Codegen generates static backing fields for object properties.
They are initialized in class constructor but some of them are final static
and such access is prohibited in specification but it's allowed in
java bytecode <= 1.8. Such access in 1.9 bytecode cause
"IllegalAccessError: Update to static final field Object.INSTANCE
attempted from a different method (<init>) than the initializer method <clinit>"
Added additional hidden field in interface companion to pass out
companion instance from <clinit>.
#KT-15894 Fixed
Three modes:
- 'disable' (default): normalize constructor calls in coroutines only
(required because uninitialized objects can't be stored in fields),
don't insert additional code for forced class initialization;
- 'enable': normalize constructor calls,
don't insert additional code for forced class initialization;
- 'preserve-class-initialization': normalize constructor calls,
insert additional code for forced class initialization.
Stack should be spilled before inline function call and restored after
call only if one of the following conditions is met:
- inline function is a suspend function
- inline function has try-catch blocks
- inline function has loops (backward jumps)
Note that there're quite some "simple" inline functions in Kotlin stdlib
besides run/let/with/apply. For example, many string operations are
implemented as inline wrappers over Java method calls.
Singleton instance is "initialized" by delegating constructor call,
which is superclass constructor call in case of singletons (because
singletons can't have more than one constructor).
Singleton constructor is effectively split into two stages:
- before a super constructor call;
- after a super constructor call.
Before super constructor call, singleton instance can't be used directly
(see KT-20662), because neither 'this' nor static instance is
initialized yet. However, it can be used in closures, in which case a
static instance should be used (escaping uninitialized this is
prohibited by JVM). Actually using this static instance before it is
initialized (e.g., invoking a method that uses this singleton) will
cause a correct ExceptionInInitializerError.
After a super constructor call, static instance of a singleton may be
not initialized yet (in case of enum entries and interface companion
objects). However, we already have an initialized 'this', which we
should use for singleton references.
#KT-20651 Fixed
Jump out from expression (e.g., break or continue expression in call
arguments) requires stack normalization, which inserts POP instructions.
POPping an uninitialized value is similar to ASTORE, except that it
doesn't store a value to a local variable. Such POP instructions should
be removed during postprocessing of the uninitialized stores.
Do it in the same way as Java: prohibit inner classes (including
anonymous inner classes) capturing type parameters from outer classes
(but not outer methods) extending Throwable.
See KT-17981:
- Deprecated in 1.2
- Error in 1.3
It's anyway is obvious for write instruction, while effectively
after optimizations we treat val with syntactic initializer
uninitialized until their immediate initiazer
Parameters/vals with an immediate initializer (which we assume is a
rather common situation) do not require any kind of complicated CFA
- Unused vals can be simply determined by linear traversal of
the pseudocode
- Definite assignment is a bit more complicated: a read-instruction of val
can be considered as a safe if it's located *after* the first write in
the pseudocode. It works almost always beside the case with do/while
(see the test changed). This case will be fixed in the further commits
The test for kt897.kt will also be fixed further, all other changes
might be considered as minor as they mostly change diagnostics for
already red code
Alexander Udalov