[JITLink][ORC] Add EHFrameRegistrar interface, use in EHFrameRegistrationPlugin.

Replaces direct calls to eh-frame registration with calls to methods on an
EHFrameRegistrar instance. This allows clients to substitute a registrar that
registers frames in a remote process via IPC/RPC.

llvm-svn: 365098

include/llvm/ExecutionEngine/JITLink/EHFrameSupport.h

@@ -27,6 +27,41 @@ Error registerEHFrameSection(const void *EHFrameSectionAddr);
 /// Deregisters all FDEs in the given eh-frame section with the current process.
 Error deregisterEHFrameSection(const void *EHFrameSectionAddr);
 
+/// Supports registration/deregistration of EH-frames in a target process.
+class EHFrameRegistrar {
+public:
+  virtual ~EHFrameRegistrar();
+  virtual Error registerEHFrames(JITTargetAddress EHFrameSectionAddr) = 0;
+  virtual Error deregisterEHFrames(JITTargetAddress EHFrameSectionAddr) = 0;
+};
+
+/// Registers / Deregisters EH-frames in the current process.
+class InProcessEHFrameRegistrar final : public EHFrameRegistrar {
+public:
+  /// Get a reference to the InProcessEHFrameRegistrar singleton.
+  static InProcessEHFrameRegistrar &getInstance();
+
+  InProcessEHFrameRegistrar(const InProcessEHFrameRegistrar &) = delete;
+  InProcessEHFrameRegistrar &
+  operator=(const InProcessEHFrameRegistrar &) = delete;
+
+  InProcessEHFrameRegistrar(InProcessEHFrameRegistrar &&) = delete;
+  InProcessEHFrameRegistrar &operator=(InProcessEHFrameRegistrar &&) = delete;
+
+  Error registerEHFrames(JITTargetAddress EHFrameSectionAddr) override {
+    return registerEHFrameSection(
+        jitTargetAddressToPointer<void *>(EHFrameSectionAddr));
+  }
+
+  Error deregisterEHFrames(JITTargetAddress EHFrameSectionAddr) override {
+    return deregisterEHFrameSection(
+        jitTargetAddressToPointer<void *>(EHFrameSectionAddr));
+  }
+
+private:
+  InProcessEHFrameRegistrar();
+};
+
 using StoreFrameAddressFunction = std::function<void(JITTargetAddress)>;
 
 /// Creates a pass that records the address of the EH frame section. If no

include/llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h

@@ -33,6 +33,10 @@
 
 namespace llvm {
 
+namespace jitlink {
+class EHFrameRegistrar;
+} // namespace jitlink
+
 namespace object {
 class ObjectFile;
 } // namespace object
@@ -139,8 +143,9 @@ private:
   std::vector<std::unique_ptr<Plugin>> Plugins;
 };
 
-class LocalEHFrameRegistrationPlugin : public ObjectLinkingLayer::Plugin {
+class EHFrameRegistrationPlugin : public ObjectLinkingLayer::Plugin {
 public:
+  EHFrameRegistrationPlugin(jitlink::EHFrameRegistrar &Registrar);
   Error notifyEmitted(MaterializationResponsibility &MR) override;
   void modifyPassConfig(MaterializationResponsibility &MR, const Triple &TT,
                         jitlink::PassConfiguration &PassConfig) override;
@@ -148,9 +153,10 @@ public:
   Error notifyRemovingAllModules() override;
 
 private:
-  DenseMap<MaterializationResponsibility *, const void *> InProcessLinks;
+  jitlink::EHFrameRegistrar &Registrar;
-  DenseMap<VModuleKey, const void *> TrackedEHFrameAddrs;
+  DenseMap<MaterializationResponsibility *, JITTargetAddress> InProcessLinks;
-  std::vector<const void *> UntrackedEHFrameAddrs;
+  DenseMap<VModuleKey, JITTargetAddress> TrackedEHFrameAddrs;
+  std::vector<JITTargetAddress> UntrackedEHFrameAddrs;
 };
 
 } // end namespace orc

lib/ExecutionEngine/JITLink/EHFrameSupport.cpp

@@ -508,6 +508,15 @@ Error deregisterEHFrameSection(const void *EHFrameSectionAddr) {
 #endif
 }
 
+EHFrameRegistrar::~EHFrameRegistrar() {}
+
+InProcessEHFrameRegistrar &InProcessEHFrameRegistrar::getInstance() {
+  static InProcessEHFrameRegistrar Instance;
+  return Instance;
+}
+
+InProcessEHFrameRegistrar::InProcessEHFrameRegistrar() {}
+
 AtomGraphPassFunction
 createEHFrameRecorderPass(const Triple &TT,
                           StoreFrameAddressFunction StoreFrameAddress) {

lib/ExecutionEngine/Orc/ObjectLinkingLayer.cpp

@@ -409,7 +409,11 @@ Error ObjectLinkingLayer::removeAllModules() {
   return Err;
 }
 
-void LocalEHFrameRegistrationPlugin::modifyPassConfig(
+EHFrameRegistrationPlugin::EHFrameRegistrationPlugin(
+    jitlink::EHFrameRegistrar &Registrar)
+    : Registrar(Registrar) {}
+
+void EHFrameRegistrationPlugin::modifyPassConfig(
     MaterializationResponsibility &MR, const Triple &TT,
     PassConfiguration &PassConfig) {
   assert(!InProcessLinks.count(&MR) && "Link for MR already being tracked?");
@@ -417,18 +421,18 @@ void LocalEHFrameRegistrationPlugin::modifyPassConfig(
   PassConfig.PostFixupPasses.push_back(
       createEHFrameRecorderPass(TT, [this, &MR](JITTargetAddress Addr) {
         if (Addr)
-          InProcessLinks[&MR] = jitTargetAddressToPointer<void *>(Addr);
+          InProcessLinks[&MR] = Addr;
       }));
 }
 
-Error LocalEHFrameRegistrationPlugin::notifyEmitted(
+Error EHFrameRegistrationPlugin::notifyEmitted(
     MaterializationResponsibility &MR) {
 
   auto EHFrameAddrItr = InProcessLinks.find(&MR);
   if (EHFrameAddrItr == InProcessLinks.end())
     return Error::success();
 
-  const void *EHFrameAddr = EHFrameAddrItr->second;
+  auto EHFrameAddr = EHFrameAddrItr->second;
   assert(EHFrameAddr && "eh-frame addr to register can not be null");
 
   InProcessLinks.erase(EHFrameAddrItr);
@@ -437,25 +441,25 @@ Error LocalEHFrameRegistrationPlugin::notifyEmitted(
   else
     UntrackedEHFrameAddrs.push_back(EHFrameAddr);
 
-  return registerEHFrameSection(EHFrameAddr);
+  return Registrar.registerEHFrames(EHFrameAddr);
 }
 
-Error LocalEHFrameRegistrationPlugin::notifyRemovingModule(VModuleKey K) {
+Error EHFrameRegistrationPlugin::notifyRemovingModule(VModuleKey K) {
   auto EHFrameAddrItr = TrackedEHFrameAddrs.find(K);
   if (EHFrameAddrItr == TrackedEHFrameAddrs.end())
     return Error::success();
 
-  const void *EHFrameAddr = EHFrameAddrItr->second;
+  auto EHFrameAddr = EHFrameAddrItr->second;
   assert(EHFrameAddr && "Tracked eh-frame addr must not be null");
 
   TrackedEHFrameAddrs.erase(EHFrameAddrItr);
 
-  return deregisterEHFrameSection(EHFrameAddr);
+  return Registrar.deregisterEHFrames(EHFrameAddr);
 }
 
-Error LocalEHFrameRegistrationPlugin::notifyRemovingAllModules() {
+Error EHFrameRegistrationPlugin::notifyRemovingAllModules() {
 
-  std::vector<const void *> EHFrameAddrs = std::move(UntrackedEHFrameAddrs);
+  std::vector<JITTargetAddress> EHFrameAddrs = std::move(UntrackedEHFrameAddrs);
   EHFrameAddrs.reserve(EHFrameAddrs.size() + TrackedEHFrameAddrs.size());
 
   for (auto &KV : TrackedEHFrameAddrs)
@@ -466,10 +470,10 @@ Error LocalEHFrameRegistrationPlugin::notifyRemovingAllModules() {
   Error Err = Error::success();
 
   while (!EHFrameAddrs.empty()) {
-    const void *EHFrameAddr = EHFrameAddrs.back();
+    auto EHFrameAddr = EHFrameAddrs.back();
     assert(EHFrameAddr && "Untracked eh-frame addr must not be null");
     EHFrameAddrs.pop_back();
-    Err = joinErrors(std::move(Err), deregisterEHFrameSection(EHFrameAddr));
+    Err = joinErrors(std::move(Err), Registrar.deregisterEHFrames(EHFrameAddr));
   }
 
   return Err;

tools/llvm-jitlink/llvm-jitlink.cpp

@@ -14,6 +14,7 @@
 
 #include "llvm-jitlink.h"
 
+#include "llvm/ExecutionEngine/JITLink/EHFrameSupport.h"
 #include "llvm/ExecutionEngine/Orc/ExecutionUtils.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCContext.h"
@@ -232,7 +233,8 @@ Session::Session(Triple TT) : ObjLayer(ES, MemMgr), TT(std::move(TT)) {
   };
 
   if (!NoExec && !TT.isOSWindows())
-    ObjLayer.addPlugin(llvm::make_unique<LocalEHFrameRegistrationPlugin>());
+    ObjLayer.addPlugin(llvm::make_unique<EHFrameRegistrationPlugin>(
+        InProcessEHFrameRegistrar::getInstance()));
 
   ObjLayer.addPlugin(llvm::make_unique<JITLinkSessionPlugin>(*this));
 }