[HLSL] add -P option for dxc mode.

[python3kgae]

Summary

A new option -P is added for dxc mode.
The format is -P proprecossed_file_name
It will make compile preprocess only and output to proprecossed_file_name.

Internally it will be translated into -E -o proprecossed_file_name.

When -P exists, other output compile option like -Fo will be ignored because compiler will run preprocess only.
A warning will be report if this happened.

[pow2clk]

Mostly just some comments on user output

clang/include/clang/Basic/DiagnosticDriverKinds.td

682

As I read it, "like -Fo" means either "-Fo" or "-o". I think saying that would be less vague.

clang/include/clang/Driver/Options.td

6909

--P is not allowed by DXC

6912

It's not the same as DXC's "-E", which is an unfortunate clash since I love redirecting preprocessed output into less 😒

I realize that we are using some of the clang defined flags to represent the weird DXC ones and in this case that is -E and -o, but this text to the user isn't going to be too helpful to the user who only has access to the DXC -E.

I'm not sure what "used alone" means in this context as you can very much include other flags alongside it

clang/lib/Driver/ToolChains/Clang.cpp

3514

I think we need OPT_o here too in order to capture the full intent since -E doesn't include an output file

[python3kgae]

Rebase and fix merge conflict.

[beanz]

clang/include/clang/Driver/Options.td

6921

This is the same option as _SLASH_P right? Is there a reason not to re-use it?

[python3kgae]

clang/include/clang/Basic/DiagnosticDriverKinds.td

682

dxc mode only accept "-Fo".

clang/include/clang/Driver/Options.td

6909

To work around conflict with clang-cl option
_SLASH_P : CLFlag<"P">, HelpText<"Preprocess to file">;

6921

__SLASH_P is a flag which not accept output file name.
dxc_P is translated into -E -o filename.

-P a.txt will be -E -o a.txt for cc1.

clang/lib/Driver/ToolChains/Clang.cpp

3514

OPT_o has NoXarchOption flag which enabled in dxc mode.
So we don't need OPT_o here.

[python3kgae]

Switch to CLMode -P and -Fi.

[python3kgae]

Not need to send -P and -Fi to cc1.

[python3kgae]

Make a full patch.

[beanz]

clang/include/clang/Basic/DiagnosticDriverKinds.td

672

We should be specific about which flags the user passed that aren't unsupported.

[python3kgae]

Update warning.

[beanz]

clang/lib/Driver/Driver.cpp

5647

Why is this change needed? Didn't we settle on having /P behave the way CL.exe does?

clang/lib/Driver/ToolChains/HLSL.cpp

187

This warning should fire in CL mode too right? Should it not be dxc-specific?

[python3kgae]

clang/lib/Driver/Driver.cpp

5647

Removed.

clang/lib/Driver/ToolChains/HLSL.cpp

187

cl mode report this warning

warning: b.txt: 'linker' input unused [-Wunused-command-line-argument]

when input is

--driver-mode=cl -Fo b.txt  -P -Fi"a.txt"

For HLSL, both -Fo and -Fi should be output.

[beanz]

clang/lib/Driver/ToolChains/HLSL.cpp

187

Then it shouldn’t be named dxc :)

clang/include/clang/Basic/DiagnosticDriverKinds.td

 def err_drv_target_variant_invalid : Error<
   "unsupported '%0' value '%1'; use 'ios-macabi' instead">;
 
 def err_drv_invalid_directx_shader_module : Error<
   "invalid profile : %0">;
 def err_drv_dxc_missing_target_profile : Error<
   "target profile option (-T) is missing">;
 
 def err_drv_invalid_range_dxil_validator_version : Error<
   "invalid validator version : %0\n"
   "Validator version must be less than or equal to current internal version.">;
 def err_drv_invalid_format_dxil_validator_version : Error<
   "invalid validator version : %0\n"
   "Format of validator version is \"<major>.<minor>\" (ex:\"1.4\").">;
 def err_drv_invalid_empty_dxil_validator_version : Error<
   "invalid validator version : %0\n"
   "If validator major version is 0, minor version must also be 0.">;
+def warn_drv_dxc_ignore_output_for_preprocess : Warning<
+  "output compiler options like -Fo ignored with Preprocess">,
+  InGroup<OptionIgnored>;
 
 def warn_drv_sarif_format_unstable : Warning<
   "diagnostic formatting in SARIF mode is currently unstable">,
   InGroup<DiagGroup<"sarif-format-unstable">>;
 
 def err_drv_riscv_unsupported_with_linker_relaxation : Error<
   "%0 is unsupported with RISC-V linker relaxation (-mrelax)">;
 }

clang/include/clang/Driver/Options.td

Values<"ps_6_0, ps_6_1, ps_6_2, ps_6_3, ps_6_4, ps_6_5, ps_6_6, ps_6_7,"
          "ms_6_5, ms_6_6, ms_6_7,"
          "as_6_5, as_6_6, as_6_7">;
 def dxc_D : Option<["--", "/", "-"], "D", KIND_JOINED_OR_SEPARATE>,
   Group<dxc_Group>, Flags<[DXCOption, NoXarchOption]>, Alias<D>;
 def emit_pristine_llvm : DXCFlag<"emit-pristine-llvm">,
   HelpText<"Emit pristine LLVM IR from the frontend by not running any LLVM passes at all."
            "Same as -S + -emit-llvm + -disable-llvm-passes.">;
 def fcgl : DXCFlag<"fcgl">, Alias<emit_pristine_llvm>;
 def enable_16bit_types : DXCFlag<"enable-16bit-types">, Alias<fnative_half_type>,
   HelpText<"Enable 16-bit types and disable min precision types."
            "Available in HLSL 2018 and shader model 6.2.">;
 def hlsl_entrypoint : Option<["-"], "hlsl-entry", KIND_SEPARATE>,
                       Group<dxc_Group>,
                       Flags<[CC1Option]>,
                       MarshallingInfoString<TargetOpts<"HLSLEntry">>,
                       HelpText<"Entry point name for hlsl">;
 def dxc_entrypoint : Option<["--", "/", "-"], "E", KIND_JOINED_OR_SEPARATE>,
                      Group<dxc_Group>,
                      Flags<[DXCOption, NoXarchOption]>,
                      HelpText<"Entry point name">;
+def dxc_P : Option<["--", "/", "-"], "P", KIND_SEPARATE>,
+  Group<dxc_Group>, Flags<[DXCOption, NoXarchOption]>,
+  HelpText<"Preprocess to file, cannot used with other output options like -Fo.">;

clang/lib/Driver/Driver.cpp

const char *Driver::GetNamedOutputPath(Compilation &C, const JobAction &JA,
   std::string BoundArch = OrigBoundArch.str();
   if (is_style_windows(llvm::sys::path::Style::native)) {
     // BoundArch may contains ':', which is invalid in file names on Windows,
     // therefore replace it with '%'.
     std::replace(BoundArch.begin(), BoundArch.end(), ':', '@');
   }
 
   llvm::PrettyStackTraceString CrashInfo("Computing output path");
+
+  // For dxc_P,Output to user requested destination.
+  // When dxc_P is set, -Fo (which is aliased to OPT_o) will be ignored.
+  if (Arg *FinalOutput = C.getArgs().getLastArg(options::OPT_dxc_P))
+    return C.addResultFile(FinalOutput->getValue(), &JA);
+
   // Output to a user requested destination?
   if (AtTopLevel && !isa<DsymutilJobAction>(JA) && !isa<VerifyJobAction>(JA)) {
     if (Arg *FinalOutput = C.getArgs().getLastArg(options::OPT_o))
       return C.addResultFile(FinalOutput->getValue(), &JA);
   }
 
   // For /P, preprocess to file named after BaseInput.
   if (C.getArgs().hasArg(options::OPT__SLASH_P)) {
     assert(AtTopLevel && isa<PreprocessJobAction>(JA));
     StringRef BaseName = llvm::sys::path::filename(BaseInput);
     StringRef NameArg;

clang/lib/Driver/ToolChains/Clang.cpp

static void RenderOpenCLOptions(const ArgList &Args, ArgStringList &CmdArgs,
   }
 }
 
 static void RenderHLSLOptions(const ArgList &Args, ArgStringList &CmdArgs,
                               types::ID InputType) {
   const unsigned ForwardedArguments[] = {options::OPT_dxil_validator_version,
                                          options::OPT_D,
                                          options::OPT_I,
                                          options::OPT_S,
                                          options::OPT_emit_llvm,
                                          options::OPT_disable_llvm_passes,
                                          options::OPT_fnative_half_type,
-                                         options::OPT_hlsl_entrypoint};
+                                         options::OPT_hlsl_entrypoint,
+                                         options::OPT_E,
+                                         options::OPT_dxc_P};
 
   for (const auto &Arg : ForwardedArguments)
     if (const auto *A = Args.getLastArg(Arg))
       A->renderAsInput(Args, CmdArgs);
   // Add the default headers if dxc_no_stdinc is not set.
   if (!Args.hasArg(options::OPT_dxc_no_stdinc))
     CmdArgs.push_back("-finclude-default-header");
   CmdArgs.push_back("-fallow-half-arguments-and-returns");

clang/lib/Driver/ToolChains/HLSL.cpp

HLSLToolChain::TranslateArgs(const DerivedArgList &Args, StringRef BoundArch,
                              Action::OffloadKind DeviceOffloadKind) const {
   DerivedArgList *DAL = new DerivedArgList(Args.getBaseArgs());
 
   const OptTable &Opts = getDriver().getOpts();
 
   for (Arg *A : Args) {
     if (A->getOption().getID() == options::OPT_dxil_validator_version) {
       StringRef ValVerStr = A->getValue();
-      std::string ErrorMsg;
       if (!isLegalValidatorVersion(ValVerStr, getDriver()))
         continue;
     }
     if (A->getOption().getID() == options::OPT_dxc_entrypoint) {
       DAL->AddSeparateArg(nullptr, Opts.getOption(options::OPT_hlsl_entrypoint),
                           A->getValue());
       A->claim();
       continue;
     }
     if (A->getOption().getID() == options::OPT_emit_pristine_llvm) {
       // Translate fcgl into -S -emit-llvm and -disable-llvm-passes.
       DAL->AddFlagArg(nullptr, Opts.getOption(options::OPT_S));
       DAL->AddFlagArg(nullptr, Opts.getOption(options::OPT_emit_llvm));
       DAL->AddFlagArg(nullptr,
                       Opts.getOption(options::OPT_disable_llvm_passes));
       A->claim();
       continue;
     }
+    if (A->getOption().getID() == options::OPT_dxc_P) {
+      // Translate dxc_P into -E and -o.
+      DAL->AddFlagArg(nullptr, Opts.getOption(options::OPT_E));
+      // The -o part is done at clang::driver::Driver::GetNamedOutputPath.
+      A->claim();
+      if (Args.getLastArg(options::OPT_o))
+        getDriver().Diag(diag::warn_drv_dxc_ignore_output_for_preprocess);
+      continue;
+    }
     DAL->append(A);
   }
   // Add default validator version if not set.
   // TODO: remove this once read validator version from validator.
   if (!DAL->hasArg(options::OPT_dxil_validator_version)) {
     const StringRef DefaultValidatorVer = "1.7";
     DAL->AddSeparateArg(nullptr,
                         Opts.getOption(options::OPT_dxil_validator_version),
                         DefaultValidatorVer);
   }
   // FIXME: add validation for enable_16bit_types should be after HLSL 2018 and
   // shader model 6.2.
   return DAL;
 }

clang/test/Driver/dxc_P.hlsl

+// RUN: %clang_dxc -Tlib_6_7 -P a.txt -### %s 2>&1 | FileCheck %s
+// RUN: %clang_dxc -Tlib_6_7  -Fo b.txt -P a.txt -### %s 2>&1 | FileCheck %s --check-prefix=WARNING
+
+// Make sure -P option flag which translated into "-E" + "-o" "a.txt".
+// CHECK:"-E" {{.*}} "-o" "a.txt"
+
+// Make sure got warning when -Fo and -P at same time.
+// WARNING: warning: output compiler options like -Fo ignored with Preprocess [-Woption-ignored]
+// WARNING:"-E" {{.*}} "-o" "a.txt"
+
+