Do not generate operations as lambdas; instead use `when` over
strings/enums, which is generated to tableswitch in the bytecode.
This reduces the proguarded compiler jar size by ~0.57%.
#KT-23565 Fixed
This change improves the debugging experience around local functions
on the IR backend. The changes include moving old
checkLocalVariablesTable (cLVT) tests to the new stepping/local variable
infrastructure in order to refine the tests and further define the
behavior of the two JVM backends, and their differences.
The primary ported test case is cLVT/localFun.kt that documents the
discrepancy in implementation strategy for local functions on the two
backends. The old backend implements local functions as lambdas
assigned to a local variable while the IR backend lifts them out as
static funtions on the surrounding class. The discrepancies and their
consequences are documented in bytecodeListing, idea-stepping,
localVariableTable and debugStepping tests.
The only _code change_ is disabling the captured variable name
mangling for captured variables on the IR backend. Captured variables
are passed as arguments to the static function, so in the debugger,
they really just are local variables. For them to show properly in the
debugger and be detectable by evaluate expression, they simply need no
mangling.
Finally, this change cleans 3 redundant cLVT tests, copyFunction.kt
and destructuringInlineLambda.kt and destructuringInFor.kt, that are
all covered in the new suite. The stepping behavior needs to be made
precise around for loops, but that is an entirely seperate issue.
It's not correct to expect that the backend generates the `when` in this
test as tableswitch because there are only two branches. JVM IR has a
cutoff in the when optimization and generates `when`s with fewer than 3
branches as if-else chains, which is probably better. Note that there's
also a corresponding box test in when/enumOptimization/, so the backend
behavior is still tested.
As soon as JVM IR is enabled by default (in language version 1.5), use
the CLI argument `-Xuse-old-backend` or Gradle option `useOldBackend` to
switch to the old JVM backend.
Module 'oracle.desktop' is not guaranteed to be present in JDK. Also,
its usage in these tests doesn't check anything new that isn't already
checked by usages of jdk.net and jdk.httpserver.
This gives us more precise type information and can enable backend
optimizations. This was motivated by when expressions not compiled
to table switches in the JVM_IR backend.
Fixed KT-36845.
Dmitriy Novozhilov