leimao / ABI-Breaking-Change-Demo

ABI Breaking Change Demo

ABI Breaking Change Demo

Introduction

An ABI breaking change in library can lead to the dependent application or library undefined behavior if they are not correctly recompiled and linked to the updated library.

ABI Breaking Change Demo

# Build library V1.
cd library_v1
g++ -g -fdump-lang-class -shared -fPIC library.cpp -I. -o liblibrary.so
cd ..

# Build library V2.
cd library_v2
g++ -g -fdump-lang-class -shared -fPIC library.cpp -I. -o liblibrary.so
cd ..

# Build application.
cd application
# Build application using the header from library V1.
g++ -g -fdump-lang-class -o app_header_v1.o -c app.cpp -I../library_v1
# Build application using the header from library V2.
g++ -g -fdump-lang-class -o app_header_v2.o -c app.cpp -I../library_v2

# Link application to libraries.
# There are no linker errors, suggesting that Rectangle::area() that is
# used in the app.cpp have been successfully found.
# Link application using the header from library V1 correctly with library V1.
g++ -o app_header_v1_library_v1.app app_header_v1.o -L../library_v1 -llibrary
# Link application using the header from library V2 correctly with library V2.
g++ -o app_header_v2_library_v2.app app_header_v2.o -L../library_v2 -llibrary
# Link application using the header from library V1 correctly with library V2.
# ABI breaking change (vtable conflict)
g++ -o app_header_v1_library_v2.app app_header_v1.o -L../library_v2 -llibrary
# Link application using the header from library V2 correctly with library V1.
# ABI breaking change (vtable conflict)
g++ -o app_header_v2_library_v1.app app_header_v2.o -L../library_v1 -llibrary

# This works as expected.
LD_LIBRARY_PATH=../library_v1 ./app_header_v1_library_v1.app
# This does not work.
# Segmentation fault (core dumped)
LD_LIBRARY_PATH=../library_v1 ./app_header_v2_library_v1.app
# This works as expected.
LD_LIBRARY_PATH=../library_v2 ./app_header_v2_library_v2.app
# This does not work.
# Area: 16
# terminate called after throwing an instance of 'std::runtime_error'
#   what():  Area is not correct.
# Aborted (core dumped)
LD_LIBRARY_PATH=../library_v2 ./app_header_v1_library_v2.app

cd ..