On Mon, Sep 14, 2015 at 5:28 PM, Richard Smith via cfe-commits <
cfe-commits@lists.llvm.org> wrote:
> On Mon, Sep 14, 2015 at 5:18 PM, Nico Weber via cfe-commits <
> cfe-commits@lists.llvm.org> wrote:
>
>> This also fires for bool in C++ files, even though the commit message
>> saying C11 and _Bool. Given the test changes, I suppose that's intentional?
>> This fires a lot on existing code, for example protobuf:
>>
>> ../../third_party/protobuf/src/google/protobuf/extension_set.h:465:10:
>> error: width of bit-field 'is_cleared' (4 bits) exceeds the width of its
>> type; value will be truncated to 1 bit [-Werror,-Wbitfield-width]
>> bool is_cleared : 4;
>> ^
>> ../../third_party/protobuf/src/google/protobuf/extension_set.h:472:10:
>> error: width of bit-field 'is_lazy' (4 bits) exceeds the width of its type;
>> value will be truncated to 1 bit [-Werror,-Wbitfield-width]
>> bool is_lazy : 4;
>> ^
>>
>> Is this expected? Is this a behavior change, or did the truncation happen
>> previously and it's now just getting warned on?
>>
>
> The code previously assumed that MSVC used the C rules here; it appears
> that's not true in all cases.
>
> Can we just remove the " || IsMsStruct ||
> Context.getTargetInfo().getCXXABI().isMicrosoft()"?
> Is there some reason we need to prohibit overwide bitfields for MS bitfield
> layout, rather than just warning on them? (Does record layout fail somehow?)
>
Record layout will fail for stuff like 'int x : 33' but will not fail for
stuff like '{bool,_Bool} y : 2'; the bitfield layout algorithm cares about
the storage size (which, of course, includes padding). This patch makes
'bool y : 2' an error which is a behavior change, I'm working on patch to
address this.
>
> On Mon, Sep 14, 2015 at 2:27 PM, Rachel Craik via cfe-commits <
>> cfe-commits@lists.llvm.org> wrote:
>>
>>> Author: rcraik
>>> Date: Mon Sep 14 16:27:36 2015
>>> New Revision: 247618
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=247618&view=rev
>>> Log:
>>> C11 _Bool bitfield diagnostic
>>>
>>> Summary: Implement DR262 (for C). This patch will mainly affect
>>> bitfields of type _Bool
>>>
>>> Reviewers: fraggamuffin, rsmith
>>>
>>> Subscribers: hubert.reinterpretcast, cfe-commits
>>>
>>> Differential Revision: http://reviews.llvm.org/D10018
>>>
>>> Modified:
>>> cfe/trunk/include/clang/Basic/DiagnosticGroups.td
>>> cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>>> cfe/trunk/lib/Sema/SemaDecl.cpp
>>> cfe/trunk/test/CodeGen/bitfield-2.c
>>> cfe/trunk/test/CodeGenCXX/warn-padded-packed.cpp
>>> cfe/trunk/test/Misc/warning-flags.c
>>> cfe/trunk/test/Sema/bitfield.c
>>> cfe/trunk/test/SemaCXX/bitfield-layout.cpp
>>> cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp
>>> cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp
>>> cfe/trunk/test/SemaCXX/ms_wide_bitfield.cpp
>>> cfe/trunk/test/SemaObjC/class-bitfield.m
>>>
>>> Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=247618&r1=247617&r2=247618&view=diff
>>>
>>> ==============================================================================
>>> --- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original)
>>> +++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Mon Sep 14
>>> 16:27:36 2015
>>> @@ -32,6 +32,7 @@ def AutoImport : DiagGroup<"auto-import"
>>> def GNUBinaryLiteral : DiagGroup<"gnu-binary-literal">;
>>> def GNUCompoundLiteralInitializer :
>>> DiagGroup<"gnu-compound-literal-initializer">;
>>> def BitFieldConstantConversion :
>>> DiagGroup<"bitfield-constant-conversion">;
>>> +def BitFieldWidth : DiagGroup<"bitfield-width">;
>>> def ConstantConversion :
>>> DiagGroup<"constant-conversion", [ BitFieldConstantConversion ] >;
>>> def LiteralConversion : DiagGroup<"literal-conversion">;
>>>
>>> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=247618&r1=247617&r2=247618&view=diff
>>>
>>> ==============================================================================
>>> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
>>> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Mon Sep 14
>>> 16:27:36 2015
>>> @@ -4314,20 +4314,21 @@ def err_bitfield_has_negative_width : Er
>>> def err_anon_bitfield_has_negative_width : Error<
>>> "anonymous bit-field has negative width (%0)">;
>>> def err_bitfield_has_zero_width : Error<"named bit-field %0 has zero
>>> width">;
>>> -def err_bitfield_width_exceeds_type_size : Error<
>>> - "size of bit-field %0 (%1 bits) exceeds size of its type (%2 bits)">;
>>> -def err_anon_bitfield_width_exceeds_type_size : Error<
>>> - "size of anonymous bit-field (%0 bits) exceeds size of its type (%1
>>> bits)">;
>>> +def err_bitfield_width_exceeds_type_width : Error<
>>> + "width of bit-field %0 (%1 bits) exceeds width of its type (%2
>>> bit%s2)">;
>>> +def err_anon_bitfield_width_exceeds_type_width : Error<
>>> + "width of anonymous bit-field (%0 bits) exceeds width of its type "
>>> + "(%1 bit%s1)">;
>>> def err_incorrect_number_of_vector_initializers : Error<
>>> "number of elements must be either one or match the size of the
>>> vector">;
>>>
>>> // Used by C++ which allows bit-fields that are wider than the type.
>>> -def warn_bitfield_width_exceeds_type_size: Warning<
>>> - "size of bit-field %0 (%1 bits) exceeds the size of its type; value
>>> will be "
>>> - "truncated to %2 bits">;
>>> -def warn_anon_bitfield_width_exceeds_type_size : Warning<
>>> - "size of anonymous bit-field (%0 bits) exceeds size of its type;
>>> value will "
>>> - "be truncated to %1 bits">;
>>> +def warn_bitfield_width_exceeds_type_width: Warning<
>>> + "width of bit-field %0 (%1 bits) exceeds the width of its type; value
>>> will "
>>> + "be truncated to %2 bit%s2">, InGroup<BitFieldWidth>;
>>> +def warn_anon_bitfield_width_exceeds_type_width : Warning<
>>> + "width of anonymous bit-field (%0 bits) exceeds width of its type;
>>> value "
>>> + "will be truncated to %1 bit%s1">, InGroup<BitFieldWidth>;
>>>
>>> def warn_missing_braces : Warning<
>>> "suggest braces around initialization of subobject">,
>>>
>>> Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=247618&r1=247617&r2=247618&view=diff
>>>
>>> ==============================================================================
>>> --- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
>>> +++ cfe/trunk/lib/Sema/SemaDecl.cpp Mon Sep 14 16:27:36 2015
>>> @@ -12625,26 +12625,26 @@ ExprResult Sema::VerifyBitField(SourceLo
>>> }
>>>
>>> if (!FieldTy->isDependentType()) {
>>> - uint64_t TypeSize = Context.getTypeSize(FieldTy);
>>> - if (Value.getZExtValue() > TypeSize) {
>>> + uint64_t TypeWidth = Context.getIntWidth(FieldTy);
>>> + if (Value.ugt(TypeWidth)) {
>>> if (!getLangOpts().CPlusPlus || IsMsStruct ||
>>> Context.getTargetInfo().getCXXABI().isMicrosoft()) {
>>> if (FieldName)
>>> - return Diag(FieldLoc,
>>> diag::err_bitfield_width_exceeds_type_size)
>>> + return Diag(FieldLoc,
>>> diag::err_bitfield_width_exceeds_type_width)
>>> << FieldName << (unsigned)Value.getZExtValue()
>>> - << (unsigned)TypeSize;
>>> + << (unsigned)TypeWidth;
>>>
>>> - return Diag(FieldLoc,
>>> diag::err_anon_bitfield_width_exceeds_type_size)
>>> - << (unsigned)Value.getZExtValue() << (unsigned)TypeSize;
>>> + return Diag(FieldLoc,
>>> diag::err_anon_bitfield_width_exceeds_type_width)
>>> + << (unsigned)Value.getZExtValue() << (unsigned)TypeWidth;
>>> }
>>>
>>> if (FieldName)
>>> - Diag(FieldLoc, diag::warn_bitfield_width_exceeds_type_size)
>>> + Diag(FieldLoc, diag::warn_bitfield_width_exceeds_type_width)
>>> << FieldName << (unsigned)Value.getZExtValue()
>>> - << (unsigned)TypeSize;
>>> + << (unsigned)TypeWidth;
>>> else
>>> - Diag(FieldLoc, diag::warn_anon_bitfield_width_exceeds_type_size)
>>> - << (unsigned)Value.getZExtValue() << (unsigned)TypeSize;
>>> + Diag(FieldLoc,
>>> diag::warn_anon_bitfield_width_exceeds_type_width)
>>> + << (unsigned)Value.getZExtValue() << (unsigned)TypeWidth;
>>> }
>>> }
>>>
>>>
>>> Modified: cfe/trunk/test/CodeGen/bitfield-2.c
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/bitfield-2.c?rev=247618&r1=247617&r2=247618&view=diff
>>>
>>> ==============================================================================
>>> --- cfe/trunk/test/CodeGen/bitfield-2.c (original)
>>> +++ cfe/trunk/test/CodeGen/bitfield-2.c Mon Sep 14 16:27:36 2015
>>> @@ -237,7 +237,7 @@ unsigned long long test_5() {
>>> /***/
>>>
>>> struct s6 {
>>> - _Bool f0 : 2;
>>> + unsigned f0 : 2;
>>> };
>>>
>>> struct s6 g6 = { 0xF };
>>>
>>> Modified: cfe/trunk/test/CodeGenCXX/warn-padded-packed.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/warn-padded-packed.cpp?rev=247618&r1=247617&r2=247618&view=diff
>>>
>>> ==============================================================================
>>> --- cfe/trunk/test/CodeGenCXX/warn-padded-packed.cpp (original)
>>> +++ cfe/trunk/test/CodeGenCXX/warn-padded-packed.cpp Mon Sep 14 16:27:36
>>> 2015
>>> @@ -69,7 +69,7 @@ struct S12 {
>>>
>>> struct S13 { // expected-warning {{padding size of 'S13' with 6 bits to
>>> alignment boundary}}
>>> char c;
>>> - bool b : 10; // expected-warning {{size of bit-field 'b' (10 bits)
>>> exceeds the size of its type}}
>>> + bool b : 10; // expected-warning {{width of bit-field 'b' (10 bits)
>>> exceeds the width of its type}}
>>> };
>>>
>>> // The warnings are emitted when the layout of the structs is computed,
>>> so we have to use them.
>>>
>>> Modified: cfe/trunk/test/Misc/warning-flags.c
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Misc/warning-flags.c?rev=247618&r1=247617&r2=247618&view=diff
>>>
>>> ==============================================================================
>>> --- cfe/trunk/test/Misc/warning-flags.c (original)
>>> +++ cfe/trunk/test/Misc/warning-flags.c Mon Sep 14 16:27:36 2015
>>> @@ -18,7 +18,7 @@ This test serves two purposes:
>>>
>>> The list of warnings below should NEVER grow. It should gradually
>>> shrink to 0.
>>>
>>> -CHECK: Warnings without flags (92):
>>> +CHECK: Warnings without flags (90):
>>> CHECK-NEXT: ext_excess_initializers
>>> CHECK-NEXT: ext_excess_initializers_in_char_array_initializer
>>> CHECK-NEXT: ext_expected_semi_decl_list
>>> @@ -44,10 +44,8 @@ CHECK-NEXT: pp_pragma_once_in_main_fil
>>> CHECK-NEXT: pp_pragma_sysheader_in_main_file
>>> CHECK-NEXT: w_asm_qualifier_ignored
>>> CHECK-NEXT: warn_accessor_property_type_mismatch
>>> -CHECK-NEXT: warn_anon_bitfield_width_exceeds_type_size
>>> CHECK-NEXT: warn_arcmt_nsalloc_realloc
>>> CHECK-NEXT: warn_asm_label_on_auto_decl
>>> -CHECK-NEXT: warn_bitfield_width_exceeds_type_size
>>> CHECK-NEXT: warn_c_kext
>>> CHECK-NEXT: warn_call_to_pure_virtual_member_function_from_ctor_dtor
>>> CHECK-NEXT: warn_call_wrong_number_of_arguments
>>>
>>> Modified: cfe/trunk/test/Sema/bitfield.c
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/bitfield.c?rev=247618&r1=247617&r2=247618&view=diff
>>>
>>> ==============================================================================
>>> --- cfe/trunk/test/Sema/bitfield.c (original)
>>> +++ cfe/trunk/test/Sema/bitfield.c Mon Sep 14 16:27:36 2015
>>> @@ -6,7 +6,7 @@ struct a {
>>> int a : -1; // expected-error{{bit-field 'a' has negative width}}
>>>
>>> // rdar://6081627
>>> - int b : 33; // expected-error{{size of bit-field 'b' (33 bits)
>>> exceeds size of its type (32 bits)}}
>>> + int b : 33; // expected-error{{width of bit-field 'b' (33 bits)
>>> exceeds width of its type (32 bits)}}
>>>
>>> int c : (1 + 0.25); // expected-error{{expression is not an integer
>>> constant expression}}
>>> int d : (int)(1 + 0.25);
>>> @@ -22,9 +22,12 @@ struct a {
>>> int g : (_Bool)1;
>>>
>>> // PR4017
>>> - char : 10; // expected-error {{size of anonymous bit-field (10
>>> bits) exceeds size of its type (8 bits)}}
>>> + char : 10; // expected-error {{width of anonymous bit-field (10
>>> bits) exceeds width of its type (8 bits)}}
>>> unsigned : -2; // expected-error {{anonymous bit-field has negative
>>> width (-2)}}
>>> float : 12; // expected-error {{anonymous bit-field has
>>> non-integral type 'float'}}
>>> +
>>> + _Bool : 2; // expected-error {{width of anonymous bit-field (2
>>> bits) exceeds width of its type (1 bit)}}
>>> + _Bool h : 5; // expected-error {{width of bit-field 'h' (5 bits)
>>> exceeds width of its type (1 bit)}}
>>> };
>>>
>>> struct b {unsigned x : 2;} x;
>>>
>>> Modified: cfe/trunk/test/SemaCXX/bitfield-layout.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/bitfield-layout.cpp?rev=247618&r1=247617&r2=247618&view=diff
>>>
>>> ==============================================================================
>>> --- cfe/trunk/test/SemaCXX/bitfield-layout.cpp (original)
>>> +++ cfe/trunk/test/SemaCXX/bitfield-layout.cpp Mon Sep 14 16:27:36 2015
>>> @@ -5,25 +5,25 @@
>>>
>>> // Simple tests.
>>> struct Test1 {
>>> - char c : 9; // expected-warning {{size of bit-field 'c' (9 bits)
>>> exceeds the size of its type; value will be truncated to 8 bits}}
>>> + char c : 9; // expected-warning {{width of bit-field 'c' (9 bits)
>>> exceeds the width of its type; value will be truncated to 8 bits}}
>>> };
>>> CHECK_SIZE(Test1, 2);
>>> CHECK_ALIGN(Test1, 1);
>>>
>>> struct Test2 {
>>> - char c : 16; // expected-warning {{size of bit-field 'c' (16 bits)
>>> exceeds the size of its type; value will be truncated to 8 bits}}
>>> + char c : 16; // expected-warning {{width of bit-field 'c' (16 bits)
>>> exceeds the width of its type; value will be truncated to 8 bits}}
>>> };
>>> CHECK_SIZE(Test2, 2);
>>> CHECK_ALIGN(Test2, 2);
>>>
>>> struct Test3 {
>>> - char c : 32; // expected-warning {{size of bit-field 'c' (32 bits)
>>> exceeds the size of its type; value will be truncated to 8 bits}}
>>> + char c : 32; // expected-warning {{width of bit-field 'c' (32 bits)
>>> exceeds the width of its type; value will be truncated to 8 bits}}
>>> };
>>> CHECK_SIZE(Test3, 4);
>>> CHECK_ALIGN(Test3, 4);
>>>
>>> struct Test4 {
>>> - char c : 64; // expected-warning {{size of bit-field 'c' (64 bits)
>>> exceeds the size of its type; value will be truncated to 8 bits}}
>>> + char c : 64; // expected-warning {{width of bit-field 'c' (64 bits)
>>> exceeds the width of its type; value will be truncated to 8 bits}}
>>> };
>>> CHECK_SIZE(Test4, 8);
>>> CHECK_ALIGN(Test4, 8);
>>>
>>> Modified: cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp?rev=247618&r1=247617&r2=247618&view=diff
>>>
>>> ==============================================================================
>>> --- cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp (original)
>>> +++ cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp Mon Sep 14
>>> 16:27:36 2015
>>> @@ -1801,9 +1801,9 @@ namespace Bitfields {
>>> bool b : 1;
>>> unsigned u : 5;
>>> int n : 5;
>>> - bool b2 : 3;
>>> - unsigned u2 : 74; // expected-warning {{exceeds the size of its
>>> type}}
>>> - int n2 : 81; // expected-warning {{exceeds the size of its type}}
>>> + bool b2 : 3; // expected-warning {{exceeds the width of its type}}
>>> + unsigned u2 : 74; // expected-warning {{exceeds the width of its
>>> type}}
>>> + int n2 : 81; // expected-warning {{exceeds the width of its type}}
>>> };
>>>
>>> constexpr A a = { false, 33, 31, false, 0xffffffff, 0x7fffffff }; //
>>> expected-warning 2{{truncation}}
>>>
>>> Modified: cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp?rev=247618&r1=247617&r2=247618&view=diff
>>>
>>> ==============================================================================
>>> --- cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp (original)
>>> +++ cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp Mon Sep 14
>>> 16:27:36 2015
>>> @@ -872,7 +872,7 @@ namespace Lifetime {
>>>
>>> namespace Bitfields {
>>> struct A {
>>> - bool b : 3;
>>> + bool b : 1;
>>> int n : 4;
>>> unsigned u : 5;
>>> };
>>>
>>> Modified: cfe/trunk/test/SemaCXX/ms_wide_bitfield.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/ms_wide_bitfield.cpp?rev=247618&r1=247617&r2=247618&view=diff
>>>
>>> ==============================================================================
>>> --- cfe/trunk/test/SemaCXX/ms_wide_bitfield.cpp (original)
>>> +++ cfe/trunk/test/SemaCXX/ms_wide_bitfield.cpp Mon Sep 14 16:27:36 2015
>>> @@ -1,9 +1,10 @@
>>> // RUN: %clang_cc1 -fno-rtti -emit-llvm-only -triple i686-pc-win32
>>> -fdump-record-layouts -fsyntax-only -mms-bitfields -verify %s 2>&1
>>>
>>> struct A {
>>> - char a : 9; // expected-error{{size of bit-field 'a' (9 bits) exceeds
>>> size of its type (8 bits)}}
>>> - int b : 33; // expected-error{{size of bit-field 'b' (33 bits)
>>> exceeds size of its type (32 bits)}}
>>> - bool c : 9; // expected-error{{size of bit-field 'c' (9 bits) exceeds
>>> size of its type (8 bits)}}
>>> + char a : 9; // expected-error{{width of bit-field 'a' (9 bits)
>>> exceeds width of its type (8 bits)}}
>>> + int b : 33; // expected-error{{width of bit-field 'b' (33 bits)
>>> exceeds width of its type (32 bits)}}
>>> + bool c : 9; // expected-error{{width of bit-field 'c' (9 bits)
>>> exceeds width of its type (1 bit)}}
>>> + bool d : 3; // expected-error{{width of bit-field 'd' (3 bits)
>>> exceeds width of its type (1 bit)}}
>>> };
>>>
>>> int a[sizeof(A) == 1 ? 1 : -1];
>>>
>>> Modified: cfe/trunk/test/SemaObjC/class-bitfield.m
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/class-bitfield.m?rev=247618&r1=247617&r2=247618&view=diff
>>>
>>> ==============================================================================
>>> --- cfe/trunk/test/SemaObjC/class-bitfield.m (original)
>>> +++ cfe/trunk/test/SemaObjC/class-bitfield.m Mon Sep 14 16:27:36 2015
>>> @@ -5,7 +5,7 @@
>>> int a : -1; // expected-error{{bit-field 'a' has negative width}}
>>>
>>> // rdar://6081627
>>> - int b : 33; // expected-error{{size of bit-field 'b' (33 bits)
>>> exceeds size of its type (32 bits)}}
>>> + int b : 33; // expected-error{{width of bit-field 'b' (33 bits)
>>> exceeds width of its type (32 bits)}}
>>>
>>> int c : (1 + 0.25); // expected-error{{expression is not an integer
>>> constant expression}}
>>> int d : (int)(1 + 0.25);
>>>
>>>
>>> _______________________________________________
>>> cfe-commits mailing list
>>> cfe-commits@lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
>>>
>>
>>
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