From 3bef2b9cdb6aa22c40e010015003be3a340d8eca Mon Sep 17 00:00:00 2001
From: Zachary Snow <zach@zachjs.com>
Date: Fri, 10 May 2019 10:41:31 -0400
Subject: [PATCH] struct conversion handles alternate and mixed integer vector
 field types

---
 src/Convert/IntTypes.hs     |  3 ++-
 src/Convert/Struct.hs       | 28 ++++++++++------------------
 test/basic/struct_shadow.sv | 12 ++++++------
 3 files changed, 18 insertions(+), 25 deletions(-)

diff --git a/src/Convert/IntTypes.hs b/src/Convert/IntTypes.hs
index 3ada549..58a31eb 100644
--- a/src/Convert/IntTypes.hs
+++ b/src/Convert/IntTypes.hs
@@ -1,7 +1,7 @@
 {- sv2v
  - Author: Zachary Snow <zach@zachjs.com>
  -
- - Conversion for `int`, `shortint`, `longint`, and `byte`
+ - Conversion for `bit`, `int`, `shortint`, `longint`, and `byte`
  -}
 
 module Convert.IntTypes (convert) where
@@ -21,6 +21,7 @@ convertType (IntegerAtom TInt      sg) = baseType sg Signed      32
 convertType (IntegerAtom TShortint sg) = baseType sg Signed      16
 convertType (IntegerAtom TLongint  sg) = baseType sg Signed      64
 convertType (IntegerAtom TByte     sg) = baseType sg Unspecified  8
+convertType (IntegerVector TBit sg rs) = IntegerVector TLogic sg rs
 convertType other = other
 
 -- makes a integer "compatible" type with the given signing, base signing and
diff --git a/src/Convert/Struct.hs b/src/Convert/Struct.hs
index 6c9629d..2c85023 100644
--- a/src/Convert/Struct.hs
+++ b/src/Convert/Struct.hs
@@ -71,8 +71,6 @@ convertDescription other = other
 -- write down unstructured versions of packed struct types
 collectStructM :: Type -> Writer Structs ()
 collectStructM (Struct (Packed sg) fields _) = do
-    -- TODO: How should we combine the structs Signing with that of the types it
-    -- contains?
     if canUnstructure
         then tell $ Map.singleton
             (Struct (Packed sg) fields)
@@ -102,25 +100,19 @@ collectStructM (Struct (Packed sg) fields _) = do
         vals = zip unstructRanges unstructOffsets
         unstructFields = Map.fromList $ zip keys vals
 
-        -- create the unstructured type
-        tf = fst $ typeRanges $ head fieldTypes
+        -- create the unstructured type; result type takes on the signing of the
+        -- struct itself to preserve behavior of operations on the whole struct
         structSize = foldl1 (BinOp Add) fieldSizes
         packedRange = (simplify $ BinOp Sub structSize (Number "1"), zero)
-        unstructType = tf [packedRange]
+        unstructType = IntegerVector TLogic sg [packedRange]
 
-        -- TODO: For now, we only convert packed structs which contain fields
-        -- with all the same base type. We might be able to get away with
-        -- converting everything to a Logic type. This should work in cases of
-        -- mixed `wire`/`logic` or `reg`/`logic`.
-        fieldClasses = map (show . fst . typeRanges) fieldTypes
-        isComplex :: Type -> Bool
-        isComplex (Struct _ _ _) = True
-        isComplex (Enum   _ _ _) = True
-        isComplex (Alias  _ _ _) = True
-        isComplex _ = False
-        canUnstructure =
-            all (head fieldClasses ==) fieldClasses &&
-            not (any isComplex fieldTypes)
+        -- check if this struct can be packed into an integer vector; integer
+        -- atoms and non-integers do not have a definitive size, and so cannot
+        -- be packed; net types are not permitted as struct fields
+        isIntVec :: Type -> Bool
+        isIntVec (IntegerVector _ _ _) = True
+        isIntVec _ = False
+        canUnstructure = all isIntVec fieldTypes
 
 collectStructM _ = return ()
 
diff --git a/test/basic/struct_shadow.sv b/test/basic/struct_shadow.sv
index d5e88c5..82c141e 100644
--- a/test/basic/struct_shadow.sv
+++ b/test/basic/struct_shadow.sv
@@ -1,9 +1,9 @@
-typedef struct packed { logic w, x, y; } StructA;
-typedef struct packed { logic w, y, x; } StructB;
-typedef struct packed { logic x, w, y; } StructC;
-typedef struct packed { logic y, w, x; } StructD;
-typedef struct packed { logic x, y, w; } StructE;
-typedef struct packed { logic y, x, w; } StructF;
+typedef struct packed { reg w; bit x; logic y; } StructA;
+typedef struct packed { reg w; logic y; bit x; } StructB;
+typedef struct packed { bit x; reg w; logic y; } StructC;
+typedef struct packed { logic y; reg w; bit x; } StructD;
+typedef struct packed { bit x; logic y; reg w; } StructE;
+typedef struct packed { logic y; bit x; reg w; } StructF;
 
 module top;