This commit fundamentally changes the way symbol emission in
LDC works: Previously, whenever a declaration was used in some
way, the compiler would check whether it actually needs to be
defined in the currently processed module, based only on the
symbol itself. This lack of contextual information proved to
be a major problem in correctly handling emission of templates
(see e.g. #454).
Now, the DtoResolve…() family of functions and similar only
ever declare the symbols, and definition is handled by doing
a single pass over Module::members for the root module. This
is the same strategy that DMD uses as well, which should
also reduce the maintainance burden down the road (which is
important as during the last few releases, there was pretty
much always a symbol emission related problem slowing us
down).
Our old approach might have been a bit better tuned w.r.t.
avoiding emission of unneeded template instances, but 2.064
will bring improvements here (DMD: FuncDeclaration::toObjFile).
Barring such issues, the change shoud also marginally improve
compile times because of declarations no longer being emitted
when they are not needed.
In the future, we should also consider refactoring the code
so that it no longer directly accesses Dsymbol::ir but uses
wrapper functions that ensure that the appropriate
DtoResolve…() function has been called.
GitHub: Fixes#454.
LDC_never_inline is a complementary intrinsic to LDC_allow_inline.
It tells the LLVM optimizer to never inline a function. This can be
useful if inlining creates incorrect code.
A possible application is core.thread.getStackTop().
Having two functions is not pretty, but shorter than messing
around with a custom context object, and much, MUCH better than
requiring a lot of changes to the rest of the code base.
This reverts commit c4adbedcc, which would have fixed the
problem at its roots, but caused strange template function
attribute inference failures in D-YAML, presumably due to
the different order of semantic3 execution on the templates.
