improve perf_basic_prof filename reporting

Re-implement https://codereview.chromium.org/1388543002 after fixing the issue
with SNPrintF crashing on windows when a zero-length buffer is passed in.

R=jkummerow@chromium.org,yangguo@chromium.org,yurys@chromium.org
BUG=chromium:539892
LOG=N

Review URL: https://codereview.chromium.org/1396843004

Cr-Commit-Position: refs/heads/master@{#31197}

src/log.cc

@@ -123,8 +123,9 @@ 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;
@@ -132,8 +133,9 @@ class CodeEventLogger::NameBuffer {
   }
 
   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;
@@ -145,7 +147,7 @@ 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];

test/cctest/test-log.cc

@@ -531,3 +531,50 @@ TEST(LogVersion) {
   }
   isolate->Dispose();
 }
+
+
+// https://crbug.com/539892
+// CodeCreateEvents with really large names should not crash.
+TEST(Issue539892) {
+  SETUP_FLAGS();
+  bool saved_perf_basic_prof = i::FLAG_perf_basic_prof;
+  i::FLAG_perf_basic_prof = true;
+
+  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();
+
+    // 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();
+  i::FLAG_perf_basic_prof = saved_perf_basic_prof;
+}