[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 eb6c30544516cb3953c02209bdeea2c70c9593fd..c980a87fcb40f39b131834a94784536d093bbccf 100644
--- a/src/compiler/wasm-compiler.h
+++ b/src/compiler/wasm-compiler.h
@@ -135,8 +135,10 @@ class WasmGraphBuilder {
              wasm::WasmCodePosition position = wasm::kNoCodePosition);
   Node* GrowMemory(Node* input);
   Node* Throw(Node* input);
+  Node* Catch(Node* input, wasm::WasmCodePosition position);
   unsigned InputCount(Node* node);
   bool IsPhiWithMerge(Node* phi, Node* merge);
+  bool ThrowsException(Node* node, Node** if_success, Node** if_exception);
   void AppendToMerge(Node* merge, Node* from);
   void AppendToPhi(Node* phi, Node* from);
 
@@ -153,10 +155,10 @@ class WasmGraphBuilder {
   Node* ReturnVoid();
   Node* Unreachable(wasm::WasmCodePosition position);
 
-  Node** CallDirect(uint32_t index, Node** args,
-                    wasm::WasmCodePosition position);
-  Node** CallIndirect(uint32_t index, Node** args,
-                      wasm::WasmCodePosition position);
+  Node* CallDirect(uint32_t index, Node** args, Node*** rets,
+                   wasm::WasmCodePosition position);
+  Node* CallIndirect(uint32_t index, Node** args, Node*** rets,
+                     wasm::WasmCodePosition position);
 
   void BuildJSToWasmWrapper(Handle<Code> wasm_code, wasm::FunctionSig* sig);
   void BuildWasmToJSWrapper(Handle<JSReceiver> target, wasm::FunctionSig* sig);
@@ -240,8 +242,8 @@ class WasmGraphBuilder {
   Node* MaskShiftCount64(Node* node);
 
   Node* BuildCCall(MachineSignature* sig, Node** args);
-  Node** BuildWasmCall(wasm::FunctionSig* sig, Node** args,
-                       wasm::WasmCodePosition position);
+  Node* BuildWasmCall(wasm::FunctionSig* sig, Node** args, Node*** rets,
+                      wasm::WasmCodePosition position);
 
   Node* BuildF32CopySign(Node* left, Node* right);
   Node* BuildF64CopySign(Node* left, Node* right);