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

[Saiyedul Islam via llvm-commits]

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@@ -198,4 +200,189 @@ 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>],...]
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saiislam wrote:

Please add a couple of examples of env variables for different types and levels.

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