[cfe-users] how to stop inlining a recursive template function

[Larry Evans]

With:


http://llvm.org/releases/3.5.0/clang+llvm-3.5.0-x86_64-linux-gnu-ubuntu-14.04.tar.xz

downloaded on:

2014-11-03.2250

and with the compile command:

/dwnlds/llvm/3.5/binary/clang+llvm-3.5.0-x86_64-linux-gnu/bin/clang++ -c
-O0 -g -stdlib=libc++  -std=c++14 -ftemplate-backtrace-limit=0
-I/home/evansl/prog_dev/boost/sandbox/rw/non_variadic_templates
-I/home/evansl/prog_dev/boost/boost-modular/TBoost.Conversion
-I/home/evansl/prog_dev/boost/boost-modular/enums
-I/home/evansl/prog_dev/clang/libcxx/sandbox/libs/composite_storage/include
-I/home/evansl/prog_dev/boost/sandbox/rw/sandbox/lje
-I/home/evansl/prog_dev/boost/boost-releases/ro/boost_1_56_0
-DTYPE_AT_IMPL=0   -ftemplate-depth=324  texpressions.cpp -MMD -o
/tmp/build/clangxx3_5_bin/clang/libcxx/sandbox/libs/gram_stk/sandbox/texpressions.o


I'm getting the error message:

In file included from texpressions.cpp:1:
./texpressions.hpp:1076:36: fatal error: recursive template
instantiation exceeded maximum depth of 324
                boost::trace_scope trace_scope(__FUNCTION__);
                                   ^
./texpressions.hpp:991:19: note: in instantiation of function template
specialization
      'texpressions<my_symbols>::definitions<my_attrs,
composite_storage::type_sequence<texpressions<my_symbols>::def_as<0, 1,
      texpressions<my_symbols>::expr_prefx<op_assoc<0, 0>,

texpressions<my_symbols>::expr_prefx<texpressions<my_symbols>::op_symb<0, 0>>,
      texpressions<my_symbols>::expr_prefx<op_assoc<1, 0>,

texpressions<my_symbols>::expr_prefx<texpressions<my_symbols>::op_symb<0, 1>>,

texpressions<my_symbols>::expr_prefx<texpressions<my_symbols>::op_symb<1, 0>>
> > > > >::read_fold_from<0,
      iter_range<my_symbols<0>::syms,
inp_out_type<my_symbols<0>::syms>::out_type>, def_now_t,

texpressions<my_symbols>::expr_prefx<texpressions<my_symbols>::op_symb<0, 0>>,
      texpressions<my_symbols>::expr_prefx<op_assoc<1, 0>,

texpressions<my_symbols>::expr_prefx<texpressions<my_symbols>::op_symb<0, 1>>,

texpressions<my_symbols>::expr_prefx<texpressions<my_symbols>::op_symb<1, 0>>
> >' requested here
                  read_fold_from
                  ^


Part of the code is:

            template
            < typename LiterlStream
            , vars AnVarble
            , typename DefNow
            >
            bool
          #define READ_FROM_VAR_NOINLINE
          #ifdef READ_FROM_VAR_NOINLINE
            __attribute__((noinline))
          #endif
          read_from
            ( LiterlStream& is
            , DefNow& def_now_inp
            , expr_prefx
              < op_symb
                < symb_kinds::varble_kind
                , AnVarble
                >
              >const& a_expr
            )const
          //#define READ_FROM_VAR_DEF_OUT_CLASS
          #ifdef READ_FROM_VAR_DEF_OUT_CLASS
            ;
          #else
            {
                boost::trace_scope trace_scope(__FUNCTION__);

std::cout<<"read_from(op_varble<"<<AnVarble<<">)"<<std::endl;
                bool
result=read_def_from(is,def_now_inp,this->get_def<AnVarble>());
                return result;
            }
          #endif

The error does not occur when defined(READ_FROM_VAR_DEF_OUT_CLASS).
I was thinking that maybe unrestrained inlining of the code
would be causing the problem, but, as seen from the above
code, even with the __attribute__((noinline)), the error message
occurs.

I'd appreciate any suggestions on how to avoid this fatal error
message about excessive template instantiation.

-regards,
Larry