time: change nsec back to int32

The garbage collector and stack scans are good enough now.

Fixes #7446.

LGTM=r
R=r, dvyukov
CC=golang-codereviews, mdempsky, mtj
https://golang.org/cl/112870046

diff --git a/src/pkg/time/time.go b/src/pkg/time/time.go
index fa449c052d9b9ff98b955b41d7fe6af771b7ed31..4f76d79ee59a3ff60b730e8fcf0ba8c0974c2000 100644 (file)
--- a/src/pkg/time/time.go
+++ b/src/pkg/time/time.go
@@ -39,14 +39,7 @@ type Time struct {
        // nsec specifies a non-negative nanosecond
        // offset within the second named by Seconds.
        // It must be in the range [0, 999999999].
-       //
-       // It is declared as uintptr instead of int32 or uint32
-       // to avoid garbage collector aliasing in the case where
-       // on a 64-bit system the int32 or uint32 field is written
-       // over the low half of a pointer, creating another pointer.
-       // TODO(rsc): When the garbage collector is completely
-       // precise, change back to int32.
-       nsec uintptr
+       nsec int32
 
        // loc specifies the Location that should be used to
        // determine the minute, hour, month, day, and year
@@ -619,7 +612,7 @@ func (t Time) Add(d Duration) Time {
                t.sec--
                nsec += 1e9
        }
-       t.nsec = uintptr(nsec)
+       t.nsec = nsec
        return t
 }
 
@@ -782,7 +775,7 @@ func now() (sec int64, nsec int32)
 // Now returns the current local time.
 func Now() Time {
        sec, nsec := now()
-       return Time{sec + unixToInternal, uintptr(nsec), Local}
+       return Time{sec + unixToInternal, nsec, Local}
 }
 
 // UTC returns t with the location set to UTC.
@@ -899,7 +892,7 @@ func (t *Time) UnmarshalBinary(data []byte) error {
                int64(buf[3])<<32 | int64(buf[2])<<40 | int64(buf[1])<<48 | int64(buf[0])<<56
 
        buf = buf[8:]
-       t.nsec = uintptr(int32(buf[3]) | int32(buf[2])<<8 | int32(buf[1])<<16 | int32(buf[0])<<24)
+       t.nsec = int32(buf[3]) | int32(buf[2])<<8 | int32(buf[1])<<16 | int32(buf[0])<<24
 
        buf = buf[4:]
        offset := int(int16(buf[1])|int16(buf[0])<<8) * 60
@@ -978,7 +971,7 @@ func Unix(sec int64, nsec int64) Time {
                        sec--
                }
        }
-       return Time{sec + unixToInternal, uintptr(nsec), Local}
+       return Time{sec + unixToInternal, int32(nsec), Local}
 }
 
 func isLeap(year int) bool {
@@ -1087,7 +1080,7 @@ func Date(year int, month Month, day, hour, min, sec, nsec int, loc *Location) T
                unix -= int64(offset)
        }
 
-       return Time{unix + unixToInternal, uintptr(nsec), loc}
+       return Time{unix + unixToInternal, int32(nsec), loc}
 }
 
 // Truncate returns the result of rounding t down to a multiple of d (since the zero time).