Add a script to reduce source files to required set

build/strip_cmakelists.sh

+cd $(dirname $0)
+go run strip_unneeded.go --file=../CMakeLists.txt --test="cmake -DREACTOR_BACKEND=LLVM -DREACTOR_EMIT_DEBUG_INFO=1 .. && cmake --build ."
\ No newline at end of file

build/strip_unneeded.go

+// Copyright 2019 The SwiftShader Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// strip_unneeded is a tool that attempts to remove unnecessary lines from a
+// file by running a test script after each marked line is removed.
+//
+// strip_unneeded will scan the file specified by the --file argument for lines
+// that contain the substring specified by the --marker argument. One-by-one
+// those marked lines will be removed from the file, after which the test script
+// specified by --test will be run. If the test passes (the process completes
+// with a 0 return code), then the line will remain removed, otherwise it is
+// restored. This will repeat for every line in the file containing the marker,
+// until all lines are tested.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+var (
+	file   = flag.String("file", "", "file to modify")
+	marker = flag.String("marker", "CHECK_NEEDED", "line token")
+	test   = flag.String("test", "", "test script to run with each change")
+)
+
+func main() {
+	if err := run(); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+}
+
+func run() error {
+	flag.Parse()
+	if *file == "" {
+		return fmt.Errorf("Missing --file argument")
+	}
+	if *marker == "" {
+		return fmt.Errorf("Missing --marker argument")
+	}
+	if *test == "" {
+		return fmt.Errorf("Missing --test argument")
+	}
+
+	// make sure the test passes with no modifications
+	if err := runTest(); err != nil {
+		return fmt.Errorf("Test fails with no modifications.\n%v", err)
+	}
+
+	// load the test file
+	body, err := ioutil.ReadFile(*file)
+	if err != nil {
+		return fmt.Errorf("Couldn't load file '%v'", *file)
+	}
+
+	// gather all the lines
+	allLines := strings.Split(string(body), "\n")
+
+	// find all the lines with the marker
+	markerLines := make([]int, 0, len(allLines))
+	for i, l := range allLines {
+		if strings.Contains(l, *marker) {
+			markerLines = append(markerLines, i)
+		}
+	}
+
+	omit := map[int]bool{}
+
+	save := func() error {
+		f, err := os.Create(*file)
+		if err != nil {
+			return err
+		}
+		defer f.Close()
+		for i, l := range allLines {
+			if !omit[i] {
+				f.WriteString(l)
+				f.WriteString("\n")
+			}
+		}
+		return nil
+	}
+
+	for i, l := range markerLines {
+		omit[l] = true
+		if err := save(); err != nil {
+			return err
+		}
+		if err := runTest(); err != nil {
+			omit[l] = false
+			fmt.Printf("%d/%d: Test fails when removing line %v: %v\n", i, len(markerLines), l, allLines[l])
+		} else {
+			fmt.Printf("%d/%d: Test passes when removing line %v: %v\n", i, len(markerLines), l, allLines[l])
+		}
+	}
+
+	return save()
+}
+
+func runTest() error {
+	cmd := exec.Command("sh", "-c", *test)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		return fmt.Errorf("Test failed with error: %v\n%v", err, string(out))
+	}
+	return nil
+}