[Sema] expose a control flag for integer to pointer ext warning

[Kader]

Summary

While building openJDK11u, it seems that some of the code in the native core libraries make liberal use of integer to pointer comparisons. We currently have no flag to disabled this warning. This add such a flag.

(eg https://github.com/AdoptOpenJDK/openjdk-jdk11/blob/19fb8f93c59dfd791f62d41f332db9e306bc1422/src/java.desktop/unix/native/common/awt/awt_Font.c#L641)

[lebedev.ri]

Looks ok in general.
Perhaps there should be a test for this flag specifically?
Also, should "pointer-integer-compare" be in some group?

[Kader]

Added test case for C_lang

[Kader]

@lebedev.ri Thanks for the quick review ;

Perhaps there should be a test for this flag specifically?

I am not really familiar with this part of the code base, but it seems that the warnings is already tested in both test/Sema/Compare.c and test/SemaCXX/compare.cpp. I have none the less added a new test file for c_lang.

Also, should "pointer-integer-compare" be in some group?

I modeled my change on ext_typecheck_ordered_comparison_of_function_pointers which doesn't belong to any group. Not sure if that's the right thing to do though.

Also, this flag is only valid for C_lang and not for Cpp_lang. But right now the flag will be silently ignore when compiling cpp files. Is that an acceptable behavior ?

[Kader]

added missing test file

[lebedev.ri]

test/Sema/ext-typecheck-comparison-of-pointer-integer.c

1

I guess you want a run-line with no flag, this runline, and a run-line with -Wno-pointer-integer-compare

[Kader]

address comments

[Kader]

remove typo

[Kader]

test/Sema/ext-typecheck-comparison-of-pointer-integer.c

1

done

[lebedev.ri]

ok, LGTM.

test/Sema/ext-typecheck-comparison-of-pointer-integer.c

1

In the future, do use that checkbox on the inline comments to mark them as done.

[Kader]

@lebedev.ri Thanks.
I think do not have commit access. What should be my next step ?

[Kader]

friendly ping

[kristina]

Going to test and land it as requested by @lebedev.ri on IRC.

include/clang/Basic/DiagnosticSemaKinds.td

 def ext_typecheck_ordered_comparison_of_function_pointers : ExtWarn<
   "ordered comparison of function pointers (%0 and %1)">,
   InGroup<DiagGroup<"ordered-compare-function-pointers">>;
 def ext_typecheck_comparison_of_fptr_to_void : Extension<
   "equality comparison between function pointer and void pointer (%0 and %1)">;
 def err_typecheck_comparison_of_fptr_to_void : Error<
   "equality comparison between function pointer and void pointer (%0 and %1)">;
 def ext_typecheck_comparison_of_pointer_integer : ExtWarn<
-  "comparison between pointer and integer (%0 and %1)">;
+  "comparison between pointer and integer (%0 and %1)">,
+  InGroup<DiagGroup<"pointer-integer-compare">>;
 def err_typecheck_comparison_of_pointer_integer : Error<
   "comparison between pointer and integer (%0 and %1)">;
 def ext_typecheck_comparison_of_distinct_pointers : ExtWarn<
   "comparison of distinct pointer types%diff{ ($ and $)|}0,1">,
   InGroup<CompareDistinctPointerType>;
 def ext_typecheck_cond_incompatible_operands : ExtWarn<
   "incompatible operand types (%0 and %1)">;
 def err_cond_voidptr_arc : Error <

test/Misc/warning-flags.c

(2) It prevents us adding new warnings to Clang that have no -W flag.  All
     new warnings should have -W flags.
 
     If you add a new warning without a flag, this test will fail.  To fix
     this test, simply add a warning group to that warning.
 
 
 The list of warnings below should NEVER grow.  It should gradually shrink to 0.
 
-CHECK: Warnings without flags (75):
+CHECK: Warnings without flags (74):
 CHECK-NEXT:   ext_excess_initializers
 CHECK-NEXT:   ext_excess_initializers_in_char_array_initializer
 CHECK-NEXT:   ext_expected_semi_decl_list
 CHECK-NEXT:   ext_explicit_specialization_storage_class
 CHECK-NEXT:   ext_initializer_string_for_char_array_too_long
 CHECK-NEXT:   ext_missing_declspec
 CHECK-NEXT:   ext_missing_whitespace_after_macro_name
 CHECK-NEXT:   ext_new_paren_array_nonconst
 CHECK-NEXT:   ext_plain_complex
 CHECK-NEXT:   ext_template_arg_extra_parens
-CHECK-NEXT:   ext_typecheck_comparison_of_pointer_integer
 CHECK-NEXT:   ext_typecheck_cond_incompatible_operands
 CHECK-NEXT:   ext_typecheck_ordered_comparison_of_pointer_integer
 CHECK-NEXT:   ext_using_undefined_std
 CHECK-NEXT:   pp_invalid_string_literal
 CHECK-NEXT:   pp_out_of_date_dependency
 CHECK-NEXT:   pp_poisoning_existing_macro
 CHECK-NEXT:   warn_accessor_property_type_mismatch
 CHECK-NEXT:   warn_arcmt_nsalloc_realloc

test/Sema/ext-typecheck-comparison-of-pointer-integer.c

+// RUN: %clang_cc1 -triple x86_64-apple-darwin -fsyntax-only  -verify -Wpointer-integer-compare %s 
+
+int test_ext_typecheck_comparison_of_pointer_integer(int integer, int * pointer) {
+  return integer != pointer;  // expected-warning {{comparison between pointer and integer ('int' and 'int *')}}
+}