If `mapLineNumber` was called in non-monotonic order, e.g. N then N+2
then N+1, the first two calls created a range that spans [N; N+2] but
the third call did not reuse it.
* 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()
```
This PR enables LineNumberTestGenerated test on IR backend. The testing of
hardcoded sequence of line numbers is replaced with mere checks for set-like
checks for expected line numbers.
Dex ignores subsequent line numbers for same instructions and interprets
instruction after inline as if they were inlined. This makes debugger
behaves as if there's nowhere to stop on line with breakpoint.
This also makes stepping through inline function consistent with
non-inline analog. In both context debugger now stops on '}'.
#KT-18949 Fixed
#KT-17120 Fixed
Before this fix line numbers for function call arguments were not generated,
so if argument was on another line than function call it was
impossible to stop on argument line during debugging.
Now line number for each argument is generated if necessary
(another line than function call line).
#KT-17144 Fixed
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
Revert changes for "tolerant to uninitialized values" in OptimizationBasicInterpreter:
this approach doesn't converge for some specific cases where local variable is reused
(e.g., in several inlined functions - see https://youtrack.jetbrains.com/issue/KT-15112).
Instead, treat fake always-false conditional jump in the beginning of the post-condition loop as a "reference point" for stack on loop break / continue.
This requires an extra abstraction layer in FixStackAnalyzer, since we can't perform fine-grain manipulations on Frames
(such as "combine frame C from local variables of frame A and stack of frame B").
NB additional NOPs will be generated for post-condition loops.
Should make a separate bytecode postprocessing pass to get rid of unnecessary NOPs
(several YT issues for perceived quality of the generated bytecode are about such NOPs).
Otherwise linenumber for previous instruction will be used in debugger. That can lead to error stepping
because it might be line that isn't reachable on current iteration.
#KT-13059 Fixed
Comma must present now between enum entries, semicolon between last entry & first member, constructor calls must be without colons / specifiers.
A swarm of tests fixed accordingly.
pyos