runtime: handle traps on Windows x32. (#1740)

crates/jit/src/unwind.rs

@@ -2,6 +2,9 @@ cfg_if::cfg_if! {
     if #[cfg(all(windows, target_arch = "x86_64"))] {
         mod winx64;
         pub use self::winx64::*;
+    } else if #[cfg(all(windows, target_arch = "x86"))] {
+        mod winx32;
+        pub use self::winx32::*;
     } else if #[cfg(unix)] {
         mod systemv;
         pub use self::systemv::*;

crates/jit/src/unwind/winx32.rs

@@ -0,0 +1,20 @@
+//! Stub unwind registry for Windows x32.
+
+use anyhow::{bail, Result};
+use cranelift_codegen::isa::{unwind::UnwindInfo, TargetIsa};
+
+pub struct UnwindRegistry {}
+
+impl UnwindRegistry {
+    pub fn new(_base_address: usize) -> Self {
+        Self {}
+    }
+
+    pub fn register(&mut self, _func_start: u32, _func_len: u32, _info: &UnwindInfo) -> Result<()> {
+        bail!("winx32 has no unwind registry")
+    }
+
+    pub fn publish(&mut self, _isa: &dyn TargetIsa) -> Result<()> {
+        Ok(())
+    }
+}

crates/runtime/src/traphandlers.rs

@@ -224,10 +224,16 @@ cfg_if::cfg_if! {
                     Some(info) => info,
                     None => return EXCEPTION_CONTINUE_SEARCH,
                 };
-                let jmp_buf = info.handle_trap(
+                cfg_if::cfg_if! {
-                    (*(*exception_info).ContextRecord).Rip as *const u8,
+                    if #[cfg(target_arch = "x86_64")] {
-                    |handler| handler(exception_info),
+                        let ip = (*(*exception_info).ContextRecord).Rip as *const u8;
-                );
+                    } else if #[cfg(target_arch = "x86")] {
+                        let ip = (*(*exception_info).ContextRecord).Eip as *const u8;
+                    } else {
+                        compile_error!("unsupported platform");
+                    }
+                }
+                let jmp_buf = info.handle_trap(ip, |handler| handler(exception_info));
                 if jmp_buf.is_null() {
                     EXCEPTION_CONTINUE_SEARCH
                 } else if jmp_buf as usize == 1 {