Adds javascript overflow checking to arm64.

runtime/vm/intermediate_language_arm64.cc

Index: runtime/vm/intermediate_language_arm64.cc
===================================================================
--- runtime/vm/intermediate_language_arm64.cc	(revision 36227)
+++ runtime/vm/intermediate_language_arm64.cc	(working copy)
@@ -2448,6 +2448,20 @@
 }
 
 
+static void EmitJavascriptOverflowCheck(FlowGraphCompiler* compiler,
+                                        Range* range,
+                                        Label* overflow,
+                                        Register result) {
+  if (!range->IsWithin(-0x20000000000000LL, 0x20000000000000LL)) {
+    ASSERT(overflow != NULL);
+    __ CompareImmediate(result, -0x20000000000000LL, PP);
+    __ b(overflow, LT);
+    __ CompareImmediate(result, 0x20000000000000LL, PP);
+    __ b(overflow, GT);
+  }
+}
+
+
 static void EmitSmiShiftLeft(FlowGraphCompiler* compiler,
                              BinarySmiOpInstr* shift_left) {
   const bool is_truncating = shift_left->is_truncating();
@@ -2484,6 +2498,9 @@
       // Shift for result now we know there is no overflow.
       __ Lsl(result, left, value);
     }
+    if (FLAG_throw_on_javascript_int_overflow) {
+      EmitJavascriptOverflowCheck(compiler, shift_left->range(), deopt, result);
+    }
     return;
   }
 
@@ -2514,6 +2531,9 @@
       __ Asr(TMP, right, kSmiTagSize);  // SmiUntag right into TMP.
       __ lslv(result, left, TMP);
     }
+    if (FLAG_throw_on_javascript_int_overflow) {
+      EmitJavascriptOverflowCheck(compiler, shift_left->range(), deopt, result);
+    }
     return;
   }
 
@@ -2559,6 +2579,9 @@
     // Shift for result now we know there is no overflow.
     __ lslv(result, left, TMP);
   }
+  if (FLAG_throw_on_javascript_int_overflow) {
+    EmitJavascriptOverflowCheck(compiler, shift_left->range(), deopt, result);
+  }
 }
 
 
@@ -2733,6 +2756,9 @@
         UNREACHABLE();
         break;
     }
+    if (FLAG_throw_on_javascript_int_overflow) {
+      EmitJavascriptOverflowCheck(compiler, range(), deopt, result);
+    }
     return;
   }
 
@@ -2875,6 +2901,9 @@
       UNREACHABLE();
       break;
   }
+  if (FLAG_throw_on_javascript_int_overflow) {
+    EmitJavascriptOverflowCheck(compiler, range(), deopt, result);
+  }
 }
 
 
@@ -3562,6 +3591,9 @@
       Label* deopt = compiler->AddDeoptStub(deopt_id(), ICData::kDeoptUnaryOp);
       __ subs(result, ZR, Operand(value));
       __ b(deopt, VS);
+      if (FLAG_throw_on_javascript_int_overflow) {
+        EmitJavascriptOverflowCheck(compiler, range(), deopt, value);
+      }
       break;
     }
     case Token::kBIT_NOT:
@@ -3643,6 +3675,9 @@
   __ CompareImmediate(result, 0xC000000000000000, PP);
   __ b(&do_call, MI);
   __ SmiTag(result);
+  if (FLAG_throw_on_javascript_int_overflow) {
+    EmitJavascriptOverflowCheck(compiler, range(), &do_call, result);
+  }
   __ b(&done);
   __ Bind(&do_call);
   __ Push(value_obj);
@@ -3688,6 +3723,9 @@
   __ CompareImmediate(result, 0xC000000000000000, PP);
   __ b(deopt, MI);
   __ SmiTag(result);
+  if (FLAG_throw_on_javascript_int_overflow) {
+    EmitJavascriptOverflowCheck(compiler, range(), deopt, result);
+  }
 }
 
 
@@ -3994,7 +4032,9 @@
     __ add(TMP, result_mod, Operand(right));
     __ csel(result_mod, TMP, TMP2, GE);
     __ Bind(&done);
-
+    // FLAG_throw_on_javascript_int_overflow: not needed.
+    // Note that the result of an integer division/modulo of two
+    // in-range arguments, cannot create out-of-range result.
     return;
   }
   if (kind() == MergedMathInstr::kSinCos) {