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Decode dynamic data.

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This commit is contained in:
chriseth
2018-03-21 14:53:29 +00:00
committed by Alex Beregszaszi
parent cc2f71e4ac
commit c2709a2d8e
5 changed files with 55 additions and 20 deletions
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libsolidity/codegen/ExpressionCompiler.cpp
+44 -17
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@@ -1618,22 +1618,27 @@ void ExpressionCompiler::appendExternalFunctionCall(
m_context.experimentalFeatureActive(ExperimentalFeature::V050) &&
m_context.evmVersion().hasStaticCall();
bool allowDynamicTypes = false; // @TODO
bool haveReturndatacopy = m_context.evmVersion().supportsReturndata();
unsigned retSize = 0;
TypePointers returnTypes;
if (returnSuccessCondition)
retSize = 0; // return value actually is success condition
else if (allowDynamicTypes)
else if (haveReturndatacopy)
returnTypes = _functionType.returnParameterTypes();
else
{
returnTypes = _functionType.returnParameterTypesWithoutDynamicTypes();
for (auto const& retType: returnTypes)
bool dynamicReturnSize = false;
for (auto const& retType: returnTypes)
if (retType->isDynamicallyEncoded())
{
solAssert(!retType->isDynamicallySized(), "Unable to return dynamic type from external call.");
retSize += retType->calldataEncodedSize();
solAssert(haveReturndatacopy, "");
dynamicReturnSize = true;
retSize = 0;
break;
}
}
else
retSize += retType->calldataEncodedSize();
// Evaluate arguments.
TypePointers argumentTypes;
@@ -1834,17 +1839,39 @@ void ExpressionCompiler::appendExternalFunctionCall(
else if (!returnTypes.empty())
{
utils().fetchFreeMemoryPointer();
bool memoryNeeded = false;
for (auto const& retType: returnTypes)
{
utils().loadFromMemoryDynamic(*retType, false, true, true);
if (dynamic_cast<ReferenceType const*>(retType.get()))
memoryNeeded = true;
}
if (memoryNeeded)
utils().storeFreeMemoryPointer();
// Stack: return_data_start
// The old decoder did not allocate any memory (i.e. did not touch the free
// memory pointer), but kept references to the return data for
// (statically-sized) arrays
bool needToUpdateFreeMemoryPtr = false;
if (dynamicReturnSize || m_context.experimentalFeatureActive(ExperimentalFeature::ABIEncoderV2))
needToUpdateFreeMemoryPtr = true;
else
m_context << Instruction::POP;
for (auto const& retType: returnTypes)
if (dynamic_cast<ReferenceType const*>(retType.get()))
needToUpdateFreeMemoryPtr = true;
// Stack: return_data_start
if (dynamicReturnSize)
{
solAssert(haveReturndatacopy, "");
m_context.appendInlineAssembly("{ returndatacopy(return_data_start, 0, returndatasize()) }", {"return_data_start"});
}
else
solAssert(retSize > 0, "");
// Always use the actual return length, and not our calculated expected length, if returndatacopy is supported.
// This ensures it can catch badly formatted input from external calls.
m_context << (haveReturndatacopy ? eth::AssemblyItem(Instruction::RETURNDATASIZE) : u256(retSize));
// Stack: return_data_start return_data_size
if (needToUpdateFreeMemoryPtr)
m_context.appendInlineAssembly(R"({
// round size to the next multiple of 32
let newMem := add(start, and(add(size, 0x1f), not(0x1f)))
mstore(0x40, newMem)
})", {"start", "size"});
utils().abiDecode(returnTypes, true, true);
}
}