8 Commits

Author SHA1 Message Date
Wang Pengcheng
3ac9fe69f7
[RISCV] CodeGen of RVE and ilp32e/lp64e ABIs (#76777)
This commit includes the necessary changes to clang and LLVM to support
codegen of `RVE` and the `ilp32e`/`lp64e` ABIs.

The differences between `RVE` and `RVI` are:
* `RVE` reduces the integer register count to 16(x0-x16).
* The ABI should be `ilp32e` for 32 bits and `lp64e` for 64 bits.

`RVE` can be combined with all current standard extensions.

The central changes in ilp32e/lp64e ABI, compared to ilp32/lp64 are:
* Only 6 integer argument registers (rather than 8).
* Only 2 callee-saved registers (rather than 12).
* A Stack Alignment of 32bits (rather than 128bits).
* ilp32e isn't compatible with D ISA extension.

If `ilp32e` or `lp64` is used with an ISA that has any of the registers
x16-x31 and f0-f31, then these registers are considered temporaries.

To be compatible with the implementation of ilp32e in GCC, we don't use
aligned registers to pass variadic arguments and set stack alignment\
to 4-bytes for types with length of 2*XLEN.

FastCC is also supported on RVE, while GHC isn't since there is only one
avaiable register.

Differential Revision: https://reviews.llvm.org/D70401
2024-01-16 20:44:30 +08:00
Vlad Serebrennikov
ae7b20b583 [clang][NFC] Refactor VectorType::VectorKind
This patch moves `VectorKind` to namespace scope, and make it complete at the point its bit-field is declared. It also converts it to a scoped enum.
2023-10-31 21:50:18 +03:00
Alex Bradbury
e3c57fdd84 [clang][RISCV] Fix bug in ABI handling of empty structs with hard FP calling conventions in C++
As reported in <https://github.com/llvm/llvm-project/issues/58929>,
Clang's handling of empty structs in the case of small structs that may
be eligible to be passed using the hard FP calling convention doesn't
match g++. In general, C++ record fields are never empty unless
[[no_unique_address]] is used, but the RISC-V FP ABI overrides this.

After this patch, fields of structs that contain empty records will be
ignored, even in C++, when considering eligibility for the FP calling
convention ('flattening'). It isn't explicitly noted in the RISC-V
psABI, but arrays of empty records will disqualify a struct for
consideration of using the FP calling convention in g++. This patch
matches that behaviour. The psABI issue
<https://github.com/riscv-non-isa/riscv-elf-psabi-doc/issues/358> seeks
to clarify this.

This patch was previously committed but reverted after a bug was found.
This recommit adds additional logic to prevent that bug (adding an extra
check for when a candidate from detectFPCCEligibleStructHelper may not
be valid).

Differential Revision: https://reviews.llvm.org/D142327
2023-08-07 10:45:22 +01:00
wangpc
edb5056300 [RISCV] Use correct LMUL!=1 types for __attribute__((riscv_rvv_vector_bits(N)))
We used to convert them to M1 types in arguments and return
value, which causes failures in CodeGen since it is not legal
to insert subvectors with LMUL>1 to M1 vectors.

Fixes 64266

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D156779
2023-08-02 01:21:14 +08:00
Alex Bradbury
0fa004e072 Revert "[clang][RISCV] Fix ABI handling of empty structs with hard FP calling conventions in C++"
This reverts commit 17a58b3ca7ec18585e9ea8ed8b39d72fe36fb6cb and the
minor documentation fix 569e99a471f618b7fdf045d5e96f21d3e3a7f898.

An issue was reported in https://reviews.llvm.org/D142327#inline-1510301
so reverting until it can be investigated and fixed.
2023-07-24 16:58:48 +01:00
Alex Bradbury
17a58b3ca7 [clang][RISCV] Fix ABI handling of empty structs with hard FP calling conventions in C++
As reported in <https://github.com/llvm/llvm-project/issues/58929>,
Clang's handling of empty structs in the case of small structs that may
be eligible to be passed using the hard FP calling convention doesn't
match g++. In general, C++ record fields are never empty unless
[[no_unique_address]] is used, but the RISC-V FP ABI overrides this.

After this patch, fields of structs that contain empty records will be
ignored, even in C++, when considering eligibility for the FP calling
convention ('flattening'). See also the relevant psABI issue
<https://github.com/riscv-non-isa/riscv-elf-psabi-doc/issues/358> which
seeks to clarify the documentation.

Fixes https://github.com/llvm/llvm-project/issues/58929

Differential Revision: https://reviews.llvm.org/D142327
2023-07-24 10:24:34 +01:00
Youngsuk Kim
6f986bffc5 [clang] Remove CGBuilderTy::CreateElementBitCast
`CGBuilderTy::CreateElementBitCast()` no longer does what its name suggests.

Remove remaining in-tree uses by one of the following methods.

* drop the call entirely
* fold it to an `Address` construction
* replace it with `Address::withElementType()`

This is a NFC cleanup effort.

Reviewed By: barannikov88, nikic, jrtc27

Differential Revision: https://reviews.llvm.org/D154285
2023-07-02 10:40:16 -04:00
Sergei Barannikov
992cb98462 [clang][CodeGen] Break up TargetInfo.cpp [8/8]
This commit breaks up CodeGen/TargetInfo.cpp into a set of *.cpp files,
one file per target. There are no functional changes, mostly just code moving.

Non-code-moving changes are:
* A virtual destructor has been added to DefaultABIInfo to pin the vtable to a cpp file.
* A few methods of ABIInfo and DefaultABIInfo were split into declaration + definition
  in order to reduce the number of transitive includes.
* Several functions that used to be static have been placed in clang::CodeGen
  namespace so that they can be accessed from other cpp files.

RFC: https://discourse.llvm.org/t/rfc-splitting-clangs-targetinfo-cpp/69883

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D148094
2023-06-17 07:14:50 +03:00