llvm-project/llvm/unittests/Analysis/PluginInlineAdvisorAnalysisTest.cpp

#include "llvm/Analysis/CallGraph.h"
#include "llvm/AsmParser/Parser.h"
#include "llvm/Config/config.h"
#include "llvm/Passes/PassBuilder.h"
#include "llvm/Passes/PassPlugin.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Testing/Support/Error.h"
#include "gtest/gtest.h"

namespace llvm {

namespace {

void anchor() {}

static std::string libPath(const std::string Name = "InlineAdvisorPlugin") {
  const auto &Argvs = testing::internal::GetArgvs();
  const char *Argv0 =
      Argvs.size() > 0 ? Argvs[0].c_str() : "PluginInlineAdvisorAnalysisTest";
  void *Ptr = (void *)(intptr_t)anchor;
  std::string Path = sys::fs::getMainExecutable(Argv0, Ptr);
  llvm::SmallString<256> Buf{sys::path::parent_path(Path)};
  sys::path::append(Buf, (Name + LLVM_PLUGIN_EXT).c_str());
  return std::string(Buf.str());
}

// Example of a custom InlineAdvisor that only inlines calls to functions called
// "foo".
class FooOnlyInlineAdvisor : public InlineAdvisor {
public:
  FooOnlyInlineAdvisor(Module &M, FunctionAnalysisManager &FAM,
                       InlineParams Params, InlineContext IC)
      : InlineAdvisor(M, FAM, IC) {}

  std::unique_ptr<InlineAdvice> getAdviceImpl(CallBase &CB) override {
    if (CB.getCalledFunction()->getName() == "foo")
      return std::make_unique<InlineAdvice>(this, CB, getCallerORE(CB), true);
    return std::make_unique<InlineAdvice>(this, CB, getCallerORE(CB), false);
  }
};

static InlineAdvisor *fooOnlyFactory(Module &M, FunctionAnalysisManager &FAM,
                                     InlineParams Params, InlineContext IC) {
  return new FooOnlyInlineAdvisor(M, FAM, Params, IC);
}

struct CompilerInstance {
  LLVMContext Ctx;
  ModulePassManager MPM;
  InlineParams IP;

  PassBuilder PB;
  LoopAnalysisManager LAM;
  FunctionAnalysisManager FAM;
  CGSCCAnalysisManager CGAM;
  ModuleAnalysisManager MAM;

  SMDiagnostic Error;

  // connect the plugin to our compiler instance
  void setupPlugin() {
    auto PluginPath = libPath();
    ASSERT_NE("", PluginPath);
    Expected<PassPlugin> Plugin = PassPlugin::Load(PluginPath);
    ASSERT_TRUE(!!Plugin) << "Plugin path: " << PluginPath;
    Plugin->registerPassBuilderCallbacks(PB);
    ASSERT_THAT_ERROR(PB.parsePassPipeline(MPM, "dynamic-inline-advisor"),
                      Succeeded());
  }

  // connect the FooOnlyInlineAdvisor to our compiler instance
  void setupFooOnly() {
    MAM.registerPass(
        [&] { return PluginInlineAdvisorAnalysis(fooOnlyFactory); });
  }

  CompilerInstance() {
    IP = getInlineParams(3, 0);
    PB.registerModuleAnalyses(MAM);
    PB.registerCGSCCAnalyses(CGAM);
    PB.registerFunctionAnalyses(FAM);
    PB.registerLoopAnalyses(LAM);
    PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
    MPM.addPass(ModuleInlinerPass(IP, InliningAdvisorMode::Default,
                                  ThinOrFullLTOPhase::None));
  }

  ~CompilerInstance() {
    // Reset the static variable that tracks if the plugin has been registered.
    // This is needed to allow the test to run multiple times.
    PluginInlineAdvisorAnalysis::HasBeenRegistered = false;
  }

  std::string output;
  std::unique_ptr<Module> outputM;

  // run with the default inliner
  auto run_default(StringRef IR) {
    PluginInlineAdvisorAnalysis::HasBeenRegistered = false;
    outputM = parseAssemblyString(IR, Error, Ctx);
    MPM.run(*outputM, MAM);
    ASSERT_TRUE(outputM);
    output.clear();
    raw_string_ostream o_stream{output};
    outputM->print(o_stream, nullptr);
    ASSERT_TRUE(true);
  }

  // run with the dnamic inliner
  auto run_dynamic(StringRef IR) {
    // note typically the constructor for the DynamicInlineAdvisorAnalysis
    // will automatically set this to true, we controll it here only to
    // altenate between the default and dynamic inliner in our test
    PluginInlineAdvisorAnalysis::HasBeenRegistered = true;
    outputM = parseAssemblyString(IR, Error, Ctx);
    MPM.run(*outputM, MAM);
    ASSERT_TRUE(outputM);
    output.clear();
    raw_string_ostream o_stream{output};
    outputM->print(o_stream, nullptr);
    ASSERT_TRUE(true);
  }
};

StringRef TestIRS[] = {
    // Simple 3 function inline case
    R"(
define void @f1() {
  call void @foo()
  ret void
}
define void @foo() {
  call void @f3()
  ret void
}
define void @f3() {
  ret void
}
  )",
    // Test that has 5 functions of which 2 are recursive
    R"(
define void @f1() {
  call void @foo()
  ret void
}
define void @f2() {
  call void @foo()
  ret void
}
define void @foo() {
  call void @f4()
  call void @f5()
  ret void
}
define void @f4() {
  ret void
}
define void @f5() {
  call void @foo()
  ret void
}
  )",
    // test with 2 mutually recursive functions and 1 function with a loop
    R"(
define void @f1() {
  call void @f2()
  ret void
}
define void @f2() {
  call void @f3()
  ret void
}
define void @f3() {
  call void @f1()
  ret void
}
define void @f4() {
  br label %loop
loop:
  call void @f5()
  br label %loop
}
define void @f5() {
  ret void
}
  )",
    // test that has a function that computes fibonacci in a loop, one in a
    // recurisve manner, and one that calls both and compares them
    R"(
define i32 @fib_loop(i32 %n){
    %curr = alloca i32
    %last = alloca i32
    %i = alloca i32
    store i32 1, i32* %curr
    store i32 1, i32* %last
    store i32 2, i32* %i
    br label %loop_cond
  loop_cond:
    %i_val = load i32, i32* %i
    %cmp = icmp slt i32 %i_val, %n
    br i1 %cmp, label %loop_body, label %loop_end
  loop_body:
    %curr_val = load i32, i32* %curr
    %last_val = load i32, i32* %last
    %add = add i32 %curr_val, %last_val
    store i32 %add, i32* %last
    store i32 %curr_val, i32* %curr
    %i_val2 = load i32, i32* %i
    %add2 = add i32 %i_val2, 1
    store i32 %add2, i32* %i
    br label %loop_cond
  loop_end:
    %curr_val3 = load i32, i32* %curr
    ret i32 %curr_val3
}

define i32 @fib_rec(i32 %n){
    %cmp = icmp eq i32 %n, 0
    %cmp2 = icmp eq i32 %n, 1
    %or = or i1 %cmp, %cmp2
    br i1 %or, label %if_true, label %if_false
  if_true:
    ret i32 1
  if_false:
    %sub = sub i32 %n, 1
    %call = call i32 @fib_rec(i32 %sub)
    %sub2 = sub i32 %n, 2
    %call2 = call i32 @fib_rec(i32 %sub2)
    %add = add i32 %call, %call2
    ret i32 %add
}

define i32 @fib_check(){
    %correct = alloca i32
    %i = alloca i32
    store i32 1, i32* %correct
    store i32 0, i32* %i
    br label %loop_cond
  loop_cond:
    %i_val = load i32, i32* %i
    %cmp = icmp slt i32 %i_val, 10
    br i1 %cmp, label %loop_body, label %loop_end
  loop_body:
    %i_val2 = load i32, i32* %i
    %call = call i32 @fib_loop(i32 %i_val2)
    %i_val3 = load i32, i32* %i
    %call2 = call i32 @fib_rec(i32 %i_val3)
    %cmp2 = icmp ne i32 %call, %call2
    br i1 %cmp2, label %if_true, label %if_false
  if_true:
    store i32 0, i32* %correct
    br label %if_end
  if_false:
    br label %if_end
  if_end:
    %i_val4 = load i32, i32* %i
    %add = add i32 %i_val4, 1
    store i32 %add, i32* %i
    br label %loop_cond
  loop_end:
    %correct_val = load i32, i32* %correct
    ret i32 %correct_val
}
  )"};

} // namespace

// check that loading a plugin works
// the plugin being loaded acts identically to the default inliner
TEST(PluginInlineAdvisorTest, PluginLoad) {
#if !defined(LLVM_ENABLE_PLUGINS)
  // Skip the test if plugins are disabled.
  GTEST_SKIP();
#endif
  CompilerInstance CI{};
  CI.setupPlugin();

  for (StringRef IR : TestIRS) {
    CI.run_default(IR);
    std::string default_output = CI.output;
    CI.run_dynamic(IR);
    std::string dynamic_output = CI.output;
    ASSERT_EQ(default_output, dynamic_output);
  }
}

// check that the behaviour of a custom inliner is correct
// the custom inliner inlines all functions that are not named "foo"
// this testdoes not require plugins to be enabled
TEST(PluginInlineAdvisorTest, CustomAdvisor) {
  CompilerInstance CI{};
  CI.setupFooOnly();

  for (StringRef IR : TestIRS) {
    CI.run_dynamic(IR);
    CallGraph CGraph = CallGraph(*CI.outputM);
    for (auto &node : CGraph) {
      for (auto &edge : *node.second) {
        if (!edge.first)
          continue;
        ASSERT_NE(edge.second->getFunction()->getName(), "foo");
      }
    }
  }
}

} // namespace llvm