//===- llvm/unittest/IR/VerifierTest.cpp - Verifier unit tests --*- C++ -*-===//
//
// 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/IR/Verifier.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DIBuilder.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "gtest/gtest.h"

namespace llvm {
namespace {

TEST(VerifierTest, Branch_i1) {
  LLVMContext C;
  Module M("M", C);
  FunctionType *FTy = FunctionType::get(Type::getVoidTy(C), /*isVarArg=*/false);
  Function *F = Function::Create(FTy, Function::ExternalLinkage, "foo", M);
  BasicBlock *Entry = BasicBlock::Create(C, "entry", F);
  BasicBlock *Exit = BasicBlock::Create(C, "exit", F);
  ReturnInst::Create(C, Exit);

  // To avoid triggering an assertion in BranchInst::Create, we first create
  // a branch with an 'i1' condition ...

  Constant *False = ConstantInt::getFalse(C);
  BranchInst *BI = BranchInst::Create(Exit, Exit, False, Entry);

  // ... then use setOperand to redirect it to a value of different type.

  Constant *Zero32 = ConstantInt::get(IntegerType::get(C, 32), 0);
  BI->setOperand(0, Zero32);

  EXPECT_TRUE(verifyFunction(*F));
}

TEST(VerifierTest, Freeze) {
  LLVMContext C;
  Module M("M", C);
  FunctionType *FTy = FunctionType::get(Type::getVoidTy(C), /*isVarArg=*/false);
  Function *F = Function::Create(FTy, Function::ExternalLinkage, "foo", M);
  BasicBlock *Entry = BasicBlock::Create(C, "entry", F);
  ReturnInst *RI = ReturnInst::Create(C, Entry);

  IntegerType *ITy = IntegerType::get(C, 32);
  ConstantInt *CI = ConstantInt::get(ITy, 0);

  // Valid type : freeze(<2 x i32>)
  Constant *CV = ConstantVector::getSplat(ElementCount::getFixed(2), CI);
  FreezeInst *FI_vec = new FreezeInst(CV);
  FI_vec->insertBefore(RI);

  EXPECT_FALSE(verifyFunction(*F));

  FI_vec->eraseFromParent();

  // Valid type : freeze(float)
  Constant *CFP = ConstantFP::get(Type::getDoubleTy(C), 0.0);
  FreezeInst *FI_dbl = new FreezeInst(CFP);
  FI_dbl->insertBefore(RI);

  EXPECT_FALSE(verifyFunction(*F));

  FI_dbl->eraseFromParent();

  // Valid type : freeze(i32*)
  PointerType *PT = PointerType::get(ITy, 0);
  ConstantPointerNull *CPN = ConstantPointerNull::get(PT);
  FreezeInst *FI_ptr = new FreezeInst(CPN);
  FI_ptr->insertBefore(RI);

  EXPECT_FALSE(verifyFunction(*F));

  FI_ptr->eraseFromParent();

  // Valid type : freeze(int)
  FreezeInst *FI = new FreezeInst(CI);
  FI->insertBefore(RI);

  EXPECT_FALSE(verifyFunction(*F));

  FI->eraseFromParent();
}

TEST(VerifierTest, InvalidRetAttribute) {
  LLVMContext C;
  Module M("M", C);
  FunctionType *FTy = FunctionType::get(Type::getInt32Ty(C), /*isVarArg=*/false);
  Function *F = Function::Create(FTy, Function::ExternalLinkage, "foo", M);
  AttributeList AS = F->getAttributes();
  F->setAttributes(AS.addRetAttribute(
      C, Attribute::getWithUWTableKind(C, UWTableKind::Default)));

  std::string Error;
  raw_string_ostream ErrorOS(Error);
  EXPECT_TRUE(verifyModule(M, &ErrorOS));
  EXPECT_TRUE(
      StringRef(ErrorOS.str())
          .starts_with(
              "Attribute 'uwtable' does not apply to function return values"));
}

/// Test the verifier rejects invalid nofpclass values that the assembler may
/// also choose to reject.
TEST(VerifierTest, InvalidNoFPClassAttribute) {
  LLVMContext C;

  const unsigned InvalidMasks[] = {0, fcAllFlags + 1};

  for (unsigned InvalidMask : InvalidMasks) {
    Module M("M", C);
    FunctionType *FTy =
        FunctionType::get(Type::getFloatTy(C), /*isVarArg=*/false);
    Function *F = Function::Create(FTy, Function::ExternalLinkage, "foo", M);
    AttributeList AS = F->getAttributes();

    // Don't use getWithNoFPClass to avoid using out of bounds enum values here.
    F->setAttributes(AS.addRetAttribute(
        C, Attribute::get(C, Attribute::NoFPClass, InvalidMask)));

    std::string Error;
    raw_string_ostream ErrorOS(Error);
    EXPECT_TRUE(verifyModule(M, &ErrorOS));

    StringRef ErrMsg(ErrorOS.str());

    if (InvalidMask == 0) {
      EXPECT_TRUE(ErrMsg.starts_with(
          "Attribute 'nofpclass' must have at least one test bit set"))
          << ErrMsg;
    } else {
      EXPECT_TRUE(ErrMsg.starts_with("Invalid value for 'nofpclass' test mask"))
          << ErrMsg;
    }
  }
}

TEST(VerifierTest, CrossModuleRef) {
  LLVMContext C;
  Module M1("M1", C);
  Module M2("M2", C);
  Module M3("M3", C);
  FunctionType *FTy = FunctionType::get(Type::getInt32Ty(C), /*isVarArg=*/false);
  Function *F1 = Function::Create(FTy, Function::ExternalLinkage, "foo1", M1);
  Function *F2 = Function::Create(FTy, Function::ExternalLinkage, "foo2", M2);
  Function *F3 = Function::Create(FTy, Function::ExternalLinkage, "foo3", M3);

  BasicBlock *Entry1 = BasicBlock::Create(C, "entry", F1);
  BasicBlock *Entry3 = BasicBlock::Create(C, "entry", F3);

  // BAD: Referencing function in another module
  CallInst::Create(F2,"call",Entry1);

  // BAD: Referencing personality routine in another module
  F3->setPersonalityFn(F2);

  // Fill in the body
  Constant *ConstZero = ConstantInt::get(Type::getInt32Ty(C), 0);
  ReturnInst::Create(C, ConstZero, Entry1);
  ReturnInst::Create(C, ConstZero, Entry3);

  std::string Error;
  raw_string_ostream ErrorOS(Error);
  EXPECT_TRUE(verifyModule(M2, &ErrorOS));
  EXPECT_TRUE(StringRef(ErrorOS.str())
                  .equals("Global is referenced in a different module!\n"
                          "ptr @foo2\n"
                          "; ModuleID = 'M2'\n"
                          "  %call = call i32 @foo2()\n"
                          "ptr @foo1\n"
                          "; ModuleID = 'M1'\n"
                          "Global is used by function in a different module\n"
                          "ptr @foo2\n"
                          "; ModuleID = 'M2'\n"
                          "ptr @foo3\n"
                          "; ModuleID = 'M3'\n"));

  Error.clear();
  EXPECT_TRUE(verifyModule(M1, &ErrorOS));
  EXPECT_TRUE(StringRef(ErrorOS.str()).equals(
      "Referencing function in another module!\n"
      "  %call = call i32 @foo2()\n"
      "; ModuleID = 'M1'\n"
      "ptr @foo2\n"
      "; ModuleID = 'M2'\n"));

  Error.clear();
  EXPECT_TRUE(verifyModule(M3, &ErrorOS));
  EXPECT_TRUE(
      StringRef(ErrorOS.str())
          .starts_with("Referencing personality function in another module!"));

  // Erase bad methods to avoid triggering an assertion failure on destruction
  F1->eraseFromParent();
  F3->eraseFromParent();
}

TEST(VerifierTest, InvalidVariableLinkage) {
  LLVMContext C;
  Module M("M", C);
  new GlobalVariable(M, Type::getInt8Ty(C), false,
                     GlobalValue::LinkOnceODRLinkage, nullptr, "Some Global");
  std::string Error;
  raw_string_ostream ErrorOS(Error);
  EXPECT_TRUE(verifyModule(M, &ErrorOS));
  EXPECT_TRUE(StringRef(ErrorOS.str())
                  .starts_with("Global is external, but doesn't "
                               "have external or weak linkage!"));
}

TEST(VerifierTest, InvalidFunctionLinkage) {
  LLVMContext C;
  Module M("M", C);

  FunctionType *FTy = FunctionType::get(Type::getVoidTy(C), /*isVarArg=*/false);
  Function::Create(FTy, GlobalValue::LinkOnceODRLinkage, "foo", &M);
  std::string Error;
  raw_string_ostream ErrorOS(Error);
  EXPECT_TRUE(verifyModule(M, &ErrorOS));
  EXPECT_TRUE(StringRef(ErrorOS.str())
                  .starts_with("Global is external, but doesn't "
                               "have external or weak linkage!"));
}

TEST(VerifierTest, DetectInvalidDebugInfo) {
  {
    LLVMContext C;
    Module M("M", C);
    DIBuilder DIB(M);
    DIB.createCompileUnit(dwarf::DW_LANG_C89, DIB.createFile("broken.c", "/"),
                          "unittest", false, "", 0);
    DIB.finalize();
    EXPECT_FALSE(verifyModule(M));

    // Now break it by inserting non-CU node to the list of CUs.
    auto *File = DIB.createFile("not-a-CU.f", ".");
    NamedMDNode *NMD = M.getOrInsertNamedMetadata("llvm.dbg.cu");
    NMD->addOperand(File);
    EXPECT_TRUE(verifyModule(M));
  }
  {
    LLVMContext C;
    Module M("M", C);
    DIBuilder DIB(M);
    auto *CU = DIB.createCompileUnit(dwarf::DW_LANG_C89,
                                     DIB.createFile("broken.c", "/"),
                                     "unittest", false, "", 0);
    new GlobalVariable(M, Type::getInt8Ty(C), false,
                       GlobalValue::ExternalLinkage, nullptr, "g");

    auto *F = Function::Create(FunctionType::get(Type::getVoidTy(C), false),
                               Function::ExternalLinkage, "f", M);
    IRBuilder<> Builder(BasicBlock::Create(C, "", F));
    Builder.CreateUnreachable();
    F->setSubprogram(DIB.createFunction(
        CU, "f", "f", DIB.createFile("broken.c", "/"), 1, nullptr, 1,
        DINode::FlagZero,
        DISubprogram::SPFlagLocalToUnit | DISubprogram::SPFlagDefinition));
    DIB.finalize();
    EXPECT_FALSE(verifyModule(M));

    // Now break it by not listing the CU at all.
    M.eraseNamedMetadata(M.getOrInsertNamedMetadata("llvm.dbg.cu"));
    EXPECT_TRUE(verifyModule(M));
  }
}

TEST(VerifierTest, MDNodeWrongContext) {
  LLVMContext C1, C2;
  auto *Node = MDNode::get(C1, std::nullopt);

  Module M("M", C2);
  auto *NamedNode = M.getOrInsertNamedMetadata("test");
  NamedNode->addOperand(Node);

  std::string Error;
  raw_string_ostream ErrorOS(Error);
  EXPECT_TRUE(verifyModule(M, &ErrorOS));
  EXPECT_TRUE(
      StringRef(ErrorOS.str())
          .starts_with("MDNode context does not match Module context!"));
}

TEST(VerifierTest, AttributesWrongContext) {
  LLVMContext C1, C2;
  Module M1("M", C1);
  FunctionType *FTy1 =
      FunctionType::get(Type::getVoidTy(C1), /*isVarArg=*/false);
  Function *F1 = Function::Create(FTy1, Function::ExternalLinkage, "foo", M1);
  F1->setDoesNotReturn();

  Module M2("M", C2);
  FunctionType *FTy2 =
      FunctionType::get(Type::getVoidTy(C2), /*isVarArg=*/false);
  Function *F2 = Function::Create(FTy2, Function::ExternalLinkage, "foo", M2);
  F2->copyAttributesFrom(F1);

  EXPECT_TRUE(verifyFunction(*F2));
}

TEST(VerifierTest, SwitchInst) {
  LLVMContext C;
  Module M("M", C);
  IntegerType *Int32Ty = Type::getInt32Ty(C);
  FunctionType *FTy = FunctionType::get(Type::getVoidTy(C), {Int32Ty, Int32Ty},
                                        /*isVarArg=*/false);
  Function *F = Function::Create(FTy, Function::ExternalLinkage, "foo", M);
  BasicBlock *Entry = BasicBlock::Create(C, "entry", F);
  BasicBlock *Default = BasicBlock::Create(C, "default", F);
  BasicBlock *OnOne = BasicBlock::Create(C, "on_one", F);
  BasicBlock *OnTwo = BasicBlock::Create(C, "on_two", F);

  BasicBlock *Exit = BasicBlock::Create(C, "exit", F);

  BranchInst::Create(Exit, Default);
  BranchInst::Create(Exit, OnTwo);
  BranchInst::Create(Exit, OnOne);
  ReturnInst::Create(C, Exit);

  Value *Cond = F->getArg(0);
  SwitchInst *Switch = SwitchInst::Create(Cond, Default, 2, Entry);
  Switch->addCase(ConstantInt::get(Int32Ty, 1), OnOne);
  Switch->addCase(ConstantInt::get(Int32Ty, 2), OnTwo);

  EXPECT_FALSE(verifyFunction(*F));
  // set one case value to function argument.
  Switch->setOperand(2, F->getArg(1));
  EXPECT_TRUE(verifyFunction(*F));
}

} // end anonymous namespace
} // end namespace llvm