1 files changed, 51 insertions, 5 deletions
diff --git a/lib/Target/X86/X86AsmBackend.cpp b/lib/Target/X86/X86AsmBackend.cpp
index e6654ef..a44afc6 100644
--- a/lib/Target/X86/X86AsmBackend.cpp
+++ b/lib/Target/X86/X86AsmBackend.cpp
@@ -9,6 +9,7 @@
 
 #include "llvm/Target/TargetAsmBackend.h"
 #include "X86.h"
+#include "llvm/MC/MCSectionMachO.h"
 #include "llvm/Target/TargetRegistry.h"
 #include "llvm/Target/TargetAsmBackend.h"
 using namespace llvm;
@@ -17,18 +18,63 @@ namespace {
 
 class X86AsmBackend : public TargetAsmBackend {
 public:
-  X86AsmBackend(const Target &T, MCAssembler &A)
+  X86AsmBackend(const Target &T)
     : TargetAsmBackend(T) {}
 };
 
+class DarwinX86AsmBackend : public X86AsmBackend {
+public:
+  DarwinX86AsmBackend(const Target &T)
+    : X86AsmBackend(T) {}
+
+  virtual bool hasAbsolutizedSet() const { return true; }
+
+  virtual bool hasScatteredSymbols() const { return true; }
+};
+
+class DarwinX86_32AsmBackend : public DarwinX86AsmBackend {
+public:
+  DarwinX86_32AsmBackend(const Target &T)
+    : DarwinX86AsmBackend(T) {}
+};
+
+class DarwinX86_64AsmBackend : public DarwinX86AsmBackend {
+public:
+  DarwinX86_64AsmBackend(const Target &T)
+    : DarwinX86AsmBackend(T) {}
+
+  virtual bool doesSectionRequireSymbols(const MCSection &Section) const {
+    // Temporary labels in the string literals sections require symbols. The
+    // issue is that the x86_64 relocation format does not allow symbol +
+    // offset, and so the linker does not have enough information to resolve the
+    // access to the appropriate atom unless an external relocation is used. For
+    // non-cstring sections, we expect the compiler to use a non-temporary label
+    // for anything that could have an addend pointing outside the symbol.
+    //
+    // See <rdar://problem/4765733>.
+    const MCSectionMachO &SMO = static_cast<const MCSectionMachO&>(Section);
+    return SMO.getType() == MCSectionMachO::S_CSTRING_LITERALS;
+  }
+};
+
 }
 
 TargetAsmBackend *llvm::createX86_32AsmBackend(const Target &T,
-                                               MCAssembler &A) {
-  return new X86AsmBackend(T, A);
+                                               const std::string &TT) {
+  switch (Triple(TT).getOS()) {
+  case Triple::Darwin:
+    return new DarwinX86_32AsmBackend(T);
+  default:
+    return new X86AsmBackend(T);
+  }
 }
 
 TargetAsmBackend *llvm::createX86_64AsmBackend(const Target &T,
-                                               MCAssembler &A) {
-  return new X86AsmBackend(T, A);
+                                               const std::string &TT) {
+  switch (Triple(TT).getOS()) {
+  case Triple::Darwin:
+    return new DarwinX86_64AsmBackend(T);
+  default:
+    return new X86AsmBackend(T);
+  }
 }