Associate types with program

I originally envisioned types as dumb descriptors. This mostly works for
C because in C, types are fairly simple. However, even then the
drgn_program_member_info() API is awkward. You should be able to look up
a member directly from a type, but we need the program for caching
purposes. This has also held me back from adding offsetof() or
has_member() APIs.

Things get even messier with C++. C++ template parameters can be objects
(e.g., template <int N>). Such parameters would best be represented by a
drgn object, which we need a drgn program for. Static members are a
similar case.

So, let's reimagine types as being owned by a program. This has a few
parts:

1. In libdrgn, simple types are now created by factory functions,
   drgn_foo_type_create().
2. To handle their variable length fields, compound types, enum types,
   and function types are constructed with a "builder" API.
3. Simple types are deduplicated.
4. The Python type factory functions are replaced by methods of the
   Program class.
5. While we're changing the API, the parameters to pointer_type() and
   array_type() are reordered to be more logical (and to allow
   pointer_type() to take a default size of None for the program's
   default pointer size).
6. Likewise, the type factory methods take qualifiers as a keyword
   argument only.

A big part of this change is updating the tests and splitting up large
test cases into smaller ones in a few places.

Signed-off-by: Omar Sandoval <[email protected]>

Author: osandov

_drgn.pyi

@@ -7,6 +7,7 @@ Programs
 --------
 
 .. drgndoc:: Program
+    :exclude: (void|int|bool|float|complex|struct|union|class|enum|typedef|pointer|array|function)_type
 .. drgndoc:: ProgramFlags
 .. drgndoc:: FindObjectFlags
 
@@ -95,19 +96,19 @@ Type Constructors
 Custom drgn types can be created with the following factory functions. These
 can be used just like types obtained from :meth:`Program.type()`.
 
-.. drgndoc:: void_type
-.. drgndoc:: int_type
-.. drgndoc:: bool_type
-.. drgndoc:: float_type
-.. drgndoc:: complex_type
-.. drgndoc:: struct_type
-.. drgndoc:: union_type
-.. drgndoc:: class_type
-.. drgndoc:: enum_type
-.. drgndoc:: typedef_type
-.. drgndoc:: pointer_type
-.. drgndoc:: array_type
-.. drgndoc:: function_type
+.. drgndoc:: Program.void_type
+.. drgndoc:: Program.int_type
+.. drgndoc:: Program.bool_type
+.. drgndoc:: Program.float_type
+.. drgndoc:: Program.complex_type
+.. drgndoc:: Program.struct_type
+.. drgndoc:: Program.union_type
+.. drgndoc:: Program.class_type
+.. drgndoc:: Program.enum_type
+.. drgndoc:: Program.typedef_type
+.. drgndoc:: Program.pointer_type
+.. drgndoc:: Program.array_type
+.. drgndoc:: Program.function_type
 
 Miscellaneous
 -------------

docs/api_reference.rst

@@ -72,28 +72,15 @@
     TypeMember,
     TypeParameter,
     _with_libkdumpfile as _with_libkdumpfile,
-    array_type,
-    bool_type,
     cast,
-    class_type,
-    complex_type,
     container_of,
-    enum_type,
     filename_matches,
-    float_type,
-    function_type,
     host_platform,
-    int_type,
-    pointer_type,
     program_from_core_dump,
     program_from_kernel,
     program_from_pid,
     reinterpret,
     sizeof,
-    struct_type,
-    typedef_type,
-    union_type,
-    void_type,
 )
 
 __all__ = (
@@ -122,29 +109,16 @@
     "TypeKind",
     "TypeMember",
     "TypeParameter",
-    "array_type",
-    "bool_type",
     "cast",
-    "class_type",
-    "complex_type",
     "container_of",
-    "enum_type",
     "execscript",
     "filename_matches",
-    "float_type",
-    "function_type",
     "host_platform",
-    "int_type",
-    "pointer_type",
     "program_from_core_dump",
     "program_from_kernel",
     "program_from_pid",
     "reinterpret",
     "sizeof",
-    "struct_type",
-    "typedef_type",
-    "union_type",
-    "void_type",
 )
 
 

drgn/__init__.py

@@ -85,6 +85,8 @@ def list_first_entry_or_null(
     head = head.read_()
     pos = head.next.read_()
     if pos == head:
+        if isinstance(type, str):
+            type = head.prog_.type(type)
         return NULL(head.prog_, head.prog_.pointer_type(type))
     else:
         return container_of(pos, type, member)

drgn/helpers/linux/list.py

@@ -425,6 +425,7 @@ struct drgn_type {
 		enum drgn_primitive_type primitive;
 		/* These are the qualifiers for the wrapped type, not this type. */
 		enum drgn_qualifiers qualifiers;
+		struct drgn_program *program;
 		const struct drgn_language *language;
 		/*
 		 * This mess of unions is used to make this as compact as possible. Use
@@ -493,6 +494,12 @@ static inline bool drgn_type_is_complete(struct drgn_type *type)
 	return type->_private.is_complete;
 }
 
+static inline struct drgn_program *
+drgn_type_program(struct drgn_type *type)
+{
+	return type->_private.program;
+}
+
 /** Get the language of a type. */
 static inline const struct drgn_language *
 drgn_type_language(struct drgn_type *type)