What is the right way of using a custom (built by me from llvm sources) asan library?
During compilation I am using -fsanitize=address.
But what should I use for linking? It is recommended everywhere to use -static-libasan or -shared-libasan, but as far as I understand, linker will use the library that comes with compiler (not mine).
Shall I drop -static-libasan / -shared-libasan and just link against the clang_rt.asan-dynamic-x86_64 built by me? Or something else?
if you use -shared-asan at build time it will link to the shared lib which is what you want, and it will default to that standard path, but you should be able to easily override it when you go to run your app to use your own build using LD_PRELOAD.
for example:
LD_PRELOAD=/home/yourname/llvm/lib/clang_rt.asan...so myapp
so...the linker won't load the standard one because yours will be loaded into memory already and myapp will link up to it.
you still might need to make sure the version you are building from source is the same or close enough to the one that it linked to myapp at build time.
Related
I have an application Unity that uses the iOS static library. Then this application Unity is build in XCode. I found several utilities that allow you to obfuscate the library in the application. for example this - PPiOS-Rename.
I carefully read their documentation "Obfuscate Static Libraries", but at the time of building, the iOS static library are already "hidden in the root" of the Unity app, and XCode cannot obfuscate this.
So I need to first obfuscate the library and then add it to the application. or is it not possible?
In my understanding of the documentation PPiOS-Rename stays an external tool, just the files *.plist can be added into the releases, for being able to use the tool on the compiled releases.
I might be completely wrong about it, especially as without iOS I can't test it, but I'd check if my statement is right and if you can omit the step to include the library in your compiled releases.
About handling of *.plist files, follow the instructions on the linked page, I'm not sure if you have one or more in the end. As it doesn't seem relevant to the core of your question, I never verified it deeper.
I'm very interested in using GStreamer's iOS framework http://docs.gstreamer.com/display/GstSDK/Installing+for+iOS+development for video streaming, but when I add the framework to a blank project and add a few lines of code to take advantage of its powerful features, the final IPA is 27MB. This is just way to big to be adding to my project, what is the best way to go about stripping this down the the bare necessities as I'm sure I'm only using a small percent of the code that is included in the SDK.
Here's a pic showing the package contents of the IPA:
Thanks!
In the gst_ios_main.h you can disable all the plugins that you don't need (make sure to enable linker optimizations so that unused code is removed). If that's not enough, you can build your own stripped down version of the iOS binaries with http://cgit.freedesktop.org/gstreamer/cerbero/ (you need to remove things from the .package and .recipe files to only build what you need). Just disabling things from gst_ios_main.h should be enough in 99% of the cases though.
Note that by default you'll build applications for multiple architectures, as such the resulting application will be rather large. Depending on your use case you can drop some architectures.
On another note, gstreamer.com is providing an completely outdated version of GStreamer and is in no way related to the GStreamer project. The official website is http://gstreamer.freedesktop.org .
SDKs have their source code encapsulated away from you, the user. You get access only to header files. Thus you just can't extract some class from it because you don't have access to the implementation file.
Of course if this library is opensource you can attempt to isolate one class, but sometimes everything is so deeply connected, that it is close to impossible.
I am trying to add the GPUImage framework/library according to this:
github.com/BradLarson/GPUImage
and I am stuck at the point of setting the Header Search Path. I tried setting a path but when I tried importing#import "GPUImage.h" I got an error saying it is not found. Maybe I put in the wrong path? I'm confused about what I should do because I have never used this before (very new to programming). Any help would be greatly appreciated.
First, if you're developing using Xcode 6, you might look at using the new framework support present in iOS 8 (and back to iOS 7, near as I can tell). The project has a true iOS framework that eliminates the need for setting paths to headers, like static libraries require. See the "Adding this as a framework (module) to your Mac or iOS project" section of the instructions for how to use this.
If you're targeting an older version of iOS and/or using an older version of Xcode, you'll need to set the Header Search Paths value in your build settings to be the path to where you installed GPUImage from where your application resides. For example, the sample applications in the examples/iOS directory use a path of
../../../framework
The .. elements in that tell it to step one directory back from the location of your application project. Since the examples reside in GPUImage/examples/iOS/[project], the above relative path leads to GPUImage/framework. If you placed your project and GPUImage in the same encompassing directory, you might use
../GPUImage/framework
instead.
In that path setting, make sure you set the option on the right to "recursive" as well.
Use the sample applications as templates, and compare how they are set up to your application to find areas where you might have deviated from the listed setup instructions. About the hardest part of those instructions is getting the relative path right.
I suggest you use cocoapods. It handles gracefully library dependencies and GPUImage is present there.
cocoapods.org
It is also fairly easy to install and use
I am trying to get some a medium-to-large sized code base that is, frankly, well written with a high degree of portability.
I decided to package it as a loadable bundle (plugin) and piggy-backed off of one of the template app projects and followed some tutorials about adding a target for loadable bundles within an app.
Also, this loadable bundle depends on a custom framework which I built for iOS and added it as a dependent for the loadable bundle. ie. The plugin links to a framework wrapper for a static lib.
The custom framework built successfully. Granted I have not yet verified that it works. The idea is to test the integrated functionality.
My build settings are largely defaults with the exception of some preprocessor defines.
Because I don't really understand the code base yet, I am literally adding one file-at-a-time to the plugin target and building cleanly every 3-4 files added.
The build completes successfully but with many, many warnings as follows, with paths to intermediate build results...etc.:
"file was built for unsupported file format with a series of hex characters () which is not the architecture being linked (armv7s)". When I converted the hex chars to ascii it just showed "#1 /Users/my-username/? ".
When I do a 'file' on any .o in the intermediate build results, I get "ASCII c program text, with very long lines"
What am I doing wrong? What does that mean?
Thank you so much for your time.
The short answer is this:
If you get this message, then your project settings are messed up.
If you are linking your app against custom frameworks, make sure they are built as fat binaries
You will need to know very clearly the meanings of active architecture and how it is used and whether or not you want to only build the active architecture for your app, or all of the possible architectures.
If you are, like me, inheriting a slew of portable code that depended heavily on gcc and its extensions, expect to make changes around builtin* attributes and to make heavy use of __clang to make available macros that used to be defined through the GNUC et al.
Also, you will need to use the -E for clang to debug/understand the preprocessing and the file inclusion. That said, don't forget to take it out because effectively what will happen is that your .o will just contain text and the build may succeed, but the linker will give you the odd message subject of this question.
Finally, do understand that Xcode, like any piece of complex software, is buggy. Sometimes, it will keep settings that you get rid off. In my case, I included custom frameworks which I built after placing them in a local dir. Then I deleted them from the project and opted to trash when prompted. The build kept failing because the linker for some reason was looking for the local directory. You would have to edit the *.pbxproj and manually remove them.
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.