New duration representation (#161)

This PR introduces a typed MLIR encoding of durations and replaces the
previous string-based representation.

This will yield a large performance improvement as it avoids additional
string parsing and will enable leveraging MLIR's type/conversion
systems.

Author: taalexander

include/Dialect/QUIR/IR/CMakeLists.txt

@@ -17,4 +17,8 @@ set(LLVM_TARGET_DEFINITIONS QUIR.td)
 mlir_tablegen(QUIRAttributes.h.inc -gen-attrdef-decls -attrdefs-dialect=quir)
 mlir_tablegen(QUIRAttributes.cpp.inc -gen-attrdef-defs -attrdefs-dialect=quir)
 
+set(LLVM_TARGET_DEFINITIONS QUIR.td)
+mlir_tablegen(QUIREnums.h.inc -gen-enum-decls)
+mlir_tablegen(QUIREnums.cpp.inc -gen-enum-defs)
+
 add_mlir_interface(QUIRInterfaces)

include/Dialect/QUIR/IR/QUIR.td

@@ -18,5 +18,11 @@
 #define QUIR_TD
 
 include "Dialect/QUIR/IR/QUIRDialect.td"
+include "Dialect/QUIR/IR/QUIREnums.td"
+include "Dialect/QUIR/IR/QUIRTypes.td"
+include "Dialect/QUIR/IR/QUIRTypeConstraints.td"
+include "Dialect/QUIR/IR/QUIRAttributes.td"
+include "Dialect/QUIR/IR/QUIRTraits.td"
+include "Dialect/QUIR/IR/QUIROps.td"
 
 #endif // QUIR_TD

include/Dialect/QUIR/IR/QUIRAttributes.h

@@ -28,11 +28,10 @@
 
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/TypeSwitch.h"
-
-#define GET_ATTRDEF_CLASSES
-#include "Dialect/QUIR/IR/QUIRAttributes.h.inc"
+#include "llvm/Support/Error.h"
 
 namespace mlir::quir {
+
 static inline llvm::StringRef getInputParameterAttrName() {
   return "quir.inputParameter";
 }
@@ -57,4 +56,7 @@ static inline llvm::StringRef getDurationAttrName() {
 
 } // namespace mlir::quir
 
+#define GET_ATTRDEF_CLASSES
+#include "Dialect/QUIR/IR/QUIRAttributes.h.inc"
+
 #endif // QUIR_QUIRATTRIBUTES_H

include/Dialect/QUIR/IR/QUIRAttributes.td

@@ -18,6 +18,9 @@
 #ifndef QUIR_ATTRIBUTES
 #define QUIR_ATTRIBUTES
 
+include "Dialect/QUIR/IR/QUIRTypes.td"
+
+include "mlir/IR/BuiltinAttributes.td"
 include "mlir/IR/OpBase.td"
 
 def QUIR_AngleAttr : QUIR_Attr<"Angle", "angle"> {
@@ -46,15 +49,20 @@ def QUIR_AngleAttr : QUIR_Attr<"Angle", "angle"> {
 def QUIR_DurationAttr : QUIR_Attr<"Duration", "duration"> {
   let summary = "A duration of time";
   let description = [{
-    Duration attributes represent OpenQASM 3.0 durations, which are lengths of
-    time. They are represented by a string containing a float literal and unit
-    specifiers. Valid units are s, ms, ns, us, and dt.
+    Duration attributes represent a duration of time.
+    These are represented by a floating point value and a duration
+    units type.
   }];
 
-  let parameters = (ins AttributeSelfTypeParameter<"">:$type,
-                        StringRefParameter<"the duration">:$value);
+  let parameters = (ins AttributeSelfTypeParameter<"", "DurationType">:$type,
+                        "APFloat":$duration);
+
+  let extraClassDeclaration = [{
+        uint64_t getSchedulingCycles(const double dt);
+    }];
+
+  let assemblyFormat = "`<` $duration `:` $type `>`";
 
-  let assemblyFormat = "`<` $value `:` $type `>`";
 }
 
 def QUIR_InputParameterAttr : QUIR_Attr<"InputParameter", "inputParameter"> {

include/Dialect/QUIR/IR/QUIRDialect.td

@@ -57,10 +57,4 @@ class QUIR_Attr<string name, string attrMnemonic, list<Trait> traits = []>
   let mnemonic = attrMnemonic;
 }
 
-include "Dialect/QUIR/IR/QUIRTypes.td"
-include "Dialect/QUIR/IR/QUIRTypeConstraints.td"
-include "Dialect/QUIR/IR/QUIRAttributes.td"
-include "Dialect/QUIR/IR/QUIRTraits.td"
-include "Dialect/QUIR/IR/QUIROps.td"
-
 #endif // QUIR_DIALECT

include/Dialect/QUIR/IR/QUIREnums.h

@@ -0,0 +1,30 @@
+//===- QUIREnums.h - QUIR dialect enums -------------------------*- C++ -*-===//
+//
+// (C) Copyright IBM 2023.
+//
+// This code is part of Qiskit.
+//
+// This code is licensed under the Apache License, Version 2.0 with LLVM
+// Exceptions. You may obtain a copy of this license in the LICENSE.txt
+// file in the root directory of this source tree.
+//
+// Any modifications or derivative works of this code must retain this
+// copyright notice, and modified files need to carry a notice indicating
+// that they have been altered from the originals.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef QUIR_QUIRENUMS_H
+#define QUIR_QUIRENUMS_H
+
+#include "mlir/IR/BuiltinTypes.h"
+#include "mlir/IR/Dialect.h"
+#include "mlir/IR/DialectImplementation.h"
+#include "mlir/IR/OpDefinition.h"
+
+#define GET_ENUM_CLASSES
+#include "Dialect/QUIR/IR/QUIREnums.h.inc"
+
+namespace mlir {} // namespace mlir
+
+#endif // QUIR_QUIRENUMS_H

include/Dialect/QUIR/IR/QUIREnums.td

@@ -0,0 +1,47 @@
+//===- QUIREnums.td - QUIR dialect enums -------------------*- tablegen -*-===//
+//
+// (C) Copyright IBM 2023.
+//
+// This code is part of Qiskit.
+//
+// This code is licensed under the Apache License, Version 2.0 with LLVM
+// Exceptions. You may obtain a copy of this license in the LICENSE.txt
+// file in the root directory of this source tree.
+//
+// Any modifications or derivative works of this code must retain this
+// copyright notice, and modified files need to carry a notice indicating
+// that they have been altered from the originals.
+//
+//===----------------------------------------------------------------------===//
+
+
+#ifndef QUIR_ENUMS
+#define QUIR_ENUMS
+
+include "Dialect/QUIR/IR/QUIRDialect.td"
+
+include "mlir/IR/EnumAttr.td"
+
+def TimeUnits : I32EnumAttr<
+    "TimeUnits", "time units enum",
+    [
+      // dt is the "scheduling rate" of the target system
+      // ie., the smallest step of time exposed.
+      I32EnumAttrCase<"dt", 0>,
+      I32EnumAttrCase<"s", 1>,
+      I32EnumAttrCase<"ms", 2>,
+      I32EnumAttrCase<"us", 3>,
+      I32EnumAttrCase<"ns", 4>,
+      I32EnumAttrCase<"ps", 5>,
+      I32EnumAttrCase<"fs", 6>,
+
+    ]> {
+  let genSpecializedAttr = 0;
+  let cppNamespace = "::mlir::quir";
+
+}
+
+def QUIR_TimeUnitsAttr : EnumAttr<
+  QUIRDialect, TimeUnits, "time_units">;
+
+#endif // QUIR_ENUMS

include/Dialect/QUIR/IR/QUIROps.td

@@ -485,8 +485,8 @@ def QUIR_DelayOp : QUIR_Op<"delay", [
 
         Example:
         ```mlir
-        %dur1 = quir.declare_duration {value = "10ns"} : !quir.duration
-        "quir.delay"(%dur1, %q1_1) : (!quir.duration, !quir.qubit)
+        %dur1 = quir.constant #quir.duration<10.0 : !quir.duration<dt>>
+        "quir.delay"(%dur1, %q1_1) : (!quir.duration<dt>, !quir.qubit)
         ```
     }];
 

include/Dialect/QUIR/IR/QUIRTypes.h

@@ -17,6 +17,8 @@
 #ifndef QUIR_QUIRTYPES_H
 #define QUIR_QUIRTYPES_H
 
+#include "Dialect/QUIR/IR/QUIREnums.h"
+
 #include "mlir/IR/BuiltinTypes.h"
 #include "mlir/IR/Dialect.h"
 #include "mlir/IR/OpDefinition.h"

include/Dialect/QUIR/IR/QUIRTypes.td

@@ -17,6 +17,8 @@
 #ifndef QUIR_TYPES
 #define QUIR_TYPES
 
+include "Dialect/QUIR/IR/QUIREnums.td"
+
 include "mlir/IR/BuiltinTypeInterfaces.td"
 include "mlir/IR/OpBase.td"
 
@@ -60,11 +62,28 @@ def QUIR_AngleType : QUIR_Type<"Angle", "angle"> {
     let genVerifyDecl = 1;
 }
 
+
+
 def QUIR_DurationType : QUIR_Type<"Duration", "duration"> {
-    let summary = "represents a duration of time as a string w/ specified units.";
+    let summary = "represents a duration of time.";
     let description = [{
-        A QUIR duration expresses timing.
+        A QUIR duration type.
+
+        Example:
+            ```mlir
+                // Defaults to units at the scheduling rate (dt)
+                %duration_dt = quir.constant #quir.duration<10.0 : !quir.duration>
+                %duration_s = quir.constant #quir.duration<3.14 : !quir.duration<s>>
+            ```
+
      }];
+
+    // As best I an tell this is undocumented in LLVM 14.
+    // Based on studying the implementation of EnumAttr
+    // https://github.com/llvm/llvm-project/blob/f28c006a5895fc0e329fe15fead81e37457cb1d1/mlir/include/mlir/IR/EnumAttr.td#L86
+    let parameters = (ins EnumParameter<TimeUnits>:$units);
+
+    let assemblyFormat = "`<` $units `>`";
 }
 
 def QUIR_StretchType : QUIR_Type<"Stretch", "stretch"> {