We have got customer reporting "v &obj" and "p &obj" reporting different
results.
Turns out it only happens for obj that is itself a reference type which
"v &obj" reports the address of the reference itself instead of the
target object the reference points to. This diverged from C++ semantics.
This PR fixes this issue by returning the address of the dereferenced
object if it is reference type.
A new test is added which fails before.
Co-authored-by: jeffreytan81 <jeffreytan@fb.com>
This is a reduced test case from a crash we've observed in the past. The
assertion that this test triggers is:
```
Assertion failed: ((Pos == ImportedDecls.end() || Pos->second == To) && "Try to import an already imported Decl"), function MapImported, file ASTImporter.cpp, line 10494.
```
In a non-asserts build we crash later on in the ASTImporter. The root
cause is, as the assertion above points out, that we erroneously replace
an existing `From->To` decl mapping with a `To` decl that isn't
complete. Then we try to complete it but it has no definition and we
dereference a nullptr.
The reason this happens is basically what's been described in
https://reviews.llvm.org/D67803?id=220956#1676588
The dylib contains a definition of `Service` which is different to the
one in the main executable. When we start dumping the children of the
variable we're printing, we start completing it's members,
`ASTImport`ing fields in the process. When the ASTImporter realizes
there's been a name conflict (i.e., a structural mismatch on the
`Service` type) it would usually report back an error. However, LLDB
uses `ODRHandlingType::Liberal`, which means we create a new decl for
the ODR'd type instead of re-using the previously mapped decl.
Eventually this leads us to crash.
Ideally we'd be using `ODRHandlingType::Conservative` and warn/error,
though LLDB relies on this in some cases (particularly for
distinguishing template specializations, though maybe there's better a
way to deal with those).
We should really warn the user when this happens and not crash. To avoid
the crash we'd need to know to not create a decl for the ODR violation,
and instead re-use the definition we've previously seen. Though I'm not
yet sure that's viable for all of LLDB's use-cases (where ODR violations
might legimiately occur in a program, e.g., with opaque definitions,
etc.).
This is to fix buildbot failure
https://lab.llvm.org/staging/#/builders/195/builds/4255.
The test expects 'libstdc++' or 'libc++' SO module in the module list.
In case when static linking with libc++ is on by default, none of them
may be present.
Thus, USE_SYSTEM_STDLIB is added to ensure the presence of any of them.
---------
Co-authored-by: Vladimir Vereschaka <vvereschaka@accesssoftek.com>
This commit changes the libc++ frame recognizer to hide implementation
details of libc++ more aggressively. The applied heuristic is rather
straightforward: We consider every function name starting with `__` as
an implementation detail.
This works pretty neatly for `std::invoke`, `std::function`,
`std::sort`, `std::map::emplace` and many others. Also, this should
align quite nicely with libc++'s general coding convention of using the
`__` for their implementation details, thereby keeping the future
maintenance effort low.
However, this heuristic by itself does not work in 100% of the cases:
E.g., `std::ranges::sort` is not a function, but an object with an
overloaded `operator()`, which means that there is no actual call
`std::ranges::sort` in the call stack. Instead, there is a
`std::ranges::__sort::operator()` call. To make sure that we don't hide
this stack frame, we never hide the frame which represents the entry
point from user code into libc++ code
This patch is a reworking of Pete Lawrence's (@PortalPete) proposal
for better expression evaluator error messages:
https://github.com/llvm/llvm-project/pull/80938
Before:
```
$ lldb -o "expr a+b"
(lldb) expr a+b
error: <user expression 0>:1:1: use of undeclared identifier 'a'
a+b
^
error: <user expression 0>:1:3: use of undeclared identifier 'b'
a+b
^
```
After:
```
(lldb) expr a+b
^ ^
│ ╰─ error: use of undeclared identifier 'b'
╰─ error: use of undeclared identifier 'a'
```
This eliminates the confusing `<user expression 0>:1:3` source
location and avoids echoing the expression to the console again, which
results in a cleaner presentation that makes it easier to grasp what's
going on. You can't see it here, bug the word "error" is now also in
color, if so desired.
Depends on https://github.com/llvm/llvm-project/pull/106442.
This patch is a reworking of Pete Lawrence's (@PortalPete) proposal
for better expression evaluator error messages:
https://github.com/llvm/llvm-project/pull/80938
Before:
```
$ lldb -o "expr a+b"
(lldb) expr a+b
error: <user expression 0>:1:1: use of undeclared identifier 'a'
a+b
^
error: <user expression 0>:1:3: use of undeclared identifier 'b'
a+b
^
```
After:
```
(lldb) expr a+b
^ ^
│ ╰─ error: use of undeclared identifier 'b'
╰─ error: use of undeclared identifier 'a'
```
This eliminates the confusing `<user expression 0>:1:3` source
location and avoids echoing the expression to the console again, which
results in a cleaner presentation that makes it easier to grasp what's
going on. You can't see it here, bug the word "error" is now also in
color, if so desired.
Depends on https://github.com/llvm/llvm-project/pull/106442.
Implement operators `<=` and `>=` to explicitly check the comparison
results to be `cmpLessThan` or `cmpEqual` instead of negating the result
of `operators<`.
Fixes#85947
This patch extends TypeQuery matching to support anonymous namespaces. A
new flag is added to control the behavior. In the "strict" mode, the
query must match the type exactly -- all anonymous namespaces included.
The dynamic type resolver in the itanium abi (the motivating use case
for this) uses this flag, as it queries using the name from the
demangles, which includes anonymous namespaces.
This ensures we don't confuse a type with a same-named type in an
anonymous namespace. However, this does *not* ensure we don't confuse
two types in anonymous namespacs (in different CUs). To resolve this, we
would need to use a completely different lookup algorithm, which
probably also requires a DWARF extension.
In the "lax" mode (the default), the anonymous namespaces in the query
are optional, and this allows one search for the type using the usual
language rules (`::A` matches `::(anonymous namespace)::A`).
This patch also changes the type context computation algorithm in
DWARFDIE, so that it includes anonymous namespace information. This
causes a slight change in behavior: the algorithm previously stopped
computing the context after encountering an anonymous namespace, which
caused the outer namespaces to be ignored. This meant that a type like
`NS::(anonymous namespace)::A` would be (incorrectly) recognized as
`::A`). This can cause code depending on the old behavior to misbehave.
The fix is to specify all the enclosing namespaces in the query, or use
a non-exact match.
With this commit, we also hide the implementation details of
`std::invoke`. To do so, the `LibCXXFrameRecognizer` got a couple more
regular expressions.
The regular expression passed into `AddRecognizer` became problematic,
as it was evaluated on the demangled name. Those names also included
result types for C++ symbols. For `std::__invoke` the return type is a
huge `decltype(...)`, making the regular expresison really hard to
write.
Instead, I added support to `AddRecognizer` for matching on the
demangled names without result type and argument types.
By hiding the implementation details of `invoke`, also the back traces
for `std::function` become even nicer, because `std::function` is using
`__invoke` internally.
Co-authored-by: Adrian Prantl <aprantl@apple.com>
Compilers and language runtimes often use helper functions that are
fundamentally uninteresting when debugging anything but the
compiler/runtime itself. This patch introduces a user-extensible
mechanism that allows for these frames to be hidden from backtraces and
automatically skipped over when navigating the stack with `up` and
`down`.
This does not affect the numbering of frames, so `f <N>` will still
provide access to the hidden frames. The `bt` output will also print a
hint that frames have been hidden.
My primary motivation for this feature is to hide thunks in the Swift
programming language, but I'm including an example recognizer for
`std::function::operator()` that I wished for myself many times while
debugging LLDB.
rdar://126629381
Example output. (Yes, my proof-of-concept recognizer could hide even
more frames if we had a method that returned the function name without
the return type or I used something that isn't based off regex, but it's
really only meant as an example).
before:
```
(lldb) thread backtrace --filtered=false
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
* frame #0: 0x0000000100001f04 a.out`foo(x=1, y=1) at main.cpp:4:10
frame #1: 0x0000000100003a00 a.out`decltype(std::declval<int (*&)(int, int)>()(std::declval<int>(), std::declval<int>())) std::__1::__invoke[abi:se200000]<int (*&)(int, int), int, int>(__f=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:149:25
frame #2: 0x000000010000399c a.out`int std::__1::__invoke_void_return_wrapper<int, false>::__call[abi:se200000]<int (*&)(int, int), int, int>(__args=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:216:12
frame #3: 0x0000000100003968 a.out`std::__1::__function::__alloc_func<int (*)(int, int), std::__1::allocator<int (*)(int, int)>, int (int, int)>::operator()[abi:se200000](this=0x000000016fdff280, __arg=0x000000016fdff224, __arg=0x000000016fdff220) at function.h:171:12
frame #4: 0x00000001000026bc a.out`std::__1::__function::__func<int (*)(int, int), std::__1::allocator<int (*)(int, int)>, int (int, int)>::operator()(this=0x000000016fdff278, __arg=0x000000016fdff224, __arg=0x000000016fdff220) at function.h:313:10
frame #5: 0x0000000100003c38 a.out`std::__1::__function::__value_func<int (int, int)>::operator()[abi:se200000](this=0x000000016fdff278, __args=0x000000016fdff224, __args=0x000000016fdff220) const at function.h:430:12
frame #6: 0x0000000100002038 a.out`std::__1::function<int (int, int)>::operator()(this= Function = foo(int, int) , __arg=1, __arg=1) const at function.h:989:10
frame #7: 0x0000000100001f64 a.out`main(argc=1, argv=0x000000016fdff4f8) at main.cpp:9:10
frame #8: 0x0000000183cdf154 dyld`start + 2476
(lldb)
```
after
```
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
* frame #0: 0x0000000100001f04 a.out`foo(x=1, y=1) at main.cpp:4:10
frame #1: 0x0000000100003a00 a.out`decltype(std::declval<int (*&)(int, int)>()(std::declval<int>(), std::declval<int>())) std::__1::__invoke[abi:se200000]<int (*&)(int, int), int, int>(__f=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:149:25
frame #2: 0x000000010000399c a.out`int std::__1::__invoke_void_return_wrapper<int, false>::__call[abi:se200000]<int (*&)(int, int), int, int>(__args=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:216:12
frame #6: 0x0000000100002038 a.out`std::__1::function<int (int, int)>::operator()(this= Function = foo(int, int) , __arg=1, __arg=1) const at function.h:989:10
frame #7: 0x0000000100001f64 a.out`main(argc=1, argv=0x000000016fdff4f8) at main.cpp:9:10
frame #8: 0x0000000183cdf154 dyld`start + 2476
Note: Some frames were hidden by frame recognizers
```
This test causes the assert in clang CodeGen and python crashes with the
error code 0x80000003. See #105019 for more details. Note the similar
test lldb/test/API/lang/c/bitfields/TestBitfields.py is already disabled
on Windows.
This patch allows expressions to reference entities in anonymous
namespaces. Previously this would have resulted in:
```
(lldb) expr foo::FooAnonymousVar
error: <user expression 0>:1:6: no member named 'FooAnonymousVar' in namespace 'foo'
1 | foo::FooAnonymousVar
| ~~~~~^
```
We already allow such lookups through inline namespaces, and for the
purposes of lookup, anonymous namespaces shouldn't behave any different.
Fixes https://github.com/llvm/llvm-project/issues/96963.
In one of my recent PRs I mistakenly had two test-cases with the same
name, preventing one of them to run. Since it's an easy mistake to make
(e.g., copy pasting existing test-cases), I ran following sanity-check
script over `lldb/test/API`, which found couple of tests which were
losing coverage because of this (or in some cases simply had duplicate
tests):
```
import ast
import sys
filename = sys.argv[1]
print(f'Checking {filename}...')
tree = ast.parse(open(filename, 'r').read())
for node in ast.walk(tree):
if not isinstance(node, ast.ClassDef):
continue
func_names = []
for child in ast.iter_child_nodes(node):
if isinstance(child, ast.FunctionDef):
func_names.append(child.name)
seen_func_names = set()
duplicate_func_names = []
for name in func_names:
if name in seen_func_names:
duplicate_func_names.append(name)
else:
seen_func_names.add(name)
if len(duplicate_func_names) != 0:
print(f'Multiple func names found:\n\t{duplicate_func_names}\n\tclass {node.name}\n\tfile: {filename}')
```
This patch fixes these cases.
Adds test that checks whether LLDB correctly infers the
alignment of packed structures. Specifically, the
`InferAlignment` code-path of the `ItaniumRecordLayoutBuilder`
where it assumes that overlapping field offsets imply a
packed structure and thus sets alignment to `1`. See discussion
in https://github.com/llvm/llvm-project/pull/93809.
While here, also added a test-case where we check alignment of
a class whose base has an explicit `DW_AT_alignment
(those don't get transitively propagated in DWARF, but don't seem
like a problem for LLDB).
Lastly, also added an XFAIL-ed tests where the aforementioned
`InferAlignment` kicks in for overlapping fields (but in this
case incorrectly since the structure isn't actually packed).
When PIE is enabled on a platform by default, these tests fail since the
`target variable` command can't read a global string variable value
before running an inferior process.
It fixes the following tests when built with clang on Ubuntu aarch64:
```
commands/target/basic/TestTargetCommand.py
lang/c/global_variables/TestGlobalVariables.py
lang/cpp/char8_t/TestCxxChar8_t.py
```
DWARFDebugInfo only knows how to resolve references in its own file, but
in split dwarf, the index entries will refer to DIEs in the separate
(DWO) file. To resolve the DIERef correctly we'd either need to go
through the SymbolFileDWARF to get the full logic for resolving a
DIERef, or use the fact that ToDIERef already looks up the correct unit
while computing its result.
This patch does the latter.
This bug manifested itself in not being able to find type definitions
for types in namespaces, so I've modified one of our type resolving test
cases to run with debug_names, and added a namespaced class into it (it
originally contained only a top-level class).
This adds a hint to the missing symbols error message to make it easier
to understand what this means to users.
[Reapplies an earlier patch with a test fix.]
Adds a test-case for debugging a program with a
pch chain, that is, the main executable depends
on a pch that itself included another pch.
Currently clang doesn't emit the sekeleton CUs
required for LLDB to track all types on the pch chain. Thus this test is
XFAILed for now.
Layout information for a record gets stored in the `ClangASTImporter`
associated with the `DWARFASTParserClang` that originally parsed the
record. LLDB sometimes moves clang types from one AST to another (in the
reproducer the origin AST was a precompiled-header and the destination
was the AST backing the executable). When clang then asks LLDB to
`layoutRecordType`, it will do so with the help of the
`ClangASTImporter` the type is associated with. If the type's origin is
actually in a different LLDB module (and thus a different
`DWARFASTParserClang` was used to set its layout info), we won't find
the layout info in our local `ClangASTImporter`.
In the reproducer this meant we would drop the alignment info of the
origin type and misread a variable's contents with `frame var` and
`expr`.
There is logic in `ClangASTSource::layoutRecordType` to import an
origin's layout info. This patch re-uses that infrastructure to import
an origin's layout from one `ClangASTImporter` instance to another.
rdar://123274144
This uses [teyit](https://pypi.org/project/teyit/) to modernize asserts,
as recommended by the [unittest release
notes](https://docs.python.org/3.12/whatsnew/3.12.html#id3).
For example, `assertTrue(a == b)` is replaced with `assertEqual(a, b)`.
This produces better error messages, e.g. `error: unexpectedly found 1
and 2 to be different` instead of `error: False`.
assertEquals is a deprecated alias for assertEqual and has been removed
in Python 3.12. This wasn't an issue previously because we used a
vendored version of the unittest module. Now that we use the built-in
version this gets updated together with the Python version used to run
the test suite.
This removes the dependency LLDB API tests have on
lldb/third_party/Python/module/unittest2, and instead uses the standard
one provided by Python.
This does not actually remove the vendored dep yet, nor update the docs.
I'll do both those once this sticks.
Non-trivial changes to call out:
- expected failures (i.e. "bugnumber") don't have a reason anymore, so
those params were removed
- `assertItemsEqual` is now called `assertCountEqual`
- When a test is marked xfail, our copy of unittest2 considers failures
during teardown to be OK, but modern unittest does not. See
TestThreadLocal.py. (Very likely could be a real bug/leak).
- Our copy of unittest2 was patched to print all test results, even ones
that don't happen, e.g. `(5 passes, 0 failures, 1 errors, 0 skipped,
...)`, but standard unittest prints a terser message that omits test
result types that didn't happen, e.g. `OK (skipped=1)`. Our lit
integration parses this stderr and needs to be updated w/ that
expectation.
I tested this w/ `ninja check-lldb-api` on Linux. There's a good chance
non-Linux tests have similar quirks, but I'm not able to uncover those.
The new static linker in Xcode 15 does not emit the necessary
symbols for file static thread local storage, causing this test
to fail when used. The old static linker is still available
as ld-classic in Xcode 15, but it has to be invoked specially, and
the new static linker will be fixed at some point. I may try to
add linker name and versioning information in
lldb/packages/Python/lldbsuite/test/decorators.py like we do with
the compiler / compiler_version, so it can be xfailed for known
problematic static linker name / versions, but until I get that
sorted I'm skipping this test to unblock the CI bots.
This patch fixes the SymbolFilePDBTests::TestMaxMatches(...) by making
it test what it was testing before, see comments in the test case for
details.
It also disables TestUniqueTypes4.py for now until we can debug or fix
why it isn't working.
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
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.
In https://github.com/llvm/llvm-project/pull/73626 we started attaching
`DW_AT_const_value`s on a static data-member's declaration again. In
DWARFv5, those static members are represented with a `DW_TAG_variable`.
When LLDB builds the `ManualDWARFIndex`, it simply iterates over all
DIEs in a CU and puts *any* `DW_TAG_variable` with a constant or
location into the index. So when using the manual index, we can end up
having 2 entries for a static data member in the index, one for the
declaration and one for the definition.
This caused a test failure on Linux (where DWARFv5 is the default and
the tests use the manual index).
This patch loosens the restriction that we find exactly 1 variable.
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.
`638a8393615e911b729d5662096f60ef49f1c65e` removed the `dsym`
condition for older compiler versions which caused the `dwarf`
variants tests to XPASS. This patch reverts to only XFAIL-ing
the `dsym` variant.
`15c80852028ff4020b3f85ee13ad3a2ed4bce3be` added
`test_shadowed_static_inline_members` which isn't supported
on older compiler versions.
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
This patch relands https://github.com/llvm/llvm-project/pull/70639
It was reverted because under certain conditions we triggered an
assertion
in `DIBuilder`. Specifically, in the original patch we called
`EmitGlobalVariable`
at the end of `CGDebugInfo::finalize`, after all the temporary `DIType`s
have
been uniqued. With limited debug-info such temporary nodes would be
created
more frequently, leaving us with non-uniqued nodes by the time we got to
`DIBuilder::finalize`; this violated its pre-condition and caused
assertions to trigger.
To fix this, the latest iteration of the patch moves
`EmitGlobalVariable` to the
beginning of `CGDebugInfo::finalize`. Now, when we create a temporary
`DIType` node as a result of emitting a variable definition, it will get
uniqued
in time. A test-case was added for this scenario.
We also now don't emit a linkage name for non-locationed constants since
LLDB doesn't make use of it anyway.
Original commit message:
"""
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’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.
"""
Dependent changes:
* https://github.com/llvm/llvm-project/pull/71800
