不错的资料：
LLVM+Clang+编译器+链接器--保值【进阶之路二】 - 掘金
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下载 llvm-cookbook example:
$ git clone https://github.com/elongbug/llvm-cookbook.git也可以参照llvm-projec中的官方代码，一样的差不多：
https://github.com/llvm/llvm-project/tree/main/llvm/examples/Kaleidoscope
开发环境：
从apt source 安装llvm、clang和lldb：
$ apt install llvm
$ apt install llvm-dev
$ apt install clang
$ apt install lldb$ cd llvm-cookbook/Chapter_2
$ make
$ ./toy example1运行效果：
事隔十个版本，llvm的接口如故，还是让人惊讶与当时接口定义的周到；
具体代码如下：
Makefile:
CC = clang++
SOURCE = ch2_toy.cpp
TARGET = toy$(TARGET) : $(SOURCE)$(CC) $(SOURCE) -o $(TARGET) -g -O3 `llvm-config --cxxflags --ldflags --system-libs --libs core mcjit native`clean :rm $(TARGET)ch2_toy.cpp:
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
#include <cctype>
#include <cstdio>
#include <map>
#include <string>
#include <vector>
using namespace llvm;enum Token_Type { EOF_TOKEN = 0, DEF_TOKEN, IDENTIFIER_TOKEN, NUMERIC_TOKEN };FILE *file;
static std::string Identifier_string;
static int Numeric_Val;static int get_token() {static int LastChar = ' ';while (isspace(LastChar))LastChar = fgetc(file);if (isalpha(LastChar)) {Identifier_string = LastChar;while (isalnum((LastChar = fgetc(file))))Identifier_string += LastChar;if (Identifier_string == "def")return DEF_TOKEN;return IDENTIFIER_TOKEN;}if (isdigit(LastChar)) {std::string NumStr;do {NumStr += LastChar;LastChar = fgetc(file);} while (isdigit(LastChar));Numeric_Val = strtod(NumStr.c_str(), 0);return NUMERIC_TOKEN;}if (LastChar == '#') {doLastChar = fgetc(file);while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');if (LastChar != EOF)return get_token();}if (LastChar == EOF)return EOF_TOKEN;int ThisChar = LastChar;LastChar = fgetc(file);return ThisChar;
}namespace {class BaseAST {
public:virtual ~BaseAST() {}virtual Value *Codegen() = 0;
};class NumericAST : public BaseAST {int numeric_val;public:NumericAST(int val) : numeric_val(val) {}virtual Value *Codegen();
};class VariableAST : public BaseAST {std::string Var_Name;public:VariableAST(const std::string &name) : Var_Name(name) {}virtual Value *Codegen();
};class BinaryAST : public BaseAST {std::string Bin_Operator;BaseAST *LHS, *RHS;public:BinaryAST(std::string op, BaseAST *lhs, BaseAST *rhs): Bin_Operator(op), LHS(lhs), RHS(rhs) {}virtual Value *Codegen();
};class FunctionCallAST : public BaseAST {std::string Function_Callee;std::vector<BaseAST *> Function_Arguments;public:FunctionCallAST(const std::string &callee, std::vector<BaseAST *> &args): Function_Callee(callee), Function_Arguments(args) {}virtual Value *Codegen();
};class FunctionDeclAST {std::string Func_Name;std::vector<std::string> Arguments;public:FunctionDeclAST(const std::string &name, const std::vector<std::string> &args): Func_Name(name), Arguments(args){};Function *Codegen();
};class FunctionDefnAST {FunctionDeclAST *Func_Decl;BaseAST *Body;public:FunctionDefnAST(FunctionDeclAST *proto, BaseAST *body): Func_Decl(proto), Body(body) {}Function *Codegen();
};
} // namespacestatic int Current_token;
static int next_token() { return Current_token = get_token(); }static std::map<char, int> Operator_Precedence;static int getBinOpPrecedence() {if (!isascii(Current_token))return -1;int TokPrec = Operator_Precedence[Current_token];if (TokPrec <= 0)return -1;return TokPrec;
}static BaseAST *expression_parser();static BaseAST *identifier_parser() {std::string IdName = Identifier_string;next_token();if (Current_token != '(')return new VariableAST(IdName);next_token();std::vector<BaseAST *> Args;if (Current_token != ')') {while (1) {BaseAST *Arg = expression_parser();if (!Arg)return 0;Args.push_back(Arg);if (Current_token == ')')break;if (Current_token != ',')return 0;next_token();}}next_token();return new FunctionCallAST(IdName, Args);
}static BaseAST *numeric_parser() {BaseAST *Result = new NumericAST(Numeric_Val);next_token();return Result;
}static BaseAST *paran_parser() {next_token();BaseAST *V = expression_parser();if (!V)return 0;if (Current_token != ')')return 0;return V;
}static BaseAST *Base_Parser() {switch (Current_token) {default:return 0;case IDENTIFIER_TOKEN:return identifier_parser();case NUMERIC_TOKEN:return numeric_parser();case '(':return paran_parser();}
}static BaseAST *binary_op_parser(int Old_Prec, BaseAST *LHS) {while (1) {int Operator_Prec = getBinOpPrecedence();if (Operator_Prec < Old_Prec)return LHS;int BinOp = Current_token;next_token();BaseAST *RHS = Base_Parser();if (!RHS)return 0;int Next_Prec = getBinOpPrecedence();if (Operator_Prec < Next_Prec) {RHS = binary_op_parser(Operator_Prec + 1, RHS);if (RHS == 0)return 0;}LHS = new BinaryAST(std::to_string(BinOp), LHS, RHS);}
}static BaseAST *expression_parser() {BaseAST *LHS = Base_Parser();if (!LHS)return 0;return binary_op_parser(0, LHS);
}static FunctionDeclAST *func_decl_parser() {if (Current_token != IDENTIFIER_TOKEN)return 0;std::string FnName = Identifier_string;next_token();if (Current_token != '(')return 0;std::vector<std::string> Function_Argument_Names;while (next_token() == IDENTIFIER_TOKEN)Function_Argument_Names.push_back(Identifier_string);if (Current_token != ')')return 0;next_token();return new FunctionDeclAST(FnName, Function_Argument_Names);
}static FunctionDefnAST *func_defn_parser() {next_token();FunctionDeclAST *Decl = func_decl_parser();if (Decl == 0)return 0;if (BaseAST *Body = expression_parser())return new FunctionDefnAST(Decl, Body);return 0;
}static FunctionDefnAST *top_level_parser() {if (BaseAST *E = expression_parser()) {FunctionDeclAST *Func_Decl =new FunctionDeclAST("", std::vector<std::string>());return new FunctionDefnAST(Func_Decl, E);}return 0;
}static void init_precedence() {Operator_Precedence['-'] = 1;Operator_Precedence['+'] = 2;Operator_Precedence['/'] = 3;Operator_Precedence['*'] = 4;
}static Module *Module_Ob;
static LLVMContext MyGlobalContext;
static IRBuilder<> Builder(MyGlobalContext);
static std::map<std::string, Value *> Named_Values;Value *NumericAST::Codegen() {return ConstantInt::get(Type::getInt32Ty(MyGlobalContext), numeric_val);
}Value *VariableAST::Codegen() {Value *V = Named_Values[Var_Name];return V ? V : 0;
}Value *BinaryAST::Codegen() {Value *L = LHS->Codegen();Value *R = RHS->Codegen();if (L == 0 || R == 0)return 0;switch (atoi(Bin_Operator.c_str())) {case '+':return Builder.CreateAdd(L, R, "addtmp");case '-':return Builder.CreateSub(L, R, "subtmp");case '*':return Builder.CreateMul(L, R, "multmp");case '/':return Builder.CreateUDiv(L, R, "divtmp");default:return 0;}
}Value *FunctionCallAST::Codegen() {Function *CalleeF = Module_Ob->getFunction(Function_Callee);std::vector<Value *> ArgsV;for (unsigned i = 0, e = Function_Arguments.size(); i != e; ++i) {ArgsV.push_back(Function_Arguments[i]->Codegen());if (ArgsV.back() == 0)return 0;}return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
}Function *FunctionDeclAST::Codegen() {std::vector<Type *> Integers(Arguments.size(),Type::getInt32Ty(MyGlobalContext));FunctionType *FT =FunctionType::get(Type::getInt32Ty(MyGlobalContext), Integers, false);Function *F =Function::Create(FT, Function::ExternalLinkage, Func_Name, Module_Ob);if (F->getName() != Func_Name) {F->eraseFromParent();F = Module_Ob->getFunction(Func_Name);if (!F->empty())return 0;if (F->arg_size() != Arguments.size())return 0;}unsigned Idx = 0;for (Function::arg_iterator Arg_It = F->arg_begin(); Idx != Arguments.size();++Arg_It, ++Idx) {Arg_It->setName(Arguments[Idx]);Named_Values[Arguments[Idx]] = Arg_It;}return F;
}Function *FunctionDefnAST::Codegen() {Named_Values.clear();Function *TheFunction = Func_Decl->Codegen();if (TheFunction == 0)return 0;BasicBlock *BB = BasicBlock::Create(MyGlobalContext, "entry", TheFunction);Builder.SetInsertPoint(BB);if (Value *RetVal = Body->Codegen()) {Builder.CreateRet(RetVal);verifyFunction(*TheFunction);return TheFunction;}TheFunction->eraseFromParent();return 0;
}static void HandleDefn() {if (FunctionDefnAST *F = func_defn_parser()) {if (Function *LF = F->Codegen()) {}} else {next_token();}
}static void HandleTopExpression() {if (FunctionDefnAST *F = top_level_parser()) {if (Function *LF = F->Codegen()) {}} else {next_token();}
}static void Driver() {while (1) {switch (Current_token) {case EOF_TOKEN:return;case ';':next_token();break;case DEF_TOKEN:HandleDefn();break;default:HandleTopExpression();break;}}
}extern "C" double putchard(double X) {putchar((char)X);return 0;
}int main(int argc, char *argv[]) {LLVMContext &Context = MyGlobalContext;init_precedence();file = fopen(argv[1], "r");if (file == 0) {printf("Could not open file\n");}next_token();Module_Ob = new Module("my compiler", Context);Driver();Module_Ob->print(llvm::outs(), nullptr);return 0;
}
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一，从源码编译 llvm
下载源码：
$ git clone https://github.com/llvm/llvm-project.git创建 对应 commit id分支：
$ cd llvm-project
$ git checkout 5b78868661f42a70fa30 -b 17.x.greater源码成功编译 llvm-project commit id：
~/ex/llvm-project$ git log -1commit 5b78868661f42a70fa3006b1db41f78a6178d596 (HEAD -> main)生成构建：
cmake -G "Unix Makefiles" ../llvm \
-DLLVM_ENABLE_PROJECTS=all \
-DLLVM_BUILD_EXAMPLES=ON \
-DLLVM_TARGETS_TO_BUILD="host" \
-DCMAKE_BUILD_TYPE=Release \
-DLLVM_ENABLE_ASSERTIONS=ON \
-DLLVM_ENABLE_RUNTIMES=all \
-DLLVM_BUILD_LLVM_DYLIB=ON \
-DCMAKE_INSTALL_PREFIX=../inst_clanglld_rtall_5b78868661make -j8（i9 9900k 8物理core 16logic core， 64GB mem， 64GB swap）
make install二，编译Chapter2 example
可行的 Makefile：
CC = /home/kleenelan/ex/cookbook_llvm/inst_clanglld_rtall_5b78868661/bin/clang++
SOURCE = ch2_toy.cpp
TARGET = toy$(TARGET) : $(SOURCE)$(CC) $(SOURCE) -o $(TARGET) -g `/home/kleenelan/ex/cookbook_llvm/inst_clanglld_rtall_5b78868661/bin/llvm-config --cxxflags --ldflags --system-libs --libs core mcjit native` -I/home/kleenelan/ex/cookbook_llvm/inst_clanglld_rtall_5b78868661/include/c++/v1 -I/home/kleenelan/ex/cookbook_llvm/inst_clanglld_rtall_5b78868661/include/x86_64-unknown-linux-gnu/c++/v1 -L/usr/lib/gcc/x86_64-linux-gnu/11/ -L/home/kleenelan/ex/cookbook_llvm/inst_clanglld_rtall_5b78868661/lib/x86_64-unknown-linux-gnu -lc++clean :rm $(TARGET)ch2_toy.cpp
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
#include <cctype>
#include <cstdio>
#include <map>
#include <string>
#include <vector>
using namespace llvm;enum Token_Type { EOF_TOKEN = 0, DEF_TOKEN, IDENTIFIER_TOKEN, NUMERIC_TOKEN };FILE *file;
static std::string Identifier_string;
static int Numeric_Val;static int get_token() {static int LastChar = ' ';while (isspace(LastChar))LastChar = fgetc(file);if (isalpha(LastChar)) {Identifier_string = LastChar;while (isalnum((LastChar = fgetc(file))))Identifier_string += LastChar;if (Identifier_string == "def")return DEF_TOKEN;return IDENTIFIER_TOKEN;}if (isdigit(LastChar)) {std::string NumStr;do {NumStr += LastChar;LastChar = fgetc(file);} while (isdigit(LastChar));Numeric_Val = strtod(NumStr.c_str(), 0);return NUMERIC_TOKEN;}if (LastChar == '#') {doLastChar = fgetc(file);while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');if (LastChar != EOF)return get_token();}if (LastChar == EOF)return EOF_TOKEN;int ThisChar = LastChar;LastChar = fgetc(file);return ThisChar;
}namespace {class BaseAST {
public:virtual ~BaseAST() {}virtual Value *Codegen() = 0;
};class NumericAST : public BaseAST {int numeric_val;public:NumericAST(int val) : numeric_val(val) {}virtual Value *Codegen();
};class VariableAST : public BaseAST {std::string Var_Name;public:VariableAST(const std::string &name) : Var_Name(name) {}virtual Value *Codegen();
};class BinaryAST : public BaseAST {std::string Bin_Operator;BaseAST *LHS, *RHS;public:BinaryAST(std::string op, BaseAST *lhs, BaseAST *rhs): Bin_Operator(op), LHS(lhs), RHS(rhs) {}virtual Value *Codegen();
};class FunctionCallAST : public BaseAST {std::string Function_Callee;std::vector<BaseAST *> Function_Arguments;public:FunctionCallAST(const std::string &callee, std::vector<BaseAST *> &args): Function_Callee(callee), Function_Arguments(args) {}virtual Value *Codegen();
};class FunctionDeclAST {std::string Func_Name;std::vector<std::string> Arguments;public:FunctionDeclAST(const std::string &name, const std::vector<std::string> &args): Func_Name(name), Arguments(args){};Function *Codegen();
};class FunctionDefnAST {FunctionDeclAST *Func_Decl;BaseAST *Body;public:FunctionDefnAST(FunctionDeclAST *proto, BaseAST *body): Func_Decl(proto), Body(body) {}Function *Codegen();
};
} // namespacestatic int Current_token;
static int next_token() { return Current_token = get_token(); }static std::map<char, int> Operator_Precedence;static int getBinOpPrecedence() {if (!isascii(Current_token))return -1;int TokPrec = Operator_Precedence[Current_token];if (TokPrec <= 0)return -1;return TokPrec;
}static BaseAST *expression_parser();static BaseAST *identifier_parser() {std::string IdName = Identifier_string;next_token();if (Current_token != '(')return new VariableAST(IdName);next_token();std::vector<BaseAST *> Args;if (Current_token != ')') {while (1) {BaseAST *Arg = expression_parser();if (!Arg)return 0;Args.push_back(Arg);if (Current_token == ')')break;if (Current_token != ',')return 0;next_token();}}next_token();return new FunctionCallAST(IdName, Args);
}static BaseAST *numeric_parser() {BaseAST *Result = new NumericAST(Numeric_Val);next_token();return Result;
}static BaseAST *paran_parser() {next_token();BaseAST *V = expression_parser();if (!V)return 0;if (Current_token != ')')return 0;return V;
}static BaseAST *Base_Parser() {switch (Current_token) {default:return 0;case IDENTIFIER_TOKEN:return identifier_parser();case NUMERIC_TOKEN:return numeric_parser();case '(':return paran_parser();}
}static BaseAST *binary_op_parser(int Old_Prec, BaseAST *LHS) {while (1) {int Operator_Prec = getBinOpPrecedence();if (Operator_Prec < Old_Prec)return LHS;int BinOp = Current_token;next_token();BaseAST *RHS = Base_Parser();if (!RHS)return 0;int Next_Prec = getBinOpPrecedence();if (Operator_Prec < Next_Prec) {RHS = binary_op_parser(Operator_Prec + 1, RHS);if (RHS == 0)return 0;}LHS = new BinaryAST(std::to_string(BinOp), LHS, RHS);}
}static BaseAST *expression_parser() {BaseAST *LHS = Base_Parser();if (!LHS)return 0;return binary_op_parser(0, LHS);
}static FunctionDeclAST *func_decl_parser() {if (Current_token != IDENTIFIER_TOKEN)return 0;std::string FnName = Identifier_string;next_token();if (Current_token != '(')return 0;std::vector<std::string> Function_Argument_Names;while (next_token() == IDENTIFIER_TOKEN)Function_Argument_Names.push_back(Identifier_string);if (Current_token != ')')return 0;next_token();return new FunctionDeclAST(FnName, Function_Argument_Names);
}static FunctionDefnAST *func_defn_parser() {next_token();FunctionDeclAST *Decl = func_decl_parser();if (Decl == 0)return 0;if (BaseAST *Body = expression_parser())return new FunctionDefnAST(Decl, Body);return 0;
}static FunctionDefnAST *top_level_parser() {if (BaseAST *E = expression_parser()) {FunctionDeclAST *Func_Decl =new FunctionDeclAST("", std::vector<std::string>());return new FunctionDefnAST(Func_Decl, E);}return 0;
}static void init_precedence() {Operator_Precedence['-'] = 1;Operator_Precedence['+'] = 2;Operator_Precedence['/'] = 3;Operator_Precedence['*'] = 4;
}static Module *Module_Ob;
static LLVMContext MyGlobalContext;
static IRBuilder<> Builder(MyGlobalContext);
static std::map<std::string, Value *> Named_Values;Value *NumericAST::Codegen() {return ConstantInt::get(Type::getInt32Ty(MyGlobalContext), numeric_val);
}Value *VariableAST::Codegen() {Value *V = Named_Values[Var_Name];return V ? V : 0;
}Value *BinaryAST::Codegen() {Value *L = LHS->Codegen();Value *R = RHS->Codegen();if (L == 0 || R == 0)return 0;switch (atoi(Bin_Operator.c_str())) {case '+':return Builder.CreateAdd(L, R, "addtmp");case '-':return Builder.CreateSub(L, R, "subtmp");case '*':return Builder.CreateMul(L, R, "multmp");case '/':return Builder.CreateUDiv(L, R, "divtmp");default:return 0;}
}Value *FunctionCallAST::Codegen() {Function *CalleeF = Module_Ob->getFunction(Function_Callee);std::vector<Value *> ArgsV;for (unsigned i = 0, e = Function_Arguments.size(); i != e; ++i) {ArgsV.push_back(Function_Arguments[i]->Codegen());if (ArgsV.back() == 0)return 0;}return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
}Function *FunctionDeclAST::Codegen() {std::vector<Type *> Integers(Arguments.size(),Type::getInt32Ty(MyGlobalContext));FunctionType *FT =FunctionType::get(Type::getInt32Ty(MyGlobalContext), Integers, false);Function *F =Function::Create(FT, Function::ExternalLinkage, Func_Name, Module_Ob);if (F->getName() != Func_Name) {F->eraseFromParent();F = Module_Ob->getFunction(Func_Name);if (!F->empty())return 0;if (F->arg_size() != Arguments.size())return 0;}unsigned Idx = 0;for (Function::arg_iterator Arg_It = F->arg_begin(); Idx != Arguments.size();++Arg_It, ++Idx) {Arg_It->setName(Arguments[Idx]);Named_Values[Arguments[Idx]] = Arg_It;}return F;
}Function *FunctionDefnAST::Codegen() {Named_Values.clear();Function *TheFunction = Func_Decl->Codegen();if (TheFunction == 0)return 0;BasicBlock *BB = BasicBlock::Create(MyGlobalContext, "entry", TheFunction);Builder.SetInsertPoint(BB);if (Value *RetVal = Body->Codegen()) {Builder.CreateRet(RetVal);verifyFunction(*TheFunction);return TheFunction;}TheFunction->eraseFromParent();return 0;
}static void HandleDefn() {if (FunctionDefnAST *F = func_defn_parser()) {if (Function *LF = F->Codegen()) {}} else {next_token();}
}static void HandleTopExpression() {if (FunctionDefnAST *F = top_level_parser()) {if (Function *LF = F->Codegen()) {}} else {next_token();}
}static void Driver() {while (1) {switch (Current_token) {case EOF_TOKEN:return;case ';':next_token();break;case DEF_TOKEN:HandleDefn();break;default:HandleTopExpression();break;}}
}extern "C" double putchard(double X) {putchar((char)X);return 0;
}int main(int argc, char *argv[]) {LLVMContext &Context = MyGlobalContext;init_precedence();file = fopen(argv[1], "r");if (file == 0) {printf("Could not open file\n");}next_token();Module_Ob = new Module("my compiler", Context);Driver();Module_Ob->print(llvm::outs(), nullptr);return 0;
}
$ make
