[llvm-branch-commits] [compiler-rt] [llvm] [ctxprof] Track unhandled call targets (PR #131417)

[Snehasish Kumar via llvm-branch-commits]

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@@ -246,22 +246,37 @@ ContextNode *getFlatProfile(FunctionData &Data, GUID Guid,
 
 ContextNode *getUnhandledContext(FunctionData &Data, GUID Guid,
                                  uint32_t NumCounters) {
-  // 1) if we are under a root (regardless if this thread is collecting or not a
+
+  // 1) if we are currently collecting a contextual profile, fetch a ContextNode
+  // in the `Unhandled` set. We want to do this regardless of `ProfilingStarted`
+  // to (hopefully) offset the penalty of creating these contexts to before
+  // profiling.
+  //
+  // 2) if we are under a root (regardless if this thread is collecting or not a
   // contextual profile for that root), do not collect a flat profile. We want
   // to keep flat profiles only for activations that can't happen under a root,
   // to avoid confusing profiles. We can, for example, combine flattened and
   // flat profiles meaningfully, as we wouldn't double-count anything.
   //
-  // 2) to avoid lengthy startup, don't bother with flat profiles until the
+  // 3) to avoid lengthy startup, don't bother with flat profiles until the
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snehasish wrote:

"the profiling has started"? 

https://github.com/llvm/llvm-project/pull/131417