[clang] [llvm] [InstrPGO] Instrument sampling profile based cold function (PR #109837)

[via cfe-commits]

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@@ -1784,6 +1784,12 @@ defm debug_info_for_profiling : BoolFOption<"debug-info-for-profiling",
   PosFlag<SetTrue, [], [ClangOption, CC1Option],
           "Emit extra debug info to make sample profile more accurate">,
   NegFlag<SetFalse>>;
+def fprofile_generate_cold_function_coverage : Flag<["-"], "fprofile-generate-cold-function-coverage">, 
+    Group<f_Group>, Visibility<[ClangOption, CLOption]>,
+    HelpText<"Generate instrumented code to cold functions into default.profraw file (overridden by '=' form of option or LLVM_PROFILE_FILE env var)">;
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WenleiHe wrote:

The help text doesn't parse. Did you mean something like:

```
Generate instrumented code to collect coverage info for cold functions into default.profraw file (overridden by '=' form of option or LLVM_PROFILE_FILE env var)
```

https://github.com/llvm/llvm-project/pull/109837