[turbofan] Fix JSON escapes in --trace-turbo files.

This makes the character escaping in the graph visualizer less generic
but correct against the JSON spec. The spec has the following definition
for valid characters within a double quoted string:

char ::
  any-Unicode-character-except-"-or-\-or-control-character
  \"
  \\
  \/
  \b
  \f
  \n
  \r
  \t
  \u four-hex-digits

R=bmeurer@chromium.org

Review-Url: https://codereview.chromium.org/2421313002
Cr-Commit-Position: refs/heads/master@{#40364}

src/compiler/graph-visualizer.cc

@@ -81,33 +81,28 @@ static const char* SafeMnemonic(Node* node) {
   return node == nullptr ? "null" : node->op()->mnemonic();
 }
 
-#define DEAD_COLOR "#999999"
-
-class Escaped {
+class JSONEscaped {
  public:
-  explicit Escaped(const std::ostringstream& os,
-                   const char* escaped_chars = "<>|{}\\")
-      : str_(os.str()), escaped_chars_(escaped_chars) {}
-
-  friend std::ostream& operator<<(std::ostream& os, const Escaped& e) {
-    for (std::string::const_iterator i = e.str_.begin(); i != e.str_.end();
-         ++i) {
-      if (e.needs_escape(*i)) os << "\\";
-      os << *i;
-    }
+  explicit JSONEscaped(const std::ostringstream& os) : str_(os.str()) {}
+
+  friend std::ostream& operator<<(std::ostream& os, const JSONEscaped& e) {
+    for (char c : e.str_) PipeCharacter(os, c);
     return os;
   }
 
  private:
-  bool needs_escape(char ch) const {
-    for (size_t i = 0; i < strlen(escaped_chars_); ++i) {
-      if (ch == escaped_chars_[i]) return true;
-    }
-    return false;
+  static std::ostream& PipeCharacter(std::ostream& os, char c) {
+    if (c == '"') return os << "\\\"";
+    if (c == '\\') return os << "\\\\";
+    if (c == '\b') return os << "\\b";
+    if (c == '\f') return os << "\\f";
+    if (c == '\n') return os << "\\n";
+    if (c == '\r') return os << "\\r";
+    if (c == '\t') return os << "\\t";
+    return os << c;
   }
 
   const std::string str_;
-  const char* const escaped_chars_;
 };
 
 class JSONGraphNodeWriter {
@@ -135,11 +130,11 @@ class JSONGraphNodeWriter {
     node->op()->PrintTo(label, Operator::PrintVerbosity::kSilent);
     node->op()->PrintTo(title, Operator::PrintVerbosity::kVerbose);
     node->op()->PrintPropsTo(properties);
-    os_ << "{\"id\":" << SafeId(node) << ",\"label\":\""
-        << Escaped(label, "\"\\") << "\""
-        << ",\"title\":\"" << Escaped(title, "\"\\") << "\""
+    os_ << "{\"id\":" << SafeId(node) << ",\"label\":\"" << JSONEscaped(label)
+        << "\""
+        << ",\"title\":\"" << JSONEscaped(title) << "\""
         << ",\"live\": " << (live_.IsLive(node) ? "true" : "false")
-        << ",\"properties\":\"" << Escaped(properties, "\"\\") << "\"";
+        << ",\"properties\":\"" << JSONEscaped(properties) << "\"";
     IrOpcode::Value opcode = node->opcode();
     if (IrOpcode::IsPhiOpcode(opcode)) {
       os_ << ",\"rankInputs\":[0," << NodeProperties::FirstControlIndex(node)
@@ -171,7 +166,7 @@ class JSONGraphNodeWriter {
       Type* type = NodeProperties::GetType(node);
       std::ostringstream type_out;
       type->PrintTo(type_out);
-      os_ << ",\"type\":\"" << Escaped(type_out, "\"\\") << "\"";
+      os_ << ",\"type\":\"" << JSONEscaped(type_out) << "\"";
     }
     os_ << "}";
   }