170 lines
8.8 KiB
ReStructuredText
170 lines
8.8 KiB
ReStructuredText
|
=====================================
|
||
|
|
The PDB File Format
|
||
|
|
=====================================
|
||
|
|
|
||
|
|
.. contents::
|
||
|
|
:local:
|
||
|
|
|
||
|
|
.. _pdb_intro:
|
||
|
|
|
||
|
|
Introduction
|
||
|
|
============
|
||
|
|
|
||
|
|
PDB (Program Database) is a file format invented by Microsoft and which contains
|
||
|
|
debug information that can be consumed by debuggers and other tools. Since
|
||
|
|
officially supported APIs exist on Windows for querying debug information from
|
||
|
|
PDBs even without the user understanding the internals of the file format, a
|
||
|
|
large ecosystem of tools has been built for Windows to consume this format. In
|
||
|
|
order for Clang to be able to generate programs that can interoperate with these
|
||
|
|
tools, it is necessary for us to generate PDB files ourselves.
|
||
|
|
|
||
|
|
At the same time, LLVM has a long history of being able to cross-compile from
|
||
|
|
any platform to any platform, and we wish for the same to be true here. So it
|
||
|
|
is necessary for us to understand the PDB file format at the byte-level so that
|
||
|
|
we can generate PDB files entirely on our own.
|
||
|
|
|
||
|
|
This manual describes what we know about the PDB file format today. The layout
|
||
|
|
of the file, the various streams contained within, the format of individual
|
||
|
|
records within, and more.
|
||
|
|
|
||
|
|
We would like to extend our heartfelt gratitude to Microsoft, without whom we
|
||
|
|
would not be where we are today. Much of the knowledge contained within this
|
||
|
|
manual was learned through reading code published by Microsoft on their `GitHub
|
||
|
|
repo <https://github.com/Microsoft/microsoft-pdb>`__.
|
||
|
|
|
||
|
|
.. _pdb_layout:
|
||
|
|
|
||
|
|
File Layout
|
||
|
|
===========
|
||
|
|
|
||
|
|
.. important::
|
||
|
|
Unless otherwise specified, all numeric values are encoded in little endian.
|
||
|
|
If you see a type such as ``uint16_t`` or ``uint64_t`` going forward, always
|
||
|
|
assume it is little endian!
|
||
|
|
|
||
|
|
.. toctree::
|
||
|
|
:hidden:
|
||
|
|
|
||
|
|
MsfFile
|
||
|
|
PdbStream
|
||
|
|
TpiStream
|
||
|
|
DbiStream
|
||
|
|
ModiStream
|
||
|
|
PublicStream
|
||
|
|
GlobalStream
|
||
|
|
HashTable
|
||
|
|
CodeViewSymbols
|
||
|
|
CodeViewTypes
|
||
|
|
|
||
|
|
.. _msf:
|
||
|
|
|
||
|
|
The MSF Container
|
||
|
|
-----------------
|
||
|
|
A PDB file is an MSF (Multi-Stream Format) file. An MSF file is a "file system
|
||
|
|
within a file". It contains multiple streams (aka files) which can represent
|
||
|
|
arbitrary data, and these streams are divided into blocks which may not
|
||
|
|
necessarily be contiguously laid out within the MSF container file.
|
||
|
|
Additionally, the MSF contains a stream directory (aka MFT) which describes how
|
||
|
|
the streams (files) are laid out within the MSF.
|
||
|
|
|
||
|
|
For more information about the MSF container format, stream directory, and
|
||
|
|
block layout, see :doc:`MsfFile`.
|
||
|
|
|
||
|
|
.. _streams:
|
||
|
|
|
||
|
|
Streams
|
||
|
|
-------
|
||
|
|
The PDB format contains a number of streams which describe various information
|
||
|
|
such as the types, symbols, source files, and compilands (e.g. object files)
|
||
|
|
of a program, as well as some additional streams containing hash tables that are
|
||
|
|
used by debuggers and other tools to provide fast lookup of records and types
|
||
|
|
by name, and various other information about how the program was compiled such
|
||
|
|
as the specific toolchain used, and more. A summary of streams contained in a
|
||
|
|
PDB file is as follows:
|
||
|
|
|
||
|
|
+--------------------+------------------------------+-------------------------------------------+
|
||
|
|
| Name | Stream Index | Contents |
|
||
|
|
+====================+==============================+===========================================+
|
||
|
|
| Old Directory | - Fixed Stream Index 0 | - Previous MSF Stream Directory |
|
||
|
|
+--------------------+------------------------------+-------------------------------------------+
|
||
|
|
| PDB Stream | - Fixed Stream Index 1 | - Basic File Information |
|
||
|
|
| | | - Fields to match EXE to this PDB |
|
||
|
|
| | | - Map of named streams to stream indices |
|
||
|
|
+--------------------+------------------------------+-------------------------------------------+
|
||
|
|
| TPI Stream | - Fixed Stream Index 2 | - CodeView Type Records |
|
||
|
|
| | | - Index of TPI Hash Stream |
|
||
|
|
+--------------------+------------------------------+-------------------------------------------+
|
||
|
|
| DBI Stream | - Fixed Stream Index 3 | - Module/Compiland Information |
|
||
|
|
| | | - Indices of individual module streams |
|
||
|
|
| | | - Indices of public / global streams |
|
||
|
|
| | | - Section Contribution Information |
|
||
|
|
| | | - Source File Information |
|
||
|
|
| | | - References to streams containing |
|
||
|
|
| | | FPO / PGO Data |
|
||
|
|
+--------------------+------------------------------+-------------------------------------------+
|
||
|
|
| IPI Stream | - Fixed Stream Index 4 | - CodeView Type Records |
|
||
|
|
| | | - Index of IPI Hash Stream |
|
||
|
|
+--------------------+------------------------------+-------------------------------------------+
|
||
|
|
| /LinkInfo | - Contained in PDB Stream | - Unknown |
|
||
|
|
| | Named Stream map | |
|
||
|
|
+--------------------+------------------------------+-------------------------------------------+
|
||
|
|
| /src/headerblock | - Contained in PDB Stream | - Summary of embedded source file content |
|
||
|
|
| | Named Stream map | (e.g. natvis files) |
|
||
|
|
+--------------------+------------------------------+-------------------------------------------+
|
||
|
|
| /names | - Contained in PDB Stream | - PDB-wide global string table used for |
|
||
|
|
| | Named Stream map | string de-duplication |
|
||
|
|
+--------------------+------------------------------+-------------------------------------------+
|
||
|
|
| Module Info Stream | - Contained in DBI Stream | - CodeView Symbol Records for this module |
|
||
|
|
| | - One for each compiland | - Line Number Information |
|
||
|
|
+--------------------+------------------------------+-------------------------------------------+
|
||
|
|
| Public Stream | - Contained in DBI Stream | - Public (Exported) Symbol Records |
|
||
|
|
| | | - Index of Public Hash Stream |
|
||
|
|
+--------------------+------------------------------+-------------------------------------------+
|
||
|
|
| Global Stream | - Contained in DBI Stream | - Single combined master symbol-table |
|
||
|
|
| | | - Index of Global Hash Stream |
|
||
|
|
+--------------------+------------------------------+-------------------------------------------+
|
||
|
|
| TPI Hash Stream | - Contained in TPI Stream | - Hash table for looking up TPI records |
|
||
|
|
| | | by name |
|
||
|
|
+--------------------+------------------------------+-------------------------------------------+
|
||
|
|
| IPI Hash Stream | - Contained in IPI Stream | - Hash table for looking up IPI records |
|
||
|
|
| | | by name |
|
||
|
|
+--------------------+------------------------------+-------------------------------------------+
|
||
|
|
|
||
|
|
More information about the structure of each of these can be found on the
|
||
|
|
following pages:
|
||
|
|
|
||
|
|
:doc:`PdbStream`
|
||
|
|
Information about the PDB Info Stream and how it is used to match PDBs to EXEs.
|
||
|
|
|
||
|
|
:doc:`TpiStream`
|
||
|
|
Information about the TPI stream and the CodeView records contained within.
|
||
|
|
|
||
|
|
:doc:`DbiStream`
|
||
|
|
Information about the DBI stream and relevant substreams including the
|
||
|
|
Module Substreams, source file information, and CodeView symbol records
|
||
|
|
contained within.
|
||
|
|
|
||
|
|
:doc:`ModiStream`
|
||
|
|
Information about the Module Information Stream, of which there is one for
|
||
|
|
each compilation unit and the format of symbols contained within.
|
||
|
|
|
||
|
|
:doc:`PublicStream`
|
||
|
|
Information about the Public Symbol Stream.
|
||
|
|
|
||
|
|
:doc:`GlobalStream`
|
||
|
|
Information about the Global Symbol Stream.
|
||
|
|
|
||
|
|
:doc:`HashTable`
|
||
|
|
Information about the serialized hash table format used internally to
|
||
|
|
represent things such as the Named Stream Map and the Hash Adjusters in the
|
||
|
|
:doc:`TPI/IPI Stream <TpiStream>`.
|
||
|
|
|
||
|
|
CodeView
|
||
|
|
========
|
||
|
|
CodeView is another format which comes into the picture. While MSF defines
|
||
|
|
the structure of the overall file, and PDB defines the set of streams that
|
||
|
|
appear within the MSF file and the format of those streams, CodeView defines
|
||
|
|
the format of **symbol and type records** that appear within specific streams.
|
||
|
|
Refer to the pages on :doc:`CodeViewSymbols` and :doc:`CodeViewTypes` for
|
||
|
|
more information about the CodeView format.
|