[compiler-rt] r267126 - [ASAN] Use struct instead of array in sancov.py

[Sagar Thakur via llvm-commits]

Author: slthakur
Date: Fri Apr 22 04:20:22 2016
New Revision: 267126

URL: http://llvm.org/viewvc/llvm-project?rev=267126&view=rev
Log:
[ASAN] Use struct instead of array in sancov.py

Summary: When using 32-bit python with 64-bit asan the pc array in sancov.py cannot fit in 64-bit pc's because the type-code 'L' for
arrays in python corresponds to the C type long which is only of 4 bytes. Because of this some of the coverage tool tests fail on
mips. To fix these test possible solutions are to use 64-bit python or use struct.unpack with the 'Q' type-code. We have used
struct.unpack with 'Q' type code since it is not appropriate to have a 64-bit python on all hosts.

Reviewed by kcc, aizatsky

Differential: http://reviews.llvm.org/D18817

Modified:
    compiler-rt/trunk/lib/sanitizer_common/scripts/sancov.py

Modified: compiler-rt/trunk/lib/sanitizer_common/scripts/sancov.py
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/scripts/sancov.py?rev=267126&r1=267125&r2=267126&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/scripts/sancov.py (original)
+++ compiler-rt/trunk/lib/sanitizer_common/scripts/sancov.py Fri Apr 22 04:20:22 2016
@@ -30,6 +30,10 @@ def TypeCodeForBits(bits):
   CheckBits(bits)
   return 'L' if bits == 64 else 'I'
 
+def TypeCodeForStruct(bits):
+  CheckBits(bits)
+  return 'Q' if bits == 64 else 'I'
+
 kMagic32SecondHalf = 0xFFFFFF32;
 kMagic64SecondHalf = 0xFFFFFF64;
 kMagicFirstHalf    = 0xC0BFFFFF;
@@ -64,7 +68,7 @@ def ReadOneFile(path):
       raise Exception('File %s is short (< 8 bytes)' % path)
     bits = ReadMagicAndReturnBitness(f, path)
     size -= 8
-    s = array.array(TypeCodeForBits(bits), f.read(size))
+    s = struct.unpack_from(TypeCodeForStruct(bits) * (size * 8 / bits), f.read(size))
   print >>sys.stderr, "%s: read %d %d-bit PCs from %s" % (prog_name, size * 8 / bits, bits, path)
   return s
 
@@ -94,8 +98,8 @@ def MergeAndPrint(files):
   if max(s) > 0xFFFFFFFF:
     bits = 64
   array.array('I', MagicForBits(bits)).tofile(sys.stdout)
-  a = array.array(TypeCodeForBits(bits), s)
-  a.tofile(sys.stdout)
+  a = struct.pack(TypeCodeForStruct(bits) * len(s), *s)
+  sys.stdout.write(a)
 
 
 def UnpackOneFile(path):
@@ -148,7 +152,7 @@ def UnpackOneRawFile(path, map_path):
     f.seek(0, 2)
     size = f.tell()
     f.seek(0, 0)
-    pcs = array.array(TypeCodeForBits(bits), f.read(size))
+    pcs = struct.unpack_from(TypeCodeForStruct(bits) * (size * 8 / bits), f.read(size))
     mem_map_pcs = [[] for i in range(0, len(mem_map))]
 
     for pc in pcs:
@@ -166,11 +170,12 @@ def UnpackOneRawFile(path, map_path):
       assert path.endswith('.sancov.raw')
       dst_path = module_path + '.' + os.path.basename(path)[:-4]
       print >> sys.stderr, "%s: writing %d PCs to %s" % (prog_name, len(pc_list), dst_path)
-      arr = array.array(TypeCodeForBits(bits))
-      arr.fromlist(sorted(pc_list))
-      with open(dst_path, 'ab') as f2:
+      sorted_pc_list = sorted(pc_list)
+      pc_buffer = struct.pack(TypeCodeForStruct(bits) * len(pc_list), *sorted_pc_list)
+      with open(dst_path, 'ab+') as f2:
         array.array('I', MagicForBits(bits)).tofile(f2)
-        arr.tofile(f2)
+        f2.seek(0, 2)
+        f2.write(pc_buffer)
 
 def RawUnpack(files):
   for f in files: