[compiler-rt] [llvm] [ORC] Implement basic reoptimization. (PR #67050)

[Lang Hames via llvm-commits]

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@@ -0,0 +1,106 @@
+//===- JITLinkRedirectableSymbolManager.h - JITLink redirection -*- 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Redirectable Symbol Manager implementation using JITLink
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_EXECUTIONENGINE_ORC_JITLINKREDIRECABLEMANAGER_H
+#define LLVM_EXECUTIONENGINE_ORC_JITLINKREDIRECABLEMANAGER_H
+
+#include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h"
+#include "llvm/ExecutionEngine/Orc/RedirectionManager.h"
+#include "llvm/Support/StringSaver.h"
+
+namespace llvm {
+namespace orc {
+
+class JITLinkRedirectableSymbolManager : public RedirectableSymbolManager,
+                                         public ResourceManager {
+public:
+  /// Create redirection manager that uses JITLink based implementaion.
+  static Expected<std::unique_ptr<RedirectableSymbolManager>>
+  Create(ExecutionSession &ES, ObjectLinkingLayer &ObjLinkingLayer,
+         JITDylib &JD) {
+    Error Err = Error::success();
+    auto RM = std::unique_ptr<RedirectableSymbolManager>(
+        new JITLinkRedirectableSymbolManager(ES, ObjLinkingLayer, JD, Err));
+    if (Err)
+      return Err;
+    return std::move(RM);
+  }
+
+  void emitRedirectableSymbols(std::unique_ptr<MaterializationResponsibility> R,
+                               const SymbolAddrMap &InitialDests) override;
+
+  Error redirect(JITDylib &TargetJD, const SymbolAddrMap &NewDests) override;
+
+  Error handleRemoveResources(JITDylib &TargetJD, ResourceKey K) override;
+
+  void handleTransferResources(JITDylib &TargetJD, ResourceKey DstK,
+                               ResourceKey SrcK) override;
+
+private:
+  using StubHandle = unsigned;
+  constexpr static unsigned StubBlockSize = 256;
+  constexpr static StringRef JumpStubPrefix = "$__IND_JUMP_STUBS";
+  constexpr static StringRef StubPtrPrefix = "$IND_JUMP_PTR_";
+  constexpr static StringRef JumpStubTableName = "$IND_JUMP_";
+  constexpr static StringRef StubPtrTableName = "$__IND_JUMP_PTRS";
+
+  JITLinkRedirectableSymbolManager(ExecutionSession &ES,
+                                   ObjectLinkingLayer &ObjLinkingLayer,
+                                   JITDylib &JD, Error &Err)
+      : ES(ES), ObjLinkingLayer(ObjLinkingLayer), JD(JD),
+        AnonymousPtrCreator(
+            jitlink::getAnonymousPointerCreator(ES.getTargetTriple())),
+        PtrJumpStubCreator(
+            jitlink::getPointerJumpStubCreator(ES.getTargetTriple())) {
+    if (!AnonymousPtrCreator || !PtrJumpStubCreator)
+      Err = make_error<StringError>("Architecture not supported",
+                                    inconvertibleErrorCode());
+    if (Err)
+      return;
+    ES.registerResourceManager(*this);
+  }
+
+  ~JITLinkRedirectableSymbolManager() { ES.deregisterResourceManager(*this); }
+
+  StringRef JumpStubSymbolName(unsigned I) {
+    return *ES.intern((JumpStubPrefix + Twine(I)).str());
+  }
+
+  StringRef StubPtrSymbolName(unsigned I) {
+    return *ES.intern((StubPtrPrefix + Twine(I)).str());
+  }
+
+  unsigned GetNumAvailableStubs() const { return AvailableStubs.size(); }
+
+  Error redirectInner(JITDylib &TargetJD, const SymbolAddrMap &NewDests);
+  Error grow(unsigned Need);
+
+  ExecutionSession &ES;
+  ObjectLinkingLayer &ObjLinkingLayer;
----------------
lhames wrote:

`ObjLinkingLayer` already has an `ExecutionSession` member that you could re-use to save a pointer here if you wanted.

https://github.com/llvm/llvm-project/pull/67050