[Orc] Initial version of ELFSymtabStaticGenerator

llvm/include/llvm/ExecutionEngine/Orc/ELFStaticSymtabGenerator.h

@@ -0,0 +1,26 @@
+#ifndef LLVM_EXECUTIONENGINE_ORC_ELFSTATICSYMTABGENERATOR_H
+#define LLVM_EXECUTIONENGINE_ORC_ELFSTATICSYMTABGENERATOR_H
+
+#include "llvm/ADT/FunctionExtras.h"
+#include "llvm/ExecutionEngine/Orc/Core.h"
+#include "llvm/ExecutionEngine/Orc/Mangling.h"
+
+namespace llvm {
+namespace orc {
+
+class ELFStaticSymtabGenerator : public DefinitionGenerator {
+public:
+  ELFStaticSymtabGenerator(ExecutionSession &ES);
+
+  Error tryToGenerate(LookupState &LS, LookupKind K, JITDylib &JD,
+                      JITDylibLookupFlags JDLookupFlags,
+                      const SymbolLookupSet &Symbols) override;
+private:
+  ExecutionSession &ES;
+  std::map<SymbolStringPtr, JITTargetAddress> StaticSymbols;
+};
+
+} // end namespace orc
+} // end namespace llvm
+
+#endif // LLVM_EXECUTIONENGINE_ORC_ELFSTATICSYMTABGENERATOR_H

llvm/lib/ExecutionEngine/Orc/ELFStaticSymtabGenerator.cpp

@@ -0,0 +1,78 @@
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/ExecutionEngine/Orc/ELFStaticSymtabGenerator.h"
+#include "llvm/ExecutionEngine/Orc/ExecutionUtils.h"
+#include "llvm/ExecutionEngine/Orc/DebugUtils.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Error.h"
+
+#define DEBUG_TYPE "orc"
+
+namespace llvm {
+namespace orc {
+
+ELFStaticSymtabGenerator::ELFStaticSymtabGenerator(ExecutionSession &ES) : ES(ES) {
+  auto MBOrErr = MemoryBuffer::getFile("/proc/self/exe");
+  if (!MBOrErr) {
+    return;
+  }
+  std::unique_ptr<MemoryBuffer> MB = std::move(MBOrErr.get());
+  auto ObjOrErr = object::ObjectFile::createObjectFile(MB->getMemBufferRef());
+  if (!ObjOrErr) {
+    consumeError(ObjOrErr.takeError());
+    return;
+  }
+  auto *Obj = ObjOrErr->get();
+
+  for (const auto &Sym : Obj->symbols()) {
+    Expected<StringRef> NameOrErr = Sym.getName();
+    if (!NameOrErr) {
+      consumeError(NameOrErr.takeError());
+      continue;
+    }
+    StringRef Name = *NameOrErr;
+
+    // Retrieve the symbol flags.
+    Expected<uint32_t> FlagsOrErr = Sym.getFlags();
+    if (!FlagsOrErr) {
+      consumeError(FlagsOrErr.takeError());
+      continue;
+    }
+    uint32_t Flags = *FlagsOrErr;
+
+    // Only add symbols that are defined.
+    if (!(Flags & object::BasicSymbolRef::SF_Undefined)) {
+      Expected<uint64_t> AddrOrErr = Sym.getAddress();
+      if (!AddrOrErr) {
+        consumeError(AddrOrErr.takeError());
+        continue;
+      }
+      JITTargetAddress Addr = *AddrOrErr;
+      // Intern the symbol name using the ExecutionSession's symbol pool.
+      SymbolStringPtr SSP = ES.getSymbolStringPool()->intern(Name);
+      StaticSymbols[SSP] = Addr;
+    }
+  }
+}
+
+Error ELFStaticSymtabGenerator::tryToGenerate(LookupState &LS, LookupKind K,
+                                              JITDylib &JD,
+                                              JITDylibLookupFlags JDLookupFlags,
+                                              const SymbolLookupSet &Symbols) {
+
+  SymbolMap NewSymbols;
+  for (auto &KV : Symbols) {
+    SymbolStringPtr Name = KV.first;
+    if (auto It = StaticSymbols.find(Name); It != StaticSymbols.end()) {
+      JITEvaluatedSymbol Sym(It->second, JITSymbolFlags::Exported);
+      NewSymbols[Name] = ExecutorSymbolDef(ExecutorAddr(It->second), JITSymbolFlags::Exported);
+    }
+  }
+  // If any symbols were found, add them to the JITDylib.
+  if (!NewSymbols.empty())
+    return JD.define(absoluteSymbols(std::move(NewSymbols)));
+  return Error::success();
+}
+
+} // end namespace orc
+} // end namespace llvm
+