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.
Turns out that Expression::isConst() actually is much too
pessemistic as it e.g. never regards struct literals as
const.
We should get this fixed to avoid unnecessary heap
allocations for array initialization.
This is just to improve clarity, as it was rather non-obvious
what of the code also applied to classes before.
IrTypeAggr::createInitializerConstant would currently belong in
IrTypeStruct, but this will be refactored anyway.
1. Main include corresponding to .cpp file, if any.
2. DMD and LDC includes.
3. LLVM includes.
4. System includes.
Also updated a few include guards to match the default format.
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.
Before, _d_arraycatT was used to concatenate multiple arrays. That caused an issue when postblit
was called on a struct multiple times. The next code asserted due to the issue:
void main()
{
static struct S
{
int x;
int pad;
this(this)
{
++x;
}
}
auto sarr = new S[1];
auto sarr2 = sarr ~ sarr ~ sarr;
assert(sarr2[0].x == 1);
assert(sarr2[1].x == 1);
assert(sarr2[2].x == 1);
assert(sarr[0].x == 0);
}
