[WebAssembly] Added default stack-only instruction mode for MC.

Summary:
Made it convert from register to stack based instructions, and removed the registers.
Fixes to related code that was expecting register based instructions.
Added the correct testing flag to all tests, depending on what the
format they were expecting so far.
Translated one test to stack format as example: reg-stackify-stack.ll

tested:
llvm-lit -v `find test -name WebAssembly`
unittests/MC/*

Reviewers: dschuff, sunfish

Subscribers: sbc100, jgravelle-google, eraman, aheejin, llvm-commits, jfb

Differential Revision: https://reviews.llvm.org/D51241

llvm-svn: 340750

1 files changed, 5 insertions, 2 deletions

diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
index bff074d987c..3f24f93fe92 100644
--- a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
+++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
@@ -72,8 +72,11 @@ void WebAssemblyMCCodeEmitter::encodeInstruction(
   }
 
   // For br_table instructions, encode the size of the table. In the MCInst,
-  // there's an index operand, one operand for each table entry, and the
-  // default operand.
+  // there's an index operand (if not a stack instruction), one operand for
+  // each table entry, and the default operand.
+  if (MI.getOpcode() == WebAssembly::BR_TABLE_I32_S ||
+      MI.getOpcode() == WebAssembly::BR_TABLE_I64_S)
+    encodeULEB128(MI.getNumOperands() - 1, OS);
   if (MI.getOpcode() == WebAssembly::BR_TABLE_I32 ||
       MI.getOpcode() == WebAssembly::BR_TABLE_I64)
     encodeULEB128(MI.getNumOperands() - 2, OS);