Welcome to Chapter 7 of the "Implementing a language with LLVM" tutorial. In chapters 1 through 6, we've built a very @@ -66,10 +66,10 @@ support for this, though the way it works is a bit unexpected for some.
To understand why mutable variables cause complexities in SSA construction, @@ -140,10 +140,10 @@ logic.
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. @@ -321,11 +321,10 @@ variables now!
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 @@ -378,11 +377,10 @@ Kaleidoscope to support new variable definitions.
The symbol table in Kaleidoscope is managed at code generation time by the @@ -422,14 +420,15 @@ function:
/// the function. This is used for mutable variables etc. static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction, const std::string &VarName) { - LLVMBuilder TmpB(&TheFunction->getEntryBlock(), - TheFunction->getEntryBlock().begin()); - return TmpB.CreateAlloca(Type::DoubleTy, 0, VarName.c_str()); + IRBuilder<> TmpB(&TheFunction->getEntryBlock(), + TheFunction->getEntryBlock().begin()); + return TmpB.CreateAlloca(Type::getDoubleTy(getGlobalContext()), 0, + VarName.c_str()); }This funny looking code creates an LLVMBuilder object that is pointing at +
This funny looking code creates an IRBuilder object that is pointing at the first instruction (.begin()) of the entry block. It then creates an alloca with the expected name and returns it. Because all values in Kaleidoscope are doubles, there is no need to pass in a type to use.
@@ -479,7 +478,7 @@ the unabridged code): // 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); ... @@ -556,12 +555,12 @@ then: ; preds = %entry else: ; preds = %entry %x3 = load double* %x1 - %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) %x4 = load double* %x1 - %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 @@ -594,11 +593,11 @@ then: br 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 br label %ifcont ifcont: ; preds = %else, %then @@ -624,11 +623,11 @@ entry: 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: @@ -647,10 +646,10 @@ we'll add the assignment operator.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 @@ -744,11 +743,10 @@ add this next!
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. @@ -923,7 +921,7 @@ that we replace in OldBindings.
InitVal = Init->Codegen(); if (InitVal == 0) return 0; } else { // If not specified, use 0.0. - InitVal = ConstantFP::get(Type::DoubleTy, APFloat(0.0)); + InitVal = ConstantFP::get(getGlobalContext(), APFloat(0.0)); } AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName); @@ -978,10 +976,10 @@ anywhere in sight.Here is the complete code listing for our running example, enhanced with mutable @@ -1003,13 +1001,16 @@ variables and var/in support. To build this example, use:
#include "llvm/DerivedTypes.h"
#include "llvm/ExecutionEngine/ExecutionEngine.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"
-#include "llvm/Support/LLVMBuilder.h"
+#include "llvm/Support/IRBuilder.h"
#include <cstdio>
#include <string>
#include <map>
@@ -1192,7 +1193,8 @@ public:
};
/// 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;
@@ -1234,7 +1236,7 @@ public:
//===----------------------------------------------------------------------===//
/// 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() {
@@ -1282,11 +1284,11 @@ static ExprAST *ParseIdentifierExpr() {
ExprAST *Arg = ParseExpression();
if (!Arg) return 0;
Args.push_back(Arg);
-
+
if (CurTok == ')') break;
-
+
if (CurTok != ',')
- return Error("Expected ')'");
+ return Error("Expected ')' or ',' in argument list");
getNextToken();
}
}
@@ -1429,7 +1431,6 @@ static ExprAST *ParseVarExpr() {
return new VarExprAST(VarNames, Body);
}
-
/// primary
/// ::= identifierexpr
/// ::= numberexpr
@@ -1515,7 +1516,7 @@ static ExprAST *ParseExpression() {
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) {
@@ -1605,7 +1606,7 @@ static PrototypeAST *ParseExtern() {
//===----------------------------------------------------------------------===//
static Module *TheModule;
-static LLVMFoldingBuilder Builder;
+static IRBuilder<> Builder(getGlobalContext());
static std::map<std::string, AllocaInst*> NamedValues;
static FunctionPassManager *TheFPM;
@@ -1615,14 +1616,14 @@ Value *ErrorV(const char *Str) { Error(Str); return 0; }
/// the function. This is used for mutable variables etc.
static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction,
const std::string &VarName) {
- LLVMBuilder TmpB(&TheFunction->getEntryBlock(),
- TheFunction->getEntryBlock().begin());
- return TmpB.CreateAlloca(Type::DoubleTy, 0, VarName.c_str());
+ IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
+ TheFunction->getEntryBlock().begin());
+ return TmpB.CreateAlloca(Type::getDoubleTy(getGlobalContext()), 0,
+ VarName.c_str());
}
-
Value *NumberExprAST::Codegen() {
- return ConstantFP::get(Type::DoubleTy, APFloat(Val));
+ return ConstantFP::get(getGlobalContext(), APFloat(Val));
}
Value *VariableExprAST::Codegen() {
@@ -1645,7 +1646,6 @@ Value *UnaryExprAST::Codegen() {
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 == '=') {
@@ -1665,19 +1665,19 @@ Value *BinaryExprAST::Codegen() {
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
- return Builder.CreateUIToFP(L, Type::DoubleTy, "booltmp");
+ return Builder.CreateUIToFP(L, Type::getDoubleTy(getGlobalContext()),
+ "booltmp");
default: break;
}
@@ -1715,16 +1715,16 @@ Value *IfExprAST::Codegen() {
// Convert condition to a bool by comparing equal to 0.0.
CondV = Builder.CreateFCmpONE(CondV,
- ConstantFP::get(Type::DoubleTy, 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 = new BasicBlock("then", TheFunction);
- BasicBlock *ElseBB = new BasicBlock("else");
- BasicBlock *MergeBB = new BasicBlock("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);
@@ -1752,7 +1752,8 @@ Value *IfExprAST::Codegen() {
// 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);
@@ -1794,8 +1795,7 @@ Value *ForExprAST::Codegen() {
// Make the new basic block for the loop header, inserting after current
// block.
- BasicBlock *PreheaderBB = Builder.GetInsertBlock();
- BasicBlock *LoopBB = new BasicBlock("loop", TheFunction);
+ BasicBlock *LoopBB = BasicBlock::Create(getGlobalContext(), "loop", TheFunction);
// Insert an explicit fall through from the current block to the LoopBB.
Builder.CreateBr(LoopBB);
@@ -1821,7 +1821,7 @@ Value *ForExprAST::Codegen() {
if (StepVal == 0) return 0;
} else {
// If not specified, use 1.0.
- StepVal = ConstantFP::get(Type::DoubleTy, APFloat(1.0));
+ StepVal = ConstantFP::get(getGlobalContext(), APFloat(1.0));
}
// Compute the end condition.
@@ -1831,17 +1831,16 @@ Value *ForExprAST::Codegen() {
// 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.
EndCond = Builder.CreateFCmpONE(EndCond,
- ConstantFP::get(Type::DoubleTy, APFloat(0.0)),
+ ConstantFP::get(getGlobalContext(), APFloat(0.0)),
"loopcond");
// Create the "after loop" block and insert it.
- BasicBlock *LoopEndBB = Builder.GetInsertBlock();
- BasicBlock *AfterBB = new BasicBlock("afterloop", TheFunction);
+ BasicBlock *AfterBB = BasicBlock::Create(getGlobalContext(), "afterloop", TheFunction);
// Insert the conditional branch into the end of LoopEndBB.
Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
@@ -1857,7 +1856,7 @@ Value *ForExprAST::Codegen() {
// for expr always returns 0.0.
- return Constant::getNullValue(Type::DoubleTy);
+ return Constant::getNullValue(Type::getDoubleTy(getGlobalContext()));
}
Value *VarExprAST::Codegen() {
@@ -1880,7 +1879,7 @@ Value *VarExprAST::Codegen() {
InitVal = Init->Codegen();
if (InitVal == 0) return 0;
} else { // If not specified, use 0.0.
- InitVal = ConstantFP::get(Type::DoubleTy, APFloat(0.0));
+ InitVal = ConstantFP::get(getGlobalContext(), APFloat(0.0));
}
AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
@@ -1906,13 +1905,14 @@ Value *VarExprAST::Codegen() {
return BodyVal;
}
-
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<const Type*> Doubles(Args.size(),
+ Type::getDoubleTy(getGlobalContext()));
+ FunctionType *FT = FunctionType::get(Type::getDoubleTy(getGlobalContext()),
+ Doubles, false);
- Function *F = new Function(FT, Function::ExternalLinkage, Name, TheModule);
+ Function *F = Function::Create(FT, Function::ExternalLinkage, Name, TheModule);
// If F conflicted, there was already something named 'Name'. If it has a
// body, don't allow redefinition or reextern.
@@ -1959,7 +1959,6 @@ void PrototypeAST::CreateArgumentAllocas(Function *F) {
}
}
-
Function *FunctionAST::Codegen() {
NamedValues.clear();
@@ -1972,12 +1971,12 @@ Function *FunctionAST::Codegen() {
BinopPrecedence[Proto->getOperatorName()] = Proto->getBinaryPrecedence();
// Create a new basic block to start insertion into.
- BasicBlock *BB = new BasicBlock("entry", TheFunction);
+ BasicBlock *BB = BasicBlock::Create(getGlobalContext(), "entry", TheFunction);
Builder.SetInsertPoint(BB);
// 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);
@@ -2030,7 +2029,7 @@ static void HandleExtern() {
}
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.
@@ -2038,7 +2037,7 @@ static void HandleTopLevelExpression() {
// 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 {
@@ -2053,7 +2052,7 @@ static void MainLoop() {
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;
@@ -2061,8 +2060,6 @@ static void MainLoop() {
}
}
-
-
//===----------------------------------------------------------------------===//
// "Library" functions that can be "extern'd" from user code.
//===----------------------------------------------------------------------===//
@@ -2086,6 +2083,9 @@ double printd(double X) {
//===----------------------------------------------------------------------===//
int main() {
+ InitializeNativeTarget();
+ LLVMContext &Context = getGlobalContext();
+
// Install standard binary operators.
// 1 is lowest precedence.
BinopPrecedence['='] = 2;
@@ -2099,47 +2099,53 @@ int main() {
getNextToken();
// Make the module, which holds all the code.
- TheModule = new Module("my cool jit");
-
- // 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()));
- // Promote allocas to registers.
- OurFPM.add(createPromoteMemoryToRegisterPass());
- // 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());
+ FunctionPassManager OurFPM(TheModule);
- // Set the global so the code gen can use this.
- TheFPM = &OurFPM;
+ // 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.
+ 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();
- // Run the main "interpreter loop" now.
- MainLoop();
-
- TheFPM = 0;
-
- // Print out all of the generated code.
- TheModule->dump();
-
- } // Free module provider (and thus the module) and pass manager.
-
return 0;
}