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Rewrite the runtime bytecode and not just the constructor bytecode #17

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Rewrite the runtime bytecode and not just the constructor bytecode #17

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1e3f9b3
fix
shellygr Mar 12, 2021
42deef7
newline
shellygr Mar 12, 2021
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37 changes: 37 additions & 0 deletions libsolidity/interface/CompilerStack.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1179,6 +1179,35 @@ std::vector<std::size_t> findMatches(const bytes haystack,
return indexes;
}

// Replaces kall which does not get screwed by optimizer with kall we actually want.
void rewriteOptimizerDodgingCode(evmasm::LinkerObject& codeObject)
{
// the bytes that `kall` is assigned via EVMDialect.cpp
bytes kallPlaceholder{
0x33, 0x60, 0x00, 0x90, 0x5a, 0xf1, 0x58, 0x60, 0x1d, 0x01, 0x57, 0x3d, 0x60, 0x01, 0x14, 0x58, 0x60, 0x0c, 0x01, 0x57, 0x3d, 0x60, 0x00, 0x80, 0x3e, 0x3d, 0x62, 0x12, 0x34, 0x56, 0x52, 0x60, 0xea, 0x61, 0x10, 0x9c, 0x52
};

// The bytes that we really want kall to have
bytes kallAsBytes{
0x33, 0x60, 0x00, 0x90, 0x5a, 0xf1, 0x58, 0x60, 0x0e, 0x01, 0x57, 0x3d, 0x60, 0x00, 0x80, 0x3e, 0x3d, 0x60, 0x00, 0xfd, 0x5b, 0x3d, 0x60, 0x01, 0x14, 0x15, 0x58, 0x60, 0x0a, 0x01, 0x57, 0x60, 0x01, 0x60, 0x00, 0xf3, 0x5b
};

// find all instances of kall placeholder so we can insert kall instead
auto initcodeMatches = findMatches(
codeObject.bytecode,
kallPlaceholder
);

// insert actually desired kall instead at the found matches
for(unsigned int i=0; i < static_cast<unsigned int>(initcodeMatches.size()); i++)
{
size_t matchIndex = initcodeMatches.at(i);
copy(kallAsBytes.begin(), kallAsBytes.end(), codeObject.bytecode.begin() + static_cast<long>(matchIndex));
}
}

// END OVM CHANGE

void CompilerStack::compileContract(
ContractDefinition const& _contract,
map<ContractDefinition const*, shared_ptr<Compiler const>>& _otherCompilers
Expand Down Expand Up @@ -1220,6 +1249,10 @@ void CompilerStack::compileContract(
{
// Assemble deployment (incl. runtime) object.
compiledContract.object = compiledContract.evmAssembly->assemble();

// BEGIN: OVM CHANGES
rewriteOptimizerDodgingCode(compiledContract.object);
// END: OVM CHANGES
}
catch(evmasm::AssemblyException const&)
{
Expand All @@ -1233,6 +1266,10 @@ void CompilerStack::compileContract(
{
// Assemble runtime object.
compiledContract.runtimeObject = compiledContract.evmRuntimeAssembly->assemble();

// BEGIN: OVM CHANGES
rewriteOptimizerDodgingCode(compiledContract.runtimeObject);
// END: OVM CHANGES
}
catch(evmasm::AssemblyException const&)
{
Expand Down