// Copyright (c) 2018, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

#include "vm/compiler/backend/redundancy_elimination.h"
#include "vm/compiler/backend/il_printer.h"
#include "vm/compiler/backend/il_test_helper.h"
#include "vm/compiler/backend/inliner.h"
#include "vm/compiler/backend/loops.h"
#include "vm/compiler/backend/type_propagator.h"
#include "vm/compiler/compiler_pass.h"
#include "vm/compiler/frontend/kernel_to_il.h"
#include "vm/compiler/jit/jit_call_specializer.h"
#include "vm/log.h"
#include "vm/object.h"
#include "vm/parser.h"
#include "vm/symbols.h"
#include "vm/unit_test.h"

namespace dart {

static void NoopNative(Dart_NativeArguments args) {}

static Dart_NativeFunction NoopNativeLookup(Dart_Handle name,
                                            int argument_count,
                                            bool* auto_setup_scope) {
  ASSERT(auto_setup_scope != nullptr);
  *auto_setup_scope = false;
  return reinterpret_cast<Dart_NativeFunction>(&NoopNative);
}

// Flatten all non-captured LocalVariables from the given scope and its children
// and siblings into the given array based on their environment index.
static void FlattenScopeIntoEnvironment(FlowGraph* graph,
                                        LocalScope* scope,
                                        GrowableArray<LocalVariable*>* env) {
  for (intptr_t i = 0; i < scope->num_variables(); i++) {
    auto var = scope->VariableAt(i);
    if (var->is_captured()) {
      continue;
    }

    auto index = graph->EnvIndex(var);
    env->EnsureLength(index + 1, nullptr);
    (*env)[index] = var;
  }

  if (scope->sibling() != nullptr) {
    FlattenScopeIntoEnvironment(graph, scope->sibling(), env);
  }
  if (scope->child() != nullptr) {
    FlattenScopeIntoEnvironment(graph, scope->child(), env);
  }
}

// Run TryCatchAnalyzer optimization on the function foo from the given script
// and check that the only variables from the given list are synchronized
// on catch entry.
static void TryCatchOptimizerTest(
    Thread* thread,
    const char* script_chars,
    std::initializer_list<const char*> synchronized) {
  // Load the script and exercise the code once.
  const auto& root_library =
      Library::Handle(LoadTestScript(script_chars, &NoopNativeLookup));
  Invoke(root_library, "main");

  // Build the flow graph.
  std::initializer_list<CompilerPass::Id> passes = {
      CompilerPass::kComputeSSA,      CompilerPass::kTypePropagation,
      CompilerPass::kApplyICData,     CompilerPass::kSelectRepresentations,
      CompilerPass::kTypePropagation, CompilerPass::kCanonicalize,
  };
  const auto& function = Function::Handle(GetFunction(root_library, "foo"));
  TestPipeline pipeline(function, CompilerPass::kJIT);
  FlowGraph* graph = pipeline.RunPasses(passes);

  // Finally run TryCatchAnalyzer on the graph (in AOT mode).
  OptimizeCatchEntryStates(graph, /*is_aot=*/true);

  EXPECT_EQ(1, graph->graph_entry()->catch_entries().length());
  auto scope = graph->parsed_function().node_sequence()->scope();

  GrowableArray<LocalVariable*> env;
  FlattenScopeIntoEnvironment(graph, scope, &env);

  for (intptr_t i = 0; i < env.length(); i++) {
    bool found = false;
    for (auto name : synchronized) {
      if (env[i]->name().Equals(name)) {
        found = true;
        break;
      }
    }
    if (!found) {
      env[i] = nullptr;
    }
  }

  CatchBlockEntryInstr* catch_entry = graph->graph_entry()->catch_entries()[0];

  // We should only synchronize state for variables from the synchronized list.
  for (auto defn : *catch_entry->initial_definitions()) {
    if (ParameterInstr* param = defn->AsParameter()) {
      EXPECT(0 <= param->index() && param->index() < env.length());
      EXPECT(env[param->index()] != nullptr);
    }
  }
}

//
// Tests for TryCatchOptimizer.
//

ISOLATE_UNIT_TEST_CASE(TryCatchOptimizer_DeadParameterElimination_Simple1) {
  const char* script_chars = R"(
      dynamic blackhole([dynamic val]) native 'BlackholeNative';
      foo(int p) {
        var a = blackhole(), b = blackhole();
        try {
          blackhole([a, b]);
        } catch (e) {
          // nothing is used
        }
      }
      main() {
        foo(42);
      }
  )";

  TryCatchOptimizerTest(thread, script_chars, /*synchronized=*/{});
}

ISOLATE_UNIT_TEST_CASE(TryCatchOptimizer_DeadParameterElimination_Simple2) {
  const char* script_chars = R"(
      dynamic blackhole([dynamic val]) native 'BlackholeNative';
      foo(int p) {
        var a = blackhole(), b = blackhole();
        try {
          blackhole([a, b]);
        } catch (e) {
          // a should be synchronized
          blackhole(a);
        }
      }
      main() {
        foo(42);
      }
  )";

  TryCatchOptimizerTest(thread, script_chars, /*synchronized=*/{"a"});
}

ISOLATE_UNIT_TEST_CASE(TryCatchOptimizer_DeadParameterElimination_Cyclic1) {
  const char* script_chars = R"(
      dynamic blackhole([dynamic val]) native 'BlackholeNative';
      foo(int p) {
        var a = blackhole(), b;
        for (var i = 0; i < 42; i++) {
          b = blackhole();
          try {
            blackhole([a, b]);
          } catch (e) {
            // a and i should be synchronized
          }
        }
      }
      main() {
        foo(42);
      }
  )";

  TryCatchOptimizerTest(thread, script_chars, /*synchronized=*/{"a", "i"});
}

ISOLATE_UNIT_TEST_CASE(TryCatchOptimizer_DeadParameterElimination_Cyclic2) {
  const char* script_chars = R"(
      dynamic blackhole([dynamic val]) native 'BlackholeNative';
      foo(int p) {
        var a = blackhole(), b = blackhole();
        for (var i = 0; i < 42; i++) {
          try {
            blackhole([a, b]);
          } catch (e) {
            // a, b and i should be synchronized
          }
        }
      }
      main() {
        foo(42);
      }
  )";

  TryCatchOptimizerTest(thread, script_chars, /*synchronized=*/{"a", "b", "i"});
}

}  // namespace dart