diff --git a/Makefile b/Makefile
index 9e9f2c8f0c900..533c8b7e2989d 100644
--- a/Makefile
+++ b/Makefile
@@ -477,7 +477,7 @@ endif
 
 exe:
 	# run Inno Setup to compile installer
-	$(call spawn,$(JULIAHOME)/dist-extras/inno/iscc.exe /DAppVersion=$(JULIA_VERSION) /DSourceDir="$(call cygpath_w,$(BUILDROOT)/julia-$(JULIA_COMMIT))" /DRepoDir="$(call cygpath_w,$(JULIAHOME))" /F"$(JULIA_BINARYDIST_FILENAME)" /O"$(call cygpath_w,$(BUILDROOT))" $(call cygpath_w,$(JULIAHOME)/contrib/windows/build-installer.iss))
+	$(call spawn,$(JULIAHOME)/dist-extras/inno/iscc.exe /DAppVersion=$(JULIA_VERSION) /DSourceDir="$(call cygpath_w,$(BUILDROOT)/julia-$(JULIA_COMMIT))" /DRepoDir="$(call cygpath_w,$(JULIAHOME))" /F"$(JULIA_BINARYDIST_FILENAME)" /O"$(call cygpath_w,$(BUILDROOT))" $(INNO_ARGS) $(call cygpath_w,$(JULIAHOME)/contrib/windows/build-installer.iss))
 	chmod a+x "$(BUILDROOT)/$(JULIA_BINARYDIST_FILENAME).exe"
 
 app:
diff --git a/base/compiler/tfuncs.jl b/base/compiler/tfuncs.jl
index 15fb81e6643ed..18dec7d839950 100644
--- a/base/compiler/tfuncs.jl
+++ b/base/compiler/tfuncs.jl
@@ -770,7 +770,7 @@ function getfield_tfunc(@nospecialize(s00), @nospecialize(name))
                 nv = fieldindex(widenconst(s), nv, false)
             end
             if isa(nv, Int) && 1 <= nv <= length(s.fields)
-                return s.fields[nv]
+                return unwrapva(s.fields[nv])
             end
         end
         s = widenconst(s)
diff --git a/base/compiler/typeutils.jl b/base/compiler/typeutils.jl
index d6eb7305b1c8d..ebb06a33a2d74 100644
--- a/base/compiler/typeutils.jl
+++ b/base/compiler/typeutils.jl
@@ -70,15 +70,6 @@ function typesubtract(@nospecialize(a), @nospecialize(b))
     if isa(a, Union)
         return Union{typesubtract(a.a, b),
                      typesubtract(a.b, b)}
-    elseif a isa DataType
-        if b isa DataType
-            if a.name === b.name === Tuple.name && length(a.types) == length(b.types)
-                ta = switchtupleunion(a)
-                if length(ta) > 1
-                    return typesubtract(Union{ta...}, b)
-                end
-            end
-        end
     end
     return a # TODO: improve this bound?
 end
diff --git a/base/file.jl b/base/file.jl
index 66640a20a39a7..c8db25cabc9bd 100644
--- a/base/file.jl
+++ b/base/file.jl
@@ -458,6 +458,32 @@ function tempdir()
     end
 end
 
+"""
+    prepare_for_deletion(path::AbstractString)
+
+Prepares the given `path` for deletion by ensuring that all directories within that
+`path` have write permissions, so that files can be removed from them.  This is
+automatically invoked by methods such as `mktempdir()` to ensure that no matter what
+weird permissions a user may have created directories with within the temporary prefix,
+it will always be deleted.
+"""
+function prepare_for_deletion(path::AbstractString)
+    # Nothing to do for non-directories
+    if !isdir(path)
+        return
+    end
+
+    try chmod(path, filemode(path) | 0o333)
+    catch; end
+    for (root, dirs, files) in walkdir(path)
+        for dir in dirs
+            dpath = joinpath(root, dir)
+            try chmod(dpath, filemode(dpath) | 0o333)
+            catch; end
+        end
+    end
+end
+
 const TEMP_CLEANUP_MIN = Ref(1024)
 const TEMP_CLEANUP_MAX = Ref(1024)
 const TEMP_CLEANUP = Dict{String,Bool}()
@@ -484,6 +510,7 @@ function temp_cleanup_purge(all::Bool=true)
             if (all || asap) && ispath(path)
                 need_gc && GC.gc(true)
                 need_gc = false
+                prepare_for_deletion(path)
                 rm(path, recursive=true, force=true)
             end
             !ispath(path) && delete!(TEMP_CLEANUP, path)
@@ -682,7 +709,10 @@ function mktempdir(fn::Function, parent::AbstractString=tempdir();
         fn(tmpdir)
     finally
         try
-            ispath(tmpdir) && rm(tmpdir, recursive=true)
+            if ispath(tmpdir)
+                prepare_for_deletion(tmpdir)
+                rm(tmpdir, recursive=true)
+            end
         catch ex
             @error "mktempdir cleanup" _group=:file exception=(ex, catch_backtrace())
             # might be possible to remove later
diff --git a/base/methodshow.jl b/base/methodshow.jl
index 6f9c46f929100..1e4b68efb0f66 100644
--- a/base/methodshow.jl
+++ b/base/methodshow.jl
@@ -13,7 +13,7 @@ function argtype_decl(env, n, sig::DataType, i::Int, nargs, isva::Bool) # -> (ar
     s = string(n)
     i = findfirst(isequal('#'), s)
     if i !== nothing
-        s = s[1:i-1]
+        s = s[1:prevind(s, i)]
     end
     if t === Any && !isempty(s)
         return s, ""
diff --git a/base/process.jl b/base/process.jl
index e664d7411de69..e578db43d3732 100644
--- a/base/process.jl
+++ b/base/process.jl
@@ -546,7 +546,7 @@ Returns successfully if the process has already exited, but throws an
 error if killing the process failed for other reasons (e.g. insufficient
 permissions).
 """
-function kill(p::Process, signum::Integer)
+function kill(p::Process, signum::Integer=SIGTERM)
     iolock_begin()
     if process_running(p)
         @assert p.handle != C_NULL
@@ -558,9 +558,8 @@ function kill(p::Process, signum::Integer)
     iolock_end()
     nothing
 end
-kill(ps::Vector{Process}) = foreach(kill, ps)
-kill(ps::ProcessChain) = foreach(kill, ps.processes)
-kill(p::Process) = kill(p, SIGTERM)
+kill(ps::Vector{Process}, signum::Integer=SIGTERM) = for p in ps; kill(p, signum); end
+kill(ps::ProcessChain, signum::Integer=SIGTERM) = kill(ps.processes, signum)
 
 """
     getpid(process) -> Int32
diff --git a/contrib/windows/build-installer.iss b/contrib/windows/build-installer.iss
index 4e38276d0a038..63eca3e4b56f4 100644
--- a/contrib/windows/build-installer.iss
+++ b/contrib/windows/build-installer.iss
@@ -74,6 +74,9 @@ UninstallDisplayName={#AppNameLong}
 UninstallDisplayIcon={app}\{#AppMainExeName}
 UninstallFilesDir={app}\uninstall
 
+#ifdef Sign
+SignTool=mysigntool
+#endif
 
 [Languages]
 Name: "english"; MessagesFile: "compiler:Default.isl"
diff --git a/deps/Versions.make b/deps/Versions.make
index be2303484ba7c..f9e474f287f34 100644
--- a/deps/Versions.make
+++ b/deps/Versions.make
@@ -30,7 +30,7 @@ CURL_BB_REL = 1
 LIBGIT2_VER = 0.28.2
 LIBGIT2_BB_REL = 1
 LIBUV_VER = 1.29.1
-LIBUV_BB_REL = 0
+LIBUV_BB_REL = 9
 OBJCONV_VER = 2.49.0
 OBJCONV_BB_REL = 0
 ZLIB_VER = 1.2.11
diff --git a/deps/checksums/LibUV.v2.0.0-9.aarch64-linux-gnu.tar.gz/md5 b/deps/checksums/LibUV.v2.0.0-9.aarch64-linux-gnu.tar.gz/md5
new file mode 100644
index 0000000000000..2955de37e027f
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.aarch64-linux-gnu.tar.gz/md5
@@ -0,0 +1 @@
+2bd32030f78a45b6195999407f510aa5
diff --git a/deps/checksums/LibUV.v2.0.0-9.aarch64-linux-gnu.tar.gz/sha512 b/deps/checksums/LibUV.v2.0.0-9.aarch64-linux-gnu.tar.gz/sha512
new file mode 100644
index 0000000000000..bef5e4d5d86a6
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.aarch64-linux-gnu.tar.gz/sha512
@@ -0,0 +1 @@
+1ccc3ffa4f5473e74f4ce342423bddc268a6f70d9743aa2f11124163db27f3e56711e85555895e2ff506a025f9dfbfec686ff457e949aa45d86ffef5ec6c2037
diff --git a/deps/checksums/LibUV.v2.0.0-9.aarch64-linux-musl.tar.gz/md5 b/deps/checksums/LibUV.v2.0.0-9.aarch64-linux-musl.tar.gz/md5
new file mode 100644
index 0000000000000..d7a9dce808eac
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.aarch64-linux-musl.tar.gz/md5
@@ -0,0 +1 @@
+c3b6f24843c4be53fa72d995a9296450
diff --git a/deps/checksums/LibUV.v2.0.0-9.aarch64-linux-musl.tar.gz/sha512 b/deps/checksums/LibUV.v2.0.0-9.aarch64-linux-musl.tar.gz/sha512
new file mode 100644
index 0000000000000..713eb1f2f7812
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.aarch64-linux-musl.tar.gz/sha512
@@ -0,0 +1 @@
+1659c0fa80c162411c284bcf85dfac2d6a699bf2b09bbfe7868ebade0c5e424e3bda416b345cc101f946dbbbd7fea677318d733ad12bf3bb6ba5555accbe8d45
diff --git a/deps/checksums/LibUV.v2.0.0-9.armv7l-linux-gnueabihf.tar.gz/md5 b/deps/checksums/LibUV.v2.0.0-9.armv7l-linux-gnueabihf.tar.gz/md5
new file mode 100644
index 0000000000000..de164951f7fa3
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.armv7l-linux-gnueabihf.tar.gz/md5
@@ -0,0 +1 @@
+71b09d3e80394d283756348854a65017
diff --git a/deps/checksums/LibUV.v2.0.0-9.armv7l-linux-gnueabihf.tar.gz/sha512 b/deps/checksums/LibUV.v2.0.0-9.armv7l-linux-gnueabihf.tar.gz/sha512
new file mode 100644
index 0000000000000..71ca326cc3196
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.armv7l-linux-gnueabihf.tar.gz/sha512
@@ -0,0 +1 @@
+b360975c81b574a9ed673c106ab0a520eac42e594b48933a9e0526a1e00462da524b86a516d860945e04fe395ddba31acebe1ed8609aa65ccc7eea784ef0fb68
diff --git a/deps/checksums/LibUV.v2.0.0-9.armv7l-linux-musleabihf.tar.gz/md5 b/deps/checksums/LibUV.v2.0.0-9.armv7l-linux-musleabihf.tar.gz/md5
new file mode 100644
index 0000000000000..4c68299162b86
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.armv7l-linux-musleabihf.tar.gz/md5
@@ -0,0 +1 @@
+40bf3062a91d1c24122e71be0479ed94
diff --git a/deps/checksums/LibUV.v2.0.0-9.armv7l-linux-musleabihf.tar.gz/sha512 b/deps/checksums/LibUV.v2.0.0-9.armv7l-linux-musleabihf.tar.gz/sha512
new file mode 100644
index 0000000000000..3da89c2a0c7ee
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.armv7l-linux-musleabihf.tar.gz/sha512
@@ -0,0 +1 @@
+aa66897bd05f13daf682104b16329093f1234922c07d97e8134db0a1f499d17c8716704e4c8b21a00d148afa920f4fa1d2fd884a545c973b8a6734d7aada5fc6
diff --git a/deps/checksums/LibUV.v2.0.0-9.i686-linux-gnu.tar.gz/md5 b/deps/checksums/LibUV.v2.0.0-9.i686-linux-gnu.tar.gz/md5
new file mode 100644
index 0000000000000..b176f993aa66f
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.i686-linux-gnu.tar.gz/md5
@@ -0,0 +1 @@
+11477f56cffc636d48245ad623eea1c7
diff --git a/deps/checksums/LibUV.v2.0.0-9.i686-linux-gnu.tar.gz/sha512 b/deps/checksums/LibUV.v2.0.0-9.i686-linux-gnu.tar.gz/sha512
new file mode 100644
index 0000000000000..54542c43f6e91
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.i686-linux-gnu.tar.gz/sha512
@@ -0,0 +1 @@
+da82d92db2ba2bf0c0b52928390bbf0ee5a8212883fd23a772c7735c7f427ca229229b75e8d7ff8964d42a2ab0614f1adfd156e0ef067b682931e0236fe7ef7b
diff --git a/deps/checksums/LibUV.v2.0.0-9.i686-linux-musl.tar.gz/md5 b/deps/checksums/LibUV.v2.0.0-9.i686-linux-musl.tar.gz/md5
new file mode 100644
index 0000000000000..609ecb4e59ebd
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.i686-linux-musl.tar.gz/md5
@@ -0,0 +1 @@
+739be10627a93a419f0a9f193232931c
diff --git a/deps/checksums/LibUV.v2.0.0-9.i686-linux-musl.tar.gz/sha512 b/deps/checksums/LibUV.v2.0.0-9.i686-linux-musl.tar.gz/sha512
new file mode 100644
index 0000000000000..c49cb60652102
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.i686-linux-musl.tar.gz/sha512
@@ -0,0 +1 @@
+8abf48cf61ef7dd1a7d619bb062ba919d97d9d68f2e3d04dd7c4fdfacf01e5bcc864ecd6fe5e8782ba72822764883583d60c5164c96fe030a979d3436278f2bd
diff --git a/deps/checksums/LibUV.v2.0.0-9.i686-w64-mingw32.tar.gz/md5 b/deps/checksums/LibUV.v2.0.0-9.i686-w64-mingw32.tar.gz/md5
new file mode 100644
index 0000000000000..d0603d4804576
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.i686-w64-mingw32.tar.gz/md5
@@ -0,0 +1 @@
+3e27de72945d3eda858798b8faaaa2f9
diff --git a/deps/checksums/LibUV.v2.0.0-9.i686-w64-mingw32.tar.gz/sha512 b/deps/checksums/LibUV.v2.0.0-9.i686-w64-mingw32.tar.gz/sha512
new file mode 100644
index 0000000000000..47c2c429b9634
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.i686-w64-mingw32.tar.gz/sha512
@@ -0,0 +1 @@
+c0dd0c3dea0f9e2b7319f46733685a5ac1ecb6423886e669aeb14e1bc8aae4017ad994b8802dcc9f57cceaebf138f3f4328b97d2f0a64c317243ce3fe282dd52
diff --git a/deps/checksums/LibUV.v2.0.0-9.powerpc64le-linux-gnu.tar.gz/md5 b/deps/checksums/LibUV.v2.0.0-9.powerpc64le-linux-gnu.tar.gz/md5
new file mode 100644
index 0000000000000..e6a0484d73886
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.powerpc64le-linux-gnu.tar.gz/md5
@@ -0,0 +1 @@
+4231a4b2c1adb333f2ed603ad22b92c5
diff --git a/deps/checksums/LibUV.v2.0.0-9.powerpc64le-linux-gnu.tar.gz/sha512 b/deps/checksums/LibUV.v2.0.0-9.powerpc64le-linux-gnu.tar.gz/sha512
new file mode 100644
index 0000000000000..47c6e2b165c24
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.powerpc64le-linux-gnu.tar.gz/sha512
@@ -0,0 +1 @@
+aef5f19dc6b1061f1ebd205e4663779498e0094435dc875e4ebca3dda67b0c11d5cb8eb88a20f9baaf82d59a1e83a5fedcdb7a6be9255d738aca1981656523bf
diff --git a/deps/checksums/LibUV.v2.0.0-9.x86_64-apple-darwin14.tar.gz/md5 b/deps/checksums/LibUV.v2.0.0-9.x86_64-apple-darwin14.tar.gz/md5
new file mode 100644
index 0000000000000..949a55c685a58
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.x86_64-apple-darwin14.tar.gz/md5
@@ -0,0 +1 @@
+ac719bf85a3619e9d238d0efb1291ef0
diff --git a/deps/checksums/LibUV.v2.0.0-9.x86_64-apple-darwin14.tar.gz/sha512 b/deps/checksums/LibUV.v2.0.0-9.x86_64-apple-darwin14.tar.gz/sha512
new file mode 100644
index 0000000000000..59b8e810d7aca
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.x86_64-apple-darwin14.tar.gz/sha512
@@ -0,0 +1 @@
+753e640aeca665b6e35deed35860d8e3f3076b9c1cfae382d029827e138bc3ff65a90bbee2f828a8371ac15bca29469c1720b3c1b9c29f56d8b402790c7608e8
diff --git a/deps/checksums/LibUV.v2.0.0-9.x86_64-linux-gnu.tar.gz/md5 b/deps/checksums/LibUV.v2.0.0-9.x86_64-linux-gnu.tar.gz/md5
new file mode 100644
index 0000000000000..a86d696b18338
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.x86_64-linux-gnu.tar.gz/md5
@@ -0,0 +1 @@
+446e2ffac64e64b24c47d17d03cdc3a3
diff --git a/deps/checksums/LibUV.v2.0.0-9.x86_64-linux-gnu.tar.gz/sha512 b/deps/checksums/LibUV.v2.0.0-9.x86_64-linux-gnu.tar.gz/sha512
new file mode 100644
index 0000000000000..aebd451c8e4d4
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.x86_64-linux-gnu.tar.gz/sha512
@@ -0,0 +1 @@
+185ec913e17aa00b866c1c7f2b4645c80ab8ff067ee1c176cc33c75e6161450994a795feeb46ca0bcbb80bbc727de8a4532ddee5b658fdc9bbf10b1676a54026
diff --git a/deps/checksums/LibUV.v2.0.0-9.x86_64-linux-musl.tar.gz/md5 b/deps/checksums/LibUV.v2.0.0-9.x86_64-linux-musl.tar.gz/md5
new file mode 100644
index 0000000000000..2c40c1f925383
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.x86_64-linux-musl.tar.gz/md5
@@ -0,0 +1 @@
+0f7913302512ad1002ce77b2c619a4c8
diff --git a/deps/checksums/LibUV.v2.0.0-9.x86_64-linux-musl.tar.gz/sha512 b/deps/checksums/LibUV.v2.0.0-9.x86_64-linux-musl.tar.gz/sha512
new file mode 100644
index 0000000000000..95213b7850a17
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.x86_64-linux-musl.tar.gz/sha512
@@ -0,0 +1 @@
+c8cc6d5a27bc21f28a1cb7e75b40947e9870ace136e50040fefe067c30398f3a1655ce28fa43b28e09ff743d5f1bbce061dff2f47ab67ca81cd3d1e6f360317a
diff --git a/deps/checksums/LibUV.v2.0.0-9.x86_64-unknown-freebsd11.1.tar.gz/md5 b/deps/checksums/LibUV.v2.0.0-9.x86_64-unknown-freebsd11.1.tar.gz/md5
new file mode 100644
index 0000000000000..20a55c8a252c3
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.x86_64-unknown-freebsd11.1.tar.gz/md5
@@ -0,0 +1 @@
+2fd4a5b814194d588186485b8cc5b73d
diff --git a/deps/checksums/LibUV.v2.0.0-9.x86_64-unknown-freebsd11.1.tar.gz/sha512 b/deps/checksums/LibUV.v2.0.0-9.x86_64-unknown-freebsd11.1.tar.gz/sha512
new file mode 100644
index 0000000000000..900f3d55128b7
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.x86_64-unknown-freebsd11.1.tar.gz/sha512
@@ -0,0 +1 @@
+4b72488b5afa6dcc64763155489a4aad0f438266bdc039c03ed8835cf14f6159c5151751cdbc61cdfb54253bf458b2af4a7d3d8cb6ad70ffb154df0082c2149b
diff --git a/deps/checksums/LibUV.v2.0.0-9.x86_64-w64-mingw32.tar.gz/md5 b/deps/checksums/LibUV.v2.0.0-9.x86_64-w64-mingw32.tar.gz/md5
new file mode 100644
index 0000000000000..aec56e6f81632
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.x86_64-w64-mingw32.tar.gz/md5
@@ -0,0 +1 @@
+bab85c5eae8370f4058e06b6779c7dc7
diff --git a/deps/checksums/LibUV.v2.0.0-9.x86_64-w64-mingw32.tar.gz/sha512 b/deps/checksums/LibUV.v2.0.0-9.x86_64-w64-mingw32.tar.gz/sha512
new file mode 100644
index 0000000000000..9ba2115db44b0
--- /dev/null
+++ b/deps/checksums/LibUV.v2.0.0-9.x86_64-w64-mingw32.tar.gz/sha512
@@ -0,0 +1 @@
+78f42e12f99a9dddfec221c03e43fb76ac0ab664b6aec7f3f1a5f55fbc72c9cf03e2e7f99a4bb22b9a0e568cd448d52f5b91f22cf4aff6a3a3e5ddc6e5c963b7
diff --git a/deps/checksums/Pkg-0c3ccb119efd8b3182c114599abe78bc4f89dd4c.tar.gz/md5 b/deps/checksums/Pkg-0c3ccb119efd8b3182c114599abe78bc4f89dd4c.tar.gz/md5
new file mode 100644
index 0000000000000..40286f6e648d9
--- /dev/null
+++ b/deps/checksums/Pkg-0c3ccb119efd8b3182c114599abe78bc4f89dd4c.tar.gz/md5
@@ -0,0 +1 @@
+d6a6ee3e1575e3b0cf64adf6d2c7c28d
diff --git a/deps/checksums/Pkg-0c3ccb119efd8b3182c114599abe78bc4f89dd4c.tar.gz/sha512 b/deps/checksums/Pkg-0c3ccb119efd8b3182c114599abe78bc4f89dd4c.tar.gz/sha512
new file mode 100644
index 0000000000000..1321023fb170b
--- /dev/null
+++ b/deps/checksums/Pkg-0c3ccb119efd8b3182c114599abe78bc4f89dd4c.tar.gz/sha512
@@ -0,0 +1 @@
+3aa17ba7f7a9b76be7a8ddcebfa55c2eb62961c9dd3b4d06551a85fb58cacfcd53a40d2c2dd168f25f8ef5630fb01b3a41537dc9e4b4d54b409fe7d52a748cfa
diff --git a/deps/checksums/libuv-1fcc6d66f9df74189c74d3d390f02202bb7db953.tar.gz/md5 b/deps/checksums/libuv-1fcc6d66f9df74189c74d3d390f02202bb7db953.tar.gz/md5
new file mode 100644
index 0000000000000..ce4beff6c0bc9
--- /dev/null
+++ b/deps/checksums/libuv-1fcc6d66f9df74189c74d3d390f02202bb7db953.tar.gz/md5
@@ -0,0 +1 @@
+9388aa4d36915724f1de4b20b205ed35
diff --git a/deps/checksums/libuv-1fcc6d66f9df74189c74d3d390f02202bb7db953.tar.gz/sha512 b/deps/checksums/libuv-1fcc6d66f9df74189c74d3d390f02202bb7db953.tar.gz/sha512
new file mode 100644
index 0000000000000..863943d5d26bb
--- /dev/null
+++ b/deps/checksums/libuv-1fcc6d66f9df74189c74d3d390f02202bb7db953.tar.gz/sha512
@@ -0,0 +1 @@
+70b0c738a60b4e476750b7de8d120e735359e2c36fcb3a8a38628a0ae326210ed3b15d793dfd5443d7aa5603e83e7d99f567aa4c1696846d950df9f83648669c
diff --git a/deps/libuv.mk b/deps/libuv.mk
index 6e07cea10953e..09523d034d9fd 100644
--- a/deps/libuv.mk
+++ b/deps/libuv.mk
@@ -64,8 +64,8 @@ fastcheck-libuv: #none
 check-libuv: $(LIBUV_BUILDDIR)/build-checked
 
 else # USE_BINARYBUILDER_LIBUV
-LIBUV_BB_URL_BASE := https://github.com/JuliaPackaging/Yggdrasil/releases/download/LibUV-v2+$(LIBUV_VER)-julia+$(LIBUV_BB_REL)
-LIBUV_BB_NAME := LibUV.v2.0.0+$(LIBUV_VER)-julia
+LIBUV_BB_URL_BASE := https://github.com/JuliaBinaryWrappers/LibUV_jll.jl/releases/download/LibUV-v2.0.0+$(LIBUV_BB_REL)
+LIBUV_BB_NAME := LibUV.v2.0.0
 
 $(eval $(call bb-install,libuv,LIBUV,false))
 endif
diff --git a/deps/libuv.version b/deps/libuv.version
index cb4d6b8cad0b3..b410875f69ac9 100644
--- a/deps/libuv.version
+++ b/deps/libuv.version
@@ -1,2 +1,2 @@
 LIBUV_BRANCH=julia-uv2-1.29.1
-LIBUV_SHA1=35b1504507a7a4168caae3d78db54d1121b121e1
+LIBUV_SHA1=1fcc6d66f9df74189c74d3d390f02202bb7db953
diff --git a/doc/src/devdocs/locks.md b/doc/src/devdocs/locks.md
index 8fa3fd4b6dc47..7591f0df2d356 100644
--- a/doc/src/devdocs/locks.md
+++ b/doc/src/devdocs/locks.md
@@ -27,6 +27,7 @@ The following are definitely leaf locks (level 1), and must not try to acquire a
 >   * pagealloc
 >   * gc_perm_lock
 >   * flisp
+>   * jl_in_stackwalk (Win32)
 >
 >     > flisp itself is already threadsafe, this lock only protects the `jl_ast_context_list_t` pool
 
diff --git a/src/datatype.c b/src/datatype.c
index c58c9173bd669..6f9358a2016ec 100644
--- a/src/datatype.c
+++ b/src/datatype.c
@@ -95,6 +95,9 @@ jl_datatype_t *jl_new_uninitialized_datatype(void)
     t->zeroinit = 0;
     t->isinlinealloc = 0;
     t->has_concrete_subtype = 1;
+    t->name = NULL;
+    t->super = NULL;
+    t->parameters = NULL;
     t->layout = NULL;
     t->names = NULL;
     t->types = NULL;
diff --git a/src/debuginfo.cpp b/src/debuginfo.cpp
index 1f81ee114a52f..0c53092d3e3a2 100644
--- a/src/debuginfo.cpp
+++ b/src/debuginfo.cpp
@@ -23,8 +23,6 @@
 
 using namespace llvm;
 
-using llvm_file_magic = file_magic;
-
 #include "julia.h"
 #include "julia_internal.h"
 #include "debuginfo.h"
@@ -55,11 +53,41 @@ typedef object::SymbolRef SymRef;
 // and cannot have any interaction with the julia runtime
 static uv_rwlock_t threadsafe;
 
-extern "C" void jl_init_debuginfo()
+extern "C" void jl_init_debuginfo(void)
 {
     uv_rwlock_init(&threadsafe);
 }
 
+extern "C" void jl_lock_profile(void)
+{
+    uv_rwlock_rdlock(&threadsafe);
+}
+
+extern "C" void jl_unlock_profile(void)
+{
+    uv_rwlock_rdunlock(&threadsafe);
+}
+
+// some actions aren't signal (especially profiler) safe so we acquire a lock
+// around them to establish a mutual exclusion with unwinding from a signal
+template <typename T>
+static void jl_profile_atomic(T f)
+{
+    uv_rwlock_wrlock(&threadsafe);
+#ifndef _OS_WINDOWS_
+    sigset_t sset;
+    sigset_t oset;
+    sigfillset(&sset);
+    pthread_sigmask(SIG_BLOCK, &sset, &oset);
+#endif
+    f();
+#ifndef _OS_WINDOWS_
+    pthread_sigmask(SIG_SETMASK, &oset, NULL);
+#endif
+    uv_rwlock_wrunlock(&threadsafe);
+}
+
+
 // --- storing and accessing source location metadata ---
 
 struct ObjectInfo {
@@ -111,8 +139,7 @@ static void create_PRUNTIME_FUNCTION(uint8_t *Code, size_t Size, StringRef fnnam
     mod_size = Size;
 #endif
     if (0) {
-        assert(!jl_in_stackwalk);
-        jl_in_stackwalk = 1;
+        JL_LOCK_NOGC(&jl_in_stackwalk);
         if (mod_size && !SymLoadModuleEx(GetCurrentProcess(), NULL, NULL, NULL, (DWORD64)Section, mod_size, NULL, SLMFLAG_VIRTUAL)) {
             static int warned = 0;
             if (!warned) {
@@ -132,16 +159,18 @@ static void create_PRUNTIME_FUNCTION(uint8_t *Code, size_t Size, StringRef fnnam
                 jl_printf(JL_STDERR, "WARNING: failed to insert function name %s into debug info: %lu\n", name, GetLastError());
             }
         }
-        jl_in_stackwalk = 0;
+        JL_UNLOCK_NOGC(&jl_in_stackwalk);
     }
 #if defined(_CPU_X86_64_)
-    if (!RtlAddFunctionTable(tbl, 1, (DWORD64)Section)) {
-        static int warned = 0;
-        if (!warned) {
-            jl_printf(JL_STDERR, "WARNING: failed to insert function stack unwind info: %lu\n", GetLastError());
-            warned = 1;
+    jl_profile_atomic([&]() {
+        if (!RtlAddFunctionTable(tbl, 1, (DWORD64)Section)) {
+            static int warned = 0;
+            if (!warned) {
+                jl_printf(JL_STDERR, "WARNING: failed to insert function stack unwind info: %lu\n", GetLastError());
+                warned = 1;
+            }
         }
-    }
+    });
 #endif
 }
 #endif
@@ -279,7 +308,9 @@ class JuliaJITEventListener: public JITEventListener
             di->u.rti.name_ptr = 0;
             di->u.rti.table_data = arm_exidx_addr;
             di->u.rti.table_len = arm_exidx_len;
-            _U_dyn_register(di);
+            jl_profile_atomic([&]() {
+                _U_dyn_register(di);
+            });
             break;
         }
 #endif
@@ -405,20 +436,20 @@ class JuliaJITEventListener: public JITEventListener
                 codeinst = codeinst_it->second;
                 codeinst_in_flight.erase(codeinst_it);
             }
-            uv_rwlock_wrlock(&threadsafe);
-            if (codeinst)
-                linfomap[Addr] = std::make_pair(Size, codeinst->def);
-            if (first) {
-                ObjectInfo tmp = {&debugObj,
-                    (size_t)SectionSize,
-                    (ptrdiff_t)(SectionAddr - SectionLoadAddr),
-                    *Section,
-                    nullptr,
-                    };
-                objectmap[SectionLoadAddr] = tmp;
-                first = false;
-            }
-            uv_rwlock_wrunlock(&threadsafe);
+            jl_profile_atomic([&]() {
+                if (codeinst)
+                    linfomap[Addr] = std::make_pair(Size, codeinst->def);
+                if (first) {
+                    ObjectInfo tmp = {&debugObj,
+                        (size_t)SectionSize,
+                        (ptrdiff_t)(SectionAddr - SectionLoadAddr),
+                        *Section,
+                        nullptr,
+                        };
+                    objectmap[SectionLoadAddr] = tmp;
+                    first = false;
+                }
+            });
         }
         jl_gc_safe_leave(ptls, gc_state);
     }
@@ -432,14 +463,6 @@ class JuliaJITEventListener: public JITEventListener
         uv_rwlock_rdlock(&threadsafe);
         return objectmap;
     }
-
-    Optional<std::map<size_t, ObjectInfo, revcomp>*> trygetObjectMap()
-    {
-        if (0 == uv_rwlock_tryrdlock(&threadsafe)) {
-            return &objectmap;
-        }
-        return {};
-    }
 };
 
 JL_DLLEXPORT void ORCNotifyObjectEmitted(JITEventListener *Listener,
@@ -483,7 +506,7 @@ static std::pair<char *, bool> jl_demangle(const char *name) JL_NOTSAFEPOINT
 }
 
 static JuliaJITEventListener *jl_jit_events;
-JITEventListener *CreateJuliaJITEventListener()
+JITEventListener *CreateJuliaJITEventListener(void)
 {
     jl_jit_events = new JuliaJITEventListener();
     return jl_jit_events;
@@ -723,7 +746,7 @@ openDebugInfo(StringRef debuginfopath, const debug_link_info &info)
 
     auto error_splitobj = object::ObjectFile::createObjectFile(
             SplitFile.get().get()->getMemBufferRef(),
-            llvm_file_magic::unknown);
+            file_magic::unknown);
     if (!error_splitobj) {
         return error_splitobj.takeError();
     }
@@ -832,12 +855,12 @@ static void get_function_name_and_base(llvm::object::SectionRef Section, size_t
         PSYMBOL_INFO pSymbol = (PSYMBOL_INFO)frame_info_func;
         pSymbol->SizeOfStruct = sizeof(SYMBOL_INFO);
         pSymbol->MaxNameLen = MAX_SYM_NAME;
-        jl_in_stackwalk = 1;
+        JL_LOCK_NOGC(&jl_in_stackwalk);
         if (SymFromAddr(GetCurrentProcess(), dwAddress, &dwDisplacement64, pSymbol)) {
             // errors are ignored
             jl_copy_str(name, pSymbol->Name);
         }
-        jl_in_stackwalk = 0;
+        JL_UNLOCK_NOGC(&jl_in_stackwalk);
     }
 #endif
 }
@@ -874,7 +897,7 @@ static objfileentry_t &find_object_file(uint64_t fbase, StringRef fname) JL_NOTS
         std::unique_ptr<MemoryBuffer> membuf = MemoryBuffer::getMemBuffer(
                 StringRef((const char *)fbase, msize), "", false);
         auto origerrorobj = llvm::object::ObjectFile::createObjectFile(
-            membuf->getMemBufferRef(), llvm_file_magic::unknown);
+            membuf->getMemBufferRef(), file_magic::unknown);
         if (!origerrorobj)
             return entry;
 
@@ -1053,6 +1076,7 @@ static object::SectionRef getModuleSectionForAddress(const object::ObjectFile *o
 
 
 extern "C" void jl_refresh_dbg_module_list(void);
+
 bool jl_dylib_DI_for_fptr(size_t pointer, object::SectionRef *Section, int64_t *slide, llvm::DIContext **context,
     bool onlySysImg, bool *isSysImg, void **saddr, char **name, char **filename) JL_NOTSAFEPOINT
 {
@@ -1077,11 +1101,12 @@ bool jl_dylib_DI_for_fptr(size_t pointer, object::SectionRef *Section, int64_t *
 #ifdef _OS_WINDOWS_
     IMAGEHLP_MODULE64 ModuleInfo;
     ModuleInfo.SizeOfStruct = sizeof(IMAGEHLP_MODULE64);
+    JL_LOCK_NOGC(&jl_in_stackwalk);
     jl_refresh_dbg_module_list();
-    jl_in_stackwalk = 1;
     bool isvalid = SymGetModuleInfo64(GetCurrentProcess(), (DWORD64)pointer, &ModuleInfo);
-    jl_in_stackwalk = 0;
-    if (!isvalid) return false;
+    JL_UNLOCK_NOGC(&jl_in_stackwalk);
+    if (!isvalid)
+        return false;
 
     StringRef fname = ModuleInfo.LoadedImageName;
     if (fname.empty()) // empirically, LoadedImageName might be missing
@@ -1147,16 +1172,12 @@ bool jl_dylib_DI_for_fptr(size_t pointer, object::SectionRef *Section, int64_t *
 static int jl_getDylibFunctionInfo(jl_frame_t **frames, size_t pointer, int skipC, int noInline) JL_NOTSAFEPOINT
 {
     // This function is not allowed to reference any TLS variables if noInline
-    // since it can be called from an unmanaged thread on OSX.
+    // since it can be called from an unmanaged thread (the segfault handler)
     jl_frame_t *frame0 = *frames;
 #ifdef _OS_WINDOWS_
     static IMAGEHLP_LINE64 frame_info_line;
     DWORD dwDisplacement = 0;
-    if (jl_in_stackwalk) {
-        frame0->fromC = 1;
-        return 1;
-    }
-    jl_in_stackwalk = 1;
+    JL_LOCK_NOGC(&jl_in_stackwalk);
     DWORD64 dwAddress = pointer;
     frame_info_line.SizeOfStruct = sizeof(IMAGEHLP_LINE64);
     if (SymGetLineFromAddr64(GetCurrentProcess(), dwAddress, &dwDisplacement, &frame_info_line)) {
@@ -1166,7 +1187,7 @@ static int jl_getDylibFunctionInfo(jl_frame_t **frames, size_t pointer, int skip
             jl_copy_str(&frame0->file_name, frame_info_line.FileName);
         frame0->line = frame_info_line.LineNumber;
     }
-    jl_in_stackwalk = 0;
+    JL_UNLOCK_NOGC(&jl_in_stackwalk);
 #endif
     object::SectionRef Section;
     llvm::DIContext *context = NULL;
@@ -1295,11 +1316,13 @@ void register_eh_frames(uint8_t *Addr, size_t Size)
   // See http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-April/061768.html
   processFDEs((char*)Addr, Size, [](const char *Entry) {
         if (!libc_register_frame) {
-          libc_register_frame = (void(*)(void*))dlsym(RTLD_NEXT,"__register_frame");
+          libc_register_frame = (void(*)(void*))dlsym(RTLD_NEXT, "__register_frame");
         }
         assert(libc_register_frame);
-        libc_register_frame(const_cast<char *>(Entry));
-        __register_frame(const_cast<char *>(Entry));
+        jl_profile_atomic([&]() {
+            libc_register_frame(const_cast<char *>(Entry));
+            __register_frame(const_cast<char *>(Entry));
+        });
     });
 }
 
@@ -1307,16 +1330,19 @@ void deregister_eh_frames(uint8_t *Addr, size_t Size)
 {
    processFDEs((char*)Addr, Size, [](const char *Entry) {
         if (!libc_deregister_frame) {
-          libc_deregister_frame = (void(*)(void*))dlsym(RTLD_NEXT,"__deregister_frame");
+          libc_deregister_frame = (void(*)(void*))dlsym(RTLD_NEXT, "__deregister_frame");
         }
         assert(libc_deregister_frame);
-        libc_deregister_frame(const_cast<char *>(Entry));
-        __deregister_frame(const_cast<char *>(Entry));
+        jl_profile_atomic([&]() {
+            libc_deregister_frame(const_cast<char *>(Entry));
+            __deregister_frame(const_cast<char *>(Entry));
+        });
     });
 }
 
 #elif defined(_OS_LINUX_) && \
-    defined(JL_UNW_HAS_FORMAT_IP) && !defined(_CPU_ARM_)
+    defined(JL_UNW_HAS_FORMAT_IP) && \
+    !defined(_CPU_ARM_) // ARM does not have/use .eh_frame, so we handle this elsewhere
 #include <type_traits>
 
 struct unw_table_entry
@@ -1502,7 +1528,9 @@ static DW_EH_PE parseCIE(const uint8_t *Addr, const uint8_t *End)
 void register_eh_frames(uint8_t *Addr, size_t Size)
 {
     // System unwinder
-    __register_frame(Addr);
+    jl_profile_atomic([&]() {
+        __register_frame(Addr);
+    });
     // Our unwinder
     unw_dyn_info_t *di = new unw_dyn_info_t;
     // In a shared library, this is set to the address of the PLT.
@@ -1613,7 +1641,7 @@ void register_eh_frames(uint8_t *Addr, size_t Size)
             start_ips[cur_entry] = start;
             cur_entry++;
         });
-    for (size_t i = 0;i < nentries;i++) {
+    for (size_t i = 0; i < nentries; i++) {
         table[i].start_ip_offset =
             safe_trunc<int32_t>((intptr_t)start_ips[i] - (intptr_t)start_ip);
     }
@@ -1624,27 +1652,21 @@ void register_eh_frames(uint8_t *Addr, size_t Size)
     di->start_ip = start_ip;
     di->end_ip = end_ip;
 
-    _U_dyn_register(di);
+    jl_profile_atomic([&]() {
+        _U_dyn_register(di);
+    });
 }
 
 void deregister_eh_frames(uint8_t *Addr, size_t Size)
 {
-    __deregister_frame(Addr);
-    // Deregistering with our unwinder requires a lookup table to find the
-    // the allocated entry above (or we could look in libunwind's internal
+    jl_profile_atomic([&]() {
+        __deregister_frame(Addr);
+    });
+    // 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).
 }
 
-#elif defined(_CPU_ARM_)
-
-void register_eh_frames(uint8_t *Addr, size_t Size)
-{
-}
-
-void deregister_eh_frames(uint8_t *Addr, size_t Size)
-{
-}
-
 #else
 
 void register_eh_frames(uint8_t *Addr, size_t Size)
@@ -1670,22 +1692,3 @@ uint64_t jl_getUnwindInfo(uint64_t dwAddr)
     uv_rwlock_rdunlock(&threadsafe);
     return ipstart;
 }
-
-extern "C"
-uint64_t jl_trygetUnwindInfo(uint64_t dwAddr)
-{
-    // Might be called from unmanaged thread
-    Optional<std::map<size_t, ObjectInfo, revcomp>*> maybeobjmap = jl_jit_events->trygetObjectMap();
-    if (maybeobjmap) {
-        std::map<size_t, ObjectInfo, revcomp> &objmap = **maybeobjmap;
-        std::map<size_t, ObjectInfo, revcomp>::iterator it = objmap.lower_bound(dwAddr);
-        uint64_t ipstart = 0; // ip of the start of the section (if found)
-        if (it != objmap.end() && dwAddr < it->first + it->second.SectionSize) {
-            ipstart = (uint64_t)(uintptr_t)(*it).first;
-        }
-        uv_rwlock_rdunlock(&threadsafe);
-        return ipstart;
-    }
-    return 0;
-}
-
diff --git a/src/dlload.c b/src/dlload.c
index 72213c4362311..d0bd2c866c080 100644
--- a/src/dlload.c
+++ b/src/dlload.c
@@ -25,7 +25,7 @@ extern "C" {
 static char const *const extensions[] = { "", ".dylib" };
 #elif defined(_OS_WINDOWS_)
 static char const *const extensions[] = { "", ".dll" };
-extern int needsSymRefreshModuleList;
+extern volatile int needsSymRefreshModuleList;
 #else
 static char const *const extensions[] = { "", ".so" };
 #endif
@@ -94,12 +94,14 @@ static void win32_formatmessage(DWORD code, char *reason, int len)
 JL_DLLEXPORT void *jl_dlopen(const char *filename, unsigned flags)
 {
 #if defined(_OS_WINDOWS_)
-    needsSymRefreshModuleList = 1;
     size_t len = MultiByteToWideChar(CP_UTF8, 0, filename, -1, NULL, 0);
     if (!len) return NULL;
     WCHAR *wfilename = (WCHAR*)alloca(len * sizeof(WCHAR));
     if (!MultiByteToWideChar(CP_UTF8, 0, filename, -1, wfilename, len)) return NULL;
-    return LoadLibraryExW(wfilename, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
+    HANDLE lib = LoadLibraryExW(wfilename, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
+    if (lib)
+        needsSymRefreshModuleList = 1;
+    return lib;
 #else
     dlerror(); /* Reset error status. */
     return dlopen(filename,
diff --git a/src/dump.c b/src/dump.c
index f9c0211c61b86..ac81b1a31a2b4 100644
--- a/src/dump.c
+++ b/src/dump.c
@@ -1434,6 +1434,7 @@ static int64_t write_dependency_list(ios_t *s, jl_array_t **udepsp, jl_array_t *
 
 static jl_value_t *jl_deserialize_datatype(jl_serializer_state *s, int pos, jl_value_t **loc) JL_GC_DISABLED
 {
+    assert(pos == backref_list.len - 1 && "nothing should have been deserialized since assigning pos");
     int tag = read_uint8(s->s);
     if (tag == 6 || tag == 7) {
         jl_typename_t *name = (jl_typename_t*)jl_deserialize_value(s, NULL);
@@ -1449,19 +1450,18 @@ static jl_value_t *jl_deserialize_datatype(jl_serializer_state *s, int pos, jl_v
         backref_list.items[pos] = dtv;
         return dtv;
     }
-    size_t size = read_int32(s->s);
-    uint8_t flags = read_uint8(s->s);
-    uint8_t memflags = read_uint8(s->s);
-    jl_datatype_t *dt = NULL;
-    if (tag == 0 || tag == 5 || tag == 10 || tag == 11 || tag == 12)
-        dt = jl_new_uninitialized_datatype();
-    else {
+    if (!(tag == 0 || tag == 5 || tag == 10 || tag == 11 || tag == 12)) {
         assert(0 && "corrupt deserialization state");
         abort();
     }
     assert(s->method == NULL && s->mode != MODE_IR && "no new data-types expected during MODE_IR");
-    assert(pos == backref_list.len - 1 && "nothing should have been deserialized since assigning pos");
+    jl_datatype_t *dt = jl_new_uninitialized_datatype();
     backref_list.items[pos] = dt;
+    if (loc != NULL && loc != HT_NOTFOUND)
+        *loc = (jl_value_t*)dt;
+    size_t size = read_int32(s->s);
+    uint8_t flags = read_uint8(s->s);
+    uint8_t memflags = read_uint8(s->s);
     dt->size = size;
     dt->abstract = flags & 1;
     dt->mutabl = (flags >> 1) & 1;
@@ -1474,11 +1474,6 @@ static jl_value_t *jl_deserialize_datatype(jl_serializer_state *s, int pos, jl_v
     dt->zeroinit = (memflags >> 4) & 1;
     dt->isinlinealloc = (memflags >> 5) & 1;
     dt->has_concrete_subtype = (memflags >> 6) & 1;
-    dt->types = NULL;
-    dt->parameters = NULL;
-    dt->name = NULL;
-    dt->super = NULL;
-    dt->layout = NULL;
     if (!dt->abstract)
         dt->ninitialized = read_uint16(s->s);
     else
@@ -1542,7 +1537,7 @@ static jl_value_t *jl_deserialize_datatype(jl_serializer_state *s, int pos, jl_v
     return (jl_value_t*)dt;
 }
 
-static jl_value_t *jl_deserialize_value_svec(jl_serializer_state *s, uint8_t tag) JL_GC_DISABLED
+static jl_value_t *jl_deserialize_value_svec(jl_serializer_state *s, uint8_t tag, jl_value_t **loc) JL_GC_DISABLED
 {
     int usetable = (s->mode != MODE_IR);
     size_t i, len;
@@ -1550,7 +1545,9 @@ static jl_value_t *jl_deserialize_value_svec(jl_serializer_state *s, uint8_t tag
         len = read_uint8(s->s);
     else
         len = read_int32(s->s);
-    jl_svec_t *sv = jl_alloc_svec_uninit(len);
+    jl_svec_t *sv = jl_alloc_svec(len);
+    if (loc != NULL)
+        *loc = (jl_value_t*)sv;
     if (usetable)
         arraylist_push(&backref_list, (jl_value_t*)sv);
     jl_value_t **data = jl_svec_data(sv);
@@ -2115,7 +2112,7 @@ static jl_value_t *jl_deserialize_value(jl_serializer_state *s, jl_value_t **loc
     case TAG_LONG_METHODROOT:
         return jl_array_ptr_ref(s->method->roots, read_uint16(s->s));
     case TAG_SVEC: JL_FALLTHROUGH; case TAG_LONG_SVEC:
-        return jl_deserialize_value_svec(s, tag);
+        return jl_deserialize_value_svec(s, tag, loc);
     case TAG_COMMONSYM:
         return deser_symbols[read_uint8(s->s)];
     case TAG_SYMBOL: JL_FALLTHROUGH; case TAG_LONG_SYMBOL:
diff --git a/src/init.c b/src/init.c
index 86958049b10db..e4ffc79a9b8f8 100644
--- a/src/init.c
+++ b/src/init.c
@@ -661,6 +661,7 @@ void _julia_init(JL_IMAGE_SEARCH rel)
 #endif
     jl_winsock_handle = jl_dlopen("ws2_32.dll", 0);
     jl_exe_handle = GetModuleHandleA(NULL);
+    JL_MUTEX_INIT(&jl_in_stackwalk);
     SymSetOptions(SYMOPT_UNDNAME | SYMOPT_DEFERRED_LOADS | SYMOPT_LOAD_LINES);
     if (!SymInitialize(GetCurrentProcess(), NULL, 1)) {
         jl_printf(JL_STDERR, "WARNING: failed to initialize stack walk info\n");
diff --git a/src/julia_internal.h b/src/julia_internal.h
index 67df97e4c8212..b917569b080a9 100644
--- a/src/julia_internal.h
+++ b/src/julia_internal.h
@@ -758,7 +758,6 @@ typedef struct {
 
 // Might be called from unmanaged thread
 uint64_t jl_getUnwindInfo(uint64_t dwBase);
-uint64_t jl_trygetUnwindInfo(uint64_t dwBase);
 #ifdef _OS_WINDOWS_
 #include <dbghelp.h>
 JL_DLLEXPORT EXCEPTION_DISPOSITION __julia_personality(
@@ -773,7 +772,7 @@ typedef struct {
     CONTEXT context;
 } bt_cursor_t;
 #endif
-extern volatile int jl_in_stackwalk;
+extern jl_mutex_t jl_in_stackwalk;
 #elif !defined(JL_DISABLE_LIBUNWIND)
 // This gives unwind only local unwinding options ==> faster code
 #  define UNW_LOCAL_ONLY
@@ -795,7 +794,7 @@ size_t rec_backtrace(jl_bt_element_t *bt_data, size_t maxsize, int skip) JL_NOTS
 // Record backtrace from a signal handler. `ctx` is the context of the code
 // 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, int lockless) JL_NOTSAFEPOINT;
+                         jl_gcframe_t *pgcstack) JL_NOTSAFEPOINT;
 #ifdef LIBOSXUNWIND
 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
diff --git a/src/locks.h b/src/locks.h
index 0f011c5e0a7f0..6365eb681ca30 100644
--- a/src/locks.h
+++ b/src/locks.h
@@ -71,6 +71,7 @@ static inline void jl_lock_frame_pop(void)
 {
     jl_ptls_t ptls = jl_get_ptls_states();
     if (__likely(ptls->current_task)) {
+        assert(ptls->current_task->locks.len > 0);
         ptls->current_task->locks.len--;
     }
 }
diff --git a/src/rtutils.c b/src/rtutils.c
index 731a34294940d..f9a8eb59a564e 100644
--- a/src/rtutils.c
+++ b/src/rtutils.c
@@ -610,6 +610,43 @@ JL_DLLEXPORT jl_value_t *jl_argument_datatype(jl_value_t *argt JL_PROPAGATES_ROO
     return (jl_value_t*)dt;
 }
 
+static int is_globfunction(jl_value_t *v, jl_datatype_t *dv, jl_sym_t **globname_out)
+{
+    jl_sym_t *globname = dv->name->mt != NULL ? dv->name->mt->name : NULL;
+    *globname_out = globname;
+    int globfunc = 0;
+    if (globname && !strchr(jl_symbol_name(globname), '#') &&
+        !strchr(jl_symbol_name(globname), '@') && dv->name->module &&
+        jl_binding_resolved_p(dv->name->module, globname)) {
+        jl_binding_t *b = jl_get_module_binding(dv->name->module, globname);
+        // The `||` makes this function work for both function instances and function types.
+        if (b && b->value && (b->value == v || jl_typeof(b->value) == v)) {
+            globfunc = 1;
+        }
+    }
+    return globfunc;
+}
+
+static size_t jl_static_show_x_sym_escaped(JL_STREAM *out, jl_sym_t *name) JL_NOTSAFEPOINT
+{
+    size_t n = 0;
+
+    char *sn = jl_symbol_name(name);
+    int hidden = 0;
+    if (!(jl_is_identifier(sn) || jl_is_operator(sn))) {
+        hidden = 1;
+    }
+
+    if (hidden) {
+        n += jl_printf(out, "var\"");
+    }
+    n += jl_printf(out, "%s", sn);
+    if (hidden) {
+        n += jl_printf(out, "\"");
+    }
+    return n;
+}
+
 // `v` might be pointing to a field inlined in a structure therefore
 // `jl_typeof(v)` may not be the same with `vt` and only `vt` should be
 // used to determine the type of the value.
@@ -678,48 +715,32 @@ static size_t jl_static_show_x_(JL_STREAM *out, jl_value_t *v, jl_datatype_t *vt
         n += jl_printf(out, "UnionAll");
     }
     else if (vt == jl_datatype_type) {
+        // typeof(v) == DataType, so v is a Type object.
+        // Types are printed as a fully qualified name, with parameters, e.g.
+        // `Base.Set{Int}`, and function types are printed as e.g. `typeof(Main.f)`
         jl_datatype_t *dv = (jl_datatype_t*)v;
-        jl_sym_t *globname = dv->name->mt != NULL ? dv->name->mt->name : NULL;
-        int globfunc = 0;
-        if (globname && !strchr(jl_symbol_name(globname), '#') &&
-            !strchr(jl_symbol_name(globname), '@') && dv->name->module &&
-            jl_binding_resolved_p(dv->name->module, globname)) {
-            jl_binding_t *b = jl_get_module_binding(dv->name->module, globname);
-            if (b && b->value && jl_typeof(b->value) == v)
-                globfunc = 1;
-        }
+        jl_sym_t *globname;
+        int globfunc = is_globfunction(v, dv, &globname);
         jl_sym_t *sym = globfunc ? globname : dv->name->name;
         char *sn = jl_symbol_name(sym);
-        int hidden = !globfunc && strchr(sn, '#');
-        size_t i = 0;
-        int quote = 0;
-        if (hidden) {
-            n += jl_printf(out, "getfield(");
-        }
-        else if (globfunc) {
+        size_t quote = 0;
+        if (globfunc) {
             n += jl_printf(out, "typeof(");
         }
         if (jl_core_module && (dv->name->module != jl_core_module || !jl_module_exports_p(jl_core_module, sym))) {
             n += jl_static_show_x(out, (jl_value_t*)dv->name->module, depth);
-            if (!hidden) {
-                n += jl_printf(out, ".");
-                if (globfunc && !jl_id_start_char(u8_nextchar(sn, &i))) {
-                    n += jl_printf(out, ":(");
-                    quote = 1;
-                }
+            n += jl_printf(out, ".");
+            size_t i = 0;
+            if (globfunc && !jl_id_start_char(u8_nextchar(sn, &i))) {
+                n += jl_printf(out, ":(");
+                quote = 1;
             }
         }
-        if (hidden) {
-            n += jl_printf(out, ", Symbol(\"");
-            n += jl_printf(out, "%s", sn);
-            n += jl_printf(out, "\"))");
-        }
-        else {
-            n += jl_printf(out, "%s", sn);
-            if (globfunc) {
+        n += jl_static_show_x_sym_escaped(out, sym);
+        if (globfunc) {
+            n += jl_printf(out, ")");
+            if (quote) {
                 n += jl_printf(out, ")");
-                if (quote)
-                    n += jl_printf(out, ")");
             }
         }
         if (dv->parameters && (jl_value_t*)dv != dv->name->wrapper &&
@@ -835,7 +856,7 @@ static size_t jl_static_show_x_(JL_STREAM *out, jl_value_t *v, jl_datatype_t *vt
                 n += jl_printf(out, ")");
             n += jl_printf(out, "<:");
         }
-        n += jl_printf(out, "%s", jl_symbol_name(var->name));
+        n += jl_static_show_x_sym_escaped(out, var->name);
         if (showbounds && (ub != (jl_value_t*)jl_any_type || lb != jl_bottom_type)) {
             // show type-var upper bound if it is defined, or if we showed the lower bound
             int ua = jl_is_unionall(ub);
@@ -981,7 +1002,38 @@ static size_t jl_static_show_x_(JL_STREAM *out, jl_value_t *v, jl_datatype_t *vt
         n += jl_static_show_x(out, *(jl_value_t**)v, depth);
         n += jl_printf(out, ")");
     }
+    else if (jl_function_type && jl_isa(v, (jl_value_t*)jl_function_type)) {
+        // v is function instance (an instance of a Function type).
+        jl_datatype_t *dv = (jl_datatype_t*)vt;
+        jl_sym_t *sym = dv->name->mt->name;
+        char *sn = jl_symbol_name(sym);
+
+        jl_sym_t *globname;
+        int globfunc = is_globfunction(v, dv, &globname);
+        int quote = 0;
+        if (jl_core_module && (dv->name->module != jl_core_module || !jl_module_exports_p(jl_core_module, sym))) {
+            n += jl_static_show_x(out, (jl_value_t*)dv->name->module, depth);
+            n += jl_printf(out, ".");
+
+            size_t i = 0;
+            if (globfunc && !jl_id_start_char(u8_nextchar(sn, &i))) {
+                n += jl_printf(out, ":(");
+                quote = 1;
+            }
+        }
+
+        n += jl_static_show_x_sym_escaped(out, sym);
+
+        if (globfunc) {
+            if (quote) {
+                n += jl_printf(out, ")");
+            }
+        }
+    }
     else if (jl_datatype_type && jl_is_datatype(vt)) {
+        // typeof(v) isa DataType, so v is an *instance of* a type that is a Datatype,
+        // meaning v is e.g. an instance of a struct. These are printed as a call to a
+        // type constructor, such as e.g. `Base.UnitRange{Int64}(start=1, stop=2)`
         int istuple = jl_is_tuple_type(vt), isnamedtuple = jl_is_namedtuple_type(vt);
         size_t tlen = jl_datatype_nfields(vt);
         if (isnamedtuple) {
diff --git a/src/signal-handling.c b/src/signal-handling.c
index 148b1598c2996..53ef1a56b861e 100644
--- a/src/signal-handling.c
+++ b/src/signal-handling.c
@@ -27,6 +27,8 @@ static const    uint64_t GIGA = 1000000000ULL;
 // Timers to take samples at intervals
 JL_DLLEXPORT void jl_profile_stop_timer(void);
 JL_DLLEXPORT int jl_profile_start_timer(void);
+void jl_lock_profile(void);
+void jl_unlock_profile(void);
 
 static uint64_t jl_last_sigint_trigger = 0;
 static uint64_t jl_disable_sigint_time = 0;
@@ -233,7 +235,7 @@ void jl_critical_error(int sig, bt_context_t *context, jl_bt_element_t *bt_data,
     if (context) {
         // Must avoid extended backtrace frames here unless we're sure bt_data
         // is properly rooted.
-        *bt_size = n = rec_backtrace_ctx(bt_data, JL_MAX_BT_SIZE, context, NULL, 1);
+        *bt_size = n = rec_backtrace_ctx(bt_data, JL_MAX_BT_SIZE, context, NULL);
     }
     for (i = 0; i < n; i += jl_bt_entry_size(bt_data + i)) {
         jl_print_bt_entry_codeloc(bt_data + i);
diff --git a/src/signals-mach.c b/src/signals-mach.c
index 280ce00236624..f523420cc8342 100644
--- a/src/signals-mach.c
+++ b/src/signals-mach.c
@@ -17,6 +17,18 @@
 
 #include "julia_assert.h"
 
+// private keymgr stuff
+#define KEYMGR_GCC3_DW2_OBJ_LIST 302
+enum {
+  NM_ALLOW_RECURSION = 1,
+  NM_RECURSION_ILLEGAL = 2
+};
+extern void _keymgr_set_and_unlock_processwide_ptr(unsigned int key, void *ptr);
+extern int _keymgr_unlock_processwide_ptr(unsigned int key);
+extern void *_keymgr_get_and_lock_processwide_ptr(unsigned int key);
+extern int _keymgr_get_and_lock_processwide_ptr_2(unsigned int key, void **result);
+extern int _keymgr_set_lockmode_processwide_ptr(unsigned int key, unsigned int mode);
+
 static void attach_exception_port(thread_port_t thread, int segv_only);
 
 // low 16 bits are the thread id, the next 8 bits are the original gc_state
@@ -78,6 +90,17 @@ void *mach_segv_listener(void *arg)
 
 static void allocate_segv_handler()
 {
+    // ensure KEYMGR_GCC3_DW2_OBJ_LIST is initialized, as this requires malloc
+    // and thus can deadlock when used without first initializing it.
+    // Apple caused this problem in their libunwind in 10.9 (circa keymgr-28)
+    // when they removed this part of the code from keymgr.
+    // Much thanks to Apple for providing source code, or this would probably
+    // have simply remained unsolved forever on their platform.
+    // This is similar to just calling checkKeyMgrRegisteredFDEs
+    // (this is quite thread-unsafe)
+    if (_keymgr_set_lockmode_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST, NM_ALLOW_RECURSION))
+        jl_error("_keymgr_set_lockmode_processwide_ptr failed");
+
     arraylist_new(&suspended_threads, jl_n_threads);
     pthread_t thread;
     pthread_attr_t attr;
@@ -142,7 +165,7 @@ static void jl_throw_in_thread(int tid, mach_port_t thread, jl_value_t *exceptio
     if (!ptls2->safe_restore) {
         assert(exception);
         ptls2->bt_size = rec_backtrace_ctx(ptls2->bt_data, JL_MAX_BT_SIZE,
-                                           (bt_context_t*)&state, ptls2->pgcstack, 0);
+                                           (bt_context_t*)&state, ptls2->pgcstack);
         ptls2->sig_exception = exception;
     }
     jl_call_in_state(ptls2, &state, &jl_sig_throw);
@@ -420,6 +443,9 @@ void *mach_profile_listener(void *arg)
         HANDLE_MACH_ERROR("mach_msg", ret);
         // sample each thread, round-robin style in reverse order
         // (so that thread zero gets notified last)
+        jl_lock_profile();
+        void *unused = NULL;
+        int keymgr_locked = _keymgr_get_and_lock_processwide_ptr_2(KEYMGR_GCC3_DW2_OBJ_LIST, &unused) == 0;
         for (i = jl_n_threads; i-- > 0; ) {
             // if there is no space left, break early
             if (bt_size_cur >= bt_size_max - 1)
@@ -448,7 +474,7 @@ void *mach_profile_listener(void *arg)
 
                 if (forceDwarf == 0) {
                     // Save the backtrace
-                    bt_size_cur += rec_backtrace_ctx((jl_bt_element_t*)bt_data_prof + bt_size_cur, bt_size_max - bt_size_cur - 1, uc, NULL, 1);
+                    bt_size_cur += rec_backtrace_ctx((jl_bt_element_t*)bt_data_prof + bt_size_cur, bt_size_max - bt_size_cur - 1, uc, NULL);
                 }
                 else if (forceDwarf == 1) {
                     bt_size_cur += rec_backtrace_ctx_dwarf((jl_bt_element_t*)bt_data_prof + bt_size_cur, bt_size_max - bt_size_cur - 1, uc, NULL);
@@ -464,14 +490,18 @@ void *mach_profile_listener(void *arg)
 
                 // Mark the end of this block with 0
                 bt_data_prof[bt_size_cur++].uintptr = 0;
-
-                // Reset the alarm
-                kern_return_t ret = clock_alarm(clk, TIME_RELATIVE, timerprof, profile_port);
-                HANDLE_MACH_ERROR("clock_alarm", ret)
             }
             // We're done! Resume the thread.
             jl_thread_resume(i, 0);
         }
+        if (keymgr_locked)
+            _keymgr_unlock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST);
+        jl_unlock_profile();
+        if (running) {
+            // Reset the alarm
+            kern_return_t ret = clock_alarm(clk, TIME_RELATIVE, timerprof, profile_port);
+            HANDLE_MACH_ERROR("clock_alarm", ret)
+        }
     }
 }
 
@@ -505,6 +535,7 @@ JL_DLLEXPORT int jl_profile_start_timer(void)
     timerprof.tv_nsec = nsecprof%GIGA;
 
     running = 1;
+    // ensure the alarm is running
     ret = clock_alarm(clk, TIME_RELATIVE, timerprof, profile_port);
     HANDLE_MACH_ERROR("clock_alarm", ret);
 
diff --git a/src/signals-unix.c b/src/signals-unix.c
index cd86a77023347..68eb1f5da22f8 100644
--- a/src/signals-unix.c
+++ b/src/signals-unix.c
@@ -176,7 +176,7 @@ static void jl_throw_in_ctx(jl_ptls_t ptls, jl_value_t *e, int sig, void *sigctx
 {
     if (!ptls->safe_restore)
         ptls->bt_size = rec_backtrace_ctx(ptls->bt_data, JL_MAX_BT_SIZE,
-                                          jl_to_bt_context(sigctx), ptls->pgcstack, 0);
+                                          jl_to_bt_context(sigctx), ptls->pgcstack);
     ptls->sig_exception = e;
     jl_call_in_ctx(ptls, &jl_sig_throw, sig, sigctx);
 }
@@ -665,6 +665,8 @@ static void *signal_listener(void *arg)
         unw_context_t *signal_context;
         // sample each thread, round-robin style in reverse order
         // (so that thread zero gets notified last)
+        if (critical || profile)
+            jl_lock_profile();
         for (int i = jl_n_threads; i-- > 0; ) {
             // notify thread to stop
             jl_thread_suspend_and_get_state(i, &signal_context);
@@ -674,7 +676,7 @@ static void *signal_listener(void *arg)
             if (critical) {
                 bt_size += rec_backtrace_ctx(bt_data + bt_size,
                         JL_MAX_BT_SIZE / jl_n_threads - 1,
-                        signal_context, NULL, 1);
+                        signal_context, NULL);
                 bt_data[bt_size++].uintptr = 0;
             }
 
@@ -693,7 +695,7 @@ static void *signal_listener(void *arg)
                     } else {
                         // Get backtrace data
                         bt_size_cur += rec_backtrace_ctx((jl_bt_element_t*)bt_data_prof + bt_size_cur,
-                                bt_size_max - bt_size_cur - 1, signal_context, NULL, 1);
+                                bt_size_max - bt_size_cur - 1, signal_context, NULL);
                     }
                     ptls->safe_restore = old_buf;
 
@@ -709,6 +711,8 @@ static void *signal_listener(void *arg)
             // notify thread to resume
             jl_thread_resume(i, sig);
         }
+        if (critical || profile)
+            jl_unlock_profile();
 #endif
 
         // this part is async with the running of the rest of the program
diff --git a/src/signals-win.c b/src/signals-win.c
index 09a8a546e4362..9ea8a38813ff3 100644
--- a/src/signals-win.c
+++ b/src/signals-win.c
@@ -96,15 +96,18 @@ void __cdecl crt_sig_handler(int sig, int num)
     }
 }
 
+// StackOverflowException needs extra stack space to record the backtrace
+// so we keep one around, shared by all threads
+static jl_mutex_t backtrace_lock;
 static jl_ucontext_t collect_backtrace_fiber;
 static jl_ucontext_t error_return_fiber;
-static PCONTEXT error_ctx;
+static PCONTEXT stkerror_ctx;
+static jl_ptls_t stkerror_ptls;
 static int have_backtrace_fiber;
 static void JL_NORETURN start_backtrace_fiber(void)
 {
-    jl_ptls_t ptls = jl_get_ptls_states();
     // collect the backtrace
-    ptls->bt_size = rec_backtrace_ctx(ptls->bt_data, JL_MAX_BT_SIZE, error_ctx, ptls->pgcstack, 0);
+    stkerror_ptls->bt_size = rec_backtrace_ctx(stkerror_ptls->bt_data, JL_MAX_BT_SIZE, stkerror_ctx, stkerror_ptls->pgcstack);
     // switch back to the execution fiber
     jl_setcontext(&error_return_fiber);
     abort();
@@ -130,11 +133,14 @@ void jl_throw_in_ctx(jl_value_t *excpt, PCONTEXT ctxThread)
         assert(excpt != NULL);
         ptls->bt_size = 0;
         if (excpt != jl_stackovf_exception) {
-            ptls->bt_size = rec_backtrace_ctx(ptls->bt_data, JL_MAX_BT_SIZE, ctxThread, ptls->pgcstack, 0);
+            ptls->bt_size = rec_backtrace_ctx(ptls->bt_data, JL_MAX_BT_SIZE, ctxThread, ptls->pgcstack);
         }
         else if (have_backtrace_fiber) {
-            error_ctx = ctxThread;
+            JL_LOCK(&backtrace_lock);
+            stkerror_ctx = ctxThread;
+            stkerror_ptls = ptls;
             jl_swapcontext(&error_return_fiber, &collect_backtrace_fiber);
+            JL_UNLOCK_NOGC(&backtrace_lock);
         }
         ptls->sig_exception = excpt;
     }
@@ -155,13 +161,16 @@ HANDLE hMainThread = INVALID_HANDLE_VALUE;
 static void jl_try_deliver_sigint(void)
 {
     jl_ptls_t ptls2 = jl_all_tls_states[0];
+    jl_lock_profile();
     jl_safepoint_enable_sigint();
     jl_wake_libuv();
     if ((DWORD)-1 == SuspendThread(hMainThread)) {
         // error
         jl_safe_printf("error: SuspendThread failed\n");
+        jl_unlock_profile();
         return;
     }
+    jl_unlock_profile();
     int force = jl_check_force_sigint();
     if (force || (!ptls2->defer_signal && ptls2->io_wait)) {
         jl_safepoint_consume_sigint();
@@ -326,11 +335,14 @@ static DWORD WINAPI profile_bt( LPVOID lparam )
         hBtThread = 0;
         return 0;
     }
+    timeBeginPeriod(tc.wPeriodMin);
     while (1) {
-        if (bt_size_cur < bt_size_max) {
-            DWORD timeout = nsecprof/GIGA;
-            timeout = min(max(timeout, tc.wPeriodMin*2), tc.wPeriodMax/2);
-            Sleep(timeout);
+        DWORD timeout = nsecprof / GIGA;
+        timeout += tc.wPeriodMin;
+        Sleep(timeout);
+        if (bt_size_cur < bt_size_max && running) {
+            JL_LOCK_NOGC(&jl_in_stackwalk);
+            jl_lock_profile();
             if ((DWORD)-1 == SuspendThread(hMainThread)) {
                 fputs("failed to suspend main thread. aborting profiling.", stderr);
                 break;
@@ -341,25 +353,35 @@ static DWORD WINAPI profile_bt( LPVOID lparam )
                 ctxThread.ContextFlags = CONTEXT_CONTROL | CONTEXT_INTEGER;
                 if (!GetThreadContext(hMainThread, &ctxThread)) {
                     fputs("failed to get context from main thread. aborting profiling.", stderr);
-                    break;
+                    running = 0;
+                }
+                else {
+                    // Get backtrace data
+                    bt_size_cur += rec_backtrace_ctx((jl_bt_element_t*)bt_data_prof + bt_size_cur,
+                            bt_size_max - bt_size_cur - 1, &ctxThread, NULL);
+                    // Mark the end of this block with 0
+                    if (bt_size_cur < bt_size_max)
+                        bt_data_prof[bt_size_cur++].uintptr = 0;
                 }
-                // Get backtrace data
-                bt_size_cur += rec_backtrace_ctx((jl_bt_element_t*)bt_data_prof + bt_size_cur,
-                    bt_size_max - bt_size_cur - 1, &ctxThread, NULL, 1);
-                // Mark the end of this block with 0
-                bt_data_prof[bt_size_cur].uintptr = 0;
-                bt_size_cur++;
             }
+            jl_unlock_profile();
+            JL_UNLOCK_NOGC(&jl_in_stackwalk);
             if ((DWORD)-1 == ResumeThread(hMainThread)) {
+                timeEndPeriod(tc.wPeriodMin);
                 fputs("failed to resume main thread! aborting.", stderr);
                 gc_debug_critical_error();
                 abort();
             }
         }
         else {
+            timeEndPeriod(tc.wPeriodMin);
             SuspendThread(GetCurrentThread());
+            timeBeginPeriod(tc.wPeriodMin);
         }
     }
+    jl_unlock_profile();
+    JL_UNLOCK_NOGC(&jl_in_stackwalk);
+    timeEndPeriod(tc.wPeriodMin);
     hBtThread = 0;
     return 0;
 }
@@ -379,7 +401,7 @@ JL_DLLEXPORT int jl_profile_start_timer(void)
     }
     else {
         if ((DWORD)-1 == ResumeThread(hBtThread)) {
-            fputs("failed to resume profiling thread.",stderr);
+            fputs("failed to resume profiling thread.", stderr);
             return -2;
         }
     }
@@ -420,5 +442,6 @@ void jl_install_thread_signal_handler(jl_ptls_t ptls)
     collect_backtrace_fiber.uc_stack.ss_sp = (void*)stk;
     collect_backtrace_fiber.uc_stack.ss_size = ssize;
     jl_makecontext(&collect_backtrace_fiber, start_backtrace_fiber);
+    JL_MUTEX_INIT(&backtrace_lock);
     have_backtrace_fiber = 1;
 }
diff --git a/src/stackwalk.c b/src/stackwalk.c
index ecff626e9a03e..95ecaff38462f 100644
--- a/src/stackwalk.c
+++ b/src/stackwalk.c
@@ -13,6 +13,7 @@
 // define `jl_unw_get` as a macro, since (like setjmp)
 // returning from the callee function will invalidate the context
 #ifdef _OS_WINDOWS_
+jl_mutex_t jl_in_stackwalk;
 #define jl_unw_get(context) RtlCaptureContext(context)
 #elif !defined(JL_DISABLE_LIBUNWIND)
 #define jl_unw_get(context) unw_getcontext(context)
@@ -24,8 +25,8 @@ void jl_unw_get(void *context) {};
 extern "C" {
 #endif
 
-static int jl_unw_init(bt_cursor_t *cursor, bt_context_t *context, int lockless) JL_NOTSAFEPOINT;
-static int jl_unw_step(bt_cursor_t *cursor, uintptr_t *ip, uintptr_t *sp, int lockless) JL_NOTSAFEPOINT;
+static int jl_unw_init(bt_cursor_t *cursor, bt_context_t *context) JL_NOTSAFEPOINT;
+static int jl_unw_step(bt_cursor_t *cursor, uintptr_t *ip, uintptr_t *sp) JL_NOTSAFEPOINT;
 
 static jl_gcframe_t *is_enter_interpreter_frame(jl_gcframe_t **ppgcstack, uintptr_t sp) JL_NOTSAFEPOINT
 {
@@ -67,15 +68,14 @@ static jl_gcframe_t *is_enter_interpreter_frame(jl_gcframe_t **ppgcstack, uintpt
 // elements written to bt_data (and sp if non-NULL) are returned in bt_size.
 int jl_unw_stepn(bt_cursor_t *cursor, jl_bt_element_t *bt_data, size_t *bt_size,
                  uintptr_t *sp, size_t maxsize, int skip, jl_gcframe_t **ppgcstack,
-                 int from_signal_handler, int lockless) JL_NOTSAFEPOINT
+                 int from_signal_handler) JL_NOTSAFEPOINT
 {
     volatile size_t n = 0;
     volatile int need_more_space = 0;
     uintptr_t return_ip = 0;
     uintptr_t thesp = 0;
 #if defined(_OS_WINDOWS_) && !defined(_CPU_X86_64_)
-    assert(!jl_in_stackwalk);
-    jl_in_stackwalk = 1;
+    JL_LOCK_NOGC(&jl_in_stackwalk);
     if (!from_signal_handler) {
         // Workaround 32-bit windows bug missing top frame
         // See for example https://bugs.chromium.org/p/crashpad/issues/detail?id=53
@@ -96,7 +96,7 @@ int jl_unw_stepn(bt_cursor_t *cursor, jl_bt_element_t *bt_data, size_t *bt_size,
                 need_more_space = 1;
                 break;
             }
-            have_more_frames = jl_unw_step(cursor, &return_ip, &thesp, lockless);
+            have_more_frames = jl_unw_step(cursor, &return_ip, &thesp);
             if (skip > 0) {
                 skip--;
                 continue;
@@ -172,20 +172,20 @@ int jl_unw_stepn(bt_cursor_t *cursor, jl_bt_element_t *bt_data, size_t *bt_size,
     ptls->safe_restore = old_buf;
 #endif
 #if defined(_OS_WINDOWS_) && !defined(_CPU_X86_64_)
-    jl_in_stackwalk = 0;
+    JL_UNLOCK_NOGC(&jl_in_stackwalk);
 #endif
     *bt_size = n;
     return need_more_space;
 }
 
 NOINLINE size_t rec_backtrace_ctx(jl_bt_element_t *bt_data, size_t maxsize,
-                                  bt_context_t *context, jl_gcframe_t *pgcstack, int lockless) JL_NOTSAFEPOINT
+                                  bt_context_t *context, jl_gcframe_t *pgcstack) JL_NOTSAFEPOINT
 {
     bt_cursor_t cursor;
-    if (!jl_unw_init(&cursor, context, lockless))
+    if (!jl_unw_init(&cursor, context))
         return 0;
     size_t bt_size = 0;
-    jl_unw_stepn(&cursor, bt_data, &bt_size, NULL, maxsize, 0, &pgcstack, 1, lockless);
+    jl_unw_stepn(&cursor, bt_data, &bt_size, NULL, maxsize, 0, &pgcstack, 1);
     return bt_size;
 }
 
@@ -201,10 +201,10 @@ NOINLINE size_t rec_backtrace(jl_bt_element_t *bt_data, size_t maxsize, int skip
     jl_unw_get(&context);
     jl_gcframe_t *pgcstack = jl_pgcstack;
     bt_cursor_t cursor;
-    if (!jl_unw_init(&cursor, &context, 0))
+    if (!jl_unw_init(&cursor, &context))
         return 0;
     size_t bt_size = 0;
-    jl_unw_stepn(&cursor, bt_data, &bt_size, NULL, maxsize, skip + 1, &pgcstack, 0, 0);
+    jl_unw_stepn(&cursor, bt_data, &bt_size, NULL, maxsize, skip + 1, &pgcstack, 0);
     return bt_size;
 }
 
@@ -235,7 +235,7 @@ JL_DLLEXPORT jl_value_t *jl_backtrace_from_here(int returnsp, int skip)
     memset(&context, 0, sizeof(context));
     jl_unw_get(&context);
     jl_gcframe_t *pgcstack = jl_pgcstack;
-    if (jl_unw_init(&cursor, &context, 0)) {
+    if (jl_unw_init(&cursor, &context)) {
         // Skip frame for jl_backtrace_from_here itself
         skip += 1;
         size_t offset = 0;
@@ -249,7 +249,7 @@ JL_DLLEXPORT jl_value_t *jl_backtrace_from_here(int returnsp, int skip)
             }
             size_t size_incr = 0;
             have_more_frames = jl_unw_stepn(&cursor, (jl_bt_element_t*)jl_array_data(ip) + offset,
-                                            &size_incr, sp_ptr, maxincr, skip, &pgcstack, 0, 0);
+                                            &size_incr, sp_ptr, maxincr, skip, &pgcstack, 0);
             skip = 0;
             offset += size_incr;
         }
@@ -359,6 +359,7 @@ JL_DLLEXPORT jl_value_t *jl_get_excstack(jl_task_t* task, int include_bt, int ma
 }
 
 #if defined(_OS_WINDOWS_)
+// XXX: these caches should be per-thread
 #ifdef _CPU_X86_64_
 static UNWIND_HISTORY_TABLE HistoryTable;
 #else
@@ -375,13 +376,11 @@ static PVOID CALLBACK JuliaFunctionTableAccess64(
 #ifdef _CPU_X86_64_
     DWORD64 ImageBase;
     PRUNTIME_FUNCTION fn = RtlLookupFunctionEntry(AddrBase, &ImageBase, &HistoryTable);
-    if (fn) return fn;
-    if (jl_in_stackwalk) {
-        return 0;
-    }
-    jl_in_stackwalk = 1;
+    if (fn)
+        return fn;
+    JL_LOCK_NOGC(&jl_in_stackwalk);
     PVOID ftable = SymFunctionTableAccess64(hProcess, AddrBase);
-    jl_in_stackwalk = 0;
+    JL_UNLOCK_NOGC(&jl_in_stackwalk);
     return ftable;
 #else
     return SymFunctionTableAccess64(hProcess, AddrBase);
@@ -395,16 +394,15 @@ static DWORD64 WINAPI JuliaGetModuleBase64(
 #ifdef _CPU_X86_64_
     DWORD64 ImageBase;
     PRUNTIME_FUNCTION fn = RtlLookupFunctionEntry(dwAddr, &ImageBase, &HistoryTable);
-    if (fn) return ImageBase;
-    if (jl_in_stackwalk) {
-        return 0;
-    }
-    jl_in_stackwalk = 1;
+    if (fn)
+        return ImageBase;
+    JL_LOCK_NOGC(&jl_in_stackwalk);
     DWORD64 fbase = SymGetModuleBase64(hProcess, dwAddr);
-    jl_in_stackwalk = 0;
+    JL_UNLOCK_NOGC(&jl_in_stackwalk);
     return fbase;
 #else
-    if (dwAddr == HistoryTable.dwAddr) return HistoryTable.ImageBase;
+    if (dwAddr == HistoryTable.dwAddr)
+        return HistoryTable.ImageBase;
     DWORD64 ImageBase = jl_getUnwindInfo(dwAddr);
     if (ImageBase) {
         HistoryTable.dwAddr = dwAddr;
@@ -415,45 +413,23 @@ static DWORD64 WINAPI JuliaGetModuleBase64(
 #endif
 }
 
-static DWORD64 WINAPI JuliaAsyncGetModuleBase64(
-        _In_  HANDLE hProcess,
-        _In_  DWORD64 dwAddr)
-{
-    //jl_printf(JL_STDOUT, "lookup base %d\n", dwAddr);
-#ifdef _CPU_X86_64_
-    return JuliaGetModuleBase64(hProcess, dwAddr);
-#else
-    if (dwAddr == HistoryTable.dwAddr) return HistoryTable.ImageBase;
-    DWORD64 ImageBase = jl_trygetUnwindInfo(dwAddr);
-    if (ImageBase) {
-        HistoryTable.dwAddr = dwAddr;
-        HistoryTable.ImageBase = ImageBase;
-        return ImageBase;
-    }
-    return SymGetModuleBase64(hProcess, dwAddr);
-#endif
-}
-
 // Might be called from unmanaged thread.
-int needsSymRefreshModuleList;
+volatile int needsSymRefreshModuleList;
 BOOL (WINAPI *hSymRefreshModuleList)(HANDLE);
+
 void jl_refresh_dbg_module_list(void)
 {
-    if (needsSymRefreshModuleList && hSymRefreshModuleList != 0 && !jl_in_stackwalk) {
-        jl_in_stackwalk = 1;
+    if (needsSymRefreshModuleList && hSymRefreshModuleList != NULL) {
         hSymRefreshModuleList(GetCurrentProcess());
-        jl_in_stackwalk = 0;
         needsSymRefreshModuleList = 0;
     }
 }
-static int jl_unw_init(bt_cursor_t *cursor, bt_context_t *Context, int lockless)
+static int jl_unw_init(bt_cursor_t *cursor, bt_context_t *Context)
 {
+    int result;
+    JL_LOCK_NOGC(&jl_in_stackwalk);
     jl_refresh_dbg_module_list();
 #if !defined(_CPU_X86_64_)
-    if (jl_in_stackwalk) {
-        return 0;
-    }
-    jl_in_stackwalk = 1;
     memset(&cursor->stackframe, 0, sizeof(cursor->stackframe));
     cursor->stackframe.AddrPC.Offset = Context->Eip;
     cursor->stackframe.AddrStack.Offset = Context->Esp;
@@ -462,15 +438,15 @@ static int jl_unw_init(bt_cursor_t *cursor, bt_context_t *Context, int lockless)
     cursor->stackframe.AddrStack.Mode = AddrModeFlat;
     cursor->stackframe.AddrFrame.Mode = AddrModeFlat;
     cursor->context = *Context;
-    BOOL result = StackWalk64(IMAGE_FILE_MACHINE_I386, GetCurrentProcess(), hMainThread,
-        &cursor->stackframe, &cursor->context, NULL, JuliaFunctionTableAccess64,
-            lockless ? JuliaAsyncGetModuleBase64 : JuliaGetModuleBase64, NULL);
-    jl_in_stackwalk = 0;
-    return result;
+    result = StackWalk64(IMAGE_FILE_MACHINE_I386, GetCurrentProcess(), hMainThread,
+            &cursor->stackframe, &cursor->context, NULL, JuliaFunctionTableAccess64,
+            JuliaGetModuleBase64, NULL);
 #else
     *cursor = *Context;
-    return 1;
+    result = 1;
 #endif
+    JL_UNLOCK_NOGC(&jl_in_stackwalk);
+    return result;
 }
 
 static int readable_pointer(LPCVOID pointer)
@@ -487,10 +463,8 @@ static int readable_pointer(LPCVOID pointer)
     return 1;
 }
 
-static int jl_unw_step(bt_cursor_t *cursor, uintptr_t *ip, uintptr_t *sp, int lockless)
+static int jl_unw_step(bt_cursor_t *cursor, uintptr_t *ip, uintptr_t *sp)
 {
-    DWORD64 WINAPI (*GetModuleBase64)(HANDLE, DWORD64) = lockless ?
-        JuliaAsyncGetModuleBase64 : JuliaGetModuleBase64;
     // Might be called from unmanaged thread.
 #ifndef _CPU_X86_64_
     *ip = (uintptr_t)cursor->stackframe.AddrPC.Offset;
@@ -504,7 +478,7 @@ static int jl_unw_step(bt_cursor_t *cursor, uintptr_t *ip, uintptr_t *sp, int lo
     }
 
     BOOL result = StackWalk64(IMAGE_FILE_MACHINE_I386, GetCurrentProcess(), hMainThread,
-        &cursor->stackframe, &cursor->context, NULL, JuliaFunctionTableAccess64, GetModuleBase64, NULL);
+        &cursor->stackframe, &cursor->context, NULL, JuliaFunctionTableAccess64, JuliaGetModuleBase64, NULL);
     return result;
 #else
     *ip = (uintptr_t)cursor->Rip;
@@ -517,20 +491,15 @@ static int jl_unw_step(bt_cursor_t *cursor, uintptr_t *ip, uintptr_t *sp, int lo
         return cursor->Rip != 0;
     }
 
-    DWORD64 ImageBase = GetModuleBase64(GetCurrentProcess(), cursor->Rip);
+    DWORD64 ImageBase = JuliaGetModuleBase64(GetCurrentProcess(), cursor->Rip);
     if (!ImageBase)
         return 0;
 
     PRUNTIME_FUNCTION FunctionEntry = (PRUNTIME_FUNCTION)JuliaFunctionTableAccess64(
         GetCurrentProcess(), cursor->Rip);
-    if (!FunctionEntry) { // assume this is a NO_FPO RBP-based function
-        cursor->Rsp = cursor->Rbp;                 // MOV RSP, RBP
-        if (!readable_pointer((LPCVOID)cursor->Rsp))
-            return 0;
-        cursor->Rbp = *(DWORD64*)cursor->Rsp;      // POP RBP
-        cursor->Rsp += sizeof(void*);
-        cursor->Rip = *(DWORD64*)cursor->Rsp;      // POP RIP (aka RET)
-        cursor->Rsp += sizeof(void*);
+    if (!FunctionEntry) {
+        // Not code or bad unwind?
+        return 0;
     }
     else {
         PVOID HandlerData;
@@ -552,12 +521,12 @@ static int jl_unw_step(bt_cursor_t *cursor, uintptr_t *ip, uintptr_t *sp, int lo
 #elif !defined(JL_DISABLE_LIBUNWIND)
 // stacktrace using libunwind
 
-static int jl_unw_init(bt_cursor_t *cursor, bt_context_t *context, int lockless)
+static int jl_unw_init(bt_cursor_t *cursor, bt_context_t *context)
 {
     return unw_init_local(cursor, context) == 0;
 }
 
-static int jl_unw_step(bt_cursor_t *cursor, uintptr_t *ip, uintptr_t *sp, int lockless)
+static int jl_unw_step(bt_cursor_t *cursor, uintptr_t *ip, uintptr_t *sp)
 {
     unw_word_t reg;
     if (unw_get_reg(cursor, UNW_REG_IP, &reg) < 0)
@@ -577,7 +546,7 @@ NOINLINE size_t rec_backtrace_ctx_dwarf(jl_bt_element_t *bt_data, size_t maxsize
     bt_cursor_t cursor;
     if (unw_init_local_dwarf(&cursor, context) != UNW_ESUCCESS)
         return 0;
-    jl_unw_stepn(&cursor, bt_data, &bt_size, NULL, maxsize, 0, &pgcstack, 1, 0);
+    jl_unw_stepn(&cursor, bt_data, &bt_size, NULL, maxsize, 0, &pgcstack, 1);
     return bt_size;
 }
 #endif
@@ -589,7 +558,7 @@ static int jl_unw_init(bt_cursor_t *cursor, bt_context_t *context)
     return 0;
 }
 
-static int jl_unw_step(bt_cursor_t *cursor, uintptr_t *ip, uintptr_t *sp, int lockless)
+static int jl_unw_step(bt_cursor_t *cursor, uintptr_t *ip, uintptr_t *sp)
 {
     return 0;
 }
diff --git a/src/staticdata.c b/src/staticdata.c
index 440926d0876a7..b15fec248e09a 100644
--- a/src/staticdata.c
+++ b/src/staticdata.c
@@ -166,9 +166,9 @@ typedef enum {
 } jl_callingconv_t;
 
 
-// this supports up to 1 GB images and 16 RefTags
+// this supports up to 8 RefTags, 512MB of pointer data, and 4/2 (64/32-bit) GB of constant data.
 // if a larger size is required, will need to add support for writing larger relocations in many cases below
-#define RELOC_TAG_OFFSET 28
+#define RELOC_TAG_OFFSET 29
 
 
 /* read and write in host byte order */
@@ -1394,6 +1394,12 @@ static void jl_save_system_image_to_stream(ios_t *f)
         jl_write_gv_ints(&s);
     }
 
+    if (sysimg.size > ((uintptr_t)1 << RELOC_TAG_OFFSET) ||
+        const_data.size > ((uintptr_t)1 << RELOC_TAG_OFFSET)*sizeof(void*)) {
+        jl_printf(JL_STDERR, "ERROR: system image too large\n");
+        jl_exit(1);
+    }
+
     // step 3: combine all of the sections into one file
     write_uint32(f, sysimg.size - sizeof(uint32_t));
     ios_seek(&sysimg, sizeof(uint32_t));
diff --git a/src/task.c b/src/task.c
index 9d88306dd4eee..06e6d4895e7d7 100644
--- a/src/task.c
+++ b/src/task.c
@@ -52,9 +52,7 @@ static inline void sanitizer_start_switch_fiber(const void* bottom, size_t size)
 static inline void sanitizer_finish_switch_fiber(void) {}
 #endif
 
-#if defined(_OS_WINDOWS_)
-volatile int jl_in_stackwalk = 0;
-#else
+#if !defined(_OS_WINDOWS_)
 #ifdef JL_HAVE_UCONTEXT
 #include <ucontext.h>
 #endif
diff --git a/stdlib/Pkg.version b/stdlib/Pkg.version
index f80c75c33cefa..8136ba368449b 100644
--- a/stdlib/Pkg.version
+++ b/stdlib/Pkg.version
@@ -1,2 +1,2 @@
 PKG_BRANCH = master
-PKG_SHA1 = 1542f285243b8ac31e666dee3c6690bdaf26a0be
+PKG_SHA1 = 0c3ccb119efd8b3182c114599abe78bc4f89dd4c
diff --git a/stdlib/Profile/test/runtests.jl b/stdlib/Profile/test/runtests.jl
index 8ff9fa9c76005..007492745ca47 100644
--- a/stdlib/Profile/test/runtests.jl
+++ b/stdlib/Profile/test/runtests.jl
@@ -111,3 +111,25 @@ end
     end
     @test getline(values(fdictc)) == getline(values(fdict0)) + 2
 end
+
+# Profile deadlocking in compilation (debuginfo registration)
+let cmd = Base.julia_cmd()
+    script = """
+        using Profile
+        f(::Val) = GC.safepoint()
+        @profile for i = 1:10^3; f(Val(i)); end
+        print(Profile.len_data())
+        """
+    p = open(`$cmd -e $script`)
+    t = Timer(120) do t
+        # should be under 10 seconds, so give it 2 minutes then report failure
+        println("KILLING BY PROFILE TEST WATCHDOG\n")
+        kill(p, Base.SIGTERM)
+        sleep(10)
+        kill(p, Base.SIGKILL)
+    end
+    s = read(p, String)
+    close(t)
+    @test success(p)
+    @test parse(Int, s) > 1000
+end
diff --git a/test/compiler/inference.jl b/test/compiler/inference.jl
index 4fd9a020252b9..226196fa74a49 100644
--- a/test/compiler/inference.jl
+++ b/test/compiler/inference.jl
@@ -2562,47 +2562,6 @@ end
 
 @test map(>:, [Int], [Int]) == [true]
 
-# issue 35566
-module Issue35566
-function step(acc, x)
-    xs, = acc
-    y = x > 0.0 ? x : missing
-    if y isa eltype(xs)
-        ys = push!(xs, y)
-    else
-        ys = vcat(xs, [y])
-    end
-    return (ys,)
-end
-
-function probe(y)
-    if y isa Tuple{Vector{Missing}}
-        return Val(:missing)
-    else
-        return Val(:expected)
-    end
-end
-
-function _foldl_iter(rf, val::T, iter, state) where {T}
-    while true
-        ret = iterate(iter, state)
-        ret === nothing && break
-        x, state = ret
-        y = rf(val, x)
-        if y isa T
-            val = y
-        else
-            return probe(y)
-        end
-    end
-    return Val(:expected)
-end
-
-f() = _foldl_iter(step, (Missing[],), [0.0], 1)
-end
-@test Core.Compiler.typesubtract(Tuple{Union{Int,Char}}, Tuple{Char}) == Tuple{Int}
-@test Base.return_types(Issue35566.f) == [Val{:expected}]
-
 # constant prop through keyword arguments
 _unstable_kw(;x=1,y=2) = x == 1 ? 0 : ""
 _use_unstable_kw_1() = _unstable_kw(x = 2)
@@ -2647,3 +2606,6 @@ for badf in [getfield_const_typename_bad1, getfield_const_typename_bad2]
     @test code[end] == Expr(:unreachable)
     @test_throws TypeError badf()
 end
+
+# issue #37638
+@test !(Core.Compiler.return_type(() -> (nothing, Any[]...)[2], Tuple{}) <: Vararg)
diff --git a/test/file.jl b/test/file.jl
index 3a7b4710281b5..27e60dd0c5ddf 100644
--- a/test/file.jl
+++ b/test/file.jl
@@ -268,6 +268,20 @@ no_error_logging(f::Function) =
     end
 end
 
+@testset "mktempdir() permissions correction" begin
+    # Test that `mktempdir()` with children with weird permissions get cleared
+    # before we would delete the directory
+    local temp_dir_path
+    mktempdir() do dir
+        temp_dir_path = dir
+        mkdir(joinpath(dir, "foo"))
+        touch(joinpath(dir, "foo", "bar"))
+        chmod(joinpath(dir, "foo"), 0o444)
+        @test isdir(temp_dir_path)
+    end
+    @test !isdir(temp_dir_path)
+end
+
 #######################################################################
 # This section tests some of the features of the stat-based file info #
 #######################################################################
diff --git a/test/show.jl b/test/show.jl
index 4e944633c29a8..1e173b5c64fee 100644
--- a/test/show.jl
+++ b/test/show.jl
@@ -1329,6 +1329,39 @@ end
 
 @test static_shown(QuoteNode(:x)) == ":(:x)"
 
+# PR #38049
+@test static_shown(sum) == "Base.sum"
+@test static_shown(+) == "Base.:(+)"
+@test static_shown(typeof(+)) == "typeof(Base.:(+))"
+
+struct var"#X#" end
+var"#f#"() = 2
+struct var"%X%" end  # Invalid name without '#'
+
+# (Just to make this test more sustainable,) we don't necesssarily need to test the exact
+# output format, just ensure that it prints at least the parts we expect:
+@test occursin(".var\"#X#\"", static_shown(var"#X#"))  # Leading `.` tests it printed a module name.
+@test occursin(r"Set{var\"[^\"]+\"} where var\"[^\"]+\"", static_shown(Set{<:Any}))
+
+# Test that static_shown is returning valid, correct julia expressions
+@testset "static_show() prints valid julia" begin
+    @testset for v in (
+            var"#X#",
+            var"#X#"(),
+            var"%X%",
+            var"%X%"(),
+            Vector,
+            Vector{<:Any},
+            Vector{var"#X#"},
+            +,
+            typeof(+),
+            var"#f#",
+            typeof(var"#f#"),
+        )
+        @test v == eval(Meta.parse(static_shown(v)))
+    end
+end
+
 # Test @show
 let fname = tempname()
     try
@@ -1986,3 +2019,12 @@ end
     @test sprint(show, skipmissing([1,2,missing])) == "skipmissing(Union{Missing, $Int}[1, 2, missing])"
     @test sprint(show, skipmissing((missing,1.0,'a'))) == "skipmissing((missing, 1.0, 'a'))"
 end
+
+@testset "unicode in method table" begin
+    αsym = gensym(:α)
+    ℓsym = gensym(:ℓ)
+    eval(:(foo($αsym) = $αsym))
+    eval(:(bar($ℓsym) = $ℓsym))
+    @test contains(string(methods(foo)), "foo(α)")
+    @test contains(string(methods(bar)), "bar(ℓ)")
+end