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Changes to how function calls are generated.

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This commit is contained in:
Bhargava Shastry 2021-02-07 19:02:01 +01:00
parent 81c7b30a6a
commit 1709b2924b
3 changed files with 65 additions and 203 deletions
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204
test/tools/ossfuzz/protoToYul.cpp
View File

@ -173,20 +173,6 @@ bool ProtoConverter::varDeclAvailable()
}
}
bool ProtoConverter::functionCallNotPossible(FunctionCall_Returns _type)
{
return _type == FunctionCall::SINGLE ||
(_type == FunctionCall::MULTIASSIGN && !varDeclAvailable());
}
unsigned ProtoConverter::numVarsInScope()
{
if (m_inFunctionDef)
return static_cast<unsigned>(m_currentFuncVars.size());
else
return static_cast<unsigned>(m_currentGlobalVars.size());
}
void ProtoConverter::visit(VarRef const& _x)
{
if (m_inFunctionDef)
@ -238,10 +224,11 @@ void ProtoConverter::visit(Expression const& _x)
visit(_x.nop());
break;
case Expression::kFuncExpr:
// FunctionCall must return a single value, otherwise
// we output a trivial expression "1".
if (_x.func_expr().ret() == FunctionCall::SINGLE)
visit(_x.func_expr());
if (auto v = functionExists(NumFunctionReturns::Single); v.has_value())
{
string functionName = v.value();
visit(_x.func_expr(), functionName, true);
}
else
m_output << dictionaryToken();
break;
@ -905,20 +892,6 @@ void ProtoConverter::visitFunctionInputParams(FunctionCall const& _x, unsigned _
}
}
bool ProtoConverter::functionValid(FunctionCall_Returns _type, unsigned _numOutParams)
{
switch (_type)
{
case FunctionCall::ZERO:
return _numOutParams == 0;
case FunctionCall::SINGLE:
return _numOutParams == 1;
case FunctionCall::MULTIDECL:
case FunctionCall::MULTIASSIGN:
return _numOutParams > 1;
}
}
void ProtoConverter::convertFunctionCall(
FunctionCall const& _x,
string const& _name,
@ -944,130 +917,52 @@ vector<string> ProtoConverter::createVarDecls(unsigned _start, unsigned _end, bo
return varsVec;
}
void ProtoConverter::visit(FunctionCall const& _x)
optional<string> ProtoConverter::functionExists(NumFunctionReturns _numReturns)
{
bool functionAvailable = m_functionSigMap.size() > 0;
unsigned numInParams, numOutParams;
string funcName;
FunctionCall_Returns funcType = _x.ret();
if (functionAvailable)
for (auto const& item: m_functionSigMap)
if (_numReturns == NumFunctionReturns::None || _numReturns == NumFunctionReturns::Single)
{
if (item.second.second == static_cast<unsigned>(_numReturns))
return item.first;
}
else
{
if (item.second.second >= static_cast<unsigned>(_numReturns))
return item.first;
}
return nullopt;
}
void ProtoConverter::visit(FunctionCall const& _x, string const& _functionName, bool _expression)
{
yulAssert(m_functionSigMap.count(_functionName), "Proto fuzzer: Invalid function.");
auto ret = m_functionSigMap.at(_functionName);
unsigned numInParams = ret.first;
unsigned numOutParams = ret.second;
if (numOutParams == 0)
{
yulAssert(m_functions.size() > 0, "Proto fuzzer: No function in scope");
funcName = m_functions[_x.func_index() % m_functions.size()];
auto ret = m_functionSigMap.at(funcName);
numInParams = ret.first;
numOutParams = ret.second;
convertFunctionCall(_x, _functionName, numInParams);
return;
}
else
{
// If there are no functions available, calls to functions that
// return a single value may be replaced by a dictionary token.
if (funcType == FunctionCall::SINGLE)
m_output << dictionaryToken();
return;
}
// If function selected for function call does not meet interface
// requirements (num output values) for the function type
// specified, then we return early unless it is a function call
// that returns a single value (which may be replaced by a
// dictionary token.
if (!functionValid(funcType, numOutParams))
{
if (funcType == FunctionCall::SINGLE)
m_output << dictionaryToken();
return;
}
// If we are here, it means that we have at least one valid
// function for making the function call
switch (funcType)
{
case FunctionCall::ZERO:
convertFunctionCall(_x, funcName, numInParams);
break;
case FunctionCall::SINGLE:
// Since functions that return a single value are used as expressions
// we do not print a newline because it is done by the expression
// visitor.
convertFunctionCall(_x, funcName, numInParams, /*newLine=*/false);
break;
case FunctionCall::MULTIDECL:
{
// Ensure that the chosen function returns at most 4 values
yulAssert(
numOutParams <= 4,
"Proto fuzzer: Function call with too many output params encountered."
);
// Obtain variable name suffix
unsigned startIdx = counter();
vector<string> varsVec = createVarDecls(
startIdx,
startIdx + numOutParams,
/*isAssignment=*/true
);
// Create RHS of multi var decl
convertFunctionCall(_x, funcName, numInParams);
// Add newly minted vars in the multidecl statement to current scope
addVarsToScope(varsVec);
break;
}
case FunctionCall::MULTIASSIGN:
// Ensure that the chosen function returns at most 4 values
yulAssert(
numOutParams <= 4,
"Proto fuzzer: Function call with too many output params encountered."
);
// Return early if numOutParams > number of available variables
if (numOutParams > numVarsInScope())
return;
// Copy variables in scope in order to prevent repeated references
vector<string> variables;
if (m_inFunctionDef)
for (auto var: m_currentFuncVars)
variables.push_back(*var);
else
for (auto var: m_currentGlobalVars)
variables.push_back(*var);
auto refVar = [](vector<string>& _var, unsigned _rand, bool _comma = true) -> string
{
auto index = _rand % _var.size();
string ref = _var[index];
_var.erase(_var.begin() + index);
if (_comma)
ref += ", ";
return ref;
};
// Convert LHS of multi assignment
// We reverse the order of out param visits since the order does not matter.
// This helps reduce the size of this switch statement.
switch (numOutParams)
yulAssert(numOutParams > 0, "");
vector<string> varsVec;
if (!_expression)
{
case 4:
m_output << refVar(variables, _x.out_param4().varnum());
[[fallthrough]];
case 3:
m_output << refVar(variables, _x.out_param3().varnum());
[[fallthrough]];
case 2:
m_output << refVar(variables, _x.out_param2().varnum());
m_output << refVar(variables, _x.out_param1().varnum(), false);
break;
default:
yulAssert(false, "Proto fuzzer: Function call with too many or too few input parameters.");
break;
// Obtain variable name suffix
unsigned startIdx = counter();
varsVec = createVarDecls(
startIdx,
startIdx + numOutParams,
/*isAssignment=*/true
);
}
m_output << " := ";
// Convert RHS of multi assignment
convertFunctionCall(_x, funcName, numInParams);
break;
convertFunctionCall(_x, _functionName, numInParams);
// Add newly minted vars in the multidecl statement to current scope
if (!_expression)
addVarsToScope(varsVec);
}
}
@ -1463,10 +1358,13 @@ void ProtoConverter::visit(Statement const& _x)
visit(_x.terminatestmt());
break;
case Statement::kFunctioncall:
// Return early if a function call cannot be created
if (functionCallNotPossible(_x.functioncall().ret()))
return;
visit(_x.functioncall());
if (!m_functionSigMap.empty())
{
unsigned index = counter() % m_functionSigMap.size();
auto iter = m_functionSigMap.begin();
advance(iter, index);
visit(_x.functioncall(), iter->first);
}
break;
case Statement::kFuncdef:
if (_x.funcdef().block().statements_size() > 0)

39
test/tools/ossfuzz/protoToYul.h
View File

@ -102,7 +102,7 @@ private:
void visit(RetRevStmt const&);
void visit(SelfDestructStmt const&);
void visit(TerminatingStmt const&);
void visit(FunctionCall const&);
void visit(FunctionCall const&, std::string const&, bool _expression = false);
void visit(FunctionDef const&);
void visit(PopStmt const&);
void visit(LeaveStmt const&);
@ -125,8 +125,6 @@ private:
void closeFunctionScope();
/// Adds @a _vars to current scope
void addVarsToScope(std::vector<std::string> const& _vars);
/// @returns number of variables that are in scope
unsigned numVarsInScope();
std::string createHex(std::string const& _hexBytes);
@ -140,9 +138,9 @@ private:
/// alphabets nor digits from it and returns the said string.
static std::string createAlphaNum(std::string const& _strBytes);
enum class NumFunctionReturns
enum class NumFunctionReturns: unsigned
{
None,
None = 0,
Single,
Multiple
};
@ -176,34 +174,6 @@ private:
/// in scope
bool varDeclAvailable();
/// Return true if a function call cannot be made, false otherwise.
/// @param _type is an enum denoting the type of function call. It
/// can be one of NONE, SINGLE, MULTIDECL, MULTIASSIGN.
/// NONE -> Function call does not return a value
/// SINGLE -> Function call returns a single value
/// MULTIDECL -> Function call returns more than one value
/// and it is used to create a multi declaration
/// statement
/// MULTIASSIGN -> Function call returns more than one value
/// and it is used to create a multi assignment
/// statement
/// @return True if the function call cannot be created for one of the
/// following reasons
// - It is a SINGLE function call (we reserve SINGLE functions for
// expressions)
// - It is a MULTIASSIGN function call and we do not have any
// variables available for assignment.
bool functionCallNotPossible(FunctionCall_Returns _type);
/// Checks if function call of type @a _type returns the correct number
/// of values.
/// @param _type Function call type of the function being checked
/// @param _numOutParams Number of values returned by the function
/// being checked
/// @return true if the function returns the correct number of values,
/// false otherwise
bool functionValid(FunctionCall_Returns _type, unsigned _numOutParams);
/// Converts protobuf function call to a Yul function call and appends
/// it to output stream.
/// @param _x Protobuf function call
@ -295,6 +265,9 @@ private:
/// enum of type Program_Version
static solidity::langutil::EVMVersion evmVersionMapping(Program_Version const& _x);
/// @returns name of Yul function with return type of @param _numReturns.
std::optional<std::string> functionExists(NumFunctionReturns _numReturns);
/// Returns a monotonically increasing counter that starts from zero.
unsigned counter()
{

25
test/tools/ossfuzz/yulProto.proto
View File

@ -58,23 +58,14 @@ message Create {
}
message FunctionCall {
enum Returns {
ZERO = 1;
SINGLE = 2;
MULTIDECL = 3;
MULTIASSIGN = 4;
}
required Returns ret = 1;
// Indexes an existing function
required uint32 func_index = 2;
required Expression in_param1 = 3;
required Expression in_param2 = 4;
required Expression in_param3 = 5;
required Expression in_param4 = 6;
required VarRef out_param1 = 7;
required VarRef out_param2 = 8;
required VarRef out_param3 = 9;
required VarRef out_param4 = 10;
required Expression in_param1 = 1;
required Expression in_param2 = 2;
required Expression in_param3 = 3;
required Expression in_param4 = 4;
required VarRef out_param1 = 5;
required VarRef out_param2 = 6;
required VarRef out_param3 = 7;
required VarRef out_param4 = 8;
}
message TypedVarDecl {