Bug 315215 – REGRESSION(310262@main): [lldb] dump_class_layout_unittest.serial_test_InheritsFromClassWithPaddedBitfields fails constantly across all platforms.

• Status: NEW
• Component: New Bugs

[Diego De La Toba]

Summary:
dump_class_layout_unittest.TestDumpClassLayout.serial_test_InheritsFromClassWithPaddedBitfields
(Tools/lldb/dump_class_layout_unittest.py:373) has been failing continuously on post-commit since
310262@main.

LOG/Trace:
https://build.webkit.org/#/builders/1716/builds/4051/steps/26/logs/stdio

DIFF:
 Expected: Total byte size: 24  Total pad bytes: 14  Padding 61.98 %   derivedBitfield @ +16
 Actual:   Total byte size: 16  Total pad bytes:  6  Padding 42.97 %   derivedBitfield @ +10

TRACE:
[9/48] dump_class_layout_unittest.TestDumpClassLayout.serial_test_InheritsFromClassWithPaddedBitfields failed:
Traceback (most recent call last):'
File
"Volumes/Data/worker/Apple-Tahoe-Release-AppleSilicon-WK2-Tests/build/Tools/11db/dump_class_layout_unittest.py", line 397, in serial_test_InheritsFromClassWithPadd
self. assertEqual(EXPECTED_RESULT, actual_layout.as_string())
AssertionError:
+0 < 24> InheritsFromClassWithPaddedBitfields\[834 chars]98%' != ' +0 < 16› InheritsFromClassWithPaddedBitfields\[798 chars]97 %'
+0 < 24> InheritsFromClassWithPaddedBitfields
+0 <
16>
InheritsFromClassWithPaddedBitfields
?
+0
+0
+1
+1
+1
+1
+1
+1
+2
+4
+8
+8
+9
+9
+10
+16
< 16>
1>
: 1>
: 1>
: 2>
:1>
:2>
:1>
1>
4>
: 1>
:9>
: 1>
: 5>
6>
:1>
ClassWithPaddedBitfields ClassWithPaddedBitfields
bool boolMember
unsigned int bitfieldl : 1
bool bitfield2: 1
unsigned int bitfield3 : 2
unsigned int bitfield4 : 1
unsigned long bitfield5 : 2
<UNUSED BITS: 1 bit›
«PADDING: 1 bytes›
int intMember
unsigned int bitfield?: 1
unsigned int bitfield8: 9
bool bitfield9: 1
<UNUSED BITS: 5 bits›
<PADDING: 6 bytes>
bool derivedBitfield: 1
+10 < : 1>
bool derivedBitfield: 1
?
?
+16
1
:7>
+10
<:7>
<UNUSED BITS: 7 bits›
<UNUSED BITS: 7 bits›
?
?
17+
1
> 11+
7>
<PADDING: 7 bytes>
5>
<PADDING: 5 bytes>
?
- Total byte size: 24
?
→ Total byte size: 16
- Total pad bytes: 14
?
+ Total pad bytes: 6
?
- Padding percentage: 61.98 %?
+ Padding percentage: 42.97 %?

[Radar WebKit Bug Importer]

<rdar://problem/177546068>

[David Kilzer (:ddkilzer)]

Pull request: https://github.com/WebKit/WebKit/pull/65641