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Optimizer: Clear state for JUMPDESTs.

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This commit is contained in:
chriseth 2016-11-22 14:55:09 +01:00
parent aa48008cc7
commit 7fb7d5ae39
3 changed files with 50 additions and 36 deletions
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5
Changelog.md
View File

@ -1,3 +1,8 @@
### 0.4.6 (2016-11-22)
Bugfixes:
* Optimizer: Knowledge about state was not correctly cleared for JUMPDESTs
### 0.4.5 (2016-11-21)
Features:

61
libevmasm/Assembly.cpp
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@ -360,46 +360,35 @@ map<u256, u256> Assembly::optimiseInternal(bool _enable, bool _isCreation, size_
auto iter = m_items.begin();
while (iter != m_items.end())
{
auto end = iter;
while (end != m_items.end())
if (SemanticInformation::altersControlFlow(*end++))
break;
KnownState emptyState;
CommonSubexpressionEliminator eliminator(emptyState);
auto blockIter = iter;
auto const blockEnd = end;
while (blockIter < blockEnd)
auto orig = iter;
iter = eliminator.feedItems(iter, m_items.end());
bool shouldReplace = false;
AssemblyItems optimisedChunk;
try
{
auto orig = blockIter;
blockIter = eliminator.feedItems(blockIter, blockEnd);
bool shouldReplace = false;
AssemblyItems optimisedChunk;
try
{
optimisedChunk = eliminator.getOptimizedItems();
shouldReplace = (optimisedChunk.size() < size_t(blockIter - orig));
}
catch (StackTooDeepException const&)
{
// This might happen if the opcode reconstruction is not as efficient
// as the hand-crafted code.
}
catch (ItemNotAvailableException const&)
{
// This might happen if e.g. associativity and commutativity rules
// reorganise the expression tree, but not all leaves are available.
}
if (shouldReplace)
{
count++;
optimisedItems += optimisedChunk;
}
else
copy(orig, blockIter, back_inserter(optimisedItems));
optimisedChunk = eliminator.getOptimizedItems();
shouldReplace = (optimisedChunk.size() < size_t(iter - orig));
}
iter = end;
catch (StackTooDeepException const&)
{
// This might happen if the opcode reconstruction is not as efficient
// as the hand-crafted code.
}
catch (ItemNotAvailableException const&)
{
// This might happen if e.g. associativity and commutativity rules
// reorganise the expression tree, but not all leaves are available.
}
if (shouldReplace)
{
count++;
optimisedItems += optimisedChunk;
}
else
copy(orig, iter, back_inserter(optimisedItems));
}
if (optimisedItems.size() < m_items.size())
{

20
test/libsolidity/SolidityOptimizer.cpp
View File

@ -1246,6 +1246,26 @@ BOOST_AUTO_TEST_CASE(dead_code_elimination_across_assemblies)
compareVersions("test()");
}
BOOST_AUTO_TEST_CASE(invalid_state_at_control_flow_join)
{
char const* sourceCode = R"(
contract Test {
uint256 public totalSupply = 100;
function f() returns (uint r) {
if (false)
r = totalSupply;
totalSupply -= 10;
}
function test() returns (uint) {
f();
return this.totalSupply();
}
}
)";
compileBothVersions(sourceCode);
compareVersions("test()");
}
BOOST_AUTO_TEST_SUITE_END()
}