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Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]6 <title>Kaleidoscope: Extending the Language: User-defined Operators</title>
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8 <meta name="author" content="Chris Lattner">
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11
12<body>
13
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]14<div class="doc_title">Kaleidoscope: Extending the Language: User-defined Operators</div>
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]15
Chris Lattner128eb862007-11-05 19:06:59 +0000[diff] [blame]16<ul>
Chris Lattner0e555b12007-11-05 20:04:56 +0000[diff] [blame]17<li><a href="index.html">Up to Tutorial Index</a></li>
Chris Lattner128eb862007-11-05 19:06:59 +0000[diff] [blame]18<li>Chapter 6
19 <ol>
20 <li><a href="#intro">Chapter 6 Introduction</a></li>
21 <li><a href="#idea">User-defined Operators: the Idea</a></li>
22 <li><a href="#binary">User-defined Binary Operators</a></li>
23 <li><a href="#unary">User-defined Unary Operators</a></li>
24 <li><a href="#example">Kicking the Tires</a></li>
25 <li><a href="#code">Full Code Listing</a></li>
26 </ol>
27</li>
Chris Lattner0e555b12007-11-05 20:04:56 +0000[diff] [blame]28<li><a href="LangImpl7.html">Chapter 7</a>: Extending the Language: Mutable
29Variables / SSA Construction</li>
Chris Lattner128eb862007-11-05 19:06:59 +0000[diff] [blame]30</ul>
31
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]32<div class="doc_author">
33 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></p>
34</div>
35
36<!-- *********************************************************************** -->
Chris Lattner128eb862007-11-05 19:06:59 +0000[diff] [blame]37<div class="doc_section"><a name="intro">Chapter 6 Introduction</a></div>
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]38<!-- *********************************************************************** -->
39
40<div class="doc_text">
41
Chris Lattner128eb862007-11-05 19:06:59 +0000[diff] [blame]42<p>Welcome to Chapter 6 of the "<a href="index.html">Implementing a language
43with LLVM</a>" tutorial. At this point in our tutorial, we now have a fully
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]44functional language that is fairly minimal, but also useful. There
45is still one big problem with it, however. Our language doesn't have many
46useful operators (like division, logical negation, or even any comparisons
47besides less-than).</p>
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]48
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]49<p>This chapter of the tutorial takes a wild digression into adding user-defined
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]50operators to the simple and beautiful Kaleidoscope language. This digression now gives
51us a simple and ugly language in some ways, but also a powerful one at the same time.
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]52One of the great things about creating your own language is that you get to
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]53decide what is good or bad. In this tutorial we'll assume that it is okay to
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]54use this as a way to show some interesting parsing techniques.</p>
55
Chris Lattner3616a8a2007-11-07 06:06:38 +0000[diff] [blame]56<p>At the end of this tutorial, we'll run through an example Kaleidoscope
57application that <a href="#example">renders the Mandelbrot set</a>. This gives
58an example of what you can build with Kaleidoscope and its feature set.</p>
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]59
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]60</div>
61
62<!-- *********************************************************************** -->
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]63<div class="doc_section"><a name="idea">User-defined Operators: the Idea</a></div>
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]64<!-- *********************************************************************** -->
65
66<div class="doc_text">
67
68<p>
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]69The "operator overloading" that we will add to Kaleidoscope is more general than
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]70languages like C++. In C++, you are only allowed to redefine existing
71operators: you can't programatically change the grammar, introduce new
72operators, change precedence levels, etc. In this chapter, we will add this
Chris Lattner3616a8a2007-11-07 06:06:38 +0000[diff] [blame]73capability to Kaleidoscope, which will let the user round out the set of
74operators that are supported.</p>
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]75
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]76<p>The point of going into user-defined operators in a tutorial like this is to
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]77show the power and flexibility of using a hand-written parser. Thus far, the parser
78we have been implementing uses recursive descent for most parts of the grammar and
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]79operator precedence parsing for the expressions. See <a
80href="LangImpl2.html">Chapter 2</a> for details. Without using operator
81precedence parsing, it would be very difficult to allow the programmer to
82introduce new operators into the grammar: the grammar is dynamically extensible
83as the JIT runs.</p>
84
85<p>The two specific features we'll add are programmable unary operators (right
86now, Kaleidoscope has no unary operators at all) as well as binary operators.
87An example of this is:</p>
88
89<div class="doc_code">
90<pre>
91# Logical unary not.
92def unary!(v)
93 if v then
94 0
95 else
96 1;
97
98# Define &gt; with the same precedence as &lt;.
99def binary&gt; 10 (LHS RHS)
Chris Lattner61ad4492007-11-23 22:19:33 +0000[diff] [blame]100 RHS &lt; LHS;
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]101
102# Binary "logical or", (note that it does not "short circuit")
103def binary| 5 (LHS RHS)
104 if LHS then
105 1
106 else if RHS then
107 1
108 else
109 0;
110
111# Define = with slightly lower precedence than relationals.
112def binary= 9 (LHS RHS)
113 !(LHS &lt; RHS | LHS &gt; RHS);
114</pre>
115</div>
116
117<p>Many languages aspire to being able to implement their standard runtime
118library in the language itself. In Kaleidoscope, we can implement significant
119parts of the language in the library!</p>
120
121<p>We will break down implementation of these features into two parts:
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]122implementing support for user-defined binary operators and adding unary
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]123operators.</p>
124
125</div>
126
127<!-- *********************************************************************** -->
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]128<div class="doc_section"><a name="binary">User-defined Binary Operators</a></div>
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]129<!-- *********************************************************************** -->
130
131<div class="doc_text">
132
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]133<p>Adding support for user-defined binary operators is pretty simple with our
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]134current framework. We'll first add support for the unary/binary keywords:</p>
135
136<div class="doc_code">
137<pre>
138enum Token {
139 ...
140 <b>// operators
141 tok_binary = -11, tok_unary = -12</b>
142};
143...
144static int gettok() {
145...
146 if (IdentifierStr == "for") return tok_for;
147 if (IdentifierStr == "in") return tok_in;
148 <b>if (IdentifierStr == "binary") return tok_binary;
149 if (IdentifierStr == "unary") return tok_unary;</b>
150 return tok_identifier;
151</pre>
152</div>
153
154<p>This just adds lexer support for the unary and binary keywords, like we
155did in <a href="LangImpl5.html#iflexer">previous chapters</a>. One nice thing
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]156about our current AST, is that we represent binary operators with full generalisation
157by using their ASCII code as the opcode. For our extended operators, we'll use this
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]158same representation, so we don't need any new AST or parser support.</p>
159
160<p>On the other hand, we have to be able to represent the definitions of these
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]161new operators, in the "def binary| 5" part of the function definition. In our
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]162grammar so far, the "name" for the function definition is parsed as the
163"prototype" production and into the <tt>PrototypeAST</tt> AST node. To
164represent our new user-defined operators as prototypes, we have to extend
165the <tt>PrototypeAST</tt> AST node like this:</p>
166
167<div class="doc_code">
168<pre>
169/// PrototypeAST - This class represents the "prototype" for a function,
170/// which captures its argument names as well as if it is an operator.
171class PrototypeAST {
172 std::string Name;
173 std::vector&lt;std::string&gt; Args;
174 <b>bool isOperator;
175 unsigned Precedence; // Precedence if a binary op.</b>
176public:
177 PrototypeAST(const std::string &amp;name, const std::vector&lt;std::string&gt; &amp;args,
178 <b>bool isoperator = false, unsigned prec = 0</b>)
179 : Name(name), Args(args), <b>isOperator(isoperator), Precedence(prec)</b> {}
180
181 <b>bool isUnaryOp() const { return isOperator &amp;&amp; Args.size() == 1; }
182 bool isBinaryOp() const { return isOperator &amp;&amp; Args.size() == 2; }
183
184 char getOperatorName() const {
185 assert(isUnaryOp() || isBinaryOp());
186 return Name[Name.size()-1];
187 }
188
189 unsigned getBinaryPrecedence() const { return Precedence; }</b>
190
191 Function *Codegen();
192};
193</pre>
194</div>
195
196<p>Basically, in addition to knowing a name for the prototype, we now keep track
197of whether it was an operator, and if it was, what precedence level the operator
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]198is at. The precedence is only used for binary operators (as you'll see below,
199it just doesn't apply for unary operators). Now that we have a way to represent
200the prototype for a user-defined operator, we need to parse it:</p>
201
202<div class="doc_code">
203<pre>
204/// prototype
205/// ::= id '(' id* ')'
206<b>/// ::= binary LETTER number? (id, id)</b>
207static PrototypeAST *ParsePrototype() {
208 std::string FnName;
209
Nick Lewycky422094c2009-09-13 21:38:54 +0000[diff] [blame]210 <b>unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]211 unsigned BinaryPrecedence = 30;</b>
212
213 switch (CurTok) {
214 default:
215 return ErrorP("Expected function name in prototype");
216 case tok_identifier:
217 FnName = IdentifierStr;
218 Kind = 0;
219 getNextToken();
220 break;
221 <b>case tok_binary:
222 getNextToken();
223 if (!isascii(CurTok))
224 return ErrorP("Expected binary operator");
225 FnName = "binary";
226 FnName += (char)CurTok;
227 Kind = 2;
228 getNextToken();
229
230 // Read the precedence if present.
231 if (CurTok == tok_number) {
232 if (NumVal &lt; 1 || NumVal &gt; 100)
233 return ErrorP("Invalid precedecnce: must be 1..100");
234 BinaryPrecedence = (unsigned)NumVal;
235 getNextToken();
236 }
237 break;</b>
238 }
239
240 if (CurTok != '(')
241 return ErrorP("Expected '(' in prototype");
242
243 std::vector&lt;std::string&gt; ArgNames;
244 while (getNextToken() == tok_identifier)
245 ArgNames.push_back(IdentifierStr);
246 if (CurTok != ')')
247 return ErrorP("Expected ')' in prototype");
248
249 // success.
250 getNextToken(); // eat ')'.
251
252 <b>// Verify right number of names for operator.
253 if (Kind &amp;&amp; ArgNames.size() != Kind)
254 return ErrorP("Invalid number of operands for operator");
255
256 return new PrototypeAST(FnName, ArgNames, Kind != 0, BinaryPrecedence);</b>
257}
258</pre>
259</div>
260
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]261<p>This is all fairly straightforward parsing code, and we have already seen
262a lot of similar code in the past. One interesting part about the code above is
263the couple lines that set up <tt>FnName</tt> for binary operators. This builds names
264like "binary@" for a newly defined "@" operator. This then takes advantage of the
265fact that symbol names in the LLVM symbol table are allowed to have any character in
266them, including embedded nul characters.</p>
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]267
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]268<p>The next interesting thing to add, is codegen support for these binary operators.
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]269Given our current structure, this is a simple addition of a default case for our
270existing binary operator node:</p>
271
272<div class="doc_code">
273<pre>
274Value *BinaryExprAST::Codegen() {
275 Value *L = LHS-&gt;Codegen();
276 Value *R = RHS-&gt;Codegen();
277 if (L == 0 || R == 0) return 0;
278
279 switch (Op) {
280 case '+': return Builder.CreateAdd(L, R, "addtmp");
281 case '-': return Builder.CreateSub(L, R, "subtmp");
282 case '*': return Builder.CreateMul(L, R, "multmp");
283 case '&lt;':
Chris Lattner71155212007-11-06 01:39:12 +0000[diff] [blame]284 L = Builder.CreateFCmpULT(L, R, "cmptmp");
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]285 // Convert bool 0/1 to double 0.0 or 1.0
Nick Lewycky422094c2009-09-13 21:38:54 +0000[diff] [blame]286 return Builder.CreateUIToFP(L, Type::getDoubleTy(getGlobalContext()),
287 "booltmp");
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]288 <b>default: break;</b>
289 }
290
291 <b>// If it wasn't a builtin binary operator, it must be a user defined one. Emit
292 // a call to it.
293 Function *F = TheModule-&gt;getFunction(std::string("binary")+Op);
294 assert(F &amp;&amp; "binary operator not found!");
295
296 Value *Ops[] = { L, R };
297 return Builder.CreateCall(F, Ops, Ops+2, "binop");</b>
298}
299
300</pre>
301</div>
302
303<p>As you can see above, the new code is actually really simple. It just does
304a lookup for the appropriate operator in the symbol table and generates a
305function call to it. Since user-defined operators are just built as normal
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]306functions (because the "prototype" boils down to a function with the right
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]307name) everything falls into place.</p>
308
Erick Tryzelaarfd1ec5e2009-09-22 21:14:49 +0000[diff] [blame]309<p>The final piece of code we are missing, is a bit of top-level magic:</p>
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]310
311<div class="doc_code">
312<pre>
313Function *FunctionAST::Codegen() {
314 NamedValues.clear();
315
316 Function *TheFunction = Proto->Codegen();
317 if (TheFunction == 0)
318 return 0;
319
320 <b>// If this is an operator, install it.
321 if (Proto-&gt;isBinaryOp())
322 BinopPrecedence[Proto->getOperatorName()] = Proto->getBinaryPrecedence();</b>
323
324 // Create a new basic block to start insertion into.
Owen Anderson1d0be152009-08-13 21:58:54 +0000[diff] [blame]325 BasicBlock *BB = BasicBlock::Create(getGlobalContext(), "entry", TheFunction);
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]326 Builder.SetInsertPoint(BB);
327
328 if (Value *RetVal = Body-&gt;Codegen()) {
329 ...
330</pre>
331</div>
332
333<p>Basically, before codegening a function, if it is a user-defined operator, we
334register it in the precedence table. This allows the binary operator parsing
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]335logic we already have in place to handle it. Since we are working on a fully-general operator precedence parser, this is all we need to do to "extend the grammar".</p>
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]336
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]337<p>Now we have useful user-defined binary operators. This builds a lot
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]338on the previous framework we built for other operators. Adding unary operators
Chris Lattner3616a8a2007-11-07 06:06:38 +0000[diff] [blame]339is a bit more challenging, because we don't have any framework for it yet - lets
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]340see what it takes.</p>
341
342</div>
343
344<!-- *********************************************************************** -->
345<div class="doc_section"><a name="unary">User-defined Unary Operators</a></div>
346<!-- *********************************************************************** -->
347
348<div class="doc_text">
349
350<p>Since we don't currently support unary operators in the Kaleidoscope
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]351language, we'll need to add everything to support them. Above, we added simple
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]352support for the 'unary' keyword to the lexer. In addition to that, we need an
353AST node:</p>
354
355<div class="doc_code">
356<pre>
357/// UnaryExprAST - Expression class for a unary operator.
358class UnaryExprAST : public ExprAST {
359 char Opcode;
360 ExprAST *Operand;
361public:
362 UnaryExprAST(char opcode, ExprAST *operand)
363 : Opcode(opcode), Operand(operand) {}
364 virtual Value *Codegen();
365};
366</pre>
367</div>
368
369<p>This AST node is very simple and obvious by now. It directly mirrors the
370binary operator AST node, except that it only has one child. With this, we
371need to add the parsing logic. Parsing a unary operator is pretty simple: we'll
372add a new function to do it:</p>
373
374<div class="doc_code">
375<pre>
376/// unary
377/// ::= primary
378/// ::= '!' unary
379static ExprAST *ParseUnary() {
380 // If the current token is not an operator, it must be a primary expr.
381 if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')
382 return ParsePrimary();
383
384 // If this is a unary operator, read it.
385 int Opc = CurTok;
386 getNextToken();
387 if (ExprAST *Operand = ParseUnary())
388 return new UnaryExprAST(Opc, Operand);
389 return 0;
390}
391</pre>
392</div>
393
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]394<p>The grammar we add is pretty straightforward here. If we see a unary
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]395operator when parsing a primary operator, we eat the operator as a prefix and
396parse the remaining piece as another unary operator. This allows us to handle
397multiple unary operators (e.g. "!!x"). Note that unary operators can't have
398ambiguous parses like binary operators can, so there is no need for precedence
399information.</p>
400
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]401<p>The problem with this function, is that we need to call ParseUnary from somewhere.
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]402To do this, we change previous callers of ParsePrimary to call ParseUnary
403instead:</p>
404
405<div class="doc_code">
406<pre>
407/// binoprhs
408/// ::= ('+' unary)*
409static ExprAST *ParseBinOpRHS(int ExprPrec, ExprAST *LHS) {
410 ...
411 <b>// Parse the unary expression after the binary operator.
412 ExprAST *RHS = ParseUnary();
413 if (!RHS) return 0;</b>
414 ...
415}
416/// expression
417/// ::= unary binoprhs
418///
419static ExprAST *ParseExpression() {
420 <b>ExprAST *LHS = ParseUnary();</b>
421 if (!LHS) return 0;
422
423 return ParseBinOpRHS(0, LHS);
424}
425</pre>
426</div>
427
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]428<p>With these two simple changes, we are now able to parse unary operators and build the
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]429AST for them. Next up, we need to add parser support for prototypes, to parse
430the unary operator prototype. We extend the binary operator code above
431with:</p>
432
433<div class="doc_code">
434<pre>
435/// prototype
436/// ::= id '(' id* ')'
437/// ::= binary LETTER number? (id, id)
438<b>/// ::= unary LETTER (id)</b>
439static PrototypeAST *ParsePrototype() {
440 std::string FnName;
441
Nick Lewycky422094c2009-09-13 21:38:54 +0000[diff] [blame]442 unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]443 unsigned BinaryPrecedence = 30;
444
445 switch (CurTok) {
446 default:
447 return ErrorP("Expected function name in prototype");
448 case tok_identifier:
449 FnName = IdentifierStr;
450 Kind = 0;
451 getNextToken();
452 break;
453 <b>case tok_unary:
454 getNextToken();
455 if (!isascii(CurTok))
456 return ErrorP("Expected unary operator");
457 FnName = "unary";
458 FnName += (char)CurTok;
459 Kind = 1;
460 getNextToken();
461 break;</b>
462 case tok_binary:
463 ...
464</pre>
465</div>
466
467<p>As with binary operators, we name unary operators with a name that includes
468the operator character. This assists us at code generation time. Speaking of,
469the final piece we need to add is codegen support for unary operators. It looks
470like this:</p>
471
472<div class="doc_code">
473<pre>
474Value *UnaryExprAST::Codegen() {
475 Value *OperandV = Operand->Codegen();
476 if (OperandV == 0) return 0;
477
478 Function *F = TheModule->getFunction(std::string("unary")+Opcode);
479 if (F == 0)
480 return ErrorV("Unknown unary operator");
481
482 return Builder.CreateCall(F, OperandV, "unop");
483}
484</pre>
485</div>
486
487<p>This code is similar to, but simpler than, the code for binary operators. It
488is simpler primarily because it doesn't need to handle any predefined operators.
489</p>
490
491</div>
492
493<!-- *********************************************************************** -->
494<div class="doc_section"><a name="example">Kicking the Tires</a></div>
495<!-- *********************************************************************** -->
496
497<div class="doc_text">
498
499<p>It is somewhat hard to believe, but with a few simple extensions we've
Chris Lattnerb5d81b32007-11-02 05:54:25 +0000[diff] [blame]500covered in the last chapters, we have grown a real-ish language. With this, we
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]501can do a lot of interesting things, including I/O, math, and a bunch of other
502things. For example, we can now add a nice sequencing operator (printd is
503defined to print out the specified value and a newline):</p>
504
505<div class="doc_code">
506<pre>
507ready&gt; <b>extern printd(x);</b>
508Read extern: declare double @printd(double)
509ready&gt; <b>def binary : 1 (x y) 0; # Low-precedence operator that ignores operands.</b>
510..
511ready&gt; <b>printd(123) : printd(456) : printd(789);</b>
512123.000000
513456.000000
514789.000000
515Evaluated to 0.000000
516</pre>
517</div>
518
Chris Lattnerb5d81b32007-11-02 05:54:25 +0000[diff] [blame]519<p>We can also define a bunch of other "primitive" operations, such as:</p>
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]520
521<div class="doc_code">
522<pre>
523# Logical unary not.
524def unary!(v)
525 if v then
526 0
527 else
528 1;
529
530# Unary negate.
531def unary-(v)
532 0-v;
533
Chris Lattner3616a8a2007-11-07 06:06:38 +0000[diff] [blame]534# Define &gt; with the same precedence as &gt;.
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]535def binary&gt; 10 (LHS RHS)
Chris Lattner61ad4492007-11-23 22:19:33 +0000[diff] [blame]536 RHS &lt; LHS;
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]537
538# Binary logical or, which does not short circuit.
539def binary| 5 (LHS RHS)
540 if LHS then
541 1
542 else if RHS then
543 1
544 else
545 0;
546
547# Binary logical and, which does not short circuit.
548def binary&amp; 6 (LHS RHS)
549 if !LHS then
550 0
551 else
552 !!RHS;
553
554# Define = with slightly lower precedence than relationals.
555def binary = 9 (LHS RHS)
556 !(LHS &lt; RHS | LHS &gt; RHS);
557
558</pre>
559</div>
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]560
561
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]562<p>Given the previous if/then/else support, we can also define interesting
563functions for I/O. For example, the following prints out a character whose
564"density" reflects the value passed in: the lower the value, the denser the
565character:</p>
566
567<div class="doc_code">
568<pre>
569ready&gt;
570<b>
571extern putchard(char)
572def printdensity(d)
573 if d &gt; 8 then
574 putchard(32) # ' '
575 else if d &gt; 4 then
576 putchard(46) # '.'
577 else if d &gt; 2 then
578 putchard(43) # '+'
579 else
580 putchard(42); # '*'</b>
581...
582ready&gt; <b>printdensity(1): printdensity(2): printdensity(3) :
583 printdensity(4): printdensity(5): printdensity(9): putchard(10);</b>
584*++..
585Evaluated to 0.000000
586</pre>
587</div>
588
589<p>Based on these simple primitive operations, we can start to define more
590interesting things. For example, here's a little function that solves for the
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]591number of iterations it takes a function in the complex plane to
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]592converge:</p>
593
594<div class="doc_code">
595<pre>
596# determine whether the specific location diverges.
597# Solve for z = z^2 + c in the complex plane.
598def mandleconverger(real imag iters creal cimag)
599 if iters &gt; 255 | (real*real + imag*imag &gt; 4) then
600 iters
601 else
602 mandleconverger(real*real - imag*imag + creal,
603 2*real*imag + cimag,
604 iters+1, creal, cimag);
605
606# return the number of iterations required for the iteration to escape
607def mandleconverge(real imag)
608 mandleconverger(real, imag, 0, real, imag);
609</pre>
610</div>
611
Chris Lattnerb5d81b32007-11-02 05:54:25 +0000[diff] [blame]612<p>This "z = z<sup>2</sup> + c" function is a beautiful little creature that is the basis
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]613for computation of the <a
614href="http://en.wikipedia.org/wiki/Mandelbrot_set">Mandelbrot Set</a>. Our
615<tt>mandelconverge</tt> function returns the number of iterations that it takes
616for a complex orbit to escape, saturating to 255. This is not a very useful
617function by itself, but if you plot its value over a two-dimensional plane,
Chris Lattner3616a8a2007-11-07 06:06:38 +0000[diff] [blame]618you can see the Mandelbrot set. Given that we are limited to using putchard
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]619here, our amazing graphical output is limited, but we can whip together
620something using the density plotter above:</p>
621
622<div class="doc_code">
623<pre>
Chris Lattner3616a8a2007-11-07 06:06:38 +0000[diff] [blame]624# compute and plot the mandlebrot set with the specified 2 dimensional range
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]625# info.
626def mandelhelp(xmin xmax xstep ymin ymax ystep)
627 for y = ymin, y &lt; ymax, ystep in (
628 (for x = xmin, x &lt; xmax, xstep in
629 printdensity(mandleconverge(x,y)))
630 : putchard(10)
631 )
632
633# mandel - This is a convenient helper function for ploting the mandelbrot set
Chris Lattner3616a8a2007-11-07 06:06:38 +0000[diff] [blame]634# from the specified position with the specified Magnification.
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]635def mandel(realstart imagstart realmag imagmag)
636 mandelhelp(realstart, realstart+realmag*78, realmag,
637 imagstart, imagstart+imagmag*40, imagmag);
638</pre>
639</div>
640
641<p>Given this, we can try plotting out the mandlebrot set! Lets try it out:</p>
642
643<div class="doc_code">
644<pre>
645ready&gt; <b>mandel(-2.3, -1.3, 0.05, 0.07);</b>
646*******************************+++++++++++*************************************
647*************************+++++++++++++++++++++++*******************************
648**********************+++++++++++++++++++++++++++++****************************
649*******************+++++++++++++++++++++.. ...++++++++*************************
650*****************++++++++++++++++++++++.... ...+++++++++***********************
651***************+++++++++++++++++++++++..... ...+++++++++*********************
652**************+++++++++++++++++++++++.... ....+++++++++********************
653*************++++++++++++++++++++++...... .....++++++++*******************
654************+++++++++++++++++++++....... .......+++++++******************
655***********+++++++++++++++++++.... ... .+++++++*****************
656**********+++++++++++++++++....... .+++++++****************
657*********++++++++++++++........... ...+++++++***************
658********++++++++++++............ ...++++++++**************
659********++++++++++... .......... .++++++++**************
660*******+++++++++..... .+++++++++*************
661*******++++++++...... ..+++++++++*************
662*******++++++....... ..+++++++++*************
663*******+++++...... ..+++++++++*************
664*******.... .... ...+++++++++*************
665*******.... . ...+++++++++*************
666*******+++++...... ...+++++++++*************
667*******++++++....... ..+++++++++*************
668*******++++++++...... .+++++++++*************
669*******+++++++++..... ..+++++++++*************
670********++++++++++... .......... .++++++++**************
671********++++++++++++............ ...++++++++**************
672*********++++++++++++++.......... ...+++++++***************
673**********++++++++++++++++........ .+++++++****************
674**********++++++++++++++++++++.... ... ..+++++++****************
675***********++++++++++++++++++++++....... .......++++++++*****************
676************+++++++++++++++++++++++...... ......++++++++******************
677**************+++++++++++++++++++++++.... ....++++++++********************
678***************+++++++++++++++++++++++..... ...+++++++++*********************
679*****************++++++++++++++++++++++.... ...++++++++***********************
680*******************+++++++++++++++++++++......++++++++*************************
681*********************++++++++++++++++++++++.++++++++***************************
682*************************+++++++++++++++++++++++*******************************
683******************************+++++++++++++************************************
684*******************************************************************************
685*******************************************************************************
686*******************************************************************************
687Evaluated to 0.000000
688ready&gt; <b>mandel(-2, -1, 0.02, 0.04);</b>
689**************************+++++++++++++++++++++++++++++++++++++++++++++++++++++
690***********************++++++++++++++++++++++++++++++++++++++++++++++++++++++++
691*********************+++++++++++++++++++++++++++++++++++++++++++++++++++++++++.
692*******************+++++++++++++++++++++++++++++++++++++++++++++++++++++++++...
693*****************+++++++++++++++++++++++++++++++++++++++++++++++++++++++++.....
694***************++++++++++++++++++++++++++++++++++++++++++++++++++++++++........
695**************++++++++++++++++++++++++++++++++++++++++++++++++++++++...........
696************+++++++++++++++++++++++++++++++++++++++++++++++++++++..............
697***********++++++++++++++++++++++++++++++++++++++++++++++++++........ .
698**********++++++++++++++++++++++++++++++++++++++++++++++.............
699********+++++++++++++++++++++++++++++++++++++++++++..................
700*******+++++++++++++++++++++++++++++++++++++++.......................
701******+++++++++++++++++++++++++++++++++++...........................
702*****++++++++++++++++++++++++++++++++............................
703*****++++++++++++++++++++++++++++...............................
704****++++++++++++++++++++++++++...... .........................
705***++++++++++++++++++++++++......... ...... ...........
706***++++++++++++++++++++++............
707**+++++++++++++++++++++..............
708**+++++++++++++++++++................
709*++++++++++++++++++.................
710*++++++++++++++++............ ...
711*++++++++++++++..............
712*+++....++++................
713*.......... ...........
714*
715*.......... ...........
716*+++....++++................
717*++++++++++++++..............
718*++++++++++++++++............ ...
719*++++++++++++++++++.................
720**+++++++++++++++++++................
721**+++++++++++++++++++++..............
722***++++++++++++++++++++++............
723***++++++++++++++++++++++++......... ...... ...........
724****++++++++++++++++++++++++++...... .........................
725*****++++++++++++++++++++++++++++...............................
726*****++++++++++++++++++++++++++++++++............................
727******+++++++++++++++++++++++++++++++++++...........................
728*******+++++++++++++++++++++++++++++++++++++++.......................
729********+++++++++++++++++++++++++++++++++++++++++++..................
730Evaluated to 0.000000
731ready&gt; <b>mandel(-0.9, -1.4, 0.02, 0.03);</b>
732*******************************************************************************
733*******************************************************************************
734*******************************************************************************
735**********+++++++++++++++++++++************************************************
736*+++++++++++++++++++++++++++++++++++++++***************************************
737+++++++++++++++++++++++++++++++++++++++++++++**********************************
738++++++++++++++++++++++++++++++++++++++++++++++++++*****************************
739++++++++++++++++++++++++++++++++++++++++++++++++++++++*************************
740+++++++++++++++++++++++++++++++++++++++++++++++++++++++++**********************
741+++++++++++++++++++++++++++++++++.........++++++++++++++++++*******************
742+++++++++++++++++++++++++++++++.... ......+++++++++++++++++++****************
743+++++++++++++++++++++++++++++....... ........+++++++++++++++++++**************
744++++++++++++++++++++++++++++........ ........++++++++++++++++++++************
745+++++++++++++++++++++++++++......... .. ...+++++++++++++++++++++**********
746++++++++++++++++++++++++++........... ....++++++++++++++++++++++********
747++++++++++++++++++++++++............. .......++++++++++++++++++++++******
748+++++++++++++++++++++++............. ........+++++++++++++++++++++++****
749++++++++++++++++++++++........... ..........++++++++++++++++++++++***
750++++++++++++++++++++........... .........++++++++++++++++++++++*
751++++++++++++++++++............ ...........++++++++++++++++++++
752++++++++++++++++............... .............++++++++++++++++++
753++++++++++++++................. ...............++++++++++++++++
754++++++++++++.................. .................++++++++++++++
755+++++++++.................. .................+++++++++++++
756++++++........ . ......... ..++++++++++++
757++............ ...... ....++++++++++
758.............. ...++++++++++
759.............. ....+++++++++
760.............. .....++++++++
761............. ......++++++++
762........... .......++++++++
763......... ........+++++++
764......... ........+++++++
765......... ....+++++++
766........ ...+++++++
767....... ...+++++++
768 ....+++++++
769 .....+++++++
770 ....+++++++
771 ....+++++++
772 ....+++++++
773Evaluated to 0.000000
774ready&gt; <b>^D</b>
775</pre>
776</div>
777
778<p>At this point, you may be starting to realize that Kaleidoscope is a real
779and powerful language. It may not be self-similar :), but it can be used to
780plot things that are!</p>
781
782<p>With this, we conclude the "adding user-defined operators" chapter of the
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]783tutorial. We have successfully augmented our language, adding the ability to extend the
784language in the library, and we have shown how this can be used to build a simple but
Chris Lattner3616a8a2007-11-07 06:06:38 +0000[diff] [blame]785interesting end-user application in Kaleidoscope. At this point, Kaleidoscope
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]786can build a variety of applications that are functional and can call functions
Chris Lattnerb5d81b32007-11-02 05:54:25 +0000[diff] [blame]787with side-effects, but it can't actually define and mutate a variable itself.
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]788</p>
789
Chris Lattner3616a8a2007-11-07 06:06:38 +0000[diff] [blame]790<p>Strikingly, variable mutation is an important feature of some
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]791languages, and it is not at all obvious how to <a href="LangImpl7.html">add
792support for mutable variables</a> without having to add an "SSA construction"
793phase to your front-end. In the next chapter, we will describe how you can
Chris Lattnerb7e6b1a2007-11-15 04:51:31 +0000[diff] [blame]794add variable mutation without building SSA in your front-end.</p>
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]795
796</div>
797
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]798<!-- *********************************************************************** -->
799<div class="doc_section"><a name="code">Full Code Listing</a></div>
800<!-- *********************************************************************** -->
801
802<div class="doc_text">
803
804<p>
805Here is the complete code listing for our running example, enhanced with the
806if/then/else and for expressions.. To build this example, use:
807</p>
808
809<div class="doc_code">
810<pre>
811 # Compile
812 g++ -g toy.cpp `llvm-config --cppflags --ldflags --libs core jit native` -O3 -o toy
813 # Run
814 ./toy
815</pre>
816</div>
817
818<p>Here is the code:</p>
819
820<div class="doc_code">
821<pre>
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]822#include "llvm/DerivedTypes.h"
823#include "llvm/ExecutionEngine/ExecutionEngine.h"
Nick Lewycky422094c2009-09-13 21:38:54 +0000[diff] [blame]824#include "llvm/ExecutionEngine/Interpreter.h"
825#include "llvm/ExecutionEngine/JIT.h"
Owen Andersond1fbd142009-07-08 20:50:47 +0000[diff] [blame]826#include "llvm/LLVMContext.h"
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]827#include "llvm/Module.h"
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]828#include "llvm/PassManager.h"
829#include "llvm/Analysis/Verifier.h"
830#include "llvm/Target/TargetData.h"
Nick Lewycky422094c2009-09-13 21:38:54 +0000[diff] [blame]831#include "llvm/Target/TargetSelect.h"
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]832#include "llvm/Transforms/Scalar.h"
Duncan Sands89f6d882008-04-13 06:22:09 +0000[diff] [blame]833#include "llvm/Support/IRBuilder.h"
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]834#include &lt;cstdio&gt;
835#include &lt;string&gt;
836#include &lt;map&gt;
837#include &lt;vector&gt;
838using namespace llvm;
839
840//===----------------------------------------------------------------------===//
841// Lexer
842//===----------------------------------------------------------------------===//
843
844// The lexer returns tokens [0-255] if it is an unknown character, otherwise one
845// of these for known things.
846enum Token {
847 tok_eof = -1,
848
849 // commands
850 tok_def = -2, tok_extern = -3,
851
852 // primary
853 tok_identifier = -4, tok_number = -5,
854
855 // control
856 tok_if = -6, tok_then = -7, tok_else = -8,
857 tok_for = -9, tok_in = -10,
858
859 // operators
860 tok_binary = -11, tok_unary = -12
861};
862
863static std::string IdentifierStr; // Filled in if tok_identifier
864static double NumVal; // Filled in if tok_number
865
866/// gettok - Return the next token from standard input.
867static int gettok() {
868 static int LastChar = ' ';
869
870 // Skip any whitespace.
871 while (isspace(LastChar))
872 LastChar = getchar();
873
874 if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
875 IdentifierStr = LastChar;
876 while (isalnum((LastChar = getchar())))
877 IdentifierStr += LastChar;
878
879 if (IdentifierStr == "def") return tok_def;
880 if (IdentifierStr == "extern") return tok_extern;
881 if (IdentifierStr == "if") return tok_if;
882 if (IdentifierStr == "then") return tok_then;
883 if (IdentifierStr == "else") return tok_else;
884 if (IdentifierStr == "for") return tok_for;
885 if (IdentifierStr == "in") return tok_in;
886 if (IdentifierStr == "binary") return tok_binary;
887 if (IdentifierStr == "unary") return tok_unary;
888 return tok_identifier;
889 }
890
891 if (isdigit(LastChar) || LastChar == '.') { // Number: [0-9.]+
892 std::string NumStr;
893 do {
894 NumStr += LastChar;
895 LastChar = getchar();
896 } while (isdigit(LastChar) || LastChar == '.');
897
898 NumVal = strtod(NumStr.c_str(), 0);
899 return tok_number;
900 }
901
902 if (LastChar == '#') {
903 // Comment until end of line.
904 do LastChar = getchar();
Chris Lattnerc80c23f2007-12-02 22:46:01 +0000[diff] [blame]905 while (LastChar != EOF &amp;&amp; LastChar != '\n' &amp;&amp; LastChar != '\r');
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]906
907 if (LastChar != EOF)
908 return gettok();
909 }
910
911 // Check for end of file. Don't eat the EOF.
912 if (LastChar == EOF)
913 return tok_eof;
914
915 // Otherwise, just return the character as its ascii value.
916 int ThisChar = LastChar;
917 LastChar = getchar();
918 return ThisChar;
919}
920
921//===----------------------------------------------------------------------===//
922// Abstract Syntax Tree (aka Parse Tree)
923//===----------------------------------------------------------------------===//
924
925/// ExprAST - Base class for all expression nodes.
926class ExprAST {
927public:
928 virtual ~ExprAST() {}
929 virtual Value *Codegen() = 0;
930};
931
932/// NumberExprAST - Expression class for numeric literals like "1.0".
933class NumberExprAST : public ExprAST {
934 double Val;
935public:
936 NumberExprAST(double val) : Val(val) {}
937 virtual Value *Codegen();
938};
939
940/// VariableExprAST - Expression class for referencing a variable, like "a".
941class VariableExprAST : public ExprAST {
942 std::string Name;
943public:
944 VariableExprAST(const std::string &amp;name) : Name(name) {}
945 virtual Value *Codegen();
946};
947
948/// UnaryExprAST - Expression class for a unary operator.
949class UnaryExprAST : public ExprAST {
950 char Opcode;
951 ExprAST *Operand;
952public:
953 UnaryExprAST(char opcode, ExprAST *operand)
954 : Opcode(opcode), Operand(operand) {}
955 virtual Value *Codegen();
956};
957
958/// BinaryExprAST - Expression class for a binary operator.
959class BinaryExprAST : public ExprAST {
960 char Op;
961 ExprAST *LHS, *RHS;
962public:
963 BinaryExprAST(char op, ExprAST *lhs, ExprAST *rhs)
964 : Op(op), LHS(lhs), RHS(rhs) {}
965 virtual Value *Codegen();
966};
967
968/// CallExprAST - Expression class for function calls.
969class CallExprAST : public ExprAST {
970 std::string Callee;
971 std::vector&lt;ExprAST*&gt; Args;
972public:
973 CallExprAST(const std::string &amp;callee, std::vector&lt;ExprAST*&gt; &amp;args)
974 : Callee(callee), Args(args) {}
975 virtual Value *Codegen();
976};
977
978/// IfExprAST - Expression class for if/then/else.
979class IfExprAST : public ExprAST {
980 ExprAST *Cond, *Then, *Else;
981public:
982 IfExprAST(ExprAST *cond, ExprAST *then, ExprAST *_else)
983 : Cond(cond), Then(then), Else(_else) {}
984 virtual Value *Codegen();
985};
986
987/// ForExprAST - Expression class for for/in.
988class ForExprAST : public ExprAST {
989 std::string VarName;
990 ExprAST *Start, *End, *Step, *Body;
991public:
992 ForExprAST(const std::string &amp;varname, ExprAST *start, ExprAST *end,
993 ExprAST *step, ExprAST *body)
994 : VarName(varname), Start(start), End(end), Step(step), Body(body) {}
995 virtual Value *Codegen();
996};
997
998/// PrototypeAST - This class represents the "prototype" for a function,
Erick Tryzelaarfd1ec5e2009-09-22 21:14:49 +0000[diff] [blame]999/// which captures its name, and its argument names (thus implicitly the number
1000/// of arguments the function takes), as well as if it is an operator.
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1001class PrototypeAST {
1002 std::string Name;
1003 std::vector&lt;std::string&gt; Args;
1004 bool isOperator;
1005 unsigned Precedence; // Precedence if a binary op.
1006public:
1007 PrototypeAST(const std::string &amp;name, const std::vector&lt;std::string&gt; &amp;args,
1008 bool isoperator = false, unsigned prec = 0)
1009 : Name(name), Args(args), isOperator(isoperator), Precedence(prec) {}
1010
1011 bool isUnaryOp() const { return isOperator &amp;&amp; Args.size() == 1; }
1012 bool isBinaryOp() const { return isOperator &amp;&amp; Args.size() == 2; }
1013
1014 char getOperatorName() const {
1015 assert(isUnaryOp() || isBinaryOp());
1016 return Name[Name.size()-1];
1017 }
1018
1019 unsigned getBinaryPrecedence() const { return Precedence; }
1020
1021 Function *Codegen();
1022};
1023
1024/// FunctionAST - This class represents a function definition itself.
1025class FunctionAST {
1026 PrototypeAST *Proto;
1027 ExprAST *Body;
1028public:
1029 FunctionAST(PrototypeAST *proto, ExprAST *body)
1030 : Proto(proto), Body(body) {}
1031
1032 Function *Codegen();
1033};
1034
1035//===----------------------------------------------------------------------===//
1036// Parser
1037//===----------------------------------------------------------------------===//
1038
1039/// CurTok/getNextToken - Provide a simple token buffer. CurTok is the current
Erick Tryzelaarfd1ec5e2009-09-22 21:14:49 +0000[diff] [blame]1040/// token the parser is looking at. getNextToken reads another token from the
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1041/// lexer and updates CurTok with its results.
1042static int CurTok;
1043static int getNextToken() {
1044 return CurTok = gettok();
1045}
1046
1047/// BinopPrecedence - This holds the precedence for each binary operator that is
1048/// defined.
1049static std::map&lt;char, int&gt; BinopPrecedence;
1050
1051/// GetTokPrecedence - Get the precedence of the pending binary operator token.
1052static int GetTokPrecedence() {
1053 if (!isascii(CurTok))
1054 return -1;
1055
1056 // Make sure it's a declared binop.
1057 int TokPrec = BinopPrecedence[CurTok];
1058 if (TokPrec &lt;= 0) return -1;
1059 return TokPrec;
1060}
1061
1062/// Error* - These are little helper functions for error handling.
1063ExprAST *Error(const char *Str) { fprintf(stderr, "Error: %s\n", Str);return 0;}
1064PrototypeAST *ErrorP(const char *Str) { Error(Str); return 0; }
1065FunctionAST *ErrorF(const char *Str) { Error(Str); return 0; }
1066
1067static ExprAST *ParseExpression();
1068
1069/// identifierexpr
Chris Lattner20a0c802007-11-05 17:54:34 +0000[diff] [blame]1070/// ::= identifier
1071/// ::= identifier '(' expression* ')'
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1072static ExprAST *ParseIdentifierExpr() {
1073 std::string IdName = IdentifierStr;
1074
Chris Lattner20a0c802007-11-05 17:54:34 +0000[diff] [blame]1075 getNextToken(); // eat identifier.
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1076
1077 if (CurTok != '(') // Simple variable ref.
1078 return new VariableExprAST(IdName);
1079
1080 // Call.
1081 getNextToken(); // eat (
1082 std::vector&lt;ExprAST*&gt; Args;
1083 if (CurTok != ')') {
1084 while (1) {
1085 ExprAST *Arg = ParseExpression();
1086 if (!Arg) return 0;
1087 Args.push_back(Arg);
Erick Tryzelaarfd1ec5e2009-09-22 21:14:49 +0000[diff] [blame]1088
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1089 if (CurTok == ')') break;
Erick Tryzelaarfd1ec5e2009-09-22 21:14:49 +0000[diff] [blame]1090
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1091 if (CurTok != ',')
Chris Lattner6c4be9c2008-04-14 16:44:41 +0000[diff] [blame]1092 return Error("Expected ')' or ',' in argument list");
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1093 getNextToken();
1094 }
1095 }
1096
1097 // Eat the ')'.
1098 getNextToken();
1099
1100 return new CallExprAST(IdName, Args);
1101}
1102
1103/// numberexpr ::= number
1104static ExprAST *ParseNumberExpr() {
1105 ExprAST *Result = new NumberExprAST(NumVal);
1106 getNextToken(); // consume the number
1107 return Result;
1108}
1109
1110/// parenexpr ::= '(' expression ')'
1111static ExprAST *ParseParenExpr() {
1112 getNextToken(); // eat (.
1113 ExprAST *V = ParseExpression();
1114 if (!V) return 0;
1115
1116 if (CurTok != ')')
1117 return Error("expected ')'");
1118 getNextToken(); // eat ).
1119 return V;
1120}
1121
1122/// ifexpr ::= 'if' expression 'then' expression 'else' expression
1123static ExprAST *ParseIfExpr() {
1124 getNextToken(); // eat the if.
1125
1126 // condition.
1127 ExprAST *Cond = ParseExpression();
1128 if (!Cond) return 0;
1129
1130 if (CurTok != tok_then)
1131 return Error("expected then");
1132 getNextToken(); // eat the then
1133
1134 ExprAST *Then = ParseExpression();
1135 if (Then == 0) return 0;
1136
1137 if (CurTok != tok_else)
1138 return Error("expected else");
1139
1140 getNextToken();
1141
1142 ExprAST *Else = ParseExpression();
1143 if (!Else) return 0;
1144
1145 return new IfExprAST(Cond, Then, Else);
1146}
1147
Chris Lattner20a0c802007-11-05 17:54:34 +0000[diff] [blame]1148/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1149static ExprAST *ParseForExpr() {
1150 getNextToken(); // eat the for.
1151
1152 if (CurTok != tok_identifier)
1153 return Error("expected identifier after for");
1154
1155 std::string IdName = IdentifierStr;
Chris Lattner20a0c802007-11-05 17:54:34 +0000[diff] [blame]1156 getNextToken(); // eat identifier.
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1157
1158 if (CurTok != '=')
1159 return Error("expected '=' after for");
1160 getNextToken(); // eat '='.
1161
1162
1163 ExprAST *Start = ParseExpression();
1164 if (Start == 0) return 0;
1165 if (CurTok != ',')
1166 return Error("expected ',' after for start value");
1167 getNextToken();
1168
1169 ExprAST *End = ParseExpression();
1170 if (End == 0) return 0;
1171
1172 // The step value is optional.
1173 ExprAST *Step = 0;
1174 if (CurTok == ',') {
1175 getNextToken();
1176 Step = ParseExpression();
1177 if (Step == 0) return 0;
1178 }
1179
1180 if (CurTok != tok_in)
1181 return Error("expected 'in' after for");
1182 getNextToken(); // eat 'in'.
1183
1184 ExprAST *Body = ParseExpression();
1185 if (Body == 0) return 0;
1186
1187 return new ForExprAST(IdName, Start, End, Step, Body);
1188}
1189
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1190/// primary
1191/// ::= identifierexpr
1192/// ::= numberexpr
1193/// ::= parenexpr
1194/// ::= ifexpr
1195/// ::= forexpr
1196static ExprAST *ParsePrimary() {
1197 switch (CurTok) {
1198 default: return Error("unknown token when expecting an expression");
1199 case tok_identifier: return ParseIdentifierExpr();
1200 case tok_number: return ParseNumberExpr();
1201 case '(': return ParseParenExpr();
1202 case tok_if: return ParseIfExpr();
1203 case tok_for: return ParseForExpr();
1204 }
1205}
1206
1207/// unary
1208/// ::= primary
1209/// ::= '!' unary
1210static ExprAST *ParseUnary() {
1211 // If the current token is not an operator, it must be a primary expr.
1212 if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')
1213 return ParsePrimary();
1214
1215 // If this is a unary operator, read it.
1216 int Opc = CurTok;
1217 getNextToken();
1218 if (ExprAST *Operand = ParseUnary())
1219 return new UnaryExprAST(Opc, Operand);
1220 return 0;
1221}
1222
1223/// binoprhs
1224/// ::= ('+' unary)*
1225static ExprAST *ParseBinOpRHS(int ExprPrec, ExprAST *LHS) {
1226 // If this is a binop, find its precedence.
1227 while (1) {
1228 int TokPrec = GetTokPrecedence();
1229
1230 // If this is a binop that binds at least as tightly as the current binop,
1231 // consume it, otherwise we are done.
1232 if (TokPrec &lt; ExprPrec)
1233 return LHS;
1234
1235 // Okay, we know this is a binop.
1236 int BinOp = CurTok;
1237 getNextToken(); // eat binop
1238
1239 // Parse the unary expression after the binary operator.
1240 ExprAST *RHS = ParseUnary();
1241 if (!RHS) return 0;
1242
1243 // If BinOp binds less tightly with RHS than the operator after RHS, let
1244 // the pending operator take RHS as its LHS.
1245 int NextPrec = GetTokPrecedence();
1246 if (TokPrec &lt; NextPrec) {
1247 RHS = ParseBinOpRHS(TokPrec+1, RHS);
1248 if (RHS == 0) return 0;
1249 }
1250
1251 // Merge LHS/RHS.
1252 LHS = new BinaryExprAST(BinOp, LHS, RHS);
1253 }
1254}
1255
1256/// expression
1257/// ::= unary binoprhs
1258///
1259static ExprAST *ParseExpression() {
1260 ExprAST *LHS = ParseUnary();
1261 if (!LHS) return 0;
1262
1263 return ParseBinOpRHS(0, LHS);
1264}
1265
1266/// prototype
1267/// ::= id '(' id* ')'
1268/// ::= binary LETTER number? (id, id)
1269/// ::= unary LETTER (id)
1270static PrototypeAST *ParsePrototype() {
1271 std::string FnName;
1272
Erick Tryzelaarfd1ec5e2009-09-22 21:14:49 +0000[diff] [blame]1273 unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1274 unsigned BinaryPrecedence = 30;
1275
1276 switch (CurTok) {
1277 default:
1278 return ErrorP("Expected function name in prototype");
1279 case tok_identifier:
1280 FnName = IdentifierStr;
1281 Kind = 0;
1282 getNextToken();
1283 break;
1284 case tok_unary:
1285 getNextToken();
1286 if (!isascii(CurTok))
1287 return ErrorP("Expected unary operator");
1288 FnName = "unary";
1289 FnName += (char)CurTok;
1290 Kind = 1;
1291 getNextToken();
1292 break;
1293 case tok_binary:
1294 getNextToken();
1295 if (!isascii(CurTok))
1296 return ErrorP("Expected binary operator");
1297 FnName = "binary";
1298 FnName += (char)CurTok;
1299 Kind = 2;
1300 getNextToken();
1301
1302 // Read the precedence if present.
1303 if (CurTok == tok_number) {
1304 if (NumVal &lt; 1 || NumVal &gt; 100)
1305 return ErrorP("Invalid precedecnce: must be 1..100");
1306 BinaryPrecedence = (unsigned)NumVal;
1307 getNextToken();
1308 }
1309 break;
1310 }
1311
1312 if (CurTok != '(')
1313 return ErrorP("Expected '(' in prototype");
1314
1315 std::vector&lt;std::string&gt; ArgNames;
1316 while (getNextToken() == tok_identifier)
1317 ArgNames.push_back(IdentifierStr);
1318 if (CurTok != ')')
1319 return ErrorP("Expected ')' in prototype");
1320
1321 // success.
1322 getNextToken(); // eat ')'.
1323
1324 // Verify right number of names for operator.
1325 if (Kind &amp;&amp; ArgNames.size() != Kind)
1326 return ErrorP("Invalid number of operands for operator");
1327
1328 return new PrototypeAST(FnName, ArgNames, Kind != 0, BinaryPrecedence);
1329}
1330
1331/// definition ::= 'def' prototype expression
1332static FunctionAST *ParseDefinition() {
1333 getNextToken(); // eat def.
1334 PrototypeAST *Proto = ParsePrototype();
1335 if (Proto == 0) return 0;
1336
1337 if (ExprAST *E = ParseExpression())
1338 return new FunctionAST(Proto, E);
1339 return 0;
1340}
1341
1342/// toplevelexpr ::= expression
1343static FunctionAST *ParseTopLevelExpr() {
1344 if (ExprAST *E = ParseExpression()) {
1345 // Make an anonymous proto.
1346 PrototypeAST *Proto = new PrototypeAST("", std::vector&lt;std::string&gt;());
1347 return new FunctionAST(Proto, E);
1348 }
1349 return 0;
1350}
1351
1352/// external ::= 'extern' prototype
1353static PrototypeAST *ParseExtern() {
1354 getNextToken(); // eat extern.
1355 return ParsePrototype();
1356}
1357
1358//===----------------------------------------------------------------------===//
1359// Code Generation
1360//===----------------------------------------------------------------------===//
1361
1362static Module *TheModule;
Owen Andersond1fbd142009-07-08 20:50:47 +0000[diff] [blame]1363static IRBuilder&lt;&gt; Builder(getGlobalContext());
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1364static std::map&lt;std::string, Value*&gt; NamedValues;
1365static FunctionPassManager *TheFPM;
1366
1367Value *ErrorV(const char *Str) { Error(Str); return 0; }
1368
1369Value *NumberExprAST::Codegen() {
Owen Anderson6f83c9c2009-07-27 20:59:43 +0000[diff] [blame]1370 return ConstantFP::get(getGlobalContext(), APFloat(Val));
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1371}
1372
1373Value *VariableExprAST::Codegen() {
1374 // Look this variable up in the function.
1375 Value *V = NamedValues[Name];
1376 return V ? V : ErrorV("Unknown variable name");
1377}
1378
1379Value *UnaryExprAST::Codegen() {
1380 Value *OperandV = Operand-&gt;Codegen();
1381 if (OperandV == 0) return 0;
1382
1383 Function *F = TheModule-&gt;getFunction(std::string("unary")+Opcode);
1384 if (F == 0)
1385 return ErrorV("Unknown unary operator");
1386
1387 return Builder.CreateCall(F, OperandV, "unop");
1388}
1389
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1390Value *BinaryExprAST::Codegen() {
1391 Value *L = LHS-&gt;Codegen();
1392 Value *R = RHS-&gt;Codegen();
1393 if (L == 0 || R == 0) return 0;
1394
1395 switch (Op) {
1396 case '+': return Builder.CreateAdd(L, R, "addtmp");
1397 case '-': return Builder.CreateSub(L, R, "subtmp");
1398 case '*': return Builder.CreateMul(L, R, "multmp");
1399 case '&lt;':
Chris Lattner71155212007-11-06 01:39:12 +0000[diff] [blame]1400 L = Builder.CreateFCmpULT(L, R, "cmptmp");
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1401 // Convert bool 0/1 to double 0.0 or 1.0
Erick Tryzelaarfd1ec5e2009-09-22 21:14:49 +0000[diff] [blame]1402 return Builder.CreateUIToFP(L, Type::getDoubleTy(getGlobalContext()),
1403 "booltmp");
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1404 default: break;
1405 }
1406
1407 // If it wasn't a builtin binary operator, it must be a user defined one. Emit
1408 // a call to it.
1409 Function *F = TheModule-&gt;getFunction(std::string("binary")+Op);
1410 assert(F &amp;&amp; "binary operator not found!");
1411
1412 Value *Ops[] = { L, R };
1413 return Builder.CreateCall(F, Ops, Ops+2, "binop");
1414}
1415
1416Value *CallExprAST::Codegen() {
1417 // Look up the name in the global module table.
1418 Function *CalleeF = TheModule-&gt;getFunction(Callee);
1419 if (CalleeF == 0)
1420 return ErrorV("Unknown function referenced");
1421
1422 // If argument mismatch error.
1423 if (CalleeF-&gt;arg_size() != Args.size())
1424 return ErrorV("Incorrect # arguments passed");
1425
1426 std::vector&lt;Value*&gt; ArgsV;
1427 for (unsigned i = 0, e = Args.size(); i != e; ++i) {
1428 ArgsV.push_back(Args[i]-&gt;Codegen());
1429 if (ArgsV.back() == 0) return 0;
1430 }
1431
1432 return Builder.CreateCall(CalleeF, ArgsV.begin(), ArgsV.end(), "calltmp");
1433}
1434
1435Value *IfExprAST::Codegen() {
1436 Value *CondV = Cond-&gt;Codegen();
1437 if (CondV == 0) return 0;
1438
1439 // Convert condition to a bool by comparing equal to 0.0.
1440 CondV = Builder.CreateFCmpONE(CondV,
Owen Anderson6f83c9c2009-07-27 20:59:43 +0000[diff] [blame]1441 ConstantFP::get(getGlobalContext(), APFloat(0.0)),
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1442 "ifcond");
1443
1444 Function *TheFunction = Builder.GetInsertBlock()-&gt;getParent();
1445
1446 // Create blocks for the then and else cases. Insert the 'then' block at the
1447 // end of the function.
Owen Anderson1d0be152009-08-13 21:58:54 +0000[diff] [blame]1448 BasicBlock *ThenBB = BasicBlock::Create(getGlobalContext(), "then", TheFunction);
1449 BasicBlock *ElseBB = BasicBlock::Create(getGlobalContext(), "else");
1450 BasicBlock *MergeBB = BasicBlock::Create(getGlobalContext(), "ifcont");
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1451
1452 Builder.CreateCondBr(CondV, ThenBB, ElseBB);
1453
1454 // Emit then value.
1455 Builder.SetInsertPoint(ThenBB);
1456
1457 Value *ThenV = Then-&gt;Codegen();
1458 if (ThenV == 0) return 0;
1459
1460 Builder.CreateBr(MergeBB);
1461 // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
1462 ThenBB = Builder.GetInsertBlock();
1463
1464 // Emit else block.
1465 TheFunction-&gt;getBasicBlockList().push_back(ElseBB);
1466 Builder.SetInsertPoint(ElseBB);
1467
1468 Value *ElseV = Else-&gt;Codegen();
1469 if (ElseV == 0) return 0;
1470
1471 Builder.CreateBr(MergeBB);
1472 // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
1473 ElseBB = Builder.GetInsertBlock();
1474
1475 // Emit merge block.
1476 TheFunction-&gt;getBasicBlockList().push_back(MergeBB);
1477 Builder.SetInsertPoint(MergeBB);
Nick Lewycky422094c2009-09-13 21:38:54 +0000[diff] [blame]1478 PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()),
1479 "iftmp");
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1480
1481 PN-&gt;addIncoming(ThenV, ThenBB);
1482 PN-&gt;addIncoming(ElseV, ElseBB);
1483 return PN;
1484}
1485
1486Value *ForExprAST::Codegen() {
1487 // Output this as:
1488 // ...
1489 // start = startexpr
1490 // goto loop
1491 // loop:
1492 // variable = phi [start, loopheader], [nextvariable, loopend]
1493 // ...
1494 // bodyexpr
1495 // ...
1496 // loopend:
1497 // step = stepexpr
1498 // nextvariable = variable + step
1499 // endcond = endexpr
1500 // br endcond, loop, endloop
1501 // outloop:
1502
1503 // Emit the start code first, without 'variable' in scope.
1504 Value *StartVal = Start-&gt;Codegen();
1505 if (StartVal == 0) return 0;
1506
1507 // Make the new basic block for the loop header, inserting after current
1508 // block.
1509 Function *TheFunction = Builder.GetInsertBlock()-&gt;getParent();
1510 BasicBlock *PreheaderBB = Builder.GetInsertBlock();
Owen Anderson1d0be152009-08-13 21:58:54 +0000[diff] [blame]1511 BasicBlock *LoopBB = BasicBlock::Create(getGlobalContext(), "loop", TheFunction);
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1512
1513 // Insert an explicit fall through from the current block to the LoopBB.
1514 Builder.CreateBr(LoopBB);
1515
1516 // Start insertion in LoopBB.
1517 Builder.SetInsertPoint(LoopBB);
1518
1519 // Start the PHI node with an entry for Start.
Owen Anderson1d0be152009-08-13 21:58:54 +0000[diff] [blame]1520 PHINode *Variable = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()), VarName.c_str());
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1521 Variable-&gt;addIncoming(StartVal, PreheaderBB);
1522
1523 // Within the loop, the variable is defined equal to the PHI node. If it
1524 // shadows an existing variable, we have to restore it, so save it now.
1525 Value *OldVal = NamedValues[VarName];
1526 NamedValues[VarName] = Variable;
1527
1528 // Emit the body of the loop. This, like any other expr, can change the
1529 // current BB. Note that we ignore the value computed by the body, but don't
1530 // allow an error.
1531 if (Body-&gt;Codegen() == 0)
1532 return 0;
1533
1534 // Emit the step value.
1535 Value *StepVal;
1536 if (Step) {
1537 StepVal = Step-&gt;Codegen();
1538 if (StepVal == 0) return 0;
1539 } else {
1540 // If not specified, use 1.0.
Owen Anderson6f83c9c2009-07-27 20:59:43 +0000[diff] [blame]1541 StepVal = ConstantFP::get(getGlobalContext(), APFloat(1.0));
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1542 }
1543
1544 Value *NextVar = Builder.CreateAdd(Variable, StepVal, "nextvar");
1545
1546 // Compute the end condition.
1547 Value *EndCond = End-&gt;Codegen();
1548 if (EndCond == 0) return EndCond;
1549
1550 // Convert condition to a bool by comparing equal to 0.0.
1551 EndCond = Builder.CreateFCmpONE(EndCond,
Owen Anderson6f83c9c2009-07-27 20:59:43 +0000[diff] [blame]1552 ConstantFP::get(getGlobalContext(), APFloat(0.0)),
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1553 "loopcond");
1554
1555 // Create the "after loop" block and insert it.
1556 BasicBlock *LoopEndBB = Builder.GetInsertBlock();
Owen Anderson1d0be152009-08-13 21:58:54 +0000[diff] [blame]1557 BasicBlock *AfterBB = BasicBlock::Create(getGlobalContext(), "afterloop", TheFunction);
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1558
1559 // Insert the conditional branch into the end of LoopEndBB.
1560 Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
1561
1562 // Any new code will be inserted in AfterBB.
1563 Builder.SetInsertPoint(AfterBB);
1564
1565 // Add a new entry to the PHI node for the backedge.
1566 Variable-&gt;addIncoming(NextVar, LoopEndBB);
1567
1568 // Restore the unshadowed variable.
1569 if (OldVal)
1570 NamedValues[VarName] = OldVal;
1571 else
1572 NamedValues.erase(VarName);
1573
1574
1575 // for expr always returns 0.0.
Owen Anderson1d0be152009-08-13 21:58:54 +0000[diff] [blame]1576 return Constant::getNullValue(Type::getDoubleTy(getGlobalContext()));
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1577}
1578
1579Function *PrototypeAST::Codegen() {
1580 // Make the function type: double(double,double) etc.
Nick Lewycky422094c2009-09-13 21:38:54 +0000[diff] [blame]1581 std::vector&lt;const Type*&gt; Doubles(Args.size(),
1582 Type::getDoubleTy(getGlobalContext()));
1583 FunctionType *FT = FunctionType::get(Type::getDoubleTy(getGlobalContext()),
1584 Doubles, false);
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1585
Gabor Greifdf7d2b42008-04-19 22:25:09 +0000[diff] [blame]1586 Function *F = Function::Create(FT, Function::ExternalLinkage, Name, TheModule);
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1587
1588 // If F conflicted, there was already something named 'Name'. If it has a
1589 // body, don't allow redefinition or reextern.
1590 if (F-&gt;getName() != Name) {
1591 // Delete the one we just made and get the existing one.
1592 F-&gt;eraseFromParent();
1593 F = TheModule-&gt;getFunction(Name);
1594
1595 // If F already has a body, reject this.
1596 if (!F-&gt;empty()) {
1597 ErrorF("redefinition of function");
1598 return 0;
1599 }
1600
1601 // If F took a different number of args, reject.
1602 if (F-&gt;arg_size() != Args.size()) {
1603 ErrorF("redefinition of function with different # args");
1604 return 0;
1605 }
1606 }
1607
1608 // Set names for all arguments.
1609 unsigned Idx = 0;
1610 for (Function::arg_iterator AI = F-&gt;arg_begin(); Idx != Args.size();
1611 ++AI, ++Idx) {
1612 AI-&gt;setName(Args[Idx]);
1613
1614 // Add arguments to variable symbol table.
1615 NamedValues[Args[Idx]] = AI;
1616 }
1617
1618 return F;
1619}
1620
1621Function *FunctionAST::Codegen() {
1622 NamedValues.clear();
1623
1624 Function *TheFunction = Proto-&gt;Codegen();
1625 if (TheFunction == 0)
1626 return 0;
1627
1628 // If this is an operator, install it.
1629 if (Proto-&gt;isBinaryOp())
1630 BinopPrecedence[Proto-&gt;getOperatorName()] = Proto-&gt;getBinaryPrecedence();
1631
1632 // Create a new basic block to start insertion into.
Owen Anderson1d0be152009-08-13 21:58:54 +0000[diff] [blame]1633 BasicBlock *BB = BasicBlock::Create(getGlobalContext(), "entry", TheFunction);
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1634 Builder.SetInsertPoint(BB);
1635
1636 if (Value *RetVal = Body-&gt;Codegen()) {
1637 // Finish off the function.
1638 Builder.CreateRet(RetVal);
1639
1640 // Validate the generated code, checking for consistency.
1641 verifyFunction(*TheFunction);
1642
1643 // Optimize the function.
1644 TheFPM-&gt;run(*TheFunction);
1645
1646 return TheFunction;
1647 }
1648
1649 // Error reading body, remove function.
1650 TheFunction-&gt;eraseFromParent();
1651
1652 if (Proto-&gt;isBinaryOp())
1653 BinopPrecedence.erase(Proto-&gt;getOperatorName());
1654 return 0;
1655}
1656
1657//===----------------------------------------------------------------------===//
1658// Top-Level parsing and JIT Driver
1659//===----------------------------------------------------------------------===//
1660
1661static ExecutionEngine *TheExecutionEngine;
1662
1663static void HandleDefinition() {
1664 if (FunctionAST *F = ParseDefinition()) {
1665 if (Function *LF = F-&gt;Codegen()) {
1666 fprintf(stderr, "Read function definition:");
1667 LF-&gt;dump();
1668 }
1669 } else {
1670 // Skip token for error recovery.
1671 getNextToken();
1672 }
1673}
1674
1675static void HandleExtern() {
1676 if (PrototypeAST *P = ParseExtern()) {
1677 if (Function *F = P-&gt;Codegen()) {
1678 fprintf(stderr, "Read extern: ");
1679 F-&gt;dump();
1680 }
1681 } else {
1682 // Skip token for error recovery.
1683 getNextToken();
1684 }
1685}
1686
1687static void HandleTopLevelExpression() {
Erick Tryzelaarfd1ec5e2009-09-22 21:14:49 +0000[diff] [blame]1688 // Evaluate a top-level expression into an anonymous function.
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1689 if (FunctionAST *F = ParseTopLevelExpr()) {
1690 if (Function *LF = F-&gt;Codegen()) {
1691 // JIT the function, returning a function pointer.
1692 void *FPtr = TheExecutionEngine-&gt;getPointerToFunction(LF);
1693
1694 // Cast it to the right type (takes no arguments, returns a double) so we
1695 // can call it as a native function.
Nick Lewycky422094c2009-09-13 21:38:54 +0000[diff] [blame]1696 double (*FP)() = (double (*)())(intptr_t)FPtr;
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1697 fprintf(stderr, "Evaluated to %f\n", FP());
1698 }
1699 } else {
1700 // Skip token for error recovery.
1701 getNextToken();
1702 }
1703}
1704
1705/// top ::= definition | external | expression | ';'
1706static void MainLoop() {
1707 while (1) {
1708 fprintf(stderr, "ready&gt; ");
1709 switch (CurTok) {
1710 case tok_eof: return;
Erick Tryzelaarfd1ec5e2009-09-22 21:14:49 +0000[diff] [blame]1711 case ';': getNextToken(); break; // ignore top-level semicolons.
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1712 case tok_def: HandleDefinition(); break;
1713 case tok_extern: HandleExtern(); break;
1714 default: HandleTopLevelExpression(); break;
1715 }
1716 }
1717}
1718
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1719//===----------------------------------------------------------------------===//
1720// "Library" functions that can be "extern'd" from user code.
1721//===----------------------------------------------------------------------===//
1722
1723/// putchard - putchar that takes a double and returns 0.
1724extern "C"
1725double putchard(double X) {
1726 putchar((char)X);
1727 return 0;
1728}
1729
1730/// printd - printf that takes a double prints it as "%f\n", returning 0.
1731extern "C"
1732double printd(double X) {
1733 printf("%f\n", X);
1734 return 0;
1735}
1736
1737//===----------------------------------------------------------------------===//
1738// Main driver code.
1739//===----------------------------------------------------------------------===//
1740
1741int main() {
Erick Tryzelaarfd1ec5e2009-09-22 21:14:49 +0000[diff] [blame]1742 InitializeNativeTarget();
1743 LLVMContext &amp;Context = getGlobalContext();
1744
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1745 // Install standard binary operators.
1746 // 1 is lowest precedence.
1747 BinopPrecedence['&lt;'] = 10;
1748 BinopPrecedence['+'] = 20;
1749 BinopPrecedence['-'] = 20;
1750 BinopPrecedence['*'] = 40; // highest.
1751
1752 // Prime the first token.
1753 fprintf(stderr, "ready&gt; ");
1754 getNextToken();
1755
1756 // Make the module, which holds all the code.
Erick Tryzelaarfd1ec5e2009-09-22 21:14:49 +0000[diff] [blame]1757 TheModule = new Module("my cool jit", Context);
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1758
Jeffrey Yasskinf0356fe2010-01-27 20:34:15 +0000[diff] [blame]1759 // Create the JIT. This takes ownership of the module.
1760 TheExecutionEngine = EngineBuilder(TheModule).create();
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1761
Jeffrey Yasskinf0356fe2010-01-27 20:34:15 +0000[diff] [blame]1762 FunctionPassManager OurFPM(TheModule);
Reid Kleckner60130f02009-08-26 20:58:25 +0000[diff] [blame]1763
1764 // Set up the optimizer pipeline. Start with registering info about how the
1765 // target lays out data structures.
1766 OurFPM.add(new TargetData(*TheExecutionEngine-&gt;getTargetData()));
1767 // Do simple "peephole" optimizations and bit-twiddling optzns.
1768 OurFPM.add(createInstructionCombiningPass());
1769 // Reassociate expressions.
1770 OurFPM.add(createReassociatePass());
1771 // Eliminate Common SubExpressions.
1772 OurFPM.add(createGVNPass());
1773 // Simplify the control flow graph (deleting unreachable blocks, etc).
1774 OurFPM.add(createCFGSimplificationPass());
1775
Nick Lewycky422094c2009-09-13 21:38:54 +0000[diff] [blame]1776 OurFPM.doInitialization();
1777
Reid Kleckner60130f02009-08-26 20:58:25 +0000[diff] [blame]1778 // Set the global so the code gen can use this.
1779 TheFPM = &amp;OurFPM;
1780
1781 // Run the main "interpreter loop" now.
1782 MainLoop();
1783
1784 TheFPM = 0;
1785
1786 // Print out all of the generated code.
1787 TheModule-&gt;dump();
1788
Chris Lattner58f2c872007-11-02 05:42:52 +0000[diff] [blame]1789 return 0;
1790}
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]1791</pre>
1792</div>
1793
Chris Lattner729eb142008-02-10 19:11:04 +0000[diff] [blame]1794<a href="LangImpl7.html">Next: Extending the language: mutable variables / SSA construction</a>
Chris Lattnerc9d5d2c2007-11-01 06:49:54 +0000[diff] [blame]1795</div>
1796
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Dan Gohman523e3922010-02-03 17:27:31 +0000[diff] [blame]1807 Last modified: $Date$
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