[LTO][clang] Teaching Clang to Pass Plugin Options to the AIX Linker

[qiongsiwu1]

Summary

This patch teaches clang to use the prefix -bplugin_opt: (instead of -plugin-opt) on AIX, when passing plugin options to the linker. This patch follows https://reviews.llvm.org/D134668.

We put the code that decides what plugin option prefix to use at the top of the function tools::addLTOOptions. The plugin option prefix, the mcpu prefix, and the opt level prefix are different on AIX. We thought about choosing the strings in a function that reads the linker name and the target triple, or we could push the logic into different derived ToolChain classes. But this logic would not be used anywhere else, so these alternatives looked too complicated for what they did. Therefore we are doing it the current way. That said, I am all ears for suggestions to improve this code!

Subsequent code uses the PluginOptPrefix variable consistently instead of the hardcoded -plugin-opt.

[qiongsiwu1]

Fix the test failure on Windows.

[qiongsiwu1]

Fix test case on Windows.

[qiongsiwu1]

Try fixing the test case on Windows, hopefully one last time.

[MaskRay]

clang/test/Driver/lto-aix.c

3

Replace legacy -target with --target=

[qiongsiwu1]

Address a code review comment.

[MaskRay]

LGTM

clang/lib/Driver/ToolChains/CommonArgs.cpp

72

Adding Twine to one operand of + suffices.

77

Adding Twine to one operand of + suffices.

493

delete blank line

[qiongsiwu1]

Address review comments. Remove unnecessary Twines.

[qiongsiwu1]

Rebase with latest main.

clang/lib/Driver/ToolChains/AIX.h

public:
   bool parseInlineAsmUsingAsmParser() const override {
     return ParseInlineAsmUsingAsmParser;
   }
   bool isPICDefault() const override { return true; }
   bool isPIEDefault(const llvm::opt::ArgList &Args) const override {
     return false;
   }
   bool isPICDefaultForced() const override { return true; }
+  bool HasNativeLLVMSupport() const override { return true; }
 
   void
   AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                             llvm::opt::ArgStringList &CC1Args) const override;
 
   void AddClangCXXStdlibIncludeArgs(
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override;

clang/lib/Driver/ToolChains/AIX.cpp

void aix::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   // language link invocations. This has to come before AddLinkerInputs as the
   // implied option needs to precede any other '-bcdtors' settings or
   // '-bnocdtors' that '-Wl' might forward.
   CmdArgs.push_back("-bcdtors:all:0:s");
 
   // Specify linker input file(s).
   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
 
+  if (D.isUsingLTO()) {
+    assert(!Inputs.empty() && "Must have at least one input.");
+    addLTOOptions(ToolChain, Args, CmdArgs, Output, Inputs[0],
+                  D.getLTOMode() == LTOK_Thin);
+  }
+
   if (Args.hasArg(options::OPT_shared) && !hasExportListLinkerOpts(CmdArgs)) {
 
     const char *CreateExportListExec = Args.MakeArgString(
         path::parent_path(ToolChain.getDriver().ClangExecutable) +
         "/llvm-nm");
     ArgStringList CreateExportCmdArgs;
 
     std::string CreateExportListPath =

clang/lib/Driver/ToolChains/CommonArgs.h

SmallString<128> getStatsFileName(const llvm::opt::ArgList &Args,
                                   const InputInfo &Input, const Driver &D);
 
 /// \p Flag must be a flag accepted by the driver with its leading '-' removed,
 //     otherwise '-print-multi-lib' will not emit them correctly.
 void addMultilibFlag(bool Enabled, const char *const Flag,
                      Multilib::flags_list &Flags);
 
 void addX86AlignBranchArgs(const Driver &D, const llvm::opt::ArgList &Args,
-                           llvm::opt::ArgStringList &CmdArgs, bool IsLTO);
+                           llvm::opt::ArgStringList &CmdArgs, bool IsLTO,
+                           const StringRef PluginOptPrefix = "");
 
 void checkAMDGPUCodeObjectVersion(const Driver &D,
                                   const llvm::opt::ArgList &Args);
 
 unsigned getAMDGPUCodeObjectVersion(const Driver &D,
                                     const llvm::opt::ArgList &Args);
 
 bool haveAMDGPUCodeObjectVersionArgument(const Driver &D,
                                          const llvm::opt::ArgList &Args);
 
 void addMachineOutlinerArgs(const Driver &D, const llvm::opt::ArgList &Args,
                             llvm::opt::ArgStringList &CmdArgs,
-                            const llvm::Triple &Triple, bool IsLTO);
+                            const llvm::Triple &Triple, bool IsLTO,
+                            const StringRef PluginOptPrefix = "");
 
 void addOpenMPDeviceRTL(const Driver &D, const llvm::opt::ArgList &DriverArgs,
                         llvm::opt::ArgStringList &CC1Args,
                         StringRef BitcodeSuffix, const llvm::Triple &Triple);
 } // end namespace tools
 } // end namespace driver
 } // end namespace clang
 
 #endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_COMMONARGS_H

clang/lib/Driver/ToolChains/CommonArgs.cpp

 #include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/YAMLParser.h"
 
 using namespace clang::driver;
 using namespace clang::driver::tools;
 using namespace clang;
 using namespace llvm::opt;
 
-static void renderRpassOptions(const ArgList &Args, ArgStringList &CmdArgs) {
+static void renderRpassOptions(const ArgList &Args, ArgStringList &CmdArgs,
+                               const StringRef PluginOptPrefix) {
   if (const Arg *A = Args.getLastArg(options::OPT_Rpass_EQ))
-    CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=-pass-remarks=") +
-                                         A->getValue()));
+    CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) +
+                                         "-pass-remarks=" + A->getValue()));
 
   if (const Arg *A = Args.getLastArg(options::OPT_Rpass_missed_EQ))
     CmdArgs.push_back(Args.MakeArgString(
-        Twine("-plugin-opt=-pass-remarks-missed=") + A->getValue()));
+        Twine(PluginOptPrefix) + "-pass-remarks-missed=" + A->getValue()));
 
   if (const Arg *A = Args.getLastArg(options::OPT_Rpass_analysis_EQ))
     CmdArgs.push_back(Args.MakeArgString(
-        Twine("-plugin-opt=-pass-remarks-analysis=") + A->getValue()));
+        Twine(PluginOptPrefix) + "-pass-remarks-analysis=" + A->getValue()));
 }
 
 static void renderRemarksOptions(const ArgList &Args, ArgStringList &CmdArgs,
                                  const llvm::Triple &Triple,
                                  const InputInfo &Input,
-                                 const InputInfo &Output) {
+                                 const InputInfo &Output,
+                                 const StringRef PluginOptPrefix) {
   StringRef Format = "yaml";
   if (const Arg *A = Args.getLastArg(options::OPT_fsave_optimization_record_EQ))
     Format = A->getValue();
 
   SmallString<128> F;
   const Arg *A = Args.getLastArg(options::OPT_foptimization_record_file_EQ);
   if (A)
     F = A->getValue();
   else if (Output.isFilename())
     F = Output.getFilename();
 
   assert(!F.empty() && "Cannot determine remarks output name.");
   // Append "opt.ld.<format>" to the end of the file name.
-  CmdArgs.push_back(
-      Args.MakeArgString(Twine("-plugin-opt=opt-remarks-filename=") + F +
-                         Twine(".opt.ld.") + Format));
+  CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) +
+                                       "opt-remarks-filename=" + F +
+                                       ".opt.ld." + Format));
 
   if (const Arg *A =
           Args.getLastArg(options::OPT_foptimization_record_passes_EQ))
     CmdArgs.push_back(Args.MakeArgString(
-        Twine("-plugin-opt=opt-remarks-passes=") + A->getValue()));
+        Twine(PluginOptPrefix) + "opt-remarks-passes=" + A->getValue()));
 
-  CmdArgs.push_back(Args.MakeArgString(
-      Twine("-plugin-opt=opt-remarks-format=") + Format.data()));
+  CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) +
+                                       "opt-remarks-format=" + Format.data()));
 }
 
 static void renderRemarksHotnessOptions(const ArgList &Args,
-                                        ArgStringList &CmdArgs) {
+                                        ArgStringList &CmdArgs,
+                                        const StringRef PluginOptPrefix) {
   if (Args.hasFlag(options::OPT_fdiagnostics_show_hotness,
                    options::OPT_fno_diagnostics_show_hotness, false))
-    CmdArgs.push_back("-plugin-opt=opt-remarks-with-hotness");
+    CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) +
+                                         "opt-remarks-with-hotness"));
 
   if (const Arg *A =
           Args.getLastArg(options::OPT_fdiagnostics_hotness_threshold_EQ))
-    CmdArgs.push_back(Args.MakeArgString(
-        Twine("-plugin-opt=opt-remarks-hotness-threshold=") + A->getValue()));
+    CmdArgs.push_back(
+        Args.MakeArgString(Twine(PluginOptPrefix) +
+                           "opt-remarks-hotness-threshold=" + A->getValue()));
 }
 
 void tools::addPathIfExists(const Driver &D, const Twine &Path,
                             ToolChain::path_list &Paths) {
   if (D.getVFS().exists(Path))
     Paths.push_back(Path.str());
 }
 

 // CloudABI and PS4/PS5 use -ffunction-sections and -fdata-sections by default.
 bool tools::isUseSeparateSections(const llvm::Triple &Triple) {
   return Triple.getOS() == llvm::Triple::CloudABI || Triple.isPS();
 }
 
 void tools::addLTOOptions(const ToolChain &ToolChain, const ArgList &Args,
                           ArgStringList &CmdArgs, const InputInfo &Output,
                           const InputInfo &Input, bool IsThinLTO) {
+  const bool IsOSAIX = ToolChain.getTriple().isOSAIX();
   const char *Linker = Args.MakeArgString(ToolChain.GetLinkerPath());
   const Driver &D = ToolChain.getDriver();
   if (llvm::sys::path::filename(Linker) != "ld.lld" &&
       llvm::sys::path::stem(Linker) != "ld.lld") {
     // Tell the linker to load the plugin. This has to come before
-    // AddLinkerInputs as gold requires -plugin to come before any -plugin-opt
-    // that -Wl might forward.
+    // AddLinkerInputs as gold requires -plugin and AIX ld requires -bplugin to
+    // come before any -plugin-opt/-bplugin_opt that -Wl might forward.
+    const char *PluginPrefix = IsOSAIX ? "-bplugin:" : "";
+    const char *PluginName = IsOSAIX ? "/libLTO" : "/LLVMgold";
+
+    if (!IsOSAIX)
       CmdArgs.push_back("-plugin");
 
 #if defined(_WIN32)
     const char *Suffix = ".dll";
 #elif defined(__APPLE__)
     const char *Suffix = ".dylib";
 #else
     const char *Suffix = ".so";
 #endif
 
     SmallString<1024> Plugin;
-    llvm::sys::path::native(
-        Twine(D.Dir) + "/../" CLANG_INSTALL_LIBDIR_BASENAME "/LLVMgold" +
-            Suffix,
+    llvm::sys::path::native(Twine(D.Dir) +
+                                "/../" CLANG_INSTALL_LIBDIR_BASENAME +
+                                PluginName + Suffix,
                             Plugin);
-    CmdArgs.push_back(Args.MakeArgString(Plugin));
+    CmdArgs.push_back(Args.MakeArgString(Twine(PluginPrefix) + Plugin));
   }
 
+  const char *PluginOptPrefix = IsOSAIX ? "-bplugin_opt:" : "-plugin-opt=";
+  const char *mcpuOptPrefix = IsOSAIX ? "-mcpu=" : "mcpu=";
+  const char *OptLevelPrefix = IsOSAIX ? "-O" : "O";
+
   // Note, this solution is far from perfect, better to encode it into IR
   // metadata, but this may not be worth it, since it looks like aranges is on
   // the way out.
   if (Args.hasArg(options::OPT_gdwarf_aranges)) {
-    CmdArgs.push_back(
-        Args.MakeArgString("-plugin-opt=-generate-arange-section"));
+    CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) +
+                                         "-generate-arange-section"));
   }
 
   // Try to pass driver level flags relevant to LTO code generation down to
   // the plugin.
 
   // Handle flags for selecting CPU variants.
   std::string CPU = getCPUName(D, Args, ToolChain.getTriple());
   if (!CPU.empty())
-    CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=mcpu=") + CPU));
+    CmdArgs.push_back(
+        Args.MakeArgString(Twine(PluginOptPrefix) + mcpuOptPrefix + CPU));
 
   if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {
     // The optimization level matches
     // CompilerInvocation.cpp:getOptimizationLevel().
     StringRef OOpt;
     if (A->getOption().matches(options::OPT_O4) ||
         A->getOption().matches(options::OPT_Ofast))
       OOpt = "3";
     else if (A->getOption().matches(options::OPT_O)) {
       OOpt = A->getValue();
       if (OOpt == "g")
         OOpt = "1";
       else if (OOpt == "s" || OOpt == "z")
         OOpt = "2";
     } else if (A->getOption().matches(options::OPT_O0))
       OOpt = "0";
     if (!OOpt.empty())
-      CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=O") + OOpt));
-  }
-
-  if (Args.hasArg(options::OPT_gsplit_dwarf)) {
       CmdArgs.push_back(
-        Args.MakeArgString(Twine("-plugin-opt=dwo_dir=") +
-            Output.getFilename() + "_dwo"));
+          Args.MakeArgString(Twine(PluginOptPrefix) + OptLevelPrefix + OOpt));
   }
 
+  if (Args.hasArg(options::OPT_gsplit_dwarf))
+    CmdArgs.push_back(Args.MakeArgString(
+        Twine(PluginOptPrefix) + "dwo_dir=" + Output.getFilename() + "_dwo"));
+
   if (IsThinLTO)
-    CmdArgs.push_back("-plugin-opt=thinlto");
+    CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) + "thinlto"));
 
   StringRef Parallelism = getLTOParallelism(Args, D);
   if (!Parallelism.empty())
     CmdArgs.push_back(
-        Args.MakeArgString("-plugin-opt=jobs=" + Twine(Parallelism)));
+        Args.MakeArgString(Twine(PluginOptPrefix) + "jobs=" + Parallelism));
 
   // If an explicit debugger tuning argument appeared, pass it along.
-  if (Arg *A = Args.getLastArg(options::OPT_gTune_Group,
-                               options::OPT_ggdbN_Group)) {
+  if (Arg *A =
+          Args.getLastArg(options::OPT_gTune_Group, options::OPT_ggdbN_Group)) {
     if (A->getOption().matches(options::OPT_glldb))
-      CmdArgs.push_back("-plugin-opt=-debugger-tune=lldb");
+      CmdArgs.push_back(
+          Args.MakeArgString(Twine(PluginOptPrefix) + "-debugger-tune=lldb"));
     else if (A->getOption().matches(options::OPT_gsce))
-      CmdArgs.push_back("-plugin-opt=-debugger-tune=sce");
+      CmdArgs.push_back(
+          Args.MakeArgString(Twine(PluginOptPrefix) + "-debugger-tune=sce"));
     else if (A->getOption().matches(options::OPT_gdbx))
-      CmdArgs.push_back("-plugin-opt=-debugger-tune=dbx");
+      CmdArgs.push_back(
+          Args.MakeArgString(Twine(PluginOptPrefix) + "-debugger-tune=dbx"));
     else
-      CmdArgs.push_back("-plugin-opt=-debugger-tune=gdb");
+      CmdArgs.push_back(
+          Args.MakeArgString(Twine(PluginOptPrefix) + "-debugger-tune=gdb"));
   }
 
   bool UseSeparateSections =
       isUseSeparateSections(ToolChain.getEffectiveTriple());
 
   if (Args.hasFlag(options::OPT_ffunction_sections,
                    options::OPT_fno_function_sections, UseSeparateSections))
-    CmdArgs.push_back("-plugin-opt=-function-sections=1");
+    CmdArgs.push_back(
+        Args.MakeArgString(Twine(PluginOptPrefix) + "-function-sections=1"));
   else if (Args.hasArg(options::OPT_fno_function_sections))
-    CmdArgs.push_back("-plugin-opt=-function-sections=0");
+    CmdArgs.push_back(
+        Args.MakeArgString(Twine(PluginOptPrefix) + "-function-sections=0"));
 
   if (Args.hasFlag(options::OPT_fdata_sections, options::OPT_fno_data_sections,
                    UseSeparateSections))
-    CmdArgs.push_back("-plugin-opt=-data-sections=1");
+    CmdArgs.push_back(
+        Args.MakeArgString(Twine(PluginOptPrefix) + "-data-sections=1"));
   else if (Args.hasArg(options::OPT_fno_data_sections))
-    CmdArgs.push_back("-plugin-opt=-data-sections=0");
+    CmdArgs.push_back(
+        Args.MakeArgString(Twine(PluginOptPrefix) + "-data-sections=0"));
 
   // Pass an option to enable split machine functions.
   if (auto *A = Args.getLastArg(options::OPT_fsplit_machine_functions,
                                 options::OPT_fno_split_machine_functions)) {
     if (A->getOption().matches(options::OPT_fsplit_machine_functions))
-      CmdArgs.push_back("-plugin-opt=-split-machine-functions");
+      CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) +
+                                           "-split-machine-functions"));
   }
 
   if (Arg *A = getLastProfileSampleUseArg(Args)) {
     StringRef FName = A->getValue();
     if (!llvm::sys::fs::exists(FName))
       D.Diag(diag::err_drv_no_such_file) << FName;
     else
-      CmdArgs.push_back(
-          Args.MakeArgString(Twine("-plugin-opt=sample-profile=") + FName));
+      CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) +
+                                           "sample-profile=" + FName));
   }
 
   auto *CSPGOGenerateArg = Args.getLastArg(options::OPT_fcs_profile_generate,
                                            options::OPT_fcs_profile_generate_EQ,
                                            options::OPT_fno_profile_generate);
   if (CSPGOGenerateArg &&
       CSPGOGenerateArg->getOption().matches(options::OPT_fno_profile_generate))
     CSPGOGenerateArg = nullptr;
 
   auto *ProfileUseArg = getLastProfileUseArg(Args);
 
   if (CSPGOGenerateArg) {
-    CmdArgs.push_back(Args.MakeArgString("-plugin-opt=cs-profile-generate"));
+    CmdArgs.push_back(
+        Args.MakeArgString(Twine(PluginOptPrefix) + "cs-profile-generate"));
     if (CSPGOGenerateArg->getOption().matches(
             options::OPT_fcs_profile_generate_EQ)) {
       SmallString<128> Path(CSPGOGenerateArg->getValue());
       llvm::sys::path::append(Path, "default_%m.profraw");
-      CmdArgs.push_back(
-          Args.MakeArgString(Twine("-plugin-opt=cs-profile-path=") + Path));
+      CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) +
+                                           "cs-profile-path=" + Path));
     } else
-      CmdArgs.push_back(
-          Args.MakeArgString("-plugin-opt=cs-profile-path=default_%m.profraw"));
+      CmdArgs.push_back(Args.MakeArgString(
+          Twine(PluginOptPrefix) + "cs-profile-path=default_%m.profraw"));
   } else if (ProfileUseArg) {
     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));
+    CmdArgs.push_back(
+        Args.MakeArgString(Twine(PluginOptPrefix) + "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");
+      CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) +
+                                           "-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));
+        Args.MakeArgString(Twine(PluginOptPrefix) + "stats-file=" + StatsFile));
 
   // Setup crash diagnostics dir.
   if (Arg *A = Args.getLastArg(options::OPT_fcrash_diagnostics_dir))
     CmdArgs.push_back(Args.MakeArgString(
-        Twine("-plugin-opt=-crash-diagnostics-dir=") + A->getValue()));
+        Twine(PluginOptPrefix) + "-crash-diagnostics-dir=" + A->getValue()));
 
-  addX86AlignBranchArgs(D, Args, CmdArgs, /*IsLTO=*/true);
+  addX86AlignBranchArgs(D, Args, CmdArgs, /*IsLTO=*/true, PluginOptPrefix);
 
   // Handle remark diagnostics on screen options: '-Rpass-*'.
-  renderRpassOptions(Args, CmdArgs);
+  renderRpassOptions(Args, CmdArgs, PluginOptPrefix);
 
   // Handle serialized remarks options: '-fsave-optimization-record'
   // and '-foptimization-record-*'.
   if (willEmitRemarks(Args))
     renderRemarksOptions(Args, CmdArgs, ToolChain.getEffectiveTriple(), Input,
-                         Output);
+                         Output, PluginOptPrefix);
 
   // Handle remarks hotness/threshold related options.
-  renderRemarksHotnessOptions(Args, CmdArgs);
+  renderRemarksHotnessOptions(Args, CmdArgs, PluginOptPrefix);
 
   addMachineOutlinerArgs(D, Args, CmdArgs, ToolChain.getEffectiveTriple(),
-                         /*IsLTO=*/true);
+                         /*IsLTO=*/true, PluginOptPrefix);
 }
 
 void tools::addOpenMPRuntimeSpecificRPath(const ToolChain &TC,
                                           const ArgList &Args,
                                           ArgStringList &CmdArgs) {
 
   if (Args.hasFlag(options::OPT_fopenmp_implicit_rpath,
                    options::OPT_fno_openmp_implicit_rpath, true)) {

 }
 
 void tools::addMultilibFlag(bool Enabled, const char *const Flag,
                             Multilib::flags_list &Flags) {
   Flags.push_back(std::string(Enabled ? "+" : "-") + Flag);
 }
 
 void tools::addX86AlignBranchArgs(const Driver &D, const ArgList &Args,
-                                  ArgStringList &CmdArgs, bool IsLTO) {
+                                  ArgStringList &CmdArgs, bool IsLTO,
+                                  const StringRef PluginOptPrefix) {
   auto addArg = [&, IsLTO](const Twine &Arg) {
     if (IsLTO) {
-      CmdArgs.push_back(Args.MakeArgString("-plugin-opt=" + Arg));
+      assert(!PluginOptPrefix.empty() && "Cannot have empty PluginOptPrefix!");
+      CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) + Arg));
     } else {
       CmdArgs.push_back("-mllvm");
       CmdArgs.push_back(Args.MakeArgString(Arg));
     }
   };
 
   if (Args.hasArg(options::OPT_mbranches_within_32B_boundaries)) {
     addArg(Twine("-x86-branches-within-32B-boundaries"));

 bool tools::haveAMDGPUCodeObjectVersionArgument(
     const Driver &D, const llvm::opt::ArgList &Args) {
   return getAMDGPUCodeObjectArgument(D, Args) != nullptr;
 }
 
 void tools::addMachineOutlinerArgs(const Driver &D,
                                    const llvm::opt::ArgList &Args,
                                    llvm::opt::ArgStringList &CmdArgs,
-                                   const llvm::Triple &Triple, bool IsLTO) {
+                                   const llvm::Triple &Triple, bool IsLTO,
+                                   const StringRef PluginOptPrefix) {
   auto addArg = [&, IsLTO](const Twine &Arg) {
     if (IsLTO) {
-      CmdArgs.push_back(Args.MakeArgString("-plugin-opt=" + Arg));
+      assert(!PluginOptPrefix.empty() && "Cannot have empty PluginOptPrefix!");
+      CmdArgs.push_back(Args.MakeArgString(Twine(PluginOptPrefix) + Arg));
     } else {
       CmdArgs.push_back("-mllvm");
       CmdArgs.push_back(Args.MakeArgString(Arg));
     }
   };
 
   if (Arg *A = Args.getLastArg(options::OPT_moutline,
                                options::OPT_mno_outline)) {

clang/test/Driver/lto-aix.c

+// Test LTO path, mcpu and opt level options
+// RUN: %clang --target=powerpc-ibm-aix -### %s -flto -fuse-ld=ld -O3 2>&1 \
+// RUN:   | FileCheck -check-prefixes=LTOPATH,MCPUOPTLEVEL %s
+//
+// LTOPATH: "-bplugin:{{.*}}libLTO.{{so|dll|dylib}}"
+// MCPUOPTLEVEL: "-bplugin_opt:-mcpu={{.*}}" "-bplugin_opt:-O3"