[WebAssembly] v128.const

Summary:
This CL implements v128.const for each vector type. New operand types
are added to ensure the vector contents can be serialized without LEB
encoding. Tests are added for instruction selection, encoding,
assembly and disassembly.

Reviewers: aheejin, dschuff, aardappel

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D50873

llvm-svn: 340336

2 files changed, 32 insertions, 7 deletions

diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
index 417912604e0..bff074d987c 100644
--- a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
+++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
@@ -90,17 +90,34 @@ void WebAssemblyMCCodeEmitter::encodeInstruction(
         const MCOperandInfo &Info = Desc.OpInfo[i];
         LLVM_DEBUG(dbgs() << "Encoding immediate: type="
                           << int(Info.OperandType) << "\n");
-        if (Info.OperandType == WebAssembly::OPERAND_I32IMM) {
+        switch (Info.OperandType) {
+        case WebAssembly::OPERAND_I32IMM:
           encodeSLEB128(int32_t(MO.getImm()), OS);
-        } else if (Info.OperandType == WebAssembly::OPERAND_OFFSET32) {
+          break;
+        case WebAssembly::OPERAND_OFFSET32:
           encodeULEB128(uint32_t(MO.getImm()), OS);
-        } else if (Info.OperandType == WebAssembly::OPERAND_I64IMM) {
+          break;
+        case WebAssembly::OPERAND_I64IMM:
           encodeSLEB128(int64_t(MO.getImm()), OS);
-        } else if (Info.OperandType == WebAssembly::OPERAND_GLOBAL) {
-          llvm_unreachable("wasm globals should only be accessed symbolicly");
-        } else if (Info.OperandType == WebAssembly::OPERAND_SIGNATURE) {
+          break;
+        case WebAssembly::OPERAND_SIGNATURE:
           OS << uint8_t(MO.getImm());
-        } else {
+          break;
+        case WebAssembly::OPERAND_VEC_I8IMM:
+          support::endian::write<uint8_t>(OS, MO.getImm(), support::little);
+          break;
+        case WebAssembly::OPERAND_VEC_I16IMM:
+          support::endian::write<uint16_t>(OS, MO.getImm(), support::little);
+          break;
+        case WebAssembly::OPERAND_VEC_I32IMM:
+          support::endian::write<uint32_t>(OS, MO.getImm(), support::little);
+          break;
+        case WebAssembly::OPERAND_VEC_I64IMM:
+          support::endian::write<uint64_t>(OS, MO.getImm(), support::little);
+          break;
+        case WebAssembly::OPERAND_GLOBAL:
+          llvm_unreachable("wasm globals should only be accessed symbolicly");
+        default:
           encodeULEB128(uint64_t(MO.getImm()), OS);
         }
       } else {
diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h
index b4639b4afdc..4ca921481dc 100644
--- a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h
+++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h
@@ -59,6 +59,14 @@ enum OperandType {
   OPERAND_F32IMM,
   /// 64-bit floating-point immediates.
   OPERAND_F64IMM,
+  /// 8-bit vector lane immediate
+  OPERAND_VEC_I8IMM,
+  /// 16-bit vector lane immediate
+  OPERAND_VEC_I16IMM,
+  /// 32-bit vector lane immediate
+  OPERAND_VEC_I32IMM,
+  /// 64-bit vector lane immediate
+  OPERAND_VEC_I64IMM,
   /// 32-bit unsigned function indices.
   OPERAND_FUNCTION32,
   /// 32-bit unsigned memory offsets.