As for SAM wrappers, the bytecode sequence
new A
dup
new B
dup
invokespecial B.<init>
invokespecial A.<init>
breaks the inliner, so instead we do
new B
dup
invokespecial B.<init>
store x
new A
dup
load x
invokespecial A.<init>
Otherwise, the cached instances cannot be reused for different wrapped
types. Also, if the wrapped type is regenerated during inlining, the
inliner would produce a call to a nonexistent constructor that takes the
regenerated type as an argument.
To avoid bytecode sequences like
new _1Kt$sam$i$java_lang_Runnable$0
dup
new _1Kt$f$1
dup
invokespecial _1Kt$f$1.<init>()V
invokespecial _1Kt$sam$i$java_lang_Runnable$0.<init>(...)V
as the different order of `new` and `<init>` confuses the inliner.
Namely, anonymous objects defined in lambdas that have all captured
variables as loose fields instead of a single reference to the parent.
The question is, when a lambda inside an inline function defines an
anonymous object, and that object is not regenerated during codegen for
the inline function itself, but then has to be regenerated at call site
anyway, do we use an outer `this` or loose capture fields? For example,
before KT-28064:
inline fun f1(g: () -> Unit) = object { g() }
// -> f1$1 { $g: () -> Unit }
inline fun f2(g: () -> Unit) = f1 { object { g() } }
// -> f2$$inlined$f1$1 { $g: () -> Unit }
// f2$$inlined$f1$1$lambda$1 { this$0: f2$$inlined$f1$1 }
inline fun f3(g: () -> Unit) = f2 { object { g() } }
// -> f3$$inlined$f2$1 { $g: () -> Unit }
// f3$$inlined$f2$1$1 { this$0: f3$$inlined$f2$1 }
// f3$$inlined$f2$1$1$lambda$1 { this$0: f3$$inlined$f2$1$1 }
After KT-28064:
inline fun f2(g: () -> Unit) = f1 { object { g() } }
// -> f2$$inlined$f1$1 { $g: () -> Unit }
// f2$1$1 { $g: () -> Unit }
inline fun f3(g: () -> Unit) = f2 { object { g() } }
// -> f3$$inlined$f2$1 { $g: () -> Unit }
// f3$$inlined$f2$2 { ??? }
// f3$1$1 { $g: () -> Unit }
Should `???` be `this$0: f3$$inlined$f2$1` or `$g: () -> Unit`? This
commit chooses the latter for KT-28064 bytecode and keeps `this$0` when
inlining the old bytecode.
This patch mutes the following test categories:
* Tests with java dependencies (System class,
java stdlib, jvm-oriented annotations etc).
* Coroutines tests.
* Reflection tests.
* Tests with an inheritance from the standard
collections.
The problem was that anonymous classes wasn't regenerated
although they capture another anonymous class that is a subject
for regeneration
#KT-8689 Fixed
