================
@@ -649,6 +649,24 @@ static void addPGOAndCoverageFlags(const ToolChain &TC,
Compilation &C,
}
}
+ if (auto *ColdFuncCoverageArg = Args.getLastArg(
+ options::OPT_fprofile_generate_cold_function_coverage,
+ options::OPT_fprofile_generate_cold_function_coverage_EQ)) {
+ SmallString<128> Path(
+ ColdFuncCoverageArg->getOption().matches(
+ options::OPT_fprofile_generate_cold_function_coverage_EQ)
+ ? ColdFuncCoverageArg->getValue()
+ : "");
+ llvm::sys::path::append(Path, "default_%m.profraw");
+ CmdArgs.push_back("-mllvm");
+ CmdArgs.push_back(Args.MakeArgString(
+ Twine("--instrument-cold-function-coverage-path=") + Path));
+ CmdArgs.push_back("-mllvm");
+ CmdArgs.push_back("--instrument-cold-function-coverage");
----------------
wlei-llvm wrote:
I really like this idea, however, this seems indeed not easy(needs a lot of
refactoring).
As you said, the `InstrProfileOutput` filed is shared with other PGO flag(in
our case, it's the `fprofile-sample-use=`) , see
[`PGOOptions.ProfileFIle`](https://github.com/llvm/llvm-project/blob/main/llvm/include/llvm/Support/PGOOptions.h#L43).
One thing we can do is to split this field into two: `ProfileUseFile` and
`ProfileGenFole`, let all `profile-<instr>-gererate` go to `ProfileGenFile`
and let `sample-use/instr-use go` to `ProfileUseFile`. I think that's doable
and not a big change(maybe a separate diff). Then in sample-use case, we can
use the `ProfileGenFIle` path for cold coverage work. WDYT?
Though it would still not be perfect, the logic here
https://github.com/llvm/llvm-project/blob/main/clang/lib/CodeGen/BackendUtil.cpp#L811-L841
is complicated/ would still need more refactoring. I was stuck here when
thinking if `-fprofile-sample-use` and `--fprofile-instrument-path=` are both
used, which branch(`CodeGenOpts.hasProfileIRInstr()` or
`!CodeGenOpts.SampleProfileFile.empty()`) should it belongs to.
For this version, I just removed the duplicated
flag(`--pgo-instrument-cold-function-only`) and added a FIXME comment to
explain this.
https://github.com/llvm/llvm-project/pull/109837
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