[PATCH] D28416: [PGO] Turn off comdat renaming in IR PGO by default

[David Li via Phabricator via llvm-commits]

davidxl added a comment.

needs a profile use test case such that a comdat function has multiple copies of profile data and the profile annotator can find the one with the matching hash.



================
Comment at: include/llvm/ProfileData/InstrProf.h:237
+
+/// Check if we can safely rename this Comdat function.
+bool canRenameComdatInIRPGO(const Function &F);
----------------
Add comments: instances of the same comdat function may have different control flows thus can not share the same counter variable. 


================
Comment at: include/llvm/ProfileData/InstrProf.h:238
+/// Check if we can safely rename this Comdat function.
+bool canRenameComdatInIRPGO(const Function &F);
+
----------------
canRenameComdatFunc


================
Comment at: lib/Transforms/Instrumentation/InstrProfiling.cpp:35
 
+cl::opt<bool> DoInstrprofVarHashpostfix(
+    "instrprof-var-hashpostfix",
----------------
-> DoHashBasedCounterSplit


================
Comment at: lib/Transforms/Instrumentation/InstrProfiling.cpp:37
+    "instrprof-var-hashpostfix",
+    cl::desc("Append hash to the instrprof variables"), cl::init(true));
+
----------------
"Rename counter variable of a comdat function based on cfg hash".


https://reviews.llvm.org/D28416