Replace IFN_TRAP with BUILT_IN_UNREACHABLE_TRAP [PR107300]

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.

diff --git a/gcc/asan.cc b/gcc/asan.cc
index d833f89..57834b7 100644 (file)
--- a/gcc/asan.cc
+++ b/gcc/asan.cc
@@ -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;

diff --git a/gcc/attribs.cc b/gcc/attribs.cc
index 7db730c..b130001 100644 (file)
--- a/gcc/attribs.cc
+++ b/gcc/attribs.cc
@@ -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)))
            {

diff --git a/gcc/builtins.cc b/gcc/builtins.cc
index af45829..8327bcb 100644 (file)
--- a/gcc/builtins.cc
+++ b/gcc/builtins.cc
@@ -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:

diff --git a/gcc/builtins.def b/gcc/builtins.def
index 0afa4c5..4ad95a1 100644 (file)
--- a/gcc/builtins.def
+++ b/gcc/builtins.def
@@ -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)

diff --git a/gcc/cgraph.cc b/gcc/cgraph.cc
index 06bc980..f0d06bf 100644 (file)
--- a/gcc/cgraph.cc
+++ b/gcc/cgraph.cc
@@ -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

diff --git a/gcc/gimple.cc b/gcc/gimple.cc
index b97fbd5..5e4eda4 100644 (file)
--- a/gcc/gimple.cc
+++ b/gcc/gimple.cc
@@ -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;

diff --git a/gcc/internal-fn.cc b/gcc/internal-fn.cc
index 54ce04c..a7936ff 100644 (file)
--- a/gcc/internal-fn.cc
+++ b/gcc/internal-fn.cc
@@ -4518,12 +4518,6 @@ expand_SPACESHIP (internal_fn, gcall *stmt)
 }
 
 void
-expand_TRAP (internal_fn, gcall *)
-{
-  expand_builtin_trap ();
-}
-
-void
 expand_ASSUME (internal_fn, gcall *)
 {
 }

diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
index 1389c11..22b4a2d 100644 (file)
--- a/gcc/internal-fn.def
+++ b/gcc/internal-fn.def
@@ -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)

diff --git a/gcc/ipa-devirt.cc b/gcc/ipa-devirt.cc
index e26266e..14cf132 100644 (file)
--- a/gcc/ipa-devirt.cc
+++ b/gcc/ipa-devirt.cc
@@ -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))

diff --git a/gcc/testsuite/gcc.dg/pr107300.c b/gcc/testsuite/gcc.dg/pr107300.c
new file mode 100644 (file)
index 0000000..836908e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr107300.c
@@ -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);
+}

diff --git a/gcc/tree-cfg.cc b/gcc/tree-cfg.cc
index 9ecf138..a9fcc7f 100644 (file)
--- a/gcc/tree-cfg.cc
+++ b/gcc/tree-cfg.cc
@@ -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)))
                {

diff --git a/gcc/tree.cc b/gcc/tree.cc
index 80c0967..41ccbf3 100644 (file)
--- a/gcc/tree.cc
+++ b/gcc/tree.cc
@@ -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.  */