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1=====================================2CodeView Type Records3=====================================4 5 6.. contents::7 :local:8 9.. _types_intro:10 11Introduction12============13 14This document describes the usage and serialization format of the various15CodeView type records that LLVM understands. This document does not describe16every single CodeView type record that is defined. In some cases, this is17because the records are clearly deprecated and can only appear in very old18software (e.g. the 16-bit types). On other cases, it is because the records19have never been observed in practice. This could be because they are only20generated for non-C++ code (e.g. Visual Basic, C#), or because they have been21made obsolete by newer records, or any number of other reasons. However, the22records we describe here should cover 99% of type records that one can expect23to encounter when dealing with modern C++ toolchains.24 25Record Categories26=================27 28We can think of a sequence of CodeView type records as an array of variable length29`leaf records`. Each such record describes its own length as part of a fixed-size30header, as well as the kind of record it is. Leaf records are either padded to 431bytes (if this type stream appears in a TPI/IPI stream of a PDB) or not padded at32all (if this type stream appears in the ``.debug$T`` section of an object file).33Padding is implemented by inserting a decreasing sequence of `<_padding_records>`34that terminates with ``LF_PAD0``.35 36The final category of record is a ``member record``. One particular leaf type --37``LF_FIELDLIST`` -- contains a series of embedded records. While the outer38``LF_FIELDLIST`` describes its length (like any other leaf record), the embedded39records -- called ``member records`` do not.40 41.. _leaf_types:42 43Leaf Records44------------45 46All leaf records begin with the following 4-byte prefix:47 48.. code-block:: c++49 50 struct RecordHeader {51 uint16_t RecordLen; // Record length, not including this 2-byte field.52 uint16_t RecordKind; // Record kind enum.53 };54 55LF_POINTER (0x1002)56^^^^^^^^^^^^^^^^^^^57 58**Usage:** Describes a pointer to another type.59 60**Layout:**61 62.. code-block:: none63 64 .--------------------.-- +065 | Referent Type |66 .--------------------.-- +467 | Attributes |68 .--------------------.-- +869 | Member Ptr Info | Only present if |Attributes| indicates this is a member pointer.70 .--------------------.-- +E71 72Attributes is a bitfield with the following layout:73 74.. code-block:: none75 76 .-----------------------------------------------------------------------------------------------------.77 | Unused | Flags | Size | Modifiers | Mode | Kind |78 .-----------------------------------------------------------------------------------------------------.79 | | | | | | |80 0x100 +0x16 +0x13 +0xD +0x8 +0x5 +0x081 82where the various fields are defined by the following enums:83 84.. code-block:: c++85 86 enum class PointerKind : uint8_t {87 Near16 = 0x00, // 16 bit pointer88 Far16 = 0x01, // 16:16 far pointer89 Huge16 = 0x02, // 16:16 huge pointer90 BasedOnSegment = 0x03, // based on segment91 BasedOnValue = 0x04, // based on value of base92 BasedOnSegmentValue = 0x05, // based on segment value of base93 BasedOnAddress = 0x06, // based on address of base94 BasedOnSegmentAddress = 0x07, // based on segment address of base95 BasedOnType = 0x08, // based on type96 BasedOnSelf = 0x09, // based on self97 Near32 = 0x0a, // 32 bit pointer98 Far32 = 0x0b, // 16:32 pointer99 Near64 = 0x0c // 64 bit pointer100 };101 enum class PointerMode : uint8_t {102 Pointer = 0x00, // "normal" pointer103 LValueReference = 0x01, // "old" reference104 PointerToDataMember = 0x02, // pointer to data member105 PointerToMemberFunction = 0x03, // pointer to member function106 RValueReference = 0x04 // r-value reference107 };108 enum class PointerModifiers : uint8_t {109 None = 0x00, // "normal" pointer110 Flat32 = 0x01, // "flat" pointer111 Volatile = 0x02, // pointer is marked volatile112 Const = 0x04, // pointer is marked const113 Unaligned = 0x08, // pointer is marked unaligned114 Restrict = 0x10, // pointer is marked restrict115 };116 enum class PointerFlags : uint8_t {117 WinRTSmartPointer = 0x01, // pointer is a WinRT smart pointer118 LValueRefThisPointer = 0x02, // pointer is a 'this' pointer of a member function with ref qualifier (e.g. void X::foo() &)119 RValueRefThisPointer = 0x04 // pointer is a 'this' pointer of a member function with ref qualifier (e.g. void X::foo() &&)120 };121 122The ``Size`` field of the Attributes bitmask is a 1-byte value indicating the123pointer size. For example, a `void*` would have a size of either 4 or 8 depending124on the target architecture. On the other hand, if ``Mode`` indicates that this is125a pointer to member function or pointer to data member, then the size can be any126implementation-defined number.127 128The ``Member Ptr Info`` field of the ``LF_POINTER`` record is only present if the129attributes indicate that this is a pointer to member.130 131Note that "plain" pointers to primitive types are not represented by ``LF_POINTER``132records, they are indicated by special reserved :ref:`TypeIndex values <type_indices>`.133 134 135 136LF_MODIFIER (0x1001)137^^^^^^^^^^^^^^^^^^^^138 139LF_PROCEDURE (0x1008)140^^^^^^^^^^^^^^^^^^^^^141 142LF_MFUNCTION (0x1009)143^^^^^^^^^^^^^^^^^^^^^144 145LF_LABEL (0x000e)146^^^^^^^^^^^^^^^^^147 148LF_ARGLIST (0x1201)149^^^^^^^^^^^^^^^^^^^150 151LF_FIELDLIST (0x1203)152^^^^^^^^^^^^^^^^^^^^^153 154LF_ARRAY (0x1503)155^^^^^^^^^^^^^^^^^156 157LF_CLASS (0x1504)158^^^^^^^^^^^^^^^^^159 160LF_STRUCTURE (0x1505)161^^^^^^^^^^^^^^^^^^^^^162 163LF_INTERFACE (0x1519)164^^^^^^^^^^^^^^^^^^^^^165 166LF_UNION (0x1506)167^^^^^^^^^^^^^^^^^168 169LF_ENUM (0x1507)170^^^^^^^^^^^^^^^^171 172LF_TYPESERVER2 (0x1515)173^^^^^^^^^^^^^^^^^^^^^^^174 175LF_VFTABLE (0x151d)176^^^^^^^^^^^^^^^^^^^177 178LF_VTSHAPE (0x000a)179^^^^^^^^^^^^^^^^^^^180 181LF_BITFIELD (0x1205)182^^^^^^^^^^^^^^^^^^^^183 184LF_FUNC_ID (0x1601)185^^^^^^^^^^^^^^^^^^^186 187LF_MFUNC_ID (0x1602)188^^^^^^^^^^^^^^^^^^^^189 190LF_BUILDINFO (0x1603)191^^^^^^^^^^^^^^^^^^^^^192 193LF_SUBSTR_LIST (0x1604)194^^^^^^^^^^^^^^^^^^^^^^^195 196LF_STRING_ID (0x1605)197^^^^^^^^^^^^^^^^^^^^^198 199LF_UDT_SRC_LINE (0x1606)200^^^^^^^^^^^^^^^^^^^^^^^^201 202LF_UDT_MOD_SRC_LINE (0x1607)203^^^^^^^^^^^^^^^^^^^^^^^^^^^^204 205LF_METHODLIST (0x1206)206^^^^^^^^^^^^^^^^^^^^^^207 208LF_PRECOMP (0x1509)209^^^^^^^^^^^^^^^^^^^210 211LF_ENDPRECOMP (0x0014)212^^^^^^^^^^^^^^^^^^^^^^213 214.. _member_types:215 216Member Records217--------------218 219LF_BCLASS (0x1400)220^^^^^^^^^^^^^^^^^^221 222LF_BINTERFACE (0x151a)223^^^^^^^^^^^^^^^^^^^^^^224 225LF_VBCLASS (0x1401)226^^^^^^^^^^^^^^^^^^^227 228LF_IVBCLASS (0x1402)229^^^^^^^^^^^^^^^^^^^^230 231LF_VFUNCTAB (0x1409)232^^^^^^^^^^^^^^^^^^^^233 234LF_STMEMBER (0x150e)235^^^^^^^^^^^^^^^^^^^^236 237LF_METHOD (0x150f)238^^^^^^^^^^^^^^^^^^239 240LF_MEMBER (0x150d)241^^^^^^^^^^^^^^^^^^242 243LF_NESTTYPE (0x1510)244^^^^^^^^^^^^^^^^^^^^245 246LF_ONEMETHOD (0x1511)247^^^^^^^^^^^^^^^^^^^^^248 249LF_ENUMERATE (0x1502)250^^^^^^^^^^^^^^^^^^^^^251 252LF_INDEX (0x1404)253^^^^^^^^^^^^^^^^^254 255.. _padding_records:256 257Padding Records258---------------259 260LF_PADn (0xf0 + n)261^^^^^^^^^^^^^^^^^^262