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Allow access from struct fields

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This commit is contained in:
Pragyansh Chaturvedi
2025-09-26 23:01:14 +05:30
parent 8c2196c05c
commit de5cc438ab
4 changed files with 65 additions and 9 deletions
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46
pythonbpf/bpf_helper_handler.py
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@ -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, local_var_metadata=None):
def bpf_ktime_get_ns_emitter(call, map_ptr, module, builder, func, local_sym_tab=None, struct_sym_tab=None, local_var_metadata=None):
"""
Emit LLVM IR for bpf_ktime_get_ns helper function call.
"""
@ -63,7 +63,7 @@ def bpf_map_lookup_elem_emitter(call, map_ptr, module, builder, func, local_sym_
return result, ir.PointerType()
def bpf_printk_emitter(call, map_ptr, module, builder, func, local_sym_tab=None, local_var_metadata=None):
def bpf_printk_emitter(call, map_ptr, module, builder, func, local_sym_tab=None, struct_sym_tab=None, local_var_metadata=None):
if not hasattr(func, "_fmt_counter"):
func._fmt_counter = 0
@ -101,10 +101,42 @@ def bpf_printk_emitter(call, map_ptr, module, builder, func, local_sym_tab=None,
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.")
elif isinstance(value.value, ast.Attribute):
# object field access from struct
if isinstance(value.value.value, ast.Name) and local_sym_tab and value.value.value.id in local_sym_tab:
var_name = value.value.value.id
field_name = value.value.attr
if local_var_metadata and var_name in local_var_metadata:
var_type = local_var_metadata[var_name]
if var_type in struct_sym_tab:
struct_info = struct_sym_tab[var_type]
if field_name in struct_info["fields"]:
field_index = struct_info["fields"][field_name]
field_type = struct_info["field_types"][field_index]
if isinstance(field_type, ir.IntType):
fmt_parts.append("%lld")
exprs.append(value.value)
elif field_type == ir.PointerType(ir.IntType(8)):
fmt_parts.append("%s")
exprs.append(value.value)
else:
raise NotImplementedError(
"Only integer and pointer types are supported in formatted values.")
else:
raise ValueError(
f"Field {field_name} not found in struct {var_type}.")
else:
raise ValueError(
f"Struct type {var_type} for variable {var_name} not found in struct symbol table.")
else:
raise ValueError(
f"Metadata for variable {var_name} not found in local variable metadata.")
else:
raise ValueError(
f"Variable {value.value.value.id} not found in local symbol table.")
else:
raise NotImplementedError(
"Only simple variable names are supported in formatted values.")
@ -136,8 +168,9 @@ 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]:
print(f"{ast.dump(expr)}")
val, _ = eval_expr(func, module, builder,
expr, local_sym_tab, None)
expr, local_sym_tab, None, struct_sym_tab, local_var_metadata)
if val:
if isinstance(val.type, ir.PointerType):
val = builder.ptrtoint(val, ir.IntType(64))
@ -339,7 +372,7 @@ def bpf_map_delete_elem_emitter(call, map_ptr, module, builder, func, local_sym_
return result, None
def bpf_get_current_pid_tgid_emitter(call, map_ptr, module, builder, func, local_sym_tab=None, local_var_metadata=None):
def bpf_get_current_pid_tgid_emitter(call, map_ptr, module, builder, func, local_sym_tab=None, struct_sym_tab=None, local_var_metadata=None):
"""
Emit LLVM IR for bpf_get_current_pid_tgid helper function call.
"""
@ -420,11 +453,12 @@ helper_func_list = {
def handle_helper_call(call, module, builder, func, local_sym_tab=None, map_sym_tab=None, struct_sym_tab=None, local_var_metadata=None):
print(local_var_metadata)
if isinstance(call.func, ast.Name):
func_name = call.func.id
if func_name in helper_func_list:
# it is not a map method call
return helper_func_list[func_name](call, None, module, builder, func, local_sym_tab)
return helper_func_list[func_name](call, None, module, builder, func, local_sym_tab, struct_sym_tab, local_var_metadata)
else:
raise NotImplementedError(
f"Function {func_name} is not implemented as a helper function.")