FunctionAnalysisManagerCGSCCProxyTest.cpp

#include "gtest/gtest.h"
#include "llvm/Analysis/PostDominators.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/NoFolder.h"
#include "llvm/Passes/PassBuilder.h"

static void createCalls(llvm::LLVMContext &context, llvm::Module &module) {
  llvm::Type *voidType = llvm::Type::getVoidTy(context);
  llvm::GlobalValue::LinkageTypes linkage = llvm::GlobalValue::ExternalLinkage;
  llvm::FunctionType *functionType = llvm::FunctionType::get(voidType, false);
  llvm::Function *one =
      llvm::Function::Create(functionType, linkage, "one", module);
  llvm::BasicBlock::Create(context, "entry", one);
  llvm::Function *two =
      llvm::Function::Create(functionType, linkage, "two", module);
  llvm::BasicBlock::Create(context, "entry", two);
  llvm::Function *three =
      llvm::Function::Create(functionType, linkage, "three", module);
  llvm::BasicBlock::Create(context, "entry", three);
  llvm::Function *four =
      llvm::Function::Create(functionType, linkage, "four", module);
  llvm::BasicBlock::Create(context, "entry", four);

  llvm::IRBuilder<llvm::NoFolder> builder(&one->getEntryBlock());
  builder.CreateCall(two, llvm::None);

  builder.SetInsertPoint(&two->getEntryBlock());
  builder.CreateCall(three, llvm::None);

  builder.SetInsertPoint(&three->getEntryBlock());
  builder.CreateCall(one, llvm::None);
}

class MyCGSCCPass : public llvm::PassInfoMixin<MyCGSCCPass> {
public:
  llvm::PreservedAnalyses run(llvm::LazyCallGraph::SCC &C,
                              llvm::CGSCCAnalysisManager &AM,
                              llvm::LazyCallGraph &CG,
                              llvm::CGSCCUpdateResult &UR) {
    llvm::FunctionAnalysisManager &FAM =
        AM.getResult<llvm::FunctionAnalysisManagerCGSCCProxy>(C, CG)
            .getManager();
    for (llvm::LazyCallGraph::Node &N : C) {
      llvm::Function &F = N.getFunction();
      llvm::PostDominatorTree &PDT =
          FAM.getResult<llvm::PostDominatorTreeAnalysis>(F);
      PDT.print(llvm::outs());
    }
    return llvm::PreservedAnalyses::none();
  }
};

TEST(FunctionAnalysisManagerCGSCCProxyTest, example) {
  llvm::LLVMContext context;
  llvm::Module module("Test module", context);
  createCalls(context, module);

  llvm::PassBuilder passBuilder;
  llvm::LoopAnalysisManager loopAnalysisManager;
  llvm::CGSCCAnalysisManager cgsccAnalysisManager;
  llvm::FunctionAnalysisManager functionAnalysisManager;
  llvm::ModuleAnalysisManager moduleAnalysisManager;

  passBuilder.registerLoopAnalyses(loopAnalysisManager);
  passBuilder.registerCGSCCAnalyses(cgsccAnalysisManager);
  passBuilder.registerFunctionAnalyses(functionAnalysisManager);
  passBuilder.registerModuleAnalyses(moduleAnalysisManager);

  passBuilder.crossRegisterProxies(loopAnalysisManager, functionAnalysisManager,
                                   cgsccAnalysisManager, moduleAnalysisManager);

  llvm::CGSCCPassManager cgsccPassManager;
  cgsccPassManager.addPass(MyCGSCCPass());

  llvm::ModulePassManager modulePassManager;
  modulePassManager.addPass(llvm::createModuleToPostOrderCGSCCPassAdaptor(
      std::move(cgsccPassManager)));

  // Prints the following:
  // =============================--------------------------------
  // Inorder PostDominator Tree: DFSNumbers invalid: 0 slow queries.
  //   [1]  <<exit node>> {4294967295,4294967295} [0]
  //     [2] %entry {4294967295,4294967295} [1]
  // Roots: %entry
  // =============================--------------------------------
  // Inorder PostDominator Tree: DFSNumbers invalid: 0 slow queries.
  //   [1]  <<exit node>> {4294967295,4294967295} [0]
  //     [2] %entry {4294967295,4294967295} [1]
  // Roots: %entry
  // =============================--------------------------------
  // Inorder PostDominator Tree: DFSNumbers invalid: 0 slow queries.
  //   [1]  <<exit node>> {4294967295,4294967295} [0]
  //     [2] %entry {4294967295,4294967295} [1]
  // Roots: %entry
  // =============================--------------------------------
  // Inorder PostDominator Tree: DFSNumbers invalid: 0 slow queries.
  //   [1]  <<exit node>> {4294967295,4294967295} [0]
  //     [2] %entry {4294967295,4294967295} [1]
  // Roots: %entry
  modulePassManager.run(module, moduleAnalysisManager);
}