[llvm-dev] Ld64.lld cannot find Foundation framework

[Edmund Furse via llvm-dev]

Dear LLVM community I need some help please.

I want to use LLVM's clang and lld within a MacOSX sandboxed app.  This is because sandboxing does not allow calls to /usr/bin/clang.

The clang binary works fine to compile a file, but ld64.lld comes up with the error "cannot find framework".

However similar arguments using /usr/bin/ld instead of ld64.lld works fine.

Here are the details:

Here is the call using /usr/bin/ld:

/usr/bin/ld HelloObjC.o -o HelloObjC  -v -sdk_version 10.14.0 -macosx_version_min 10.14.0 -demangle -lto_library /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/libLTO.dylib -dynamic -arch x86_64 -framework Foundation -framework Cocoa -syslibroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk  -lSystem /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/10.0.1/lib/darwin/libclang_rt.osx.a -F/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk

This works correctly.

Here is the call using ld64.lld:

/Users/edmundfurse/Documents/NewClang/NewClangM21b/NewClangM21/Tools/bin/ld64.lld HelloObjC.o -o HelloObjC  -v -sdk_version 10.14.0 -macosx_version_min 10.14.0 -demangle -lto_library /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/libLTO.dylib -dynamic -arch x86_64 -framework Foundation -framework Cocoa -syslibroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk -L/usr/local/lib -lSystem /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/10.0.1/lib/darwin/libclang_rt.osx.a -F/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk

gives the error message:

Library search paths:

    /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/usr/lib

Framework search paths:

    /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk

    /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/System/Library/Frameworks

ld64.lld: error: Unable to find framework for -framework Foundation

Any suggestions welcome.

[James Y Knight via llvm-dev]

The MachO port of lld (ld64.lld) doesn't work. There is recently some activity to start to fix this situation, but for now you need to use Apple's linker.

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[Edmund Furse via llvm-dev]

Thanks for your reply.  Two questions:

1). Will ld64.lld be fixed in LLVM v11.0 and when is this likely to be?

2). You mention Apple’s linker, by which I assume you mean GNU’s ld.

Is it possible to get a binary version of ld (preferably that does not use other things from /usr/bin)?

Thanks

[James Y Knight via llvm-dev]

On Thu, May 7, 2020 at 1:54 PM Edmund Furse <edmund...@imitation.uk.com> wrote:

Thanks for your reply.  Two questions:

1). Will ld64.lld be fixed in LLVM v11.0 and when is this likely to be?

Likely won't be fixed that soon.

2). You mention Apple’s linker, by which I assume you mean GNU’s ld.

Is it possible to get a binary version of ld (preferably that does not use other things from /usr/bin)?

No, Apple does not use GNU ld, they have their own linker, "ld64". That's what you ran as /usr/bin/ld on your mac.

[Edmund Furse via llvm-dev]

James, many thanks.

Is there any linker available for Macs that has a freely available binary version?

I thought maybe that GNU’s linker might fit the bill?

I cannot use Apple’s linker from /usr/bin/ as it is not allowed to make external calls from a sandboxed app.

Hence my interest in the LLVM lld.

[Shoaib Meenai via llvm-dev]

You can always download source tarballs of ld64 from https://opensource.apple.com/tarballs/ld64/ and build it yourself. (https://github.com/michaeleisel/zld might also be interesting to you, depending on what all you plan to use the linker for.)

[Edmund Furse via llvm-dev]

Thank you for your ideas.I have tried both of your suggestions.

1).  Apple’s ld64 downloads ok and the xcodeproj launches ok.  However a build gives six errors including:

Unable to find sdk ‘Macosx.internal’

tapi/tapi.h file not found

macho-/dyld+priv_h file not found

llvm-c/lto.h file not found

Why cannot Apple provide code that works?  Has anyone managed to overcome these problems?

2). lzd stores some metadata in /tmp/zld-… and hence will not be allowed in a Sandboxed app.

[mayuyu.io via llvm-dev]

That’s because it requires Apple Internal SDK.

Zhang

在 2020年5月8日，15:58，Edmund Furse via llvm-dev <llvm...@lists.llvm.org> 写道：

Thank you for your ideas.I have tried both of your suggestions.