Previous version of the boxing/unboxing analysis treated merging boxed and non-boxed values as a hazard.
If such merged values are not used (e.g., early return + local variables reused in inlined calls),
corresponding boxing/unboxing operations still can be optimized out.
All information related to boxed value usage by instructions is moved to 'BoxedValueDescriptor'.
Introduce "tainted" (and "clean") boxed values, with the following rules:
merge(B, B) = B, if unboxed types are compatible,
T, otherwise
merge(B, X) = T
merge(T, X) = T
where
X is a non-boxed value,
B is a "clean" boxed value,
T is a "tainted" boxed value.
Postpone decision about value merge hazards until a "tainted" value is used.
Remove redundant NOPs during bytecode optimization.
NOP instruction is required iff one of the following is true:
(a) it is a first bytecode instruction in a try-catch block (JVM BE assumption);
(b) it is a sole bytecode instruction in a source code line (breakpoints on that line will not work).
All other NOP instructions can be removed.
Note that it doesn't really affect the performance for mature JVM implementations.
However, the perceived quality of the generated code is somewhat improved :).
Related: KT-15609
- `invoke` method must always start a suspend functions
- For creation of coroutine that has not been started yet, there are
two special internal interfaces `SuspendFunction0`/`SuspendFunction1`
It fixes VerifyError with coroutines on Dalvik happening because of
variables spilling before/after suspension point
BasicInterpreter from ASM does not distinct 'int' types from other
int-like types like 'byte' or 'boolean', neither do HotSpot and JVM spec.
But it seems like Dalvik does not follow it, and spilling
boolean value into an 'int' field fails with VerifyError on Android 4,
so it's necessary to distinct int types for variables spilling
#KT-13289 Fixed
Do not treat var as alive just because current instruction belongs to an item range
in local variables table, but the item has different sort of type
As liveness analysis is mostly used in coroutines spilling,
not applying this change may lead that to problems on Android (see tests)
POP operations are backward-propagated.
Operation can't be transformed if its result is moved within stack
(by DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, or SWAP).
Unnecessary operations are replaced with NOPs (for debugger).
Unnecessary NOPs are removed.
KT-9922 Suboptimal generation for simple safe call with unused return value
KT-11116 Optimize methods returning Unit
Preserve static initialization semantics for parts by introducing a special "clinit trigger" class.
Insert "static initialization trigger" call to every method of a part class, remove this call on inline.
Always mangle names for private functions in multifile class parts to avoid resolution clashes on inheritance.
NB in codegen tests initializers for all non-const vals are wrapped in 'run { ... }',
so that the initializer is not a constant expression, and some static initialization code should be generated.
