[llvm] JITLink: Add initial SystemZ Support. (PR #144528)

[Ulrich Weigand via llvm-commits]

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+//=== systemz.h - Generic JITLink systemz edge kinds, utilities -*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Generic utilities for graphs representing systemz objects.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_EXECUTIONENGINE_JITLINK_SYSTEMZ_H
+#define LLVM_EXECUTIONENGINE_JITLINK_SYSTEMZ_H
+
+#include "TableManager.h"
+#include "llvm/ExecutionEngine/JITLink/JITLink.h"
+
+using namespace llvm::support::endian;
+
+namespace llvm {
+namespace jitlink {
+namespace systemz {
+
+/// Represents systemz fixups and other systemz-specific edge kinds.
+enum EdgeKind_systemz : Edge::Kind {
+
+  /// A plain 64-bit pointer value relocation.
+  ///
+  /// Fixup expression:
+  ///   Fixup <- Target + Addend : uint64
+  ///
+  Pointer64 = Edge::FirstRelocation,
+
+  /// A plain 32-bit pointer value relocation.
+  ///
+  /// Fixup expression:
+  ///   Fixup <- Target + Addend : uint32
+  ///
+  /// Errors:
+  ///   - The target must reside in the low 32-bits of the address space,
+  ///     otherwise an out-of-range error will be returned.
+  ///
+  Pointer32,
+
+  /// A plain 20-bit pointer value relocation.
+  ///
+  /// Fixup expression:
+  ///   Fixup <- Target + Addend : uint20
+  ///
+  /// Errors:
+  ///   - The target must reside in the low 20-bits of the address space,
+  ///     otherwise an out-of-range error will be returned.
+  ///
+  Pointer20,
+
+  /// A plain 16-bit pointer value relocation.
+  ///
+  /// Fixup expression:
+  ///   Fixup <- Target + Addend : uint16
+  ///
+  /// Errors:
+  ///   - The target must reside in the low 16-bits of the address space,
+  ///     otherwise an out-of-range error will be returned.
+  ///
+  Pointer16,
+
+  /// A plain 12-bit pointer value relocation.
+  ///
+  /// Fixup expression:
+  ///   Fixup <- Target + Addend : uint12
+  ///
+  /// Errors:
+  ///   - The target must reside in the low 12-bits of the address space,
+  ///     otherwise an out-of-range error will be returned.
+  ///
+  Pointer12,
+
+  /// A plain 8-bit pointer value relocation.
+  ///
+  /// Fixup expression:
+  ///   Fixup <- Target + Addend : uint8
+  ///
+  /// Errors:
+  ///   - The target must reside in the low 8-bits of the address space,
+  ///     otherwise an out-of-range error will be returned.
+  ///
+  Pointer8,
+
+  /// A 64-bit delta.
+  ///
+  /// Delta from the fixup to the target.
+  ///
+  /// Fixup expression:
+  ///   Fixup <- Target - Fixup + Addend : int64
+  ///
+  Delta64,
+
+  /// A 32-bit delta.
+  ///
+  /// Delta from the fixup to the target.
+  ///
+  /// Fixup expression:
+  ///   Fixup <- Target - Fixup + Addend : int32
+  ///
+  /// Errors:
+  ///   - The result of the fixup expression must fit into an int32, otherwise
+  ///     an out-of-range error will be returned.
+  ///
+  Delta32,
+
+  /// A 16-bit delta.
+  ///
+  /// Delta from the fixup to the target.
+  ///
+  /// Fixup expression:
+  ///   Fixup <- Target - Fixup + Addend : int16
+  ///
+  /// Errors:
+  ///   - The result of the fixup expression must fit into an int16, otherwise
+  ///     an out-of-range error will be returned.
+  ///
+  Delta16,
+
+  /// A 32-bit delta.
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uweigand wrote:

Like the variants further down, this should mention "shifted by 1" in the description.  Similar for the next few variants.

https://github.com/llvm/llvm-project/pull/144528