From 96bdb6594ca63946e9755aec25d42dfd904d0e97 Mon Sep 17 00:00:00 2001
From: Lang Hames <lhames@gmail.com>
Date: Wed, 1 Apr 2015 04:42:56 +0000
Subject: [PATCH] [Orc] Reflect process symbols into the LLI Orc-lazy JIT.

This makes symbol resolution essentially identical between MCJIT and the LLI
Orc-lazy JIT.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233786 91177308-0d34-0410-b5e6-96231b3b80d8
---
 tools/lli/OrcLazyJIT.cpp | 13 +++++++++++++
 tools/lli/OrcLazyJIT.h   |  9 ++++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/tools/lli/OrcLazyJIT.cpp b/tools/lli/OrcLazyJIT.cpp
index 0e4e2a579b6..d08008da6e0 100644
--- a/tools/lli/OrcLazyJIT.cpp
+++ b/tools/lli/OrcLazyJIT.cpp
@@ -9,6 +9,7 @@
 
 #include "OrcLazyJIT.h"
 #include "llvm/ExecutionEngine/Orc/OrcTargetSupport.h"
+#include "llvm/Support/DynamicLibrary.h"
 
 using namespace llvm;
 
@@ -29,19 +30,31 @@ OrcLazyJIT::createCallbackManagerBuilder(Triple T) {
 }
 
 int llvm::runOrcLazyJIT(std::unique_ptr<Module> M, int ArgC, char* ArgV[]) {
+  // Add the program's symbols into the JIT's search space.
+  if (sys::DynamicLibrary::LoadLibraryPermanently(nullptr)) {
+    errs() << "Error loading program symbols.\n";
+    return 1;
+  }
+
+  // Grab a target machine and try to build a factory function for the
+  // target-specific Orc callback manager.
   auto TM = std::unique_ptr<TargetMachine>(EngineBuilder().selectTarget());
   auto &Context = getGlobalContext();
   auto CallbackMgrBuilder =
     OrcLazyJIT::createCallbackManagerBuilder(Triple(TM->getTargetTriple()));
 
+  // If we couldn't build the factory function then there must not be a callback
+  // manager for this target. Bail out.
   if (!CallbackMgrBuilder) {
     errs() << "No callback manager available for target '"
            << TM->getTargetTriple() << "'.\n";
     return 1;
   }
 
+  // Everything looks good. Build the JIT.
   OrcLazyJIT J(std::move(TM), Context, CallbackMgrBuilder);
 
+  // Add the module, look up main and run it.
   auto MainHandle = J.addModule(std::move(M));
   auto MainSym = J.findSymbolIn(MainHandle, "main");
 
diff --git a/tools/lli/OrcLazyJIT.h b/tools/lli/OrcLazyJIT.h
index 89dfa6ba927..e323714646b 100644
--- a/tools/lli/OrcLazyJIT.h
+++ b/tools/lli/OrcLazyJIT.h
@@ -21,6 +21,7 @@
 #include "llvm/ExecutionEngine/Orc/IRCompileLayer.h"
 #include "llvm/ExecutionEngine/Orc/LazyEmittingLayer.h"
 #include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h"
+#include "llvm/ExecutionEngine/RTDyldMemoryManager.h"
 #include "llvm/IR/LLVMContext.h"
 
 namespace llvm {
@@ -61,7 +62,13 @@ public:
 
     std::vector<std::unique_ptr<Module>> S;
     S.push_back(std::move(M));
-    return CODLayer.addModuleSet(std::move(S));
+    auto FallbackLookup =
+      [](const std::string &Name) {
+        if (auto Addr = RTDyldMemoryManager::getSymbolAddressInProcess(Name))
+          return RuntimeDyld::SymbolInfo(Addr, JITSymbolFlags::Exported);
+        return RuntimeDyld::SymbolInfo(nullptr);
+      };
+    return CODLayer.addModuleSet(std::move(S), std::move(FallbackLookup));
   }
 
   orc::JITSymbol findSymbol(const std::string &Name) {