[BUG] LLDB shipped with NDK isn't able to find python 3.9 library

[rprichard]

I haven't tested ndk-gdb, but I suspect it's broken. The python 3.9 dynamic library isn't in the toolchain's lib64 directory, but is instead in its python3/lib64 directory. On Linux and Darwin, there isn't an rpath pointing at the python3 directory.

macOS:

$ /Users/rprichard/android-ndk-r23/toolchains/llvm/prebuilt/darwin-x86_64/bin/lldb 
dyld: Library not loaded: @rpath/libpython3.9.dylib
  Referenced from: /Users/rprichard/android-ndk-r23/toolchains/llvm/prebuilt/darwin-x86_64/lib64/liblldb.12.0.5git.dylib
  Reason: image not found

Linux:

rprichard@cashew:/x/android-ndk-r23$ docker run -it -v$PWD:$PWD ubuntu:20.04 $PWD/toolchains/llvm/prebuilt/linux-x86_64/bin/lldb
/x/android-ndk-r23/toolchains/llvm/prebuilt/linux-x86_64/bin/lldb: error while loading shared libraries: libpython3.9.so.1.0: cannot open shared object file: No such file or directory

Windows:

C:\src>set PATH=C:\Windows\System32;C:\Windows
C:\src>c:\src\android-ndk-r23\toolchains\llvm\prebuilt\windows-x86_64\bin\lldb.exe

A dialog appears: The code execution cannot proceed because python39.dll was not found.

[MlsDmitry]

I overcame this issue via appending python library to search path.

export DYLD_LIBRARY_PATH="/Users//Library/Android/sdk/ndk//toolchains/llvm/prebuilt/darwin-x86_64/python3/lib"

Then it failed with another message:
"terminals database is inaccessible"

[DanAlbert]

The lldb.sh script in the same directory solves this issue. Does this bug predate that, or is the question here "why is this necessary?"

@pirama-arumuga-nainar, is the script something we need, or just a workaround while we wait for someone to fix the RPATH?

[pirama-arumuga-nainar]

We also use the script to set PYTHONHOME - which IIUC can't be eliminated.

I also don't see a build option to set just lldb's linker flags without adding this RPATH to the rest of the tools. So let's continue using the script to set LD_LIBRARY_PATH as well.

[appujee]

Fixed in: https://android-review.git.corp.google.com/c/toolchain/llvm_android/+/2587443