Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 1 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" |
| 2 | "http://www.w3.org/TR/html4/strict.dtd"> |
| 3 | <html> |
| 4 | <head> |
| 5 | <title>Extending LLVM: Adding instructions, intrinsics, types, etc.</title> |
| 6 | <link rel="stylesheet" href="llvm.css" type="text/css"> |
| 7 | </head> |
| 8 | |
| 9 | <body> |
| 10 | |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 11 | <h1> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 12 | Extending LLVM: Adding instructions, intrinsics, types, etc. |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 13 | </h1> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 14 | |
| 15 | <ol> |
| 16 | <li><a href="#introduction">Introduction and Warning</a></li> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 17 | <li><a href="#intrinsic">Adding a new intrinsic function</a></li> |
Chris Lattner | 3636540 | 2004-04-09 19:24:20 +0000 | [diff] [blame] | 18 | <li><a href="#instruction">Adding a new instruction</a></li> |
Nate Begeman | 099d76c | 2006-01-16 07:54:23 +0000 | [diff] [blame] | 19 | <li><a href="#sdnode">Adding a new SelectionDAG node</a></li> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 20 | <li><a href="#type">Adding a new type</a> |
| 21 | <ol> |
| 22 | <li><a href="#fund_type">Adding a new fundamental type</a></li> |
| 23 | <li><a href="#derived_type">Adding a new derived type</a></li> |
| 24 | </ol></li> |
| 25 | </ol> |
| 26 | |
Chris Lattner | 7911ce2 | 2004-05-23 21:07:27 +0000 | [diff] [blame] | 27 | <div class="doc_author"> |
Chris Lattner | 5eb9f0d | 2005-05-11 03:53:53 +0000 | [diff] [blame] | 28 | <p>Written by <a href="http://misha.brukman.net">Misha Brukman</a>, |
Chris Lattner | b5f6e25 | 2006-01-16 16:31:40 +0000 | [diff] [blame] | 29 | Brad Jones, Nate Begeman, |
| 30 | and <a href="http://nondot.org/sabre">Chris Lattner</a></p> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 31 | </div> |
| 32 | |
| 33 | <!-- *********************************************************************** --> |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 34 | <h2> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 35 | <a name="introduction">Introduction and Warning</a> |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 36 | </h2> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 37 | <!-- *********************************************************************** --> |
| 38 | |
NAKAMURA Takumi | f5af6ad | 2011-04-23 00:30:22 +0000 | [diff] [blame] | 39 | <div> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 40 | |
| 41 | <p>During the course of using LLVM, you may wish to customize it for your |
| 42 | research project or for experimentation. At this point, you may realize that |
| 43 | you need to add something to LLVM, whether it be a new fundamental type, a new |
| 44 | intrinsic function, or a whole new instruction.</p> |
| 45 | |
| 46 | <p>When you come to this realization, stop and think. Do you really need to |
| 47 | extend LLVM? Is it a new fundamental capability that LLVM does not support at |
| 48 | its current incarnation or can it be synthesized from already pre-existing LLVM |
| 49 | elements? If you are not sure, ask on the <a |
| 50 | href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM-dev</a> list. The |
| 51 | reason is that extending LLVM will get involved as you need to update all the |
| 52 | different passes that you intend to use with your extension, and there are |
| 53 | <em>many</em> LLVM analyses and transformations, so it may be quite a bit of |
| 54 | work.</p> |
| 55 | |
Chris Lattner | 35dd5b0 | 2006-04-12 17:42:39 +0000 | [diff] [blame] | 56 | <p>Adding an <a href="#intrinsic">intrinsic function</a> is far easier than |
| 57 | adding an instruction, and is transparent to optimization passes. If your added |
| 58 | functionality can be expressed as a |
Misha Brukman | b3b2827 | 2004-04-06 04:17:51 +0000 | [diff] [blame] | 59 | function call, an intrinsic function is the method of choice for LLVM |
| 60 | extension.</p> |
| 61 | |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 62 | <p>Before you invest a significant amount of effort into a non-trivial |
| 63 | extension, <span class="doc_warning">ask on the list</span> if what you are |
| 64 | looking to do can be done with already-existing infrastructure, or if maybe |
| 65 | someone else is already working on it. You will save yourself a lot of time and |
| 66 | effort by doing so.</p> |
| 67 | |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 68 | </div> |
| 69 | |
| 70 | <!-- *********************************************************************** --> |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 71 | <h2> |
Chris Lattner | 3636540 | 2004-04-09 19:24:20 +0000 | [diff] [blame] | 72 | <a name="intrinsic">Adding a new intrinsic function</a> |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 73 | </h2> |
Chris Lattner | 3636540 | 2004-04-09 19:24:20 +0000 | [diff] [blame] | 74 | <!-- *********************************************************************** --> |
| 75 | |
NAKAMURA Takumi | f5af6ad | 2011-04-23 00:30:22 +0000 | [diff] [blame] | 76 | <div> |
Chris Lattner | 3636540 | 2004-04-09 19:24:20 +0000 | [diff] [blame] | 77 | |
| 78 | <p>Adding a new intrinsic function to LLVM is much easier than adding a new |
| 79 | instruction. Almost all extensions to LLVM should start as an intrinsic |
| 80 | function and then be turned into an instruction if warranted.</p> |
| 81 | |
| 82 | <ol> |
| 83 | <li><tt>llvm/docs/LangRef.html</tt>: |
| 84 | Document the intrinsic. Decide whether it is code generator specific and |
| 85 | what the restrictions are. Talk to other people about it so that you are |
| 86 | sure it's a good idea.</li> |
| 87 | |
Chris Lattner | 35dd5b0 | 2006-04-12 17:42:39 +0000 | [diff] [blame] | 88 | <li><tt>llvm/include/llvm/Intrinsics*.td</tt>: |
| 89 | Add an entry for your intrinsic. Describe its memory access characteristics |
Reid Spencer | c8d0636 | 2007-04-01 07:44:52 +0000 | [diff] [blame] | 90 | for optimization (this controls whether it will be DCE'd, CSE'd, etc). Note |
| 91 | that any intrinsic using the <tt>llvm_int_ty</tt> type for an argument will |
| 92 | be deemed by <tt>tblgen</tt> as overloaded and the corresponding suffix |
| 93 | will be required on the intrinsic's name.</li> |
Chris Lattner | 0190fdb | 2004-04-10 06:56:53 +0000 | [diff] [blame] | 94 | |
Nate Begeman | 2f86c22 | 2006-01-14 01:27:10 +0000 | [diff] [blame] | 95 | <li><tt>llvm/lib/Analysis/ConstantFolding.cpp</tt>: If it is possible to |
| 96 | constant fold your intrinsic, add support to it in the |
| 97 | <tt>canConstantFoldCallTo</tt> and <tt>ConstantFoldCall</tt> functions.</li> |
| 98 | |
Nate Begeman | 099d76c | 2006-01-16 07:54:23 +0000 | [diff] [blame] | 99 | <li><tt>llvm/test/Regression/*</tt>: Add test cases for your test cases to the |
| 100 | test suite</li> |
Chris Lattner | 3636540 | 2004-04-09 19:24:20 +0000 | [diff] [blame] | 101 | </ol> |
| 102 | |
Chris Lattner | 5eb9f0d | 2005-05-11 03:53:53 +0000 | [diff] [blame] | 103 | <p>Once the intrinsic has been added to the system, you must add code generator |
| 104 | support for it. Generally you must do the following steps:</p> |
| 105 | |
| 106 | <dl> |
| 107 | <dt>Add support to the C backend in <tt>lib/Target/CBackend/</tt></dt> |
| 108 | |
Nate Begeman | 099d76c | 2006-01-16 07:54:23 +0000 | [diff] [blame] | 109 | <dd>Depending on the intrinsic, there are a few ways to implement this. For |
Bill Wendling | 068da27 | 2007-09-22 10:07:00 +0000 | [diff] [blame] | 110 | most intrinsics, it makes sense to add code to lower your intrinsic in |
| 111 | <tt>LowerIntrinsicCall</tt> in <tt>lib/CodeGen/IntrinsicLowering.cpp</tt>. |
| 112 | Second, if it makes sense to lower the intrinsic to an expanded sequence of |
| 113 | C code in all cases, just emit the expansion in <tt>visitCallInst</tt> in |
| 114 | <tt>Writer.cpp</tt>. If the intrinsic has some way to express it with GCC |
| 115 | (or any other compiler) extensions, it can be conditionally supported based |
| 116 | on the compiler compiling the CBE output (see <tt>llvm.prefetch</tt> for an |
| 117 | example). Third, if the intrinsic really has no way to be lowered, just |
| 118 | have the code generator emit code that prints an error message and calls |
| 119 | abort if executed.</dd> |
Chris Lattner | 5eb9f0d | 2005-05-11 03:53:53 +0000 | [diff] [blame] | 120 | |
Chris Lattner | 35dd5b0 | 2006-04-12 17:42:39 +0000 | [diff] [blame] | 121 | <dt>Add support to the .td file for the target(s) of your choice in |
| 122 | <tt>lib/Target/*/*.td</tt>.</dt> |
Chris Lattner | 5eb9f0d | 2005-05-11 03:53:53 +0000 | [diff] [blame] | 123 | |
Chris Lattner | 35dd5b0 | 2006-04-12 17:42:39 +0000 | [diff] [blame] | 124 | <dd>This is usually a matter of adding a pattern to the .td file that matches |
| 125 | the intrinsic, though it may obviously require adding the instructions you |
| 126 | want to generate as well. There are lots of examples in the PowerPC and X86 |
| 127 | backend to follow.</dd> |
Bill Wendling | 068da27 | 2007-09-22 10:07:00 +0000 | [diff] [blame] | 128 | </dl> |
Chris Lattner | 5eb9f0d | 2005-05-11 03:53:53 +0000 | [diff] [blame] | 129 | |
Nate Begeman | 099d76c | 2006-01-16 07:54:23 +0000 | [diff] [blame] | 130 | </div> |
Chris Lattner | 5eb9f0d | 2005-05-11 03:53:53 +0000 | [diff] [blame] | 131 | |
Nate Begeman | 099d76c | 2006-01-16 07:54:23 +0000 | [diff] [blame] | 132 | <!-- *********************************************************************** --> |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 133 | <h2> |
Nate Begeman | 099d76c | 2006-01-16 07:54:23 +0000 | [diff] [blame] | 134 | <a name="sdnode">Adding a new SelectionDAG node</a> |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 135 | </h2> |
Nate Begeman | 099d76c | 2006-01-16 07:54:23 +0000 | [diff] [blame] | 136 | <!-- *********************************************************************** --> |
Chris Lattner | 5eb9f0d | 2005-05-11 03:53:53 +0000 | [diff] [blame] | 137 | |
NAKAMURA Takumi | f5af6ad | 2011-04-23 00:30:22 +0000 | [diff] [blame] | 138 | <div> |
Chris Lattner | 5eb9f0d | 2005-05-11 03:53:53 +0000 | [diff] [blame] | 139 | |
Nate Begeman | 099d76c | 2006-01-16 07:54:23 +0000 | [diff] [blame] | 140 | <p>As with intrinsics, adding a new SelectionDAG node to LLVM is much easier |
| 141 | than adding a new instruction. New nodes are often added to help represent |
| 142 | instructions common to many targets. These nodes often map to an LLVM |
| 143 | instruction (add, sub) or intrinsic (byteswap, population count). In other |
| 144 | cases, new nodes have been added to allow many targets to perform a common task |
| 145 | (converting between floating point and integer representation) or capture more |
| 146 | complicated behavior in a single node (rotate).</p> |
Chris Lattner | 5eb9f0d | 2005-05-11 03:53:53 +0000 | [diff] [blame] | 147 | |
Nate Begeman | 099d76c | 2006-01-16 07:54:23 +0000 | [diff] [blame] | 148 | <ol> |
| 149 | <li><tt>include/llvm/CodeGen/SelectionDAGNodes.h</tt>: |
| 150 | Add an enum value for the new SelectionDAG node.</li> |
| 151 | <li><tt>lib/CodeGen/SelectionDAG/SelectionDAG.cpp</tt>: |
| 152 | Add code to print the node to <tt>getOperationName</tt>. If your new node |
| 153 | can be evaluated at compile time when given constant arguments (such as an |
| 154 | add of a constant with another constant), find the <tt>getNode</tt> method |
| 155 | that takes the appropriate number of arguments, and add a case for your node |
| 156 | to the switch statement that performs constant folding for nodes that take |
| 157 | the same number of arguments as your new node.</li> |
| 158 | <li><tt>lib/CodeGen/SelectionDAG/LegalizeDAG.cpp</tt>: |
| 159 | Add code to <a href="CodeGenerator.html#selectiondag_legalize">legalize, |
| 160 | promote, and expand</a> the node as necessary. At a minimum, you will need |
| 161 | to add a case statement for your node in <tt>LegalizeOp</tt> which calls |
| 162 | LegalizeOp on the node's operands, and returns a new node if any of the |
| 163 | operands changed as a result of being legalized. It is likely that not all |
| 164 | targets supported by the SelectionDAG framework will natively support the |
| 165 | new node. In this case, you must also add code in your node's case |
| 166 | statement in <tt>LegalizeOp</tt> to Expand your node into simpler, legal |
Chris Lattner | b5f6e25 | 2006-01-16 16:31:40 +0000 | [diff] [blame] | 167 | operations. The case for <tt>ISD::UREM</tt> for expanding a remainder into |
| 168 | a divide, multiply, and a subtract is a good example.</li> |
Nate Begeman | 099d76c | 2006-01-16 07:54:23 +0000 | [diff] [blame] | 169 | <li><tt>lib/CodeGen/SelectionDAG/LegalizeDAG.cpp</tt>: |
| 170 | If targets may support the new node being added only at certain sizes, you |
| 171 | will also need to add code to your node's case statement in |
| 172 | <tt>LegalizeOp</tt> to Promote your node's operands to a larger size, and |
| 173 | perform the correct operation. You will also need to add code to |
Chris Lattner | b5f6e25 | 2006-01-16 16:31:40 +0000 | [diff] [blame] | 174 | <tt>PromoteOp</tt> to do this as well. For a good example, see |
| 175 | <tt>ISD::BSWAP</tt>, |
Nate Begeman | 099d76c | 2006-01-16 07:54:23 +0000 | [diff] [blame] | 176 | which promotes its operand to a wider size, performs the byteswap, and then |
| 177 | shifts the correct bytes right to emulate the narrower byteswap in the |
| 178 | wider type.</li> |
| 179 | <li><tt>lib/CodeGen/SelectionDAG/LegalizeDAG.cpp</tt>: |
| 180 | Add a case for your node in <tt>ExpandOp</tt> to teach the legalizer how to |
| 181 | perform the action represented by the new node on a value that has been |
| 182 | split into high and low halves. This case will be used to support your |
| 183 | node with a 64 bit operand on a 32 bit target.</li> |
| 184 | <li><tt>lib/CodeGen/SelectionDAG/DAGCombiner.cpp</tt>: |
| 185 | If your node can be combined with itself, or other existing nodes in a |
| 186 | peephole-like fashion, add a visit function for it, and call that function |
| 187 | from <tt></tt>. There are several good examples for simple combines you |
| 188 | can do; <tt>visitFABS</tt> and <tt>visitSRL</tt> are good starting places. |
| 189 | </li> |
| 190 | <li><tt>lib/Target/PowerPC/PPCISelLowering.cpp</tt>: |
| 191 | Each target has an implementation of the <tt>TargetLowering</tt> class, |
| 192 | usually in its own file (although some targets include it in the same |
| 193 | file as the DAGToDAGISel). The default behavior for a target is to |
| 194 | assume that your new node is legal for all types that are legal for |
| 195 | that target. If this target does not natively support your node, then |
| 196 | tell the target to either Promote it (if it is supported at a larger |
| 197 | type) or Expand it. This will cause the code you wrote in |
| 198 | <tt>LegalizeOp</tt> above to decompose your new node into other legal |
| 199 | nodes for this target.</li> |
| 200 | <li><tt>lib/Target/TargetSelectionDAG.td</tt>: |
| 201 | Most current targets supported by LLVM generate code using the DAGToDAG |
| 202 | method, where SelectionDAG nodes are pattern matched to target-specific |
| 203 | nodes, which represent individual instructions. In order for the targets |
| 204 | to match an instruction to your new node, you must add a def for that node |
| 205 | to the list in this file, with the appropriate type constraints. Look at |
| 206 | <tt>add</tt>, <tt>bswap</tt>, and <tt>fadd</tt> for examples.</li> |
| 207 | <li><tt>lib/Target/PowerPC/PPCInstrInfo.td</tt>: |
| 208 | Each target has a tablegen file that describes the target's instruction |
| 209 | set. For targets that use the DAGToDAG instruction selection framework, |
| 210 | add a pattern for your new node that uses one or more target nodes. |
| 211 | Documentation for this is a bit sparse right now, but there are several |
| 212 | decent examples. See the patterns for <tt>rotl</tt> in |
| 213 | <tt>PPCInstrInfo.td</tt>.</li> |
| 214 | <li>TODO: document complex patterns.</li> |
| 215 | <li><tt>llvm/test/Regression/CodeGen/*</tt>: Add test cases for your new node |
| 216 | to the test suite. <tt>llvm/test/Regression/CodeGen/X86/bswap.ll</tt> is |
| 217 | a good example.</li> |
| 218 | </ol> |
Chris Lattner | 3636540 | 2004-04-09 19:24:20 +0000 | [diff] [blame] | 219 | |
| 220 | </div> |
| 221 | |
| 222 | <!-- *********************************************************************** --> |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 223 | <h2> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 224 | <a name="instruction">Adding a new instruction</a> |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 225 | </h2> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 226 | <!-- *********************************************************************** --> |
| 227 | |
NAKAMURA Takumi | f5af6ad | 2011-04-23 00:30:22 +0000 | [diff] [blame] | 228 | <div> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 229 | |
Gabor Greif | 04367bf | 2007-07-06 22:07:22 +0000 | [diff] [blame] | 230 | <p><span class="doc_warning">WARNING: adding instructions changes the bitcode |
Misha Brukman | b3b2827 | 2004-04-06 04:17:51 +0000 | [diff] [blame] | 231 | format, and it will take some effort to maintain compatibility with |
| 232 | the previous version.</span> Only add an instruction if it is absolutely |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 233 | necessary.</p> |
| 234 | |
| 235 | <ol> |
Misha Brukman | b3b2827 | 2004-04-06 04:17:51 +0000 | [diff] [blame] | 236 | |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 237 | <li><tt>llvm/include/llvm/Instruction.def</tt>: |
| 238 | add a number for your instruction and an enum name</li> |
| 239 | |
Misha Brukman | 47b14a4 | 2004-07-29 17:30:56 +0000 | [diff] [blame] | 240 | <li><tt>llvm/include/llvm/Instructions.h</tt>: |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 241 | add a definition for the class that will represent your instruction</li> |
| 242 | |
| 243 | <li><tt>llvm/include/llvm/Support/InstVisitor.h</tt>: |
| 244 | add a prototype for a visitor to your new instruction type</li> |
| 245 | |
| 246 | <li><tt>llvm/lib/AsmParser/Lexer.l</tt>: |
| 247 | add a new token to parse your instruction from assembly text file</li> |
| 248 | |
| 249 | <li><tt>llvm/lib/AsmParser/llvmAsmParser.y</tt>: |
| 250 | add the grammar on how your instruction can be read and what it will |
| 251 | construct as a result</li> |
| 252 | |
Gabor Greif | 04367bf | 2007-07-06 22:07:22 +0000 | [diff] [blame] | 253 | <li><tt>llvm/lib/Bitcode/Reader/Reader.cpp</tt>: |
| 254 | add a case for your instruction and how it will be parsed from bitcode</li> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 255 | |
| 256 | <li><tt>llvm/lib/VMCore/Instruction.cpp</tt>: |
| 257 | add a case for how your instruction will be printed out to assembly</li> |
| 258 | |
Chris Lattner | 8f36321 | 2004-07-29 17:31:57 +0000 | [diff] [blame] | 259 | <li><tt>llvm/lib/VMCore/Instructions.cpp</tt>: |
Misha Brukman | e39cd63 | 2004-09-28 16:58:12 +0000 | [diff] [blame] | 260 | implement the class you defined in |
| 261 | <tt>llvm/include/llvm/Instructions.h</tt></li> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 262 | |
Misha Brukman | a424228 | 2004-12-01 20:58:54 +0000 | [diff] [blame] | 263 | <li>Test your instruction</li> |
| 264 | |
| 265 | <li><tt>llvm/lib/Target/*</tt>: |
| 266 | Add support for your instruction to code generators, or add a lowering |
| 267 | pass.</li> |
| 268 | |
| 269 | <li><tt>llvm/test/Regression/*</tt>: add your test cases to the test suite.</li> |
| 270 | |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 271 | </ol> |
| 272 | |
| 273 | <p>Also, you need to implement (or modify) any analyses or passes that you want |
| 274 | to understand this new instruction.</p> |
| 275 | |
| 276 | </div> |
| 277 | |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 278 | |
| 279 | <!-- *********************************************************************** --> |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 280 | <h2> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 281 | <a name="type">Adding a new type</a> |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 282 | </h2> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 283 | <!-- *********************************************************************** --> |
| 284 | |
NAKAMURA Takumi | f5af6ad | 2011-04-23 00:30:22 +0000 | [diff] [blame] | 285 | <div> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 286 | |
Gabor Greif | 04367bf | 2007-07-06 22:07:22 +0000 | [diff] [blame] | 287 | <p><span class="doc_warning">WARNING: adding new types changes the bitcode |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 288 | format, and will break compatibility with currently-existing LLVM |
| 289 | installations.</span> Only add new types if it is absolutely necessary.</p> |
| 290 | |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 291 | <!-- ======================================================================= --> |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 292 | <h3> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 293 | <a name="fund_type">Adding a fundamental type</a> |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 294 | </h3> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 295 | |
NAKAMURA Takumi | f5af6ad | 2011-04-23 00:30:22 +0000 | [diff] [blame] | 296 | <div> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 297 | |
| 298 | <ol> |
| 299 | |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 300 | <li><tt>llvm/include/llvm/Type.h</tt>: |
Chris Lattner | 55f9501 | 2005-04-23 21:59:11 +0000 | [diff] [blame] | 301 | add enum for the new type; add static <tt>Type*</tt> for this type</li> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 302 | |
| 303 | <li><tt>llvm/lib/VMCore/Type.cpp</tt>: |
| 304 | add mapping from <tt>TypeID</tt> => <tt>Type*</tt>; |
| 305 | initialize the static <tt>Type*</tt></li> |
| 306 | |
| 307 | <li><tt>llvm/lib/AsmReader/Lexer.l</tt>: |
| 308 | add ability to parse in the type from text assembly</li> |
| 309 | |
| 310 | <li><tt>llvm/lib/AsmReader/llvmAsmParser.y</tt>: |
| 311 | add a token for that type</li> |
| 312 | |
| 313 | </ol> |
| 314 | |
| 315 | </div> |
| 316 | |
| 317 | <!-- ======================================================================= --> |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 318 | <h3> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 319 | <a name="derived_type">Adding a derived type</a> |
NAKAMURA Takumi | 05d0265 | 2011-04-18 23:59:50 +0000 | [diff] [blame] | 320 | </h3> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 321 | |
NAKAMURA Takumi | f5af6ad | 2011-04-23 00:30:22 +0000 | [diff] [blame] | 322 | <div> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 323 | |
Chris Lattner | 8dad40c | 2004-08-12 19:06:24 +0000 | [diff] [blame] | 324 | <ol> |
Chris Lattner | 8dad40c | 2004-08-12 19:06:24 +0000 | [diff] [blame] | 325 | <li><tt>llvm/include/llvm/Type.h</tt>: |
Chris Lattner | 55f9501 | 2005-04-23 21:59:11 +0000 | [diff] [blame] | 326 | add enum for the new type; add a forward declaration of the type |
Misha Brukman | 7cc8a89 | 2004-08-12 19:58:43 +0000 | [diff] [blame] | 327 | also</li> |
Chris Lattner | 8dad40c | 2004-08-12 19:06:24 +0000 | [diff] [blame] | 328 | |
Chris Lattner | 47746aa | 2005-11-13 02:09:55 +0000 | [diff] [blame] | 329 | <li><tt>llvm/include/llvm/DerivedTypes.h</tt>: |
Chris Lattner | 8dad40c | 2004-08-12 19:06:24 +0000 | [diff] [blame] | 330 | add new class to represent new class in the hierarchy; add forward |
| 331 | declaration to the TypeMap value type</li> |
| 332 | |
| 333 | <li><tt>llvm/lib/VMCore/Type.cpp</tt>: |
| 334 | add support for derived type to: |
Misha Brukman | 7cc8a89 | 2004-08-12 19:58:43 +0000 | [diff] [blame] | 335 | <div class="doc_code"> |
| 336 | <pre> |
| 337 | std::string getTypeDescription(const Type &Ty, |
| 338 | std::vector<const Type*> &TypeStack) |
| 339 | bool TypesEqual(const Type *Ty, const Type *Ty2, |
| 340 | std::map<const Type*, const Type*> & EqTypes) |
| 341 | </pre> |
| 342 | </div> |
| 343 | add necessary member functions for type, and factory methods</li> |
Chris Lattner | 8dad40c | 2004-08-12 19:06:24 +0000 | [diff] [blame] | 344 | |
| 345 | <li><tt>llvm/lib/AsmReader/Lexer.l</tt>: |
| 346 | add ability to parse in the type from text assembly</li> |
| 347 | |
Gabor Greif | 04367bf | 2007-07-06 22:07:22 +0000 | [diff] [blame] | 348 | <li><tt>llvm/lib/BitCode/Writer/Writer.cpp</tt>: |
| 349 | modify <tt>void BitcodeWriter::outputType(const Type *T)</tt> to serialize |
Misha Brukman | 7cc8a89 | 2004-08-12 19:58:43 +0000 | [diff] [blame] | 350 | your type</li> |
Chris Lattner | 8dad40c | 2004-08-12 19:06:24 +0000 | [diff] [blame] | 351 | |
Gabor Greif | 04367bf | 2007-07-06 22:07:22 +0000 | [diff] [blame] | 352 | <li><tt>llvm/lib/BitCode/Reader/Reader.cpp</tt>: |
| 353 | modify <tt>const Type *BitcodeReader::ParseType()</tt> to read your data |
Misha Brukman | 7cc8a89 | 2004-08-12 19:58:43 +0000 | [diff] [blame] | 354 | type</li> |
Chris Lattner | 8dad40c | 2004-08-12 19:06:24 +0000 | [diff] [blame] | 355 | |
| 356 | <li><tt>llvm/lib/VMCore/AsmWriter.cpp</tt>: |
Misha Brukman | 7cc8a89 | 2004-08-12 19:58:43 +0000 | [diff] [blame] | 357 | modify |
| 358 | <div class="doc_code"> |
| 359 | <pre> |
| 360 | void calcTypeName(const Type *Ty, |
| 361 | std::vector<const Type*> &TypeStack, |
| 362 | std::map<const Type*,std::string> &TypeNames, |
| 363 | std::string & Result) |
| 364 | </pre> |
| 365 | </div> |
Chris Lattner | 8dad40c | 2004-08-12 19:06:24 +0000 | [diff] [blame] | 366 | to output the new derived type |
| 367 | </li> |
| 368 | |
| 369 | |
| 370 | </ol> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 371 | |
| 372 | </div> |
| 373 | |
NAKAMURA Takumi | f5af6ad | 2011-04-23 00:30:22 +0000 | [diff] [blame] | 374 | </div> |
| 375 | |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 376 | <!-- *********************************************************************** --> |
| 377 | |
| 378 | <hr> |
| 379 | <address> |
| 380 | <a href="http://jigsaw.w3.org/css-validator/check/referer"><img |
Misha Brukman | 4440870 | 2008-12-11 17:34:48 +0000 | [diff] [blame] | 381 | src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 382 | <a href="http://validator.w3.org/check/referer"><img |
Misha Brukman | f00ddb0 | 2008-12-11 18:23:24 +0000 | [diff] [blame] | 383 | src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 384 | |
NAKAMURA Takumi | b9a3363 | 2011-04-09 02:13:37 +0000 | [diff] [blame] | 385 | <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a> |
Misha Brukman | a3ce429 | 2004-04-06 03:53:49 +0000 | [diff] [blame] | 386 | <br> |
| 387 | Last modified: $Date$ |
| 388 | </address> |
| 389 | |
| 390 | </body> |
| 391 | </html> |