[CSSPGO] Passing the clang driver switch -fpseudo-probe-for-profiling to the linker.

[hoy]

Summary

As titled.

[hoy]

Fixing test failure on Windows.

[wenlei]

clang/lib/Driver/ToolChains/CommonArgs.cpp

609

getLastArg(options::OPT_fpseudo_probe_for_profiling, options::OPT_fno_pseudo_probe_for_profiling instead?

[hoy]

clang/lib/Driver/ToolChains/CommonArgs.cpp

609

Good point, changed to

Args.hasFlag(options::OPT_fpseudo_probe_for_profiling, options::OPT_fno_pseudo_probe_for_profiling)

which matches the last positive flag

bool ArgList::hasFlag(OptSpecifier Pos, OptSpecifier Neg, bool Default) const {
  if (Arg *A = getLastArg(Pos, Neg))
    return A->getOption().matches(Pos);
  return Default;
}

[hoy]

Addressing Wenleis' feedback.

[wenlei]

lgtm, thanks.

[hoy]

Rebasing.

[wmi]

clang/lib/Driver/ToolChains/CommonArgs.cpp

609–610

The third arg of Args.hasFlag defaults to true, which means -plugin-opt=pseudo-probe-for-profiling will be inserted even if no -fpseudo-probe-for-profiling or -fno-pseudo-probe-for-profiling is provided. Is it expected?

clang/test/Driver/pseudo-probe-lto.c

7

Better add another check of NOPROBE when neither -fpseudo-probe-for-profiling or -fno-pseudo-probe-for-profiling is provided.

[hoy]

clang/lib/Driver/ToolChains/CommonArgs.cpp

609–610

Good catch, it's not expected. Thanks!

[hoy]

Addressing Wei's comment.

[hoy]

clang/test/Driver/pseudo-probe-lto.c

7

Good point, test case added.

[wmi]

LGTM.

clang/include/clang/Driver/Options.td

def fprofile_exclude_files_EQ : Joined<["-"], "fprofile-exclude-files=">,
     ShouldParseIf<!strconcat(fprofile_arcs.KeyPath, "||", ftest_coverage.KeyPath)>;
 def fprofile_update_EQ : Joined<["-"], "fprofile-update=">,
     Group<f_Group>, Flags<[CC1Option, CoreOption]>, Values<"atomic,prefer-atomic,single">,
     MetaVarName<"<method>">, HelpText<"Set update method of profile counters (atomic,prefer-atomic,single)">,
     MarshallingInfoFlag<CodeGenOpts<"AtomicProfileUpdate">>;
 defm pseudo_probe_for_profiling : BoolFOption<"pseudo-probe-for-profiling",
   CodeGenOpts<"PseudoProbeForProfiling">, DefaultsToFalse,
   ChangedBy<PosFlag, [], "Emit">, ResetBy<NegFlag, [], "Do not emit">,
-  BothFlags<[NoXarchOption, CC1Option], " pseudo probes for sample profiler">>;
+  BothFlags<[NoXarchOption, CC1Option], " pseudo probes for sample profiling">>;
 def forder_file_instrumentation : Flag<["-"], "forder-file-instrumentation">,
     Group<f_Group>, Flags<[CC1Option, CoreOption]>,
     HelpText<"Generate instrumented code to collect order file into default.profraw file (overridden by '=' form of option or LLVM_PROFILE_FILE env var)">;
 
 defm addrsig : BoolFOption<"addrsig",
   CodeGenOpts<"Addrsig">, DefaultsToFalse,
   ChangedBy<PosFlag, [], "Emit">, ResetBy<NegFlag, [], "Don't emit">,
   BothFlags<[CoreOption], " an address-significance table">>;

clang/lib/Driver/ToolChains/CommonArgs.cpp

#endif
   if (auto *A = Args.getLastArg(options::OPT_flegacy_pass_manager,
                                 options::OPT_fno_legacy_pass_manager)) {
     if (A->getOption().matches(options::OPT_flegacy_pass_manager))
       CmdArgs.push_back("-plugin-opt=legacy-pass-manager");
     else
       CmdArgs.push_back("-plugin-opt=new-pass-manager");
   }
 
+  // Pass an option to enable pseudo probe emission.
+  if (Args.hasArg(options::OPT_fpseudo_probe_for_profiling))
+    CmdArgs.push_back("-plugin-opt=pseudo-probe-for-profiling");
+
   // Setup statistics file output.
   SmallString<128> StatsFile = getStatsFileName(Args, Output, Input, D);
   if (!StatsFile.empty())
     CmdArgs.push_back(
         Args.MakeArgString(Twine("-plugin-opt=stats-file=") + StatsFile));
 
   addX86AlignBranchArgs(D, Args, CmdArgs, /*IsLTO=*/true);
 

clang/test/Driver/pseudo-probe-lto.c

+// RUN: touch %t.o
+// RUN: %clang -### %t.o -target x86_64-unknown-linux -flto -fpseudo-probe-for-profiling 2>&1 | FileCheck %s
+// RUN: %clang -### %t.o -target x86_64-unknown-linux -flto=thin -fpseudo-probe-for-profiling 2>&1 | FileCheck %s
+
+// CHECK: -plugin-opt=pseudo-probe-for-profiling