llvm/lib/CodeGen/GCMetadata.cpp

//===-- GCMetadata.cpp - Garbage collector metadata -----------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements the GCFunctionInfo class and GCModuleInfo pass.
//
//===----------------------------------------------------------------------===//

#include "llvm/CodeGen/GCMetadata.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/IR/Function.h"
#include "llvm/InitializePasses.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Pass.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <memory>
#include <string>

using namespace llvm;

INITIALIZE_PASS(GCModuleInfo, "collector-metadata",
                "Create Garbage Collector Module Metadata", false, false)

// -----------------------------------------------------------------------------

GCFunctionInfo::GCFunctionInfo(const Function &F, GCStrategy &S)
    : F(F), S(S), FrameSize(~0LL) {}

GCFunctionInfo::~GCFunctionInfo() = default;

// -----------------------------------------------------------------------------

char GCModuleInfo::ID = 0;

GCModuleInfo::GCModuleInfo() : ImmutablePass(ID) {
  initializeGCModuleInfoPass(*PassRegistry::getPassRegistry());
}

GCFunctionInfo &GCModuleInfo::getFunctionInfo(const Function &F) {
  assert(!F.isDeclaration() && "Can only get GCFunctionInfo for a definition!");
  assert(F.hasGC());

  finfo_map_type::iterator I = FInfoMap.find(&F);
  if (I != FInfoMap.end())
    return *I->second;

  GCStrategy *S = getGCStrategy(F.getGC());
  Functions.push_back(std::make_unique<GCFunctionInfo>(F, *S));
  GCFunctionInfo *GFI = Functions.back().get();
  FInfoMap[&F] = GFI;
  return *GFI;
}

void GCModuleInfo::clear() {
  Functions.clear();
  FInfoMap.clear();
  GCStrategyList.clear();
}

// -----------------------------------------------------------------------------

GCStrategy *GCModuleInfo::getGCStrategy(const StringRef Name) {
  // TODO: Arguably, just doing a linear search would be faster for small N
  auto NMI = GCStrategyMap.find(Name);
  if (NMI != GCStrategyMap.end())
    return NMI->getValue();

  std::unique_ptr<GCStrategy> S = llvm::getGCStrategy(Name);
  S->Name = std::string(Name);
  GCStrategyMap[Name] = S.get();
  GCStrategyList.push_back(std::move(S));
  return GCStrategyList.back().get();
}