Method InsertCoroutine

CoroutinesCodeGenerator.cpp:415–709

//-----------------------------------------------------------------------------

void CoroutinesCodeGenerator::InsertCoroutine(const FunctionDecl& fd, const CoroutineBodyStmt* stmt)
{
    mOutputFormatHelper.OpenScope();

    auto& ctx = GetGlobalAST();

    mFSMName = [&] {
        OutputFormatHelper   ofm{};
        CodeGeneratorVariant codeGenerator{ofm};

        // Coroutines can be templates and then we end up with the same FSM name but different template parameters.
        // XXX: This will fail with NTTP's like 3.14
        if(const auto* args = fd.getTemplateSpecializationArgs()) {
            ofm.Append('_');

            for(OnceFalse needsUnderscore{}; const auto& arg : args->asArray()) {
                if(needsUnderscore) {
                    ofm.Append('_');
                }

                codeGenerator->InsertTemplateArg(arg);
            }
        }

        auto str = std::move(ofm.GetString());
        ReplaceAll(str, "<"sv, ""sv);
        ReplaceAll(str, ":"sv, ""sv);
        ReplaceAll(str, ">"sv, ""sv);

        str = BuildTemplateParamObjectName(str);

        if(fd.isOverloadedOperator()) {
            return StrCat(MakeLineColumnName(ctx.getSourceManager(), stmt->getBeginLoc(), "operator_"sv), str);
        } else {
            return StrCat(GetName(fd), str);
        }
    }();

    mFrameName = BuildInternalVarName(StrCat(mFSMName, "Frame"sv));

    // Insert a made up struct which holds the "captured" parameters stored in the coroutine frame
    mASTData.mFrameType          = Struct(mFrameName);
    mASTData.mFrameAccessDeclRef = mkVarDeclRefExpr(CORO_FRAME_NAME, GetFrameType());

    // The coroutine frame starts with two function pointers to the resume and destroy function. See:
    // https://gcc.gnu.org/legacy-ml/gcc-patches/2020-01/msg01096.html:
    // "The ABI mandates that pointers into the coroutine frame point to an area
    // begining with two function pointers (to the resume and destroy functions
    // described below); these are immediately followed by the "promise object"
    // described in the standard."
    //
    // and
    // https://llvm.org/docs/Coroutines.html#id72 "Coroutine Representation"
    auto* resumeFnFd        = Function(hlpResumeFn, VoidTy(), {{CORO_FRAME_NAME, GetFramePointerType()}});
    auto  resumeFnType      = Ptr(resumeFnFd->getType());
    mASTData.mResumeFnField = AddField(hlpResumeFn, resumeFnType);

    auto* destroyFnFd        = Function(hlpDestroyFn, VoidTy(), {{CORO_FRAME_NAME, GetFramePointerType()}});