[inspector] extend protocol for code coverage.

src/debug/debug-coverage.cc

 // Copyright 2017 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/debug/debug-coverage.h"
 
 #include "src/base/hashmap.h"
 #include "src/deoptimizer.h"
 #include "src/isolate.h"
 #include "src/objects-inl.h"
@@ skipping 40 matching lines @@
 }
 
 bool CompareSharedFunctionInfo(SharedFunctionInfo* a, SharedFunctionInfo* b) {
   int a_start = StartPosition(a);
   int b_start = StartPosition(b);
   if (a_start == b_start) return a->end_position() > b->end_position();
   return a_start < b_start;
 }
 }  // anonymous namespace
 
-CoverageScript::CoverageScript(Isolate* isolate, Handle<Script> s,
-                               int source_length)
-    : script(s),
-      toplevel(0, source_length, 1, isolate->factory()->empty_string()) {}
-
-Coverage* Coverage::Collect(Isolate* isolate) {
+Coverage* Coverage::Collect(Isolate* isolate, bool reset_count) {
   SharedToCounterMap counter_map;
 
   // Feed invocation count into the counter map.
   if (isolate->IsCodeCoverageEnabled()) {
     // Feedback vectors are already listed to prevent losing them to GC.
     Handle<ArrayList> list =
         Handle<ArrayList>::cast(isolate->factory()->code_coverage_list());
     for (int i = 0; i < list->Length(); i++) {
       FeedbackVector* vector = FeedbackVector::cast(list->Get(i));
       SharedFunctionInfo* shared = vector->shared_function_info();
       DCHECK(shared->IsSubjectToDebugging());
       uint32_t count = static_cast<uint32_t>(vector->invocation_count());
+      if (reset_count) vector->clear_invocation_count();
       counter_map.Add(shared, count);
     }
   } else {
     // Iterate the heap to find all feedback vectors and accumulate the
     // invocation counts into the map for each shared function info.
     HeapIterator heap_iterator(isolate->heap());
     while (HeapObject* current_obj = heap_iterator.next()) {
       if (!current_obj->IsFeedbackVector()) continue;
       FeedbackVector* vector = FeedbackVector::cast(current_obj);
       SharedFunctionInfo* shared = vector->shared_function_info();
       if (!shared->IsSubjectToDebugging()) continue;
       uint32_t count = static_cast<uint32_t>(vector->invocation_count());
+      if (reset_count) vector->clear_invocation_count();
       counter_map.Add(shared, count);
     }
   }
 
   // Iterate shared function infos of every script and build a mapping
   // between source ranges and invocation counts.
   Coverage* result = new Coverage();
   Script::Iterator scripts(isolate);
   while (Script* script = scripts.Next()) {
     // Dismiss non-user scripts.
     if (script->type() != Script::TYPE_NORMAL) continue;
 
     // Create and add new script data.
-    int source_end = String::cast(script->source())->length();
     Handle<Script> script_handle(script, isolate);
-    result->emplace_back(isolate, script_handle, source_end);
+    result->emplace_back(isolate, script_handle);
+    std::vector<CoverageFunction>* functions = &result->back().functions;
 
     std::vector<SharedFunctionInfo*> sorted;
+    bool has_toplevel = false;
 
     {
-      // Collect a list of shared function infos sorted by start position.
-      // Shared function infos are usually already sorted. Except for classes.
-      // If the start position is the same, sort from outer to inner function.
+      // Sort functions by start position, from outer to inner functions.
       SharedFunctionInfo::ScriptIterator infos(script_handle);
-      while (SharedFunctionInfo* info = infos.Next()) sorted.push_back(info);
+      while (SharedFunctionInfo* info = infos.Next()) {
+        has_toplevel |= info->is_toplevel();
+        sorted.push_back(info);
+      }
       std::sort(sorted.begin(), sorted.end(), CompareSharedFunctionInfo);
     }
 
-    std::vector<CoverageRange*> stack;
-    stack.push_back(&result->back().toplevel);
+    functions->reserve(sorted.size() + (has_toplevel ? 0 : 1));
+
+    if (!has_toplevel) {
+      // Add a replacement toplevel function if it does not exist.
+      int source_end = String::cast(script->source())->length();
+      functions->emplace_back(0, source_end, 1u,
+                              isolate->factory()->empty_string());
+    }
 
     // Use sorted list to reconstruct function nesting.
     for (SharedFunctionInfo* info : sorted) {
       int start = StartPosition(info);
       int end = info->end_position();
       uint32_t count = counter_map.Get(info);
-      if (info->is_toplevel()) {
-        // Top-level function is available.
-        DCHECK_EQ(1, stack.size());
-        result->back().toplevel.start = start;
-        result->back().toplevel.end = end;
-        result->back().toplevel.count = count;
-      } else {
-        // The shared function infos are sorted by start.
-        DCHECK_LE(stack.back()->start, start);
-        // Drop the stack to the outer function.
-        while (start >= stack.back()->end) stack.pop_back();
-        CoverageRange* outer = stack.back();
-        // New nested function.
-        DCHECK_LE(end, outer->end);
-        Handle<String> name(info->DebugName(), isolate);
-        outer->inner.emplace_back(start, end, count, name);
-        stack.push_back(&outer->inner.back());
-      }
+      Handle<String> name(info->DebugName(), isolate);
+      functions->emplace_back(start, end, count, name);
     }
   }
   return result;
 }
 
 void Coverage::TogglePrecise(Isolate* isolate, bool enable) {
   if (enable) {
     HandleScope scope(isolate);
     // Remove all optimized function. Optimized and inlined functions do not
     // increment invocation count.
@@ skipping 16 matching lines @@
         ArrayList::New(isolate, static_cast<int>(vectors.size()));
     for (const auto& vector : vectors) list = ArrayList::Add(list, vector);
     isolate->SetCodeCoverageList(*list);
   } else {
     isolate->SetCodeCoverageList(isolate->heap()->undefined_value());
   }
 }
 
 }  // namespace internal
 }  // namespace v8