cmd/link: don't pass all linker args when testing flag

Some linker flags can actually be input files, which can cause
misleading errors when doing the trial link, which can cause the
linker to incorrectly decide that the flag is not supported, which can
cause the link to fail.

Fixes #27510
Updates #27110
Updates #27293

Change-Id: I70c1e913cee3c813e7b267bf779bcff26d4d194a
Reviewed-on: https://go-review.googlesource.com/134057
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Damien Neil <dneil@google.com>

diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
index 60124e32128cff40e809c21d36fcef3cbd8a16d7..7029ba19c63eaaecd6fae4d42d2fb08f91df757b 100644 (file)
--- a/src/cmd/link/internal/ld/lib.go
+++ b/src/cmd/link/internal/ld/lib.go
@@ -1379,9 +1379,58 @@ func linkerFlagSupported(linker, flag string) bool {
                }
        })
 
+       flagsWithNextArgSkip := []string{
+               "-F",
+               "-l",
+               "-L",
+               "-framework",
+               "-Wl,-framework",
+               "-Wl,-rpath",
+               "-Wl,-undefined",
+       }
+       flagsWithNextArgKeep := []string{
+               "-arch",
+               "-isysroot",
+               "--sysroot",
+               "-target",
+       }
+       prefixesToKeep := []string{
+               "-f",
+               "-m",
+               "-p",
+               "-Wl,",
+               "-arch",
+               "-isysroot",
+               "--sysroot",
+               "-target",
+       }
+
        var flags []string
-       flags = append(flags, ldflag...)
-       flags = append(flags, strings.Fields(*flagExtldflags)...)
+       keep := false
+       skip := false
+       extldflags := strings.Fields(*flagExtldflags)
+       for _, f := range append(extldflags, ldflag...) {
+               if keep {
+                       flags = append(flags, f)
+                       keep = false
+               } else if skip {
+                       skip = false
+               } else if f == "" || f[0] != '-' {
+               } else if contains(flagsWithNextArgSkip, f) {
+                       skip = true
+               } else if contains(flagsWithNextArgKeep, f) {
+                       flags = append(flags, f)
+                       keep = true
+               } else {
+                       for _, p := range prefixesToKeep {
+                               if strings.HasPrefix(f, p) {
+                                       flags = append(flags, f)
+                                       break
+                               }
+                       }
+               }
+       }
+
        flags = append(flags, flag, "trivial.c")
 
        cmd := exec.Command(linker, flags...)

diff --git a/src/cmd/link/internal/ld/util.go b/src/cmd/link/internal/ld/util.go
index b80e6106ba03e0665f324c4cfae64e6f83a3f38f..b5b02296a14d2750b51affb6e779dbc3ed7d36b1 100644 (file)
--- a/src/cmd/link/internal/ld/util.go
+++ b/src/cmd/link/internal/ld/util.go
@@ -89,3 +89,13 @@ var start = time.Now()
 func elapsed() float64 {
        return time.Since(start).Seconds()
 }
+
+// contains reports whether v is in s.
+func contains(s []string, v string) bool {
+       for _, x := range s {
+               if x == v {
+                       return true
+               }
+       }
+       return false
+}