[TLS] use emulated TLS if the target supports only this mode

Emulated TLS is enabled by llc flag -emulated-tls,
which is passed by clang driver.
When llc is called explicitly or from other drivers like LTO,
missing -emulated-tls flag would generate wrong TLS code for targets
that supports only this mode.
Now use useEmulatedTLS() instead of Options.EmulatedTLS to decide whether
emulated TLS code should be generated.
Unit tests are modified to run with and without the -emulated-tls flag.

Differential Revision: https://reviews.llvm.org/D42999

llvm-svn: 326341

8 files changed, 15 insertions, 7 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index 8829d1a6d96..eb21585508f 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -3979,7 +3979,7 @@ AArch64TargetLowering::LowerELFGlobalTLSAddress(SDValue Op,
 SDValue AArch64TargetLowering::LowerGlobalTLSAddress(SDValue Op,
                                                      SelectionDAG &DAG) const {
   const GlobalAddressSDNode *GA = cast<GlobalAddressSDNode>(Op);
-  if (DAG.getTarget().Options.EmulatedTLS)
+  if (DAG.getTarget().useEmulatedTLS())
     return LowerToTLSEmulatedModel(GA, DAG);
 
   if (Subtarget->isTargetDarwin())
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index ede008dbae1..4cdc064838f 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -3005,7 +3005,7 @@ ARMTargetLowering::LowerToTLSExecModels(GlobalAddressSDNode *GA,
 SDValue
 ARMTargetLowering::LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const {
   GlobalAddressSDNode *GA = cast<GlobalAddressSDNode>(Op);
-  if (DAG.getTarget().Options.EmulatedTLS)
+  if (DAG.getTarget().useEmulatedTLS())
     return LowerToTLSEmulatedModel(GA, DAG);
 
   if (Subtarget->isTargetDarwin())
diff --git a/llvm/lib/Target/Mips/MipsISelLowering.cpp b/llvm/lib/Target/Mips/MipsISelLowering.cpp
index 99abbff4593..7e6ce442625 100644
--- a/llvm/lib/Target/Mips/MipsISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsISelLowering.cpp
@@ -2069,7 +2069,7 @@ lowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const
   // Local Exec TLS Model.
 
   GlobalAddressSDNode *GA = cast<GlobalAddressSDNode>(Op);
-  if (DAG.getTarget().Options.EmulatedTLS)
+  if (DAG.getTarget().useEmulatedTLS())
     return LowerToTLSEmulatedModel(GA, DAG);
 
   SDLoc DL(GA);
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 38e77bb0192..096285c48e4 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -2571,7 +2571,7 @@ SDValue PPCTargetLowering::LowerGlobalTLSAddress(SDValue Op,
   // large models could be added if users need it, at the cost of
   // additional complexity.
   GlobalAddressSDNode *GA = cast<GlobalAddressSDNode>(Op);
-  if (DAG.getTarget().Options.EmulatedTLS)
+  if (DAG.getTarget().useEmulatedTLS())
     return LowerToTLSEmulatedModel(GA, DAG);
 
   SDLoc dl(GA);
diff --git a/llvm/lib/Target/Sparc/SparcISelLowering.cpp b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
index d9548ff90d7..f120c021472 100644
--- a/llvm/lib/Target/Sparc/SparcISelLowering.cpp
+++ b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
@@ -2036,7 +2036,7 @@ SDValue SparcTargetLowering::LowerGlobalTLSAddress(SDValue Op,
                                                    SelectionDAG &DAG) const {
 
   GlobalAddressSDNode *GA = cast<GlobalAddressSDNode>(Op);
-  if (DAG.getTarget().Options.EmulatedTLS)
+  if (DAG.getTarget().useEmulatedTLS())
     return LowerToTLSEmulatedModel(GA, DAG);
 
   SDLoc DL(GA);
diff --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
index be7fac1d777..7aeced28445 100644
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -2663,7 +2663,7 @@ SDValue SystemZTargetLowering::lowerThreadPointer(const SDLoc &DL,
 
 SDValue SystemZTargetLowering::lowerGlobalTLSAddress(GlobalAddressSDNode *Node,
                                                      SelectionDAG &DAG) const {
-  if (DAG.getTarget().Options.EmulatedTLS)
+  if (DAG.getTarget().useEmulatedTLS())
     return LowerToTLSEmulatedModel(Node, DAG);
   SDLoc DL(Node);
   const GlobalValue *GV = Node->getGlobal();
diff --git a/llvm/lib/Target/TargetMachine.cpp b/llvm/lib/Target/TargetMachine.cpp
index 826766890dd..2a0968565f2 100644
--- a/llvm/lib/Target/TargetMachine.cpp
+++ b/llvm/lib/Target/TargetMachine.cpp
@@ -192,6 +192,14 @@ bool TargetMachine::shouldAssumeDSOLocal(const Module &M,
   return false;
 }
 
+bool TargetMachine::useEmulatedTLS() const {
+  // Returns Options.EmulatedTLS if the -emulated-tls or -no-emulated-tls
+  // was specified explicitly; otherwise uses target triple to decide default.
+  if (Options.ExplicitEmulatedTLS)
+    return Options.EmulatedTLS;
+  return getTargetTriple().hasDefaultEmulatedTLS();
+}
+
 TLSModel::Model TargetMachine::getTLSModel(const GlobalValue *GV) const {
   bool IsPIE = GV->getParent()->getPIELevel() != PIELevel::Default;
   Reloc::Model RM = getRelocationModel();
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 3a89c195907..e4f86127a06 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -15638,7 +15638,7 @@ X86TargetLowering::LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const {
 
   GlobalAddressSDNode *GA = cast<GlobalAddressSDNode>(Op);
 
-  if (DAG.getTarget().Options.EmulatedTLS)
+  if (DAG.getTarget().useEmulatedTLS())
     return LowerToTLSEmulatedModel(GA, DAG);
 
   const GlobalValue *GV = GA->getGlobal();