[WebAssembly] Implementation of intrinsic for ref.null and HeapType removal

This patch implements the intrinsic for ref.null.
In the process of implementing int_wasm_ref_null_func() and
int_wasm_ref_null_extern() intrinsics, it removes the redundant
HeapType.

This also causes the textual assembler syntax for ref.null to
change. Instead of receiving an argument: `func` or `extern`, the
instruction mnemonic is either ref.null_func or ref.null_extern,
without the need for a further operand.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D114979

1 files changed, 0 insertions, 22 deletions

diff --git a/llvm/lib/Target/WebAssembly/Disassembler/WebAssemblyDisassembler.cpp b/llvm/lib/Target/WebAssembly/Disassembler/WebAssemblyDisassembler.cpp
index 2e1e4f0..5d38145 100644
--- a/llvm/lib/Target/WebAssembly/Disassembler/WebAssemblyDisassembler.cpp
+++ b/llvm/lib/Target/WebAssembly/Disassembler/WebAssemblyDisassembler.cpp
@@ -241,28 +241,6 @@ MCDisassembler::DecodeStatus WebAssemblyDisassembler::getInstruction(
       }
       break;
     }
-    // heap_type operands, for e.g. ref.null:
-    case WebAssembly::OPERAND_HEAPTYPE: {
-      int64_t Val;
-      uint64_t PrevSize = Size;
-      if (!nextLEB(Val, Bytes, Size, true))
-        return MCDisassembler::Fail;
-      if (Val < 0 && Size == PrevSize + 1) {
-        // The HeapType encoding is like BlockType, in that encodings that
-        // decode as negative values indicate ValTypes.  In practice we expect
-        // either wasm::ValType::EXTERNREF or wasm::ValType::FUNCREF here.
-        //
-        // The positive SLEB values are reserved for future expansion and are
-        // expected to be type indices in the typed function references
-        // proposal, and should disassemble as MCSymbolRefExpr as in BlockType
-        // above.
-        MI.addOperand(MCOperand::createImm(Val & 0x7f));
-      } else {
-        MI.addOperand(
-            MCOperand::createImm(int64_t(WebAssembly::HeapType::Invalid)));
-      }
-      break;
-    }
     // FP operands.
     case WebAssembly::OPERAND_F32IMM: {
       if (!parseImmediate<float>(MI, Size, Bytes))