This commit fixes two issues in the existing implementation of translating primitive array types:
* IrType.getArrayElementType throws an exception when the receiver is a primitive array type, because IR expects primitive array types use symbols defined in IrBuiltIns, but fir2ir translation doesn't;
* IteratorNext.toCallable assumes all element types are boxed.
The first issue is fixed by changing the fir2ir type translation to use symbols in IrBuiltIns for primitive array types, and the second by not unboxing primitive types.
* 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.
Simplify ifs when branches have condition true/false.
Simplify blocks containing only a variable declaration
and a variable get of the same variable. Simplify to
just the condition.
Do not introduce temporary variables for constants for
null checks. Constants have no side-effects and can be
reloaded freely instead of going through a local.
This simplifies code such as "42.toLong()!!" so that the
resulting code has no branches and uses no locals. The
simplifications happen as follows:
```
block
temp = 42.toLong()
when
(temp == null) throw NPE
(true) load temp
---> null test simplification
block
temp = 42.toLong()
when
(false) throw NPE
(true) load temp
---> when simplification
block
temp = 42.toLong()
load temp
---> block simplification
42.toLong()
```
FixStack transformation divides on phases:
- Fixing stack before break/continue
- Fixing stack for inline markers/try-catch blocks
After the first stage all ALWAYS_TRUE markers are replaced
with simple GOTO's and if we're skipping break/continue edges
we won't reach the code after while (true) statement.
At the same time it's fine to not to skip them in the second phase
as the stack for them is already corrected in the first phase
#KT-19475 Fixed
It never terminates, so the corresponding value on stack can't be used.
However, if this happens in an inlined lambda argument, the inliner is
unable to remove the corresponding ALOAD instruction (because default
handler never terminates, and thus corresponding ALOAD is not used for
lambda invocation).
KT-17573 try-finally expression in inlined function parameter argument fails with VerifyError
When a try-catch expression is passed as an argument to the inline
lambda parameter, lambda variable on stack is spilled and restored in
several different locations (1 for try-block, 1 for each catch-blocks).
So it's possible that lambda to be invoked comes from multiple loads,
all of which should have the same "root" lambda parameter.
Parse TryCatchBlockNode's in generated bytecode, infer stack save/restore points.
Save stack to local variables before 'try'.
Restore stack after the beginning of try-block, catch-block, and default handler.
Integrate before/after inline markers rewriting (otherwise it'll break our stacks).
#KT-3309 Fixed
