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lll: disallow useless PUSHn in assembly #3070

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Merged
pirapira merged 1 commit into from
Oct 18, 2017
Merged

lll: disallow useless PUSHn in assembly #3070

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44 changes: 27 additions & 17 deletions liblll/CodeFragment.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,32 @@ void CodeFragment::finalise(CompilerState const& _cs)
}
}

namespace
{
/// Returns true iff the instruction is valid in "inline assembly".
bool validAssemblyInstruction(string us)
{
auto it = c_instructions.find(us);
return !(
it == c_instructions.end() ||
solidity::isPushInstruction(it->second)
);
}

/// Returns true iff the instruction is valid as a function.
bool validFunctionalInstruction(string us)
{
auto it = c_instructions.find(us);
return !(
it == c_instructions.end() ||
solidity::isPushInstruction(it->second) ||
solidity::isDupInstruction(it->second) ||
solidity::isSwapInstruction(it->second) ||
it->second == solidity::Instruction::JUMPDEST
);
}
}

CodeFragment::CodeFragment(sp::utree const& _t, CompilerState& _s, ReadCallback const& _readFile, bool _allowASM):
m_readFile(_readFile)
{
Expand Down Expand Up @@ -80,7 +106,7 @@ CodeFragment::CodeFragment(sp::utree const& _t, CompilerState& _s, ReadCallback
auto sr = _t.get<sp::basic_string<boost::iterator_range<char const*>, sp::utree_type::symbol_type>>();
string s(sr.begin(), sr.end());
string us = boost::algorithm::to_upper_copy(s);
if (_allowASM && c_instructions.count(us))
if (_allowASM && c_instructions.count(us) && validAssemblyInstruction(us))
m_asm.append(c_instructions.at(us));
else if (_s.defs.count(s))
m_asm.append(_s.defs.at(s).m_asm);
Expand Down Expand Up @@ -114,22 +140,6 @@ CodeFragment::CodeFragment(sp::utree const& _t, CompilerState& _s, ReadCallback
}
}

namespace
{
/// Returns true iff the instruction is valid as a function.
bool validFunctionalInstruction(string us)
{
auto it = c_instructions.find(us);
return !(
it == c_instructions.end() ||
solidity::isPushInstruction(it->second) ||
solidity::isDupInstruction(it->second) ||
solidity::isSwapInstruction(it->second) ||
it->second == solidity::Instruction::JUMPDEST
);
}
}

void CodeFragment::constructOperation(sp::utree const& _t, CompilerState& _s)
{
if (_t.tag() == 0 && _t.empty())
Expand Down
17 changes: 17 additions & 0 deletions test/liblll/Compiler.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -121,6 +121,23 @@ BOOST_AUTO_TEST_CASE(switch_inconsistent_return_count)
BOOST_CHECK(!successCompile(sourceCode));
}

BOOST_AUTO_TEST_CASE(disallowed_asm_instructions)
{
for (unsigned i = 1; i <= 32; i++)
BOOST_CHECK(!successCompile("(asm PUSH" + boost::lexical_cast<string>(i) + ")"));
}

BOOST_AUTO_TEST_CASE(disallowed_functional_asm_instructions)
{
for (unsigned i = 1; i <= 32; i++)
BOOST_CHECK(!successCompile("(PUSH" + boost::lexical_cast<string>(i) + ")"));
for (unsigned i = 1; i <= 16; i++)
BOOST_CHECK(!successCompile("(DUP" + boost::lexical_cast<string>(i) + ")"));
for (unsigned i = 1; i <= 16; i++)
BOOST_CHECK(!successCompile("(SWAP" + boost::lexical_cast<string>(i) + ")"));
BOOST_CHECK(!successCompile("(JUMPDEST)"));
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@pirapira pirapira Oct 13, 2017

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@winsvega wanted to use (JUMPDEST) in some tests. He and @axic need to talk.

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@axic axic Oct 13, 2017

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It can still be used via assembly: (asm JUMPDEST). See #3066.

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@pirapira pirapira Oct 13, 2017

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OK, then it's a non-issue.

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@axic axic Oct 13, 2017

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Also note it was removed a week ago or so, this PR removes pushnn from assembly and adds tests for the rest too.

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@winsvega winsvega Oct 13, 2017

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it is an issue. some tests rely on (JUMPDEST)
and we dont have a unit test that actually checks that all lll opcodes are actually supported by lllc version before running the test fillers.

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@winsvega winsvega Oct 13, 2017

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@pirapira what are the options?

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@pirapira pirapira Oct 13, 2017

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We build just parser of (opcode) to bytecode.

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@winsvega winsvega Oct 13, 2017

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the older version of solidity lllc works just like that. if you suggest to write a new parser...

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@axic axic Oct 13, 2017

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The older version of lllc is buggy and it produces unreliable output, at least output which we shouldn't rely on in testing the entire ecosystem with.

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@pirapira pirapira Oct 13, 2017

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@winsvega either fork an older lllc and fix the bugs, or create a new compiler.

}

BOOST_AUTO_TEST_SUITE_END()

}
Expand Down