[parser] Reduce excessive inlining.

The inlining does not seem to actually improve performance, and hence outlining makes the code a bit more readable.

Performance + binary size appear to be at least as good as with inlining. On gcc I get several 10kBs savings in binary size, but only ~100B on clang. In no case have I observed a performance regression.

R=marja@chromium.org
BUG=v8:3437

Review-Url: https://codereview.chromium.org/2611993002
Cr-Commit-Position: refs/heads/master@{#42276}

src/parsing/scanner.cc

@@ -26,6 +26,68 @@ Handle<String> Scanner::LiteralBuffer::Internalize(Isolate* isolate) const {
   return isolate->factory()->InternalizeTwoByteString(two_byte_literal());
 }
 
+int Scanner::LiteralBuffer::NewCapacity(int min_capacity) {
+  int capacity = Max(min_capacity, backing_store_.length());
+  int new_capacity = Min(capacity * kGrowthFactory, capacity + kMaxGrowth);
+  return new_capacity;
+}
+
+void Scanner::LiteralBuffer::ExpandBuffer() {
+  Vector<byte> new_store = Vector<byte>::New(NewCapacity(kInitialCapacity));
+  MemCopy(new_store.start(), backing_store_.start(), position_);
+  backing_store_.Dispose();
+  backing_store_ = new_store;
+}
+
+void Scanner::LiteralBuffer::ConvertToTwoByte() {
+  DCHECK(is_one_byte_);
+  Vector<byte> new_store;
+  int new_content_size = position_ * kUC16Size;
+  if (new_content_size >= backing_store_.length()) {
+    // Ensure room for all currently read code units as UC16 as well
+    // as the code unit about to be stored.
+    new_store = Vector<byte>::New(NewCapacity(new_content_size));
+  } else {
+    new_store = backing_store_;
+  }
+  uint8_t* src = backing_store_.start();
+  uint16_t* dst = reinterpret_cast<uint16_t*>(new_store.start());
+  for (int i = position_ - 1; i >= 0; i--) {
+    dst[i] = src[i];
+  }
+  if (new_store.start() != backing_store_.start()) {
+    backing_store_.Dispose();
+    backing_store_ = new_store;
+  }
+  position_ = new_content_size;
+  is_one_byte_ = false;
+}
+
+void Scanner::LiteralBuffer::AddCharSlow(uc32 code_unit) {
+  if (position_ >= backing_store_.length()) ExpandBuffer();
+  if (is_one_byte_) {
+    if (code_unit <= static_cast<uc32>(unibrow::Latin1::kMaxChar)) {
+      backing_store_[position_] = static_cast<byte>(code_unit);
+      position_ += kOneByteSize;
+      return;
+    }
+    ConvertToTwoByte();
+  }
+  if (code_unit <=
+      static_cast<uc32>(unibrow::Utf16::kMaxNonSurrogateCharCode)) {
+    *reinterpret_cast<uint16_t*>(&backing_store_[position_]) = code_unit;
+    position_ += kUC16Size;
+  } else {
+    *reinterpret_cast<uint16_t*>(&backing_store_[position_]) =
+        unibrow::Utf16::LeadSurrogate(code_unit);
+    position_ += kUC16Size;
+    if (position_ >= backing_store_.length()) ExpandBuffer();
+    *reinterpret_cast<uint16_t*>(&backing_store_[position_]) =
+        unibrow::Utf16::TrailSurrogate(code_unit);
+    position_ += kUC16Size;
+  }
+}
+
 // ----------------------------------------------------------------------------
 // Scanner::BookmarkScope
 

src/parsing/scanner.h

@@ -353,36 +353,16 @@ class Scanner {
     ~LiteralBuffer() { backing_store_.Dispose(); }
 
     INLINE(void AddChar(char code_unit)) {
-      if (position_ >= backing_store_.length()) ExpandBuffer();
-      DCHECK(is_one_byte_);
       DCHECK(IsValidAscii(code_unit));
-      backing_store_[position_] = static_cast<byte>(code_unit);
-      position_ += kOneByteSize;
-      return;
+      AddOneByteChar(static_cast<byte>(code_unit));
     }
 
     INLINE(void AddChar(uc32 code_unit)) {
-      if (position_ >= backing_store_.length()) ExpandBuffer();
-      if (is_one_byte_) {
-        if (code_unit <= static_cast<uc32>(unibrow::Latin1::kMaxChar)) {
-          backing_store_[position_] = static_cast<byte>(code_unit);
-          position_ += kOneByteSize;
-          return;
-        }
-        ConvertToTwoByte();
-      }
-      if (code_unit <=
-          static_cast<uc32>(unibrow::Utf16::kMaxNonSurrogateCharCode)) {
-        *reinterpret_cast<uint16_t*>(&backing_store_[position_]) = code_unit;
-        position_ += kUC16Size;
+      if (is_one_byte_ &&
+          code_unit <= static_cast<uc32>(unibrow::Latin1::kMaxChar)) {
+        AddOneByteChar(static_cast<byte>(code_unit));
       } else {
-        *reinterpret_cast<uint16_t*>(&backing_store_[position_]) =
-            unibrow::Utf16::LeadSurrogate(code_unit);
-        position_ += kUC16Size;
-        if (position_ >= backing_store_.length()) ExpandBuffer();
-        *reinterpret_cast<uint16_t*>(&backing_store_[position_]) =
-            unibrow::Utf16::TrailSurrogate(code_unit);
-        position_ += kUC16Size;
+        AddCharSlow(code_unit);
       }
     }
 
@@ -434,43 +414,18 @@ class Scanner {
       return iscntrl(code_unit) || isprint(code_unit);
     }
 
-    inline int NewCapacity(int min_capacity) {
-      int capacity = Max(min_capacity, backing_store_.length());
-      int new_capacity = Min(capacity * kGrowthFactory, capacity + kMaxGrowth);
-      return new_capacity;
-    }
-
-    void ExpandBuffer() {
-      Vector<byte> new_store = Vector<byte>::New(NewCapacity(kInitialCapacity));
-      MemCopy(new_store.start(), backing_store_.start(), position_);
-      backing_store_.Dispose();
-      backing_store_ = new_store;
-    }
-
-    void ConvertToTwoByte() {
+    INLINE(void AddOneByteChar(byte one_byte_char)) {
       DCHECK(is_one_byte_);
-      Vector<byte> new_store;
-      int new_content_size = position_ * kUC16Size;
-      if (new_content_size >= backing_store_.length()) {
-        // Ensure room for all currently read code units as UC16 as well
-        // as the code unit about to be stored.
-        new_store = Vector<byte>::New(NewCapacity(new_content_size));
-      } else {
-        new_store = backing_store_;
-      }
-      uint8_t* src = backing_store_.start();
-      uint16_t* dst = reinterpret_cast<uint16_t*>(new_store.start());
-      for (int i = position_ - 1; i >= 0; i--) {
-        dst[i] = src[i];
-      }
-      if (new_store.start() != backing_store_.start()) {
-        backing_store_.Dispose();
-        backing_store_ = new_store;
-      }
-      position_ = new_content_size;
-      is_one_byte_ = false;
+      if (position_ >= backing_store_.length()) ExpandBuffer();
+      backing_store_[position_] = one_byte_char;
+      position_ += kOneByteSize;
     }
 
+    void AddCharSlow(uc32 code_unit);
+    int NewCapacity(int min_capacity);
+    void ExpandBuffer();
+    void ConvertToTwoByte();
+
     bool is_one_byte_;
     int position_;
     Vector<byte> backing_store_;