Reapply PR142507 with fix for test: add in the same x86_64-linux
requirement as other tests as the stack ids are currently computed
differently on big endian systems. This will be investigated separately.
In order to allow selective reporting of context hinting during the LTO
link, and in the future to allow selective more aggressive cloning, add
an option to specify a minimum percent of the max cold size in the
profile summary. Contexts that meet that threshold will get context size
info metadata (and ThinLTO summary information) on the associated
allocations.
Specifying -memprof-report-hinted-sizes during the pre-LTO compile step
will continue to cause all contexts to receive this metadata. But
specifying -memprof-report-hinted-sizes only during the LTO link will
cause only those that meet the new threshold and have the metadata to
get reported.
To support this, because the alloc info summary and associated bitcode
requires the context size information to be in the same order as the
other context information, 0s are inserted for contexts without this
metadata. The bitcode writer uses a more compact format for the context
ids to allow better compression of the 0s.
As part of this change several helper methods are added to query whether
metadata contains context size info on any or all contexts.
In order to allow selective reporting of context hinting during the LTO
link, and in the future to allow selective more aggressive cloning, add
an option to specify a minimum percent of the max cold size in the
profile summary. Contexts that meet that threshold will get context size
info metadata (and ThinLTO summary information) on the associated
allocations.
Specifying -memprof-report-hinted-sizes during the pre-LTO compile step
will continue to cause all contexts to receive this metadata. But
specifying -memprof-report-hinted-sizes only during the LTO link will
cause only those that meet the new threshold and have the metadata to
get reported.
To support this, because the alloc info summary and associated bitcode
requires the context size information to be in the same order as the
other context information, 0s are inserted for contexts without this
metadata. The bitcode writer uses a more compact format for the context
ids to allow better compression of the 0s.
As part of this change several helper methods are added to query whether
metadata contains context size info on any or all contexts.
## Purpose
This patch is one in a series of code-mods that annotate LLVM’s public
interface for export. This patch annotates the `llvm/AsmParser`,
`llvm/BinaryFormat`, `llvm/Bitcode` and `llvm/Bitstream libraries. These
annotations currently have no meaningful impact on the LLVM build;
however, they are a prerequisite to support an LLVM Windows DLL (shared
library) build.
## Background
This effort is tracked in #109483. Additional context is provided in
[this
discourse](https://discourse.llvm.org/t/psa-annotating-llvm-public-interface/85307),
and documentation for `LLVM_ABI` and related annotations is found in the
LLVM repo
[here](https://github.com/llvm/llvm-project/blob/main/llvm/docs/InterfaceExportAnnotations.rst).
The bulk of these changes were generated automatically using the
[Interface Definition Scanner (IDS)](https://github.com/compnerd/ids)
tool, followed formatting with `git clang-format`.
The following manual adjustments were also applied after running IDS on
Linux:
- Add `LLVM_ABI_FRIEND` to friend member functions declared with
`LLVM_ABI`
- Add `LLVM_ABI` symbols that require export but are not declared in
headers
## Validation
Local builds and tests to validate cross-platform compatibility. This
included llvm, clang, and lldb on the following configurations:
- Windows with MSVC
- Windows with Clang
- Linux with GCC
- Linux with Clang
- Darwin with Clang
Fixes errors about duplicate PHI edges when the input had duplicates
with constexprs in them. The constexpr translation makes new basic
blocks, causing the verifier to complain about duplicate entries in PHI
nodes.
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.
With this change, some callers get to use StringRef::starts_with.
I'm planning to teach getAsmString to return StringRef also, but
I'ld like to keep that separate from this patch.
Since we currently only use the context information in the alloc info
summary in the LTO backend for assertion checking, there is no need to
write this into the combined summary index for distributed ThinLTO for
NDEBUG builds. Put this under a new -combined-index-memprof-context
option which is off by default for NDEBUG.
The advantage is that we save time (not having to sort in preparation
for building the radix trees), and space in the generated bitcode files.
We could also do so for the callsite info records, but those are smaller
and less expensive to prepare.
Reapply "IR: Remove uselist for constantdata (#137313)"
This reverts commit 5936c02c8b9c6d1476f7830517781ce8b6e26e75.
Fix checking uselists of constants in assume bundle queries
This is a resurrected version of the patch attached to this RFC:
https://discourse.llvm.org/t/rfc-constantdata-should-not-have-use-lists/42606
In this adaptation, there are a few differences. In the original patch, the Use's
use list was replaced with an unsigned* to the reference count in the value. This
version leaves them as null and leaves the ref counting only in Value.
Remove use-lists from instances of ConstantData (which are shared
across modules and have no operands).
To continue supporting most of the use-list API, store a ref-count in
place of the use-list; this is for API like Value::use_empty and
Value::hasNUses. Operations that actually need the use-list -- like
Value::use_begin -- will assert.
This change has three benefits:
1. The compiler output cannot in any way depend on the use-list order
of instances of ConstantData.
2. There's no use-list traffic when adding and removing simple
constants from operand lists (although there is ref-count traffic;
YMMV).
3. It's cheaper to serialize use-lists (since we're no longer
serializing the use-list order of things like i32 0).
The downside is that you can't look at all the users of ConstantData,
but traversals of users of i32 0 are already ill-advised.
Possible follow-ups:
- Track if an instance of a ConstantVector/ConstantArray/etc. is known
to have all ConstantData arguments, and drop the use-lists to
ref-counts in those cases. Callers need to check Value::hasUseList
before iterating through the use-list.
- Remove even the ref-counts. I'm not sure they have any benefit
besides minimizing the scope of this commit, and maintaining the
counts is not free.
Fixes#58629
Co-authored-by: Duncan P. N. Exon Smith <dexonsmith@apple.com>
Currently BlockAddresses store both the Function and the BasicBlock they
reference, and the BlockAddress is part of the use list of both the
Function and BasicBlock.
This is quite awkward, because this is not really a use of the function
itself (and walks of function uses generally skip block addresses for
that reason). This also has weird implications on function RAUW (as that
will replace the function in block addresses in a way that generally
doesn't make sense), and causes other peculiar issues, like the ability
to have multiple block addresses for one block (with different
functions).
Instead, I believe it makes more sense to specify only the basic block
and let the function be implied by the BB parent. This does mean that we
may have block addresses without a function (if the BB is not inserted),
but this should only happen during IR construction.
This patch adds support for LLVM IR atomicrmw `fmaximum` and `fminimum`
instructions.
These mirror the `llvm.maximum.*` and `llvm.minimum.*` instructions, but
are atomic and use IEEE754 2019 handling for NaNs, which is different to
`fmax` and `fmin`. See:
https://llvm.org/docs/LangRef.html#llvm-minimum-intrinsic
for more details.
Future changes will allow this LLVM IR to be lowered to specialised
assembler instructions on suitable targets, such as AArch64.
We currently accept label arguments to inline asm calls. This support
predates both blockaddresses and callbr and is only covered by one X86
test. Remove it in favor of callbr (or at least blockaddress, though
that cannot guarantee correct codegen, just like using block labels
directly can't).
I didn't bother implementing bitcode upgrade support for this, but I can
add it if desired.
This patch adds support for LLVM IR atomicrmw `fmaximum` and `fminimum`
instructions.
These mirror the `llvm.maximum.*` and `llvm.minimum.*` instructions, but
are atomic and use IEEE754 2019 handling for NaNs, which is different to
`fmax` and `fmin`. See:
https://llvm.org/docs/LangRef.html#llvm-minimum-intrinsic
for more details.
Future changes will allow this LLVM IR to be lowered to specialised
assembler instructions on suitable targets, such as AArch64.
See https://discourse.llvm.org/t/rfc-keep-globalvalue-guids-stable/84801
for context.
This is a non-functional change which just changes the interface of
GlobalValue, in preparation for future functional changes. This part
touches a fair few users, so is split out for ease of review. Future
changes to the GlobalValue implementation can then be focused purely on
that class.
This does the following:
* Rename GlobalValue::getGUID(StringRef) to
getGUIDAssumingExternalLinkage. This is simply making explicit at the
callsite what is currently implicit.
* Where possible, migrate users to directly calling getGUID on a
GlobalValue instance.
* Otherwise, where possible, have them call the newly renamed
getGUIDAssumingExternalLinkage, to make the assumption explicit.
There are a few cases where neither of the above are possible, as the
caller saves and reconstructs the necessary information to compute the
GUID themselves. We want to migrate these callers eventually, but for
this first step we leave them be.
The "preserve input debug-info format" flag allowed some tooling to opt
into not seeing the new debug records yet, and to not autoupgrade. This
was good at the time, but un-necessary now that we'll be ditching
intrinsics shortly.
It also hides errors now: verify-uselistorder was hardcoding this flag
to on, and as a result it hasn't seen debug records before. Thus, we
missed a uselistorder variation: constant-expressions such as GEPs can
be contained within debug records and completely isolated from the value
hierachy, see the metadata-use-uselistorder.ll test. These Values didn't
get ordered, but were legitimate uses of constants like "i64 0", and we
now run into difficulty handling that. The patch to AsmWriter seeks
Values to order even through debug-info now.
Finally there are a few intrinsics-tests relying on this flag that we
can just delete, such as one in llvm-reduce and another few in the
LocalTest unit tests. For the fast-isel test, it was added in
https://reviews.llvm.org/D67703 explicitly for checking the size of
blocks without debug-info and in 1525abb9c94 the codepath it tests moved
towards being sunsetted. It'll be totally redundant once RemoveDIs is on
permanently.
Note that there's now no explicit test for the textual-IR autoupgrade
path. I submit that we can rely on the thousands of .ll files where
we've only been bothered to update the outputs, not the inputs, to debug
records.
During the transition from debug intrinsics to debug records, we used
several different command line options to customise handling: the
printing of debug records to bitcode and textual could be independent of
how the debug-info was represented inside a module, whether the
autoupgrader ran could be customised. This was all valuable during
development, but now that totally removing debug intrinsics is coming
up, this patch removes those options in favour of a single flag
(experimental-debuginfo-iterators), which enables autoupgrade, in-memory
debug records, and debug record printing to bitcode and textual IR.
We need to do this ahead of removing the
experimental-debuginfo-iterators flag, to reduce the amount of
test-juggling that happens at that time.
There are quite a number of weird test behaviours related to this --
some of which I simply delete in this commit. Things like
print-non-instruction-debug-info.ll , the test suite now checks for
debug records in all tests, and we don't want to check we can print as
intrinsics. Or the update_test_checks tests -- these are duplicated with
write-experimental-debuginfo=false to ensure file writing for intrinsics
is correct, but that's something we're imminently going to delete.
A short survey of curious test changes:
* free-intrinsics.ll: we don't need to test that debug-info is a zero
cost intrinsic, because we won't be using intrinsics in the future.
* undef-dbg-val.ll: apparently we pinned this to non-RemoveDIs in-memory
mode while we sorted something out; it works now either way.
* salvage-cast-debug-info.ll: was testing intrinsics-in-memory get
salvaged, isn't necessary now
* localize-constexpr-debuginfo.ll: was producing "dead metadata"
intrinsics for optimised-out variable values, dbg-records takes the
(correct) representation of poison/undef as an operand. Looks like we
didn't update this in the past to avoid spurious test differences.
* Transforms/Scalarizer/dbginfo.ll: this test was explicitly testing
that debug-info affected codegen, and we deferred updating the tests
until now. This is just one of those silent gnochange issues that get
fixed by RemoveDIs.
Finally: I've added a bitcode test, dbg-intrinsics-autoupgrade.ll.bc,
that checks we can autoupgrade debug intrinsics that are in bitcode into
the new debug records.
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.
Before the patch,
`writeCombinedGlobalValueSummary` traversed entire
`cfiFunction*` for each module, just to pick a few
symbols from `DefOrUseGUIDs`.
Now we change internals of `cfiFunctionDefs` and
`cfiFunctionDecls` to maintain a map from GUID to StringSet.
So now we iterate `DefOrUseGUIDs`, usually small,
and pick exact subset of symbols.
Sorting is not strictly necessary, but it
preserves the order of emitted values.
The module currently stores the target triple as a string. This means
that any code that wants to actually use the triple first has to
instantiate a Triple, which is somewhat expensive. The change in #121652
caused a moderate compile-time regression due to this. While it would be
easy enough to work around, I think that architecturally, it makes more
sense to store the parsed Triple in the module, so that it can always be
directly queried.
For this change, I've opted not to add any magic conversions between
std::string and Triple for backwards-compatibilty purses, and instead
write out needed Triple()s or str()s explicitly. This is because I think
a decent number of them should be changed to work on Triple as well, to
avoid unnecessary conversions back and forth.
The only interesting part in this patch is that the default triple is
Triple("") instead of Triple() to preserve existing behavior. The former
defaults to using the ELF object format instead of unknown object
format. We should fix that as well.
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.
Model C/C++ `errno` macro by adding a corresponding `errno`
memory location kind to the IR. Preliminary work to separate
`errno` writes from other memory accesses, to the benefit of
alias analyses and optimization correctness.
Previous discussion: https://discourse.llvm.org/t/rfc-modelling-errno-memory-effects/82972.
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
4b3931c8ce/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 new AutoUpgrade function to convert some legacy nvvm.annotations
metadata to function level attributes. These attributes are quicker to
look-up so improve compile time and are more idiomatic than using
metadata which should not include required information that changes the
meaning of the program.
Currently supported annotations are:
- !"kernel" -> ptx_kernel calling convention
- !"align" -> alignstack parameter attributes (return not yet supported)
This PR removes the old `nocapture` attribute, replacing it with the new
`captures` attribute introduced in #116990. This change is
intended to be essentially NFC, replacing existing uses of `nocapture`
with `captures(none)` without adding any new analysis capabilities.
Making use of non-`none` values is left for a followup.
Some notes:
* `nocapture` will be upgraded to `captures(none)` by the bitcode
reader.
* `nocapture` will also be upgraded by the textual IR reader. This is to
make it easier to use old IR files and somewhat reduce the test churn in
this PR.
* Helper APIs like `doesNotCapture()` will check for `captures(none)`.
* MLIR import will convert `captures(none)` into an `llvm.nocapture`
attribute. The representation in the LLVM IR dialect should be updated
separately.
The ThinLTO index bitcode writer uses a helper forEachSummary to manage
preparation and writing of summaries needed for each distributed index
file. For alias summaries, it invokes the provided callback for the
aliasee as well, as we at least need to produce a value id for the
alias's summary. However, all summary generation for the aliasee itself
should be skipped on calls when IsAliasee is true. We invoke the
callback again if that value's summary is to be written as well.
We were asserting in debug mode when invoking collectMemProfCallStacks,
because a given stack id index was not in the StackIdIndicesToIndex
map. It was not added because the forEachSummary invocation that records
these ids in the map (invoked from the IndexBitcodeWriter constructor)
was correctly skipping this handling when invoked for aliasees. We need
the same guard in the invocation that calls collectMemProfCallStacks.
Note that this doesn't cause any real problems in a non-asserts build
as the missing map lookup will return the default 0 value from the map,
which isn't used since we don't actually write the corresponding
summary.
This introduces the `captures` attribute as described in:
https://discourse.llvm.org/t/rfc-improvements-to-capture-tracking/81420
This initial patch only introduces the IR/bitcode support for the
attribute and its in-memory representation as `CaptureInfo`. This will
be followed by a patch to upgrade and remove the `nocapture` attribute,
and then by actual inference/analysis support.
Based on the RFC feedback, I've used a syntax similar to the `memory`
attribute, though the only "location" that can be specified is `ret`.
I've added some pretty extensive documentation to LangRef on the
semantics. One non-obvious bit here is that using ptrtoint will not
result in a "return-only" capture, even if the ptrtoint result is only
used in the return value. Without this requirement we wouldn't be able
to continue ordinary capture analysis on the return value.
