[WebAssembly] Switch to MC for instruction printing.

This encompasses several changes which are all interconnected:
 - Use the MC framework for printing almost all instructions.
 - AsmStrings are now live.
 - This introduces an indirection between LLVM vregs and WebAssembly registers,
   and a new pass, WebAssemblyRegNumbering, for computing a basic the mapping.
   This addresses some basic issues with argument registers and unused registers.
 - The way ARGUMENT instructions are handled no longer generates redundant
   get_local+set_local for every argument.

This also changes the assembly syntax somewhat; most notably, MC's printing
use sigils on label names, so those are no longer present, and push/pop now
have a sigil to keep them unambiguous.

The usage of set_local/get_local/$push/$pop will continue to evolve
significantly. This patch is just one step of a larger change.

llvm-svn: 252858

1 files changed, 4 insertions, 2 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrControl.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrControl.td
index 6aae5d38d0b..acfd738a8fa 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrControl.td
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrControl.td
@@ -41,9 +41,11 @@ def BR   : I<(outs), (ins bb_op:$dst),
 // currently.
 let isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 in {
 def SWITCH_I32 : I<(outs), (ins I32:$index, variable_ops),
-                   [(WebAssemblyswitch I32:$index)]>;
+                   [(WebAssemblyswitch I32:$index)],
+                   "switch $index">;
 def SWITCH_I64 : I<(outs), (ins I64:$index, variable_ops),
-                   [(WebAssemblyswitch I64:$index)]>;
+                   [(WebAssemblyswitch I64:$index)],
+                   "switch $index">;
 } // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1
 
 // Placemarkers to indicate the start of a block or loop scope.