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Upstream symbolic bytes lookup, List membership lemmas #2702

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Upstream symbolic bytes lookup, List membership lemmas #2702

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4cc162b
Add bytes lookup lemmas
palinatolmach Feb 6, 2025
f8fc873
Merge branch 'master' into add-bytes-lookup-lemmas
palinatolmach Mar 13, 2025
bb13a1e
Merge branch 'master' into add-bytes-lookup-lemmas
palinatolmach Jul 29, 2025
ba11591
Add test for the symbolic bytes index lookup lemma
palinatolmach Jul 29, 2025
73be258
Add List membership lemmas
palinatolmach Jul 29, 2025
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16 changes: 16 additions & 0 deletions kevm-pyk/src/kevm_pyk/kproj/evm-semantics/lemmas/bytes-simplification.k
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Expand Up @@ -285,4 +285,20 @@ module BYTES-SIMPLIFICATION [symbolic]
rule #asWord ( #ecrec ( _ , _ , _ , _ ) ) <Int pow160 => true
[simplification, smt-lemma]

// Symbolic bytes lookup

rule [bytes-concat-lookup-left]:
( B1:Bytes +Bytes B2:Bytes ) [ I:Int ] => B1 [ I ]
requires 0 <=Int I andBool I <Int lengthBytes(B1)
[simplification(40), preserves-definedness]

rule [bytes-concat-lookup-right]:
( B1:Bytes +Bytes B2:Bytes ) [ I:Int ] => B2 [ I -Int lengthBytes(B1) ]
requires lengthBytes(B1) <=Int I
[simplification(40), preserves-definedness]

rule [lookup-as-asWord]:
B:Bytes [ I:Int ] => #asWord ( #range ( B, I, 1 ) )
requires 0 <=Int I andBool I <=Int lengthBytes(B)
[simplification(60)]
endmodule
13 changes: 13 additions & 0 deletions kevm-pyk/src/kevm_pyk/kproj/evm-semantics/lemmas/lemmas.k
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Expand Up @@ -132,6 +132,19 @@ module LEMMAS-WITHOUT-SLOT-UPDATES [symbolic]
// Hardcoded #addrFromPrivateKey simplifications, see: https://github.com/runtimeverification/haskell-backend/issues/3573
rule #addrFromPrivateKey("0x0000000000000000000000000000000000000000000000000000000000000001") => 721457446580647751014191829380889690493307935711 [priority(40), concrete]

// ########################
// List Reasoning
// ########################

// List membership check simplification for lists with a single element
rule KI:KItem in ListItem(KI:KItem) => true [simplification]
rule KI:KItem in ListItem(KJ:KItem) => KI ==K KJ [simplification]

// Recursive list membership check for lists with multiple elements
rule KI:KItem in (ListItem(KI) _REST) => true [simplification]
rule KI:KItem in (ListItem(KJ) REST) => KI in REST requires KI =/=K KJ [simplification]
rule _KI:KItem in .List => false [simplification]

// ########################
// Memory
// ########################
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13 changes: 13 additions & 0 deletions tests/specs/functional/lemmas-spec.k
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Expand Up @@ -148,6 +148,12 @@ module LEMMAS-SPEC
</k>
requires X =/=K Y

// List simplifications
// --------------------

claim [list-in-simplification]:
<k> runLemma ( b"\xd3V\x97\x17" in ListItem ( b"Y\xecK\x01" +Bytes #buf ( 32 , W:Int ) ) ) => doneLemma ( false ) ... </k>
requires #rangeUInt(256, W)

// Memory update simplifications
// ----------------------------
Expand Down Expand Up @@ -366,6 +372,13 @@ module LEMMAS-SPEC
=> doneLemma(true) ... </k>
requires lengthBytes ( BYTES:Bytes ) <Int 32

// Symbolic bytes lookup simplification
// -------------------
claim [lookup-symbolic-bytes]:
<k> runLemma ( b"`\xa0`@R4\x80\x15a\x00\x10W`\x00" +Bytes #buf ( 32 , W:Int ) [ 0 ] )
=> doneLemma ( 96 ) ... </k>
requires #rangeUInt(256, W)

// #buf simplification
// -------------------
claim [bufExtractPadding]: <k> runLemma ( #asWord ( ( #range( #buf ( 32 , X ), 0, 28 ) ):Bytes ) ) => doneLemma ( 0 ) ... </k> requires #rangeUInt(32, X)
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