chore: Update to LLVM 19

Latest Rust nightly switched to LLVM 19, so we need to update in order
to support rustc-llvm-proxy.

LLVM 19 packages don't provide shared libraries anymore, so the usafe
of `llvm-sys/force-dynamic` feature is dropped. Instead, we just let
llvm-sys decide what kind of libraries to use.

llvm-sys fails to build without libpolly being installed, which is not
right, but needs to be fixed upstream. For now, we just install it in CI.

Author: vadorovsky

.github/workflows/ci.yml

@@ -55,12 +55,9 @@ jobs:
         rust:
           - stable
           - beta
-          # TODO: unpin nightly. There was a regression in
-          # https://github.com/rust-lang/rust/compare/1cec373f6...becebb315 that causes
-          # tests/btf/assembly/anon_struct_c.rs to fail to link.
-          - nightly-2024-04-16
+          - nightly
         llvm:
-          - 18
+          - 19
           - source
     name: rustc=${{ matrix.rust }} llvm=${{ matrix.llvm }}
     needs: llvm
@@ -121,7 +118,10 @@ jobs:
           echo -e deb http://apt.llvm.org/jammy/ llvm-toolchain-jammy-${{ matrix.llvm }} main | sudo tee /etc/apt/sources.list.d/llvm.list
 
           sudo apt update
-          sudo apt -y install llvm-${{ matrix.llvm }}-dev
+          # TODO(vadorovsky): Remove the requirement of libpolly. It's being
+          # unnecessarily required by build.rs of llvm-sys, which does so based
+          # on the output of llvm-config.
+          sudo apt -y install llvm-${{ matrix.llvm }}-dev libpolly-${{ matrix.llvm }}-dev
           echo /usr/lib/llvm-${{ matrix.llvm }}/bin >> $GITHUB_PATH
 
       - name: Restore LLVM
@@ -152,14 +152,14 @@ jobs:
       - uses: taiki-e/install-action@cargo-hack
 
       - name: Check
-        run: cargo hack check --feature-powerset --features llvm-sys/force-dynamic
+        run: cargo hack check --feature-powerset
 
       - name: Build
-        run: cargo hack build --feature-powerset --features llvm-sys/force-dynamic
+        run: cargo hack build --feature-powerset
 
       - name: Test
         if: matrix.rust == 'nightly'
-        run: cargo hack test --feature-powerset --features llvm-sys/force-dynamic
+        run: cargo hack test --feature-powerset
 
       - uses: actions/checkout@v4
         if: matrix.rust == 'nightly'
@@ -170,7 +170,7 @@ jobs:
 
       - name: Install
         if: matrix.rust == 'nightly'
-        run: cargo install --path . --no-default-features --features llvm-sys/force-dynamic
+        run: cargo install --path . --no-default-features
 
       # TODO: Remove this and run the integration tests on the local machine when they pass on 5.15.
       - name: Download debian kernels

.github/workflows/llvm.yml

@@ -16,7 +16,7 @@ jobs:
       - id: ls-remote
         run: |
           set -euxo pipefail
-          value=$(git ls-remote https://github.com/aya-rs/llvm-project.git refs/heads/rustc/18.0-2024-02-13 | cut -f1)
+          value=$(git ls-remote https://github.com/aya-rs/llvm-project.git refs/heads/rustc/19.1-2024-07-30 | cut -f1)
           echo "sha=$value" >> "$GITHUB_OUTPUT"
 
       - id: cache-key

Cargo.lock

@@ -28,7 +28,7 @@ ar = { version = "0.9.0" }
 aya-rustc-llvm-proxy = { version = "0.9.2", optional = true }
 gimli = { version = "0.31.0" }
 libc = { version = "0.2.155" }
-llvm-sys = { features = ["disable-alltargets-init"], version = "180.0.0-rc2" }
+llvm-sys = { features = ["disable-alltargets-init"], version = "191.0.0-rc1" }
 log = { version = "0.4.22" }
 thiserror = { version = "1.0.63" }
 tracing = "0.1"

Cargo.toml

@@ -17,7 +17,7 @@ files with embedded bitcode (.o), optionally stored inside ar archives (.a).
 
 ## Installation
 
-The linker requires LLVM 18. It can use the same LLVM used by the rust compiler,
+The linker requires LLVM 19. It can use the same LLVM used by the rust compiler,
 or it can use an external LLVM installation.
 
 If your target is `aarch64-unknown-linux-gnu` (i.e. Linux on Apple Silicon) you 
@@ -33,14 +33,14 @@ cargo install bpf-linker
 
 ### Using external LLVM
 
-On Debian based distributions you need to install the `llvm-18-dev`, `libclang-18-dev`
-and `libpolly-18-dev` packages. If your distro doesn't have them you can get them
+On Debian based distributions you need to install the `llvm-19-dev`, `libclang-19-dev`
+and `libpolly-19-dev` packages. If your distro doesn't have them you can get them
 from the official LLVM repo at https://apt.llvm.org.
 
 On rpm based distribution you need the `llvm-devel` and `clang-devel` packages.
 If your distro doesn't have them you can get them from Fedora Rawhide.
 
-Once you have installed LLVM 18 you can install the linker running:
+Once you have installed LLVM 19 you can install the linker running:
 
 ```sh
 cargo install bpf-linker --no-default-features