llvm/llvm/lib/Target/AMDGPU/AMDGPUCtorDtorLowering.cpp

//===-- AMDGPUCtorDtorLowering.cpp - Handle global ctors and dtors --------===//
//
// 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
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This pass creates a unified init and fini kernel with the required metadata
//===----------------------------------------------------------------------===//

#include "AMDGPUCtorDtorLowering.h"
#include "AMDGPU.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Value.h"
#include "llvm/Pass.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"

usingnamespacellvm;

#define DEBUG_TYPE …

namespace {

static Function *createInitOrFiniKernelFunction(Module &M, bool IsCtor) { … }

// The linker will provide the associated symbols to allow us to traverse the
// global constructors / destructors in priority order. We create the IR
// required to call each callback in this section. This is equivalent to the
// following code.
//
// extern "C" void * __init_array_start[];
// extern "C" void * __init_array_end[];
// extern "C" void * __fini_array_start[];
// extern "C" void * __fini_array_end[];
//
// using InitCallback = void();
// using FiniCallback = void(void);
//
// void call_init_array_callbacks() {
//   for (auto start = __init_array_start; start != __init_array_end; ++start)
//     reinterpret_cast<InitCallback *>(*start)();
// }
//
// void call_fini_array_callbacks() {
//  size_t fini_array_size = __fini_array_end - __fini_array_start;
//  for (size_t i = fini_array_size; i > 0; --i)
//    reinterpret_cast<FiniCallback *>(__fini_array_start[i - 1])();
// }
static void createInitOrFiniCalls(Function &F, bool IsCtor) { … }

static bool createInitOrFiniKernel(Module &M, StringRef GlobalName,
                                   bool IsCtor) { … }

static bool lowerCtorsAndDtors(Module &M) { … }

class AMDGPUCtorDtorLoweringLegacy final : public ModulePass { … };

} // End anonymous namespace

PreservedAnalyses AMDGPUCtorDtorLoweringPass::run(Module &M,
                                                  ModuleAnalysisManager &AM) { … }

char AMDGPUCtorDtorLoweringLegacy::ID = …;
char &llvm::AMDGPUCtorDtorLoweringLegacyPassID = …;
INITIALIZE_PASS(…)

ModulePass *llvm::createAMDGPUCtorDtorLoweringLegacyPass() { … }