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| author | Ned Batchelder <ned@nedbatchelder.com> | 2009-04-02 19:42:04 -0400 |
|---|---|---|
| committer | Ned Batchelder <ned@nedbatchelder.com> | 2009-04-02 19:42:04 -0400 |
| commit | 4910434d33d0928374bf966c00c07feda5b32d77 (patch) | |
| tree | 7b8da0180a122d3b261ac19cffa4a6c6c1305507 /lab/hack_pyc.py | |
| parent | 1fadd547372a721a9b0acb4dc710195f85138c59 (diff) | |
| download | python-coveragepy-git-4910434d33d0928374bf966c00c07feda5b32d77.tar.gz | |
A lab directory for experiments in progress.
Diffstat (limited to 'lab/hack_pyc.py')
| -rw-r--r-- | lab/hack_pyc.py | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/lab/hack_pyc.py b/lab/hack_pyc.py new file mode 100644 index 00000000..e8992b96 --- /dev/null +++ b/lab/hack_pyc.py @@ -0,0 +1,82 @@ +""" Wicked hack to get .pyc files to do bytecode tracing instead of
+ line tracing.
+"""
+
+import marshal, new, opcode, sys, types
+
+from lnotab import lnotab_numbers, lnotab_string
+
+class PycFile:
+ def read(self, f):
+ if isinstance(f, basestring):
+ f = open(f, "rb")
+ self.magic = f.read(4)
+ self.modtime = f.read(4)
+ self.code = marshal.load(f)
+
+ def write(self, f):
+ if isinstance(f, basestring):
+ f = open(f, "wb")
+ f.write(self.magic)
+ f.write(self.modtime)
+ marshal.dump(self.code, f)
+
+ def hack_line_numbers(self):
+ self.code = hack_line_numbers(self.code)
+
+def hack_line_numbers(code):
+ """ Replace a code object's line number information to claim that every
+ byte of the bytecode is a new source line. Returns a new code
+ object. Also recurses to hack the line numbers in nested code objects.
+ """
+
+ # Create a new lnotab table. Each opcode is claimed to be at
+ # 1000*lineno + (opcode number within line), so for example, the opcodes on
+ # source line 12 will be given new line numbers 12000, 12001, 12002, etc.
+ old_num = list(lnotab_numbers(code.co_lnotab, code.co_firstlineno))
+ n_bytes = len(code.co_code)
+ new_num = []
+ line = 0
+ opnum_in_line = 0
+ i_byte = 0
+ while i_byte < n_bytes:
+ if old_num and i_byte == old_num[0][0]:
+ line = old_num.pop(0)[1]
+ opnum_in_line = 0
+ new_num.append((i_byte, 100000000 + 1000*line + opnum_in_line))
+ if ord(code.co_code[i_byte]) >= opcode.HAVE_ARGUMENT:
+ i_byte += 3
+ else:
+ i_byte += 1
+ opnum_in_line += 1
+
+ # new_num is a list of pairs, (byteoff, lineoff). Turn it into an lnotab.
+ new_firstlineno = new_num[0][1]-1
+ new_lnotab = lnotab_string(new_num, new_firstlineno)
+
+ # Recurse into code constants in this code object.
+ new_consts = []
+ for const in code.co_consts:
+ if type(const) == types.CodeType:
+ new_consts.append(hack_line_numbers(const))
+ else:
+ new_consts.append(const)
+
+ # Create a new code object, just like the old one, except with new
+ # line numbers.
+ new_code = new.code(
+ code.co_argcount, code.co_nlocals, code.co_stacksize, code.co_flags,
+ code.co_code, tuple(new_consts), code.co_names, code.co_varnames,
+ code.co_filename, code.co_name, new_firstlineno, new_lnotab
+ )
+
+ return new_code
+
+def hack_file(f):
+ pyc = PycFile()
+ pyc.read(f)
+ pyc.hack_line_numbers()
+ pyc.write(f)
+
+if __name__ == '__main__':
+ hack_file(sys.argv[1])
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