Merge pull request #2615 from alexcrichton/precise-pc-trap

Only handle signals at pcs with trap information

crates/runtime/src/traphandlers.rs

@@ -432,7 +432,7 @@ pub unsafe trait TrapInfo {
 
     /// Returns whether the given program counter lies within wasm code,
     /// indicating whether we should handle a trap or not.
-    fn is_wasm_code(&self, pc: usize) -> bool;
+    fn is_wasm_trap(&self, pc: usize) -> bool;
 
     /// Uses `call` to call a custom signal handler, if one is specified.
     ///
@@ -635,7 +635,7 @@ impl<'a> CallThreadState<'a> {
         }
 
         // If this fault wasn't in wasm code, then it's not our problem
-        if !self.trap_info.is_wasm_code(pc as usize) {
+        if !self.trap_info.is_wasm_trap(pc as usize) {
             return ptr::null();
         }
 

crates/wasmtime/src/store.rs

@@ -191,8 +191,9 @@ impl Store {
             None => return,
         };
         // Only register this module if it hasn't already been registered.
-        if !self.is_wasm_code(first_pc) {
-            self.inner.frame_info.borrow_mut().register(module);
+        let mut info = self.inner.frame_info.borrow_mut();
+        if !info.contains_pc(first_pc) {
+            info.register(module);
         }
     }
 
@@ -400,8 +401,8 @@ unsafe impl TrapInfo for Store {
         self
     }
 
-    fn is_wasm_code(&self, addr: usize) -> bool {
-        self.frame_info().borrow().contains_pc(addr)
+    fn is_wasm_trap(&self, addr: usize) -> bool {
+        self.frame_info().borrow().lookup_trap_info(addr).is_some()
     }
 
     fn custom_signal_handler(&self, call: &dyn Fn(&SignalHandler) -> bool) -> bool {