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//===- MemoryModelRelaxationAnnotations.cpp ---------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "llvm/IR/MemoryModelRelaxationAnnotations.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Metadata.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
//===- MMRAMetadata -------------------------------------------------------===//
MMRAMetadata::MMRAMetadata(const Instruction &I)
: MMRAMetadata(I.getMetadata(LLVMContext::MD_mmra)) {}
MMRAMetadata::MMRAMetadata(MDNode *MD) {
if (!MD)
return;
// TODO: Split this into a "tryParse" function that can return an err.
// CTor can use the tryParse & just fatal on err.
MDTuple *Tuple = dyn_cast<MDTuple>(MD);
assert(Tuple && "Invalid MMRA structure");
const auto HandleTagMD = [this](MDNode *TagMD) {
Tags.insert({cast<MDString>(TagMD->getOperand(0))->getString(),
cast<MDString>(TagMD->getOperand(1))->getString()});
};
if (isTagMD(Tuple)) {
HandleTagMD(Tuple);
return;
}
for (const MDOperand &Op : Tuple->operands()) {
MDNode *MDOp = cast<MDNode>(Op.get());
assert(isTagMD(MDOp));
HandleTagMD(MDOp);
}
}
bool MMRAMetadata::isTagMD(const Metadata *MD) {
if (auto *Tuple = dyn_cast<MDTuple>(MD)) {
return Tuple->getNumOperands() == 2 &&
isa<MDString>(Tuple->getOperand(0)) &&
isa<MDString>(Tuple->getOperand(1));
}
return false;
}
MDTuple *MMRAMetadata::getTagMD(LLVMContext &Ctx, StringRef Prefix,
StringRef Suffix) {
return MDTuple::get(Ctx,
{MDString::get(Ctx, Prefix), MDString::get(Ctx, Suffix)});
}
MDTuple *MMRAMetadata::getMD(LLVMContext &Ctx,
ArrayRef<MMRAMetadata::TagT> Tags) {
if (Tags.empty())
return nullptr;
if (Tags.size() == 1)
return getTagMD(Ctx, Tags.front());
SmallVector<Metadata *> MMRAs;
for (const auto &Tag : Tags)
MMRAs.push_back(getTagMD(Ctx, Tag));
return MDTuple::get(Ctx, MMRAs);
}
MDNode *MMRAMetadata::combine(LLVMContext &Ctx, const MMRAMetadata &A,
const MMRAMetadata &B) {
// Let A and B be two tags set, and U be the prefix-wise union of A and B.
// For every unique tag prefix P present in A or B:
// * If either A or B has no tags with prefix P, no tags with prefix
// P are added to U.
// * If both A and B have at least one tag with prefix P, all tags with prefix
// P from both sets are added to U.
SmallVector<Metadata *> Result;
for (const auto &[P, S] : A) {
if (B.hasTagWithPrefix(P))
Result.push_back(getTagMD(Ctx, P, S));
}
for (const auto &[P, S] : B) {
if (A.hasTagWithPrefix(P))
Result.push_back(getTagMD(Ctx, P, S));
}
return MDTuple::get(Ctx, Result);
}
bool MMRAMetadata::hasTag(StringRef Prefix, StringRef Suffix) const {
return Tags.count({Prefix, Suffix});
}
bool MMRAMetadata::isCompatibleWith(const MMRAMetadata &Other) const {
// Two sets of tags are compatible iff, for every unique tag prefix P
// present in at least one set:
// - the other set contains no tag with prefix P, or
// - at least one tag with prefix P is common to both sets.
StringMap<bool> PrefixStatuses;
for (const auto &[P, S] : Tags)
PrefixStatuses[P] |= (Other.hasTag(P, S) || !Other.hasTagWithPrefix(P));
for (const auto &[P, S] : Other)
PrefixStatuses[P] |= (hasTag(P, S) || !hasTagWithPrefix(P));
for (auto &[Prefix, Status] : PrefixStatuses) {
if (!Status)
return false;
}
return true;
}
bool MMRAMetadata::hasTagWithPrefix(StringRef Prefix) const {
for (const auto &[P, S] : Tags)
if (P == Prefix)
return true;
return false;
}
MMRAMetadata::const_iterator MMRAMetadata::begin() const {
return Tags.begin();
}
MMRAMetadata::const_iterator MMRAMetadata::end() const { return Tags.end(); }
bool MMRAMetadata::empty() const { return Tags.empty(); }
unsigned MMRAMetadata::size() const { return Tags.size(); }
void MMRAMetadata::print(raw_ostream &OS) const {
bool IsFirst = true;
// TODO: use map_iter + join
for (const auto &[P, S] : Tags) {
if (IsFirst)
IsFirst = false;
else
OS << ", ";
OS << P << ":" << S;
}
}
LLVM_DUMP_METHOD
void MMRAMetadata::dump() const { print(dbgs()); }
//===- Helpers ------------------------------------------------------------===//
static bool isReadWriteMemCall(const Instruction &I) {
if (const auto *C = dyn_cast<CallBase>(&I))
return C->mayReadOrWriteMemory() ||
!C->getMemoryEffects().doesNotAccessMemory();
return false;
}
bool llvm::canInstructionHaveMMRAs(const Instruction &I) {
return isa<LoadInst>(I) || isa<StoreInst>(I) || isa<AtomicCmpXchgInst>(I) ||
isa<AtomicRMWInst>(I) || isa<FenceInst>(I) || isReadWriteMemCall(I);
}
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