Programs lowered through intermediate IRs lose their position in those
IRs by the time they reach a backend: a DILocation records only the
original source coordinate. Add an optional `irlayers` operand carrying
one coordinate per intermediate level, so a profiler can show the IR
text a program was actually compiled from.
---------
Co-authored-by: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
The DWARF spec allows for the DW_TAG_string_type DIE to contain a
DW_AT_type attribute which can be helpful for supporting non-ASCII
character types in a debugger. This requires adding a DIType member to
DIStringType in LLVM IR, and propagating it to the DWARF generator in
the backend. This is part 1 of 3 to add support for this to flang (Issue
#95440)
See RFC at
https://discourse.llvm.org/t/rfc-disjoint-scope-alias-scope-noalias-domains/91537
This commit adds support for declaring an alias scope domain disjoint.
Disjoint domains are ones where each scope is implicitly `!noalias`
with each other scope in the domain. This is represented by adding an
`i1` into the scope's domain as the second argument, with `i1 true`
representing disjoint scopes and `i1 false` representing the old
non-disjoint behavior. AutoUpgrade mechanisms have been added to add
in the missing `i1 false` to existing metadata.
This commit updates alias analysis to know about disjoint scopes and
updates the function cloner to also clone the alias domain if it's
disjoint (since, as a herd of LLMs discovered, you don't want the old
IR to be noalias with a clone of itself).
Commits to migrate passes to use disjoint scopes where that's an
option are future PRs.
AI disclosure: Claude did the coding on this one, I looked over it and
wrote this commit message
Extend the TBAA auto-upgrade to rewrite old-style scalar field tags
inside !tbaa.struct
to the struct-path aware format. bitcode (MetadataLoader) upgraded to
match the existing top-level !tbaa upgrade.
DWARF v6 adds DW_TAG_property to represent an entity accessed like a
data member but implemented via an accessor, such as an Objective-C
@property backed by an ivar. This adds a DIProperty metadata node,
plumbs it through the IR (LLParser/AsmWriter, bitcode, DIBuilder,
Verifier), and emits DW_TAG_property/DW_AT_property_forward DIEs in
DwarfUnit, anchored on the accessor's own subprogram DIE.
This covers the LLVM IR and DWARF layers only; Clang emission and
LLDB consumption are left for follow-up patches.
Assisted-by: Claude
During bitcode upgrades, if an old DIGlobalVariable is encountered that
contained a DIExpression, a DIGlobalVariableExpression is created for
it. This could happen multiple times. As described in
https://reviews.llvm.org/D26769, it is valid for a DIGlobalVariable to
have multiple DIGlobalVariableExpressions, but the use case for this is
a location that cannot be represented in a single DIExpression, not a
redundant restatement of the same DIExpression.
This patch implements Phase 1 of the
[RFC](https://discourse.llvm.org/t/rfc-enforce-single-operand-format-for-all-enable-metadata-nodes/90571)
"Enforce Single-Operand Format for All .enable Metadata Nodes". The
two-operand boolean form !{!"llvm.loop.distribute.enable", i1 0/1} is
replaced by a single-operand enable/disable pair:
!{!"llvm.loop.distribute.enable"} ; force distribution
!{!"llvm.loop.distribute.disable"} ; suppress distribution
RFC
https://discourse.llvm.org/t/rfc-dwarfdebug-fix-and-improve-handling-imported-entities-types-and-static-local-in-subprogram-and-lexical-block-scopes/68544
Similar to imported declarations and types, the patch tracks
function-local static variables (globals in terms of LLVM IR) in
DISubprogram's 'retainedNodes'. DwarfDebug is adjusted in accordance
with the aforementioned metadata change and provided a support of static
locals scoped by a lexical block. CodeViewDebug is modified to collect
global variables from DISubprogram's 'retainedNodes' too.
The patch assumes that DICompileUnit's 'globals' no longer tracks static
locals and DwarfDebug would assert if any locally-scoped variables get
placed there.
This change has already been reviewed in
https://reviews.llvm.org/D144008, but I’m opening a new PR because it
has been a while since it was approved. Additional logic was added to
CloneFunction to deal with DISubprograms that have static locals: if
such a subprogram is cloned, DIGlobalVariableExpressions are removed
from retainedNodes of the clone. This is consistent with the current
behavior, in which DIGlobalVariableExpressions are not cloned.
Authored-by: Kristina Bessonova <kbessonova@accesssoftek.com>
Co-authored-by: Tobias Gysi <tobias.gysi@nextsilicon.com>
This PR introduces an LLVM vendor DWARF attribute on compile units that
carries an optional target-specific language dialect enumerator,
distinct from DW_LANG_*. The intent of this addition is to allow a DWARF
consumer to differentiate the source programming language from the
programming model (e.g., CUDA/SIMT, Tile, etc.). This concept could also
be used to differentiate OpenMP, or other parallel models, from host
language.
As older languages adopt newer programming models, there's no need to
introduce a new language enumerator to encode that representation;
rather, the model can be encoded as a dialect and treated as a
refinement to the source language being compiled. For ease of
extensibility, we've decided to represent the value of this new dialect
attribute as a string.
Code/comments/description were developed with LLM assistance.
---------
Co-authored-by: Cursor <cursoragent@cursor.com>
The bitcode upgrade process for DISubprogram was fragile and depended on
the exact order in which DICompileUnit, DISubprogram, and the list of
DISubprograms were emitted. This would work out okay with bitcode
written by standard LLVM, but was not a rule that the old format had.
This commit makes the upgrade process work when these metadata nodes are
emitted in any order, and updates the existing upgrade-subprogram.ll
test to cover all orders. The corresponding .bc file was written by a
patched version of LLVM 3.7 that provides a hook to force nodes to be
emitted in a specific order and can be inspected with llvm-bcanalyzer
--dump.
DIBasicType derives from DIType and so it already has slots to store the
scope and location of the type. However, the DIBasicType constructor
(and corresponding DIBuilder method) does not expose this, presumably
because it is not needed by C or C++.
In Ada it is more common to create one's own basic type. So, for Ada
exposing this functionality would be handy.
This patch adds a new overload of DIBuilder::createBasicType to allow
this. Because only Ada uses fixed point types, the patch simply updates
these DIBuilder methods unconditionally.
Note that DwarfUnit already handles this scenario and so no changes were
needed there.
This is an attempt to merge https://reviews.llvm.org/D144006 with LTO
fix.
The last merge attempt was
https://github.com/llvm/llvm-project/pull/75385.
The issue with it was investigated in
https://github.com/llvm/llvm-project/pull/75385#issuecomment-2386684121.
The problem happens when
1. Several modules are being linked.
2. There are several DISubprograms that initially belong to different
modules but represent the same source code function (for example, a
function included from the same source code file).
3. Some of such DISubprograms survive IR linking. It may happen if one
of them is inlined somewhere or if the functions that have these
DISubprograms attached have internal linkage.
4. Each of these DISubprograms has a local type that corresponds to the
same source code type. These types are initially from different modules,
but have the same ODR identifier.
If the same (in the sense of ODR identifier/ODR uniquing rules) local
type is present in two modules, and these modules are linked together,
the type gets uniqued. A DIType, that happens to be loaded first,
survives linking, and the references on other types with the same ODR
identifier from the modules loaded later are replaced with the
references on the DIType loaded first. Since defintion subprograms, in
scope of which these types are located, are not deduplicated, the linker
output may contain multiple DISubprogram's having the same (uniqued)
type in their retainedNodes lists.
Further compilation of such modules causes crashes.
To tackle that,
* previous solution to handle LTO linking with local types in
retainedNodes is removed (cloneLocalTypes() function),
* for each loaded distinct (definition) DISubprogram, its retainedNodes
list is scanned after loading, and DITypes with a scope of another
subprogram are removed. If something from a Function corresponding to
the DISubprogram references uniqued type, we rely on cross-CU links.
Additionally:
* a check is added to Verifier to report about local types located in a
wrong retainedNodes list,
Original commit message follows.
---------
RFC https://discourse.llvm.org/t/rfc-dwarfdebug-fix-and-improve-handling-imported-entities-types-and-static-local-in-subprogram-and-lexical-block-scopes/68544
Similar to imported declarations, the patch tracks function-local types in
DISubprogram's 'retainedNodes' field. DwarfDebug is adjusted in accordance with
the aforementioned metadata change and provided a support of function-local
types scoped within a lexical block.
The patch assumes that DICompileUnit's 'enums field' no longer tracks local
types and DwarfDebug would assert if any locally-scoped types get placed there.
Authored-by: Kristina Bessonova <kbessonova@accesssoftek.com>
Co-authored-by: Jeremy Morse <jeremy.morse@sony.com>
DW_TAG_base_type DIEs are permitted to have both byte_size and bit_size
attributes "If the value of an object of the given type does not fully
occupy the storage described by a byte size attribute"
* Add DataSizeInBits to DIBasicType (`DIBasicType(... dataSize: n ...)` in IR).
* Change Clang to add DataSizeInBits to _BitInt type metadata.
* Change LLVM to add DW_AT_bit_size to base_type DIEs that have non-zero
DataSizeInBits.
TODO: Do we need to emit DW_AT_data_bit_offset for big endian targets?
See discussion on the PR.
Fixes [#61952](https://github.com/llvm/llvm-project/issues/61952)
---------
Co-authored-by: David Stenberg <david.stenberg@ericsson.com>
Depends on:
* https://github.com/llvm/llvm-project/pull/165401
We weren't testing `DIObjCProperty` roundtripping. So this was never
caught.
The consequence of this is that the `setter:` would have the getter name
and `getter:` would have the setter name.
This patch sets up `DICompileUnit` to support the DWARFv6
`DW_AT_language_name` and `DW_AT_language_version` attributes (which are
set to replace `DW_AT_language`). This patch changes the
`DICompileUnit::SourceLanguage` field type to a `DISourceLanguageName`
that encapsulates the notion of "versioned vs. unversioned name". A
"versioned" name is one that has an associated version stored separately
in `DISourceLanguageName::Version`.
This patch just changes all the clients of the `getSourceLanguage` API
to the expect a `DISourceLanguageName`. Currently they all just `assert`
(via `DISourceLanguageName::getUnversionedName`) that we're dealing with
"unversioned names" (i.e., the pre-DWARFv6 language codes). In follow-up
patches (e.g., draft is at
https://github.com/llvm/llvm-project/pull/162261), when we start
emitting versioned language codes, the `getUnversionedName` calls can
then be adjusted to `getName`.
**Implementation considerations**
* We could have added a new member to `DICompileUnit` alongside the
existing `SourceLanguage` field. I don't think this would have made the
transition any simpler (clients would still need to be aware of
"versioned" vs. "unversioned" language names). I felt that encapsulating
this inside a `DISourceLanguageName` was easier to reason about for
maintainers.
* Currently DISourceLanguageName is a `12` byte structure. We could
probably pack all the info inside a `uint64_t` (16-bits for the name,
32-bits for the version, 1-bit for answering the `hasVersionedName`).
Just to keep the prototype simple I used a `std::optional`. But since
the guts of the structure are hidden, we can always change the layout to
a more compact representation instead.
**How to review**
* The new `DISourceLanguageName` structure is defined in
`DebugInfoMetadata.h`. All the other changes fall out from changing the
`DICompileUnit::SourceLanguage` from `unsigned` to
`DISourceLanguageName`.
- Remove forward declaration of `llvm::Argument` and include Argument.h
instead.
- Restrict scope of anonymous namespaces to just class declarations.
- Move local static function out of anonymous namespace.
- Remove a redundant assert when indexing a vector.
In order to better see what's going on during ThinLTO linking, this PR
adds more profile tags when using `--time-trace` on a `lld-link.exe`
invocation.
After PR, linking `clang.exe`:
<img width="3839" height="2026" alt="Capture d’écran 2025-09-02 082021"
src="https://github.com/user-attachments/assets/bf0c85ba-2f85-4bbf-a5c1-800039b56910"
/>
Linking a custom (Unreal Engine game) binary gives a completly
different picture, probably because of using Unity files, and the sheer
amount of input files (here, providing over 60 GB of .OBJs/.LIBs).
<img width="1940" height="1008" alt="Capture d’écran 2025-09-02 102048"
src="https://github.com/user-attachments/assets/60b28630-7995-45ce-9e8c-13f3cb5312e0"
/>
Serialise key-instruction fields of DILocations and DISubprograms into
and outof bitcode, add tests. debug-info bitcode sizes grow, but it
balances out given an earlier size optimisation in 51f4e2c.
Co-authored-by: Orlando Cazalet-Hyams <orlando.hyams@sony.com>
RFC on discourse:
https://discourse.llvm.org/t/rfc-debug-info-for-coroutine-suspension-locations-take-2/86606
With this commit, we add `DILabel` debug infos to the resume points of a
coroutine. Those labels can be used by debugging scripts to figure out
the exact line and column at which a coroutine was suspended by looking
up current `__coro_index` value inside the coroutines frame, and then
searching for the corresponding label inside the coroutine's resume
function.
The DWARF information generated for such a label looks like:
```
0x00000f71: DW_TAG_label
DW_AT_name ("__coro_resume_1")
DW_AT_decl_file ("generator-example.cpp")
DW_AT_decl_line (5)
DW_AT_decl_column (3)
DW_AT_artificial (true)
DW_AT_LLVM_coro_suspend_idx (0x01)
DW_AT_low_pc (0x00000000000019be)
```
The labels can be mapped to their corresponding `__coro_idx` values
either via their naming convention `__coro_resume_<N>` or using the new
`DW_AT_LLVM_coro_suspend_idx` attribute. In gdb, those line numebrs can
be looked up using `info line -function my_coroutine -label
__coro_resume_1`. LLDB unfortunately does not understand DW_TAG_label
debug information, yet.
Given this is an artificial compiler-generated label, I did apply the
DW_AT_artificial tag to it. The DWARFv5 standard only allows that tag on
type and variable definitions, but this is a natural extension and was
also blessed in the RFC on discourse.
Also, this commit adds `DW_AT_decl_column` to labels, not only for
coroutines but also for normal C and C++ labels. While not strictly
necessary, I am doing so now because it would be harder to do so later
without breaking the binary LLVM-IR format
Drive-by fixes: While reading the existing test cases to understand how
to write my own test case, I did a couple of small typo fixes and
comment improvements
PR #141106 changed the debuginfo metdata to allow dynamic bit offsets
and sizes. This caused a crash in lld when using LTO.
The problem is that lazyLoadOneMetadata assumes that the metadata in
question can be cast to MDNode; but in the typical case where the offset
is a constant, this is not true.
This patch changes this spot to allow non-MDNodes through.
The included test case comes from the report in #141106.
In Ada, a record type can have a non-constant size, and a field can
appear at a non-constant bit offset in a record.
To support this, this patch changes DIType to record the size and offset
using metadata, rather than plain integers. In addition to a constant
offset, both DIVariable and DIExpression are now supported here.
One thing of note in this patch is the choice of how exactly to
represent a non-constant bit offset, with the difficulty being that
DWARF 5 does not support this. DWARF 3 did have a way to support a
non-constant byte offset, combined with a constant bit offset within the
byte, but this was deprecated in DWARF 4 and removed from DWARF 5.
This patch takes a simple approach: a DWARF extension allowing the use
of an expression with DW_AT_data_bit_offset. There is a corresponding
DWARF issue, see https://dwarfstd.org/issues/250501.1.html. The main
reason for this approach is that it keeps API simplicity: just a single
value is needed, rather than having separate data describing the byte
offset and the bit within the byte.
These are identified by misc-include-cleaner. I've filtered out those
that break builds. Also, I'm staying away from llvm-config.h,
config.h, and Compiler.h, which likely cause platform- or
compiler-specific build failures.
This adds DWARF generation for fixed-point types. This feature is needed
by Ada.
Note that a pre-existing GNU extension is used in one case. This has
been emitted by GCC for years, and is needed because standard DWARF is
otherwise incapable of representing these types.
In Ada, an array can be packed and the elements can take less space than
their natural object size. For example, for this type:
type Packed_Array is array (4 .. 8) of Boolean;
pragma pack (Packed_Array);
... each element of the array occupies a single bit, even though the
"natural" size for a Boolean in memory is a byte.
In DWARF, this is represented by putting a DW_AT_bit_stride onto the
array type itself.
This patch adds a bit stride to DICompositeType so that gnat-llvm can
emit DWARF for these sorts of arrays.
An Ada program can have types that are subranges of other types. This
patch adds a new DIType node, DISubrangeType, to represent this concept.
I considered extending the existing DISubrange to do this, but as
DISubrange does not derive from DIType, that approach seemed more
disruptive.
A DISubrangeType can be used both as an ordinary type, but also as the
type of an array index. This is also important for Ada.
Ada subrange types can also be stored using a bias. Representing this in
the DWARF required the use of an extension. GCC has been emitting this
extension for years, so I've reused it here.
When creating `EnumDecl`s from DWARF for Objective-C `NS_ENUM`s, the
Swift compiler tries to figure out if it should perform "swiftification"
of that enum (which involves renaming the enumerator cases, etc.). The
heuristics by which it determines whether we want to swiftify an enum is
by checking the `enum_extensibility` attribute (because that's what
`NS_ENUM` pretty much are). Currently LLDB fails to attach the
`EnumExtensibilityAttr` to `EnumDecl`s it creates (because there's not
enough info in DWARF to derive it), which means we have to fall back to
re-building Swift modules on-the-fly, slowing down expression evaluation
substantially. This happens around
https://github.com/swiftlang/swift/blob/4b3931c8ce437b3f13f245e6423f95c94a5876ac/lib/ClangImporter/ImportEnumInfo.cpp#L37-L59
To speed up Swift exression evaluation, this patch proposes encoding the
C/C++/Objective-C `enum_extensibility` attribute in DWARF via a new
`DW_AT_APPLE_ENUM_KIND`. This would currently be only used from the LLDB
Swift plugin. But may be of interest to other language plugins as well
(though I haven't come up with a concrete use-case for it outside of
Swift).
I'm open to naming suggestions of the various new attributes/attribute
constants proposed here. I tried to be as generic as possible if we
wanted to extend it to other kinds of enum properties (e.g., flag
enums).
The new attribute would look as follows:
```
DW_TAG_enumeration_type
DW_AT_type (0x0000003a "unsigned int")
DW_AT_APPLE_enum_kind (DW_APPLE_ENUM_KIND_Closed)
DW_AT_name ("ClosedEnum")
DW_AT_byte_size (0x04)
DW_AT_decl_file ("enum.c")
DW_AT_decl_line (23)
DW_TAG_enumeration_type
DW_AT_type (0x0000003a "unsigned int")
DW_AT_APPLE_enum_kind (DW_APPLE_ENUM_KIND_Open)
DW_AT_name ("OpenEnum")
DW_AT_byte_size (0x04)
DW_AT_decl_file ("enum.c")
DW_AT_decl_line (27)
```
Absence of the attribute means the extensibility of the enum is unknown
and abides by whatever the language rules of that CU dictate.
This does feel like a big hammer for quite a specific use-case, so I'm
happy to discuss alternatives.
Alternatives considered:
* Re-using an existing DWARF attribute to express extensibility. E.g., a
`DW_TAG_enumeration_type` could have a `DW_AT_count` or
`DW_AT_upper_bound` indicating the number of enumerators, which could
imply closed-ness. I felt like a dedicated attribute (which could be
generalized further) seemed more applicable. But I'm open to re-using
existing attributes.
* Encoding the entire attribute string (i.e., `DW_TAG_LLVM_annotation
("enum_extensibility((open))")`) on the `DW_TAG_enumeration_type`. Then
in LLDB somehow parse that out into a `EnumExtensibilityAttr`. I haven't
found a great API in Clang to parse arbitrary strings into AST nodes
(the ones I've found required fully formed C++ constructs). Though if
someone knows of a good way to do this, happy to consider that too.
Add a specification attribute to LLVM DebugInfo, which is analogous
to DWARF's DW_AT_specification. According to the DWARF spec:
"A debugging information entry that represents a declaration that
completes another (earlier) non-defining declaration may have a
DW_AT_specification attribute whose value is a reference to the
debugging information entry representing the non-defining declaration."
This patch allows types to be specifications of other types. This is
used by Swift to represent generic types. For example, given this Swift
program:
```
struct MyStruct<T> {
let t: T
}
let variable = MyStruct<Int>(t: 43)
```
The Swift compiler emits (roughly) an unsubtituted type for MyStruct<T>:
```
DW_TAG_structure_type
DW_AT_name ("MyStruct")
// "$s1w8MyStructVyxGD" is a Swift mangled name roughly equivalent to
// MyStruct<T>
DW_AT_linkage_name ("$s1w8MyStructVyxGD")
// other attributes here
```
And a specification for MyStruct<Int>:
```
DW_TAG_structure_type
DW_AT_specification (<link to "MyStruct">)
// "$s1w8MyStructVySiGD" is a Swift mangled name equivalent to
// MyStruct<Int>
DW_AT_linkage_name ("$s1w8MyStructVySiGD")
DW_AT_byte_size (0x08)
// other attributes here
```
An extra inhabitant is a bit pattern that does not represent a valid
value for instances of a given type. The number of extra inhabitants is
the number of those bit configurations.
This is used by Swift to save space when composing types. For example,
because Bool only needs 2 bit patterns to represent all of its values
(true and false), an Optional<Bool> only occupies 1 byte in memory by
using a bit configuration that is unused by Bool. Which bit patterns are
unused are part of the ABI of the language.
Since Swift generics are not monomorphized, by using dynamic libraries
you can have generic types whose size, alignment, etc, are known only
at runtime (which is why this feature is needed).
This patch adds num_extra_inhabitants to LLVM-IR debug info and in DWARF
as an Apple extension.
It is almost always simpler to use {} instead of std::nullopt to
initialize an empty ArrayRef. This patch changes all occurrences I could
find in LLVM itself. In future the ArrayRef(std::nullopt_t) constructor
could be deprecated or removed.
Extend `DIBasicType` and `DISubroutineType` with additional field
`annotations`, e.g. as below:
```
!5 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed, annotations: !6)
!6 = !{!7}
!7 = !{!"btf:type_tag", !"tag1"}
```
The field would be used by BPF backend to generate DWARF attributes
corresponding to `btf_type_tag` type attributes, e.g.:
```
0x00000029: DW_TAG_base_type
DW_AT_name ("int")
DW_AT_encoding (DW_ATE_signed)
DW_AT_byte_size (0x04)
0x0000002d: DW_TAG_LLVM_annotation
DW_AT_name ("btf:type_tag")
DW_AT_const_value ("tag1")
```
Such DWARF entries would be used to generate BTF definitions by tools
like [pahole](https://github.com/acmel/dwarves).
Note: similar fields with similar purposes are already present in
DIDerivedType and DICompositeType.
Currently "btf_type_tag" attributes are represented in debug information
as 'annotations' fields in DIDerivedType with DW_TAG_pointer_type tag.
The annotation on a pointer corresponds to pointee having the attributes
in the final BTF.
The discussion in
[thread](https://lore.kernel.org/bpf/87r0w9jjoq.fsf@oracle.com/) came to
conclusion, that such annotations should apply to the annotated type
itself. Hence the necessity to extend `DIBasicType` & `DISubroutineType`
types with 'annotations' field to represent cases like below:
```
int __attribute__((btf_type_tag("foo"))) bar;
```
This was previously tracked as differential revision:
https://reviews.llvm.org/D143966
This is the major rename patch that prior patches have built towards.
The DPValue class is being renamed to DbgVariableRecord, which reflects
the updated terminology for the "final" implementation of the RemoveDI
feature. This is a pure string substitution + clang-format patch. The
only manual component of this patch was determining where to perform
these string substitutions: `DPValue` and `DPV` are almost exclusively
used for DbgRecords, *except* for:
- llvm/lib/target, where 'DP' is used to mean double-precision, and so
appears as part of .td files and in variable names. NB: There is a
single existing use of `DPValue` here that refers to debug info, which
I've manually updated.
- llvm/tools/gold, where 'LDPV' is used as a prefix for symbol
visibility enums.
Outside of these places, I've applied several basic string
substitutions, with the intent that they only affect DbgRecord-related
identifiers; I've checked them as I went through to verify this, with
reasonable confidence that there are no unintended changes that slipped
through the cracks. The substitutions applied are all case-sensitive,
and are applied in the order shown:
```
DPValue -> DbgVariableRecord
DPVal -> DbgVarRec
DPV -> DVR
```
Following the previous rename patches, it should be the case that there
are no instances of any of these strings that are meant to refer to the
general case of DbgRecords, or anything other than the DPValue class.
The idea behind this patch is therefore that pure string substitution is
correct in all cases as long as these assumptions hold.
If --load-bitcode-into-experimental-debuginfo-iterators is true then debug
intrinsics are auto-upgraded to DbgRecords (the new debug info format).
The upgrade is trivial because the two representations are semantically
identical. llvm.dbg.value with 4 operands and llvm.dbg.addr intrinsics are
upgraded in the same way as usual, but converted directly into DbgRecords
instead of debug intrinsics.
Reland #82363 after fixing build failure
https://lab.llvm.org/buildbot/#/builders/5/builds/41428.
Memory sanitizer detects usage of `RawData` union member which is not
filled directly. Instead, the code relies on filling `Data` union
member, which is a struct consisting of signing schema parameters.
According to https://en.cppreference.com/w/cpp/language/union, this is
UB:
"It is undefined behavior to read from the member of the union that
wasn't most recently written".
Instead of relying on compiler allowing us to do dirty things, do not
use union and only store `RawData`. Particular ptrauth parameters are
obtained on demand via bit operations.
Original PR description below.
Emit `__ptrauth`-qualified types as `DIDerivedType` metadata nodes in IR
with tag `DW_TAG_LLVM_ptrauth_type`, baseType referring to the type
which has the qualifier applied, and the following parameters
representing the signing schema:
- `ptrAuthKey` (integer)
- `ptrAuthIsAddressDiscriminated` (boolean)
- `ptrAuthExtraDiscriminator` (integer)
- `ptrAuthIsaPointer` (boolean)
- `ptrAuthAuthenticatesNullValues` (boolean)
Co-authored-by: Ahmed Bougacha <ahmed@bougacha.org>
Emit `__ptrauth`-qualified types as `DIDerivedType` metadata nodes in IR
with tag `DW_TAG_LLVM_ptrauth_type`, baseType referring to the type
which has the qualifier applied, and the following parameters
representing the signing schema:
- `ptrAuthKey` (integer)
- `ptrAuthIsAddressDiscriminated` (boolean)
- `ptrAuthExtraDiscriminator` (integer)
- `ptrAuthIsaPointer` (boolean)
- `ptrAuthAuthenticatesNullValues` (boolean)
Co-authored-by: Ahmed Bougacha <ahmed@bougacha.org>
This fixes some cases of missing debuginfo caused by an interaction
between:
https://github.com/llvm/llvm-project/commit/f0d66559ea345db4b2116cae044aaf3399d7e829,
which drops the identifier from a DICompositeType in the module
containing its
vtable.
and
https://github.com/llvm/llvm-project/commit/a61f5e379675732666744bcba25efbc9922e016a,
which causes ThinLTO to import composite types as declarations when they
have
an identifier.
If a virtual class's DICompositeType has no identifier due to the first
change,
and contains a nested anonymous type which does have an identifier, then
the
second change can cause ThinLTO to output the classes's DICompositeType
as a
type definition that links to a non-defining declaration for the nested
type.
Since the nested anonyous type does not have a name, debuggers are
unable to
find the definition for the declaration.
Repro case:
```
cat > a.h <<EOF
class A {
public:
A();
virtual ~A();
private:
union {
int val;
};
};
EOF
cat > a.cc <<EOF
#include "a.h"
A::A() { asm(""); }
A::~A() {}
EOF
cat > main.cc <<EOF
#include "a.h"
int main(int argc, char **argv) {
A a;
return 0;
}
EOF
clang++ -O2 -g -flto=thin -mllvm -force-import-all main.cc a.cc
gdb ./a.out -batch -ex 'pt /rmt A'
```
The gdb command outputs:
```
type = class A {
private:
union {
<incomplete type>
};
}
```
and dwarfdump -i a.out shows a DW_TAG_class_type for A with an
incomplete union
type (note that there is also a duplicate entry with the full union type
that
comes after).
```
< 1><0x0000001e> DW_TAG_class_type
DW_AT_containing_type <0x0000001e>
DW_AT_calling_convention DW_CC_pass_by_reference
DW_AT_name (indexed string: 0x00000007)A
DW_AT_byte_size 0x00000010
DW_AT_decl_file 0x00000001 /path/to/./a.h
DW_AT_decl_line 0x00000001
...
< 2><0x0000002f> DW_TAG_member
DW_AT_type <0x00000037>
DW_AT_decl_file 0x00000001 /path/to/./a.h
DW_AT_decl_line 0x00000007
DW_AT_data_member_location 8
< 2><0x00000037> DW_TAG_union_type
DW_AT_export_symbols yes(1)
DW_AT_calling_convention DW_CC_pass_by_value
DW_AT_declaration yes(1)
```
This change works around this by making ThinLTO always import full
definitions
for anonymous types.
