diff --git a/src/librustc_target/spec/i686_unknown_windows_gnu.rs b/src/librustc_target/spec/i686_unknown_windows_gnu.rs
new file mode 100644
index 0000000000000..dfe12626af21b
--- /dev/null
+++ b/src/librustc_target/spec/i686_unknown_windows_gnu.rs
@@ -0,0 +1,27 @@
+use crate::spec::{LinkerFlavor, Target, TargetResult};
+
+pub fn target() -> TargetResult {
+    let mut base = super::windows_base::opts();
+    base.cpu = "pentium4".to_string();
+    base.max_atomic_width = Some(64);
+    base.eliminate_frame_pointer = false; // Required for backtraces
+
+    // Mark all dynamic libraries and executables as compatible with the larger 4GiB address
+    // space available to x86 Windows binaries on x86_64.
+    base.pre_link_args
+        .get_mut(&LinkerFlavor::Gcc).unwrap().push("-Wl,--large-address-aware".to_string());
+
+    Ok(Target {
+        llvm_target: "i686-unknown-windows-gnu".to_string(),
+        target_endian: "little".to_string(),
+        target_pointer_width: "32".to_string(),
+        target_c_int_width: "32".to_string(),
+        data_layout: "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32".to_string(),
+        arch: "x86".to_string(),
+        target_os: "windows".to_string(),
+        target_env: "gnu".to_string(),
+        target_vendor: "unknown".to_string(),
+        linker_flavor: LinkerFlavor::Gcc,
+        options: base,
+    })
+}
diff --git a/src/librustc_target/spec/mod.rs b/src/librustc_target/spec/mod.rs
index 3054ffabb4f1f..3f763cc70eb70 100644
--- a/src/librustc_target/spec/mod.rs
+++ b/src/librustc_target/spec/mod.rs
@@ -433,6 +433,7 @@ supported_targets! {
 
     ("x86_64-pc-windows-gnu", x86_64_pc_windows_gnu),
     ("i686-pc-windows-gnu", i686_pc_windows_gnu),
+    ("i686-unknown-windows-gnu", i686_unknown_windows_gnu),
 
     ("aarch64-pc-windows-msvc", aarch64_pc_windows_msvc),
     ("x86_64-pc-windows-msvc", x86_64_pc_windows_msvc),
diff --git a/src/libunwind/libunwind.rs b/src/libunwind/libunwind.rs
index 30897970fa220..00f9115107359 100644
--- a/src/libunwind/libunwind.rs
+++ b/src/libunwind/libunwind.rs
@@ -72,7 +72,6 @@ pub type _Unwind_Exception_Cleanup_Fn = extern "C" fn(unwind_code: _Unwind_Reaso
            link(name = "unwind", kind = "static"))]
 extern "C" {
     #[unwind(allowed)]
-    pub fn _Unwind_Resume(exception: *mut _Unwind_Exception) -> !;
     pub fn _Unwind_DeleteException(exception: *mut _Unwind_Exception);
     pub fn _Unwind_GetLanguageSpecificData(ctx: *mut _Unwind_Context) -> *mut c_void;
     pub fn _Unwind_GetRegionStart(ctx: *mut _Unwind_Context) -> _Unwind_Ptr;
@@ -212,32 +211,55 @@ if #[cfg(all(any(target_os = "ios", target_os = "netbsd", not(target_arch = "arm
 }
 } // cfg_if!
 
-cfg_if::cfg_if! {
-if #[cfg(not(all(target_os = "ios", target_arch = "arm")))] {
-    // Not 32-bit iOS
+pub mod dwarf2 {
+    use crate::{_Unwind_Exception, _Unwind_Reason_Code, _Unwind_Trace_Fn};
+    use libc::c_void;
     #[cfg_attr(all(not(bootstrap), feature = "llvm-libunwind",
                    any(target_os = "fuchsia", target_os = "linux")),
                link(name = "unwind", kind = "static"))]
     extern "C" {
         #[unwind(allowed)]
+        pub fn _Unwind_Resume(exception: *mut _Unwind_Exception) -> !;
         pub fn _Unwind_RaiseException(exception: *mut _Unwind_Exception) -> _Unwind_Reason_Code;
-        pub fn _Unwind_Backtrace(trace: _Unwind_Trace_Fn,
-                                 trace_argument: *mut c_void)
-                                 -> _Unwind_Reason_Code;
+        pub fn _Unwind_Backtrace(trace: _Unwind_Trace_Fn, trace_argument: *mut c_void)
+            -> _Unwind_Reason_Code;
     }
-} else {
-    // 32-bit iOS uses SjLj and does not provide _Unwind_Backtrace()
+}
+
+pub mod sjlj {
+    use crate::{_Unwind_Exception, _Unwind_Reason_Code};
     #[cfg_attr(all(not(bootstrap), feature = "llvm-libunwind",
                    any(target_os = "fuchsia", target_os = "linux")),
                link(name = "unwind", kind = "static"))]
     extern "C" {
         #[unwind(allowed)]
-        pub fn _Unwind_SjLj_RaiseException(e: *mut _Unwind_Exception) -> _Unwind_Reason_Code;
+        pub fn _Unwind_Sjlj_Resume(exception: *mut _Unwind_Exception) -> !;
+        pub fn _Unwind_Sjlj_RaiseException(exception: *mut _Unwind_Exception)
+            -> _Unwind_Reason_Code;
+    }
+    #[inline]
+    pub unsafe fn _Unwind_Resume(exception: *mut _Unwind_Exception) -> ! {
+        _Unwind_Sjlj_Resume(exception)
     }
-
     #[inline]
-    pub unsafe fn _Unwind_RaiseException(exc: *mut _Unwind_Exception) -> _Unwind_Reason_Code {
-        _Unwind_SjLj_RaiseException(exc)
+    pub unsafe fn _Unwind_RaiseException(exception: *mut _Unwind_Exception) -> _Unwind_Reason_Code {
+        _Unwind_Sjlj_RaiseException(exception)
     }
 }
+
+cfg_if::cfg_if! {
+    // 32-bit iOS
+    if #[cfg(all(target_os = "ios", target_arch = "arm"))] {
+        pub use sjlj::*;
+    }
+    // FIXME: i686-unknown-windows-gnu target with sjlj
+    else if #[cfg(all(target_vendor = "unknown",
+                      target_os = "windows",
+                      target_arch = "x86",
+                      target_env = "gnu"))] {
+        pub use sjlj::*;
+    }
+    else {
+        pub use dwarf2::*;
+    }
 } // cfg_if!