Re: [basic-improvements] try/finally support for c/c++ - more tests

[Mark Mitchell <mark at codesourcery dot com>]

> See elsewhere about resistance compiling libc with a c++ compiler.
I know there's resistance, but frankly I think that's just predjudice.

Compile the bits you need C++ features for in C++.  Avoid stuff that
seems fragile, like virtual bases/virtual functions etc; just use
try/catch and/or destructors if that's all you want.  The functionality
you need has been stable for ages and ages.

I feel strongly that we should not try to bring C++ features into C,
just to avoid having to compile some stuff in libc with G++.  Especially
as similar features may eventually go into ISO C with subtly different
semantics.

> The main problem is that you simply cannot implement cleanups with
> a few calls to a runtime library.  There are data structures that
> the compiler must set up related to how it generated code.
>
> > If we do want to check these patches in, the semantics should be given
> > in terms of translation to (1) above.
I should have said (1) or (2).  I'm comfortable with either formulation,
and you're right that they are subtly different.  If we do (2), we have
to word it cleverly; a literal substitution wouldn't work because local
variables wouldn't be available in S::~S.

> Further, try/catch/rethrow does not express what happens when
> you use goto/break/continue/return to leave the try block.
True.

I don't want to distract us by getting into that; I'm happy to go with
the translation (2) which seems to be what you prefer, if we decide
we absolutely must introduce this feature.

I, however, am far from convinced.

--
Mark Mitchell                mark@codesourcery.com
CodeSourcery, LLC            http://www.codesourcery.com