Migrating all private STL code to the standard STL case but keeping it under the CPP namespace to avoid confusion. Starting with the type_traits header.
Differential Revision: https://reviews.llvm.org/D130727
This patch is a subpart of D125768 intented to make the review easier.
This patch introduces the same algorithms as in `libc/src/string/memory_utils/elements.h` but using the new API.
Differential Revision: https://reviews.llvm.org/D128335
This is a reland of D126773 / b2a9ea4420127d10b18ae648b16757665f8bbd7c.
The removal of `-mllvm -combiner-global-alias-analysis` has landed separately
in D128051 / 7b73f53790f3db9ee589dc26a05a481a5e9e6915.
And the removal of `-mllvm --tail-merge-threshold=0` is scheduled for
removal in a subsequent patch.
This patch is a subpart of D125768 intented to make the review easier.
The `SizedOp` struct represents operations to be performed on a certain number of bytes.
It is responsible for breaking them down into platform types and forwarded to the `Backend`.
The `Backend` struct represents a lower level abstraction that works only on types (`uint8_t`, `__m128i`, ...).
It is similar to instruction selection.
Differential Revision: https://reviews.llvm.org/D126768
This patch removes usage of `-mllvm -combiner-global-alias-analysis`
and relies on compiler builtin to implement `memcpy`.
Note that `-mllvm -combiner-global-alias-analysis` is actually only useful for
functions where buffers can alias (namely `memcpy` and `memmove`). The other
memory functions where not benefiting from the flag anyways.
The upside is that the memory functions can now be compiled from source with
thinlto (thinlto would not be able to carry on the flag when doing inlining).
The downside is that for compilers other than clang (i.e. not providing
`__builtin_memcpy_inline`) the codegen may be worse.
Differential Revision: https://reviews.llvm.org/D128051
Note, this is a re-submission of D125894 with `features = ["-header_modules"]`
added to the main BUILD.bazel file.
Some functions like `stpncpy` are implemented in terms of `memset` but are not
currently using `-fno-builtin-memset`. This is somewhat hidden by the fact that
we use `-ffreestanding` globally and that `-ffreestanding` implies
`-fno-builtin` for Clang.
This patch also removes `-mllvm -combiner-global-alias-analysis` that is Clang
specific and that does not bring substantial gains on modern processors.
Also we keep `-mllvm --tail-merge-threshold=0` for aarch64 in CMakeLists.txt
but we omit it in the Bazel config. This is because Bazel consumes the source
files directly and so it can use PGO to take optimal decisions locally.
Differential Revision: https://reviews.llvm.org/D126773
This patch is a subpart of D125768 intented to make the review easier.
The `Address` struct represents a pointer but also adds compile time knowledge
like alignment or temporal/non-temporal that helps with downstream instruction
selection.
Differential Revision: https://reviews.llvm.org/D125966
Some functions like `stpncpy` are implemented in terms of `memset` but are not
currently using `-fno-builtin-memset`. This is somewhat hidden by the fact that
we use `-ffreestanding` globally and that `-ffreestanding` implies
`-fno-builtin` for Clang.
This patch also removes `-mllvm -combiner-global-alias-analysis` that is Clang
specific and that does not bring substantial gains on modern processors.
Also we keep `-mllvm --tail-merge-threshold=0` for aarch64 in CMakeLists.txt
but we omit it in the Bazel config. This is because Bazel consumes the source
files directly and so it can use PGO to take optimal decisions locally.
Differential Revision: https://reviews.llvm.org/D125894
Previously, the entire support/CPP folder was in one header library,
which meant that a lot of headers were included where they shouldn't be.
This patch splits each header into its own target, as well as adjusting
each place they were included to only include what is used.
Reviewed By: sivachandra, lntue
Differential Revision: https://reviews.llvm.org/D121237
Although type punning is defined for union in C, it is UB in C++.
This patch introduces a bit_cast function to convert between types in a safe way.
This is necessary to get llvm-libc compile with GCC.
This patch is extracted from D119002.
Differential Revision: https://reviews.llvm.org/D119145
This implementation relies on storing data in registers for sizes up to 128B.
Then depending on whether `dst` is less (resp. greater) than `src` we move data forward (resp. backward) by chunks of 32B.
We first make sure one of the pointers is aligned to increase performance on large move sizes.
Differential Revision: https://reviews.llvm.org/D114637
previously, memcpy could get stuck in a loop, calling __builtin_memcpy
which would redirect to itself. This patch removes that path.
Reviewed By: gchatelet, sivachandra, lntue
Differential Revision: https://reviews.llvm.org/D115542
This patch applies the lint rules described in the previous patch. There
was also a significant amount of effort put into manually fixing things,
since all of the templated functions, or structs defined in /spec, were
not updated and had to be handled manually.
Reviewed By: sivachandra, lntue
Differential Revision: https://reviews.llvm.org/D114302
Up until now, all references to `errno` were marked with `NOLINT`, since
it was technically calling an external function. This fixes the lint
rules so that `errno`, as well as `malloc`, `calloc`, `realloc`, and
`free` are all allowed to be called as external functions. All of the
relevant `NOLINT` comments have been removed, and the documentation has
been updated.
Reviewed By: sivachandra, lntue, aaron.ballman
Differential Revision: https://reviews.llvm.org/D113946
This patch enables the benchmarking of `memmove`.
Ideally, this should be submitted before D114637.
Differential Revision: https://reviews.llvm.org/D114694
Adds an implementation for stpcpy and stpncpy, which are posix extension
functions.
Reviewed By: sivachandra, lntue
Differential Revision: https://reviews.llvm.org/D111913
This allows shipping individual functions without also having to provide
memset or bzero at the expense of bigger functions.
Similar to D113097.
Differential Revision: https://reviews.llvm.org/D113108
Similar to D113097 although not strictly necessary for now. It helps
keeping the same structure for all memory functions.
Differential Revision: https://reviews.llvm.org/D113103
This allows shipping individual functions without also having to provide
`memcpy` at the expense of bigger functions.
Next is to use this `inlined_memcpy` in:
- loader/linux/x86_64/start.cpp
- src/string/memmove.cpp
- src/string/mempcpy.cpp
- src/string/strcpy.cpp
- src/string/strdup.cpp
- src/string/strndup.cpp
Differential Revision: https://reviews.llvm.org/D113097
We may want to restrict the detected platforms to only `x86_64` and `aarch64`.
There are still custom detection in api.td but I don't think we can handle these:
- config/linux/api.td:205
- config/linux/api.td:199
Differential Revision: https://reviews.llvm.org/D112818
We may want to restrict the detected platforms to only `x86_64` and `aarch64`.
There are still custom detection in api.td but I don't think we can handle these:
- config/linux/api.td:205
- config/linux/api.td:199
Differential Revision: https://reviews.llvm.org/D112818
The idea is to move all pieces related to the actual libc sources to the
"src" directory. This allows downstream users to ship and build just the
"src" directory.
Reviewed By: michaelrj
Differential Revision: https://reviews.llvm.org/D112653
Add an implementation for memccpy and mempcpy. These functions are
posix extensions for the moment.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D111762
This adds strncat to llvm libc. In addition, an error was found with
strcat and that was fixed.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D111583
