Implement fast unwinding using ghost unwind

.github/workflows/build.yml

@@ -47,7 +47,7 @@ jobs:
       - uses: actions/checkout@v6
       - name: Set up dependencies
         run: |
-          apk add --update build-base libunwind-dev lz4-dev musl-dev python3-dev python3-dbg gdb lldb git bash perl perl-datetime build-base perl-app-cpanminus
+          apk add --update build-base lz4-dev musl-dev python3-dev python3-dbg gdb lldb git bash perl perl-datetime build-base perl-app-cpanminus
           cpanm Date::Parse
           cpanm Capture::Tiny
           # Build elfutils
@@ -59,6 +59,14 @@ jobs:
           cd elfutils-$VERS
           CFLAGS='-Wno-error -DFNM_EXTMATCH=0 -g -O3' CXXFLAGS='-Wno-error -DFNM_EXTMATCH=0 -g -O3' ./configure --enable-libdebuginfod --disable-debuginfod --disable-nls --with-zstd
           make install
+          # Build libunwind from source
+          cd /
+          LIBUNWIND_VERS=1.8.3
+          curl -LO https://github.com/libunwind/libunwind/releases/download/v$LIBUNWIND_VERS/libunwind-$LIBUNWIND_VERS.tar.gz
+          tar xf libunwind-$LIBUNWIND_VERS.tar.gz
+          cd libunwind-$LIBUNWIND_VERS
+          ./configure --disable-minidebuginfo --prefix=/usr
+          make install
       - name: Create virtual environment
         run: |
           python3 -m venv /venv

.github/workflows/test_uv_python.yml

@@ -34,11 +34,22 @@ jobs:
           sudo apt-get install -qy \
             pkg-config \
             libdebuginfod-dev \
-            libunwind-dev \
             liblz4-dev \
             gdb \
             npm
 
+      - name: Build libunwind from source
+        run: |
+          cd /tmp
+          LIBUNWIND_VERS=1.8.3
+          curl -LO https://github.com/libunwind/libunwind/releases/download/v$LIBUNWIND_VERS/libunwind-$LIBUNWIND_VERS.tar.gz
+          tar xf libunwind-$LIBUNWIND_VERS.tar.gz
+          cd libunwind-$LIBUNWIND_VERS
+          ./configure --disable-minidebuginfo --prefix=/usr/local
+          make
+          sudo make install
+          sudo ldconfig
+
       - name: Install Python dependencies
         run: |
           uv pip install --upgrade pip cython pkgconfig

.gitignore

@@ -179,3 +179,6 @@ src/vendor/libbacktrace/install
 
 # pytest-textual-snapshot
 snapshot_report.html
+
+# Object files
+*.o

pyproject.toml

@@ -99,8 +99,14 @@ before-all = [
   "CFLAGS='-Wno-error -g -O3' CXXFLAGS='-Wno-error -g -O3' LDFLAGS=-lrt ./configure --enable-libdebuginfod --disable-debuginfod --disable-nls --with-zstd",
   "make install",
 
-  # Install Memray's other build and test dependencies
-  "yum install -y libunwind-devel",
+  # Build libunwind from source
+  "cd /",
+  "LIBUNWIND_VERS=1.8.3",
+  "/usr/bin/curl -LO https://github.com/libunwind/libunwind/releases/download/v$LIBUNWIND_VERS/libunwind-$LIBUNWIND_VERS.tar.gz",
+  "tar xf libunwind-$LIBUNWIND_VERS.tar.gz",
+  "cd libunwind-$LIBUNWIND_VERS",
+  "./configure --disable-minidebuginfo",
+  "make install",
 ]
 
 [tool.cibuildwheel.macos]
@@ -138,6 +144,9 @@ show_missing = true
 # Override the default linux before-all for musl linux
 [[tool.cibuildwheel.overrides]]
 select = "*-musllinux*"
+# Exclude libgcc_s from bundling - it contains _Unwind_* symbols and having
+# multiple copies (bundled + system) breaks C++ exception handling.
+repair-wheel-command = "auditwheel repair --exclude libgcc_s.so.1 -w {dest_dir} {wheel}"
 before-all = [
   # Remove gettext-dev, which conficts with the musl-libintl, which is a build
   # dependency of elfutils.
@@ -161,5 +170,14 @@ before-all = [
   "apk add libintl",
 
   # Install Memray's other build and test dependencies
-  "apk add --update libunwind-dev lz4-dev"
+  "apk add --update lz4-dev",
+
+  # Build libunwind from source
+  "cd /",
+  "LIBUNWIND_VERS=1.8.3",
+  "curl -LO https://github.com/libunwind/libunwind/releases/download/v$LIBUNWIND_VERS/libunwind-$LIBUNWIND_VERS.tar.gz",
+  "tar xf libunwind-$LIBUNWIND_VERS.tar.gz",
+  "cd libunwind-$LIBUNWIND_VERS",
+  "./configure --disable-minidebuginfo",
+  "make install",
 ]