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//===------ PollyIRBuilder.cpp --------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// The Polly IRBuilder file contains Polly specific extensions for the IRBuilder
// that are used e.g. to emit the llvm.loop.parallel metadata.
//
//===----------------------------------------------------------------------===//
#include "polly/CodeGen/IRBuilder.h"
#include "polly/ScopInfo.h"
#include "polly/Support/ScopHelper.h"
#include "llvm/IR/Metadata.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
using namespace polly;
/// @brief Get a self referencing id metadata node.
///
/// The MDNode looks like this (if arg0/arg1 are not null):
///
/// '!n = metadata !{metadata !n, arg0, arg1}'
///
/// @return The self referencing id metadata node.
static MDNode *getID(LLVMContext &Ctx, Metadata *arg0 = nullptr,
Metadata *arg1 = nullptr) {
MDNode *ID;
SmallVector<Metadata *, 3> Args;
// Use a temporary node to safely create a unique pointer for the first arg.
auto TempNode = MDNode::getTemporary(Ctx, None);
// Reserve operand 0 for loop id self reference.
Args.push_back(TempNode.get());
if (arg0)
Args.push_back(arg0);
if (arg1)
Args.push_back(arg1);
ID = MDNode::get(Ctx, Args);
ID->replaceOperandWith(0, ID);
return ID;
}
ScopAnnotator::ScopAnnotator() : SE(nullptr), AliasScopeDomain(nullptr) {}
void ScopAnnotator::buildAliasScopes(Scop &S) {
SE = S.getSE();
LLVMContext &Ctx = SE->getContext();
AliasScopeDomain = getID(Ctx, MDString::get(Ctx, "polly.alias.scope.domain"));
AliasScopeMap.clear();
OtherAliasScopeListMap.clear();
SetVector<Value *> BasePtrs;
for (ScopStmt &Stmt : S)
for (MemoryAccess *MA : Stmt)
BasePtrs.insert(MA->getBaseAddr());
std::string AliasScopeStr = "polly.alias.scope.";
for (Value *BasePtr : BasePtrs)
AliasScopeMap[BasePtr] = getID(
Ctx, AliasScopeDomain,
MDString::get(Ctx, (AliasScopeStr + BasePtr->getName()).str().c_str()));
for (Value *BasePtr : BasePtrs) {
MDNode *AliasScopeList = MDNode::get(Ctx, {});
for (const auto &AliasScopePair : AliasScopeMap) {
if (BasePtr == AliasScopePair.first)
continue;
Metadata *Args = {AliasScopePair.second};
AliasScopeList =
MDNode::concatenate(AliasScopeList, MDNode::get(Ctx, Args));
}
OtherAliasScopeListMap[BasePtr] = AliasScopeList;
}
}
void ScopAnnotator::pushLoop(Loop *L, bool IsParallel) {
ActiveLoops.push_back(L);
if (!IsParallel)
return;
BasicBlock *Header = L->getHeader();
MDNode *Id = getID(Header->getContext());
assert(Id->getOperand(0) == Id && "Expected Id to be a self-reference");
assert(Id->getNumOperands() == 1 && "Unexpected extra operands in Id");
MDNode *Ids = ParallelLoops.empty()
? Id
: MDNode::concatenate(ParallelLoops.back(), Id);
ParallelLoops.push_back(Ids);
}
void ScopAnnotator::popLoop(bool IsParallel) {
ActiveLoops.pop_back();
if (!IsParallel)
return;
assert(!ParallelLoops.empty() && "Expected a parallel loop to pop");
ParallelLoops.pop_back();
}
void ScopAnnotator::annotateLoopLatch(BranchInst *B, Loop *L,
bool IsParallel) const {
if (!IsParallel)
return;
assert(!ParallelLoops.empty() && "Expected a parallel loop to annotate");
MDNode *Ids = ParallelLoops.back();
MDNode *Id = cast<MDNode>(Ids->getOperand(Ids->getNumOperands() - 1));
B->setMetadata("llvm.loop", Id);
}
void ScopAnnotator::annotate(Instruction *Inst) {
if (!Inst->mayReadOrWriteMemory())
return;
if (!ParallelLoops.empty())
Inst->setMetadata("llvm.mem.parallel_loop_access", ParallelLoops.back());
// TODO: Use the ScopArrayInfo once available here.
if (!AliasScopeDomain)
return;
if (!(isa<StoreInst>(Inst) || isa<LoadInst>(Inst)))
return;
auto *PtrSCEV = SE->getSCEV(getPointerOperand(*Inst));
auto *BaseSCEV = SE->getPointerBase(PtrSCEV);
auto *SU = dyn_cast<SCEVUnknown>(BaseSCEV);
if (!SU)
return;
auto *BasePtr = SU->getValue();
if (!BasePtr)
return;
auto AliasScopeIterator = AliasScopeMap.find(BasePtr);
if (AliasScopeIterator == AliasScopeMap.end()) {
auto I = AlternativeAliasBases.find(BasePtr);
if (I == AlternativeAliasBases.end())
return;
BasePtr = I->second;
AliasScopeIterator = AliasScopeMap.find(BasePtr);
if (AliasScopeIterator == AliasScopeMap.end())
return;
}
auto AliasScope = AliasScopeIterator->second;
assert(OtherAliasScopeListMap.count(BasePtr) &&
"BasePtr either expected in AliasScopeMap and OtherAlias...Map");
auto *OtherAliasScopeList = OtherAliasScopeListMap[BasePtr];
Inst->setMetadata("alias.scope", AliasScope);
Inst->setMetadata("noalias", OtherAliasScopeList);
}
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