Re: disruptors of & inventory of Ada compilers and latest their era of ISO8652 compliance

["Dan'l Miller" <optikos@verizon.net>]

On Thursday, May 17, 2018 at 11:49:03 AM UTC-5, Dan'l Miller wrote:
> Wait, GNAT has its own full-fledged IR stage prior to deriving either GENERIC or GIMPLE from that GNAT IR?

On Friday, May 18, 2018 at 6:48:22 AM UTC-5, Lucretia wrote:
> The *tree* packages in GNAT are autogenerated from a *def file, these map onto the C equivalent in the GCC backend so that GNAT can build the trees properly.

The following PowerPoint presentation concurs with you, Luke:
https://www.slideserve.com/reed/the-structure-of-the-gnat-compiler

It also presents a rewording of my “Wait, …” comment above:  GNAT builds an entire Ada-oriented AST-adorned-with-semantics then builds another IR tree using GCC-C-language-compiler constructs.  Effectively GNAT works by effectively translating Ada IR to C IR internally, and then generating machine code from C's IR.  I will need to investigate
1) whether C++ likewise builds its own AST-adorned-with-semantics then builds another IR tree using only C-language constructs
or
2) whether the so-called C-IR tree is actually capable of full-fledged C++-semantic adornment (i.e., whether the so-called C IR would be actually full-fledged C++ IR not lowered to C-only constructs at all) and thus C++ would build only one tree , not GNAT's two.

The GiggleVM drop-in LSP alternative to GIGI in GNAT would have the ability to translate Ada's AST-with-semantic-adornment to either C or C++ constructs in the interface-to-LLVM rear side of Clang.  Occasionally, it might be convenient for GiggleVM to map Ada to directly analogous C++ constructs instead of to C to avoid reinventing the OO wheel from scratch, especially regarding Ada's tagged records vis a vis C++'s vtables.

I need to investigate those def files.  Specifically I'll need to learn:  where is the script/code that reads def files and generates C code or C macros to manipulate the C IR tree?  Perhaps running these def scripts is a major portion of what you refer to as “GCC is a bitch to build” on your GCC build script GitHub README.md.