This is a major change on how we represent nested name qualifications in
the AST.
* The nested name specifier itself and how it's stored is changed. The
prefixes for types are handled within the type hierarchy, which makes
canonicalization for them super cheap, no memory allocation required.
Also translating a type into nested name specifier form becomes a no-op.
An identifier is stored as a DependentNameType. The nested name
specifier gains a lightweight handle class, to be used instead of
passing around pointers, which is similar to what is implemented for
TemplateName. There is still one free bit available, and this handle can
be used within a PointerUnion and PointerIntPair, which should keep
bit-packing aficionados happy.
* The ElaboratedType node is removed, all type nodes in which it could
previously apply to can now store the elaborated keyword and name
qualifier, tail allocating when present.
* TagTypes can now point to the exact declaration found when producing
these, as opposed to the previous situation of there only existing one
TagType per entity. This increases the amount of type sugar retained,
and can have several applications, for example in tracking module
ownership, and other tools which care about source file origins, such as
IWYU. These TagTypes are lazily allocated, in order to limit the
increase in AST size.
This patch offers a great performance benefit.
It greatly improves compilation time for
[stdexec](https://github.com/NVIDIA/stdexec). For one datapoint, for
`test_on2.cpp` in that project, which is the slowest compiling test,
this patch improves `-c` compilation time by about 7.2%, with the
`-fsyntax-only` improvement being at ~12%.
This has great results on compile-time-tracker as well:

This patch also further enables other optimziations in the future, and
will reduce the performance impact of template specialization resugaring
when that lands.
It has some other miscelaneous drive-by fixes.
About the review: Yes the patch is huge, sorry about that. Part of the
reason is that I started by the nested name specifier part, before the
ElaboratedType part, but that had a huge performance downside, as
ElaboratedType is a big performance hog. I didn't have the steam to go
back and change the patch after the fact.
There is also a lot of internal API changes, and it made sense to remove
ElaboratedType in one go, versus removing it from one type at a time, as
that would present much more churn to the users. Also, the nested name
specifier having a different API avoids missing changes related to how
prefixes work now, which could make existing code compile but not work.
How to review: The important changes are all in
`clang/include/clang/AST` and `clang/lib/AST`, with also important
changes in `clang/lib/Sema/TreeTransform.h`.
The rest and bulk of the changes are mostly consequences of the changes
in API.
PS: TagType::getDecl is renamed to `getOriginalDecl` in this patch, just
for easier to rebasing. I plan to rename it back after this lands.
Fixes#136624
Fixes https://github.com/llvm/llvm-project/issues/43179
Fixes https://github.com/llvm/llvm-project/issues/68670
Fixes https://github.com/llvm/llvm-project/issues/92757
When calculating the layout for a cbuffer field, if that field is a
ConstantArrayType, desguar it before casting it to a ConstantArrayType.
Closes#134668
---------
Co-authored-by: Eli Friedman <efriedma@quicinc.com>
fixes https://github.com/llvm/llvm-project/issues/133199
As of the third commit the fix to the linker missing references in
`Targets/DirectX.cpp` found in
https://github.com/llvm/llvm-project/pull/133776 was fixed by moving
`HLSLBufferLayoutBuilder.cpp` to `clang/lib/CodeGen/Targets/`.
It fixes the circular reference issue found in
https://github.com/llvm/llvm-project/pull/133619 for all
`-DBUILD_SHARED_LIBS=ON` builds by removing `target_link_libraries` from
the sub directory cmake files.
testing for amdgpu offload was done via
`cmake -B ../llvm_amdgpu -S llvm -GNinja -C
offload/cmake/caches/Offload.cmake -DCMAKE_BUILD_TYPE=Release`
PR https://github.com/llvm/llvm-project/pull/132252 Created a second
file that shared <TargetName>.cpp in clang/lib/CodeGen/CMakeLists.txt
For example There were two AMDGPU.cpp's one in TargetBuiltins and the
other in Targets. Even though these were in different directories
libtool warns that it might not distinguish them because they share the
same base name.
There are two potential fixes. The easy fix is to rename one of them and
keep one cmake file. That solution though doesn't future proof this
problem in the event of a third <TargetName>.cpp and it seems teams want
to just use the target name
https://github.com/llvm/llvm-project/pull/132252#issuecomment-2758178483.
The alternative fix that this PR went with is to seperate the cmake
files into their own sub directories as static libs.
Processes `HLSLResourceBindingAttr` attributes that represent
`register(c#)` annotations on default constant buffer declarations and
applies its value to the buffer layout. Any default buffer declarations
without an explicit `register(c#)` annotation are placed after the
elements with explicit layout.
This PR also adds a test case for a `cbuffer` that does not have
`packoffset` on all declarations. Same layout rules apply here as well.
Fixes#126791
Translates `cbuffer` declaration blocks to `target("dx.CBuffer")` type. Creates global variables in `hlsl_constant` address space for all `cbuffer` constant and adds metadata describing which global constant belongs to which constant buffer. For explicit constant buffer layout information an explicit layout type `target("dx.Layout")` is used. This might change in the future.
The constant globals are temporary and will be removed in upcoming pass that will translate `load` instructions in the `hlsl_constant` address space to constant buffer load intrinsics calls off a CBV handle (#124630, #112992).
See [Constant buffer design
doc](https://github.com/llvm/wg-hlsl/pull/94) for more details.
Fixes#113514, #106596