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$0` when
inlining the old bytecode.
We should only insert a return statement at the end of a lambda or
function if the final statement is used as an expression (slice
USED_AS_RESULT_OF_LAMBDA and USED_AS_EXPRESSION).
NOTE: jvmCrossinlineLambdaDeclarationSite.kt is muted because the
inliner does not remap references to an anonymous object's parent
class after regenerating it. Unlike the JVM backend, JVM_IR uses the
top level named class' assertion status for all inner classes. (The
test used to pass because the lambda in `inline fun call` read the
`$assertionsDisabled` field of `CrossinlineLambdaContainer`, which
was not reloaded after changing the assertion status of package `test`.)
This fixes the problem where compiling a class initializer that contains
a call to an `assert`ing function in a separate module causes the
assertion to always be enabled (i.e. the attached test used to fail in
CompileKotlinAgainstInlineKotlin mode).
and fake lambda types, too. (But those only matter for debugging.)
Also, share object name generators between methods with the same name to
avoid rewriting objects from one with objects from the other.
Any access to a function from a multi-file part needs to be replaced
with the access to the corresponding public method (if it exists) from
the facade class. Note that this has no immediate effect because we use
KotlinTypeMapper for mapping calls, and it understands that a call to a
function from the part must actually be generated into a call to the
function from the facade in the bytecode. This commit merely changes the
IR to better reflect what's generated in the final bytecode, and to be
able to use simplified IR-based method signature mapping instead of the
legacy KotlinTypeMapper in the future.
Note: this currently results in invalid IR (but valid bytecode) if the
@JvmStatic function is imported, because its IR representation is
unlowered and therefore has a dispatch receiver, but the call will not.
Previously it was linear scan, failing on unbalanced suspension markers.
Now, I use CFG to find end markers, which are reachable from start
markers. Using CFG allows to walk through suspension point instructions
only, since they form region.
If, for some reason, end marker does not exist (inliner or unreachable
code elimination pass remove unreachable code) or is unreachable,
just ignore the whole suspension point, as before.
#KT-33172 Fixed
#KT-28507 Fixed
Without the `-Xmultifile-parts-inherit` mode for now.
This is implemented as follows: FileClassLowering collects information
about multifile parts and the corresponding facades, which a later
GenerateMultifileFacades phase uses to generate new IrFile instances and
add it to the module fragment that's being compiled.
Note that GenerateMultifileFacades is in the end of lowering phases
because delegates in the facade should be generated for all additional
functions generated by certain lowerings (default arguments,
JvmOverloads, etc.). If GenerateMultifileFacades was right after
FileClassLowering, they would still be generated, but we'd then process
them in lowerings mentioned above, which would result in duplicated
logic in the bytecode. There's a new bytecode text test which checks
that this doesn't happen for functions with default arguments.
Unlike previously, this optimisation works on every callee return type.
Tail-calls inside unit functions can be either
INVOKE...
ARETURN
or
INVOKE
POP
GETSTATIC kotlin/Unit.INSTANCE
ARETURN
The first pattern is already covered. The second one is a bit tricky,
since we cannot just assume than the function is tail-call, we also need
to check whether the callee returned COROUTINE_SUSPENDED marker.
Thus, resulting bytecode of function's 'epilogue' look like
DUP
INVOKESTATIC getCOROUTINE_SUSPENDED
IF_ACMPNE LN
ARETURN
LN:
POP
#KT-28938 Fixed
re-ordering the lowering phases.
The changes in InterfaceLowering are necessary so that IrElements that
target the removed functions are re-targeted to the new functions in
DefaultImpls. This affects local functions in interface functions since
now LocalDeclarationsLowering comes before InterfaceLowering.
pyos