llvm dev - Jun 2017 - DYLD implicit interposition

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
?

Thanks for the pointer. I missed the part about ‘implicit’. This is a great
addition.
> Le 18 juin 2017 à 06:12, Michael Clark via llvm-dev <llvm-dev at
lists.llvm.org> a écrit :
> 
> 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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