[llvm-commits] [llvm] r43213 - in /llvm/trunk/docs/tutorial: JITTutorial1.html Tutorial1.html index.html
Chris Lattner
sabre at nondot.org
Sun Oct 21 20:12:26 PDT 2007
Author: lattner
Date: Sun Oct 21 22:12:24 2007
New Revision: 43213
URL: http://llvm.org/viewvc/llvm-project?rev=43213&view=rev
Log:
rename tutorial 1 -> JITTutorial1, make unimplemented links not be dead links.
Added:
llvm/trunk/docs/tutorial/JITTutorial1.html
- copied unchanged from r43212, llvm/trunk/docs/tutorial/Tutorial1.html
Removed:
llvm/trunk/docs/tutorial/Tutorial1.html
Modified:
llvm/trunk/docs/tutorial/index.html
Removed: llvm/trunk/docs/tutorial/Tutorial1.html
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/tutorial/Tutorial1.html?rev=43212&view=auto
==============================================================================
--- llvm/trunk/docs/tutorial/Tutorial1.html (original)
+++ llvm/trunk/docs/tutorial/Tutorial1.html (removed)
@@ -1,156 +0,0 @@
-<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
- "http://www.w3.org/TR/html4/strict.dtd">
-
-<html>
-<head>
- <title>LLVM Tutorial 1: A First Function</title>
- <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
- <meta name="author" content="Owen Anderson">
- <meta name="description"
- content="LLVM Tutorial 1: A First Function.">
- <link rel="stylesheet" href="../llvm.css" type="text/css">
-</head>
-
-<body>
-
-<div class="doc_title"> LLVM Tutorial 1: A First Function </div>
-
-<div class="doc_author">
- <p>Written by <a href="mailto:owen at apple.com">Owen Anderson</a></p>
-</div>
-
-<div class="doc_text">
-
-<p>For starters, lets consider a relatively straightforward function that takes three integer parameters and returns an arithmetic combination of them. This is nice and simple, especially since it involves no control flow:</p>
-
-<div class="doc_code">
-<pre>
-int mul_add(int x, int y, int z) {
- return x * y + z;
-}
-</pre>
-</div>
-
-<p>As a preview, the LLVM IR weâre going to end up generating for this function will look like:</p>
-
-<div class="doc_code">
-<pre>
-define i32 @mul_add(i32 %x, i32 %y, i32 %z) {
-entry:
- %tmp = mul i32 %x, %y
- %tmp2 = add i32 %tmp, %z
- ret i32 %tmp2
-}
-</pre>
-</div>
-
-<p>If you're unsure what the above code says, skim through the <a href="../LangRef.html">LLVM Language Reference Manual</a> and convince yourself that the above LLVM IR is actually equivalent to the original function. Once youâre satisfied with that, letâs move on to actually generating it programmatically!</p>
-
-<p>... STUFF ABOUT HEADERS ... </p>
-
-<p>Now, letâs get started on our real program. Hereâs what our basic <code>main()</code> will look like:</p>
-
-<div class="doc_code">
-<pre>
-using namespace llvm;
-
-Module* makeLLVMModule();
-
-int main(int argc, char**argv) {
- Module* Mod = makeLLVMModule();
-
- verifyModule(*Mod, PrintMessageAction);
-
- PassManager PM;
- PM.add(new PrintModulePass(&llvm::cout));
- PM.run(*Mod);
-
- return 0;
-}
-</pre>
-</div>
-
-<p>The first segment is pretty simple: it creates an LLVM âmodule.â In LLVM, a module represents a single unit of code that is to be processed together. A module contains things like global variables and function declarations and implementations. Here, weâve declared a <code>makeLLVMModule()</code> function to do the real work of creating the module. Donât worry, weâll be looking at that one next!</p>
-
-<p>The second segment runs the LLVM module verifier on our newly created module. While this probably isnât really necessary for a simple module like this one, itâs always a good idea, especially if youâre generating LLVM IR based on some input. The verifier will print an error message if your LLVM module is malformed in any way.</p>
-
-<p>Finally, we instantiate an LLVM <code>PassManager</code> and run the <code>PrintModulePass</code> on our module. LLVM uses an explicit pass infrastructure to manage optimizations and various other things. A <code>PassManager</code>, as should be obvious from its name, manages passes: it is responsible for scheduling them, invoking them, and insuring the proper disposal after weâre done with them. For this example, weâre just using a trivial pass that prints out our module in textual form.</p>
-
-<p>Now onto the interesting part: creating a populating a module. Hereâs the first chunk of our <code>makeLLVMModule()</code>:</p>
-
-<div class="doc_code">
-<pre>
-Module* makeLLVMModule() {
- // Module Construction
- Module* mod = new Module("test");
-</pre>
-</div>
-
-<p>Exciting, isnât it!? All weâre doing here is instantiating a module and giving it a name. The name isnât particularly important unless youâre going to be dealing with multiple modules at once.</p>
-
-<div class="doc_code">
-<pre>
- Constant* c->getOrInsertFunction("mul_add",
- /*ret type*/ IntegerType::get(32),
- /*args*/ IntegerType::get(32),
- IntegerType::get(32),
- IntegerType::get(32));
-
- Function* mul_add = cast<Function>(c);
- mul_add->setCallingConv(CallingConv::C);
-</pre>
-</div>
-
-<p>We construct our <code>Function</code> by calling <code>getOrInsertFunction()</code> on our module, passing in the name, return type, and argument types of the function. In the case of our <code>mul_add</code> function, that means one 32-bit integer for the return value, and three 32-bit integers for the arguments.</p>
-
-<p>You'll notice that <code>getOrInsertFunction</code> doesn't actually return a <code>Function*</code>. This is because, if the function already existed, but with a different prototype, <code>getOrInsertFunction</code> will return a cast of the existing function to the desired prototype. Since we know that there's not already a <code>mul_add</code> function, we can safely just cast <code>c</code> to a <code>Function*</code>.
-
-<p>In addition, we set the calling convention for our new function to be the C calling convention. This isnât strictly necessary, but it insures that our new function will interoperate properly with C code, which is a good thing.</p>
-
-<div class="doc_code">
-<pre>
- Function::arg_iterator args = mul_add->arg_begin();
- Value* x = args++;
- x->setName("x");
- Value* y = args++;
- y->setName("y");
- Value* z = args++;
- z->setName("z");
-</pre>
-</div>
-
-<p>While weâre setting up our function, letâs also give names to the parameters. This also isnât strictly necessary (LLVM will generate names for them if you donât specify them), but itâll make looking at our output somewhat more pleasant. To name the parameters, we iterator over the arguments of our function, and call <code>setName()</code> on them. Weâll also keep the pointer to <code>x</code>, <code>y</code>, and <code>z</code> around, since weâll need them when we get around to creating instructions.</p>
-
-<p>Great! We have a function now. But what good is a function if it has no body? Before we start working on a body for our new function, we need to recall some details of the LLVM IR. The IR, being an abstract assembly language, represents control flow using jumps (we call them branches), both conditional and unconditional. The straight-line sequences of code between branches are called basic blocks, or just blocks. To create a body for our function, we fill it with blocks!</p>
-
-<div class="doc_code">
-<pre>
- BasicBlock* block = new BasicBlock("entry", mul_add);
- LLVMBuilder builder(block);
-</pre>
-</div>
-
-<p>We create a new basic block, as you might expect, by calling its constructor. All we need to tell it is its name and the function to which it belongs. In addition, weâre creating an <code>LLVMBuilder</code> object, which is a convenience interface for creating instructions and appending them to the end of a block. Instructions can be created through their constructors as well, but some of their interfaces are quite complicated. Unless you need a lot of control, using <code>LLVMBuilder</code> will make your life simpler.</p>
-
-<div class="doc_code">
-<pre>
- Value* tmp = builder.CreateBinOp(Instruction::Mul,
- x, y, "tmp");
- Value* tmp2 = builder.CreateBinOp(Instruction::Add,
- tmp, z, "tmp2");
-
- builder.CreateRet(tmp2);
-}
-</pre>
-</div>
-
-<p>The final step in creating our function is to create the instructions that make it up. Our <code>mul_add</code> function is composed of just three instructions: a multiply, an add, and a return. <code>LLVMBuilder</code> gives us a simple interface for constructing these instructions and appending them to the âentryâ block. Each of the calls to <code>LLVMBuilder</code> returns a <code>Value*</code> that represents the value yielded by the instruction. Youâll also notice that, above, <code>x</code>, <code>y</code>, and <code>z</code> are also <code>Value*</code>âs, so itâs clear that instructions operate on <code>Value*</code>âs.</p>
-
-<p>And thatâs it! Now you can compile and run your code, and get a wonder textual print out of the LLVM IR we saw at the beginning.</p>
-
-<p> ... SECTION ABOUT USING llvm-config TO GET THE NECESSARY COMPILER FLAGS TO COMPILE YOUR CODE ... </p>
-
-</div>
-
-</body>
-</html>
\ No newline at end of file
Modified: llvm/trunk/docs/tutorial/index.html
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/tutorial/index.html?rev=43213&r1=43212&r2=43213&view=diff
==============================================================================
--- llvm/trunk/docs/tutorial/index.html (original)
+++ llvm/trunk/docs/tutorial/index.html Sun Oct 21 22:12:24 2007
@@ -18,11 +18,11 @@
<li><a href="Introduction.html">An Introduction to LLVM: Basic Concepts and Design</a></li>
<li>Basic Tutorials
<ol>
- <li><a href="Tutorial1.html">Tutorial 1: A First Function</a></li>
- <li><a href="Tutorial2.html">Tutorial 2: A More Complicated Function</a></li>
- <li><a href="Tutorial3.html">Tutorial 3: Reading and Writing Bitcode</a></li>
- <li><a href="Tutorial4.html">Tutorial 4: Running Optimizations</a></li>
- <li><a href="Tutorial5.html">Tutorial 5: Invoking the JIT</a></li>
+ <li><a href="JITTutorial1.html">Tutorial 1: A First Function</a></li>
+ <li><!--<a href="Tutorial2.html">-->Tutorial 2: A More Complicated Function</li>
+ <li><!--<a href="Tutorial3.html">-->Tutorial 3: Reading and Writing Bitcode</li>
+ <li><!--<a href="Tutorial4.html">-->Tutorial 4: Running Optimizations</li>
+ <li><!--<a href="Tutorial5.html">-->Tutorial 5: Invoking the JIT</li>
</ol>
</li>
<li><a href="Example.html">Example: Using LLVM to execute a simple language in JIT</a></li>
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