Add a helper to set register values

This helper additionally simplifies constants.  This is very useful for dealing
with simplifying the instruction pointer.  That is required by the rest of
macaw, which expects IP values it wants to explore to be fully reduced.

macaw-ppc/src/Data/Macaw/PPC/Disassemble.hs

@@ -112,7 +112,7 @@ disassembleBlock lookupSemantics mem gs curIPAddr maxOffset = do
 
             nextIPExpr <- getRegValue PPC_IP
             case matchConditionalBranch nextIPExpr of
-              Just (cond, t_ip, f_ip) -> conditionalBranch cond (setIP t_ip) (setIP f_ip)
+              Just (cond, t_ip, f_ip) -> conditionalBranch cond (setRegVal PPC_IP t_ip) (setRegVal PPC_IP f_ip)
               Nothing -> return ())
           case egs1 of
             Left genErr -> failAt gs off curIPAddr (GenerationError i genErr)

macaw-ppc/src/Data/Macaw/PPC/Generator.hs

@@ -35,7 +35,7 @@ module Data.Macaw.PPC.Generator (
   addExpr,
   bvconcat,
   bvselect,
-  setIP,
+  setRegVal,
   -- * Lenses
   blockState,
   curPPCState,
@@ -189,8 +189,12 @@ curPPCState = blockState . pBlockState
 ------------------------------------------------------------------------
 -- Factored-out Operations for PPCGenerator
 
-setIP :: (PPCArchConstraints ppc, RegAddrWidth (PPCReg ppc) ~ w) => Value ppc ids (BVType w) -> PPCGenerator ppc ids s ()
-setIP val = curPPCState . boundValue PPC_IP .= val
+setRegVal :: (PPCArchConstraints ppc, RegAddrWidth (PPCReg ppc) ~ w)
+          => PPCReg ppc tp
+          -> Value ppc ids tp
+          -> PPCGenerator ppc ids s ()
+setRegVal reg val =
+  curPPCState . boundValue reg .= fromMaybe val (simplifyValue val)
 
 -- | The implementation of bitvector concatenation
 --

macaw-ppc/src/Data/Macaw/PPC/Semantics/TH.hs

@@ -19,7 +19,7 @@ module Data.Macaw.PPC.Semantics.TH
 import qualified Data.ByteString as BS
 import qualified Data.Constraint as C
 
-import           Control.Lens ( (.=), (^.) )
+import           Control.Lens ( (^.) )
 import           Data.Proxy ( Proxy(..) )
 import qualified Data.List as L
 import qualified Data.Text as T
@@ -313,12 +313,12 @@ translateFormula ipVarName semantics interps varNames = do
               let FreeParamF name = varNames `SL.indexShapedList` idx
               [| do val <- $(addEltTH interps expr)
                     let reg = toPPCReg $(varE name)
-                    curPPCState . M.boundValue reg .= val
+                    setRegVal reg val
                |]
             LiteralParameter APPC.LocMem -> writeMemTH interps expr
             LiteralParameter loc -> do
               [| do val <- $(addEltTH interps expr)
-                    curPPCState . M.boundValue $(locToRegTH (Proxy @arch) loc) .= val
+                    setRegVal $(locToRegTH (Proxy @arch) loc) val
                |]
             FunctionParameter str (WrappedOperand _ opIx) _w -> do
               let FreeParamF boundOperandName = SL.indexShapedList varNames opIx
@@ -328,7 +328,7 @@ translateFormula ipVarName semantics interps varNames = do
                   [| do case $(varE (A.exprInterpName fi)) $(varE boundOperandName) of
                           Just reg -> do
                             val <- $(addEltTH interps expr)
-                            curPPCState . M.boundValue (toPPCReg reg) .= val
+                            setRegVal (toPPCReg reg) val
                           Nothing -> error ("Invalid instruction form at " ++ show $(varE ipVarName))
                    |]