[Compile perf] flake8 fixes for scale-test.

Author: graydon

utils/scale-test

@@ -12,23 +12,34 @@
 # values.
 #
 
-import gyb, os, os.path, shutil, subprocess
+import argparse
+import json
+import os
+import os.path
+import shutil
+import subprocess
+import sys
+import tempfile
+import gyb
+
 
 def find_which(p):
     for d in os.environ["PATH"].split(os.pathsep):
-        full = os.path.join(d,p)
+        full = os.path.join(d, p)
         if os.path.isfile(full) and os.access(full, os.X_OK):
             return full
     return p
 
+
 # Evidently the debug-symbol reader in dtrace is sufficiently slow and/or buggy
 # that attempting to inject probes into a binary w/ debuginfo is asking for a
 # failed run (possibly racing with probe insertion, or probing the stabs
 # entries, see rdar://problem/7037927 or rdar://problem/11490861 respectively),
 # so we sniff the presence of debug symbols here.
 def has_debuginfo(swiftc):
     swiftc = find_which(swiftc)
-    for line in subprocess.check_output(["dwarfdump", "--file-stats", swiftc]).splitlines():
+    for line in subprocess.check_output(
+            ["dwarfdump", "--file-stats", swiftc]).splitlines():
         if '%' not in line:
             continue
         fields = line.split()
@@ -40,16 +51,15 @@ def has_debuginfo(swiftc):
 def write_input_file(args, ast, d, n):
     fname = "in%d.swift" % n
     pathname = os.path.join(d, fname)
-    with open(pathname,'w+') as f:
+    with open(pathname, 'w+') as f:
         f.write(gyb.execute_template(ast, '', N=n))
     return fname
 
 
 def run_once_with_primary(args, ast, rng, primary_idx):
-    import sys, tempfile, json
     r = {}
     try:
-        if args.tmpdir != None and not os.path.exists(args.tmpdir):
+        if args.tmpdir is not None and not os.path.exists(args.tmpdir):
             os.makedirs(args.tmpdir, 0700)
         d = tempfile.mkdtemp(dir=args.tmpdir)
         inputs = [write_input_file(args, ast, d, i) for i in rng]
@@ -85,7 +95,8 @@ def run_once_with_primary(args, ast, rng, primary_idx):
 
         if args.dtrace:
             trace = "trace.txt"
-            script = "pid$target:swiftc:*%s*:entry { @[probefunc] = count() }" % args.select
+            script = ("pid$target:swiftc:*%s*:entry { @[probefunc] = count() }"
+                      % args.select)
             subprocess.check_call(
                 ["sudo", "dtrace", "-q",
                  "-o", trace,
@@ -108,7 +119,7 @@ def run_once_with_primary(args, ast, rng, primary_idx):
     finally:
         shutil.rmtree(d)
 
-    return {k:v for (k,v) in r.items() if args.select in k}
+    return {k: v for (k, v) in r.items() if args.select in k}
 
 
 def run_once(args, ast, rng):
@@ -125,6 +136,7 @@ def run_once(args, ast, rng):
     else:
         return run_once_with_primary(args, ast, rng, -1)
 
+
 def run_many(args):
 
     if args.dtrace and has_debuginfo(args.swiftc_binary):
@@ -148,25 +160,24 @@ def run_many(args):
 
 
 def linear_regression(x, y):
-   # By the book: https://en.wikipedia.org/wiki/Simple_linear_regression
-   n = len(x)
-   assert n == len(y)
-   if n == 0:
-       return 0, 0
-   prod_sum = 0
-   sum_x = sum(x)
-   sum_y = sum(y)
-   sum_prod = sum(a * b for a, b in zip(x, y))
-   sum_x_sq = sum(a ** 2 for a in x)
-   mean_x = sum_x/n
-   mean_y = sum_y/n
-   mean_prod = sum_prod/n
-   mean_x_sq = sum_x_sq/n
-   covar_xy = mean_prod - mean_x * mean_y
-   var_x = mean_x_sq - mean_x**2
-   slope = covar_xy / var_x
-   inter = mean_y - slope * mean_x
-   return slope, inter
+    # By the book: https://en.wikipedia.org/wiki/Simple_linear_regression
+    n = len(x)
+    assert n == len(y)
+    if n == 0:
+        return 0, 0
+    sum_x = sum(x)
+    sum_y = sum(y)
+    sum_prod = sum(a * b for a, b in zip(x, y))
+    sum_x_sq = sum(a ** 2 for a in x)
+    mean_x = sum_x/n
+    mean_y = sum_y/n
+    mean_prod = sum_prod/n
+    mean_x_sq = sum_x_sq/n
+    covar_xy = mean_prod - mean_x * mean_y
+    var_x = mean_x_sq - mean_x**2
+    slope = covar_xy / var_x
+    inter = mean_y - slope * mean_x
+    return slope, inter
 
 
 def report(args, rng, runs):
@@ -199,7 +210,6 @@ def report(args, rng, runs):
 
 
 def main():
-    import argparse, sys
     parser = argparse.ArgumentParser()
     parser.add_argument(
         'file', type=argparse.FileType(),
@@ -249,7 +259,7 @@ def main():
         default=None, help='directory to create tempfiles in')
     parser.add_argument(
         '--select',
-        default="", help='substring of counters/symbols to restrict attention to')
+        default="", help='substring of counters/symbols to limit attention to')
     parser.add_argument(
         '--debug', action='store_true',
         default=False, help='invoke lldb on each scale test')
@@ -279,5 +289,6 @@ def main():
         exit(1)
     exit(0)
 
+
 if __name__ == '__main__':
     main()