cmd/compile: expand inlining test to multiple pkgs

Rework the test to work with any number of std packages. This was done
to include a few funcs from unicode/utf8. Adding more will be much
simpler too.

While at it, add more runtime funcs by searching for "inlined" or
"inlining" in the git log of its directory. These are: addb, subtractb,
fastrand and noescape.

Updates #21851.

Change-Id: I4fb2bd8aa6a5054218f9b36cb19d897ac533710e
Reviewed-on: https://go-review.googlesource.com/63611
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/compile/internal/gc/inl_test.go

@@ -21,28 +21,60 @@ func TestIntendedInlining(t *testing.T) {
 	testenv.MustHaveGoRun(t)
 	t.Parallel()
 
-	// want is the list of function names that should be inlined.
-	want := []string{"tophash", "add", "(*bmap).keys", "bucketShift", "bucketMask"}
+	// want is the list of function names (by package) that should
+	// be inlined.
+	want := map[string][]string{
+		"runtime": {
+			"tophash",
+			"add",
+			"addb",
+			"subtractb",
+			"(*bmap).keys",
+			"bucketShift",
+			"bucketMask",
+			"fastrand",
+			"noescape",
 
-	m := make(map[string]bool, len(want))
-	for _, s := range want {
-		m[s] = true
+			// TODO: These were modified at some point to be
+			// made inlineable, but have since been broken.
+			// "nextFreeFast",
+		},
+		"unicode/utf8": {
+			"FullRune",
+			"FullRuneInString",
+			"RuneLen",
+			"ValidRune",
+		},
 	}
 
-	cmd := testenv.CleanCmdEnv(exec.Command(testenv.GoToolPath(t), "build", "-a", "-gcflags=-m", "runtime"))
+	m := make(map[string]bool)
+	pkgs := make([]string, 0, len(want))
+	for pname, fnames := range want {
+		pkgs = append(pkgs, pname)
+		for _, fname := range fnames {
+			m[pname+"."+fname] = true
+		}
+	}
+
+	args := append([]string{"build", "-a", "-gcflags=-m"}, pkgs...)
+	cmd := testenv.CleanCmdEnv(exec.Command(testenv.GoToolPath(t), args...))
 	out, err := cmd.CombinedOutput()
 	if err != nil {
 		t.Logf("%s", out)
 		t.Fatal(err)
 	}
 	lines := bytes.Split(out, []byte{'\n'})
-	for _, x := range lines {
-		f := bytes.Split(x, []byte(": can inline "))
+	curPkg := ""
+	for _, l := range lines {
+		if bytes.HasPrefix(l, []byte("# ")) {
+			curPkg = string(l[2:])
+		}
+		f := bytes.Split(l, []byte(": can inline "))
 		if len(f) < 2 {
 			continue
 		}
 		fn := bytes.TrimSpace(f[1])
-		delete(m, string(fn))
+		delete(m, curPkg+"."+string(fn))
 	}
 
 	for s := range m {