As noted in 3e8355df84, this seems to be
unproblematic. If we keep this disabled, it is unfortunately not
possible to do PGO with the default clang stdenv on GNU platforms.
Clang assumes that `libLTO.dylib` is located at `../lib` in the same
prefix as `clang`, but that’s not true in nixpkgs. `libLTO.dylib` is
actually located at `libllvm^lib/lib.libLTO.dylib`.
The nixpkgs-unstable channel's programs.sqlite was used to identify
packages producing exactly one binary, and these automatically added
to their package definitions wherever possible.
Before the change `llvmPackages.bintools.bintools.targetPrefix` was not
present. This exposed as a discrepansy between `binutils` and `llvm`:
`binutils`:
nix-repl> stdenv.cc.bintools.bintools.targetPrefix
""
nix-repl> stdenv.cc.bintools.targetPrefix
""
`llvm`:
nix-repl> pkgsLLVM.stdenv.cc.bintools.targetPrefix
"x86_64-unknown-linux-gnu-"
nix-repl> pkgsLLVM.stdenv.cc.bintools.bintools.targetPrefix
error:
error: attribute 'targetPrefix' missing
As a result some attributes like `pkgsLLVM.actionlint` failed to
evaluate:
$ nix build --no-link -f. pkgsLLVM.actionlint
...
error: attribute 'targetPrefix' missing
at pkgs/development/compilers/ghc/9.4.8.nix:232:46:
231| export READELF="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}readelf"
232| export STRIP="${bintoolsFor.strip}/bin/${bintoolsFor.strip.targetPrefix}strip"
| ^
The change exposes binary prefix the same way as `binutils` does.
It appears that LLVM's build system no longer sets the executable's
rpath to include the faux resource root we pass in, so we need to make
sure cc-wrapper does this.
found with fdupes
```
pkgs/development/compilers/llvm/8/clang/purity.patch
pkgs/development/compilers/llvm/5/clang/purity.patch
pkgs/development/compilers/llvm/6/clang/purity.patch
pkgs/development/compilers/llvm/7/clang/purity.patch
```
found with fdupes
```
pkgs/development/compilers/llvm/8/libcxxabi/no-threads.patch
pkgs/development/compilers/llvm/10/libcxxabi/no-threads.patch
pkgs/development/compilers/llvm/9/libcxxabi/no-threads.patch
pkgs/development/compilers/llvm/11/libcxxabi/no-threads.patch
```
compiler-rt has accumulated several regressions that prevent it from building
on ARMv6. It is important to note that there are two major versions of ARMv6:
base ARMv6 and ARMv6K. ARMv6K includes several important new instructions,
such as non-word size atomic operations (ldrexd, strexd, etc.) and the yield
instruction. Most ARMv6 CPUs actually implement ARMv6K, including all those used
in Raspberry Pis, but nixpkgs' "raspberryPi" platform targets base ARMv6.
compiler-rt versions 8-14 fail to build on ARMv6 and ARMv6K. compiler-rt 15 (not
yet in nixpkgs) builds on ARMv6K but not ARMv6. This patch fixes versions 9-14
on both ARMv6 variants. The patches don't apply cleanly to version 8, and I
figured it wasn't worth carrying another version of the patches for such an old
version.
A total of five patches are required to get compiler-rt building on ARMv6:
* armv6-mcr-dmb.patch: use `mcr` to provide the equivalent of `dmb` on ARMv6.
Included in LLVM 15.
* armv6-sync-ops-no-thumb.patch: prevent certain atomic operation functions
from using Thumb mode. Included in LLVM 15.
* armv6-no-ldrexd-strexd.patch: don't use ldrexd or strexd, which are not
available in base ARMv6. Submitted upstream by me.
* armv6-scudo-no-yield.patch: use nop instead of yield on ARMv6 in standalone
scudo. Required by versions >=13, since they enable standalone scudo.
Submitted upstream by me.
* armv6-scudo-libatomic.patch: link standlone scudo to libatomic on ARMv6 (and
any other platforms that need it). Not yet submitted because the backport is
a bit different from the upstream version and I need to test it.
The missing xcrun meant builtins were missing from darwin. This
apparently wasn't an issue until now, but is in projects using
`@available` checks. (The ARM64 hack was apparently the previous
solution to fixing broken SDK detection.)
linux-headers-5.13 removed <cyclades.h> along with device support.
Backport a single https://reviews.llvm.org/D102059 upstream change to
fix compiler-rt build.
Use local patches as there is a whitespace change compared to upstream.
