[WASM] Implements catch for the wasm low level exception mechanism.

src/compiler/wasm-compiler.h

Index: src/compiler/wasm-compiler.h
diff --git a/src/compiler/wasm-compiler.h b/src/compiler/wasm-compiler.h
index e4599363630f6b32dc18955f6f8b3ab32cbdc0fe..5c9494390b9e2954ff481d7040f759696d8725da 100644
--- a/src/compiler/wasm-compiler.h
+++ b/src/compiler/wasm-compiler.h
@@ -135,8 +135,12 @@ class WasmGraphBuilder {
              wasm::WasmCodePosition position = wasm::kNoCodePosition);
   Node* GrowMemory(Node* input);
   Node* Throw(Node* input);
+  Node* Catch(Node* input, wasm::WasmCodePosition position);
+  Node* IfSuccess(Node* input);
+  Node* IfException(Node* input);
   unsigned InputCount(Node* node);
   bool IsPhiWithMerge(Node* phi, Node* merge);
+  bool DoesNotThrow(Node* node);
   void AppendToMerge(Node* merge, Node* from);
   void AppendToPhi(Node* phi, Node* from);