all: use internal/cpu feature variables directly

Avoid using package specific variables when there is a one to one
correspondance to cpu feature support exported by internal/cpu.

This makes it clearer which cpu feature is referenced.
Another advantage is that internal/cpu variables are padded to avoid
false sharing and memory and cache usage is shared by multiple packages.

Change-Id: If18fb448a95207cfa6a3376f3b2ddc4b230dd138
Reviewed-on: https://go-review.googlesource.com/126596
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

1 files changed, 6 insertions, 8 deletions

diff --git a/src/hash/crc32/crc32_arm64.go b/src/hash/crc32/crc32_arm64.go
index 1f8779d506..0242d1d8a7 100644
--- a/src/hash/crc32/crc32_arm64.go
+++ b/src/hash/crc32/crc32_arm64.go
@@ -13,20 +13,18 @@ import "internal/cpu"
 func castagnoliUpdate(crc uint32, p []byte) uint32
 func ieeeUpdate(crc uint32, p []byte) uint32
 
-var hasCRC32 = cpu.ARM64.HasCRC32
-
 func archAvailableCastagnoli() bool {
-	return hasCRC32
+	return cpu.ARM64.HasCRC32
 }
 
 func archInitCastagnoli() {
-	if !hasCRC32 {
+	if !cpu.ARM64.HasCRC32 {
 		panic("arch-specific crc32 instruction for Catagnoli not available")
 	}
 }
 
 func archUpdateCastagnoli(crc uint32, p []byte) uint32 {
-	if !hasCRC32 {
+	if !cpu.ARM64.HasCRC32 {
 		panic("arch-specific crc32 instruction for Castagnoli not available")
 	}
 
@@ -34,17 +32,17 @@ func archUpdateCastagnoli(crc uint32, p []byte) uint32 {
 }
 
 func archAvailableIEEE() bool {
-	return hasCRC32
+	return cpu.ARM64.HasCRC32
 }
 
 func archInitIEEE() {
-	if !hasCRC32 {
+	if !cpu.ARM64.HasCRC32 {
 		panic("arch-specific crc32 instruction for IEEE not available")
 	}
 }
 
 func archUpdateIEEE(crc uint32, p []byte) uint32 {
-	if !hasCRC32 {
+	if !cpu.ARM64.HasCRC32 {
 		panic("arch-specific crc32 instruction for IEEE not available")
 	}