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Add deref(), add delete helper, refactor pre-alloc

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Pragyansh Chaturvedi
2025-09-12 04:24:40 +05:30
parent 0950d0550c
commit a09e4e1bb6
5 changed files with 156 additions and 25 deletions
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51
pythonbpf/functions_pass.py
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@ -79,6 +79,17 @@ def handle_assign(func, module, builder, stmt, map_sym_tab, local_sym_tab):
builder.store(val, local_sym_tab[var_name])
# 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)
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])
# local_sym_tab[var_name] = var
print(f"Dereferenced and assigned to {var_name}")
else:
print(f"Unsupported assignment call type: {call_type}")
elif isinstance(rval.func, ast.Attribute):
@ -227,16 +238,16 @@ def process_stmt(func, module, builder, stmt, local_sym_tab, map_sym_tab, did_re
return did_return
def process_func_body(module, builder, func_node, func, ret_type, map_sym_tab):
"""Process the body of a bpf function"""
# TODO: A lot. We just have print -> bpf_trace_printk for now
did_return = False
local_sym_tab = {}
# pre-allocate dynamic variables
for stmt in func_node.body:
if isinstance(stmt, ast.Assign):
def allocate_mem(module, builder, body, func, ret_type, map_sym_tab, local_sym_tab):
for stmt in body:
if isinstance(stmt, ast.If):
if stmt.body:
local_sym_tab = allocate_mem(
module, builder, stmt.body, func, ret_type, map_sym_tab, local_sym_tab)
if stmt.orelse:
local_sym_tab = allocate_mem(
module, builder, stmt.orelse, func, ret_type, map_sym_tab, local_sym_tab)
elif isinstance(stmt, ast.Assign):
if len(stmt.targets) != 1:
print("Unsupported multiassignment")
continue
@ -262,6 +273,13 @@ def process_func_body(module, builder, func_node, func, ret_type, map_sym_tab):
var.align = ir_type.width // 8
print(
f"Pre-allocated variable {var_name} for helper")
elif call_type == "deref" and len(rval.args) == 1:
# Assume return type is int64 for now
ir_type = ir.IntType(64)
var = builder.alloca(ir_type, name=var_name)
var.align = ir_type.width // 8
print(
f"Pre-allocated variable {var_name} for deref")
elif isinstance(rval.func, ast.Attribute):
ir_type = ir.PointerType(ir.IntType(64))
var = builder.alloca(ir_type, name=var_name)
@ -292,6 +310,19 @@ def process_func_body(module, builder, func_node, func, ret_type, map_sym_tab):
print("Unsupported assignment value type")
continue
local_sym_tab[var_name] = var
return local_sym_tab
def process_func_body(module, builder, func_node, func, ret_type, map_sym_tab):
"""Process the body of a bpf function"""
# TODO: A lot. We just have print -> bpf_trace_printk for now
did_return = False
local_sym_tab = {}
# pre-allocate dynamic variables
local_sym_tab = allocate_mem(
module, builder, func_node.body, func, ret_type, map_sym_tab, local_sym_tab)
print(f"Local symbol table: {local_sym_tab.keys()}")