1. 前言
作为一位程序猿， 每个人都有自己的编码风格，看到别人的烂的代码，真的就是感觉“是可忍，大爷不能忍！”。因此一套正规的代码规范显得尤为重要。最近公司正好要做代码规范，正好趁此良机，研究了一番。好了，废话不多说，现在开始一步一步将Clang插件集成到Xcode中。
2. Clang & LLVM 简介
Clang是LLVM为前端提供的编译器，而LLVM是Apple在Mac OS上用于替代GCC工具集的编译器软件集合。Clang支持类C语言的语言，例如C、C++、Objective C。Clang的与众不同在于其模块化的设计，使其不仅实现编译器前端部分，并且包装成库的形式提供给上层应用。Xcode的编译依赖于Clang编译器，并且Clang支持自定义插件，所以说Xcode也支持这样的插件，所以下文主要讲述实现Clang插件的编写并在Xcode中使用。
3. 下载相关源代码及其工具
1）打开终端，
sudo mkdir llvm
sudo chown `whoami` llvm && cd llvm
export LLVM_HOME=`pwd`
git clone -b release_50 [email protected]:llvm-mirror/llvm.git llvm
git clone -b release_50 [email protected]:llvm-mirror/clang.git llvm/tools/clang
git clone -b release_50 [email protected]:llvm-mirror/clang-tools-extra.git llvm/tools/clang/tools/extra
git clone -b release_50 [email protected]:llvm-mirror/compiler-rt.git llvm/projects/compiler-rt
2）下载cmake
下载cmake（cmake下载链接）并且打开，
image
点击Tools->How to install For Command Line Use
image
选择其中一种方式在终端中使用，我使用的是第二种方式。成功之后，在终端输入cmake，若如图所示，则表示cmake安装成功
image
4.添加插件项目
cd到llvm/tools/clang/examples目录下，执行
touch CMakeLists.txt
touch CodeChecker.cpp
touch CodeChecker.exports
打开此目录下的CMakeLists.txt文件，添加
add_subdirectory(CodeChecker)
5.开发插件
在新添加的CodeChecker.cpp文件中， 添加如下代码（感谢杰嗒嗒的阿杰大神提供的插件源码）
#include
#include
#include
#include
#include
#include
#include
#include
#include "clang/Frontend/FrontendPluginRegistry.h"
#include "clang/Rewrite/Core/Rewriter.h"
#include "clang/AST/AST.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Sema/Sema.h"
using namespace clang;
using namespace std;
namespace
{
static vector split(const string &s, char delim)
{
vector elems;
stringstream ss;
ss.str(s);
string item;
while (getline(ss, item, delim)) {
elems.push_back(item);
}
return elems;
}
class CodeVisitor : public RecursiveASTVisitor
{
private:
CompilerInstance &Instance;
ASTContext *Context;
public:
void setASTContext (ASTContext &context)
{
this -> Context = &context;
}
private:
/**
判断是否为用户源码
@param decl 声明
@return true 为用户源码，false 非用户源码
*/
bool isUserSourceCode (Decl *decl)
{
string filename = Instance.getSourceManager().getFilename(decl->getSourceRange().getBegin()).str();
if (filename.empty())
return false;
//非XCode中的源码都认为是用户源码
if(filename.find("/Applications/Xcode.app/") == 0)
return false;
return true;
}
/**
检测类名是否存在小写开头
@param decl 类声明
*/
void checkClassNameForLowercaseName(ObjCInterfaceDecl *decl)
{
StringRef className = decl -> getName();
//类名称必须以大写字母开头
char c = className[0];
if (isLowercase(c))
{
//修正提示
std::string tempName = className;
tempName[0] = toUppercase(c);
StringRef replacement(tempName);
SourceLocation nameStart = decl->getLocation();
SourceLocation nameEnd = nameStart.getLocWithOffset(className.size() - 1);
FixItHint fixItHint = FixItHint::CreateReplacement(SourceRange(nameStart, nameEnd), replacement);
//报告警告
DiagnosticsEngine &D = Instance.getDiagnostics();
int diagID = D.getCustomDiagID(DiagnosticsEngine::Error, "Class name should not start with lowercase letter");
SourceLocation location = decl->getLocation();
D.Report(location, diagID).AddFixItHint(fixItHint);
}
}
/**
检测类名是否包含下划线
@param decl 类声明
*/
void checkClassNameForUnderscoreInName(ObjCInterfaceDecl *decl)
{
StringRef className = decl -> getName();
//类名不能包含下划线
size_t underscorePos = className.find('_');
if (underscorePos != StringRef::npos)
{
//修正提示
std::string tempName = className;
std::string::iterator end_pos = std::remove(tempName.begin(), tempName.end(), '_');
tempName.erase(end_pos, tempName.end());
StringRef replacement(tempName);
SourceLocation nameStart = decl->getLocation();
SourceLocation nameEnd = nameStart.getLocWithOffset(className.size() - 1);
FixItHint fixItHint = FixItHint::CreateReplacement(SourceRange(nameStart, nameEnd), replacement);
//报告错误
DiagnosticsEngine &diagEngine = Instance.getDiagnostics();
unsigned diagID = diagEngine.getCustomDiagID(DiagnosticsEngine::Error, "Class name with `_` forbidden");
SourceLocation location = decl->getLocation().getLocWithOffset(underscorePos);
diagEngine.Report(location, diagID).AddFixItHint(fixItHint);
}
}
/**
检测方法名是否存在大写开头
@param decl 方法声明
*/
void checkMethodNameForUppercaseName(ObjCMethodDecl *decl)
{
//检查名称的每部分，都不允许以大写字母开头
Selector sel = decl -> getSelector();
int selectorPartCount = decl -> getNumSelectorLocs();
for (int i = 0; i < selectorPartCount; i++)
{
StringRef selName = sel.getNameForSlot(i);
char c = selName[0];
if (isUppercase(c))
{
//修正提示
std::string tempName = selName;
tempName[0] = toLowercase(c);
StringRef replacement(tempName);
SourceLocation nameStart = decl -> getSelectorLoc(i);
SourceLocation nameEnd = nameStart.getLocWithOffset(selName.size() - 1);
FixItHint fixItHint = FixItHint::CreateReplacement(SourceRange(nameStart, nameEnd), replacement);
//报告警告
DiagnosticsEngine &D = Instance.getDiagnostics();
int diagID = D.getCustomDiagID(DiagnosticsEngine::Error, "Selector name should not start with uppercase letter");
SourceLocation location = decl->getLocation();
D.Report(location, diagID).AddFixItHint(fixItHint);
}
}
}
/**
检测方法中定义的参数名称是否存在大写开头
@param decl 方法声明
*/
void checkMethodParamsNameForUppercaseName(ObjCMethodDecl *decl)
{
for (ObjCMethodDecl::param_iterator it = decl -> param_begin(); it != decl -> param_end(); it++)
{
ParmVarDecl *parmVarDecl = *it;
StringRef name = parmVarDecl -> getName();
char c = name[0];
if (isUppercase(c))
{
//修正提示
std::string tempName = name;
tempName[0] = toLowercase(c);
StringRef replacement(tempName);
SourceLocation nameStart = parmVarDecl -> getLocation();
SourceLocation nameEnd = nameStart.getLocWithOffset(name.size() - 1);
FixItHint fixItHint = FixItHint::CreateReplacement(SourceRange(nameStart, nameEnd), replacement);
//报告警告
DiagnosticsEngine &D = Instance.getDiagnostics();
int diagID = D.getCustomDiagID(DiagnosticsEngine::Warning, "Selector's param name should not start with uppercase letter");
SourceLocation location = decl->getLocation();
D.Report(location, diagID).AddFixItHint(fixItHint);
}
}
}
/**
检测方法实现是否超过500行代码
@param decl 方法声明
*/
void checkMethodBodyForOver500Lines(ObjCMethodDecl *decl)
{
if (decl -> hasBody())
{
//存在方法体
Stmt *methodBody = decl -> getBody();
string srcCode;
srcCode.assign(Instance.getSourceManager().getCharacterData(methodBody->getSourceRange().getBegin()),
methodBody->getSourceRange().getEnd().getRawEncoding() - methodBody->getSourceRange().getBegin().getRawEncoding() + 1);
vector lines = split(srcCode, '\n');
if(lines.size() > 500)
{
DiagnosticsEngine &D = Instance.getDiagnostics();
unsigned diagID = D.getCustomDiagID(DiagnosticsEngine::Warning, "Single method should not have body over 500 lines");
D.Report(decl -> getSourceRange().getBegin(), diagID);
}
}
}
/**
检测属性名是否存在大写开头
@param decl 属性声明
*/
void checkPropertyNameForUppercaseName(ObjCPropertyDecl *decl)
{
bool checkUppercaseNameIndex = 0;
StringRef name = decl -> getName();
if (name.find('_') == 0)
{
//表示以下划线开头
checkUppercaseNameIndex = 1;
}
//名称必须以小写字母开头
char c = name[checkUppercaseNameIndex];
if (isUppercase(c))
{
//修正提示
std::string tempName = name;
tempName[checkUppercaseNameIndex] = toLowercase(c);
StringRef replacement(tempName);
SourceLocation nameStart = decl->getLocation();
SourceLocation nameEnd = nameStart.getLocWithOffset(name.size() - 1);
FixItHint fixItHint = FixItHint::CreateReplacement(SourceRange(nameStart, nameEnd), replacement);
//报告错误
DiagnosticsEngine &D = Instance.getDiagnostics();
int diagID = D.getCustomDiagID(DiagnosticsEngine::Error, "Property name should not start with uppercase letter");
SourceLocation location = decl->getLocation();
D.Report(location, diagID).AddFixItHint(fixItHint);
}
}
/**
检测属性名是否包含下划线
@param decl 属性声明
*/
void checkPropertyNameForUnderscoreInName(ObjCPropertyDecl *decl)
{
StringRef name = decl -> getName();
if (name.size() == 1)
{
//不需要检测
return;
}
//类名不能包含下划线
size_t underscorePos = name.find('_', 1);
if (underscorePos != StringRef::npos)
{
//修正提示
std::string tempName = name;
std::string::iterator end_pos = std::remove(tempName.begin() + 1, tempName.end(), '_');
tempName.erase(end_pos, tempName.end());
StringRef replacement(tempName);
SourceLocation nameStart = decl->getLocation();
SourceLocation nameEnd = nameStart.getLocWithOffset(name.size() - 1);
FixItHint fixItHint = FixItHint::CreateReplacement(SourceRange(nameStart, nameEnd), replacement);
//报告错误
DiagnosticsEngine &diagEngine = Instance.getDiagnostics();
unsigned diagID = diagEngine.getCustomDiagID(DiagnosticsEngine::Error, "Property name with `_` forbidden");
SourceLocation location = decl->getLocation().getLocWithOffset(underscorePos);
diagEngine.Report(location, diagID).AddFixItHint(fixItHint);
}
}
/**
检测委托属性是否有使用weak修饰
@param decl 属性声明
*/
void checkDelegatePropertyForUsageWeak (ObjCPropertyDecl *decl)
{
QualType type = decl -> getType();
StringRef typeStr = type.getAsString();
//Delegate
if(typeStr.find("<") != string::npos && typeStr.find(">") != string::npos)
{
ObjCPropertyDecl::PropertyAttributeKind attrKind = decl -> getPropertyAttributes();
string typeSrcCode;
typeSrcCode.assign(Instance.getSourceManager().getCharacterData(decl -> getSourceRange().getBegin()),
decl -> getSourceRange().getEnd().getRawEncoding() - decl -> getSourceRange().getBegin().getRawEncoding());
if(!(attrKind & ObjCPropertyDecl::OBJC_PR_weak))
{
DiagnosticsEngine &diagEngine = Instance.getDiagnostics();
unsigned diagID = diagEngine.getCustomDiagID(DiagnosticsEngine::Warning, "Delegate should be declared as weak.");
diagEngine.Report(decl -> getLocation(), diagID);
}
}
}
/**
检测常量名称是否存在小写开头
@param decl 常量声明
*/
void checkConstantNameForLowercaseName (VarDecl *decl)
{
StringRef className = decl -> getName();
//类名称必须以大写字母开头
char c = className[0];
if (isLowercase(c))
{
//修正提示
std::string tempName = className;
tempName[0] = toUppercase(c);
StringRef replacement(tempName);
SourceLocation nameStart = decl->getLocation();
SourceLocation nameEnd = nameStart.getLocWithOffset(className.size() - 1);
FixItHint fixItHint = FixItHint::CreateReplacement(SourceRange(nameStart, nameEnd), replacement);
//报告警告
DiagnosticsEngine &D = Instance.getDiagnostics();
int diagID = D.getCustomDiagID(DiagnosticsEngine::Warning, "Constant name should not start with lowercase letter");
SourceLocation location = decl->getLocation();
D.Report(location, diagID).AddFixItHint(fixItHint);
}
}
/**
检测变量名称是否存在大写开头
@param decl 变量声明
*/
void checkVarNameForUppercaseName (VarDecl *decl)
{
StringRef className = decl -> getName();
//类名称必须以大写字母开头
char c = className[0];
if (isUppercase(c))
{
//修正提示
std::string tempName = className;
tempName[0] = toLowercase(c);
StringRef replacement(tempName);
SourceLocation nameStart = decl->getLocation();
SourceLocation nameEnd = nameStart.getLocWithOffset(className.size() - 1);
FixItHint fixItHint = FixItHint::CreateReplacement(SourceRange(nameStart, nameEnd), replacement);
//报告警告
DiagnosticsEngine &D = Instance.getDiagnostics();
int diagID = D.getCustomDiagID(DiagnosticsEngine::Warning, "Variable name should not start with uppercase letter");
SourceLocation location = decl->getLocation();
D.Report(location, diagID).AddFixItHint(fixItHint);
}
}
/**
检测变量名称
@param decl 变量声明
*/
void checkVarName(VarDecl *decl)
{
if (decl -> isStaticLocal())
{
//静态变量
if (decl -> getType().isConstant(*this -> Context))
{
//常量
checkConstantNameForLowercaseName(decl);
}
else
{
//非常量
checkVarNameForUppercaseName(decl);
}
}
else if (decl -> isLocalVarDecl())
{
//本地变量
if (decl -> getType().isConstant(*this -> Context))
{
//常量
checkConstantNameForLowercaseName(decl);
}
else
{
//非常量
checkVarNameForUppercaseName(decl);
}
}
else if (decl -> isFileVarDecl())
{
//文件定义变量
if (decl -> getType().isConstant(*this -> Context))
{
//常量
checkConstantNameForLowercaseName(decl);
}
else
{
//非常量
checkVarNameForUppercaseName(decl);
}
}
}
public:
CodeVisitor (CompilerInstance &Instance)
:Instance(Instance)
{
}
/**
观察ObjC的类声明
@param declaration 声明对象
@return 返回
*/
bool VisitObjCInterfaceDecl(ObjCInterfaceDecl *declaration)
{
if (isUserSourceCode(declaration))
{
checkClassNameForLowercaseName(declaration);
checkClassNameForUnderscoreInName(declaration);
}
return true;
}
/**
观察类方法声明
@param declaration 声明对象
@return 返回
*/
bool VisitObjCMethodDecl(ObjCMethodDecl *declaration)
{
if (isUserSourceCode(declaration))
{
checkMethodNameForUppercaseName(declaration);
checkMethodParamsNameForUppercaseName(declaration);
checkMethodBodyForOver500Lines(declaration);
}
return true;
}
/**
观察类属性声明
@param declaration 声明对象
@return 返回
*/
bool VisitObjCPropertyDecl(ObjCPropertyDecl *declaration)
{
if (isUserSourceCode(declaration))
{
checkPropertyNameForUppercaseName(declaration);
checkPropertyNameForUnderscoreInName(declaration);
checkDelegatePropertyForUsageWeak(declaration);
}
return true;
}
/**
观察变量声明
@param declaration 声明对象
@return 返回
*/
bool VisitVarDecl(VarDecl *declaration)
{
if (isUserSourceCode(declaration))
{
checkVarName(declaration);
}
return true;
}
/**
观察枚举常量声明
@param declaration 声明对象
@return 返回
*/
// bool VisitEnumConstantDecl (EnumConstantDecl *declaration)
// {
// return true;
// }
};
class CodeConsumer : public ASTConsumer
{
CompilerInstance &Instance;
std::set ParsedTemplates;
public:
CodeConsumer(CompilerInstance &Instance,
std::set ParsedTemplates)
: Instance(Instance), ParsedTemplates(ParsedTemplates), visitor(Instance)
{
}
bool HandleTopLevelDecl(DeclGroupRef DG) override
{
return true;
}
void HandleTranslationUnit(ASTContext& context) override
{
visitor.setASTContext(context);
visitor.TraverseDecl(context.getTranslationUnitDecl());
}
private:
CodeVisitor visitor;
};
class CodeASTAction : public PluginASTAction
{
std::set ParsedTemplates;
protected:
std::unique_ptr CreateASTConsumer(CompilerInstance &CI,
llvm::StringRef) override
{
return llvm::make_unique(CI, ParsedTemplates);
}
bool ParseArgs(const CompilerInstance &CI,
const std::vector &args) override
{
// DiagnosticsEngine &D = CI.getDiagnostics();
// D.Report(D.getCustomDiagID(DiagnosticsEngine::Error,
// "My plugin Started..."));
return true;
}
};
}
static clang::FrontendPluginRegistry::Add
X("CodeChecker", "Code Checker");
6.使用cmake编译源代码
cd到llvm文件目录下，执行
mkdir llvm_build && cd llvm_build
cmake -G Xcode ../llvm -DCMAKE_BUILD_TYPE:STRING=MinSizeRel
编译执行之后，就会在llvm_build文件目录下，看到我们十分熟悉的LLVM.xcodeproj文件了。
7.通过Xcode编译，生成.dylib文件
使用Xcode打开LLVM.xcodeproj，
image.png
选择Automatically Create Schemes，
编译 clang，CodeChecker，libclang
image.png
成功后，在llvm_build/Debug/lib目录下如图所示
image.png
8.使用插件
要在Xcode中使用Clang插件，需要Hack Xcode.app, 下载链接为（Hack Xcode，密码为：bwue）
HackedClang.xcplugin显示包内容，进入到contents/Resources，打开HackedClang.xcspec
image.png
修改name，这里随意，自己能分辨就好。
修改ExecPath 为自己clang所在的目录。
执行：
sudo mv HackedClang.xcplugin `xcode-select -print-path`/../PlugIns/Xcode3Core.ideplugin/Contents/SharedSupport/Developer/Library/Xcode/Plug-ins
sudo mv HackedBuildSystem.xcspec `xcode-select -print-path`/Platforms/iPhoneSimulator.platform/Developer/Library/Xcode/Specifications
9. 配置Xcode
新建一个工程，进入到Build Setting
image.png
选择刚才设置的name，
在Other_flags下， 添加如下
image.png
10. 测试Clang插件
添加一个大写字母开头的属性
image.png
如果保存， 那么恭喜你，已经成功了。
11. 总结
代码规范的 规则都在CodeChecker.cpp中进行编写，编写执行后，使用cmake进行编译操作，接下来使用Xcode进行编译CodeChecker，生成最新CodeChecker.dylib包，就可以在别的项目中使用了。
鄙人C++能力有限，十分感谢谢杰嗒嗒的阿杰提供的规范代码。
推荐链接：
https://kangwang1988.github.io/tech/2016/10/31/write-your-first-clang-plugin.html
http://www.jianshu.com/p/581ef614a1c5
https://cmake.org/cmake-tutorial/
http://llvm.org/