[llvm] Introduce a "log level" support for DEBUG_TYPE (PR #150855)

[Mehdi Amini via llvm-commits]

================
@@ -38,25 +40,46 @@
 
 using namespace llvm;
 
+/// Parse a debug type string into a pair of the debug type and the debug level.
+/// The expected format is "type[:level]", where the level is an optional
+/// integer.
+static std::pair<std::string, int> parseDebugType(StringRef DbgType) {
+  auto [Type, LevelStr] = DbgType.split(':');
+  int Level;
+  if (!to_integer(LevelStr, Level, 10))
+    Level = 0;
+  return std::make_pair(Type.str(), Level);
+}
+
 // Even though LLVM might be built with NDEBUG, define symbols that the code
 // built without NDEBUG can depend on via the llvm/Support/Debug.h header.
 namespace llvm {
 /// Exported boolean set by the -debug option.
 bool DebugFlag = false;
 
-static ManagedStatic<std::vector<std::string>> CurrentDebugType;
+/// The current debug type and an optional debug level.
+/// The debug level is the verbosity of the debug output.
+/// The default level is 0, which is the most verbose.
+/// The level can be set to 1, 2, 3, etc. to control the verbosity of the
+/// output. The level can be set to -1 to disable the output.
+static ManagedStatic<std::vector<std::pair<std::string, int>>> CurrentDebugType;
 
 /// Return true if the specified string is the debug type
 /// specified on the command line, or if none was specified on the command line
 /// with the -debug-only=X option.
-bool isCurrentDebugType(const char *DebugType) {
+bool isCurrentDebugType(const char *DebugType, int Level) {
   if (CurrentDebugType->empty())
     return true;
   // See if DebugType is in list. Note: do not use find() as that forces us to
   // unnecessarily create an std::string instance.
   for (auto &d : *CurrentDebugType) {
-    if (d == DebugType)
-      return true;
+    if (d.first == DebugType) {
+      if (d.second < 0)
+        return false;
+      if (d.second == 0)
+        return true;
+      return d.second >= Level;
----------------
joker-eph wrote:

This is the exact same thing, you're hallucinating.

https://github.com/llvm/llvm-project/pull/150855