macos: link libomp statically so the bundle stays one file (#42)

package_macos.sh rejects a binary that links anything outside /usr/lib and /System/Library, and Homebrew's libomp.dylib is exactly that, so `--target macos_app` failed on any Mac where CMake found OpenMP. ss_mac_prefer_static() (cmake/SsMacBundle.cmake) links the archive beside the dylib instead, the way MoltenVK is already static. libomp is keg-only, so build_develop.bash now passes -DOpenMP_ROOT at the keg: without it CMake finds no OpenMP and meshing, UV unwrap and metrics run serial with nothing said. Configure now reports either way.
2026-10-02 02:44:54 +08:00 · 2026-09-01 19:21:23 -04:00
parent 616f9b8512
commit 44635cbbea
5 changed files with 92 additions and 16 deletions
@@ -40,6 +40,25 @@ if command -v python3 >/dev/null 2>&1; then
    python3 tools/check_comment_length.py || exit 1
 fi

+# Homebrew's libomp is keg-only: nothing points at it, so CMake finds no
+# OpenMP and meshing, UV unwrap and metrics run serial (cmake/SsMacBundle.cmake
+# then has no dylib to make static either).
+if [ "$(uname)" = "Darwin" ]; then
+    case " $* " in
+        *" -DOpenMP_ROOT="*) ;;
+        *)
+            for omp_root in "$(brew --prefix libomp 2>/dev/null)" \
+                            /opt/homebrew/opt/libomp /usr/local/opt/libomp; do
+                [ -n "$omp_root" ] || continue
+                [ -f "$omp_root/lib/libomp.a" ] ||
+                    [ -f "$omp_root/lib/libomp.dylib" ] || continue
+                set -- "$@" "-DOpenMP_ROOT=$omp_root"
+                echo "OpenMP: passing -DOpenMP_ROOT=$omp_root (keg-only formula)"
+                break
+            done ;;
+    esac
+fi
+
 cmake -G Ninja -B build "$@" || exit $?

 # Repair the ninja dependency log.
@@ -13,6 +13,7 @@ message(STATUS "SS_BACKEND=vulkan: portable engine layer + "
 set(SS_BUILD_CLI ON)

 include(SsVulkan)
+include(SsMacBundle)
 ss_vulkan_lib()
 find_package(Threads REQUIRED)

@@ -35,7 +36,12 @@ target_link_libraries(csrc_portable PUBLIC ss_i18n)

 find_package(OpenMP)
 if(OpenMP_CXX_FOUND)
+    ss_mac_prefer_static(OpenMP::OpenMP_CXX
+        "`brew install libomp` ships the archive; \
+-DCMAKE_DISABLE_FIND_PACKAGE_OpenMP=ON drops OpenMP instead.")
    target_link_libraries(csrc_portable PUBLIC OpenMP::OpenMP_CXX)
+else()
+    message(STATUS "No OpenMP: meshing, UV unwrap and metrics run serial")
 endif()

 # ---------------------------------------------------------------------------
@@ -0,0 +1,40 @@
+# The macOS bundle carries one binary (docs/build.md#packaging), so nothing it
+# links may sit outside /usr/lib and /System/Library: a recorded /opt/homebrew
+# path runs only on the machine that built it. MoltenVK is static for that
+# reason (cmake/SsVulkan.cmake), tools/package_macos.sh rejects a bundle that
+# breaks the rule, and a dependency found as a dylib goes through here.
+
+# ss_mac_prefer_static(<imported target> [<hint>]) -- links the .a beside each
+# dylib in the target's link interface. Warns with <hint> and leaves the target
+# alone when an archive is missing; a no-op off macOS.
+function(ss_mac_prefer_static target)
+    if(NOT APPLE)
+        return()
+    endif()
+
+    get_target_property(_libs ${target} INTERFACE_LINK_LIBRARIES)
+    if(NOT _libs)
+        return()
+    endif()
+
+    set(_static "")
+    foreach(_lib IN LISTS _libs)
+        # Anything that is not an absolute dylib path -- a genex, a link flag,
+        # another target -- is not ours to rewrite.
+        if(NOT _lib MATCHES "\\.dylib$")
+            list(APPEND _static "${_lib}")
+            continue()
+        endif()
+        string(REGEX REPLACE "\\.dylib$" ".a" _archive "${_lib}")
+        if(NOT EXISTS "${_archive}")
+            message(WARNING "No ${_archive}, so ${target} keeps ${_lib}, which "
+                "packaging rejects (tools/package_macos.sh). ${ARGV1}")
+            return()
+        endif()
+        list(APPEND _static "${_archive}")
+    endforeach()
+
+    set_property(TARGET ${target} PROPERTY INTERFACE_LINK_LIBRARIES "${_static}")
+    list(JOIN _static " " _joined)
+    message(STATUS "${target}: ${_joined} linked statically")
+endfunction()
@@ -30,6 +30,7 @@ Always build through the dev scripts.
 | `SsEmbed.cmake` | `ss_embed_file()` — bake a file into a byte-array header |
 | `SsApps.cmake` | the `spirula` executable — every tool the build has, in one binary (backend-agnostic) |
 | `SsPackage.cmake` | the `macos_app` / `macos_dmg` targets ([Packaging](#packaging)) |
+| `SsMacBundle.cmake` | `ss_mac_prefer_static()` — the static linking a one-file bundle depends on ([Packaging](#packaging)) |
 | `SsChecks.cmake` | the source lints ([Lints](#lints)) — included last, so every target above depends on them |

 Exactly one backend module runs. It leaves behind `SS_WITH_TORCH` and
@@ -204,15 +205,19 @@ embedded into the binary. On an offline machine, transfer a matching `slangc`
 and point `-DSS_SLANGC=` at it.

 **macOS.** Vulkan backend only, through MoltenVK; `build_develop.bash` works
-as on Linux. Dependencies: `brew install cmake ninja`. Four things are
-macOS-only in the build: `cmake/SsVulkan.cmake` fetches a pinned universal
-MoltenVK and links it *statically* (`SS_MACOS_VULKAN=static`, the default) so
-the binary carries its own driver and copies to any Mac — the release tarball
-supplies the Vulkan headers too, so nothing comes from Homebrew;
-`cmake/SsSlang.cmake` pins a different Slang release (the one this project
-pins publishes no macOS assets); `build_develop.bash` reads free memory from
-`vm_stat` rather than `/proc`; and `ss_i18n` links CoreFoundation, which
-`i18n/Locale.cpp` asks for the user's locale.
+as on Linux. Dependencies: `brew install cmake ninja libomp`. The last is
+keg-only, so nothing finds it on its own — `build_develop.bash` passes
+`-DOpenMP_ROOT` at the keg, and a build without OpenMP runs meshing, UV unwrap
+and metrics serial. Five things are macOS-only in the build:
+`cmake/SsVulkan.cmake` fetches a pinned universal MoltenVK and links it
+*statically* (`SS_MACOS_VULKAN=static`, the default) so the binary carries its
+own driver and copies to any Mac — the release tarball supplies the Vulkan
+headers too, so nothing comes from Homebrew; `cmake/SsSlang.cmake` pins a
+different Slang release (the one this project pins publishes no macOS assets);
+`build_develop.bash` reads free memory from `vm_stat` rather than `/proc`;
+`ss_i18n` links CoreFoundation, which `i18n/Locale.cpp` asks for the user's
+locale; and `cmake/SsMacBundle.cmake` links the archive beside a dependency's
+dylib, which is what keeps the bundle one file ([Packaging](#packaging)).

 A static build has no loader, so it cannot load validation layers.
 `-DSS_MACOS_VULKAN=loader` links the installed loader instead (needs
@@ -297,10 +302,14 @@ taskbar. The banner carries no text — the product name and tagline are drawn
 over it by ImGui, so they stay translatable.

 The bundle carries **one binary**. That is only honest because a default
-macOS build links MoltenVK statically (`cmake/SsVulkan.cmake`), and the script
-checks rather than trusts it: `otool -L` output naming anything outside
+macOS build links MoltenVK statically (`cmake/SsVulkan.cmake`) and swaps every
+other dependency found as a dylib for the archive beside it
+(`ss_mac_prefer_static()` in `cmake/SsMacBundle.cmake` — libomp today), and the
+script checks rather than trusts it: `otool -L` output naming anything outside
 `/usr/lib` or `/System/Library` fails the packaging, since a bundle missing a
-dylib works on the build machine and nowhere else.
+dylib works on the build machine and nowhere else. Homebrew builds its archives
+for the host alone, so a bundle linking one is arm64-only and inherits that
+keg's minimum macOS version.

 Signing is ad-hoc (`--sign -`) by default. That is not optional decoration:
 Apple silicon kills an unsigned arm64 binary on exec, and copying the
@@ -5,9 +5,9 @@
 #   bash tools/package_macos.sh [--build-dir DIR] [--out DIR]
 #                               [--sign IDENTITY] [--dmg]
 #
-# The bundle carries one binary and its icon, which only works because a static
-# MoltenVK build links nothing outside the system frameworks
-# (cmake/SsVulkan.cmake) -- verified below, not assumed.
+# The bundle carries one binary and its icon, which only works because MoltenVK
+# and libomp are linked statically (cmake/SsVulkan.cmake,
+# cmake/SsMacBundle.cmake) -- verified below, not assumed.
 #
 # --sign defaults to ad-hoc ("-"): enough for a Mac the app is copied to
 # directly, not enough to survive the quarantine flag a download attaches.
@@ -121,7 +121,9 @@ STRAY=$(otool -L "$APP/Contents/MacOS/spirula" | tail -n +2 | awk '{print $1}' \
 if [ -n "$STRAY" ]; then
    echo "package_macos.sh: the binary links libraries this bundle does not carry:" >&2
    echo "$STRAY" | sed 's/^/    /' >&2
-    echo "  build with -DSS_MACOS_VULKAN=static (the default) to avoid it" >&2
+    echo "  such a bundle runs only on this machine. libvulkan: rebuild with" >&2
+    echo "  -DSS_MACOS_VULKAN=static (the default). Anything else: install its" >&2
+    echo "  .a so cmake/SsMacBundle.cmake links that (brew install libomp)." >&2
    exit 1
 fi