Since the change to the symbol emission strategy, a lot of the
previous attempts to derive the linkage for a symbol from its
AST node has been superfluous. This cleans up all the related
code, as it is really not doing much anymore.
The code to opportunistically internalize symbols is now gone
entirely. It was commented out anyway due to problems with
making it work reliably in the face of the not-so-stable
structure of the AST we get from the frontend (regarding the
modules certain symbols end up in). But in any case internal
linkage woudl also be troublesome for cross-module inlining,
so I gave up on making this work for the time being.
The only (minor) change in the emitted code should be in
.offTi generation, which is untested and disabled by default
anyway (GENERATE_OFFTI).
Turns out that since the change to use DMD's symbol emission
logic a few releases back we didn't actually ever emit code
for the extra modules. Thus, all the effort for the extra
semantic passes went to waste.
If we want to implement DMD-style cross-module inlining, we
need to add the extra semantic3s back in, and then iterate
over all the non-root modules with a codegen visitor that
only emits symbols as available_externally.
We probably won't need the availableExternally members if
we start with a clean design in the new symbol emission
framework. Thus, remove everything in the meantime. This
will make some release builds a bit faster, and should not
negatively affect generated code.
The performance impact should be completely immeasurable,
but the main benefit is that this makes IR dumps slightly
nicer to look at (as the redundant "empty:" labels are
now omitted entirely).
Fixes ABI mismatch when e.g. padding a 28 byte union from a
20 byte member, where previously, an i64 would be emitted,
yielding a 32 byte LLVM struct size on ulong.alignof == 8
platforms.
Test case will follow on the 2.064 branch.
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.
This not only reduces code duplication, but the unification
also enables code a la StructLiteralExp to handle classes
(for CTFE class constant support in 2.063).
This is based on Item 2 of "More Effective C++". In general, the C++ cast operators are more expressive and easy to find,
e.g. by grep. Using const_cast also shuts up some compiler warnings.
1) The last parameter of getGetElementPtr() has type bool. In some instances, a 2 is used as parameter. This is converted to true.
2) Several loops use int instead of unsigned. This causes warning about signed/unsigned mismatch.
Curiously, only Visual C++ complains about this. Nevertheless I think that the warnings should be fixed.
Removed use of dyn_cast, llvm no compiles
without exceptions and rtti by
default. We do need exceptions for the libconfig stuff, but rtti isn't
necessary (anymore).
Debug info needs to be rewritten, as in LLVM 2.7 the format has
completely changed. To have something to look at while rewriting, the
old code has been wrapped inside #ifndef DISABLE_DEBUG_INFO , this means
that you have to define this to compile at the moment.
Updated tango 0.99.9 patch to include updated EH runtime code, which is
needed for LLVM 2.7 as well.
