Extend the IL for selecting TLS models (PR9788)

This allows the user/front-end to specify a model that is better
than what LLVM would choose by default. For example, a variable
might be declared as

  @x = thread_local(initialexec) global i32 42

if it will not be used in a shared library that is dlopen'ed.

If the specified model isn't supported by the target, or if LLVM can
make a better choice, a different model may be used.

llvm-svn: 159077

1 files changed, 21 insertions, 1 deletions

diff --git a/llvm/lib/VMCore/AsmWriter.cpp b/llvm/lib/VMCore/AsmWriter.cpp
index 4a7fde19055..9147b635126 100644
--- a/llvm/lib/VMCore/AsmWriter.cpp
+++ b/llvm/lib/VMCore/AsmWriter.cpp
@@ -1376,6 +1376,26 @@ static void PrintVisibility(GlobalValue::VisibilityTypes Vis,
   }
 }
 
+static void PrintThreadLocalModel(GlobalVariable::ThreadLocalMode TLM,
+                                  formatted_raw_ostream &Out) {
+  switch (TLM) {
+    case GlobalVariable::NotThreadLocal:
+      break;
+    case GlobalVariable::GeneralDynamicTLSModel:
+      Out << "thread_local ";
+      break;
+    case GlobalVariable::LocalDynamicTLSModel:
+      Out << "thread_local(localdynamic) ";
+      break;
+    case GlobalVariable::InitialExecTLSModel:
+      Out << "thread_local(initialexec) ";
+      break;
+    case GlobalVariable::LocalExecTLSModel:
+      Out << "thread_local(localexec) ";
+      break;
+  }
+}
+
 void AssemblyWriter::printGlobal(const GlobalVariable *GV) {
   if (GV->isMaterializable())
     Out << "; Materializable\n";
@@ -1388,8 +1408,8 @@ void AssemblyWriter::printGlobal(const GlobalVariable *GV) {
 
   PrintLinkage(GV->getLinkage(), Out);
   PrintVisibility(GV->getVisibility(), Out);
+  PrintThreadLocalModel(GV->getThreadLocalMode(), Out);
 
-  if (GV->isThreadLocal()) Out << "thread_local ";
   if (unsigned AddressSpace = GV->getType()->getAddressSpace())
     Out << "addrspace(" << AddressSpace << ") ";
   if (GV->hasUnnamedAddr()) Out << "unnamed_addr ";