pyos
a9be27e330
Quick quiz:
Q: In a CFG, what does `a -> b -> c -> d` mean?
A: `a`, then `b`, then `c`, then `d`.
Q: In a CFG, what does `a -> b -> d; a -> c -> d` mean?
A: `a`, then `b` or `c`, then `d`.
Q: So how do you encode "a, then (b, then c) or (c, then b), then d`?
A: You can't.
Problem is, you need to, because that's what `a; run2({ b }, { c }); d`
does when `run2` has a contract that it calls both its lambda arguments
in-place: `shuffle(listOf(block1, block2)).forEach { it() }` is a
perfectly valid implementation for it, as little sense as that makes.
So that's what union nodes solve. When a node implements
`UnionNodeMarker`, its inputs are interpreted as "all visited in some
order" instead of the normal "one of the inputs is visited".
Currently this is used for data flow. It *should* also be used for
control flow, but it isn't. But it should be. But that's not so easy.
BTW, `try` exit is NOT a union node; although lambdas in one branch can
be completed according to types' of lambdas in another, data does not
flow between the branches anyway (since we don't know how much of the
`try` executed before jumping into `catch`, and `catch`es are mutually
exclusive) so a `try` expression is more like `when` than a function
call with called-in-place-exactly-once arguments. The fact that
`exitTryExpression` used `processUnionOfArguments` in a weird way
should've hinted at that, but now we know for certain.
96 lines
3.0 KiB
Plaintext
Vendored
96 lines
3.0 KiB
Plaintext
Vendored
digraph smartCastInInit_kt {
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graph [nodesep=3]
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node [shape=box penwidth=2]
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edge [penwidth=2]
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subgraph cluster_0 {
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color=red
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0 [label="Enter class I" style="filled" fillcolor=red];
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1 [label="Exit class I" style="filled" fillcolor=red];
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}
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0 -> {1} [color=green];
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subgraph cluster_1 {
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color=red
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2 [label="Enter function foo" style="filled" fillcolor=red];
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3 [label="Exit function foo" style="filled" fillcolor=red];
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}
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2 -> {3};
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subgraph cluster_2 {
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color=red
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4 [label="Enter class S" style="filled" fillcolor=red];
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5 [label="Exit class S" style="filled" fillcolor=red];
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}
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4 -> {5} [color=green];
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subgraph cluster_3 {
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color=red
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6 [label="Enter function s" style="filled" fillcolor=red];
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subgraph cluster_4 {
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color=blue
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7 [label="Enter block"];
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8 [label="Function call: R|kotlin/TODO|()" style="filled" fillcolor=yellow];
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9 [label="Stub" style="filled" fillcolor=gray];
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10 [label="Jump: ^s R|kotlin/TODO|()" style="filled" fillcolor=gray];
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11 [label="Stub" style="filled" fillcolor=gray];
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12 [label="Exit block" style="filled" fillcolor=gray];
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}
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13 [label="Exit function s" style="filled" fillcolor=red];
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}
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6 -> {7};
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7 -> {8};
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8 -> {13} [label=onUncaughtException];
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8 -> {9} [style=dotted];
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9 -> {10} [style=dotted];
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10 -> {13 11} [style=dotted];
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11 -> {12} [style=dotted];
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12 -> {13} [style=dotted];
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subgraph cluster_5 {
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color=red
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14 [label="Enter function <init>" style="filled" fillcolor=red];
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15 [label="Delegated constructor call: super<R|kotlin/Any|>()" style="filled" fillcolor=yellow];
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16 [label="Exit function <init>" style="filled" fillcolor=red];
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}
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14 -> {15};
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15 -> {16};
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subgraph cluster_6 {
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color=red
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17 [label="Enter init block" style="filled" fillcolor=red];
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subgraph cluster_7 {
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color=blue
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18 [label="Enter block"];
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19 [label="Function call: R|/s|()" style="filled" fillcolor=yellow];
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20 [label="Assignment: R|/Main.x|"];
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21 [label="Access variable R|/Main.x|"];
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22 [label="Smart cast: this@R|/Main|.R|/Main.x|"];
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23 [label="Function call: this@R|/Main|.R|/Main.x|.R|/S.foo|()" style="filled" fillcolor=yellow];
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24 [label="Exit block"];
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}
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25 [label="Exit init block" style="filled" fillcolor=red];
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}
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17 -> {18};
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18 -> {19};
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19 -> {20};
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20 -> {21};
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21 -> {22};
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22 -> {23};
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23 -> {24};
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24 -> {25};
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25 -> {28} [color=green];
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subgraph cluster_8 {
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color=red
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26 [label="Enter class Main" style="filled" fillcolor=red];
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27 [label="Part of class initialization"];
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28 [label="Exit class Main" style="filled" fillcolor=red];
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}
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26 -> {27} [color=green];
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27 -> {28} [style=dotted];
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27 -> {17} [color=green];
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27 -> {17} [style=dashed];
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}
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