Mercurial > hg > CbC > CbC_llvm

comparison tools/clang/docs/PCHInternals.rst @ 95:afa8332a0e37 LLVM3.8

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
LLVM 3.8
author Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
date Tue, 13 Oct 2015 17:48:58 +0900
parents 95c75e76d11b
children 1172e4bd9c6f
comparison
equal deleted inserted replaced
84:f3e34b893a5f 95:afa8332a0e37
122 section <pchinternals-chained>`. 122 section <pchinternals-chained>`.
123 123
124 AST File Contents 124 AST File Contents
125 ----------------- 125 -----------------
126 126
127 Clang's AST files are organized into several different blocks, each of which 127 An AST file produced by clang is an object file container with a ``clangast``
128 contains the serialized representation of a part of Clang's internal 128 (COFF) or ``__clangast`` (ELF and Mach-O) section containing the serialized AST.
129 Other target-specific sections in the object file container are used to hold
130 debug information for the data types defined in the AST. Tools built on top of
131 libclang that do not need debug information may also produce raw AST files that
132 only contain the serialized AST.
133
134 The ``clangast`` section is organized into several different blocks, each of
135 which contains the serialized representation of a part of Clang's internal
129 representation. Each of the blocks corresponds to either a block or a record 136 representation. Each of the blocks corresponds to either a block or a record
130 within `LLVM's bitstream format <http://llvm.org/docs/BitCodeFormat.html>`_. 137 within `LLVM's bitstream format <http://llvm.org/docs/BitCodeFormat.html>`_.
131 The contents of each of these logical blocks are described below. 138 The contents of each of these logical blocks are described below.
132 139
133 .. image:: PCHLayout.png 140 .. image:: PCHLayout.png
134 141
135 For a given AST file, the `llvm-bcanalyzer 142 The ``llvm-objdump`` utility provides a ``-raw-clang-ast`` option to extract the
136 <http://llvm.org/docs/CommandGuide/llvm-bcanalyzer.html>`_ utility can be used 143 binary contents of the AST section from an object file container.
137 to examine the actual structure of the bitstream for the AST file. This 144
138 information can be used both to help understand the structure of the AST file 145 The `llvm-bcanalyzer <http://llvm.org/docs/CommandGuide/llvm-bcanalyzer.html>`_
139 and to isolate areas where AST files can still be optimized, e.g., through the 146 utility can be used to examine the actual structure of the bitstream for the AST
140 introduction of abbreviations. 147 section. This information can be used both to help understand the structure of
148 the AST section and to isolate areas where the AST representation can still be
149 optimized, e.g., through the introduction of abbreviations.
150
141 151
142 Metadata Block 152 Metadata Block
143 ^^^^^^^^^^^^^^ 153 ^^^^^^^^^^^^^^
144 154
145 The metadata block contains several records that provide information about how 155 The metadata block contains several records that provide information about how