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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=8 sts=2 et sw=2 tw=80:
 *
 * Copyright 2015 Mozilla Foundation
 *
 * 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.
 */

#ifndef wasm_generator_h
#define wasm_generator_h

#include "mozilla/MemoryReporting.h"

#include "jit/MacroAssembler.h"
#include "wasm/WasmCompile.h"
#include "wasm/WasmModule.h"
#include "wasm/WasmValidate.h"

namespace js {
namespace wasm {

struct CompileTask;
typedef Vector<CompileTask*, 0, SystemAllocPolicy> CompileTaskPtrVector;

// FuncCompileInput contains the input for compiling a single function.

struct FuncCompileInput {
  const uint8_t* begin;
  const uint8_t* end;
  uint32_t index;
  uint32_t lineOrBytecode;
  Uint32Vector callSiteLineNums;

  FuncCompileInput(uint32_t index, uint32_t lineOrBytecode,
                   const uint8_t* begin, const uint8_t* end,
                   Uint32Vector&& callSiteLineNums)
      : begin(begin),
        end(end),
        index(index),
        lineOrBytecode(lineOrBytecode),
        callSiteLineNums(std::move(callSiteLineNums)) {}
};

typedef Vector<FuncCompileInput, 8, SystemAllocPolicy> FuncCompileInputVector;

void CraneliftFreeReusableData(void* ptr);

struct CraneliftReusableDataDtor {
  void operator()(void* ptr) { CraneliftFreeReusableData(ptr); }
};

using CraneliftReusableData =
    mozilla::UniquePtr<void*, CraneliftReusableDataDtor>;

// CompiledCode contains the resulting code and metadata for a set of compiled
// input functions or stubs.

struct CompiledCode {
  Bytes bytes;
  CodeRangeVector codeRanges;
  CallSiteVector callSites;
  CallSiteTargetVector callSiteTargets;
  TrapSiteVectorArray trapSites;
  SymbolicAccessVector symbolicAccesses;
  jit::CodeLabelVector codeLabels;
  StackMaps stackMaps;
  CraneliftReusableData craneliftReusableData;

  MOZ_MUST_USE bool swap(jit::MacroAssembler& masm);
  MOZ_MUST_USE bool swapCranelift(jit::MacroAssembler& masm,
                                  CraneliftReusableData& craneliftData);

  void clear() {
    bytes.clear();
    codeRanges.clear();
    callSites.clear();
    callSiteTargets.clear();
    trapSites.clear();
    symbolicAccesses.clear();
    codeLabels.clear();
    stackMaps.clear();
    // The cranelift reusable data resets itself lazily.
    MOZ_ASSERT(empty());
  }

  bool empty() {
    return bytes.empty() && codeRanges.empty() && callSites.empty() &&
           callSiteTargets.empty() && trapSites.empty() &&
           symbolicAccesses.empty() && codeLabels.empty() && stackMaps.empty();
  }

  size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
};

// The CompileTaskState of a ModuleGenerator contains the mutable state shared
// between helper threads executing CompileTasks. Each CompileTask started on a
// helper thread eventually either ends up in the 'finished' list or increments
// 'numFailed'.

struct CompileTaskState {
  CompileTaskPtrVector finished;
  uint32_t numFailed;
  UniqueChars errorMessage;

  CompileTaskState() : numFailed(0) {}
  ~CompileTaskState() {
    MOZ_ASSERT(finished.empty());
    MOZ_ASSERT(!numFailed);
  }
};

using ExclusiveCompileTaskState = ExclusiveWaitableData<CompileTaskState>;

// A CompileTask holds a batch of input functions that are to be compiled on a
// helper thread as well as, eventually, the results of compilation.

struct CompileTask : public RunnableTask {
  const ModuleEnvironment& env;
  ExclusiveCompileTaskState& state;
  LifoAlloc lifo;
  FuncCompileInputVector inputs;
  CompiledCode output;

  CompileTask(const ModuleEnvironment& env, ExclusiveCompileTaskState& state,
              size_t defaultChunkSize)
      : env(env), state(state), lifo(defaultChunkSize) {}

  virtual ~CompileTask() = default;

  size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const;

  void runTask() override;
  ThreadType threadType() override { return ThreadType::THREAD_TYPE_WASM; }
};

// A ModuleGenerator encapsulates the creation of a wasm module. During the
// lifetime of a ModuleGenerator, a sequence of FunctionGenerators are created
// and destroyed to compile the individual function bodies. After generating all
// functions, ModuleGenerator::finish() must be called to complete the
// compilation and extract the resulting wasm module.

class MOZ_STACK_CLASS ModuleGenerator {
  typedef Vector<CompileTask, 0, SystemAllocPolicy> CompileTaskVector;
  typedef Vector<jit::CodeOffset, 0, SystemAllocPolicy> CodeOffsetVector;
  struct CallFarJump {
    uint32_t funcIndex;
    jit::CodeOffset jump;
    CallFarJump(uint32_t fi, jit::CodeOffset j) : funcIndex(fi), jump(j) {}
  };
  typedef Vector<CallFarJump, 0, SystemAllocPolicy> CallFarJumpVector;

  // Constant parameters
  SharedCompileArgs const compileArgs_;
  UniqueChars* const error_;
  const Atomic<bool>* const cancelled_;
  ModuleEnvironment* const env_;

  // Data that is moved into the result of finish()
  UniqueLinkData linkData_;
  UniqueMetadataTier metadataTier_;
  MutableMetadata metadata_;

  // Data scoped to the ModuleGenerator's lifetime
  ExclusiveCompileTaskState taskState_;
  LifoAlloc lifo_;
  jit::JitContext jcx_;
  jit::TempAllocator masmAlloc_;
  jit::WasmMacroAssembler masm_;
  Uint32Vector funcToCodeRange_;
  uint32_t debugTrapCodeOffset_;
  CallFarJumpVector callFarJumps_;
  CallSiteTargetVector callSiteTargets_;
  uint32_t lastPatchedCallSite_;
  uint32_t startOfUnpatchedCallsites_;
  CodeOffsetVector debugTrapFarJumps_;

  // Parallel compilation
  bool parallel_;
  uint32_t outstanding_;
  CompileTaskVector tasks_;
  CompileTaskPtrVector freeTasks_;
  CompileTask* currentTask_;
  uint32_t batchedBytecode_;

  // Assertions
  DebugOnly<bool> finishedFuncDefs_;

  bool allocateGlobalBytes(uint32_t bytes, uint32_t align,
                           uint32_t* globalDataOff);

  bool funcIsCompiled(uint32_t funcIndex) const;
  const CodeRange& funcCodeRange(uint32_t funcIndex) const;
  bool linkCallSites();
  void noteCodeRange(uint32_t codeRangeIndex, const CodeRange& codeRange);
  bool linkCompiledCode(CompiledCode& code);
  bool locallyCompileCurrentTask();
  bool finishTask(CompileTask* task);
  bool launchBatchCompile();
  bool finishOutstandingTask();
  bool finishCodegen();
  bool finishMetadataTier();
  UniqueCodeTier finishCodeTier();
  SharedMetadata finishMetadata(const Bytes& bytecode);

  bool isAsmJS() const { return env_->isAsmJS(); }
  Tier tier() const { return env_->tier(); }
  CompileMode mode() const { return env_->mode(); }
  bool debugEnabled() const { return env_->debugEnabled(); }

 public:
  ModuleGenerator(const CompileArgs& args, ModuleEnvironment* env,
                  const Atomic<bool>* cancelled, UniqueChars* error);
  ~ModuleGenerator();
  MOZ_MUST_USE bool init(Metadata* maybeAsmJSMetadata = nullptr);

  // Before finishFuncDefs() is called, compileFuncDef() must be called once
  // for each funcIndex in the range [0, env->numFuncDefs()).

  MOZ_MUST_USE bool compileFuncDef(
      uint32_t funcIndex, uint32_t lineOrBytecode, const uint8_t* begin,
      const uint8_t* end, Uint32Vector&& callSiteLineNums = Uint32Vector());

  // Must be called after the last compileFuncDef() and before finishModule()
  // or finishTier2().

  MOZ_MUST_USE bool finishFuncDefs();

  // If env->mode is Once or Tier1, finishModule() must be called to generate
  // a new Module. Otherwise, if env->mode is Tier2, finishTier2() must be
  // called to augment the given Module with tier 2 code.

  SharedModule finishModule(
      const ShareableBytes& bytecode,
      JS::OptimizedEncodingListener* maybeTier2Listener = nullptr);
  MOZ_MUST_USE bool finishTier2(const Module& module);
};

}  // namespace wasm
}  // namespace js

#endif  // wasm_generator_h