Modify emission of jump tables on darwin to emit an extra "l" label that
delimits the boundaries of jump tables.  This lets the linker's dead code
stripping optimization do a better job.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33315 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCTargetAsmInfo.cpp b/lib/Target/PowerPC/PPCTargetAsmInfo.cpp
index b9f5849..b54c9e9 100644
--- a/lib/Target/PowerPC/PPCTargetAsmInfo.cpp
+++ b/lib/Target/PowerPC/PPCTargetAsmInfo.cpp
@@ -57,6 +57,13 @@
   UsedDirective = "\t.no_dead_strip\t";
   WeakRefDirective = "\t.weak_reference\t";
   HiddenDirective = "\t.private_extern\t";
+  
+  // In non-PIC modes, emit a special label before jump tables so that the
+  // linker can perform more accurate dead code stripping.
+  if (TM.getRelocationModel() != Reloc::PIC_) {
+    // Emit a local label that is preserved until the linker runs.
+    JumpTableSpecialLabelPrefix = "l";
+  }
 }
 
 LinuxTargetAsmInfo::LinuxTargetAsmInfo(const PPCTargetMachine &TM)