Separate libunwind into 1.3.2 and 1.5.0 builders, add a patch (#3856)

* Move libunwind files to a versioned subdirectory

The current version being built is 1.5.0, so the files now live in
`[email protected]`.

* Add libunwind PR 308 as a patch

L/LibUnwind/build_tarballs.jl → L/LibUnwind/LibUnwind@1.5.0/build_tarballs.jl

@@ -29,6 +29,7 @@ atomic_patch -p1 ${WORKSPACE}/srcdir/patches/libunwind-static-arm.patch
 atomic_patch -p0 ${WORKSPACE}/srcdir/patches/libunwind-configure-ppc64le.patch
 atomic_patch -p0 ${WORKSPACE}/srcdir/patches/libunwind-configure-static-lzma.patch
 atomic_patch -p1 ${WORKSPACE}/srcdir/patches/libunwind-cfa-rsp.patch
+atomic_patch -p1 ${WORKSPACE}/srcdir/patches/libunwind-dwarf-table.patch
 
 CFLAGS="${CFLAGS} -DPI -fPIC -I${prefix}/include"
 ./configure \

L/LibUnwind/LibUnwind@1.5.0/bundled/patches/libunwind-dwarf-table.patch

@@ -0,0 +1,36 @@
+From a5b5fd28ed03cb1ab524d24dc534c1fa167bf5a1 Mon Sep 17 00:00:00 2001
+From: Alex Arslan <[email protected]>
+Date: Fri, 5 Nov 2021 16:58:41 -0700
+Subject: [PATCH] Fix table indexing in `dwarf_search_unwind_table`
+
+`table_len` is used as an index into `table`, assuming it represents the
+number of entries. However, it is defined as the number of entries
+multiplied by `sizeof(unw_word_t)`. This is accounted for in other
+places that use `table_len`, e.g. in `lookup`, which divides out the
+size of `unw_word_t`, but the indexing expression uses `table_len`
+directly. So when `table` has say 2 entries, we're actually looking at
+index 15 rather than 1 in the comparison. This can cause the conditional
+to erroneously evaluate to true, allowing the following line to
+segfault.
+
+This was observed with JIT compiled code from Julia with LLVM on
+FreeBSD.
+
+Co-Authored-By: Jameson Nash <[email protected]>
+---
+ src/dwarf/Gfind_proc_info-lsb.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/src/dwarf/Gfind_proc_info-lsb.c b/src/dwarf/Gfind_proc_info-lsb.c
+index 5e27a501..af4cbce8 100644
+--- a/src/dwarf/Gfind_proc_info-lsb.c
++++ b/src/dwarf/Gfind_proc_info-lsb.c
+@@ -866,7 +866,7 @@ dwarf_search_unwind_table (unw_addr_space_t as, unw_word_t ip,
+   if (as == unw_local_addr_space)
+     {
+       e = lookup (table, table_len, ip - ip_base);
+-      if (e && &e[1] < &table[table_len])
++      if (e && &e[1] < &table[table_len / sizeof (unw_word_t)])
+ 	last_ip = e[1].start_ip_offset + ip_base;
+       else
+ 	last_ip = di->end_ip;