[wasm] Mask shift counts on architectures that don't implicitly mask.

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 423 matching lines @@
       op = m->Word32And();
       break;
     case wasm::kExprI32Ior:
       op = m->Word32Or();
       break;
     case wasm::kExprI32Xor:
       op = m->Word32Xor();
       break;
     case wasm::kExprI32Shl:
       op = m->Word32Shl();
+      right = MaskShiftCount32(right);
       break;
     case wasm::kExprI32ShrU:
       op = m->Word32Shr();
+      right = MaskShiftCount32(right);
       break;
     case wasm::kExprI32ShrS:
       op = m->Word32Sar();
+      right = MaskShiftCount32(right);
       break;
     case wasm::kExprI32Ror:
       op = m->Word32Ror();
+      right = MaskShiftCount32(right);
       break;
     case wasm::kExprI32Rol:
+      right = MaskShiftCount32(right);
       return BuildI32Rol(left, right);
     case wasm::kExprI32Eq:
       op = m->Word32Equal();
       break;
     case wasm::kExprI32Ne:
       return Invert(Binop(wasm::kExprI32Eq, left, right));
     case wasm::kExprI32LtS:
       op = m->Int32LessThan();
       break;
     case wasm::kExprI32LeS:
@@ skipping 53 matching lines @@
     case wasm::kExprI64Ior:
       op = m->Word64Or();
       break;
 // kExprI64Xor:
     case wasm::kExprI64Xor:
       op = m->Word64Xor();
       break;
 // kExprI64Shl:
     case wasm::kExprI64Shl:
       op = m->Word64Shl();
+      right = MaskShiftCount64(right);
       break;
     // kExprI64ShrU:
     case wasm::kExprI64ShrU:
       op = m->Word64Shr();
+      right = MaskShiftCount64(right);
       break;
     // kExprI64ShrS:
     case wasm::kExprI64ShrS:
       op = m->Word64Sar();
+      right = MaskShiftCount64(right);
       break;
     // kExprI64Eq:
     case wasm::kExprI64Eq:
       op = m->Word64Equal();
       break;
 // kExprI64Ne:
     case wasm::kExprI64Ne:
       return Invert(Binop(wasm::kExprI64Eq, left, right));
 // kExprI64LtS:
     case wasm::kExprI64LtS:
@@ skipping 23 matching lines @@
     case wasm::kExprI64GeU:
       op = m->Uint64LessThanOrEqual();
       std::swap(left, right);
       break;
 
 #if WASM_64
     // Opcodes only supported on 64-bit platforms.
     // TODO(titzer): query the machine operator builder here instead of #ifdef.
     case wasm::kExprI64Ror:
       op = m->Word64Ror();
+      right = MaskShiftCount64(right);
       break;
     case wasm::kExprI64Rol:
+      right = MaskShiftCount64(right);
       return BuildI64Rol(left, right);
 #endif
 
     case wasm::kExprF32CopySign:
       return BuildF32CopySign(left, right);
     case wasm::kExprF64CopySign:
       return BuildF64CopySign(left, right);
     case wasm::kExprF32Add:
       op = m->Float32Add();
       break;
@@ skipping 394 matching lines @@
 
 
 Node* WasmGraphBuilder::ReturnVoid() { return Return(0, Buffer(0)); }
 
 
 Node* WasmGraphBuilder::Unreachable() {
   trap_->Unreachable();
   return nullptr;
 }
 
+Node* WasmGraphBuilder::MaskShiftCount32(Node* node) {
+  static const int32_t kMask32 = 0x1f;
+  if (!jsgraph()->machine()->Word32ShiftIsSafe()) {
+    // Shifts by constants are so common we pattern-match them here.
+    Int32Matcher match(node);
+    if (match.HasValue()) {
+      int32_t masked = (match.Value() & kMask32);
+      if (match.Value() != masked) node = jsgraph()->Int32Constant(masked);
+    } else {
+      node = graph()->NewNode(jsgraph()->machine()->Word32And(), node,
+                              jsgraph()->Int32Constant(kMask32));
+    }
+  }
+  return node;
+}
+
+Node* WasmGraphBuilder::MaskShiftCount64(Node* node) {
+  static const int64_t kMask64 = 0x3f;
+  if (!jsgraph()->machine()->Word32ShiftIsSafe()) {
+    // Shifts by constants are so common we pattern-match them here.
+    Int64Matcher match(node);
+    if (match.HasValue()) {
+      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::BuildF32Neg(Node* input) {
   Node* result =
       Unop(wasm::kExprF32ReinterpretI32,
            Binop(wasm::kExprI32Xor, Unop(wasm::kExprI32ReinterpretF32, input),
                  jsgraph()->Int32Constant(0x80000000)));
 
   return result;
 }
 
@@ skipping 1661 matching lines @@
         static_cast<int>(function.code_end_offset - function.code_start_offset),
         decode_ms, static_cast<int>(graph.NodeCount()), compile_ms);
   }
   return code;
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8