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chrisethchriseth
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Do not use named function labels if function names are not unique.
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6 files changed

+137
-2
lines changed

6 files changed

+137
-2
lines changed

‎Changelog.md

+1
Original file line numberDiff line numberDiff line change
@@ -19,6 +19,7 @@ Bugfixes:
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* Commandline Interface: Don't return zero exit code when writing linked files to disk fails.
2020
* SMTChecker: Fix internal error in magic type access (``block``, ``msg``, ``tx``).
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* TypeChecker: Fix internal error when using user defined value types in public library functions.
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* Yul Assembler: Fix internal error when function names are not unique.
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* Yul IR Generator: Do not output empty switches/if-bodies for empty contracts.
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‎libyul/backends/evm/EVMObjectCompiler.cpp

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@@ -30,6 +30,30 @@
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using namespace solidity::yul;
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using namespace std;
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namespace
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{
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class AreFunctionNamesUnique: ASTWalker
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{
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public:
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static bool check(Block& _block)
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{
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AreFunctionNamesUnique instance;
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instance(_block);
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return instance.m_unique;
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}
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private:
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using ASTWalker::operator();
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void operator()(FunctionDefinition const& _functionDefinition) override
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{
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ASTWalker::operator()(_functionDefinition);
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if (!m_functionNames.insert(_functionDefinition.name).second)
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m_unique = false;
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}
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bool m_unique = true;
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std::set<YulString> m_functionNames;
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};
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}
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void EVMObjectCompiler::compile(Object& _object, AbstractAssembly& _assembly, EVMDialect const& _dialect, bool _optimize)
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{
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EVMObjectCompiler compiler(_assembly, _dialect);
@@ -62,6 +86,10 @@ void EVMObjectCompiler::run(Object& _object, bool _optimize)
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yulAssert(_object.analysisInfo, "No analysis info.");
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yulAssert(_object.code, "No code.");
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// We cannot use named labels if the function names are not unique.
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bool useNamedLabelsForFunctions = AreFunctionNamesUnique::check(*_object.code);
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// We do not catch and re-throw the stack too deep exception here because it is a YulException,
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// which should be native to this part of the code.
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CodeTransform transform{
@@ -72,7 +100,7 @@ void EVMObjectCompiler::run(Object& _object, bool _optimize)
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context,
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_optimize,
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{},
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true /* _useNamedLabelsForFunctions */
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useNamedLabelsForFunctions
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};
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transform(*_object.code);
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if (!transform.stackErrors().empty())

‎libyul/optimiser/Disambiguator.h

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@@ -55,7 +55,7 @@ class Disambiguator: public ASTCopier
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void enterScope(Block const& _block) override;
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void leaveScope(Block const& _block) override;
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void enterFunction(FunctionDefinition const& _function) override;
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void leaveFunction(FunctionDefinition const& _function) override;
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void leaveFunction (FunctionDefinition const& _function) override;
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YulString translateIdentifier(YulString _name) override;
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void enterScopeInternal(Scope& _scope);

‎test/cmdlineTests/yul_function_name_clashes/args

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@@ -0,0 +1 @@
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--strict-assembly

‎test/cmdlineTests/yul_function_name_clashes/input.yul

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@@ -0,0 +1,17 @@
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object "object" {
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code {
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let a
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let b
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{
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function z() -> y
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{ y := calldataload(0) }
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a := z()
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}
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{
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function z() -> y
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{ y := calldataload(0x20) }
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b := z()
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}
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sstore(a, b)
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}
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}

‎test/cmdlineTests/yul_function_name_clashes/output

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@@ -0,0 +1,88 @@
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======= yul_function_name_clashes/input.yul (EVM) =======
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Pretty printed source:
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object "object" {
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code {
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let a
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let b
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{
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function z() -> y
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{ y := calldataload(0) }
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a := z()
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}
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{
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function z() -> y
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{ y := calldataload(0x20) }
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b := z()
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}
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sstore(a, b)
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}
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}
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Binary representation:
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600080600f565b60008035905090565b60156006565b91506025565b6000602035905090565b602b601b565b90508082555050
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Text representation:
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/* "yul_function_name_clashes/input.yul":37:42 */
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0x00
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/* "yul_function_name_clashes/input.yul":51:56 */
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dup1
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/* "yul_function_name_clashes/input.yul":79:133 */
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jump(tag_2)
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tag_1:
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/* "yul_function_name_clashes/input.yul":95:96 */
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0x00
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/* "yul_function_name_clashes/input.yul":129:130 */
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dup1
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/* "yul_function_name_clashes/input.yul":116:131 */
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calldataload
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/* "yul_function_name_clashes/input.yul":111:131 */
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swap1
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pop
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/* "yul_function_name_clashes/input.yul":79:133 */
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swap1
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jump // out
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tag_2:
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/* "yul_function_name_clashes/input.yul":151:154 */
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tag_4
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tag_1
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jump // in
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tag_4:
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/* "yul_function_name_clashes/input.yul":146:154 */
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swap2
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pop
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/* "yul_function_name_clashes/input.yul":187:244 */
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jump(tag_6)
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tag_5:
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/* "yul_function_name_clashes/input.yul":203:204 */
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0x00
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/* "yul_function_name_clashes/input.yul":237:241 */
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0x20
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/* "yul_function_name_clashes/input.yul":224:242 */
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calldataload
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/* "yul_function_name_clashes/input.yul":219:242 */
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swap1
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pop
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/* "yul_function_name_clashes/input.yul":187:244 */
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swap1
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jump // out
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tag_6:
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/* "yul_function_name_clashes/input.yul":262:265 */
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tag_8
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tag_5
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jump // in
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tag_8:
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/* "yul_function_name_clashes/input.yul":257:265 */
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swap1
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pop
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/* "yul_function_name_clashes/input.yul":294:295 */
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dup1
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/* "yul_function_name_clashes/input.yul":291:292 */
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dup3
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/* "yul_function_name_clashes/input.yul":284:296 */
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sstore
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/* "yul_function_name_clashes/input.yul":27:302 */
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pop
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pop

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