.. contents::
:local:
-Written by `Chris Lattner <mailto:sabre@nondot.org>`_
-
Chapter 6 Introduction
======================
enum Token {
...
// operators
- tok_binary = -11, tok_unary = -12
+ tok_binary = -11,
+ tok_unary = -12
};
...
static int gettok() {
...
- 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 == "for")
+ return tok_for;
+ if (IdentifierStr == "in")
+ return tok_in;
+ if (IdentifierStr == "binary")
+ return tok_binary;
+ if (IdentifierStr == "unary")
+ return tok_unary;
return tok_identifier;
This just adds lexer support for the unary and binary keywords, like we
class PrototypeAST {
std::string Name;
std::vector<std::string> Args;
- bool isOperator;
+ 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) {}
+ PrototypeAST(const std::string &name, std::vector<std::string> Args,
+ bool IsOperator = false, unsigned Prec = 0)
+ : Name(name), Args(std::move(Args)), IsOperator(IsOperator),
+ Precedence(Prec) {}
- bool isUnaryOp() const { return isOperator && Args.size() == 1; }
- bool isBinaryOp() const { return isOperator && Args.size() == 2; }
+ bool isUnaryOp() const { return IsOperator && Args.size() == 1; }
+ bool isBinaryOp() const { return IsOperator && Args.size() == 2; }
char getOperatorName() const {
assert(isUnaryOp() || isBinaryOp());
/// prototype
/// ::= id '(' id* ')'
/// ::= binary LETTER number? (id, id)
- static PrototypeAST *ParsePrototype() {
+ static std::unique_ptr<PrototypeAST> ParsePrototype() {
std::string FnName;
unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
if (Kind && ArgNames.size() != Kind)
return ErrorP("Invalid number of operands for operator");
- return new PrototypeAST(FnName, ArgNames, Kind != 0, BinaryPrecedence);
+ return llvm::make_unique<PrototypeAST>(FnName, std::move(ArgNames), Kind != 0,
+ BinaryPrecedence);
}
This is all fairly straightforward parsing code, and we have already
Value *BinaryExprAST::Codegen() {
Value *L = LHS->Codegen();
Value *R = RHS->Codegen();
- if (L == 0 || R == 0) return 0;
+ if (!L || !R)
+ return nullptr;
switch (Op) {
- case '+': return Builder.CreateFAdd(L, R, "addtmp");
- case '-': return Builder.CreateFSub(L, R, "subtmp");
- case '*': return Builder.CreateFMul(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::getDoubleTy(getGlobalContext()),
"booltmp");
- default: break;
+ 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);
+ Function *F = TheModule->getFunction(std::string("binary") + Op);
assert(F && "binary operator not found!");
Value *Ops[2] = { L, R };
NamedValues.clear();
Function *TheFunction = Proto->Codegen();
- if (TheFunction == 0)
- return 0;
+ if (!TheFunction)
+ return nullptr;
// If this is an operator, install it.
if (Proto->isBinaryOp())
/// UnaryExprAST - Expression class for a unary operator.
class UnaryExprAST : public ExprAST {
char Opcode;
- ExprAST *Operand;
+ std::unique_ptr<ExprAST> Operand;
+
public:
- UnaryExprAST(char opcode, ExprAST *operand)
- : Opcode(opcode), Operand(operand) {}
+ UnaryExprAST(char Opcode, std::unique_ptr<ExprAST> Operand)
+ : Opcode(Opcode), Operand(std::move(Operand)) {}
virtual Value *Codegen();
};
/// unary
/// ::= primary
/// ::= '!' unary
- static ExprAST *ParseUnary() {
+ static std::unique_ptr<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;
+ if (auto Operand = ParseUnary())
+ return llvm::unique_ptr<UnaryExprAST>(Opc, std::move(Operand));
+ return nullptr;
}
The grammar we add is pretty straightforward here. If we see a unary
/// binoprhs
/// ::= ('+' unary)*
- static ExprAST *ParseBinOpRHS(int ExprPrec, ExprAST *LHS) {
+ static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
+ std::unique_ptr<ExprAST> LHS) {
...
// Parse the unary expression after the binary operator.
- ExprAST *RHS = ParseUnary();
- if (!RHS) return 0;
+ auto RHS = ParseUnary();
+ if (!RHS)
+ return nullptr;
...
}
/// expression
/// ::= unary binoprhs
///
- static ExprAST *ParseExpression() {
- ExprAST *LHS = ParseUnary();
- if (!LHS) return 0;
+ static std::unique_ptr<ExprAST> ParseExpression() {
+ auto LHS = ParseUnary();
+ if (!LHS)
+ return nullptr;
- return ParseBinOpRHS(0, LHS);
+ return ParseBinOpRHS(0, std::move(LHS));
}
With these two simple changes, we are now able to parse unary operators
/// ::= id '(' id* ')'
/// ::= binary LETTER number? (id, id)
/// ::= unary LETTER (id)
- static PrototypeAST *ParsePrototype() {
+ static std::unique_ptr<PrototypeAST> ParsePrototype() {
std::string FnName;
unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
Value *UnaryExprAST::Codegen() {
Value *OperandV = Operand->Codegen();
- if (OperandV == 0) return 0;
+ if (!OperandV)
+ return nullptr;
Function *F = TheModule->getFunction(std::string("unary")+Opcode);
- if (F == 0)
+ if (!F)
return ErrorV("Unknown unary operator");
return Builder.CreateCall(F, OperandV, "unop");
.. code-block:: bash
# Compile
- clang++ -g toy.cpp `llvm-config --cppflags --ldflags --libs core jit native` -O3 -o toy
+ clang++ -g toy.cpp `llvm-config --cxxflags --ldflags --system-libs --libs core mcjit native` -O3 -o toy
# Run
./toy
Here is the code:
-.. code-block:: c++
-
- #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/PassManager.h"
- #include "llvm/Analysis/Verifier.h"
- #include "llvm/Analysis/Passes.h"
- #include "llvm/DataLayout.h"
- #include "llvm/Transforms/Scalar.h"
- #include "llvm/Support/TargetSelect.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
- };
-
- 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;
- 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) {}
- 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();
- };
-
- /// PrototypeAST - This class represents the "prototype" for a function,
- /// 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;
- 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();
- };
-
- /// 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 is 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);
- }
-
- /// primary
- /// ::= identifierexpr
- /// ::= numberexpr
- /// ::= parenexpr
- /// ::= ifexpr
- /// ::= forexpr
- 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();
- }
- }
-
- /// 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, Value*> NamedValues;
- static FunctionPassManager *TheFPM;
-
- Value *ErrorV(const char *Str) { Error(Str); return 0; }
-
- Value *NumberExprAST::Codegen() {
- return ConstantFP::get(getGlobalContext(), APFloat(Val));
- }
-
- Value *VariableExprAST::Codegen() {
- // Look this variable up in the function.
- Value *V = NamedValues[Name];
- return V ? V : ErrorV("Unknown variable name");
- }
-
- 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() {
- Value *L = LHS->Codegen();
- Value *R = RHS->Codegen();
- if (L == 0 || R == 0) return 0;
-
- switch (Op) {
- 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::getDoubleTy(getGlobalContext()),
- "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[2] = { L, R };
- return Builder.CreateCall(F, Ops, "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, "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(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(getGlobalContext(), "then", TheFunction);
- BasicBlock *ElseBB = BasicBlock::Create(getGlobalContext(), "else");
- BasicBlock *MergeBB = BasicBlock::Create(getGlobalContext(), "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::getDoubleTy(getGlobalContext()), 2,
- "iftmp");
-
- PN->addIncoming(ThenV, ThenBB);
- PN->addIncoming(ElseV, ElseBB);
- return PN;
- }
-
- Value *ForExprAST::Codegen() {
- // Output this as:
- // ...
- // start = startexpr
- // goto loop
- // loop:
- // variable = phi [start, loopheader], [nextvariable, loopend]
- // ...
- // bodyexpr
- // ...
- // loopend:
- // step = stepexpr
- // nextvariable = variable + step
- // endcond = endexpr
- // br endcond, loop, endloop
- // outloop:
-
- // Emit the start code first, without 'variable' in scope.
- Value *StartVal = Start->Codegen();
- if (StartVal == 0) return 0;
-
- // Make the new basic block for the loop header, inserting after current
- // block.
- Function *TheFunction = Builder.GetInsertBlock()->getParent();
- BasicBlock *PreheaderBB = Builder.GetInsertBlock();
- BasicBlock *LoopBB = BasicBlock::Create(getGlobalContext(), "loop", TheFunction);
-
- // Insert an explicit fall through from the current block to the LoopBB.
- Builder.CreateBr(LoopBB);
-
- // Start insertion in LoopBB.
- Builder.SetInsertPoint(LoopBB);
-
- // Start the PHI node with an entry for Start.
- 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
- // shadows an existing variable, we have to restore it, so save it now.
- Value *OldVal = NamedValues[VarName];
- NamedValues[VarName] = Variable;
-
- // 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(getGlobalContext(), APFloat(1.0));
- }
-
- Value *NextVar = Builder.CreateFAdd(Variable, StepVal, "nextvar");
-
- // Compute the end condition.
- Value *EndCond = End->Codegen();
- if (EndCond == 0) return EndCond;
-
- // Convert condition to a bool by comparing equal to 0.0.
- EndCond = Builder.CreateFCmpONE(EndCond,
- ConstantFP::get(getGlobalContext(), APFloat(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.
- Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
-
- // Any new code will be inserted in AfterBB.
- Builder.SetInsertPoint(AfterBB);
-
- // Add a new entry to the PHI node for the backedge.
- Variable->addIncoming(NextVar, LoopEndBB);
-
- // Restore the unshadowed variable.
- if (OldVal)
- NamedValues[VarName] = OldVal;
- else
- NamedValues.erase(VarName);
-
-
- // for expr always returns 0.0.
- return Constant::getNullValue(Type::getDoubleTy(getGlobalContext()));
- }
-
- Function *PrototypeAST::Codegen() {
- // Make the function type: double(double,double) etc.
- 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);
-
- // 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]);
-
- // Add arguments to variable symbol table.
- NamedValues[Args[Idx]] = AI;
- }
-
- return F;
- }
-
- 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(getGlobalContext(), "entry", TheFunction);
- Builder.SetInsertPoint(BB);
-
- 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 = getGlobalContext();
-
- // Install standard binary operators.
- // 1 is lowest precedence.
- 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. 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(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();
-
- return 0;
- }
+.. literalinclude:: ../../examples/Kaleidoscope/Chapter6/toy.cpp
+ :language: c++
`Next: Extending the language: mutable variables / SSA
construction <LangImpl7.html>`_
projects / oota-llvm.git / blobdiff