<title>Kaleidoscope: Extending the Language: Control Flow</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="author" content="Chris Lattner">
- <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: Extending the Language: Control Flow</div>
+<h1>Kaleidoscope: Extending the Language: Control Flow</h1>
<ul>
<li><a href="index.html">Up to Tutorial Index</a></li>
</div>
<!-- *********************************************************************** -->
-<div class="doc_section"><a name="intro">Chapter 5 Introduction</a></div>
+<h2><a name="intro">Chapter 5 Introduction</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>Welcome to Chapter 5 of the "<a href="index.html">Implementing a language
with LLVM</a>" tutorial. Parts 1-4 described the implementation of the simple
</div>
<!-- *********************************************************************** -->
-<div class="doc_section"><a name="ifthen">If/Then/Else</a></div>
+<h2><a name="ifthen">If/Then/Else</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>
Extending Kaleidoscope to support if/then/else is quite straightforward. It
-basically requires adding lexer support for this "new" concept to the lexer,
+basically requires adding support for this "new" concept to the lexer,
parser, AST, and LLVM code emitter. This example is nice, because it shows how
easy it is to "grow" a language over time, incrementally extending it as new
ideas are discovered.</p>
<p>Now that we know what we "want", lets break this down into its constituent
pieces.</p>
-</div>
-
<!-- ======================================================================= -->
-<div class="doc_subsubsection"><a name="iflexer">Lexer Extensions for
-If/Then/Else</a></div>
+<h4><a name="iflexer">Lexer Extensions for If/Then/Else</a></h4>
<!-- ======================================================================= -->
-<div class="doc_text">
+<div>
<p>The lexer extensions are straightforward. First we add new enum values
for the relevant tokens:</p>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsubsection"><a name="ifast">AST Extensions for
- If/Then/Else</a></div>
+<h4><a name="ifast">AST Extensions for If/Then/Else</a></h4>
<!-- ======================================================================= -->
-<div class="doc_text">
+<div>
<p>To represent the new expression we add a new AST node for it:</p>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsubsection"><a name="ifparser">Parser Extensions for
-If/Then/Else</a></div>
+<h4><a name="ifparser">Parser Extensions for If/Then/Else</a></h4>
<!-- ======================================================================= -->
-<div class="doc_text">
+<div>
<p>Now that we have the relevant tokens coming from the lexer and we have the
AST node to build, our parsing logic is relatively straightforward. First we
</div>
<!-- ======================================================================= -->
-<div class="doc_subsubsection"><a name="ifir">LLVM IR for If/Then/Else</a></div>
+<h4><a name="ifir">LLVM IR for If/Then/Else</a></h4>
<!-- ======================================================================= -->
-<div class="doc_text">
+<div>
<p>Now that we have it parsing and building the AST, the final piece is adding
LLVM code generation support. This is the most interesting part of the
define double @baz(double %x) {
entry:
- %ifcond = fcmp one double %x, 0.000000e+00
- br i1 %ifcond, label %then, label %else
+ %ifcond = fcmp one double %x, 0.000000e+00
+ br i1 %ifcond, label %then, label %else
then: ; preds = %entry
- %calltmp = call double @foo()
- br label %ifcont
+ %calltmp = call double @foo()
+ br label %ifcont
else: ; preds = %entry
- %calltmp1 = call double @bar()
- br label %ifcont
+ %calltmp1 = call double @bar()
+ br label %ifcont
ifcont: ; preds = %else, %then
- %iftmp = phi double [ %calltmp, %then ], [ %calltmp1, %else ]
- ret double %iftmp
+ %iftmp = phi double [ %calltmp, %then ], [ %calltmp1, %else ]
+ ret double %iftmp
}
</pre>
</div>
href="../ProgrammersManual.html#ViewGraph">a window will pop up</a> and you'll
see this graph:</p>
-<
center><img src="LangImpl5-cfg.png" alt="Example CFG" width="423"
-height="315"></center>
+<
div style="text-align: center"><img src="LangImpl5-cfg.png" alt="Example CFG" width="423"
+height="315"></div>
<p>Another way to get this is to call "<tt>F->viewCFG()</tt>" or
"<tt>F->viewCFGOnly()</tt>" (where F is a "<tt>Function*</tt>") either by
</div>
<!-- ======================================================================= -->
-<div class="doc_subsubsection"><a name="ifcodegen">Code Generation for
-If/Then/Else</a></div>
+<h4><a name="ifcodegen">Code Generation for If/Then/Else</a></h4>
<!-- ======================================================================= -->
-<div class="doc_text">
+<div>
<p>In order to generate code for this, we implement the <tt>Codegen</tt> method
for <tt>IfExprAST</tt>:</p>
// Convert condition to a bool by comparing equal to 0.0.
CondV = Builder.CreateFCmpONE(CondV,
- ConstantFP::get(APFloat(0.0)),
+ ConstantFP::get(getGlobalContext(), APFloat(0.0)),
"ifcond");
</pre>
</div>
// Create blocks for the then and else cases. Insert the 'then' block at the
// end of the function.
- BasicBlock *ThenBB = BasicBlock::Create("then", TheFunction);
- BasicBlock *ElseBB = BasicBlock::Create("else");
- BasicBlock *MergeBB = BasicBlock::Create("ifcont");
+ BasicBlock *ThenBB = BasicBlock::Create(getGlobalContext(), "then", TheFunction);
+ BasicBlock *ElseBB = BasicBlock::Create(getGlobalContext(), "else");
+ BasicBlock *MergeBB = BasicBlock::Create(getGlobalContext(), "ifcont");
Builder.CreateCondBr(CondV, ThenBB, ElseBB);
</pre>
// Emit merge block.
TheFunction->getBasicBlockList().push_back(MergeBB);
Builder.SetInsertPoint(MergeBB);
- PHINode *PN = Builder.CreatePHI(Type::DoubleTy, "iftmp");
+ PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()), 2,
+ "iftmp");
PN->addIncoming(ThenV, ThenBB);
PN->addIncoming(ElseV, ElseBB);
</div>
+</div>
+
<!-- *********************************************************************** -->
-<div class="doc_section"><a name="for">'for' Loop Expression</a></div>
+<h2><a name="for">'for' Loop Expression</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>Now that we know how to add basic control flow constructs to the language,
we have the tools to add more powerful things. Lets add something more
<p>As before, lets talk about the changes that we need to Kaleidoscope to
support this.</p>
-</div>
-
<!-- ======================================================================= -->
-<div class="doc_subsubsection"><a name="forlexer">Lexer Extensions for
-the 'for' Loop</a></div>
+<h4><a name="forlexer">Lexer Extensions for the 'for' Loop</a></h4>
<!-- ======================================================================= -->
-<div class="doc_text">
+<div>
<p>The lexer extensions are the same sort of thing as for if/then/else:</p>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsubsection"><a name="forast">AST Extensions for
-the 'for' Loop</a></div>
+<h4><a name="forast">AST Extensions for the 'for' Loop</a></h4>
<!-- ======================================================================= -->
-<div class="doc_text">
+<div>
<p>The AST node is just as simple. It basically boils down to capturing
the variable name and the constituent expressions in the node.</p>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsubsection"><a name="forparser">Parser Extensions for
-the 'for' Loop</a></div>
+<h4><a name="forparser">Parser Extensions for the 'for' Loop</a></h4>
<!-- ======================================================================= -->
-<div class="doc_text">
+<div>
<p>The parser code is also fairly standard. The only interesting thing here is
handling of the optional step value. The parser code handles it by checking to
</div>
<!-- ======================================================================= -->
-<div class="doc_subsubsection"><a name="forir">LLVM IR for
-the 'for' Loop</a></div>
+<h4><a name="forir">LLVM IR for the 'for' Loop</a></h4>
<!-- ======================================================================= -->
-<div class="doc_text">
+<div>
<p>Now we get to the good part: the LLVM IR we want to generate for this thing.
With the simple example above, we get this LLVM IR (note that this dump is
define double @printstar(double %n) {
entry:
- ; initial value = 1.0 (inlined into phi)
- br label %loop
+ ; initial value = 1.0 (inlined into phi)
+ br label %loop
loop: ; preds = %loop, %entry
- %i = phi double [ 1.000000e+00, %entry ], [ %nextvar, %loop ]
- ; body
- %calltmp = call double @putchard( double 4.200000e+01 )
- ; increment
- %nextvar = add double %i, 1.000000e+00
-
- ; termination test
- %cmptmp = fcmp ult double %i, %n
- %booltmp = uitofp i1 %cmptmp to double
- %loopcond = fcmp one double %booltmp, 0.000000e+00
- br i1 %loopcond, label %loop, label %afterloop
+ %i = phi double [ 1.000000e+00, %entry ], [ %nextvar, %loop ]
+ ; body
+ %calltmp = call double @putchard(double 4.200000e+01)
+ ; increment
+ %nextvar = fadd double %i, 1.000000e+00
+
+ ; termination test
+ %cmptmp = fcmp ult double %i, %n
+ %booltmp = uitofp i1 %cmptmp to double
+ %loopcond = fcmp one double %booltmp, 0.000000e+00
+ br i1 %loopcond, label %loop, label %afterloop
afterloop: ; preds = %loop
- ; loop always returns 0.0
- ret double 0.000000e+00
+ ; loop always returns 0.0
+ ret double 0.000000e+00
}
</pre>
</div>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsubsection"><a name="forcodegen">Code Generation for
-the 'for' Loop</a></div>
+<h4><a name="forcodegen">Code Generation for the 'for' Loop</a></h4>
<!-- ======================================================================= -->
-<div class="doc_text">
+<div>
<p>The first part of Codegen is very simple: we just output the start expression
for the loop value:</p>
// block.
Function *TheFunction = Builder.GetInsertBlock()->getParent();
BasicBlock *PreheaderBB = Builder.GetInsertBlock();
- BasicBlock *LoopBB = BasicBlock::Create("loop", TheFunction);
+ BasicBlock *LoopBB = BasicBlock::Create(getGlobalContext(), "loop", TheFunction);
// Insert an explicit fall through from the current block to the LoopBB.
Builder.CreateBr(LoopBB);
Builder.SetInsertPoint(LoopBB);
// Start the PHI node with an entry for Start.
- PHINode *Variable = Builder.CreatePHI(Type::DoubleTy, VarName.c_str());
+ PHINode *Variable = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()), 2, VarName.c_str());
Variable->addIncoming(StartVal, PreheaderBB);
</pre>
</div>
if (StepVal == 0) return 0;
} else {
// If not specified, use 1.0.
- StepVal = ConstantFP::get(APFloat(1.0));
+ StepVal = ConstantFP::get(getGlobalContext(), APFloat(1.0));
}
- Value *NextVar = Builder.CreateAdd(Variable, StepVal, "nextvar");
+ Value *NextVar = Builder.CreateFAdd(Variable, StepVal, "nextvar");
</pre>
</div>
// Convert condition to a bool by comparing equal to 0.0.
EndCond = Builder.CreateFCmpONE(EndCond,
- ConstantFP::get(APFloat(0.0)),
+ ConstantFP::get(getGlobalContext(), APFloat(0.0)),
"loopcond");
</pre>
</div>
<pre>
// Create the "after loop" block and insert it.
BasicBlock *LoopEndBB = Builder.GetInsertBlock();
- BasicBlock *AfterBB = BasicBlock::Create("afterloop", TheFunction);
+ BasicBlock *AfterBB = BasicBlock::Create(getGlobalContext(), "afterloop", TheFunction);
// Insert the conditional branch into the end of LoopEndBB.
Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
</div>
<p>With the code for the body of the loop complete, we just need to finish up
-the control flow for it. This code remembers the end block (for the phi node), then creates the block for the loop exit ("afterloop"). Based on the value of the
-exit condition, it creates a conditional branch that chooses between executing
-the loop again and exiting the loop. Any future code is emitted in the
-"afterloop" block, so it sets the insertion position to it.</p>
+the control flow for it. This code remembers the end block (for the phi node),
+then creates the block for the loop exit ("afterloop"). Based on the value of
+the exit condition, it creates a conditional branch that chooses between
+executing the loop again and exiting the loop. Any future code is emitted in
+the "afterloop" block, so it sets the insertion position to it.</p>
<div class="doc_code">
<pre>
NamedValues.erase(VarName);
// for expr always returns 0.0.
- return TheFunction->getContext()->getNullValue(Type::DoubleTy);
+ return Constant::getNullValue(Type::getDoubleTy(getGlobalContext()));
}
</pre>
</div>
</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 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/JIT.h"
+#include "llvm/IRBuilder.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
-#include "llvm/ModuleProvider.h"
#include "llvm/PassManager.h"
#include "llvm/Analysis/Verifier.h"
-#include "llvm/Target/TargetData.h"
+#include "llvm/Analysis/Passes.h"
+#include "llvm/DataLayout.h"
#include "llvm/Transforms/Scalar.h"
-#include "llvm/Support/IRBuilder.h"
+#include "llvm/Support/TargetSelect.h"
#include <cstdio>
#include <string>
#include <map>
};
/// PrototypeAST - This class represents the "prototype" for a function,
-/// which captures its argument names as well as if it is an operator.
+/// which captures its name, and its argument names (thus implicitly the number
+/// of arguments the function takes).
class PrototypeAST {
std::string Name;
std::vector<std::string> Args;
//===----------------------------------------------------------------------===//
/// CurTok/getNextToken - Provide a simple token buffer. CurTok is the current
-/// token the parser it looking at. getNextToken reads another token from the
+/// token the parser is looking at. getNextToken reads another token from the
/// lexer and updates CurTok with its results.
static int CurTok;
static int getNextToken() {
ExprAST *Arg = ParseExpression();
if (!Arg) return 0;
Args.push_back(Arg);
-
+
if (CurTok == ')') break;
-
+
if (CurTok != ',')
return Error("Expected ')' or ',' in argument list");
getNextToken();
return new ForExprAST(IdName, Start, End, Step, Body);
}
-
/// primary
/// ::= identifierexpr
/// ::= numberexpr
Value *ErrorV(const char *Str) { Error(Str); return 0; }
Value *NumberExprAST::Codegen() {
- return ConstantFP::get(APFloat(Val));
+ return ConstantFP::get(getGlobalContext(), APFloat(Val));
}
Value *VariableExprAST::Codegen() {
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
- return Builder.CreateUIToFP(L, Type::DoubleTy, "booltmp");
+ return Builder.CreateUIToFP(L, Type::getDoubleTy(getGlobalContext()),
+ "booltmp");
default: return ErrorV("invalid binary operator");
}
}
if (ArgsV.back() == 0) return 0;
}
- return Builder.CreateCall(CalleeF, ArgsV.begin(), ArgsV.end(), "calltmp");
+ return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
}
Value *IfExprAST::Codegen() {
// Convert condition to a bool by comparing equal to 0.0.
CondV = Builder.CreateFCmpONE(CondV,
- ConstantFP::get(APFloat(0.0)),
+ ConstantFP::get(getGlobalContext(), APFloat(0.0)),
"ifcond");
Function *TheFunction = Builder.GetInsertBlock()->getParent();
// Create blocks for the then and else cases. Insert the 'then' block at the
// end of the function.
- BasicBlock *ThenBB = BasicBlock::Create("then", TheFunction);
- BasicBlock *ElseBB = BasicBlock::Create("else");
- BasicBlock *MergeBB = BasicBlock::Create("ifcont");
+ BasicBlock *ThenBB = BasicBlock::Create(getGlobalContext(), "then", TheFunction);
+ BasicBlock *ElseBB = BasicBlock::Create(getGlobalContext(), "else");
+ BasicBlock *MergeBB = BasicBlock::Create(getGlobalContext(), "ifcont");
Builder.CreateCondBr(CondV, ThenBB, ElseBB);
// Emit merge block.
TheFunction->getBasicBlockList().push_back(MergeBB);
Builder.SetInsertPoint(MergeBB);
- PHINode *PN = Builder.CreatePHI(Type::DoubleTy, "iftmp");
+ PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()), 2,
+ "iftmp");
PN->addIncoming(ThenV, ThenBB);
PN->addIncoming(ElseV, ElseBB);
// block.
Function *TheFunction = Builder.GetInsertBlock()->getParent();
BasicBlock *PreheaderBB = Builder.GetInsertBlock();
- BasicBlock *LoopBB = BasicBlock::Create("loop", TheFunction);
+ BasicBlock *LoopBB = BasicBlock::Create(getGlobalContext(), "loop", TheFunction);
// Insert an explicit fall through from the current block to the LoopBB.
Builder.CreateBr(LoopBB);
Builder.SetInsertPoint(LoopBB);
// Start the PHI node with an entry for Start.
- PHINode *Variable = Builder.CreatePHI(Type::DoubleTy, VarName.c_str());
+ PHINode *Variable = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()), 2, VarName.c_str());
Variable->addIncoming(StartVal, PreheaderBB);
// Within the loop, the variable is defined equal to the PHI node. If it
if (StepVal == 0) return 0;
} else {
// If not specified, use 1.0.
- StepVal = ConstantFP::get(APFloat(1.0));
+ StepVal = ConstantFP::get(getGlobalContext(), APFloat(1.0));
}
- Value *NextVar = Builder.CreateAdd(Variable, StepVal, "nextvar");
+ Value *NextVar = Builder.CreateFAdd(Variable, StepVal, "nextvar");
// Compute the end condition.
Value *EndCond = End->Codegen();
// Convert condition to a bool by comparing equal to 0.0.
EndCond = Builder.CreateFCmpONE(EndCond,
- ConstantFP::get(APFloat(0.0)),
+ ConstantFP::get(getGlobalContext(), APFloat(0.0)),
"loopcond");
// Create the "after loop" block and insert it.
BasicBlock *LoopEndBB = Builder.GetInsertBlock();
- BasicBlock *AfterBB = BasicBlock::Create("afterloop", TheFunction);
+ BasicBlock *AfterBB = BasicBlock::Create(getGlobalContext(), "afterloop", TheFunction);
// Insert the conditional branch into the end of LoopEndBB.
Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
// for expr always returns 0.0.
- return Constant::getNullValue(Type::DoubleTy);
+ return Constant::getNullValue(Type::getDoubleTy(getGlobalContext()));
}
Function *PrototypeAST::Codegen() {
// Make the function type: double(double,double) etc.
- std::vector<const Type*> Doubles(Args.size(), Type::DoubleTy);
- FunctionType *FT = FunctionType::get(Type::DoubleTy, Doubles, false);
+ std::vector<Type*> Doubles(Args.size(),
+ Type::getDoubleTy(getGlobalContext()));
+ FunctionType *FT = FunctionType::get(Type::getDoubleTy(getGlobalContext()),
+ Doubles, false);
Function *F = Function::Create(FT, Function::ExternalLinkage, Name, TheModule);
return 0;
// Create a new basic block to start insertion into.
- BasicBlock *BB = BasicBlock::Create("entry", TheFunction);
+ BasicBlock *BB = BasicBlock::Create(getGlobalContext(), "entry", TheFunction);
Builder.SetInsertPoint(BB);
if (Value *RetVal = Body->Codegen()) {
}
static void HandleTopLevelExpression() {
- // Evaluate a top level expression into an anonymous function.
+ // Evaluate a top-level expression into an anonymous function.
if (FunctionAST *F = ParseTopLevelExpr()) {
if (Function *LF = F->Codegen()) {
// JIT the function, returning a function pointer.
// Cast it to the right type (takes no arguments, returns a double) so we
// can call it as a native function.
- double (*FP)() = (double (*)())FPtr;
+ double (*FP)() = (double (*)())(intptr_t)FPtr;
fprintf(stderr, "Evaluated to %f\n", FP());
}
} else {
fprintf(stderr, "ready> ");
switch (CurTok) {
case tok_eof: return;
- case ';': getNextToken(); break; // ignore top level semicolons.
+ case ';': getNextToken(); break; // ignore top-level semicolons.
case tok_def: HandleDefinition(); break;
case tok_extern: HandleExtern(); break;
default: HandleTopLevelExpression(); break;
}
}
-
-
//===----------------------------------------------------------------------===//
// "Library" functions that can be "extern'd" from user code.
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
int main() {
+ InitializeNativeTarget();
+ LLVMContext &Context = getGlobalContext();
+
// Install standard binary operators.
// 1 is lowest precedence.
BinopPrecedence['<'] = 10;
getNextToken();
// Make the module, which holds all the code.
- TheModule = new Module("my cool jit", getGlobalContext());
-
- // Create the JIT.
- TheExecutionEngine = ExecutionEngine::create(TheModule);
+ TheModule = new Module("my cool jit", Context);
+
+ // Create the JIT. This takes ownership of the module.
+ std::string ErrStr;
+ TheExecutionEngine = EngineBuilder(TheModule).setErrorStr(&ErrStr).create();
+ if (!TheExecutionEngine) {
+ fprintf(stderr, "Could not create ExecutionEngine: %s\n", ErrStr.c_str());
+ exit(1);
+ }
- {
- ExistingModuleProvider OurModuleProvider(TheModule);
- FunctionPassManager OurFPM(&OurModuleProvider);
-
- // Set up the optimizer pipeline. Start with registering info about how the
- // target lays out data structures.
- OurFPM.add(new TargetData(*TheExecutionEngine->getTargetData()));
- // Do simple "peephole" optimizations and bit-twiddling optzns.
- OurFPM.add(createInstructionCombiningPass());
- // Reassociate expressions.
- OurFPM.add(createReassociatePass());
- // Eliminate Common SubExpressions.
- OurFPM.add(createGVNPass());
- // Simplify the control flow graph (deleting unreachable blocks, etc).
- OurFPM.add(createCFGSimplificationPass());
- // Set the global so the code gen can use this.
- TheFPM = &OurFPM;
-
- // Run the main "interpreter loop" now.
- MainLoop();
-
- TheFPM = 0;
+ FunctionPassManager OurFPM(TheModule);
+
+ // Set up the optimizer pipeline. Start with registering info about how the
+ // target lays out data structures.
+ OurFPM.add(new DataLayout(*TheExecutionEngine->getDataLayout()));
+ // Provide basic AliasAnalysis support for GVN.
+ OurFPM.add(createBasicAliasAnalysisPass());
+ // Do simple "peephole" optimizations and bit-twiddling optzns.
+ OurFPM.add(createInstructionCombiningPass());
+ // Reassociate expressions.
+ OurFPM.add(createReassociatePass());
+ // Eliminate Common SubExpressions.
+ OurFPM.add(createGVNPass());
+ // Simplify the control flow graph (deleting unreachable blocks, etc).
+ OurFPM.add(createCFGSimplificationPass());
+
+ OurFPM.doInitialization();
+
+ // Set the global so the code gen can use this.
+ TheFPM = &OurFPM;
+
+ // Run the main "interpreter loop" now.
+ MainLoop();
+
+ TheFPM = 0;
+
+ // Print out all of the generated code.
+ TheModule->dump();
- // Print out all of the generated code.
- TheModule->dump();
- } // Free module provider (and thus the module) and pass manager.
-
return 0;
}
</pre>
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: $Date$
</address>
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