Option to truncate integers to 64 bits, part 1 (core VM changes)

runtime/vm/intermediate_language.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef RUNTIME_VM_INTERMEDIATE_LANGUAGE_H_
 #define RUNTIME_VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
+#include "vm/flags.h"
 #include "vm/growable_array.h"
 #include "vm/locations.h"
 #include "vm/method_recognizer.h"
 #include "vm/object.h"
 #include "vm/parser.h"
 #include "vm/token_position.h"
 
 namespace dart {
 
 class BitVector;
@@ skipping 703 matching lines @@
 
   // Call instructions override this function and return the number of
   // pushed arguments.
   virtual intptr_t ArgumentCount() const { return 0; }
   virtual PushArgumentInstr* PushArgumentAt(intptr_t index) const {
     UNREACHABLE();
     return NULL;
   }
   inline Definition* ArgumentAt(intptr_t index) const;
 
-  // Returns true, if this instruction can deoptimize with its current imputs.
+  // Returns true, if this instruction can deoptimize with its current inputs.
   // This property can change if we add or remove redefinitions that constrain
   // the type or the range of input operands during compilation.
   virtual bool ComputeCanDeoptimize() const = 0;
 
   // Once we removed the deopt environment, we assume that this
   // instruction can't deoptimize.
   bool CanDeoptimize() const { return env() != NULL && ComputeCanDeoptimize(); }
 
   // Visiting support.
   virtual void Accept(FlowGraphVisitor* visitor) = 0;
@@ skipping 6428 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(ShiftUint32OpInstr);
 };
 
 
 class BinaryMintOpInstr : public BinaryIntegerOpInstr {
  public:
   BinaryMintOpInstr(Token::Kind op_kind,
                     Value* left,
                     Value* right,
                     intptr_t deopt_id)
-      : BinaryIntegerOpInstr(op_kind, left, right, deopt_id) {}
+      : BinaryIntegerOpInstr(op_kind, left, right, deopt_id) {
+    if (FLAG_limit_ints_to_64_bits) {
+      mark_truncating();
+    }
+  }
 
   virtual bool ComputeCanDeoptimize() const {
-    return (can_overflow() &&
-            ((op_kind() == Token::kADD) || (op_kind() == Token::kSUB))) ||
-           (op_kind() == Token::kMUL);  // Deopt if inputs are not int32.
+    switch (op_kind()) {
+      case Token::kADD:
+      case Token::kSUB:
+        return can_overflow();
+      case Token::kMUL:
+// Note that ARM64 does not support operations with unboxed mints,
+// so it is not handled here.
+#if defined(TARGET_ARCH_X64)
+        return can_overflow();  // Deopt if overflow.
+#else
+        // IA32, ARM
+        return true;  // Deopt if inputs are not int32.
+#endif
+      default:
+        return false;
+    }
   }
 
   virtual Representation representation() const { return kUnboxedMint; }
 
   virtual Representation RequiredInputRepresentation(intptr_t idx) const {
     ASSERT((idx == 0) || (idx == 1));
     return kUnboxedMint;
   }
 
   virtual void InferRange(RangeAnalysis* analysis, Range* range);
   virtual CompileType ComputeType() const;
 
   DECLARE_INSTRUCTION(BinaryMintOp)
 
  private:
   DISALLOW_COPY_AND_ASSIGN(BinaryMintOpInstr);
 };
 
 
 class ShiftMintOpInstr : public BinaryIntegerOpInstr {
  public:
   ShiftMintOpInstr(Token::Kind op_kind,
                    Value* left,
                    Value* right,
                    intptr_t deopt_id)
       : BinaryIntegerOpInstr(op_kind, left, right, deopt_id),
         shift_range_(NULL) {
     ASSERT((op_kind == Token::kSHR) || (op_kind == Token::kSHL));
+    if (FLAG_limit_ints_to_64_bits) {
+      mark_truncating();
+    }
   }
 
   Range* shift_range() const { return shift_range_; }
 
   virtual bool ComputeCanDeoptimize() const {
     return has_shift_count_check() ||
            (can_overflow() && (op_kind() == Token::kSHL));
   }
 
   virtual Representation representation() const { return kUnboxedMint; }
@@ skipping 1030 matching lines @@
   LocationSummary* Name::MakeLocationSummary(Zone* zone, bool opt) const {     \
     UNIMPLEMENTED();                                                           \
     return NULL;                                                               \
   }                                                                            \
   void Name::EmitNativeCode(FlowGraphCompiler* compiler) { UNIMPLEMENTED(); }
 
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_INTERMEDIATE_LANGUAGE_H_