Reland workaround for perf-basic-prof filename truncation issue

deps/v8/src/log.cc

@@ -125,17 +125,19 @@ class CodeEventLogger::NameBuffer {
   }
 
   void AppendInt(int n) {
-    Vector<char> buffer(utf8_buffer_ + utf8_pos_,
-                        kUtf8BufferSize - utf8_pos_);
+    int space = kUtf8BufferSize - utf8_pos_;
+    if (space <= 0) return;
+    Vector<char> buffer(utf8_buffer_ + utf8_pos_, space);
     int size = SNPrintF(buffer, "%d", n);
     if (size > 0 && utf8_pos_ + size <= kUtf8BufferSize) {
       utf8_pos_ += size;
     }
   }
 
   void AppendHex(uint32_t n) {
-    Vector<char> buffer(utf8_buffer_ + utf8_pos_,
-                        kUtf8BufferSize - utf8_pos_);
+    int space = kUtf8BufferSize - utf8_pos_;
+    if (space <= 0) return;
+    Vector<char> buffer(utf8_buffer_ + utf8_pos_, space);
     int size = SNPrintF(buffer, "%x", n);
     if (size > 0 && utf8_pos_ + size <= kUtf8BufferSize) {
       utf8_pos_ += size;
@@ -147,7 +149,7 @@ class CodeEventLogger::NameBuffer {
 
  private:
   static const int kUtf8BufferSize = 512;
-  static const int kUtf16BufferSize = 128;
+  static const int kUtf16BufferSize = kUtf8BufferSize;
 
   int utf8_pos_;
   char utf8_buffer_[kUtf8BufferSize];

deps/v8/test/cctest/test-log.cc

@@ -531,3 +531,58 @@ TEST(LogVersion) {
   }
   isolate->Dispose();
 }
+
+
+// https://crbug.com/539892
+// CodeCreateEvents with really large names should not crash.
+TEST(Issue539892) {
+  class : public i::CodeEventLogger {
+   public:
+    virtual void CodeMoveEvent(Address from, Address to) {}
+    virtual void CodeDeleteEvent(Address from) {}
+    virtual void CodeDisableOptEvent(i::Code* code,
+                                     i::SharedFunctionInfo* shared) {}
+
+   private:
+    virtual void LogRecordedBuffer(i::Code* code, i::SharedFunctionInfo* shared,
+                                   const char* name, int length) {}
+  } code_event_logger;
+  SETUP_FLAGS();
+  v8::Isolate::CreateParams create_params;
+  create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
+  v8::Isolate* isolate = v8::Isolate::New(create_params);
+
+  {
+    ScopedLoggerInitializer initialize_logger(saved_log, saved_prof, isolate);
+    Logger* logger = initialize_logger.logger();
+    logger->addCodeEventListener(&code_event_logger);
+
+    // Function with a really large name.
+    const char* source_text =
+        "(function "
+        "baaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaac"
+        "(){})();";
+
+    CompileRun(source_text);
+
+    // Must not crash.
+    logger->LogCompiledFunctions();
+  }
+  isolate->Dispose();
+}