<li><a href="#functiondefs">Function Definition</a></li>
<li><a href="#compactiontable">Compaction Table</a></li>
<li><a href="#instructionlist">Instruction List</a></li>
+ <li><a href="#opcodes">Instruction Opcodes</a></li>
<li><a href="#symtab">Symbol Table</a></li>
</ol>
</li>
other blocks because there is no identifier and no block length at the start
of the block. Essentially, this block is just the "magic number" for the file.
</p>
+<p>There are two types of signatures for LLVM bytecode: uncompressed and
+compressed as shown in the table below. </p>
<table>
<tbody>
<tr>
<th><b>Type</b></th>
- <th class="td_left"><b>Field Description</b></th>
+ <th class="td_left"><b>Uncompressed</b></th>
+ <th class="td_left"><b>Compressed</b></th>
</tr>
<tr>
<td><a href="#char">char</a></td>
<td class="td_left">Constant "l" (0x6C)</td>
+ <td class="td_left">Constant "l" (0x6C)</td>
</tr>
<tr>
<td><a href="#char">char</a></td>
<td class="td_left">Constant "l" (0x6C)</td>
+ <td class="td_left">Constant "l" (0x6C)</td>
</tr>
<tr>
<td><a href="#char">char</a></td>
<td class="td_left">Constant "v" (0x76)</td>
+ <td class="td_left">Constant "v" (0x76)</td>
</tr>
<tr>
<td><a href="#char">char</a></td>
<td class="td_left">Constant "m" (0x6D)</td>
+ <td class="td_left">Constant "c" (0x63)</td>
+ </tr>
+ <tr>
+ <td><a href="#char">char</a></td>
+ <td class="td_left">N/A</td>
+ <td class="td_left">'0'=null,'1'=gzip,'2'=bzip2</td>
</tr>
</tbody>
</table>
+<p>In other words, the uncompressed signature is just the characters 'llvm'
+while the compressed signature is the characters 'llvc' followed by an ascii
+digit ('0', '1', or '2') that indicates the kind of compression used. A value of
+'0' indicates that null compression was used. This can happen when compression
+was requested on a platform that wasn't configured for gzip or bzip2. A value of
+'1' means that the rest of the file is compressed using the gzip algorithm and
+should be uncompressed before interpretation. A value of '2' means that the rest
+of the file is compressed using the bzip2 algorithm and should be uncompressed
+before interpretation. In all cases, the data resulting from uncompression
+should be interpreted as if it occurred immediately after the 'llvm'
+signature (i.e. the uncompressed data begins with the
+<a href="#module">Module Block</a></p>
+<p><b>NOTE:</b> As of LLVM 1.4, all bytecode files produced by the LLVM tools
+are compressed by default. To disable compression, pass the
+<tt>--disable-compression</tt> option to the tool, if it supports it.
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsection"><a name="module">Module Block</a> </div>
definitions occurring in the module.</td>
</tr>
<tr>
- <td><a href="#zlist">zlist</a>(<a href="#uint24_vbr">uint24_vbr</a>)</td>
- <td class="td_left">A zero terminated list of function types
+ <td><a href="#zlist">zlist</a>(<a href="#funcfield">funcfield</a>)</td>
+ <td class="td_left">A zero terminated list of function definitions
occurring in the module.</td>
</tr>
<tr>
</tbody>
</table>
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"><a name="globalvar">Global Variable Field</a>
</div>
</tbody>
</table>
</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"><a name="funcfield">Function Field</a>
+</div>
+<div class="doc_text">
+<p>Functions are written using an <a href="#uint32_vbr">uint32_vbr</a>
+that encodes information about the function and a set of flags.</p>
+
+<p>The table below provides the bit layout of the <a
+href="#uint32_vbr">uint32_vbr</a> that describes the function.</p>
+
+<table>
+ <tbody>
+ <tr>
+ <th><b>Type</b></th>
+ <th class="td_left"><b>Description</b></th>
+ </tr>
+ <tr>
+ <td><a href="#bit">bit(0-3)</a></td>
+ <td class="td_left">Reserved for future use. Currently set to 0001.</td>
+ </tr>
+ <tr>
+ <td><a href="#bit">bit(4)</a></td>
+ <td class="td_left">If this bit is set to 1, the indicated function is
+ external, and there is no <a href="#functiondefs">Function Definiton
+ Block</a> in the bytecode file for the function.</td>
+ </tr>
+ <tr>
+ <td><a href="#bit">bit(5-)</a></td>
+ <td class="td_left">Type slot number of type for the function.</td>
+ </tr>
+ </tbody>
+</table>
+
+</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsection"><a name="constantpool">Constant Pool</a> </div>
<div class="doc_text">
href="#uint32_vbr">uint32_vbr</a> encoded value slot numbers to the constant
field values of the structure.</li>
</ul>
-<p>When the number of operands to the constant is non-zero, we have a
-constant expression and its field format is provided in the table below.</p>
+
+<p>When the number of operands to the constant is one, we have an 'undef' value
+of the specified type.</p>
+
+<p>When the number of operands to the constant is greater than one, we have a
+constant expression and its field format is provided in the table below, and the
+number is equal to the number of operands+1.</p>
<table>
<tbody>
<tr>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"><a name="opcodes">Opcodes</a></div>
+<div class="doc_subsection"><a name="opcodes">Instruction Opcodes</a></div>
<div class="doc_text">
<p>Instructions encode an opcode that identifies the kind of instruction.
Opcodes are an enumerated integer value. The specific values used depend on
the version of LLVM you're using. The opcode values are defined in the
- <a href="http://llvm.org/cvsweb/cvsweb.cgi/llvm/include/llvm/Instruction.def">
+ <a href="http://llvm.cs.uiuc.edu/cvsweb/cvsweb.cgi/llvm/include/llvm/Instruction.def">
<tt>include/llvm/Instruction.def</tt></a> file. You should check there for the
most recent definitions. The table below provides the opcodes defined as of
the writing of this document. The table associates each opcode mnemonic with
<tr><td>Switch</td><td>3</td><td>1</td><td>1.0</td></tr>
<tr><td>Invoke</td><td>4</td><td>1</td><td>1.0</td></tr>
<tr><td>Unwind</td><td>5</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Unreachable</td><td>6</td><td>1</td><td>1.4</td></tr>
<tr><td colspan="4"><b>Binary Operators</b></td></tr>
- <tr><td>Add</td><td>6</td><td>1</td><td>1.0</td></tr>
- <tr><td>Sub</td><td>7</td><td>1</td><td>1.0</td></tr>
- <tr><td>Mul</td><td>8</td><td>1</td><td>1.0</td></tr>
- <tr><td>Div</td><td>9</td><td>1</td><td>1.0</td></tr>
- <tr><td>Rem</td><td>10</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Add</td><td>7</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Sub</td><td>8</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Mul</td><td>9</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Div</td><td>10</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Rem</td><td>11</td><td>1</td><td>1.0</td></tr>
<tr><td colspan="4"><b>Logical Operators</b></td></tr>
- <tr><td>And</td><td>11</td><td>1</td><td>1.0</td></tr>
- <tr><td>Or</td><td>12</td><td>1</td><td>1.0</td></tr>
- <tr><td>Xor</td><td>13</td><td>1</td><td>1.0</td></tr>
+ <tr><td>And</td><td>12</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Or</td><td>13</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Xor</td><td>14</td><td>1</td><td>1.0</td></tr>
<tr><td colspan="4"><b>Binary Comparison Operators</b></td></tr>
- <tr><td>SetEQ</td><td>14</td><td>1</td><td>1.0</td></tr>
- <tr><td>SetNE</td><td>15</td><td>1</td><td>1.0</td></tr>
- <tr><td>SetLE</td><td>16</td><td>1</td><td>1.0</td></tr>
- <tr><td>SetGE</td><td>17</td><td>1</td><td>1.0</td></tr>
- <tr><td>SetLT</td><td>18</td><td>1</td><td>1.0</td></tr>
- <tr><td>SetGT</td><td>19</td><td>1</td><td>1.0</td></tr>
+ <tr><td>SetEQ</td><td>15</td><td>1</td><td>1.0</td></tr>
+ <tr><td>SetNE</td><td>16</td><td>1</td><td>1.0</td></tr>
+ <tr><td>SetLE</td><td>17</td><td>1</td><td>1.0</td></tr>
+ <tr><td>SetGE</td><td>18</td><td>1</td><td>1.0</td></tr>
+ <tr><td>SetLT</td><td>19</td><td>1</td><td>1.0</td></tr>
+ <tr><td>SetGT</td><td>20</td><td>1</td><td>1.0</td></tr>
<tr><td colspan="4"><b>Memory Operators</b></td></tr>
- <tr><td>Malloc</td><td>20</td><td>1</td><td>1.0</td></tr>
- <tr><td>Free</td><td>21</td><td>1</td><td>1.0</td></tr>
- <tr><td>Alloca</td><td>22</td><td>1</td><td>1.0</td></tr>
- <tr><td>Load</td><td>23</td><td>1</td><td>1.0</td></tr>
- <tr><td>Store</td><td>24</td><td>1</td><td>1.0</td></tr>
- <tr><td>GetElementPtr</td><td>25</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Malloc</td><td>21</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Free</td><td>22</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Alloca</td><td>23</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Load</td><td>24</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Store</td><td>25</td><td>1</td><td>1.0</td></tr>
+ <tr><td>GetElementPtr</td><td>26</td><td>1</td><td>1.0</td></tr>
<tr><td colspan="4"><b>Other Operators</b></td></tr>
- <tr><td>PHI</td><td>26</td><td>1</td><td>1.0</td></tr>
- <tr><td>Cast</td><td>27</td><td>1</td><td>1.0</td></tr>
- <tr><td>Call</td><td>28</td><td>1</td><td>1.0</td></tr>
- <tr><td>Shl</td><td>29</td><td>1</td><td>1.0</td></tr>
- <tr><td>Shr</td><td>30</td><td>1</td><td>1.0</td></tr>
- <tr><td>VANext</td><td>31</td><td>1</td><td>1.0</td></tr>
- <tr><td>VAArg</td><td>32</td><td>1</td><td>1.0</td></tr>
- <tr><td>Select</td><td>33</td><td>2</td><td>1.2</td></tr>
- <tr><td>UserOp1</td><td>34</td><td>1</td><td>1.0</td></tr>
- <tr><td>UserOp2</td><td>35</td><td>1</td><td>1.0</td></tr>
+ <tr><td>PHI</td><td>27</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Cast</td><td>28</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Call</td><td>29</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Shl</td><td>30</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Shr</td><td>31</td><td>1</td><td>1.0</td></tr>
+ <tr><td>VANext</td><td>32</td><td>1</td><td>1.0</td></tr>
+ <tr><td>VAArg</td><td>33</td><td>1</td><td>1.0</td></tr>
+ <tr><td>Select</td><td>34</td><td>2</td><td>1.2</td></tr>
+ <tr><td>UserOp1</td><td>35</td><td>1</td><td>1.0</td></tr>
+ <tr><td>UserOp2</td><td>36</td><td>1</td><td>1.0</td></tr>
</tbody>
</table>
</div>
describes the differences between that version and the one that <i>follows</i>.
</p>
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsection"><a name="vers13">Version 1.3 Differences From
1.4</a></div>
<!-- _______________________________________________________________________ -->
+
+<div class="doc_subsubsection">Unreachable Instruction</div>
+<div class="doc_text">
+ <p>The LLVM <a href="LangRef.html#i_unreachable">Unreachable</a> instruction
+ was added in version 1.4 of LLVM. This caused all instruction numbers after
+ it to shift down by one.</p>
+</div>
+
+<div class="doc_subsubsection">Function Flags</div>
+<div class="doc_text">
+ <p>LLVM bytecode versions prior to 1.4 did not include the 5 bit offset
+ in <a href="#funcfield">the function list</a> in the <a
+ href="#globalinfo">Module Global Info</a> block.</p>
+</div>
+
+<div class="doc_subsubsection">Function Flags</div>
+<div class="doc_text">
+ <p>LLVM bytecode versions prior to 1.4 did not include the 'undef' constant
+ value, which affects the encoding of <a href="#constant">Constant
+ Fields</a>.</p>
+</div>
+
+<!--
<div class="doc_subsubsection">Aligned Data</div>
<div class="doc_text">
<p>In version 1.3, certain data items were aligned to 32-bit boundaries. In
</ul>
<p>None of these constructs are aligned in version 1.4</p>
</div>
+-->
<!-- _______________________________________________________________________ -->
<div class="doc_subsection"><a name="vers12">Version 1.2 Differences
From 1.3</a></div>
<!-- _______________________________________________________________________ -->
+
<div class="doc_subsubsection">Type Derives From Value</div>
<div class="doc_text">
<p>In version 1.2, the Type class in the LLVM IR derives from the Value
projects / oota-llvm.git / blobdiff