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

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`.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D134820

clang/lib/Driver/ToolChains/AIX.cpp

@@ -191,6 +191,12 @@ void aix::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   // 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(

clang/lib/Driver/ToolChains/AIX.h

@@ -67,6 +67,7 @@ class LLVM_LIBRARY_VISIBILITY AIX : public ToolChain {
     return false;
   }
   bool isPICDefaultForced() const override { return true; }
+  bool HasNativeLLVMSupport() const override { return true; }
 
   void
   AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,

clang/lib/Driver/ToolChains/CommonArgs.cpp

@@ -65,24 +65,26 @@ 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();
@@ -96,29 +98,32 @@ static void renderRemarksOptions(const ArgList &Args, ArgStringList &CmdArgs,
 
   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,
@@ -484,14 +489,19 @@ bool tools::isUseSeparateSections(const llvm::Triple &Triple) {
 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.
-    CmdArgs.push_back("-plugin");
+    // 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";
@@ -502,19 +512,23 @@ void tools::addLTOOptions(const ToolChain &ToolChain, const ArgList &Args,
 #endif
 
     SmallString<1024> Plugin;
-    llvm::sys::path::native(
-        Twine(D.Dir) + "/../" CLANG_INSTALL_LIBDIR_BASENAME "/LLVMgold" +
-            Suffix,
-        Plugin);
-    CmdArgs.push_back(Args.MakeArgString(Plugin));
+    llvm::sys::path::native(Twine(D.Dir) +
+                                "/../" CLANG_INSTALL_LIBDIR_BASENAME +
+                                PluginName + Suffix,
+                            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
@@ -523,7 +537,8 @@ void tools::addLTOOptions(const ToolChain &ToolChain, const ArgList &Args,
   // 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
@@ -541,65 +556,73 @@ void tools::addLTOOptions(const ToolChain &ToolChain, const ArgList &Args,
     } else if (A->getOption().matches(options::OPT_O0))
       OOpt = "0";
     if (!OOpt.empty())
-      CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=O") + OOpt));
+      CmdArgs.push_back(
+          Args.MakeArgString(Twine(PluginOptPrefix) + OptLevelPrefix + OOpt));
   }
 
-  if (Args.hasArg(options::OPT_gsplit_dwarf)) {
-    CmdArgs.push_back(
-        Args.MakeArgString(Twine("-plugin-opt=dwo_dir=") +
-            Output.getFilename() + "_dwo"));
-  }
+  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,
@@ -612,29 +635,31 @@ void tools::addLTOOptions(const ToolChain &ToolChain, const ArgList &Args,
   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);
   }
@@ -643,29 +668,29 @@ void tools::addLTOOptions(const ToolChain &ToolChain, const ArgList &Args,
   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,
@@ -1669,10 +1694,12 @@ void tools::addMultilibFlag(bool Enabled, const char *const 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));
@@ -2106,10 +2133,12 @@ bool tools::haveAMDGPUCodeObjectVersionArgument(
 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));

clang/lib/Driver/ToolChains/CommonArgs.h

@@ -190,7 +190,8 @@ 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);
@@ -203,7 +204,8 @@ bool haveAMDGPUCodeObjectVersionArgument(const Driver &D,
 
 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,

clang/test/Driver/lto-aix.c

@@ -0,0 +1,6 @@
+// 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"