这个很多人都做过，文章也挺多的，我也是参考别人文章的，不过直到真正实现还是踩了许多坑，所以记录下来，或许对其他人有帮助。其实LLVM和Clang我还没有好好研究过，之前大部分都是用Swift开发，代码风格检查都是用的Swiftlint，所以这次选择OC的代码检查作为开始，通过实践找找感觉和兴趣，之后再一点一点精进。
下载源码
代开终端
sudo mkdir llvm
sudo chown `whoami` llvm
cd llvm
export LLVM_HOME=`pwd`
git clone -b release_60 https://github.com/llvm-mirror/llvm.git llvm
git clone -b release_60 https://github.com/llvm-mirror/clang.git llvm/tools/clang
git clone -b release_60 https://github.com/llvm-mirror/clang-tools-extra.git llvm/tools/clang/tools/extra
git clone -b release_60 https://github.com/llvm-mirror/compiler-rt.git llvm/projects/compiler-rt
下载源码会比较慢，另外网上有其他文章，有的文章比较老，版本也比较老，建议用最新的release_60。
安装cmake
如果没有安装cmake需要安装一下，后面需要用。
brew update
brew install cmake
开始编写插件
cd到llvm/llvm/tools/clang/examples
1.打开这个目录下的CMakeLists.txt文件，然后添加add_subdirectory(CodeChecker)
Screen Shot 2019-05-20 at 10.40.00 PM.png
2.在当前目录创建新的文件夹CodeChecker，并cd到CodeChecker
mkdir CodeChecker
cd CodeChecker
3.在新建的CodeChecker目录下创建三个文件
touch CMakeLists.txt
touch CodeChecker.cpp
touch CodeChecker.exports
Screen Shot 2019-05-20 at 10.59.22 PM.png
在新创建的CMakeLists.txt中添加
if( NOT MSVC ) # MSVC mangles symbols differently
if( NOT LLVM_REQUIRES_RTTI )
if( NOT LLVM_REQUIRES_EH )
set(LLVM_EXPORTED_SYMBOL_FILE ${CMAKE_CURRENT_SOURCE_DIR}/CodeChecker.exports)
endif()
endif()
endif()
add_llvm_loadable_module(CodeChecker CodeChecker.cpp)
if(LLVM_ENABLE_PLUGINS AND (WIN32 OR CYGWIN))
target_link_libraries(CodeChecker ${cmake_2_8_12_PRIVATE}
clangAST
clangBasic
clangFrontend
LLVMSupport
)
endif()
在CodeChecker.cpp文件中加入
#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");
使用cmake编译源代码
1.cd到llvm，注意不是llvm/llvm，执行
mkdir llvm_build && cd llvm_build
cmake -G Xcode ../llvm -DCMAKE_BUILD_TYPE:STRING=MinSizeRel
2.然后会在llvm_build文件目录中看到LLVM.xcodeproj，用xcode打开，选择Automatically Create Schemes
Screen Shot 2019-05-20 at 11.01.35 PM.png
3.编译 clang，CodeChecker，libclang
Screen Shot 2019-05-20 at 11.07.04 PM.png
Screen Shot 2019-05-20 at 11.04.24 PM.png
Screen Shot 2019-05-20 at 11.04.49 PM.png
4.在llvm_build/Debug/lib目录下可以找到我们的插件，如下图：
Screen Shot 2019-05-20 at 11.09.41 PM.png
Xcode集成Plugin
创建需要加载插件的项目，在Build Settings栏目中的OTHER_CFLAGS添加上如下内容：
-Xclang -load -Xclang (.dylib)动态库路径 -Xclang -add-plugin -Xclang 插件名字
我把插件拷贝的桌面了，所以我的是：
-Xclang -load -Xclang /Users/roy.cao/Desktop/CodeChecker.dylib -Xclang -add-plugin -Xclang CodeChecker
Screen Shot 2019-05-20 at 11.45.39 PM.png
然后你build项目，可能有unable to load plugin '/Users/roy.cao/Desktop/CodeChecker.dylib'的error，这是由于Clang插件需要对应的Clang版本来加载，如果版本不一致会导致编译错误。
Screen Shot 2019-05-20 at 11.28.02 PM.png
在Build Settings栏目中新增两项用户定义的设置，分别为CC和CXX
CC对应的是自己编译的clang的绝对路径，CXX对应的是自己编译的clang++的绝对路径
Screen Shot 2019-05-20 at 11.31.47 PM.png
/Users/roy.cao/llvm/llvm_build/Debug/bin/clang
/Users/roy.cao/llvm/llvm_build/Debug/bin/clang++
再build，会有以下错误：
Screen Shot 2019-05-20 at 11.37.39 PM.png
在Build Settings栏目中搜索index，将Enable Index-Wihle-Building Functionality的Default改为NO.
Screen Shot 2019-05-20 at 11.39.40 PM.png
再build可能会出现一大堆系统库的 symbol not found 错误
Screen Shot 2019-05-20 at 11.41.49 PM.png
这个时候需要在刚刚OTHER_CFLAGS的
-Xclang -load -Xclang /Users/roy.cao/Desktop/CodeChecker.dylib -Xclang -add-plugin -Xclang CodeChecker
后面再加上-isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator12.0.sdk
注意iPhoneSimulator12.0.sdk，每个人的可能不同，需要到目录下看看自己的版本。
那么完整的就是下图这样：
Screen Shot 2019-05-20 at 11.54.47 PM.png
再build就能做代码风格检查啦，庆祝一下吧~~~~
Screen Shot 2019-05-20 at 11.52.35 PM.png
参考文章：
LLVM & Clang 入门
使用Xcode开发iOS语法检查的Clang插件
Clang 之旅--使用 Xcode 开发 Clang 插件