[dev.link] all: merge branch 'master' into dev.link

[gostls13.git] / src / cmd / compile / internal / gc / main.go

diff --git a/src/cmd/compile/internal/gc/main.go b/src/cmd/compile/internal/gc/main.go
index 27ed4ee3ccea2cf540b7e99328d47cac1fbec0d0..d04c09c93e66cc323b85ead23115a006d0da3f8b 100644 (file)
--- a/src/cmd/compile/internal/gc/main.go
+++ b/src/cmd/compile/internal/gc/main.go
@@ -36,7 +36,9 @@ import (
 var imported_unsafe bool
 
 var (
-       buildid string
+       buildid      string
+       spectre      string
+       spectreIndex bool
 )
 
 var (
@@ -250,6 +252,7 @@ func Main(archInit func(*Arch)) {
        if sys.RaceDetectorSupported(objabi.GOOS, objabi.GOARCH) {
                flag.BoolVar(&flag_race, "race", false, "enable race detector")
        }
+       flag.StringVar(&spectre, "spectre", spectre, "enable spectre mitigations in `list` (all, index, ret)")
        if enableTrace {
                flag.BoolVar(&trace, "t", false, "trace type-checking")
        }
@@ -282,10 +285,36 @@ func Main(archInit func(*Arch)) {
 
        objabi.Flagparse(usage)
 
+       for _, f := range strings.Split(spectre, ",") {
+               f = strings.TrimSpace(f)
+               switch f {
+               default:
+                       log.Fatalf("unknown setting -spectre=%s", f)
+               case "":
+                       // nothing
+               case "all":
+                       spectreIndex = true
+                       Ctxt.Retpoline = true
+               case "index":
+                       spectreIndex = true
+               case "ret":
+                       Ctxt.Retpoline = true
+               }
+       }
+
+       if spectreIndex {
+               switch objabi.GOARCH {
+               case "amd64":
+                       // ok
+               default:
+                       log.Fatalf("GOARCH=%s does not support -spectre=index", objabi.GOARCH)
+               }
+       }
+
        // Record flags that affect the build result. (And don't
        // record flags that don't, since that would cause spurious
        // changes in the binary.)
-       recordFlags("B", "N", "l", "msan", "race", "shared", "dynlink", "dwarflocationlists", "dwarfbasentries", "smallframes", "go115newobj")
+       recordFlags("B", "N", "l", "msan", "race", "shared", "dynlink", "dwarflocationlists", "dwarfbasentries", "smallframes", "spectre", "go115newobj")
 
        if smallFrames {
                maxStackVarSize = 128 * 1024