[mlir][dxsa] Add dcl_interface and dcl_interface_dynamicindexed

dcl_interface binds multiple dcl_function_table declarations, so they
can be accessed either statically or dynamically. Each table is bound
at runtime, but the compiler must know every variant to generate a
specialized version of the shader.

Author: asavonic

mlir/include/mlir/Dialect/DXSA/IR/DXSAOps.td

@@ -255,6 +255,23 @@ def DXSA_SystemValueNameAttr :
   let assemblyFormat = "$value";
 }
 
+def DXSA_InterfaceAccess_Immediate : I32EnumAttrCase<"immediate", 0>;
+def DXSA_InterfaceAccess_Dynamic   : I32EnumAttrCase<"dynamic",   1>;
+
+def DXSA_InterfaceAccess : I32EnumAttr<
+    "InterfaceAccess", "DXBC access kind for an interface", [
+      DXSA_InterfaceAccess_Immediate,
+      DXSA_InterfaceAccess_Dynamic
+    ]> {
+  let cppNamespace = "::mlir::dxsa";
+  let genSpecializedAttr = 0;
+}
+
+def DXSA_InterfaceAccessAttr :
+    EnumAttr<DXSADialect, DXSA_InterfaceAccess, "interface_access"> {
+  let assemblyFormat = "$value";
+}
+
 //===----------------------------------------------------------------------===//
 // DXSA ComponentMask bit-enum (mask field of operand, normalized to bits 0..3)
 //===----------------------------------------------------------------------===//
@@ -758,4 +775,28 @@ def DXSA_DclFunctionTable : DXSA_Op<"dcl_function_table"> {
   let assemblyFormat = "$index `,` $functions attr-dict";
 }
 
+def DXSA_DclInterface : DXSA_Op<"dcl_interface"> {
+  let summary = "declares function table pointers (interfaces)";
+  let description = [{
+
+    Declare an `array_length` of function table pointers
+    (interfaces). Each table can be bound at runtime, and it should
+    contain `table_length` function bodies.
+
+    Example:
+    ```mlir
+    dxsa.dcl_function_body 0
+    dxsa.dcl_function_body 1
+    dxsa.dcl_function_table 0, [0, 1]
+    dxsa.dcl_interface 1, <access = dynamic, array_length = 1, table_length = 2> [0]
+    ```
+  }];
+  let arguments = (ins I32Attr:$index, DXSA_InterfaceAccessAttr:$access, I32Attr:$array_length, I32Attr:$table_length, DenseI32ArrayAttr:$tables);
+  let assemblyFormat = [{ $index `,` `<`
+    `access` `=` $access `,`
+    `array_length` `=` $array_length `,`
+    `table_length` `=` $table_length `>` `,` $tables attr-dict
+  }];
+}
+
 #endif // DXSA_OPS

mlir/lib/Target/DXSA/BinaryParser.cpp

@@ -646,6 +646,16 @@ class DXBuilder {
         builder, loc, index, DenseI32ArrayAttr::get(ctx, functions));
   }
 
+  Instruction buildDclInterface(uint32_t index,
+				dxsa::InterfaceAccess access,
+				uint32_t arrayLength,
+                                uint32_t tableLength,
+                                ArrayRef<int32_t> tables, Location loc) {
+    auto *ctx = builder.getContext();
+    return dxsa::DclInterface::create(builder, loc, index, access, arrayLength, tableLength,
+                                      DenseI32ArrayAttr::get(ctx, tables));
+  }
+
 private:
   MLIRContext *context;
   ModuleOp module;
@@ -1209,6 +1219,41 @@ class Parser {
     return builder.buildDclFunctionTable(*index, functions, loc);
   }
 
+  FailureOr<Instruction> parseDclInterface(uint32_t opcodeToken, Location loc) {
+    bool isDynamic = DECODE_D3D11_SB_INTERFACE_INDEXED_BIT(opcodeToken);
+    auto access = dxsa::symbolizeInterfaceAccess(isDynamic);
+    assert(access && "unhandled interface access kind"); // access kind is 1 bit
+
+    // Index of the interface (start index for an array).
+    Token index = parseToken();
+    FAILURE_IF_FAILED(index);
+
+    // Expected function table length.
+    Token tableLength = parseToken();
+    FAILURE_IF_FAILED(tableLength);
+
+    Token interfaceArrayLength = parseToken();
+    FAILURE_IF_FAILED(interfaceArrayLength);
+
+    // Number of call sites.
+    uint32_t interfaceLength =
+        DECODE_D3D11_SB_INTERFACE_TABLE_LENGTH(*interfaceArrayLength);
+
+    // Number of interfaces.
+    uint32_t arrayLength =
+        DECODE_D3D11_SB_INTERFACE_ARRAY_LENGTH(*interfaceArrayLength);
+
+    SmallVector<int32_t, 16> tables;
+    tables.resize(interfaceLength);
+    for (uint32_t i = 0; i < interfaceLength; ++i) {
+      Token tableIndex = parseToken();
+      FAILURE_IF_FAILED(tableIndex);
+      tables[i] = *tableIndex;
+    }
+
+    return builder.buildDclInterface(*index, *access, arrayLength, *tableLength, tables, loc);
+  }
+
   OptionalParseResult parseDclInstruction(uint32_t opcodeToken, Location loc,
                                           Instruction &out) {
     FailureOr<Instruction> result;
@@ -1261,6 +1306,9 @@ class Parser {
     case D3D11_SB_OPCODE_DCL_FUNCTION_TABLE:
       result = parseDclFunctionTable(loc);
       break;
+    case D3D11_SB_OPCODE_DCL_INTERFACE:
+      result = parseDclInterface(opcodeToken, loc);
+      break;
     default:
       return std::nullopt;
     }

mlir/test/Target/DXSA/dcl_interface.mlir

@@ -0,0 +1,9 @@
+// RUN: mlir-translate --import-dxsa-bin %S/inputs/dcl_interface.bin | FileCheck %s
+
+// CHECK-LABEL: module
+
+// dcl_interface fp0[253][1] = {ft0, ft1}
+// CHECK-NEXT: dxsa.dcl_interface 0, <access = dynamic, array_length = 253, table_length = 1>, [0, 1]
+
+// dcl_interface_dynamicindexed fp0[253][1] = {ft0, ft1}
+// CHECK-NEXT: dxsa.dcl_interface 0, <access = immediate, array_length = 253, table_length = 1>, [0, 1]