Merge pull request #6730 from ethereum/generic-for-loop

For loop with generalized init-cond-post

test/tools/ossfuzz/protoToYul.cpp

@@ -616,7 +616,9 @@ void ProtoConverter::visit(FunctionCall const& _x)
 		visit(_x.call_zero());
 		break;
 	case FunctionCall::kCallMultidecl:
-		visit(_x.call_multidecl());
+		// Hack: Disallow (multi) variable declarations until scope extension is implemented for "for-init"
+		if (!m_inForInitScope)
+			visit(_x.call_multidecl());
 		break;
 	case FunctionCall::kCallMultiassign:
 		visit(_x.call_multiassign());
@@ -655,17 +657,38 @@ void ProtoConverter::visit(StoreFunc const& _x)
 }
 
 void ProtoConverter::visit(ForStmt const& _x)
+{
+	bool wasInForBody = m_inForBodyScope;
+	bool wasInForInit = m_inForInitScope;
+	m_inForBodyScope = false;
+	m_inForInitScope = true;
+	m_output << "for ";
+	visit(_x.for_init());
+	m_inForInitScope = false;
+	visit(_x.for_cond());
+	visit(_x.for_post());
+	m_inForBodyScope = true;
+	visit(_x.for_body());
+	m_inForBodyScope = wasInForBody;
+	m_inForInitScope = wasInForInit;
+}
+
+void ProtoConverter::visit(BoundedForStmt const& _x)
 {
 	// Boilerplate for loop that limits the number of iterations to a maximum of 4.
-	// TODO: Generalize for loop init, condition, and post blocks.
 	std::string loopVarName("i_" + std::to_string(m_numNestedForLoops++));
 	m_output << "for { let " << loopVarName << " := 0 } "
-		<< "lt(" << loopVarName << ", 0x60) "
+	       << "lt(" << loopVarName << ", 0x60) "
-		<< "{ " << loopVarName << " := add(" << loopVarName << ", 0x20) } ";
+	       << "{ " << loopVarName << " := add(" << loopVarName << ", 0x20) } ";
-	m_inForScope.push(true);
+	// Store previous for body scope
+	bool wasInForBody = m_inForBodyScope;
+	bool wasInForInit = m_inForInitScope;
+	m_inForBodyScope = true;
+	m_inForInitScope = false;
 	visit(_x.for_body());
-	m_inForScope.pop();
+	// Restore previous for body scope and init
-	--m_numNestedForLoops;
+	m_inForBodyScope = wasInForBody;
+	m_inForInitScope = wasInForInit;
 }
 
 void ProtoConverter::visit(CaseStmt const& _x)
@@ -765,7 +788,9 @@ void ProtoConverter::visit(Statement const& _x)
 	switch (_x.stmt_oneof_case())
 	{
 	case Statement::kDecl:
-		visit(_x.decl());
+		// Hack: Disallow (multi) variable declarations until scope extension is implemented for "for-init"
+		if (!m_inForInitScope)
+			visit(_x.decl());
 		break;
 	case Statement::kAssignment:
 		visit(_x.assignment());
@@ -782,15 +807,18 @@ void ProtoConverter::visit(Statement const& _x)
 	case Statement::kForstmt:
 		visit(_x.forstmt());
 		break;
+	case Statement::kBoundedforstmt:
+		visit(_x.boundedforstmt());
+		break;
 	case Statement::kSwitchstmt:
 		visit(_x.switchstmt());
 		break;
 	case Statement::kBreakstmt:
-		if (m_inForScope.top())
+		if (m_inForBodyScope)
 			m_output << "break\n";
 		break;
 	case Statement::kContstmt:
-		if (m_inForScope.top())
+		if (m_inForBodyScope)
 			m_output << "continue\n";
 		break;
 	case Statement::kLogFunc:

test/tools/ossfuzz/protoToYul.h

@@ -42,9 +42,10 @@ public:
 	{
 		m_numLiveVars = 0;
 		m_numVarsPerScope.push(m_numLiveVars);
-		m_numNestedForLoops = 0;
-		m_inForScope.push(false);
 		m_numFunctionSets = 0;
+		m_inForBodyScope = false;
+		m_inForInitScope = false;
+		m_numNestedForLoops = 0;
 	}
 	ProtoConverter(ProtoConverter const&) = delete;
 	ProtoConverter(ProtoConverter&&) = delete;
@@ -69,6 +70,7 @@ private:
 	void visit(Statement const&);
 	void visit(FunctionDefinition const&);
 	void visit(ForStmt const&);
+	void visit(BoundedForStmt const&);
 	void visit(CaseStmt const&);
 	void visit(SwitchStmt const&);
 	void visit(TernaryOp const&);
@@ -131,9 +133,6 @@ private:
 	std::stack<unsigned> m_numVarsPerScope;
 	// Number of live variables in function scope
 	unsigned m_numLiveVars;
-	// Number of nested for loops for loop index referencing
-	unsigned m_numNestedForLoops;
-	std::stack<bool> m_inForScope;
 	// Set that is used for deduplicating switch case literals
 	std::stack<std::set<dev::u256>> m_switchLiteralSetPerScope;
 	// Total number of function sets. A function set contains one function of each type defined by
@@ -146,6 +145,12 @@ private:
 	// mod input/output parameters impose an upper bound on the number of input/output parameters a function may have.
 	static unsigned constexpr modInputParams = 5;
 	static unsigned constexpr modOutputParams = 5;
+	// predicate to keep track of for body scope
+	bool m_inForBodyScope;
+	// Index used for naming loop variable of bounded for loops
+	unsigned m_numNestedForLoops;
+	// predicate to keep track of for loop init scope
+	bool m_inForInitScope;
 };
 }
 }

test/tools/ossfuzz/yulProto.proto

@@ -256,8 +256,15 @@ message IfStmt {
   required Block if_body = 2;
 }
 
+message BoundedForStmt {
+  required Block for_body = 1;
+}
+
 message ForStmt {
   required Block for_body = 1;
+  required Block for_init = 2;
+  required Block for_post = 3;
+  required Expression for_cond = 4;
 }
 
 message CaseStmt {
@@ -324,6 +331,7 @@ message Statement {
     ExtCodeCopy         extcode_copy    = 12;
     TerminatingStmt     terminatestmt   = 13;
     FunctionCall        functioncall    = 14;
+    BoundedForStmt      boundedforstmt  = 15;
   }
 }