cmd/link: fix outdated output mmap check

Outbuf.View used to perform a mmap check by default
and return an error if the check failed,
this behavior has been changed so that now
the View never returns any error,
so the usage needs to be modified accordingly.

Change-Id: I76ffcda5476847f6fed59856a5a5161734f47562
GitHub-Last-Rev: 6449f2973d28c3b4a5c9e289c38dfcc38f83b3d9
GitHub-Pull-Request: golang/go#73730
Reviewed-on: https://go-review.googlesource.com/c/go/+/673095
Reviewed-by: Keith Randall <khr@golang.org>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

3 files changed, 10 insertions, 13 deletions

diff --git a/src/cmd/link/internal/ld/asmb.go b/src/cmd/link/internal/ld/asmb.go
index ca9a57741c..2088e13be1 100644
--- a/src/cmd/link/internal/ld/asmb.go
+++ b/src/cmd/link/internal/ld/asmb.go
@@ -195,10 +195,7 @@ func relocSectFn(ctxt *Link, relocSect func(*Link, *OutBuf, *sym.Section, []load
 		fn = func(ctxt *Link, sect *sym.Section, syms []loader.Sym) {
 			wg.Add(1)
 			sem <- 1
-			out, err := ctxt.Out.View(sect.Reloff)
-			if err != nil {
-				panic(err)
-			}
+			out := ctxt.Out.View(sect.Reloff)
 			go func() {
 				relocSect(ctxt, out, sect, syms)
 				wg.Done()
diff --git a/src/cmd/link/internal/ld/data.go b/src/cmd/link/internal/ld/data.go
index 939de11876..42756e86bb 100644
--- a/src/cmd/link/internal/ld/data.go
+++ b/src/cmd/link/internal/ld/data.go
@@ -1063,7 +1063,8 @@ func writeBlocks(ctxt *Link, out *OutBuf, sem chan int, ldr *loader.Loader, syms
 		}
 
 		// Start the block output operator.
-		if o, err := out.View(uint64(out.Offset() + written)); err == nil {
+		if ctxt.Out.isMmapped() {
+			o := out.View(uint64(out.Offset() + written))
 			sem <- 1
 			wg.Add(1)
 			go func(o *OutBuf, ldr *loader.Loader, syms []loader.Sym, addr, size int64, pad []byte) {
@@ -1142,15 +1143,16 @@ type writeFn func(*Link, *OutBuf, int64, int64)
 
 // writeParallel handles scheduling parallel execution of data write functions.
 func writeParallel(wg *sync.WaitGroup, fn writeFn, ctxt *Link, seek, vaddr, length uint64) {
-	if out, err := ctxt.Out.View(seek); err != nil {
-		ctxt.Out.SeekSet(int64(seek))
-		fn(ctxt, ctxt.Out, int64(vaddr), int64(length))
-	} else {
+	if ctxt.Out.isMmapped() {
+		out := ctxt.Out.View(seek)
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
 			fn(ctxt, out, int64(vaddr), int64(length))
 		}()
+	} else {
+		ctxt.Out.SeekSet(int64(seek))
+		fn(ctxt, ctxt.Out, int64(vaddr), int64(length))
 	}
 }
 
diff --git a/src/cmd/link/internal/ld/outbuf.go b/src/cmd/link/internal/ld/outbuf.go
index 54fafcaf99..8732fcc5fe 100644
--- a/src/cmd/link/internal/ld/outbuf.go
+++ b/src/cmd/link/internal/ld/outbuf.go
@@ -92,9 +92,7 @@ func NewOutBuf(arch *sys.Arch) *OutBuf {
 	}
 }
 
-var viewError = errors.New("output not mmapped")
-
-func (out *OutBuf) View(start uint64) (*OutBuf, error) {
+func (out *OutBuf) View(start uint64) *OutBuf {
 	return &OutBuf{
 		arch:   out.arch,
 		name:   out.name,
@@ -102,7 +100,7 @@ func (out *OutBuf) View(start uint64) (*OutBuf, error) {
 		heap:   out.heap,
 		off:    int64(start),
 		isView: true,
-	}, nil
+	}
 }
 
 var viewCloseError = errors.New("cannot Close OutBuf from View")