Slangc improvements: help message, downstream error passthrough (#2152)

* Pass through the downstream compiler error messages if they are not recognized.

* Added a help message that is printed on -h, -help, --help.
Added -version as an alias for -v.

* Fixed the bug in -lang option processing.

2 files changed, 220 insertions, 3 deletions

diff --git a/source/compiler-core/slang-downstream-compiler.cpp b/source/compiler-core/slang-downstream-compiler.cpp
index daf31c9eb..1dfaea0a4 100644
--- a/source/compiler-core/slang-downstream-compiler.cpp
+++ b/source/compiler-core/slang-downstream-compiler.cpp
@@ -221,7 +221,7 @@ void DownstreamDiagnostics::requireErrorDiagnostic()
     DownstreamDiagnostic diagnostic;
     diagnostic.reset();
     diagnostic.severity = DownstreamDiagnostic::Severity::Error;
-    diagnostic.text = "Generic error during compilation";
+    diagnostic.text = rawDiagnostics;
 
     // Add the diagnostic
     diagnostics.add(diagnostic);
diff --git a/source/slang/slang-options.cpp b/source/slang/slang-options.cpp
index 07f474c78..5d8d52a09 100644
--- a/source/slang/slang-options.cpp
+++ b/source/slang/slang-options.cpp
@@ -487,6 +487,218 @@ struct OptionsParser
         return SLANG_OK;
     }
 
+    static char const* getHelpText()
+    {
+#ifdef _WIN32
+#define EXECUTABLE_EXTENSION ".exe"
+#else
+#define EXECUTABLE_EXTENSION ""
+#endif
+
+        return
+            "Usage: slangc" EXECUTABLE_EXTENSION " [options...] [--] <input files>\n"
+            "\n"
+            "General options:\n"
+            "\n"
+            "  -D<name>[=<value>], -D <name>[=<value>]: Insert a preprocessor macro.\n"
+            "  -entry <name>: Specify the name of an entry-point function.\n"
+            "    Multiple -entry options may be used in a single invocation.\n"
+            "    If no -entry options are given, compiler will use [shader(...)]\n"
+            "    attributes to detect entry points.\n"
+            "  -h, -help, --help: Print this message.\n"
+            "  -I<path>, -I <path>: Add a path to be used in resolving '#include'\n"
+            "    and 'import' operations.\n"
+            "  -lang <language>: Set the language for the following input files.\n"
+            "    Accepted languages are:\n"
+            "      c, cpp, c++, cxx, slang, glsl, hlsl, cu, cuda\n"
+            "  -matrix-layout-column-major: Set the default matrix layout to column-major.\n"
+            "  -matrix-layout-row-major: Set the default matrix layout to row-major.\n"
+            "  -module-name <name>: Set the module name to use when compiling multiple\n"
+            "    .slang source files into a single module.\n"
+            "  -o <path>: Specify a path where generated output should be written.\n"
+            "    If no -target or -stage is specified, one may be inferred\n"
+            "    from file extension (see File Extensions).\n"
+            "    If multiple -target options and a single -entry are present, each -o\n"
+            "    associates with the first -target to its left.\n"
+            "    Otherwise, if multiple -entry options are present, each -o associates\n"
+            "    with the first -entry to its left, and with the -target that matches\n"
+            "    the one inferred from <path>.\n"
+            "  -profile <profile>[+<capability>...]: Specify the shader profile for code\n"
+            "    generation.\n"
+            "    Accepted profiles are:\n"
+            "      sm_{4_0,4_1,5_0,5_1,6_0,6_1,6_2,6_3,6_4,6_5,6_6}\n"
+            "      glsl_{110,120,130,140,150,330,400,410,420,430,440,450,460}\n"
+            "    Additional profiles that include -stage information:\n"
+            "      {vs,hs,ds,gs,ps}_<version>\n"
+            "    See -capability for information on <capability>\n"
+            "    When multiple -target options are present, each -profile associates\n"
+            "    with the first -target to its left.\n"
+            "  -stage <name>: Specify the stage of an entry-point function.\n"
+            "    Accepted stages are:\n"
+            "      vertex, hull, domain, geometry, fragment, compute,\n"
+            "      raygeneration, intersection, anyhit, closesthit, miss, callable\n"
+            "    When multiple -entry options are present, each -stage associated with\n"
+            "    the first -entry to its left.\n"
+            "    May be omitted if entry-point function has a [shader(...)] attribute;\n"
+            "    otherwise required for each -entry option.\n"
+            "  -target <format>: Specifies the format in which code should be generated.\n"
+            "    Accepted formats are:\n"
+            "      glsl, hlsl, spirv, spirv-assembly, dxbc,\n"
+            "      dxbc-assembly, dxil, dxil-assembly\n"
+            "  -v, -version: Display the build version.\n"
+            "  --: Treat the rest of the command line as input files.\n"
+            "\n"
+            "Target code generation options:\n"
+            "\n"
+            "  -capability <capability>[+<capability>...]: Add optional capabilities\n"
+            "    to a code generation target. See Capabilities below.\n"
+            "  -default-image-format-unknown: Set the format of R/W images with unspecified\n"
+            "    format to 'unknown'. Otherwise try to guess the format.\n"
+            "  -disable-dynamic-dispatch: Disables generating dynamic dispatch code.\n"
+            "  -disable-specialization: Disables generics and specialization pass.\n"
+            "  -fp-mode <mode>, -floating-point-mode <mode>: Set the floating point mode.\n"
+            "    Accepted modes are:\n"
+            "      precise : Disable optimization that could change the output of floating-\n"
+            "        point computations, including around infinities, NaNs, denormalized\n"
+            "        values, and negative zero. Prefer the most precise versions of special\n"
+            "        functions supported by the target.\n"
+            "      fast : Allow optimizations that may change results of floating-point\n"
+            "        computations. Prefer the fastest version of special functions supported\n"
+            "        by the target.\n"
+            "  -g, -g<N>: Include debug information in the generated code, where possible.\n"
+            "    N is the amount of information, 0..3, unspecified means 2\n"
+            "  -line-directive-mode <mode>: Sets how the `#line` directives should be\n"
+            "      produced. Available options are:\n"
+            "        none : Don't emit `#line` directives at all\n"
+            "      If not specified, default behavior is to use C-style `#line` directives\n"
+            "      for HLSL and C/C++ output, and traditional GLSL-style `#line` directives\n"
+            "      for GLSL output.\n"
+            "  -O<N>: Set the optimization level.\n"
+            "    N is the amount of optimization, 0..3, default is 1\n"
+            "  -obfuscate: Remove all source file information from outputs.\n"
+            "\n"
+            "Downstream compiler options:\n"
+            "\n"
+            "  -<compiler>-path: Specify path to a downstream <compiler>\n"
+            "    executable or library. Accepted compilers are:\n"
+            "      fxc (d3dcompiler_47.dll)\n"
+            "      dxc (dxcompiler.*)\n"
+            "      glslang (slang-glslang.*)\n"
+            "      vs = visualstudio (cl.exe)\n"
+            "      clang\n"
+            "      gcc (g++)\n"
+            "      c = cpp = genericcpp\n"
+            "      nvrtc\n"
+            "      llvm\n"
+            "  -default-downstream-compiler <language> <compiler>: Set a default compiler\n"
+            "      for the given language. See -lang for the list of languages.\n"
+            "  -X<compiler> <option>: Pass arguments to downstream <compiler>.\n"
+            "\n"
+            "Compiler debugging/instrumentation options:\n"
+            "\n"
+            "  -dump-ast: Dump the AST to a .slang-ast file next to the input.\n"
+            "  -dump-intermediate-prefix <prefix>: File name prefix for -dump-intermediates \n"
+            "      outputs, default is 'slang-dump-'\n"
+            "  -dump-intermediates: Dump intermediate outputs for debugging.\n"
+            "  -dump-ir: Dump the IR for debugging.\n"
+            "  -dump-ir-ids: Dump the IDs with -dump-ir (debug builds only)\n"
+            "  -dump-repro: Dump a `.slang-repro` file that can be used to reproduce\n"
+            "    a compilation on another machine.\n"
+            "  -dump-repro-on-error: Dump `.slang-repro` file on any compilation error.\n"
+            "  -E, -output-preprocessor: Output the preprocessing result and exit.\n"
+            "  -extract-repro <name>: Extract the repro files into a folder.\n"
+            "  -load-repro <name>\n"
+            "  -load-repro-directory <path>\n"
+            "  -no-codegen: Skip the code generation step, just check the code and\n"
+            "      generate layout.\n"
+            "  -output-includes: Print the hierarchy of the processed source files.\n"
+            "  -pass-through <name>: Pass the input through mostly unmodified to the \n"
+            "      existing compiler <name>. Accepted compilers are:\n"
+            "      fxc, glslang, dxc\n"
+            "  -repro-file-system <name>\n"
+            "  -serial-ir: Serialize the IR between front-end and back-end.\n"
+            "  -skip-codegen: Skip the code generation phase.\n"
+            "  -validate-ir: Validate the IR between the phases.\n"
+            "  -verbose-paths: Display more detailed paths in diagnostic output.\n"
+            "  -verify-debug-serial-ir: Verify IR in the front-end.\n"
+            "\n"
+            "Experimental options (use at your own risk):\n"
+            "\n"
+            "  -emit-spirv-directly: Generate SPIR-V output directly (otherwise through \n"
+            "      GLSL and using the glslang compiler)\n"
+            "  -file-system <fs>: Set the filesystem hook to use for a compile request.\n"
+            "    Accepted file systems:\n"
+            "      default, load-file, os\n"
+            "  -heterogeneous: Output heterogeneity-related code.\n"
+            "  -no-mangle: Do as little mangling of names as possible.\n"
+            "\n"
+            "Internal-use options (use at your own risk):\n"
+            "\n"
+            "  -archive-type <type>: Set the archive type for -save-stdlib. Default is zip.\n"
+            "    Accepted archive types:\n"
+            "      zip, riff, riff-deflate, riff-lz4\n"
+            "  -compile-stdlib: Compile the StdLib from embedded sources.\n"
+            "      Will return a failure if there is already a StdLib available.\n"
+            "  -doc: Write documentation for -compile-stdlib\n"
+            "  -ir-compression <type>: Set compression for IR and AST outputs.\n"
+            "      Accepted compression types:\n"
+            "      none, lite\n"
+            "  -load-stdlib <filename>: Load the StdLib from file.\n"
+            "  -r <name>: reference module <name>\n"
+            "  -save-stdlib <filename>: Save the StdLib modules to an archive file.\n"
+            "  -save-stdlib-bin-source <filename>: Same as -save-stdlib but output\n"
+            "      the data as a C array.\n"
+            "\n"
+            "Deprecated options (allowed but ignored; may be removed in future):\n"
+            "\n"
+            "  -parameter-blocks-use-register-spaces\n"
+            "\n"
+            "File Extensions:\n"
+            "\n"
+            "  A <language>, <format>, and/or <stage> may be inferred from the\n"
+            "  extension of an input or -o path:\n"
+            "\n"
+            "    extension           | language/format | stage\n"
+            "    ====================|=================|======\n"
+            "      .hlsl, .fx        -> hlsl\n"
+            "      .dxbc             -> dxbc\n"
+            "      .dxbc.asm         -> dxbc-assembly\n"
+            "      .dxil             -> dxil\n"
+            "      .dxil.asm         -> dxil-assembly\n"
+            "      .glsl             -> glsl\n"
+            "      .vert             -> glsl            vertex\n"
+            "      .frag             -> glsl            fragment\n"
+            "      .geom             -> glsl            geoemtry\n"
+            "      .tesc             -> glsl            hull\n"
+            "      .tese             -> glsl            domain\n"
+            "      .comp             -> glsl            compute\n"
+            "      .slang            -> slang\n"
+            "      .spv              -> spirv\n"
+            "      .spv.asm          -> spirv-assembly\n"
+            "      .c                -> c\n"
+            "      .cpp, .c++, .cxx  -> c++\n"
+            "      .exe              -> executable\n"
+            "      .dll, .so         -> sharedlibrary\n"
+            "      .cu               -> cuda\n"
+            "      .ptx              -> ptx\n"
+            "      .obj, .o          -> object-code\n"
+            "\n"
+            "Capabilities:\n"
+            "\n"
+            "  A capability describes an optional feature that a target may or\n"
+            "  may not support. When a -capability is specified, the compiler\n"
+            "  may assume that the target supports that capability, and generate\n"
+            "  code accordingly.\n"
+            "  Currently defined capabilities are:\n"
+            "\n"
+            "    spriv_1_{0,1,2,3,4,5}   - minimum supported SPIR-V version\n"
+            "    GL_NV_ray_tracing       - enables the GL_NV_ray_tracing extension\n"
+            "    GL_EXT_ray_tracing      - enables the GL_EXT_ray_tracing extension\n"
+            "\n";
+
+#undef EXECUTABLE_EXTENSION
+    }
+
     SlangResult parse(
         int             argc,
         char const* const*  argv)
@@ -966,7 +1178,7 @@ struct OptionsParser
                     }
                     else
                     {
-                        while (reader.hasArg() && reader.peekValue().startsWith("-"))
+                        while (reader.hasArg() && !reader.peekValue().startsWith("-"))
                         {
                             SLANG_RETURN_ON_FAIL(addInputPath(reader.getValueAndAdvance().getBuffer(), sourceLanguage));
                         }
@@ -1184,10 +1396,15 @@ struct OptionsParser
 
                     _addLibraryReference(requestImpl, &fileStream);
                 }
-                else if (argValue == "-v")
+                else if (argValue == "-v" || argValue == "-version")
                 {
                     sink->diagnoseRaw(Severity::Note, session->getBuildTagString());
                 }
+                else if (argValue == "-h" || argValue == "-help" || argValue == "--help")
+                {
+                    sink->diagnoseRaw(Severity::Note, getHelpText());
+                    return SLANG_FAIL;
+                }
                 else if( argValue == "-emit-spirv-directly" )
                 {
                     getCurrentTarget()->targetFlags |= SLANG_TARGET_FLAG_GENERATE_SPIRV_DIRECTLY;