/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99:
 *
 * Copyright 2016 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_debug_h
#define wasm_debug_h

#include "js/HashTable.h"
#include "wasm/WasmModule.h"
#include "wasm/WasmTypes.h"

namespace js {

class Debugger;
class WasmBreakpoint;
class WasmBreakpointSite;
class WasmInstanceObject;

namespace wasm {

struct MetadataTier;

// The generated source location for the AST node/expression. The offset field
// refers an offset in an binary format file.

struct ExprLoc
{
    uint32_t lineno;
    uint32_t column;
    uint32_t offset;
    ExprLoc() : lineno(0), column(0), offset(0) {}
    ExprLoc(uint32_t lineno_, uint32_t column_, uint32_t offset_)
      : lineno(lineno_), column(column_), offset(offset_)
    {}
};

typedef HashMap<uint32_t, uint32_t, DefaultHasher<uint32_t>, SystemAllocPolicy> StepModeCounters;
typedef HashMap<uint32_t, WasmBreakpointSite*, DefaultHasher<uint32_t>, SystemAllocPolicy>
    WasmBreakpointSiteMap;

class DebugState
{
    const SharedCode         code_;
    const SharedModule       module_;
    bool                     binarySource_;

    // State maintained when debugging is enabled. In this case, the Code is
    // not actually shared, but is referenced uniquely by the instance that is
    // being debugged.

    bool                     enterFrameTrapsEnabled_;
    uint32_t                 enterAndLeaveFrameTrapsCounter_;
    WasmBreakpointSiteMap    breakpointSites_;
    StepModeCounters         stepModeCounters_;

    void toggleDebugTrap(uint32_t offset, bool enabled);

  public:
    DebugState(const Code& code, const Module& module, bool binarySource);

    const Bytes& bytecode() const { return module_->debugBytecode(); }
    bool binarySource() const { return binarySource_; }

    bool getLineOffsets(JSContext* cx, size_t lineno, Vector<uint32_t>* offsets);
    bool getAllColumnOffsets(JSContext* cx, Vector<ExprLoc>* offsets);
    bool getOffsetLocation(uint32_t offset, size_t* lineno, size_t* column);
    uint32_t totalSourceLines();

    // The Code can track enter/leave frame events. Any such event triggers
    // debug trap. The enter/leave frame events enabled or disabled across
    // all functions.

    void adjustEnterAndLeaveFrameTrapsState(JSContext* cx, bool enabled);
    void ensureEnterFrameTrapsState(JSContext* cx, bool enabled);
    bool enterFrameTrapsEnabled() const { return enterFrameTrapsEnabled_; }

    // When the Code is debugEnabled, individual breakpoints can be enabled or
    // disabled at instruction offsets.

    bool hasBreakpointTrapAtOffset(uint32_t offset);
    void toggleBreakpointTrap(JSRuntime* rt, uint32_t offset, bool enabled);
    WasmBreakpointSite* getOrCreateBreakpointSite(JSContext* cx, uint32_t offset);
    bool hasBreakpointSite(uint32_t offset);
    void destroyBreakpointSite(FreeOp* fop, uint32_t offset);
    bool clearBreakpointsIn(JSContext* cx, WasmInstanceObject* instance, js::Debugger* dbg, JSObject* handler);

    // When the Code is debug-enabled, single-stepping mode can be toggled on
    // the granularity of individual functions.

    bool stepModeEnabled(uint32_t funcIndex) const;
    bool incrementStepModeCount(JSContext* cx, uint32_t funcIndex);
    bool decrementStepModeCount(FreeOp* fop, uint32_t funcIndex);

    // Stack inspection helpers.

    bool debugGetLocalTypes(uint32_t funcIndex, ValTypeVector* locals, size_t* argsLength);
    ExprType debugGetResultType(uint32_t funcIndex);
    bool getGlobal(Instance& instance, uint32_t globalIndex, MutableHandleValue vp);

    // Debug URL helpers.

    bool getSourceMappingURL(JSContext* cx, MutableHandleString result) const;

    // Accessors for commonly used elements of linked structures.

    const MetadataTier& metadata(Tier t) const { return code_->metadata(t); }
    const Metadata& metadata() const { return code_->metadata(); }
    const CodeRangeVector& codeRanges(Tier t) const { return metadata(t).codeRanges; }
    const CallSiteVector& callSites(Tier t) const { return metadata(t).callSites; }

    uint32_t funcToCodeRangeIndex(uint32_t funcIndex) const {
        return metadata(Tier::Debug).funcToCodeRange[funcIndex];
    }

    // about:memory reporting:

    void addSizeOfMisc(MallocSizeOf mallocSizeOf,
                       Metadata::SeenSet* seenMetadata,
                       ShareableBytes::SeenSet* seenBytes,
                       Code::SeenSet* seenCode,
                       size_t* code,
                       size_t* data) const;
};

typedef UniquePtr<DebugState> UniqueDebugState;

} // namespace wasm
} // namespace js

#endif // wasm_debug_h
