[Mlir-commits] [mlir] [mlir] Print aliases for recursive types (PR #110346)

[llvmlistbot at llvm.org]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-mlir

Author: Shoaib Meenai (smeenai)

<details>
<summary>Changes</summary>

We're already keeping track of the alias depth to ensure that aliases
are printed before they're referenced. For recursive types, we can
additionally track whether an alias has been printed and only reference
it if so, to lift the restrictions on not printing aliases inside
mutable types.


---
Full diff: https://github.com/llvm/llvm-project/pull/110346.diff


2 Files Affected:

- (modified) mlir/lib/IR/AsmPrinter.cpp (+8-5) 
- (modified) mlir/test/IR/recursive-type.mlir (+11) 


``````````diff
diff --git a/mlir/lib/IR/AsmPrinter.cpp b/mlir/lib/IR/AsmPrinter.cpp
index d0fd8e420d38ea..7f95f5ace8c00f 100644
--- a/mlir/lib/IR/AsmPrinter.cpp
+++ b/mlir/lib/IR/AsmPrinter.cpp
@@ -545,6 +545,10 @@ class SymbolAlias {
   bool isType : 1;
   /// A flag indicating whether this alias may be deferred or not.
   bool isDeferrable : 1;
+
+public:
+  /// Used to avoid printing incomplete aliases for recursive types.
+  bool isPrinted = false;
 };
 
 /// This class represents a utility that initializes the set of attribute and
@@ -1222,6 +1226,8 @@ LogicalResult AliasState::getAlias(Type ty, raw_ostream &os) const {
   const auto *it = attrTypeToAlias.find(ty.getAsOpaquePointer());
   if (it == attrTypeToAlias.end())
     return failure();
+  if (!it->second.isPrinted)
+    return failure();
 
   it->second.print(os);
   return success();
@@ -1238,12 +1244,9 @@ void AliasState::printAliases(AsmPrinter::Impl &p, NewLineCounter &newLine,
     p.getStream() << " = ";
 
     if (alias.isTypeAlias()) {
-      // TODO: Support nested aliases in mutable types.
       Type type = Type::getFromOpaquePointer(opaqueSymbol);
-      if (type.hasTrait<TypeTrait::IsMutable>())
-        p.getStream() << type;
-      else
-        p.printTypeImpl(type);
+      p.printTypeImpl(type);
+      alias.isPrinted = true;
     } else {
       // TODO: Support nested aliases in mutable attributes.
       Attribute attr = Attribute::getFromOpaquePointer(opaqueSymbol);
diff --git a/mlir/test/IR/recursive-type.mlir b/mlir/test/IR/recursive-type.mlir
index 121ba095573baa..42aecb41d998d1 100644
--- a/mlir/test/IR/recursive-type.mlir
+++ b/mlir/test/IR/recursive-type.mlir
@@ -2,7 +2,10 @@
 
 // CHECK: !testrec = !test.test_rec<type_to_alias, test_rec<type_to_alias>>
 // CHECK: ![[$NAME:.*]] = !test.test_rec_alias<name, !test.test_rec_alias<name>>
+// CHECK: ![[$NAME5:.*]] = !test.test_rec_alias<name5, !test.test_rec_alias<name3, !test.test_rec_alias<name4, !test.test_rec_alias<name5>>>>
 // CHECK: ![[$NAME2:.*]] = !test.test_rec_alias<name2, tuple<!test.test_rec_alias<name2>, i32>>
+// CHECK: ![[$NAME4:.*]] = !test.test_rec_alias<name4, !name5_>
+// CHECK: ![[$NAME3:.*]] = !test.test_rec_alias<name3, !name4_>
 
 // CHECK-LABEL: @roundtrip
 func.func @roundtrip() {
@@ -24,6 +27,14 @@ func.func @roundtrip() {
   // CHECK: () -> ![[$NAME2]]
   "test.dummy_op_for_roundtrip"() : () -> !test.test_rec_alias<name2, tuple<!test.test_rec_alias<name2>, i32>>
   "test.dummy_op_for_roundtrip"() : () -> !test.test_rec_alias<name2, tuple<!test.test_rec_alias<name2>, i32>>
+
+  // Mutual recursion.
+  // CHECK: () -> ![[$NAME3]]
+  // CHECK: () -> ![[$NAME4]]
+  // CHECK: () -> ![[$NAME5]]
+  "test.dummy_op_for_roundtrip"() : () -> !test.test_rec_alias<name3, !test.test_rec_alias<name4, !test.test_rec_alias<name5, !test.test_rec_alias<name3>>>>
+  "test.dummy_op_for_roundtrip"() : () -> !test.test_rec_alias<name4, !test.test_rec_alias<name5, !test.test_rec_alias<name3, !test.test_rec_alias<name4>>>>
+  "test.dummy_op_for_roundtrip"() : () -> !test.test_rec_alias<name5, !test.test_rec_alias<name3, !test.test_rec_alias<name4, !test.test_rec_alias<name5>>>>
   return
 }
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/110346