[llvm-dev] DYLD implicit interposition

Michael Clark via llvm-dev llvm-dev at lists.llvm.org
Sat Jun 17 21:12:46 PDT 2017


From reading the ASAN diffs it seems implicit interposing is the ability to use dyld interposition without requiring DYLD_INSERT_LIBRARIES i.e. implicit interposing works by linking to the dylib that contains the interposers. Previously ASAN runtime would re-exec the program with DYLD_INSERT_LIBRARIES and this is no longer required with implicit interposing.

On 18/06/2017, at 7:00 AM, via llvm-dev <llvm-dev at lists.llvm.org> wrote:

>> You could use implicit interposing. This is a feature add so that ASAN binaries can avoid the the whole re-exec with DYLD_INSERT_LIBRARIES issue. It is not guaranteed to be stable, but in practice it is probably the most stable option short of using a hypervisor. The way it works:
> 
> Was is really added for ASAN ? I remember using dyld_interpose for a long time. It was already described in the Amit Singh edition of Mac OS X Internal book (which is older than clang). Or we are not talking about the same interpose ?


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