To build perl with AddressSanitizer, your Configure invocation should
look like:
- sh Configure -des -Dcc=clang -Accflags=-faddress-sanitizer \
- -Aldflags=-faddress-sanitizer -Alddlflags=-faddress-sanitizer
+ sh Configure -des -Dcc=clang \
+ -Accflags=-faddress-sanitizer -Aldflags=-faddress-sanitizer \
+ -Alddlflags=-shared\ -faddress-sanitizer
where these arguments mean:
Link the perl executable with AddressSanitizer.
-=item * -Alddlflags=-faddress-sanitizer
+=item * -Alddlflags=-shared\ -faddress-sanitizer
-Link dynamic extensions with AddressSanitizer.
-
-If you also pass C<-Duseshrplib> to Configure in order to build a
-shared perl library, then you must replace this by
-C<-Alddlflags=-shared\ -faddress-sanitizer>.
+Link dynamic extensions with AddressSanitizer. You must manually
+specify C<-shared> because using C<-Alddlflags=-shared> will prevent
+Configure from setting a default value for C<lddlflags>, which usually
+contains C<-shared> (at least on linux).
=back
Under ithreads the optree is read only. If you want to enforce this, to
check for write accesses from buggy code, compile with
-C<-DPL_OP_SLAB_ALLOC> to enable the OP slab allocator and
C<-DPERL_DEBUG_READONLY_OPS> to enable code that allocates op memory
-via C<mmap>, and sets it read-only at run time. Any write access to an
-op results in a C<SIGBUS> and abort.
+via C<mmap>, and sets it read-only when it is attached to a subroutine. Any
+write access to an op results in a C<SIGBUS> and abort.
This code is intended for development only, and may not be portable
even to all Unix variants. Also, it is an 80% solution, in that it
-isn't able to make all ops read only. Specifically it
-
-=over
-
-=item * 1
-
-Only sets read-only on all slabs of ops at C<CHECK> time, hence ops
-allocated later via C<require> or C<eval> will be re-write
-
-=item * 2
-
-Turns an entire slab of ops read-write if the refcount of any op in the
-slab needs to be decreased.
-
-=item * 3
-
-Turns an entire slab of ops read-write if any op from the slab is
-freed.
-
-=back
-
-It's not possible to turn the slabs to read-only after an action
-requiring read-write access, as either can happen during op tree
-building time, so there may still be legitimate write access.
+isn't able to make all ops read only. Specifically it does not apply to op
+slabs belonging to C<BEGIN> blocks.
-However, as an 80% solution it is still effective, as currently it
-catches a write access during the generation of F<Config.pm>, which
-means that we can't yet build F<perl> with this enabled.
+However, as an 80% solution it is still effective, as it has caught bugs in
+the past.
=head2 The .i Targets