[log] Add more fine-grained logging flags

New Flags added:
--log-source-code
--log-source-position
--log-feedback-vector

With the above flags we can choose between detailed or lightweight
logging.

Drive-by-fix:
- Use std::isprint
- Add AppendRawString to avoid vprintf formatting for raw strings


Change-Id: I3e9eda8473153de9620d24617c5a5e12e2e3bd56
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3863469
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Jakob Linke <jgruber@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82897}

src/flags/flag-definitions.h

@@ -2069,12 +2069,16 @@ DEFINE_BOOL(log, false,
             "Minimal logging (no API, code, GC, suspect, or handles samples).")
 DEFINE_BOOL(log_all, false, "Log all events to the log file.")
 
+DEFINE_BOOL(log_source_code, false, "Log source code.")
+DEFINE_BOOL(log_source_position, false, "Log detailed source information.")
 DEFINE_BOOL(log_code, false,
             "Log code events to the log file without profiling.")
+DEFINE_WEAK_IMPLICATION(log_code, log_source_code)
+DEFINE_WEAK_IMPLICATION(log_code, log_source_position)
+DEFINE_BOOL(log_feedback_vector, false, "Log FeedbackVectors on first creation")
 DEFINE_BOOL(log_code_disassemble, false,
             "Log all disassembled code to the log file.")
 DEFINE_IMPLICATION(log_code_disassemble, log_code)
-DEFINE_BOOL(log_source_code, false, "Log source code.")
 DEFINE_BOOL(log_function_events, false,
             "Log function events "
             "(parse, compile, execute) separately.")

src/init/v8.cc

@@ -129,6 +129,8 @@ void V8::Initialize() {
                                       &FLAG_log_code,
                                       &FLAG_log_code_disassemble,
                                       &FLAG_log_source_code,
+                                      &FLAG_log_source_position,
+                                      &FLAG_log_feedback_vector,
                                       &FLAG_log_function_events,
                                       &FLAG_log_internal_timer_events,
                                       &FLAG_log_deopt,

src/logging/log-file.cc

@@ -171,19 +171,19 @@ void LogFile::MessageBuilder::AppendTwoByteCharacter(char c1, char c2) {
   }
 }
 void LogFile::MessageBuilder::AppendCharacter(char c) {
-  if (c >= 32 && c <= 126) {
+  if (std::isprint(c)) {
     if (c == ',') {
       // Escape commas to avoid adding column separators.
-      AppendRawFormatString("\\x2C");
+      AppendRawString("\\x2C");
     } else if (c == '\\') {
-      AppendRawFormatString("\\\\");
+      AppendRawString("\\\\");
     } else {
       // Safe, printable ascii character.
       AppendRawCharacter(c);
     }
   } else if (c == '\n') {
     // Escape newlines to avoid adding row separators.
-    AppendRawFormatString("\\n");
+    AppendRawString("\\n");
   } else {
     // Escape non-printable characters.
     AppendRawFormatString("\\x%02x", c & 0xFF);
@@ -242,6 +242,10 @@ void LogFile::MessageBuilder::AppendRawFormatString(const char* format, ...) {
   }
 }
 
+void LogFile::MessageBuilder::AppendRawString(const char* str) {
+  log_->os_ << str;
+}
+
 void LogFile::MessageBuilder::AppendRawCharacter(char c) { log_->os_ << c; }
 
 void LogFile::MessageBuilder::WriteToLogFile() { log_->os_ << std::endl; }

src/logging/log-file.h

@@ -95,6 +95,7 @@ class LogFile {
     void AppendSymbolNameDetails(String str, bool show_impl_info);
 
     void PRINTF_FORMAT(2, 3) AppendRawFormatString(const char* format, ...);
+    void AppendRawString(const char* format);
     void AppendRawCharacter(const char character);
 
     LogFile* log_;

src/logging/log.cc

@@ -1287,6 +1287,7 @@ void V8FileLogger::LogSourceCodeInformation(Handle<AbstractCode> code,
   Script script = Script::cast(script_object);
   EnsureLogScriptSource(script);
 
+  if (!FLAG_log_source_position) return;
   MSG_BUILDER();
   msg << "code-source-info" << V8FileLogger::kNext
       << reinterpret_cast<void*>(code->InstructionStart(cage_base))
@@ -1425,7 +1426,7 @@ void V8FileLogger::CodeCreateEvent(CodeTag tag, Handle<AbstractCode> code,
 void V8FileLogger::FeedbackVectorEvent(FeedbackVector vector,
                                        AbstractCode code) {
   DisallowGarbageCollection no_gc;
-  if (!FLAG_log_code) return;
+  if (!FLAG_log_feedback_vector) return;
   PtrComprCageBase cage_base(isolate_);
   MSG_BUILDER();
   msg << "feedback-vector" << kNext << Time();
@@ -1755,6 +1756,7 @@ void V8FileLogger::ScriptDetails(Script script) {
 }
 
 bool V8FileLogger::EnsureLogScriptSource(Script script) {
+  if (!FLAG_log_source_code) return true;
   // Make sure the script is written to the log file.
   int script_id = script.id();
   if (logged_source_code_.find(script_id) != logged_source_code_.end()) {