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WIP: allow pointer assignments to var

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This commit is contained in:
Pragyansh Chaturvedi
2025-10-10 13:48:40 +05:30
parent 1d517d4e09
commit 99aacca94b
4 changed files with 26 additions and 9 deletions
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19
pythonbpf/assign_pass.py
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@ -1,7 +1,7 @@
import ast
import logging
from llvmlite import ir
from pythonbpf.expr import eval_expr
from pythonbpf.expr import eval_expr, get_base_type_and_depth
logger = logging.getLogger(__name__)
@ -38,6 +38,9 @@ def handle_variable_assignment(
val, val_type = val_result
if val_type != var_type:
logger.info(f"val = {val}")
logger.info(f"var = {var_ptr}")
logger.info(f"truthy {var_type}")
if isinstance(val_type, ir.IntType) and isinstance(var_type, ir.IntType):
# Allow implicit int widening
if val_type.width < var_type.width:
@ -46,10 +49,24 @@ def handle_variable_assignment(
elif val_type.width > var_type.width:
val = builder.trunc(val, var_type)
logger.info(f"Implicitly truncated int for variable {var_name}")
elif isinstance(val_type, ir.IntType) and isinstance(var_type, ir.PointerType):
ptr_target, ptr_depth = get_base_type_and_depth(var_type)
if ptr_target.width > val_type.width:
val = builder.sext(val, ptr_target)
elif ptr_target.width < val_type.width:
val = builder.trunc(val, ptr_target)
if ptr_depth > 1:
# NOTE: This is assignment to a PTR_TO_MAP_VALUE_OR_NULL
var_ptr_tmp = local_sym_tab[f"{var_name}_tmp"].var
builder.store(val, var_ptr_tmp)
val = var_ptr_tmp
else:
logger.error(
f"Type mismatch for variable {var_name}: {val_type} vs {var_type}"
)
logger.error(f"var_type: {isinstance(var_type, ir.PointerType)}")
logger.error(f"val_type: {isinstance(val_type, ir.IntType)}")
return False
builder.store(val, var_ptr)

4
pythonbpf/expr/__init__.py
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@ -1,4 +1,4 @@
from .expr_pass import eval_expr, handle_expr
from .type_normalization import convert_to_bool
from .type_normalization import convert_to_bool, get_base_type_and_depth
__all__ = ["eval_expr", "handle_expr", "convert_to_bool"]
__all__ = ["eval_expr", "handle_expr", "convert_to_bool", "get_base_type_and_depth"]

6
pythonbpf/expr/type_normalization.py
View File

@ -16,7 +16,7 @@ COMPARISON_OPS = {
}
def _get_base_type_and_depth(ir_type):
def get_base_type_and_depth(ir_type):
"""Get the base type for pointer types."""
cur_type = ir_type
depth = 0
@ -88,8 +88,8 @@ def _normalize_types(func, builder, lhs, rhs):
logger.error(f"Type mismatch: {lhs.type} vs {rhs.type}")
return None, None
else:
lhs_base, lhs_depth = _get_base_type_and_depth(lhs.type)
rhs_base, rhs_depth = _get_base_type_and_depth(rhs.type)
lhs_base, lhs_depth = get_base_type_and_depth(lhs.type)
rhs_base, rhs_depth = get_base_type_and_depth(rhs.type)
if lhs_base == rhs_base:
if lhs_depth < rhs_depth:
rhs = _deref_to_depth(func, builder, rhs, rhs_depth - lhs_depth)

6
pythonbpf/functions/functions_pass.py
View File

@ -461,8 +461,8 @@ def allocate_mem(
var = builder.alloca(ir_type, name=var_name)
# declare an intermediate ptr type for map lookup
ir_type = ir.IntType(64)
var_tmp = builder.alloca(ir_type, name=f"{var_name}_tmp")
tmp_ir_type = ir.IntType(64)
var_tmp = builder.alloca(tmp_ir_type, name=f"{var_name}_tmp")
double_alloc = True
# var.align = ir_type.width // 8
logger.info(
@ -507,7 +507,7 @@ def allocate_mem(
local_sym_tab[var_name] = LocalSymbol(var, ir_type)
if double_alloc:
local_sym_tab[f"{var_name}_tmp"] = LocalSymbol(var_tmp, ir_type)
local_sym_tab[f"{var_name}_tmp"] = LocalSymbol(var_tmp, tmp_ir_type)
return local_sym_tab