OCaml stack switching

.github/workflows/build.yml

@@ -14,70 +14,31 @@ jobs:
           - '5.2.0+ox'
 
     runs-on: ${{ matrix.os }}
+    container:
+      image: alpine:latest
     steps:
+      # This has to come first because the `actions/*` GitHub Actions require `node`,
+      # which isn't installed by default on this container image.
+      - name: "Install apk packages"
+        run: |
+          apk add autoconf bash bubblewrap build-base clang coreutils git libstdc++ \
+            libstdc++-dev libunwind-static linux-headers lld llvm20 llvm20-dev llvm20-static \
+            nodejs opam rsync upx zlib-static zstd-static
+          echo "PATH=/usr/lib/llvm20/bin:$PATH" >> "$GITHUB_ENV"
+
       - name: Checkout code
         uses: actions/checkout@v6
 
+      # This is necessary to avoid an error of the form 'fatal: detected dubious ownership in repository ...'
+      - run: git config --global --add safe.directory $(pwd)
+
       - uses: actions/cache@v5
         with:
           path: ~/.opam
-          key: ${{ matrix.os }}-opam-${{ matrix.ocaml-version }}-1
-
-      - name: Install musl-compatible kernel headers
-        run: |
-          mkdir musl-kernel
-          filename='v4.19.88-1.tar.gz'
-          wget "https://github.com/sabotage-linux/kernel-headers/archive/refs/tags/$filename"
-          shasum --check <(echo "44a07e9f18033cff7840dbb112fff2862c0fb8fc  $filename")
-          tar -xzf "$filename" -C musl-kernel --strip-components=1
-          echo "C_INCLUDE_PATH=$(pwd)/musl-kernel/x86/include" >> "$GITHUB_ENV"
-          echo "CC=musl-gcc" >> "$GITHUB_ENV"
-
-      - name: "Install apt packages"
-        run: |
-          sudo apt-get update
-          sudo apt-get install -y bubblewrap musl musl-tools libucl1 rsync
-
-      - name: Install upx
-        run: |
-          # The version that comes with focal is broken for musl binaries, so we have to download
-          # from another location.
-          filename='upx-ucl_3.96-2_amd64.deb'
-          wget "http://ftp.debian.org/debian/pool/main/u/upx-ucl/$filename"
-          shasum --check <(echo "0b3c901a6ae8db264a0e58aad9bbed4ef3e925b9  $filename")
-          sudo dpkg -i upx-ucl_3.96-2_amd64.deb
-
-      - name: Build zlib with musl
-        run: |
-          mkdir musl-zlib
-          filename='zlib-1.3.2.tar.gz'
-          wget "https://zlib.net/$filename"
-          shasum -a 256 --check <(echo "bb329a0a2cd0274d05519d61c667c062e06990d72e125ee2dfa8de64f0119d16  $filename")
-          tar -xzf "$filename" -C musl-zlib --strip-components=1
-          cd musl-zlib
-          CC=musl-gcc ./configure --libdir=/usr/lib/x86_64-linux-musl --includedir=/usr/include/x86_64-linux-musl
-          make -j$(nproc)
-          sudo make install
-
-      - name: Build zstd with musl
-        run: |
-          mkdir musl-zstd
-          filename='zstd-1.5.5.tar.gz'
-          wget "https://github.com/facebook/zstd/releases/download/v1.5.5/$filename"
-          shasum --check <(echo "4479ecc74300d23391d99fbebf2fddd47aed9b28  $filename")
-          tar -xzf "$filename" -C musl-zstd --strip-components=1
-          cd musl-zstd
-          CC=musl-gcc make -j$(nproc)
-          sudo make INCLUDEDIR=/usr/include/x86_64-linux-musl LIBDIR=/usr/lib/x86_64-linux-musl install
+          key: ${{ matrix.os }}-opam-${{ matrix.ocaml-version }}-2
 
       - name: Use OCaml ${{ matrix.ocaml-version }}
         run: |
-          filename='opam-2.5.0-x86_64-linux'
-          wget "https://github.com/ocaml/opam/releases/download/2.5.0/$filename"
-          shasum --check <(echo "67fb680a785f0bc7ceb57155f21786c0680ef5fe  $filename")
-          sudo mv "$filename" /usr/local/bin/opam
-          sudo chmod a+x /usr/local/bin/opam
-
           export OPAMYES=1
           export OPAMJOBS=$(($(nproc) + 2))
           echo "OPAMYES=1" >> "$GITHUB_ENV"
@@ -93,11 +54,12 @@ jobs:
 
       - run: opam exec -- make PROFILE=static
 
-      - run: opam exec -- dune runtest
+      - run: opam exec -- dune runtest --profile=static
 
       - name: Compress magic-trace executable
         run: |
           cp _build/install/default/bin/magic-trace .
+          chmod u+w magic-trace
           ls -l magic-trace
           strip magic-trace
           upx -9 magic-trace

.gitignore

@@ -2,5 +2,11 @@ _build
 *.install
 *.merlin
 _opam
+perf.data
+perf.data.old
 .vscode/*
 !.vscode/tasks.json
+*.fxt
+*.fxt.old
+*.fxt.gz
+*.fxt.gz.old

.ocamlformat

@@ -1 +1,3 @@
 profile=janestreet
+wrap-comments=false
+parse-docstrings=false

direct_backend/cinaps/dune

@@ -1,5 +1,6 @@
 (library
  (name magic_trace_lib_cinaps_helpers)
+ (no_dynlink)
  (libraries core)
  (preprocess
   (pps ppx_jane)))

dune

@@ -1,6 +1,8 @@
 (env
  (static
   (flags
-   (:standard -cclib -static))))
+   (:standard -cclib -static -cclib -no-pie))
+  (link_flags
+   (:standard -cclib -static -cclib -no-pie))))
 
 (vendored_dirs vendor)

dune-project

@@ -1 +1 @@
-(lang dune 2.0)
+(lang dune 3.0)

lib/magic_trace/src/dune

@@ -1,6 +1,7 @@
 (library
  (name magic_trace)
  (public_name magic-trace.magic_trace)
+ (no_dynlink)
  (foreign_stubs
   (language c)
   (names stop_stubs))

lib/magic_trace/test/dune

@@ -1,5 +1,6 @@
 (library
  (name magic_trace_test)
+ (no_dynlink)
  (libraries core expect_test_helpers_core magic_trace)
  (preprocess
   (pps ppx_jane)))

magic-trace.opam

@@ -27,6 +27,7 @@ depends: [
   "owee"         {>= "0.8"}
   "re"           {>= "1.8.0"}
   "zstandard"
+  "vec"
 ]
 synopsis: "Collects and displays high-resolution traces of what a process is doing"
 description: "https://github.com/janestreet/magic-trace"