https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83388
--- Comment #5 from rguenther at suse dot de <rguenther at suse dot de> --- On Tue, 12 Dec 2017, jakub at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83388 > > --- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> --- > (In reply to rguent...@suse.de from comment #3) > > > That said, what we are doing with the sanitizers is similar to what we are > > > doing with debug stmts, if compilation is with -flto -g and linking > > > without -g, > > > then > > > debug stmts are dropped. Likewise, IFN_*SAN* is dropped from the IL if > > > linking > > > without corresponding -fsanitize= options. > > > > Ah. So the error is about cgraph input not finding the corresponding > > GIMPLE call stmt that are referenced form a cgraph edge we input > > (e->call_stmt). This might be the case then when we drop those calls? > > We only drop internal fns, lto-streamer-in.c has: > if (is_gimple_call (stmt) > && gimple_call_internal_p (stmt)) > { > switch (gimple_call_internal_fn (stmt)) > { > case IFN_UBSAN_NULL: > if ((flag_sanitize > & (SANITIZE_NULL | SANITIZE_ALIGNMENT)) == 0) > remove = true; > etc. > Now, ifns shouldn't have any cgraph edges, should they? They shouldn't - but the error hints at stmts[uid] being NULL... Hmm. (gdb) p ref->referring $3 = (symtab_node *) 0x7ffff6e2f2e0 (gdb) p $3->debug () i.constprop.0/8 (i.constprop) @0x7ffff6e2f2e0 Type: function definition analyzed Visibility: References: c/0 (addr)f/1 (read) Referring: Read from file: /tmp/cc93A4UG.ltrans0.o Function i.constprop/8 is inline copy in j/3 Clone of i/2 Availability: local First run: 0 Function flags: count: 1073741825 (estimated locally) local Called by: j/3 (inlined) (1073741825 (estimated locally),1.00 per call) Calls: e/4 (1073741824 (estimated locally),1.00 per call) g/5 (354334802 (estimated locally),0.33 per call) $4 = void (gdb) p ref->referred->debug () c/0 (c) @0x7ffff6e30000 Type: variable definition analyzed Visibility: externally_visible prevailing_def_ironly_exp public common References: Referring: i.constprop.0/8 (addr) Read from file: /tmp/cc93A4UG.ltrans0.o Availability: available Varpool flags: $5 = void (gdb) p ref->lto_stmt_uid - 1 $6 = 2 (gdb) p stmts $7 = (gimple **) 0x2a5afb0 (gdb) p stmts[0] $8 = <gimple_call 0x7ffff6e30200> (gdb) p stmts[1] $9 = <gimple_cond 0x7ffff6e350f0> (gdb) p stmts[2] $10 = <gimple 0x0> (gdb) p stmts[3] $11 = <gimple_assign 0x7ffff6e35140> (gdb) p debug_gimple_stmt (stmt) # .MEM = VDEF <.MEM> UBSAN_NULL (&c, 3B, 0); $1 = void (gdb) p gimple_uid (stmt) $2 = 2 so we have a IPA ref reference to a variable in the IFN stmt which we remove. I suspect we're better off replacing non-debug stmts with GIMPLE_NOPs ...
