1 files changed, 54 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 9f1e06b4725..3df1e4ea13e 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -573,6 +573,60 @@ const MCSection *TargetLoweringObjectFileMachO::getExplicitSectionGlobal(
   return S;
 }
 
+bool TargetLoweringObjectFileMachO::isSectionAtomizableBySymbols(
+    const MCSection &Section) const {
+    const MCSectionMachO &SMO = static_cast<const MCSectionMachO&>(Section);
+
+    // Sections holding 1 byte strings are atomized based on the data
+    // they contain.
+    // Sections holding 2 byte strings require symbols in order to be
+    // atomized.
+    // There is no dedicated section for 4 byte strings.
+    if (SMO.getKind().isMergeable1ByteCString())
+      return false;
+
+    if (SMO.getSegmentName() == "__TEXT" &&
+        SMO.getSectionName() == "__objc_classname" &&
+        SMO.getType() == MachO::S_CSTRING_LITERALS)
+      return false;
+
+    if (SMO.getSegmentName() == "__TEXT" &&
+        SMO.getSectionName() == "__objc_methname" &&
+        SMO.getType() == MachO::S_CSTRING_LITERALS)
+      return false;
+
+    if (SMO.getSegmentName() == "__TEXT" &&
+        SMO.getSectionName() == "__objc_methtype" &&
+        SMO.getType() == MachO::S_CSTRING_LITERALS)
+      return false;
+
+    if (SMO.getSegmentName() == "__DATA" &&
+        SMO.getSectionName() == "__cfstring")
+      return false;
+
+    // no_dead_strip sections are not atomized in practice.
+    if (SMO.hasAttribute(MachO::S_ATTR_NO_DEAD_STRIP))
+      return false;
+
+    switch (SMO.getType()) {
+    default:
+      return true;
+
+      // These sections are atomized at the element boundaries without using
+      // symbols.
+    case MachO::S_4BYTE_LITERALS:
+    case MachO::S_8BYTE_LITERALS:
+    case MachO::S_16BYTE_LITERALS:
+    case MachO::S_LITERAL_POINTERS:
+    case MachO::S_NON_LAZY_SYMBOL_POINTERS:
+    case MachO::S_LAZY_SYMBOL_POINTERS:
+    case MachO::S_MOD_INIT_FUNC_POINTERS:
+    case MachO::S_MOD_TERM_FUNC_POINTERS:
+    case MachO::S_INTERPOSING:
+      return false;
+    }
+}
+
 const MCSection *TargetLoweringObjectFileMachO::
 SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
                        Mangler &Mang, const TargetMachine &TM) const {