dtoc: Save scan information across test runs

At present most of the tests scan the U-Boot source tree as part of their
run. This information does not change across tests, so we can save time
by remembering it.

Add a way to set up this information and use it for each test, taking a
copy first, so as not to mess up the original.

This reduces the run time from about 1.6 seconds to 1.5 seconds on my
machine. For code coverage (which cannot run in parallel), it reduces from
33 seconds to 5.

Signed-off-by: Simon Glass <sjg@chromium.org>

tools/dtoc/dtb_platdata.py

@@ -670,7 +670,8 @@ OUTPUT_FILES = {
 
 
 def run_steps(args, dtb_file, include_disabled, output, output_dirs,
-              warning_disabled=False, drivers_additional=None, basedir=None):
+              warning_disabled=False, drivers_additional=None, basedir=None,
+              scan=None):
     """Run all the steps of the dtoc tool
 
     Args:
@@ -687,6 +688,9 @@ def run_steps(args, dtb_file, include_disabled, output, output_dirs,
             scanning
         basedir (str): Base directory of U-Boot source code. Defaults to the
             grandparent of this file's directory
+        scan (src_src.Scanner): Scanner from a previous run. This can help speed
+            up tests. Use None for normal operation
+
     Raises:
         ValueError: if args has no command, or an unknown command
     """
@@ -695,9 +699,10 @@ def run_steps(args, dtb_file, include_disabled, output, output_dirs,
     if output and output_dirs and any(output_dirs):
         raise ValueError('Must specify either output or output_dirs, not both')
 
-    scan = src_scan.Scanner(basedir, warning_disabled, drivers_additional)
+    if not scan:
+        scan = src_scan.Scanner(basedir, warning_disabled, drivers_additional)
+        scan.scan_drivers()
     plat = DtbPlatdata(scan, dtb_file, include_disabled)
-    scan.scan_drivers()
     plat.scan_dtb()
     plat.scan_tree()
     plat.scan_reg_sizes()

tools/dtoc/main.py

@@ -53,6 +53,8 @@ def run_tests(processes, args):
     sys.argv = [sys.argv[0]]
     test_name = args and args[0] or None
 
+    test_dtoc.setup()
+
     test_util.RunTestSuites(
         result, debug=True, verbosity=1, test_preserve_dirs=False,
         processes=processes, test_name=test_name, toolpath=[],

tools/dtoc/test_dtoc.py

@@ -10,6 +10,7 @@ tool.
 """
 
 import collections
+import copy
 import glob
 import os
 import struct
@@ -20,6 +21,7 @@ from dtb_platdata import tab_to
 from dtoc import dtb_platdata
 from dtoc import fdt
 from dtoc import fdt_util
+from dtoc import src_scan
 from dtoc.src_scan import conv_name_to_c
 from dtoc.src_scan import get_compat_name
 from patman import test_util
@@ -53,6 +55,9 @@ C_HEADER = '''/*
 #include <dt-structs.h>
 '''
 
+# Scanner saved from a previous run of the tests (to speed things up)
+saved_scan = None
+
 # This is a test so is allowed to access private things in the module it is
 # testing
 # pylint: disable=W0212
@@ -71,6 +76,19 @@ def get_dtb_file(dts_fname, capture_stderr=False):
                                    capture_stderr=capture_stderr)
 
 
+def setup():
+    global saved_scan
+
+    # Disable warnings so that calls to get_normalized_compat_name() will not
+    # output things.
+    saved_scan = src_scan.Scanner(None, True, False)
+    saved_scan.scan_drivers()
+
+def copy_scan():
+    """Get a copy of saved_scan so that each test can start clean"""
+    return copy.deepcopy(saved_scan)
+
+
 class TestDtoc(unittest.TestCase):
     """Tests for dtoc"""
     @classmethod
@@ -120,7 +138,8 @@ class TestDtoc(unittest.TestCase):
             dtb_file (str): Filename of .dtb file
             output (str): Filename of output file
         """
-        dtb_platdata.run_steps(args, dtb_file, False, output, [], True)
+        dtb_platdata.run_steps(args, dtb_file, False, output, [], True,
+                               None, None, scan=copy_scan())
 
     def test_name(self):
         """Test conversion of device tree names to C identifiers"""
@@ -175,7 +194,9 @@ class TestDtoc(unittest.TestCase):
         """Test output from a device tree file with no nodes"""
         dtb_file = get_dtb_file('dtoc_test_empty.dts')
         output = tools.GetOutputFilename('output')
-        self.run_test(['struct'], dtb_file, output)
+
+        # Run this one without saved_scan to complete test coverage
+        dtb_platdata.run_steps(['struct'], dtb_file, False, output, [], True)
         with open(output) as infile:
             lines = infile.read().splitlines()
         self.assertEqual(HEADER.splitlines(), lines)
@@ -343,7 +364,8 @@ U_BOOT_DRVINFO(gpios_at_0) = {
         dtb_file = get_dtb_file('dtoc_test_invalid_driver.dts')
         output = tools.GetOutputFilename('output')
         with test_util.capture_sys_output() as _:
-            dtb_platdata.run_steps(['struct'], dtb_file, False, output, [])
+            dtb_platdata.run_steps(['struct'], dtb_file, False, output, [],
+                                   scan=copy_scan())
         with open(output) as infile:
             data = infile.read()
         self._check_strings(HEADER + '''
@@ -352,7 +374,8 @@ struct dtd_invalid {
 ''', data)
 
         with test_util.capture_sys_output() as _:
-            dtb_platdata.run_steps(['platdata'], dtb_file, False, output, [])
+            dtb_platdata.run_steps(['platdata'], dtb_file, False, output, [],
+                                   scan=copy_scan())
         with open(output) as infile:
             data = infile.read()
         self._check_strings(C_HEADER + '''
@@ -502,7 +525,8 @@ U_BOOT_DRVINFO(phandle_target) = {
         """Test that phandle targets are generated when unsing cd-gpios"""
         dtb_file = get_dtb_file('dtoc_test_phandle_cd_gpios.dts')
         output = tools.GetOutputFilename('output')
-        dtb_platdata.run_steps(['platdata'], dtb_file, False, output, [], True)
+        dtb_platdata.run_steps(['platdata'], dtb_file, False, output, [], True,
+                               scan=copy_scan())
         with open(output) as infile:
             data = infile.read()
         self._check_strings(C_HEADER + '''
@@ -903,7 +927,8 @@ U_BOOT_DRVINFO(spl_test2) = {
     def test_output_conflict(self):
         """Test a conflict between and output dirs and output file"""
         with self.assertRaises(ValueError) as exc:
-            dtb_platdata.run_steps(['all'], None, False, 'out', ['cdir'], True)
+            dtb_platdata.run_steps(['all'], None, False, 'out', ['cdir'], True,
+                                   scan=copy_scan())
         self.assertIn("Must specify either output or output_dirs, not both",
                       str(exc.exception))
 
@@ -919,7 +944,8 @@ U_BOOT_DRVINFO(spl_test2) = {
         fnames = glob.glob(outdir + '/*')
         self.assertEqual(2, len(fnames))
 
-        dtb_platdata.run_steps(['all'], dtb_file, False, None, [outdir], True)
+        dtb_platdata.run_steps(['all'], dtb_file, False, None, [outdir], True,
+                               scan=copy_scan())
         fnames = glob.glob(outdir + '/*')
         self.assertEqual(4, len(fnames))