EHFrameRegistrationPlugin.cpp

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//===--------- EHFrameRegistrationPlugin.cpp - Register eh-frames ---------===//
//
// 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/ExecutionEngine/Orc/EHFrameRegistrationPlugin.h"
 
#include "llvm/ExecutionEngine/JITLink/EHFrameSupport.h"
 
#define DEBUG_TYPE "orc"
 
using namespace llvm::jitlink;
 
namespace llvm::orc {
 
EHFrameRegistrationPlugin::EHFrameRegistrationPlugin(
    ExecutionSession &ES, std::unique_ptr<EHFrameRegistrar> Registrar)
    : ES(ES), Registrar(std::move(Registrar)) {}
 
void EHFrameRegistrationPlugin::modifyPassConfig(
    MaterializationResponsibility &MR, LinkGraph &G,
    PassConfiguration &PassConfig) {
 
  PassConfig.PostFixupPasses.push_back(createEHFrameRecorderPass(
      G.getTargetTriple(), [this, &MR](ExecutorAddr Addr, size_t Size) {
        if (Addr) {
          std::lock_guard<std::mutex> Lock(EHFramePluginMutex);
          assert(!InProcessLinks.count(&MR) &&
                 "Link for MR already being tracked?");
          InProcessLinks[&MR] = {Addr, Size};
        }
      }));
}
 
Error EHFrameRegistrationPlugin::notifyEmitted(
    MaterializationResponsibility &MR) {
 
  ExecutorAddrRange EmittedRange;
  {
    std::lock_guard<std::mutex> Lock(EHFramePluginMutex);
 
    auto EHFrameRangeItr = InProcessLinks.find(&MR);
    if (EHFrameRangeItr == InProcessLinks.end())
      return Error::success();
 
    EmittedRange = EHFrameRangeItr->second;
    assert(EmittedRange.Start && "eh-frame addr to register can not be null");
    InProcessLinks.erase(EHFrameRangeItr);
  }
 
  if (auto Err = MR.withResourceKeyDo(
          [&](ResourceKey K) { EHFrameRanges[K].push_back(EmittedRange); }))
    return Err;
 
  return Registrar->registerEHFrames(EmittedRange);
}
 
Error EHFrameRegistrationPlugin::notifyFailed(
    MaterializationResponsibility &MR) {
  std::lock_guard<std::mutex> Lock(EHFramePluginMutex);
  InProcessLinks.erase(&MR);
  return Error::success();
}
 
Error EHFrameRegistrationPlugin::notifyRemovingResources(JITDylib &JD,
                                                         ResourceKey K) {
  std::vector<ExecutorAddrRange> RangesToRemove;
 
  ES.runSessionLocked([&] {
    auto I = EHFrameRanges.find(K);
    if (I != EHFrameRanges.end()) {
      RangesToRemove = std::move(I->second);
      EHFrameRanges.erase(I);
    }
  });
 
  Error Err = Error::success();
  while (!RangesToRemove.empty()) {
    auto RangeToRemove = RangesToRemove.back();
    RangesToRemove.pop_back();
    assert(RangeToRemove.Start && "Untracked eh-frame range must not be null");
    Err = joinErrors(std::move(Err),
                     Registrar->deregisterEHFrames(RangeToRemove));
  }
 
  return Err;
}
 
void EHFrameRegistrationPlugin::notifyTransferringResources(
    JITDylib &JD, ResourceKey DstKey, ResourceKey SrcKey) {
  auto SI = EHFrameRanges.find(SrcKey);
  if (SI == EHFrameRanges.end())
    return;
 
  auto DI = EHFrameRanges.find(DstKey);
  if (DI != EHFrameRanges.end()) {
    auto &SrcRanges = SI->second;
    auto &DstRanges = DI->second;
    DstRanges.reserve(DstRanges.size() + SrcRanges.size());
    for (auto &SrcRange : SrcRanges)
      DstRanges.push_back(std::move(SrcRange));
    EHFrameRanges.erase(SI);
  } else {
    // We need to move SrcKey's ranges over without invalidating the SI
    // iterator.
    auto Tmp = std::move(SI->second);
    EHFrameRanges.erase(SI);
    EHFrameRanges[DstKey] = std::move(Tmp);
  }
}
 
} // namespace llvm::orc