llvm-codegen-test.cc

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// Copyright 2012 Cloudera Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <string>
#include <gtest/gtest.h>
#include <boost/thread/thread.hpp>

#include "codegen/llvm-codegen.h"
#include "common/init.h"
#include "runtime/raw-value.h"
#include "util/cpu-info.h"
#include "util/hash-util.h"
#include "util/path-builder.h"

#include "common/names.h"

using namespace llvm;

namespace impala {

class LlvmCodeGenTest : public testing:: Test {
 protected:
  static void LifetimeTest() {
    ObjectPool pool;
    Status status;
    for (int i = 0; i < 10; ++i) {
      LlvmCodeGen object1(&pool, "Test");
      LlvmCodeGen object2(&pool, "Test");
      LlvmCodeGen object3(&pool, "Test");

      status = object1.Init();
      ASSERT_TRUE(status.ok());

      status = object2.Init();
      ASSERT_TRUE(status.ok());

      status = object3.Init();
      ASSERT_TRUE(status.ok());
    }
  }

  // Wrapper to call private test-only methods on LlvmCodeGen object
  static Status LoadFromFile(ObjectPool* pool, const string& filename,
      scoped_ptr<LlvmCodeGen>* codegen) {
    return LlvmCodeGen::LoadFromFile(pool, filename, "test", codegen);
  }

  static LlvmCodeGen* CreateCodegen(ObjectPool* pool) {
    LlvmCodeGen* codegen = pool->Add(new LlvmCodeGen(pool, "Test"));
    if (codegen != NULL) {
      Status status = codegen->Init();
      if (!status.ok()) return NULL;
    }
    return codegen;
  }

  static void ClearHashFns(LlvmCodeGen* codegen) {
    codegen->ClearHashFns();
  }

  static void* JitFunction(
      LlvmCodeGen* codegen, Function* function) {
    return codegen->JitFunction(function);
  }
};

// Simple test to just make and destroy llvmcodegen objects.  LLVM
// has non-obvious object ownership transfers and this sanity checks that.
TEST_F(LlvmCodeGenTest, BasicLifetime) {
  LifetimeTest();
}

// Same as above but multithreaded
TEST_F(LlvmCodeGenTest, MultithreadedLifetime) {
  const int NUM_THREADS = 10;
  thread_group thread_group;
  for (int i = 0; i < NUM_THREADS; ++i) {
    thread_group.add_thread(new thread(&LifetimeTest));
  }
  thread_group.join_all();
}

// Test loading a non-existent file
TEST_F(LlvmCodeGenTest, BadIRFile) {
  ObjectPool pool;
  string module_file = "NonExistentFile.ir";
  scoped_ptr<LlvmCodeGen> codegen;
  Status status = LlvmCodeGenTest::LoadFromFile(&pool, module_file.c_str(), &codegen);
  EXPECT_TRUE(!status.ok());
}

// IR for the generated linner loop
// define void @JittedInnerLoop() {
// entry:
//   call void @DebugTrace(i8* inttoptr (i64 18970856 to i8*))
//   %0 = load i64* inttoptr (i64 140735197627800 to i64*)
//   %1 = add i64 %0, <delta>
//   store i64 %1, i64* inttoptr (i64 140735197627800 to i64*)
//   ret void
// }
// The random int in there is the address of jitted_counter
Function* CodegenInnerLoop(LlvmCodeGen* codegen, int64_t* jitted_counter, int delta) {
  LLVMContext& context = codegen->context();
  LlvmCodeGen::LlvmBuilder builder(context);

  LlvmCodeGen::FnPrototype fn_prototype(codegen, "JittedInnerLoop", codegen->void_type());
  Function* jitted_loop_call = fn_prototype.GeneratePrototype();
  BasicBlock* entry_block = BasicBlock::Create(context, "entry", jitted_loop_call);
  builder.SetInsertPoint(entry_block);
  codegen->CodegenDebugTrace(&builder, "Jitted");

  // Store &jitted_counter as a constant.
  Value* const_delta = ConstantInt::get(context, APInt(64, delta));
  Value* counter_ptr = codegen->CastPtrToLlvmPtr(codegen->GetPtrType(TYPE_BIGINT),
      jitted_counter);
  Value* loaded_counter = builder.CreateLoad(counter_ptr);
  Value* incremented_value = builder.CreateAdd(loaded_counter, const_delta);
  builder.CreateStore(incremented_value, counter_ptr);
  builder.CreateRetVoid();

  return jitted_loop_call;
}

// This test loads a precompiled IR file (compiled from testdata/llvm/test-loop.cc).
// The test contains two functions, an outer loop function and an inner loop function.
// The outer loop calls the inner loop function.
// The test will
//   1. create a LlvmCodegen object from the precompiled file
//   2. add another function to the module with the same signature as the inner
//      loop function.
//   3. Replace the call instruction in the outer loop to a call to the new inner loop
//      function.
//   4. Run the loop and make sure the inner loop is called.
//   5. Updated the jitted loop in place with another jitted inner loop function
//   6. Run the loop and make sure the updated is called.
TEST_F(LlvmCodeGenTest, ReplaceFnCall) {
  ObjectPool pool;
  const char* loop_call_name = "DefaultImplementation";
  const char* loop_name = "TestLoop";
  typedef void (*TestLoopFn)(int);

  string module_file;
  PathBuilder::GetFullPath("llvm-ir/test-loop.ir", &module_file);

  // Part 1: Load the module and make sure everything is loaded correctly.
  scoped_ptr<LlvmCodeGen> codegen;
  Status status = LlvmCodeGenTest::LoadFromFile(&pool, module_file.c_str(), &codegen);
  EXPECT_TRUE(codegen.get() != NULL);
  EXPECT_TRUE(status.ok());

  vector<Function*> functions;
  codegen->GetFunctions(&functions);
  EXPECT_EQ(functions.size(), 2);

  Function* loop_call = functions[0];
  Function* loop = functions[1];

  EXPECT_TRUE(loop_call->getName().find(loop_call_name) != string::npos);
  EXPECT_TRUE(loop_call->arg_empty());
  EXPECT_TRUE(loop->getName().find(loop_name) != string::npos);
  EXPECT_EQ(loop->arg_size(), 1);

  void* original_loop = LlvmCodeGenTest::JitFunction(codegen.get(), loop);
  EXPECT_TRUE(original_loop != NULL);

  TestLoopFn original_loop_fn = reinterpret_cast<TestLoopFn>(original_loop);
  original_loop_fn(5);

  // Part 2: Generate a new inner loop function.
  //
  // The c++ version of the code is
  // static int64_t* counter;
  // void JittedInnerLoop() {
  //   printf("LLVM Trace: Jitted\n");
  //   ++*counter;
  // }
  //
  int64_t jitted_counter = 0;
  Function* jitted_loop_call = CodegenInnerLoop(codegen.get(), &jitted_counter, 1);

  // Part 3: Replace the call instruction to the normal function with a call to the
  // jitted one
  int num_replaced;
  Function* jitted_loop = codegen->ReplaceCallSites(
      loop, false, jitted_loop_call, loop_call_name, &num_replaced);
  EXPECT_EQ(num_replaced, 1);
  EXPECT_TRUE(codegen->VerifyFunction(jitted_loop));

  // Part4: Call the new loop and verify results
  void* new_loop = LlvmCodeGenTest::JitFunction(codegen.get(), jitted_loop);
  EXPECT_TRUE(new_loop != NULL);

  TestLoopFn new_loop_fn = reinterpret_cast<TestLoopFn>(new_loop);
  EXPECT_EQ(jitted_counter, 0);
  new_loop_fn(5);
  EXPECT_EQ(jitted_counter, 5);
  new_loop_fn(5);
  EXPECT_EQ(jitted_counter, 10);

  // Part5: Generate a new inner loop function and a new loop function in place
  Function* jitted_loop_call2 = CodegenInnerLoop(codegen.get(), &jitted_counter, -2);
  Function* jitted_loop2 = codegen->ReplaceCallSites(loop, true, jitted_loop_call2,
      loop_call_name, &num_replaced);
  EXPECT_EQ(num_replaced, 1);
  EXPECT_TRUE(codegen->VerifyFunction(jitted_loop2));

  // Part6: Call new loop
  void* new_loop2 =
      LlvmCodeGenTest::JitFunction(codegen.get(), jitted_loop2);
  EXPECT_TRUE(new_loop2 != NULL);

  TestLoopFn new_loop_fn2 = reinterpret_cast<TestLoopFn>(new_loop2);
  new_loop_fn2(5);
  EXPECT_EQ(jitted_counter, 0);
}

// Test function for c++/ir interop for strings.  Function will do:
// int StringTest(StringValue* strval) {
//   strval->ptr[0] = 'A';
//   int len = strval->len;
//   strval->len = 1;
//   return len;
// }
// Corresponding IR is:
// define i32 @StringTest(%StringValue* %str) {
// entry:
//   %str_ptr = getelementptr inbounds %StringValue* %str, i32 0, i32 0
//   %ptr = load i8** %str_ptr
//   %first_char_ptr = getelementptr i8* %ptr, i32 0
//   store i8 65, i8* %first_char_ptr
//   %len_ptr = getelementptr inbounds %StringValue* %str, i32 0, i32 1
//   %len = load i32* %len_ptr
//   store i32 1, i32* %len_ptr
//   ret i32 %len
// }
Function* CodegenStringTest(LlvmCodeGen* codegen) {
  PointerType* string_val_ptr_type = codegen->GetPtrType(TYPE_STRING);
  EXPECT_TRUE(string_val_ptr_type != NULL);

  LlvmCodeGen::FnPrototype prototype(codegen, "StringTest", codegen->GetType(TYPE_INT));
  prototype.AddArgument(LlvmCodeGen::NamedVariable("str", string_val_ptr_type));
  LlvmCodeGen::LlvmBuilder builder(codegen->context());

  Value* str;
  Function* interop_fn = prototype.GeneratePrototype(&builder, &str);

  // strval->ptr[0] = 'A'
  Value* str_ptr = builder.CreateStructGEP(str, 0, "str_ptr");
  Value* ptr = builder.CreateLoad(str_ptr, "ptr");
  Value* first_char_offset[] = { codegen->GetIntConstant(TYPE_INT, 0) };
  Value* first_char_ptr = builder.CreateGEP(ptr, first_char_offset, "first_char_ptr");
  builder.CreateStore(codegen->GetIntConstant(TYPE_TINYINT, 'A'), first_char_ptr);

  // Update and return old len
  Value* len_ptr = builder.CreateStructGEP(str, 1, "len_ptr");
  Value* len = builder.CreateLoad(len_ptr, "len");
  builder.CreateStore(codegen->GetIntConstant(TYPE_INT, 1), len_ptr);
  builder.CreateRet(len);

  return interop_fn;
}

// This test validates that the llvm StringValue struct matches the c++ stringvalue
// struct.  Just create a simple StringValue struct and make sure the IR can read it
// and modify it.
TEST_F(LlvmCodeGenTest, StringValue) {
  ObjectPool pool;

  scoped_ptr<LlvmCodeGen> codegen;
  Status status = LlvmCodeGen::LoadImpalaIR(&pool, "test", &codegen);
  EXPECT_TRUE(status.ok());
  EXPECT_TRUE(codegen.get() != NULL);

  string str("Test");

  StringValue str_val;
  // Call memset to make sure padding bits are zero.
  memset(&str_val, 0, sizeof(str_val));
  str_val.ptr = const_cast<char*>(str.c_str());
  str_val.len = str.length();

  Function* string_test_fn = CodegenStringTest(codegen.get());
  EXPECT_TRUE(string_test_fn != NULL);
  EXPECT_TRUE(codegen->VerifyFunction(string_test_fn));

  // Jit compile function
  void* jitted_fn = LlvmCodeGenTest::JitFunction(codegen.get(), string_test_fn);
  EXPECT_TRUE(jitted_fn != NULL);

  // Call IR function
  typedef int (*TestStringInteropFn)(StringValue*);
  TestStringInteropFn fn = reinterpret_cast<TestStringInteropFn>(jitted_fn);
  int result = fn(&str_val);

  // Validate
  EXPECT_EQ(str.length(), result);
  EXPECT_EQ('A', str_val.ptr[0]);
  EXPECT_EQ(1, str_val.len);
  EXPECT_EQ(static_cast<void*>(str_val.ptr), static_cast<const void*>(str.c_str()));

  // Validate padding bytes are unchanged
  int32_t* bytes = reinterpret_cast<int32_t*>(&str_val);
  EXPECT_EQ(1, bytes[2]);   // str_val.len
  EXPECT_EQ(0, bytes[3]);   // padding
}

// Test calling memcpy intrinsic
TEST_F(LlvmCodeGenTest, MemcpyTest) {
  ObjectPool pool;

  scoped_ptr<LlvmCodeGen> codegen;
  Status status = LlvmCodeGen::LoadImpalaIR(&pool, "test", &codegen);
  ASSERT_TRUE(status.ok());
  ASSERT_TRUE(codegen.get() != NULL);

  LlvmCodeGen::FnPrototype prototype(codegen.get(), "MemcpyTest", codegen->void_type());
  prototype.AddArgument(LlvmCodeGen::NamedVariable("dest", codegen->ptr_type()));
  prototype.AddArgument(LlvmCodeGen::NamedVariable("src", codegen->ptr_type()));
  prototype.AddArgument(LlvmCodeGen::NamedVariable("n", codegen->GetType(TYPE_INT)));

  LlvmCodeGen::LlvmBuilder builder(codegen->context());

  char src[] = "abcd";
  char dst[] = "aaaa";

  Value* args[3];
  Function* fn = prototype.GeneratePrototype(&builder, &args[0]);
  codegen->CodegenMemcpy(&builder, args[0], args[1], sizeof(src));
  builder.CreateRetVoid();

  fn = codegen->FinalizeFunction(fn);
  ASSERT_TRUE(fn != NULL);

  void* jitted_fn = LlvmCodeGenTest::JitFunction(codegen.get(), fn);
  ASSERT_TRUE(jitted_fn != NULL);

  typedef void (*TestMemcpyFn)(char*, char*, int64_t);
  TestMemcpyFn test_fn = reinterpret_cast<TestMemcpyFn>(jitted_fn);

  test_fn(dst, src, 4);

  EXPECT_EQ(memcmp(src, dst, 4), 0);
}

// Test codegen for hash
TEST_F(LlvmCodeGenTest, HashTest) {
  ObjectPool pool;

  // Values to compute hash on
  const char* data1 = "test string";
  const char* data2 = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

  scoped_ptr<LlvmCodeGen> codegen;
  Status status = LlvmCodeGen::LoadImpalaIR(&pool, "test", &codegen);
  ASSERT_TRUE(status.ok());
  ASSERT_TRUE(codegen.get() != NULL);

  bool restore_sse_support = false;

  Value* llvm_data1 = codegen->CastPtrToLlvmPtr(codegen->ptr_type(),
      const_cast<char*>(data1));
  Value* llvm_data2 = codegen->CastPtrToLlvmPtr(codegen->ptr_type(),
      const_cast<char*>(data2));
  Value* llvm_len1 = codegen->GetIntConstant(TYPE_INT, strlen(data1));
  Value* llvm_len2 = codegen->GetIntConstant(TYPE_INT, strlen(data2));

  // Loop to test both the sse4 on/off paths
  for (int i = 0; i < 2; ++i) {
    uint32_t expected_hash = 0;
    expected_hash = HashUtil::Hash(data1, strlen(data1), expected_hash);
    expected_hash = HashUtil::Hash(data2, strlen(data2), expected_hash);
    expected_hash = HashUtil::Hash(data1, strlen(data1), expected_hash);

    // Create a codegen'd function that hashes all the types and returns the results.
    // The tuple/values to hash are baked into the codegen for simplicity.
    LlvmCodeGen::FnPrototype prototype(codegen.get(), "HashTest",
        codegen->GetType(TYPE_INT));
    LlvmCodeGen::LlvmBuilder builder(codegen->context());

    // Test both byte-size specific hash functions and the generic loop hash function
    Function* fn_fixed = prototype.GeneratePrototype(&builder, NULL);
    Function* data1_hash_fn = codegen->GetHashFunction(strlen(data1));
    Function* data2_hash_fn = codegen->GetHashFunction(strlen(data2));
    Function* generic_hash_fn = codegen->GetHashFunction();

    ASSERT_TRUE(data1_hash_fn != NULL);
    ASSERT_TRUE(data2_hash_fn != NULL);
    ASSERT_TRUE(generic_hash_fn != NULL);

    Value* seed = codegen->GetIntConstant(TYPE_INT, 0);
    seed = builder.CreateCall3(data1_hash_fn, llvm_data1, llvm_len1, seed);
    seed = builder.CreateCall3(data2_hash_fn, llvm_data2, llvm_len2, seed);
    seed = builder.CreateCall3(generic_hash_fn, llvm_data1, llvm_len1, seed);
    builder.CreateRet(seed);

    fn_fixed = codegen->FinalizeFunction(fn_fixed);
    ASSERT_TRUE(fn_fixed != NULL);

    void* jitted_fn = LlvmCodeGenTest::JitFunction(codegen.get(), fn_fixed);
    ASSERT_TRUE(jitted_fn != NULL);

    typedef uint32_t (*TestHashFn)();
    TestHashFn test_fn = reinterpret_cast<TestHashFn>(jitted_fn);

    uint32_t result = test_fn();

    // Validate that the hashes are identical
    EXPECT_EQ(result, expected_hash) << CpuInfo::IsSupported(CpuInfo::SSE4_2);

    if (i == 0 && CpuInfo::IsSupported(CpuInfo::SSE4_2)) {
      CpuInfo::EnableFeature(CpuInfo::SSE4_2, false);
      restore_sse_support = true;
      LlvmCodeGenTest::ClearHashFns(codegen.get());
    } else {
      // System doesn't have sse, no reason to test non-sse path again.
      break;
    }
  }

  // Restore hardware feature for next test
  CpuInfo::EnableFeature(CpuInfo::SSE4_2, restore_sse_support);
}

}

int main(int argc, char **argv) {
  impala::InitCommonRuntime(argc, argv, false);
  ::testing::InitGoogleTest(&argc, argv);
  impala::LlvmCodeGen::InitializeLlvm();
  return RUN_ALL_TESTS();
}