Translator: Preserve locals on the stack when entering a block

Author: kateinoigakukun

FuzzTesting/FailCases/FuzzDifferential/diff-3cefb827c90b7927cc0c576d83caf9ff5bb9c9f7.wasm

@@ -1127,6 +1127,7 @@ struct InstructionTranslator<Context: TranslatorContext>: InstructionVisitor {
     mutating func visitBlock(blockType: WasmParser.BlockType) throws -> Output {
         let blockType = try module.resolveBlockType(blockType)
         let endLabel = iseqBuilder.allocLabel()
+        self.preserveLocalsOnStack(depth: self.valueStack.height)
         let stackHeight = try popPushValues(blockType.parameters)
         controlStack.pushFrame(ControlStack.ControlFrame(blockType: blockType, stackHeight: stackHeight, continuation: endLabel, kind: .block))
     }

Sources/WasmKit/Translator.swift

@@ -49,3 +49,21 @@
 )
 
 (assert_return (invoke "invalidate-relink" (i32.const 1) (i32.const 2)) (i32.const 2))
+
+(module
+  (global (mut i32) (i32.const 4))
+  (func (export "check") (result i32)
+    (local i32)
+    global.get 0
+    drop
+    local.get 0
+    block
+      i32.const 1
+      br_if 0
+      i32.const 0
+      local.set 0
+    end
+  )
+)
+
+(assert_return (invoke "check") (i32.const 0))