gold plugin: Handle gold selecting a linkonce GV when a weak is present.

[oota-llvm.git] / tools / gold / gold-plugin.cpp

diff --git a/tools/gold/gold-plugin.cpp b/tools/gold/gold-plugin.cpp
index f2eeb7e8c4f1476dad6a78a488cb2f3b04a9f7e5..d5d58d0e5885884e9cdd9dc49cedb31c01887ed6 100644 (file)
--- a/tools/gold/gold-plugin.cpp
+++ b/tools/gold/gold-plugin.cpp
@@ -18,6 +18,7 @@
 #include "llvm/Bitcode/ReaderWriter.h"
 #include "llvm/CodeGen/Analysis.h"
 #include "llvm/CodeGen/CommandFlags.h"
+#include "llvm/IR/Constants.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Verifier.h"
@@ -299,7 +300,9 @@ static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
   ErrorOr<std::unique_ptr<object::IRObjectFile>> ObjOrErr =
       object::IRObjectFile::createIRObjectFile(BufferRef, Context);
   std::error_code EC = ObjOrErr.getError();
-  if (EC == BitcodeError::InvalidBitcodeSignature)
+  if (EC == BitcodeError::InvalidBitcodeSignature ||
+      EC == object::object_error::invalid_file_type ||
+      EC == object::object_error::bitcode_section_not_found)
     return LDPS_OK;
 
   *claimed = 1;
@@ -456,6 +459,7 @@ static void drop(GlobalValue &GV) {
                          /*Initializer*/ nullptr);
   Var->takeName(&Alias);
   Alias.replaceAllUsesWith(Var);
+  Alias.eraseFromParent();
 }
 
 static const char *getResolutionName(ld_plugin_symbol_resolution R) {
@@ -487,21 +491,36 @@ static GlobalObject *makeInternalReplacement(GlobalObject *GO) {
   Module *M = GO->getParent();
   GlobalObject *Ret;
   if (auto *F = dyn_cast<Function>(GO)) {
-    auto *NewF = Function::Create(
-        F->getFunctionType(), GlobalValue::InternalLinkage, F->getName(), M);
+    auto *NewF = Function::Create(F->getFunctionType(), F->getLinkage(),
+                                  F->getName(), M);
+
+    ValueToValueMapTy VM;
+    Function::arg_iterator NewI = NewF->arg_begin();
+    for (auto &Arg : F->args()) {
+      NewI->setName(Arg.getName());
+      VM[&Arg] = NewI;
+      ++NewI;
+    }
+
     NewF->getBasicBlockList().splice(NewF->end(), F->getBasicBlockList());
+    for (auto &BB : *NewF) {
+      for (auto &Inst : BB)
+        RemapInstruction(&Inst, VM, RF_IgnoreMissingEntries);
+    }
+
     Ret = NewF;
     F->deleteBody();
   } else {
     auto *Var = cast<GlobalVariable>(GO);
     Ret = new GlobalVariable(
         *M, Var->getType()->getElementType(), Var->isConstant(),
-        GlobalValue::InternalLinkage, Var->getInitializer(), Var->getName(),
+        Var->getLinkage(), Var->getInitializer(), Var->getName(),
         nullptr, Var->getThreadLocalMode(), Var->getType()->getAddressSpace(),
         Var->isExternallyInitialized());
     Var->setInitializer(nullptr);
   }
   Ret->copyAttributesFrom(GO);
+  Ret->setLinkage(GlobalValue::InternalLinkage);
   Ret->setComdat(GO->getComdat());
 
   return Ret;
@@ -546,8 +565,15 @@ getModuleForFile(LLVMContext &Context, claimed_file &F, raw_fd_ostream *ApiFile,
   if (get_view(F.handle, &View) != LDPS_OK)
     message(LDPL_FATAL, "Failed to get a view of file");
 
-  std::unique_ptr<MemoryBuffer> Buffer = MemoryBuffer::getMemBuffer(
-      StringRef((char *)View, File.filesize), "", false);
+  llvm::ErrorOr<MemoryBufferRef> MBOrErr =
+      object::IRObjectFile::findBitcodeInMemBuffer(
+          MemoryBufferRef(StringRef((const char *)View, File.filesize), ""));
+  if (std::error_code EC = MBOrErr.getError())
+    message(LDPL_FATAL, "Could not read bitcode from file : %s",
+            EC.message().c_str());
+
+  std::unique_ptr<MemoryBuffer> Buffer =
+      MemoryBuffer::getMemBuffer(MBOrErr->getBuffer(), "", false);
 
   if (release_input_file(F.handle) != LDPS_OK)
     message(LDPL_FATAL, "Failed to release file information");
@@ -576,6 +602,15 @@ getModuleForFile(LLVMContext &Context, claimed_file &F, raw_fd_ostream *ApiFile,
     if (!GV)
       continue; // Asm symbol.
 
+    if (Resolution != LDPR_PREVAILING_DEF_IRONLY && GV->hasCommonLinkage()) {
+      // Common linkage is special. There is no single symbol that wins the
+      // resolution. Instead we have to collect the maximum alignment and size.
+      // The IR linker does that for us if we just pass it every common GV.
+      // We still have to keep track of LDPR_PREVAILING_DEF_IRONLY so we
+      // internalize once the IR linker has done its job.
+      continue;
+    }
+
     switch (Resolution) {
     case LDPR_UNKNOWN:
       llvm_unreachable("Unexpected resolution");
@@ -602,8 +637,14 @@ getModuleForFile(LLVMContext &Context, claimed_file &F, raw_fd_ostream *ApiFile,
       keepGlobalValue(*GV, KeptAliases);
       break;
 
-    case LDPR_PREEMPTED_REG:
     case LDPR_PREEMPTED_IR:
+      // Gold might have selected a linkonce_odr and preempted a weak_odr.
+      // In that case we have to make sure we don't end up internalizing it.
+      if (!GV->isDiscardableIfUnused())
+        Maybe.erase(Sym.name);
+
+      // fall-through
+    case LDPR_PREEMPTED_REG:
       Drop.insert(GV);
       break;
 
@@ -684,7 +725,7 @@ static void codegen(Module &M) {
   runLTOPasses(M, *TM);
 
   PassManager CodeGenPasses;
-  CodeGenPasses.add(new DataLayoutPass(&M));
+  CodeGenPasses.add(new DataLayoutPass());
 
   SmallString<128> Filename;
   int FD;