[LTO][clang] Using Single Dash Consistently when Passing LTO Options

[qiongsiwu1]

Summary

The following three static functions in clang/lib/Driver/ToolChains/CommonArgs.cpp

static void renderRpassOptions(...)
static void renderRemarksOptions(...)
static void renderRemarksHotnessOptions(...)

use --plugin-opt for the plugin option prefix, while the function tools::addLTOOptions uses -plugin-opt. This patch makes sure that we only use -plugin-opt (single dash) everywhere. It is not clear to me that why we decided to use --plugin-opt in https://reviews.llvm.org/D85810. If using --plugin-opt is intended, I'd love to hear the reason and I will close this patch.

We intend to followup this patch with a few other patches that teach clang to pass plugin options to the AIX linker, which uses a different prefix (-bplugin_opt:).

[MaskRay]

I think I want to revert this change. --plugin-opt= is entirely fine with lld and GNU gold/ld... And generally the double-dash long options are preferred.

[qiongsiwu1]

In D134668#3841312, @MaskRay wrote:

I think I want to revert this change. --plugin-opt= is entirely fine with lld and GNU gold/ld... And generally the double-dash long options are preferred.

Sure. What we are aiming at is using single or double dashes consistently, so that when the AIX plugin prefix is introduced, we don't deal with an arbitrary mixture of one or two dashes. I can work on a patch to change all -plugin-opt= to --plugin-opt=. How does having two dashes consistently sound?

[MaskRay]

Err since -plugin-opt= was used a lot of before this change, I think this is fine for consistency.

[qiongsiwu1]

In D134668#3841464, @MaskRay wrote:

Err since -plugin-opt= was used a lot of before this change, I think this is fine for consistency.

Ah ok this sounds good to me as well! Just to make sure I understand, we will need https://reviews.llvm.org/D135400 then. Is this correct?

clang/lib/Driver/ToolChains/CommonArgs.cpp

 
 using namespace clang::driver;
 using namespace clang::driver::tools;
 using namespace clang;
 using namespace llvm::opt;
 
 static void renderRpassOptions(const ArgList &Args, ArgStringList &CmdArgs) {
   if (const Arg *A = Args.getLastArg(options::OPT_Rpass_EQ))
-    CmdArgs.push_back(Args.MakeArgString(Twine("--plugin-opt=-pass-remarks=") +
+    CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=-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("-plugin-opt=-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("-plugin-opt=-pass-remarks-analysis=") + A->getValue()));
 }
 
 static void renderRemarksOptions(const ArgList &Args, ArgStringList &CmdArgs,
                                  const llvm::Triple &Triple,
                                  const InputInfo &Input,
                                  const InputInfo &Output) {
   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 +
+      Args.MakeArgString(Twine("-plugin-opt=opt-remarks-filename=") + F +
                          Twine(".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("-plugin-opt=opt-remarks-passes=") + A->getValue()));
 
   CmdArgs.push_back(Args.MakeArgString(
-      Twine("--plugin-opt=opt-remarks-format=") + Format.data()));
+      Twine("-plugin-opt=opt-remarks-format=") + Format.data()));
 }
 
 static void renderRemarksHotnessOptions(const ArgList &Args,
                                         ArgStringList &CmdArgs) {
   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("-plugin-opt=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()));
+        Twine("-plugin-opt=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());
 }
 

clang/test/Driver/opt-record.c

 
 // Pass-through:
 // RUN: %clang -target x86_64-linux -### -fuse-ld=lld -flto -fdiagnostics-hotness-threshold=100 -fsave-optimization-record -foptimization-record-passes=inline %s 2>&1 | FileCheck %s -check-prefix=CHECK-PASS-A
 // RUN: %clang -target x86_64-linux -### -o FOO -fuse-ld=gold -flto -fdiagnostics-hotness-threshold=100 -fsave-optimization-record -foptimization-record-passes=inline %s 2>&1 | FileCheck %s -check-prefix=CHECK-PASS
 // RUN: %clang -target x86_64-linux -### -o FOO -fuse-ld=lld -flto=thin -fdiagnostics-hotness-threshold=100 -fsave-optimization-record=some-format -foptimization-record-file=FOO.txt %s 2>&1 | FileCheck %s -check-prefix=CHECK-PASS-CUSTOM
 // RUN: %clang -target x86_64-linux -### -o FOO -fuse-ld=lld -flto=thin -fdiagnostics-hotness-threshold=100 -Rpass=inline -Rpass-missed=inline -Rpass-analysis=inline %s 2>&1 | FileCheck %s -check-prefix=CHECK-PASS-RPASS
 // RUN: %clang -target x86_64-linux -### -o FOO -fuse-ld=lld -flto=thin -fdiagnostics-hotness-threshold=auto -Rpass=inline -Rpass-missed=inline -Rpass-analysis=inline %s 2>&1 | FileCheck %s -check-prefix=CHECK-PASS-AUTO
 
-// CHECK-NOPASS-NOT: "--plugin-opt=opt-remarks-filename="
-// CHECK-NOPASS-NOT: "--plugin-opt=opt-remarks-passes=inline"
-// CHECK-NOPASS-NOT: "--plugin-opt=opt-remarks-format=yaml"
-// CHECK-NOPASS-NOT: "--plugin-opt=opt-remarks-hotness-threshold=100"
-
-// CHECK-PASS-A:      "--plugin-opt=opt-remarks-filename=a.out.opt.ld.yaml"
-// CHECK-PASS-A-SAME: "--plugin-opt=opt-remarks-passes=inline"
-// CHECK-PASS-A-SAME: "--plugin-opt=opt-remarks-format=yaml"
-// CHECK-PASS-A-SAME: "--plugin-opt=opt-remarks-hotness-threshold=100"
-
-// CHECK-PASS:      "--plugin-opt=opt-remarks-filename=FOO.opt.ld.yaml"
-// CHECK-PASS-SAME: "--plugin-opt=opt-remarks-passes=inline"
-// CHECK-PASS-SAME: "--plugin-opt=opt-remarks-format=yaml"
-// CHECK-PASS-SAME: "--plugin-opt=opt-remarks-hotness-threshold=100"
-
-// CHECK-PASS-CUSTOM:      "--plugin-opt=opt-remarks-filename=FOO.txt.opt.ld.some-format"
-// CHECK-PASS-CUSTOM-SAME: "--plugin-opt=opt-remarks-format=some-format"
-// CHECK-PASS-CUSTOM-SAME: "--plugin-opt=opt-remarks-hotness-threshold=100"
-
-// CHECK-PASS-RPASS:      "--plugin-opt=-pass-remarks=inline"
-// CHECK-PASS-RPASS-SAME: "--plugin-opt=-pass-remarks-missed=inline"
-// CHECK-PASS-RPASS-SAME: "--plugin-opt=-pass-remarks-analysis=inline"
-// CHECK-PASS-RPASS-SAME: "--plugin-opt=opt-remarks-hotness-threshold=100"
+// CHECK-NOPASS-NOT: "-plugin-opt=opt-remarks-filename="
+// CHECK-NOPASS-NOT: "-plugin-opt=opt-remarks-passes=inline"
+// CHECK-NOPASS-NOT: "-plugin-opt=opt-remarks-format=yaml"
+// CHECK-NOPASS-NOT: "-plugin-opt=opt-remarks-hotness-threshold=100"
+
+// CHECK-PASS-A:      "-plugin-opt=opt-remarks-filename=a.out.opt.ld.yaml"
+// CHECK-PASS-A-SAME: "-plugin-opt=opt-remarks-passes=inline"
+// CHECK-PASS-A-SAME: "-plugin-opt=opt-remarks-format=yaml"
+// CHECK-PASS-A-SAME: "-plugin-opt=opt-remarks-hotness-threshold=100"
+
+// CHECK-PASS:      "-plugin-opt=opt-remarks-filename=FOO.opt.ld.yaml"
+// CHECK-PASS-SAME: "-plugin-opt=opt-remarks-passes=inline"
+// CHECK-PASS-SAME: "-plugin-opt=opt-remarks-format=yaml"
+// CHECK-PASS-SAME: "-plugin-opt=opt-remarks-hotness-threshold=100"
+
+// CHECK-PASS-CUSTOM:      "-plugin-opt=opt-remarks-filename=FOO.txt.opt.ld.some-format"
+// CHECK-PASS-CUSTOM-SAME: "-plugin-opt=opt-remarks-format=some-format"
+// CHECK-PASS-CUSTOM-SAME: "-plugin-opt=opt-remarks-hotness-threshold=100"
+
+// CHECK-PASS-RPASS:      "-plugin-opt=-pass-remarks=inline"
+// CHECK-PASS-RPASS-SAME: "-plugin-opt=-pass-remarks-missed=inline"
+// CHECK-PASS-RPASS-SAME: "-plugin-opt=-pass-remarks-analysis=inline"
+// CHECK-PASS-RPASS-SAME: "-plugin-opt=opt-remarks-hotness-threshold=100"
 
-// CHECK-PASS-AUTO:   "--plugin-opt=opt-remarks-hotness-threshold=auto"
+// CHECK-PASS-AUTO:   "-plugin-opt=opt-remarks-hotness-threshold=auto"