[llvm] [OFFLOAD] Add support for more fine grained debug messages control (PR #165416)

[Joseph Huber via llvm-commits]

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@@ -198,4 +200,200 @@ inline uint32_t getDebugLevel() {
     }                                                                          \
   } while (false)
 
+// New macros that will allow for more granular control over debugging output
+// Each message can be classified by Component, Type and Level
+// Component: The broad component of the offload runtime emitting the message.
+// Type: A cross-component classification of messages
+// Level: The verbosity level of the message
+//
+// The component is pulled from the TARGET_NAME macro, Type and Level can be
+// defined for each debug message but by default they are "default" and "1"
+// respectively.
+//
+// For liboffload and plugins, use OFFLOAD_DEBUG(...)
+// For libomptarget, use OPENMP_DEBUG(...)
+// Constructing messages should be done using C++ stream style syntax.
+//
+// Usage examples:
+// OFFLOAD_DEBUG("type1", 2, "This is a level 2 message of type1");
+// OFFLOAD_DEBUG("Init", "This is a default level of the init type");
+// OPENMP_DEBUG("This is a level 1 message of the default type");
+// OFFLOAD_DEBUG("Init", 3, NumDevices << " were initialized\n");
+// OFFLOAD_DEBUG("Kernel", "Starting kernel " << KernelName << " on device " <<
+//               DeviceId);
+//
+// Message output can be controlled by setting LIBOMPTARGET_DEBUG or
+// LIBOFFLOAD_DEBUG environment variables. Their syntax is as follows:
+// [integer]|all|<type1>[:<level1>][,<type2>[:<level2>],...]
+//
+// 0 : Disable all debug messages
+// all : Enable all level 1 debug messages
+// integer : Set the default level for all messages
+// <type> : Enable only messages of the specified type and level (more than one
+//          can be specified). Components are also supported as
+//          types.
+// <level> : Set the verbosity level for the specified type (default is 1)
+//
+// Some examples:
+// LIBOFFLOAD_DEBUG=1  (Print all messages of level 1 or lower)
+// LIBOFFLOAD_DEBUG=5  (Print all messages of level 5 or lower)
+// LIBOFFLOAD_DEBUG=init (Print messages of type "init" of level 1 or lower)
+// LIBOFFLOAD_DEBUG=init:3,mapping:2 (Print messages of type "init" of level 3
+//                                   or lower and messages of type "mapping" of
+//                                   level 2 or lower)
+// LIBOFFLOAD_DEBUG=omptarget:4, init (Print messages from component "omptarget" of
+//                                   level 4 or lower and messages of type
+//                                   "init" of level 1 or lower)
+//
+// For very specific cases where more control is needed, use OFFLOAD_DEBUG_RAW
+// or OFFLOAD_DEBUG_BASE. See below for details.
+
+namespace llvm::offload::debug {
+
+#ifdef OMPTARGET_DEBUG
+
+struct DebugFilter {
+  StringRef Type;
+  uint32_t Level;
+};
+
+struct DebugSettings {
+  bool Enabled = false;
+  uint32_t DefaultLevel = 1;
+  llvm::SmallVector<DebugFilter> Filters;
+};
+
+/// dbgs - Return a circular-buffered debug stream.
+inline llvm::raw_ostream &dbgs() {
+  // Do one-time initialization in a thread-safe way.
+  static struct dbgstream {
+    llvm::circular_raw_ostream strm;
+
+    dbgstream() : strm(llvm::errs(), "*** Debug Log Output ***\n", 0) {}
+  } thestrm;
+
+  return thestrm.strm;
+}
+
+inline DebugFilter parseDebugFilter(StringRef Filter) {
+  size_t Pos = Filter.find(':');
+  if (Pos == StringRef::npos)
+    return {Filter, 1};
+
+  StringRef Type = Filter.slice(0, Pos);
+  uint32_t Level = 1;
+  if (Filter.slice(Pos + 1, Filter.size()).getAsInteger(10, Level))
+    Level = 1;
+
+  return {Type, Level};
+}
+
+inline DebugSettings &getDebugSettings() {
+  static DebugSettings Settings;
+  static std::once_flag Flag{};
+  std::call_once(Flag, []() {
+    printf("Configuring debug settings\n");
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jhuber6 wrote:

Leftover debugging?

https://github.com/llvm/llvm-project/pull/165416