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-<div class="doc_title">Kaleidoscope: Extending the Language: Mutable Variables</div>
+<h1>Kaleidoscope: Extending the Language: Mutable Variables</h1>
<ul>
<li><a href="index.html">Up to Tutorial Index</a></li>
</div>
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-<div class="doc_section"><a name="intro">Chapter 7 Introduction</a></div>
+<h2><a name="intro">Chapter 7 Introduction</a></h2>
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-<div class="doc_text">
+<div>
<p>Welcome to Chapter 7 of the "<a href="index.html">Implementing a language
with LLVM</a>" tutorial. In chapters 1 through 6, we've built a very
</div>
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-<div class="doc_section"><a name="why">Why is this a hard problem?</a></div>
+<h2><a name="why">Why is this a hard problem?</a></h2>
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-<div class="doc_text">
+<div>
<p>
To understand why mutable variables cause complexities in SSA construction,
</div>
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-<div class="doc_section"><a name="memory">Memory in LLVM</a></div>
+<h2><a name="memory">Memory in LLVM</a></h2>
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-<div class="doc_text">
+<div>
<p>The 'trick' here is that while LLVM does require all register values to be
in SSA form, it does not require (or permit) memory objects to be in SSA form.
</div>
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-<div class="doc_section"><a name="kalvars">Mutable Variables in
-Kaleidoscope</a></div>
+<h2><a name="kalvars">Mutable Variables in Kaleidoscope</a></h2>
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-<div class="doc_text">
+<div>
<p>Now that we know the sort of problem we want to tackle, lets see what this
looks like in the context of our little Kaleidoscope language. We're going to
</div>
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-<div class="doc_section"><a name="adjustments">Adjusting Existing Variables for
-Mutation</a></div>
+<h2><a name="adjustments">Adjusting Existing Variables for Mutation</a></h2>
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-<div class="doc_text">
+<div>
<p>
The symbol table in Kaleidoscope is managed at code generation time by the
</div>
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-<div class="doc_section"><a name="assignment">New Assignment Operator</a></div>
+<h2><a name="assignment">New Assignment Operator</a></h2>
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-<div class="doc_text">
+<div>
<p>With our current framework, adding a new assignment operator is really
simple. We will parse it just like any other binary operator, but handle it
</div>
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-<div class="doc_section"><a name="localvars">User-defined Local
-Variables</a></div>
+<h2><a name="localvars">User-defined Local Variables</a></h2>
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-<div class="doc_text">
+<div>
<p>Adding var/in is just like any other other extensions we made to
Kaleidoscope: we extend the lexer, the parser, the AST and the code generator.
</div>
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-<div class="doc_section"><a name="code">Full Code Listing</a></div>
+<h2><a name="code">Full Code Listing</a></h2>
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-<div class="doc_text">
+<div>
<p>
Here is the complete code listing for our running example, enhanced with mutable
#include "llvm/Module.h"
#include "llvm/PassManager.h"
#include "llvm/Analysis/Verifier.h"
+#include "llvm/Analysis/Passes.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetSelect.h"
#include "llvm/Transforms/Scalar.h"
// Emit merge block.
TheFunction->getBasicBlockList().push_back(MergeBB);
Builder.SetInsertPoint(MergeBB);
- PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()),
+ PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()), 2,
"iftmp");
PN->addIncoming(ThenV, ThenBB);
// Set up the optimizer pipeline. Start with registering info about how the
// target lays out data structures.
OurFPM.add(new TargetData(*TheExecutionEngine->getTargetData()));
+ // Provide basic AliasAnalysis support for GVN.
+ OurFPM.add(createBasicAliasAnalysisPass());
// Promote allocas to registers.
OurFPM.add(createPromoteMemoryToRegisterPass());
// Do simple "peephole" optimizations and bit-twiddling optzns.
src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
<a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
- <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
+ <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Last modified: $Date$
</address>
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