From 1aa30ea8139c3f5cfc9d24983437ee051b1871e6 Mon Sep 17 00:00:00 2001
From: Zachary Snow <zach@zachjs.com>
Date: Tue, 27 Jul 2021 19:17:03 -0400
Subject: [PATCH] allow genvars to be shadowed

---
 src/Convert/DuplicateGenvar.hs       |  2 +-
 src/Convert/Scoper.hs                | 14 +++++++++++++-
 src/Convert/TypeOf.hs                | 24 +++++++++++++++---------
 test/core/duplicate_genvar_shadow.sv | 26 ++++++++++++++++++++++++++
 test/core/duplicate_genvar_shadow.v  |  9 +++++++++
 5 files changed, 64 insertions(+), 11 deletions(-)
 create mode 100644 test/core/duplicate_genvar_shadow.sv
 create mode 100644 test/core/duplicate_genvar_shadow.v

diff --git a/src/Convert/DuplicateGenvar.hs b/src/Convert/DuplicateGenvar.hs
index fae44d5..46b3dff 100644
--- a/src/Convert/DuplicateGenvar.hs
+++ b/src/Convert/DuplicateGenvar.hs
@@ -18,7 +18,7 @@ traverseDescription = partScoper return traverseModuleItemM return return
 
 traverseModuleItemM :: ModuleItem -> Scoper () ModuleItem
 traverseModuleItemM (Genvar x) = do
-    details <- lookupElemM x
+    details <- lookupLocalIdentM x
     if details == Nothing
         then insertElem x () >> return (Genvar x)
         else return $ Generate []
diff --git a/src/Convert/Scoper.hs b/src/Convert/Scoper.hs
index fbdf9f2..28fd59e 100644
--- a/src/Convert/Scoper.hs
+++ b/src/Convert/Scoper.hs
@@ -56,6 +56,8 @@ module Convert.Scoper
     , procedureLocM
     , isLoopVar
     , isLoopVarM
+    , loopVarDepth
+    , loopVarDepthM
     , lookupLocalIdent
     , lookupLocalIdentM
     , scopeModuleItemT
@@ -65,7 +67,7 @@ module Convert.Scoper
 
 import Control.Monad.State.Strict
 import Data.Functor.Identity (runIdentity)
-import Data.List (partition)
+import Data.List (findIndices, partition)
 import Data.Maybe (isNothing)
 import qualified Data.Map.Strict as Map
 
@@ -357,6 +359,16 @@ isLoopVar scopes x = any matches $ sCurrent scopes
 isLoopVarM :: Monad m => Identifier -> ScoperT a m Bool
 isLoopVarM = embedScopes isLoopVar
 
+loopVarDepth :: Scopes a -> Identifier -> Maybe Int
+loopVarDepth scopes x =
+    case findIndices matches $ sCurrent scopes of
+        [] -> Nothing
+        indices -> Just $ last indices
+    where matches = (== x) . tierIndex
+
+loopVarDepthM :: Monad m => Identifier -> ScoperT a m (Maybe Int)
+loopVarDepthM = embedScopes loopVarDepth
+
 evalScoper
     :: MapperM (Scoper a) Decl
     -> MapperM (Scoper a) ModuleItem
diff --git a/src/Convert/TypeOf.hs b/src/Convert/TypeOf.hs
index cd5c0c9..b75a398 100644
--- a/src/Convert/TypeOf.hs
+++ b/src/Convert/TypeOf.hs
@@ -157,18 +157,24 @@ traverseTypeM other =
 -- attempts to find the given (potentially hierarchical or generate-scoped)
 -- expression in the available scope information
 lookupTypeOf :: Expr -> ST Type
+lookupTypeOf expr@(Ident x) = do
+    details <- lookupElemM x
+    loopVar <- loopVarDepthM x
+    return $ case details of
+        Nothing ->
+            if loopVar == Nothing
+                then TypeOf expr
+                else IntegerAtom TInteger Unspecified
+        Just (accesses, replacements, typ) ->
+            if maybe True (length accesses >) loopVar
+                then replaceInType replacements typ
+                else IntegerAtom TInteger Unspecified
 lookupTypeOf expr = do
     details <- lookupElemM expr
-    case details of
-        Nothing -> case expr of
-            Ident x -> do
-                isGenvar <- isLoopVarM x
-                return $ if isGenvar
-                    then IntegerAtom TInteger Unspecified
-                    else TypeOf expr
-            _ -> return $ TypeOf expr
+    return $ case details of
+        Nothing -> TypeOf expr
         Just (_, replacements, typ) ->
-            return $ replaceInType replacements typ
+            replaceInType replacements typ
 
 -- determines the type of an expression based on the available scope information
 -- according the semantics defined in IEEE 1800-2017, especially Section 11.6
diff --git a/test/core/duplicate_genvar_shadow.sv b/test/core/duplicate_genvar_shadow.sv
new file mode 100644
index 0000000..d2f7051
--- /dev/null
+++ b/test/core/duplicate_genvar_shadow.sv
@@ -0,0 +1,26 @@
+`define DUMP(L) initial $display(`"L %0d`", $bits(i));
+module top;
+    genvar i;
+    for (i = 0; i < 1; i = 1) begin
+        `DUMP(A)
+        if (1) begin
+            localparam [9:0] i = 1;
+            `DUMP(B)
+            if (1) begin
+                genvar i;
+                for (i = 0; i < 1; i = 1) begin
+                    `DUMP(C)
+                    if (1) begin
+                        localparam [5:0] i = 1;
+                        `DUMP(D)
+                        if (1) begin
+                            genvar i;
+                            for (i = 0; i < 1; i = 1)
+                                `DUMP(E)
+                        end
+                    end
+                end
+            end
+        end
+    end
+endmodule
diff --git a/test/core/duplicate_genvar_shadow.v b/test/core/duplicate_genvar_shadow.v
new file mode 100644
index 0000000..780b2a6
--- /dev/null
+++ b/test/core/duplicate_genvar_shadow.v
@@ -0,0 +1,9 @@
+module top;
+    initial begin
+        $display("A %0d", 32);
+        $display("B %0d", 10);
+        $display("C %0d", 32);
+        $display("D %0d", 6);
+        $display("E %0d", 32);
+    end
+endmodule