8355638: Allow -Xlog:aot to be used as an alias for -Xlog:cds

src/hotspot/share/logging/logSelection.cpp

@@ -85,6 +85,9 @@ bool LogSelection::superset_of(const LogSelection& other) const {
   return true;
 }
 
+// quick-and-dirty -- to be refactored properly.
+int _cds_tag_specified = 0;
+
 static LogSelection parse_internal(char *str, outputStream* errstream) {
   // Parse the level, if specified
   LogLevelType level = LogLevel::Unspecified;
@@ -166,7 +169,34 @@ static LogSelection parse_internal(char *str, outputStream* errstream) {
     }
   }
 
-  return LogSelection(tags, wildcard, level);
+  LogSelection ls = LogSelection(tags, wildcard, level);
+  if (ls.tag_sets_selected() == 0) {
+    // Make "aot" an alias for "cds. E.g.,
+    // -Xlog:aot -> -Xlog:cds
+    // -Xlog:aot+class -> -Xlog:cds+class
+    if (tags[0] == LogTag::_aot) {
+      LogTagType aliased_tags[LogTag::MaxTags];
+      memcpy(aliased_tags, tags, sizeof(tags));
+      aliased_tags[0] = LogTag::_cds;
+      LogSelection aliased_ls = LogSelection(aliased_tags, wildcard, level);
+      if (aliased_ls.tag_sets_selected() > 0) {
+        return aliased_ls;
+      }
+    }
+  } else {
+    if (tags[0] == LogTag::_cds) {
+      // If the user has specified ONLY -Xlog:aot, then all "cds" logs will be printed with an "aot" decoration.
+      //
+      // [0.022s][info][aot] full module graph: enabled
+      // [2.335s][debug][aot,class] klasses[ 1587] = ...
+      //
+      // For backwards compatibility (until we convert all "cds" logs to "aot" logs, if
+      // the user has specifed at least one log of the "cds" type, then we will
+      // revert to the "cds" decoration.
+      _cds_tag_specified ++;
+    }
+  }
+  return ls;
 }
 
 LogSelection LogSelection::parse(const char* str, outputStream* error_stream) {

src/hotspot/share/logging/logSelectionList.cpp

@@ -28,6 +28,8 @@
 
 static const char* DefaultExpressionString = "all";
 
+extern int _cds_tag_specified;
+
 bool LogSelectionList::verify_selections(outputStream* out) const {
   bool valid = true;
 
@@ -67,6 +69,8 @@ bool LogSelectionList::parse(const char* str, outputStream* errstream) {
     str = DefaultExpressionString;
   }
   char* copy = os::strdup_check_oom(str, mtLogging);
+  char* injected_copy = nullptr;
+
   // Split string on commas
   for (char *comma_pos = copy, *cur = copy; success; cur = comma_pos + 1) {
     if (_nselections == MaxSelections) {
@@ -83,6 +87,22 @@ bool LogSelectionList::parse(const char* str, outputStream* errstream) {
       *comma_pos = '\0';
     }
 
+    if (strncmp(cur, "aot*", 4) == 0 && injected_copy == nullptr) {
+      // Special case: because -Xlog:aot* matches with (unaliased) aot logs, we
+      // need to inject an "cds*" tag as well.
+      //
+      // This is not necessary for -Xlog:aot+mirror*, because this will not
+      // match any aot logs, and the aliasing will be done inside LogSelection::parse().
+
+      size_t len = strlen(cur);
+      injected_copy = (char*)os::malloc(len+10, mtLogging);
+      strcpy(injected_copy + 1, cur);
+      injected_copy[0] = ','; // will be skipped
+      injected_copy[1] = 'c';
+      injected_copy[2] = 'd';
+      injected_copy[3] = 's';
+      _cds_tag_specified --;
+    }
     LogSelection selection = LogSelection::parse(cur, errstream);
     if (selection == LogSelection::Invalid) {
       success = false;
@@ -91,7 +111,14 @@ bool LogSelectionList::parse(const char* str, outputStream* errstream) {
     _selections[_nselections++] = selection;
 
     if (comma_pos == nullptr) {
-      break;
+      if (injected_copy != nullptr) {
+        os::free(copy);
+        copy = injected_copy;
+        comma_pos = copy;
+        injected_copy = nullptr;
+      } else {
+        break;
+      }
     }
   }
 

src/hotspot/share/logging/logTagSet.cpp

@@ -93,8 +93,16 @@ void LogTagSet::log(const LogMessageBuffer& msg) {
   }
 }
 
+extern int _cds_tag_specified;
+
 void LogTagSet::label(outputStream* st, const char* separator) const {
-  for (size_t i = 0; i < _ntags; i++) {
+  size_t i = 0;
+  if (_ntags > 0 && _tag[0] == LogTag::_cds && _cds_tag_specified == 0) {
+    st->print("%s", "aot");
+    i++;
+  }
+
+  for (; i < _ntags; i++) {
     st->print("%s%s", (i == 0 ? "" : separator), LogTag::name(_tag[i]));
   }
 }