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Replace IFN_TRAP with BUILT_IN_UNREACHABLE_TRAP [PR107300]

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For PR106099 I've added IFN_TRAP as an alternative to __builtin_trap
meant for __builtin_unreachable purposes (e.g. with -funreachable-traps
or some sanitizers) which doesn't need vops because __builtin_unreachable
doesn't need them either.  This works in various cases, but unfortunately
IPA likes to decide on the redirection to unreachable just by tweaking
the cgraph edge to point to a different FUNCTION_DECL.  As internal
functions don't have a decl, this causes problems like in the following
testcase.

The following patch fixes it by removing IFN_TRAP again and replacing
it with user inaccessible BUILT_IN_UNREACHABLE_TRAP, so that e.g.
builtin_decl_unreachable can return it directly and we don't need to tweak
it later in wherever we actually replace the call stmt.

2023-02-02  Jakub Jelinek  <jakub@redhat.com>

	PR ipa/107300
	* builtins.def (BUILT_IN_UNREACHABLE_TRAP): New builtin.
	* internal-fn.def (TRAP): Remove.
	* internal-fn.cc (expand_TRAP): Remove.
	* tree.cc (build_common_builtin_nodes): Define
	BUILT_IN_UNREACHABLE_TRAP if not yet defined.
	(builtin_decl_unreachable): Use BUILT_IN_UNREACHABLE_TRAP
	instead of BUILT_IN_TRAP.
	* gimple.cc (gimple_build_builtin_unreachable): Remove
	emitting internal function for BUILT_IN_TRAP.
	* asan.cc (maybe_instrument_call): Handle BUILT_IN_UNREACHABLE_TRAP.
	* cgraph.cc (cgraph_edge::verify_corresponds_to_fndecl): Handle
	BUILT_IN_UNREACHABLE_TRAP instead of BUILT_IN_TRAP.
	* ipa-devirt.cc (possible_polymorphic_call_target_p): Handle
	BUILT_IN_UNREACHABLE_TRAP.
	* builtins.cc (expand_builtin, is_inexpensive_builtin): Likewise.
	* tree-cfg.cc (verify_gimple_call,
	pass_warn_function_return::execute): Likewise.
	* attribs.cc (decl_attributes): Don't report exclusions on
	BUILT_IN_UNREACHABLE_TRAP either.

	* gcc.dg/pr107300.c: New test.
This commit is contained in:
Jakub Jelinek 2023-02-02 10:54:54 +01:00
parent 209f02b0a9
commit d2423144eb
12 changed files with 42 additions and 26 deletions
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1
gcc/asan.cc
View file

@ -2951,6 +2951,7 @@ maybe_instrument_call (gimple_stmt_iterator *iter)
switch (DECL_FUNCTION_CODE (callee))
{
case BUILT_IN_UNREACHABLE:
case BUILT_IN_UNREACHABLE_TRAP:
case BUILT_IN_TRAP:
/* Don't instrument these. */
return false;

1
gcc/attribs.cc
View file

@ -846,6 +846,7 @@ decl_attributes (tree *node, tree attributes, int flags,
|| !DECL_P (*anode)
|| DECL_BUILT_IN_CLASS (*anode) != BUILT_IN_NORMAL
|| (DECL_FUNCTION_CODE (*anode) != BUILT_IN_UNREACHABLE
&& DECL_FUNCTION_CODE (*anode) != BUILT_IN_UNREACHABLE_TRAP
&& (DECL_FUNCTION_CODE (*anode)
!= BUILT_IN_UBSAN_HANDLE_BUILTIN_UNREACHABLE)))
{

2
gcc/builtins.cc
View file

@ -7844,6 +7844,7 @@ expand_builtin (tree exp, rtx target, rtx subtarget, machine_mode mode,
break;
case BUILT_IN_TRAP:
case BUILT_IN_UNREACHABLE_TRAP:
expand_builtin_trap ();
return const0_rtx;
@ -11310,6 +11311,7 @@ is_inexpensive_builtin (tree decl)
case BUILT_IN_VA_ARG_PACK_LEN:
case BUILT_IN_VA_COPY:
case BUILT_IN_TRAP:
case BUILT_IN_UNREACHABLE_TRAP:
case BUILT_IN_SAVEREGS:
case BUILT_IN_POPCOUNTL:
case BUILT_IN_POPCOUNTLL:

1
gcc/builtins.def
View file

@ -1048,6 +1048,7 @@ DEF_GCC_BUILTIN (BUILT_IN_SETJMP, "setjmp", BT_FN_INT_PTR, ATTR_RT_NOTHRO
DEF_EXT_LIB_BUILTIN (BUILT_IN_STRFMON, "strfmon", BT_FN_SSIZE_STRING_SIZE_CONST_STRING_VAR, ATTR_FORMAT_STRFMON_NOTHROW_3_4)
DEF_LIB_BUILTIN (BUILT_IN_STRFTIME, "strftime", BT_FN_SIZE_STRING_SIZE_CONST_STRING_CONST_TM_PTR, ATTR_FORMAT_STRFTIME_NOTHROW_3_0)
DEF_GCC_BUILTIN (BUILT_IN_TRAP, "trap", BT_FN_VOID, ATTR_NORETURN_NOTHROW_LEAF_COLD_LIST)
DEF_GCC_BUILTIN (BUILT_IN_UNREACHABLE_TRAP, "unreachable trap", BT_FN_VOID, ATTR_CONST_NORETURN_NOTHROW_LEAF_COLD_LIST)
DEF_GCC_BUILTIN (BUILT_IN_UNREACHABLE, "unreachable", BT_FN_VOID, ATTR_CONST_NORETURN_NOTHROW_LEAF_COLD_LIST)
DEF_GCC_BUILTIN (BUILT_IN_UNWIND_INIT, "unwind_init", BT_FN_VOID, ATTR_NULL)
DEF_GCC_BUILTIN (BUILT_IN_UPDATE_SETJMP_BUF, "update_setjmp_buf", BT_FN_VOID_PTR, ATTR_NULL)

4
gcc/cgraph.cc
View file

@ -3248,11 +3248,11 @@ cgraph_edge::verify_corresponds_to_fndecl (tree decl)
node = node->ultimate_alias_target ();
/* Optimizers can redirect unreachable calls or calls triggering undefined
behavior to __builtin_unreachable or __builtin_trap. */
behavior to __builtin_unreachable or __builtin_unreachable trap. */
if (fndecl_built_in_p (callee->decl, BUILT_IN_NORMAL)
&& (DECL_FUNCTION_CODE (callee->decl) == BUILT_IN_UNREACHABLE
|| DECL_FUNCTION_CODE (callee->decl) == BUILT_IN_TRAP))
|| DECL_FUNCTION_CODE (callee->decl) == BUILT_IN_UNREACHABLE_TRAP))
return false;
if (callee->former_clone_of != node->decl

11
gcc/gimple.cc
View file

@ -430,16 +430,7 @@ gimple_build_builtin_unreachable (location_t loc)
{
tree data = NULL_TREE;
tree fn = sanitize_unreachable_fn (&data, loc);
gcall *g;
if (DECL_FUNCTION_CODE (fn) != BUILT_IN_TRAP)
g = gimple_build_call (fn, data != NULL_TREE, data);
else
{
/* Instead of __builtin_trap use .TRAP, so that it doesn't
need vops. */
gcc_checking_assert (data == NULL_TREE);
g = gimple_build_call_internal (IFN_TRAP, 0);
}
gcall *g = gimple_build_call (fn, data != NULL_TREE, data);
gimple_call_set_ctrl_altering (g, true);
gimple_set_location (g, loc);
return g;

6
gcc/internal-fn.cc
View file

@ -4517,12 +4517,6 @@ expand_SPACESHIP (internal_fn, gcall *stmt)
emit_move_insn (target, ops[0].value);
}
void
expand_TRAP (internal_fn, gcall *)
{
expand_builtin_trap ();
}
void
expand_ASSUME (internal_fn, gcall *)
{

5
gcc/internal-fn.def
View file

@ -457,11 +457,6 @@ DEF_INTERNAL_FN (SHUFFLEVECTOR, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
/* <=> optimization. */
DEF_INTERNAL_FN (SPACESHIP, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
/* __builtin_trap created from/for __builtin_unreachable. */
DEF_INTERNAL_FN (TRAP, ECF_CONST | ECF_LEAF | ECF_NORETURN
| ECF_NOTHROW | ECF_COLD | ECF_LOOPING_CONST_OR_PURE,
NULL)
/* [[assume (cond)]]. */
DEF_INTERNAL_FN (ASSUME, ECF_CONST | ECF_LEAF | ECF_NOTHROW
| ECF_LOOPING_CONST_OR_PURE, NULL)

6
gcc/ipa-devirt.cc
View file

@ -3471,8 +3471,10 @@ possible_polymorphic_call_target_p (tree otr_type,
unsigned int i;
bool final;
if (fndecl_built_in_p (n->decl, BUILT_IN_UNREACHABLE)
|| fndecl_built_in_p (n->decl, BUILT_IN_TRAP))
if (fndecl_built_in_p (n->decl, BUILT_IN_NORMAL)
&& (DECL_FUNCTION_CODE (n->decl) == BUILT_IN_UNREACHABLE
|| DECL_FUNCTION_CODE (n->decl) == BUILT_IN_TRAP
|| DECL_FUNCTION_CODE (n->decl) == BUILT_IN_UNREACHABLE_TRAP))
return true;
if (is_cxa_pure_virtual_p (n->decl))

19
gcc/testsuite/gcc.dg/pr107300.c Normal file
View file

@ -0,0 +1,19 @@
/* PR ipa/107300 */
/* { dg-do compile } */
/* { dg-options "-O2 -fipa-cp-clone -funreachable-traps -fno-inline" } */
void
bar (int x, int y)
{
if (x)
__builtin_unreachable ();
if (y)
__builtin_abort ();
}
void
foo (void)
{
bar (0, 0);
}

3
gcc/tree-cfg.cc
View file

@ -3503,6 +3503,7 @@ verify_gimple_call (gcall *stmt)
switch (DECL_FUNCTION_CODE (fndecl))
{
case BUILT_IN_UNREACHABLE:
case BUILT_IN_UNREACHABLE_TRAP:
case BUILT_IN_TRAP:
if (gimple_call_num_args (stmt) > 0)
{
@ -9681,6 +9682,8 @@ pass_warn_function_return::execute (function *fun)
&& ((LOCATION_LOCUS (gimple_location (last))
== BUILTINS_LOCATION
&& (gimple_call_builtin_p (last, BUILT_IN_UNREACHABLE)
|| gimple_call_builtin_p (last,
BUILT_IN_UNREACHABLE_TRAP)
|| gimple_call_builtin_p (last, BUILT_IN_TRAP)))
|| gimple_call_builtin_p (last, ubsan_missing_ret)))
{

9
gcc/tree.cc
View file

@ -9758,6 +9758,7 @@ build_common_builtin_nodes (void)
if (!builtin_decl_explicit_p (BUILT_IN_UNREACHABLE)
|| !builtin_decl_explicit_p (BUILT_IN_TRAP)
|| !builtin_decl_explicit_p (BUILT_IN_UNREACHABLE_TRAP)
|| !builtin_decl_explicit_p (BUILT_IN_ABORT))
{
ftype = build_function_type (void_type_node, void_list_node);
@ -9767,6 +9768,12 @@ build_common_builtin_nodes (void)
"__builtin_unreachable",
ECF_NOTHROW | ECF_LEAF | ECF_NORETURN
| ECF_CONST | ECF_COLD);
if (!builtin_decl_explicit_p (BUILT_IN_UNREACHABLE_TRAP))
local_define_builtin ("__builtin_unreachable trap", ftype,
BUILT_IN_UNREACHABLE_TRAP,
"__builtin_unreachable trap",
ECF_NOTHROW | ECF_LEAF | ECF_NORETURN
| ECF_CONST | ECF_COLD);
if (!builtin_decl_explicit_p (BUILT_IN_ABORT))
local_define_builtin ("__builtin_abort", ftype, BUILT_IN_ABORT,
"abort",
@ -10908,7 +10915,7 @@ builtin_decl_unreachable ()
if (sanitize_flags_p (SANITIZE_UNREACHABLE)
? (flag_sanitize_trap & SANITIZE_UNREACHABLE)
: flag_unreachable_traps)
fncode = BUILT_IN_TRAP;
fncode = BUILT_IN_UNREACHABLE_TRAP;
/* For non-trapping sanitize, we will rewrite __builtin_unreachable () later,
in the sanopt pass. */