cerc-io/solidity
16
0
Fork 0
mirror of https://github.com/ethereum/solidity synced 2023-10-03 13:03:40 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Merge pull request #2545 from benjaminion/lll-alloc-updated

Browse Source 
LLL: alloc issues round-up
This commit is contained in:
Alex Beregszaszi 2017-07-11 22:44:41 +02:00 committed by GitHub
commit 699a3724ae
3 changed files with 79 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
liblll/CodeFragment.cpp
View File

@ -523,14 +523,30 @@ void CodeFragment::constructOperation(sp::utree const& _t, CompilerState& _s)
requireSize(1);
requireDeposit(0, 1);
m_asm.append(Instruction::MSIZE);
m_asm.append(u256(0));
// (alloc N):
// - Evaluates to (msize) before the allocation - the start of the allocated memory
// - Does not allocate memory when N is zero
// - Size of memory allocated is N bytes rounded up to a multiple of 32
// - Uses MLOAD to expand MSIZE to avoid modifying memory.
auto end = m_asm.newTag();
m_asm.append(Instruction::MSIZE); // Result will be original top of memory
m_asm.append(code[0].m_asm, 1); // The alloc argument N
m_asm.append(Instruction::DUP1);
m_asm.append(Instruction::ISZERO);// (alloc 0) does not change MSIZE
m_asm.appendJumpI(end);
m_asm.append(u256(1));
m_asm.append(code[0].m_asm, 1);
m_asm.append(Instruction::MSIZE);
m_asm.append(Instruction::DUP2); // Copy N
m_asm.append(Instruction::SUB); // N-1
m_asm.append(u256(0x1f)); // Bit mask
m_asm.append(Instruction::NOT); // Invert
m_asm.append(Instruction::AND); // Align N-1 on 32 byte boundary
m_asm.append(Instruction::MSIZE); // MSIZE is cheap
m_asm.append(Instruction::ADD);
m_asm.append(Instruction::SUB);
m_asm.append(Instruction::MSTORE8);
m_asm.append(Instruction::MLOAD); // Updates MSIZE
m_asm.append(Instruction::POP); // Discard the result of the MLOAD
m_asm.append(end);
m_asm.append(Instruction::POP); // Discard duplicate N
_s.usedAlloc = true;
}

2
liblll/CompilerState.cpp
View File

@ -46,6 +46,8 @@ void CompilerState::populateStandard()
{
static const string s = "{"
"(def 'panic () (asm INVALID))"
// Alternative macro version of alloc, which is currently implemented in the parser
// "(def 'alloc (n) (raw (msize) (when n (pop (mload (+ (msize) (& (- n 1) (~ 0x1f))))))))"
"(def 'allgas (- (gas) 21))"
"(def 'send (to value) (call allgas to value 0 0 0 0))"
"(def 'send (gaslimit to value) (call gaslimit to value 0 0 0 0))"

55
test/liblll/EndToEndTest.cpp
View File

@ -467,6 +467,61 @@ BOOST_AUTO_TEST_CASE(send_three_args)
BOOST_CHECK(balanceAt(Address(0xdead)) == 42);
}
// Regression test for edge case that previously failed
BOOST_AUTO_TEST_CASE(alloc_zero)
{
char const* sourceCode = R"(
(returnlll
(seq
(mstore 0x00 (~ 0))
(alloc 0)
(return 0x00 0x20)))
)";
compileAndRun(sourceCode);
BOOST_CHECK(callFallback() == encodeArgs(u256(-1)));
}
BOOST_AUTO_TEST_CASE(alloc_size)
{
char const* sourceCode = R"(
(returnlll
(seq
(mstore 0x00 0) ; reserve space for the result of the alloc
(mstore 0x00 (alloc (calldataload 0x04)))
(return (- (msize) (mload 0x00)))))
)";
compileAndRun(sourceCode);
BOOST_CHECK(callContractFunction("test()", 0) == encodeArgs(u256(0)));
BOOST_CHECK(callContractFunction("test()", 1) == encodeArgs(u256(32)));
BOOST_CHECK(callContractFunction("test()", 32) == encodeArgs(u256(32)));
BOOST_CHECK(callContractFunction("test()", 33) == encodeArgs(u256(64)));
}
BOOST_AUTO_TEST_CASE(alloc_start)
{
char const* sourceCode = R"(
(returnlll
(seq
(mstore 0x40 0) ; Set initial MSIZE to 0x60
(return (alloc 1))))
)";
compileAndRun(sourceCode);
BOOST_CHECK(callFallback() == encodeArgs(96));
}
BOOST_AUTO_TEST_CASE(alloc_with_variable)
{
char const* sourceCode = R"(
(returnlll
(seq
(set 'x (alloc 1))
(mstore8 @x 42) ; ASCII '*'
(return @x 0x20)))
)";
compileAndRun(sourceCode);
BOOST_CHECK(callFallback() == encodeArgs("*"));
}
BOOST_AUTO_TEST_CASE(msg_six_args)
{
char const* sourceCode = R"(