[WebAssembly] Add except_ref as a first-class type

Summary: Add except_ref as a first-class type, according to the [[https://github.com/WebAssembly/exception-handling/blob/master/proposals/Level-1.md | Level 1 exception handling proposal ]].

Reviewers: dschuff

Subscribers: jfb, sbc100, llvm-commits

Differential Revision: https://reviews.llvm.org/D43706

llvm-svn: 326985
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
index 59bf1ad..f3ee6e7 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
@@ -127,6 +127,7 @@
     case MVT::i64:
     case MVT::f32:
     case MVT::f64:
+    case MVT::ExceptRef:
       return VT;
     case MVT::f16:
       return MVT::f32;
@@ -681,6 +682,10 @@
       Opc = WebAssembly::ARGUMENT_v4f32;
       RC = &WebAssembly::V128RegClass;
       break;
+    case MVT::ExceptRef:
+      Opc = WebAssembly::ARGUMENT_EXCEPT_REF;
+      RC = &WebAssembly::EXCEPT_REFRegClass;
+      break;
     default:
       return false;
     }
@@ -770,6 +775,11 @@
           IsDirect ? WebAssembly::CALL_v4f32 : WebAssembly::PCALL_INDIRECT_v4f32;
       ResultReg = createResultReg(&WebAssembly::V128RegClass);
       break;
+    case MVT::ExceptRef:
+      Opc = IsDirect ? WebAssembly::CALL_EXCEPT_REF
+                     : WebAssembly::PCALL_INDIRECT_EXCEPT_REF;
+      ResultReg = createResultReg(&WebAssembly::EXCEPT_REFRegClass);
+      break;
     default:
       return false;
     }
@@ -868,6 +878,10 @@
     Opc = WebAssembly::SELECT_F64;
     RC = &WebAssembly::F64RegClass;
     break;
+  case MVT::ExceptRef:
+    Opc = WebAssembly::SELECT_EXCEPT_REF;
+    RC = &WebAssembly::EXCEPT_REFRegClass;
+    break;
   default:
     return false;
   }
@@ -1274,6 +1288,9 @@
   case MVT::v4f32:
     Opc = WebAssembly::RETURN_v4f32;
     break;
+  case MVT::ExceptRef:
+    Opc = WebAssembly::RETURN_EXCEPT_REF;
+    break;
   default: return false;
   }