Revert of Implement WASM big-endian support

src/compiler/wasm-compiler.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/wasm-compiler.h"
 
 #include "src/isolate-inl.h"
 
 #include "src/base/platform/elapsed-timer.h"
 #include "src/base/platform/platform.h"
@@ skipping 974 matching lines @@
       int64_t masked = (match.Value() & kMask64);
       if (match.Value() != masked) node = jsgraph()->Int64Constant(masked);
     } else {
       node = graph()->NewNode(jsgraph()->machine()->Word64And(), node,
                               jsgraph()->Int64Constant(kMask64));
     }
   }
   return node;
 }
 
-Node* WasmGraphBuilder::BuildChangeEndianness(Node* node, MachineType memtype,
-                                              wasm::LocalType wasmtype) {
-  Node* result;
-  Node* value = node;
-  const Operator* shiftLeftOpcode;
-  const Operator* shiftRightOpcode;
-  const Operator* andOpcode;
-  const Operator* orOpcode;
-  MachineOperatorBuilder* m = jsgraph()->machine();
-  int valueSizeInBytes = 1 << ElementSizeLog2Of(memtype.representation());
-  int valueSizeInBits = 8 * valueSizeInBytes;
-  bool isFloat = false;
-
-  switch (memtype.representation()) {
-    case MachineRepresentation::kFloat64:
-      value = graph()->NewNode(m->BitcastFloat64ToInt64(), node);
-      isFloat = true;
-    case MachineRepresentation::kWord64:
-      shiftLeftOpcode = m->Word64Shl();
-      shiftRightOpcode = m->Word64Shr();
-      andOpcode = m->Word64And();
-      orOpcode = m->Word64Or();
-      result = jsgraph()->Int64Constant(0);
-      break;
-    case MachineRepresentation::kFloat32:
-      value = graph()->NewNode(m->BitcastFloat32ToInt32(), node);
-      isFloat = true;
-    case MachineRepresentation::kWord32:
-    case MachineRepresentation::kWord16:
-      shiftLeftOpcode = m->Word32Shl();
-      shiftRightOpcode = m->Word32Shr();
-      andOpcode = m->Word32And();
-      orOpcode = m->Word32Or();
-      result = jsgraph()->Int32Constant(0);
-      break;
-    case MachineRepresentation::kWord8:
-      // No need to change endianness for byte size, return original node
-      return node;
-      break;
-    default:
-      UNREACHABLE();
-      break;
-  }
-
-  int i;
-  uint32_t shiftCount;
-
-  for (i = 0, shiftCount = valueSizeInBits - 8; i < valueSizeInBits / 2;
-       i += 8, shiftCount -= 16) {
-    DCHECK(shiftCount > 0);
-    DCHECK((shiftCount + 8) % 16 == 0);
-
-    Node* shiftLower = graph()->NewNode(shiftLeftOpcode, value,
-                                        jsgraph()->Int32Constant(shiftCount));
-    Node* shiftHigher = graph()->NewNode(shiftRightOpcode, value,
-                                         jsgraph()->Int32Constant(shiftCount));
-
-    Node* lowerByte;
-    Node* higherByte;
-
-    if (valueSizeInBits > 32) {
-      lowerByte = graph()->NewNode(
-          andOpcode, shiftLower,
-          jsgraph()->Int64Constant(0xFFl << (valueSizeInBits - 8 - i)));
-      higherByte = graph()->NewNode(andOpcode, shiftHigher,
-                                    jsgraph()->Int64Constant(0xFFl << i));
-    } else {
-      lowerByte = graph()->NewNode(
-          andOpcode, shiftLower,
-          jsgraph()->Int32Constant(0xFF << (valueSizeInBits - 8 - i)));
-      higherByte = graph()->NewNode(andOpcode, shiftHigher,
-                                    jsgraph()->Int32Constant(0xFF << i));
-    }
-
-    result = graph()->NewNode(orOpcode, result, lowerByte);
-    result = graph()->NewNode(orOpcode, result, higherByte);
-  }
-
-  if (isFloat) {
-    switch (memtype.representation()) {
-      case MachineRepresentation::kFloat64:
-        result = graph()->NewNode(m->BitcastInt64ToFloat64(), result);
-        break;
-      case MachineRepresentation::kFloat32:
-        result = graph()->NewNode(m->BitcastInt32ToFloat32(), result);
-        break;
-      default:
-        UNREACHABLE();
-        break;
-    }
-  }
-
-  // We need to sign extend the value
-  if (memtype.IsSigned()) {
-    DCHECK(!isFloat);
-    if (valueSizeInBits < 32) {
-      Node* shiftBitCount;
-      // Perform sign extension using following trick
-      // result = (x << machine_width - type_width) >> (machine_width -
-      // type_width)
-      if (wasmtype == wasm::kAstI64) {
-        shiftBitCount = jsgraph()->Int32Constant(64 - valueSizeInBits);
-        result = graph()->NewNode(
-            m->Word64Sar(),
-            graph()->NewNode(m->Word64Shl(), result, shiftBitCount),
-            shiftBitCount);
-      } else if (wasmtype == wasm::kAstI32) {
-        shiftBitCount = jsgraph()->Int32Constant(32 - valueSizeInBits);
-        result = graph()->NewNode(
-            m->Word32Sar(),
-            graph()->NewNode(m->Word32Shl(), result, shiftBitCount),
-            shiftBitCount);
-      }
-    }
-  }
-
-  return result;
-}
-
 Node* WasmGraphBuilder::BuildF32Neg(Node* input) {
   Node* result =
       Unop(wasm::kExprF32ReinterpretI32,
            Binop(wasm::kExprI32Xor, Unop(wasm::kExprI32ReinterpretF32, input),
                  jsgraph()->Int32Constant(0x80000000)));
 
   return result;
 }
 
 Node* WasmGraphBuilder::BuildF64Neg(Node* input) {
@@ skipping 1737 matching lines @@
                  ElementSizeLog2Of(memtype.representation());
 
   if (aligned ||
       jsgraph()->machine()->UnalignedLoadSupported(memtype, alignment)) {
     load = graph()->NewNode(jsgraph()->machine()->Load(memtype),
                             MemBuffer(offset), index, *effect_, *control_);
     *effect_ = load;
   } else {
     load = BuildUnalignedLoad(type, memtype, index, offset, alignment);
   }
-#if defined(V8_TARGET_BIG_ENDIAN)
-  // TODO(john.yan) Implement byte swap turbofan operator
-  // and use it if available for better performance
-  load = BuildChangeEndianness(load, memtype, type);
-#endif
 
   if (type == wasm::kAstI64 &&
       ElementSizeLog2Of(memtype.representation()) < 3) {
     // TODO(titzer): TF zeroes the upper bits of 64-bit loads for subword sizes.
     if (memtype.IsSigned()) {
       // sign extend
       load = graph()->NewNode(jsgraph()->machine()->ChangeInt32ToInt64(), load);
     } else {
       // zero extend
       load =
@@ skipping 100 matching lines @@
                                  uint32_t offset, uint32_t alignment, Node* val,
                                  wasm::WasmCodePosition position) {
   Node* store;
 
   // WASM semantics throw on OOB. Introduce explicit bounds check.
   BoundsCheckMem(memtype, index, offset, position);
   StoreRepresentation rep(memtype.representation(), kNoWriteBarrier);
   bool aligned = static_cast<int>(alignment) >=
                  ElementSizeLog2Of(memtype.representation());
 
-#if defined(V8_TARGET_BIG_ENDIAN)
-  // TODO(john.yan) Implement byte swap turbofan operator
-  // and use it if available for better performance
-  val = BuildChangeEndianness(val, memtype);
-#endif
-
   if (aligned ||
       jsgraph()->machine()->UnalignedStoreSupported(memtype, alignment)) {
     StoreRepresentation rep(memtype.representation(), kNoWriteBarrier);
     store =
         graph()->NewNode(jsgraph()->machine()->Store(rep), MemBuffer(offset),
                          index, val, *effect_, *control_);
     *effect_ = store;
   } else {
     store = BuildUnalignedStore(memtype, index, offset, alignment, val);
   }
@@ skipping 405 matching lines @@
                             function_->code_start_offset),
            compile_ms);
   }
 
   return code;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8