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Python: CG trace: Refactoring

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This commit is contained in:
Rasmus Wriedt Larsen
2020-07-21 19:53:05 +02:00
parent 290eb638f9
commit 58f11194a8
1 changed files with 13 additions and 9 deletions
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22
python/tools/recorded-call-graph-metrics/src/cg_trace/bytecode_reconstructor.py
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@@ -51,7 +51,7 @@ class BytecodeUnknown(BytecodeExpr):
return f"<{self.opname}>"
def find_inst_that_added_elem_to_stack(
def expr_that_added_elem_to_stack(
instructions: List[Instruction], start_index: int, stack_pos: int
):
"""Backwards traverse instructions
@@ -69,7 +69,8 @@ def find_inst_that_added_elem_to_stack(
We can look for the function that is called by invoking this function with
`start_index = 1` and `stack_pos = 1`. It will see that `LOAD_CONST` added the top
element to the stack, and find that `LOAD_GLOBAL` was the instruction to add element
in stack position 1 to the stack -- so the index 0 is returned.
in stack position 1 to the stack -- so `expr_from_instruction(instructions, 0)` is
returned.
It is assumed that if `stack_pos == 0` then the instruction you are looking for is
the one at `instructions[start_index]`. This might not hold, in case of using `NOP`
@@ -80,11 +81,16 @@ def find_inst_that_added_elem_to_stack(
for inst in reversed(instructions[: start_index + 1]):
if stack_pos == 0:
LOGGER.debug(f"Found it: {inst}")
return instructions.index(inst)
LOGGER.debug(f"Skipping {inst}")
found_index = instructions.index(inst)
break
old = stack_pos
stack_pos -= dis.stack_effect(inst.opcode, inst.arg)
new = stack_pos
LOGGER.debug(f"Skipping ({old} -> {new}) {inst}")
else:
raise Exception("inst_index_for_stack_diff failed")
raise Exception("inst_index_for_stack_diff failed")
return expr_from_instruction(instructions, found_index)
def expr_from_instruction(instructions: List[Instruction], index: int) -> BytecodeExpr:
@@ -99,8 +105,7 @@ def expr_from_instruction(instructions: List[Instruction], index: int) -> Byteco
# https://docs.python.org/3/library/dis.html#opcode-LOAD_ATTR
elif inst.opname in ["LOAD_METHOD", "LOAD_ATTR"]:
attr_name = inst.argval
obj_index = find_inst_that_added_elem_to_stack(instructions, index - 1, 0)
obj_expr = expr_from_instruction(instructions, obj_index)
obj_expr = expr_that_added_elem_to_stack(instructions, index - 1, 0)
return BytecodeAttribute(attr_name=attr_name, object=obj_expr)
# https://docs.python.org/3/library/dis.html#opcode-CALL_FUNCTION
@@ -112,10 +117,9 @@ def expr_from_instruction(instructions: List[Instruction], index: int) -> Byteco
elif inst.opname == "CALL_FUNCTION_KW":
num_stack_elems = inst.arg + 1
func_index = find_inst_that_added_elem_to_stack(
func_expr = expr_that_added_elem_to_stack(
instructions, index - 1, num_stack_elems
)
func_expr = expr_from_instruction(instructions, func_index)
return BytecodeCall(function=func_expr)
else: