Add support for targets that want to do something with the llvm.used list,

because they have an aggressive linker that does dead code stripping.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30604 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 21 insertions, 2 deletions

diff --git a/lib/CodeGen/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter.cpp
index bcdb393c23..bfc0519806 100644
--- a/lib/CodeGen/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter.cpp
@@ -253,8 +253,11 @@ bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
 
   assert(GV->hasInitializer() && "Not a special LLVM global!");
   
-  if (GV->getName() == "llvm.used")
-    return true;  // No need to emit this at all.
+  if (GV->getName() == "llvm.used") {
+    if (TAI->getUsedDirective() != 0)    // No need to emit this at all.
+      EmitLLVMUsedList(GV->getInitializer());
+    return true;
+  }
 
   if (GV->getName() == "llvm.global_ctors" && GV->use_empty()) {
     SwitchToDataSection(TAI->getStaticCtorsSection(), 0);
@@ -273,6 +276,22 @@ bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
   return false;
 }
 
+/// EmitLLVMUsedList - For targets that define a TAI::UsedDirective, mark each
+/// global in the specified llvm.used list as being used with this directive.
+void AsmPrinter::EmitLLVMUsedList(Constant *List) {
+  const char *Directive = TAI->getUsedDirective();
+
+  // Should be an array of 'sbyte*'.
+  ConstantArray *InitList = dyn_cast<ConstantArray>(List);
+  if (InitList == 0) return;
+  
+  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
+    O << Directive;
+    EmitConstantValueOnly(InitList->getOperand(i));
+    O << "\n";
+  }
+}
+
 /// EmitXXStructorList - Emit the ctor or dtor list.  This just prints out the 
 /// function pointers, ignoring the init priority.
 void AsmPrinter::EmitXXStructorList(Constant *List) {