Implement support for the case when a reference to a addr-of-bb

label is generated, but then the block is deleted.  Since the
value is undefined, we just emit the label right after the entry 
label of the function.  It might matter that the label is in the
same section as the function was afterall.

llvm-svn: 98579

1 files changed, 10 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 63b05365d1c..fe78b23debd 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -307,6 +307,16 @@ void AsmPrinter::EmitFunctionHeader() {
   // do their wild and crazy things as required.
   EmitFunctionEntryLabel();
   
+  // If the function had address-taken blocks that got deleted, then we have
+  // references to the dangling symbols.  Emit them at the start of the function
+  // so that we don't get references to undefined symbols.
+  std::vector<MCSymbol*> DeadBlockSyms;
+  MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
+  for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
+    OutStreamer.AddComment("Address taken block that was later removed");
+    OutStreamer.EmitLabel(DeadBlockSyms[i]);
+  }
+  
   // Add some workaround for linkonce linkage on Cygwin\MinGW.
   if (MAI->getLinkOnceDirective() != 0 &&
       (F->hasLinkOnceLinkage() || F->hasWeakLinkage()))