<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="author" content="Chris Lattner">
<meta name="author" content="Erick Tryzelaar">
- <link rel="stylesheet" href="../llvm.css" type="text/css">
+ <link rel="stylesheet" href="../_static/llvm.css" type="text/css">
</head>
<body>
-<div class="doc_title">Kaleidoscope: Code generation to LLVM IR</div>
+<h1>Kaleidoscope: Code generation to LLVM IR</h1>
<ul>
<li><a href="index.html">Up to Tutorial Index</a></li>
<li><a href="#code">Full Code Listing</a></li>
</ol>
</li>
-<li><a href="LangImpl4.html">Chapter 4</a>: Adding JIT and Optimizer
+<li><a href="OCamlLangImpl4.html">Chapter 4</a>: Adding JIT and Optimizer
Support</li>
</ul>
</div>
<!-- *********************************************************************** -->
-<div class="doc_section"><a name="intro">Chapter 3 Introduction</a></div>
+<h2><a name="intro">Chapter 3 Introduction</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>Welcome to Chapter 3 of the "<a href="index.html">Implementing a language
with LLVM</a>" tutorial. This chapter shows you how to transform the <a
</div>
<!-- *********************************************************************** -->
-<div class="doc_section"><a name="basics">Code Generation Setup</a></div>
+<h2><a name="basics">Code Generation Setup</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>
In order to generate LLVM IR, we want some simple setup to get started. First
<pre>
exception Error of string
-let the_module = create_module "my cool jit"
-let builder = builder ()
+let context = global_context ()
+let the_module = create_module context "my cool jit"
+let builder = builder context
let named_values:(string, llvalue) Hashtbl.t = Hashtbl.create 10
+let double_type = double_type context
</pre>
</div>
</div>
<!-- *********************************************************************** -->
-<div class="doc_section"><a name="exprs">Expression Code Generation</a></div>
+<h2><a name="exprs">Expression Code Generation</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>Generating LLVM code for expression nodes is very straightforward: less
than 30 lines of commented code for all four of our expression nodes. First
constants of <em>A</em>rbitrary <em>P</em>recision). This code basically just
creates and returns a <tt>ConstantFP</tt>. Note that in the LLVM IR
that constants are all uniqued together and shared. For this reason, the API
-uses "the foo::get(..)" idiom instead of "new foo(..)" or "foo::create(..)".</p>
+uses "the foo::get(..)" idiom instead of "new foo(..)" or "foo::Create(..)".</p>
<div class="doc_code">
<pre>
</div>
<p>References to variables are also quite simple using LLVM. In the simple
-version of Kaleidoscope, we assume that the variable has already been emited
+version of Kaleidoscope, we assume that the variable has already been emitted
somewhere and its value is available. In practice, the only values that can be
in the <tt>Codegen.named_values</tt> map are function arguments. This code
simply checks to see that the specified name is in the map (if not, an unknown
let rhs_val = codegen_expr rhs in
begin
match op with
- | '+' -> build_add lhs_val rhs_val "addtmp" builder
- | '-' -> build_sub lhs_val rhs_val "subtmp" builder
- | '*' -> build_mul lhs_val rhs_val "multmp" builder
+ | '+' -> build_fadd lhs_val rhs_val "addtmp" builder
+ | '-' -> build_fsub lhs_val rhs_val "subtmp" builder
+ | '*' -> build_fmul lhs_val rhs_val "multmp" builder
| '<' ->
(* Convert bool 0/1 to double 0.0 or 1.0 *)
let i = build_fcmp Fcmp.Ult lhs_val rhs_val "cmptmp" builder in
</div>
<!-- *********************************************************************** -->
-<div class="doc_section"><a name="funcs">Function Code Generation</a></div>
+<h2><a name="funcs">Function Code Generation</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>Code generation for prototypes and functions must handle a number of
details, which make their code less beautiful than expression code
first, we want to allow 'extern'ing a function more than once, as long as the
prototypes for the externs match (since all arguments have the same type, we
just have to check that the number of arguments match). Second, we want to
-allow 'extern'ing a function and then definining a body for it. This is useful
+allow 'extern'ing a function and then defining a body for it. This is useful
when defining mutually recursive functions.</p>
<div class="doc_code">
<div class="doc_code">
<pre>
(* Create a new basic block to start insertion into. *)
- let bb = append_block "entry" the_function in
+ let bb = append_block context "entry" the_function in
position_at_end bb builder;
try
</div>
<!-- *********************************************************************** -->
-<div class="doc_section"><a name="driver">Driver Changes and
-Closing Thoughts</a></div>
+<h2><a name="driver">Driver Changes and Closing Thoughts</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>
For now, code generation to LLVM doesn't really get us much, except that we can
Read top-level expression:
define double @""() {
entry:
- %addtmp = add double 4.000000e+00, 5.000000e+00
+ %addtmp = fadd double 4.000000e+00, 5.000000e+00
ret double %addtmp
}
</pre>
</div>
<p>Note how the parser turns the top-level expression into anonymous functions
-for us. This will be handy when we add <a href="LangImpl4.html#jit">JIT
+for us. This will be handy when we add <a href="OCamlLangImpl4.html#jit">JIT
support</a> in the next chapter. Also note that the code is very literally
transcribed, no optimizations are being performed. We will
<a href="OCamlLangImpl4.html#trivialconstfold">add optimizations</a> explicitly
Read function definition:
define double @foo(double %a, double %b) {
entry:
- %multmp = mul double %a, %a
- %multmp1 = mul double 2.000000e+00, %a
- %multmp2 = mul double %multmp1, %b
- %addtmp = add double %multmp, %multmp2
- %multmp3 = mul double %b, %b
- %addtmp4 = add double %addtmp, %multmp3
+ %multmp = fmul double %a, %a
+ %multmp1 = fmul double 2.000000e+00, %a
+ %multmp2 = fmul double %multmp1, %b
+ %addtmp = fadd double %multmp, %multmp2
+ %multmp3 = fmul double %b, %b
+ %addtmp4 = fadd double %addtmp, %multmp3
ret double %addtmp4
}
</pre>
Read function definition:
define double @bar(double %a) {
entry:
- %calltmp = call double @foo( double %a, double 4.000000e+00 )
- %calltmp1 = call double @bar( double 3.133700e+04 )
- %addtmp = add double %calltmp, %calltmp1
+ %calltmp = call double @foo(double %a, double 4.000000e+00)
+ %calltmp1 = call double @bar(double 3.133700e+04)
+ %addtmp = fadd double %calltmp, %calltmp1
ret double %addtmp
}
</pre>
Read top-level expression:
define double @""() {
entry:
- %calltmp = call double @cos( double 1.234000e+00 )
+ %calltmp = call double @cos(double 1.234000e+00)
ret double %calltmp
}
</pre>
define double @""() {
entry:
- %addtmp = add double 4.000000e+00, 5.000000e+00
+ %addtmp = fadd double 4.000000e+00, 5.000000e+00
ret double %addtmp
}
define double @foo(double %a, double %b) {
entry:
- %multmp = mul double %a, %a
- %multmp1 = mul double 2.000000e+00, %a
- %multmp2 = mul double %multmp1, %b
- %addtmp = add double %multmp, %multmp2
- %multmp3 = mul double %b, %b
- %addtmp4 = add double %addtmp, %multmp3
+ %multmp = fmul double %a, %a
+ %multmp1 = fmul double 2.000000e+00, %a
+ %multmp2 = fmul double %multmp1, %b
+ %addtmp = fadd double %multmp, %multmp2
+ %multmp3 = fmul double %b, %b
+ %addtmp4 = fadd double %addtmp, %multmp3
ret double %addtmp4
}
define double @bar(double %a) {
entry:
- %calltmp = call double @foo( double %a, double 4.000000e+00 )
- %calltmp1 = call double @bar( double 3.133700e+04 )
- %addtmp = add double %calltmp, %calltmp1
+ %calltmp = call double @foo(double %a, double 4.000000e+00)
+ %calltmp1 = call double @bar(double 3.133700e+04)
+ %addtmp = fadd double %calltmp, %calltmp1
ret double %addtmp
}
define double @""() {
entry:
- %calltmp = call double @cos( double 1.234000e+00 )
+ %calltmp = call double @cos(double 1.234000e+00)
ret double %calltmp
}
</pre>
each other.</p>
<p>This wraps up the third chapter of the Kaleidoscope tutorial. Up next, we'll
-describe how to <a href="LangImpl4.html">add JIT codegen and optimizer
+describe how to <a href="OCamlLangImpl4.html">add JIT codegen and optimizer
support</a> to this so we can actually start running code!</p>
</div>
<!-- *********************************************************************** -->
-<div class="doc_section"><a name="code">Full Code Listing</a></div>
+<h2><a name="code">Full Code Listing</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>
Here is the complete code listing for our running example, enhanced with the
exception Error of string
-let the_module = create_module "my cool jit"
-let builder = builder ()
+let context = global_context ()
+let the_module = create_module context "my cool jit"
+let builder = builder context
let named_values:(string, llvalue) Hashtbl.t = Hashtbl.create 10
+let double_type = double_type context
let rec codegen_expr = function
| Ast.Number n -> const_float double_type n
let the_function = codegen_proto proto in
(* Create a new basic block to start insertion into. *)
- let bb = append_block "entry" the_function in
+ let bb = append_block context "entry" the_function in
position_at_end bb builder;
try
<a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
<a href="mailto:idadesub@users.sourceforge.net">Erick Tryzelaar</a><br>
- <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
- Last modified: $Date: 2007-10-17 11:05:13 -0700 (Wed, 17 Oct 2007) $
+ <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
+ Last modified: $Date$
</address>
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