crucible-llvm: Don't pass around the symbolic backend explicitly

`Lang.Crucible.Simulator.OverrideSim.{getSymInterface,ovrWithBackend}`
can replace the explicit passing of `bak`. This should simplify some
type signatures.

crucible-llvm/src/Lang/Crucible/LLVM/Intrinsics/LLVM.hs

@@ -739,7 +739,7 @@ llvmBSwapOverride widthRepr =
         -- From the LLVM docs:
         -- declare i16 @llvm.bswap.i16(i16 <id>)
         [llvmOvr| #width8 $nm( #width8 ) |]
-        (\_ bak args -> Ctx.uncurryAssignment (Libc.callBSwap bak widthRepr) args)
+        (\_ _bak args -> Ctx.uncurryAssignment (Libc.callBSwap widthRepr) args)
     }}}
 
 llvmAbsOverride ::

crucible-llvm/src/Lang/Crucible/LLVM/Intrinsics/Libc.hs

@@ -1529,7 +1529,7 @@ llvmHtonlOverride ::
       (BVType 32)
 llvmHtonlOverride =
   [llvmOvr| i32 @htonl( i32 ) |]
-  (\_ bak args -> Ctx.uncurryAssignment (callBSwapIfLittleEndian bak (knownNat @4)) args)
+  (\_ bak args -> Ctx.uncurryAssignment (callBSwapIfLittleEndian (knownNat @4)) args)
 
 llvmHtonsOverride ::
   (IsSymInterface sym, ?lc :: TypeContext) =>
@@ -1538,7 +1538,7 @@ llvmHtonsOverride ::
       (BVType 16)
 llvmHtonsOverride =
   [llvmOvr| i16 @htons( i16 ) |]
-  (\_ bak args -> Ctx.uncurryAssignment (callBSwapIfLittleEndian bak (knownNat @2)) args)
+  (\_ bak args -> Ctx.uncurryAssignment (callBSwapIfLittleEndian (knownNat @2)) args)
 
 llvmNtohlOverride ::
   (IsSymInterface sym, ?lc :: TypeContext) =>
@@ -1547,7 +1547,7 @@ llvmNtohlOverride ::
       (BVType 32)
 llvmNtohlOverride =
   [llvmOvr| i32 @ntohl( i32 ) |]
-  (\_ bak args -> Ctx.uncurryAssignment (callBSwapIfLittleEndian bak (knownNat @4)) args)
+  (\_ bak args -> Ctx.uncurryAssignment (callBSwapIfLittleEndian (knownNat @4)) args)
 
 llvmNtohsOverride ::
   (IsSymInterface sym, ?lc :: TypeContext) =>
@@ -1556,7 +1556,7 @@ llvmNtohsOverride ::
       (BVType 16)
 llvmNtohsOverride =
   [llvmOvr| i16 @ntohs( i16 ) |]
-  (\_ bak args -> Ctx.uncurryAssignment (callBSwapIfLittleEndian bak (knownNat @2)) args)
+  (\_ bak args -> Ctx.uncurryAssignment (callBSwapIfLittleEndian (knownNat @2)) args)
 
 llvmAbsOverride ::
   (IsSymInterface sym, HasLLVMAnn sym) =>
@@ -1606,13 +1606,13 @@ llvmLLAbsOverride =
         Ctx.uncurryAssignment (callLibcAbs bak callStack (knownNat @64)) args)
 
 callBSwap ::
-  (1 <= width, IsSymBackend sym bak) =>
-  bak ->
+  (1 <= width, IsSymInterface sym) =>
   NatRepr width ->
   RegEntry sym (BVType (width * 8)) ->
   OverrideSim p sym ext r args ret (RegValue sym (BVType (width * 8)))
-callBSwap bak widthRepr (regValue -> vec) =
-  liftIO $ bvSwap (backendGetSym bak) widthRepr vec
+callBSwap widthRepr (regValue -> vec) = do
+  sym <- getSymInterface
+  liftIO $ bvSwap sym widthRepr vec
 
 -- | This determines under what circumstances @callAbs@ should check if its
 -- argument is equal to the smallest signed integer of a particular size
@@ -1699,15 +1699,14 @@ callLLVMAbs bak callStack widthRepr src (regValue -> isIntMinPoison) = do
 -- Otherwise, return the input unchanged. This is the workhorse for the
 -- @hton{s,l}@ and @ntoh{s,l}@ overrides.
 callBSwapIfLittleEndian ::
-  (1 <= width, IsSymBackend sym bak, ?lc :: TypeContext) =>
-  bak ->
+  (1 <= width, IsSymInterface sym, ?lc :: TypeContext) =>
   NatRepr width ->
   RegEntry sym (BVType (width * 8)) ->
   OverrideSim p sym ext r args ret (RegValue sym (BVType (width * 8)))
-callBSwapIfLittleEndian bak widthRepr vec =
+callBSwapIfLittleEndian widthRepr vec =
   case (llvmDataLayout ?lc)^.intLayout of
     BigEndian    -> pure (regValue vec)
-    LittleEndian -> callBSwap bak widthRepr vec
+    LittleEndian -> callBSwap widthRepr vec
 
 ----------------------------------------------------------------------------
 -- atexit stuff