cmd/go: GOMIPS environment variable does not affect caching of mipsle code

[ianlancetaylor]

This script shows that the results of compiling with GOARCH=mipsle are cached without regard to the value of the GOMIPS environment variable.

> cat foo.go
package p

func F(f float64) float64 {
	return f + f
}
> go clean -cache
> GOARCH=mipsle go build -gcflags=-S foo.go 2>&1 | grep F0
	0x0000 00000 (/home/iant/foo10.go:4)	MOVF	"".f(FP), F0
	0x0008 00008 (/home/iant/foo10.go:4)	ADDD	F0, F0, F0
	0x000c 00012 (/home/iant/foo10.go:4)	MOVF	F0, "".~r1+8(FP)
> GOARCH=mipsle GOMIPS=softfloat go build -gcflags=-S foo.go 2>&1 | grep F0
	0x0000 00000 (/home/iant/foo10.go:4)	MOVF	"".f(FP), F0
	0x0008 00008 (/home/iant/foo10.go:4)	ADDD	F0, F0, F0
	0x000c 00012 (/home/iant/foo10.go:4)	MOVF	F0, "".~r1+8(FP)
> go clean -cache
> GOARCH=mipsle GOMIPS=softfloat go build -gcflags=-S foo.go 2>&1 | grep F0
>

[gopherbot]

Change https://golang.org/cl/131378 mentions this issue: cmd/go/internal/work: fix missing GOMIPS{,64} to ActionID on little endian

[gopherbot]

Change https://golang.org/cl/131379 mentions this issue: cmd/go: add GOMIPS value to build id for mipsle

[FiloSottile]

@gopherbot please file this issue for backport to 1.11 and 1.10 (GOMIPS and the cache were introduced in 1.10, so it might affect both, if not please close the 1.10 issue).

@ianlancetaylor had milestoned this for 1.11.1 and I don't see a cherry-pick, but it was closed by the master fix.

[gopherbot]

Backport issue(s) opened: #27420 (for 1.11), #27421 (for 1.10).

Remember to create the cherry-pick CL(s) as soon as the patch is submitted to master, according to https://golang.org/wiki/MinorReleases.

[gopherbot]

Change https://golang.org/cl/138176 mentions this issue: [release-branch.go1.11] cmd/go: add GOMIPS value to build id for mipsle