examples/LLVMPrintFunctionNames/LLVMPrintFunctionNames.cpp

//===- LLVMPrintFunctionNames.cpp
//---------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Example clang plugin which simply prints the names of all the functions
// within the generated LLVM code.
//
//===----------------------------------------------------------------------===//

#include "clang/AST/AST.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/FrontendPluginRegistry.h"
#include "clang/Sema/Sema.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Passes/OptimizationLevel.h"
#include "llvm/Passes/PassBuilder.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;

namespace {

class PrintPass final : public llvm::AnalysisInfoMixin<PrintPass> {
  friend struct llvm::AnalysisInfoMixin<PrintPass>;

public:
  using Result = llvm::PreservedAnalyses;

  Result run(llvm::Module &M, llvm::ModuleAnalysisManager &MAM) {
    for (auto &F : M)
      llvm::outs() << "[PrintPass] Found function: " << F.getName() << "\n";
    return llvm::PreservedAnalyses::all();
  }
  static bool isRequired() { return true; }
};

void PrintCallback(llvm::PassBuilder &PB) {
  PB.registerPipelineStartEPCallback(
      [](llvm::ModulePassManager &MPM, llvm::OptimizationLevel) {
        MPM.addPass(PrintPass());
      });
}

class LLVMPrintFunctionsConsumer : public ASTConsumer {
public:
  LLVMPrintFunctionsConsumer(CompilerInstance &Instance) {
    Instance.getCodeGenOpts().PassBuilderCallbacks.push_back(PrintCallback);
  }
};

class LLVMPrintFunctionNamesAction : public PluginASTAction {
protected:
  std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
                                                 llvm::StringRef) override {
    return std::make_unique<LLVMPrintFunctionsConsumer>(CI);
  }
  bool ParseArgs(const CompilerInstance &,
                 const std::vector<std::string> &) override {
    return true;
  }
  PluginASTAction::ActionType getActionType() override {
    return AddBeforeMainAction;
  }
};

} // namespace

static FrontendPluginRegistry::Add<LLVMPrintFunctionNamesAction>
    X("llvm-print-fns", "print function names, llvm level");