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diff --git a/docs/tutorial/LangImpl6.html b/docs/tutorial/LangImpl6.html deleted file mode 100644 index bf502e7da9..0000000000 --- a/docs/tutorial/LangImpl6.html +++ /dev/null @@ -1,1829 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" - "http://www.w3.org/TR/html4/strict.dtd"> - -<html> -<head> - <title>Kaleidoscope: Extending the Language: User-defined Operators</title> - <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> - <meta name="author" content="Chris Lattner"> - <link rel="stylesheet" href="../_static/llvm.css" type="text/css"> -</head> - -<body> - -<h1>Kaleidoscope: Extending the Language: User-defined Operators</h1> - -<ul> -<li><a href="index.html">Up to Tutorial Index</a></li> -<li>Chapter 6 - <ol> - <li><a href="#intro">Chapter 6 Introduction</a></li> - <li><a href="#idea">User-defined Operators: the Idea</a></li> - <li><a href="#binary">User-defined Binary Operators</a></li> - <li><a href="#unary">User-defined Unary Operators</a></li> - <li><a href="#example">Kicking the Tires</a></li> - <li><a href="#code">Full Code Listing</a></li> - </ol> -</li> -<li><a href="LangImpl7.html">Chapter 7</a>: Extending the Language: Mutable -Variables / SSA Construction</li> -</ul> - -<div class="doc_author"> - <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></p> -</div> - -<!-- *********************************************************************** --> -<h2><a name="intro">Chapter 6 Introduction</a></h2> -<!-- *********************************************************************** --> - -<div> - -<p>Welcome to Chapter 6 of the "<a href="index.html">Implementing a language -with LLVM</a>" tutorial. At this point in our tutorial, we now have a fully -functional language that is fairly minimal, but also useful. There -is still one big problem with it, however. Our language doesn't have many -useful operators (like division, logical negation, or even any comparisons -besides less-than).</p> - -<p>This chapter of the tutorial takes a wild digression into adding user-defined -operators to the simple and beautiful Kaleidoscope language. This digression now gives -us a simple and ugly language in some ways, but also a powerful one at the same time. -One of the great things about creating your own language is that you get to -decide what is good or bad. In this tutorial we'll assume that it is okay to -use this as a way to show some interesting parsing techniques.</p> - -<p>At the end of this tutorial, we'll run through an example Kaleidoscope -application that <a href="#example">renders the Mandelbrot set</a>. This gives -an example of what you can build with Kaleidoscope and its feature set.</p> - -</div> - -<!-- *********************************************************************** --> -<h2><a name="idea">User-defined Operators: the Idea</a></h2> -<!-- *********************************************************************** --> - -<div> - -<p> -The "operator overloading" that we will add to Kaleidoscope is more general than -languages like C++. In C++, you are only allowed to redefine existing -operators: you can't programatically change the grammar, introduce new -operators, change precedence levels, etc. In this chapter, we will add this -capability to Kaleidoscope, which will let the user round out the set of -operators that are supported.</p> - -<p>The point of going into user-defined operators in a tutorial like this is to -show the power and flexibility of using a hand-written parser. Thus far, the parser -we have been implementing uses recursive descent for most parts of the grammar and -operator precedence parsing for the expressions. See <a -href="LangImpl2.html">Chapter 2</a> for details. Without using operator -precedence parsing, it would be very difficult to allow the programmer to -introduce new operators into the grammar: the grammar is dynamically extensible -as the JIT runs.</p> - -<p>The two specific features we'll add are programmable unary operators (right -now, Kaleidoscope has no unary operators at all) as well as binary operators. -An example of this is:</p> - -<div class="doc_code"> -<pre> -# Logical unary not. -def unary!(v) - if v then - 0 - else - 1; - -# Define > with the same precedence as <. -def binary> 10 (LHS RHS) - RHS < LHS; - -# Binary "logical or", (note that it does not "short circuit") -def binary| 5 (LHS RHS) - if LHS then - 1 - else if RHS then - 1 - else - 0; - -# Define = with slightly lower precedence than relationals. -def binary= 9 (LHS RHS) - !(LHS < RHS | LHS > RHS); -</pre> -</div> - -<p>Many languages aspire to being able to implement their standard runtime -library in the language itself. In Kaleidoscope, we can implement significant -parts of the language in the library!</p> - -<p>We will break down implementation of these features into two parts: -implementing support for user-defined binary operators and adding unary -operators.</p> - -</div> - -<!-- *********************************************************************** --> -<h2><a name="binary">User-defined Binary Operators</a></h2> -<!-- *********************************************************************** --> - -<div> - -<p>Adding support for user-defined binary operators is pretty simple with our -current framework. We'll first add support for the unary/binary keywords:</p> - -<div class="doc_code"> -<pre> -enum Token { - ... - <b>// operators - tok_binary = -11, tok_unary = -12</b> -}; -... -static int gettok() { -... - if (IdentifierStr == "for") return tok_for; - if (IdentifierStr == "in") return tok_in; - <b>if (IdentifierStr == "binary") return tok_binary; - if (IdentifierStr == "unary") return tok_unary;</b> - return tok_identifier; -</pre> -</div> - -<p>This just adds lexer support for the unary and binary keywords, like we -did in <a href="LangImpl5.html#iflexer">previous chapters</a>. One nice thing -about our current AST, is that we represent binary operators with full generalisation -by using their ASCII code as the opcode. For our extended operators, we'll use this -same representation, so we don't need any new AST or parser support.</p> - -<p>On the other hand, we have to be able to represent the definitions of these -new operators, in the "def binary| 5" part of the function definition. In our -grammar so far, the "name" for the function definition is parsed as the -"prototype" production and into the <tt>PrototypeAST</tt> AST node. To -represent our new user-defined operators as prototypes, we have to extend -the <tt>PrototypeAST</tt> AST node like this:</p> - -<div class="doc_code"> -<pre> -/// PrototypeAST - This class represents the "prototype" for a function, -/// which captures its argument names as well as if it is an operator. -class PrototypeAST { - std::string Name; - std::vector<std::string> Args; - <b>bool isOperator; - unsigned Precedence; // Precedence if a binary op.</b> -public: - PrototypeAST(const std::string &name, const std::vector<std::string> &args, - <b>bool isoperator = false, unsigned prec = 0</b>) - : Name(name), Args(args), <b>isOperator(isoperator), Precedence(prec)</b> {} - - <b>bool isUnaryOp() const { return isOperator && Args.size() == 1; } - bool isBinaryOp() const { return isOperator && Args.size() == 2; } - - char getOperatorName() const { - assert(isUnaryOp() || isBinaryOp()); - return Name[Name.size()-1]; - } - - unsigned getBinaryPrecedence() const { return Precedence; }</b> - - Function *Codegen(); -}; -</pre> -</div> - -<p>Basically, in addition to knowing a name for the prototype, we now keep track -of whether it was an operator, and if it was, what precedence level the operator -is at. The precedence is only used for binary operators (as you'll see below, -it just doesn't apply for unary operators). Now that we have a way to represent -the prototype for a user-defined operator, we need to parse it:</p> - -<div class="doc_code"> -<pre> -/// prototype -/// ::= id '(' id* ')' -<b>/// ::= binary LETTER number? (id, id)</b> -static PrototypeAST *ParsePrototype() { - std::string FnName; - - <b>unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary. - unsigned BinaryPrecedence = 30;</b> - - switch (CurTok) { - default: - return ErrorP("Expected function name in prototype"); - case tok_identifier: - FnName = IdentifierStr; - Kind = 0; - getNextToken(); - break; - <b>case tok_binary: - getNextToken(); - if (!isascii(CurTok)) - return ErrorP("Expected binary operator"); - FnName = "binary"; - FnName += (char)CurTok; - Kind = 2; - getNextToken(); - - // Read the precedence if present. - if (CurTok == tok_number) { - if (NumVal < 1 || NumVal > 100) - return ErrorP("Invalid precedecnce: must be 1..100"); - BinaryPrecedence = (unsigned)NumVal; - getNextToken(); - } - break;</b> - } - - if (CurTok != '(') - return ErrorP("Expected '(' in prototype"); - - std::vector<std::string> ArgNames; - while (getNextToken() == tok_identifier) - ArgNames.push_back(IdentifierStr); - if (CurTok != ')') - return ErrorP("Expected ')' in prototype"); - - // success. - getNextToken(); // eat ')'. - - <b>// Verify right number of names for operator. - if (Kind && ArgNames.size() != Kind) - return ErrorP("Invalid number of operands for operator"); - - return new PrototypeAST(FnName, ArgNames, Kind != 0, BinaryPrecedence);</b> -} -</pre> -</div> - -<p>This is all fairly straightforward parsing code, and we have already seen -a lot of similar code in the past. One interesting part about the code above is -the couple lines that set up <tt>FnName</tt> for binary operators. This builds names -like "binary@" for a newly defined "@" operator. This then takes advantage of the -fact that symbol names in the LLVM symbol table are allowed to have any character in -them, including embedded nul characters.</p> - -<p>The next interesting thing to add, is codegen support for these binary operators. -Given our current structure, this is a simple addition of a default case for our -existing binary operator node:</p> - -<div class="doc_code"> -<pre> -Value *BinaryExprAST::Codegen() { - Value *L = LHS->Codegen(); - Value *R = RHS->Codegen(); - if (L == 0 || R == 0) return 0; - - switch (Op) { - case '+': return Builder.CreateFAdd(L, R, "addtmp"); - case '-': return Builder.CreateFSub(L, R, "subtmp"); - case '*': return Builder.CreateFMul(L, R, "multmp"); - case '<': - L = Builder.CreateFCmpULT(L, R, "cmptmp"); - // Convert bool 0/1 to double 0.0 or 1.0 - return Builder.CreateUIToFP(L, Type::getDoubleTy(getGlobalContext()), - "booltmp"); - <b>default: break;</b> - } - - <b>// If it wasn't a builtin binary operator, it must be a user defined one. Emit - // a call to it. - Function *F = TheModule->getFunction(std::string("binary")+Op); - assert(F && "binary operator not found!"); - - Value *Ops[2] = { L, R }; - return Builder.CreateCall(F, Ops, "binop");</b> -} - -</pre> -</div> - -<p>As you can see above, the new code is actually really simple. It just does -a lookup for the appropriate operator in the symbol table and generates a -function call to it. Since user-defined operators are just built as normal -functions (because the "prototype" boils down to a function with the right -name) everything falls into place.</p> - -<p>The final piece of code we are missing, is a bit of top-level magic:</p> - -<div class="doc_code"> -<pre> -Function *FunctionAST::Codegen() { - NamedValues.clear(); - - Function *TheFunction = Proto->Codegen(); - if (TheFunction == 0) - return 0; - - <b>// If this is an operator, install it. - if (Proto->isBinaryOp()) - BinopPrecedence[Proto->getOperatorName()] = Proto->getBinaryPrecedence();</b> - - // Create a new basic block to start insertion into. - BasicBlock *BB = BasicBlock::Create(getGlobalContext(), "entry", TheFunction); - Builder.SetInsertPoint(BB); - - if (Value *RetVal = Body->Codegen()) { - ... -</pre> -</div> - -<p>Basically, before codegening a function, if it is a user-defined operator, we -register it in the precedence table. This allows the binary operator parsing -logic 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> - -<p>Now we have useful user-defined binary operators. This builds a lot -on the previous framework we built for other operators. Adding unary operators -is a bit more challenging, because we don't have any framework for it yet - lets -see what it takes.</p> - -</div> - -<!-- *********************************************************************** --> -<h2><a name="unary">User-defined Unary Operators</a></h2> -<!-- *********************************************************************** --> - -<div> - -<p>Since we don't currently support unary operators in the Kaleidoscope -language, we'll need to add everything to support them. Above, we added simple -support for the 'unary' keyword to the lexer. In addition to that, we need an -AST node:</p> - -<div class="doc_code"> -<pre> -/// UnaryExprAST - Expression class for a unary operator. -class UnaryExprAST : public ExprAST { - char Opcode; - ExprAST *Operand; -public: - UnaryExprAST(char opcode, ExprAST *operand) - : Opcode(opcode), Operand(operand) {} - virtual Value *Codegen(); -}; -</pre> -</div> - -<p>This AST node is very simple and obvious by now. It directly mirrors the -binary operator AST node, except that it only has one child. With this, we -need to add the parsing logic. Parsing a unary operator is pretty simple: we'll -add a new function to do it:</p> - -<div class="doc_code"> -<pre> -/// unary -/// ::= primary -/// ::= '!' unary -static ExprAST *ParseUnary() { - // If the current token is not an operator, it must be a primary expr. - if (!isascii(CurTok) || CurTok == '(' || CurTok == ',') - return ParsePrimary(); - - // If this is a unary operator, read it. - int Opc = CurTok; - getNextToken(); - if (ExprAST *Operand = ParseUnary()) - return new UnaryExprAST(Opc, Operand); - return 0; -} -</pre> -</div> - -<p>The grammar we add is pretty straightforward here. If we see a unary -operator when parsing a primary operator, we eat the operator as a prefix and -parse the remaining piece as another unary operator. This allows us to handle -multiple unary operators (e.g. "!!x"). Note that unary operators can't have -ambiguous parses like binary operators can, so there is no need for precedence -information.</p> - -<p>The problem with this function, is that we need to call ParseUnary from somewhere. -To do this, we change previous callers of ParsePrimary to call ParseUnary -instead:</p> - -<div class="doc_code"> -<pre> -/// binoprhs -/// ::= ('+' unary)* -static ExprAST *ParseBinOpRHS(int ExprPrec, ExprAST *LHS) { - ... - <b>// Parse the unary expression after the binary operator. - ExprAST *RHS = ParseUnary(); - if (!RHS) return 0;</b> - ... -} -/// expression -/// ::= unary binoprhs -/// -static ExprAST *ParseExpression() { - <b>ExprAST *LHS = ParseUnary();</b> - if (!LHS) return 0; - - return ParseBinOpRHS(0, LHS); -} -</pre> -</div> - -<p>With these two simple changes, we are now able to parse unary operators and build the -AST for them. Next up, we need to add parser support for prototypes, to parse -the unary operator prototype. We extend the binary operator code above -with:</p> - -<div class="doc_code"> -<pre> -/// prototype -/// ::= id '(' id* ')' -/// ::= binary LETTER number? (id, id) -<b>/// ::= unary LETTER (id)</b> -static PrototypeAST *ParsePrototype() { - std::string FnName; - - unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary. - unsigned BinaryPrecedence = 30; - - switch (CurTok) { - default: - return ErrorP("Expected function name in prototype"); - case tok_identifier: - FnName = IdentifierStr; - Kind = 0; - getNextToken(); - break; - <b>case tok_unary: - getNextToken(); - if (!isascii(CurTok)) - return ErrorP("Expected unary operator"); - FnName = "unary"; - FnName += (char)CurTok; - Kind = 1; - getNextToken(); - break;</b> - case tok_binary: - ... -</pre> -</div> - -<p>As with binary operators, we name unary operators with a name that includes -the operator character. This assists us at code generation time. Speaking of, -the final piece we need to add is codegen support for unary operators. It looks -like this:</p> - -<div class="doc_code"> -<pre> -Value *UnaryExprAST::Codegen() { - Value *OperandV = Operand->Codegen(); - if (OperandV == 0) return 0; - - Function *F = TheModule->getFunction(std::string("unary")+Opcode); - if (F == 0) - return ErrorV("Unknown unary operator"); - - return Builder.CreateCall(F, OperandV, "unop"); -} -</pre> -</div> - -<p>This code is similar to, but simpler than, the code for binary operators. It -is simpler primarily because it doesn't need to handle any predefined operators. -</p> - -</div> - -<!-- *********************************************************************** --> -<h2><a name="example">Kicking the Tires</a></h2> -<!-- *********************************************************************** --> - -<div> - -<p>It is somewhat hard to believe, but with a few simple extensions we've -covered in the last chapters, we have grown a real-ish language. With this, we -can do a lot of interesting things, including I/O, math, and a bunch of other -things. For example, we can now add a nice sequencing operator (printd is -defined to print out the specified value and a newline):</p> - -<div class="doc_code"> -<pre> -ready> <b>extern printd(x);</b> -Read extern: -declare double @printd(double) - -ready> <b>def binary : 1 (x y) 0; # Low-precedence operator that ignores operands.</b> -.. -ready> <b>printd(123) : printd(456) : printd(789);</b> -123.000000 -456.000000 -789.000000 -Evaluated to 0.000000 -</pre> -</div> - -<p>We can also define a bunch of other "primitive" operations, such as:</p> - -<div class="doc_code"> -<pre> -# Logical unary not. -def unary!(v) - if v then - 0 - else - 1; - -# Unary negate. -def unary-(v) - 0-v; - -# Define > with the same precedence as <. -def binary> 10 (LHS RHS) - RHS < LHS; - -# Binary logical or, which does not short circuit. -def binary| 5 (LHS RHS) - if LHS then - 1 - else if RHS then - 1 - else - 0; - -# Binary logical and, which does not short circuit. -def binary& 6 (LHS RHS) - if !LHS then - 0 - else - !!RHS; - -# Define = with slightly lower precedence than relationals. -def binary = 9 (LHS RHS) - !(LHS < RHS | LHS > RHS); - -# Define ':' for sequencing: as a low-precedence operator that ignores operands -# and just returns the RHS. -def binary : 1 (x y) y; -</pre> -</div> - - -<p>Given the previous if/then/else support, we can also define interesting -functions for I/O. For example, the following prints out a character whose -"density" reflects the value passed in: the lower the value, the denser the -character:</p> - -<div class="doc_code"> -<pre> -ready> -<b> -extern putchard(char) -def printdensity(d) - if d > 8 then - putchard(32) # ' ' - else if d > 4 then - putchard(46) # '.' - else if d > 2 then - putchard(43) # '+' - else - putchard(42); # '*'</b> -... -ready> <b>printdensity(1): printdensity(2): printdensity(3): - printdensity(4): printdensity(5): printdensity(9): - putchard(10);</b> -**++. -Evaluated to 0.000000 -</pre> -</div> - -<p>Based on these simple primitive operations, we can start to define more -interesting things. For example, here's a little function that solves for the -number of iterations it takes a function in the complex plane to -converge:</p> - -<div class="doc_code"> -<pre> -# Determine whether the specific location diverges. -# Solve for z = z^2 + c in the complex plane. -def mandleconverger(real imag iters creal cimag) - if iters > 255 | (real*real + imag*imag > 4) then - iters - else - mandleconverger(real*real - imag*imag + creal, - 2*real*imag + cimag, - iters+1, creal, cimag); - -# Return the number of iterations required for the iteration to escape -def mandleconverge(real imag) - mandleconverger(real, imag, 0, real, imag); -</pre> -</div> - -<p>This "<code>z = z<sup>2</sup> + c</code>" function is a beautiful little -creature that is the basis for computation of -the <a href="http://en.wikipedia.org/wiki/Mandelbrot_set">Mandelbrot Set</a>. -Our <tt>mandelconverge</tt> function returns the number of iterations that it -takes for a complex orbit to escape, saturating to 255. This is not a very -useful function by itself, but if you plot its value over a two-dimensional -plane, you can see the Mandelbrot set. Given that we are limited to using -putchard here, our amazing graphical output is limited, but we can whip together -something using the density plotter above:</p> - -<div class="doc_code"> -<pre> -# Compute and plot the mandlebrot set with the specified 2 dimensional range -# info. -def mandelhelp(xmin xmax xstep ymin ymax ystep) - for y = ymin, y < ymax, ystep in ( - (for x = xmin, x < xmax, xstep in - printdensity(mandleconverge(x,y))) - : putchard(10) - ) - -# mandel - This is a convenient helper function for plotting the mandelbrot set -# from the specified position with the specified Magnification. -def mandel(realstart imagstart realmag imagmag) - mandelhelp(realstart, realstart+realmag*78, realmag, - imagstart, imagstart+imagmag*40, imagmag); -</pre> -</div> - -<p>Given this, we can try plotting out the mandlebrot set! Lets try it out:</p> - -<div class="doc_code"> -<pre> -ready> <b>mandel(-2.3, -1.3, 0.05, 0.07);</b> -*******************************+++++++++++************************************* -*************************+++++++++++++++++++++++******************************* -**********************+++++++++++++++++++++++++++++**************************** -*******************+++++++++++++++++++++.. ...++++++++************************* -*****************++++++++++++++++++++++.... ...+++++++++*********************** -***************+++++++++++++++++++++++..... ...+++++++++********************* -**************+++++++++++++++++++++++.... ....+++++++++******************** -*************++++++++++++++++++++++...... .....++++++++******************* -************+++++++++++++++++++++....... .......+++++++****************** -***********+++++++++++++++++++.... ... .+++++++***************** -**********+++++++++++++++++....... .+++++++**************** -*********++++++++++++++........... ...+++++++*************** -********++++++++++++............ ...++++++++************** -********++++++++++... .......... .++++++++************** -*******+++++++++..... .+++++++++************* -*******++++++++...... ..+++++++++************* -*******++++++....... ..+++++++++************* -*******+++++...... ..+++++++++************* -*******.... .... ...+++++++++************* -*******.... . ...+++++++++************* -*******+++++...... ...+++++++++************* -*******++++++....... ..+++++++++************* -*******++++++++...... .+++++++++************* -*******+++++++++..... ..+++++++++************* -********++++++++++... .......... .++++++++************** -********++++++++++++............ ...++++++++************** -*********++++++++++++++.......... ...+++++++*************** -**********++++++++++++++++........ .+++++++**************** -**********++++++++++++++++++++.... ... ..+++++++**************** -***********++++++++++++++++++++++....... .......++++++++***************** -************+++++++++++++++++++++++...... ......++++++++****************** -**************+++++++++++++++++++++++.... ....++++++++******************** -***************+++++++++++++++++++++++..... ...+++++++++********************* -*****************++++++++++++++++++++++.... ...++++++++*********************** -*******************+++++++++++++++++++++......++++++++************************* -*********************++++++++++++++++++++++.++++++++*************************** -*************************+++++++++++++++++++++++******************************* -******************************+++++++++++++************************************ -******************************************************************************* -******************************************************************************* -******************************************************************************* -Evaluated to 0.000000 -ready> <b>mandel(-2, -1, 0.02, 0.04);</b> -**************************+++++++++++++++++++++++++++++++++++++++++++++++++++++ -***********************++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -*********************+++++++++++++++++++++++++++++++++++++++++++++++++++++++++. -*******************+++++++++++++++++++++++++++++++++++++++++++++++++++++++++... -*****************+++++++++++++++++++++++++++++++++++++++++++++++++++++++++..... -***************++++++++++++++++++++++++++++++++++++++++++++++++++++++++........ -**************++++++++++++++++++++++++++++++++++++++++++++++++++++++........... -************+++++++++++++++++++++++++++++++++++++++++++++++++++++.............. -***********++++++++++++++++++++++++++++++++++++++++++++++++++........ . -**********++++++++++++++++++++++++++++++++++++++++++++++............. -********+++++++++++++++++++++++++++++++++++++++++++.................. -*******+++++++++++++++++++++++++++++++++++++++....................... -******+++++++++++++++++++++++++++++++++++........................... -*****++++++++++++++++++++++++++++++++............................ -*****++++++++++++++++++++++++++++............................... -****++++++++++++++++++++++++++...... ......................... -***++++++++++++++++++++++++......... ...... ........... -***++++++++++++++++++++++............ -**+++++++++++++++++++++.............. -**+++++++++++++++++++................ -*++++++++++++++++++................. -*++++++++++++++++............ ... -*++++++++++++++.............. -*+++....++++................ -*.......... ........... -* -*.......... ........... -*+++....++++................ -*++++++++++++++.............. -*++++++++++++++++............ ... -*++++++++++++++++++................. -**+++++++++++++++++++................ -**+++++++++++++++++++++.............. -***++++++++++++++++++++++............ -***++++++++++++++++++++++++......... ...... ........... -****++++++++++++++++++++++++++...... ......................... -*****++++++++++++++++++++++++++++............................... -*****++++++++++++++++++++++++++++++++............................ -******+++++++++++++++++++++++++++++++++++........................... -*******+++++++++++++++++++++++++++++++++++++++....................... -********+++++++++++++++++++++++++++++++++++++++++++.................. -Evaluated to 0.000000 -ready> <b>mandel(-0.9, -1.4, 0.02, 0.03);</b> -******************************************************************************* -******************************************************************************* -******************************************************************************* -**********+++++++++++++++++++++************************************************ -*+++++++++++++++++++++++++++++++++++++++*************************************** -+++++++++++++++++++++++++++++++++++++++++++++********************************** -++++++++++++++++++++++++++++++++++++++++++++++++++***************************** -++++++++++++++++++++++++++++++++++++++++++++++++++++++************************* -+++++++++++++++++++++++++++++++++++++++++++++++++++++++++********************** -+++++++++++++++++++++++++++++++++.........++++++++++++++++++******************* -+++++++++++++++++++++++++++++++.... ......+++++++++++++++++++**************** -+++++++++++++++++++++++++++++....... ........+++++++++++++++++++************** -++++++++++++++++++++++++++++........ ........++++++++++++++++++++************ -+++++++++++++++++++++++++++......... .. ...+++++++++++++++++++++********** -++++++++++++++++++++++++++........... ....++++++++++++++++++++++******** -++++++++++++++++++++++++............. .......++++++++++++++++++++++****** -+++++++++++++++++++++++............. ........+++++++++++++++++++++++**** -++++++++++++++++++++++........... ..........++++++++++++++++++++++*** -++++++++++++++++++++........... .........++++++++++++++++++++++* -++++++++++++++++++............ ...........++++++++++++++++++++ -++++++++++++++++............... .............++++++++++++++++++ -++++++++++++++................. ...............++++++++++++++++ -++++++++++++.................. .................++++++++++++++ -+++++++++.................. .................+++++++++++++ -++++++........ . ......... ..++++++++++++ -++............ ...... ....++++++++++ -.............. ...++++++++++ -.............. ....+++++++++ -.............. .....++++++++ -............. ......++++++++ -........... .......++++++++ -......... ........+++++++ -......... ........+++++++ -......... ....+++++++ -........ ...+++++++ -....... ...+++++++ - ....+++++++ - .....+++++++ - ....+++++++ - ....+++++++ - ....+++++++ -Evaluated to 0.000000 -ready> <b>^D</b> -</pre> -</div> - -<p>At this point, you may be starting to realize that Kaleidoscope is a real -and powerful language. It may not be self-similar :), but it can be used to -plot things that are!</p> - -<p>With this, we conclude the "adding user-defined operators" chapter of the -tutorial. We have successfully augmented our language, adding the ability to extend the -language in the library, and we have shown how this can be used to build a simple but -interesting end-user application in Kaleidoscope. At this point, Kaleidoscope -can build a variety of applications that are functional and can call functions -with side-effects, but it can't actually define and mutate a variable itself. -</p> - -<p>Strikingly, variable mutation is an important feature of some -languages, and it is not at all obvious how to <a href="LangImpl7.html">add -support for mutable variables</a> without having to add an "SSA construction" -phase to your front-end. In the next chapter, we will describe how you can -add variable mutation without building SSA in your front-end.</p> - -</div> - -<!-- *********************************************************************** --> -<h2><a name="code">Full Code Listing</a></h2> -<!-- *********************************************************************** --> - -<div> - -<p> -Here is the complete code listing for our running example, enhanced with the -if/then/else and for expressions.. To build this example, use: -</p> - -<div class="doc_code"> -<pre> -# Compile -clang++ -g toy.cpp `llvm-config --cppflags --ldflags --libs core jit native` -O3 -o toy -# Run -./toy -</pre> -</div> - -<p>On some platforms, you will need to specify -rdynamic or -Wl,--export-dynamic -when linking. This ensures that symbols defined in the main executable are -exported to the dynamic linker and so are available for symbol resolution at -run time. This is not needed if you compile your support code into a shared -library, although doing that will cause problems on Windows.</p> - -<p>Here is the code:</p> - -<div class="doc_code"> -<pre> -#include "llvm/DerivedTypes.h" -#include "llvm/ExecutionEngine/ExecutionEngine.h" -#include "llvm/ExecutionEngine/JIT.h" -#include "llvm/IRBuilder.h" -#include "llvm/LLVMContext.h" -#include "llvm/Module.h" -#include "llvm/PassManager.h" -#include "llvm/Analysis/Verifier.h" -#include "llvm/Analysis/Passes.h" -#include "llvm/DataLayout.h" -#include "llvm/Transforms/Scalar.h" -#include "llvm/Support/TargetSelect.h" -#include <cstdio> -#include <string> -#include <map> -#include <vector> -using namespace llvm; - -//===----------------------------------------------------------------------===// -// Lexer -//===----------------------------------------------------------------------===// - -// The lexer returns tokens [0-255] if it is an unknown character, otherwise one -// of these for known things. -enum Token { - tok_eof = -1, - - // commands - tok_def = -2, tok_extern = -3, - - // primary - tok_identifier = -4, tok_number = -5, - - // control - tok_if = -6, tok_then = -7, tok_else = -8, - tok_for = -9, tok_in = -10, - - // operators - tok_binary = -11, tok_unary = -12 -}; - -static std::string IdentifierStr; // Filled in if tok_identifier -static double NumVal; // Filled in if tok_number - -/// gettok - Return the next token from standard input. -static int gettok() { - static int LastChar = ' '; - - // Skip any whitespace. - while (isspace(LastChar)) - LastChar = getchar(); - - if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]* - IdentifierStr = LastChar; - while (isalnum((LastChar = getchar()))) - IdentifierStr += LastChar; - - if (IdentifierStr == "def") return tok_def; - if (IdentifierStr == "extern") return tok_extern; - if (IdentifierStr == "if") return tok_if; - if (IdentifierStr == "then") return tok_then; - if (IdentifierStr == "else") return tok_else; - if (IdentifierStr == "for") return tok_for; - if (IdentifierStr == "in") return tok_in; - if (IdentifierStr == "binary") return tok_binary; - if (IdentifierStr == "unary") return tok_unary; - return tok_identifier; - } - - if (isdigit(LastChar) || LastChar == '.') { // Number: [0-9.]+ - std::string NumStr; - do { - NumStr += LastChar; - LastChar = getchar(); - } while (isdigit(LastChar) || LastChar == '.'); - - NumVal = strtod(NumStr.c_str(), 0); - return tok_number; - } - - if (LastChar == '#') { - // Comment until end of line. - do LastChar = getchar(); - while (LastChar != EOF && LastChar != '\n' && LastChar != '\r'); - - if (LastChar != EOF) - return gettok(); - } - - // Check for end of file. Don't eat the EOF. - if (LastChar == EOF) - return tok_eof; - - // Otherwise, just return the character as its ascii value. - int ThisChar = LastChar; - LastChar = |