = 0;
INITIALIZE_PASS_BEGIN(OpenMPOptLegacyPass, "openmpopt",
"OpenMP specific optimizations", false, false)
INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
INITIALIZE_PASS_END(OpenMPOptLegacyPass, "openmpopt",
"OpenMP specific optimizations", false, false)
Pass *llvm::createOpenMPOptLegacyPass() { return new OpenMPOptLegacyPass(); }