// Copyright 2019 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include 'src/builtins/builtins-regexp-gen.h'

namespace internal_coverage {

  const kHasCoverageInfo:
      constexpr int31 generates 'DebugInfo::kHasCoverageInfo';

  const kFirstSlotIndex:
      constexpr int31 generates 'CoverageInfo::kFirstSlotIndex';
  const kSlotBlockCountIndex:
      constexpr int31 generates 'CoverageInfo::kSlotBlockCountIndex';
  const kSlotIndexCountLog2:
      constexpr int31 generates 'CoverageInfo::kSlotIndexCountLog2';
  const kSlotIndexCountMask:
      constexpr int31 generates 'CoverageInfo::kSlotIndexCountMask';

  macro GetCoverageInfo(implicit context: Context)(function: JSFunction):
      CoverageInfo labels IfNoCoverageInfo {
    const shared: SharedFunctionInfo = function.shared_function_info;
    const debugInfo = Cast<DebugInfo>(shared.script_or_debug_info)
        otherwise goto IfNoCoverageInfo;

    if ((debugInfo.flags & kHasCoverageInfo) == 0) goto IfNoCoverageInfo;
    return UnsafeCast<CoverageInfo>(debugInfo.coverage_info);
  }

  @export  // Silence unused warning on release builds. SlotCount is only used
           // in an assert. TODO(szuend): Remove once macros and asserts work.
  macro SlotCount(coverageInfo: CoverageInfo): Smi {
    assert(kFirstSlotIndex == 0);  // Otherwise we'd have to consider it below.
    assert(kFirstSlotIndex == (coverageInfo.length & kSlotIndexCountMask));
    return coverageInfo.length >> kSlotIndexCountLog2;
  }

  macro FirstIndexForSlot(implicit context: Context)(slot: Smi): Smi {
    assert(kFirstSlotIndex == 0);  // Otherwise we'd have to consider it below.
    return slot << kSlotIndexCountLog2;
  }

  macro IncrementBlockCount(implicit context: Context)(
      coverageInfo: CoverageInfo, slot: Smi) {
    assert(slot < SlotCount(coverageInfo));
    const slotStart: Smi = FirstIndexForSlot(slot);
    const index: Smi = slotStart + kSlotBlockCountIndex;
    coverageInfo.objects[index] =
        UnsafeCast<Smi>(coverageInfo.objects[index]) + 1;
  }

  builtin IncBlockCounter(implicit context: Context)(
      function: JSFunction, coverageArraySlotIndex: Smi): Object {
    // It's quite possible that a function contains IncBlockCounter bytecodes,
    // but no coverage info exists. This happens e.g. by selecting the
    // best-effort coverage collection mode, which triggers deletion of all
    // coverage infos in order to avoid memory leaks.

    const coverageInfo: CoverageInfo =
        GetCoverageInfo(function) otherwise return Undefined;
    IncrementBlockCount(coverageInfo, coverageArraySlotIndex);
    return Undefined;
  }

}  // namespace internal_coverage