The number of initializations of the `value` field before the live range
begins does not really matter so long as we insert a write of a default
value to the local if there were none.
Don't insert implicit null check on a value of @EnhancedNullability type
used where @EnhancedNullability type is expected.
This uncovers a bunch of other problems in FE and BE.
KT-36343 and KT-36347 are bugs in StrictJavaNullabilityAssertions
implementation which should most likely be fixed in next major language
version (with proper breaking change notice).
KT-36344 is a design problem which should be addressed after 1.4 issues
are resolved.
Similarly to previous commit, this method was unused since its
introduction before 1.0, so we're changing its semantics to throw NPE
and starting to use it with API version >= 1.4.
#KT-22275 In Progress
This method was introduced in c204e8fc67 "just in case" and was never
used. Therefore we're free to change its semantics and use it in all new
generated code (with API version >= 1.4), without even worrying that the
newly used API will leak from inline functions in stdlib when used with
an older API version. Since we agreed to change the type of thrown
exceptions to java.lang.NPE in KT-22275, invoke a new method
throwJavaNpe now which throws that exception instead of KNPE.
Note that the additional method that takes an exception message is still
unused and exists just in case we need to use it in the future. The new
method throwJavaNpe is public also "just in case" we need to invoke it
in the future; currently it's not invoked from the bytecode.
#KT-22275 In Progress
For comparison intrinsics and for instanceof checks, make
it possible to get the the stack value produced and branch
on that directly instead of materializing a boolean to
branch on from it.
That reduces code such as
```
IF_CMPEQ L1
CONST_0
GOTO L2
L1: CONST_1
L2: IFEQ L3
```
to just one IF_CMP instruction.
Introduce lowering to remove null checks for primitive type
expressions and replace them with true/false. Side-effects
are preserved.
Generate ifnull/ifnonnull instructions for null checks instead
of materializing a null literal for an equality check.
All bytecode text tests are run with stdlib in the classpath and only
for JVM backend, therefore directives WITH_RUNTIME, TARGET_BACKEND,
IGNORE_BACKEND are not needed
Most of these tests used this directive as a way to opt in to a new
language feature, and most of those features are already stable for a
long time, so no opt-in is needed. Some other tests used the directive
to opt out from a language feature, replace those by the `LANGUAGE`
directive. One test used the directive to test behavior that actually
depended on the API version; use `API_VERSION` directive there instead.
Kotlinc source’s file DescriptorUtils.kt demonstarted non-deterministic
insertion of checkExpressionValueIsNotNull for value returned by
CallableDescriptor::getOriginal(). It was difficult to reproduce
this behavior on ф smaller example, but I added a test which was
failing once in 5-10 times while I was testing manually.
I believe this bug is close to KT-23704.
This PR addresses non-determinism to a degree when I can run 120
Compilations with './gradlew dist' and get same classes in all
jars in 'dist'.
NOTE that thew fact that insertion of checkExpressionValueIsNotNull may
depend on order of the types seems suspicios. This CL only addresses
non-determinism part, but I believe it’s worth looking into this more
from semantics point of view.
Lateinit local vars are guaranteed to be non-null after store.
So we mark such stores as storing non-null value
(could be useful for some other constructs, too),
and optimize null checks accordingly.
- Turn some const conditions into non-const conditions
- Make sure inlined const values are used where required
(otherwise they are eliminated by POP backward propagation)
KT-16194 Code with unnecessary safe call contains redundant boxing/unboxing for primitive values
KT-12839 Two null checks are generated when manually null checking platform type
Recognize some additional cases of trivial null checks and trivial instance-of checks.
A variable is "checked for null", if it is:
- a function parameter checked with 'INVOKESTATIC kotlin/jvm/internal/Intrinsics.checkParameterIsNotNull'
- checked for nullability with 'IFNULL/IFNONNULL'
- checked for nullability with 'INSTANCEOF'
(if objectref is instance-of T, then objectref is non-null)
Before analyzing nullability, introduce synthetic assumptions for execution branches
where a variable is guaranteed to be null or not null. For example, the following bytecode:
ALOAD 1 // Ljava/lang/String;
IFNULL L
<non-null branch>
L:
<null branch>
is transformed to
ALOAD 1
IFNULL L1
NEW java/lang/String
ASTORE 1 // tells analyzer that variable 1 is non-null
<non-null branch>
L:
<null branch>
L1:
ACONST_NULL
ASTORE 1 // tells analyzer that variable 1 is null
GOTO L
After the analysis is performed on a preprocessed method,
remember the results for "interesting" instructions
and revert the preprocessing transformations.
After that, perform bytecode transformations as usual.
Do not transform INSTANCEOF to-be-reified, because reification at call site
can introduce null checks. E.g.,
inline fun <reified T> isNullable() = null is T
...
assert(isNullable<String?>())
