diff --git a/BUILD.gn b/BUILD.gn
index a027a2e6150..7d1f7fd8764 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -70,12 +70,13 @@ action("create_sdk") {
   ]
 
   sdk_lib_files = exec_script("tools/list_dart_files.py",
-                              [ rebase_path("sdk/lib") ],
+                              [ "absolute", rebase_path("sdk/lib") ],
                               "list lines")
 
   preamble_files =
       exec_script("tools/list_files.py",
                   [
+                    "absolute",
                     "",
                     rebase_path("sdk/lib/_internal/js_runtime/lib/preambles"),
                   ],
@@ -83,14 +84,13 @@ action("create_sdk") {
 
   sdk_bin_files = exec_script("tools/list_files.py",
                               [
+                                "absolute",
                                 "",
                                 rebase_path("sdk/bin"),
                               ],
                               "list lines")
 
-  inputs = rebase_path(sdk_lib_files, "", "sdk/lib") +
-           rebase_path(preamble_files, "", "sdk/lib") +
-           rebase_path(sdk_bin_files, "", "sdk/bin") +
+  inputs = sdk_lib_files + preamble_files + sdk_bin_files +
            [
              "sdk/lib/dart_client.platform",
              "sdk/lib/dart_server.platform",
diff --git a/create_sdk.gyp b/create_sdk.gyp
index b1b9361ddda..9e41ef91ee6 100644
--- a/create_sdk.gyp
+++ b/create_sdk.gyp
@@ -23,15 +23,15 @@
           'inputs': [
             # Xcode can only handle a certain amount of files in one list
             # (also depending on the length of the path from where you run).
-            '<!@(["python", "tools/list_files.py",'
-                '"dart$",'
+            '<!@(["python", "tools/list_files.py", "relative", "dart$",'
                 '"sdk/lib"])',
             'sdk/lib/dart_client.platform',
             'sdk/lib/dart_server.platform',
             'sdk/lib/dart_shared.platform',
-            '<!@(["python", "tools/list_files.py", "", '
+            '<!@(["python", "tools/list_files.py", "relative", "", '
                 '"sdk/lib/_internal/js_runtime/lib/preambles"])',
-            '<!@(["python", "tools/list_files.py", "", "sdk/bin"])',
+            '<!@(["python", "tools/list_files.py", "relative",  "", '
+                '"sdk/bin"])',
             'tools/create_sdk.py',
             '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)dart<(EXECUTABLE_SUFFIX)',
             '<(SHARED_INTERMEDIATE_DIR)/dart2js.dart.snapshot',
diff --git a/pkg/BUILD.gn b/pkg/BUILD.gn
index e1ce11d2e4e..bd7eb4ca87a 100644
--- a/pkg/BUILD.gn
+++ b/pkg/BUILD.gn
@@ -16,7 +16,6 @@ template("make_third_party_pkg_files_stamp") {
       pattern = invoker.pattern
     }
     path = path
-    new_base = "//"
     output = "$target_gen_dir/third_party_pkg_files_$id.stamp"
   }
 }
diff --git a/pkg/pkg_files.gyp b/pkg/pkg_files.gyp
index 55dd28467b8..9e41a67fe64 100644
--- a/pkg/pkg_files.gyp
+++ b/pkg/pkg_files.gyp
@@ -19,7 +19,7 @@
           'action_name': 'make_pkg_files_stamp',
           'inputs': [
             '../tools/create_timestamp_file.py',
-            '<!@(["python", "../tools/list_dart_files.py", "."])',
+            '<!@(["python", "../tools/list_dart_files.py", "relative", "."])',
             '<(SHARED_INTERMEDIATE_DIR)/third_party_pkg_files_a_k.stamp',
             '<(SHARED_INTERMEDIATE_DIR)/third_party_pkg_files_l_r.stamp',
             '<(SHARED_INTERMEDIATE_DIR)/third_party_pkg_files_s_z.stamp',
@@ -36,7 +36,8 @@
           'action_name': 'make_third_party_pkg_files_a_k_stamp',
           'inputs': [
             '../tools/create_timestamp_file.py',
-            '<!@(["python", "../tools/list_dart_files.py", "../third_party/pkg", "[a-k].*"])',
+            '<!@(["python", "../tools/list_dart_files.py", "relative", '
+                '"../third_party/pkg", "[a-k].*"])',
           ],
           'outputs': [
             '<(SHARED_INTERMEDIATE_DIR)/third_party_pkg_files_a_k.stamp',
@@ -50,7 +51,8 @@
           'action_name': 'make_third_party_pkg_files_l_r_stamp',
           'inputs': [
             '../tools/create_timestamp_file.py',
-            '<!@(["python", "../tools/list_dart_files.py", "../third_party/pkg", "[l-r].*"])',
+            '<!@(["python", "../tools/list_dart_files.py", "relative", '
+                '"../third_party/pkg", "[l-r].*"])',
           ],
           'outputs': [
             '<(SHARED_INTERMEDIATE_DIR)/third_party_pkg_files_l_r.stamp',
@@ -64,7 +66,8 @@
           'action_name': 'make_third_party_pkg_files_s_z_stamp',
           'inputs': [
             '../tools/create_timestamp_file.py',
-            '<!@(["python", "../tools/list_dart_files.py", "../third_party/pkg", "[s-z].*"])',
+            '<!@(["python", "../tools/list_dart_files.py", "relative", '
+                '"../third_party/pkg", "[s-z].*"])',
           ],
           'outputs': [
             '<(SHARED_INTERMEDIATE_DIR)/third_party_pkg_files_s_z.stamp',
diff --git a/runtime/vm/BUILD.gn b/runtime/vm/BUILD.gn
index 9bbc3a49538..bf3a4537b27 100644
--- a/runtime/vm/BUILD.gn
+++ b/runtime/vm/BUILD.gn
@@ -411,10 +411,13 @@ if (!defined(is_fuchsia) || !is_fuchsia) {
 
       script = "../../tools/patch_sdk.py"
 
-      # We list all files which make up the sdk (modulo patches) and get them back
-      # as a GN list object.
+      # We list all files which make up the sdk (modulo patches) and get them
+      # back as a GN list object.
       shared_sdk_sources = exec_script("../../tools/list_dart_files.py",
-                                       [ "../../sdk/lib" ],
+                                       [
+                                         "absolute",
+                                         rebase_path("../../sdk/lib"),
+                                       ],
                                        "list lines")
 
       # We list the `patch_sdk.dart` tool here because the [script] (which is
@@ -423,8 +426,8 @@ if (!defined(is_fuchsia) || !is_fuchsia) {
         "../../tools/patch_sdk.dart",
       ]
 
-      # Files below are not patches, they will not be in [concatenation_files] but
-      # the `patch_sdk.dart` script will copy them into the patched sdk.
+      # Files below are not patches, they will not be in [concatenation_files]
+      # but the `patch_sdk.dart` script will copy them into the patched sdk.
       inputs += [
         "../lib/typed_data.dart",
         "../bin/builtin.dart",
diff --git a/runtime/vm/vm.gypi b/runtime/vm/vm.gypi
index a072f6530ad..3da329123e9 100644
--- a/runtime/vm/vm.gypi
+++ b/runtime/vm/vm.gypi
@@ -1261,7 +1261,8 @@
         {
           'action_name': 'patch_sdk',
           'inputs': [
-            '<!@(["python", "../tools/list_files.py",' '"dart$",' '"sdk/lib"])',
+            '<!@(["python", "../tools/list_files.py", "relative",'
+                  '"dart$", "sdk/lib"])',
             '../../tools/patch_sdk.py',
             '../../tools/patch_sdk.dart',
             # Unlike the other libraries in the SDK, dart:typed_data is not
diff --git a/tools/list_dart_files.py b/tools/list_dart_files.py
index 60d2295652e..7a9ee8ab6c0 100755
--- a/tools/list_dart_files.py
+++ b/tools/list_dart_files.py
@@ -5,8 +5,12 @@
 
 """Tool for listing Dart source files.
 
+If the first argument is 'relative', the script produces paths relative to the
+current working directory. If the first argument is 'absolute', the script
+produces absolute paths.
+
 Usage:
-  python tools/list_dart_files.py <directory> <root directory pattern>
+  python tools/list_dart_files.py {absolute, relative} <directory> <pattern>
 """
 
 import os
@@ -15,11 +19,16 @@ import sys
 
 
 def main(argv):
-  directory = argv[1]
+  mode = argv[1]
+  if mode not in ['absolute', 'relative']:
+    raise Exception("First argument must be 'absolute' or 'relative'")
+  directory = argv[2]
+  if mode in 'absolute' and not os.path.isabs(directory):
+    directory = os.path.realpath(directory)
 
   pattern = None
-  if len(argv) > 2:
-    pattern = re.compile(argv[2])
+  if len(argv) > 3:
+    pattern = re.compile(argv[3])
 
   for root, directories, files in os.walk(directory):
     # We only care about actual source files, not generated code or tests.
@@ -34,7 +43,10 @@ def main(argv):
 
     for filename in files:
       if filename.endswith('.dart') and not filename.endswith('_test.dart'):
-        fullname = os.path.relpath(os.path.join(root, filename))
+        if mode in 'absolute':
+          fullname = os.path.join(directory, root, filename)
+        else:
+          fullname = os.path.relpath(os.path.join(root, filename))
         fullname = fullname.replace(os.sep, '/')
         print fullname
 
diff --git a/tools/list_files.py b/tools/list_files.py
index ad277e853f0..b63d6ab0e32 100755
--- a/tools/list_files.py
+++ b/tools/list_files.py
@@ -5,8 +5,12 @@
 
 """Tool for listing files whose name match a pattern.
 
+If the first argument is 'relative', the script produces paths relative to the
+current working directory. If the first argument is 'absolute', the script
+produces absolute paths.
+
 Usage:
-  python tools/list_files.py PATTERN DIRECTORY...
+  python tools/list_files.py {absolute, relative} PATTERN DIRECTORY...
 """
 
 import os
@@ -15,13 +19,21 @@ import sys
 
 
 def main(argv):
-  pattern = re.compile(argv[1])
-  for directory in argv[2:]:
+  mode = argv[1]
+  if mode not in ['absolute', 'relative']:
+    raise Exception("First argument must be 'absolute' or 'relative'")
+  pattern = re.compile(argv[2])
+  for directory in argv[3:]:
+    if mode in 'absolute' and not os.path.isabs(directory):
+      directory = os.path.realpath(directory)
     for root, directories, files in os.walk(directory):
       if '.git' in directories:
         directories.remove('.git')
       for filename in files:
-        fullname = os.path.relpath(os.path.join(root, filename))
+        if mode in 'absolute':
+          fullname = os.path.join(directory, root, filename)
+        else:
+          fullname = os.path.relpath(os.path.join(root, filename))
         fullname = fullname.replace(os.sep, '/')
         if re.search(pattern, fullname):
           print fullname
diff --git a/utils/compiler/compiler.gyp b/utils/compiler/compiler.gyp
index 63c4daeb36d..272dd0aa137 100644
--- a/utils/compiler/compiler.gyp
+++ b/utils/compiler/compiler.gyp
@@ -20,7 +20,10 @@
           'inputs': [
             '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)dart<(EXECUTABLE_SUFFIX)',
             '../../sdk/lib/_internal/sdk_library_metadata/lib/libraries.dart',
-            '<!@(["python", "../../tools/list_files.py", "\\.dart$", "../../runtime/lib", "../../sdk/lib/_internal/dartdoc"])',
+            '<!@(["python", "../../tools/list_files.py",  "relative", '
+                '"\\.dart$", '
+                '"../../runtime/lib", '
+                '"../../sdk/lib/_internal/dartdoc"])',
             'create_snapshot.dart',
             '<(SHARED_INTERMEDIATE_DIR)/dart2js_files.stamp',
             '../../tools/VERSION',
@@ -51,7 +54,8 @@
           'action_name': 'make_dart2js_files_stamp',
           'inputs': [
             '../../tools/create_timestamp_file.py',
-            '<!@(["python", "../../tools/list_files.py", "\\.dart$",'
+            '<!@(["python", "../../tools/list_files.py", "relative", '
+                '"\\.dart$", '
                 ' "../../pkg/compiler/lib"])',
           ],
           'outputs': [
diff --git a/utils/create_timestamp.gni b/utils/create_timestamp.gni
index c579da1e5e3..75ae4cda7a5 100644
--- a/utils/create_timestamp.gni
+++ b/utils/create_timestamp.gni
@@ -7,14 +7,6 @@ _dart_root = rebase_path("..")
 template("create_timestamp_file") {
   assert(defined(invoker.path), "Must specify 'path'")
   assert(defined(invoker.output), "Must specify 'output'")
-  new_base = "."
-  if (defined(invoker.new_base)) {
-    new_base = invoker.new_base
-  }
-  current_base = "."
-  if (defined(invoker.current_base)) {
-    current_base = invoker.current_base
-  }
   path = invoker.path
   output = invoker.output
   action(target_name) {
@@ -23,10 +15,9 @@ template("create_timestamp_file") {
       list_args += [ invoker.pattern ]
     }
     files = exec_script("$_dart_root/tools/list_dart_files.py",
-                        list_args,
+                        [ "absolute" ] + list_args,
                         "list lines")
-    inputs = [ "$_dart_root/tools/list_dart_files.py" ] +
-             rebase_path(files, new_base, current_base)
+    inputs = [ "$_dart_root/tools/list_dart_files.py" ] + files
     outputs = [
       output,
     ]
diff --git a/utils/dartanalyzer/BUILD.gn b/utils/dartanalyzer/BUILD.gn
index dbefeecc342..7ea889e05c3 100644
--- a/utils/dartanalyzer/BUILD.gn
+++ b/utils/dartanalyzer/BUILD.gn
@@ -14,7 +14,7 @@ group("dartanalyzer") {
 }
 
 analyzer_files = exec_script("../../tools/list_dart_files.py",
-                             [ rebase_path("../../pkg/analyzer") ],
+                             [ "absolute", rebase_path("../../pkg/analyzer") ],
                              "list lines")
 
 application_snapshot("generate_dartanalyzer_snapshot") {
@@ -25,13 +25,13 @@ application_snapshot("generate_dartanalyzer_snapshot") {
   ]
   name = "dartanalyzer"
   cli_files = exec_script("../../tools/list_dart_files.py",
-                          [ rebase_path("../../pkg/analyzer_cli") ],
+                          [ "absolute", rebase_path("../../pkg/analyzer_cli") ],
                           "list lines")
   inputs = cli_files + analyzer_files
 }
 
 sdk_lib_files = exec_script("../../tools/list_dart_files.py",
-                            [ rebase_path("../../sdk/lib") ],
+                            [ "absolute", rebase_path("../../sdk/lib") ],
                             "list lines")
 
 template("generate_summary") {
diff --git a/utils/dartanalyzer/dartanalyzer.gyp b/utils/dartanalyzer/dartanalyzer.gyp
index daf226cfb84..282d3042c78 100644
--- a/utils/dartanalyzer/dartanalyzer.gyp
+++ b/utils/dartanalyzer/dartanalyzer.gyp
@@ -16,8 +16,10 @@
           'inputs': [
             '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)dart<(EXECUTABLE_SUFFIX)',
             '../../sdk/lib/_internal/sdk_library_metadata/lib/libraries.dart',
-            '<!@(["python", "../../tools/list_files.py", "\\.dart$", "../../pkg/analyzer_cli"])',
-            '<!@(["python", "../../tools/list_files.py", "\\.dart$", "../../pkg/analyzer"])',
+            '<!@(["python", "../../tools/list_dart_files.py", "relative", '
+                '"../../pkg/analyzer_cli"])',
+            '<!@(["python", "../../tools/list_dart_files.py", "relative", '
+                '"../../pkg/analyzer"])',
           ],
           'outputs': [
             '<(SHARED_INTERMEDIATE_DIR)/dartanalyzer.dart.snapshot',
@@ -33,8 +35,10 @@
           'action_name': 'generate_summary_spec',
           'inputs': [
             '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)dart<(EXECUTABLE_SUFFIX)',
-            '<!@(["python", "../../tools/list_files.py", "\\.dart$", "../../sdk/lib"])',
-            '<!@(["python", "../../tools/list_files.py", "\\.dart$", "../../pkg/analyzer"])',
+            '<!@(["python", "../../tools/list_dart_files.py", "relative", '
+                '"../../sdk/lib"])',
+            '<!@(["python", "../../tools/list_dart_files.py", "relative", '
+                '"../../pkg/analyzer"])',
           ],
           'outputs': [
             '<(SHARED_INTERMEDIATE_DIR)/spec.sum',
@@ -51,8 +55,10 @@
           'action_name': 'generate_summary_strong',
           'inputs': [
             '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)dart<(EXECUTABLE_SUFFIX)',
-            '<!@(["python", "../../tools/list_files.py", "\\.dart$", "../../sdk/lib"])',
-            '<!@(["python", "../../tools/list_files.py", "\\.dart$", "../../pkg/analyzer"])',
+            '<!@(["python", "../../tools/list_dart_files.py", "relative", '
+                '"../../sdk/lib"])',
+            '<!@(["python", "../../tools/list_dart_files.py", "relative", '
+                '"../../pkg/analyzer"])',
           ],
           'outputs': [
             '<(SHARED_INTERMEDIATE_DIR)/strong.sum',
diff --git a/utils/dartdevc/BUILD.gn b/utils/dartdevc/BUILD.gn
index 0c934233c8a..ba51ab4eed2 100644
--- a/utils/dartdevc/BUILD.gn
+++ b/utils/dartdevc/BUILD.gn
@@ -14,6 +14,7 @@ application_snapshot("dartdevc") {
     "--help",
   ]
   inputs = exec_script("../../tools/list_dart_files.py",
-                       [ rebase_path("../../pkg/dev_compiler/bin") ],
+                       [ "absolute",
+                         rebase_path("../../pkg/dev_compiler/bin") ],
                        "list lines")
 }
diff --git a/utils/dartdevc/dartdevc.gyp b/utils/dartdevc/dartdevc.gyp
index 167327ec99d..b141bc5e590 100644
--- a/utils/dartdevc/dartdevc.gyp
+++ b/utils/dartdevc/dartdevc.gyp
@@ -16,7 +16,8 @@
           'inputs': [
             '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)dart<(EXECUTABLE_SUFFIX)',
             '../../sdk/lib/_internal/sdk_library_metadata/lib/libraries.dart',
-            '<!@(["python", "../../tools/list_files.py", "\\.dart$", "../../pkg/dev_compiler/bin"])',
+            '<!@(["python", "../../tools/list_dart_files.py", "relative", '
+                '"../../pkg/dev_compiler/bin"])',
             '<(SHARED_INTERMEDIATE_DIR)/pkg_files.stamp',
           ],
           'outputs': [
diff --git a/utils/dartdoc/BUILD.gn b/utils/dartdoc/BUILD.gn
index 6abdc9a1a71..ac302a821bc 100644
--- a/utils/dartdoc/BUILD.gn
+++ b/utils/dartdoc/BUILD.gn
@@ -8,6 +8,7 @@ application_snapshot("dartdoc") {
   main_dart = "../../third_party/pkg/dartdoc/bin/dartdoc.dart"
   training_args = [ "--help" ]
   inputs = exec_script("../../tools/list_dart_files.py",
-                       [ rebase_path("../../third_party/pkg/dartdoc") ],
+                       [ "absolute",
+                         rebase_path("../../third_party/pkg/dartdoc") ],
                        "list lines")
 }
diff --git a/utils/dartdoc/dartdoc.gyp b/utils/dartdoc/dartdoc.gyp
index dc5e414834c..e5327c0edc0 100644
--- a/utils/dartdoc/dartdoc.gyp
+++ b/utils/dartdoc/dartdoc.gyp
@@ -16,7 +16,8 @@
           'inputs': [
             '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)dart<(EXECUTABLE_SUFFIX)',
             '../../sdk/lib/_internal/sdk_library_metadata/lib/libraries.dart',
-            '<!@(["python", "../../tools/list_files.py", "\\.dart$", "../../third_party/pkg/dartdoc"])',
+            '<!@(["python", "../../tools/list_dart_files.py", "relative", '
+                '"../../third_party/pkg/dartdoc"])',
           ],
           'outputs': [
             '<(SHARED_INTERMEDIATE_DIR)/dartdoc.dart.snapshot',
@@ -31,4 +32,4 @@
       ],
     },
   ],
-}
\ No newline at end of file
+}
diff --git a/utils/dartfmt/BUILD.gn b/utils/dartfmt/BUILD.gn
index 41c5bc43066..7c688a318f6 100644
--- a/utils/dartfmt/BUILD.gn
+++ b/utils/dartfmt/BUILD.gn
@@ -9,6 +9,7 @@ application_snapshot("dartfmt") {
   training_args = [ "--help" ]
   inputs =
       exec_script("../../tools/list_dart_files.py",
-                  [ rebase_path("../../third_party/pkg_tested/dart_style") ],
+                  [ "absolute",
+                    rebase_path("../../third_party/pkg_tested/dart_style") ],
                   "list lines")
 }
diff --git a/utils/dartfmt/dartfmt.gyp b/utils/dartfmt/dartfmt.gyp
index a59ef9a5b02..5590883474b 100644
--- a/utils/dartfmt/dartfmt.gyp
+++ b/utils/dartfmt/dartfmt.gyp
@@ -16,7 +16,8 @@
           'inputs': [
             '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)dart<(EXECUTABLE_SUFFIX)',
             '../../sdk/lib/_internal/sdk_library_metadata/lib/libraries.dart',
-            '<!@(["python", "../../tools/list_files.py", "\\.dart$", "../../third_party/pkg_tested/dart_style"])',
+            '<!@(["python", "../../tools/list_dart_files.py", "relative", '
+                '"../../third_party/pkg_tested/dart_style"])',
           ],
           'outputs': [
             '<(SHARED_INTERMEDIATE_DIR)/dartfmt.dart.snapshot',