1 files changed, 103 insertions, 1 deletions

diff --git a/contrib/llvm/lib/Transforms/Utils/ModuleUtils.cpp b/contrib/llvm/lib/Transforms/Utils/ModuleUtils.cpp
index eb91885..0d623df 100644
--- a/contrib/llvm/lib/Transforms/Utils/ModuleUtils.cpp
+++ b/contrib/llvm/lib/Transforms/Utils/ModuleUtils.cpp
@@ -89,6 +89,44 @@ void llvm::appendToGlobalDtors(Module &M, Function *F, int Priority, Constant *D
   appendToGlobalArray("llvm.global_dtors", M, F, Priority, Data);
 }
 
+static void appendToUsedList(Module &M, StringRef Name, ArrayRef<GlobalValue *> Values) {
+  GlobalVariable *GV = M.getGlobalVariable(Name);
+  SmallPtrSet<Constant *, 16> InitAsSet;
+  SmallVector<Constant *, 16> Init;
+  if (GV) {
+    ConstantArray *CA = dyn_cast<ConstantArray>(GV->getInitializer());
+    for (auto &Op : CA->operands()) {
+      Constant *C = cast_or_null<Constant>(Op);
+      if (InitAsSet.insert(C).second)
+        Init.push_back(C);
+    }
+    GV->eraseFromParent();
+  }
+
+  Type *Int8PtrTy = llvm::Type::getInt8PtrTy(M.getContext());
+  for (auto *V : Values) {
+    Constant *C = ConstantExpr::getBitCast(V, Int8PtrTy);
+    if (InitAsSet.insert(C).second)
+      Init.push_back(C);
+  }
+
+  if (Init.empty())
+    return;
+
+  ArrayType *ATy = ArrayType::get(Int8PtrTy, Init.size());
+  GV = new llvm::GlobalVariable(M, ATy, false, GlobalValue::AppendingLinkage,
+                                ConstantArray::get(ATy, Init), Name);
+  GV->setSection("llvm.metadata");
+}
+
+void llvm::appendToUsed(Module &M, ArrayRef<GlobalValue *> Values) {
+  appendToUsedList(M, "llvm.used", Values);
+}
+
+void llvm::appendToCompilerUsed(Module &M, ArrayRef<GlobalValue *> Values) {
+  appendToUsedList(M, "llvm.compiler.used", Values);
+}
+
 Function *llvm::checkSanitizerInterfaceFunction(Constant *FuncOrBitcast) {
   if (isa<Function>(FuncOrBitcast))
     return cast<Function>(FuncOrBitcast);
@@ -104,7 +142,7 @@ std::pair<Function *, Function *> llvm::createSanitizerCtorAndInitFunctions(
     ArrayRef<Type *> InitArgTypes, ArrayRef<Value *> InitArgs,
     StringRef VersionCheckName) {
   assert(!InitName.empty() && "Expected init function name");
-  assert(InitArgTypes.size() == InitArgTypes.size() &&
+  assert(InitArgs.size() == InitArgTypes.size() &&
          "Sanitizer's init function expects different number of arguments");
   Function *Ctor = Function::Create(
       FunctionType::get(Type::getVoidTy(M.getContext()), false),
@@ -126,3 +164,67 @@ std::pair<Function *, Function *> llvm::createSanitizerCtorAndInitFunctions(
   }
   return std::make_pair(Ctor, InitFunction);
 }
+
+void llvm::filterDeadComdatFunctions(
+    Module &M, SmallVectorImpl<Function *> &DeadComdatFunctions) {
+  // Build a map from the comdat to the number of entries in that comdat we
+  // think are dead. If this fully covers the comdat group, then the entire
+  // group is dead. If we find another entry in the comdat group though, we'll
+  // have to preserve the whole group.
+  SmallDenseMap<Comdat *, int, 16> ComdatEntriesCovered;
+  for (Function *F : DeadComdatFunctions) {
+    Comdat *C = F->getComdat();
+    assert(C && "Expected all input GVs to be in a comdat!");
+    ComdatEntriesCovered[C] += 1;
+  }
+
+  auto CheckComdat = [&](Comdat &C) {
+    auto CI = ComdatEntriesCovered.find(&C);
+    if (CI == ComdatEntriesCovered.end())
+      return;
+
+    // If this could have been covered by a dead entry, just subtract one to
+    // account for it.
+    if (CI->second > 0) {
+      CI->second -= 1;
+      return;
+    }
+
+    // If we've already accounted for all the entries that were dead, the
+    // entire comdat is alive so remove it from the map.
+    ComdatEntriesCovered.erase(CI);
+  };
+
+  auto CheckAllComdats = [&] {
+    for (Function &F : M.functions())
+      if (Comdat *C = F.getComdat()) {
+        CheckComdat(*C);
+        if (ComdatEntriesCovered.empty())
+          return;
+      }
+    for (GlobalVariable &GV : M.globals())
+      if (Comdat *C = GV.getComdat()) {
+        CheckComdat(*C);
+        if (ComdatEntriesCovered.empty())
+          return;
+      }
+    for (GlobalAlias &GA : M.aliases())
+      if (Comdat *C = GA.getComdat()) {
+        CheckComdat(*C);
+        if (ComdatEntriesCovered.empty())
+          return;
+      }
+  };
+  CheckAllComdats();
+
+  if (ComdatEntriesCovered.empty()) {
+    DeadComdatFunctions.clear();
+    return;
+  }
+
+  // Remove the entries that were not covering.
+  erase_if(DeadComdatFunctions, [&](GlobalValue *GV) {
+    return ComdatEntriesCovered.find(GV->getComdat()) ==
+           ComdatEntriesCovered.end();
+  });
+}