I found the problem by myself. If one uses XSPP, one must also use Module::Build::WithXSpp to generate XS tyepmap from XSPP typemaps. Otherwise the typemaps are actually not generated.

I'm trying to write a Perl wrapper for my C++ library using XSpp. The typemap looks like this: 
%loadplugin{feature::default_xs_typemap};

%typemap{const std::string&}{parsed}
{
    %precall_code
    {%
        std::string tmp(SvPV($PerlVar));
        $Cvar = tmp;
    %};
};

%typemap{const std::string}{parsed}
{
    %precall_code
    {%
        std::string $Cvar(SvPV($PerlVar));
    %};
};

%typemap{GenoEye::PosType}{simple}
{
    %xs_type{T_IV};
};

%typemap{GenoEye::Page*}{parsed}
{
    %precall_code
    {%
        IV tmp = SvIV(SvRV($PerlVar));
        $CVar = INT2PTR(GenoEye::Page, tmp);
    %};
    %output_code
    {%
        $CVar->ref();
        sv_setref_pv($PerlVar, "GenoEye::Page", $CVar)
    %};
};

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When I do the compile, XS said the "const std::string" is not type mapped: 
Could not find a typemap for C type 'const std::string'.
The following C types are mapped by the current typemap:
'AV *', 'Boolean', 'CV *', 'FILE *', 'FileHandle', 'GenoEye::Page *', 
+'GenoEye::PosType', 'HV *', 'I16', 'I32', 'I8', 'IV', 'InOutStream', 
+'InputStream', 'NV', 'OutputStream', 'PerlIO *', 'Result', 'STRLEN', 
+'SV *', 'SVREF', 'SysRet', 'SysRetLong', 'Time_t *', 'U16', 'U32', 'U
+8', 'UV', 'bool', 'bool_t', 'caddr_t', 'char', 'char *', 'char **', '
+const char *', 'double', 'float', 'int', 'long', 'short', 'size_t', '
+ssize_t', 'time_t', 'unsigned', 'unsigned char', 'unsigned char *', '
+unsigned int', 'unsigned long', 'unsigned long *', 'unsigned short', 
+'void *', 'wchar_t', 'wchar_t *'
 in /usr/bin/perl -MExtUtils::XSpp::Cmd -e xspp -- --typemap=typemap.x
+sp GenoEye_Page.xsp, line 53

[download]
Then I tried to run xspp directly to see the generated XS code. In the TYPEMAP section, it seems most of the typemaps I written is not converted to XS. Why? 
TYPEMAP: <<END
TYPEMAP
GenoEye::Page*    O_OBJECT
GenoEye::PosType    T_IV

INPUT
O_OBJECT
    if( sv_isobject($arg) && (SvTYPE(SvRV($arg)) == SVt_PVMG) )
        $var = ($type)SvIV((SV*)SvRV( $arg ));
    else{
        warn( \"${Package}::$func_name() -- $var is not a blessed SV r
+eference\" );
        XSRETURN_UNDEF;
    }


OUTPUT
O_OBJECT
    sv_setref_pv( $arg, xsp_constructor_class("${my $ntt = $type; $ntt
+ =~ s{^const\s+|[ \t*]+$}{}g; \$ntt}"), (void*)$var );

END

[download]

In reply to xspp did not handle "const string&" typemap by llancet

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