1 files changed, 91 insertions, 0 deletions
diff --git a/src/wasm-validator.h b/src/wasm-validator.h
new file mode 100644
index 000000000..49e7a6a33
--- /dev/null
+++ b/src/wasm-validator.h
@@ -0,0 +1,91 @@
+
+//
+// Simple WebAssembly module validator.
+//
+
+#include "wasm.h"
+
+namespace wasm {
+
+struct WasmValidator : public WasmWalker {
+  bool valid;
+
+public:
+  bool validate(Module& module) {
+    valid = true;
+    startWalk(&module);
+    return valid;
+  }
+
+  // visitors
+
+  void visitSetLocal(SetLocal *curr) override {
+    shouldBeTrue(curr->type == curr->value->type);
+  }
+  void visitLoad(Load *curr) override {
+    validateAlignment(curr->align);
+  }
+  void visitStore(Store *curr) override {
+    validateAlignment(curr->align);
+  }
+  void visitSwitch(Switch *curr) override {
+    std::set<Name> inTable;
+    for (auto target : curr->targets) {
+      if (target.is()) {
+        inTable.insert(target);
+      }
+    }
+    for (auto& c : curr->cases) {
+      shouldBeFalse(c.name.is() && inTable.find(c.name) == inTable.end());
+    }
+    shouldBeFalse(curr->default_.is() && inTable.find(curr->default_) == inTable.end());
+  }
+  void visitMemory(Memory *curr) override {
+    shouldBeFalse(curr->initial > curr->max);
+    size_t top = 0;
+    for (auto segment : curr->segments) {
+      shouldBeFalse(segment.offset < top);
+      top = segment.offset + segment.size;
+    }
+    shouldBeFalse(top > curr->initial);
+  }
+  void visitModule(Module *curr) override {
+    for (auto& exp : curr->exports) {
+      Name name = exp->name;
+      bool found = false;
+      for (auto& func : curr->functions) {
+        if (func->name == name) {
+          found = true;
+          break;
+        }
+      }
+      shouldBeTrue(found);
+    }
+  }
+
+private:
+  // helpers
+
+  void shouldBeTrue(bool result) {
+    if (!result) valid = false;
+  }
+  void shouldBeFalse(bool result) {
+    if (result) valid = false;
+  }
+
+  void validateAlignment(size_t align) {
+    switch (align) {
+      case 1:
+      case 2:
+      case 4:
+      case 8: break;
+      default:{
+        valid = false;
+        break;
+      }
+    }
+  }
+};
+
+} // namespace wasm
+