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// RUN: %parallel-boogie "%s" > "%t" | ||
// RUN: %diff "%s.expect" "%t" | ||
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type Value; | ||
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type Tid; | ||
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datatype StampedValue { | ||
StampedValue(ts: int, value: Value) | ||
} | ||
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var {:layer 0,3} mem: [int]StampedValue; | ||
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const n: int; | ||
axiom n >= 1; | ||
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atomic action {:layer 3} scan'() returns (snapshot: [int]StampedValue) | ||
{ | ||
assume (forall j:int :: 1 <= j && j <= n ==> snapshot[j] == mem[j]); | ||
} | ||
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yield procedure {:layer 2} scan() returns (snapshot: [int]StampedValue) | ||
refines scan'; | ||
{ | ||
var i: int; | ||
var b: bool; | ||
var r1: [int]StampedValue; | ||
var r2: [int]StampedValue; | ||
var out: StampedValue; | ||
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while (true) | ||
invariant {:yields} true; | ||
{ | ||
call r1 := scan_f(n); | ||
call r2 := scan_s(n); | ||
assert {:layer 2} (forall j:int :: 1 <= j && j <= n ==> (r1[j] == r2[j] ==> r1[j] == mem[j])); | ||
if (r1 == r2) { | ||
assert {:layer 2} (forall j:int :: 1 <= j && j <= n ==> r1[j] == mem[j]); | ||
snapshot := r1; | ||
break; | ||
} | ||
} | ||
} | ||
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yield right procedure {:layer 2} scan_f(i: int) returns (snapshot: [int]StampedValue) | ||
requires {:layer 2} 0 <= i && i <= n; | ||
ensures {:layer 2} (forall j:int :: 1 <= j && j <= i ==> | ||
snapshot[j]->ts <= mem[j]->ts && | ||
(snapshot[j]->ts == mem[j]->ts ==> snapshot[j]->value == mem[j]->value)); | ||
{ | ||
var out: StampedValue; | ||
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if (i == 0) { | ||
return; | ||
} | ||
par snapshot := scan_f(i-1) | out := read_f(i); | ||
snapshot[i] := out; | ||
} | ||
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yield left procedure {:layer 2} scan_s(i: int) returns (snapshot: [int]StampedValue) | ||
requires {:layer 2} 0 <= i && i <= n; | ||
ensures {:layer 2} (forall j:int :: 1 <= j && j <= i ==> | ||
mem[j]->ts <= snapshot[j]->ts && | ||
(snapshot[j]->ts == mem[j]->ts ==> snapshot[j]->value == mem[j]->value)); | ||
{ | ||
var out: StampedValue; | ||
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if (i == 0) { | ||
return; | ||
} | ||
par snapshot := scan_s(i-1) | out := read_s(i); | ||
snapshot[i] := out; | ||
} | ||
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right action {:layer 2} action_read_f (i: int) returns (out: StampedValue) | ||
{ | ||
var {:pool "K"} k:int; | ||
var {:pool "V"} v:Value; | ||
if (*) { | ||
assume {:add_to_pool "K", mem[i]->ts, k} {:add_to_pool "V", mem[i]->value, v} true; | ||
assume k < mem[i]->ts; | ||
out := StampedValue(k, v); | ||
} else { | ||
out := mem[i]; | ||
} | ||
} | ||
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yield procedure {:layer 1} read_f (i: int) returns (out: StampedValue) | ||
refines action_read_f; | ||
{ | ||
call out := read(i); | ||
} | ||
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left action {:layer 2} action_read_s(i: int) returns (out: StampedValue) | ||
{ | ||
var {:pool "K"} k:int; | ||
var {:pool "V"} v:Value; | ||
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if (*) { | ||
assume {:add_to_pool "K", mem[i]->ts, k} {:add_to_pool "V", mem[i]->value, v} true; | ||
assume k > mem[i]->ts; | ||
out := StampedValue(k, v); | ||
} else { | ||
out := mem[i]; | ||
} | ||
} | ||
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yield procedure {:layer 1} read_s (i: int) returns (out: StampedValue) | ||
refines action_read_s; | ||
{ | ||
call out := read(i); | ||
} | ||
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atomic action {:layer 1,3} action_write (v:Value, i: int) | ||
modifies mem; | ||
{ | ||
var x: StampedValue; | ||
x := mem[i]; | ||
mem[i] := StampedValue(x->ts + 1, v); | ||
} | ||
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action {:layer 1,3} action_read (i: int) returns (v: StampedValue) | ||
{ | ||
v := mem[i]; | ||
} | ||
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yield procedure {:layer 0} read (i: int) returns (v: StampedValue); | ||
refines action_read; |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,2 @@ | ||
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Boogie program verifier finished with 11 verified, 0 errors |