Function testTransform

transform/transform_test.go:31–78

testTransform runs a transformation pass on an input file (pathPrefix+".ll") and checks whether it matches the expected output (pathPrefix+".out.ll"). The output is compared with a fuzzy match that ignores some irrelevant lines such as empty lines.

(t *testing.T, pathPrefix string, transform func(mod llvm.Module))

// output is compared with a fuzzy match that ignores some irrelevant lines such
// as empty lines.
func testTransform(t *testing.T, pathPrefix string, transform func(mod llvm.Module)) {
	// Read the input IR.
	ctx := llvm.NewContext()
	defer ctx.Dispose()
	buf, err := llvm.NewMemoryBufferFromFile(pathPrefix + ".ll")
	os.Stat(pathPrefix + ".ll") // make sure this file is tracked by `go test` caching
	if err != nil {
		t.Fatalf("could not read file %s: %v", pathPrefix+".ll", err)
	}
	mod, err := ctx.ParseIR(buf)
	if err != nil {
		t.Fatalf("could not load module:\n%v", err)
	}
	defer mod.Dispose()

	// Perform the transform.
	transform(mod)

	// Check for any incorrect IR.
	err = llvm.VerifyModule(mod, llvm.PrintMessageAction)
	if err != nil {
		t.Fatal("IR verification failed")
	}

	// Get the output from the test and filter some irrelevant lines.
	actual := mod.String()
	actual = actual[strings.Index(actual, "\ntarget datalayout = ")+1:]

	if *update {
		err := os.WriteFile(pathPrefix+".out.ll", []byte(actual), 0666)
		if err != nil {
			t.Error("failed to write out new output:", err)
		}
	} else {
		// Read the expected output IR.
		out, err := os.ReadFile(pathPrefix + ".out.ll")
		if err != nil {
			t.Fatalf("could not read output file %s: %v", pathPrefix+".out.ll", err)
		}

		// See whether the transform output matches with the expected output IR.
		expected := string(out)
		if !fuzzyEqualIR(expected, actual) {
			t.Logf("output does not match expected output:\n%s", actual)
			t.Fail()
		}
	}
}

// fuzzyEqualIR returns true if the two LLVM IR strings passed in are roughly
// equal. That means, only relevant lines are compared (excluding comments