Let Propeller use specialized IDs for basic blocks, instead of MBB number.
This allows optimizations not just prior to asm-printer, but throughout the entire codegen.
This patch only implements the functionality under the new `LLVM_BB_ADDR_MAP` version, but the old version is still being used. A later patch will change the used version.
####Background
Today Propeller uses machine basic block (MBB) numbers, which already exist, to map native assembly to machine IR. This is done as follows.
- Basic block addresses are captured and dumped into the `LLVM_BB_ADDR_MAP` section just before the AsmPrinter pass which writes out object files. This ensures that we have a mapping that is close to assembly.
- Profiling mapping works by taking a virtual address of an instruction and looking up the `LLVM_BB_ADDR_MAP` section to find the MBB number it corresponds to.
- While this works well today, we need to do better when we scale Propeller to target other Machine IR optimizations like spill code optimization. Register allocation happens earlier in the Machine IR pipeline and we need an annotation mechanism that is valid at that point.
- The current scheme will not work in this scenario because the MBB number of a particular basic block is not fixed and changes over the course of codegen (via renumbering, adding, and removing the basic blocks).
- In other words, the volatile MBB numbers do not provide a one-to-one correspondence throughout the lifetime of Machine IR. Profile annotation using MBB numbers is restricted to a fixed point; only valid at the exact point where it was dumped.
- Further, the object file can only be dumped before AsmPrinter and cannot be dumped at an arbitrary point in the Machine IR pass pipeline. Hence, MBB numbers are not suitable and we need something else.
####Solution
We propose using fixed unique incremental MBB IDs for basic blocks instead of volatile MBB numbers. These IDs are assigned upon the creation of machine basic blocks. We modify `MachineFunction::CreateMachineBasicBlock` to assign the fixed ID to every newly created basic block. It assigns `MachineFunction::NextMBBID` to the MBB ID and then increments it, which ensures having unique IDs.
To ensure correct profile attribution, multiple equivalent compilations must generate the same Propeller IDs. This is guaranteed as long as the MachineFunction passes run in the same order. Since the `NextBBID` variable is scoped to `MachineFunction`, interleaving of codegen for different functions won't cause any inconsistencies.
The new encoding is generated under the new version number 2 and we keep backward-compatibility with older versions.
####Impact on Size of the `LLVM_BB_ADDR_MAP` Section
Emitting the Propeller ID results in a 23% increase in the size of the `LLVM_BB_ADDR_MAP` section for the clang binary.
Reviewed By: tmsriram
Differential Revision: https://reviews.llvm.org/D100808
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.
This is part of an effort to migrate from llvm::Optional to
std::optional:
https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
readelf --section-details displays ch_type/ch_size/ch_addralign for
a SHF_COMPRESSED section. Port the feature. There is a small difference
that readelf doesn't display `[<corrupt>]` for an empty section while
we do.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D136636
The current implementation outputs JSON in the following way:
[{'<filename>':{'FileSummary':{},...}}]
Using the filename as a key makes processing the JSON data awkward, and
should be avoided. This patch removes that outer key, since the
'FileSummary' data also includes a 'File' field, and so we lose no data.
Reviewed By: jhenderson, leonardchan
Differential Revision: https://reviews.llvm.org/D134843
The e_flags of existing object files are all 0x3 which happens to be
compatible. From this commit on, all LoongArch objects produced with
upstream LLVM will be of object file ABI v1, which is already supported
by binutils' master branch (to be released as 2.40), and is allowed by
the same binutils version to interlink with v0 objects so the existing
distributions have time to migrate.
Differential Revision: https://reviews.llvm.org/D134601
LLVM contains a helpful function for getting the size of a C-style
array: `llvm::array_lengthof`. This is useful prior to C++17, but not as
helpful for C++17 or later: `std::size` already has support for C-style
arrays.
Change call sites to use `std::size` instead.
Differential Revision: https://reviews.llvm.org/D133429
When there are no section headers section information printed by llvm-readelf is not useful and unnecessarily verbose. When there are no program headers there's a similar verbose output shown when section mapping is requested. Simplifying the message shown in these cases to match the behavior of `GNU binuntils readelf`.
Reviewed By: jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D130670
This patch drops the prefix `PT_RISCV_` when dumping `PT_RISCV_ATTRIBUTES`.
GNU readelf dumps it as `RISCV_ATTRIBUT`. Because GNU readelf uses
something like `%-14.14s` so only the first 14 bytes are printed.
Differential Revision: https://reviews.llvm.org/D128493
This is a resurrection of D106421 with the change that it keeps backward-compatibility. This means decoding the previous version of `LLVM_BB_ADDR_MAP` will work. This is required as the profile mapping tool is not released with LLVM (AutoFDO). As suggested by @jhenderson we rename the original section type value to `SHT_LLVM_BB_ADDR_MAP_V0` and assign a new value to the `SHT_LLVM_BB_ADDR_MAP` section type. The new encoding adds a version byte to each function entry to specify the encoding version for that function. This patch also adds a feature byte to be used with more flexibility in the future. An use-case example for the feature field is encoding multi-section functions more concisely using a different format.
Conceptually, the new encoding emits basic block offsets and sizes as label differences between each two consecutive basic block begin and end label. When decoding, offsets must be aggregated along with basic block sizes to calculate the final offsets of basic blocks relative to the function address.
This encoding uses smaller values compared to the existing one (offsets relative to function symbol).
Smaller values tend to occupy fewer bytes in ULEB128 encoding. As a result, we get about 17% total reduction in the size of the bb-address-map section (from about 11MB to 9MB for the clang PGO binary).
The extra two bytes (version and feature fields) incur a small 3% size overhead to the `LLVM_BB_ADDR_MAP` section size.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D121346
This is the first patch of a series to upstream support for the new
subtarget.
Contributors:
Jay Foad <jay.foad@amd.com>
Konstantin Zhuravlyov <kzhuravl_dev@outlook.com>
Patch 1/N for upstreaming AMDGPU gfx11 architectures.
Reviewed By: foad, kzhuravl, #amdgpu
Differential Revision: https://reviews.llvm.org/D124536
This ELF note is aarch64 and Android-specific. It specifies to the
dynamic loader that specific work should be scheduled to enable MTE
protection of stack and heap regions.
Current synthesis of the ".note.android.memtag" ELF note is done in the
Android build system. We'd like to move that to the compiler, and this
is the first step.
Reviewed By: MaskRay, jhenderson
Differential Revision: https://reviews.llvm.org/D119381
Instead of the GNU extension `SHF_GNU_RETAIN`, Solaris provides equivalent
functionality with `SHF_SUNW_NODISCARD`. This patch implements the necessary
support.
Tested on `sparcv9-sun-solaris2.11`, `amd64-pc-solaris2.11`, and
`x86_64-pc-linux-gnu`.
Differential Revision: https://reviews.llvm.org/D107955
Conceptually, the new encoding emits the offsets and sizes as label differences between each two consecutive basic block begin and end label. When decoding, the offsets must be aggregated along with basic block sizes to calculate the final relative-to-function offsets of basic blocks.
This encoding uses smaller values compared to the existing one (offsets relative to function symbol).
Smaller values tend to occupy fewer bytes in ULEB128 encoding. As a result, we get about 25% reduction
in the size of the bb-address-map section (reduction from about 9MB to 7MB).
Reviewed By: tmsriram, jhenderson
Differential Revision: https://reviews.llvm.org/D106421
This patch adds necessary definitions for LoongArch ELF files, including
relocation types. Also adds initial support to ELFYaml, llvm-objdump,
and llvm-readobj in order to work with LoongArch ELFs.
Differential revision: https://reviews.llvm.org/D115859
Summary:
Add code object v5 support (deafult is still v4)
Generate metadata for implicit kernel args for the new ABI
Set the metadata version to be 1.2
Reviewers:
t-tye, b-sumner, arsenm, and bcahoon
Fixes:
SWDEV-307188, SWDEV-307189
Differential Revision:
https://reviews.llvm.org/D118272
This reverts commit ef82063207.
- It conflicts with the existing llvm::size in STLExtras, which will now
never be called.
- Calling it without llvm:: breaks C++17 compat
A few header removal, some forward declarations. As usual, this can
break your build due to false dependencies, the most notable change are:
- "llvm/BinaryFormat/AMDGPUMetadataVerifier.h" no longer includes "llvm/BinaryFormat/MsgPackDocument.h"
The impact on generated preprocessed lines for LLVMBinaryFormat is
pretty nice:
$ clang++ -E -Iinclude -I../llvm/include ../llvm/lib/BinaryFormat/*.cpp -std=c++14 -fno-rtti -fno-exceptions | wc -l
before this patch: 705281
after this patch: 751456
Discourse thread on the topic: https://llvm.discourse.group/t/include-what-you-use-include-cleanup
LLVM Programmer’s Manual strongly discourages the use of `std::vector<bool>` and suggests `llvm::BitVector` as a possible replacement.
This patch does just that for llvm.
Reviewed By: dexonsmith
Differential Revision: https://reviews.llvm.org/D117121
Checking ELFType == ELF::ET_CORE first skips string comparison for the
majority of cases.
Suggested by Fangrui Song in D114635 for a similar construct.
Adds JSONScopedPrinter to llvm-readelf. It includes an empty
JSONELFDumper class which will be used to override any LLVMELFDumper
methods which utilize startLine() which JSONScopedPrinter cannot
provide.
This introduces a change where calls to llvm-readelf with non-ELF object
files that specify --elf-output-style=GNU will now print file summary
information where it previously didn't.
Fixes previous Windows test failure which occured due to JSON escaping
of '\' by not relying on LIT substitution.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D114225
Adds JSONScopedPrinter to llvm-readelf. It includes an empty
JSONELFDumper class which will be used to override any LLVMELFDumper
methods which utilize startLine() which JSONScopedPrinter cannot
provide.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D114225
Summary:
This is a NFC patch moving the GNUELFDumper<ELFT>::printEnum()
function from ELFDumper into ScopedPrinter.h for reuse.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D114840
The only binary-format-related field in the BBAddrMap structure is the function address (`Addr`), which will use uint64_t in 64B format and uint32_t in 32B format. This patch changes it to use uint64_t in both formats.
This allows non-templated use of the struct, at the expense of a marginal additional size overhead for the 32-bit format. The size of the BB address map section does not change.
Differential Revision: https://reviews.llvm.org/D112679
Notes generated in OpenBSD core files provide additional information
about the kernel state and CPU registers. These notes are described
in core.5, which can be viewed here: https://man.openbsd.org/core.5
Differential Revision: https://reviews.llvm.org/D111966
By default, such a non-template variable of non-volatile const-qualified type
having namespace-scope has internal linkage ([basic.link]), so no need for `static`.
The MSP430 ABI supports build attributes for specifying
the ISA, code model, data model and enum size in ELF object files.
Differential Revision: https://reviews.llvm.org/D107969
