//===- CodeExtractor.cpp - Unit tests for CodeExtractor -------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "llvm/Transforms/Utils/CodeExtractor.h"
#include "llvm/AsmParser/Parser.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
#include "llvm/IRReader/IRReader.h"
#include "llvm/Support/SourceMgr.h"
#include "gtest/gtest.h"

using namespace llvm;

namespace {
BasicBlock *getBlockByName(Function *F, StringRef name) {
  for (auto &BB : *F)
    if (BB.getName() == name)
      return &BB;
  return nullptr;
}

TEST(CodeExtractor, ExitStub) {
  LLVMContext Ctx;
  SMDiagnostic Err;
  std::unique_ptr<Module> M(parseAssemblyString(R"invalid(
    define i32 @foo(i32 %x, i32 %y, i32 %z) {
    header:
      %0 = icmp ugt i32 %x, %y
      br i1 %0, label %body1, label %body2

    body1:
      %1 = add i32 %z, 2
      br label %notExtracted

    body2:
      %2 = mul i32 %z, 7
      br label %notExtracted

    notExtracted:
      %3 = phi i32 [ %1, %body1 ], [ %2, %body2 ]
      %4 = add i32 %3, %x
      ret i32 %4
    }
  )invalid",
                                                Err, Ctx));

  Function *Func = M->getFunction("foo");
  SmallVector<BasicBlock *, 3> Candidates{ getBlockByName(Func, "header"),
                                           getBlockByName(Func, "body1"),
                                           getBlockByName(Func, "body2") };

  DominatorTree DT(*Func);
  CodeExtractor CE(Candidates, &DT);
  EXPECT_TRUE(CE.isEligible());

  Function *Outlined = CE.extractCodeRegion();
  EXPECT_TRUE(Outlined);
  BasicBlock *Exit = getBlockByName(Func, "notExtracted");
  BasicBlock *ExitSplit = getBlockByName(Outlined, "notExtracted.split");
  // Ensure that PHI in exit block has only one incoming value (from code
  // replacer block).
  EXPECT_TRUE(Exit && cast<PHINode>(Exit->front()).getNumIncomingValues() == 1);
  // Ensure that there is a PHI in outlined function with 2 incoming values.
  EXPECT_TRUE(ExitSplit &&
              cast<PHINode>(ExitSplit->front()).getNumIncomingValues() == 2);
  EXPECT_FALSE(verifyFunction(*Outlined));
  EXPECT_FALSE(verifyFunction(*Func));
}

TEST(CodeExtractor, ExitPHIOnePredFromRegion) {
  LLVMContext Ctx;
  SMDiagnostic Err;
  std::unique_ptr<Module> M(parseAssemblyString(R"invalid(
    define i32 @foo() {
    header:
      br i1 undef, label %extracted1, label %pred

    pred:
      br i1 undef, label %exit1, label %exit2

    extracted1:
      br i1 undef, label %extracted2, label %exit1

    extracted2:
      br label %exit2

    exit1:
      %0 = phi i32 [ 1, %extracted1 ], [ 2, %pred ]
      ret i32 %0

    exit2:
      %1 = phi i32 [ 3, %extracted2 ], [ 4, %pred ]
      ret i32 %1
    }
  )invalid", Err, Ctx));

  Function *Func = M->getFunction("foo");
  SmallVector<BasicBlock *, 2> ExtractedBlocks{
    getBlockByName(Func, "extracted1"),
    getBlockByName(Func, "extracted2")
  };

  DominatorTree DT(*Func);
  CodeExtractor CE(ExtractedBlocks, &DT);
  EXPECT_TRUE(CE.isEligible());

  Function *Outlined = CE.extractCodeRegion();
  EXPECT_TRUE(Outlined);
  BasicBlock *Exit1 = getBlockByName(Func, "exit1");
  BasicBlock *Exit2 = getBlockByName(Func, "exit2");
  // Ensure that PHIs in exits are not splitted (since that they have only one
  // incoming value from extracted region).
  EXPECT_TRUE(Exit1 &&
          cast<PHINode>(Exit1->front()).getNumIncomingValues() == 2);
  EXPECT_TRUE(Exit2 &&
          cast<PHINode>(Exit2->front()).getNumIncomingValues() == 2);
  EXPECT_FALSE(verifyFunction(*Outlined));
  EXPECT_FALSE(verifyFunction(*Func));
}
} // end anonymous namespace