assign: avoid clearing unrelated fields in variant objects (#55)

arnetheduck · Sep 22, 2023 · 99fe817 · 99fe817
1 parent f3a9bb4
commit 99fe817
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Showing 2 changed files with 6 additions and 5 deletions.
diff --git a/Nim b/Nim
diff --git a/nlvm/llgen.nim b/nlvm/llgen.nim
@@ -3830,9 +3830,11 @@ proc genAssignFields(
     for child in n:
       g.genAssignFields(mapper, child, ty, dest, src, shallow)
   of nkRecCase:
-    block: # Reset the destination which releases all held memory
-      var resetMapper = mapper
-      g.genResetFields(resetMapper, n, ty, LLValue(v: dest))
+    block: # Reset kind-specific fields of the destination
+      # TODO: we could skip this if tag is unchanged
+      var mapper = mapper
+      withRecCase(n, ty, dest):
+        g.genResetFields(recMapper, branch.lastSon, branchTy, LLValue(v: storeGEP))
 
     block: # Set field discriminator and copy fields
       withRecCase(n, ty, src):
@@ -7668,7 +7670,6 @@ proc genNodeObjConstr(g: LLGen, n: PNode, load: bool, dest: LLValue): LLValue =
     else:
       g.callReset(typ, dest)
       dest
-
   for i in 1 ..< n.len:
     let
       s = n[i]