From: Cherry Mui <cherryyz@google.com>
Date: Tue, 22 Mar 2022 21:08:56 +0000 (-0400)
Subject: cmd/compile: default to -p=main for main package
X-Git-Tag: go1.19beta1~952
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=20ba3f5de52bf8665d35c86111312274f6a4d1be;p=gostls13.git

cmd/compile: default to -p=main for main package

With the previous CL the compiler emits an unlinkable object if
the -p flag is not specified. It is actually okay (and convenient)
to omit the -p flag for (just) the main package. This CL makes it
so.

Change-Id: I978d54d14c45b3bb9ed7471e40a2c47f269b56f7
Reviewed-on: https://go-review.googlesource.com/c/go/+/394834
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
---

diff --git a/src/cmd/compile/internal/gc/main.go b/src/cmd/compile/internal/gc/main.go
index 5a9a889894..1f547130ad 100644
--- a/src/cmd/compile/internal/gc/main.go
+++ b/src/cmd/compile/internal/gc/main.go
@@ -188,6 +188,9 @@ func Main(archInit func(*ssagen.ArchInfo)) {
 
 	// Parse and typecheck input.
 	noder.LoadPackage(flag.Args())
+	if base.Ctxt.Pkgpath == obj.UnlinkablePkg && types.LocalPkg.Name == "main" {
+		base.Ctxt.Pkgpath = "main"
+	}
 
 	dwarfgen.RecordPackageName()
 
diff --git a/src/cmd/link/link_test.go b/src/cmd/link/link_test.go
index 2eefc5c8e7..8df31d7fd4 100644
--- a/src/cmd/link/link_test.go
+++ b/src/cmd/link/link_test.go
@@ -1067,19 +1067,30 @@ func TestUnlinkableObj(t *testing.T) {
 
 	tmpdir := t.TempDir()
 
-	src := filepath.Join(tmpdir, "x.go")
-	obj := filepath.Join(tmpdir, "x.o")
+	xSrc := filepath.Join(tmpdir, "x.go")
+	pSrc := filepath.Join(tmpdir, "p.go")
+	xObj := filepath.Join(tmpdir, "x.o")
+	pObj := filepath.Join(tmpdir, "p.o")
 	exe := filepath.Join(tmpdir, "x.exe")
-	err := ioutil.WriteFile(src, []byte("package main\nfunc main() {}\n"), 0666)
+	err := ioutil.WriteFile(xSrc, []byte("package main\nimport _ \"p\"\nfunc main() {}\n"), 0666)
 	if err != nil {
 		t.Fatalf("failed to write source file: %v", err)
 	}
-	cmd := exec.Command(testenv.GoToolPath(t), "tool", "compile", "-o", obj, src) // without -p
+	err = ioutil.WriteFile(pSrc, []byte("package p\n"), 0666)
+	if err != nil {
+		t.Fatalf("failed to write source file: %v", err)
+	}
+	cmd := exec.Command(testenv.GoToolPath(t), "tool", "compile", "-o", pObj, pSrc) // without -p
 	out, err := cmd.CombinedOutput()
 	if err != nil {
-		t.Fatalf("compile failed: %v. output:\n%s", err, out)
+		t.Fatalf("compile p.go failed: %v. output:\n%s", err, out)
 	}
-	cmd = exec.Command(testenv.GoToolPath(t), "tool", "link", "-o", exe, obj)
+	cmd = exec.Command(testenv.GoToolPath(t), "tool", "compile", "-I", tmpdir, "-p=main", "-o", xObj, xSrc)
+	out, err = cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("compile x.go failed: %v. output:\n%s", err, out)
+	}
+	cmd = exec.Command(testenv.GoToolPath(t), "tool", "link", "-L", tmpdir, "-o", exe, xObj)
 	out, err = cmd.CombinedOutput()
 	if err == nil {
 		t.Fatalf("link did not fail")
@@ -1087,4 +1098,21 @@ func TestUnlinkableObj(t *testing.T) {
 	if !bytes.Contains(out, []byte("unlinkable object")) {
 		t.Errorf("did not see expected error message. out:\n%s", out)
 	}
+
+	// It is okay to omit -p for (only) main package.
+	cmd = exec.Command(testenv.GoToolPath(t), "tool", "compile", "-p=p", "-o", pObj, pSrc)
+	out, err = cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("compile p.go failed: %v. output:\n%s", err, out)
+	}
+	cmd = exec.Command(testenv.GoToolPath(t), "tool", "compile", "-I", tmpdir, "-o", xObj, xSrc) // without -p
+	out, err = cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("compile failed: %v. output:\n%s", err, out)
+	}
+	cmd = exec.Command(testenv.GoToolPath(t), "tool", "link", "-L", tmpdir, "-o", exe, xObj)
+	out, err = cmd.CombinedOutput()
+	if err != nil {
+		t.Errorf("link failed: %v. output:\n%s", err, out)
+	}
 }