/**
 * Compiler implementation of the $(LINK2 http://www.dlang.org, D programming language)
 *
 * Copyright: Copyright (c) 1999-2016 by Digital Mars, All Rights Reserved
 * Authors: Walter Bright, http://www.digitalmars.com
 * License:   $(LINK2 http://www.boost.org/LICENSE_1_0.txt, Boost License 1.0)
 * Source:    $(DMDSRC cppmangle.d)
 */

module ddmd.cppmangle;

import core.stdc.string;
import core.stdc.stdio;

import ddmd.arraytypes;
import ddmd.declaration;
import ddmd.dstruct;
import ddmd.dsymbol;
import ddmd.dtemplate;
import ddmd.errors;
import ddmd.expression;
import ddmd.func;
import ddmd.globals;
import ddmd.id;
import ddmd.identifier;
import ddmd.mtype;
import ddmd.root.outbuffer;
import ddmd.root.rootobject;
import ddmd.target;
import ddmd.tokens;
import ddmd.visitor;

/* Do mangling for C++ linkage.
 * No attempt is made to support mangling of templates, operator
 * overloading, or special functions.
 *
 * So why don't we use the C++ ABI for D name mangling?
 * Because D supports a lot of things (like modules) that the C++
 * ABI has no concept of. These affect every D mangled name,
 * so nothing would be compatible anyway.
 */
static if (TARGET_LINUX || TARGET_OSX || TARGET_FREEBSD || TARGET_OPENBSD || TARGET_SOLARIS)
{
    /*
     * Follows Itanium C++ ABI 1.86
     */
    extern (C++) final class CppMangleVisitor : Visitor
    {
        alias visit = super.visit;
        Objects components;
        OutBuffer buf;
        bool is_top_level;
        bool components_on;

        void writeBase36(size_t i)
        {
            if (i >= 36)
            {
                writeBase36(i / 36);
                i %= 36;
            }
            if (i < 10)
                buf.writeByte(cast(char)(i + '0'));
            else if (i < 36)
                buf.writeByte(cast(char)(i - 10 + 'A'));
            else
                assert(0);
        }

        bool substitute(RootObject p)
        {
            //printf("substitute %s\n", p ? p.toChars() : null);
            if (components_on)
                for (size_t i = 0; i < components.dim; i++)
                {
                    //printf("    component[%d] = %s\n", i, components[i] ? components[i].toChars() : null);
                    if (p == components[i])
                    {
                        //printf("\tmatch\n");
                        /* Sequence is S_, S0_, .., S9_, SA_, ..., SZ_, S10_, ...
                         */
                        buf.writeByte('S');
                        if (i)
                            writeBase36(i - 1);
                        buf.writeByte('_');
                        return true;
                    }
                }
            return false;
        }

        bool exist(RootObject p)
        {
            //printf("exist %s\n", p ? p.toChars() : null);
            if (components_on)
                for (size_t i = 0; i < components.dim; i++)
                {
                    if (p == components[i])
                    {
                        return true;
                    }
                }
            return false;
        }

        void store(RootObject p)
        {
            //printf("store %s\n", p ? p.toChars() : "null");
            if (components_on)
                components.push(p);
        }

        void source_name(Dsymbol s, bool skipname = false)
        {
            //printf("source_name(%s)\n", s.toChars());
            TemplateInstance ti = s.isTemplateInstance();
            if (ti)
            {
                if (!skipname && !substitute(ti.tempdecl))
                {
                    store(ti.tempdecl);
                    const(char)* name = ti.toAlias().ident.toChars();
                    buf.printf("%d%s", strlen(name), name);
                }
                buf.writeByte('I');
                bool is_var_arg = false;
                for (size_t i = 0; i < ti.tiargs.dim; i++)
                {
                    RootObject o = cast(RootObject)(*ti.tiargs)[i];
                    TemplateParameter tp = null;
                    TemplateValueParameter tv = null;
                    TemplateTupleParameter tt = null;
                    if (!is_var_arg)
                    {
                        TemplateDeclaration td = ti.tempdecl.isTemplateDeclaration();
                        assert(td);
                        tp = (*td.parameters)[i];
                        tv = tp.isTemplateValueParameter();
                        tt = tp.isTemplateTupleParameter();
                    }
                    /*
                     *           <template-arg> ::= <type>            # type or template
                     *                          ::= <expr-primary>   # simple expressions
                     */
                    if (tt)
                    {
                        buf.writeByte('I');
                        is_var_arg = true;
                        tp = null;
                    }
                    if (tv)
                    {
                        // <expr-primary> ::= L <type> <value number> E                   # integer literal
                        if (tv.valType.isintegral())
                        {
                            Expression e = isExpression(o);
                            assert(e);
                            buf.writeByte('L');
                            tv.valType.accept(this);
                            if (tv.valType.isunsigned())
                            {
                                buf.printf("%llu", e.toUInteger());
                            }
                            else
                            {
                                sinteger_t val = e.toInteger();
                                if (val < 0)
                                {
                                    val = -val;
                                    buf.writeByte('n');
                                }
                                buf.printf("%lld", val);
                            }
                            buf.writeByte('E');
                        }
                        else
                        {
                            s.error("Internal Compiler Error: C++ %s template value parameter is not supported", tv.valType.toChars());
                            fatal();
                        }
                    }
                    else if (!tp || tp.isTemplateTypeParameter())
                    {
                        Type t = isType(o);
                        assert(t);
                        t.accept(this);
                    }
                    else if (tp.isTemplateAliasParameter())
                    {
                        Dsymbol d = isDsymbol(o);
                        Expression e = isExpression(o);
                        if (!d && !e)
                        {
                            s.error("Internal Compiler Error: %s is unsupported parameter for C++ template: (%s)", o.toChars());
                            fatal();
                        }
                        if (d && d.isFuncDeclaration())
                        {
                            bool is_nested = d.toParent() && !d.toParent().isModule() && (cast(TypeFunction)d.isFuncDeclaration().type).linkage == LINKcpp;
                            if (is_nested)
                                buf.writeByte('X');
                            buf.writeByte('L');
                            mangle_function(d.isFuncDeclaration());
                            buf.writeByte('E');
                            if (is_nested)
                                buf.writeByte('E');
                        }
                        else if (e && e.op == TOKvar && (cast(VarExp)e).var.isVarDeclaration())
                        {
                            VarDeclaration vd = (cast(VarExp)e).var.isVarDeclaration();
                            buf.writeByte('L');
                            mangle_variable(vd, true);
                            buf.writeByte('E');
                        }
                        else if (d && d.isTemplateDeclaration() && d.isTemplateDeclaration().onemember)
                        {
                            if (!substitute(d))
                            {
                                cpp_mangle_name(d, false);
                            }
                        }
                        else
                        {
                            s.error("Internal Compiler Error: %s is unsupported parameter for C++ template", o.toChars());
                            fatal();
                        }
                    }
                    else
                    {
                        s.error("Internal Compiler Error: C++ templates support only integral value, type parameters, alias templates and alias function parameters");
                        fatal();
                    }
                }
                if (is_var_arg)
                {
                    buf.writeByte('E');
                }
                buf.writeByte('E');
                return;
            }
            else
            {
                const(char)* name = s.ident.toChars();
                buf.printf("%d%s", strlen(name), name);
            }
        }

        void prefix_name(Dsymbol s)
        {
            //printf("prefix_name(%s)\n", s.toChars());
            if (!substitute(s))
            {
                Dsymbol p = s.toParent();
                if (p && p.isTemplateInstance())
                {
                    s = p;
                    if (exist(p.isTemplateInstance().tempdecl))
                    {
                        p = null;
                    }
                    else
                    {
                        p = p.toParent();
                    }
                }
                if (p && !p.isModule())
                {
                    if (p.ident == Id.std && is_initial_qualifier(p))
                        buf.writestring("St");
                    else
                        prefix_name(p);
                }
                if (!(s.ident == Id.std && is_initial_qualifier(s)))
                    store(s);
                source_name(s);
            }
        }

        /* Is s the initial qualifier?
         */
        bool is_initial_qualifier(Dsymbol s)
        {
            Dsymbol p = s.toParent();
            if (p && p.isTemplateInstance())
            {
                if (exist(p.isTemplateInstance().tempdecl))
                {
                    return true;
                }
                p = p.toParent();
            }
            return !p || p.isModule();
        }

        void cpp_mangle_name(Dsymbol s, bool qualified)
        {
            //printf("cpp_mangle_name(%s, %d)\n", s.toChars(), qualified);
            Dsymbol p = s.toParent();
            Dsymbol se = s;
            bool dont_write_prefix = false;
            if (p && p.isTemplateInstance())
            {
                se = p;
                if (exist(p.isTemplateInstance().tempdecl))
                    dont_write_prefix = true;
                p = p.toParent();
            }
            if (p && !p.isModule())
            {
                /* The N..E is not required if:
                 * 1. the parent is 'std'
                 * 2. 'std' is the initial qualifier
                 * 3. there is no CV-qualifier or a ref-qualifier for a member function
                 * ABI 5.1.8
                 */
                if (p.ident == Id.std && is_initial_qualifier(p) && !qualified)
                {
                    if (s.ident == Id.allocator)
                    {
                        buf.writestring("Sa"); // "Sa" is short for ::std::allocator
                        source_name(se, true);
                    }
                    else if (s.ident == Id.basic_string)
                    {
                        components_on = false; // turn off substitutions
                        buf.writestring("Sb"); // "Sb" is short for ::std::basic_string
                        size_t off = buf.offset;
                        source_name(se, true);
                        components_on = true;
                        // Replace ::std::basic_string < char, ::std::char_traits<char>, ::std::allocator<char> >
                        // with Ss
                        //printf("xx: '%.*s'\n", (int)(buf.offset - off), buf.data + off);
                        if (buf.offset - off >= 26 && memcmp(buf.data + off, "IcSt11char_traitsIcESaIcEE".ptr, 26) == 0)
                        {
                            buf.remove(off - 2, 28);
                            buf.insert(off - 2, "Ss".ptr, 2);
                            return;
                        }
                        buf.setsize(off);
                        source_name(se, true);
                    }
                    else if (s.ident == Id.basic_istream || s.ident == Id.basic_ostream || s.ident == Id.basic_iostream)
                    {
                        /* Replace
                         * ::std::basic_istream<char,  std::char_traits<char> > with Si
                         * ::std::basic_ostream<char,  std::char_traits<char> > with So
                         * ::std::basic_iostream<char, std::char_traits<char> > with Sd
                         */
                        size_t off = buf.offset;
                        components_on = false; // turn off substitutions
                        source_name(se, true);
                        components_on = true;
                        //printf("xx: '%.*s'\n", (int)(buf.offset - off), buf.data + off);
                        if (buf.offset - off >= 21 && memcmp(buf.data + off, "IcSt11char_traitsIcEE".ptr, 21) == 0)
                        {
                            buf.remove(off, 21);
                            char[2] mbuf;
                            mbuf[0] = 'S';
                            mbuf[1] = 'i';
                            if (s.ident == Id.basic_ostream)
                                mbuf[1] = 'o';
                            else if (s.ident == Id.basic_iostream)
                                mbuf[1] = 'd';
                            buf.insert(off, mbuf.ptr, 2);
                            return;
                        }
                        buf.setsize(off);
                        buf.writestring("St");
                        source_name(se);
                    }
                    else
                    {
                        buf.writestring("St");
                        source_name(se);
                    }
                }
                else
                {
                    buf.writeByte('N');
                    if (!dont_write_prefix)
                        prefix_name(p);
                    source_name(se);
                    buf.writeByte('E');
                }
            }
            else
                source_name(se);
            store(s);
        }

        void mangle_variable(VarDeclaration d, bool is_temp_arg_ref)
        {
            if (!(d.storage_class & (STCextern | STCgshared)))
            {
                d.error("Internal Compiler Error: C++ static non- __gshared non-extern variables not supported");
                fatal();
            }
            Dsymbol p = d.toParent();
            if (p && !p.isModule()) //for example: char Namespace1::beta[6] should be mangled as "_ZN10Namespace14betaE"
            {
                buf.writestring("_ZN");
                prefix_name(p);
                source_name(d);
                buf.writeByte('E');
            }
            else //char beta[6] should mangle as "beta"
            {
                if (!is_temp_arg_ref)
                {
                    buf.writestring(d.ident.toChars());
                }
                else
                {
                    buf.writestring("_Z");
                    source_name(d);
                }
            }
        }

        void mangle_function(FuncDeclaration d)
        {
            //printf("mangle_function(%s)\n", d.toChars());
            /*
             * <mangled-name> ::= _Z <encoding>
             * <encoding> ::= <function name> <bare-function-type>
             *         ::= <data name>
             *         ::= <special-name>
             */
            TypeFunction tf = cast(TypeFunction)d.type;
            buf.writestring("_Z");
            Dsymbol p = d.toParent();
            if (p && !p.isModule() && tf.linkage == LINKcpp)
            {
                buf.writeByte('N');
                if (d.type.isConst())
                    buf.writeByte('K');
                prefix_name(p);
                // See ABI 5.1.8 Compression
                // Replace ::std::allocator with Sa
                if (buf.offset >= 17 && memcmp(buf.data, "_ZN3std9allocator".ptr, 17) == 0)
                {
                    buf.remove(3, 14);
                    buf.insert(3, "Sa".ptr, 2);
                }
                // Replace ::std::basic_string with Sb
                if (buf.offset >= 21 && memcmp(buf.data, "_ZN3std12basic_string".ptr, 21) == 0)
                {
                    buf.remove(3, 18);
                    buf.insert(3, "Sb".ptr, 2);
                }
                // Replace ::std with St
                if (buf.offset >= 7 && memcmp(buf.data, "_ZN3std".ptr, 7) == 0)
                {
                    buf.remove(3, 4);
                    buf.insert(3, "St".ptr, 2);
                }
                if (buf.offset >= 8 && memcmp(buf.data, "_ZNK3std".ptr, 8) == 0)
                {
                    buf.remove(4, 4);
                    buf.insert(4, "St".ptr, 2);
                }
                if (d.isDtorDeclaration())
                {
                    buf.writestring("D1");
                }
                else
                {
                    source_name(d);
                }
                buf.writeByte('E');
            }
            else
            {
                source_name(d);
            }
            if (tf.linkage == LINKcpp) //Template args accept extern "C" symbols with special mangling
            {
                assert(tf.ty == Tfunction);
                argsCppMangle(tf.parameters, tf.varargs);
            }
        }

        void argsCppMangle(Parameters* parameters, int varargs)
        {
            int paramsCppMangleDg(size_t n, Parameter fparam)
            {
                Type t = fparam.type.merge2();
                if (fparam.storageClass & (STCout | STCref))
                    t = t.referenceTo();
                else if (fparam.storageClass & STClazy)
                {
                    // Mangle as delegate
                    Type td = new TypeFunction(null, t, 0, LINKd);
                    td = new TypeDelegate(td);
                    t = t.merge();
                }
                if (t.ty == Tsarray)
                {
                    // Mangle static arrays as pointers
                    t.error(Loc(), "Internal Compiler Error: unable to pass static array to extern(C++) function.");
                    t.error(Loc(), "Use pointer instead.");
                    fatal();
                    //t = t.nextOf().pointerTo();
                }
                /* If it is a basic, enum or struct type,
                 * then don't mark it const
                 */
                this.is_top_level = true;
                if ((t.ty == Tenum || t.ty == Tstruct || t.ty == Tpointer || t.isTypeBasic()) && t.isConst())
                    t.mutableOf().accept(this);
                else
                    t.accept(this);
                this.is_top_level = false;
                return 0;
            }

            if (parameters)
                Parameter._foreach(parameters, &paramsCppMangleDg);
            if (varargs)
                buf.writestring("z");
            else if (!parameters || !parameters.dim)
                buf.writeByte('v'); // encode ( ) parameters
        }

    public:
        extern (D) this()
        {
            this.components_on = true;
        }

        const(char)* mangleOf(Dsymbol s)
        {
            VarDeclaration vd = s.isVarDeclaration();
            FuncDeclaration fd = s.isFuncDeclaration();
            if (vd)
            {
                mangle_variable(vd, false);
            }
            else if (fd)
            {
                mangle_function(fd);
            }
            else
            {
                assert(0);
            }
            Target.prefixName(&buf, LINKcpp);
            return buf.extractString();
        }

        override void visit(Type t)
        {
            if (t.isImmutable() || t.isShared())
            {
                t.error(Loc(), "Internal Compiler Error: shared or immutable types can not be mapped to C++ (%s)", t.toChars());
            }
            else
            {
                t.error(Loc(), "Internal Compiler Error: unsupported type %s\n", t.toChars());
            }
            fatal(); //Fatal, because this error should be handled in frontend
        }

        override void visit(TypeBasic t)
        {
            /* ABI spec says:
             * v        void
             * w        wchar_t
             * b        bool
             * c        char
             * a        signed char
             * h        unsigned char
             * s        short
             * t        unsigned short
             * i        int
             * j        unsigned int
             * l        long
             * m        unsigned long
             * x        long long, __int64
             * y        unsigned long long, __int64
             * n        __int128
             * o        unsigned __int128
             * f        float
             * d        double
             * e        long double, __float80
             * g        __float128
             * z        ellipsis
             * u <source-name>  # vendor extended type
             */
            char c;
            char p = 0;
            switch (t.ty)
            {
            case Tvoid:
                c = 'v';
                break;
            case Tint8:
                c = 'a';
                break;
            case Tuns8:
                c = 'h';
                break;
            case Tint16:
                c = 's';
                break;
            case Tuns16:
                c = 't';
                break;
            case Tint32:
                c = 'i';
                break;
            case Tuns32:
                c = 'j';
                break;
            case Tfloat32:
                c = 'f';
                break;
            case Tint64:
                c = (Target.c_longsize == 8 ? 'l' : 'x');
                break;
            case Tuns64:
                c = (Target.c_longsize == 8 ? 'm' : 'y');
                break;
            case Tint128:
                c = 'n';
                break;
            case Tuns128:
                c = 'o';
                break;
            case Tfloat64:
                c = 'd';
                break;
            case Tfloat80:
                c = (Target.realsize - Target.realpad == 16) ? 'g' : 'e';
                break;
            case Tbool:
                c = 'b';
                break;
            case Tchar:
                c = 'c';
                break;
            case Twchar:
                c = 't';
                break;
                // unsigned short
            case Tdchar:
                c = 'w';
                break;
                // wchar_t (UTF-32)
            case Timaginary32:
                p = 'G';
                c = 'f';
                break;
            case Timaginary64:
                p = 'G';
                c = 'd';
                break;
            case Timaginary80:
                p = 'G';
                c = 'e';
                break;
            case Tcomplex32:
                p = 'C';
                c = 'f';
                break;
            case Tcomplex64:
                p = 'C';
                c = 'd';
                break;
            case Tcomplex80:
                p = 'C';
                c = 'e';
                break;
            default:
                visit(cast(Type)t);
                return;
            }
            if (t.isImmutable() || t.isShared())
            {
                visit(cast(Type)t);
            }
            if (p || t.isConst())
            {
                if (substitute(t))
                {
                    return;
                }
                else
                {
                    store(t);
                }
            }
            if (t.isConst())
                buf.writeByte('K');
            if (p)
                buf.writeByte(p);
            buf.writeByte(c);
        }

        override void visit(TypeVector t)
        {
            is_top_level = false;
            if (substitute(t))
                return;
            store(t);
            if (t.isImmutable() || t.isShared())
            {
                visit(cast(Type)t);
            }
            if (t.isConst())
                buf.writeByte('K');
            assert(t.basetype && t.basetype.ty == Tsarray);
            assert((cast(TypeSArray)t.basetype).dim);
            //buf.printf("Dv%llu_", ((TypeSArray *)t.basetype).dim.toInteger());// -- Gnu ABI v.4
            buf.writestring("U8__vector"); //-- Gnu ABI v.3
            t.basetype.nextOf().accept(this);
        }

        override void visit(TypeSArray t)
        {
            is_top_level = false;
            if (!substitute(t))
                store(t);
            if (t.isImmutable() || t.isShared())
            {
                visit(cast(Type)t);
            }
            if (t.isConst())
                buf.writeByte('K');
            buf.printf("A%llu_", t.dim ? t.dim.toInteger() : 0);
            t.next.accept(this);
        }

        override void visit(TypeDArray t)
        {
            visit(cast(Type)t);
        }

        override void visit(TypeAArray t)
        {
            visit(cast(Type)t);
        }

        override void visit(TypePointer t)
        {
            is_top_level = false;
            if (substitute(t))
                return;
            if (t.isImmutable() || t.isShared())
            {
                visit(cast(Type)t);
            }
            if (t.isConst())
                buf.writeByte('K');
            buf.writeByte('P');
            t.next.accept(this);
            store(t);
        }

        override void visit(TypeReference t)
        {
            is_top_level = false;
            if (substitute(t))
                return;
            buf.writeByte('R');
            t.next.accept(this);
            store(t);
        }

        override void visit(TypeFunction t)
        {
            is_top_level = false;
            /*
             *  <function-type> ::= F [Y] <bare-function-type> E
             *  <bare-function-type> ::= <signature type>+
             *  # types are possible return type, then parameter types
             */
            /* ABI says:
             "The type of a non-static member function is considered to be different,
             for the purposes of substitution, from the type of a namespace-scope or
             static member function whose type appears similar. The types of two
             non-static member functions are considered to be different, for the
             purposes of substitution, if the functions are members of different
             classes. In other words, for the purposes of substitution, the class of
             which the function is a member is considered part of the type of
             function."

             BUG: Right now, types of functions are never merged, so our simplistic
             component matcher always finds them to be different.
             We should use Type.equals on these, and use different
             TypeFunctions for non-static member functions, and non-static
             member functions of different classes.
             */
            if (substitute(t))
                return;
            buf.writeByte('F');
            if (t.linkage == LINKc)
                buf.writeByte('Y');
            Type tn = t.next;
            if (t.isref)
                tn = tn.referenceTo();
            tn.accept(this);
            argsCppMangle(t.parameters, t.varargs);
            buf.writeByte('E');
            store(t);
        }

        override void visit(TypeDelegate t)
        {
            visit(cast(Type)t);
        }

        override void visit(TypeStruct t)
        {
            const id = t.sym.ident;
            //printf("struct id = '%s'\n", id.toChars());
            char c;
            if (id == Id.__c_long)
                c = 'l';
            else if (id == Id.__c_ulong)
                c = 'm';
            else
                c = 0;
            if (c)
            {
                if (t.isImmutable() || t.isShared())
                {
                    visit(cast(Type)t);
                }
                if (t.isConst())
                {
                    if (substitute(t))
                    {
                        return;
                    }
                    else
                    {
                        store(t);
                    }
                }
                if (t.isConst())
                    buf.writeByte('K');
                buf.writeByte(c);
                return;
            }
            is_top_level = false;
            if (substitute(t))
                return;
            if (t.isImmutable() || t.isShared())
            {
                visit(cast(Type)t);
            }
            if (t.isConst())
                buf.writeByte('K');
            if (!substitute(t.sym))
            {
                cpp_mangle_name(t.sym, t.isConst());
            }
            if (t.isImmutable() || t.isShared())
            {
                visit(cast(Type)t);
            }
            if (t.isConst())
                store(t);
        }

        override void visit(TypeEnum t)
        {
            is_top_level = false;
            if (substitute(t))
                return;
            if (t.isConst())
                buf.writeByte('K');
            if (!substitute(t.sym))
            {
                cpp_mangle_name(t.sym, t.isConst());
            }
            if (t.isImmutable() || t.isShared())
            {
                visit(cast(Type)t);
            }
            if (t.isConst())
                store(t);
        }

        override void visit(TypeClass t)
        {
            if (substitute(t))
                return;
            if (t.isImmutable() || t.isShared())
            {
                visit(cast(Type)t);
            }
            if (t.isConst() && !is_top_level)
                buf.writeByte('K');
            is_top_level = false;
            buf.writeByte('P');
            if (t.isConst())
                buf.writeByte('K');
            if (!substitute(t.sym))
            {
                cpp_mangle_name(t.sym, t.isConst());
            }
            if (t.isConst())
                store(null);
            store(t);
        }

        final const(char)* mangle_typeinfo(Dsymbol s)
        {
            buf.writestring("_ZTI");
            cpp_mangle_name(s, false);
            return buf.extractString();
        }
    }

    extern (C++) const(char)* toCppMangle(Dsymbol s)
    {
        //printf("toCppMangle(%s)\n", s.toChars());
        scope CppMangleVisitor v = new CppMangleVisitor();
        return v.mangleOf(s);
    }

    extern (C++) const(char)* cppTypeInfoMangle(Dsymbol s)
    {
        //printf("cppTypeInfoMangle(%s)\n", s.toChars());
        scope CppMangleVisitor v = new CppMangleVisitor();
        return v.mangle_typeinfo(s);
    }
}
else static if (TARGET_WINDOS)
{
    // Windows DMC and Microsoft Visual C++ mangling
    enum VC_SAVED_TYPE_CNT = 10u;
    enum VC_SAVED_IDENT_CNT = 10u;

    extern (C++) final class VisualCPPMangler : Visitor
    {
        alias visit = super.visit;
        const(char)*[VC_SAVED_IDENT_CNT] saved_idents;
        Type[VC_SAVED_TYPE_CNT] saved_types;

        enum Flags : int
        {
            IS_NOT_TOP_TYPE = 0x1,
            MANGLE_RETURN_TYPE = 0x2,
            IGNORE_CONST = 0x4,
            IS_DMC = 0x8,
        }

        alias IS_NOT_TOP_TYPE = Flags.IS_NOT_TOP_TYPE;
        alias MANGLE_RETURN_TYPE = Flags.MANGLE_RETURN_TYPE;
        alias IGNORE_CONST = Flags.IGNORE_CONST;
        alias IS_DMC = Flags.IS_DMC;

        int flags;
        OutBuffer buf;

        extern (D) this(VisualCPPMangler rvl)
        {
            flags |= (rvl.flags & IS_DMC);
            memcpy(&saved_idents, &rvl.saved_idents, (const(char)*).sizeof * VC_SAVED_IDENT_CNT);
            memcpy(&saved_types, &rvl.saved_types, Type.sizeof * VC_SAVED_TYPE_CNT);
        }

    public:
        extern (D) this(bool isdmc)
        {
            if (isdmc)
            {
                flags |= IS_DMC;
            }
            memset(&saved_idents, 0, (const(char)*).sizeof * VC_SAVED_IDENT_CNT);
            memset(&saved_types, 0, Type.sizeof * VC_SAVED_TYPE_CNT);
        }

        override void visit(Type type)
        {
            if (type.isImmutable() || type.isShared())
            {
                type.error(Loc(), "Internal Compiler Error: shared or immutable types can not be mapped to C++ (%s)", type.toChars());
            }
            else
            {
                type.error(Loc(), "Internal Compiler Error: unsupported type %s\n", type.toChars());
            }
            fatal(); //Fatal, because this error should be handled in frontend
        }

        override void visit(TypeBasic type)
        {
            //printf("visit(TypeBasic); is_not_top_type = %d\n", (int)(flags & IS_NOT_TOP_TYPE));
            if (type.isImmutable() || type.isShared())
            {
                visit(cast(Type)type);
                return;
            }
            if (type.isConst() && ((flags & IS_NOT_TOP_TYPE) || (flags & IS_DMC)))
            {
                if (checkTypeSaved(type))
                    return;
            }
            if ((type.ty == Tbool) && checkTypeSaved(type)) // try to replace long name with number
            {
                return;
            }
            if (!(flags & IS_DMC))
            {
                switch (type.ty)
                {
                case Tint64:
                case Tuns64:
                case Tint128:
                case Tuns128:
                case Tfloat80:
                case Twchar:
                    if (checkTypeSaved(type))
                        return;
                    break;

                default:
                    break;
                }
            }
            mangleModifier(type);
            switch (type.ty)
            {
            case Tvoid:
                buf.writeByte('X');
                break;
            case Tint8:
                buf.writeByte('C');
                break;
            case Tuns8:
                buf.writeByte('E');
                break;
            case Tint16:
                buf.writeByte('F');
                break;
            case Tuns16:
                buf.writeByte('G');
                break;
            case Tint32:
                buf.writeByte('H');
                break;
            case Tuns32:
                buf.writeByte('I');
                break;
            case Tfloat32:
                buf.writeByte('M');
                break;
            case Tint64:
                buf.writestring("_J");
                break;
            case Tuns64:
                buf.writestring("_K");
                break;
            case Tint128:
                buf.writestring("_L");
                break;
            case Tuns128:
                buf.writestring("_M");
                break;
            case Tfloat64:
                buf.writeByte('N');
                break;
            case Tbool:
                buf.writestring("_N");
                break;
            case Tchar:
                buf.writeByte('D');
                break;
            case Tdchar:
                buf.writeByte('I');
                break;
                // unsigned int
            case Tfloat80:
                if (flags & IS_DMC)
                    buf.writestring("_Z"); // DigitalMars long double
                else
                    buf.writestring("_T"); // Intel long double
                break;
            case Twchar:
                if (flags & IS_DMC)
                    buf.writestring("_Y"); // DigitalMars wchar_t
                else
                    buf.writestring("_W"); // Visual C++ wchar_t
                break;
            default:
                visit(cast(Type)type);
                return;
            }
            flags &= ~IS_NOT_TOP_TYPE;
            flags &= ~IGNORE_CONST;
        }

        override void visit(TypeVector type)
        {
            //printf("visit(TypeVector); is_not_top_type = %d\n", (int)(flags & IS_NOT_TOP_TYPE));
            if (checkTypeSaved(type))
                return;
            buf.writestring("T__m128@@"); // may be better as __m128i or __m128d?
            flags &= ~IS_NOT_TOP_TYPE;
            flags &= ~IGNORE_CONST;
        }

        override void visit(TypeSArray type)
        {
            // This method can be called only for static variable type mangling.
            //printf("visit(TypeSArray); is_not_top_type = %d\n", (int)(flags & IS_NOT_TOP_TYPE));
            if (checkTypeSaved(type))
                return;
            // first dimension always mangled as const pointer
            if (flags & IS_DMC)
                buf.writeByte('Q');
            else
                buf.writeByte('P');
            flags |= IS_NOT_TOP_TYPE;
            assert(type.next);
            if (type.next.ty == Tsarray)
            {
                mangleArray(cast(TypeSArray)type.next);
            }
            else
            {
                type.next.accept(this);
            }
        }

        // attention: D int[1][2]* arr mapped to C++ int arr[][2][1]; (because it's more typical situation)
        // There is not way to map int C++ (*arr)[2][1] to D
        override void visit(TypePointer type)
        {
            //printf("visit(TypePointer); is_not_top_type = %d\n", (int)(flags & IS_NOT_TOP_TYPE));
            if (type.isImmutable() || type.isShared())
            {
                visit(cast(Type)type);
                return;
            }
            assert(type.next);
            if (type.next.ty == Tfunction)
            {
                const(char)* arg = mangleFunctionType(cast(TypeFunction)type.next); // compute args before checking to save; args should be saved before function type
                // If we've mangled this function early, previous call is meaningless.
                // However we should do it before checking to save types of function arguments before function type saving.
                // If this function was already mangled, types of all it arguments are save too, thus previous can't save
                // anything if function is saved.
                if (checkTypeSaved(type))
                    return;
                if (type.isConst())
                    buf.writeByte('Q'); // const
                else
                    buf.writeByte('P'); // mutable
                buf.writeByte('6'); // pointer to a function
                buf.writestring(arg);
                flags &= ~IS_NOT_TOP_TYPE;
                flags &= ~IGNORE_CONST;
                return;
            }
            else if (type.next.ty == Tsarray)
            {
                if (checkTypeSaved(type))
                    return;
                mangleModifier(type);
                if (type.isConst() || !(flags & IS_DMC))
                    buf.writeByte('Q'); // const
                else
                    buf.writeByte('P'); // mutable
                if (global.params.is64bit)
                    buf.writeByte('E');
                flags |= IS_NOT_TOP_TYPE;
                mangleArray(cast(TypeSArray)type.next);
                return;
            }
            else
            {
                if (checkTypeSaved(type))
                    return;
                mangleModifier(type);
                if (type.isConst())
                {
                    buf.writeByte('Q'); // const
                }
                else
                {
                    buf.writeByte('P'); // mutable
                }
                if (global.params.is64bit)
                    buf.writeByte('E');
                flags |= IS_NOT_TOP_TYPE;
                type.next.accept(this);
            }
        }

        override void visit(TypeReference type)
        {
            //printf("visit(TypeReference); type = %s\n", type.toChars());
            if (checkTypeSaved(type))
                return;
            if (type.isImmutable() || type.isShared())
            {
                visit(cast(Type)type);
                return;
            }
            buf.writeByte('A'); // mutable
            if (global.params.is64bit)
                buf.writeByte('E');
            flags |= IS_NOT_TOP_TYPE;
            assert(type.next);
            if (type.next.ty == Tsarray)
            {
                mangleArray(cast(TypeSArray)type.next);
            }
            else
            {
                type.next.accept(this);
            }
        }

        override void visit(TypeFunction type)
        {
            const(char)* arg = mangleFunctionType(type);
            if ((flags & IS_DMC))
            {
                if (checkTypeSaved(type))
                    return;
            }
            else
            {
                buf.writestring("$$A6");
            }
            buf.writestring(arg);
            flags &= ~(IS_NOT_TOP_TYPE | IGNORE_CONST);
        }

        override void visit(TypeStruct type)
        {
            const id = type.sym.ident;
            char c;
            if (id == Id.__c_long_double)
                c = 'O'; // VC++ long double
            else if (id == Id.__c_long)
                c = 'J'; // VC++ long
            else if (id == Id.__c_ulong)
                c = 'K'; // VC++ unsigned long
            else
                c = 0;
            if (c)
            {
                if (type.isImmutable() || type.isShared())
                {
                    visit(cast(Type)type);
                    return;
                }
                if (type.isConst() && ((flags & IS_NOT_TOP_TYPE) || (flags & IS_DMC)))
                {
                    if (checkTypeSaved(type))
                        return;
                }
                mangleModifier(type);
                buf.writeByte(c);
            }
            else
            {
                if (checkTypeSaved(type))
                    return;
                //printf("visit(TypeStruct); is_not_top_type = %d\n", (int)(flags & IS_NOT_TOP_TYPE));
                mangleModifier(type);
                if (type.sym.isUnionDeclaration())
                    buf.writeByte('T');
                else
                    buf.writeByte('U');
                mangleIdent(type.sym);
            }
            flags &= ~IS_NOT_TOP_TYPE;
            flags &= ~IGNORE_CONST;
        }

        override void visit(TypeEnum type)
        {
            //printf("visit(TypeEnum); is_not_top_type = %d\n", (int)(flags & IS_NOT_TOP_TYPE));
            if (checkTypeSaved(type))
                return;
            mangleModifier(type);
            buf.writeByte('W');
            switch (type.sym.memtype.ty)
            {
            case Tchar:
            case Tint8:
                buf.writeByte('0');
                break;
            case Tuns8:
                buf.writeByte('1');
                break;
            case Tint16:
                buf.writeByte('2');
                break;
            case Tuns16:
                buf.writeByte('3');
                break;
            case Tint32:
                buf.writeByte('4');
                break;
            case Tuns32:
                buf.writeByte('5');
                break;
            case Tint64:
                buf.writeByte('6');
                break;
            case Tuns64:
                buf.writeByte('7');
                break;
            default:
                visit(cast(Type)type);
                break;
            }
            mangleIdent(type.sym);
            flags &= ~IS_NOT_TOP_TYPE;
            flags &= ~IGNORE_CONST;
        }

        // D class mangled as pointer to C++ class
        // const(Object) mangled as Object const* const
        override void visit(TypeClass type)
        {
            //printf("visit(TypeClass); is_not_top_type = %d\n", (int)(flags & IS_NOT_TOP_TYPE));
            if (checkTypeSaved(type))
                return;
            if (flags & IS_NOT_TOP_TYPE)
                mangleModifier(type);
            if (type.isConst())
                buf.writeByte('Q');
            else
                buf.writeByte('P');
            if (global.params.is64bit)
                buf.writeByte('E');
            flags |= IS_NOT_TOP_TYPE;
            mangleModifier(type);
            buf.writeByte('V');
            mangleIdent(type.sym);
            flags &= ~IS_NOT_TOP_TYPE;
            flags &= ~IGNORE_CONST;
        }

        const(char)* mangleOf(Dsymbol s)
        {
            VarDeclaration vd = s.isVarDeclaration();
            FuncDeclaration fd = s.isFuncDeclaration();
            if (vd)
            {
                mangleVariable(vd);
            }
            else if (fd)
            {
                mangleFunction(fd);
            }
            else
            {
                assert(0);
            }
            return buf.extractString();
        }

    private:
        void mangleFunction(FuncDeclaration d)
        {
            // <function mangle> ? <qualified name> <flags> <return type> <arg list>
            assert(d);
            buf.writeByte('?');
            mangleIdent(d);
            if (d.needThis()) // <flags> ::= <virtual/protection flag> <const/volatile flag> <calling convention flag>
            {
                // Pivate methods always non-virtual in D and it should be mangled as non-virtual in C++
                //printf("%s: isVirtualMethod = %d, isVirtual = %d, vtblIndex = %d, interfaceVirtual = %p\n",
                    //d.toChars(), d.isVirtualMethod(), d.isVirtual(), cast(int)d.vtblIndex, d.interfaceVirtual);
                if (d.isVirtual() && (d.vtblIndex != -1 || d.interfaceVirtual || d.overrideInterface()))
                {
                    switch (d.protection.kind)
                    {
                    case PROTprivate:
                        buf.writeByte('E');
                        break;
                    case PROTprotected:
                        buf.writeByte('M');
                        break;
                    default:
                        buf.writeByte('U');
                        break;
                    }
                }
                else
                {
                    switch (d.protection.kind)
                    {
                    case PROTprivate:
                        buf.writeByte('A');
                        break;
                    case PROTprotected:
                        buf.writeByte('I');
                        break;
                    default:
                        buf.writeByte('Q');
                        break;
                    }
                }
                if (global.params.is64bit)
                    buf.writeByte('E');
                if (d.type.isConst())
                {
                    buf.writeByte('B');
                }
                else
                {
                    buf.writeByte('A');
                }
            }
            else if (d.isMember2()) // static function
            {
                // <flags> ::= <virtual/protection flag> <calling convention flag>
                switch (d.protection.kind)
                {
                case PROTprivate:
                    buf.writeByte('C');
                    break;
                case PROTprotected:
                    buf.writeByte('K');
                    break;
                default:
                    buf.writeByte('S');
                    break;
                }
            }
            else // top-level function
            {
                // <flags> ::= Y <calling convention flag>
                buf.writeByte('Y');
            }
            const(char)* args = mangleFunctionType(cast(TypeFunction)d.type, d.needThis(), d.isCtorDeclaration() || d.isDtorDeclaration());
            buf.writestring(args);
        }

        void mangleVariable(VarDeclaration d)
        {
            // <static variable mangle> ::= ? <qualified name> <protection flag> <const/volatile flag> <type>
            assert(d);
            if (!(d.storage_class & (STCextern | STCgshared)))
            {
                d.error("Internal Compiler Error: C++ static non- __gshared non-extern variables not supported");
                fatal();
            }
            buf.writeByte('?');
            mangleIdent(d);
            assert(!d.needThis());
            if (d.parent && d.parent.isModule()) // static member
            {
                buf.writeByte('3');
            }
            else
            {
                switch (d.protection.kind)
                {
                case PROTprivate:
                    buf.writeByte('0');
                    break;
                case PROTprotected:
                    buf.writeByte('1');
                    break;
                default:
                    buf.writeByte('2');
                    break;
                }
            }
            char cv_mod = 0;
            Type t = d.type;
            if (t.isImmutable() || t.isShared())
            {
                visit(t);
                return;
            }
            if (t.isConst())
            {
                cv_mod = 'B'; // const
            }
            else
            {
                cv_mod = 'A'; // mutable
            }
            if (t.ty != Tpointer)
                t = t.mutableOf();
            t.accept(this);
            if ((t.ty == Tpointer || t.ty == Treference || t.ty == Tclass) && global.params.is64bit)
            {
                buf.writeByte('E');
            }
            buf.writeByte(cv_mod);
        }

        void mangleName(Dsymbol sym, bool dont_use_back_reference = false)
        {
            //printf("mangleName('%s')\n", sym.toChars());
            const(char)* name = null;
            bool is_dmc_template = false;
            if (sym.isDtorDeclaration())
            {
                buf.writestring("?1");
                return;
            }
            if (TemplateInstance ti = sym.isTemplateInstance())
            {
                scope VisualCPPMangler tmp = new VisualCPPMangler((flags & IS_DMC) ? true : false);
                tmp.buf.writeByte('?');
                tmp.buf.writeByte('$');
                tmp.buf.writestring(ti.name.toChars());
                tmp.saved_idents[0] = ti.name.toChars();
                tmp.buf.writeByte('@');
                if (flags & IS_DMC)
                {
                    tmp.mangleIdent(sym.parent, true);
                    is_dmc_template = true;
                }
                bool is_var_arg = false;
                for (size_t i = 0; i < ti.tiargs.dim; i++)
                {
                    RootObject o = (*ti.tiargs)[i];
                    TemplateParameter tp = null;
                    TemplateValueParameter tv = null;
                    TemplateTupleParameter tt = null;
                    if (!is_var_arg)
                    {
                        TemplateDeclaration td = ti.tempdecl.isTemplateDeclaration();
                        assert(td);
                        tp = (*td.parameters)[i];
                        tv = tp.isTemplateValueParameter();
                        tt = tp.isTemplateTupleParameter();
                    }
                    if (tt)
                    {
                        is_var_arg = true;
                        tp = null;
                    }
                    if (tv)
                    {
                        if (tv.valType.isintegral())
                        {
                            tmp.buf.writeByte('$');
                            tmp.buf.writeByte('0');
                            Expression e = isExpression(o);
                            assert(e);
                            if (tv.valType.isunsigned())
                            {
                                tmp.mangleNumber(e.toUInteger());
                            }
                            else if (is_dmc_template)
                            {
                                // NOTE: DMC mangles everything based on
                                // unsigned int
                                tmp.mangleNumber(e.toInteger());
                            }
                            else
                            {
                                sinteger_t val = e.toInteger();
                                if (val < 0)
                                {
                                    val = -val;
                                    tmp.buf.writeByte('?');
                                }
                                tmp.mangleNumber(val);
                            }
                        }
                        else
                        {
                            sym.error("Internal Compiler Error: C++ %s template value parameter is not supported", tv.valType.toChars());
                            fatal();
                        }
                    }
                    else if (!tp || tp.isTemplateTypeParameter())
                    {
                        Type t = isType(o);
                        assert(t);
                        t.accept(tmp);
                    }
                    else if (tp.isTemplateAliasParameter())
                    {
                        Dsymbol d = isDsymbol(o);
                        Expression e = isExpression(o);
                        if (!d && !e)
                        {
                            sym.error("Internal Compiler Error: %s is unsupported parameter for C++ template", o.toChars());
                            fatal();
                        }
                        if (d && d.isFuncDeclaration())
                        {
                            tmp.buf.writeByte('$');
                            tmp.buf.writeByte('1');
                            tmp.mangleFunction(d.isFuncDeclaration());
                        }
                        else if (e && e.op == TOKvar && (cast(VarExp)e).var.isVarDeclaration())
                        {
                            tmp.buf.writeByte('$');
                            if (flags & IS_DMC)
                                tmp.buf.writeByte('1');
                            else
                                tmp.buf.writeByte('E');
                            tmp.mangleVariable((cast(VarExp)e).var.isVarDeclaration());
                        }
                        else if (d && d.isTemplateDeclaration() && d.isTemplateDeclaration().onemember)
                        {
                            Dsymbol ds = d.isTemplateDeclaration().onemember;
                            if (flags & IS_DMC)
                            {
                                tmp.buf.writeByte('V');
                            }
                            else
                            {
                                if (ds.isUnionDeclaration())
                                {
                                    tmp.buf.writeByte('T');
                                }
                                else if (ds.isStructDeclaration())
                                {
                                    tmp.buf.writeByte('U');
                                }
                                else if (ds.isClassDeclaration())
                                {
                                    tmp.buf.writeByte('V');
                                }
                                else
                                {
                                    sym.error("Internal Compiler Error: C++ templates support only integral value, type parameters, alias templates and alias function parameters");
                                    fatal();
                                }
                            }
                            tmp.mangleIdent(d);
                        }
                        else
                        {
                            sym.error("Internal Compiler Error: %s is unsupported parameter for C++ template: (%s)", o.toChars());
                            fatal();
                        }
                    }
                    else
                    {
                        sym.error("Internal Compiler Error: C++ templates support only integral value, type parameters, alias templates and alias function parameters");
                        fatal();
                    }
                }
                name = tmp.buf.extractString();
            }
            else
            {
                name = sym.ident.toChars();
            }
            assert(name);
            if (!is_dmc_template)
            {
                if (dont_use_back_reference)
                {
                    saveIdent(name);
                }
                else
                {
                    if (checkAndSaveIdent(name))
                        return;
                }
            }
            buf.writestring(name);
            buf.writeByte('@');
        }

        // returns true if name already saved
        bool checkAndSaveIdent(const(char)* name)
        {
            foreach (i; 0 .. VC_SAVED_IDENT_CNT)
            {
                if (!saved_idents[i]) // no saved same name
                {
                    saved_idents[i] = name;
                    break;
                }
                if (!strcmp(saved_idents[i], name)) // ok, we've found same name. use index instead of name
                {
                    buf.writeByte(i + '0');
                    return true;
                }
            }
            return false;
        }

        void saveIdent(const(char)* name)
        {
            foreach (i; 0 .. VC_SAVED_IDENT_CNT)
            {
                if (!saved_idents[i]) // no saved same name
                {
                    saved_idents[i] = name;
                    break;
                }
                if (!strcmp(saved_idents[i], name)) // ok, we've found same name. use index instead of name
                {
                    return;
                }
            }
        }

        void mangleIdent(Dsymbol sym, bool dont_use_back_reference = false)
        {
            // <qualified name> ::= <sub-name list> @
            // <sub-name list>  ::= <sub-name> <name parts>
            //                  ::= <sub-name>
            // <sub-name> ::= <identifier> @
            //            ::= ?$ <identifier> @ <template args> @
            //            :: <back reference>
            // <back reference> ::= 0-9
            // <template args> ::= <template arg> <template args>
            //                ::= <template arg>
            // <template arg>  ::= <type>
            //                ::= $0<encoded integral number>
            //printf("mangleIdent('%s')\n", sym.toChars());
            Dsymbol p = sym;
            if (p.toParent() && p.toParent().isTemplateInstance())
            {
                p = p.toParent();
            }
            while (p && !p.isModule())
            {
                mangleName(p, dont_use_back_reference);
                p = p.toParent();
                if (p.toParent() && p.toParent().isTemplateInstance())
                {
                    p = p.toParent();
                }
            }
            if (!dont_use_back_reference)
                buf.writeByte('@');
        }

        void mangleNumber(dinteger_t num)
        {
            if (!num) // 0 encoded as "A@"
            {
                buf.writeByte('A');
                buf.writeByte('@');
                return;
            }
            if (num <= 10) // 5 encoded as "4"
            {
                buf.writeByte(cast(char)(num - 1 + '0'));
                return;
            }
            char[17] buff;
            buff[16] = 0;
            size_t i = 16;
            while (num)
            {
                --i;
                buff[i] = num % 16 + 'A';
                num /= 16;
            }
            buf.writestring(&buff[i]);
            buf.writeByte('@');
        }

        bool checkTypeSaved(Type type)
        {
            if (flags & IS_NOT_TOP_TYPE)
                return false;
            if (flags & MANGLE_RETURN_TYPE)
                return false;
            for (uint i = 0; i < VC_SAVED_TYPE_CNT; i++)
            {
                if (!saved_types[i]) // no saved same type
                {
                    saved_types[i] = type;
                    return false;
                }
                if (saved_types[i].equals(type)) // ok, we've found same type. use index instead of type
                {
                    buf.writeByte(i + '0');
                    flags &= ~IS_NOT_TOP_TYPE;
                    flags &= ~IGNORE_CONST;
                    return true;
                }
            }
            return false;
        }

        void mangleModifier(Type type)
        {
            if (flags & IGNORE_CONST)
                return;
            if (type.isImmutable() || type.isShared())
            {
                visit(type);
                return;
            }
            if (type.isConst())
            {
                if (flags & IS_NOT_TOP_TYPE)
                    buf.writeByte('B'); // const
                else if ((flags & IS_DMC) && type.ty != Tpointer)
                    buf.writestring("_O");
            }
            else if (flags & IS_NOT_TOP_TYPE)
                buf.writeByte('A'); // mutable
        }

        void mangleArray(TypeSArray type)
        {
            mangleModifier(type);
            size_t i = 0;
            Type cur = type;
            while (cur && cur.ty == Tsarray)
            {
                i++;
                cur = cur.nextOf();
            }
            buf.writeByte('Y');
            mangleNumber(i); // count of dimensions
            cur = type;
            while (cur && cur.ty == Tsarray) // sizes of dimensions
            {
                TypeSArray sa = cast(TypeSArray)cur;
                mangleNumber(sa.dim ? sa.dim.toInteger() : 0);
                cur = cur.nextOf();
            }
            flags |= IGNORE_CONST;
            cur.accept(this);
        }

        const(char)* mangleFunctionType(TypeFunction type, bool needthis = false, bool noreturn = false)
        {
            scope VisualCPPMangler tmp = new VisualCPPMangler(this);
            // Calling convention
            if (global.params.is64bit) // always Microsoft x64 calling convention
            {
                tmp.buf.writeByte('A');
            }
            else
            {
                switch (type.linkage)
                {
                case LINKc:
                    tmp.buf.writeByte('A');
                    break;
                case LINKcpp:
                    if (needthis && type.varargs != 1)
                        tmp.buf.writeByte('E'); // thiscall
                    else
                        tmp.buf.writeByte('A'); // cdecl
                    break;
                case LINKwindows:
                    tmp.buf.writeByte('G'); // stdcall
                    break;
                case LINKpascal:
                    tmp.buf.writeByte('C');
                    break;
                default:
                    tmp.visit(cast(Type)type);
                    break;
                }
            }
            tmp.flags &= ~IS_NOT_TOP_TYPE;
            if (noreturn)
            {
                tmp.buf.writeByte('@');
            }
            else
            {
                Type rettype = type.next;
                if (type.isref)
                    rettype = rettype.referenceTo();
                flags &= ~IGNORE_CONST;
                if (rettype.ty == Tstruct || rettype.ty == Tenum)
                {
                    const id = rettype.toDsymbol(null).ident;
                    if (id != Id.__c_long_double && id != Id.__c_long && id != Id.__c_ulong)
                    {
                        tmp.buf.writeByte('?');
                        tmp.buf.writeByte('A');
                    }
                }
                tmp.flags |= MANGLE_RETURN_TYPE;
                rettype.accept(tmp);
                tmp.flags &= ~MANGLE_RETURN_TYPE;
            }
            if (!type.parameters || !type.parameters.dim)
            {
                if (type.varargs == 1)
                    tmp.buf.writeByte('Z');
                else
                    tmp.buf.writeByte('X');
            }
            else
            {
                int mangleParameterDg(size_t n, Parameter p)
                {
                    Type t = p.type;
                    if (p.storageClass & (STCout | STCref))
                    {
                        t = t.referenceTo();
                    }
                    else if (p.storageClass & STClazy)
                    {
                        // Mangle as delegate
                        Type td = new TypeFunction(null, t, 0, LINKd);
                        td = new TypeDelegate(td);
                        t = t.merge();
                    }
                    if (t.ty == Tsarray)
                    {
                        t.error(Loc(), "Internal Compiler Error: unable to pass static array to extern(C++) function.");
                        t.error(Loc(), "Use pointer instead.");
                        assert(0);
                    }
                    tmp.flags &= ~IS_NOT_TOP_TYPE;
                    tmp.flags &= ~IGNORE_CONST;
                    t.accept(tmp);
                    return 0;
                }

                Parameter._foreach(type.parameters, &mangleParameterDg);
                if (type.varargs == 1)
                {
                    tmp.buf.writeByte('Z');
                }
                else
                {
                    tmp.buf.writeByte('@');
                }
            }
            tmp.buf.writeByte('Z');
            const(char)* ret = tmp.buf.extractString();
            memcpy(&saved_idents, &tmp.saved_idents, (const(char)*).sizeof * VC_SAVED_IDENT_CNT);
            memcpy(&saved_types, &tmp.saved_types, Type.sizeof * VC_SAVED_TYPE_CNT);
            return ret;
        }
    }

    extern (C++) const(char)* toCppMangle(Dsymbol s)
    {
        scope VisualCPPMangler v = new VisualCPPMangler(!global.params.mscoff);
        return v.mangleOf(s);
    }

    extern (C++) const(char)* cppTypeInfoMangle(Dsymbol s)
    {
        //printf("cppTypeInfoMangle(%s)\n", s.toChars());
        assert(0);
    }
}
else
{
    static assert(0, "fix this");
}
