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Allocate one byte per memory byte array element instead of 32.

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This commit is contained in:
chriseth 2017-10-11 12:28:21 +02:00
parent 7989fc4c35
commit 6001bd1406
3 changed files with 34 additions and 2 deletions
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1
Changelog.md
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@ -13,6 +13,7 @@ Features:
* Type Checker: Require ``storage`` or ``memory`` keyword for local variables as experimental 0.5.0 feature.
Bugfixes:
* Code Generator: Allocate one byte per memory byte array element instead of 32.
* Optimizer: Remove unused stack computation results.
* Parser: Fix source location of VariableDeclarationStatement.
* Type Checker: Properly check array length and don't rely on an assertion in code generation.

11
libsolidity/codegen/ExpressionCompiler.cpp
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@ -858,8 +858,15 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
m_context << Instruction::DUP1 << Instruction::DUP3 << Instruction::MSTORE;
// Stack: memptr requested_length
// update free memory pointer
m_context << Instruction::DUP1 << arrayType.baseType()->memoryHeadSize();
m_context << Instruction::MUL << u256(32) << Instruction::ADD;
m_context << Instruction::DUP1;
// Stack: memptr requested_length requested_length
if (arrayType.isByteArray())
// Round up to multiple of 32
m_context << u256(31) << Instruction::ADD << u256(31) << Instruction::NOT << Instruction::AND;
else
m_context << arrayType.baseType()->memoryHeadSize() << Instruction::MUL;
// stacK: memptr requested_length data_size
m_context << u256(32) << Instruction::ADD;
m_context << Instruction::DUP3 << Instruction::ADD;
utils().storeFreeMemoryPointer();
// Stack: memptr requested_length

24
test/libsolidity/SolidityEndToEndTest.cpp
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@ -7309,6 +7309,30 @@ BOOST_AUTO_TEST_CASE(create_memory_array)
ABI_CHECK(callContractFunction("f()"), encodeArgs(string("A"), u256(8), u256(4), string("B")));
}
BOOST_AUTO_TEST_CASE(create_memory_array_allocation_size)
{
// Check allocation size of byte array. Should be 32 plus length rounded up to next
// multiple of 32
char const* sourceCode = R"(
contract C {
function f() pure returns (uint d1, uint d2, uint d3) {
bytes memory b1 = new bytes(31);
bytes memory b2 = new bytes(32);
bytes memory b3 = new bytes(256);
bytes memory b4 = new bytes(31);
assembly {
d1 := sub(b2, b1)
d2 := sub(b3, b2)
d3 := sub(b4, b3)
}
}
}
)";
compileAndRun(sourceCode);
ABI_CHECK(callContractFunction("f()"), encodeArgs(0x40, 0x40, 0x20 + 256));
}
BOOST_AUTO_TEST_CASE(memory_arrays_of_various_sizes)
{
// Computes binomial coefficients the chinese way