<title>Kaleidoscope: Adding JIT and Optimizer Support</title>
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+ <link rel="stylesheet" href="../_static/llvm.css" type="text/css">
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-<div class="doc_title">Kaleidoscope: Adding JIT and Optimizer Support</div>
+<h1>Kaleidoscope: Adding JIT and Optimizer Support</h1>
<ul>
<li><a href="index.html">Up to Tutorial Index</a></li>
</div>
<!-- *********************************************************************** -->
-<div class="doc_section"><a name="intro">Chapter 4 Introduction</a></div>
+<h2><a name="intro">Chapter 4 Introduction</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>Welcome to Chapter 4 of the "<a href="index.html">Implementing a language
with LLVM</a>" tutorial. Chapters 1-3 described the implementation of a simple
</div>
<!-- *********************************************************************** -->
-<div class="doc_section"><a name="trivialconstfold">Trivial Constant
-Folding</a></div>
+<h2><a name="trivialconstfold">Trivial Constant Folding</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>
Our demonstration for Chapter 3 is elegant and easy to extend. Unfortunately,
Read function definition:
define double @test(double %x) {
entry:
- %addtmp = add double 3.000000e+00, %x
+ %addtmp = fadd double 3.000000e+00, %x
ret double %addtmp
}
</pre>
Read function definition:
define double @test(double %x) {
entry:
- %addtmp = add double 2.000000e+00, 1.000000e+00
- %addtmp1 = add double %addtmp, %x
+ %addtmp = fadd double 2.000000e+00, 1.000000e+00
+ %addtmp1 = fadd double %addtmp, %x
ret double %addtmp1
}
</pre>
ready> Read function definition:
define double @test(double %x) {
entry:
- %addtmp = add double 3.000000e+00, %x
- %addtmp1 = add double %x, 3.000000e+00
- %multmp = mul double %addtmp, %addtmp1
+ %addtmp = fadd double 3.000000e+00, %x
+ %addtmp1 = fadd double %x, 3.000000e+00
+ %multmp = fmul double %addtmp, %addtmp1
ret double %multmp
}
</pre>
</div>
<!-- *********************************************************************** -->
-<div class="doc_section"><a name="optimizerpasses">LLVM Optimization
- Passes</a></div>
+<h2><a name="optimizerpasses">LLVM Optimization Passes</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>LLVM provides many optimization passes, which do many different sorts of
things and have different tradeoffs. Unlike other systems, LLVM doesn't hold
// 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());
// Do simple "peephole" optimizations and bit-twiddling optzns.
OurFPM.add(createInstructionCombiningPass());
// Reassociate expressions.
ready> Read function definition:
define double @test(double %x) {
entry:
- %addtmp = add double %x, 3.000000e+00
- %multmp = mul double %addtmp, %addtmp
+ %addtmp = fadd double %x, 3.000000e+00
+ %multmp = fmul double %addtmp, %addtmp
ret double %multmp
}
</pre>
<p>LLVM provides a wide variety of optimizations that can be used in certain
circumstances. Some <a href="../Passes.html">documentation about the various
passes</a> is available, but it isn't very complete. Another good source of
-ideas can come from looking at the passes that <tt>llvm-gcc</tt> or
-<tt>llvm-ld</tt> run to get started. The "<tt>opt</tt>" tool allows you to
-experiment with passes from the command line, so you can see if they do
-anything.</p>
+ideas can come from looking at the passes that <tt>Clang</tt> runs to get
+started. The "<tt>opt</tt>" tool allows you to experiment with passes from the
+command line, so you can see if they do anything.</p>
<p>Now that we have reasonable code coming out of our front-end, lets talk about
executing it!</p>
</div>
<!-- *********************************************************************** -->
-<div class="doc_section"><a name="jit">Adding a JIT Compiler</a></div>
+<h2><a name="jit">Adding a JIT Compiler</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>Code that is available in LLVM IR can have a wide variety of tools
applied to it. For example, you can run optimizations on it (as we did above),
<div class="doc_code">
<pre>
ready> <b>4+5;</b>
-define double @""() {
+Read top-level expression:
+define double @0() {
entry:
- ret double 9.000000e+00
+ ret double 9.000000e+00
}
<em>Evaluated to 9.000000</em>
Read function definition:
define double @testfunc(double %x, double %y) {
entry:
- %multmp = mul double %y, 2.000000e+00
- %addtmp = add double %multmp, %x
- ret double %addtmp
+ %multmp = fmul double %y, 2.000000e+00
+ %addtmp = fadd double %multmp, %x
+ ret double %addtmp
}
ready> <b>testfunc(4, 10);</b>
-define double @""() {
+Read top-level expression:
+define double @1() {
entry:
- %calltmp = call double @testfunc( double 4.000000e+00, double 1.000000e+01 )
- ret double %calltmp
+ %calltmp = call double @testfunc(double 4.000000e+00, double 1.000000e+01)
+ ret double %calltmp
}
<em>Evaluated to 24.000000</em>
declare double @cos(double)
ready> <b>sin(1.0);</b>
+Read top-level expression:
+define double @2() {
+entry:
+ ret double 0x3FEAED548F090CEE
+}
+
<em>Evaluated to 0.841471</em>
ready> <b>def foo(x) sin(x)*sin(x) + cos(x)*cos(x);</b>
Read function definition:
define double @foo(double %x) {
entry:
- %calltmp = call double @sin( double %x )
- %multmp = mul double %calltmp, %calltmp
- %calltmp2 = call double @cos( double %x )
- %multmp4 = mul double %calltmp2, %calltmp2
- %addtmp = add double %multmp, %multmp4
- ret double %addtmp
+ %calltmp = call double @sin(double %x)
+ %multmp = fmul double %calltmp, %calltmp
+ %calltmp2 = call double @cos(double %x)
+ %multmp4 = fmul double %calltmp2, %calltmp2
+ %addtmp = fadd double %multmp, %multmp4
+ ret double %addtmp
}
ready> <b>foo(4.0);</b>
+Read top-level expression:
+define double @3() {
+entry:
+ %calltmp = call double @foo(double 4.000000e+00)
+ ret double %calltmp
+}
+
<em>Evaluated to 1.000000</em>
</pre>
</div>
</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
<div class="doc_code">
<pre>
- # Compile
- g++ -g toy.cpp `llvm-config --cppflags --ldflags --libs core jit interpreter native` -O3 -o toy
- # Run
- ./toy
+# Compile
+clang++ -g toy.cpp `llvm-config --cppflags --ldflags --libs core jit native` -O3 -o toy
+# Run
+./toy
</pre>
</div>
<pre>
#include "llvm/DerivedTypes.h"
#include "llvm/ExecutionEngine/ExecutionEngine.h"
-#include "llvm/ExecutionEngine/Interpreter.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/Target/TargetData.h"
-#include "llvm/Target/TargetSelect.h"
#include "llvm/Transforms/Scalar.h"
-#include "llvm/Support/IRBuilder.h"
+#include "llvm/Support/TargetSelect.h"
#include <cstdio>
#include <string>
#include <map>
if (L == 0 || R == 0) return 0;
switch (Op) {
- case '+': return Builder.CreateAdd(L, R, "addtmp");
- case '-': return Builder.CreateSub(L, R, "subtmp");
- case '*': return Builder.CreateMul(L, R, "multmp");
+ 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
if (ArgsV.back() == 0) return 0;
}
- return Builder.CreateCall(CalleeF, ArgsV.begin(), ArgsV.end(), "calltmp");
+ return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
}
Function *PrototypeAST::Codegen() {
// Make the function type: double(double,double) etc.
- std::vector<const Type*> Doubles(Args.size(),
- Type::getDoubleTy(getGlobalContext()));
+ std::vector<Type*> Doubles(Args.size(),
+ Type::getDoubleTy(getGlobalContext()));
FunctionType *FT = FunctionType::get(Type::getDoubleTy(getGlobalContext()),
Doubles, false);
// Evaluate a top-level expression into an anonymous function.
if (FunctionAST *F = ParseTopLevelExpr()) {
if (Function *LF = F->Codegen()) {
+ fprintf(stderr, "Read top-level expression:");
+ LF->dump();
+
// JIT the function, returning a function pointer.
void *FPtr = TheExecutionEngine->getPointerToFunction(LF);
TheModule = new Module("my cool jit", Context);
// Create the JIT. This takes ownership of the module.
- TheExecutionEngine = EngineBuilder(TheModule).create();
+ std::string ErrStr;
+ TheExecutionEngine = EngineBuilder(TheModule).setErrorStr(&ErrStr).create();
+ if (!TheExecutionEngine) {
+ fprintf(stderr, "Could not create ExecutionEngine: %s\n", ErrStr.c_str());
+ exit(1);
+ }
FunctionPassManager OurFPM(TheModule);
// 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());
// Do simple "peephole" optimizations and bit-twiddling optzns.
OurFPM.add(createInstructionCombiningPass());
// Reassociate expressions.
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>
- 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: $Date$
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