Implement the local-dynamic TLS model for x86 (PR3985)
This implements codegen support for accesses to thread-local variables
using the local-dynamic model, and adds a clean-up pass so that the base
address for the TLS block can be re-used between local-dynamic access on
an execution path.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157818 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index f3b66e4..8d0e843 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -7263,7 +7263,7 @@
static SDValue
GetTLSADDR(SelectionDAG &DAG, SDValue Chain, GlobalAddressSDNode *GA,
SDValue *InFlag, const EVT PtrVT, unsigned ReturnReg,
- unsigned char OperandFlags) {
+ unsigned char OperandFlags, bool LocalDynamic = false) {
MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo();
SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
DebugLoc dl = GA->getDebugLoc();
@@ -7271,12 +7271,16 @@
GA->getValueType(0),
GA->getOffset(),
OperandFlags);
+
+ X86ISD::NodeType CallType = LocalDynamic ? X86ISD::TLSBASEADDR
+ : X86ISD::TLSADDR;
+
if (InFlag) {
SDValue Ops[] = { Chain, TGA, *InFlag };
- Chain = DAG.getNode(X86ISD::TLSADDR, dl, NodeTys, Ops, 3);
+ Chain = DAG.getNode(CallType, dl, NodeTys, Ops, 3);
} else {
SDValue Ops[] = { Chain, TGA };
- Chain = DAG.getNode(X86ISD::TLSADDR, dl, NodeTys, Ops, 2);
+ Chain = DAG.getNode(CallType, dl, NodeTys, Ops, 2);
}
// TLSADDR will be codegen'ed as call. Inform MFI that function has calls.
@@ -7308,6 +7312,45 @@
X86::RAX, X86II::MO_TLSGD);
}
+static SDValue LowerToTLSLocalDynamicModel(GlobalAddressSDNode *GA,
+ SelectionDAG &DAG,
+ const EVT PtrVT,
+ bool is64Bit) {
+ DebugLoc dl = GA->getDebugLoc();
+
+ // Get the start address of the TLS block for this module.
+ X86MachineFunctionInfo* MFI = DAG.getMachineFunction()
+ .getInfo<X86MachineFunctionInfo>();
+ MFI->incNumLocalDynamicTLSAccesses();
+
+ SDValue Base;
+ if (is64Bit) {
+ Base = GetTLSADDR(DAG, DAG.getEntryNode(), GA, NULL, PtrVT, X86::RAX,
+ X86II::MO_TLSLD, /*LocalDynamic=*/true);
+ } else {
+ SDValue InFlag;
+ SDValue Chain = DAG.getCopyToReg(DAG.getEntryNode(), dl, X86::EBX,
+ DAG.getNode(X86ISD::GlobalBaseReg, DebugLoc(), PtrVT), InFlag);
+ InFlag = Chain.getValue(1);
+ Base = GetTLSADDR(DAG, Chain, GA, &InFlag, PtrVT, X86::EAX,
+ X86II::MO_TLSLDM, /*LocalDynamic=*/true);
+ }
+
+ // Note: the CleanupLocalDynamicTLSPass will remove redundant computations
+ // of Base.
+
+ // Build x@dtpoff.
+ unsigned char OperandFlags = X86II::MO_DTPOFF;
+ unsigned WrapperKind = X86ISD::Wrapper;
+ SDValue TGA = DAG.getTargetGlobalAddress(GA->getGlobal(), dl,
+ GA->getValueType(0),
+ GA->getOffset(), OperandFlags);
+ SDValue Offset = DAG.getNode(WrapperKind, dl, PtrVT, TGA);
+
+ // Add x@dtpoff with the base.
+ return DAG.getNode(ISD::ADD, dl, PtrVT, Offset, Base);
+}
+
// Lower ISD::GlobalTLSAddress using the "initial exec" or "local exec" model.
static SDValue LowerToTLSExecModel(GlobalAddressSDNode *GA, SelectionDAG &DAG,
const EVT PtrVT, TLSModel::Model model,
@@ -7372,8 +7415,6 @@
const GlobalValue *GV = GA->getGlobal();
if (Subtarget->isTargetELF()) {
- // TODO: implement the "local dynamic" model
-
// If GV is an alias then use the aliasee for determining
// thread-localness.
if (const GlobalAlias *GA = dyn_cast<GlobalAlias>(GV))
@@ -7383,11 +7424,12 @@
switch (model) {
case TLSModel::GeneralDynamic:
- case TLSModel::LocalDynamic: // not implemented
if (Subtarget->is64Bit())
return LowerToTLSGeneralDynamicModel64(GA, DAG, getPointerTy());
return LowerToTLSGeneralDynamicModel32(GA, DAG, getPointerTy());
-
+ case TLSModel::LocalDynamic:
+ return LowerToTLSLocalDynamicModel(GA, DAG, getPointerTy(),
+ Subtarget->is64Bit());
case TLSModel::InitialExec:
case TLSModel::LocalExec:
return LowerToTLSExecModel(GA, DAG, getPointerTy(), model,
@@ -11257,6 +11299,7 @@
case X86ISD::FRSQRT: return "X86ISD::FRSQRT";
case X86ISD::FRCP: return "X86ISD::FRCP";
case X86ISD::TLSADDR: return "X86ISD::TLSADDR";
+ case X86ISD::TLSBASEADDR: return "X86ISD::TLSBASEADDR";
case X86ISD::TLSCALL: return "X86ISD::TLSCALL";
case X86ISD::EH_RETURN: return "X86ISD::EH_RETURN";
case X86ISD::TC_RETURN: return "X86ISD::TC_RETURN";