Commit Graph

374 Commits

Author SHA1 Message Date
Michael Buch
2bf01d73f6 [lldb][DWARFASTParserClang] GetClangDeclForDIE: don't create VarDecl for static data members (#77155)
With DWARFv5, C++ static data members are represented as
`DW_TAG_variable`s (see `faa3a5ea9ae481da757dab1c95c589e2d5645982`).

In GetClangDeclForDIE, when trying to parse the `DW_AT_specification`
that a static data member's CU-level `DW_TAG_variable` points to, we
would try to `CreateVariableDeclaration`. Whereas previously it was a
no-op (for `DW_TAG_member`s). However, adding `VarDecls` to RecordDecls
for static data members should always be done in
`CreateStaticMemberVariable`. The test-case is an exapmle where we would
crash if we tried to create a `VarDecl` from within `GetClangDeclForDIE`
for a static data member.

This patch simply checks whether the `DW_TAG_variable` being parsed is a
static data member, and if so, trivially returns from
`GetClangDeclForDIE` (as we previously did for `DW_TAG_member`s).
2024-01-08 14:10:02 +00:00
Greg Clayton
e42edb5547 [lldb] Fix expressions that involve nested structs/classes/unions. (#77029)
The LLDB expression parser relies on using the external AST source
support in LLDB. This allows us to find a class at the root namespace
level, but it wouldn't allow us to find nested classes all of the time.
When LLDB finds a class via this mechanism, it would be able to complete
this class when needed, but during completion, we wouldn't populate
nested types within this class which would prevent us from finding
contained types when needed as clang would expect them to be present if
a class was completed. When we parse a type for a class, struct or
union, we make a forward declaration to the class which can be
completed. Now when the class is completed, we also add any contained
types to the class' declaration context which now allows these types to
be found. If we have a struct that contains a struct, we will add the
forward declaration of the contained structure which can be c ompleted
later. Having this forward declaration makes it possible for LLDB to
find everything it needs now.

This should fix an existing issue:
https://github.com/llvm/llvm-project/issues/53904

Previously, contained types could be parsed by accident and allow
expression to complete successfully. Other times we would have to run an
expression multiple times because our old type lookup from our
expressions would cau se a type to be parsed, but not used in the
current expression, but this would have parsed a type into the
containing decl context and the expression might succeed if it is run
again.
2024-01-05 09:26:54 -08:00
David Spickett
7767c5856d [lldb][DWARF] Search for symbols in all external modules (#75927)
The way this code was updated in
dd95877958 meant that if the first module
did not have the symbol, the iteration stopped as returning true means
stop. So only if every module had the symbol would we find it, in the
last module.

Invert the condition to break when we find the first instance, which is
what the previous code did.
2023-12-20 14:48:01 +00:00
Greg Clayton
dd95877958 [lldb] Make only one function that needs to be implemented when searching for types (#74786)
This patch revives the effort to get this Phabricator patch into
upstream:

https://reviews.llvm.org/D137900

This patch was accepted before in Phabricator but I found some
-gsimple-template-names issues that are fixed in this patch.

A fixed up version of the description from the original patch starts
now.

This patch started off trying to fix Module::FindFirstType() as it
sometimes didn't work. The issue was the SymbolFile plug-ins didn't do
any filtering of the matching types they produced, and they only looked
up types using the type basename. This means if you have two types with
the same basename, your type lookup can fail when only looking up a
single type. We would ask the Module::FindFirstType to lookup "Foo::Bar"
and it would ask the symbol file to find only 1 type matching the
basename "Bar", and then we would filter out any matches that didn't
match "Foo::Bar". So if the SymbolFile found "Foo::Bar" first, then it
would work, but if it found "Baz::Bar" first, it would return only that
type and it would be filtered out.

Discovering this issue lead me to think of the patch Alex Langford did a
few months ago that was done for finding functions, where he allowed
SymbolFile objects to make sure something fully matched before parsing
the debug information into an AST type and other LLDB types. So this
patch aimed to allow type lookups to also be much more efficient.

As LLDB has been developed over the years, we added more ways to to type
lookups. These functions have lots of arguments. This patch aims to make
one API that needs to be implemented that serves all previous lookups:

- Find a single type
- Find all types
- Find types in a namespace

This patch introduces a `TypeQuery` class that contains all of the state
needed to perform the lookup which is powerful enough to perform all of
the type searches that used to be in our API. It contain a vector of
CompilerContext objects that can fully or partially specify the lookup
that needs to take place.

If you just want to lookup all types with a matching basename,
regardless of the containing context, you can specify just a single
CompilerContext entry that has a name and a CompilerContextKind mask of
CompilerContextKind::AnyType.

Or you can fully specify the exact context to use when doing lookups
like: CompilerContextKind::Namespace "std"
CompilerContextKind::Class "foo"
CompilerContextKind::Typedef "size_type"

This change expands on the clang modules code that already used a
vector<CompilerContext> items, but it modifies it to work with
expression type lookups which have contexts, or user lookups where users
query for types. The clang modules type lookup is still an option that
can be enabled on the `TypeQuery` objects.

This mirrors the most recent addition of type lookups that took a
vector<CompilerContext> that allowed lookups to happen for the
expression parser in certain places.

Prior to this we had the following APIs in Module:

```
void
Module::FindTypes(ConstString type_name, bool exact_match, size_t max_matches,
                  llvm::DenseSet<lldb_private::SymbolFile *> &searched_symbol_files,
                  TypeList &types);

void
Module::FindTypes(llvm::ArrayRef<CompilerContext> pattern, LanguageSet languages,
                  llvm::DenseSet<lldb_private::SymbolFile *> &searched_symbol_files,
                  TypeMap &types);

void Module::FindTypesInNamespace(ConstString type_name,
                                  const CompilerDeclContext &parent_decl_ctx,
                                  size_t max_matches, TypeList &type_list);
```

The new Module API is much simpler. It gets rid of all three above
functions and replaces them with:

```
void FindTypes(const TypeQuery &query, TypeResults &results);
```
The `TypeQuery` class contains all of the needed settings:

- The vector<CompilerContext> that allow efficient lookups in the symbol
file classes since they can look at basename matches only realize fully
matching types. Before this any basename that matched was fully realized
only to be removed later by code outside of the SymbolFile layer which
could cause many types to be realized when they didn't need to.
- If the lookup is exact or not. If not exact, then the compiler context
must match the bottom most items that match the compiler context,
otherwise it must match exactly
- If the compiler context match is for clang modules or not. Clang
modules matches include a Module compiler context kind that allows types
to be matched only from certain modules and these matches are not needed
when d oing user type lookups.
- An optional list of languages to use to limit the search to only
certain languages

The `TypeResults` object contains all state required to do the lookup
and store the results:
- The max number of matches
- The set of SymbolFile objects that have already been searched
- The matching type list for any matches that are found

The benefits of this approach are:
- Simpler API, and only one API to implement in SymbolFile classes
- Replaces the FindTypesInNamespace that used a CompilerDeclContext as a
way to limit the search, but this only worked if the TypeSystem matched
the current symbol file's type system, so you couldn't use it to lookup
a type in another module
- Fixes a serious bug in our FindFirstType functions where if we were
searching for "foo::bar", and we found a "baz::bar" first, the basename
would match and we would only fetch 1 type using the basename, only to
drop it from the matching list and returning no results
2023-12-12 16:51:49 -08:00
Michael Buch
4db54e6597 [clang][DebugInfo] Revert "emit definitions for constant-initialized static data-members" (#74580)
This commit reverts the changes in
https://github.com/llvm/llvm-project/pull/71780 and all of its follow-up
patches.

We got reports of the `.debug_names/.debug_gnu_pubnames/gdb_index/etc.`
sections growing by a non-trivial amount for some large projects. While
GCC emits definitions for static data member constants into the Names
index, they do so *only* for explicitly `constexpr` members. We were
indexing *all* constant-initialized const-static members, which is
likely where the significant size difference comes from. However, only
emitting explicitly `constexpr` variables into the index doesn't seem
like a good way forward, since from clang's perspective `const`-static
integrals are `constexpr` too, and that shouldn't be any different in
the debug-info component. Also, as new code moves to `constexpr` instead
of `const` static for constants, such solution would just delay the
growth of the Names index.

To prevent the size regression we revert to not emitting definitions for
static data-members that have no location.

To support access to such constants from LLDB we'll most likely have to
have to make LLDB find the constants by looking at the containing class
first.
2023-12-06 22:13:54 +00:00
Michael Buch
effaf41d20 [lldb][DWARFASTParserClang][NFCI] Make ParsedDWARFTypeAttributes parameter const (#73833) 2023-11-30 05:16:23 +00:00
Michael Buch
bcb621f0a1 [lldb][DWARFASTParserClang][NFC] Remove redundant parameter to AddMethodToObjCObjectType (#73832) 2023-11-30 05:15:57 +00:00
Haojian Wu
439b16e2b3 [LLDB] Respect the DW_AT_alignment attribute. (#73307)
Part of fixes for #72913.

clang emits `DW_AT_alignment` attribute, however LLDB didn't respect it,
resulting in incorrect RecordDecls built by lldb.

This only fixes non-inheritance cases. The inheritance case will be
handled in a follow-up patch.
2023-11-28 12:27:55 +01:00
Michael Buch
70900ec799 [lldb][DWARFASTParserClang][NFC] Clarify comment around static member variable handling (#72495) 2023-11-16 16:09:47 +00:00
Michael Buch
35b10acf20 [lldb][DWARFASTParserClang] DWARFv5: support DW_TAG_variable static data members declarations (#72236)
The accepted DWARFv5 issue 161118.1: "DW_TAG for C++ static data
members" specifies that static data member declaration be described by
DW_TAG_variable. Make sure we recognize such members.

Depends on:
* https://github.com/llvm/llvm-project/pull/72234
* https://github.com/llvm/llvm-project/pull/72235
2023-11-15 11:01:52 +00:00
Michael Buch
743c4fe43c [lldb][DWARFASTParserClang][NFC] Extract static data member decl creation into helper (#72109)
This patch extracts the logic to create a static variable member decl
into a helper. We will use this in an upcoming patch which will need to
call exactly the same logic from a separate part of the DWARF parser.
2023-11-13 19:30:28 +00:00
Michael Buch
f86770aa07 Reland "[lldb][DWARFASTParserClang] Make MemberAttributes const when parsing member DIEs (#71921)"
Changed the recently added `FindConstantOnVariableDefinition` to
not rely on MemberAttributes being non-const.

Original commit message:
"""
This patch removes the Objective-C accessibility workaround added in
5a477cfd90
(rdar://8492646). This allows us to make the local `MemberAttributes`
variable immutable, which is useful for some other work around this
function I was planning on doing.

We don't need the workaround anymore since compiler-support for giving
debuggers access to private ivars was done couple of years later in
d6cb4a858d
(rdar://10997647).

**Testing**

* Test-suite runs cleanly
"""
2023-11-13 06:38:57 +00:00
Michael Buch
c501bf4334 Revert "[lldb][DWARFASTParserClang] Make MemberAttributes const when parsing member DIEs (#71921)"
This reverts commit 576f7ccfa4.

Causes build bot failure because new code started depending
on the non-constness of the MemberAttributes.
2023-11-13 06:16:32 +00:00
Michael Buch
9d587480dc [lldb][DWARFASTParserClang][NFC] Fix build failure
Caused by a badly resolved merge conflict
2023-11-13 06:14:23 +00:00
Michael Buch
576f7ccfa4 [lldb][DWARFASTParserClang] Make MemberAttributes const when parsing member DIEs (#71921)
This patch removes the Objective-C accessibility workaround added in
5a477cfd90
(rdar://8492646). This allows us to make the local `MemberAttributes`
variable immutable, which is useful for some other work around this
function I was planning on doing.

We don't need the workaround anymore since compiler-support for giving
debuggers access to private ivars was done couple of years later in
d6cb4a858d
(rdar://10997647).

**Testing**

* Test-suite runs cleanly
2023-11-13 06:11:05 +00:00
Michael Buch
15c8085202 Reland "[lldb][DWARFASTParserClang] Fetch constant value from variable defintion if available" (#71800)
This patch relands https://github.com/llvm/llvm-project/pull/71004 which
was reverted because the clang change it depends on was reverted.

In addition to the original patch, this PR includes a change to
`SymbolFileDWARF::ParseVariableDIE` to support CU-level variable
definitions that don't have locations, but represent a constant value.
Previously, when debug-maps were available, we would assume that a
variable with "static lifetime" (which in this case means "has a linkage
name") has a valid address, which isn't the case for non-locationed
constants. We could omit this additional change if we stopped attaching
linkage names to global non-locationed constants.

Original commit message:
"""
https://github.com/llvm/llvm-project/pull/71780 proposes moving the
`DW_AT_const_value` on inline static members from the declaration DIE to
the definition DIE. This patch makes sure the LLDB's expression
evaluator can continue to support static initialisers even if the
declaration doesn't have a `DW_AT_const_value` anymore.

Previously the expression evaluator would find the constant for a
VarDecl from its declaration `DW_TAG_member` DIE. In cases where the
initialiser was specified out-of-class, LLDB could find it during symbol
resolution.

However, neither of those will work for constants, since we don't have a
constant attribute on the declaration anymore and we don't have
constants in the symbol table.
"""

Depends on:
* https://github.com/llvm/llvm-project/pull/71780
2023-11-13 06:09:58 +00:00
Haojian Wu
66acd1e4dc [LLDB] Ignore actual-needed artificial members in DWARFASTParserClang::ParseSingleMember (#70779)
Address the FIXME, this will allow lldb to print all fields of the
generated coroutine frame structure.

Fixes #69309.
2023-11-10 10:53:03 +01:00
Hans Wennborg
066eea75d3 Revert "Reland "clang][DebugInfo] Emit global variable definitions for static data members with constant initializers (#70639)""
This casued asserts:

  llvm/lib/IR/Metadata.cpp:689:
  void llvm::MDNode::resolve(): Assertion `isUniqued() && "Expected this to be uniqued"' failed.

See comments on the PR.

This also reverts the dependent follow-up commits, see below.

> When an LLDB user asks for the value of a static data member, LLDB
> starts by searching the Names accelerator table for the corresponding
> variable definition DIE. For static data members with out-of-class
> definitions that works fine, because those get represented as global
> variables with a location and making them eligible to be added to the
> Names table. However, in-class definitions won<E2><80><99>t get indexed because
> we usually don't emit global variables for them. So in DWARF we end
> up with a single `DW_TAG_member` that usually holds the constant
> initializer.  But we don't get a corresponding CU-level
> `DW_TAG_variable` like we do for out-of-class definitions.
>
> To make it more convenient for debuggers to get to the value of
> inline static data members, this patch makes sure we emit definitions
> for static variables with constant initializers the same way we do
> for other static variables. This also aligns Clang closer to GCC,
> which produces CU-level definitions for inline statics and also
> emits these into `.debug_pubnames`.
>
> The implementation keeps track of newly created static data members.
> Then in `CGDebugInfo::finalize`, we emit a global `DW_TAG_variable`
> with a `DW_AT_const_value` for any of those declarations that didn't
> end up with a definition in the `DeclCache`.
>
> The newly emitted `DW_TAG_variable` will look as follows:
> ```
> 0x0000007b:   DW_TAG_structure_type
>                 DW_AT_calling_convention        (DW_CC_pass_by_value)
>                 DW_AT_name      ("Foo")
>                 ...
>
> 0x0000008d:     DW_TAG_member
>                   DW_AT_name    ("i")
>                   DW_AT_type    (0x00000062 "const int")
>                   DW_AT_external        (true)
>                   DW_AT_declaration     (true)
>                   DW_AT_const_value     (4)
>
> Newly added
> vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
>
> 0x0000009a:   DW_TAG_variable
>                 DW_AT_specification     (0x0000008d "i")
>                 DW_AT_const_value       (4)
>                 DW_AT_linkage_name      ("_ZN2t2IiE1iIfEE")
> ```
>
> This patch also drops the `DW_AT_const_value` off of the declaration
> since we now always have it on the definition. This ensures that the
> `DWARFParallelLinker` can type-merge class with static members where
> we couldn't attach the constant on the declaration in some CUs.

This reverts commit 7c3707aea8.
This reverts commit cab0a19467.
This reverts commit 317481b3c8.
This reverts commit 15fc809404.
This reverts commit 470de2bbec.
2023-11-07 15:52:19 +01:00
Michael Buch
470de2bbec Reland "[lldb][DWARFASTParserClang] Fetch constant value from variable defintion if available (#71004)"
https://github.com/llvm/llvm-project/pull/70639 proposes moving the
 `DW_AT_const_value` on inline static members from the declaration DIE to
 the definition DIE. This patch makes sure the LLDB's expression
 evaluator can continue to support static initialisers even if the
 declaration doesn't have a `DW_AT_const_value` anymore.

 Previously the expression evaluator would find the constant for a
 VarDecl from its declaration `DW_TAG_member` DIE. In cases where the
 initialiser was specified out-of-class, LLDB could find it during symbol
 resolution.

 However, neither of those will work for constants, since we don't have a
 constant attribute on the declaration anymore and we don't have
 constants in the symbol table.

 **Testing**

 * If https://github.com/llvm/llvm-project/pull/70639 were to land
 without this patch then most of the `TestConstStaticIntegralMember.py`
 would start failing
2023-11-07 04:54:01 +00:00
Michael Buch
5f86b49146 Revert "[lldb][DWARFASTParserClang] Fetch constant value from variable defintion if available (#71004)"
This reverts commit ef3febadf6.

This caused an LLDB test failure on Linux for `lang/cpp/symbols/TestSymbols.test_dwo`:

```
make: Leaving directory '/home/worker/2.0.1/lldb-x86_64-debian/build/lldb-test-build.noindex/lang/cpp/symbols/TestSymbols.test_dwo'
runCmd: expression -- D::i
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	HandleCommand(command = "expression -- D::i")
1.	<user expression 0>:1:4: current parser token 'i'
2.	<lldb wrapper prefix>:44:1: parsing function body '$__lldb_expr'
3.	<lldb wrapper prefix>:44:1: in compound statement ('{}')
Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):
0  _lldb.cpython-39-x86_64-linux-gnu.so 0x00007fbcfcb08b87
1  _lldb.cpython-39-x86_64-linux-gnu.so 0x00007fbcfcb067ae
2  _lldb.cpython-39-x86_64-linux-gnu.so 0x00007fbcfcb0923f
3  libpthread.so.0                      0x00007fbd07ab7140
```

And a failure in `TestCallStdStringFunction.py` on Linux aarch64:
```
--
Exit Code: -11

Command Output (stdout):
--
lldb version 18.0.0git (https://github.com/llvm/llvm-project.git revision ef3febadf6)
  clang revision ef3febadf6
  llvm revision ef3febadf6

--
Command Output (stderr):
--
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      HandleCommand(command = "expression str")
1.      <lldb wrapper prefix>:45:34: current parser token ';'
2.      <lldb wrapper prefix>:44:1: parsing function body '$__lldb_expr'
3.      <lldb wrapper prefix>:44:1: in compound statement ('{}')
  #0 0x0000ffffb72a149c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lib/python3.8/site-packages/lldb/_[lldb.cpython-38-aarch64-linux-gnu.so](http://lldb.cpython-38-aarch64-linux-gnu.so/)+0x58c749c)
  #1 0x0000ffffb729f458 llvm::sys::RunSignalHandlers() (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lib/python3.8/site-packages/lldb/_[lldb.cpython-38-aarch64-linux-gnu.so](http://lldb.cpython-38-aarch64-linux-gnu.so/)+0x58c5458)
  #2 0x0000ffffb72a1bd0 SignalHandler(int) (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lib/python3.8/site-packages/lldb/_[lldb.cpython-38-aarch64-linux-gnu.so](http://lldb.cpython-38-aarch64-linux-gnu.so/)+0x58c7bd0)
  #3 0x0000ffffbdd9e7dc (linux-vdso.so.1+0x7dc)
  #4 0x0000ffffb71799d8 lldb_private::plugin::dwarf::SymbolFileDWARF::FindGlobalVariables(lldb_private::ConstString, lldb_private::CompilerDeclContext const&, unsigned int, lldb_private::VariableList&) (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lib/python3.8/site-packages/lldb/_[lldb.cpython-38-aarch64-linux-gnu.so](http://lldb.cpython-38-aarch64-linux-gnu.so/)+0x579f9d8)
  #5 0x0000ffffb7197508 DWARFASTParserClang::FindConstantOnVariableDefinition(lldb_private::plugin::dwarf::DWARFDIE) (/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/build/lib/python3.8/site-packages/lldb/_[lldb.cpython-38-aarch64-linux-gnu.so](http://lldb.cpython-38-aarch64-linux-gnu.so/)+0x57bd508)
```
2023-11-06 10:56:49 +00:00
Michael Buch
ef3febadf6 [lldb][DWARFASTParserClang] Fetch constant value from variable defintion if available (#71004)
https://github.com/llvm/llvm-project/pull/70639 proposes moving the
`DW_AT_const_value` on inline static members from the declaration DIE to
the definition DIE. This patch makes sure the LLDB's expression
evaluator can continue to support static initialisers even if the
declaration doesn't have a `DW_AT_const_value` anymore.

Previously the expression evaluator would find the constant for a
VarDecl from its declaration `DW_TAG_member` DIE. In cases where the
initialiser was specified out-of-class, LLDB could find it during symbol
resolution.

However, neither of those will work for constants, since we don't have a
constant attribute on the declaration anymore and we don't have
constants in the symbol table.

**Testing**

* If https://github.com/llvm/llvm-project/pull/70639 were to land
without this patch then most of the `TestConstStaticIntegralMember.py`
would start failing
2023-11-06 10:24:05 +00:00
Vlad Serebrennikov
edd690b02e [clang][NFC] Refactor TagTypeKind (#71160)
This patch converts TagTypeKind into scoped enum. Among other benefits,
this allows us to forward-declare it where necessary.
2023-11-03 21:45:39 +04:00
David Spickett
68fbc8eec3 [lldb][NFC] Use UNUSED_IF_ASSERT_DISABLED instead of (void) cast
Uses of (void) remain where they are for purposes other than an
assert variable.
2023-11-03 14:20:05 +00:00
Vlad Serebrennikov
a8ead56068 [clang][NFC] Rename ArgPassingKind to RecordArgPassingKind (#70955)
During the recent refactoring (b120fe8d32) this enum was moved out of `RecordDecl`. During post-commit review it was found out that its association with `RecordDecl` should be expressed in the name.
2023-11-01 20:38:28 +04:00
Vlad Serebrennikov
b120fe8d32 [clang][NFC] Refactor ArgPassingKind
This patch moves `RecordDecl::ArgPassingKind` to DeclBase.h to namespace scope, so that it's complete at the time bit-field is declared.
2023-11-01 11:49:59 +03:00
Walter Erquinigo
10508b6db7 [LLDB][NFC] Remove DWARFASTParserClang as friend from SymbolFileDWARF (#70157)
This effectively moves a few functions from protected to public. In any
case, for the sake of having a cleaner SymbolFileDWARF API, it's better
if it's not a friend of a one of its consumers, DWARFASTParserClang.
Another effect of this change is that I can use SymbolFileDWARF for the
out-of-tree mojo dwarf parser, which relies on pretty much the same
functions that DWARFASTParserClang needs from SymbolFileDWARF.
2023-10-25 18:04:25 -04:00
Adrian Prantl
49504674db Expose DWARFDIE::GetDeclContext() in lldb_private::Function. (#69981)
I need this API in the Swift plugin, but it seems generally useful
enough to expose it in the main branch.
2023-10-24 10:55:23 -07:00
Augusto Noronha
e6b3a2753b [lldb][NFC] Move DWARFASTParserClang::GetTypeForDIE to DWARFASTParser (#69764) 2023-10-23 17:22:16 -07:00
Augusto Noronha
61c4ee9449 [lldb][NFC] Implement llvm-style RTTI for DWARFASTParser (#69762) 2023-10-23 16:25:18 -07:00
Walter Erquinigo
1673a1ba5d [LLDB][NFC] Create a namespace for the DWARF plugin (#68150)
As a followup of https://github.com/llvm/llvm-project/pull/67851, I'm
defining a new namespace `lldb_plugin::dwarf` for the classes in this
Plugins/SymbolFile/DWARF folder. This change is very NFC and helped me
with exporting the necessary symbols for my out-of-tree language plugin.
The only class that I didn't change is ClangDWARFASTParser, because that
shouldn't be in the same namespace as the generic language-agnostic
dwarf parser.
It would be a good idea if other plugins follow the same namespace
scheme.
2023-10-13 16:51:24 -04:00
Michael Buch
a233a49b60 [lldb][DWARFASTParserClang][NFC] Fix comment regarding static data member detection (#68405)
Fixes misleading comment introduced in
`f74aaca63202cabb512c78fe19196ff348d436a8`
2023-10-06 11:41:37 +01:00
Michael Buch
f74aaca632 [lldb][DWARFASTParserClang] Check DW_AT_declaration to determine static data members (#68300)
**Background**

Prior to DWARFv4, there was no clear normative text on how to handle
static data members. Non-normative text suggested that compilers should
use `DW_AT_external` to mark static data members of structrues/unions.
Clang does this consistently. However, GCC doesn't, e.g., when the
structure/union is in an anonymous namespace (which is C++ standard
conformant). Additionally, GCC never emits `DW_AT_data_member_location`s
for union members (regardless of storage linkage and storage duration).

Since DWARFv5 (issue 161118.1), static data members get emitted as
`DW_TAG_variable`.

LLDB used to differentiate between static and non-static members by
checking the `DW_AT_external` flag and the absence of
`DW_AT_data_member_location`. With
[D18008](https://reviews.llvm.org/D18008) LLDB started to pretend that
union members always have a `0` `DW_AT_data_member_location` by default
(because GCC never emits these locations).

In [D124409](https://reviews.llvm.org/D124409) LLDB stopped checking the
`DW_AT_external` flag to account for the case where GCC doesn't emit the
flag for types in anonymous namespaces; instead we only check for
presence of `DW_AT_data_member_location`s.

The combination of these changes then meant that LLDB would never
correctly detect that a union has static data members.

**Solution**

Instead of unconditionally initializing the `member_byte_offset` to `0`
specifically for union members, this patch proposes to check for both
the absence of `DW_AT_data_member_location` and `DW_AT_declaration`,
which consistently gets emitted for static data members on GCC and
Clang.

We initialize the `member_byte_offset` to `0` anyway if we determine it
wasn't a static. So removing the special case for unions makes this code
simpler to reason about.

Long-term, we should just use DWARFv5's new representation for static
data members.

Fixes #68135
2023-10-06 09:07:20 +01:00
Michael Buch
3a35ca01fc [lldb][DWARFASTParserClang][NFCI] Extract DW_AT_data_member_location calculation logic (#68231)
Currently this non-trivial calculation is repeated multiple times,
making it hard to reason about when the
`byte_offset`/`member_byte_offset` is being set or not.

This patch simply moves all those instances of the same calculation into
a helper function.

We return an optional to remain an NFC patch. Default initializing the
offset would make sense but requires further analysis and can be done in
a follow-up patch.
2023-10-05 10:49:42 +01:00
Fangrui Song
678e3ee123 [lldb] Fix duplicate word typos; NFC
Those fixes were taken from https://reviews.llvm.org/D137338
2023-09-01 21:32:24 -07:00
David Spickett
f8d1209f96 [lldb] Fix Windows on Arm build
Since e84751a215
our bot has been failing:
https://lab.llvm.org/buildbot/#/builders/182/builds/7193

I assume this is just a typo, all tests pass.
2023-08-17 09:56:54 +00:00
Vladimir Makaev
e84751a215 [lldb] Add basic support to Rust enums in TypeSystemClang
LLDB doesn't yet have a TypeSystemRust implemented however it is used to debug Rust applications. Most of the types map well enough to Clang types and there are python formatters implemented to display those types reasonably well in a debugger.

However, Rust enums are completely ignored by LLDB as Clang never emits DW_TAG_variant_part inside DW_TAG_structure_type

This diff adds a parser for DW_TAG_variant_part (Rust-only) that creates a matching valid Clang declaration to the Rust enum. As long as there is enough information and all fields have correct offsets synthetic/summary providers can be implemented to display it correctly when debugging Rust code

Differential Revision: https://reviews.llvm.org/D149213
2023-08-17 02:34:35 +01:00
Jonas Devlieghere
2fcade935a [lldb] Replace radars link with documenting comment (NFC)
This replaces two radar links with improved comments explaining the
underlying issues.

 - The first issue is working around a compiler bug that was fixed in
   f454dfb6b5.
 - The second issue is an invariant that doesn't actually hold. The
   latter was marked as FIXME but there was nothing in the radar about a
   possible alternative solution.

Both radars were closed.
2023-07-30 15:17:16 -07:00
Alex Langford
915256388f [lldb] Refactor ObjCLanguage::MethodName
The goal of this patch is to make it easier to reason about the state of
ObjCLanguage::MethodName. I do that in several ways:
- Instead of using the constructor directly, you go through a factory
  method. It returns a std::optional<MethodName> so either you got an
  ObjCLanguage::MethodName or you didn't. No more checking if it's valid
  to know if you can use it or not.
- ObjCLanguage::MethodName is now immutable. You cannot change its
  internals once it is created.
- ObjCLanguage::MethodName::GetFullNameWithoutCategory previously had a
  parameter that let you get back an empty string if the method had no
  category. Every caller of this method was enabling this behavior so I
  dropped the parameter and made it the default behavior.
- No longer store all the various components of the method name as
  ConstStrings. The relevant `Get` methods now return llvm::StringRefs
  backed by the MethodName's internal storage. The lifetime of these
  StringRefs are tied to the MethodName itself, so if you need to
  persist these you need to create copies.

Differential Revision: https://reviews.llvm.org/D149914
2023-05-18 14:47:33 -07:00
Michael Buch
3c30f22400 [lldb][DWARFASTParserClang] Don't create unnamed bitfields to account for vtable pointer
**Summary**

When filling out the LayoutInfo for a structure with the offsets
from DWARF, LLDB fills gaps in the layout by creating unnamed
bitfields and adding them to the AST. If we don't do this correctly
and our layout has overlapping fields, we will hat an assertion
in `clang::CGRecordLowering::lower()`. Specifically, if we have
a derived class with a VTable and a bitfield immediately following
the vtable pointer, we create a layout with overlapping fields.

This is an oversight in some of the previous cleanups done around this
area.

In `D76808`, we prevented LLDB from creating unnamed bitfields if there
was a gap between the last field of a base class and the start of a bitfield
in the derived class.

In `D112697`, we started accounting for the vtable pointer. The intention
there was to make sure the offset bookkeeping accounted for the
existence of a vtable pointer (but we didn't actually want to create
any AST nodes for it). Now that `last_field_info.bit_size` was being
set even for artifical fields, the previous fix `D76808` broke
specifically for cases where the bitfield was the first member of a
derived class with a vtable (this scenario wasn't tested so we didn't
notice it). I.e., we started creating redundant unnamed bitfields for
where the vtable pointer usually sits. This confused the lowering logic
in clang.

This patch adds a condition to `ShouldCreateUnnamedBitfield` which
checks whether the first field in the derived class is a vtable ptr.

**Testing**

* Added API test case

Differential Revision: https://reviews.llvm.org/D150591
2023-05-16 11:18:09 +01:00
Michael Buch
56eff197d0 [lldb][DWARFASTParserClang][NFC] Extract condition for unnamed bitfield creation into helper function
This patch adds a new private helper
`DWARFASTParserClang::ShouldCreateUnnamedBitfield` which
`ParseSingleMember` whether we should fill the current gap
in a structure layout with unnamed bitfields.

Extracting this logic will allow us to add additional
conditions in upcoming patches without jeoperdizing readability
of `ParseSingleMember`.

We also store some of the boolean conditions in local variables
to make the intent more obvious.

Differential Revision: https://reviews.llvm.org/D150590
2023-05-16 11:18:09 +01:00
Michael Buch
ca64f9af04 [lldb][DWARFASTParserClang][NFC] Simplify unnamed bitfield condition
Minor cleanup of redundant variable initialization and
if-condition. These are leftovers/oversights from previous
cleanup in this area:
* https://reviews.llvm.org/D72953
* https://reviews.llvm.org/D76808

Differential Revision: https://reviews.llvm.org/D150589
2023-05-16 11:18:09 +01:00
Alex Langford
c909b491cb [lldb][NFCI] Change return type of DWARFDebugInfoEntry::GetAttributes
The purpose of this method is to get the list of attributes of a
DebugInfoEntry. Prior to this change we were passing in a mutable
reference to a DWARFAttributes object and having the method fill it in
for us while returning the size of the filled out list. But
instead of doing that, we can just return a `DWARFAttributes` object
ourselves since every caller creates a new list before calling
GetAttributes.

Differential Revision: https://reviews.llvm.org/D150402
2023-05-12 12:17:21 -07:00
Alex Langford
64f1fda29e [lldb][NFCI] Redefine dw_attr_t typedef with llvm::dwarf::Attribute
Similar to dw_form_t, dw_attr_t is typedef'd to be a uint16_t. LLVM
defines their type `llvm::dwarf::Attribute` as an enum backed by a
uint16_t. Switching to the LLVM type buys us type checking and the
requirement of explicit casts.

Differential Revision: https://reviews.llvm.org/D150299
2023-05-12 11:58:50 -07:00
Jonas Devlieghere
c1d55d26d3 [lldb] Let Mangled decide whether a name is mangled or not
We have a handful of places in LLDB where we try to outsmart the logic
in Mangled to determine whether a string is mangled or not. There's at
least one place (*) where we are getting this wrong and causes a subtle
bug. The `cstring_is_mangled` is cheap enough that we should always rely
on it to determine whether a string is mangled or not.

(*) `ObjectFileMachO` assumes that a symbol that starts with a double
underscore (such as `__pthread_kill`) is mangled. That's mostly
harmless, until you use `function.name-without-args` in the frame
format. The formatter calls `Symbol::GetNameNoArguments()` which is a
wrapper around `Mangled::GetName(ePreferDemangledWithoutArguments)`. The
latter will first try using the appropriate language plugin to get the
demangled name without arguments, and if that fails, falls back to
returning the demangled name. Because we forced Mangled to treat the
symbol as a mangled name (even though it's not) there's no demangled
name. The result is that frames don't show any symbol at all.

Differential revision: https://reviews.llvm.org/D148846
2023-04-21 10:23:24 -07:00
Caroline Tice
1fa26e64fd [PATCH][lldb] Fix dereference of null pointer.
The function DWARFASTParserClang::ParsePointerToMemberType attempts to make
two pointers and then immediately tries to dereference them, without
verifying that the pointesr were successfully created. Sometimes the pointer
creation fails, and the dereference then causes a segfault. This add a check
that the pointers are non-null before attempting to dereference them.
2023-04-11 13:33:03 -07:00
David Stenberg
98c3dc3fa7 [lldb] Make GetDIENamesAndRanges() allow 0-valued decl and call lines
In an upcoming patch, D142556, Clang is proposed to be changed to emit
line locations that are inlined at line 0. This clashed with the behavior of
GetDIENamesAndRanges() which used 0 as a default value to determine if
file, line or column numbers had been set. Users of that function then
checked for any non-0 values when setting up the call site:

  if (call_file != 0 || call_line != 0 || call_column != 0)
    [...]

which did not work with the Clang change since all three values then
could be 0.

This changes the function to use std::optional to catch non-set values
instead.

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D142552
2023-03-06 14:23:29 +01:00
Alexander Yermolovich
34a8e6eee6 [LLDB] Enable 64 bit debug/type offset
This came out of from https://discourse.llvm.org/t/dwarf-dwp-4gb-limit/63902
With big binaries we can have .dwp files where .debug_info.dwo section can grow
beyond 4GB. We would like to support this in LLVM and in LLDB.

The plan is to enable manual parsing of cu/tu index in DWARF library
(https://reviews.llvm.org/D137882), and then
switch internal index data structure to 64 bit.
For the second part is to enable 64bit offset support in LLDB with
this patch.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D138618
2023-02-22 11:34:00 -08:00
Kazu Hirata
5e111eb275 Migrate away from the soft-deprecated functions in APInt.h (NFC)
Note that those functions on the left hand side are soft-deprecated in
favor of those on the right hand side:

  getMinSignedBits -> getSignificantBits
  getNullValue     -> getZero
  isNullValue      -> isZero
  isOneValue       -> isOne
2023-02-20 00:58:29 -08:00
Alexander Yermolovich
8116fc592c Revert "[LLDB] Enable 64 bit debug/type offset"
This reverts commit 2062e90aa5.
2023-02-16 17:20:27 -08:00
Alexander Yermolovich
2062e90aa5 [LLDB] Enable 64 bit debug/type offset
This came out of from https://discourse.llvm.org/t/dwarf-dwp-4gb-limit/63902
With big binaries we can have .dwp files where .debug_info.dwo section can grow
beyond 4GB. We would like to support this in LLVM and in LLDB.

The plan is to enable manual parsing of cu/tu index in DWARF library
(https://reviews.llvm.org/D137882), and then
switch internal index data structure to 64 bit.
For the second part is to enable 64bit offset support in LLDB with
this patch.

Depends on D139955

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D138618
2023-02-16 14:46:13 -08:00