[dev.boringcrypto] cmd: use notsha256 instead of md5, sha1, sha256

When we add GOEXPERIMENT=boringcrypto, the bootstrap process
will not converge if the compiler itself depends on the boringcrypto
cgo-based implementations of sha1 and sha256.

Using notsha256 avoids boringcrypto and makes bootstrap converge.
Removing md5 is not strictly necessary but it seemed worthwhile to
be consistent.

For #51940.

Change-Id: Iba649507e0964d1a49a1d16e463dd23c4e348f14
Reviewed-on: https://go-review.googlesource.com/c/go/+/402595
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/cmd/cgo/main.go b/src/cmd/cgo/main.go
index 364d8b81fb..75d48c2ede 100644
--- a/src/cmd/cgo/main.go
+++ b/src/cmd/cgo/main.go
@@ -11,7 +11,6 @@
 package main
 
 import (
-	"crypto/md5"
 	"flag"
 	"fmt"
 	"go/ast"
@@ -28,6 +27,7 @@ import (
 	"strings"
 
 	"cmd/internal/edit"
+	"cmd/internal/notsha256"
 	"cmd/internal/objabi"
 )
 
@@ -329,8 +329,8 @@ func main() {
 	// we use to coordinate between gcc and ourselves.
 	// We already put _cgo_ at the beginning, so the main
 	// concern is other cgo wrappers for the same functions.
-	// Use the beginning of the md5 of the input to disambiguate.
-	h := md5.New()
+	// Use the beginning of the notsha256 of the input to disambiguate.
+	h := notsha256.New()
 	io.WriteString(h, *importPath)
 	fs := make([]*File, len(goFiles))
 	for i, input := range goFiles {