generate llvm bytecode for translation unit in clang plugin - clang

Good afternoon. In the clang documentation, I found a way to generate and paste code. So far, I have not used this method for the plugin, but if I understand correctly, it is possible (correct if not right - thanks).
I would like to know if it is possible to change the code at the bytecode level in the plugin, i.e. insert new stmt(clang::Stmt and its derivatives) into existing ones and give them to the compiler?
Pasting code at the source code level (clang::Rewriter) changes the project's source files, so it adds extra work.
Thank you

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clang -module-file-info doesn't generate any output

I'm trying to move a cross-compiled CMake project to Clang Modules to see whether compile time reduction is worth it. However, it seems that Clang is generating lots of duplicate modules in it's ModuleCache.
I'd like to figure out why (maybe some CMake config, etc), so I'm trying to run clang -module-file-info on the generated module files.
However, clang's output is just empty whenever I provide a proper module file. Am I doing anything wrong? Is there anything special that I need to take care of?
The files all have a reasonable size (from a few kB to a few MB), look fine in a Hex editor (start with CPCH, have some recognizable strings, etc) and whenever I specify a wrong file (or a file compiled with a different version of clang) I get the appropriate errors.
I've tried with clang 7.0.1 as well as 8.0.0.
I also tried --verbose but that didn't show any problems either.
To answer my own question:
clang doesn't output the stats on the command line, it puts it into a file by default written in the current directory.

Obtain compiler flags in skylark

I'd like to convert a CMake-based C++ library to bazel.
As part of the current CMake project, I'm using a libclang-based code generator that parses C++ headers and generates C++ code from the parsed AST. In order to do that, I need the actual compiler flags used to build the cc_library the header is part of. The flags are passed to the code generation tool so it can use clang's preprocessor.
Is there any way I could access the compiler flags used to build a dependency from a skylark- or gen_rule rule? I'm particularly interested in the include paths and defines.
We're working on it. Well, not right now, but will soon. You might want to subscribe to the corresponding issue, and maybe describe your requirements there so we take them into account when designing the API.

How to obfuscate iOS binary.

Hi, I'm just wondering how you could obfuscate functions in iOS binary?
If you tried to reverse iOS binaries using tools like ida you will see part of the binaries have obfuscated functions like all or partly named sub_xxxxxxxx but the other have human readable functions
Someone said, add those lines to the top of your header without any further explaining:
#define SecurityClass ah7p
#define checkCopyProtection xcyc
What the methods used to secure your App?
Sorry for the dumb question, but I'm new there and I ended up with no answer explained what I need.
There are a couple of ways to obfuscate an iOS binary.
Open Source compiler named llvm-obfuscate (https://github.com/obfuscator-llvm/obfuscator/wiki) It has some nice features to obfuscate during compilation. You are replacing your default compiler with that one.
There are for Windows of course VMWare oder Themdia that can post process but that is not the case.
Besides that I just know one more which is Liasoft antispy. It is a very advanced anti analysis toolkit that allows you to encrypt functions and much more during compilation using mixed Objective-C and C++ code. ( https://www.liasoft.de/en/products/antispy/ )
Not sure if one of these is the right one for you. Except these things you are pretty lost since Objective-C is a compiled language with lots of metadata.
Hope I could help you, this is my first post.
If you only care about obfuscating method names then the easiest way is to write relevant parts of your application in C or C++. For instance, you can rewrite your SecurityClass as a C++ class instead of Objective-C class. This will not make your code reverse-engineering-proof, but it will at least raise the bar a bit. (NOTE: I'm not saying this is the right thing to do from software engineering point of view, though).
If you need to obfuscate code, then you are in a search for a tool that can do this. There are several such tools, both commercial and free. One project for doing exactly this is obfuscator-llvm.

iOS SDKs: Renaming a lot of classes

I'm developing an iOS SDK that integrates other SDKs (Facebook SDK 3.5, for example).
To prevent collisions and allow my customers to import those SDKs as well, I want to rename all of the classes/enums in my code (for example, rename FBSession to RDFBSession, etc).
Is there an easy way to do this instead of going class-by-class and using Xcode's rename feature?
Apple provide a command-line tool called tops(1) that is designed for scripting large-scale code refactoring (renaming C functions, Objective-C methods, classes, and other tokens):
tops -verbose replace "FBSession" with "RDFBSession" Sources/*.[hm]
If you have a lot of replacements, you can put all of the replace... commands into a file that you pass with the -scriptfile option. The man page has more information on the more complex commands/options (and examples).
Xcode also offers textual Search and Replace. This will be faster than individual refactors, but it is ultimately less automated. You can make the step by step refactoring faster by first minimizing the project to the relevant dependencies/sources (if possible).
However, renaming the declarations in a library will not alter the symbol names of its associated binary. If it is distributed with a binary, then renaming will just result in linker errors or (in some cases) runtime errors.
The best idea if you need to use a 3rd party library which your clients might also use is to simply inform them they need to link the library with their app, then publish the version(s) the current release supports so they know they have some extra testing if they go too far ahead with some libraries.
I think that a better approach than simply renaming your classes would be to download Facebook's open source code, rename the classes there and compile a new static library with a set of renamed header files. Then you can be sure that no collisions occur and that you're using symbols that you named yourself.
I must warn you though - working like this may make updating the SDK a nightmare regardless of how you tackle this specific issue.

C++ Builder XE: find out where a specific h file is included

I'm currently porting a rather big project from C++ Builder 5 to the newest version, C++ Builder XE. It's my first experience with C++ Builder. I'm stuck with an error in a file, but I don't want to include this file anyway (it's code of a component not required anymore). I was not able to find out where and how this file is included, however. The compiler error does not give any hint at all apart from the error itself. How do you usually find out where a file is included?
The preprocessor is perfect for this. Right click on the cpp file which gives you the error in the project manager then choose "preprocess"
The output from this tells you every file and line number in the order they are processed. You can then search for the file in question, and the line above it is the file that included it.
This could conceivably be another header file as well, so it could be a long chain, but you can determine exactly where it comes from.
In the Project Options, enable the compiler's general messages. When the compiler encounters an error, you will be able to see the chain of includes that lead to the erroneous code.
If the files in question are rather sizable, a tool like Doxygen can be helpful in showing you the include dependencies (as well as call paths, etc.).
If it's just once or twice you'll have to do this, David Dean's suggestion of the preprocessor is golden.

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