[tools] Flexible perf runner path.

Improved flexibility for the perf runner, by adding option to
specify precisely shell binary.

NOTRY=true

Review URL: https://codereview.chromium.org/1659483003

Cr-Commit-Position: refs/heads/master@{#33649}

tools/run_perf.py

@@ -350,9 +350,9 @@ class Node(object):
 
 class DefaultSentinel(Node):
   """Fake parent node with all default values."""
-  def __init__(self):
+  def __init__(self, binary = "d8"):
     super(DefaultSentinel, self).__init__()
-    self.binary = "d8"
+    self.binary = binary
     self.run_count = 10
     self.timeout = 60
     self.path = []
@@ -543,11 +543,10 @@ def MakeGraphConfig(suite, arch, parent):
     raise Exception("Invalid suite configuration.")
 
 
-def BuildGraphConfigs(suite, arch, parent=None):
+def BuildGraphConfigs(suite, arch, parent):
   """Builds a tree structure of graph objects that corresponds to the suite
   configuration.
   """
-  parent = parent or DefaultSentinel()
 
   # TODO(machenbach): Implement notion of cpu type?
   if arch not in suite.get("archs", SUPPORTED_ARCHS):
@@ -813,6 +812,11 @@ def Main(args):
                     default="out")
   parser.add_option("--outdir-no-patch",
                     help="Base directory with compile output without patch")
+  parser.add_option("--binary-override-path",
+                    help="JavaScript engine binary. By default, d8 under "
+                    "architecture-specific build dir. "
+                    "Not supported in conjunction with outdir-no-patch.")
+
   (options, args) = parser.parse_args(args)
 
   if len(args) == 0:  # pragma: no cover
@@ -843,7 +847,18 @@ def Main(args):
   else:
     build_config = "%s.release" % options.arch
 
-  options.shell_dir = os.path.join(workspace, options.outdir, build_config)
+  if options.binary_override_path == None:
+    options.shell_dir = os.path.join(workspace, options.outdir, build_config)
+    default_binary_name = "d8"
+  else:
+    if not os.path.isfile(options.binary_override_path):
+      print "binary-override-path must be a file name"
+      return 1
+    if options.outdir_no_patch:
+      print "specify either binary-override-path or outdir-no-patch"
+      return 1
+    options.shell_dir = os.path.dirname(options.binary_override_path)
+    default_binary_name = os.path.basename(options.binary_override_path)
 
   if options.outdir_no_patch:
     options.shell_dir_no_patch = os.path.join(
@@ -872,7 +887,8 @@ def Main(args):
     platform.PreExecution()
 
     # Build the graph/trace tree structure.
-    root = BuildGraphConfigs(suite, options.arch)
+    default_parent = DefaultSentinel(default_binary_name)
+    root = BuildGraphConfigs(suite, options.arch, default_parent)
 
     # Callback to be called on each node on traversal.
     def NodeCB(node):