[WebAssembly] Emit .param, .result, and .local through MC.

This eliminates one of the main remaining uses of EmitRawText.

llvm-svn: 253878
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td
index dae9cff..1fa7902 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td
@@ -124,6 +124,11 @@
                    [(set I32:$dst, (WebAssemblywrapper tjumptable:$addr))],
                    "jump_table\t$dst, $addr">;
 
+// Function signature and local variable declaration "instructions".
+def PARAM  : I<(outs), (ins variable_ops), [], ".param  \t">;
+def RESULT : I<(outs), (ins variable_ops), [], ".result \t">;
+def LOCAL  : I<(outs), (ins variable_ops), [], ".local  \t">;
+
 //===----------------------------------------------------------------------===//
 // Additional sets of instructions.
 //===----------------------------------------------------------------------===//