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linkonce-templates bugs
linkonce-templates can not use with betterC code
1.37.0-beta1
ldmd2 -betterC test1.d -I. -linkonce-templates
test1.d
import test2;
@nogc nothrow:
enum ARR = idupArray!();
extern(C) int main(int argc, char** argv){
return 0;
}
test2.d
module test2;
struct Column {
@nogc nothrow:
int id;
}
auto idupArray()(){
if (!__ctfe)
return null;
Column[2] _arr;
return _arr[0..1].idup;
}
import/core/internal/array/duplication.d(39): Error: appending to array in `res ~= cast(immutable(Column))e` requires the GC which is not available with -betterC
remove linkonce-templates
fix the problem.
Thx for the nice test case. This ultimately boils down to __ctfe
being a runtime-constant, so the .idup
call still ends up being codegen'd at the IR level, and then drags in further templates, most notably https://github.com/ldc-developers/ldc/blob/3c21924705aae83f0c16bfe54e673953671afe58/runtime/druntime/src/core/internal/array/duplication.d#L15-L21
-linkonce-templates
per definition emits all instantiated symbols referenced at the IR level, so a _dupCtfe
instantiation too, which is only forward-declared without -linkonce-templates
. In fact, without linker culling getting rid of unreferenced symbols:
ldc2 test1.d -betterC -disable-linker-strip-dead
ld: error: undefined symbol: _D4core8internal5array11duplication__T8_dupCtfeTS5test26ColumnTySQqQmZQBgFNaNbNiNfMAQBkZAyQBa
>>> referenced by test1.d
>>> test1.o:(_D4core8internal5array11duplication__T4_dupTS5test26ColumnTySQqQmZQBcFNaNbNiNeMAQBkZAyQBa)
collect2: error: ld returned 1 exit status