Replace libunwind with framehop based library

Make.inc

@@ -1312,6 +1312,40 @@ else
 LIBLMDB := $(build_libdir)/liblmdb.a
 endif
 
+# framehop-backed unwinder (opt-in via USE_FRAMEHOP=1). When enabled on a supported
+# (os, arch), this defines JL_ENABLE_FRAMEHOP (so stackwalk.c routes the backtrace cursor
+# to framehop) and links the libframehopunwind built by deps/framehopunwind.mk. libunwind
+# stays linked (task.c context switching + proc-info still use it). The arch is further
+# gated by the JL_USE_FRAMEHOP predicate in julia_internal.h (x86_64/aarch64 only).
+# DO NOT MERGE: default USE_FRAMEHOP to 1 on supported platforms so every CI
+# pipeline exercises the framehop unwinder. Unsupported combinations keep 0 so
+# they don't trip the $(error) gates below; musl is skipped because
+# LibFramehopUnwind_jll has no *-linux-musl artifact yet.
+ifneq ($(filter $(OS),Linux FreeBSD Darwin),)
+ifneq ($(filter $(ARCH),x86_64 aarch64),)
+ifeq ($(DISABLE_LIBUNWIND), 0)
+ifeq (,$(findstring musl,$(shell $(CC) -dumpmachine 2>/dev/null)))
+USE_FRAMEHOP ?= 1
+endif
+endif
+endif
+endif
+USE_FRAMEHOP ?= 0
+FRAMEHOPUNWIND :=
+ifeq ($(USE_FRAMEHOP), 1)
+ifneq ($(DISABLE_LIBUNWIND), 0)
+$(error USE_FRAMEHOP=1 requires libunwind (framehop replaces only the backtrace cursor; task.c context switching still uses libunwind) — unset DISABLE_LIBUNWIND)
+endif
+ifeq ($(findstring $(OS),Linux FreeBSD Darwin),)
+$(error USE_FRAMEHOP=1 is not supported on OS=$(OS) (supported: Linux, FreeBSD, Darwin))
+endif
+ifeq ($(filter $(ARCH),x86_64 aarch64),)
+$(error USE_FRAMEHOP=1 is not supported on ARCH=$(ARCH) (supported: x86_64, aarch64))
+endif
+FRAMEHOPUNWIND := -lframehopunwind
+JCPPFLAGS += -DJL_ENABLE_FRAMEHOP
+endif
+
 ifeq ($(origin LLVM_CONFIG), undefined)
 ifeq ($(USE_SYSTEM_LLVM), 1)
 LLVM_CONFIG := llvm-config$(EXE)
@@ -1504,7 +1538,7 @@ CSL_NEXT_GLIBCXX_VERSION=GLIBCXX_3\.4\.35|GLIBCXX_3\.5\.|GLIBCXX_4\.
 # Note: we explicitly _do not_ define `CSL` here, since it requires some more
 # advanced techniques to decide whether it should be installed from a BB source
 # or not.  See `deps/csl.mk` for more detail.
-BB_PROJECTS := BLASTRAMPOLINE OPENBLAS LLVM LIBSUITESPARSE OPENLIBM GMP OPENSSL LIBSSH2 NGHTTP2 MPFR CURL LIBGIT2 PCRE LIBUV LIBUNWIND DSFMT OBJCONV ZLIB ZSTD P7ZIP LLD LIBTRACYCLIENT BOLT
+BB_PROJECTS := BLASTRAMPOLINE OPENBLAS LLVM LIBSUITESPARSE OPENLIBM GMP OPENSSL LIBSSH2 NGHTTP2 MPFR CURL LIBGIT2 PCRE LIBUV LIBUNWIND DSFMT OBJCONV ZLIB ZSTD P7ZIP LLD LIBTRACYCLIENT BOLT FRAMEHOPUNWIND
 
 define SET_BB_DEFAULT
 # First, check to see if BB is disabled on a global setting

Makefile

@@ -327,6 +327,10 @@ ifeq ($(WITH_TRACY),1)
 JL_PRIVATE_LIBS-0 += libTracyClient
 endif
 
+ifeq ($(USE_FRAMEHOP),1)
+# libjulia-internal and libjulia-codegen link against this.
+JL_PRIVATE_LIBS-0 += libframehopunwind
+endif
 
 ifeq ($(OS),Darwin)
 ifeq ($(USE_SYSTEM_BLAS),1)

contrib/refresh_checksums.mk

@@ -24,7 +24,7 @@ CLANG_TRIPLETS=$(filter %-darwin %-freebsd,$(TRIPLETS))
 NON_CLANG_TRIPLETS=$(filter-out %-darwin %-freebsd,$(TRIPLETS))
 
 # These are the projects currently using BinaryBuilder; both GCC-expanded and non-GCC-expanded:
-BB_PROJECTS=openssl libssh2 nghttp2 mpfr curl libgit2 pcre libuv unwind llvmunwind dsfmt objconv p7zip zlib zstd libsuitesparse openlibm blastrampoline libtracyclient mmtk_julia compilerrt
+BB_PROJECTS=openssl libssh2 nghttp2 mpfr curl libgit2 pcre libuv unwind llvmunwind dsfmt objconv p7zip zlib zstd libsuitesparse openlibm blastrampoline libtracyclient mmtk_julia compilerrt framehopunwind
 BB_GCC_EXPANDED_PROJECTS=openblas csl
 BB_CXX_EXPANDED_PROJECTS=gmp llvm clang llvm-tools lld
 # These are non-BB source-only deps

deps/Makefile

@@ -97,6 +97,12 @@ endif
 
 DEP_LIBS += cpufeatures
 
+# framehop-backed unwinder (opt-in via USE_FRAMEHOP=1; LibFramehopUnwind_jll by default,
+# source build with cargo via USE_BINARYBUILDER_FRAMEHOPUNWIND=0).
+ifeq ($(USE_FRAMEHOP), 1)
+DEP_LIBS += framehopunwind
+endif
+
 ifeq ($(USE_SYSTEM_LLVM), 0)
 DEP_LIBS += llvm
 endif
@@ -213,7 +219,7 @@ DEP_LIBS_STAGED_ALL := llvm llvm-tools clang llvmunwind unwind libuv pcre \
 	openlibm dsfmt blastrampoline openblas lapack gmp mpfr patchelf utf8proc \
 	objconv openssl libssh2 nghttp2 curl libgit2 libwhich zlib zstd lmdb p7zip csl \
 	sanitizers libsuitesparse lld libtracyclient ittapi nvtx \
-	terminfo cpufeatures
+	terminfo cpufeatures framehopunwind
 DEP_LIBS_ALL := $(DEP_LIBS_STAGED_ALL)
 
 ifneq ($(USE_BINARYBUILDER_OPENBLAS),0)
@@ -286,6 +292,7 @@ include $(SRCDIR)/gmp.mk
 include $(SRCDIR)/mpfr.mk
 include $(SRCDIR)/patchelf.mk
 include $(SRCDIR)/cpufeatures.mk
+include $(SRCDIR)/framehopunwind.mk
 include $(SRCDIR)/openssl.mk
 include $(SRCDIR)/libssh2.mk
 include $(SRCDIR)/nghttp2.mk

deps/checksums/framehopunwind

@@ -0,0 +1,14 @@
+LibFramehopUnwind.v0.1.2+0.aarch64-apple-darwin.tar.gz/md5/ca44618652f2a2037e081d0e0e901555
+LibFramehopUnwind.v0.1.2+0.aarch64-apple-darwin.tar.gz/sha512/f91a5e250c0fc6aec87839f07071e49d1d75733c820fc46e0dc78fcd0f31bb997f9be559e2bf07e978f866a151fb77030fc9c1323f564df12d3ed1e4987c904a
+LibFramehopUnwind.v0.1.2+0.aarch64-linux-gnu.tar.gz/md5/b04a9940cee25cba410e05d07bc3d369
+LibFramehopUnwind.v0.1.2+0.aarch64-linux-gnu.tar.gz/sha512/91cc159091fa7a967b790ae5885fa70148b4efae8be238d7e74ed96f2ea94c6da9ebb05fa23d5f0b2111e003b6f030f8f5d9882c3ba48c430c1cf158702c6dfe
+LibFramehopUnwind.v0.1.2+0.x86_64-apple-darwin.tar.gz/md5/21b4754af5503f32de51550b14c681c3
+LibFramehopUnwind.v0.1.2+0.x86_64-apple-darwin.tar.gz/sha512/929ebe9b82f9226558662028a5fcc8adc067339f202f1e6f4ab5b8f64c6a5d8661aa6ce7692688605ac4fda16ad8a8e4b3ada8fd03b24517591faedba8ca1970
+LibFramehopUnwind.v0.1.2+0.x86_64-linux-gnu.tar.gz/md5/617fe7b5deb83a5c2d496fd79ace49c2
+LibFramehopUnwind.v0.1.2+0.x86_64-linux-gnu.tar.gz/sha512/590459efaaffdbf19b1d2d6b8d98c6a7b088b86fef85ccb7fdbcaffe98f4f70865ab2e0422491b3d4255e2d863d465fe167b065bc3423ed4decac33ae2920552
+LibFramehopUnwind.v0.1.2+0.x86_64-unknown-freebsd.tar.gz/md5/7e5942d2d0cd0cdfdabc3e3df41ad29c
+LibFramehopUnwind.v0.1.2+0.x86_64-unknown-freebsd.tar.gz/sha512/85e646fee117834e1d35cf360a8ad14efeadc4a85981a2cddcc75ff26fabfbc46c2ac9d01b165f193c2c803c0d5c8d45bbee6d3607f4de95b49cfd758235e487
+LibFramehopUnwind.v0.1.2+0.x86_64-w64-mingw32.tar.gz/md5/51963cac6b098ddd0b96b97eaac4c54a
+LibFramehopUnwind.v0.1.2+0.x86_64-w64-mingw32.tar.gz/sha512/a0ce67e4472b4df8803c3a162bdac2eae50ccde2188c47f9e261c7da7b50892fdc6e6500b97032f30bcd8a0964f1436a8bfd937217ee4ddcf93c924ce8516113
+framehopunwind-745330dc336f4237cac36db79b5c9b6bc15c0232.tar.gz/md5/dd7ce5830b11aa9d1caca8fda8735b64
+framehopunwind-745330dc336f4237cac36db79b5c9b6bc15c0232.tar.gz/sha512/64a190d24ed7e899b4b2288f6b17ecd6f8483fa777416e21f06fd36de07a325c0a7fd20b478abe03f8e89c95cd0ceec78d6111723dbd2919978f353324551884

deps/framehopunwind.mk

@@ -0,0 +1,62 @@
+## FRAMEHOPUNWIND ##
+# framehop-backed, libunwind-compatible unwinder. Replaces libunwind's *backtrace* path.
+# Default: the prebuilt LibFramehopUnwind_jll artifact (bb-install). Source build
+# (USE_BINARYBUILDER_FRAMEHOPUNWIND=0) needs a Rust toolchain, like mmtk_julia.
+
+ifneq ($(USE_BINARYBUILDER_FRAMEHOPUNWIND),1)
+
+FRAMEHOPUNWIND_GIT_URL := https://github.com/gbaraldi/framehopunwind.git
+FRAMEHOPUNWIND_TAR_URL = https://api.github.com/repos/gbaraldi/framehopunwind/tarball/$1
+$(eval $(call git-external,framehopunwind,FRAMEHOPUNWIND,,,$(BUILDDIR)))
+
+FRAMEHOPUNWIND_BUILDDIR := $(BUILDDIR)/$(FRAMEHOPUNWIND_SRC_DIR)
+
+# Rust toolchain (override CARGO in Make.user if it is not on PATH).
+CARGO ?= cargo
+
+ifeq ($(USE_FRAMEHOP), 1)
+ifneq ($(XC_HOST),)
+$(error the framehopunwind source build does not support cross-compilation (cargo builds for the host triple); use USE_BINARYBUILDER_FRAMEHOPUNWIND=1)
+endif
+endif
+
+# NB: the first build fetches the crates.io deps (pinned via --locked); a fully-offline
+# build needs vendored crates or the jll. The `+` hands make's jobserver to cargo.
+$(FRAMEHOPUNWIND_BUILDDIR)/build-compiled: $(FRAMEHOPUNWIND_BUILDDIR)/source-extracted
+	@command -v $(CARGO) >/dev/null 2>&1 || { \
+		echo "ERROR: building framehopunwind from source requires a Rust toolchain (cargo >= 1.88)." >&2; \
+		echo "       Install one via https://rustup.rs, set CARGO in Make.user, or use" >&2; \
+		echo "       USE_BINARYBUILDER_FRAMEHOPUNWIND=1 for the prebuilt artifact." >&2; \
+		exit 1; }
+	+cd $(dir $<) && \
+		$(CARGO) build --release --locked --offline 2>/dev/null || \
+		$(CARGO) build --release --locked
+	echo 1 > $@
+
+define FRAMEHOPUNWIND_INSTALL
+	mkdir -p $2/$$(build_includedir)
+	mkdir -p $2/$$(build_shlibdir)
+	cp $1/include/framehopunwind.h $2/$$(build_includedir)/
+	cp $1/target/release/libframehopunwind.$$(SHLIB_EXT) $2/$$(build_shlibdir)/
+endef
+$(eval $(call staged-install, \
+	framehopunwind,$(FRAMEHOPUNWIND_SRC_DIR), \
+	FRAMEHOPUNWIND_INSTALL,,, \
+	$$(INSTALL_NAME_CMD)libframehopunwind.$$(SHLIB_EXT) $$(build_shlibdir)/libframehopunwind.$$(SHLIB_EXT)))
+
+clean-framehopunwind:
+	-rm -f $(FRAMEHOPUNWIND_BUILDDIR)/build-compiled
+	-rm -rf $(FRAMEHOPUNWIND_BUILDDIR)/target
+
+get-framehopunwind: $(FRAMEHOPUNWIND_SRC_FILE)
+extract-framehopunwind: $(FRAMEHOPUNWIND_BUILDDIR)/source-extracted
+configure-framehopunwind: extract-framehopunwind
+compile-framehopunwind: $(FRAMEHOPUNWIND_BUILDDIR)/build-compiled
+fastcheck-framehopunwind: check-framehopunwind
+check-framehopunwind: compile-framehopunwind
+
+else
+
+$(eval $(call bb-install,framehopunwind,FRAMEHOPUNWIND,false))
+
+endif # USE_BINARYBUILDER_FRAMEHOPUNWIND

deps/framehopunwind.version

@@ -0,0 +1,9 @@
+# -*- makefile -*-
+
+## jll artifact (JuliaBinaryWrappers/LibFramehopUnwind_jll.jl; built from the SHA1 below) ##
+FRAMEHOPUNWIND_JLL_NAME := LibFramehopUnwind
+FRAMEHOPUNWIND_JLL_VER := 0.1.2+0
+
+## source build ##
+FRAMEHOPUNWIND_BRANCH=main
+FRAMEHOPUNWIND_SHA1=745330dc336f4237cac36db79b5c9b6bc15c0232

src/Makefile

@@ -236,6 +236,14 @@ RT_LIBS := $(call whole_archive,$(LIBUV)) $(call whole_archive,$(LIBUTF8PROC)) $
 CG_LIBS := $(LIBUNWIND) $(CG_LLVMLINK) $(OSLIBS) $(LIBTRACYCLIENT) $(LIBITTAPI) $(LIBLMDB)
 endif
 
+# framehop-backed unwinder: link the deps-built libframehopunwind into both
+# libjulia-internal (stackwalk.c) and libjulia-codegen (debuginfo.cpp register_eh_frames),
+# which both call into framehop and so must share its single loaded instance. The header
+# is found via -I$(build_includedir) and the .so via COMMON_LIBPATHS. $(FRAMEHOPUNWIND) is
+# set by Make.inc (empty unless USE_FRAMEHOP=1 on a supported os/arch).
+RT_LIBS += $(FRAMEHOPUNWIND)
+CG_LIBS += $(FRAMEHOPUNWIND)
+
 ifeq ($(USEGCC),1)
 ifeq ($(USE_RT_STATIC_LIBGCC),1)
 RT_LIBS += -static-libgcc

src/debuginfo.cpp

@@ -1370,13 +1370,21 @@ void register_eh_frames(uint8_t *Addr, size_t Size)
   processFDEs((char*)Addr, Size, [](const char *Entry) JL_NOTSAFEPOINT {
       getJITDebugRegistry().libc_frames.libc_register_frame(Entry);
     });
+#ifdef JL_USE_FRAMEHOP
+  // Also register the JIT .eh_frame with framehop (the backtrace unwinder). The code
+  // range is derived from the FDEs; bytes are copied, so Addr may be freed later.
+  fh_register_jit_auto(Addr, Size);
+#endif
 }
 
 void deregister_eh_frames(uint8_t *Addr, size_t Size)
 {
    processFDEs((char*)Addr, Size, [](const char *Entry) JL_NOTSAFEPOINT {
       getJITDebugRegistry().libc_frames.libc_deregister_frame(Entry);
     });
+#ifdef JL_USE_FRAMEHOP
+  fh_deregister_jit_eh_frame(Addr);
+#endif
 }
 
 #elif (defined(_OS_LINUX_) || defined(_OS_FREEBSD_)) && \
@@ -1560,7 +1568,8 @@ static DW_EH_PE parseCIE(const uint8_t *Addr, const uint8_t *End) JL_NOTSAFEPOIN
 
 void register_eh_frames(uint8_t *Addr, size_t Size)
 {
-    // System unwinder
+    // System unwinder (used by C++ exception handling) — register regardless of which
+    // backtrace unwinder we use.
     jl_profile_atomic([&]() JL_NOTSAFEPOINT {
         __register_frame(Addr);
     });
@@ -1692,6 +1701,15 @@ void register_eh_frames(uint8_t *Addr, size_t Size)
     jl_profile_atomic([&]() JL_NOTSAFEPOINT {
         _U_dyn_register(di);
     });
+
+#ifdef JL_USE_FRAMEHOP
+    // Also register with framehop (the backtrace unwinder). [start_ip, end_ip) is the code
+    // range already computed above; the .eh_frame bytes are copied internally, so Julia may
+    // free its buffer after deregistration.
+    jl_profile_atomic([&]() JL_NOTSAFEPOINT {
+        fh_register_jit(Addr, Size, (uint64_t)start_ip, (uint64_t)end_ip);
+    });
+#endif
 }
 
 void deregister_eh_frames(uint8_t *Addr, size_t Size)
@@ -1702,6 +1720,12 @@ void deregister_eh_frames(uint8_t *Addr, size_t Size)
     // Deregistering with our unwinder (_U_dyn_cancel) requires a lookup table
     // to find the allocated entry above (or looking into libunwind's internal
     // data structures).
+#ifdef JL_USE_FRAMEHOP
+    // framehop keys JIT modules by .eh_frame address, so Addr is enough to deregister.
+    jl_profile_atomic([&]() JL_NOTSAFEPOINT {
+        fh_deregister_jit_eh_frame(Addr);
+    });
+#endif
 }
 
 #else

src/dlload.c

@@ -270,6 +270,11 @@ JL_NO_SANITIZE void *jl_dlopen(const char *filename, unsigned flags)
     struct link_map *map = (struct link_map*)hnd;
     if (filename && map)
       ForEachMappedRegion(map, __msan_unpoison);
+#endif
+#ifdef JL_USE_FRAMEHOP
+    // A newly-loaded object means new modules to unwind through; re-scan (off-signal).
+    if (hnd && !(flags & JL_RTLD_NOLOAD))
+        fh_modules_refresh();
 #endif
     return hnd;
 }
@@ -309,7 +314,13 @@ int jl_dlclose(void *handle)
         dlerror(); /* Reset error status. */
         return -1;
     }
-    return dlclose(handle);
+    int rc = dlclose(handle);
+#ifdef JL_USE_FRAMEHOP
+    // Mirror the jl_dlopen hook so unloaded ranges are not unwound with stale info.
+    if (rc == 0)
+        fh_modules_refresh();
+#endif
+    return rc;
 #endif
 }
 

src/init.c

@@ -778,6 +778,11 @@ JL_DLLEXPORT void jl_init_(jl_image_buf_t sysimage)
     jl_init_engine();
     jl_init_threading();
     jl_init_threadinginfra();
+#ifdef JL_USE_FRAMEHOP
+    // Bring up framehop before signal handlers are installed so early crashes get
+    // native backtraces. Idempotent; thread 0 registers in jl_init_threadtls below.
+    fh_init(0);
+#endif
     if (jl_options.handle_signals == JL_OPTIONS_HANDLE_SIGNALS_ON)
         jl_install_default_signal_handlers();
 

src/julia_internal.h

@@ -1557,6 +1557,16 @@ typedef struct {
     int inlined;
 } jl_frame_t;
 
+// framehop-backed unwinding (opt-in). The build defines JL_ENABLE_FRAMEHOP to turn this
+// on; JL_USE_FRAMEHOP is then derived for the (os, arch) combinations framehop supports.
+// When off, everything below is byte-for-byte the existing libunwind/dbghelp path.
+// Requires libunwind (the framehop path lives in the !JL_DISABLE_LIBUNWIND branch below).
+#if !defined(JL_USE_FRAMEHOP) && defined(JL_ENABLE_FRAMEHOP) && !defined(JL_DISABLE_LIBUNWIND)
+#  if (defined(_OS_LINUX_) || defined(_OS_FREEBSD_) || defined(_OS_DARWIN_)) && (defined(_CPU_X86_64_) || defined(_CPU_AARCH64_))
+#    define JL_USE_FRAMEHOP 1
+#  endif
+#endif
+
 #ifdef _OS_WINDOWS_
 #include <dbghelp.h>
 JL_DLLEXPORT EXCEPTION_DISPOSITION NTAPI __julia_personality(
@@ -1581,7 +1591,20 @@ void jl_profile_process_dll_events(void) JL_NOTSAFEPOINT;
 #  include <libunwind.h>
 #pragma GCC visibility pop
 typedef unw_context_t bt_context_t;
+// framehop integration is additive: libunwind stays linked (task.c context switching and
+// proc-info lookup still use it), but the *backtrace* cursor is framehop's. On
+// Linux/FreeBSD unw_context_t == ucontext_t, so jl_unw_init can extract framehop's
+// registers straight from a bt_context_t.
+#  ifdef JL_USE_FRAMEHOP
+// Default visibility so the fh_* references bind to the shared libframehopunwind
+// (Julia builds with -fvisibility=hidden; same treatment as libunwind.h above).
+#    pragma GCC visibility push(default)
+#    include "framehopunwind.h"
+#    pragma GCC visibility pop
+typedef fh_cursor bt_cursor_t;
+#  else
 typedef unw_cursor_t bt_cursor_t;
+#  endif
 #  if (!defined(SYSTEM_LIBUNWIND) || UNW_VERSION_MAJOR > 1 ||   \
        (UNW_VERSION_MAJOR == 1 && UNW_VERSION_MINOR != 0 && UNW_VERSION_MINOR != 1))
 // Enable our memory manager only for libunwind with our patch or
@@ -1598,9 +1621,29 @@ size_t rec_backtrace(jl_bt_element_t *bt_data, size_t maxsize, int skip) JL_NOTS
 // which was asynchronously interrupted.
 size_t rec_backtrace_ctx(jl_bt_element_t *bt_data, size_t maxsize, bt_context_t *ctx,
                          jl_gcframe_t *pgcstack) JL_NOTSAFEPOINT;
-#ifdef LLVMLIBUNWIND
+// The macOS profiler's compact-unwind-fault DWARF retry; libunwind-only (framehop
+// recovers faults via safe_restore instead, see signals-mach.c).
+#if defined(LLVMLIBUNWIND) && !defined(JL_USE_FRAMEHOP)
 size_t rec_backtrace_ctx_dwarf(jl_bt_element_t *bt_data, size_t maxsize, bt_context_t *ctx, jl_gcframe_t *pgcstack) JL_NOTSAFEPOINT;
 #endif
+// rec_backtrace_ctx for a context belonging to another (suspended) thread or a
+// not-currently-running task; under framehop the target supplies exact stack bounds,
+// elsewhere the extra arguments are ignored.
+#ifdef JL_USE_FRAMEHOP
+size_t rec_backtrace_ctx_target(jl_bt_element_t *bt_data, size_t maxsize, bt_context_t *ctx,
+                                jl_gcframe_t *pgcstack, jl_ptls_t target_ptls,
+                                jl_task_t *target_task) JL_NOTSAFEPOINT;
+#else
+STATIC_INLINE size_t rec_backtrace_ctx_target(jl_bt_element_t *bt_data, size_t maxsize,
+                                              bt_context_t *ctx, jl_gcframe_t *pgcstack,
+                                              jl_ptls_t target_ptls,
+                                              jl_task_t *target_task) JL_NOTSAFEPOINT
+{
+    (void)target_ptls;
+    (void)target_task;
+    return rec_backtrace_ctx(bt_data, maxsize, ctx, pgcstack);
+}
+#endif
 JL_DLLEXPORT jl_value_t *jl_get_backtrace(void) JL_CANSAFEPOINT;
 JL_DLLEXPORT jl_value_t *jl_backtrace_from_here(int returnsp, int skip) JL_CANSAFEPOINT;
 void jl_fprint_critical_error(ios_t *t, int sig, int si_code, bt_context_t *context, jl_task_t *ct) JL_CANSAFEPOINT;