<body>
-<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>
<!-- *********************************************************************** -->
-<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>
<!-- *********************************************************************** -->
-<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>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<p>
The symbol table in Kaleidoscope is managed at code generation time by the
<b>// Reload, increment, and restore the alloca. This handles the case where
// the body of the loop mutates the variable.
Value *CurVar = Builder.CreateLoad(Alloca);
- Value *NextVar = Builder.CreateAdd(CurVar, StepVal, "nextvar");
+ Value *NextVar = Builder.CreateFAdd(CurVar, StepVal, "nextvar");
Builder.CreateStore(NextVar, Alloca);</b>
...
</pre>
else: ; preds = %entry
<b>%x3 = load double* %x1</b>
- %subtmp = sub double %x3, 1.000000e+00
- %calltmp = call double @fib( double %subtmp )
+ %subtmp = fsub double %x3, 1.000000e+00
+ %calltmp = call double @fib(double %subtmp)
<b>%x4 = load double* %x1</b>
- %subtmp5 = sub double %x4, 2.000000e+00
- %calltmp6 = call double @fib( double %subtmp5 )
- %addtmp = add double %calltmp, %calltmp6
+ %subtmp5 = fsub double %x4, 2.000000e+00
+ %calltmp6 = call double @fib(double %subtmp5)
+ %addtmp = fadd double %calltmp, %calltmp6
br label %ifcont
ifcont: ; preds = %else, %then
br label %ifcont
else:
- %subtmp = sub double <b>%x</b>, 1.000000e+00
- %calltmp = call double @fib( double %subtmp )
- %subtmp5 = sub double <b>%x</b>, 2.000000e+00
- %calltmp6 = call double @fib( double %subtmp5 )
- %addtmp = add double %calltmp, %calltmp6
+ %subtmp = fsub double <b>%x</b>, 1.000000e+00
+ %calltmp = call double @fib(double %subtmp)
+ %subtmp5 = fsub double <b>%x</b>, 2.000000e+00
+ %calltmp6 = call double @fib(double %subtmp5)
+ %addtmp = fadd double %calltmp, %calltmp6
br label %ifcont
ifcont: ; preds = %else, %then
br i1 %ifcond, label %else, label %ifcont
else:
- %subtmp = sub double %x, 1.000000e+00
- %calltmp = call double @fib( double %subtmp )
- %subtmp5 = sub double %x, 2.000000e+00
- %calltmp6 = call double @fib( double %subtmp5 )
- %addtmp = add double %calltmp, %calltmp6
+ %subtmp = fsub double %x, 1.000000e+00
+ %calltmp = call double @fib(double %subtmp)
+ %subtmp5 = fsub double %x, 2.000000e+00
+ %calltmp6 = call double @fib(double %subtmp5)
+ %addtmp = fadd double %calltmp, %calltmp6
ret double %addtmp
ifcont:
</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>
<!-- *********************************************************************** -->
-<div class="doc_section"><a name="localvars">User-defined Local
-Variables</a></div>
+<h2><a name="localvars">User-defined Local Variables</a></h2>
<!-- *********************************************************************** -->
-<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>
<!-- *********************************************************************** -->
-<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 mutable
<pre>
#include "llvm/DerivedTypes.h"
#include "llvm/ExecutionEngine/ExecutionEngine.h"
-#include "llvm/ExecutionEngine/Interpreter.h"
#include "llvm/ExecutionEngine/JIT.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
-#include "llvm/ModuleProvider.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"
};
/// 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), as well as if it is an operator.
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 VarExprAST(VarNames, Body);
}
-
/// primary
/// ::= identifierexpr
/// ::= numberexpr
static PrototypeAST *ParsePrototype() {
std::string FnName;
- int Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
+ unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
unsigned BinaryPrecedence = 30;
switch (CurTok) {
const std::string &VarName) {
IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
TheFunction->getEntryBlock().begin());
- return TmpB.CreateAlloca(Type::getDoubleTy(getGlobalContext()), 0, VarName.c_str());
+ return TmpB.CreateAlloca(Type::getDoubleTy(getGlobalContext()), 0,
+ VarName.c_str());
}
-
Value *NumberExprAST::Codegen() {
return ConstantFP::get(getGlobalContext(), APFloat(Val));
}
return Builder.CreateCall(F, OperandV, "unop");
}
-
Value *BinaryExprAST::Codegen() {
// Special case '=' because we don't want to emit the LHS as an expression.
if (Op == '=') {
return Val;
}
-
Value *L = LHS->Codegen();
Value *R = RHS->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
// 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);
// Make the new basic block for the loop header, inserting after current
// block.
- BasicBlock *PreheaderBB = Builder.GetInsertBlock();
BasicBlock *LoopBB = BasicBlock::Create(getGlobalContext(), "loop", TheFunction);
// Insert an explicit fall through from the current block to the LoopBB.
// Reload, increment, and restore the alloca. This handles the case where
// the body of the loop mutates the variable.
Value *CurVar = Builder.CreateLoad(Alloca, VarName.c_str());
- Value *NextVar = Builder.CreateAdd(CurVar, StepVal, "nextvar");
+ Value *NextVar = Builder.CreateFAdd(CurVar, StepVal, "nextvar");
Builder.CreateStore(NextVar, Alloca);
// Convert condition to a bool by comparing equal to 0.0.
"loopcond");
// Create the "after loop" block and insert it.
- BasicBlock *LoopEndBB = Builder.GetInsertBlock();
BasicBlock *AfterBB = BasicBlock::Create(getGlobalContext(), "afterloop", TheFunction);
// Insert the conditional branch into the end of LoopEndBB.
return BodyVal;
}
-
Function *PrototypeAST::Codegen() {
// Make the function type: double(double,double) etc.
std::vector<const Type*> Doubles(Args.size(),
}
}
-
Function *FunctionAST::Codegen() {
NamedValues.clear();
// Add all arguments to the symbol table and create their allocas.
Proto->CreateArgumentAllocas(TheFunction);
-
+
if (Value *RetVal = Body->Codegen()) {
// Finish off the function.
Builder.CreateRet(RetVal);
}
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.
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['='] = 2;
getNextToken();
// Make the module, which holds all the code.
- TheModule = new Module("my cool jit", getGlobalContext());
-
- ExistingModuleProvider *OurModuleProvider =
- new ExistingModuleProvider(TheModule);
-
- // Create the JIT. This takes ownership of the module and module provider.
- TheExecutionEngine = EngineBuilder(OurModuleProvider).create();
+ 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);
+ }
- FunctionPassManager OurFPM(OurModuleProvider);
+ 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());
// Promote allocas to registers.
OurFPM.add(createPromoteMemoryToRegisterPass());
// Do simple "peephole" optimizations and bit-twiddling optzns.
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<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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