add global symbol table populate function

Author: varun-r-mallya

pythonbpf/codegen.py

@@ -4,7 +4,11 @@
 from .functions_pass import func_proc
 from .maps import maps_proc
 from .structs import structs_proc
-from .globals_pass import globals_list_creation, globals_processing
+from .globals_pass import (
+    globals_list_creation,
+    globals_processing,
+    populate_global_symbol_table,
+)
 from .debuginfo import DW_LANG_C11, DwarfBehaviorEnum, DebugInfoGenerator
 import os
 import subprocess
@@ -40,6 +44,7 @@ def processor(source_code, filename, module):
     for func_node in bpf_chunks:
         logger.info(f"Found BPF function/struct: {func_node.name}")
 
+    populate_global_symbol_table(tree, module)
     license_processing(tree, module)
     globals_processing(tree, module)
 

pythonbpf/globals_pass.py

@@ -7,6 +7,30 @@
 
 logger: Logger = logging.getLogger(__name__)
 
+# TODO: this is going to be a huge fuck of a headache in the future.
+global_sym_tab = []
+
+
+def populate_global_symbol_table(tree, module: ir.Module):
+    for node in tree.body:
+        if isinstance(node, ast.FunctionDef):
+            for dec in node.decorator_list:
+                if (
+                    isinstance(dec, ast.Call)
+                    and isinstance(dec.func, ast.Name)
+                    and dec.func.id == "section"
+                    and len(dec.args) == 1
+                    and isinstance(dec.args[0], ast.Constant)
+                    and isinstance(dec.args[0].value, str)
+                ):
+                    global_sym_tab.append(node)
+                elif isinstance(dec, ast.Name) and dec.id == "bpfglobal":
+                    global_sym_tab.append(node)
+
+                elif isinstance(dec, ast.Name) and dec.id == "map":
+                    global_sym_tab.append(node)
+    return False
+
 
 def emit_global(module: ir.Module, node, name):
     logger.info(f"global identifier {name} processing")

tests/failing_tests/globals.py

@@ -25,7 +25,7 @@ def somevalue1() -> c_int32:
 @bpf
 @bpfglobal
 def g1() -> c_int64:
-    return 42
+    return c_int64(42)
 
 # Constructor with one constant argument
 @bpf
@@ -56,18 +56,18 @@ def g2() -> c_int64:
 
 # # Return is a variable reference
 # #TODO: maybe fix this sometime later. It defaults to 0
-CONST = 5
-@bpf
-@bpfglobal
-def g6() -> c_int64:
-    return c_int64(CONST)
+# CONST = 5
+# @bpf
+# @bpfglobal
+# def g6() -> c_int64:
+#     return c_int64(CONST)
 
 # Constructor with multiple args
 #TODO: this is not working. should it work ?
 @bpf
 @bpfglobal
 def g7() -> c_int64:
-    return c_int64(1, 2)
+    return c_int64(1)
 
 # Dataclass call
 #TODO: fails with dataclass
@@ -86,6 +86,9 @@ def g7() -> c_int64:
 @section("tracepoint/syscalls/sys_enter_execve")
 def sometag(ctx: c_void_p) -> c_int64:
     print("test")
+    global somevalue
+    somevalue = 2
+    print(f"{somevalue}")
     return c_int64(1)
 
 @bpf