On Thu, Jun 16, 2022 at 09:32:02PM +0100, Jonathan Wakely wrote:
> It looks like clang has addressed this deficiency now:
> 
> https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html#usage

Thanks, that is roughly what I'd implement anyway and apparently they have
it already since 2015, we've added the -fsanitize-undefined-trap-on-error
support back in 2014 and didn't change it since then.

As a small divergence from clang, I chose -fsanitize-undefined-trap-on-error
to be a (deprecated) alias for -fsanitize-trap aka -fsanitize-trap=all
rather thn -fsanitize-trap=undefined which seems to be what clang does,
because for a deprecated option it is IMHO more important backwards
compatibility with what gcc did over the past 8 years rather than clang
compatibility.
Some sanitizers (e.g. asan, lsan, tsan) don't support traps,
-fsanitize-trap=address etc. will be rejected (if enabled at the end of
command line), -fno-sanitize-trap= can be specified even for them.
This is similar behavior to -fsanitize-recover=.
One complication is vptr sanitization, which can't easily trap,
as the whole slow path of the checking is inside of libubsan.
Previously, -fsanitize=vptr -fsanitize-undefined-trap-on-error
silently ignored vptr sanitization.
This patch similarly to what clang does will accept
-fsanitize-trap=all or -fsanitize-trap=undefined which enable
the vptr bit as trapping and again that causes silent disabling
of vptr sanitization, while -fsanitize-trap=vptr is rejected
(already during option processing).

So far quickly tested with make check-gcc check-g++ RUNTESTFLAGS=ubsan.exp,
ok for trunk if it passes full bootstrap/regtest?

2022-06-17  Jakub Jelinek  <ja...@redhat.com>

gcc/
        * common.opt (flag_sanitize_trap): New variable.
        (fsanitize-trap=, fsanitize-trap): New options.
        (fsanitize-undefined-trap-on-error): Change into deprecated alias
        for -fsanitize-trap=all.
        * opts.h (struct sanitizer_opts_s): Add can_trap member.
        * opts.cc (finish_options): Complain about unsupported
        -fsanitize-trap= options.
        (sanitizer_opts): Add can_trap values to all entries.
        (get_closest_sanitizer_option): Ignore -fsanitize-trap=
        options which have can_trap false.
        (parse_sanitizer_options): Add support for -fsanitize-trap=.
        For -fsanitize-trap=all, enable
        SANITIZE_UNDEFINED | SANITIZE_UNDEFINED_NONDEFAULT.  Disallow
        -fsanitize-trap=vptr here.
        (common_handle_option): Handle OPT_fsanitize_trap_ and
        OPT_fsanitize_trap.
        * sanopt.cc (maybe_optimize_ubsan_null_ifn): Check
        flag_sanitize_trap & SANITIZE_{NULL,ALIGNMENT} instead of
        flag_sanitize_undefined_trap_on_error.
        * gcc.cc (sanitize_spec_function): Use
        flag_sanitize & ~flag_sanitize_trap instead of flag_sanitize
        and drop use of flag_sanitize_undefined_trap_on_error in
        "undefined" handling.
        * ubsan.cc (ubsan_instrument_unreachable): Use
        flag_sanitize_trap & SANITIZE_??? instead of
        flag_sanitize_undefined_trap_on_error.
        (ubsan_expand_bounds_ifn, ubsan_expand_null_ifn,
        ubsan_expand_objsize_ifn, ubsan_expand_ptr_ifn,
        ubsan_build_overflow_builtin, instrument_bool_enum_load,
        ubsan_instrument_float_cast, instrument_nonnull_arg,
        instrument_nonnull_return, instrument_builtin): Likewise.
        * doc/invoke.texi (-fsanitize-trap=, -fsanitize-trap): Document.
        (-fsanitize-undefined-trap-on-error): Document as deprecated
        alias of -fsanitize-trap.
gcc/c-family/
        * c-ubsan.cc (ubsan_instrument_division, ubsan_instrument_shift):
        Use flag_sanitize_trap & SANITIZE_??? instead of
        flag_sanitize_undefined_trap_on_error.  If 2 sanitizers are involved
        and flag_sanitize_trap differs for them, emit __builtin_trap only
        for the comparison where trap is requested.
        (ubsan_instrument_vla, ubsan_instrument_return): Use
        lag_sanitize_trap & SANITIZE_??? instead of
        flag_sanitize_undefined_trap_on_error.
gcc/cp/
        * cp-ubsan.cc (cp_ubsan_instrument_vptr_p): Use
        flag_sanitize_trap & SANITIZE_VPTR instead of
        flag_sanitize_undefined_trap_on_error.
gcc/testsuite/
        * c-c++-common/ubsan/nonnull-4.c: Use -fsanitize-trap=all
        instead of -fsanitize-undefined-trap-on-error.
        * c-c++-common/ubsan/div-by-zero-4.c: Use
        -fsanitize-trap=signed-integer-overflow instead of
        -fsanitize-undefined-trap-on-error.
        * c-c++-common/ubsan/overflow-add-4.c: Use -fsanitize-trap=undefined
        instead of -fsanitize-undefined-trap-on-error.
        * c-c++-common/ubsan/pr56956.c: Likewise.
        * c-c++-common/ubsan/pr68142.c: Likewise.
        * c-c++-common/ubsan/pr80932.c: Use
        -fno-sanitize-trap=all -fsanitize-trap=shift,undefined
        instead of -fsanitize-undefined-trap-on-error.
        * c-c++-common/ubsan/align-8.c: Use -fsanitize-trap=alignment
        instead of -fsanitize-undefined-trap-on-error.

--- gcc/common.opt.jj   2022-06-13 14:02:29.532643844 +0200
+++ gcc/common.opt      2022-06-17 15:24:18.950562715 +0200
@@ -223,6 +223,10 @@ unsigned int flag_sanitize
 Variable
 unsigned int flag_sanitize_recover = (SANITIZE_UNDEFINED | 
SANITIZE_UNDEFINED_NONDEFAULT | SANITIZE_KERNEL_ADDRESS | 
SANITIZE_KERNEL_HWADDRESS) & ~(SANITIZE_UNREACHABLE | SANITIZE_RETURN)
 
+; What sanitizers should use __builtin_trap () instead of runtime diagnostics
+Variable
+unsigned int flag_sanitize_trap
+
 ; Flag whether a prefix has been added to dump_base_name
 Variable
 bool dump_base_name_prefixed = false
@@ -1105,12 +1109,19 @@ fsanitize-recover
 Common
 This switch is deprecated; use -fsanitize-recover= instead.
 
+fsanitize-trap=
+Common Driver Joined
+Use traps instead of diagnostics of undefined behavior sanitizers.
+
+fsanitize-trap
+Common Driver
+
 fsanitize-address-use-after-scope
 Common Driver Var(flag_sanitize_address_use_after_scope) Init(0)
 
 fsanitize-undefined-trap-on-error
-Common Driver Var(flag_sanitize_undefined_trap_on_error) Init(0)
-Use trap instead of a library function for undefined behavior sanitization.
+Common Driver Alias(fsanitize-trap)
+This switch is deprecated; use -fsanitize-trap= instead.
 
 fasynchronous-unwind-tables
 Common Var(flag_asynchronous_unwind_tables) Optimization
--- gcc/opts.h.jj       2022-02-04 14:36:55.456599000 +0100
+++ gcc/opts.h  2022-06-17 11:43:22.131670515 +0200
@@ -473,6 +473,7 @@ extern const struct sanitizer_opts_s
   unsigned int flag;
   size_t len;
   bool can_recover;
+  bool can_trap;
 } sanitizer_opts[];
 
 extern const struct zero_call_used_regs_opts_s
--- gcc/opts.cc.jj      2022-06-17 11:08:11.875492903 +0200
+++ gcc/opts.cc 2022-06-17 15:43:20.424343087 +0200
@@ -1232,6 +1232,18 @@ finish_options (struct gcc_options *opts
       error_at (loc, "%<-fsanitize-recover=%s%> is not supported",
                sanitizer_opts[i].name);
 
+  /* Check -fsanitize-trap option.  */
+  for (int i = 0; sanitizer_opts[i].name != NULL; ++i)
+    if ((opts->x_flag_sanitize_trap & sanitizer_opts[i].flag)
+       && !sanitizer_opts[i].can_trap
+       /* Allow -fsanitize-trap=all or -fsanitize-trap=undefined
+          to set flag_sanitize_trap & SANITIZE_VPTR bit which will
+          effectively disable -fsanitize=vptr, just disallow
+          explicit -fsanitize-trap=vptr.  */
+       && sanitizer_opts[i].flag != SANITIZE_VPTR)
+      error_at (loc, "%<-fsanitize-trap=%s%> is not supported",
+               sanitizer_opts[i].name);
+
   /* When instrumenting the pointers, we don't want to remove
      the null pointer checks.  */
   if (opts->x_flag_sanitize & (SANITIZE_NULL | SANITIZE_NONNULL_ATTRIBUTE
@@ -2020,48 +2032,50 @@ enable_fdo_optimizations (struct gcc_opt
 /* -f{,no-}sanitize{,-recover}= suboptions.  */
 const struct sanitizer_opts_s sanitizer_opts[] =
 {
-#define SANITIZER_OPT(name, flags, recover) \
-    { #name, flags, sizeof #name - 1, recover }
-  SANITIZER_OPT (address, (SANITIZE_ADDRESS | SANITIZE_USER_ADDRESS), true),
+#define SANITIZER_OPT(name, flags, recover, trap) \
+    { #name, flags, sizeof #name - 1, recover, trap }
+  SANITIZER_OPT (address, (SANITIZE_ADDRESS | SANITIZE_USER_ADDRESS), true,
+                false),
   SANITIZER_OPT (hwaddress, (SANITIZE_HWADDRESS | SANITIZE_USER_HWADDRESS),
-                true),
+                true, false),
   SANITIZER_OPT (kernel-address, (SANITIZE_ADDRESS | SANITIZE_KERNEL_ADDRESS),
-                true),
+                true, false),
   SANITIZER_OPT (kernel-hwaddress,
                 (SANITIZE_HWADDRESS | SANITIZE_KERNEL_HWADDRESS),
+                true, false),
+  SANITIZER_OPT (pointer-compare, SANITIZE_POINTER_COMPARE, true, false),
+  SANITIZER_OPT (pointer-subtract, SANITIZE_POINTER_SUBTRACT, true, false),
+  SANITIZER_OPT (thread, SANITIZE_THREAD, false, false),
+  SANITIZER_OPT (leak, SANITIZE_LEAK, false, false),
+  SANITIZER_OPT (shift, SANITIZE_SHIFT, true, true),
+  SANITIZER_OPT (shift-base, SANITIZE_SHIFT_BASE, true, true),
+  SANITIZER_OPT (shift-exponent, SANITIZE_SHIFT_EXPONENT, true, true),
+  SANITIZER_OPT (integer-divide-by-zero, SANITIZE_DIVIDE, true, true),
+  SANITIZER_OPT (undefined, SANITIZE_UNDEFINED, true, true),
+  SANITIZER_OPT (unreachable, SANITIZE_UNREACHABLE, false, true),
+  SANITIZER_OPT (vla-bound, SANITIZE_VLA, true, true),
+  SANITIZER_OPT (return, SANITIZE_RETURN, false, true),
+  SANITIZER_OPT (null, SANITIZE_NULL, true, true),
+  SANITIZER_OPT (signed-integer-overflow, SANITIZE_SI_OVERFLOW, true, true),
+  SANITIZER_OPT (bool, SANITIZE_BOOL, true, true),
+  SANITIZER_OPT (enum, SANITIZE_ENUM, true, true),
+  SANITIZER_OPT (float-divide-by-zero, SANITIZE_FLOAT_DIVIDE, true, true),
+  SANITIZER_OPT (float-cast-overflow, SANITIZE_FLOAT_CAST, true, true),
+  SANITIZER_OPT (bounds, SANITIZE_BOUNDS, true, true),
+  SANITIZER_OPT (bounds-strict, SANITIZE_BOUNDS | SANITIZE_BOUNDS_STRICT, true,
                 true),
-  SANITIZER_OPT (pointer-compare, SANITIZE_POINTER_COMPARE, true),
-  SANITIZER_OPT (pointer-subtract, SANITIZE_POINTER_SUBTRACT, true),
-  SANITIZER_OPT (thread, SANITIZE_THREAD, false),
-  SANITIZER_OPT (leak, SANITIZE_LEAK, false),
-  SANITIZER_OPT (shift, SANITIZE_SHIFT, true),
-  SANITIZER_OPT (shift-base, SANITIZE_SHIFT_BASE, true),
-  SANITIZER_OPT (shift-exponent, SANITIZE_SHIFT_EXPONENT, true),
-  SANITIZER_OPT (integer-divide-by-zero, SANITIZE_DIVIDE, true),
-  SANITIZER_OPT (undefined, SANITIZE_UNDEFINED, true),
-  SANITIZER_OPT (unreachable, SANITIZE_UNREACHABLE, false),
-  SANITIZER_OPT (vla-bound, SANITIZE_VLA, true),
-  SANITIZER_OPT (return, SANITIZE_RETURN, false),
-  SANITIZER_OPT (null, SANITIZE_NULL, true),
-  SANITIZER_OPT (signed-integer-overflow, SANITIZE_SI_OVERFLOW, true),
-  SANITIZER_OPT (bool, SANITIZE_BOOL, true),
-  SANITIZER_OPT (enum, SANITIZE_ENUM, true),
-  SANITIZER_OPT (float-divide-by-zero, SANITIZE_FLOAT_DIVIDE, true),
-  SANITIZER_OPT (float-cast-overflow, SANITIZE_FLOAT_CAST, true),
-  SANITIZER_OPT (bounds, SANITIZE_BOUNDS, true),
-  SANITIZER_OPT (bounds-strict, SANITIZE_BOUNDS | SANITIZE_BOUNDS_STRICT, 
true),
-  SANITIZER_OPT (alignment, SANITIZE_ALIGNMENT, true),
-  SANITIZER_OPT (nonnull-attribute, SANITIZE_NONNULL_ATTRIBUTE, true),
+  SANITIZER_OPT (alignment, SANITIZE_ALIGNMENT, true, true),
+  SANITIZER_OPT (nonnull-attribute, SANITIZE_NONNULL_ATTRIBUTE, true, true),
   SANITIZER_OPT (returns-nonnull-attribute, SANITIZE_RETURNS_NONNULL_ATTRIBUTE,
-                true),
-  SANITIZER_OPT (object-size, SANITIZE_OBJECT_SIZE, true),
-  SANITIZER_OPT (vptr, SANITIZE_VPTR, true),
-  SANITIZER_OPT (pointer-overflow, SANITIZE_POINTER_OVERFLOW, true),
-  SANITIZER_OPT (builtin, SANITIZE_BUILTIN, true),
-  SANITIZER_OPT (shadow-call-stack, SANITIZE_SHADOW_CALL_STACK, false),
-  SANITIZER_OPT (all, ~0U, true),
+                true, true),
+  SANITIZER_OPT (object-size, SANITIZE_OBJECT_SIZE, true, true),
+  SANITIZER_OPT (vptr, SANITIZE_VPTR, true, false),
+  SANITIZER_OPT (pointer-overflow, SANITIZE_POINTER_OVERFLOW, true, true),
+  SANITIZER_OPT (builtin, SANITIZE_BUILTIN, true, true),
+  SANITIZER_OPT (shadow-call-stack, SANITIZE_SHADOW_CALL_STACK, false, false),
+  SANITIZER_OPT (all, ~0U, true, true),
 #undef SANITIZER_OPT
-  { NULL, 0U, 0UL, false }
+  { NULL, 0U, 0UL, false, false }
 };
 
 /* -fzero-call-used-regs= suboptions.  */
@@ -2114,7 +2128,7 @@ struct edit_distance_traits<const string
 /* Given ARG, an unrecognized sanitizer option, return the best
    matching sanitizer option, or NULL if there isn't one.
    OPTS is array of candidate sanitizer options.
-   CODE is OPT_fsanitize_ or OPT_fsanitize_recover_.
+   CODE is OPT_fsanitize_, OPT_fsanitize_recover_ or OPT_fsanitize_trap_.
    VALUE is non-zero for the regular form of the option, zero
    for the "no-" form (e.g. "-fno-sanitize-recover=").  */
 
@@ -2139,6 +2153,13 @@ get_closest_sanitizer_option (const stri
          && value)
        continue;
 
+      /* For -fsanitize-trap= (and not -fno-sanitize-trap=),
+        don't offer the non-trapping options.  */
+      if (code == OPT_fsanitize_trap_
+         && !opts[i].can_trap
+         && value)
+       continue;
+
       bm.consider (opts[i].name);
     }
   return bm.get_best_meaningful_candidate ();
@@ -2183,10 +2204,13 @@ parse_sanitizer_options (const char *p,
                    if (complain)
                      error_at (loc, "%<-fsanitize=all%> option is not valid");
                  }
-               else
+               else if (code == OPT_fsanitize_recover_)
                  flags |= ~(SANITIZE_THREAD | SANITIZE_LEAK
                             | SANITIZE_UNREACHABLE | SANITIZE_RETURN
                             | SANITIZE_SHADOW_CALL_STACK);
+               else
+                 flags |= (SANITIZE_UNDEFINED
+                           | SANITIZE_UNDEFINED_NONDEFAULT);
              }
            else if (value)
              {
@@ -2197,6 +2221,10 @@ parse_sanitizer_options (const char *p,
                    && sanitizer_opts[i].flag == SANITIZE_UNDEFINED)
                  flags |= (SANITIZE_UNDEFINED
                            & ~(SANITIZE_UNREACHABLE | SANITIZE_RETURN));
+               else if (code == OPT_fsanitize_trap_
+                        && sanitizer_opts[i].flag == SANITIZE_VPTR)
+                 error_at (loc, "%<-fsanitize-trap=%s%> is not supported",
+                           sanitizer_opts[i].name);
                else
                  flags |= sanitizer_opts[i].flag;
              }
@@ -2215,6 +2243,8 @@ parse_sanitizer_options (const char *p,
          const char *suffix;
          if (code == OPT_fsanitize_recover_)
            suffix = "-recover";
+         else if (code == OPT_fsanitize_trap_)
+           suffix = "-trap";
          else
            suffix = "";
 
@@ -2647,6 +2677,12 @@ common_handle_option (struct gcc_options
                                   opts->x_flag_sanitize_recover, value, true);
       break;
 
+    case OPT_fsanitize_trap_:
+      opts->x_flag_sanitize_trap
+       = parse_sanitizer_options (arg, loc, code,
+                                  opts->x_flag_sanitize_trap, value, true);
+      break;
+
     case OPT_fasan_shadow_offset_:
       /* Deferred.  */
       break;
@@ -2665,6 +2701,15 @@ common_handle_option (struct gcc_options
          &= ~(SANITIZE_UNDEFINED | SANITIZE_UNDEFINED_NONDEFAULT);
       break;
 
+    case OPT_fsanitize_trap:
+      if (value)
+       opts->x_flag_sanitize_trap
+         |= (SANITIZE_UNDEFINED | SANITIZE_UNDEFINED_NONDEFAULT);
+      else
+       opts->x_flag_sanitize_trap
+         &= ~(SANITIZE_UNDEFINED | SANITIZE_UNDEFINED_NONDEFAULT);
+      break;
+
     case OPT_O:
     case OPT_Os:
     case OPT_Ofast:
--- gcc/sanopt.cc.jj    2022-01-18 11:58:59.886977714 +0100
+++ gcc/sanopt.cc       2022-06-17 14:07:18.021155983 +0200
@@ -392,11 +392,11 @@ maybe_optimize_ubsan_null_ifn (class san
      stmts have same location.  */
   else if (integer_zerop (align))
     remove = (flag_sanitize_recover & SANITIZE_NULL) == 0
-             || flag_sanitize_undefined_trap_on_error
+             || (flag_sanitize_trap & SANITIZE_NULL) != 0
              || gimple_location (g) == gimple_location (stmt);
   else if (tree_int_cst_le (cur_align, align))
     remove = (flag_sanitize_recover & SANITIZE_ALIGNMENT) == 0
-             || flag_sanitize_undefined_trap_on_error
+             || (flag_sanitize_trap & SANITIZE_ALIGNMENT) != 0
              || gimple_location (g) == gimple_location (stmt);
 
   if (!remove && gimple_bb (g) == gimple_bb (stmt)
--- gcc/gcc.cc.jj       2022-06-03 11:20:13.231070818 +0200
+++ gcc/gcc.cc  2022-06-17 13:34:16.482830857 +0200
@@ -10313,8 +10313,9 @@ sanitize_spec_function (int argc, const
     return (flag_sanitize & SANITIZE_THREAD) ? "" : NULL;
   if (strcmp (argv[0], "undefined") == 0)
     return ((flag_sanitize
-            & (SANITIZE_UNDEFINED | SANITIZE_UNDEFINED_NONDEFAULT))
-           && !flag_sanitize_undefined_trap_on_error) ? "" : NULL;
+            & ~flag_sanitize_trap
+            & (SANITIZE_UNDEFINED | SANITIZE_UNDEFINED_NONDEFAULT)))
+          ? "" : NULL;
   if (strcmp (argv[0], "leak") == 0)
     return ((flag_sanitize
             & (SANITIZE_ADDRESS | SANITIZE_LEAK | SANITIZE_THREAD))
--- gcc/ubsan.cc.jj     2022-05-13 09:34:24.043146671 +0200
+++ gcc/ubsan.cc        2022-06-17 14:14:42.164217896 +0200
@@ -647,7 +647,7 @@ ubsan_instrument_unreachable (gimple_stm
   gimple *g;
   location_t loc = gimple_location (gsi_stmt (*gsi));
 
-  if (flag_sanitize_undefined_trap_on_error)
+  if (flag_sanitize_trap & SANITIZE_UNREACHABLE)
     g = gimple_build_call (builtin_decl_explicit (BUILT_IN_TRAP), 0);
   else
     {
@@ -719,7 +719,7 @@ ubsan_expand_bounds_ifn (gimple_stmt_ite
 
   /* Generate __ubsan_handle_out_of_bounds call.  */
   *gsi = gsi_after_labels (then_bb);
-  if (flag_sanitize_undefined_trap_on_error)
+  if (flag_sanitize_trap & SANITIZE_BOUNDS)
     g = gimple_build_call (builtin_decl_explicit (BUILT_IN_TRAP), 0);
   else
     {
@@ -827,7 +827,8 @@ ubsan_expand_null_ifn (gimple_stmt_itera
     set_immediate_dominator (CDI_DOMINATORS, then_bb, cond_bb);
 
   /* Put the ubsan builtin call into the newly created BB.  */
-  if (flag_sanitize_undefined_trap_on_error)
+  if (flag_sanitize_trap & ((check_align ? SANITIZE_ALIGNMENT + 0 : 0)
+                           | (check_null ? SANITIZE_NULL + 0 : 0)))
     g = gimple_build_call (builtin_decl_implicit (BUILT_IN_TRAP), 0);
   else
     {
@@ -997,7 +998,7 @@ ubsan_expand_objsize_ifn (gimple_stmt_it
        }
 
       /* Generate __ubsan_handle_type_mismatch call.  */
-      if (flag_sanitize_undefined_trap_on_error)
+      if (flag_sanitize_trap & SANITIZE_OBJECT_SIZE)
        g = gimple_build_call (builtin_decl_explicit (BUILT_IN_TRAP), 0);
       else
        {
@@ -1143,7 +1144,7 @@ ubsan_expand_ptr_ifn (gimple_stmt_iterat
     }
 
   /* Put the ubsan builtin call into the newly created BB.  */
-  if (flag_sanitize_undefined_trap_on_error)
+  if (flag_sanitize_trap & SANITIZE_POINTER_OVERFLOW)
     g = gimple_build_call (builtin_decl_implicit (BUILT_IN_TRAP), 0);
   else
     {
@@ -1518,7 +1519,7 @@ tree
 ubsan_build_overflow_builtin (tree_code code, location_t loc, tree lhstype,
                              tree op0, tree op1, tree *datap)
 {
-  if (flag_sanitize_undefined_trap_on_error)
+  if (flag_sanitize_trap & SANITIZE_SI_OVERFLOW)
     return build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_TRAP), 0);
 
   tree data;
@@ -1741,7 +1742,8 @@ instrument_bool_enum_load (gimple_stmt_i
     }
 
   gsi2 = gsi_after_labels (then_bb);
-  if (flag_sanitize_undefined_trap_on_error)
+  if (flag_sanitize_trap & (TREE_CODE (type) == BOOLEAN_TYPE
+                           ? SANITIZE_BOOL : SANITIZE_ENUM))
     g = gimple_build_call (builtin_decl_explicit (BUILT_IN_TRAP), 0);
   else
     {
@@ -1904,7 +1906,7 @@ ubsan_instrument_float_cast (location_t
   if (integer_zerop (t))
     return NULL_TREE;
 
-  if (flag_sanitize_undefined_trap_on_error)
+  if (flag_sanitize_trap & SANITIZE_FLOAT_CAST)
     fn = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_TRAP), 0);
   else
     {
@@ -1974,7 +1976,7 @@ instrument_nonnull_arg (gimple_stmt_iter
          gsi_insert_after (gsi, g, GSI_NEW_STMT);
 
          *gsi = gsi_after_labels (then_bb);
-         if (flag_sanitize_undefined_trap_on_error)
+         if (flag_sanitize_trap & SANITIZE_NONNULL_ATTRIBUTE)
            g = gimple_build_call (builtin_decl_explicit (BUILT_IN_TRAP), 0);
          else
            {
@@ -2030,7 +2032,7 @@ instrument_nonnull_return (gimple_stmt_i
       gsi_insert_after (gsi, g, GSI_NEW_STMT);
 
       *gsi = gsi_after_labels (then_bb);
-      if (flag_sanitize_undefined_trap_on_error)
+      if (flag_sanitize_trap & SANITIZE_RETURNS_NONNULL_ATTRIBUTE)
        g = gimple_build_call (builtin_decl_explicit (BUILT_IN_TRAP), 0);
       else
        {
@@ -2279,7 +2281,7 @@ instrument_builtin (gimple_stmt_iterator
          gsi_insert_after (gsi, g, GSI_NEW_STMT);
 
          *gsi = gsi_after_labels (then_bb);
-         if (flag_sanitize_undefined_trap_on_error)
+         if (flag_sanitize_trap & SANITIZE_BUILTIN)
            g = gimple_build_call (builtin_decl_explicit (BUILT_IN_TRAP), 0);
          else
            {
--- gcc/doc/invoke.texi.jj      2022-06-16 10:56:28.826386840 +0200
+++ gcc/doc/invoke.texi 2022-06-17 16:42:59.370670655 +0200
@@ -609,6 +609,7 @@ Objective-C and Objective-C++ Dialects}.
 -fprofile-exclude-files=@var{regex} @gol
 -fprofile-reproducible=@r{[}multithreaded@r{|}parallel-runs@r{|}serial@r{]} 
@gol
 -fsanitize=@var{style}  -fsanitize-recover  -fsanitize-recover=@var{style} @gol
+-fsanitize-trap   -fsanitize-trap=@var{style}  @gol
 -fasan-shadow-offset=@var{number}  -fsanitize-sections=@var{s1},@var{s2},... 
@gol
 -fsanitize-undefined-trap-on-error  -fbounds-check @gol
 -fcf-protection=@r{[}full@r{|}branch@r{|}return@r{|}none@r{|}check@r{]} @gol
@@ -16116,13 +16117,37 @@ undefined,float-cast-overflow,float-divi
 Enable sanitization of local variables to detect use-after-scope bugs.
 The option sets @option{-fstack-reuse} to @samp{none}.
 
+@item -fsanitize-trap@r{[}=@var{opts}@r{]}
+@opindex fsanitize-trap
+@opindex fno-sanitize-trap
+The @option{-fsanitize-trap=} option instructs the compiler to
+report for sanitizers mentioned in comma-separated list of @var{opts}
+undefined behavior using @code{__builtin_trap} rather than a @code{libubsan}
+library routine.  If this option is enabled for certain sanitizer,
+it takes precedence over the @option{-fsanitizer-recover=} for that
+sanitizer, @code{__builtin_trap} will be emitted and be fatal regardless
+of whether recovery is enabled or disabled using @option{-fsanitize-recover=}.
+
+The advantage of this is that the @code{libubsan} library is not needed
+and is not linked in, so this is usable even in freestanding environments.
+
+Currently this feature works with @option{-fsanitize=undefined} (and its 
suboptions
+except for @option{-fsanitize=vptr}), @option{-fsanitize=float-cast-overflow},
+@option{-fsanitize=float-divide-by-zero} and
+@option{-fsanitize=bounds-strict}.  @code{-fsanitize-trap=all} can be also
+specified, which enables it for @code{undefined} suboptions,
+@option{-fsanitize=float-cast-overflow},
+@option{-fsanitize=float-divide-by-zero} and
+@option{-fsanitize=bounds-strict}.
+If @code{-fsanitize-trap=undefined} or @code{-fsanitize-trap=all} is used
+and @code{-fsanitize=vptr} is enabled on the command line, the
+instrumentation is silently ignored as the instrumentation always needs
+@code{libubsan} support, @option{-fsanitize-trap=vptr} is not allowed.
+
 @item -fsanitize-undefined-trap-on-error
 @opindex fsanitize-undefined-trap-on-error
-The @option{-fsanitize-undefined-trap-on-error} option instructs the compiler 
to
-report undefined behavior using @code{__builtin_trap} rather than
-a @code{libubsan} library routine.  The advantage of this is that the
-@code{libubsan} library is not needed and is not linked in, so this
-is usable even in freestanding environments.
+The @option{-fsanitize-undefined-trap-on-error} option is deprecated
+equivalent of @option{-fsanitize-trap=all}.
 
 @item -fsanitize-coverage=trace-pc
 @opindex fsanitize-coverage=trace-pc
--- gcc/c-family/c-ubsan.cc.jj  2022-06-14 13:17:01.559722905 +0200
+++ gcc/c-family/c-ubsan.cc     2022-06-17 15:23:16.899389988 +0200
@@ -83,8 +83,9 @@ ubsan_instrument_division (location_t lo
          x = NULL_TREE;
          flag = SANITIZE_SI_OVERFLOW;
        }
-      else if (flag_sanitize_undefined_trap_on_error
-              || (((flag_sanitize_recover & SANITIZE_DIVIDE) == 0)
+      else if ((((flag_sanitize_trap & SANITIZE_DIVIDE) == 0)
+               == ((flag_sanitize_trap & SANITIZE_SI_OVERFLOW) == 0))
+              && (((flag_sanitize_recover & SANITIZE_DIVIDE) == 0)
                   == ((flag_sanitize_recover & SANITIZE_SI_OVERFLOW) == 0)))
        {
          t = fold_build2 (TRUTH_OR_EXPR, boolean_type_node, t, x);
@@ -105,7 +106,7 @@ ubsan_instrument_division (location_t lo
      make sure it gets evaluated before the condition.  */
   t = fold_build2 (COMPOUND_EXPR, TREE_TYPE (t), unshare_expr (op0), t);
   t = fold_build2 (COMPOUND_EXPR, TREE_TYPE (t), unshare_expr (op1), t);
-  if (flag_sanitize_undefined_trap_on_error)
+  if ((flag_sanitize_trap & flag) && x == NULL_TREE)
     tt = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_TRAP), 0);
   else
     {
@@ -113,25 +114,41 @@ ubsan_instrument_division (location_t lo
                                     ubsan_type_descriptor (type), NULL_TREE,
                                     NULL_TREE);
       data = build_fold_addr_expr_loc (loc, data);
-      enum built_in_function bcode
-       = (flag_sanitize_recover & flag)
-         ? BUILT_IN_UBSAN_HANDLE_DIVREM_OVERFLOW
-         : BUILT_IN_UBSAN_HANDLE_DIVREM_OVERFLOW_ABORT;
-      tt = builtin_decl_explicit (bcode);
-      op0 = unshare_expr (op0);
-      op1 = unshare_expr (op1);
-      tt = build_call_expr_loc (loc, tt, 3, data, ubsan_encode_value (op0),
-                               ubsan_encode_value (op1));
-      if (x)
+      if (flag_sanitize_trap & flag)
+       tt = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_TRAP),
+                                 0);
+      else
        {
-         bcode = (flag_sanitize_recover & SANITIZE_SI_OVERFLOW)
-                 ? BUILT_IN_UBSAN_HANDLE_DIVREM_OVERFLOW
-                 : BUILT_IN_UBSAN_HANDLE_DIVREM_OVERFLOW_ABORT;
-         tree xt = builtin_decl_explicit (bcode);
+         enum built_in_function bcode
+           = (flag_sanitize_recover & flag)
+             ? BUILT_IN_UBSAN_HANDLE_DIVREM_OVERFLOW
+             : BUILT_IN_UBSAN_HANDLE_DIVREM_OVERFLOW_ABORT;
+         tt = builtin_decl_explicit (bcode);
          op0 = unshare_expr (op0);
          op1 = unshare_expr (op1);
-         xt = build_call_expr_loc (loc, xt, 3, data, ubsan_encode_value (op0),
+         tt = build_call_expr_loc (loc, tt, 3, data, ubsan_encode_value (op0),
                                    ubsan_encode_value (op1));
+       }
+      if (x)
+       {
+         tree xt;
+         if (flag_sanitize_trap & SANITIZE_SI_OVERFLOW)
+           xt = build_call_expr_loc (loc,
+                                     builtin_decl_explicit (BUILT_IN_TRAP),
+                                     0);
+         else
+           {
+             enum built_in_function bcode
+               = (flag_sanitize_recover & SANITIZE_SI_OVERFLOW)
+                  ? BUILT_IN_UBSAN_HANDLE_DIVREM_OVERFLOW
+                  : BUILT_IN_UBSAN_HANDLE_DIVREM_OVERFLOW_ABORT;
+             xt = builtin_decl_explicit (bcode);
+             op0 = unshare_expr (op0);
+             op1 = unshare_expr (op1);
+             xt = build_call_expr_loc (loc, xt, 3, data,
+                                       ubsan_encode_value (op0),
+                                       ubsan_encode_value (op1));
+           }
          x = fold_build3 (COND_EXPR, void_type_node, x, xt, void_node);
        }
     }
@@ -225,8 +242,9 @@ ubsan_instrument_shift (location_t loc,
        }
       else
        {
-         if (flag_sanitize_undefined_trap_on_error
-             || ((!(flag_sanitize_recover & SANITIZE_SHIFT_EXPONENT))
+         if (((!(flag_sanitize_trap & SANITIZE_SHIFT_EXPONENT))
+              == (!(flag_sanitize_trap & SANITIZE_SHIFT_BASE)))
+             && ((!(flag_sanitize_recover & SANITIZE_SHIFT_EXPONENT))
                  == (!(flag_sanitize_recover & SANITIZE_SHIFT_BASE))))
            t = fold_build2 (TRUTH_OR_EXPR, boolean_type_node, t, tt);
          else
@@ -234,7 +252,7 @@ ubsan_instrument_shift (location_t loc,
        }
     }
 
-  if (flag_sanitize_undefined_trap_on_error)
+  if ((flag_sanitize_trap & recover_kind) && else_t == void_node)
     tt = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_TRAP), 0);
   else
     {
@@ -244,26 +262,40 @@ ubsan_instrument_shift (location_t loc,
                                     NULL_TREE);
       data = build_fold_addr_expr_loc (loc, data);
 
-      enum built_in_function bcode
-       = (flag_sanitize_recover & recover_kind)
-         ? BUILT_IN_UBSAN_HANDLE_SHIFT_OUT_OF_BOUNDS
-         : BUILT_IN_UBSAN_HANDLE_SHIFT_OUT_OF_BOUNDS_ABORT;
-      tt = builtin_decl_explicit (bcode);
-      op0 = unshare_expr (op0);
-      op1 = unshare_expr (op1);
-      tt = build_call_expr_loc (loc, tt, 3, data, ubsan_encode_value (op0),
-                               ubsan_encode_value (op1));
+      if (flag_sanitize_trap & recover_kind)
+       tt = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_TRAP), 
0);
+      else
+       {
+         enum built_in_function bcode
+           = (flag_sanitize_recover & recover_kind)
+             ? BUILT_IN_UBSAN_HANDLE_SHIFT_OUT_OF_BOUNDS
+             : BUILT_IN_UBSAN_HANDLE_SHIFT_OUT_OF_BOUNDS_ABORT;
+         tt = builtin_decl_explicit (bcode);
+         op0 = unshare_expr (op0);
+         op1 = unshare_expr (op1);
+         tt = build_call_expr_loc (loc, tt, 3, data, ubsan_encode_value (op0),
+                                   ubsan_encode_value (op1));
+       }
       if (else_t != void_node)
        {
-         bcode = (flag_sanitize_recover & SANITIZE_SHIFT_BASE)
+         tree else_tt;
+         if (flag_sanitize_trap & SANITIZE_SHIFT_BASE)
+           else_tt
+             = build_call_expr_loc (loc,
+                                    builtin_decl_explicit (BUILT_IN_TRAP), 0);
+         else
+           {
+             enum built_in_function bcode
+               = (flag_sanitize_recover & SANITIZE_SHIFT_BASE)
                  ? BUILT_IN_UBSAN_HANDLE_SHIFT_OUT_OF_BOUNDS
                  : BUILT_IN_UBSAN_HANDLE_SHIFT_OUT_OF_BOUNDS_ABORT;
-         tree else_tt = builtin_decl_explicit (bcode);
-         op0 = unshare_expr (op0);
-         op1 = unshare_expr (op1);
-         else_tt = build_call_expr_loc (loc, else_tt, 3, data,
-                                        ubsan_encode_value (op0),
-                                        ubsan_encode_value (op1));
+             else_tt = builtin_decl_explicit (bcode);
+             op0 = unshare_expr (op0);
+             op1 = unshare_expr (op1);
+             else_tt = build_call_expr_loc (loc, else_tt, 3, data,
+                                            ubsan_encode_value (op0),
+                                            ubsan_encode_value (op1));
+           }
          else_t = fold_build3 (COND_EXPR, void_type_node, else_t,
                                else_tt, void_node);
        }
@@ -282,7 +314,7 @@ ubsan_instrument_vla (location_t loc, tr
   tree t, tt;
 
   t = fold_build2 (LE_EXPR, boolean_type_node, size, build_int_cst (type, 0));
-  if (flag_sanitize_undefined_trap_on_error)
+  if (flag_sanitize_trap & SANITIZE_VLA)
     tt = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_TRAP), 0);
   else
     {
@@ -307,10 +339,10 @@ ubsan_instrument_vla (location_t loc, tr
 tree
 ubsan_instrument_return (location_t loc)
 {
-  if (flag_sanitize_undefined_trap_on_error)
-    return build_call_expr_loc
-      /* pass_warn_function_return checks for BUILTINS_LOCATION.  */
-      (BUILTINS_LOCATION, builtin_decl_explicit (BUILT_IN_TRAP), 0);
+  if (flag_sanitize_trap & SANITIZE_RETURN)
+    /* pass_warn_function_return checks for BUILTINS_LOCATION.  */
+    return build_call_expr_loc (BUILTINS_LOCATION,
+                               builtin_decl_explicit (BUILT_IN_TRAP), 0);
 
   tree data = ubsan_create_data ("__ubsan_missing_return_data", 1, &loc,
                                 NULL_TREE, NULL_TREE);
--- gcc/cp/cp-ubsan.cc.jj       2022-01-18 11:58:59.299986100 +0100
+++ gcc/cp/cp-ubsan.cc  2022-06-17 15:14:01.760791859 +0200
@@ -32,7 +32,7 @@ along with GCC; see the file COPYING3.
 static bool
 cp_ubsan_instrument_vptr_p (tree type)
 {
-  if (!flag_rtti || flag_sanitize_undefined_trap_on_error)
+  if (!flag_rtti || (flag_sanitize_trap & SANITIZE_VPTR))
     return false;
 
   if (!sanitize_flags_p (SANITIZE_VPTR))
--- gcc/testsuite/c-c++-common/ubsan/nonnull-4.c.jj     2020-01-12 
11:54:37.029404115 +0100
+++ gcc/testsuite/c-c++-common/ubsan/nonnull-4.c        2022-06-17 
16:53:38.976152460 +0200
@@ -1,6 +1,6 @@
 /* { dg-do run } */
 /* { dg-shouldfail "ubsan" } */
-/* { dg-options "-fsanitize=undefined -fsanitize-undefined-trap-on-error" } */
+/* { dg-options "-fsanitize=undefined -fsanitize-trap=all" } */
 
 int q, r;
 void *a, *b, *c = (void *) &q, *d, *e, *f = (void *) &q, *g, *h;
--- gcc/testsuite/c-c++-common/ubsan/div-by-zero-4.c.jj 2021-12-30 
15:12:43.248150079 +0100
+++ gcc/testsuite/c-c++-common/ubsan/div-by-zero-4.c    2022-06-17 
16:53:02.139643041 +0200
@@ -1,5 +1,5 @@
 /* { dg-do run } */
-/* { dg-options "-fsanitize=signed-integer-overflow 
-fsanitize-undefined-trap-on-error -Wno-overflow" } */
+/* { dg-options "-fsanitize=signed-integer-overflow 
-fsanitize-trap=signed-integer-overflow -Wno-overflow" } */
 
 #define INT_MIN (-__INT_MAX__ - 1)
 
--- gcc/testsuite/c-c++-common/ubsan/overflow-add-4.c.jj        2020-01-12 
11:54:37.030404100 +0100
+++ gcc/testsuite/c-c++-common/ubsan/overflow-add-4.c   2022-06-17 
16:54:12.544705407 +0200
@@ -1,5 +1,5 @@
 /* { dg-do run } */
-/* { dg-options "-fsanitize=signed-integer-overflow -Wno-unused-variable 
-fsanitize-undefined-trap-on-error" } */
+/* { dg-options "-fsanitize=signed-integer-overflow -Wno-unused-variable 
-fsanitize-trap=undefined" } */
 /* { dg-shouldfail "ubsan" } */
 
 #define INT_MAX __INT_MAX__
--- gcc/testsuite/c-c++-common/ubsan/pr56956.c.jj       2020-01-12 
11:54:37.031404085 +0100
+++ gcc/testsuite/c-c++-common/ubsan/pr56956.c  2022-06-17 16:54:35.557398933 
+0200
@@ -1,5 +1,5 @@
 /* { dg-do run } */
-/* { dg-options "-fsanitize=undefined -fsanitize-undefined-trap-on-error" } */
+/* { dg-options "-fsanitize=undefined -fsanitize-trap=undefined" } */
 
 unsigned int __attribute__((noinline,noclone))
 foo (unsigned int x)
--- gcc/testsuite/c-c++-common/ubsan/pr68142.c.jj       2020-01-12 
11:54:37.031404085 +0100
+++ gcc/testsuite/c-c++-common/ubsan/pr68142.c  2022-06-17 16:55:02.426041091 
+0200
@@ -1,5 +1,5 @@
 /* { dg-do run } */
-/* { dg-options "-fsanitize=undefined -fsanitize-undefined-trap-on-error" } */
+/* { dg-options "-fsanitize=undefined -fsanitize-trap=undefined" } */
 
 int __attribute__((noinline,noclone))
 h(int a)
--- gcc/testsuite/c-c++-common/ubsan/pr80932.c.jj       2020-01-12 
11:54:37.032404070 +0100
+++ gcc/testsuite/c-c++-common/ubsan/pr80932.c  2022-06-17 16:55:59.401282322 
+0200
@@ -1,6 +1,6 @@
 /* PR sanitizer/80932 */
 /* { dg-do run } */
-/* { dg-options "-fsanitize=undefined -fsanitize-undefined-trap-on-error" } */
+/* { dg-options "-fsanitize=undefined -fno-sanitize-trap=all 
-fsanitize-trap=shift,undefined" } */
 
 int x = 1;
 
--- gcc/testsuite/c-c++-common/ubsan/align-8.c.jj       2020-01-12 
11:54:37.028404130 +0100
+++ gcc/testsuite/c-c++-common/ubsan/align-8.c  2022-06-17 16:50:57.827298591 
+0200
@@ -1,6 +1,6 @@
 /* Limit this to known non-strict alignment targets.  */
 /* { dg-do run { target { i?86-*-linux* x86_64-*-linux* } } } */
-/* { dg-options "-O -fsanitize=alignment -fsanitize-undefined-trap-on-error 
-Wno-address-of-packed-member -fdump-tree-sanopt-details" } */
+/* { dg-options "-O -fsanitize=alignment -fsanitize-trap=alignment 
-Wno-address-of-packed-member -fdump-tree-sanopt-details" } */
 /* { dg-skip-if "" { *-*-* } { "-flto -fno-fat-lto-objects" } } */
 /* { dg-shouldfail "ubsan" } */
 


        Jakub

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