Fix ExpressionRunner issues found by the fuzzer (#2790)

Fixes #2788 found by the fuzzer, introduced in #2702, which turned
out to be incorrect usage of std::move, by removing any std::moves
introduced in that PR to be better safe than sorry. Also fixes
problems with WASM_INTERPRETER_DEBUG spotted during
debugging.

Author: dcodeIO

src/passes/Precompute.cpp

@@ -79,7 +79,7 @@ class PrecomputingExpressionRunner
     if (iter != getValues.end()) {
       auto values = iter->second;
       if (values.isConcrete()) {
-        return Flow(std::move(values));
+        return Flow(values);
       }
     }
     return ExpressionRunner<PrecomputingExpressionRunner>::visitLocalGet(curr);

src/wasm-interpreter.h

@@ -1252,7 +1252,7 @@ class ExpressionRunner : public OverriddenVisitor<SubType, Flow> {
     // Check if a constant value has been set in the context of this runner.
     auto iter = localValues.find(curr->index);
     if (iter != localValues.end()) {
-      return Flow(std::move(iter->second));
+      return Flow(iter->second);
     }
     return Flow(NONCONSTANT_FLOW);
   }
@@ -1288,7 +1288,7 @@ class ExpressionRunner : public OverriddenVisitor<SubType, Flow> {
     // Check if a constant value has been set in the context of this runner.
     auto iter = globalValues.find(curr->name);
     if (iter != globalValues.end()) {
-      return Flow(std::move(iter->second));
+      return Flow(iter->second);
     }
     return Flow(NONCONSTANT_FLOW);
   }
@@ -1327,13 +1327,13 @@ class ExpressionRunner : public OverriddenVisitor<SubType, Flow> {
             auto argFlow = visit(curr->operands[i]);
             if (!argFlow.breaking()) {
               assert(argFlow.values.isConcrete());
-              localValues[i] = std::move(argFlow.values);
+              localValues[i] = argFlow.values;
             }
           }
           auto retFlow = visit(func->body);
-          localValues = std::move(prevLocalValues);
+          localValues = prevLocalValues;
           if (retFlow.breakTo == RETURN_FLOW) {
-            return Flow(std::move(retFlow.values));
+            return Flow(retFlow.values);
           } else if (!retFlow.breaking()) {
             return retFlow;
           }
@@ -1343,7 +1343,7 @@ class ExpressionRunner : public OverriddenVisitor<SubType, Flow> {
     return Flow(NONCONSTANT_FLOW);
   }
 
-  Flow visitCallIndirect(CallIndirect*) {
+  Flow visitCallIndirect(CallIndirect* curr) {
     NOTE_ENTER("CallIndirect");
     return Flow(NONCONSTANT_FLOW);
   }
@@ -1375,39 +1375,39 @@ class ExpressionRunner : public OverriddenVisitor<SubType, Flow> {
     NOTE_ENTER("MemoryFill");
     return Flow(NONCONSTANT_FLOW);
   }
-  Flow visitAtomicRMW(AtomicRMW*) {
+  Flow visitAtomicRMW(AtomicRMW* curr) {
     NOTE_ENTER("AtomicRMW");
     return Flow(NONCONSTANT_FLOW);
   }
-  Flow visitAtomicCmpxchg(AtomicCmpxchg*) {
+  Flow visitAtomicCmpxchg(AtomicCmpxchg* curr) {
     NOTE_ENTER("AtomicCmpxchg");
     return Flow(NONCONSTANT_FLOW);
   }
-  Flow visitAtomicWait(AtomicWait*) {
+  Flow visitAtomicWait(AtomicWait* curr) {
     NOTE_ENTER("AtomicWait");
     return Flow(NONCONSTANT_FLOW);
   }
-  Flow visitAtomicNotify(AtomicNotify*) {
+  Flow visitAtomicNotify(AtomicNotify* curr) {
     NOTE_ENTER("AtomicNotify");
     return Flow(NONCONSTANT_FLOW);
   }
-  Flow visitSIMDLoad(SIMDLoad*) {
+  Flow visitSIMDLoad(SIMDLoad* curr) {
     NOTE_ENTER("SIMDLoad");
     return Flow(NONCONSTANT_FLOW);
   }
-  Flow visitSIMDLoadSplat(SIMDLoad*) {
+  Flow visitSIMDLoadSplat(SIMDLoad* curr) {
     NOTE_ENTER("SIMDLoadSplat");
     return Flow(NONCONSTANT_FLOW);
   }
-  Flow visitSIMDLoadExtend(SIMDLoad*) {
+  Flow visitSIMDLoadExtend(SIMDLoad* curr) {
     NOTE_ENTER("SIMDLoadExtend");
     return Flow(NONCONSTANT_FLOW);
   }
-  Flow visitPush(Push*) {
+  Flow visitPush(Push* curr) {
     NOTE_ENTER("Push");
     return Flow(NONCONSTANT_FLOW);
   }
-  Flow visitPop(Pop*) {
+  Flow visitPop(Pop* curr) {
     NOTE_ENTER("Pop");
     return Flow(NONCONSTANT_FLOW);
   }
@@ -2470,7 +2470,8 @@ template<typename GlobalManager, typename SubType> class ModuleInstanceBase {
       functionStack.pop_back();
     }
 #ifdef WASM_INTERPRETER_DEBUG
-    std::cout << "exiting " << function->name << " with " << ret << '\n';
+    std::cout << "exiting " << function->name << " with " << flow.values
+              << '\n';
 #endif
     return flow.values;
   }

src/wasm-printing.h

@@ -53,6 +53,10 @@ inline std::ostream& operator<<(std::ostream& o, wasm::Expression& expression) {
   return wasm::WasmPrinter::printExpression(&expression, o);
 }
 
+inline std::ostream& operator<<(std::ostream& o, wasm::Expression* expression) {
+  return wasm::WasmPrinter::printExpression(expression, o);
+}
+
 inline std::ostream& operator<<(std::ostream& o, wasm::StackInst& inst) {
   return wasm::WasmPrinter::printStackInst(&inst, o);
 }