* In blocks, discard the result of any statement that has a return
type other than void. This was previously done by wrapping each
statement into an "implicit Unit conversion" that was actually
compiled down to a stack pop instead. If an expression happened to
already have type Unit, however, such a conversion was not inserted,
resulting in a stray reference on the stack. These conversions are
now redundant and should probably be removed.
* In assignments and non-exhaustive conditionals, materialize a Unit
on the stack to avoid depth mismatches that trip up the bytecode
validator. Because such expressions are generally used at block level
(and, indeed, the frontend will reject a non-exhaustive conditional
used as an expression), combined with the above change this results
in no additional GETSTATIC opcodes, as they are immediately removed
by the peephole optimizer.
In TopDownAnalyzerFacadeForJVM, we now always use the "load built-ins
from module dependencies" behavior that was previously only enabled with
the dedicated CLI argument -Xload-builtins-from-dependencies. However,
sometimes we compile code without kotlin-stdlib in the classpath, and we
don't want everything to crash because some standard type like
kotlin.Unit hasn't been found.
To mitigate this, we add another module at the end of the dependencies
list, namely a "fallback built-ins" module. This module loads all
built-in declarations from the compiler's class loader, as was done by
default previously. This prevents the compiler from crashing if any
built-in declaration is not found, but compiling the code against
built-ins found in the compiler is still discouraged, so we report an
error if anything is resolved to a declaration from this module, via a
new checker MissingBuiltInDeclarationChecker.
Also introduce a new CLI argument -Xsuppress-missing-builtins-error
specifically to suppress this error and to allow compiling code against
compiler's own built-ins.
#KT-19227 Fixed
#KT-28198 Fixed
Effectively, the following when structure:
when (s) {
s1, s2 -> e1,
s3 -> e2,
s4 -> e3,
...
else -> e
}
is implemented as:
when (s.hashCode()) {
h1 -> {
if (s == s1)
e1
else if (s == s2)
e1
else if (s == s3)
e2
else
e
}
h2 -> if (s == s3) e2 else e,
...
else -> e
}
where s1.hashCode() == s2.hashCode() == s3.hashCode() == h1,
s4.hashCode() == h2.
A tableswitch or lookupswitch is used for the hash code lookup.
Change-Id: I087bf623dbb4a41d3cc64399a1b42342a50757a6
Inner class constructors should use the argument instead of reading
outer `this` from a field because if such an access happens before a
delegating constructor call, e.g. when evaluating an argument, a JVM
bytecode validation error will be thrown. (The only operation on `this`
allowed before a delegating constructor call is SETFIELD, and only if
the field in question is declared in the same class.)
Specifically, defer the removal of hand-written "if (true|false)" from
JvmBuiltinOptimizationLowering into codegen so that appropriate debug
info (and a NOP) can be inserted.
Change-Id: Ia11af05ad8b4251946bd3e685fb7c3319f0f433f
This however makes testLocalFunctionName fail because currently
isSubclassOf (incorrectly) returns false and therefore an anonymous
class is generated and the name is taken from there. The name there is
"box$OK" which is incorrect. The isSubclassOf issue is KT-28198 and will
be fixed separately; the incorrect name issue will be investigated later
Follow-up of 9b3e17f0. There we decided to complete call if a type
variable from a return type has proper lower constraints, now we refine
this rule wrt `Nothing`-like constraints to avoid inferring type variables
to Nothing, which is quite useless
#KT-30370 Fixed
A lookupswitch or tableswitch can be used if all conditions are equality
checks to constants. To be more specific, it can be done if:
1. All conditions are CALL 'EQEQ(Any?, Any?)': Boolean
2. All types of variables involved in comparison are in the same group
of Char/Byte/Short/Int, String or enum.
3. All arg0 refer to the same value.
4. All arg1 are IrConst<*>.
Change-Id: Ifd7cb618395f6c5cc64601018b446f0bb7f5891c
Dmitriy Novozhilov