1 files changed, 73 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/test/inst_test.go b/src/cmd/compile/internal/test/inst_test.go
new file mode 100644
index 0000000..951f6a0
--- /dev/null
+++ b/src/cmd/compile/internal/test/inst_test.go
@@ -0,0 +1,73 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package test
+
+import (
+	"internal/goexperiment"
+	"internal/testenv"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"testing"
+)
+
+// TestInst tests that only one instantiation of Sort is created, even though generic
+// Sort is used for multiple pointer types across two packages.
+func TestInst(t *testing.T) {
+	if goexperiment.Unified {
+		t.Skip("unified currently does stenciling, not dictionaries")
+	}
+	testenv.MustHaveGoBuild(t)
+	testenv.MustHaveGoRun(t)
+
+	var tmpdir string
+	var err error
+	tmpdir, err = ioutil.TempDir("", "TestDict")
+	if err != nil {
+		t.Fatalf("Failed to create temporary directory: %v", err)
+	}
+	defer os.RemoveAll(tmpdir)
+
+	// Build ptrsort.go, which uses package mysort.
+	var output []byte
+	filename := "ptrsort.go"
+	exename := "ptrsort"
+	outname := "ptrsort.out"
+	gotool := testenv.GoToolPath(t)
+	dest := filepath.Join(tmpdir, exename)
+	cmd := exec.Command(gotool, "build", "-o", dest, filepath.Join("testdata", filename))
+	if output, err = cmd.CombinedOutput(); err != nil {
+		t.Fatalf("Failed: %v:\nOutput: %s\n", err, output)
+	}
+
+	// Test that there is exactly one shape-based instantiation of Sort in
+	// the executable.
+	cmd = exec.Command(gotool, "tool", "nm", dest)
+	if output, err = cmd.CombinedOutput(); err != nil {
+		t.Fatalf("Failed: %v:\nOut: %s\n", err, output)
+	}
+	// Look for shape-based instantiation of Sort, but ignore any extra wrapper
+	// ending in "-tramp" (which are created on riscv).
+	re := regexp.MustCompile(`\bSort\[.*shape.*\][^-]`)
+	r := re.FindAllIndex(output, -1)
+	if len(r) != 1 {
+		t.Fatalf("Wanted 1 instantiations of Sort function, got %d\n", len(r))
+	}
+
+	// Actually run the test and make sure output is correct.
+	cmd = exec.Command(gotool, "run", filepath.Join("testdata", filename))
+	if output, err = cmd.CombinedOutput(); err != nil {
+		t.Fatalf("Failed: %v:\nOut: %s\n", err, output)
+	}
+	out, err := ioutil.ReadFile(filepath.Join("testdata", outname))
+	if err != nil {
+		t.Fatalf("Could not find %s\n", outname)
+	}
+	if string(out) != string(output) {
+		t.Fatalf("Wanted output %v, got %v\n", string(out), string(output))
+	}
+}