forked from OSchip/llvm-project
81 lines
3.0 KiB
ReStructuredText
81 lines
3.0 KiB
ReStructuredText
=====================================
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The Module Information Stream
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=====================================
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.. contents::
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:local:
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.. _modi_stream_intro:
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Introduction
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============
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The Module Info Stream (henceforth referred to as the Modi stream) contains
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information about a single module (object file, import library, etc that
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contributes to the binary this PDB contains debug information about. There
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is one modi stream for each module, and the mapping between modi stream index
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and module is contained in the :doc:`DBI Stream <DbiStream>`. The modi stream
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for a single module contains line information for the compiland, as well as
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all CodeView information for the symbols defined in the compiland. Finally,
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there is a "global refs" substream which is not well understood.
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.. _modi_stream_layout:
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Stream Layout
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=============
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A modi stream is laid out as follows:
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.. code-block:: c++
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struct ModiStream {
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uint32_t Signature;
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uint8_t Symbols[SymbolSize-4];
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uint8_t C11LineInfo[C11Size];
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uint8_t C13LineInfo[C13Size];
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uint32_t GlobalRefsSize;
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uint8_t GlobalRefs[GlobalRefsSize];
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};
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- **Signature** - Unknown. In practice only the value of ``4`` has been
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observed. It is hypothesized that this value corresponds to the set of
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``CV_SIGNATURE_xx`` defines in ``cvinfo.h``, with the value of ``4``
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meaning that this module has C13 line information (as opposed to C11 line
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information). A corollary of this is that we expect to only ever see
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C13 line info, and that we do not understand the format of C11 line info.
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- **Symbols** - The :ref:`CodeView Symbol Substream <modi_symbol_substream>`.
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``SymbolSize`` is equal to the value of ``SymByteSize`` for the
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corresponding module's entry in the :ref:`Module Info Substream
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<dbi_mod_info_substream>` of the :doc:`DBI Stream <DbiStream>`.
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- **C11LineInfo** - A block containing CodeView line information in C11
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format. ``C11Size`` is equal to the value of ``C11ByteSize`` from the
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:ref:`Module Info Substream <dbi_mod_info_substream>` of the
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:doc:`DBI Stream <DbiStream>`. If this value is ``0``, then C11 line
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information is not present. As mentioned previously, the format of
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C11 line info is not understood and we assume all line in modern PDBs
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to be in C13 format.
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- **C13LineInfo** - A block containing CodeView line information in C13
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format. ``C13Size`` is equal to the value of ``C13ByteSize`` from the
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:ref:`Module Info Substream <dbi_mod_info_substream>` of the
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:doc:`DBI Stream <DbiStream>`. If this value is ``0``, then C13 line
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information is not present.
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- **GlobalRefs** - The meaning of this substream is not understood.
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.. _modi_symbol_substream:
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The CodeView Symbol Substream
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=============================
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The CodeView Symbol Substream. This is an array of variable length
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records describing the functions, variables, inlining information,
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and other symbols defined in the compiland. The entire array consumes
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``SymbolSize-4`` bytes. The format of a CodeView Symbol Record (and
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thusly, an array of CodeView Symbol Records) is described in
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:doc:`CodeViewSymbols`.
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