[PING] Re: [PATCH] analyzer: deal with -fshort-enums

[Torbjorn SVENSSON <torbjorn.svensson@foss.st.com>]

Ping!

Kind regards,
Torbjörn

On 2024-02-07 17:21, Torbjorn SVENSSON wrote:
> Hi,
> 
> Is it okay to backport 3cbab07b08d2f3a3ed34b6ec12e67727c59d285c to 
> releases/gcc-13?
> 
> Without this backport, I see these failures on arm-none-eabi:
> 
> FAIL: gcc.dg/analyzer/switch-enum-1.c  (test for bogus messages, line 26)
> FAIL: gcc.dg/analyzer/switch-enum-1.c  (test for bogus messages, line 44)
> FAIL: gcc.dg/analyzer/switch-enum-2.c  (test for bogus messages, line 34)
> FAIL: gcc.dg/analyzer/switch-enum-2.c  (test for bogus messages, line 52)
> FAIL: gcc.dg/analyzer/torture/switch-enum-pr105273-doom-p_floor.c   -O0 
>   (test for bogus messages, line 82)
> FAIL: gcc.dg/analyzer/torture/switch-enum-pr105273-doom-p_maputl.c   -O0 
>    (test for bogus messages, line 83)
> 
> Kind regards,
> Torbjörn
> 
> 
> On 2023-12-06 23:22, David Malcolm wrote:
>> On Wed, 2023-12-06 at 02:31 -0300, Alexandre Oliva wrote:
>>> On Nov 22, 2023, Alexandre Oliva <oliva@adacore.com> wrote:
>>>
>>>> Ah, nice, that's a great idea, I wish I'd thought of that!  Will
>>>> do.
>>>
>>> Sorry it took me so long, here it is.  I added two tests, so that,
>>> regardless of the defaults, we get both circumstances tested, without
>>> repetition.
>>>
>>> Regstrapped on x86_64-linux-gnu.  Also tested on arm-eabi.  Ok to
>>> install?
>>
>> Thanks for the updated patch.
>>
>> Looks good to me.
>>
>> Dave
>>
>>>
>>>
>>> analyzer: deal with -fshort-enums
>>>
>>> On platforms that enable -fshort-enums by default, various switch-
>>> enum
>>> analyzer tests fail, because apply_constraints_for_gswitch doesn't
>>> expect the integral promotion type cast.  I've arranged for the code
>>> to cope with those casts.
>>>
>>>
>>> for  gcc/analyzer/ChangeLog
>>>
>>>          * region-model.cc (has_nondefault_case_for_value_p): Take
>>>          enumerate type as a parameter.
>>>          (region_model::apply_constraints_for_gswitch): Cope with
>>>          integral promotion type casts.
>>>
>>> for  gcc/testsuite/ChangeLog
>>>
>>>          * gcc.dg/analyzer/switch-short-enum-1.c: New.
>>>          * gcc.dg/analyzer/switch-no-short-enum-1.c: New.
>>> ---
>>>   gcc/analyzer/region-model.cc                       |   27 +++-
>>>   .../gcc.dg/analyzer/switch-no-short-enum-1.c       |  141
>>> ++++++++++++++++++++
>>>   .../gcc.dg/analyzer/switch-short-enum-1.c          |  140
>>> ++++++++++++++++++++
>>>   3 files changed, 304 insertions(+), 4 deletions(-)
>>>   create mode 100644 gcc/testsuite/gcc.dg/analyzer/switch-no-short-
>>> enum-1.c
>>>   create mode 100644 gcc/testsuite/gcc.dg/analyzer/switch-short-enum-
>>> 1.c
>>>
>>> diff --git a/gcc/analyzer/region-model.cc b/gcc/analyzer/region-
>>> model.cc
>>> index 2157ad2578b85..6a7a8bc9f4884 100644
>>> --- a/gcc/analyzer/region-model.cc
>>> +++ b/gcc/analyzer/region-model.cc
>>> @@ -5387,10 +5387,10 @@ has_nondefault_case_for_value_p (const
>>> gswitch *switch_stmt, tree int_cst)
>>>      has nondefault cases handling all values in the enum.  */
>>>   static bool
>>> -has_nondefault_cases_for_all_enum_values_p (const gswitch
>>> *switch_stmt)
>>> +has_nondefault_cases_for_all_enum_values_p (const gswitch
>>> *switch_stmt,
>>> +                                           tree type)
>>>   {
>>>     gcc_assert (switch_stmt);
>>> -  tree type = TREE_TYPE (gimple_switch_index (switch_stmt));
>>>     gcc_assert (TREE_CODE (type) == ENUMERAL_TYPE);
>>>     for (tree enum_val_iter = TYPE_VALUES (type);
>>> @@ -5426,6 +5426,23 @@ apply_constraints_for_gswitch (const
>>> switch_cfg_superedge &edge,
>>>   {
>>>     tree index  = gimple_switch_index (switch_stmt);
>>>     const svalue *index_sval = get_rvalue (index, ctxt);
>>> +  bool check_index_type = true;
>>> +
>>> +  /* With -fshort-enum, there may be a type cast.  */
>>> +  if (ctxt && index_sval->get_kind () == SK_UNARYOP
>>> +      && TREE_CODE (index_sval->get_type ()) == INTEGER_TYPE)
>>> +    {
>>> +      const unaryop_svalue *unaryop = as_a <const unaryop_svalue *>
>>> (index_sval);
>>> +      if (unaryop->get_op () == NOP_EXPR
>>> +         && is_a <const initial_svalue *> (unaryop->get_arg ()))
>>> +       if (const initial_svalue *initvalop = (as_a <const
>>> initial_svalue *>
>>> +                                              (unaryop->get_arg
>>> ())))
>>> +         if (TREE_CODE (initvalop->get_type ()) == ENUMERAL_TYPE)
>>> +           {
>>> +             index_sval = initvalop;
>>> +             check_index_type = false;
>>> +           }
>>> +    }
>>>     /* If we're switching based on an enum type, assume that the user
>>> is only
>>>        working with values from the enum.  Hence if this is an
>>> @@ -5437,12 +5454,14 @@ apply_constraints_for_gswitch (const
>>> switch_cfg_superedge &edge,
>>>         ctxt
>>>         /* Must be an enum value.  */
>>>         && index_sval->get_type ()
>>> -      && TREE_CODE (TREE_TYPE (index)) == ENUMERAL_TYPE
>>> +      && (!check_index_type
>>> +         || TREE_CODE (TREE_TYPE (index)) == ENUMERAL_TYPE)
>>>         && TREE_CODE (index_sval->get_type ()) == ENUMERAL_TYPE
>>>         /* If we have a constant, then we can check it directly.  */
>>>         && index_sval->get_kind () != SK_CONSTANT
>>>         && edge.implicitly_created_default_p ()
>>> -      && has_nondefault_cases_for_all_enum_values_p (switch_stmt)
>>> +      && has_nondefault_cases_for_all_enum_values_p (switch_stmt,
>>> +                                                    index_sval-
>>>> get_type ())
>>>         /* Don't do this if there's a chance that the index is
>>>           attacker-controlled.  */
>>>         && !ctxt->possibly_tainted_p (index_sval))
>>> diff --git a/gcc/testsuite/gcc.dg/analyzer/switch-no-short-enum-1.c
>>> b/gcc/testsuite/gcc.dg/analyzer/switch-no-short-enum-1.c
>>> new file mode 100644
>>> index 0000000000000..98f6d91f97481
>>> --- /dev/null
>>> +++ b/gcc/testsuite/gcc.dg/analyzer/switch-no-short-enum-1.c
>>> @@ -0,0 +1,141 @@
>>> +/* { dg-do compile } */
>>> +/* { dg-additional-options "-fno-short-enums" } */
>>> +/* { dg-skip-if "default" { ! short_enums } } */
>>> +
>>> +#include "analyzer-decls.h"
>>> +
>>> +/* Verify the handling of "switch (enum_value)".  */
>>> +
>>> +enum e
>>> +{
>>> + E_VAL0,
>>> + E_VAL1,
>>> + E_VAL2
>>> +};
>>> +
>>> +/* Verify that we assume that "switch (enum)" doesn't follow
>>> implicit
>>> +   "default" if all enum values have cases  */
>>> +
>>> +int test_all_values_covered_implicit_default_1 (enum e x)
>>> +{
>>> +  switch (x)
>>> +    {
>>> +    case E_VAL0:
>>> +      return 1066;
>>> +    case E_VAL1:
>>> +      return 1776;
>>> +    case E_VAL2:
>>> +      return 1945;
>>> +    }
>>> +  __analyzer_dump_path (); /* { dg-bogus "path" } */
>>> +}
>>> +
>>> +int test_all_values_covered_implicit_default_2 (enum e x)
>>> +{
>>> +  int result;
>>> +  switch (x)
>>> +    {
>>> +    case E_VAL0:
>>> +      result = 1066;
>>> +      break;
>>> +    case E_VAL1:
>>> +      result = 1776;
>>> +      break;
>>> +    case E_VAL2:
>>> +      result = 1945;
>>> +      break;
>>> +    }
>>> +  return result; /* { dg-bogus "uninitialized" } */
>>> +}
>>> +
>>> +/* Verify that we consider paths that use the implicit default when
>>> not
>>> +   all enum values are covered by cases.  */
>>> +
>>> +int test_missing_values_implicit_default_1 (enum e x)
>>> +{
>>> +  switch (x) /* { dg-message "following 'default:' branch" } */
>>> +    {
>>> +    case E_VAL0:
>>> +      return 1066;
>>> +    case E_VAL1:
>>> +      return 1776;
>>> +    }
>>> +  __analyzer_dump_path (); /* { dg-message "path" } */
>>> +  return 0;
>>> +}
>>> +
>>> +int test_missing_values_implicit_default_2 (enum e x)
>>> +{
>>> +  int result;
>>> +  switch (x) /* { dg-message "following 'default:' branch" } */
>>> +    {
>>> +    case E_VAL0:
>>> +      result = 1066;
>>> +      break;
>>> +    case E_VAL1:
>>> +      result = 1776;
>>> +      break;
>>> +    }
>>> +  return result; /* { dg-warning "uninitialized" } */
>>> +}
>>> +
>>> +/* Verify that explicit "default" isn't rejected.  */
>>> +
>>> +int test_all_values_covered_explicit_default_1 (enum e x)
>>> +{
>>> +  switch (x)
>>> +    {
>>> +    case E_VAL0:
>>> +      return 1066;
>>> +    case E_VAL1:
>>> +      return 1776;
>>> +    case E_VAL2:
>>> +      return 1945;
>>> +    default:
>>> +      __analyzer_dump_path (); /* { dg-message "path" } */
>>> +      return 0;
>>> +    }
>>> +}
>>> +
>>> +int test_missing_values_explicit_default_1 (enum e x)
>>> +{
>>> +  switch (x)
>>> +    {
>>> +    default:
>>> +    case E_VAL0:
>>> +      return 1066;
>>> +    case E_VAL1:
>>> +      return 1776;
>>> +    }
>>> +  __analyzer_dump_path (); /* { dg-bogus "path" } */
>>> +  return 0;
>>> +}
>>> +
>>> +int test_missing_values_explicit_default_2 (enum e x)
>>> +{
>>> +  switch (x)
>>> +    {
>>> +    case E_VAL0:
>>> +      return 1066;
>>> +    case E_VAL1:
>>> +      return 1776;
>>> +    default:
>>> +      __analyzer_dump_path (); /* { dg-message "path" } */
>>> +      return 1945;
>>> +    }
>>> +  __analyzer_dump_path (); /* { dg-bogus "path" } */
>>> +  return 0;
>>> +}
>>> +
>>> +int test_just_default (enum e x)
>>> +{
>>> +  switch (x)
>>> +    {
>>> +    default:
>>> +      __analyzer_dump_path (); /* { dg-message "path" } */
>>> +      return 42;
>>> +    }
>>> +  __analyzer_dump_path (); /* { dg-bogus "path" } */
>>> +  return 0;
>>> +}
>>> +
>>> diff --git a/gcc/testsuite/gcc.dg/analyzer/switch-short-enum-1.c
>>> b/gcc/testsuite/gcc.dg/analyzer/switch-short-enum-1.c
>>> new file mode 100644
>>> index 0000000000000..384113fde5cbf
>>> --- /dev/null
>>> +++ b/gcc/testsuite/gcc.dg/analyzer/switch-short-enum-1.c
>>> @@ -0,0 +1,140 @@
>>> +/* { dg-do compile } */
>>> +/* { dg-additional-options "-fshort-enums" } */
>>> +/* { dg-skip-if "default" { short_enums } } */
>>> +
>>> +#include "analyzer-decls.h"
>>> +
>>> +/* Verify the handling of "switch (enum_value)".  */
>>> +
>>> +enum e
>>> +{
>>> + E_VAL0,
>>> + E_VAL1,
>>> + E_VAL2
>>> +};
>>> +
>>> +/* Verify that we assume that "switch (enum)" doesn't follow
>>> implicit
>>> +   "default" if all enum values have cases  */
>>> +
>>> +int test_all_values_covered_implicit_default_1 (enum e x)
>>> +{
>>> +  switch (x)
>>> +    {
>>> +    case E_VAL0:
>>> +      return 1066;
>>> +    case E_VAL1:
>>> +      return 1776;
>>> +    case E_VAL2:
>>> +      return 1945;
>>> +    }
>>> +  __analyzer_dump_path (); /* { dg-bogus "path" } */
>>> +}
>>> +
>>> +int test_all_values_covered_implicit_default_2 (enum e x)
>>> +{
>>> +  int result;
>>> +  switch (x)
>>> +    {
>>> +    case E_VAL0:
>>> +      result = 1066;
>>> +      break;
>>> +    case E_VAL1:
>>> +      result = 1776;
>>> +      break;
>>> +    case E_VAL2:
>>> +      result = 1945;
>>> +      break;
>>> +    }
>>> +  return result; /* { dg-bogus "uninitialized" } */
>>> +}
>>> +
>>> +/* Verify that we consider paths that use the implicit default when
>>> not
>>> +   all enum values are covered by cases.  */
>>> +
>>> +int test_missing_values_implicit_default_1 (enum e x)
>>> +{
>>> +  switch (x) /* { dg-message "following 'default:' branch" } */
>>> +    {
>>> +    case E_VAL0:
>>> +      return 1066;
>>> +    case E_VAL1:
>>> +      return 1776;
>>> +    }
>>> +  __analyzer_dump_path (); /* { dg-message "path" } */
>>> +  return 0;
>>> +}
>>> +
>>> +int test_missing_values_implicit_default_2 (enum e x)
>>> +{
>>> +  int result;
>>> +  switch (x) /* { dg-message "following 'default:' branch" } */
>>> +    {
>>> +    case E_VAL0:
>>> +      result = 1066;
>>> +      break;
>>> +    case E_VAL1:
>>> +      result = 1776;
>>> +      break;
>>> +    }
>>> +  return result; /* { dg-warning "uninitialized" } */
>>> +}
>>> +
>>> +/* Verify that explicit "default" isn't rejected.  */
>>> +
>>> +int test_all_values_covered_explicit_default_1 (enum e x)
>>> +{
>>> +  switch (x)
>>> +    {
>>> +    case E_VAL0:
>>> +      return 1066;
>>> +    case E_VAL1:
>>> +      return 1776;
>>> +    case E_VAL2:
>>> +      return 1945;
>>> +    default:
>>> +      __analyzer_dump_path (); /* { dg-message "path" } */
>>> +      return 0;
>>> +    }
>>> +}
>>> +
>>> +int test_missing_values_explicit_default_1 (enum e x)
>>> +{
>>> +  switch (x)
>>> +    {
>>> +    default:
>>> +    case E_VAL0:
>>> +      return 1066;
>>> +    case E_VAL1:
>>> +      return 1776;
>>> +    }
>>> +  __analyzer_dump_path (); /* { dg-bogus "path" } */
>>> +  return 0;
>>> +}
>>> +
>>> +int test_missing_values_explicit_default_2 (enum e x)
>>> +{
>>> +  switch (x)
>>> +    {
>>> +    case E_VAL0:
>>> +      return 1066;
>>> +    case E_VAL1:
>>> +      return 1776;
>>> +    default:
>>> +      __analyzer_dump_path (); /* { dg-message "path" } */
>>> +      return 1945;
>>> +    }
>>> +  __analyzer_dump_path (); /* { dg-bogus "path" } */
>>> +  return 0;
>>> +}
>>> +
>>> +int test_just_default (enum e x)
>>> +{
>>> +  switch (x)
>>> +    {
>>> +    default:
>>> +      __analyzer_dump_path (); /* { dg-message "path" } */
>>> +      return 42;
>>> +    }
>>> +  __analyzer_dump_path (); /* { dg-bogus "path" } */
>>> +  return 0;
>>> +}
>>>
>>>
>>