cmd/dist: use purego tag when building the bootstrap binaries

This is in addition to the current math_big_pure_go tag.
Using purego ensures that we can build the cmd binaries with gccgo.

For #53662

Change-Id: Ib82f8bf10659b5f94935f2b427ae8b2da875cd3b
Reviewed-on: https://go-review.googlesource.com/c/go/+/415934
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>

diff --git a/src/cmd/dist/buildtool.go b/src/cmd/dist/buildtool.go
index 947da115e3bd03b91edd096c54554f9fdfb17c04..400c2e85b6799d4d46562117cf16b891a4d696a0 100644 (file)
--- a/src/cmd/dist/buildtool.go
+++ b/src/cmd/dist/buildtool.go
@@ -204,6 +204,8 @@ func bootstrapBuildTools() {
        // https://groups.google.com/d/msg/golang-dev/Ss7mCKsvk8w/Gsq7VYI0AwAJ
        // Use the math_big_pure_go build tag to disable the assembly in math/big
        // which may contain unsupported instructions.
+       // Use the purego build tag to disable other assembly code,
+       // such as in cmd/internal/notsha256.
        // Note that if we are using Go 1.10 or later as bootstrap, the -gcflags=-l
        // only applies to the final cmd/go binary, but that's OK: if this is Go 1.10
        // or later we don't need to disable inlining to work around bugs in the Go 1.4 compiler.
@@ -211,7 +213,7 @@ func bootstrapBuildTools() {
                pathf("%s/bin/go", goroot_bootstrap),
                "install",
                "-gcflags=-l",
-               "-tags=math_big_pure_go compiler_bootstrap",
+               "-tags=math_big_pure_go compiler_bootstrap purego",
        }
        if vflag > 0 {
                cmd = append(cmd, "-v")