[PATCH v8 6/7] fuzz: add minimization options

[Qiuhao Li]

-M1: remove IO commands iteratively
-M2: try setting bits in operand of write/out to zero

Signed-off-by: Qiuhao Li <Qiuhao.Li@outlook.com>
Reviewed-by: Alexander Bulekov <alxndr@bu.edu>
Tested-by: Alexander Bulekov <alxndr@bu.edu>
---
 scripts/oss-fuzz/minimize_qtest_trace.py | 30 ++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/scripts/oss-fuzz/minimize_qtest_trace.py 
b/scripts/oss-fuzz/minimize_qtest_trace.py
index 219858a9e3..0e59bdbb01 100755
--- a/scripts/oss-fuzz/minimize_qtest_trace.py
+++ b/scripts/oss-fuzz/minimize_qtest_trace.py
@@ -16,6 +16,10 @@ QEMU_PATH = None
 TIMEOUT = 5
 CRASH_TOKEN = None
 
+# Minimization levels
+M1 = False # try removing IO commands iteratively
+M2 = False # try setting bits in operand of write/out to zero
+
 write_suffix_lookup = {"b": (1, "B"),
                        "w": (2, "H"),
                        "l": (4, "L"),
@@ -23,10 +27,20 @@ write_suffix_lookup = {"b": (1, "B"),
 
 def usage():
     sys.exit("""\
-Usage: QEMU_PATH="/path/to/qemu" QEMU_ARGS="args" {} input_trace output_trace
+Usage:
+
+QEMU_PATH="/path/to/qemu" QEMU_ARGS="args" {} [Options] input_trace 
output_trace
+
 By default, will try to use the second-to-last line in the output to identify
 whether the crash occred. Optionally, manually set a string that idenitifes the
 crash by setting CRASH_TOKEN=
+
+Options:
+
+-M1: enable a loop around the remove minimizer, which may help decrease some
+     timing dependant instructions. Off by default.
+-M2: try setting bits in operand of write/out to zero. Off by default.
+
 """.format((sys.argv[0])))
 
 deduplication_note = """\n\
@@ -216,24 +230,32 @@ def minimize_trace(inpath, outpath):
     print("Setting the timeout for {} seconds".format(TIMEOUT))
 
     newtrace = trace[:]
+    global M1, M2
 
     # remove lines
     old_len = len(newtrace) + 1
     while(old_len > len(newtrace)):
         old_len = len(newtrace)
+        print("trace lenth = ", old_len)
         remove_lines(newtrace, outpath)
+        if not M1 and not M2:
+            break
         newtrace = list(filter(lambda s: s != "", newtrace))
     assert(check_if_trace_crashes(newtrace, outpath))
 
     # set bits to zero
-    clear_bits(newtrace, outpath)
+    if M2:
+        clear_bits(newtrace, outpath)
     assert(check_if_trace_crashes(newtrace, outpath))
 
 
 if __name__ == '__main__':
     if len(sys.argv) < 3:
         usage()
-
+    if "-M1" in sys.argv:
+        M1 = True
+    if "-M2" in sys.argv:
+        M2 = True
     QEMU_PATH = os.getenv("QEMU_PATH")
     QEMU_ARGS = os.getenv("QEMU_ARGS")
     if QEMU_PATH is None or QEMU_ARGS is None:
@@ -242,4 +264,4 @@ if __name__ == '__main__':
     #     QEMU_ARGS += " -accel qtest"
     CRASH_TOKEN = os.getenv("CRASH_TOKEN")
     QEMU_ARGS += " -qtest stdio -monitor none -serial none "
-    minimize_trace(sys.argv[1], sys.argv[2])
+    minimize_trace(sys.argv[-2], sys.argv[-1])
-- 
2.25.1