[sledge] Check type of arg of Resume the same as param of LandingPad

Summary:
Not all types of exceptions allowed by LLVM are currently
supported. The types of Resume args and LandingPad params must be
compatible, and so it only makes sense to check they the same
way.

Reviewed By: jvillard

Differential Revision: D27188307

fbshipit-source-id: c88cc46d0

sledge/cli/frontend.ml

@@ -850,12 +850,7 @@ let pop_stack_frame_of_function :
   in
   pop
 
-(** construct the types involved in landingpads: i32, std::type_info*, and
+let check_exception_typ x instr llt =
-    __cxa_exception *)
-let landingpad_typs : x -> Llvm.llvalue -> Typ.t * Typ.t * Llvm.lltype =
- fun x instr ->
-  let llt = Llvm.type_of instr in
-  let i32 = i32 x in
   if
     not
       ( Poly.(Llvm.classify_type llt = Struct)
@@ -865,7 +860,14 @@ let landingpad_typs : x -> Llvm.llvalue -> Typ.t * Typ.t * Llvm.lltype =
       && Poly.(llelts.(0) = Llvm.pointer_type (Llvm.i8_type x.llcontext))
       && Poly.(llelts.(1) = Llvm.i32_type x.llcontext) )
   then
-    todo "landingpad of type other than {i8*, i32}: %a" pp_llvalue instr () ;
+    todo "exception of type other than {i8*, i32}: %a" pp_llvalue instr ()
+
+(** construct the types involved in landingpads: i32, std::type_info*, and
+    __cxa_exception *)
+let landingpad_typs : x -> Llvm.llvalue -> Typ.t * Typ.t * Llvm.lltype =
+ fun x instr ->
+  check_exception_typ x instr (Llvm.type_of instr) ;
+  let i32 = i32 x in
   let llcontext =
     Llvm.(
       module_context (global_parent (block_parent (instr_parent instr))))
@@ -1424,7 +1426,9 @@ let xlate_instr :
               [Block.mk ~lbl ~cmnd:(IArray.of_list insts) ~term] ) )
   | Resume ->
       let llrcd = Llvm.operand instr 0 in
-      let typ = xlate_type x (Llvm.type_of llrcd) in
+      let lltyp = Llvm.type_of llrcd in
+      check_exception_typ x instr lltyp ;
+      let typ = xlate_type x lltyp in
       let pre, rcd = xlate_value x llrcd in
       let exc = Exp.select typ rcd 0 in
       emit_term ~prefix:(pop loc @ pre) (Term.throw ~exc ~loc)