Bizarre Memory leak issue ??? help!

[Stefan Koch]

On Friday, 27 July 2018 at 04:56:01 UTC, Mark wrote:
> Hello,
>
> I am building a toy compiler in D, and during this I ran into a 
> situation.
> It involves checking the header of each function, going through 
> the arguments, and seeing if there is any duplicate identifiers.
>
> I have a python script that feeds a whole bunch of source files 
> that have one error of a specific type each (with an expected 
> error).
>
> The only file that causes this problem is called fnDupArgs.nerf 
> (I called my language nerf).
>
> In my mind, this is a simple check, but for some reason that I 
> can't identify, it causes the entire computers memory to be 
> filled up, causing swapping on the hard drive!
>
> Here is my project: 
> https://github.com/MarkTigchelaar/Nerf-Compiler-2.0
>
> In system_test.py, that test is commented out (un comment it, 
> line 135)
>
> the source of the problem is in the file analyze_semantics.d, 
> on line 36:
>
> void add_func_args_to_local_variable_table(Function* func, ref 
> SymbolTable table) {
>     string[] func_args = func.arg_names.dup;
>     string[] arg_types = table.get_function_args(func.name);
>     if(func_args.length != arg_types.length) {
>         throw new Exception("Number of function variables is 
> not the
>                             same as number of types for same 
> function."); <--compiler error
>     }
>     for(int i = 0; i < func_args.length; i++) {
>         table.add_local_variable(func_args[i], arg_types[i]); 
> <-- line 36
>     }
> }
>
> this calls the symbol tables method in the file symbol_table.d, 
> on line 129:
>
>     final void add_local_variable(string variable, string type) 
> { <-- line 129
>         import fn_header_syntax_errors: duplicate_fn_args;
>         if(!is_declared_variable(variable)) {
>             variable_table[variable] = type;
>             variables_at_scope_level[scope_level] ~= variable;
>         } else {
>             duplicate_fn_args();
>         }
>     }
>
> Now I've been staring at this for an hour and a half. If you 
> leave the one test commented out, everything passes, and all is 
> well.
>
> But if you run that one extra test, it tries to swallow up all 
> the available memory on the computer.
>
> I genuinely have 0 clue why this is happening, could someone 
> help?
> If I can't figure this one out, my compiler will have a hole in 
> it's semantic checking that I don't want.
>
>
> Thanks!

Have you tried using -profile-gc ?