viam: Extract RegisterRef and add AbiRegister

This allows the UME definition to reuse the generic `RegisterRef` record.

Author: Jozott00

vadl/main/vadl/ast/ViamLowering.java

@@ -2002,11 +2002,11 @@ public Optional<vadl.viam.Definition> visit(
   }
 
   /**
-   * Maps a {@link SpecialPurposeRegisterDefinition} to a {@link Abi.RegisterRef}.
+   * Maps a {@link SpecialPurposeRegisterDefinition} to a {@link Abi.AbiRegister}.
    * It expects only one register in the {@link SpecialPurposeRegisterDefinition}. Otherwise,
    * it will throw an error.
    */
-  private Abi.RegisterRef mapSingleSpecialPurposeRegisterDef(
+  private Abi.AbiRegister mapSingleSpecialPurposeRegisterDef(
       Map<Identifier, Expr> aliasLookup,
       SpecialPurposeRegisterDefinition specialPurposeRegisterDef) {
     return specialPurposeRegisterDef.exprs.stream()
@@ -2015,9 +2015,9 @@ private Abi.RegisterRef mapSingleSpecialPurposeRegisterDef(
   }
 
   /**
-   * Maps a {@link SpecialPurposeRegisterDefinition} to a list of {@link Abi.RegisterRef}.
+   * Maps a {@link SpecialPurposeRegisterDefinition} to a list of {@link Abi.AbiRegister}.
    */
-  private List<Abi.RegisterRef> mapSpecialPurposeRegistersDef(
+  private List<Abi.AbiRegister> mapSpecialPurposeRegistersDef(
       Map<Identifier, Expr> aliasLookup,
       SpecialPurposeRegisterDefinition specialPurposeRegisterDef) {
     return specialPurposeRegisterDef.exprs.stream()
@@ -2026,12 +2026,12 @@ private List<Abi.RegisterRef> mapSpecialPurposeRegistersDef(
   }
 
   /**
-   * Maps a {@link SpecialPurposeRegisterDefinition} to a list of {@link Abi.RegisterRef}.
+   * Maps a {@link SpecialPurposeRegisterDefinition} to a list of {@link Abi.AbiRegister}.
    */
-  private List<List<Abi.RegisterRef>> mapSpecialPurposeRegistersDefs(
+  private List<List<Abi.AbiRegister>> mapSpecialPurposeRegistersDefs(
       Map<Identifier, Expr> aliasLookup,
       List<SpecialPurposeRegisterDefinition> specialPurposeRegisterDefs) {
-    List<List<Abi.RegisterRef>> result = new ArrayList<>();
+    List<List<Abi.AbiRegister>> result = new ArrayList<>();
 
     for (var def : specialPurposeRegisterDefs) {
       var iter = def.exprs.stream()
@@ -2044,7 +2044,7 @@ private List<List<Abi.RegisterRef>> mapSpecialPurposeRegistersDefs(
     return result;
   }
 
-  private Abi.RegisterRef getRegisterRefByAliasOrRegister(
+  private Abi.AbiRegister getRegisterRefByAliasOrRegister(
       Map<Identifier, Expr> aliasLookup,
       ExpandedSequenceCallExpr aliasOrRegister) {
     if (aliasOrRegister instanceof ExpandedAliasDefSequenceCallExpr registerCallExpr) {
@@ -2055,10 +2055,10 @@ private Abi.RegisterRef getRegisterRefByAliasOrRegister(
   }
 
   /**
-   * Maps the aliases {@code alias register zero = X(0)} to {@link Abi.RegisterRef} to be
+   * Maps the aliases {@code alias register zero = X(0)} to {@link Abi.AbiRegister} to be
    * used in {@link Abi}.
    */
-  private Abi.RegisterRef mapAliasToRegisterRef(
+  private Abi.AbiRegister mapAliasToRegisterRef(
       Map<Identifier, Expr> aliasLookup,
       Identifier identifier) {
     var expr = ensureNonNull(aliasLookup.get(identifier),
@@ -2067,12 +2067,12 @@ private Abi.RegisterRef mapAliasToRegisterRef(
     return mapToRegisterRef(expr);
   }
 
-  private Abi.RegisterRef mapToRegisterRef(Expr expr) {
+  private Abi.AbiRegister mapToRegisterRef(Expr expr) {
     var pair = getRegisterFile(expr);
     var registerFile = pair.left();
     var index = pair.right();
 
-    return new Abi.RegisterRef(registerFile, index, new Abi.Alignment(-1), expr.location());
+    return new Abi.AbiRegister(registerFile, index, new Abi.Alignment(-1), expr.location());
   }
 
   /**

vadl/main/vadl/lcb/template/lib/Target/EmitCallingConvTableGenFilePass.java

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText : © 2025 TU Wien <vadl@tuwien.ac.at>
+// SPDX-FileCopyrightText : © 2025-2026 TU Wien <vadl@tuwien.ac.at>
 // SPDX-License-Identifier: GPL-3.0-or-later
 //
 // This program is free software: you can redistribute it and/or modify
@@ -79,7 +79,7 @@ protected Map<String, Object> createVariables(final PassResults passResults,
     var abi = specification.abi().orElseThrow();
     return Map.of(CommonVarNames.NAMESPACE,
         lcbConfiguration().targetName().value().toLowerCase(),
-        "calleeRegisters", abi.calleeSaved().stream().map(Abi.RegisterRef::render).toList(),
+        "calleeRegisters", abi.calleeSaved().stream().map(Abi.AbiRegister::render).toList(),
         "functionRegisterType", getFuncArgsAssignToReg(abi).type,
         "functionRegisters", getFuncArgsAssignToReg(abi),
         "returnIfTypes", returnIfTypes(abi));
@@ -90,7 +90,7 @@ private List<ReturnCCIfType> returnIfTypes(Abi abi) {
 
     for (var def : abi.returnRegisters()) {
       var ty = ValueType.from(def.get(0).registerFile().resultType()).get();
-      var regs = def.stream().map(Abi.RegisterRef::render).toList();
+      var regs = def.stream().map(Abi.AbiRegister::render).toList();
       var obj = new ReturnCCIfType(ty, regs);
       result.add(obj);
     }
@@ -106,7 +106,7 @@ private AssignToReg getFuncArgsAssignToReg(Abi abi) {
     return new AssignToReg(
         ValueType.from(abi.argumentRegisters().get(0).registerFile().resultType()).get()
             .getLlvmType(),
-        abi.argumentRegisters().stream().map(Abi.RegisterRef::render)
+        abi.argumentRegisters().stream().map(Abi.AbiRegister::render)
             .collect(Collectors.joining(", ")));
   }
 }

vadl/main/vadl/lcb/template/lib/Target/EmitISelLoweringCppFilePass.java

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText : © 2025 TU Wien <vadl@tuwien.ac.at>
+// SPDX-FileCopyrightText : © 2025-2026 TU Wien <vadl@tuwien.ac.at>
 // SPDX-License-Identifier: GPL-3.0-or-later
 //
 // This program is free software: you can redistribute it and/or modify
@@ -175,10 +175,10 @@ protected Map<String, Object> createVariables(final PassResults passResults,
     map.put("stackPointer", stackPointer);
     map.put("stackPointerByteSize", abi.stackPointer().registerFile().resultType().bitWidth() / 8);
     map.put("argumentRegisterClasses",
-        abi.argumentRegisters().stream().map(Abi.RegisterRef::registerFile).distinct()
+        abi.argumentRegisters().stream().map(Abi.AbiRegister::registerFile).distinct()
             .map(LlvmRegisterFile::new).map(this::mapLlvmRegisterClass).toList());
     map.put("argumentRegisters",
-        abi.argumentRegisters().stream().map(Abi.RegisterRef::render).toList());
+        abi.argumentRegisters().stream().map(Abi.AbiRegister::render).toList());
     map.put("stackPointerBitWidth", abi.stackPointer().registerFile().resultType().bitWidth());
     map.put("stackPointerType", stackPointerType.getLlvmType());
     map.put("absoluteAddressLoadInstruction",

vadl/main/vadl/lcb/template/lib/Target/EmitRegisterInfoCppFilePass.java

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText : © 2025 TU Wien <vadl@tuwien.ac.at>
+// SPDX-FileCopyrightText : © 2025-2026 TU Wien <vadl@tuwien.ac.at>
 // SPDX-License-Identifier: GPL-3.0-or-later
 //
 // This program is free software: you can redistribute it and/or modify
@@ -124,8 +124,8 @@ protected Map<String, Object> createVariables(final PassResults passResults,
         "returnAddress", abi.returnAddress().render(),
         "stackPointer", abi.stackPointer().render(),
         "hasThreadPointer", abi.threadPointer().isPresent(),
-        "threadPointer", abi.threadPointer().map(Abi.RegisterRef::render).orElse(""),
-        "globalPointer", abi.globalPointer().map(Abi.RegisterRef::render).orElse(""),
+        "threadPointer", abi.threadPointer().map(Abi.AbiRegister::render).orElse(""),
+        "globalPointer", abi.globalPointer().map(Abi.AbiRegister::render).orElse(""),
         "frameIndexEliminations",
         getEliminateFrameIndexEntries(instructionLabels, uninlined,
             tableGenMachineInstructions).stream()

vadl/main/vadl/lcb/template/lib/Target/EmitRegisterInfoTableGenFilePass.java

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText : © 2025 TU Wien <vadl@tuwien.ac.at>
+// SPDX-FileCopyrightText : © 2025-2026 TU Wien <vadl@tuwien.ac.at>
 // SPDX-License-Identifier: GPL-3.0-or-later
 //
 // This program is free software: you can redistribute it and/or modify
@@ -90,7 +90,7 @@ protected Map<String, Object> createVariables(final PassResults passResults,
 
     // The order of registers represents the preferred allocation sequence.
     // Registers are listed in the order caller-save, callee-save, specials.
-    var callerSaved = abi.callerSaved().stream().map(Abi.RegisterRef::render).toList();
+    var callerSaved = abi.callerSaved().stream().map(Abi.AbiRegister::render).toList();
     verifyAllTheSameRegisterFile(abi.callerSaved());
     verifyAllTheSameRegisterFile(abi.calleeSaved());
     verifyBothTheSame(abi.calleeSaved(), abi.callerSaved());
@@ -99,13 +99,13 @@ protected Map<String, Object> createVariables(final PassResults passResults,
     var exceptions = new HashSet<>(Stream.of(
         Optional.of(abi.returnAddress().render()),
         Optional.of(abi.stackPointer().render()),
-        abi.globalPointer().map(Abi.RegisterRef::render),
+        abi.globalPointer().map(Abi.AbiRegister::render),
         Optional.of(abi.framePointer().render()),
-        abi.threadPointer().map(Abi.RegisterRef::render)
+        abi.threadPointer().map(Abi.AbiRegister::render)
     ).filter(Optional::isPresent).map(Optional::get).toList());
 
     var calleeSaved = abi.calleeSaved().stream()
-        .map(Abi.RegisterRef::render)
+        .map(Abi.AbiRegister::render)
         .filter(render -> !exceptions.contains(render))
         .toList();
 
@@ -181,8 +181,8 @@ protected Map<String, Object> createVariables(final PassResults passResults,
     );
   }
 
-  private void verifyBothTheSame(List<Abi.RegisterRef> calleeSaved,
-                                 List<Abi.RegisterRef> callerSaved) {
+  private void verifyBothTheSame(List<Abi.AbiRegister> calleeSaved,
+                                 List<Abi.AbiRegister> callerSaved) {
     if (!callerSaved.isEmpty() && !calleeSaved.isEmpty()) {
       var callerRegFile = getRegisterFile(callerSaved.getFirst().registerFile());
       var calleeRegFile = getRegisterFile(calleeSaved.getFirst().registerFile());
@@ -206,13 +206,13 @@ private Resource getRegisterFile(RegisterResource registerResource) {
     return registerResource;
   }
 
-  private void verifyAllTheSameRegisterFile(List<Abi.RegisterRef> registerRefs) {
+  private void verifyAllTheSameRegisterFile(List<Abi.AbiRegister> registerRefs) {
     var set = registerRefs.stream().map(ref -> getRegisterFile(ref.registerFile()))
         .collect(Collectors.toSet());
 
     if (set.size() > 1) {
       throw Diagnostic.error("All register must have the same register file.",
-          registerRefs.stream().map(Abi.RegisterRef::location)
+          registerRefs.stream().map(Abi.AbiRegister::location)
               .reduce(registerRefs.get(0).location(),
                   SourceLocation::join).location()).build();
     }

vadl/main/vadl/viam/Abi.java

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText : © 2025 TU Wien <vadl@tuwien.ac.at>
+// SPDX-FileCopyrightText : © 2025-2026 TU Wien <vadl@tuwien.ac.at>
 // SPDX-License-Identifier: GPL-3.0-or-later
 //
 // This program is free software: you can redistribute it and/or modify
@@ -21,6 +21,7 @@
 import java.util.Optional;
 import vadl.utils.Pair;
 import vadl.utils.SourceLocation;
+import vadl.utils.WithLocation;
 
 /**
  * VADL ABI representation.
@@ -190,19 +191,47 @@ public ClangType(ClangType.TypeName typeName, ClangType.TypeSize size, SourceLoc
   }
 
   /**
-   * Constructor.
+   * ABI-specific register role.
    *
-   * @param registerFile is the "parent" of the register.
-   * @param addr         represents the index in a register file.
-   *                     E.g., RISC-V's X11 would have {@code addr = 11}.
-   * @param alignment    for the spilling of the register.
+   * @param registerRef semantic register reference
+   * @param alignment   for the spilling of the register
    */
-  public record RegisterRef(RegisterResource registerFile,
-                            int addr,
-                            Alignment alignment,
-                            SourceLocation location) {
+  public record AbiRegister(RegisterRef registerRef,
+                            Alignment alignment) implements WithLocation {
+
+    /**
+     * Constructs an ABI register role from the historical single-index representation.
+     */
+    public AbiRegister(RegisterResource registerFile,
+                       int addr,
+                       Alignment alignment,
+                       SourceLocation location) {
+      this(new RegisterRef(registerFile,
+          List.of(Constant.Value.of(addr, registerFile.indexTypes().getFirst())),
+          location), alignment);
+    }
+
+    public RegisterResource registerFile() {
+      return registerRef.resource();
+    }
+
+    public int addr() {
+      return registerRef.singleIndex();
+    }
+
+    @Override
+    public SourceLocation location() {
+      return registerRef.location();
+    }
+
+    /**
+     * Render the compiler register name.
+     *
+     * <p>This is kept temporarily for the existing LCB emitters. Rendering should move to the
+     * respective backend later.</p>
+     */
     public String render() {
-      return registerFile.generateRegisterFileName(addr);
+      return registerFile().generateRegisterFileName(addr());
     }
   }
 
@@ -213,18 +242,18 @@ public record RegisterAlias(String value) {
   }
 
 
-  private final RegisterRef returnAddress;
-  private final RegisterRef stackPointer;
-  private final Optional<RegisterRef> globalPointer;
-  private final RegisterRef framePointer;
-  private final Optional<RegisterRef> threadPointer;
+  private final AbiRegister returnAddress;
+  private final AbiRegister stackPointer;
+  private final Optional<AbiRegister> globalPointer;
+  private final AbiRegister framePointer;
+  private final Optional<AbiRegister> threadPointer;
 
 
   private final Map<Pair<RegisterResource, Integer>, List<RegisterAlias>> aliases;
-  private final List<RegisterRef> callerSaved;
-  private final List<RegisterRef> calleeSaved;
-  private final List<RegisterRef> argumentRegisters;
-  private final List<List<RegisterRef>> returnRegisters;
+  private final List<AbiRegister> callerSaved;
+  private final List<AbiRegister> calleeSaved;
+  private final List<AbiRegister> argumentRegisters;
+  private final List<List<AbiRegister>> returnRegisters;
   private final PrintableInstruction returnSequence;
   private final PrintableInstruction callSequence;
   private final Optional<PrintableInstruction> localAddressLoad;
@@ -248,16 +277,16 @@ public record RegisterAlias(String value) {
    * Constructor.
    */
   public Abi(Identifier identifier,
-             RegisterRef returnAddress,
-             RegisterRef stackPointer,
-             RegisterRef framePointer,
-             Optional<RegisterRef> globalPointer,
-             Optional<RegisterRef> threadPointer,
+             AbiRegister returnAddress,
+             AbiRegister stackPointer,
+             AbiRegister framePointer,
+             Optional<AbiRegister> globalPointer,
+             Optional<AbiRegister> threadPointer,
              Map<Pair<RegisterResource, Integer>, List<RegisterAlias>> aliases,
-             List<RegisterRef> callerSaved,
-             List<RegisterRef> calleeSaved,
-             List<RegisterRef> argumentRegisters,
-             List<List<RegisterRef>> returnRegisters,
+             List<AbiRegister> callerSaved,
+             List<AbiRegister> calleeSaved,
+             List<AbiRegister> argumentRegisters,
+             List<List<AbiRegister>> returnRegisters,
              PrintableInstruction returnSequence,
              PrintableInstruction callSequence,
              Optional<PrintableInstruction> localAddressLoad,
@@ -300,43 +329,43 @@ public void accept(DefinitionVisitor visitor) {
   }
 
 
-  public RegisterRef returnAddress() {
+  public AbiRegister returnAddress() {
     return returnAddress;
   }
 
-  public RegisterRef stackPointer() {
+  public AbiRegister stackPointer() {
     return stackPointer;
   }
 
-  public RegisterRef framePointer() {
+  public AbiRegister framePointer() {
     return framePointer;
   }
 
-  public Optional<RegisterRef> globalPointer() {
+  public Optional<AbiRegister> globalPointer() {
     return globalPointer;
   }
 
-  public Optional<RegisterRef> threadPointer() {
+  public Optional<AbiRegister> threadPointer() {
     return threadPointer;
   }
 
   public Map<Pair<RegisterResource, Integer>, List<RegisterAlias>> aliases() {
     return aliases;
   }
 
-  public List<RegisterRef> callerSaved() {
+  public List<AbiRegister> callerSaved() {
     return callerSaved;
   }
 
-  public List<RegisterRef> calleeSaved() {
+  public List<AbiRegister> calleeSaved() {
     return calleeSaved;
   }
 
-  public List<RegisterRef> argumentRegisters() {
+  public List<AbiRegister> argumentRegisters() {
     return argumentRegisters;
   }
 
-  public List<List<RegisterRef>> returnRegisters() {
+  public List<List<AbiRegister>> returnRegisters() {
     return returnRegisters;
   }