[Bug c++/115913] New: ICE with pragma GCC pop_options (‘global_options’ are modified in local context)

[Bug c++/115913] New: ICE with pragma GCC pop_options (‘global_options’ are modified in local context)

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115913

            Bug ID: 115913
           Summary: ICE with pragma GCC pop_options (‘global_options’ are
                    modified in local context)
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sjames at gcc dot gnu.org
  Target Milestone: ---

Created attachment 58655
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58655&action=edit
hb-subset.cc.ii.xz

Hit this when bisecting via pragmas for PR115912.

```
$ gcc -c ./src/libharfbuzz-subset.so.0.60900.0.p/hb-subset.cc.ii
../src/hb-subset.cc:708:9: internal compiler error: ‘global_options’ are
modified in local context
  708 | #pragma GCC pop_options
      |         ^~~
0x56514e60db73 internal_error(char const*, ...)
       
/usr/src/debug/sys-devel/gcc-15.0.9999/gcc-15.0.9999/gcc/diagnostic-global-context.cc:491
0x56514d0b4545 cl_optimization_compare(gcc_options*, gcc_options*)
        /usr/src/debug/sys-devel/gcc-15.0.9999/build/gcc/options-save.cc:14248
0x56514f0ac0a4 handle_pragma_pop_options
       
/usr/src/debug/sys-devel/gcc-15.0.9999/gcc-15.0.9999/gcc/c-family/c-pragma.cc:1284
0x56514f061f17 cp_lexer_handle_early_pragma
       
/usr/src/debug/sys-devel/gcc-15.0.9999/gcc-15.0.9999/gcc/cp/parser.cc:700
0x56514f061f17 cp_lexer_new_main
       
/usr/src/debug/sys-devel/gcc-15.0.9999/gcc-15.0.9999/gcc/cp/parser.cc:747
0x56514f061f17 c_parse_file()
       
/usr/src/debug/sys-devel/gcc-15.0.9999/gcc-15.0.9999/gcc/cp/parser.cc:51760
0x56514f03019b c_common_parse_file()
       
/usr/src/debug/sys-devel/gcc-15.0.9999/gcc-15.0.9999/gcc/c-family/c-opts.cc:1315
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://bugs.gentoo.org/> for instructions.
```

[Bug c++/115913] ICE with pragma GCC pop_options (‘global_options’ are modified in local context)

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115913

--- Comment #1 from Sam James <sjames at gcc dot gnu.org> ---
It was fine until I moved the push_options+optimize above the include block.

[Bug c++/115913] ICE with pragma GCC pop_options (‘global_options’ are modified in local context)

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115913

--- Comment #2 from Sam James <sjames at gcc dot gnu.org> ---
Surrounding hb.hh does it, which makes sense given how much pragma fun it does:
https://github.com/harfbuzz/harfbuzz/blob/main/src/hb.hh.

[Bug middle-end/115913] ICE with pragma GCC pop_options (‘global_options’ are modified in local context)

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115913

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c++                         |middle-end
             Target|                            |x86_64

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This might be a target issue or a middle-end issue. Doubt it is a C++ front-end
issue.

[Bug middle-end/115913] ICE with pragma GCC pop_options (‘global_options’ are modified in local context)

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115913

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
```
#pragma GCC push_options
#pragma GCC diagnostic warning "-Wundef"
#pragma GCC pop_options
```

[Bug middle-end/115913] [11/12/13/14/15 Regression] ICE with pragma GCC pop_options with diagnostic

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115913

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |10.1.0, 10.5.0
            Summary|ICE with pragma GCC         |[11/12/13/14/15 Regression]
                   |pop_options                 |ICE with pragma GCC
                   |(‘global_options’ are       |pop_options with diagnostic
                   |modified in local context)  |
   Target Milestone|---                         |15.0

[Bug middle-end/115913] [11/12/13/14/15 Regression] ICE with pragma GCC pop_options with diagnostic

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115913

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2024-07-14

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
confirmed.

[Bug middle-end/115913] [11/12/13/14/15 Regression] ICE with pragma GCC pop_options with diagnostic

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115913

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|15.0                        |11.5

[Bug middle-end/115913] [11/12/13/14/15 Regression] ICE with pragma GCC pop_options with diagnostic since r11-1141

[lhyatt at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115913

Lewis Hyatt <lhyatt at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |lhyatt at gcc dot gnu.org,
                   |                            |marxin at gcc dot gnu.org
            Summary|[11/12/13/14/15 Regression] |[11/12/13/14/15 Regression]
                   |ICE with pragma GCC         |ICE with pragma GCC
                   |pop_options with diagnostic |pop_options with diagnostic
                   |                            |since r11-1141
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=92860

--- Comment #6 from Lewis Hyatt <lhyatt at gcc dot gnu.org> ---
Started with r11-1141 (which added the checking assert in the first place). I
think this check is ensuring that after this sequence:

#pragma GCC push_options
#pragma GCC optimize ...
#pragma GCC pop_options

all the options have been restored to their previous values. But it doesn't
consider that the options might have been deliberately changed by another
pragma, in which case they are not expected to retain their previous values.

I think the fix in the spirit of this check is to disable the check while a
diagnostic pragma is in force. This untested patch resolves it that way, if the
approach seems reasonable I could prepare it?

diff --git a/gcc/c-family/c-pragma.cc b/gcc/c-family/c-pragma.cc
index 25251c2b69f..0080bac99bf 100644
--- a/gcc/c-family/c-pragma.cc
+++ b/gcc/c-family/c-pragma.cc
@@ -866,6 +866,9 @@ pragma_diagnostic_lex (pragma_diagnostic_data *result)
   result->valid = true;
 }

+static void
+options_stack_disable_checking ();
+
 /* Handle #pragma GCC diagnostic.  Early mode is used by frontends (such as
C++)
    that do not process the deferred pragma while they are consuming tokens;
they
    can use early mode to make sure diagnostics affecting the preprocessor
itself
@@ -1020,6 +1023,7 @@ handle_pragma_diagnostic_impl ()
                          input_location, lang_mask, &handlers,
                          &global_options, &global_options_set,
                          global_dc);
+  options_stack_disable_checking ();
 }

 static void
@@ -1192,10 +1196,18 @@ struct GTY(()) opt_stack {
   tree optimize_binary;
   tree optimize_strings;
   gcc_options * GTY ((skip)) saved_global_options;
+  bool disable_checking;
 };

 static GTY(()) struct opt_stack * options_stack;

+static void
+options_stack_disable_checking ()
+{
+  if (options_stack)
+    options_stack->disable_checking = true;
+}
+
 /* Handle #pragma GCC push_options to save the current target and optimization
    options.  */

@@ -1212,7 +1224,7 @@ handle_pragma_push_options (cpp_reader *)
       return;
     }

-  opt_stack *p = ggc_alloc<opt_stack> ();
+  opt_stack *p = ggc_cleared_alloc<opt_stack> ();
   p->prev = options_stack;
   options_stack = p;

@@ -1260,6 +1272,14 @@ handle_pragma_pop_options (cpp_reader *)
   p = options_stack;
   options_stack = p->prev;

+  if (flag_checking && p->disable_checking)
+    {
+      XDELETEVEC (p->saved_global_options);
+      p->saved_global_options = nullptr;
+      if (p->prev)
+       p->prev->disable_checking = true;
+    }
+
   if (p->target_binary != target_option_current_node)
     {
       (void) targetm.target_option.pragma_parse (NULL_TREE, p->target_binary);
@@ -1279,7 +1299,7 @@ handle_pragma_pop_options (cpp_reader *)
                                      p->optimize_binary);
       optimization_current_node = p->optimize_binary;
     }
-  if (flag_checking && !seen_error ())
+  if (flag_checking && p->saved_global_options && !seen_error ())
     {
       cl_optimization_compare (p->saved_global_options, &global_options);
       free (p->saved_global_options);

[Bug middle-end/115913] [11/12/13/14/15 Regression] ICE with pragma GCC pop_options with diagnostic since r11-1141

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115913

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The bigger question should `GCC pop_options` also pop the diagnostic option
changes too? or is that only done with `GCC diagnostic pop`.

[Bug middle-end/115913] [11/12/13/14/15 Regression] ICE with pragma GCC pop_options with diagnostic since r11-1141

[lhyatt at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115913

--- Comment #8 from Lewis Hyatt <lhyatt at gcc dot gnu.org> ---
I think they are for different things, push_options/pop_options is for saving
and restoring the command line flags that get implied from switching
optimization levels or target pragmas, while diagnostic pragmas are for turning
and and off warnings flags. So I guess another alternative to the patch I
posted would be, #pragma GCC pop_options could ignore all warnings-related
options when doing its checking? I'm not sure if it was intentional that it
wanted to check those or not.

[Bug middle-end/115913] [12/13/14/15 Regression] ICE with pragma GCC pop_options with diagnostic since r11-1141

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115913

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|11.5                        |12.5

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 11 branch is being closed.