8 Commits

Author SHA1 Message Date
Raphael Isemann
e2ede1715d [lldb] Update field offset/sizes when encountering artificial members such as vtable pointers
`DWARFASTParserClang::ParseSingleMember` turns DWARF DIEs that describe
struct/class members into their respective Clang representation (e.g.,
clang::FieldDecl). It also updates a record of where the last field
started/ended so that we can speculatively fill any holes between a field and a
bitfield with unnamed bitfield padding.

Right now we are completely ignoring 'artificial' members when parsing the DWARF
of a struct/class. The only artificial member that seems to be emitted in
practice for C/C++ seems to be the vtable pointer.

By completely skipping both the Clang AST node creation and the updating of the
last-field record, we essentially leave a hole in our layout with the size of
our artificial member. If the next member is a bitfield we then speculatively
fill the hole with an unnamed bitfield. During CodeGen Clang inserts an
artificial vtable pointer into the layout again which now occupies the same
offset as the unnamed bitfield. This later brings down Clang's
`CGRecordLowering::insertPadding` when it checks that none of the fields of the
generated record layout overlap.

Note that this is not a Clang bug. We explicitly set the offset of our fields in
LLDB and overwrite whatever Clang makes up.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D112697
2021-10-30 13:22:21 +02:00
Raphael Isemann
974c2f5e22 [lldb] Modernize and expand TestCppBitfields
* clang-format test source.
* Removed the dead setup code.
* Using expect_expr etc. instead of raw expect.
* Slightly expanded with tests for vtable pointers (which mostly just crash atm.)
* Removed some other minor test guideline problems.
2021-10-25 18:19:26 +02:00
David Blaikie
aee4925507 Recommit: Compress formatting of array type names (int [4] -> int[4])
Based on post-commit review discussion on
2bd84938470bf2e337801faafb8a67710f46429d with Richard Smith.

Other uses of forcing HasEmptyPlaceHolder to false seem OK to me -
they're all around pointer/reference types where the pointer/reference
token will appear at the rightmost side of the left side of the type
name, so they make nested types (eg: the "int" in "int *") behave as
though there is a non-empty placeholder (because the "*" is essentially
the placeholder as far as the "int" is concerned).

This was originally committed in 277623f4d5a672d707390e2c3eaf30a9eb4b075c

Reverted in f9ad1d1c775a8e264bebc15d75e0c6e5c20eefc7 due to breakages
outside of clang - lldb seems to have some strange/strong dependence on
"char [N]" versus "char[N]" when printing strings (not due to that name
appearing in DWARF, but probably due to using clang to stringify type
names) that'll need to be addressed, plus a few other odds and ends in
other subprojects (clang-tools-extra, compiler-rt, etc).
2021-10-21 11:34:43 -07:00
Andy Yankovsky
6c83d4a60b [lldb] Enable TestCppBitfields on Windows
The test works correctly on Windows, the linked bug has been resolved.

Reviewed By: teemperor

Differential Revision: https://reviews.llvm.org/D102769
2021-05-19 17:04:19 +02:00
Andy Yankovsky
0bab7b26f4 [lldb] Encode bool as unsigned int
`bool` is considered to be unsigned according to `std::is_unsigned<bool>::value` (and `Type::GetTypeInfo`). Encoding it as signed int works fine for normal variables and fields, but breaks when reading the values of boolean bitfields. If the field is declared as `bool b : 1` and has a value of `0b1`, the call to `SBValue::GetValueAsSigned()` will return `-1`.

Reviewed By: teemperor

Differential Revision: https://reviews.llvm.org/D102685
2021-05-19 15:32:17 +02:00
shafik
bae9aedb34 [LLDB] Fix handling of bit-fields in a union
When parsing DWARF and laying out bit-fields we don't properly take into account when they are in a union, they will all have a zero offset.

Differential Revision: https://reviews.llvm.org/D91118
2020-11-12 14:09:27 -08:00
shafik
00c8120acb [LLDB] Fix handling of bit-fields when there is a base class when parsing DWARF
When parsing DWARF and laying out bit-fields we currently don't take into account whether we have a base class or not.
Currently if the first field is a bit-field but the bit offset is due a field we inherit from a base class we currently
treat it as an unnamed bit-field and therefore add an extra field.

This fix will not check if we have a base class and assume that this offset is due to members we are inheriting from the base.
We are currently seeing asserts during codegen when debugging clang::DiagnosticOptions.

This assumption will fail in the case where the first field in the derived class in an unnamed bit-field. Fixing the first field
being an unnamed bit-field looks like it will require a larger change since we will need a way to track or discover the last field offset of the bases(s).

Differential Revision: https://reviews.llvm.org/D76808
2020-03-27 11:28:07 -07:00
Jordan Rupprecht
99451b4453 [lldb][test] Remove symlink for API tests.
Summary: Moves lldbsuite tests to lldb/test/API.

This is a largely mechanical change, moved with the following steps:

```
rm lldb/test/API/testcases
mkdir -p lldb/test/API/{test_runner/test,tools/lldb-{server,vscode}}
mv lldb/packages/Python/lldbsuite/test/test_runner/test lldb/test/API/test_runner
for d in $(find lldb/packages/Python/lldbsuite/test/* -maxdepth 0 -type d | egrep -v "make|plugins|test_runner|tools"); do mv $d lldb/test/API; done
for d in $(find lldb/packages/Python/lldbsuite/test/tools/lldb-vscode -maxdepth 1 -mindepth 1 | grep -v ".py"); do mv $d lldb/test/API/tools/lldb-vscode; done
for d in $(find lldb/packages/Python/lldbsuite/test/tools/lldb-server -maxdepth 1 -mindepth 1 | egrep -v "gdbremote_testcase.py|lldbgdbserverutils.py|socket_packet_pump.py"); do mv $d lldb/test/API/tools/lldb-server; done
```

lldb/packages/Python/lldbsuite/__init__.py and lldb/test/API/lit.cfg.py were also updated with the new directory structure.

Reviewers: labath, JDevlieghere

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71151
2020-02-11 10:03:53 -08:00