[inspector] Introduce translation of wasm frames

src/inspector/wasm-translation.cc

+// Copyright 2016 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/inspector/wasm-translation.h"
+
+#include <algorithm>
+
+#include "src/debug/debug-interface.h"
+#include "src/inspector/protocol/Debugger.h"
+#include "src/inspector/script-breakpoint.h"
+#include "src/inspector/string-util.h"
+#include "src/inspector/v8-debugger-agent-impl.h"
+#include "src/inspector/v8-debugger-script.h"
+
+using namespace v8_inspector;
+using namespace v8;
+
+namespace {
+int GetScriptId(Isolate *isolate, Local<Object> script_wrapper) {
+  Local<Value> script_id = script_wrapper
+                               ->Get(isolate->GetCurrentContext(),
+                                     toV8StringInternalized(isolate, "id"))
+                               .ToLocalChecked();
+  DCHECK(script_id->IsInt32());
+  return script_id->Int32Value(isolate->GetCurrentContext()).FromJust();
+}
+
+String16 GetScriptName(Isolate *isolate, Local<Object> script_wrapper) {
+  Local<Value> script_name = script_wrapper
+                                 ->Get(isolate->GetCurrentContext(),
+                                       toV8StringInternalized(isolate, "name"))
+                                 .ToLocalChecked();
+  DCHECK(script_name->IsString());
+  return toProtocolString(script_name.As<String>());
+}
+
+}  // namespace
+
+class WasmTranslation::TranslatorImpl {
+ public:
+  struct TransLocation {
+    v8::Isolate *isolate;
+    WasmTranslation *translation;
+    String16 script_id;
+    int line;
+    int column;
+    TransLocation(v8::Isolate *isolate, WasmTranslation *translation,
+                  String16 script_id, int line, int column)
+        : isolate(isolate),
+          translation(translation),
+          script_id(script_id),
+          line(line),
+          column(column) {}
+  };
+
+  virtual void Translate(TransLocation *loc) = 0;
+  virtual void TranslateBack(TransLocation *loc) = 0;
+
+  class RawTranslator;
+  class DisassemblingTranslator;
+};
+
+class WasmTranslation::TranslatorImpl::RawTranslator
+    : public WasmTranslation::TranslatorImpl {
+ public:
+  void Translate(TransLocation *loc) {}
+  void TranslateBack(TransLocation *loc) {}
+};
+
+class WasmTranslation::TranslatorImpl::DisassemblingTranslator
+    : public WasmTranslation::TranslatorImpl {
+  using OffsetTable = std::vector<std::tuple<uint32_t, int, int>>;
+
+ public:
+  DisassemblingTranslator(Isolate *isolate, Local<Object> script)
+      : script_(isolate, script) {}
+
+  void Translate(TransLocation *loc) {
+    const OffsetTable &offset_table = GetOffsetTable(loc);
+    DCHECK(!offset_table.empty());
+    uint32_t byte_offset = static_cast<uint32_t>(loc->column);
+
+    // Binary search for the given offset.
+    unsigned left = 0;                                            // inclusive
+    unsigned right = static_cast<unsigned>(offset_table.size());  // exclusive
+    while (right - left > 1) {
+      unsigned mid = (left + right) / 2;
+      if (std::get<0>(offset_table[mid]) <= byte_offset) {
+        left = mid;
+      } else {
+        right = mid;
+      }
+    }
+
+    loc->script_id = GetFakeScriptId(loc);
+    if (std::get<0>(offset_table[left]) == byte_offset) {
+      loc->line = std::get<1>(offset_table[left]);
+      loc->column = std::get<2>(offset_table[left]);
+    } else {
+      loc->line = 0;
+      loc->column = 0;
+    }
+  }
+
+  void TranslateBack(TransLocation *loc) {
+    int func_index = GetFunctionIndexFromFakeScriptId(loc->script_id);
+    const OffsetTable *reverse_table = GetReverseTable(func_index);
+    if (!reverse_table) return;
+    DCHECK(!reverse_table->empty());
+
+    // Binary search for the given line and column.
+    unsigned left = 0;                                              // inclusive
+    unsigned right = static_cast<unsigned>(reverse_table->size());  // exclusive
+    while (right - left > 1) {
+      unsigned mid = (left + right) / 2;
+      auto &entry = (*reverse_table)[mid];
+      if (std::get<1>(entry) < loc->line ||
+          (std::get<1>(entry) == loc->line &&
+           std::get<2>(entry) <= loc->column)) {
+        left = mid;
+      } else {
+        right = mid;
+      }
+    }
+
+    int found_byte_offset = 0;
+    // If we found an exact match, use it. Otherwise check whether the next
+    // bigger entry is still in the same line. Report that one then.
+    if (std::get<1>((*reverse_table)[left]) == loc->line &&
+        std::get<2>((*reverse_table)[left]) == loc->column) {
+      found_byte_offset = std::get<0>((*reverse_table)[left]);
+    } else if (left + 1 < reverse_table->size() &&
+               std::get<1>((*reverse_table)[left + 1]) == loc->line) {
+      found_byte_offset = std::get<0>((*reverse_table)[left + 1]);
+    }
+
+    loc->script_id = String16::fromInteger(
+        GetScriptId(loc->isolate, script_.Get(loc->isolate)));
+    loc->line = func_index;
+    loc->column = found_byte_offset;
+  }
+
+ private:
+  String16 GetFakeScriptUrl(const TransLocation *loc) {
+    String16 script_name =
+        GetScriptName(loc->isolate, script_.Get(loc->isolate));
+    return String16::concat("wasm://wasm/", script_name, '/', script_name, '-',
+                            String16::fromInteger(loc->line));
+  }
+
+  String16 GetFakeScriptId(const TransLocation *loc) {
+    return String16::concat(loc->script_id, '-',
+                            String16::fromInteger(loc->line));
+  }
+
+  int GetFunctionIndexFromFakeScriptId(const String16 &fake_script_id) {
+    size_t last_dash_pos = fake_script_id.reverseFind('-');
+    DCHECK_GT(fake_script_id.length(), last_dash_pos);
+    bool ok = true;
+    int func_index = fake_script_id.substring(last_dash_pos + 1).toInteger(&ok);
+    DCHECK(ok);
+    return func_index;
+  }
+
+  const OffsetTable &GetOffsetTable(const TransLocation *loc) {
+    int func_index = loc->line;
+    auto it = offset_tables_.find(func_index);
+    if (it != offset_tables_.end()) return it->second;
+
+    std::pair<std::string, OffsetTable> disassembly =
+        DebugInterface::DisassembleWasmFunction(
+            loc->isolate, script_.Get(loc->isolate), func_index);
+
+    it = offset_tables_
+             .insert(std::make_pair(func_index, std::move(disassembly.second)))
+             .first;
+
+    String16 fake_script_id = GetFakeScriptId(loc);
+    String16 fake_script_url = GetFakeScriptUrl(loc);
+    String16 source(disassembly.first.data(), disassembly.first.length());
+    std::unique_ptr<V8DebuggerScript> fake_script(new V8DebuggerScript(
+        fake_script_id, std::move(fake_script_url), source));
+
+    loc->translation->AddFakeScript(std::move(fake_script), this);
+
+    return it->second;
+  }
+
+  const OffsetTable *GetReverseTable(int func_index) {
+    auto it = reverse_tables_.find(func_index);
+    if (it != reverse_tables_.end()) return &it->second;
+
+    // Find offset table, copy and sort it to get reverse table.
+    it = offset_tables_.find(func_index);
+    if (it == offset_tables_.end()) return nullptr;
+
+    OffsetTable reverse_table = it->second;
+    // Order by line, column, then byte offset.
+    auto cmp = [](std::tuple<uint32_t, int, int> el1,
+                  std::tuple<uint32_t, int, int> el2) {
+      if (std::get<1>(el1) != std::get<1>(el2))
+        return std::get<1>(el1) < std::get<1>(el2);
+      if (std::get<2>(el1) != std::get<2>(el2))
+        return std::get<2>(el1) < std::get<2>(el2);
+      return std::get<0>(el1) < std::get<0>(el2);
+    };
+    std::sort(reverse_table.begin(), reverse_table.end(), cmp);
+
+    auto inserted = reverse_tables_.insert(
+        std::make_pair(func_index, std::move(reverse_table)));
+    DCHECK(inserted.second);
+    return &inserted.first->second;
+  }
+
+  Global<Object> script_;
+
+  // We assume to only disassemble a subset of the functions, so store them in a
+  // map instead of an array.
+  std::unordered_map<int, const OffsetTable> offset_tables_;
+  std::unordered_map<int, const OffsetTable> reverse_tables_;
+};
+
+WasmTranslation::WasmTranslation(Isolate *isolate,
+                                 V8DebuggerAgentImpl *debugger_agent)
+    : isolate_(isolate), debugger_agent_(debugger_agent), mode_(Disassemble) {}
+
+WasmTranslation::~WasmTranslation() { Clear(); }
+
+void WasmTranslation::AddScript(Local<Object> script_wrapper) {
+  int script_id = GetScriptId(isolate_, script_wrapper);
+  DCHECK_EQ(0U, wasm_translators_.count(script_id));
+  std::unique_ptr<TranslatorImpl> impl;
+  switch (mode_) {
+    case Raw:
+      impl.reset(new TranslatorImpl::RawTranslator());
+      break;
+    case Disassemble:
+      impl.reset(new TranslatorImpl::DisassemblingTranslator(isolate_,
+                                                             script_wrapper));
+      break;
+  }
+  DCHECK(impl);
+  wasm_translators_.insert(std::make_pair(script_id, std::move(impl)));
+}
+
+void WasmTranslation::Clear() {
+  wasm_translators_.clear();
+  fake_scripts_.clear();
+}
+
+bool WasmTranslation::Translate(protocol::Debugger::Location *location) {
+  // Line and column in protocol Location are 0-based.
+  String16 script_id = location->getScriptId();
+  int line_number = location->getLineNumber();
+  int column_number = location->getColumnNumber(-1);
+
+  if (column_number < 0 || !Translate(&script_id, &line_number, &column_number))
+    return false;
+
+  location->setScriptId(std::move(script_id));
+  location->setLineNumber(line_number);
+  location->setColumnNumber(column_number);
+
+  return true;
+}
+
+bool WasmTranslation::Translate(String16 *script_id, int *line_number,
+                                int *column_number) {
+  DCHECK(script_id && line_number && column_number);
+  bool ok = true;
+  int script_id_int = script_id->toInteger(&ok);
+  if (!ok) return false;
+
+  auto it = wasm_translators_.find(script_id_int);
+  if (it == wasm_translators_.end()) return false;
+  TranslatorImpl *translator = it->second.get();
+
+  TranslatorImpl::TransLocation trans_loc(isolate_, this, std::move(*script_id),
+                                          *line_number, *column_number);
+  translator->Translate(&trans_loc);
+
+  *script_id = std::move(trans_loc.script_id);
+  *line_number = trans_loc.line;
+  *column_number = trans_loc.column;
+
+  return true;
+}
+
+bool WasmTranslation::TranslateBack(ScriptBreakpoint *breakpoint) {
+  auto it = fake_scripts_.find(breakpoint->script_id);
+  if (it == fake_scripts_.end()) return false;
+  TranslatorImpl *translator = it->second;
+
+  TranslatorImpl::TransLocation trans_loc(
+      isolate_, this, std::move(breakpoint->script_id), breakpoint->line_number,
+      breakpoint->column_number);
+  translator->TranslateBack(&trans_loc);
+
+  breakpoint->script_id = std::move(trans_loc.script_id);
+  breakpoint->line_number = trans_loc.line;
+  breakpoint->column_number = trans_loc.column;
+
+  return true;
+}
+
+void WasmTranslation::AddFakeScript(
+    std::unique_ptr<V8DebuggerScript> fake_script, TranslatorImpl *translator) {
+  bool inserted =
+      fake_scripts_.insert(std::make_pair(fake_script->scriptId(), translator))
+          .second;
+  DCHECK(inserted);
+  USE(inserted);
+  debugger_agent_->didParseSource(std::move(fake_script), true);
+}