llvm-6502/examples/Kaleidoscope/toy.cpp
Owen Anderson 0a5372ed3e Begin the painful process of tearing apart the rat'ss nest that is Constants.cpp and ConstantFold.cpp.
This involves temporarily hard wiring some parts to use the global context.  This isn't ideal, but it's
the only way I could figure out to make this process vaguely incremental.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75445 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-13 04:09:18 +00:00

1141 lines
32 KiB
C++

#include "llvm/DerivedTypes.h"
#include "llvm/ExecutionEngine/ExecutionEngine.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/Target/TargetSelect.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Support/IRBuilder.h"
#include <cstdio>
#include <string>
#include <map>
#include <vector>
using namespace llvm;
//===----------------------------------------------------------------------===//
// Lexer
//===----------------------------------------------------------------------===//
// The lexer returns tokens [0-255] if it is an unknown character, otherwise one
// of these for known things.
enum Token {
tok_eof = -1,
// commands
tok_def = -2, tok_extern = -3,
// primary
tok_identifier = -4, tok_number = -5,
// control
tok_if = -6, tok_then = -7, tok_else = -8,
tok_for = -9, tok_in = -10,
// operators
tok_binary = -11, tok_unary = -12,
// var definition
tok_var = -13
};
static std::string IdentifierStr; // Filled in if tok_identifier
static double NumVal; // Filled in if tok_number
/// gettok - Return the next token from standard input.
static int gettok() {
static int LastChar = ' ';
// Skip any whitespace.
while (isspace(LastChar))
LastChar = getchar();
if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
IdentifierStr = LastChar;
while (isalnum((LastChar = getchar())))
IdentifierStr += LastChar;
if (IdentifierStr == "def") return tok_def;
if (IdentifierStr == "extern") return tok_extern;
if (IdentifierStr == "if") return tok_if;
if (IdentifierStr == "then") return tok_then;
if (IdentifierStr == "else") return tok_else;
if (IdentifierStr == "for") return tok_for;
if (IdentifierStr == "in") return tok_in;
if (IdentifierStr == "binary") return tok_binary;
if (IdentifierStr == "unary") return tok_unary;
if (IdentifierStr == "var") return tok_var;
return tok_identifier;
}
if (isdigit(LastChar) || LastChar == '.') { // Number: [0-9.]+
std::string NumStr;
do {
NumStr += LastChar;
LastChar = getchar();
} while (isdigit(LastChar) || LastChar == '.');
NumVal = strtod(NumStr.c_str(), 0);
return tok_number;
}
if (LastChar == '#') {
// Comment until end of line.
do LastChar = getchar();
while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
if (LastChar != EOF)
return gettok();
}
// Check for end of file. Don't eat the EOF.
if (LastChar == EOF)
return tok_eof;
// Otherwise, just return the character as its ascii value.
int ThisChar = LastChar;
LastChar = getchar();
return ThisChar;
}
//===----------------------------------------------------------------------===//
// Abstract Syntax Tree (aka Parse Tree)
//===----------------------------------------------------------------------===//
/// ExprAST - Base class for all expression nodes.
class ExprAST {
public:
virtual ~ExprAST() {}
virtual Value *Codegen() = 0;
};
/// NumberExprAST - Expression class for numeric literals like "1.0".
class NumberExprAST : public ExprAST {
double Val;
public:
NumberExprAST(double val) : Val(val) {}
virtual Value *Codegen();
};
/// VariableExprAST - Expression class for referencing a variable, like "a".
class VariableExprAST : public ExprAST {
std::string Name;
public:
VariableExprAST(const std::string &name) : Name(name) {}
const std::string &getName() const { return Name; }
virtual Value *Codegen();
};
/// UnaryExprAST - Expression class for a unary operator.
class UnaryExprAST : public ExprAST {
char Opcode;
ExprAST *Operand;
public:
UnaryExprAST(char opcode, ExprAST *operand)
: Opcode(opcode), Operand(operand) {}
virtual Value *Codegen();
};
/// BinaryExprAST - Expression class for a binary operator.
class BinaryExprAST : public ExprAST {
char Op;
ExprAST *LHS, *RHS;
public:
BinaryExprAST(char op, ExprAST *lhs, ExprAST *rhs)
: Op(op), LHS(lhs), RHS(rhs) {}
virtual Value *Codegen();
};
/// CallExprAST - Expression class for function calls.
class CallExprAST : public ExprAST {
std::string Callee;
std::vector<ExprAST*> Args;
public:
CallExprAST(const std::string &callee, std::vector<ExprAST*> &args)
: Callee(callee), Args(args) {}
virtual Value *Codegen();
};
/// IfExprAST - Expression class for if/then/else.
class IfExprAST : public ExprAST {
ExprAST *Cond, *Then, *Else;
public:
IfExprAST(ExprAST *cond, ExprAST *then, ExprAST *_else)
: Cond(cond), Then(then), Else(_else) {}
virtual Value *Codegen();
};
/// ForExprAST - Expression class for for/in.
class ForExprAST : public ExprAST {
std::string VarName;
ExprAST *Start, *End, *Step, *Body;
public:
ForExprAST(const std::string &varname, ExprAST *start, ExprAST *end,
ExprAST *step, ExprAST *body)
: VarName(varname), Start(start), End(end), Step(step), Body(body) {}
virtual Value *Codegen();
};
/// VarExprAST - Expression class for var/in
class VarExprAST : public ExprAST {
std::vector<std::pair<std::string, ExprAST*> > VarNames;
ExprAST *Body;
public:
VarExprAST(const std::vector<std::pair<std::string, ExprAST*> > &varnames,
ExprAST *body)
: VarNames(varnames), Body(body) {}
virtual Value *Codegen();
};
/// PrototypeAST - This class represents the "prototype" for a function,
/// which captures its argument names as well as if it is an operator.
class PrototypeAST {
std::string Name;
std::vector<std::string> Args;
bool isOperator;
unsigned Precedence; // Precedence if a binary op.
public:
PrototypeAST(const std::string &name, const std::vector<std::string> &args,
bool isoperator = false, unsigned prec = 0)
: Name(name), Args(args), isOperator(isoperator), Precedence(prec) {}
bool isUnaryOp() const { return isOperator && Args.size() == 1; }
bool isBinaryOp() const { return isOperator && Args.size() == 2; }
char getOperatorName() const {
assert(isUnaryOp() || isBinaryOp());
return Name[Name.size()-1];
}
unsigned getBinaryPrecedence() const { return Precedence; }
Function *Codegen();
void CreateArgumentAllocas(Function *F);
};
/// FunctionAST - This class represents a function definition itself.
class FunctionAST {
PrototypeAST *Proto;
ExprAST *Body;
public:
FunctionAST(PrototypeAST *proto, ExprAST *body)
: Proto(proto), Body(body) {}
Function *Codegen();
};
//===----------------------------------------------------------------------===//
// Parser
//===----------------------------------------------------------------------===//
/// CurTok/getNextToken - Provide a simple token buffer. CurTok is the current
/// token the parser it looking at. getNextToken reads another token from the
/// lexer and updates CurTok with its results.
static int CurTok;
static int getNextToken() {
return CurTok = gettok();
}
/// BinopPrecedence - This holds the precedence for each binary operator that is
/// defined.
static std::map<char, int> BinopPrecedence;
/// GetTokPrecedence - Get the precedence of the pending binary operator token.
static int GetTokPrecedence() {
if (!isascii(CurTok))
return -1;
// Make sure it's a declared binop.
int TokPrec = BinopPrecedence[CurTok];
if (TokPrec <= 0) return -1;
return TokPrec;
}
/// Error* - These are little helper functions for error handling.
ExprAST *Error(const char *Str) { fprintf(stderr, "Error: %s\n", Str);return 0;}
PrototypeAST *ErrorP(const char *Str) { Error(Str); return 0; }
FunctionAST *ErrorF(const char *Str) { Error(Str); return 0; }
static ExprAST *ParseExpression();
/// identifierexpr
/// ::= identifier
/// ::= identifier '(' expression* ')'
static ExprAST *ParseIdentifierExpr() {
std::string IdName = IdentifierStr;
getNextToken(); // eat identifier.
if (CurTok != '(') // Simple variable ref.
return new VariableExprAST(IdName);
// Call.
getNextToken(); // eat (
std::vector<ExprAST*> Args;
if (CurTok != ')') {
while (1) {
ExprAST *Arg = ParseExpression();
if (!Arg) return 0;
Args.push_back(Arg);
if (CurTok == ')') break;
if (CurTok != ',')
return Error("Expected ')' or ',' in argument list");
getNextToken();
}
}
// Eat the ')'.
getNextToken();
return new CallExprAST(IdName, Args);
}
/// numberexpr ::= number
static ExprAST *ParseNumberExpr() {
ExprAST *Result = new NumberExprAST(NumVal);
getNextToken(); // consume the number
return Result;
}
/// parenexpr ::= '(' expression ')'
static ExprAST *ParseParenExpr() {
getNextToken(); // eat (.
ExprAST *V = ParseExpression();
if (!V) return 0;
if (CurTok != ')')
return Error("expected ')'");
getNextToken(); // eat ).
return V;
}
/// ifexpr ::= 'if' expression 'then' expression 'else' expression
static ExprAST *ParseIfExpr() {
getNextToken(); // eat the if.
// condition.
ExprAST *Cond = ParseExpression();
if (!Cond) return 0;
if (CurTok != tok_then)
return Error("expected then");
getNextToken(); // eat the then
ExprAST *Then = ParseExpression();
if (Then == 0) return 0;
if (CurTok != tok_else)
return Error("expected else");
getNextToken();
ExprAST *Else = ParseExpression();
if (!Else) return 0;
return new IfExprAST(Cond, Then, Else);
}
/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
static ExprAST *ParseForExpr() {
getNextToken(); // eat the for.
if (CurTok != tok_identifier)
return Error("expected identifier after for");
std::string IdName = IdentifierStr;
getNextToken(); // eat identifier.
if (CurTok != '=')
return Error("expected '=' after for");
getNextToken(); // eat '='.
ExprAST *Start = ParseExpression();
if (Start == 0) return 0;
if (CurTok != ',')
return Error("expected ',' after for start value");
getNextToken();
ExprAST *End = ParseExpression();
if (End == 0) return 0;
// The step value is optional.
ExprAST *Step = 0;
if (CurTok == ',') {
getNextToken();
Step = ParseExpression();
if (Step == 0) return 0;
}
if (CurTok != tok_in)
return Error("expected 'in' after for");
getNextToken(); // eat 'in'.
ExprAST *Body = ParseExpression();
if (Body == 0) return 0;
return new ForExprAST(IdName, Start, End, Step, Body);
}
/// varexpr ::= 'var' identifier ('=' expression)?
// (',' identifier ('=' expression)?)* 'in' expression
static ExprAST *ParseVarExpr() {
getNextToken(); // eat the var.
std::vector<std::pair<std::string, ExprAST*> > VarNames;
// At least one variable name is required.
if (CurTok != tok_identifier)
return Error("expected identifier after var");
while (1) {
std::string Name = IdentifierStr;
getNextToken(); // eat identifier.
// Read the optional initializer.
ExprAST *Init = 0;
if (CurTok == '=') {
getNextToken(); // eat the '='.
Init = ParseExpression();
if (Init == 0) return 0;
}
VarNames.push_back(std::make_pair(Name, Init));
// End of var list, exit loop.
if (CurTok != ',') break;
getNextToken(); // eat the ','.
if (CurTok != tok_identifier)
return Error("expected identifier list after var");
}
// At this point, we have to have 'in'.
if (CurTok != tok_in)
return Error("expected 'in' keyword after 'var'");
getNextToken(); // eat 'in'.
ExprAST *Body = ParseExpression();
if (Body == 0) return 0;
return new VarExprAST(VarNames, Body);
}
/// primary
/// ::= identifierexpr
/// ::= numberexpr
/// ::= parenexpr
/// ::= ifexpr
/// ::= forexpr
/// ::= varexpr
static ExprAST *ParsePrimary() {
switch (CurTok) {
default: return Error("unknown token when expecting an expression");
case tok_identifier: return ParseIdentifierExpr();
case tok_number: return ParseNumberExpr();
case '(': return ParseParenExpr();
case tok_if: return ParseIfExpr();
case tok_for: return ParseForExpr();
case tok_var: return ParseVarExpr();
}
}
/// unary
/// ::= primary
/// ::= '!' unary
static ExprAST *ParseUnary() {
// If the current token is not an operator, it must be a primary expr.
if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')
return ParsePrimary();
// If this is a unary operator, read it.
int Opc = CurTok;
getNextToken();
if (ExprAST *Operand = ParseUnary())
return new UnaryExprAST(Opc, Operand);
return 0;
}
/// binoprhs
/// ::= ('+' unary)*
static ExprAST *ParseBinOpRHS(int ExprPrec, ExprAST *LHS) {
// If this is a binop, find its precedence.
while (1) {
int TokPrec = GetTokPrecedence();
// If this is a binop that binds at least as tightly as the current binop,
// consume it, otherwise we are done.
if (TokPrec < ExprPrec)
return LHS;
// Okay, we know this is a binop.
int BinOp = CurTok;
getNextToken(); // eat binop
// Parse the unary expression after the binary operator.
ExprAST *RHS = ParseUnary();
if (!RHS) return 0;
// If BinOp binds less tightly with RHS than the operator after RHS, let
// the pending operator take RHS as its LHS.
int NextPrec = GetTokPrecedence();
if (TokPrec < NextPrec) {
RHS = ParseBinOpRHS(TokPrec+1, RHS);
if (RHS == 0) return 0;
}
// Merge LHS/RHS.
LHS = new BinaryExprAST(BinOp, LHS, RHS);
}
}
/// expression
/// ::= unary binoprhs
///
static ExprAST *ParseExpression() {
ExprAST *LHS = ParseUnary();
if (!LHS) return 0;
return ParseBinOpRHS(0, LHS);
}
/// prototype
/// ::= id '(' id* ')'
/// ::= binary LETTER number? (id, id)
/// ::= unary LETTER (id)
static PrototypeAST *ParsePrototype() {
std::string FnName;
unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
unsigned BinaryPrecedence = 30;
switch (CurTok) {
default:
return ErrorP("Expected function name in prototype");
case tok_identifier:
FnName = IdentifierStr;
Kind = 0;
getNextToken();
break;
case tok_unary:
getNextToken();
if (!isascii(CurTok))
return ErrorP("Expected unary operator");
FnName = "unary";
FnName += (char)CurTok;
Kind = 1;
getNextToken();
break;
case tok_binary:
getNextToken();
if (!isascii(CurTok))
return ErrorP("Expected binary operator");
FnName = "binary";
FnName += (char)CurTok;
Kind = 2;
getNextToken();
// Read the precedence if present.
if (CurTok == tok_number) {
if (NumVal < 1 || NumVal > 100)
return ErrorP("Invalid precedecnce: must be 1..100");
BinaryPrecedence = (unsigned)NumVal;
getNextToken();
}
break;
}
if (CurTok != '(')
return ErrorP("Expected '(' in prototype");
std::vector<std::string> ArgNames;
while (getNextToken() == tok_identifier)
ArgNames.push_back(IdentifierStr);
if (CurTok != ')')
return ErrorP("Expected ')' in prototype");
// success.
getNextToken(); // eat ')'.
// Verify right number of names for operator.
if (Kind && ArgNames.size() != Kind)
return ErrorP("Invalid number of operands for operator");
return new PrototypeAST(FnName, ArgNames, Kind != 0, BinaryPrecedence);
}
/// definition ::= 'def' prototype expression
static FunctionAST *ParseDefinition() {
getNextToken(); // eat def.
PrototypeAST *Proto = ParsePrototype();
if (Proto == 0) return 0;
if (ExprAST *E = ParseExpression())
return new FunctionAST(Proto, E);
return 0;
}
/// toplevelexpr ::= expression
static FunctionAST *ParseTopLevelExpr() {
if (ExprAST *E = ParseExpression()) {
// Make an anonymous proto.
PrototypeAST *Proto = new PrototypeAST("", std::vector<std::string>());
return new FunctionAST(Proto, E);
}
return 0;
}
/// external ::= 'extern' prototype
static PrototypeAST *ParseExtern() {
getNextToken(); // eat extern.
return ParsePrototype();
}
//===----------------------------------------------------------------------===//
// Code Generation
//===----------------------------------------------------------------------===//
static Module *TheModule;
static IRBuilder<> Builder(getGlobalContext());
static std::map<std::string, AllocaInst*> NamedValues;
static FunctionPassManager *TheFPM;
Value *ErrorV(const char *Str) { Error(Str); return 0; }
/// CreateEntryBlockAlloca - Create an alloca instruction in the entry block of
/// the function. This is used for mutable variables etc.
static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction,
const std::string &VarName) {
IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
TheFunction->getEntryBlock().begin());
return TmpB.CreateAlloca(Type::DoubleTy, 0, VarName.c_str());
}
Value *NumberExprAST::Codegen() {
return ConstantFP::get(APFloat(Val));
}
Value *VariableExprAST::Codegen() {
// Look this variable up in the function.
Value *V = NamedValues[Name];
if (V == 0) return ErrorV("Unknown variable name");
// Load the value.
return Builder.CreateLoad(V, Name.c_str());
}
Value *UnaryExprAST::Codegen() {
Value *OperandV = Operand->Codegen();
if (OperandV == 0) return 0;
Function *F = TheModule->getFunction(std::string("unary")+Opcode);
if (F == 0)
return ErrorV("Unknown unary operator");
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 == '=') {
// Assignment requires the LHS to be an identifier.
VariableExprAST *LHSE = dynamic_cast<VariableExprAST*>(LHS);
if (!LHSE)
return ErrorV("destination of '=' must be a variable");
// Codegen the RHS.
Value *Val = RHS->Codegen();
if (Val == 0) return 0;
// Look up the name.
Value *Variable = NamedValues[LHSE->getName()];
if (Variable == 0) return ErrorV("Unknown variable name");
Builder.CreateStore(Val, Variable);
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 '<':
L = Builder.CreateFCmpULT(L, R, "cmptmp");
// Convert bool 0/1 to double 0.0 or 1.0
return Builder.CreateUIToFP(L, Type::DoubleTy, "booltmp");
default: break;
}
// If it wasn't a builtin binary operator, it must be a user defined one. Emit
// a call to it.
Function *F = TheModule->getFunction(std::string("binary")+Op);
assert(F && "binary operator not found!");
Value *Ops[] = { L, R };
return Builder.CreateCall(F, Ops, Ops+2, "binop");
}
Value *CallExprAST::Codegen() {
// Look up the name in the global module table.
Function *CalleeF = TheModule->getFunction(Callee);
if (CalleeF == 0)
return ErrorV("Unknown function referenced");
// If argument mismatch error.
if (CalleeF->arg_size() != Args.size())
return ErrorV("Incorrect # arguments passed");
std::vector<Value*> ArgsV;
for (unsigned i = 0, e = Args.size(); i != e; ++i) {
ArgsV.push_back(Args[i]->Codegen());
if (ArgsV.back() == 0) return 0;
}
return Builder.CreateCall(CalleeF, ArgsV.begin(), ArgsV.end(), "calltmp");
}
Value *IfExprAST::Codegen() {
Value *CondV = Cond->Codegen();
if (CondV == 0) return 0;
// Convert condition to a bool by comparing equal to 0.0.
CondV = Builder.CreateFCmpONE(CondV,
ConstantFP::get(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");
Builder.CreateCondBr(CondV, ThenBB, ElseBB);
// Emit then value.
Builder.SetInsertPoint(ThenBB);
Value *ThenV = Then->Codegen();
if (ThenV == 0) return 0;
Builder.CreateBr(MergeBB);
// Codegen of 'Then' can change the current block, update ThenBB for the PHI.
ThenBB = Builder.GetInsertBlock();
// Emit else block.
TheFunction->getBasicBlockList().push_back(ElseBB);
Builder.SetInsertPoint(ElseBB);
Value *ElseV = Else->Codegen();
if (ElseV == 0) return 0;
Builder.CreateBr(MergeBB);
// Codegen of 'Else' can change the current block, update ElseBB for the PHI.
ElseBB = Builder.GetInsertBlock();
// Emit merge block.
TheFunction->getBasicBlockList().push_back(MergeBB);
Builder.SetInsertPoint(MergeBB);
PHINode *PN = Builder.CreatePHI(Type::DoubleTy, "iftmp");
PN->addIncoming(ThenV, ThenBB);
PN->addIncoming(ElseV, ElseBB);
return PN;
}
Value *ForExprAST::Codegen() {
// Output this as:
// var = alloca double
// ...
// start = startexpr
// store start -> var
// goto loop
// loop:
// ...
// bodyexpr
// ...
// loopend:
// step = stepexpr
// endcond = endexpr
//
// curvar = load var
// nextvar = curvar + step
// store nextvar -> var
// br endcond, loop, endloop
// outloop:
Function *TheFunction = Builder.GetInsertBlock()->getParent();
// Create an alloca for the variable in the entry block.
AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
// Emit the start code first, without 'variable' in scope.
Value *StartVal = Start->Codegen();
if (StartVal == 0) return 0;
// Store the value into the alloca.
Builder.CreateStore(StartVal, Alloca);
// Make the new basic block for the loop header, inserting after current
// block.
BasicBlock *LoopBB = BasicBlock::Create("loop", TheFunction);
// Insert an explicit fall through from the current block to the LoopBB.
Builder.CreateBr(LoopBB);
// Start insertion in LoopBB.
Builder.SetInsertPoint(LoopBB);
// Within the loop, the variable is defined equal to the PHI node. If it
// shadows an existing variable, we have to restore it, so save it now.
AllocaInst *OldVal = NamedValues[VarName];
NamedValues[VarName] = Alloca;
// Emit the body of the loop. This, like any other expr, can change the
// current BB. Note that we ignore the value computed by the body, but don't
// allow an error.
if (Body->Codegen() == 0)
return 0;
// Emit the step value.
Value *StepVal;
if (Step) {
StepVal = Step->Codegen();
if (StepVal == 0) return 0;
} else {
// If not specified, use 1.0.
StepVal = ConstantFP::get(APFloat(1.0));
}
// Compute the end condition.
Value *EndCond = End->Codegen();
if (EndCond == 0) return EndCond;
// 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");
Builder.CreateStore(NextVar, Alloca);
// Convert condition to a bool by comparing equal to 0.0.
EndCond = Builder.CreateFCmpONE(EndCond,
ConstantFP::get(APFloat(0.0)),
"loopcond");
// Create the "after loop" block and insert it.
BasicBlock *AfterBB = BasicBlock::Create("afterloop", TheFunction);
// Insert the conditional branch into the end of LoopEndBB.
Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
// Any new code will be inserted in AfterBB.
Builder.SetInsertPoint(AfterBB);
// Restore the unshadowed variable.
if (OldVal)
NamedValues[VarName] = OldVal;
else
NamedValues.erase(VarName);
// for expr always returns 0.0.
return TheFunction->getContext()->getNullValue(Type::DoubleTy);
}
Value *VarExprAST::Codegen() {
std::vector<AllocaInst *> OldBindings;
Function *TheFunction = Builder.GetInsertBlock()->getParent();
// Register all variables and emit their initializer.
for (unsigned i = 0, e = VarNames.size(); i != e; ++i) {
const std::string &VarName = VarNames[i].first;
ExprAST *Init = VarNames[i].second;
// Emit the initializer before adding the variable to scope, this prevents
// the initializer from referencing the variable itself, and permits stuff
// like this:
// var a = 1 in
// var a = a in ... # refers to outer 'a'.
Value *InitVal;
if (Init) {
InitVal = Init->Codegen();
if (InitVal == 0) return 0;
} else { // If not specified, use 0.0.
InitVal = ConstantFP::get(APFloat(0.0));
}
AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
Builder.CreateStore(InitVal, Alloca);
// Remember the old variable binding so that we can restore the binding when
// we unrecurse.
OldBindings.push_back(NamedValues[VarName]);
// Remember this binding.
NamedValues[VarName] = Alloca;
}
// Codegen the body, now that all vars are in scope.
Value *BodyVal = Body->Codegen();
if (BodyVal == 0) return 0;
// Pop all our variables from scope.
for (unsigned i = 0, e = VarNames.size(); i != e; ++i)
NamedValues[VarNames[i].first] = OldBindings[i];
// Return the body computation.
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);
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.
if (F->getName() != Name) {
// Delete the one we just made and get the existing one.
F->eraseFromParent();
F = TheModule->getFunction(Name);
// If F already has a body, reject this.
if (!F->empty()) {
ErrorF("redefinition of function");
return 0;
}
// If F took a different number of args, reject.
if (F->arg_size() != Args.size()) {
ErrorF("redefinition of function with different # args");
return 0;
}
}
// Set names for all arguments.
unsigned Idx = 0;
for (Function::arg_iterator AI = F->arg_begin(); Idx != Args.size();
++AI, ++Idx)
AI->setName(Args[Idx]);
return F;
}
/// CreateArgumentAllocas - Create an alloca for each argument and register the
/// argument in the symbol table so that references to it will succeed.
void PrototypeAST::CreateArgumentAllocas(Function *F) {
Function::arg_iterator AI = F->arg_begin();
for (unsigned Idx = 0, e = Args.size(); Idx != e; ++Idx, ++AI) {
// Create an alloca for this variable.
AllocaInst *Alloca = CreateEntryBlockAlloca(F, Args[Idx]);
// Store the initial value into the alloca.
Builder.CreateStore(AI, Alloca);
// Add arguments to variable symbol table.
NamedValues[Args[Idx]] = Alloca;
}
}
Function *FunctionAST::Codegen() {
NamedValues.clear();
Function *TheFunction = Proto->Codegen();
if (TheFunction == 0)
return 0;
// If this is an operator, install it.
if (Proto->isBinaryOp())
BinopPrecedence[Proto->getOperatorName()] = Proto->getBinaryPrecedence();
// Create a new basic block to start insertion into.
BasicBlock *BB = BasicBlock::Create("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);
// Validate the generated code, checking for consistency.
verifyFunction(*TheFunction);
// Optimize the function.
TheFPM->run(*TheFunction);
return TheFunction;
}
// Error reading body, remove function.
TheFunction->eraseFromParent();
if (Proto->isBinaryOp())
BinopPrecedence.erase(Proto->getOperatorName());
return 0;
}
//===----------------------------------------------------------------------===//
// Top-Level parsing and JIT Driver
//===----------------------------------------------------------------------===//
static ExecutionEngine *TheExecutionEngine;
static void HandleDefinition() {
if (FunctionAST *F = ParseDefinition()) {
if (Function *LF = F->Codegen()) {
fprintf(stderr, "Read function definition:");
LF->dump();
}
} else {
// Skip token for error recovery.
getNextToken();
}
}
static void HandleExtern() {
if (PrototypeAST *P = ParseExtern()) {
if (Function *F = P->Codegen()) {
fprintf(stderr, "Read extern: ");
F->dump();
}
} else {
// Skip token for error recovery.
getNextToken();
}
}
static void HandleTopLevelExpression() {
// 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.
void *FPtr = TheExecutionEngine->getPointerToFunction(LF);
// Cast it to the right type (takes no arguments, returns a double) so we
// can call it as a native function.
double (*FP)() = (double (*)())(intptr_t)FPtr;
fprintf(stderr, "Evaluated to %f\n", FP());
}
} else {
// Skip token for error recovery.
getNextToken();
}
}
/// top ::= definition | external | expression | ';'
static void MainLoop() {
while (1) {
fprintf(stderr, "ready> ");
switch (CurTok) {
case tok_eof: return;
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.
//===----------------------------------------------------------------------===//
/// putchard - putchar that takes a double and returns 0.
extern "C"
double putchard(double X) {
putchar((char)X);
return 0;
}
/// printd - printf that takes a double prints it as "%f\n", returning 0.
extern "C"
double printd(double X) {
printf("%f\n", X);
return 0;
}
//===----------------------------------------------------------------------===//
// Main driver code.
//===----------------------------------------------------------------------===//
int main() {
InitializeNativeTarget();
LLVMContext Context;
// Install standard binary operators.
// 1 is lowest precedence.
BinopPrecedence['='] = 2;
BinopPrecedence['<'] = 10;
BinopPrecedence['+'] = 20;
BinopPrecedence['-'] = 20;
BinopPrecedence['*'] = 40; // highest.
// Prime the first token.
fprintf(stderr, "ready> ");
getNextToken();
// Make the module, which holds all the code.
TheModule = new Module("my cool jit", Context);
// Create the JIT.
TheExecutionEngine = ExecutionEngine::create(TheModule);
{
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());
// 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();
} // Free module provider (and thus the module) and pass manager.
return 0;
}