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Do not overwrite allowMSizeOptimization

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This commit is contained in:
chriseth 2019-07-15 14:29:29 +02:00
parent 579bdaddb9
commit a0a0a34a21
4 changed files with 45 additions and 5 deletions
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1
Changelog.md
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@ -19,6 +19,7 @@ Compiler Features:
Bugfixes:
* View/Pure Checker: Properly detect state variable access through base class.
* Yul analyzer: Check availability of data objects already in analysis phase.
* Yul Optimizer: Fix an issue where memory-accessing code was removed even though ``msize`` was used in the program.

6
libyul/optimiser/UnusedPruner.cpp
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@ -119,15 +119,13 @@ void UnusedPruner::operator()(Block& _block)
void UnusedPruner::runUntilStabilised(
Dialect const& _dialect,
Block& _ast,
bool _allowMSizeOptization,
bool _allowMSizeOptimization,
set<YulString> const& _externallyUsedFunctions
)
{
_allowMSizeOptization = !SideEffectsCollector(_dialect, _ast).containsMSize();
while (true)
{
UnusedPruner pruner(_dialect, _ast, _allowMSizeOptization, _externallyUsedFunctions);
UnusedPruner pruner(_dialect, _ast, _allowMSizeOptimization, _externallyUsedFunctions);
pruner(_ast);
if (!pruner.shouldRunAgain())
return;

7
libyul/optimiser/UnusedPruner.h
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@ -34,6 +34,11 @@ struct Dialect;
* Optimisation stage that removes unused variables and functions and also
* removes side-effect-free expression statements.
*
* If msize is used, we cannot remove any statements that access memory.
* Because of that, the Unused Pruner should only be invoked on full ASTs,
* such that it can check for the presence of msize itself, or
* the `_allowMSizeOptimization` needs to be passed.
*
* Note that this does not remove circular references.
*
* Prerequisite: Disambiguator
@ -64,7 +69,7 @@ public:
static void runUntilStabilised(
Dialect const& _dialect,
Block& _ast,
bool _allowMSizeOptization,
bool _allowMSizeOptimization,
std::set<YulString> const& _externallyUsedFunctions = {}
);

36
test/libyul/yulOptimizerTests/stackCompressor/unusedPrunerWithMSize.yul Normal file
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@ -0,0 +1,36 @@
{
{
let _13_71 := 1
let _17_72 := pc()
let _22_75 := pc()
let _25_76 := pc()
let _30_80 := pc()
let _32_81 := pc()
// This should not be removed
pop(keccak256(1, 2))
let _104 := gt(not(_17_72), _13_71)
let _105 := 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
mstore(lt(or(gt(_13_71, or(or(gt(or(or(or(gt(or(gt(_105, _32_81), _13_71), _30_80), lt(or(_13_71, add(_25_76, _105)), _13_71)), _22_75), _13_71), _13_71), _104), _13_71)), _13_71), _13_71), _13_71)
foo_singlereturn_1()
}
function foo_singlereturn_1()
{
extcodecopy(1, msize(), 1, 1)
}
}
// ====
// step: stackCompressor
// ----
// {
// let _17_72 := pc()
// let _22_75 := pc()
// let _25_76 := pc()
// let _30_80 := pc()
// let _32_81 := pc()
// pop(keccak256(1, 2))
// let _105 := 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
// mstore(lt(or(gt(1, or(or(gt(or(or(or(gt(or(gt(_105, _32_81), 1), _30_80), lt(or(1, add(_25_76, _105)), 1)), _22_75), 1), 1), gt(not(_17_72), 1)), 1)), 1), 1), 1)
// foo_singlereturn_1()
// function foo_singlereturn_1()
// { extcodecopy(1, msize(), 1, 1) }
// }