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| author | Ryan Prichard <rprichard@google.com> | 2018-03-27 22:10:55 -0700 |
|---|---|---|
| committer | Ryan Prichard <rprichard@google.com> | 2018-03-30 13:56:03 -0700 |
| commit | 470b66644b912ac3025ea30141f2f327bb879445 (patch) | |
| tree | 919718ba86bbabe7bec99cd2087f479b5594488f /libdl | |
| parent | ef59154d4129b132884f74ea0f38146f67383d81 (diff) | |
| download | android_bionic-470b66644b912ac3025ea30141f2f327bb879445.tar.gz android_bionic-470b66644b912ac3025ea30141f2f327bb879445.tar.bz2 android_bionic-470b66644b912ac3025ea30141f2f327bb879445.zip | |
Break libdl.so and ld-android.so's dependency on libc.so.
* Specify "nocrt: true" to avoid calling __cxa_finalize.
* Define a dummy __aeabi_unwind_cpp_pr0 for arm32.
Bug: b/62815515
Bug: b/73873002
Test: boot AOSP hikey960-userdebug
Test: run ndk_cxa_example in special /system/bin/debug namespace
Test: run Bionic unit tests
Change-Id: I59bcb100a2753286b59c51a47d7a183507219a07
Diffstat (limited to 'libdl')
| -rw-r--r-- | libdl/Android.bp | 7 | ||||
| -rw-r--r-- | libdl/libdl.cpp | 12 |
2 files changed, 13 insertions, 6 deletions
diff --git a/libdl/Android.bp b/libdl/Android.bp index 082cdead1..5998f9bbc 100644 --- a/libdl/Android.bp +++ b/libdl/Android.bp @@ -84,12 +84,7 @@ cc_library { ], stl: "none", - // NOTE: libdl needs __aeabi_unwind_cpp_pr0 from libgcc.a but libgcc.a needs a - // few symbols from libc. Using --no-undefined here results in having to link - // against libc creating a circular dependency which is removed and we end up - // with missing symbols. Since this library is just a bunch of stubs, we set - // LOCAL_ALLOW_UNDEFINED_SYMBOLS to remove --no-undefined from the linker flags. - allow_undefined_symbols: true, + nocrt: true, system_shared_libs: [], // This is placeholder library the actual implementation is (currently) diff --git a/libdl/libdl.cpp b/libdl/libdl.cpp index c8340888e..402804ec5 100644 --- a/libdl/libdl.cpp +++ b/libdl/libdl.cpp @@ -214,4 +214,16 @@ struct android_namespace_t* android_get_exported_namespace(const char* name) { return __loader_android_get_exported_namespace(name); } +#if defined(__arm__) +// An arm32 unwinding table has an R_ARM_NONE relocation to +// __aeabi_unwind_cpp_pr0. This shared library will never invoke the unwinder, +// so it doesn't actually need the routine. Define a dummy version here, +// because the real version calls libc functions (e.g. memcpy, abort), which +// would create a dependency cycle with libc.so. +__attribute__((visibility("hidden"))) +void __aeabi_unwind_cpp_pr0() { + __builtin_trap(); +} +#endif + } // extern "C" |