[mlir][linalg] Fix crashes in parser on linalg ops without operands

[ubfx]

parseDstStyleOp parses both ins() and outs() optionally. The parsers for linalg.transpose, linalg.broadcast and linalg.map however assume that at least one operand is present in the state, leading to crashes otherwise.

This patch adds checks to the parsers which stop them from crashing if no operands were parsed. After the Ops are parsed successfuly, the verifier takes it from there.

Fix #97857

[llvmbot]

@llvm/pr-subscribers-mlir

@llvm/pr-subscribers-mlir-linalg

Author: Felix Schneider (ubfx)

Changes

parseDstStyleOp parses both ins() and outs() optionally. The parsers for linalg.transpose, linalg.broadcast and linalg.map however assume that at least one operand is present in the state, leading to crashes otherwise.

This patch adds checks to the parsers which stop them from crashing if no operands were parsed. After the Ops are parsed successfuly, the verifier takes it from there.

Fix #97857

---

Full diff: https://github.com/llvm/llvm-project/pull/97944.diff

2 Files Affected:

• (modified) mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp (+6-3)
• (modified) mlir/test/Dialect/Linalg/invalid.mlir (+31)

diff --git a/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp b/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp
index 57d126603ebd7..dec84ed579096 100644
--- a/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp
+++ b/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp
@@ -1356,8 +1356,10 @@ ParseResult MapOp::parse(OpAsmParser &parser, OperationState &result) {
     return failure();
 
   if (payloadOpName.has_value()) {
-    addBodyWithPayloadOp(parser, result, payloadOpName.value(), payloadOpAttrs,
-                         ArrayRef(result.operands).drop_back());
+    if (!result.operands.empty())
+      addBodyWithPayloadOp(parser, result, payloadOpName.value(),
+                           payloadOpAttrs,
+                           ArrayRef(result.operands).drop_back());
   } else {
     SmallVector<OpAsmParser::Argument> regionArgs;
     if (parser.parseArgumentList(regionArgs, OpAsmParser::Delimiter::Paren,
@@ -1739,7 +1741,8 @@ static void buildIdentityRegion(OpBuilder &builder, Location loc,
                                 ValueRange outputs) {
   buildGenericRegion(builder, loc, region, inputs, outputs,
                      [](OpBuilder &b, Location loc, ValueRange args) {
-                       b.create<linalg::YieldOp>(loc, args[0]);
+                       if (!args.empty())
+                         b.create<linalg::YieldOp>(loc, args[0]);
                      });
 }
 
diff --git a/mlir/test/Dialect/Linalg/invalid.mlir b/mlir/test/Dialect/Linalg/invalid.mlir
index 44c81c31ace0f..cfd269e3e6e3a 100644
--- a/mlir/test/Dialect/Linalg/invalid.mlir
+++ b/mlir/test/Dialect/Linalg/invalid.mlir
@@ -455,6 +455,18 @@ func.func @map_input_output_shape_mismatch(
 
 // -----
 
+func.func @map_no_operands(
+    %lhs: tensor<64xf32>, %rhs: tensor<64xf32>, %init: tensor<64xf32>)
+    -> tensor<64xf32> {
+  // This must not crash the parser.
+  linalg.map { arith.addf }
+  // expected-error @+1 {{cannot name an operation with no results}}
+  %add = linalg.map { arith.addf }
+  func.return %add : tensor<64xf32>
+}
+
+// -----
+
 func.func @reduce_input_vs_init_dimension_mismatch(
     %input: tensor<16x32x64xf32>,
     %init: tensor<16x64xf32>)  -> tensor<16x64xf32> {
@@ -676,6 +688,16 @@ func.func @transpose_input_init_rank_mismatch(%input: tensor<16x32xf32>,
 
 // -----
 
+func.func @transpose_no_operands() -> tensor<32x64x16xf32> {
+  // This must not crash the parser.
+  linalg.transpose permutation = [1, 0, 2]
+  // expected-error @+1 {{cannot name an operation with no results}}
+  %transpose = linalg.transpose permutation = [1, 0, 2]
+  func.return %transpose : tensor<32x64x16xf32>
+}
+
+// -----
+
 func.func @broadcast_input_dims_rank_mismatch(
     %input: tensor<4x16xf32>, %init: tensor<4x8x16xf32>)
     -> tensor<4x8x16xf32> {
@@ -725,6 +747,15 @@ func.func @broadcast_size_1_extension_not_supported(
       dimensions = [1]
   func.return %bcast : tensor<4x?x16xf32>
 }
+// -----
+
+func.func @broadcast_no_operands()
+    -> tensor<4x?x16xf32> {
+  linalg.broadcast dimensions = [1]
+  // expected-error @+1 {{cannot name an operation with no results}}
+  %broadcast = linalg.broadcast dimensions = [1]
+  func.return %broadcast : tensor<32x64x16xf32>
+}
 
 // -----