[llvm] [MemProf] Extend CallSite information to include potential callees. (PR #130441)

[Kazu Hirata via llvm-commits]

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@@ -342,6 +342,28 @@ using CallStackId = uint64_t;
 // A type representing the index into the call stack array.
 using LinearCallStackId = uint32_t;
 
+// Holds call site information with indexed frame contents.
+struct IndexedCallSiteInfo {
+  // The call stack ID for this call site
+  CallStackId CSId = 0;
+  // The GUIDs of the callees at this call site
+  std::vector<GlobalValue::GUID> CalleeGuids;
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kazutakahirata wrote:

May I suggest `SmallVector<GlobalValue::GUID, 0>` here for smaller metadata?  You might also consider `SmallVector<GlobalValue::GUID, 1>` because most call sites have just one callee.

https://github.com/llvm/llvm-project/pull/130441