27 Commits

Author SHA1 Message Date
8c2196c05c bump version
Signed-off-by: varun-r-mallya <varunrmallya@gmail.com>
2025-09-26 22:48:17 +05:30
a2f86d680d Merge pull request #4 from varun-r-mallya/type_system
Type system and strings
2025-09-26 18:27:10 +05:30
0f365be65e Add some support for strings in structs 2025-09-26 18:26:07 +05:30
4ebf0480dd tweak commit to add placeholder string 2025-09-26 04:54:01 +05:30
b9ddecd6b1 Add string as a primitve to struct defs 2025-09-26 04:44:38 +05:30
737c4d3039 Support storing and printing string type 2025-09-26 04:17:29 +05:30
da8a495da7 Fix handle_cond for new symtab convention 2025-09-26 04:05:37 +05:30
ee03ac04d0 Fix printk handler to comply with new symtab convention 2025-09-26 01:02:10 +05:30
51595f9ec2 Add types returns to bpf helpers 2025-09-26 00:28:10 +05:30
4cf284a81f provide type as weel in eval_expr 2025-09-26 00:24:10 +05:30
1517f6e052 Fix local_sym_tab accesses in expr_pass 2025-09-25 23:54:04 +05:30
95f360059b Fix local_sym_tab accesses in binary_ops 2025-09-25 23:53:04 +05:30
dad57bd340 Fix local_sym_tab accesses in bpf_helper_handler 2025-09-25 23:51:08 +05:30
529b0bde19 Fix local_sym_tab accesses in functions_pass 2025-09-25 23:49:28 +05:30
943697ac9f Pass down type info in local_sym_tab 2025-09-25 23:43:19 +05:30
ba90af9ff2 Allocate space for string consts 2025-09-25 22:24:55 +05:30
35969c4ff7 Add string example 2025-09-25 22:15:14 +05:30
9e87ee52f2 Move relevant vmlinux files to ex7.bpf.c 2025-09-25 00:10:39 +05:30
d0be8893eb Add setuid C example 2025-09-24 23:48:42 +05:30
dda05bd044 Add matplotlib example 2025-09-23 20:36:15 +05:30
28e6f97708 add support for compilation with pylibbpf
Signed-off-by: varun-r-mallya <varunrmallya@gmail.com>
2025-09-21 18:05:43 +05:30
a1bc813ec5 Small fix to enum va 2025-09-21 17:58:51 +05:30
fefd6840c8 finish perf_event_output helper integration 2025-09-21 17:50:58 +05:30
79f0949abc Fix calling conventions changed by structs 2025-09-21 16:19:12 +05:30
a1371697cc overhaul handle_helper_calls 2025-09-21 16:10:29 +05:30
3c976b88d3 pass down structs_sym_tab 2025-09-21 15:20:41 +05:30
69a86c2433 Add perf_event_output boilerplate 2025-09-21 15:14:55 +05:30
12 changed files with 403 additions and 79 deletions

56
demo/pybpf4.py Normal file
View File

@ -0,0 +1,56 @@
import time
from pythonbpf import bpf, map, section, bpfglobal, BPF
from pythonbpf.helpers import pid
from pythonbpf.maps import HashMap
from pylibbpf import *
from ctypes import c_void_p, c_int64, c_uint64, c_int32
import matplotlib.pyplot as plt
# This program attaches an eBPF tracepoint to sys_enter_clone,
# counts per-PID clone syscalls, stores them in a hash map,
# and then plots the distribution as a histogram using matplotlib.
# It provides a quick view of process creation activity over 10 seconds.
# Everything is done with Python only code and with the new pylibbpf library.
# Run `sudo /path/to/python/binary/ pybpf4.py`
@bpf
@map
def hist() -> HashMap:
return HashMap(key=c_int32, value=c_uint64, max_entries=4096)
@bpf
@section("tracepoint/syscalls/sys_enter_clone")
def hello(ctx: c_void_p) -> c_int64:
process_id = pid()
one = 1
prev = hist().lookup(process_id)
if prev:
previous_value = prev + 1
print(f"count: {previous_value} with {process_id}")
hist().update(process_id, previous_value)
return c_int64(0)
else:
hist().update(process_id, one)
return c_int64(0)
@bpf
@bpfglobal
def LICENSE() -> str:
return "GPL"
b = BPF()
b.load_and_attach()
hist = BpfMap(b, hist)
print("Recording")
time.sleep(10)
counts = list(hist.values())
plt.hist(counts, bins=20)
plt.xlabel("Clone calls per PID")
plt.ylabel("Frequency")
plt.title("Syscall clone counts")
plt.show()

47
examples/c-form/ex7.bpf.c Normal file
View File

@ -0,0 +1,47 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
struct trace_entry {
short unsigned int type;
unsigned char flags;
unsigned char preempt_count;
int pid;
};
struct trace_event_raw_sys_enter {
struct trace_entry ent;
long int id;
long unsigned int args[6];
char __data[0];
};
struct event {
__u32 pid;
__u32 uid;
__u64 ts;
};
struct {
__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
} events SEC(".maps");
SEC("tp/syscalls/sys_enter_setuid")
int handle_setuid_entry(struct trace_event_raw_sys_enter *ctx) {
struct event data = {};
// Extract UID from the syscall arguments
data.uid = (unsigned int)ctx->args[0];
data.ts = bpf_ktime_get_ns();
data.pid = bpf_get_current_pid_tgid() >> 32;
bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU, &data, sizeof(data));
return 0;
}
char LICENSE[] SEC("license") = "GPL";

View File

@ -10,6 +10,7 @@ from ctypes import c_void_p, c_int64, c_int32, c_uint64
class data_t:
pid: c_uint64
ts: c_uint64
comm: str(16)
@bpf
@ -24,9 +25,12 @@ def hello(ctx: c_void_p) -> c_int32:
dataobj = data_t()
ts = ktime()
process_id = pid()
strobj = "hellohellohello"
dataobj.pid = process_id
dataobj.ts = ts
print(f"clone called at {ts} by pid {process_id}")
# dataobj.comm = strobj
print(f"clone called at {ts} by pid {process_id}, comm {strobj}")
events.output(dataobj)
return c_int32(0)

View File

@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
[project]
name = "pythonbpf"
version = "0.1.2"
version = "0.1.3"
description = "Reduced Python frontend for eBPF"
authors = [
{ name = "r41k0u", email="pragyanshchaturvedi18@gmail.com" },
@ -16,7 +16,8 @@ requires-python = ">=3.8"
dependencies = [
"llvmlite",
"astpretty"
"astpretty",
"pylibbpf"
]
[tool.setuptools.packages.find]

View File

@ -1,2 +1,2 @@
from .decorators import bpf, map, section, bpfglobal, struct
from .codegen import compile_to_ir, compile
from .codegen import compile_to_ir, compile, BPF

View File

@ -15,6 +15,7 @@ def recursive_dereferencer(var, builder):
else:
raise TypeError(f"Unsupported type for dereferencing: {var.type}")
def handle_binary_op(rval, module, builder, var_name, local_sym_tab, map_sym_tab, func):
print(module)
left = rval.left
@ -24,7 +25,7 @@ def handle_binary_op(rval, module, builder, var_name, local_sym_tab, map_sym_tab
# Handle left operand
if isinstance(left, ast.Name):
if left.id in local_sym_tab:
left = recursive_dereferencer(local_sym_tab[left.id], builder)
left = recursive_dereferencer(local_sym_tab[left.id][0], builder)
else:
raise SyntaxError(f"Undefined variable: {left.id}")
elif isinstance(left, ast.Constant):
@ -34,7 +35,7 @@ def handle_binary_op(rval, module, builder, var_name, local_sym_tab, map_sym_tab
if isinstance(right, ast.Name):
if right.id in local_sym_tab:
right = recursive_dereferencer(local_sym_tab[right.id], builder)
right = recursive_dereferencer(local_sym_tab[right.id][0], builder)
else:
raise SyntaxError(f"Undefined variable: {right.id}")
elif isinstance(right, ast.Constant):
@ -46,36 +47,36 @@ def handle_binary_op(rval, module, builder, var_name, local_sym_tab, map_sym_tab
if isinstance(op, ast.Add):
builder.store(builder.add(left, right),
local_sym_tab[var_name])
local_sym_tab[var_name][0])
elif isinstance(op, ast.Sub):
builder.store(builder.sub(left, right),
local_sym_tab[var_name])
local_sym_tab[var_name][0])
elif isinstance(op, ast.Mult):
builder.store(builder.mul(left, right),
local_sym_tab[var_name])
local_sym_tab[var_name][0])
elif isinstance(op, ast.Div):
builder.store(builder.sdiv(left, right),
local_sym_tab[var_name])
local_sym_tab[var_name][0])
elif isinstance(op, ast.Mod):
builder.store(builder.srem(left, right),
local_sym_tab[var_name])
local_sym_tab[var_name][0])
elif isinstance(op, ast.LShift):
builder.store(builder.shl(left, right),
local_sym_tab[var_name])
local_sym_tab[var_name][0])
elif isinstance(op, ast.RShift):
builder.store(builder.lshr(left, right),
local_sym_tab[var_name])
local_sym_tab[var_name][0])
elif isinstance(op, ast.BitOr):
builder.store(builder.or_(left, right),
local_sym_tab[var_name])
local_sym_tab[var_name][0])
elif isinstance(op, ast.BitXor):
builder.store(builder.xor(left, right),
local_sym_tab[var_name])
local_sym_tab[var_name][0])
elif isinstance(op, ast.BitAnd):
builder.store(builder.and_(left, right),
local_sym_tab[var_name])
local_sym_tab[var_name][0])
elif isinstance(op, ast.FloorDiv):
builder.store(builder.udiv(left, right),
local_sym_tab[var_name])
local_sym_tab[var_name][0])
else:
raise SyntaxError("Unsupported binary operation")

View File

@ -3,7 +3,7 @@ from llvmlite import ir
from .expr_pass import eval_expr
def bpf_ktime_get_ns_emitter(call, map_ptr, module, builder, func, local_sym_tab=None):
def bpf_ktime_get_ns_emitter(call, map_ptr, module, builder, func, local_sym_tab=None, local_var_metadata=None):
"""
Emit LLVM IR for bpf_ktime_get_ns helper function call.
"""
@ -13,10 +13,10 @@ def bpf_ktime_get_ns_emitter(call, map_ptr, module, builder, func, local_sym_tab
fn_ptr_type = ir.PointerType(fn_type)
fn_ptr = builder.inttoptr(helper_id, fn_ptr_type)
result = builder.call(fn_ptr, [], tail=False)
return result
return result, ir.IntType(64)
def bpf_map_lookup_elem_emitter(call, map_ptr, module, builder, local_sym_tab=None):
def bpf_map_lookup_elem_emitter(call, map_ptr, module, builder, func, local_sym_tab=None, struct_sym_tab=None, local_var_metadata=None):
"""
Emit LLVM IR for bpf_map_lookup_elem helper function call.
"""
@ -27,7 +27,7 @@ def bpf_map_lookup_elem_emitter(call, map_ptr, module, builder, local_sym_tab=No
if isinstance(key_arg, ast.Name):
key_name = key_arg.id
if local_sym_tab and key_name in local_sym_tab:
key_ptr = local_sym_tab[key_name]
key_ptr = local_sym_tab[key_name][0]
else:
raise ValueError(
f"Key variable {key_name} not found in local symbol table.")
@ -60,10 +60,10 @@ def bpf_map_lookup_elem_emitter(call, map_ptr, module, builder, local_sym_tab=No
result = builder.call(fn_ptr, [map_void_ptr, key_ptr], tail=False)
return result
return result, ir.PointerType()
def bpf_printk_emitter(call, map_ptr, module, builder, func, local_sym_tab=None):
def bpf_printk_emitter(call, map_ptr, module, builder, func, local_sym_tab=None, local_var_metadata=None):
if not hasattr(func, "_fmt_counter"):
func._fmt_counter = 0
@ -75,6 +75,7 @@ def bpf_printk_emitter(call, map_ptr, module, builder, func, local_sym_tab=None)
exprs = []
for value in call.args[0].values:
print("Value in f-string:", ast.dump(value))
if isinstance(value, ast.Constant):
if isinstance(value.value, str):
fmt_parts.append(value.value)
@ -85,10 +86,25 @@ def bpf_printk_emitter(call, map_ptr, module, builder, func, local_sym_tab=None)
raise NotImplementedError(
"Only string and integer constants are supported in f-string.")
elif isinstance(value, ast.FormattedValue):
# Assume int for now
fmt_parts.append("%lld")
print("Formatted value:", ast.dump(value))
# TODO: Dirty handling here, only checks for int or str
if isinstance(value.value, ast.Name):
exprs.append(value.value)
if local_sym_tab and value.value.id in local_sym_tab:
var_ptr, var_type = local_sym_tab[value.value.id]
if isinstance(var_type, ir.IntType):
fmt_parts.append("%lld")
exprs.append(value.value)
elif var_type == ir.PointerType(ir.IntType(8)):
# Case with string
fmt_parts.append("%s")
exprs.append(value.value)
else:
raise NotImplementedError(
"Only integer and pointer types are supported in formatted values.")
print("Formatted value variable:", var_ptr, var_type)
else:
raise ValueError(
f"Variable {value.value.id} not found in local symbol table.")
else:
raise NotImplementedError(
"Only simple variable names are supported in formatted values.")
@ -120,7 +136,8 @@ def bpf_printk_emitter(call, map_ptr, module, builder, func, local_sym_tab=None)
"Warning: bpf_printk supports up to 3 arguments, extra arguments will be ignored.")
for expr in exprs[:3]:
val = eval_expr(func, module, builder, expr, local_sym_tab, None)
val, _ = eval_expr(func, module, builder,
expr, local_sym_tab, None)
if val:
if isinstance(val.type, ir.PointerType):
val = builder.ptrtoint(val, ir.IntType(64))
@ -136,7 +153,6 @@ def bpf_printk_emitter(call, map_ptr, module, builder, func, local_sym_tab=None)
print(
"Warning: Failed to evaluate expression for bpf_printk argument. It will be converted to 0.")
args.append(ir.Constant(ir.IntType(64), 0))
fn_type = ir.FunctionType(ir.IntType(
64), [ir.PointerType(), ir.IntType(32)], var_arg=True)
fn_ptr_type = ir.PointerType(fn_type)
@ -172,7 +188,7 @@ def bpf_printk_emitter(call, map_ptr, module, builder, func, local_sym_tab=None)
ir.IntType(32), len(fmt_str))], tail=True)
def bpf_map_update_elem_emitter(call, map_ptr, module, builder, local_sym_tab=None):
def bpf_map_update_elem_emitter(call, map_ptr, module, builder, func, local_sym_tab=None, struct_sym_tab=None, local_var_metadata=None):
"""
Emit LLVM IR for bpf_map_update_elem helper function call.
Expected call signature: map.update(key, value, flags=0)
@ -189,7 +205,7 @@ def bpf_map_update_elem_emitter(call, map_ptr, module, builder, local_sym_tab=No
if isinstance(key_arg, ast.Name):
key_name = key_arg.id
if local_sym_tab and key_name in local_sym_tab:
key_ptr = local_sym_tab[key_name]
key_ptr = local_sym_tab[key_name][0]
else:
raise ValueError(
f"Key variable {key_name} not found in local symbol table.")
@ -208,7 +224,7 @@ def bpf_map_update_elem_emitter(call, map_ptr, module, builder, local_sym_tab=No
if isinstance(value_arg, ast.Name):
value_name = value_arg.id
if local_sym_tab and value_name in local_sym_tab:
value_ptr = local_sym_tab[value_name]
value_ptr = local_sym_tab[value_name][0]
else:
raise ValueError(
f"Value variable {value_name} not found in local symbol table.")
@ -231,7 +247,7 @@ def bpf_map_update_elem_emitter(call, map_ptr, module, builder, local_sym_tab=No
flags_name = flags_arg.id
if local_sym_tab and flags_name in local_sym_tab:
# Assume it's a stored integer value, load it
flags_ptr = local_sym_tab[flags_name]
flags_ptr = local_sym_tab[flags_name][0]
flags_val = builder.load(flags_ptr)
else:
raise ValueError(
@ -265,10 +281,10 @@ def bpf_map_update_elem_emitter(call, map_ptr, module, builder, local_sym_tab=No
result = builder.call(
fn_ptr, [map_void_ptr, key_ptr, value_ptr, flags_const], tail=False)
return result
return result, None
def bpf_map_delete_elem_emitter(call, map_ptr, module, builder, local_sym_tab=None):
def bpf_map_delete_elem_emitter(call, map_ptr, module, builder, func, local_sym_tab=None, struct_sym_tab=None, local_var_metadata=None):
"""
Emit LLVM IR for bpf_map_delete_elem helper function call.
Expected call signature: map.delete(key)
@ -284,7 +300,7 @@ def bpf_map_delete_elem_emitter(call, map_ptr, module, builder, local_sym_tab=No
if isinstance(key_arg, ast.Name):
key_name = key_arg.id
if local_sym_tab and key_name in local_sym_tab:
key_ptr = local_sym_tab[key_name]
key_ptr = local_sym_tab[key_name][0]
else:
raise ValueError(
f"Key variable {key_name} not found in local symbol table.")
@ -320,10 +336,10 @@ def bpf_map_delete_elem_emitter(call, map_ptr, module, builder, local_sym_tab=No
# Call the helper function
result = builder.call(fn_ptr, [map_void_ptr, key_ptr], tail=False)
return result
return result, None
def bpf_get_current_pid_tgid_emitter(call, map_ptr, module, builder, func, local_sym_tab=None):
def bpf_get_current_pid_tgid_emitter(call, map_ptr, module, builder, func, local_sym_tab=None, local_var_metadata=None):
"""
Emit LLVM IR for bpf_get_current_pid_tgid helper function call.
"""
@ -337,7 +353,59 @@ def bpf_get_current_pid_tgid_emitter(call, map_ptr, module, builder, func, local
# Extract the lower 32 bits (PID) using bitwise AND with 0xFFFFFFFF
mask = ir.Constant(ir.IntType(64), 0xFFFFFFFF)
pid = builder.and_(result, mask)
return pid
return pid, ir.IntType(64)
def bpf_perf_event_output_handler(call, map_ptr, module, builder, func, local_sym_tab=None, struct_sym_tab=None, local_var_metadata=None):
if len(call.args) != 1:
raise ValueError("Perf event output expects exactly one argument (data), got "
f"{len(call.args)}")
data_arg = call.args[0]
ctx_ptr = func.args[0] # First argument to the function is ctx
if isinstance(data_arg, ast.Name):
data_name = data_arg.id
if local_sym_tab and data_name in local_sym_tab:
data_ptr = local_sym_tab[data_name][0]
else:
raise ValueError(
f"Data variable {data_name} not found in local symbol table.")
# Check is data_name is a struct
if local_var_metadata and data_name in local_var_metadata:
data_type = local_var_metadata[data_name]
if data_type in struct_sym_tab:
struct_info = struct_sym_tab[data_type]
size_val = ir.Constant(ir.IntType(64), struct_info["size"])
else:
raise ValueError(
f"Struct type {data_type} for variable {data_name} not found in struct symbol table.")
else:
raise ValueError(
f"Metadata for variable {data_name} not found in local variable metadata.")
# BPF_F_CURRENT_CPU is -1 in 32 bit
flags_val = ir.Constant(ir.IntType(64), 0xFFFFFFFF)
map_void_ptr = builder.bitcast(map_ptr, ir.PointerType())
data_void_ptr = builder.bitcast(data_ptr, ir.PointerType())
fn_type = ir.FunctionType(
ir.IntType(64),
[ir.PointerType(ir.IntType(8)), ir.PointerType(), ir.IntType(64),
ir.PointerType(), ir.IntType(64)],
var_arg=False
)
fn_ptr_type = ir.PointerType(fn_type)
# helper id
fn_addr = ir.Constant(ir.IntType(64), 25)
fn_ptr = builder.inttoptr(fn_addr, fn_ptr_type)
result = builder.call(
fn_ptr, [ctx_ptr, map_void_ptr, flags_val, data_void_ptr, size_val], tail=False)
return result, None
else:
raise NotImplementedError(
"Only simple object names are supported as data in perf event output.")
helper_func_list = {
@ -347,10 +415,11 @@ helper_func_list = {
"update": bpf_map_update_elem_emitter,
"delete": bpf_map_delete_elem_emitter,
"pid": bpf_get_current_pid_tgid_emitter,
"output": bpf_perf_event_output_handler,
}
def handle_helper_call(call, module, builder, func, local_sym_tab=None, map_sym_tab=None):
def handle_helper_call(call, module, builder, func, local_sym_tab=None, map_sym_tab=None, struct_sym_tab=None, local_var_metadata=None):
if isinstance(call.func, ast.Name):
func_name = call.func.id
if func_name in helper_func_list:
@ -367,14 +436,29 @@ def handle_helper_call(call, module, builder, func, local_sym_tab=None, map_sym_
if map_sym_tab and map_name in map_sym_tab:
map_ptr = map_sym_tab[map_name]
if method_name in helper_func_list:
print(local_var_metadata)
return helper_func_list[method_name](
call, map_ptr, module, builder, local_sym_tab)
call, map_ptr, module, builder, func, local_sym_tab, struct_sym_tab, local_var_metadata)
else:
raise NotImplementedError(
f"Map method {method_name} is not implemented as a helper function.")
else:
raise ValueError(
f"Map variable {map_name} not found in symbol tables.")
elif isinstance(call.func.value, ast.Name):
obj_name = call.func.value.id
method_name = call.func.attr
if map_sym_tab and obj_name in map_sym_tab:
map_ptr = map_sym_tab[obj_name]
if method_name in helper_func_list:
return helper_func_list[method_name](
call, map_ptr, module, builder, func, local_sym_tab, struct_sym_tab, local_var_metadata)
else:
raise NotImplementedError(
f"Map method {method_name} is not implemented as a helper function.")
else:
raise ValueError(
f"Map variable {obj_name} not found in symbol tables.")
else:
raise NotImplementedError(
"Attribute not supported for map method calls.")

View File

@ -9,6 +9,7 @@ import os
import subprocess
import inspect
from pathlib import Path
from pylibbpf import BpfProgram
def find_bpf_chunks(tree):
@ -92,6 +93,7 @@ def compile_to_ir(filename: str, output: str):
module.add_named_metadata("llvm.ident", ["llvmlite PythonBPF v0.0.1"])
print(f"IR written to {output}")
with open(output, "w") as f:
f.write(f"source_filename = \"{filename}\"\n")
f.write(str(module))
@ -116,3 +118,18 @@ def compile():
], check=True)
print(f"Object written to {o_file}, {ll_file} can be removed")
def BPF() -> BpfProgram:
caller_frame = inspect.stack()[1]
caller_file = Path(caller_frame.filename).resolve()
ll_file = Path("/tmp") / caller_file.with_suffix(".ll").name
o_file = Path("/tmp") / caller_file.with_suffix(".o").name
compile_to_ir(str(caller_file), str(ll_file))
subprocess.run([
"llc", "-march=bpf", "-filetype=obj", "-O2",
str(ll_file), "-o", str(o_file)
], check=True)
return BpfProgram(str(o_file))

View File

@ -2,21 +2,21 @@ import ast
from llvmlite import ir
def eval_expr(func, module, builder, expr, local_sym_tab, map_sym_tab):
print(f"Evaluating expression: {expr}")
def eval_expr(func, module, builder, expr, local_sym_tab, map_sym_tab, structs_sym_tab=None, local_var_metadata=None):
print(f"Evaluating expression: {ast.dump(expr)}")
if isinstance(expr, ast.Name):
if expr.id in local_sym_tab:
var = local_sym_tab[expr.id]
var = local_sym_tab[expr.id][0]
val = builder.load(var)
return val
return val, local_sym_tab[expr.id][1] # return value and type
else:
print(f"Undefined variable {expr.id}")
return None
elif isinstance(expr, ast.Constant):
if isinstance(expr.value, int):
return ir.Constant(ir.IntType(64), expr.value)
return ir.Constant(ir.IntType(64), expr.value), ir.IntType(64)
elif isinstance(expr.value, bool):
return ir.Constant(ir.IntType(1), int(expr.value))
return ir.Constant(ir.IntType(1), int(expr.value)), ir.IntType(1)
else:
print("Unsupported constant type")
return None
@ -37,35 +37,45 @@ def eval_expr(func, module, builder, expr, local_sym_tab, map_sym_tab):
return None
if isinstance(arg, ast.Name):
if arg.id in local_sym_tab:
arg = local_sym_tab[arg.id]
arg = local_sym_tab[arg.id][0]
else:
print(f"Undefined variable {arg.id}")
return None
if arg is None:
print("Failed to evaluate deref argument")
return None
# Since we are handling only name case, directly take type from sym tab
val = builder.load(arg)
return val
return val, local_sym_tab[expr.args[0].id][1]
# check for helpers
if expr.func.id in helper_func_list:
return handle_helper_call(
expr, module, builder, func, local_sym_tab, map_sym_tab)
expr, module, builder, func, local_sym_tab, map_sym_tab, structs_sym_tab, local_var_metadata)
elif isinstance(expr.func, ast.Attribute):
print(f"Handling method call: {ast.dump(expr.func)}")
if isinstance(expr.func.value, ast.Call) and isinstance(expr.func.value.func, ast.Name):
method_name = expr.func.attr
if method_name in helper_func_list:
return handle_helper_call(
expr, module, builder, func, local_sym_tab, map_sym_tab)
expr, module, builder, func, local_sym_tab, map_sym_tab, structs_sym_tab, local_var_metadata)
elif isinstance(expr.func.value, ast.Name):
obj_name = expr.func.value.id
method_name = expr.func.attr
if obj_name in map_sym_tab:
if method_name in helper_func_list:
return handle_helper_call(
expr, module, builder, func, local_sym_tab, map_sym_tab, structs_sym_tab, local_var_metadata)
print("Unsupported expression evaluation")
return None
def handle_expr(func, module, builder, expr, local_sym_tab, map_sym_tab):
def handle_expr(func, module, builder, expr, local_sym_tab, map_sym_tab, structs_sym_tab, local_var_metadata):
"""Handle expression statements in the function body."""
print(f"Handling expression: {ast.dump(expr)}")
call = expr.value
if isinstance(call, ast.Call):
eval_expr(func, module, builder, call, local_sym_tab, map_sym_tab)
eval_expr(func, module, builder, call, local_sym_tab,
map_sym_tab, structs_sym_tab, local_var_metadata)
else:
print("Unsupported expression type")

View File

@ -51,36 +51,57 @@ def handle_assign(func, module, builder, stmt, map_sym_tab, local_sym_tab, struc
if field_name in struct_info["fields"]:
field_idx = struct_info["fields"][field_name]
struct_ptr = local_sym_tab[var_name]
struct_ptr = local_sym_tab[var_name][0]
field_ptr = builder.gep(
struct_ptr, [ir.Constant(ir.IntType(32), 0),
ir.Constant(ir.IntType(32), field_idx)],
inbounds=True)
val = eval_expr(func, module, builder, rval,
local_sym_tab, map_sym_tab)
local_sym_tab, map_sym_tab, structs_sym_tab)
if isinstance(struct_info["field_types"][field_idx], ir.ArrayType) and val[1] == ir.PointerType(ir.IntType(8)):
# TODO: Figure it out, not a priority rn
# Special case for string assignment to char array
#str_len = struct_info["field_types"][field_idx].count
#assign_string_to_array(builder, field_ptr, val[0], str_len)
#print(f"Assigned to struct field {var_name}.{field_name}")
pass
if val is None:
print("Failed to evaluate struct field assignment")
return
builder.store(val, field_ptr)
print(field_ptr)
builder.store(val[0], field_ptr)
print(f"Assigned to struct field {var_name}.{field_name}")
return
elif isinstance(rval, ast.Constant):
if isinstance(rval.value, bool):
if rval.value:
builder.store(ir.Constant(ir.IntType(1), 1),
local_sym_tab[var_name])
local_sym_tab[var_name][0])
else:
builder.store(ir.Constant(ir.IntType(1), 0),
local_sym_tab[var_name])
local_sym_tab[var_name][0])
print(f"Assigned constant {rval.value} to {var_name}")
elif isinstance(rval.value, int):
# Assume c_int64 for now
# var = builder.alloca(ir.IntType(64), name=var_name)
# var.align = 8
builder.store(ir.Constant(ir.IntType(64), rval.value),
local_sym_tab[var_name])
local_sym_tab[var_name][0])
# local_sym_tab[var_name] = var
print(f"Assigned constant {rval.value} to {var_name}")
elif isinstance(rval.value, str):
str_val = rval.value.encode('utf-8') + b'\x00'
str_const = ir.Constant(ir.ArrayType(
ir.IntType(8), len(str_val)), bytearray(str_val))
global_str = ir.GlobalVariable(
module, str_const.type, name=f"{var_name}_str")
global_str.linkage = 'internal'
global_str.global_constant = True
global_str.initializer = str_const
str_ptr = builder.bitcast(
global_str, ir.PointerType(ir.IntType(8)))
builder.store(str_ptr, local_sym_tab[var_name][0])
print(f"Assigned string constant '{rval.value}' to {var_name}")
else:
print("Unsupported constant type")
elif isinstance(rval, ast.Call):
@ -92,7 +113,7 @@ def handle_assign(func, module, builder, stmt, map_sym_tab, local_sym_tab, struc
# var = builder.alloca(ir_type, name=var_name)
# var.align = ir_type.width // 8
builder.store(ir.Constant(
ir_type, rval.args[0].value), local_sym_tab[var_name])
ir_type, rval.args[0].value), local_sym_tab[var_name][0])
print(f"Assigned {call_type} constant "
f"{rval.args[0].value} to {var_name}")
# local_sym_tab[var_name] = var
@ -100,19 +121,19 @@ def handle_assign(func, module, builder, stmt, map_sym_tab, local_sym_tab, struc
# var = builder.alloca(ir.IntType(64), name=var_name)
# var.align = 8
val = handle_helper_call(
rval, module, builder, None, local_sym_tab, map_sym_tab)
builder.store(val, local_sym_tab[var_name])
rval, module, builder, func, local_sym_tab, map_sym_tab, structs_sym_tab, local_var_metadata)
builder.store(val[0], local_sym_tab[var_name][0])
# local_sym_tab[var_name] = var
print(f"Assigned constant {rval.func.id} to {var_name}")
elif call_type == "deref" and len(rval.args) == 1:
print(f"Handling deref assignment {ast.dump(rval)}")
val = eval_expr(func, module, builder, rval,
local_sym_tab, map_sym_tab)
local_sym_tab, map_sym_tab, structs_sym_tab)
if val is None:
print("Failed to evaluate deref argument")
return
print(f"Dereferenced value: {val}, storing in {var_name}")
builder.store(val, local_sym_tab[var_name])
builder.store(val[0], local_sym_tab[var_name][0])
# local_sym_tab[var_name] = var
print(f"Dereferenced and assigned to {var_name}")
elif call_type in structs_sym_tab and len(rval.args) == 0:
@ -121,7 +142,7 @@ def handle_assign(func, module, builder, stmt, map_sym_tab, local_sym_tab, struc
# var = builder.alloca(ir_type, name=var_name)
# Null init
builder.store(ir.Constant(ir_type, None),
local_sym_tab[var_name])
local_sym_tab[var_name][0])
local_var_metadata[var_name] = call_type
print(f"Assigned struct {call_type} to {var_name}")
# local_sym_tab[var_name] = var
@ -139,10 +160,10 @@ def handle_assign(func, module, builder, stmt, map_sym_tab, local_sym_tab, struc
map_ptr = map_sym_tab[map_name]
if method_name in helper_func_list:
val = handle_helper_call(
rval, module, builder, func, local_sym_tab, map_sym_tab)
rval, module, builder, func, local_sym_tab, map_sym_tab, structs_sym_tab, local_var_metadata)
# var = builder.alloca(ir.IntType(64), name=var_name)
# var.align = 8
builder.store(val, local_sym_tab[var_name])
builder.store(val[0], local_sym_tab[var_name][0])
# local_sym_tab[var_name] = var
else:
print("Unsupported assignment call structure")
@ -166,7 +187,7 @@ def handle_cond(func, module, builder, cond, local_sym_tab, map_sym_tab):
return None
elif isinstance(cond, ast.Name):
if cond.id in local_sym_tab:
var = local_sym_tab[cond.id]
var = local_sym_tab[cond.id][0]
val = builder.load(var)
if val.type != ir.IntType(1):
# Convert nonzero values to true, zero to false
@ -183,12 +204,12 @@ def handle_cond(func, module, builder, cond, local_sym_tab, map_sym_tab):
return None
elif isinstance(cond, ast.Compare):
lhs = eval_expr(func, module, builder, cond.left,
local_sym_tab, map_sym_tab)
local_sym_tab, map_sym_tab)[0]
if len(cond.ops) != 1 or len(cond.comparators) != 1:
print("Unsupported complex comparison")
return None
rhs = eval_expr(func, module, builder,
cond.comparators[0], local_sym_tab, map_sym_tab)
cond.comparators[0], local_sym_tab, map_sym_tab)[0]
op = cond.ops[0]
if lhs.type != rhs.type:
@ -222,7 +243,7 @@ def handle_cond(func, module, builder, cond, local_sym_tab, map_sym_tab):
return None
def handle_if(func, module, builder, stmt, map_sym_tab, local_sym_tab):
def handle_if(func, module, builder, stmt, map_sym_tab, local_sym_tab, structs_sym_tab=None):
"""Handle if statements in the function body."""
print("Handling if statement")
start = builder.block.parent
@ -243,7 +264,7 @@ def handle_if(func, module, builder, stmt, map_sym_tab, local_sym_tab):
builder.position_at_end(then_block)
for s in stmt.body:
process_stmt(func, module, builder, s,
local_sym_tab, map_sym_tab, False)
local_sym_tab, map_sym_tab, structs_sym_tab, False)
if not builder.block.is_terminated:
builder.branch(merge_block)
@ -251,7 +272,7 @@ def handle_if(func, module, builder, stmt, map_sym_tab, local_sym_tab):
builder.position_at_end(else_block)
for s in stmt.orelse:
process_stmt(func, module, builder, s,
local_sym_tab, map_sym_tab, False)
local_sym_tab, map_sym_tab, structs_sym_tab, False)
if not builder.block.is_terminated:
builder.branch(merge_block)
@ -261,14 +282,16 @@ def handle_if(func, module, builder, stmt, map_sym_tab, local_sym_tab):
def process_stmt(func, module, builder, stmt, local_sym_tab, map_sym_tab, structs_sym_tab, did_return, ret_type=ir.IntType(64)):
print(f"Processing statement: {ast.dump(stmt)}")
if isinstance(stmt, ast.Expr):
handle_expr(func, module, builder, stmt, local_sym_tab, map_sym_tab)
handle_expr(func, module, builder, stmt, local_sym_tab,
map_sym_tab, structs_sym_tab, local_var_metadata)
elif isinstance(stmt, ast.Assign):
handle_assign(func, module, builder, stmt, map_sym_tab,
local_sym_tab, structs_sym_tab)
elif isinstance(stmt, ast.AugAssign):
raise SyntaxError("Augmented assignment not supported")
elif isinstance(stmt, ast.If):
handle_if(func, module, builder, stmt, map_sym_tab, local_sym_tab)
handle_if(func, module, builder, stmt, map_sym_tab,
local_sym_tab, structs_sym_tab)
elif isinstance(stmt, ast.Return):
if stmt.value is None:
builder.ret(ir.Constant(ir.IntType(32), 0))
@ -368,8 +391,14 @@ def allocate_mem(module, builder, body, func, ret_type, map_sym_tab, local_sym_t
var.align = ir_type.width // 8
print(
f"Pre-allocated variable {var_name} of type c_int64")
elif isinstance(rval.value, str):
ir_type = ir.PointerType(ir.IntType(8))
var = builder.alloca(ir_type, name=var_name)
var.align = 8
print(
f"Pre-allocated variable {var_name} of type string")
else:
print("Unsupported constant type")
print(f"Unsupported constant type")
continue
elif isinstance(rval, ast.BinOp):
# Assume c_int64 for now
@ -381,7 +410,7 @@ def allocate_mem(module, builder, body, func, ret_type, map_sym_tab, local_sym_t
else:
print("Unsupported assignment value type")
continue
local_sym_tab[var_name] = var
local_sym_tab[var_name] = (var, ir_type)
return local_sym_tab
@ -441,7 +470,6 @@ def process_bpf_chunk(func_node, module, return_type, map_sym_tab, structs_sym_t
process_func_body(module, builder, func_node, func,
ret_type, map_sym_tab, structs_sym_tab)
return func
@ -517,3 +545,46 @@ def infer_return_type(func_node: ast.FunctionDef):
raise ValueError("Conflicting return types:"
f"{found_type} vs {t}")
return found_type or "None"
# For string assignment to fixed-size arrays
def assign_string_to_array(builder, target_array_ptr, source_string_ptr, array_length):
"""
Copy a string (i8*) to a fixed-size array ([N x i8]*)
"""
# Create a loop to copy characters one by one
entry_block = builder.block
copy_block = builder.append_basic_block("copy_char")
end_block = builder.append_basic_block("copy_end")
# Create loop counter
i = builder.alloca(ir.IntType(32))
builder.store(ir.Constant(ir.IntType(32), 0), i)
# Start the loop
builder.branch(copy_block)
# Copy loop
builder.position_at_end(copy_block)
idx = builder.load(i)
in_bounds = builder.icmp_unsigned('<', idx, ir.Constant(ir.IntType(32), array_length))
builder.cbranch(in_bounds, copy_block, end_block)
with builder.if_then(in_bounds):
# Load character from source
src_ptr = builder.gep(source_string_ptr, [idx])
char = builder.load(src_ptr)
# Store character in target
dst_ptr = builder.gep(target_array_ptr, [ir.Constant(ir.IntType(32), 0), idx])
builder.store(char, dst_ptr)
# Increment counter
next_idx = builder.add(idx, ir.Constant(ir.IntType(32), 1))
builder.store(next_idx, i)
builder.position_at_end(end_block)
# Ensure null termination
last_idx = ir.Constant(ir.IntType(32), array_length - 1)
null_ptr = builder.gep(target_array_ptr, [ir.Constant(ir.IntType(32), 0), last_idx])
builder.store(ir.Constant(ir.IntType(8), 0), null_ptr)

View File

@ -30,3 +30,6 @@ class PerfEventArray:
self.key_type = key_size
self.value_type = value_size
self.entries = {}
def output(self, data):
pass # Placeholder for output method

View File

@ -28,12 +28,42 @@ def process_bpf_struct(cls_node, module):
for item in cls_node.body:
if isinstance(item, ast.AnnAssign) and isinstance(item.target, ast.Name):
print(f"Field: {item.target.id}, Type: "
f"{ast.dump(item.annotation)}")
field_names.append(item.target.id)
field_types.append(ctypes_to_ir(item.annotation.id))
if isinstance(item.annotation, ast.Call) and isinstance(item.annotation.func, ast.Name) and item.annotation.func.id == "str":
# This is a char array with fixed length
# TODO: For now assuming str is always called with constant
field_types.append(ir.ArrayType(
ir.IntType(8), item.annotation.args[0].value))
else:
field_types.append(ctypes_to_ir(item.annotation.id))
curr_offset = 0
for ftype in field_types:
if isinstance(ftype, ir.IntType):
fsize = ftype.width // 8
alignment = fsize
elif isinstance(ftype, ir.ArrayType):
fsize = ftype.count * (ftype.element.width // 8)
alignment = ftype.element.width // 8
elif isinstance(ftype, ir.PointerType):
fsize = 8
alignment = 8
else:
print(f"Unsupported field type in struct {struct_name}")
return
padding = (alignment - (curr_offset % alignment)) % alignment
curr_offset += padding
curr_offset += fsize
final_padding = (8 - (curr_offset % 8)) % 8
total_size = curr_offset + final_padding
struct_type = ir.LiteralStructType(field_types)
structs_sym_tab[struct_name] = {
"type": struct_type,
"fields": {name: idx for idx, name in enumerate(field_names)}
"fields": {name: idx for idx, name in enumerate(field_names)},
"size": total_size,
"field_types": field_types,
}
print(f"Created struct {struct_name} with fields {field_names}")