| // Copyright 2016 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. |
| |
| // This program generates a test to verify that a program can be |
| // successfully linked even when there are very large text |
| // sections present. |
| |
| package main |
| |
| import ( |
| "bytes" |
| "cmd/internal/obj" |
| "fmt" |
| "io/ioutil" |
| "os" |
| "os/exec" |
| "testing" |
| ) |
| |
| func TestLargeText(t *testing.T) { |
| |
| var w bytes.Buffer |
| |
| if testing.Short() || (obj.GOARCH != "ppc64le" && obj.GOARCH != "ppc64") { |
| t.Skip("Skipping large text section test in short mode or if not ppc64x") |
| } |
| const FN = 4 |
| tmpdir, err := ioutil.TempDir("", "bigtext") |
| |
| defer os.RemoveAll(tmpdir) |
| |
| // Generate the scenario where the total amount of text exceeds the |
| // limit for the bl instruction, on RISC architectures like ppc64le, |
| // which is 2^26. When that happens the call requires special trampolines or |
| // long branches inserted by the linker where supported. |
| |
| // Multiple .s files are generated instead of one. |
| |
| for j := 0; j < FN; j++ { |
| testname := fmt.Sprintf("bigfn%d", j) |
| fmt.Fprintf(&w, "TEXT ยท%s(SB),$0\n", testname) |
| for i := 0; i < 2200000; i++ { |
| fmt.Fprintf(&w, "\tMOVD\tR0,R3\n") |
| } |
| fmt.Fprintf(&w, "\tRET\n") |
| err := ioutil.WriteFile(tmpdir+"/"+testname+".s", w.Bytes(), 0666) |
| if err != nil { |
| t.Fatalf("can't write output: %v\n", err) |
| } |
| w.Reset() |
| } |
| fmt.Fprintf(&w, "package main\n") |
| fmt.Fprintf(&w, "\nimport (\n") |
| fmt.Fprintf(&w, "\t\"os\"\n") |
| fmt.Fprintf(&w, "\t\"fmt\"\n") |
| fmt.Fprintf(&w, ")\n\n") |
| |
| for i := 0; i < FN; i++ { |
| fmt.Fprintf(&w, "func bigfn%d()\n", i) |
| } |
| fmt.Fprintf(&w, "\nfunc main() {\n") |
| |
| // There are lots of dummy code generated in the .s files just to generate a lot |
| // of text. Link them in but guard their call so their code is not executed but |
| // the main part of the program can be run. |
| |
| fmt.Fprintf(&w, "\tif os.Getenv(\"LINKTESTARG\") != \"\" {\n") |
| for i := 0; i < FN; i++ { |
| fmt.Fprintf(&w, "\t\tbigfn%d()\n", i) |
| } |
| fmt.Fprintf(&w, "\t}\n") |
| fmt.Fprintf(&w, "\tfmt.Printf(\"PASS\\n\")\n") |
| fmt.Fprintf(&w, "}") |
| err = ioutil.WriteFile(tmpdir+"/bigfn.go", w.Bytes(), 0666) |
| if err != nil { |
| t.Fatalf("can't write output: %v\n", err) |
| } |
| |
| os.Chdir(tmpdir) |
| cmd := exec.Command("go", "build", "-o", "bigtext", "-ldflags", "'-linkmode=external'") |
| out, err := cmd.CombinedOutput() |
| if err != nil { |
| t.Fatalf("Build of big text program failed: %v, output: %s", err, out) |
| } |
| cmd = exec.Command(tmpdir + "/bigtext") |
| out, err = cmd.CombinedOutput() |
| if err != nil { |
| t.Fatalf("Program failed with err %v, output: %s", err, out) |
| } |
| } |