path: root/src/main.cpp

/*
 * MRustC - Rust Compiler
 * - By John Hodge (Mutabah/thePowersGang)
 *
 * main.cpp
 * - Compiler Entrypoint
 */
#include <iostream>
#include <iomanip>
#include <string>
#include <set>
#include <version.hpp>
#include <string_view.hpp>
#include "parse/lex.hpp"
#include "parse/parseerror.hpp"
#include "ast/ast.hpp"
#include "ast/crate.hpp"
#include <cstring>
#include <main_bindings.hpp>
#include "resolve/main_bindings.hpp"
#include "hir/main_bindings.hpp"
#include "hir_conv/main_bindings.hpp"
#include "hir_typeck/main_bindings.hpp"
#include "hir_expand/main_bindings.hpp"
#include "mir/main_bindings.hpp"
#include "trans/main_bindings.hpp"
#include "trans/target.hpp"

#include "expand/cfg.hpp"
#include <target_detect.h>	// tools/common/target_detect.h
#include <debug_inner.hpp>

TargetVersion	gTargetVersion = TargetVersion::Rustc1_29;

struct ProgramParams
{
    enum eLastStage {
        STAGE_PARSE,
        STAGE_EXPAND,
        STAGE_RESOLVE,
        STAGE_TYPECK,
        STAGE_BORROWCK,
        STAGE_MIR,
        STAGE_ALL,
    } last_stage = STAGE_ALL;

    ::std::string   infile;
    ::std::string   outfile;
    ::std::string   output_dir = "";
    ::std::string   target = DEFAULT_TARGET_NAME;

    ::std::string   emit_depfile;

    ::AST::Crate::Type  crate_type = ::AST::Crate::Type::Unknown;
    ::std::string   crate_name;
    ::std::string   crate_name_suffix;

    unsigned opt_level = 0;
    bool emit_debug_info = false;

    bool test_harness = false;

    // NOTE: If populated, nothing happens except for loading the target
    ::std::string   target_saveback;

    ::std::vector<const char*> lib_search_dirs;
    ::std::vector<const char*> libraries;
    ::std::map<::std::string, ::std::string>    crate_overrides;    // --extern name=path

    ::std::set< ::std::string> features;

    struct {
        bool disable_mir_optimisations = false;
        bool full_validate = false;
        bool full_validate_early = false;

        bool dump_ast = false;
        bool dump_hir = false;
        bool dump_mir = false;
    } debug;
    struct {
        ::std::string   codegen_type;
        ::std::string   emit_build_command;
    } codegen;

    ProgramParams(int argc, char *argv[]);

    void show_help() const;
};

template <typename Rv, typename Fcn>
Rv CompilePhase(const char *name, Fcn f) {
    DebugTimedPhase timed_phase(name);
    return f();
}
template <typename Fcn>
void CompilePhaseV(const char *name, Fcn f) {
    DebugTimedPhase timed_phase(name);
    f();
}

void init_debug_list()
{
    debug_init_phases("MRUSTC_DEBUG", {
        "Target Load",
        "Parse",
        "LoadCrates",
        "Expand",
        "Dump Expanded",
        "Implicit Crates",

        "Resolve Use",
        "Resolve Index",
        "Resolve Absolute",

        "HIR Lower",

        "Resolve Type Aliases",
        "Resolve Bind",
        "Resolve UFCS Outer",
        "Resolve UFCS paths",
        "Resolve HIR Markings",
        "Constant Evaluate",

        "Typecheck Outer",
        "Typecheck Expressions",

        "Expand HIR Annotate",
        "Expand HIR Closures",
        "Expand HIR Calls",
        "Expand HIR VTables",
        "Expand HIR Reborrows",
        "Expand HIR ErasedType",
        "Typecheck Expressions (validate)",

        "Dump HIR",
        "Lower MIR",
        "MIR Validate",
        "MIR Validate Full Early",
        "Dump MIR",
        "Constant Evaluate Full",
        "MIR Cleanup",
        "MIR Optimise",
        "MIR Validate PO",
        "MIR Validate Full",

        "HIR Serialise",
        "Trans Enumerate",
        "Trans Auto Impls",
        "Trans Monomorph",
        "MIR Optimise Inline",
        "Trans Codegen"
        });
}

/// main!
int main(int argc, char *argv[])
{
    init_debug_list();
    ProgramParams   params(argc, argv);

    // Set up cfg values
    Cfg_SetValue("rust_compiler", "mrustc");
    Cfg_SetValueCb("feature", [&params](const ::std::string& s) {
        return params.features.count(s) != 0;
        });
    CompilePhaseV("Target Load", [&]() {
        Target_SetCfg(params.target);
        });

    if( params.target_saveback != "")
    {
        Target_ExportCurSpec(params.target_saveback);
        return 0;
    }

    if( params.infile == "" )
    {
        ::std::cerr << "No input file passed" << ::std::endl;
        return 1;
    }

    if( params.test_harness )
    {
        Cfg_SetFlag("test");
    }

    Expand_Init();

    try
    {
        // Parse the crate into AST
        AST::Crate crate = CompilePhase<AST::Crate>("Parse", [&]() {
            return Parse_Crate(params.infile);
            });
        crate.m_test_harness = params.test_harness;
        crate.m_crate_name_suffix = params.crate_name_suffix;
        //crate.m_crate_name = params.crate_name;

        if( params.last_stage == ProgramParams::STAGE_PARSE ) {
            return 0;
        }

        // Load external crates.
        CompilePhaseV("LoadCrates", [&]() {
            // Hacky!
            AST::g_crate_overrides = params.crate_overrides;
            for(const auto& ld : params.lib_search_dirs)
            {
                AST::g_crate_load_dirs.push_back(ld);
            }
            crate.load_externs();
            });

        if( params.crate_name != "" ) {
            crate.m_crate_name = params.crate_name;
        }

        // Iterate all items in the AST, applying syntax extensions
        CompilePhaseV("Expand", [&]() {
            Expand(crate);
            });

        if( params.test_harness )
        {
            Expand_TestHarness(crate);
        }

        // Extract the crate type and name from the crate attributes
        auto crate_type = params.crate_type;
        if( crate_type == ::AST::Crate::Type::Unknown ) {
            crate_type = crate.m_crate_type;
        }
        if( crate_type == ::AST::Crate::Type::Unknown ) {
            // Assume to be executable
            crate_type = ::AST::Crate::Type::Executable;
        }
        crate.m_crate_type = crate_type;

        if( crate.m_crate_type == ::AST::Crate::Type::ProcMacro )
        {
            Expand_ProcMacro(crate);
        }

        auto crate_name = params.crate_name;
        if( crate_name == "" )
        {
            crate_name = crate.m_crate_name;
        }
        if( crate_name == "" ) {
            auto s = params.infile.find_last_of('/');
            if( s == ::std::string::npos )
                s = 0;
            else
                s += 1;
            auto e = params.infile.find_first_of('.', s);
            if( e == ::std::string::npos )
                e = params.infile.size() - s;

            crate_name = ::std::string(params.infile.begin() + s, params.infile.begin() + e);
            for(auto& b : crate_name)
            {
                if ('0' <= b && b <= '9') {
                }
                else if ('A' <= b && b <= 'Z') {
                }
                else if (b == '_') {
                }
                else if (b == '-') {
                    b = '_';
                }
                else {
                    // TODO: Error?
                }
            }
        }
        crate.m_crate_name = crate_name;
        if( params.test_harness )
        {
            crate.m_crate_name += "$test";
        }

        if( params.outfile == "" ) {
            switch( crate.m_crate_type )
            {
            case ::AST::Crate::Type::RustLib:
                params.outfile = FMT(params.output_dir << "lib" << crate.m_crate_name << ".rlib");
                break;
            case ::AST::Crate::Type::Executable:
                params.outfile = FMT(params.output_dir << crate.m_crate_name);
                break;
            default:
                params.outfile = FMT(params.output_dir << crate.m_crate_name << ".o");
                break;
            }
            DEBUG("params.outfile = " << params.outfile);
        }

        if( params.debug.dump_ast )
        {
            CompilePhaseV("Dump Expanded", [&]() {
                Dump_Rust( FMT(params.outfile << "_1_ast.rs").c_str(), crate );
                });
        }

        if( params.last_stage == ProgramParams::STAGE_EXPAND ) {
            return 0;
        }

        // Allocator and panic strategies
        CompilePhaseV("Implicit Crates", [&]() {
            if( params.test_harness )
            {
                crate.load_extern_crate(Span(), "test");
            }
            if( crate.m_crate_type == ::AST::Crate::Type::Executable || params.test_harness || crate.m_crate_type == ::AST::Crate::Type::ProcMacro )
            {
                bool allocator_crate_loaded = false;
                RcString    alloc_crate_name;
                bool panic_runtime_loaded = false;
                RcString    panic_crate_name;
                bool panic_runtime_needed = false;
                for(const auto& ec : crate.m_extern_crates)
                {
                    ::std::ostringstream    ss;
                    for(const auto& e : ec.second.m_hir->m_lang_items)
                        ss << e << ",";
                    DEBUG("Looking at lang items from " << ec.first << " : " << ss.str());
                    if(ec.second.m_hir->m_lang_items.count("mrustc-allocator"))
                    {
                        if( allocator_crate_loaded ) {
                            ERROR(Span(), E0000, "Multiple allocator crates loaded - " << alloc_crate_name << " and " << ec.first);
                        }
                        alloc_crate_name = ec.first;
                        allocator_crate_loaded = true;
                    }
                    if(ec.second.m_hir->m_lang_items.count("mrustc-panic_runtime"))
                    {
                        if( panic_runtime_loaded ) {
                            ERROR(Span(), E0000, "Multiple panic_runtime crates loaded - " << panic_crate_name << " and " << ec.first);
                        }
                        panic_crate_name = ec.first;
                        panic_runtime_loaded = true;
                    }
                    if(ec.second.m_hir->m_lang_items.count("mrustc-needs_panic_runtime"))
                    {
                        panic_runtime_needed = true;
                    }
                }
                if( !allocator_crate_loaded )
                {
                    crate.load_extern_crate(Span(), "alloc_system");
                }

                if( panic_runtime_needed && !panic_runtime_loaded )
                {
                    // TODO: Get a panic method from the command line
                    // - Fall back to abort by default, because mrustc doesn't do unwinding yet.
                    crate.load_extern_crate(Span(), "panic_abort");
                }

                // - `mrustc-main` lang item default
                crate.m_lang_items.insert(::std::make_pair( ::std::string("mrustc-main"), ::AST::Path("", {AST::PathNode("main")}) ));
            }
            });

        /// Emit the dependency files
        if( params.emit_depfile != "" )
        {
            // - Iterate all loaded files for modules
            struct PathEnumerator {
                ::std::vector<::std::string> out;
                void visit_module(::AST::Module& mod) {
                    if( mod.m_file_info.path != "!" && mod.m_file_info.path.back() != '/' ) {
                        out.push_back( mod.m_file_info.path );
                    }
                    // TODO: Should we check anon modules?
                    //for(auto& amod : mod.anon_mods()) {
                    //    this->visit_module(*amod);
                    //}
                    for(auto& i : mod.items()) {
                        if(i.data.is_Module()) {
                            this->visit_module(i.data.as_Module());
                        }
                    }
                }
            };
            PathEnumerator pe;
            pe.visit_module(crate.m_root_module);

            ::std::ofstream of { params.emit_depfile };
            // TODO: Escape spaces and colons in these paths
            of << params.outfile << ": " << params.infile;
            for(const auto& mod_path : pe.out)
            {
                of << " " << mod_path;
            }
            of << ::std::endl;

            of << params.outfile << ":";
            // - Iterate all loaded crates files
            for(const auto& ec : crate.m_extern_crates)
            {
                of << " " << ec.second.m_filename;
            }
            // - Iterate all extra files (include! and friends)
        }

        // Resolve names to be absolute names (include references to the relevant struct/global/function)
        // - This does name checking on types and free functions.
        // - Resolves all identifiers/paths to references
        CompilePhaseV("Resolve Use", [&]() {
            Resolve_Use(crate); // - Absolutise and resolve use statements
            });
        CompilePhaseV("Resolve Index", [&]() {
            Resolve_Index(crate); // - Build up a per-module index of avalable names (faster and simpler later resolve)
            });
        CompilePhaseV("Resolve Absolute", [&]() {
            Resolve_Absolutise(crate);  // - Convert all paths to Absolute or UFCS, and resolve variables
            });

        if( params.debug.dump_ast )
        {
            CompilePhaseV("Temp output - Resolved", [&]() {
                Dump_Rust( FMT(params.outfile << "_1_ast.rs").c_str(), crate );
                });
        }

        if( params.last_stage == ProgramParams::STAGE_RESOLVE ) {
            return 0;
        }

        // --------------------------------------
        // HIR Section
        // --------------------------------------
        // Construc the HIR from the AST
        ::HIR::CratePtr hir_crate = CompilePhase< ::HIR::CratePtr>("HIR Lower", [&]() {
            return LowerHIR_FromAST(mv$( crate ));
            });
        // Deallocate the original crate
        crate = ::AST::Crate();
        if( params.debug.dump_hir )
        {
            CompilePhaseV("Dump HIR", [&]() {
                ::std::ofstream os (FMT(params.outfile << "_2_hir.rs"));
                HIR_Dump( os, *hir_crate );
                });
        }

        // Replace type aliases (`type`) into the actual type
        // - Also inserts defaults in trait impls
        CompilePhaseV("Resolve Type Aliases", [&]() {
            ConvertHIR_ExpandAliases(*hir_crate);
            });
        // Set up bindings and other useful information.
        CompilePhaseV("Resolve Bind", [&]() {
            ConvertHIR_Bind(*hir_crate);
            });
        // Enumerate marker impls on types and other useful metadata
        CompilePhaseV("Resolve HIR Markings", [&]() {
            ConvertHIR_Markings(*hir_crate);
            });
        CompilePhaseV("Sort Impls", [&]() {
            ConvertHIR_ResolveUFCS_SortImpls(*hir_crate);
            });
        // Determine what trait to use for <T>::Foo in outer scope
        CompilePhaseV("Resolve UFCS Outer", [&]() {
            ConvertHIR_ResolveUFCS_Outer(*hir_crate);
            });
        if( params.debug.dump_hir ) {
            CompilePhaseV("Dump HIR", [&]() {
                ::std::ofstream os (FMT(params.outfile << "_2_hir.rs"));
                HIR_Dump( os, *hir_crate );
                });
        }
        // Determine what trait to use for <T>::Foo (and does some associated type expansion)
        CompilePhaseV("Resolve UFCS paths", [&]() {
            ConvertHIR_ResolveUFCS(*hir_crate);
            });
        // Basic constant evalulation (intergers/floats only)
        CompilePhaseV("Constant Evaluate", [&]() {
            ConvertHIR_ConstantEvaluate(*hir_crate);
            });

        if( params.debug.dump_hir )
        {
            // DUMP after initial consteval
            CompilePhaseV("Dump HIR", [&]() {
                ::std::ofstream os (FMT(params.outfile << "_2_hir.rs"));
                HIR_Dump( os, *hir_crate );
                });
        }

        // === Type checking ===
        // - This can recurse and call the MIR lower to evaluate constants

        // Check outer items first (types of constants/functions/statics/impls/...)
        // - Doesn't do any expressions except those in types
        CompilePhaseV("Typecheck Outer", [&]() {
            Typecheck_ModuleLevel(*hir_crate);
            });
        // Check the rest of the expressions (including function bodies)
        CompilePhaseV("Typecheck Expressions", [&]() {
            Typecheck_Expressions(*hir_crate);
            });
        // === HIR Expansion ===
        // Annotate how each node's result is used
        CompilePhaseV("Expand HIR Annotate", [&]() {
            HIR_Expand_AnnotateUsage(*hir_crate);
            });
        // - Now that all types are known, closures can be desugared
        CompilePhaseV("Expand HIR Closures", [&]() {
            HIR_Expand_Closures(*hir_crate);
            });
        // - Construct VTables for all traits and impls.
        //  TODO: How early can this be done?
        CompilePhaseV("Expand HIR VTables", [&]() {
            HIR_Expand_VTables(*hir_crate);
            });
        // - And calls can be turned into UFCS
        CompilePhaseV("Expand HIR Calls", [&]() {
            HIR_Expand_UfcsEverything(*hir_crate);
            });
        CompilePhaseV("Expand HIR Reborrows", [&]() {
            HIR_Expand_Reborrows(*hir_crate);
            });
        CompilePhaseV("Expand HIR ErasedType", [&]() {
            HIR_Expand_ErasedType(*hir_crate);
            });
        if( params.debug.dump_hir )
        {
            // DUMP after typecheck (before validation)
            CompilePhaseV("Dump HIR", [&]() {
                ::std::ofstream os (FMT(params.outfile << "_2_hir.rs"));
                HIR_Dump( os, *hir_crate );
                });
        }
        // - Ensure that typeck worked (including Fn trait call insertion etc)
        CompilePhaseV("Typecheck Expressions (validate)", [&]() {
            Typecheck_Expressions_Validate(*hir_crate);
            });

        if( params.last_stage == ProgramParams::STAGE_TYPECK ) {
            return 0;
        }

        // Lower expressions into MIR
        CompilePhaseV("Lower MIR", [&]() {
            HIR_GenerateMIR(*hir_crate);
            });

        if( params.debug.dump_mir )
        {
            // DUMP after generation
            CompilePhaseV("Dump MIR", [&]() {
                ::std::ofstream os (FMT(params.outfile << "_3_mir.rs"));
                MIR_Dump( os, *hir_crate );
                });
        }

        // Validate the MIR
        CompilePhaseV("MIR Validate", [&]() {
            MIR_CheckCrate(*hir_crate);
            });

        // - Expand constants in HIR and virtualise calls
        CompilePhaseV("MIR Cleanup", [&]() {
            MIR_CleanupCrate(*hir_crate);
            });
        if( params.debug.full_validate_early || getenv("MRUSTC_FULL_VALIDATE_PREOPT") )
        {
            CompilePhaseV("MIR Validate Full Early", [&]() {
                MIR_CheckCrate_Full(*hir_crate);
                });
        }

        // Optimise the MIR
        CompilePhaseV("MIR Optimise", [&]() {
            MIR_OptimiseCrate(*hir_crate, params.debug.disable_mir_optimisations);
            });

        if( params.debug.dump_mir )
        {
            // DUMP: After optimisation
            CompilePhaseV("Dump MIR", [&]() {
                ::std::ofstream os (FMT(params.outfile << "_3_mir.rs"));
                MIR_Dump( os, *hir_crate );
                });
        }
        CompilePhaseV("MIR Validate PO", [&]() {
            MIR_CheckCrate(*hir_crate);
            });
        // - Exhaustive MIR validation (follows every code path and checks variable validity)
        // > DEBUGGING ONLY
        CompilePhaseV("MIR Validate Full", [&]() {
            if( params.debug.full_validate || getenv("MRUSTC_FULL_VALIDATE") )
                MIR_CheckCrate_Full(*hir_crate);
            });

        if( params.last_stage == ProgramParams::STAGE_MIR ) {
            return 0;
        }

        // TODO: Pass to mark items that are..
        // - Signature Exportable (public)
        // - MIR Exportable (public generic, #[inline], or used by a either of those)
        // - Require codegen (public or used by an exported function)
        TransOptions    trans_opt;
        trans_opt.mode = params.codegen.codegen_type == "" ? "c" : params.codegen.codegen_type;
        trans_opt.build_command_file = params.codegen.emit_build_command;
        trans_opt.opt_level = params.opt_level;
        for(const char* libdir : params.lib_search_dirs ) {
            // Store these paths for use in final linking.
            hir_crate->m_link_paths.push_back( libdir );
        }
        for(const char* libname : params.libraries ) {
            hir_crate->m_ext_libs.push_back(::HIR::ExternLibrary { libname });
        }
        trans_opt.emit_debug_info = params.emit_debug_info;

        // Generate code for non-generic public items (if requested)
        if( params.test_harness )
        {
            // If the test harness is enabled, override crate type to "Executable"
            crate_type = ::AST::Crate::Type::Executable;
        }

        // TODO: For 1.29 executables/dylibs, add oom/panic shims

        // Enumerate items to be passed to codegen
        TransList items = CompilePhase<TransList>("Trans Enumerate", [&]() {
            switch( crate_type )
            {
            case ::AST::Crate::Type::Unknown:
                ::std::cerr << "BUG? Unknown crate type" << ::std::endl;
                exit(1);
                break;
            case ::AST::Crate::Type::RustLib:
            case ::AST::Crate::Type::RustDylib:
            case ::AST::Crate::Type::CDylib:
                return Trans_Enumerate_Public(*hir_crate);
            case ::AST::Crate::Type::ProcMacro:
                // TODO: proc macros enumerate twice, once as a library (why?) and again as an executable
                return Trans_Enumerate_Public(*hir_crate);
            case ::AST::Crate::Type::Executable:
                return Trans_Enumerate_Main(*hir_crate);
            }
            throw ::std::runtime_error("Invalid crate_type value");
            });
        // - Generate automatic impls (mainly Clone for 1.29)
        CompilePhaseV("Trans Auto Impls", [&]() {
            // TODO: Drop glue generation?
            Trans_AutoImpls(*hir_crate, items);
            });
        // - Generate monomorphised versions of all functions
        CompilePhaseV("Trans Monomorph", [&]() { Trans_Monomorphise_List(*hir_crate, items); });
        // - Do post-monomorph inlining
        CompilePhaseV("MIR Optimise Inline", [&]() { MIR_OptimiseCrate_Inlining(*hir_crate, items); });
        // - Clean up no-unused functions
        //CompilePhaseV("Trans Enumerate Cleanup", [&]() { Trans_Enumerate_Cleanup(*hir_crate, items); });

        switch(crate_type)
        {
        case ::AST::Crate::Type::Unknown:
            throw "";
        case ::AST::Crate::Type::RustLib:
            // Save a loadable HIR dump
            CompilePhaseV("HIR Serialise", [&]() { HIR_Serialise(params.outfile + ".hir", *hir_crate); });
            // Generate a loadable .o
            CompilePhaseV("Trans Codegen", [&]() { Trans_Codegen(params.outfile, CodegenOutput::StaticLibrary, trans_opt, *hir_crate, items, params.outfile + ".hir"); });
            break;
        case ::AST::Crate::Type::RustDylib:
            // Save a loadable HIR dump
            CompilePhaseV("HIR Serialise", [&]() {
                //auto saved_ext_crates = ::std::move(hir_crate->m_ext_crates);
                HIR_Serialise(params.outfile + ".hir", *hir_crate);
                //hir_crate->m_ext_crates = ::std::move(saved_ext_crates);
                });
            // Generate a .so
            CompilePhaseV("Trans Codegen", [&]() { Trans_Codegen(params.outfile, CodegenOutput::DynamicLibrary, trans_opt, *hir_crate, items, params.outfile + ".hir"); });
            break;
        case ::AST::Crate::Type::CDylib:
            // Generate a .so/.dll
            CompilePhaseV("Trans Codegen", [&]() { Trans_Codegen(params.outfile, CodegenOutput::DynamicLibrary, trans_opt, *hir_crate, items, ""); });
            break;
        case ::AST::Crate::Type::ProcMacro: {
            // Needs: An executable (the actual macro handler), metadata (for `extern crate foo;`)

            // 1. Generate code for the plugin itself
            TransList items = CompilePhase<TransList>("Trans Enumerate PM", [&]() { return Trans_Enumerate_Main(*hir_crate); });
            CompilePhaseV("Trans Auto Impls PM", [&]() { Trans_AutoImpls(*hir_crate, items); });
            CompilePhaseV("Trans Monomorph PM", [&]() { Trans_Monomorphise_List(*hir_crate, items); });
            CompilePhaseV("MIR Optimise Inline PM", [&]() { MIR_OptimiseCrate_Inlining(*hir_crate, items); });
            // - Save a very basic HIR dump, making sure that there's no lang items in it (e.g. `mrustc-main`)
            CompilePhaseV("HIR Serialise", [&]() {
                auto saved_lang_items = ::std::move(hir_crate->m_lang_items); hir_crate->m_lang_items.clear();
                HIR_Serialise(params.outfile + ".hir", *hir_crate);
                hir_crate->m_lang_items = ::std::move(saved_lang_items);
                });
            CompilePhaseV("Trans Codegen", [&]() { Trans_Codegen(params.outfile, CodegenOutput::Executable, trans_opt, *hir_crate, items, params.outfile + ".hir"); });
            break; }
        case ::AST::Crate::Type::Executable:
            CompilePhaseV("Trans Codegen", [&]() { Trans_Codegen(params.outfile, CodegenOutput::Executable, trans_opt, *hir_crate, items, ""); });
            break;
        }
    }
    catch(unsigned int) {}
    //catch(const CompileError::Base& e)
    //{
    //    ::std::cerr << "Parser Error: " << e.what() << ::std::endl;
    //    return 2;
    //}
    //catch(const ::std::exception& e)
    //{
    //    ::std::cerr << "Misc Error: " << e.what() << ::std::endl;
    //    return 2;
    //}
    //catch(const char* e)
    //{
    //    ::std::cerr << "Internal Compiler Error: " << e << ::std::endl;
    //    return 2;
    //}

    return 0;
}

ProgramParams::ProgramParams(int argc, char *argv[])
{
    // Hacky command-line parsing
    for( int i = 1; i < argc; i ++ )
    {
        const char* arg = argv[i];

        if( arg[0] != '-' )
        {
            if (this->infile == "")
            {
                this->infile = arg;
            }
            else
            {
                ::std::cerr << "Unexpected free argument" << ::std::endl;
                exit(1);
            }
        }
        else if( arg[1] != '-' )
        {
            arg ++; // eat '-'

            switch( *arg )
            {
            case 'L':
                if( arg[1] == '\0' ) {
                    if( i == argc - 1 ) {
                        ::std::cerr << "Option " << arg << " requires an argument" << ::std::endl;
                        exit(1);
                    }
                    this->lib_search_dirs.push_back( argv[++i] );
                }
                else {
                    this->lib_search_dirs.push_back( arg+1 );
                }
                continue ;
            case 'l':
                if( arg[1] == '\0' ) {
                    if( i == argc - 1 ) {
                        ::std::cerr << "Option " << arg << " requires an argument" << ::std::endl;
                        exit(1);
                    }
                    this->libraries.push_back( argv[++i] );
                }
                else {
                    this->libraries.push_back( arg+1 );
                }
                continue ;
            case 'C': {
                ::std::string optname;
                ::std::string optval;
                if( arg[1] == '\0' ) {
                    if( i == argc - 1) {
                        ::std::cerr << "Option " << arg << " requires an argument" << ::std::endl;
                        exit(1);
                    }
                    optname = argv[++i];
                }
                else {
                    optname = arg+1;
                }
                auto eq_pos = optname.find('=');
                if( eq_pos != ::std::string::npos ) {
                    optval = optname.substr(eq_pos+1);
                    optname.resize(eq_pos);
                }
                auto get_optval = [&]() {
                    if( eq_pos == ::std::string::npos ) {
                        ::std::cerr << "Flag -Z " << optname << " requires an argument" << ::std::endl;
                        exit(1);
                    }
                    };
                //auto no_optval = [&]() {
                //    if(eq_pos != ::std::string::npos) {
                //        ::std::cerr << "Flag -Z " << optname << " doesn't take an argument" << ::std::endl;
                //        exit(1);
                //    }
                //    };

                if( optname == "emit-build-command" ) {
                    get_optval();
                    this->codegen.emit_build_command = optval;
                }
                else if( optname == "codegen-type" ) {
                    get_optval();
                    this->codegen.codegen_type = optval;
                }
                else if( optname == "emit-depfile" ) {
                    get_optval();
                    this->emit_depfile = optval;
                }
                else {
                    ::std::cerr << "Unknown codegen option: '" << optname << "'" << ::std::endl;
                    exit(1);
                }
                } continue;
            case 'Z': {
                ::std::string optname;
                ::std::string optval;
                if( arg[1] == '\0' ) {
                    if( i == argc - 1) {
                        ::std::cerr << "Option " << arg << " requires an argument" << ::std::endl;
                        exit(1);
                    }
                    optname = argv[++i];
                }
                else {
                    optname = arg+1;
                }
                auto eq_pos = optname.find('=');
                if( eq_pos != ::std::string::npos ) {
                    optval = optname.substr(eq_pos+1);
                    optname.resize(eq_pos);
                }
                auto get_optval = [&]() {
                    if( eq_pos == ::std::string::npos ) {
                        ::std::cerr << "Flag -Z " << optname << " requires an argument" << ::std::endl;
                        exit(1);
                    }
                    };
                auto no_optval = [&]() {
                    if(eq_pos != ::std::string::npos) {
                        ::std::cerr << "Flag -Z " << optname << " doesn't take an argument" << ::std::endl;
                        exit(1);
                    }
                    };

                if( optname == "disable-mir-opt" ) {
                    no_optval();
                    this->debug.disable_mir_optimisations = true;
                }
                else if( optname == "full-validate" ) {
                    no_optval();
                    this->debug.full_validate = true;
                }
                else if( optname == "full-validate-early" ) {
                    no_optval();
                    this->debug.full_validate_early = true;
                }
                else if( optname == "dump-ast" ) {
                    no_optval();
                    this->debug.dump_ast = true;
                }
                else if( optname == "dump-hir" ) {
                    no_optval();
                    this->debug.dump_hir = true;
                }
                else if( optname == "dump-mir" ) {
                    no_optval();
                    this->debug.dump_mir = true;
                }
                else if( optname == "stop-after" ) {
                    get_optval();
                    if( optval == "parse" )
                        this->last_stage = STAGE_PARSE;
                    else if( optval == "expand" )
                        this->last_stage = STAGE_EXPAND;
                    else if( optval == "resolve" )
                        this->last_stage = STAGE_RESOLVE;
                    else if( optval == "typeck" )
                        this->last_stage = STAGE_TYPECK;
                    else if( optval == "mir" )
                        this->last_stage = STAGE_MIR;
                    else {
                        ::std::cerr << "Unknown argument to -Z stop-after - '" << optval << "'" << ::std::endl;
                        exit(1);
                    }
                }
                else {
                    ::std::cerr << "Unknown debug option: '" << optname << "'" << ::std::endl;
                    exit(1);
                }
                } continue;

            default:
                // Fall through to the for loop below
                break;
            }

            for( ; *arg; arg ++ )
            {
                switch(*arg)
                {
                // "-o <file>" : Set output file
                case 'o':
                    if( i == argc - 1 ) {
                        ::std::cerr << "Option -" << *arg << " requires an argument" << ::std::endl;
                        exit(1);
                    }
                    this->outfile = argv[++i];
                    break;
                case 'O':
                    this->opt_level = 2;
                    break;
                case 'g':
                    this->emit_debug_info = true;
                    break;
                default:
                    ::std::cerr << "Unknown option: '-" << *arg << "'" << ::std::endl;
                    exit(1);
                }
            }
        }
        else
        {
            if( strcmp(arg, "--help") == 0 ) {
                this->show_help();
                exit(0);
            }
            else if( strcmp(arg, "--version" ) == 0 ) {
                const char* rustc_target = "unknown";
                switch(gTargetVersion)
                {
                case TargetVersion::Rustc1_19:  rustc_target = "1.19";  break;
                case TargetVersion::Rustc1_29:  rustc_target = "1.29";  break;
                }
                // NOTE: Starts the version with "rustc 1.29.100" so build scripts don't get confused
                ::std::cout << "rustc " << rustc_target << ".100 (mrustc " << Version_GetString() << ")" << ::std::endl;
                ::std::cout << "- Build time: " << gsVersion_BuildTime << ::std::endl;
                ::std::cout << "- Commit: " << gsVersion_GitHash << (gbVersion_GitDirty ? " (dirty tree)" : "") << ::std::endl;
                exit(0);
            }
            // --out-dir <dir>  >> Set the output directory for automatically-named files
            else if( strcmp(arg, "--out-dir") == 0) {
                if (i == argc - 1) {
                    ::std::cerr << "Flag " << arg << " requires an argument" << ::std::endl;
                    exit(1);
                }
                this->output_dir = argv[++i];
                if( this->output_dir != "" && this->output_dir.back() != '/' )
                {
                    this->output_dir += '/';
                }
            }
            // --extern <name>=<path>   >> Override the file to load for `extern crate <name>;`
            else if( strcmp(arg, "--extern") == 0 ) {
                if( i == argc - 1 ) {
                    ::std::cerr << "Option " << arg << " requires an argument" << ::std::endl;
                    exit(1);
                }
                const char* desc = argv[++i];
                const char* pos = ::std::strchr(desc, '=');
                if( pos == nullptr ) {
                    ::std::cerr << "--extern takes an argument of the format name=path" << ::std::endl;
                    exit(1);
                }

                auto name = ::std::string(desc, pos);
                auto path = ::std::string(pos+1);
                this->crate_overrides.insert(::std::make_pair( mv$(name), mv$(path) ));
            }
            // --crate-tag <name>  >> Specify a version/identifier suffix for the crate
            else if( strcmp(arg, "--crate-tag") == 0 ) {
                if( i == argc - 1 ) {
                    ::std::cerr << "Flag " << arg << " requires an argument" << ::std::endl;
                    exit(1);
                }
                const char* name_str = argv[++i];
                this->crate_name_suffix = name_str;
            }
            // --crate-name <name>  >> Specify the crate name (overrides `#![crate_name="<name>"]`)
            else if( strcmp(arg, "--crate-name") == 0 ) {
                if( i == argc - 1 ) {
                    ::std::cerr << "Flag --crate-name requires an argument" << ::std::endl;
                    exit(1);
                }
                const char* name_str = argv[++i];
                this->crate_name = name_str;
            }
            // `--crate-type <name>`    - Specify the crate type (overrides `#![crate_type="<name>"]`)
            else if( strcmp(arg, "--crate-type") == 0 ) {
                if( i == argc - 1 ) {
                    ::std::cerr << "Flag --crate-type requires an argument" << ::std::endl;
                    exit(1);
                }
                const char* type_str = argv[++i];

                if( strcmp(type_str, "rlib") == 0 ) {
                    this->crate_type = ::AST::Crate::Type::RustLib;
                }
                else if( strcmp(type_str, "dylib") == 0 ) {
                    this->crate_type = ::AST::Crate::Type::RustDylib;
                }
                else if( strcmp(type_str, "bin") == 0 ) {
                    this->crate_type = ::AST::Crate::Type::Executable;
                }
                else if( strcmp(type_str, "proc-macro") == 0 ) {
                    this->crate_type = ::AST::Crate::Type::ProcMacro;
                }
                else {
                    ::std::cerr << "Unknown value for --crate-type" << ::std::endl;
                    exit(1);
                }
            }
            // `--cfg <flag>`
            // `--cfg <var>=<value>`
            else if( strcmp(arg, "--cfg") == 0 ) {
                if( i == argc - 1 ) {
                    ::std::cerr << "Flag --cfg requires an argument" << ::std::endl;
                    exit(1);
                }
                char* opt_and_val = argv[++i];
                if( char* p = strchr(opt_and_val, '=') ) {
                    *p = '\0';
                    const char* opt = opt_and_val;
                    const char* val = p + 1;
                    // TODO: Correctly parse the values.
                    // - Value should be a double-quoted string.
                    if( ::std::strcmp(opt, "feature") == 0 ) {
                        this->features.insert( ::std::string(val) );
                    }
                    else {
                        if( val[0] == '"' ) {
                            // TODO: Something cleaner than this.
                            ::std::string   s = val+1;
                            assert(s.back() == '"');
                            s.pop_back();
                            Cfg_SetValue(opt, s);
                        }
                        else {
                            Cfg_SetValue(opt, val);
                        }
                    }
                }
                else {
                    Cfg_SetFlag(opt_and_val);
                }
            }
            // `--target <triple>`  - Override the default compiler target
            else if( strcmp(arg, "--target") == 0 ) {
                if (i == argc - 1) {
                    ::std::cerr << "Flag " << arg << " requires an argument" << ::std::endl;
                    exit(1);
                }
                this->target = argv[++i];
            }
            else if( strcmp(arg, "--dump-target-spec") == 0 ) {
                if (i == argc - 1) {
                    ::std::cerr << "Flag " << arg << " requires an argument" << ::std::endl;
                    exit(1);
                }
                this->target_saveback = argv[++i];
            }
            else if( strcmp(arg, "--test") == 0 ) {
                this->test_harness = true;
            }
            else {
                ::std::cerr << "Unknown option '" << arg << "'" << ::std::endl;
                exit(1);
            }
        }
    }


    if( const auto* a = getenv("MRUSTC_TARGET_VER") )
    {
        if( strcmp(a, "1.19") == 0 ) {
            gTargetVersion = TargetVersion::Rustc1_19;
        }
        else if( strcmp(a, "1.29") == 0 ) {
            gTargetVersion = TargetVersion::Rustc1_29;
        }
        else {
        }
    }

    if( const auto* a = getenv("MRUSTC_DUMP") )
    {
        while( a[0] )
        {
            const char* end = strchr(a, ':');

            ::stdx::string_view  s;
            if( end ) {
                s = ::stdx::string_view { a, end };
                a = end + 1;
            }
            else {
                end = a + strlen(a);
                s = ::stdx::string_view { a, end };
                a = end;
            }

            if( s == "" ) {
                // Ignore
            }
            else if( s == "ast" ) {
                this->debug.dump_ast = true;
            }
            else if( s == "hir" ) {
                this->debug.dump_hir = true;
            }
            else if( s == "mir" ) {
                this->debug.dump_mir = true;
            }
            else {
                ::std::cerr << "Unknown option in $MRUSTC_DUMP '" << s << "'" << ::std::endl;
                // - No terminate, just warn
            }
        }
    }
}
void ProgramParams::show_help() const
{
    ::std::cout <<
        "USAGE: mrustc <sourcefile>\n"
        "\n"
        "OPTIONS:\n"
        "-L <dir>           : Search for crate files (.hir) in this directory\n"
        "-o <filename>      : Write compiler output (library or executable) to this file\n"
        "-O                 : Enable optimistion\n"
        "-g                 : Emit debugging information\n"
        "--out-dir <dir>    : Specify the output directory (alternative to `-o`)\n"
        "--extern <crate>=<path>\n"
        "                   : Specify the path for a given crate (instead of searching for it)\n"
        "--crate-tag <str>  : Specify a suffix for symbols and output files\n"
        "--crate-name <str> : Override/set the crate name\n"
        "--crate-type <ty>  : Override/set the crate type (rlib, bin, proc-macro)\n"
        "--cfg flag         : Set a boolean #[cfg]/cfg! flag\n"
        "--cfg flag=\"val\"   : Set a string #[cfg]/cfg! flag\n"
        "--target <name>    : Compile code for the given target\n"
        "--test             : Generate a unit test executable\n"
        "-C <option>        : Code-generation options\n"
        "-Z <option>        : Debugging/experiemental options\n"
        ;
}