二，构建Clang libTooling 工具-CSDN博客

Windows 下构建自己的 Clang libTooling 工具

[Windows 下构建自己的 Clang libTooling 工具](#Windows 下构建自己的 Clang libTooling 工具 "#windows-%E4%B8%8B%E6%9E%84%E5%BB%BA%E8%87%AA%E5%B7%B1%E7%9A%84-clang-libtooling-%E5%B7%A5%E5%85%B7")
- [什么是 Clang libTooling 工具](#什么是 Clang libTooling 工具 "#%E4%BB%80%E4%B9%88%E6%98%AF-clang-libtooling-%E5%B7%A5%E5%85%B7")
- [It's time up](#It’s time up "#its-time-up")
  - 构建一个代码解析工具
  - 将工具集成到你的工程中
  - [使用 clang-cl 为前端](#使用 clang-cl 为前端 "#%E4%BD%BF%E7%94%A8-clang-cl-%E4%B8%BA%E5%89%8D%E7%AB%AF")
- 以源码的方式集成到项目中
- End

什么是 Clang libTooling 工具

Clang 我想会看这篇文章的人应该都不会完全陌生，现在 Clang 不仅仅是一个编译器的前端，我们可以通过一些方法使用 Clang 强大的源码解析、检查等功能。如果想要详细了解点这里的官方文档和大佬的BLOG：
1. libclang : 它还可以作为一个功能库提供一些用于源码解析 AST 的稳定高级 C 语言抽象接口。
2. clang libTooling : C++ 接口，旨在编写独立工具，以及集成到运行 clang 工具的服务中。
3. clang plugin : Clang 插件允许您在 AST 上添加运行其他操作作为编译的一部分。插件是由编译器在运行时加载的动态库，它们很容易集成到构建环境中。

It's time up

本文主要介绍如何通过 llvm 工程构建属于自己的 Clang Tooling 工具。主要分为两个部分：
1. 通过 llvm 工程构建一个可以提供自己需要的功能工具。
2. 如何将该工具以模块的形式集成到自己的工程中。
3. 直接通过源码在自己的工程中进行编译。

构建一个代码解析工具

其实参考这篇文档描述的很详细了，如果你已经正确通过源码搭建了 LLVM 环境，那么操作起来是非常简单的。

首先，在 clang/tools/ 目录下新加一个自己需要的工具目录，这里以 QtPlugin 为例，然后添加自己的源文件以及 CmakeLists.txt。
修改父目录下的 CMakeLists.txt 添加刚刚创建的 QtPlugin 目录。

接下来编写自己想要的功能代码，然后创建编写 QtPlugin 目录下的 CmakeLists.txt 参考着同一级目录中其他 tools 来就行。

sh 复制代码

set(LLVM_LINK_COMPONENTS
Support
)

add_clang_executable(QTPluginTooling
    QtPlugin.cpp
)

clang_target_link_libraries(QTPluginTooling
    PRIVATE
    clangAST
    clangBasic
    clangDriver
    clangFormat
    clangLex
    clangParse
    clangSema
    clangFrontend
    clangTooling
    clangToolingCore
    clangRewrite
    clangRewriteFrontend
)

接下来确保你的 CMakeTools 参数配置项 clang 模块处于 enable 状态(详情参见配置 LLVM环境配置)，通过点击生成，CMakeTools 工具直接编译生成即可。最终可以在 build/bin 目录下找到你刚刚生成的工具。

将工具集成到你的工程中

Emmmm... 可能你觉得生成个可执行得工具并不满足，想要让 clang 强大得功能在自己项目中更加紧密的使用，那么你可以直接集成 clang 已经提供的 libTooling 等功能库，甚至自己生成定制的功能模块，以库得形式提供功能到你的项目中。

这里有一个很棒的 github 项目关于 LLVM-clang 的使用示例，可惜的是由于 LLVM-clang 发展的迅速，C++ 接口并不稳定，10.0.0版本的程序可能在下一版本编译都会失败掉，因此本小节会选取一个简单的示例，可以在 10.0.0 下编译通过，生成功能库后集成到自己的项目中。

还记得上一节中的 clang 文件夹么，我们在其中编写了程序以及 CmakeLists.txt 最终生成了可以执行的小工具。而这一节我们的目的是生成一个库，这里我是将工具源码目录放到了与 clang 同级的目录下，可以找到一个 clang-tool-extra 文件夹内，可以发现这个目录下就是一些 clang 提供得扩展功能库，因此我们首先需要在这个目录下创建一个自己得工具文件夹，并如图中一样创建需要的源文件以及 CmakeLists.txt 。

为 LoopConvert.cpp 和 LoopConvert.h 添加源代码，参考的源代码，这里由于我们的目标是生成一个库，因此将 main 函数变成一个 C 接口功能函数，以及将功能类得定义抽出到 .h 头文件中，方便我们自己的项目调用相应得功能。llvm-clang-samples 项目中的源代码有一些接口兼容性的错误已经修复，下边是源码：

cpp 复制代码

//------------------------------------------------------------------------------
//  LoopConvert.h
//------------------------------------------------------------------------------
#include <clang/Frontend/FrontendActions.h>
#include <clang/Rewrite/Core/Rewriter.h>

namespace clang {
// For each source file provided to the tool, a new FrontendAction is created.
class MyFrontendAction : public ASTFrontendAction {
public:
MyFrontendAction() {}
void EndSourceFileAction() override;

std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
                                                StringRef file) override;

private:
Rewriter TheRewriter;
};
} // namespace clang

int Function(int argc, const char **argv);

cpp 复制代码

//------------------------------------------------------------------------------
//  LoopConvert.cpp
//------------------------------------------------------------------------------
// Tooling sample. Demonstrates:
//
// * How to write a simple source tool using libTooling.
// * How to use RecursiveASTVisitor to find interesting AST nodes.
// * How to use the Rewriter API to rewrite the source code.
//
// Eli Bendersky (eliben@gmail.com)
// This code is in the public domain
//------------------------------------------------------------------------------
#include <sstream>
#include <string>

#include "clang/AST/AST.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/Frontend/ASTConsumers.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Tooling/CommonOptionsParser.h"
#include "clang/Tooling/Tooling.h"
#include "llvm/Support/raw_ostream.h"
#include <llvm\ADT\STLExtras.h>

#include "LoopConvert.h"

using namespace clang;
using namespace clang::driver;
using namespace clang::tooling;

static llvm::cl::OptionCategory ToolingSampleCategory("Tooling Sample");

// By implementing RecursiveASTVisitor, we can specify which AST nodes
// we're interested in by overriding relevant methods.
class MyASTVisitor : public RecursiveASTVisitor<MyASTVisitor> {
public:
MyASTVisitor(Rewriter &R) : TheRewriter(R) {}

bool VisitStmt(Stmt *s) {
    // Only care about If statements.
    if (isa<IfStmt>(s)) {
    IfStmt *IfStatement = cast<IfStmt>(s);
    Stmt *Then = IfStatement->getThen();

    TheRewriter.InsertText(Then->getBeginLoc(), "// the 'if' part\n", true,
                            true);

    Stmt *Else = IfStatement->getElse();
    if (Else)
        TheRewriter.InsertText(Else->getBeginLoc(), "// the 'else' part\n",
                            true, true);
    }

    return true;
}

bool VisitFunctionDecl(FunctionDecl *f) {
    // Only function definitions (with bodies), not declarations.
    if (f->hasBody()) {
    Stmt *FuncBody = f->getBody();

    // Type name as string
    QualType QT = f->getReturnType();
    std::string TypeStr = QT.getAsString();

    // Function name
    DeclarationName DeclName = f->getNameInfo().getName();
    std::string FuncName = DeclName.getAsString();

    // Add comment before
    std::stringstream SSBefore;
    SSBefore << "// Begin function " << FuncName << " returning " << TypeStr
            << "\n";
    SourceLocation ST = f->getSourceRange().getBegin();
    TheRewriter.InsertText(ST, SSBefore.str(), true, true);

    // And after
    std::stringstream SSAfter;
    SSAfter << "\n// End function " << FuncName;
    ST = FuncBody->getEndLoc().getLocWithOffset(1);
    TheRewriter.InsertText(ST, SSAfter.str(), true, true);
    }

    return true;
}

private:
Rewriter &TheRewriter;
};

// Implementation of the ASTConsumer interface for reading an AST produced
// by the Clang parser.
class MyASTConsumer : public ASTConsumer {
public:
MyASTConsumer(Rewriter &R) : Visitor(R) {}

// Override the method that gets called for each parsed top-level
// declaration.
bool HandleTopLevelDecl(DeclGroupRef DR) override {
    for (DeclGroupRef::iterator b = DR.begin(), e = DR.end(); b != e; ++b) {
    // Traverse the declaration using our AST visitor.
    Visitor.TraverseDecl(*b);
    (*b)->dump();
    }
    return true;
}

private:
MyASTVisitor Visitor;
};

std::unique_ptr<ASTConsumer>
MyFrontendAction::CreateASTConsumer(CompilerInstance &CI, StringRef file) {
    llvm::errs() << "** Creating AST consumer for: " << file << "\n";
    TheRewriter.setSourceMgr(CI.getSourceManager(), CI.getLangOpts());
    return std::make_unique<MyASTConsumer>(TheRewriter);
}
void MyFrontendAction::EndSourceFileAction() {
    SourceManager &SM = TheRewriter.getSourceMgr();
    llvm::errs() << "** EndSourceFileAction for: "
                << SM.getFileEntryForID(SM.getMainFileID())->getName() << "\n";

    // Now emit the rewritten buffer.
    TheRewriter.getEditBuffer(SM.getMainFileID()).write(llvm::outs());
}

int Function(int argc, const char **argv) {
    CommonOptionsParser op(argc, argv, ToolingSampleCategory);
    ClangTool Tool(op.getCompilations(), op.getSourcePathList());

    // ClangTool::run accepts a FrontendActionFactory, which is then used to
    // create new objects implementing the FrontendAction interface. Here we use
    // the helper newFrontendActionFactory to create a default factory that will
    // return a new MyFrontendAction object every time.
    // To further customize this, we could create our own factory class.
    return Tool.run(newFrontendActionFactory<MyFrontendAction>().get());
}

编写 CmakeLists.txt ，这部分参考其他目录下的工具编写即可：

sh 复制代码

set(LLVM_LINK_COMPONENTS
Support
)

add_clang_library(LoopConvertTooling
    LoopConvert.cpp

    LINK_LIBS
    clangAST
    clangBasic
    clangDriver
    clangFormat
    clangLex
    clangParse
    clangSema
    clangFrontend
    clangTooling
    clangToolingCore
    clangRewrite
    clangRewriteFrontend
)

在 clang-tools-extra 目录下的 CmakeLists.txt 下添加我们新增工具的目录。add_subdirectory(LoopConvert)。

一切准备就绪，确保 clang-tools-extra 编译指令是 enable ，点击 CmakeTools 的生成按钮即可，最终即可在 build/lib 目录下生成我们定制的的功能库，即 LoopConvertTooling.lib：

sh 复制代码

[main] 正在生成文件夹: llvm-project-10.0.0
[build] 正在启动生成
[proc] 执行命令: "F:\Visual Studio\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin\cmake.EXE" --build f:/LLVM10/llvm-project-10.0.0/build --config Release --target all -- -j 14
[build] [1/2  50% :: 16.844] Building CXX object tools\clang\tools\extra\LoopConvert\CMakeFiles\obj.LoopConvertTooling.dir\LoopConvert.cpp.obj
[build] [2/2 100% :: 17.265] Linking CXX static library lib\LoopConvertTooling.lib
[build] 生成已完成，退出代码为 0

接下来就是如何将我们生成的 LoopConvertTooling 库集成到我们自己的项目中去玩耍了，首先举个栗子，下边是我的测试代码，简单的调用了测试用的 C 接口：

cpp 复制代码

//------------------------------------------------------------------------------
//  main.cpp
//------------------------------------------------------------------------------
#include "LoopConvert.h"
#include "spdlog/spdlog.h"

int main(int argc, const char *argv[])
{
    if ((argc > 3) || (argc < 2))
    {
        spdlog::info("You input wrong number arguments!\n");
        return -1;
    }

    FILE *result = fopen(argv[1], "r");
    if (result == NULL)
    {
        spdlog::info("Can't open the file: {}.\n", argv[1]);
        return -1;
    }

    return Function(argc, argv);
}

首先要确保有环境变量或者指定路径可以找到我们刚才生成的 LoopConvertTooling 库和 LoopConvert.h 头文件。如图我将其拷到了我的工程目录下。
接下来是编写用于编译&链接相关功能库的 CMakeLists.txt 文件。find_package 用于会在 CMAKE_PREFIX_PATH 环境变量路径中查找相应的库文件。link_directories 与 include_directories 会自动在指定的路径中查找头文件和库。
sh 复制代码
```
find_package(LLVM REQUIRED CONFIG)
find_package(Clang REQUIRED CONFIG)

#指定连结库的路径
link_directories(${CLANG_LIB_PATH} ./Lib)
#指定头文件查找路径
include_directories(Include ${CLANG_INCLUDE_PATH})
```

最终在 target_link_libraries 中链接如下的库。 ${LLVMSupport} 与 ${clangxxx} 这些都要在成功 find_package 后才能正确使用：

sh 复制代码

target_link_libraries(${PROJECT_NAME} PRIVATE

${linkLib}
LoopConvertTooling

${clangAST}
${clangBasic}
${clangDriver}
${clangFormat}
${clangLex}
${clangParse}
${clangSema}
${clangFrontend}
${clangTooling}
${clangToolingCore}
${clangRewrite}
${clangRewriteFrontend}

${LLVMSupport}
)

最终编译我们的项目，注意这里使用的时 clang-cl 为前端，如果直接使用 cl.exe 编译的话会有大量 warning 警告，原因是 clang 与 msvc-cl 有一些基础变量定义不同造成：

sh 复制代码

[cms-client] 正在使用"Ninja"CMake 生成器进行配置
[cms-client] 正在使用"Ninja"CMake 生成器进行配置
[cmake] The CXX compiler identification is Clang 10.0.0
[cmake] Check for working CXX compiler: F:/LLVM10/Lib/bin/clang-cl.exe
[cmake] Check for working CXX compiler: F:/LLVM10/Lib/bin/clang-cl.exe -- works
[cmake] Detecting CXX compiler ABI info
[cmake] Detecting CXX compiler ABI info - done
[cmake] Detecting CXX compile features
[cmake] Detecting CXX compile features - done
[cmake] Looking for C++ include pthread.h
[cmake] Looking for C++ include pthread.h - not found
[cmake] Found Threads: TRUE  
[cmake] Configuring done
[cmake] Generating done
[build] 正在启动生成
[proc] 执行命令: "F:\Visual Studio\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin\cmake.EXE" --build f:/WorkSpace/AutoTestProject/AUTestTools/build --config Release --target all -- -j 14
[build] [2/15   6% :: 0.103] Automatic MOC and UIC for target ProjectUnitTest
[build] [2/13  15% :: 0.275] Automatic MOC and UIC for target Automated_UnitTest
[build] [12/13  23% :: 0.377] Building CXX object CMakeFiles\Automated_UnitTest.dir\Src\test.cpp.obj
[build] [12/13  30% :: 0.401] Building CXX object CMakeFiles\Automated_UnitTest.dir\qrc_image.cpp.obj
[build] [12/13  38% :: 2.254] Building CXX object CMakeFiles\Automated_UnitTest.dir\Src\window\DiagramWindow\Arrow.cpp.obj
[build] [12/13  46% :: 2.352] Building CXX object CMakeFiles\Automated_UnitTest.dir\Automated_UnitTest_autogen\mocs_compilation.cpp.obj
[build] [12/13  53% :: 4.049] Building CXX object CMakeFiles\Automated_UnitTest.dir\Src\window\DiagramWindow\DiagramTextItem.cpp.obj
[build] [12/13  61% :: 4.158] Building CXX object CMakeFiles\Automated_UnitTest.dir\Src\main.cpp.obj
[build] [12/13  69% :: 4.235] Building CXX object CMakeFiles\Automated_UnitTest.dir\Src\window\DiagramWindow\DiagramScene.cpp.obj
[build] [12/13  76% :: 4.295] Building CXX object CMakeFiles\Automated_UnitTest.dir\Src\window\DiagramWindow\DiagramItem.cpp.obj
[build] [12/13  84% :: 5.678] Building CXX object CMakeFiles\Automated_UnitTest.dir\Src\window\mainwindow.cpp.obj
[build] [12/13  92% :: 6.419] Building CXX object CMakeFiles\Automated_UnitTest.dir\Src\window\DiagramWindow\DiagramSceneWindow.cpp.obj
[build] [13/13 100% :: 6.760] Linking CXX executable Automated_UnitTest.exe
[build] 生成已完成，退出代码为 0

执行一下生成的 .exe 程序：

cpp 复制代码

//测试用的输入文件 test.cpp
enum class Cpp11Enum
{
    RED = 10,
    BLUE = 20
};

struct Wowza
{
    virtual ~Wowza() = default;
    virtual void foo(int i = 0) = 0;
};

struct Badabang : Wowza
{
    void foo(int) override;

    bool operator==(const Badabang &o) const;
};

void testif_else()
{
    if (1)
    {
        int a = 10;
    }
    else if (2)
    {
        int b = 20;
    }
    else
    {
        int c = 20;
    }
}
template <typename T>
void bar(T &&t);

sh 复制代码

F:\WorkSpace\AutoTestProject\AUTestTools>"F:\WorkSpace\AutoTestProject\AUTestTools\build\test\ProjectUnitTest.exe" ./Src/test.cpp
Error while trying to load a compilation database:
Could not auto-detect compilation database for file "./Src/test.cpp"
No compilation database found in F:\WorkSpace\AutoTestProject\AUTestTools\Src or any parent directory
fixed-compilation-database: Error while opening fixed database: no such file or directory
json-compilation-database: Error while opening JSON database: no such file or directory
Running without flags.
** Creating AST consumer for: F:\WorkSpace\AutoTestProject\AUTestTools\Src\test.cpp
EnumDecl 0x1a5b6119e60 <F:\WorkSpace\AutoTestProject\AUTestTools\Src\test.cpp:1:1, line:5:1> line:1:12 class Cpp11Enum 'int'
|-EnumConstantDecl 0x1a5b6119f68 <line:3:5, col:11> col:5 RED 'Cpp11Enum'
| `-ConstantExpr 0x1a5b6119f48 <col:11> 'int' Int: 10
|   `-IntegerLiteral 0x1a5b6119f20 <col:11> 'int' 10
`-EnumConstantDecl 0x1a5b611a008 <line:4:5, col:12> col:5 BLUE 'Cpp11Enum'
`-ConstantExpr 0x1a5b6119fe8 <col:12> 'int' Int: 20
    `-IntegerLiteral 0x1a5b6119fc0 <col:12> 'int' 20
CXXRecordDecl 0x1a5b611a060 <F:\WorkSpace\AutoTestProject\AUTestTools\Src\test.cpp:7:1, line:11:1> line:7:8 struct Wowza definition
|-DefinitionData polymorphic abstract has_constexpr_non_copy_move_ctor can_const_default_init
| |-DefaultConstructor exists non_trivial constexpr needs_implicit defaulted_is_constexpr
| |-CopyConstructor simple non_trivial has_const_param needs_implicit implicit_has_const_param
| |-MoveConstructor
| |-CopyAssignment non_trivial has_const_param implicit_has_const_param
| |-MoveAssignment
| `-Destructor non_trivial user_declared
|-CXXRecordDecl 0x1a5b611a178 <col:1, col:8> col:8 implicit referenced struct Wowza
|-CXXDestructorDecl 0x1a5b611a2a8 <line:9:5, col:30> col:13 ~Wowza 'void ()' virtual default noexcept-unevaluated 0x1a5b611a2a8
|-CXXMethodDecl 0x1a5b611a468 <line:10:5, col:35> col:18 foo 'void (int)' virtual pure
| `-ParmVarDecl 0x1a5b611a3a8 <col:22, col:30> col:26 i 'int' cinit
|   `-IntegerLiteral 0x1a5b611ad40 <col:30> 'int' 0
`-CXXMethodDecl 0x1a5b611a568 <line:7:8> col:8 implicit operator= 'Wowza &(const Wowza &)' inline default noexcept-unevaluated 0x1a5b611a568
`-ParmVarDecl 0x1a5b611a678 <col:8> col:8 'const Wowza &'
CXXRecordDecl 0x1a5b611ad68 <F:\WorkSpace\AutoTestProject\AUTestTools\Src\test.cpp:13:1, line:18:1> line:13:8 struct Badabang definition
|-DefinitionData polymorphic has_constexpr_non_copy_move_ctor can_const_default_init
| |-DefaultConstructor exists non_trivial constexpr needs_implicit defaulted_is_constexpr
| |-CopyConstructor simple non_trivial has_const_param needs_overload_resolution implicit_has_const_param
| |-MoveConstructor exists simple non_trivial needs_overload_resolution
| |-CopyAssignment non_trivial has_const_param implicit_has_const_param
| |-MoveAssignment exists simple non_trivial needs_overload_resolution
| `-Destructor simple non_trivial needs_overload_resolution
|-public 'Wowza'
|-CXXRecordDecl 0x1a5b611af18 <col:1, col:8> col:8 implicit referenced struct Badabang
|-CXXMethodDecl 0x1a5b611b080 <line:15:5, col:19> col:10 foo 'void (int)'
| |-Overrides: [ 0x1a5b611a468 Wowza::foo 'void (int)' ]
| |-ParmVarDecl 0x1a5b611afc0 <col:14> col:17 'int'
| `-OverrideAttr 0x1a5b611b128 <col:19>
|-CXXMethodDecl 0x1a5b611b2a8 <line:17:5, col:40> col:10 operator== 'bool (const Badabang &) const'
| `-ParmVarDecl 0x1a5b611b1b8 <col:21, col:37> col:37 o 'const Badabang &'
|-CXXConstructorDecl 0x1a5b611b500 <line:13:8> col:8 implicit constexpr Badabang 'void (const Badabang &)' inline default noexcept-unevaluated 0x1a5b611b500
| `-ParmVarDecl 0x1a5b611b618 <col:8> col:8 'const Badabang &'
|-CXXConstructorDecl 0x1a5b611b6b8 <col:8> col:8 implicit constexpr Badabang 'void (Badabang &&)' inline default noexcept-unevaluated 0x1a5b611b6b8
| `-ParmVarDecl 0x1a5b611b7c8 <col:8> col:8 'Badabang &&'
|-CXXMethodDecl 0x1a5b611b868 <col:8> col:8 implicit operator= 'Badabang &(const Badabang &)' inline default noexcept-unevaluated 0x1a5b611b868
| `-ParmVarDecl 0x1a5b611b978 <col:8> col:8 'const Badabang &'
|-CXXMethodDecl 0x1a5b611b9e8 <col:8> col:8 implicit operator= 'Badabang &(Badabang &&)' inline default noexcept-unevaluated 0x1a5b611b9e8
| `-ParmVarDecl 0x1a5b611baf8 <col:8> col:8 'Badabang &&'
`-CXXDestructorDecl 0x1a5b611bb80 <col:8> col:8 implicit ~Badabang 'void () noexcept' inline default
`-Overrides: [ 0x1a5b611a2a8 Wowza::~Wowza 'void () noexcept' ]
FunctionDecl 0x1a5b611bca8 <F:\WorkSpace\AutoTestProject\AUTestTools\Src\test.cpp:20:1, line:34:1> line:20:6 testif_else 'void ()'
`-CompoundStmt 0x1a5b611d128 <line:21:1, line:34:1>
`-IfStmt 0x1a5b611d100 <line:22:5, line:33:5> has_else
    |-ImplicitCastExpr 0x1a5b611bdb8 <line:22:9> 'bool' <IntegralToBoolean>
    | `-IntegerLiteral 0x1a5b611bd90 <col:9> 'int' 1
    |-CompoundStmt 0x1a5b611ced0 <line:23:5, line:25:5>
    | `-DeclStmt 0x1a5b611ceb8 <line:24:9, col:19>
    |   `-VarDecl 0x1a5b611bde8 <col:9, col:17> col:13 a 'int' cinit
    |     `-IntegerLiteral 0x1a5b611ce90 <col:17> 'int' 10
    `-IfStmt 0x1a5b611d0d8 <line:26:10, line:33:5> has_else
    |-ImplicitCastExpr 0x1a5b611cf10 <line:26:14> 'bool' <IntegralToBoolean>
    | `-IntegerLiteral 0x1a5b611cee8 <col:14> 'int' 2
    |-CompoundStmt 0x1a5b611cfe8 <line:27:5, line:29:5>
    | `-DeclStmt 0x1a5b611cfd0 <line:28:9, col:19>
    |   `-VarDecl 0x1a5b611cf40 <col:9, col:17> col:13 b 'int' cinit
    |     `-IntegerLiteral 0x1a5b611cfa8 <col:17> 'int' 20
    `-CompoundStmt 0x1a5b611d0c0 <line:31:5, line:33:5>
        `-DeclStmt 0x1a5b611d0a8 <line:32:9, col:19>
        `-VarDecl 0x1a5b611d018 <col:9, col:17> col:13 c 'int' cinit
            `-IntegerLiteral 0x1a5b611d080 <col:17> 'int' 20
FunctionTemplateDecl 0x1a5b611d408 <F:\WorkSpace\AutoTestProject\AUTestTools\Src\test.cpp:35:1, line:36:15> col:6 bar
|-TemplateTypeParmDecl 0x1a5b611d140 <line:35:11, col:20> col:20 referenced typename depth 0 index 0 T
`-FunctionDecl 0x1a5b611d368 <line:36:1, col:15> col:6 bar 'void (T &&)'
`-ParmVarDecl 0x1a5b611d278 <col:10, col:14> col:14 t 'T &&'
** EndSourceFileAction for: F:\WorkSpace\AutoTestProject\AUTestTools\Src\test.cpp
enum class Cpp11Enum
{
    RED = 10,
    BLUE = 20
};

struct Wowza
{
    virtual ~Wowza() = default;
    virtual void foo(int i = 0) = 0;
};

struct Badabang : Wowza
{
    void foo(int) override;

    bool operator==(const Badabang &o) const;
};

// Begin function testif_else returning void
void testif_else()
{
    if (1)
    // the 'if' part
    {
        int a = 10;
    }
    else // the 'else' part
    if (2)
    // the 'if' part
    {
        int b = 20;
    }
    else
    // the 'else' part
    {
        int c = 20;
    }
}
// End function testif_else

使用 clang-cl 为前端

使用 clang-cl 主要需要注意一点，就是需要在环境变量中配置 include 与 lib，指向你的 msvc-cl 的 include 与 lib路径，LLVM 和 clang 的 include 与 lib 路径。在 windows 下的话还需要添加 windows sdk 相关的 include 与 lib 路径。以防头文件找不到编译失败。如下图：

以源码的方式集成到项目中

可能你遇到了和我一样的困扰，就是想要调试一个关于源码 AST 树相关的功能，需要先在 llvm-project 项目中将你的功能模块编译成库，然后在链接到你的项目中去，不说 llvm-project 体积巨大，打开项目浪费时间，单单这操作也是够繁琐了。因此，这里我整理了下如何使用源码在你的项目中去编译。

首先，确保你项目中可以通过 find_package 查找到 Clang 与 LLVM，以及可以使用库的方式链接通过。

然后，需要编写基于 libTooling 工具的源码，这里我将之前使用过的 loopConvert.cpp 拷贝过来直接用。接下来就是修改 CMakeLists.txt 了。参考如下：

sh 复制代码

find_package(LLVM REQUIRED CONFIG)
find_package(Clang REQUIRED CONFIG)

set(AUTESTSRC
main.cpp
LoopConvert.cpp
)

set(CLANG_LINK_LIBRARIES
libclang
clangTooling
clangARCMigrate
clangAST
clangASTMatchers
clangAnalysis
clangBasic
clangCodeGen
clangDriver
clangEdit
clangFrontend
clangFrontendTool
clangLex
clangParse
clangRewrite
clangRewriteFrontend
clangSema
clangSerialization
clangCodeGen
)

function(clang_target_link target type)
if (CLANG_LINK_CLANG_DYLIB)
    target_link_libraries(${target} ${type} clang_shared)
else()
    target_link_libraries(${target} ${type} ${ARGN})
endif()
endfunction()

add_executable(${PROJECT_NAME} ${HEAD_FILES} ${AUTESTSRC})

clang_target_link(${PROJECT_NAME} PRIVATE ${CLANG_LINK_LIBRARIES})

End

这样我们就成功的生成了定制工具、定制的 libTooling 工具以及通过源码的方式集成到自己的项目中了。