Error while parsing standard type_traits include file

[zillemarco]

When the file type_traits of the standard library is included (#include <type_traits>), the parses throws an AccessViolationException while inside the void Parser::WalkAST() function.

This issue has to do whit the C++ standard library deriving a templated class from another templated class and specializing at least one of the base class' arguements with a template alias.

Following there are a not working example and two fixes:

• not working: here
• first fix: here
• second fix (more interesting since it's only without the template alias): here

[ddobrev]

@zillemarco I can reproduce it without the piece we gave you at #959 (comment) and not with it. Are you absolutely sure you get the crash with this piece applied first?

[zillemarco]

@ddobrev yes I'm positive. I also just tried recompiling CppSharp and my test project to be sure: debugger won't let me put a breakpoint inside Parser::ShouldCompleteType (maybe due to optimization in release build) but it let's me step into Parser.cpp without any warning. Could it be the first thing we discovered (32bit crashing and 64bit not)?

[ddobrev]

@zillemarco precisely. What I meant, in both cases, was - have you tested with 32-bit? In fact, I cannot see how you would test with 64-bit because you'd need to compile Clang first as our binary packages for it on Windows are 32-bit.

[zillemarco]

@ddobrev well..yeah :) I just have a 32bit build :)

[ddobrev]

@zillemarco I have no idea then. I tried at least 2 times back and forth: exit early in the completion, get the crash, execute it, no crash. When I fix the completion, I'm afraid I'll have little choice but to consider this one fixed unless you've provided more information by then.

[zillemarco]

@ddobrev of course I understand. I'll do other tests to see if I can better isolate the problem. I'll compile a 32 bit version of clang so that I can debug that too. Any suggestion on compiling it?

[ddobrev]

@zillemarco you don't need to. Just enable native debugging as I told you earlier and you'll see where in the parser you get the crash.

[zillemarco]

@ddobrev I did but it stops when calling a clang function which at the moment I don't remember the name of. I'll debug it again then to find the exact point.

[ddobrev]

@zillemarco please do and post the stack trace here, it would be useful to know if it's the same as in the case of that array.

[tritao]

About compiling LLVM, see https://github.com/mono/CppSharp/blob/master/docs/BuildingLLVM.md#compiling-using-the-build-script.

If you want to compile in debug mode, do this change in scripts/LLVM.lua:

function get_llvm_configuration_name(debug)
	debug=true
	if debug == true then
		return "Debug"
	end

[ddobrev]

@zillemarco I stand corrected. I had forgotten the piece from the initial bug and it was the one to cause the crash. Unfortunately, this is where the good news ends. I cannot reproduce it either way. Let me tell you what I do to make sure: I copy the contents of https://gist.github.com/zillemarco/e8eb59ff217c27420a114ddea348bfe7 to CSharp.h, then set CSharp.Gen as the starting project and run. What do you do?

[zillemarco]

@ddobrev actually I didn't do that way. I have created another project referencing the CppSharp libraries compiled with the correction you and @tritao told me on Parser::ShouldCompleteType, because that change broke all the tests that are inside the CppSharp solution.

[ddobrev]

@zillemarco I didn't actually run the tests, just the generator. Could you try this way yourself?

[zillemarco]

@ddobrev debugging my test case, I have found the point where the crash happens: when walking the declaration of is_arithmetic it starts evaluating the template arguments of its base class (bool_constant) and it stops when calling Parser::WalkType@2044: c->getSema().RequireCompleteType(...) after Parser::ShouldCompleteType has returned true (so I'm certain that the fix you gave me is being used, otherwise it would have always returned false). More precisely I can see that the last function called is clang::TypeLocVisitor. I have tried to print the stack trace using the kp command on the immediate window, but its the first time I use it and it keeps saying that kp doesn't exist on the current context.

BTW, the exact same thing happened when launching CSharp.Gen as you suggested (but I had to delete the content of the files like AnotherUnit.h and CSharpTemplates.h since the generator started by parsing them first, giving the error on those files)

[tritao]

That looks like the issue is related to type locs. If you want to track it down, you can use this code for dumping then and figuring out what might be wrong: https://gist.github.com/tritao/9c0773b28597f51a033b

Basically you'd need to call it on the offending crashing template argument type loc .