Skip to content

Instantly share code, notes, and snippets.

@loredanacirstea

loredanacirstea/yulToEwasm_div_bug.txt

Created May 17, 2020 13:39
Show Gist options
  • Star 0 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
  • Save loredanacirstea/cf38ace41b609b629293070cbc172216 to your computer and use it in GitHub Desktop.
Save loredanacirstea/cf38ace41b609b629293070cbc172216 to your computer and use it in GitHub Desktop.
Download ZIP
yulToEwasm - div with calldata argument bug
Raw
yulToEwasm_div_bug.txt
solc --version
0.6.8+commit.0bbfe453.Darwin.appleclang
solc --strict-assembly --optimize --yul-dialect evm --machine ewasm ./tests/contracts/taylor.yul
-> const wmodule = new WebAssembly.Module(hexToUint8Array(bytecode));
CompileError: WebAssembly.Module(): Compiling function #9 failed: expected 1 elements on the stack for return, found 0 @+987
======= ./tests/contracts/taylor.yul - initial source =======
object "TestContract" {
code {
datacopy(0, dataoffset("Runtime"), datasize("Runtime"))
return(0, datasize("Runtime"))
}
object "Runtime" {
code {
let _calldata := 256
calldatacopy(_calldata, 0, calldatasize())
mstore(0, div(mload(_calldata), 10))
return (0, 32)
}
}
}
======= ./tests/contracts/taylor.yul (Ewasm) =======
Pretty printed source:
object "TestContract" {
code {
{
let _1 := datasize("Runtime")
datacopy(0, dataoffset("Runtime"), _1)
return(0, _1)
}
}
object "Runtime" {
code {
{
let _1 := 256
calldatacopy(_1, 0, calldatasize())
mstore(0, div(mload(_1), 10))
return(0, 32)
}
}
}
}
==========================
Translated source:
object "TestContract" {
code {
function main()
{
let _1 := datasize("Runtime")
let _2 := 0
let _3:i32 := u256_to_i32(_2, _2, _2, _1)
let _4:i32 := u256_to_i32(_2, _2, _2, dataoffset("Runtime"))
let p:i32 := u256_to_i32(_2, _2, _2, _2)
let r:i32 := i32.add(p, 64:i32)
if i32.lt_u(r, p) { unreachable() }
eth.codeCopy(r, _4, _3)
let _5:i32 := u256_to_i32(_2, _2, _2, _1)
let p_1:i32 := u256_to_i32(_2, _2, _2, _2)
let r_1:i32 := i32.add(p_1, 64:i32)
if i32.lt_u(r_1, p_1) { unreachable() }
eth.finish(r_1, _5)
}
function u256_to_i32(x1, x2, x3, x4) -> v:i32
{
if i64.ne(0, i64.or(i64.or(x1, x2), x3)) { unreachable() }
if i64.ne(0, i64.shr_u(x4, 32)) { unreachable() }
v := i32.wrap_i64(x4)
}
}
object "Runtime" {
code {
function main()
{
let _1 := i64.extend_i32_u(eth.getCallDataSize())
let _2 := 0
let _3:i32 := u256_to_i32(_2, _2, _2, _1)
let _4:i32 := u256_to_i32(_2, _2, _2, _2)
let _5 := 256
let p:i32 := u256_to_i32(_2, _2, _2, _5)
let r:i32 := i32.add(p, 64:i32)
if i32.lt_u(r, p) { unreachable() }
eth.callDataCopy(r, _4, _3)
let p_1:i32 := u256_to_i32(_2, _2, _2, _5)
let r_1:i32 := i32.add(p_1, 64:i32)
if i32.lt_u(r_1, p_1) { unreachable() }
let z1 := endian_swap(i64.load(r_1))
let z2 := endian_swap(i64.load(i32.add(r_1, 8:i32)))
let z3 := endian_swap(i64.load(i32.add(r_1, 16:i32)))
let _6, _7, _8, _9 := div(z1, z2, z3, endian_swap(i64.load(i32.add(r_1, 24:i32))), _2, _2, _2, 10)
let _10:i32 := to_internal_i32ptr(_2, _2, _2, _2)
i64.store(_10, endian_swap(_6))
i64.store(i32.add(_10, 8:i32), endian_swap(_7))
i64.store(i32.add(_10, 16:i32), endian_swap(_8))
i64.store(i32.add(_10, 24:i32), endian_swap(_9))
return(_2, _2, _2, _2, _2, _2, _2, 32)
}
function add_carry(x, y, c) -> r, r_c
{
let t := i64.add(x, y)
r := i64.add(t, c)
r_c := i64.extend_i32_u(i32.or(i64.lt_u(t, x), i64.lt_u(r, t)))
}
function add(x1, x2, x3, x4, y1, y2, y3, y4) -> r1, r2, r3, r4
{
let t := i64.add(x4, y4)
r4 := i64.add(t, 0)
let r3_1, carry := add_carry(x3, y3, i64.extend_i32_u(i32.or(i64.lt_u(t, x4), i64.lt_u(r4, t))))
r3 := r3_1
let r2_1, carry_1 := add_carry(x2, y2, carry)
r2 := r2_1
let r1_1, carry_2 := add_carry(x1, y1, carry_1)
r1 := r1_1
}
function sub(x1, x2, x3, x4, y1, y2, y3, y4) -> r1, r2, r3, r4
{
let _1 := 0xffffffffffffffff
let t := i64.add(x4, i64.xor(y4, _1))
r4 := i64.add(t, 1)
let r3_1, carry := add_carry(x3, i64.xor(y3, _1), i64.extend_i32_u(i32.or(i64.lt_u(t, x4), i64.lt_u(r4, t))))
r3 := r3_1
let r2_1, carry_1 := add_carry(x2, i64.xor(y2, _1), carry)
r2 := r2_1
let r1_1, carry_2 := add_carry(x1, i64.xor(y1, _1), carry_1)
r1 := r1_1
}
function shl_internal(amount, x1, x2, x3, x4) -> r1, r2, r3, r4
{
let _1 := i64.sub(64, amount)
r1 := i64.add(i64.shl(x1, amount), i64.shr_u(x2, _1))
r2 := i64.add(i64.shl(x2, amount), i64.shr_u(x3, _1))
r3 := i64.add(i64.shl(x3, amount), i64.shr_u(x4, _1))
r4 := i64.shl(x4, amount)
}
function shr_internal(amount, x1, x2, x3, x4) -> r1, r2, r3, r4
{
let _1 := i64.sub(64, amount)
r4 := i64.add(i64.shr_u(x4, amount), i64.shl(x3, _1))
r3 := i64.add(i64.shr_u(x3, amount), i64.shl(x2, _1))
r2 := i64.add(i64.shr_u(x2, amount), i64.shl(x1, _1))
r1 := i64.shr_u(x1, amount)
}
function div(x1, x2, x3, x4, y1, y2, y3, y4) -> r1, r2, r3, r4
{
if i64.eqz(i64.or(i64.or(y1, y2), i64.or(y3, y4))) { leave }
let m1 := 0
let m2 := m1
let m3 := m1
let m4 := 1
for { } true { }
{
if i32.or(i64.eqz(i64.clz(y1)), i32.eqz(lt_256x256_64(y1, y2, y3, y4, x1, x2, x3, x4))) { break }
let y1_1, y2_1, y3_1, y4_1 := shl_internal(1, y1, y2, y3, y4)
y1 := y1_1
y2 := y2_1
y3 := y3_1
y4 := y4_1
let m1_1, m2_1, m3_1, m4_1 := shl_internal(1, m1, m2, m3, m4)
m1 := m1_1
m2 := m2_1
m3 := m3_1
m4 := m4_1
}
for { }
i32.eqz(i64.eqz(i64.or(i64.or(m1, m2), i64.or(m3, m4))))
{ }
{
if i32.eqz(lt_256x256_64(x1, x2, x3, x4, y1, y2, y3, y4))
{
let x1_1, x2_1, x3_1, x4_1 := sub(x1, x2, x3, x4, y1, y2, y3, y4)
x1 := x1_1
x2 := x2_1
x3 := x3_1
x4 := x4_1
let r1_1, r2_1, r3_1, r4_1 := add(r1, r2, r3, r4, m1, m2, m3, m4)
r1 := r1_1
r2 := r2_1
r3 := r3_1
r4 := r4_1
}
let y1_2, y2_2, y3_2, y4_2 := shr_internal(1, y1, y2, y3, y4)
y1 := y1_2
y2 := y2_2
y3 := y3_2
y4 := y4_2
let m1_2, m2_2, m3_2, m4_2 := shr_internal(1, m1, m2, m3, m4)
m1 := m1_2
m2 := m2_2
m3 := m3_2
m4 := m4_2
}
}
function cmp(a, b) -> r:i32
{
switch i64.lt_u(a, b)
case 1:i32 { r := 0xffffffff:i32 }
default { r := i64.ne(a, b) }
}
function lt_256x256_64(x1, x2, x3, x4, y1, y2, y3, y4) -> z:i32
{
switch cmp(x1, y1)
case 0:i32 {
switch cmp(x2, y2)
case 0:i32 {
switch cmp(x3, y3)
case 0:i32 { z := i64.lt_u(x4, y4) }
case 1:i32 { z := 0:i32 }
default { z := 1:i32 }
}
case 1:i32 { z := 0:i32 }
default { z := 1:i32 }
}
case 1:i32 { z := 0:i32 }
default { z := 1:i32 }
}
function u256_to_i32(x1, x2, x3, x4) -> v:i32
{
if i64.ne(0, i64.or(i64.or(x1, x2), x3)) { unreachable() }
if i64.ne(0, i64.shr_u(x4, 32)) { unreachable() }
v := i32.wrap_i64(x4)
}
function to_internal_i32ptr(x1, x2, x3, x4) -> r:i32
{
let p:i32 := u256_to_i32(x1, x2, x3, x4)
r := i32.add(p, 64:i32)
if i32.lt_u(r, p) { unreachable() }
}
function endian_swap_16(x) -> y
{
y := i64.or(i64.and(i64.shl(x, 8), 0xff00), i64.and(i64.shr_u(x, 8), 0xff))
}
function endian_swap_32(x) -> y
{
let hi := i64.shl(endian_swap_16(x), 16)
y := i64.or(hi, endian_swap_16(i64.shr_u(x, 16)))
}
function endian_swap(x) -> y
{
let hi := i64.shl(endian_swap_32(x), 32)
y := i64.or(hi, endian_swap_32(i64.shr_u(x, 32)))
}
function return(x1, x2, x3, x4, y1, y2, y3, y4)
{
eth.finish(to_internal_i32ptr(x1, x2, x3, x4), u256_to_i32(y1, y2, y3, y4))
}
}
}
}
Binary representation:
0061736d0100000001170460000060047e7e7e7e017e60027f7f0060037f7f7f0002270208657468657265756d08636f6465436f7079000308657468657265756d0666696e697368000203030200010503010001060100071102066d656d6f72790200046d61696e000200810e0752756e74696d650061736d01000000014d0b6000006000017f60017e017e60027e7e017e60037e7e7e017e60047e7e7e7e017e60057e7e7e7e7e017e60087e7e7e7e7e7e7e7e0060087e7e7e7e7e7e7e7e017e60027f7f0060037f7f7f0002460308657468657265756d0f67657443616c6c4461746153697a65000108657468657265756d0666696e697368000908657468657265756d0c63616c6c44617461436f7079000a03100f00040808060608030805050202020705030100010610037e0142000b7e0142000b7e0142000b071102066d656d6f72790200046d61696e00030a9b0c0fb40201117e1000ada7ad2100420021012001200120012000100c21022001200120012001100c210342800221042001200120012004100c21052005a742c000a76aad21062006a72005a749ad4200520440000b2006a72003a72002a710022001200120012004100c21072007a742c000a76aad21082008a72007a749ad4200520440000b2008a7290300101021092008a74208a76aada72903001010210a2008a74210a76aada72903001010210b02402009200a200b2008a74218a76aada72903001010200120012001420a1009210c2300210d2301210e2302210f0b2001200120012001100d21102010a7200c10103703002010a74208a76aada7200d10103703002010a74210a76aada7200e10103703002010a74218a76aada7200f10103703002001200120012001200120012001422010110b2c01037e200020017c2105200520027c21032005200054ada72003200554ada772ada7ad21042004240020030b6f010b7e200320077c210c200c42007c210b024020022006200c200354ada7200b200c54ada772ada7ad1004210d2300210e0b200d210a024020012005200e1004210f230021100b200f2109024020002004201010042111230021120b2011210820092400200a2401200b240220080b7f010c7e427f210c20032007200c857c210d200d42017c210b024020022006200c85200d200354ada7200b200d54ada772ada7ad1004210e2300210f0b200e210a024020012005200c85200f10042110230021110b20102109024020002004200c85201110042112230021130b2012210820092400200a2401200b240220080b4801057e42c00020007d2109200120008620022009887c2105200220008620032009887c2106200320008620042009887c21072004200086210820062400200724012008240220050b4801057e42c00020007d2109200420008820032009867c2108200320008820022009867c2107200220008820012009867c21062001200088210520062400200724012008240220050bbb0301207e200420058420062007848450ad42005204400f0b4200210c200c210d200c210e4201210f024003404201500d01024020047950ada720042005200620072000200120022003100ba745ada772ad42005204400c030b024042012004200520062007100721102300211123012112230221130b2010210420112105201221062013210702404201200c200d200e200f100721142300211523012116230221170b2014210c2015210d2016210e2017210f0b0b0b02400340200c200d84200e200f848450ada745ad500d01024020002001200220032004200520062007100ba745ad420052044002402000200120022003200420052006200710062118230021192301211a2302211b0b2018210020192101201a2102201b2103024020082009200a200b200c200d200e200f1005211c2300211d2301211e2302211f0b201c2108201d2109201e210a201f210b0b024042012004200520062007100821202300212123012122230221230b2020210420212105202221062023210702404201200c200d200e200f100821242300212523012126230221270b2024210c2025210d2026210e2027210f0b0b0b20092400200a2401200b240220080b2a01027e02402000200154ad21032003420151044042ffffffff0f2102052000200152ad21020b0b20020b7d01047e024020002004100a210920094200510440024020012005100a210a200a4200510440024020022006100a210b200b42005104402003200754ad210805200b42015104404200210805420121080b0b0b05200a42015104404200210805420121080b0b0b05200942015104404200210805420121080b0b0b20080b2f01017e4200200020018420028452ad4200520440000b4200200342208852ad4200520440000b2003a7ad210420040b2c01027e2000200120022003100c21052005a742c000a76aad21042004a72005a749ad4200520440000b20040b1c01017e20004208864280fe0383200042088842ff018384210120010b1b01027e2000100e421086210220022000421088100e84210120010b1b01027e2000100f422086210220022000422088100f84210120010b1c01007e2000200120022003100da72004200520062007100ca710010b0ac40102910101097e42f90d21004200210120012001200120001003210220012001200142f500100321032001200120012001100321042004a742c000a76aad21052005a72004a749ad4200520440000b2005a72003a72002a710002001200120012000100321062001200120012001100321072007a742c000a76aad21082008a72007a749ad4200520440000b2008a72006a710010b2f01017e4200200020018420028452ad4200520440000b4200200342208852ad4200520440000b2003a7ad210420040b
Text representation:
(module
;; sub-module "Runtime" will be encoded as custom section in binary here, but is skipped in text mode.
(import "ethereum" "codeCopy" (func $eth.codeCopy (param i32 i32 i32)))
(import "ethereum" "finish" (func $eth.finish (param i32 i32)))
(memory $memory (export "memory") 1)
(export "main" (func $main))
(func $main
(local $_1 i64)
(local $_2 i64)
(local $_3 i64)
(local $_4 i64)
(local $p i64)
(local $r i64)
(local $_5 i64)
(local $p_1 i64)
(local $r_1 i64)
(local.set $_1 (datasize "Runtime"))
(local.set $_2 (i64.const 0))
(local.set $_3 (call $u256_to_i32 (local.get $_2) (local.get $_2) (local.get $_2) (local.get $_1)))
(local.set $_4 (call $u256_to_i32 (local.get $_2) (local.get $_2) (local.get $_2) (dataoffset "Runtime")))
(local.set $p (call $u256_to_i32 (local.get $_2) (local.get $_2) (local.get $_2) (local.get $_2)))
(local.set $r (i64.extend_i32_u (i32.add (i32.wrap_i64 (local.get $p)) (i32.wrap_i64 (i64.const 64)))))
(if (i64.ne (i64.extend_i32_u (i32.lt_u (i32.wrap_i64 (local.get $r)) (i32.wrap_i64 (local.get $p)))) (i64.const 0)) (then
(unreachable)))
(call $eth.codeCopy (i32.wrap_i64 (local.get $r)) (i32.wrap_i64 (local.get $_4)) (i32.wrap_i64 (local.get $_3)))
(local.set $_5 (call $u256_to_i32 (local.get $_2) (local.get $_2) (local.get $_2) (local.get $_1)))
(local.set $p_1 (call $u256_to_i32 (local.get $_2) (local.get $_2) (local.get $_2) (local.get $_2)))
(local.set $r_1 (i64.extend_i32_u (i32.add (i32.wrap_i64 (local.get $p_1)) (i32.wrap_i64 (i64.const 64)))))
(if (i64.ne (i64.extend_i32_u (i32.lt_u (i32.wrap_i64 (local.get $r_1)) (i32.wrap_i64 (local.get $p_1)))) (i64.const 0)) (then
(unreachable)))
(call $eth.finish (i32.wrap_i64 (local.get $r_1)) (i32.wrap_i64 (local.get $_5)))
)
(func $u256_to_i32
(param $x1 i64)
(param $x2 i64)
(param $x3 i64)
(param $x4 i64)
(result i64)
(local $v i64)
(if (i64.ne (i64.extend_i32_u (i64.ne (i64.const 0) (i64.or (i64.or (local.get $x1) (local.get $x2)) (local.get $x3)))) (i64.const 0)) (then
(unreachable)))
(if (i64.ne (i64.extend_i32_u (i64.ne (i64.const 0) (i64.shr_u (local.get $x4) (i64.const 32)))) (i64.const 0)) (then
(unreachable)))
(local.set $v (i64.extend_i32_u (i32.wrap_i64 (local.get $x4))))
(local.get $v)
)
)
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment