[Driver] pass -fjmc to LTO

[ychen]

Summary

So the behavior is consistent with non-LTO mode.

clang/lib/Driver/ToolChains/CommonArgs.cpp

if (CSPGOGenerateArg) {
     SmallString<128> Path(
         ProfileUseArg->getNumValues() == 0 ? "" : ProfileUseArg->getValue());
     if (Path.empty() || llvm::sys::fs::is_directory(Path))
       llvm::sys::path::append(Path, "default.profdata");
     CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=cs-profile-path=") +
                                          Path));
   }
 
+  // This controls whether or not we perform JustMyCode instrumentation.
+  if (Args.hasFlag(options::OPT_fjmc, options::OPT_fno_jmc, false)) {
+    if (ToolChain.getEffectiveTriple().isOSBinFormatELF())
+      CmdArgs.push_back("-plugin-opt=-enable-jmc-instrument");
+    else
+      D.Diag(clang::diag::warn_drv_fjmc_for_elf_only);
+  }
+
   // 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));
 
   // Setup crash diagnostics dir.
   if (Arg *A = Args.getLastArg(options::OPT_fcrash_diagnostics_dir))

clang/test/Driver/clang_f_opts.c

 // RUN: %clang -### -xobjective-c %s 2>&1 | FileCheck -check-prefix=CHECK_NO_DISABLE_DIRECT %s
 // CHECK_DISABLE_DIRECT: -fobjc-disable-direct-methods-for-testing
 // CHECK_NO_DISABLE_DIRECT-NOT: -fobjc-disable-direct-methods-for-testing
 
 // RUN: %clang -### -S -fjmc -target x86_64-unknown-linux %s 2>&1 | FileCheck -check-prefixes=CHECK_JMC_WARN,CHECK_NOJMC %s
 // RUN: %clang -### -S -fjmc -target x86_64-pc-windows-msvc %s 2>&1 | FileCheck -check-prefixes=CHECK_JMC_WARN_NOT_ELF,CHECK_NOJMC %s
 // RUN: %clang -### -S -fjmc -g -target x86_64-unknown-linux %s 2>&1 | FileCheck -check-prefix=CHECK_JMC %s
 // RUN: %clang -### -S -fjmc -g -fno-jmc -target x86_64-unknown-linux %s 2>&1 | FileCheck -check-prefix=CHECK_NOJMC %s
+// RUN: %clang -### -fjmc -g -flto -target x86_64-pc-windows-msvc %s 2>&1 | FileCheck -check-prefixes=CHECK_JMC_WARN_NOT_ELF,CHECK_NOJMC_LTO %s
+// RUN: %clang -### -fjmc -g -flto -target x86_64-unknown-linux %s 2>&1 | FileCheck -check-prefix=CHECK_JMC_LTO %s
+// RUN: %clang -### -fjmc -g -flto -fno-jmc -target x86_64-unknown-linux %s 2>&1 | FileCheck -check-prefix=CHECK_NOJMC_LTO %s
 // CHECK_JMC_WARN: -fjmc requires debug info. Use -g or debug options that enable debugger's stepping function; option ignored
 // CHECK_JMC_WARN_NOT_ELF: -fjmc works only for ELF; option ignored
 // CHECK_NOJMC-NOT: -fjmc
 // CHECK_JMC: -fjmc
+// CHECK_NOJMC_LTO-NOT: -plugin-opt=-enable-jmc-instrument
+// CHECK_JMC_LTO: -plugin-opt=-enable-jmc-instrument
 
 // RUN: %clang -### -fintegrated-objemitter -target x86_64 %s 2>&1 | FileCheck -check-prefix=CHECK-INT-OBJEMITTER %s
 // CHECK-INT-OBJEMITTER-NOT: unsupported option '-fintegrated-objemitter' for target
 // RUN: %clang -### -fno-integrated-objemitter -target x86_64 %s 2>&1 | FileCheck -check-prefix=CHECK-NOINT-OBJEMITTER %s
 // CHECK-NOINT-OBJEMITTER: unsupported option '-fno-integrated-objemitter' for target