From c49fad1dbad8fff7a1ded3db8552771c9e9a659d Mon Sep 17 00:00:00 2001
From: Zachary Snow <zach@zachjs.com>
Date: Sat, 29 Oct 2022 13:22:53 -0400
Subject: [PATCH] drop unneeded module-scoped references

---
 CHANGELOG.md                    |  1 +
 src/Convert/TypeOf.hs           | 20 ++++++++++++++++++++
 test/core/unneeded_scope.sv     | 16 ++++++++++++++++
 test/core/unneeded_scope.sv.pat |  5 +++++
 test/core/unneeded_scope.v      | 12 ++++++++++++
 test/lib/functions.sh           | 18 ++++++++++++++++++
 6 files changed, 72 insertions(+)
 create mode 100644 test/core/unneeded_scope.sv
 create mode 100644 test/core/unneeded_scope.sv.pat
 create mode 100644 test/core/unneeded_scope.v

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8d69d50..fc9fb90 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 * Fixed module-level localparams being needlessly inlined when forming longest
   static prefixes, which could cause deep recursion and run out of memory on
   some designs
+* Fixed unneeded scoping of constant function calls used in type lookups
 
 ### Other Enhancements
 
diff --git a/src/Convert/TypeOf.hs b/src/Convert/TypeOf.hs
index 54fbdd1..9ecbc2f 100644
--- a/src/Convert/TypeOf.hs
+++ b/src/Convert/TypeOf.hs
@@ -122,6 +122,11 @@ traverseExprM (Cast (Right size) expr) = do
     expr' <- traverseExprM expr
     size' <- traverseExprM size
     elaborateSizeCast size' expr'
+traverseExprM orig@(Dot (Ident x) f) = do
+    unneeded <- unneededModuleScope x f
+    return $ if unneeded
+        then Ident f
+        else orig
 traverseExprM other =
     traverseSinglyNestedExprsM traverseExprM other
     >>= traverseExprTypesM traverseTypeM
@@ -150,6 +155,21 @@ isStringParam (Ident x) = do
         Just (_, _, typ) -> typ == TypeOf (Ident x)
 isStringParam _ = return False
 
+-- checks if referring to part.wire is needlessly explicit
+unneededModuleScope :: Identifier -> Identifier -> ST Bool
+unneededModuleScope part wire = do
+    accessesLocal <- localAccessesM wire
+    if accessesLocal == accessesTop then
+        return True
+    else if head accessesLocal == head accessesTop then do
+        details <- lookupElemM wire
+        return $ case details of
+            Just (accessesFound, _, _) -> accessesTop == accessesFound
+            _ -> False
+    else
+        return False
+    where accessesTop = [Access part Nil, Access wire Nil]
+
 -- convert TypeOf in a Type
 traverseTypeM :: Type -> ST Type
 traverseTypeM (TypeOf expr) =
diff --git a/test/core/unneeded_scope.sv b/test/core/unneeded_scope.sv
new file mode 100644
index 0000000..04c21a3
--- /dev/null
+++ b/test/core/unneeded_scope.sv
@@ -0,0 +1,16 @@
+module top;
+    function automatic integer incr;
+        input integer inp;
+        return inp + 1;
+    endfunction
+    parameter P = 3;
+    logic [incr(P):0] x;
+    logic [$bits(x) * 2:0] y, z;
+    if (1) begin
+        assign top.y = {top.x, x};
+    end
+    if (1) begin : blk
+        wire x;
+        assign z = {blk.x, top.x};
+    end
+endmodule
diff --git a/test/core/unneeded_scope.sv.pat b/test/core/unneeded_scope.sv.pat
new file mode 100644
index 0000000..484e19a
--- /dev/null
+++ b/test/core/unneeded_scope.sv.pat
@@ -0,0 +1,5 @@
+affirm top.y
+affirm top.x
+affirm blk.x
+affirm incr
+reject top.incr
diff --git a/test/core/unneeded_scope.v b/test/core/unneeded_scope.v
new file mode 100644
index 0000000..a378add
--- /dev/null
+++ b/test/core/unneeded_scope.v
@@ -0,0 +1,12 @@
+module top;
+    parameter P = 3;
+    wire [P + 1:0] x;
+    wire [2 * P + 4:0] y, z;
+    assign y = {x, x};
+    generate
+        if (1) begin : blk
+            wire x;
+        end
+    endgenerate
+    assign z = {blk.x, x};
+endmodule
diff --git a/test/lib/functions.sh b/test/lib/functions.sh
index 0055b8d..804873f 100644
--- a/test/lib/functions.sh
+++ b/test/lib/functions.sh
@@ -45,6 +45,24 @@ assertConverts() {
     ac_tmpa=$SHUNIT_TMPDIR/ac-conv-tmpa.v
     convert "1st conversion of $ac_file" $ac_tmpa $ac_file
 
+    # check for un/expected output in the converted result
+    ac_pats=$ac_file.pat
+    if [ -f $ac_pats ]; then
+        while read line; do
+            rule=${line:0:6}
+            pattern=${line:7}
+            grep -G "$pattern" < $ac_tmpa > /dev/null
+            matches=$?
+            if [ $rule == "affirm" ]; then
+                assertTrue "conversion of $ac_file does not contain $pattern" $matches
+            elif [ $rule == "reject" ]; then
+                assertFalse "conversion of $ac_file contains $pattern" $matches
+            else
+                fail "unknown rule type: '$rule'"
+            fi
+        done < $ac_pats
+    fi
+
     ac_tmpb=$SHUNIT_TMPDIR/ac-conv-tmpb.v
     convert "2nd conversion of $ac_file" $ac_tmpb $ac_tmpa