Use size_t for Vector<T> size.

Conf. c++ coding guide (https://chromium.googlesource.com/chromium/src/+/master/styleguide/c++/c++.md#Types),
we may use size_t for vector indices, etc.

Bug: 
Change-Id: I578fb4199c061b006d03e1cc68e745868b40c227
Reviewed-on: https://chromium-review.googlesource.com/503590
Commit-Queue: Mircea Trofin <mtrofin@chromium.org>
Reviewed-by: Brad Nelson <bradnelson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45267}

src/api.cc

@@ -7667,8 +7667,7 @@ MaybeLocal<WasmCompiledModule> WasmCompiledModule::Deserialize(
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   i::MaybeHandle<i::FixedArray> maybe_compiled_part =
       i::WasmCompiledModuleSerializer::DeserializeWasmModule(
-          i_isolate, &sc,
-          {wire_bytes.first, static_cast<int>(wire_bytes.second)});
+          i_isolate, &sc, {wire_bytes.first, wire_bytes.second});
   i::Handle<i::FixedArray> compiled_part;
   if (!maybe_compiled_part.ToHandle(&compiled_part)) {
     return MaybeLocal<WasmCompiledModule>();

src/compiler/wasm-compiler.cc

@@ -3816,16 +3816,17 @@ Handle<Code> CompileWasmToJSWrapper(Isolate* isolate, Handle<JSReceiver> target,
   }
   if (isolate->logger()->is_logging_code_events() || isolate->is_profiling()) {
     const char* function_name = nullptr;
-    int function_name_size = 0;
+    size_t function_name_size = 0;
     if (!import_name.is_null()) {
       Handle<String> handle = import_name.ToHandleChecked();
       function_name = handle->ToCString().get();
-      function_name_size = handle->length();
+      function_name_size = static_cast<size_t>(handle->length());
     }
-    RecordFunctionCompilation(
-        CodeEventListener::FUNCTION_TAG, isolate, code, "wasm-to-js", index,
-        {module_name->ToCString().get(), module_name->length()},
-        {function_name, function_name_size});
+    RecordFunctionCompilation(CodeEventListener::FUNCTION_TAG, isolate, code,
+                              "wasm-to-js", index,
+                              {module_name->ToCString().get(),
+                               static_cast<size_t>(module_name->length())},
+                              {function_name, function_name_size});
   }
 
   return code;

src/vector.h

@@ -20,8 +20,9 @@ template <typename T>
 class Vector {
  public:
   Vector() : start_(NULL), length_(0) {}
-  Vector(T* data, int length) : start_(data), length_(length) {
-    DCHECK(length == 0 || (length > 0 && data != NULL));
+
+  Vector(T* data, size_t length) : start_(data), length_(length) {
+    DCHECK(length == 0 || data != NULL);
   }
 
   template <int N>
@@ -33,15 +34,20 @@ class Vector {
 
   // Returns a vector using the same backing storage as this one,
   // spanning from and including 'from', to but not including 'to'.
-  Vector<T> SubVector(int from, int to) const {
-    DCHECK_LE(0, from);
+  Vector<T> SubVector(size_t from, size_t to) const {
     DCHECK_LE(from, to);
     DCHECK_LE(to, length_);
     return Vector<T>(start() + from, to - from);
   }
 
   // Returns the length of the vector.
-  int length() const { return length_; }
+  int length() const {
+    DCHECK(length_ <= static_cast<size_t>(std::numeric_limits<int>::max()));
+    return static_cast<int>(length_);
+  }
+
+  // Returns the length of the vector as a size_t.
+  size_t size() const { return length_; }
 
   // Returns whether or not the vector is empty.
   bool is_empty() const { return length_ == 0; }
@@ -50,13 +56,12 @@ class Vector {
   T* start() const { return start_; }
 
   // Access individual vector elements - checks bounds in debug mode.
-  T& operator[](int index) const {
-    DCHECK_LE(0, index);
+  T& operator[](size_t index) const {
     DCHECK_LT(index, length_);
     return start_[index];
   }
 
-  const T& at(int index) const { return operator[](index); }
+  const T& at(size_t index) const { return operator[](index); }
 
   T& first() { return start_[0]; }
 
@@ -69,7 +74,7 @@ class Vector {
   // Returns a clone of this vector with a new backing store.
   Vector<T> Clone() const {
     T* result = NewArray<T>(length_);
-    for (int i = 0; i < length_; i++) result[i] = start_[i];
+    for (size_t i = 0; i < length_; i++) result[i] = start_[i];
     return Vector<T>(result, length_);
   }
 
@@ -101,7 +106,7 @@ class Vector {
 
   void StableSort() { std::stable_sort(start(), start() + length()); }
 
-  void Truncate(int length) {
+  void Truncate(size_t length) {
     DCHECK(length <= length_);
     length_ = length;
   }
@@ -114,8 +119,8 @@ class Vector {
     length_ = 0;
   }
 
-  inline Vector<T> operator+(int offset) {
-    DCHECK(offset < length_);
+  inline Vector<T> operator+(size_t offset) {
+    DCHECK_LT(offset, length_);
     return Vector<T>(start_ + offset, length_ - offset);
   }
 
@@ -134,7 +139,7 @@ class Vector {
   bool operator==(const Vector<T>& other) const {
     if (length_ != other.length_) return false;
     if (start_ == other.start_) return true;
-    for (int i = 0; i < length_; ++i) {
+    for (size_t i = 0; i < length_; ++i) {
       if (start_[i] != other.start_[i]) {
         return false;
       }
@@ -147,7 +152,7 @@ class Vector {
 
  private:
   T* start_;
-  int length_;
+  size_t length_;
 
   template <typename CookedComparer>
   class RawComparer {

src/wasm/wasm-module.cc

@@ -144,8 +144,8 @@ Handle<Script> CreateWasmScript(Isolate* isolate,
   script->set_type(Script::TYPE_WASM);
 
   int hash = StringHasher::HashSequentialString(
-      reinterpret_cast<const char*>(wire_bytes.start()), wire_bytes.length(),
-      kZeroHashSeed);
+      reinterpret_cast<const char*>(wire_bytes.start()),
+      static_cast<int>(wire_bytes.length()), kZeroHashSeed);
 
   const int kBufferSize = 32;
   char buffer[kBufferSize];
@@ -2619,7 +2619,7 @@ class AsyncCompileJob {
   // finished.
  public:
   explicit AsyncCompileJob(Isolate* isolate, std::unique_ptr<byte[]> bytes_copy,
-                           int length, Handle<Context> context,
+                           size_t length, Handle<Context> context,
                            Handle<JSPromise> promise)
       : isolate_(isolate),
         bytes_copy_(std::move(bytes_copy)),

src/wasm/wasm-module.h

@@ -294,7 +294,7 @@ struct V8_EXPORT_PRIVATE ModuleWireBytes {
 
   const byte* start() const { return module_bytes_.start(); }
   const byte* end() const { return module_bytes_.end(); }
-  int length() const { return module_bytes_.length(); }
+  size_t length() const { return module_bytes_.length(); }
 
  private:
   const Vector<const byte> module_bytes_;