[spirv] Add spv.ReturnValue

This CL adds the spv.ReturnValue op and its tests. Also adds a
InFunctionScope trait to make sure that the op stays inside
a function. To be consistent, ModuleOnly trait is changed to
InModuleScope.

PiperOrigin-RevId: 264193081

mlir/include/mlir/Dialect/SPIRV/SPIRVBase.td

@@ -128,6 +128,7 @@ def SPV_OC_OpSLessThan             : I32EnumAttrCase<"OpSLessThan", 177>;
 def SPV_OC_OpULessThanEqual        : I32EnumAttrCase<"OpULessThanEqual", 178>;
 def SPV_OC_OpSLessThanEqual        : I32EnumAttrCase<"OpSLessThanEqual", 179>;
 def SPV_OC_OpReturn                : I32EnumAttrCase<"OpReturn", 253>;
+def SPV_OC_OpReturnValue           : I32EnumAttrCase<"OpReturnValue", 254>;
 
 def SPV_OpcodeAttr :
     I32EnumAttr<"Opcode", "valid SPIR-V instructions", [
@@ -146,7 +147,7 @@ def SPV_OpcodeAttr :
       SPV_OC_OpFMod, SPV_OC_OpIEqual, SPV_OC_OpINotEqual, SPV_OC_OpUGreaterThan,
       SPV_OC_OpSGreaterThan, SPV_OC_OpUGreaterThanEqual, SPV_OC_OpSGreaterThanEqual,
       SPV_OC_OpULessThan, SPV_OC_OpSLessThan, SPV_OC_OpULessThanEqual,
-      SPV_OC_OpSLessThanEqual, SPV_OC_OpReturn
+      SPV_OC_OpSLessThanEqual, SPV_OC_OpReturn, SPV_OC_OpReturnValue
       ]> {
     let returnType = "::mlir::spirv::Opcode";
     let convertFromStorage = "static_cast<::mlir::spirv::Opcode>($_self.getInt())";
@@ -778,12 +779,15 @@ def SPV_SamplerUseAttr:
 // SPIR-V OpTrait definitions
 //===----------------------------------------------------------------------===//
 
-// Check that an op can only be used with SPIR-V ModuleOp
-def IsModuleOnlyPred :
-  CPred<"llvm::isa_and_nonnull<spirv::ModuleOp>($_op.getParentOp())">;
+// Check that an op can only be used within the scope of a FuncOp.
+def InFunctionScope : PredOpTrait<
+  "op must appear in a 'func' block",
+  CPred<"llvm::isa_and_nonnull<FuncOp>($_op.getParentOp())">>;
 
-def ModuleOnly :
-  PredOpTrait<"op can only be used in a 'spv.module' block", IsModuleOnlyPred>;
+// Check that an op can only be used within the scope of a SPIR-V ModuleOp.
+def InModuleScope : PredOpTrait<
+  "op must appear in a 'spv.module' block",
+  CPred<"llvm::isa_and_nonnull<spirv::ModuleOp>($_op.getParentOp())">>;
 
 //===----------------------------------------------------------------------===//
 // SPIR-V op definitions

mlir/include/mlir/Dialect/SPIRV/SPIRVOps.td

@@ -146,7 +146,7 @@ def SPV_CompositeExtractOp : SPV_Op<"CompositeExtract", [NoSideEffect]> {
 
 // -----
 
-def SPV_ExecutionModeOp : SPV_Op<"ExecutionMode", [ModuleOnly]> {
+def SPV_ExecutionModeOp : SPV_Op<"ExecutionMode", [InModuleScope]> {
   let summary = "Declare an execution mode for an entry point.";
 
   let description = [{
@@ -599,7 +599,7 @@ def SPV_LoadOp : SPV_Op<"Load", []> {
 
 // -----
 
-def SPV_ReturnOp : SPV_Op<"Return", [Terminator]> {
+def SPV_ReturnOp : SPV_Op<"Return", [InFunctionScope, Terminator]> {
   let summary = "Return with no value from a function with void return type.";
 
   let description = [{
@@ -624,6 +624,38 @@ def SPV_ReturnOp : SPV_Op<"Return", [Terminator]> {
 
 // -----
 
+def SPV_ReturnValueOp : SPV_Op<"ReturnValue", [InFunctionScope, Terminator]> {
+  let summary = "Return a value from a function.";
+
+  let description = [{
+    Value is the value returned, by copy, and must match the Return Type
+    operand of the OpTypeFunction type of the OpFunction body this return
+    instruction is in.
+
+    This instruction must be the last instruction in a block.
+
+    ### Custom assembly form
+
+    ``` {.ebnf}
+    return-value-op ::= `spv.ReturnValue` ssa-use `:` spirv-type
+    ```
+
+    For example:
+
+    ```
+    spv.ReturnValue %0 : f32
+    ```
+  }];
+
+  let arguments = (ins
+    SPV_Type:$value
+  );
+
+  let results = (outs);
+}
+
+// -----
+
 def SPV_SDivOp : SPV_ArithmeticOp<"SDiv", SPV_Integer> {
   let summary = "Signed-integer division of Operand 1 divided by Operand 2.";
 

mlir/include/mlir/Dialect/SPIRV/SPIRVStructureOps.td

@@ -30,7 +30,7 @@
 include "mlir/SPIRV/SPIRVBase.td"
 #endif // SPIRV_BASE
 
-def SPV_AddressOfOp : SPV_Op<"_address_of", [NoSideEffect]> {
+def SPV_AddressOfOp : SPV_Op<"_address_of", [InFunctionScope, NoSideEffect]> {
   let summary = "Get the address of a global variable.";
 
   let description = [{
@@ -66,7 +66,7 @@ def SPV_AddressOfOp : SPV_Op<"_address_of", [NoSideEffect]> {
   let hasOpcode = 0;
 }
 
-def SPV_EntryPointOp : SPV_Op<"EntryPoint", [ModuleOnly]> {
+def SPV_EntryPointOp : SPV_Op<"EntryPoint", [InModuleScope]> {
   let summary = [{
     Declare an entry point, its execution model, and its interface.
   }];
@@ -122,7 +122,7 @@ def SPV_EntryPointOp : SPV_Op<"EntryPoint", [ModuleOnly]> {
 }
 
 
-def SPV_GlobalVariableOp : SPV_Op<"globalVariable", [ModuleOnly]> {
+def SPV_GlobalVariableOp : SPV_Op<"globalVariable", [InModuleScope]> {
   let summary = [{
     Allocate an object in memory at module scope. The object is
     referenced using a symbol name.
@@ -264,7 +264,7 @@ def SPV_ModuleOp : SPV_Op<"module",
   }];
 }
 
-def SPV_ModuleEndOp : SPV_Op<"_module_end", [Terminator, ModuleOnly]> {
+def SPV_ModuleEndOp : SPV_Op<"_module_end", [InModuleScope, Terminator]> {
   let summary = "The pseudo op that ends a SPIR-V module";
 
   let description = [{

mlir/lib/Dialect/SPIRV/SPIRVOps.cpp

@@ -1042,10 +1042,7 @@ static LogicalResult verify(spirv::ModuleOp moduleOp) {
 //===----------------------------------------------------------------------===//
 
 static LogicalResult verifyReturn(spirv::ReturnOp returnOp) {
-  auto funcOp = llvm::dyn_cast<FuncOp>(returnOp.getOperation()->getParentOp());
-  if (!funcOp)
-    return returnOp.emitOpError("must appear in a 'func' op");
-
+  auto funcOp = llvm::cast<FuncOp>(returnOp.getParentOp());
   auto numOutputs = funcOp.getType().getNumResults();
   if (numOutputs != 0)
     return returnOp.emitOpError("cannot be used in functions returning value")
@@ -1054,6 +1051,43 @@ static LogicalResult verifyReturn(spirv::ReturnOp returnOp) {
   return success();
 }
 
+//===----------------------------------------------------------------------===//
+// spv.ReturnValue
+//===----------------------------------------------------------------------===//
+
+static ParseResult parseReturnValueOp(OpAsmParser *parser,
+                                      OperationState *state) {
+  OpAsmParser::OperandType retValInfo;
+  Type retValType;
+  return failure(
+      parser->parseOperand(retValInfo) || parser->parseColonType(retValType) ||
+      parser->resolveOperand(retValInfo, retValType, state->operands));
+}
+
+static void print(spirv::ReturnValueOp retValOp, OpAsmPrinter *printer) {
+  *printer << spirv::ReturnValueOp::getOperationName() << ' ';
+  printer->printOperand(retValOp.value());
+  *printer << " : " << retValOp.value()->getType();
+}
+
+static LogicalResult verify(spirv::ReturnValueOp retValOp) {
+  auto funcOp = llvm::cast<FuncOp>(retValOp.getParentOp());
+  auto numFnResults = funcOp.getType().getNumResults();
+  if (numFnResults != 1)
+    return retValOp.emitOpError(
+               "returns 1 value but enclosing function requires ")
+           << numFnResults << " results";
+
+  auto operandType = retValOp.value()->getType();
+  auto fnResultType = funcOp.getType().getResult(0);
+  if (operandType != fnResultType)
+    return retValOp.emitOpError(" return value's type (")
+           << operandType << ") mismatch with function's result type ("
+           << fnResultType << ")";
+
+  return success();
+}
+
 //===----------------------------------------------------------------------===//
 // spv.StoreOp
 //===----------------------------------------------------------------------===//

mlir/test/Dialect/SPIRV/Serialization/terminator.mlir

@@ -0,0 +1,21 @@
+// RUN: mlir-translate -serialize-spirv %s | mlir-translate -deserialize-spirv | FileCheck %s
+
+func @spirv_terminator() -> () {
+  spv.module "Logical" "GLSL450" {
+    // CHECK-LABEL: @ret
+    func @ret() -> () {
+      // CHECK: spv.Return
+      spv.Return
+    }
+
+    // CHECK-LABEL: @ret_val
+    func @ret_val() -> (i32) {
+      %0 = spv.Variable : !spv.ptr<i32, Function>
+      %1 = spv.Load "Function" %0 : i32
+      // CHECK: spv.ReturnValue {{.*}} : i32
+      spv.ReturnValue %1 : i32
+    }
+  }
+  return
+}
+

mlir/test/Dialect/SPIRV/ops.mlir

@@ -327,7 +327,7 @@ spv.module "Logical" "VulkanKHR" {
 
 spv.module "Logical" "VulkanKHR" {
    func @do_nothing() -> () {
-     // expected-error @+1 {{'spv.EntryPoint' op failed to verify that op can only be used in a 'spv.module' block}}
+     // expected-error @+1 {{op must appear in a 'spv.module' block}}
      spv.EntryPoint "GLCompute" @do_something
    }
 }
@@ -451,7 +451,7 @@ spv.module "Logical" "VulkanKHR" {
 
 spv.module "Logical" "VulkanKHR" {
   func @foo() {
-    // expected-error @+1 {{op failed to verify that op can only be used in a 'spv.module' block}}
+    // expected-error @+1 {{op must appear in a 'spv.module' block}}
     spv.globalVariable !spv.ptr<f32, Input> @var0
     spv.Return
   }
@@ -767,7 +767,7 @@ spv.module "Logical" "VulkanKHR" {
 //===----------------------------------------------------------------------===//
 
 "foo.function"() ({
-  // expected-error @+1 {{must appear in a 'func' op}}
+  // expected-error @+1 {{op must appear in a 'func' block}}
   spv.Return
 })  : () -> ()
 
@@ -783,6 +783,41 @@ spv.module "Logical" "VulkanKHR" {
 
 // -----
 
+//===----------------------------------------------------------------------===//
+// spv.ReturnValue
+//===----------------------------------------------------------------------===//
+
+func @ret_val() -> (i32) {
+  %0 = spv.constant 42 : i32
+  spv.ReturnValue %0 : i32
+}
+
+// -----
+
+"foo.function"() ({
+  %0 = spv.constant true
+  // expected-error @+1 {{op must appear in a 'func' block}}
+  spv.ReturnValue %0 : i1
+})  : () -> ()
+
+// -----
+
+func @value_count_mismatch() -> () {
+  %0 = spv.constant 42 : i32
+  // expected-error @+1 {{op returns 1 value but enclosing function requires 0 results}}
+  spv.ReturnValue %0 : i32
+}
+
+// -----
+
+func @value_type_mismatch() -> (f32) {
+  %0 = spv.constant 42 : i32
+  // expected-error @+1 {{return value's type ('i32') mismatch with function's result type ('f32')}}
+  spv.ReturnValue %0 : i32
+}
+
+// -----
+
 //===----------------------------------------------------------------------===//
 // spv.SDiv
 //===----------------------------------------------------------------------===//

mlir/test/Dialect/SPIRV/structure-ops.mlir

@@ -1,5 +1,17 @@
 // RUN: mlir-opt -split-input-file -verify-diagnostics %s | FileCheck %s
 
+//===----------------------------------------------------------------------===//
+// spv._address_of
+//===----------------------------------------------------------------------===//
+
+spv.module "Logical" "GLSL450" {
+  spv.globalVariable !spv.ptr<!spv.struct<f32, !spv.array<4xf32>>, Input> @var
+  // expected-error @+1 {{op must appear in a 'func' block}}
+  %1 = spv._address_of @var : !spv.ptr<!spv.struct<f32, !spv.array<4xf32>>, Input>
+}
+
+// -----
+
 //===----------------------------------------------------------------------===//
 // spv.constant
 //===----------------------------------------------------------------------===//
@@ -171,6 +183,6 @@ spv.module "Logical" "VulkanKHR" {
 //===----------------------------------------------------------------------===//
 
 func @module_end_not_in_module() -> () {
-  // expected-error @+1 {{can only be used in a 'spv.module' block}}
+  // expected-error @+1 {{op must appear in a 'spv.module' block}}
   spv._module_end
 }