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Made document HTML-4.01 (Strict)-compliant.
llvm-svn: 13505
This commit is contained in:
Misha Brukman
parent
c1aac03803
commit
6eb0085f65
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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"http://www.w3.org/TR/html4/strict.dtd">
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<html>
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<head>
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<title>Stacker: An Example Of Using LLVM</title>
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<title>Stacker: An Example Of Using LLVM</title>
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<link rel="stylesheet" href="llvm.css" type="text/css">
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</head>
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<body>
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<div class="doc_title">Stacker: An Example Of Using LLVM</div>
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<hr>
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<ol>
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<li><a href="#abstract">Abstract</a></li>
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<li><a href="#introduction">Introduction</a></li>
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@ -19,19 +21,17 @@
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<li><a href="#gep">The Wily GetElementPtrInst</a></li>
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<li><a href="#linkage">Getting Linkage Types Right</a></li>
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<li><a href="#constants">Constants Are Easier Than That!</a></li>
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</ol>
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</li>
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</ol></li>
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<li><a href="#lexicon">The Stacker Lexicon</a>
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<ol>
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<li><a href="#stack">The Stack</a>
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<li><a href="#punctuation">Punctuation</a>
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<li><a href="#comments">Comments</a>
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<li><a href="#literals">Literals</a>
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<li><a href="#words">Words</a>
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<li><a href="style">Standard Style</a>
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<li><a href="#builtins">Built-Ins</a>
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</ol>
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</li>
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<li><a href="#stack">The Stack</a></li>
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<li><a href="#punctuation">Punctuation</a></li>
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<li><a href="#comments">Comments</a></li>
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<li><a href="#literals">Literals</a></li>
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<li><a href="#words">Words</a></li>
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<li><a href="style">Standard Style</a></li>
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<li><a href="#builtins">Built-Ins</a></li>
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</ol></li>
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<li><a href="#example">Prime: A Complete Example</a></li>
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<li><a href="#internal">Internal Code Details</a>
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<ol>
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@ -44,16 +44,15 @@
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<li><a href="#tests">Test Programs</a></li>
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<li><a href="#exercise">Exercise</a></li>
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<li><a href="#todo">Things Remaining To Be Done</a></li>
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</ol>
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</li>
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</ol></li>
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</ol>
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<div class="doc_text">
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<p><b>Written by <a href="mailto:rspencer@x10sys.com">Reid Spencer</a> </b></p>
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<p> </p>
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<p><b>Written by <a href="mailto:rspencer@x10sys.com">Reid Spencer</a></b></p>
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</div>
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<hr>
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<!-- ======================================================================= -->
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<div class="doc_section"> <a name="abstract">Abstract </a></div>
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<div class="doc_section"><a name="abstract">Abstract</a></div>
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<div class="doc_text">
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<p>This document is another way to learn about LLVM. Unlike the
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<a href="LangRef.html">LLVM Reference Manual</a> or
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@ -222,11 +221,11 @@ should be constructed. In general, here's what I learned:
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before. This makes for some very clean compiler design.</li>
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</ol>
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<p>The foregoing is such an important principal, its worth making an idiom:</p>
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<pre><code>
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BasicBlock* bb = new BasicBlock();</li>
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<pre>
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BasicBlock* bb = new BasicBlock();
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bb->getInstList().push_back( new Branch( ... ) );
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new Instruction(..., bb->getTerminator() );
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</code></pre>
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</pre>
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<p>To make this clear, consider the typical if-then-else statement
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(see StackerCompiler::handle_if() method). We can set this up
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in a single function using LLVM in the following way: </p>
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@ -301,20 +300,21 @@ read the Language Reference and Programmer's Manual a couple times each, I still
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missed a few <em>very</em> key points:
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</p>
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<ul>
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<li>GetElementPtrInst gives you back a Value for the last thing indexed.</em>
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<li>All global variables in LLVM are <em>pointers</em>.
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<li>Pointers must also be dereferenced with the GetElementPtrInst instruction.
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<li>GetElementPtrInst gives you back a Value for the last thing indexed.</li>
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<li>All global variables in LLVM are <em>pointers</em>.</li>
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<li>Pointers must also be dereferenced with the GetElementPtrInst
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instruction.</li>
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</ul>
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<p>This means that when you look up an element in the global variable (assuming
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it's a struct or array), you <em>must</em> deference the pointer first! For many
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things, this leads to the idiom:
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</p>
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<pre><code>
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std::vector<Value*> index_vector;
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<pre>
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std::vector<Value*> index_vector;
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index_vector.push_back( ConstantSInt::get( Type::LongTy, 0 );
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// ... push other indices ...
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GetElementPtrInst* gep = new GetElementPtrInst( ptr, index_vector );
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</code></pre>
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</pre>
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<p>For example, suppose we have a global variable whose type is [24 x int]. The
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variable itself represents a <em>pointer</em> to that array. To subscript the
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array, we need two indices, not just one. The first index (0) dereferences the
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@ -513,10 +513,10 @@ using the following construction:</p>
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<tr class="doc_table"><td colspan="4" style="border: 2px solid blue">Definition Of Operation Of Built In Words</td></tr>
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<tr class="doc_table"><td colspan="4" style="border: 2px solid blue"><b>LOGICAL OPERATIONS</b></td></tr>
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<tr class="doc_table">
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<td style="border: 2px solid blue"><u>Word</u></td>
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<td style="border: 2px solid blue"><u>Name</u></td>
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<td style="border: 2px solid blue"><u>Operation</u></td>
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<td style="border: 2px solid blue"><u>Description</u></td>
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<td style="border: 2px solid blue">Word</td>
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<td style="border: 2px solid blue">Name</td>
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<td style="border: 2px solid blue">Operation</td>
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<td style="border: 2px solid blue">Description</td>
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</tr>
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<tr class="doc_table"><td style="border: 2px solid blue"><</td>
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<td style="border: 2px solid blue">LT</td>
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@ -576,10 +576,10 @@ using the following construction:</p>
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</tr>
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<tr><td colspan="4"><b>BITWISE OPERATORS</b></td></tr>
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<tr>
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<td style="border: 2px solid blue"><u>Word</u></td>
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<td style="border: 2px solid blue"><u>Name</u></td>
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<td style="border: 2px solid blue"><u>Operation</u></td>
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<td style="border: 2px solid blue"><u>Description</u></td>
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<td style="border: 2px solid blue">Word</td>
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<td style="border: 2px solid blue">Name</td>
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<td style="border: 2px solid blue">Operation</td>
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<td style="border: 2px solid blue">Description</td>
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</tr>
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<tr><td style="border: 2px solid blue"><<</td>
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<td style="border: 2px solid blue">SHL</td>
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@ -618,10 +618,10 @@ using the following construction:</p>
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</tr>
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<tr><td colspan="4"><b>ARITHMETIC OPERATORS</b></td></tr>
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<tr>
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<td style="border: 2px solid blue"><u>Word</u></td>
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<td style="border: 2px solid blue"><u>Name</u></td>
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<td style="border: 2px solid blue"><u>Operation</u></td>
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<td style="border: 2px solid blue"><u>Description</u></td>
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<td style="border: 2px solid blue">Word</td>
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<td style="border: 2px solid blue">Name</td>
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<td style="border: 2px solid blue">Operation</td>
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<td style="border: 2px solid blue">Description</td>
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</tr>
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<tr><td style="border: 2px solid blue">ABS</td>
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<td style="border: 2px solid blue">ABS</td>
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@ -699,10 +699,10 @@ using the following construction:</p>
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</tr>
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<tr><td colspan="4"><b>STACK MANIPULATION OPERATORS</b></td></tr>
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<tr>
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<td style="border: 2px solid blue"><u>Word</u></td>
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<td style="border: 2px solid blue"><u>Name</u></td>
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<td style="border: 2px solid blue"><u>Operation</u></td>
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<td style="border: 2px solid blue"><u>Description</u></td>
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<td style="border: 2px solid blue">Word</td>
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<td style="border: 2px solid blue">Name</td>
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<td style="border: 2px solid blue">Operation</td>
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<td style="border: 2px solid blue">Description</td>
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</tr>
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<tr><td style="border: 2px solid blue">DROP</td>
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<td style="border: 2px solid blue">DROP</td>
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@ -754,7 +754,7 @@ using the following construction:</p>
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<td style="border: 2px solid blue">The top four stack items are swapped in pairs. That is, two values
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are popped and retained. Then, two more values are popped and retained.
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The values are pushed back on to the stack in the reverse order but
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in pairs.</p>
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in pairs.</td>
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</tr>
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<tr><td style="border: 2px solid blue">OVER</td>
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<td style="border: 2px solid blue">OVER</td>
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@ -844,10 +844,10 @@ using the following construction:</p>
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</tr>
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<tr><td colspan="4"><b>MEMORY OPERATORS</b></td></tr>
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<tr>
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<td style="border: 2px solid blue"><u>Word</u></td>
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<td style="border: 2px solid blue"><u>Name</u></td>
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<td style="border: 2px solid blue"><u>Operation</u></td>
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<td style="border: 2px solid blue"><u>Description</u></td>
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<td style="border: 2px solid blue">Word</td>
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<td style="border: 2px solid blue">Name</td>
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<td style="border: 2px solid blue">Operation</td>
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<td style="border: 2px solid blue">Description</td>
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</tr>
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<tr><td style="border: 2px solid blue">MALLOC</td>
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<td style="border: 2px solid blue">MALLOC</td>
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@ -897,10 +897,10 @@ using the following construction:</p>
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</tr>
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<tr><td colspan="4"><b>CONTROL FLOW OPERATORS</b></td></tr>
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<tr>
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<td style="border: 2px solid blue"><u>Word</u></td>
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<td style="border: 2px solid blue"><u>Name</u></td>
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<td style="border: 2px solid blue"><u>Operation</u></td>
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<td style="border: 2px solid blue"><u>Description</u></td>
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<td style="border: 2px solid blue">Word</td>
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<td style="border: 2px solid blue">Name</td>
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<td style="border: 2px solid blue">Operation</td>
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<td style="border: 2px solid blue">Description</td>
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</tr>
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<tr><td style="border: 2px solid blue">RETURN</td>
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<td style="border: 2px solid blue">RETURN</td>
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@ -964,10 +964,10 @@ using the following construction:</p>
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</tr>
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<tr><td colspan="4"><b>INPUT & OUTPUT OPERATORS</b></td></tr>
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<tr>
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<td style="border: 2px solid blue"><u>Word</u></td>
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<td style="border: 2px solid blue"><u>Name</u></td>
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<td style="border: 2px solid blue"><u>Operation</u></td>
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<td style="border: 2px solid blue"><u>Description</u></td>
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<td style="border: 2px solid blue">Word</td>
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<td style="border: 2px solid blue">Name</td>
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<td style="border: 2px solid blue">Operation</td>
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<td style="border: 2px solid blue">Description</td>
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</tr>
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<tr><td style="border: 2px solid blue">SPACE</td>
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<td style="border: 2px solid blue">SPACE</td>
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@ -1311,32 +1311,32 @@ directory contains everything, as follows:</p>
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<div class="doc_subsection"><a name="lexer"></a>The Lexer</div>
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<div class="doc_text">
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<p>See projects/Stacker/lib/compiler/Lexer.l</p>
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</p></div>
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</div>
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<!-- ======================================================================= -->
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<div class="doc_subsection"><a name="parser"></a>The Parser</div>
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<div class="doc_text">
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<p>See projects/Stacker/lib/compiler/StackerParser.y</p>
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</p></div>
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</div>
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<!-- ======================================================================= -->
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<div class="doc_subsection"><a name="compiler"></a>The Compiler</div>
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<div class="doc_text">
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<p>See projects/Stacker/lib/compiler/StackerCompiler.cpp</p>
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</p></div>
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</div>
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<!-- ======================================================================= -->
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<div class="doc_subsection"><a name="runtime"></a>The Runtime</div>
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<div class="doc_text">
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<p>See projects/Stacker/lib/runtime/stacker_rt.c</p>
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</p></div>
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</div>
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<!-- ======================================================================= -->
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<div class="doc_subsection"><a name="driver"></a>Compiler Driver</div>
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<div class="doc_text">
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<p>See projects/Stacker/tools/stkrc/stkrc.cpp</p>
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</p></div>
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</div>
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<!-- ======================================================================= -->
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<div class="doc_subsection"><a name="tests"></a>Test Programs</div>
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<div class="doc_text">
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<p>See projects/Stacker/test/*.st</p>
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</p></div>
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</div>
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<!-- ======================================================================= -->
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<div class="doc_subsection"> <a name="exercise">Exercise</a></div>
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<div class="doc_text">
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@ -1390,11 +1390,20 @@ interested, here are some things that could be implemented better:</p>
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<a href="#lessons">Lessons I Learned About LLVM</a> section.</li>
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</ol>
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</div>
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<!-- ======================================================================= -->
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<!-- *********************************************************************** -->
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<hr>
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<div class="doc_footer">
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<address><a href="mailto:rspencer@x10sys.com">Reid Spencer</a></address>
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<a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a>
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<br>Last modified: $Date$ </div>
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<address>
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<a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
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<a href="http://validator.w3.org/check/referer"><img
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src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
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<a href="mailto:rspencer@x10sys.com">Reid Spencer</a><br>
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<a href="http://llvm.cs.uiuc.edu">LLVM Compiler Infrastructure</a><br>
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Last modified: $Date$
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</address>
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</body>
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</html>
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