Reviewers: Yang, danno, Paul Lind, kisg,
Description:
MIPS: avoid alignment issues in FillHeapNumberWithRandom.
Copy the value using memcpy on native MIPS targets to avoid unaligned memory
access.
BUG=
TEST=cctest test-random/CrankshaftRandom
Please review this at http://codereview.chromium.org/9617011/
Affected files:
M src/v8.cc
Index: src/v8.cc
diff --git a/src/v8.cc b/src/v8.cc
index
003c75ce0b36b7567113cb0b3c1c191b3c36c24b..76546bab8874102a03fb17b536992b88e0e58e67
100644
--- a/src/v8.cc
+++ b/src/v8.cc
@@ -224,10 +224,19 @@ typedef union {
Object* V8::FillHeapNumberWithRandom(Object* heap_number,
Context* context) {
uint64_t random_bits = Random(context);
+#ifdef V8_HOST_ARCH_MIPS
+ // Copy the value to a local variable to avoid alignment issues.
+ double_int_union num;
+ double_int_union* r = #
+ memcpy(r, heap_number + HeapNumber::kValueOffset - kHeapObjectTag,
+ sizeof(num));
+#else
// Make a double* from address (heap_number + sizeof(double)).
double_int_union* r = reinterpret_cast<double_int_union*>(
reinterpret_cast<char*>(heap_number) +
HeapNumber::kValueOffset - kHeapObjectTag);
+#endif
+
// Convert 32 random bits to 0.(32 random bits) in a double
// by computing:
// ( 1.(20 0s)(32 random bits) x 2^20 ) - (1.0 x 2^20)).
@@ -236,6 +245,11 @@ Object* V8::FillHeapNumberWithRandom(Object*
heap_number,
r->uint64_t_value |= random_bits;
r->double_value -= binary_million;
+#ifdef V8_HOST_ARCH_MIPS
+ memcpy(heap_number + HeapNumber::kValueOffset - kHeapObjectTag, r,
+ sizeof(num));
+#endif
+
return heap_number;
}
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