[llvm] r278149 - Re-apply r278065 (Weak symbol support in RuntimeDyld) with a fix for ELF.

[Lang Hames via llvm-commits]

Author: lhames
Date: Tue Aug  9 14:27:17 2016
New Revision: 278149

URL: http://llvm.org/viewvc/llvm-project?rev=278149&view=rev
Log:
Re-apply r278065 (Weak symbol support in RuntimeDyld) with a fix for ELF.

Added:
    llvm/trunk/test/ExecutionEngine/MCJIT/Inputs/weak-function-2.ll
      - copied unchanged from r278068, llvm/trunk/test/ExecutionEngine/MCJIT/Inputs/weak-function-2.ll
    llvm/trunk/test/ExecutionEngine/MCJIT/weak-function.ll
      - copied unchanged from r278068, llvm/trunk/test/ExecutionEngine/MCJIT/weak-function.ll
    llvm/trunk/test/ExecutionEngine/OrcMCJIT/Inputs/weak-function-2.ll
      - copied unchanged from r278068, llvm/trunk/test/ExecutionEngine/OrcMCJIT/Inputs/weak-function-2.ll
    llvm/trunk/test/ExecutionEngine/OrcMCJIT/weak-function.ll
      - copied unchanged from r278068, llvm/trunk/test/ExecutionEngine/OrcMCJIT/weak-function.ll
Modified:
    llvm/trunk/lib/ExecutionEngine/Orc/OrcMCJITReplacement.h
    llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
    llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp

Modified: llvm/trunk/lib/ExecutionEngine/Orc/OrcMCJITReplacement.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/Orc/OrcMCJITReplacement.h?rev=278149&r1=278148&r2=278149&view=diff
==============================================================================
--- llvm/trunk/lib/ExecutionEngine/Orc/OrcMCJITReplacement.h (original)
+++ llvm/trunk/lib/ExecutionEngine/Orc/OrcMCJITReplacement.h Tue Aug  9 14:27:17 2016
@@ -116,11 +116,13 @@ class OrcMCJITReplacement : public Execu
     LinkingResolver(OrcMCJITReplacement &M) : M(M) {}
 
     JITSymbol findSymbol(const std::string &Name) override {
-      return M.findMangledSymbol(Name);
+      return M.ClientResolver->findSymbol(Name);
     }
 
     JITSymbol findSymbolInLogicalDylib(const std::string &Name) override {
-      return M.ClientResolver->findSymbol(Name);
+      if (auto Sym = M.findMangledSymbol(Name))
+        return Sym;
+      return M.ClientResolver->findSymbolInLogicalDylib(Name);
     }
 
   private:

Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp?rev=278149&r1=278148&r2=278149&view=diff
==============================================================================
--- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp (original)
+++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp Tue Aug  9 14:27:17 2016
@@ -226,6 +226,24 @@ RuntimeDyldImpl::loadObjectImpl(const ob
       // Compute JIT symbol flags.
       JITSymbolFlags JITSymFlags = JITSymbolFlags::fromObjectSymbol(*I);
 
+      // If this is a weak definition, check to see if there's a strong one.
+      // If there is, skip this symbol (we won't be providing it: the strong
+      // definition will). If there's no strong definition, make this definition
+      // strong.
+      if (JITSymFlags.isWeak()) {
+        // First check whether there's already a definition in this instance.
+        // FIXME: Override existing weak definitions with strong ones.
+        if (GlobalSymbolTable.count(Name))
+          continue;
+        // Then check the symbol resolver to see if there's a definition
+        // elsewhere in this logical dylib.
+        if (auto Sym = Resolver.findSymbolInLogicalDylib(Name))
+          if (Sym.getFlags().isStrongDefinition())
+            continue;
+        // else
+        JITSymFlags &= ~JITSymbolFlags::Weak;
+      }
+
       if (Flags & SymbolRef::SF_Absolute &&
           SymType != object::SymbolRef::ST_File) {
         uint64_t Addr = 0;

Modified: llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp?rev=278149&r1=278148&r2=278149&view=diff
==============================================================================
--- llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp (original)
+++ llvm/trunk/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp Tue Aug  9 14:27:17 2016
@@ -1258,6 +1258,7 @@ RuntimeDyldELF::processRelocationRef(
       break;
     }
     case SymbolRef::ST_Data:
+    case SymbolRef::ST_Function:
     case SymbolRef::ST_Unknown: {
       Value.SymbolName = TargetName.data();
       Value.Addend = Addend;