Implement initial-exec TLS model for 32-bit PIC x86
This fixes a TODO from 2007 :) Previously, LLVM would emit the wrong
code here (see the update to test/CodeGen/X86/tls-pie.ll).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156611 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 688c25c..75e0588 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -7286,11 +7286,10 @@
X86::RAX, X86II::MO_TLSGD);
}
-// Lower ISD::GlobalTLSAddress using the "initial exec" (for no-pic) or
-// "local exec" model.
+// Lower ISD::GlobalTLSAddress using the "initial exec" or "local exec" model.
static SDValue LowerToTLSExecModel(GlobalAddressSDNode *GA, SelectionDAG &DAG,
const EVT PtrVT, TLSModel::Model model,
- bool is64Bit) {
+ bool is64Bit, bool isPIC) {
DebugLoc dl = GA->getDebugLoc();
// Get the Thread Pointer, which is %gs:0 (32-bit) or %fs:0 (64-bit).
@@ -7308,25 +7307,36 @@
unsigned WrapperKind = X86ISD::Wrapper;
if (model == TLSModel::LocalExec) {
OperandFlags = is64Bit ? X86II::MO_TPOFF : X86II::MO_NTPOFF;
- } else if (is64Bit) {
- assert(model == TLSModel::InitialExec);
- OperandFlags = X86II::MO_GOTTPOFF;
- WrapperKind = X86ISD::WrapperRIP;
+ } else if (model == TLSModel::InitialExec) {
+ if (is64Bit) {
+ OperandFlags = X86II::MO_GOTTPOFF;
+ WrapperKind = X86ISD::WrapperRIP;
+ } else {
+ OperandFlags = isPIC ? X86II::MO_GOTNTPOFF : X86II::MO_INDNTPOFF;
+ }
} else {
- assert(model == TLSModel::InitialExec);
- OperandFlags = X86II::MO_INDNTPOFF;
+ llvm_unreachable("Unexpected model");
}
- // emit "addl x@ntpoff,%eax" (local exec) or "addl x@indntpoff,%eax" (initial
- // exec)
+ // emit "addl x@ntpoff,%eax" (local exec)
+ // or "addl x@indntpoff,%eax" (initial exec)
+ // or "addl x@gotntpoff(%ebx) ,%eax" (initial exec, 32-bit pic)
SDValue TGA = DAG.getTargetGlobalAddress(GA->getGlobal(), dl,
GA->getValueType(0),
GA->getOffset(), OperandFlags);
SDValue Offset = DAG.getNode(WrapperKind, dl, PtrVT, TGA);
- if (model == TLSModel::InitialExec)
- Offset = DAG.getLoad(PtrVT, dl, DAG.getEntryNode(), Offset,
- MachinePointerInfo::getGOT(), false, false, false, 0);
+ if (model == TLSModel::InitialExec) {
+ if (isPIC && !is64Bit) {
+ Offset = DAG.getNode(ISD::ADD, dl, PtrVT,
+ DAG.getNode(X86ISD::GlobalBaseReg, DebugLoc(), PtrVT),
+ Offset);
+ } else {
+ Offset = DAG.getLoad(PtrVT, dl, DAG.getEntryNode(), Offset,
+ MachinePointerInfo::getGOT(), false, false, false,
+ 0);
+ }
+ }
// The address of the thread local variable is the add of the thread
// pointer with the offset of the variable.
@@ -7341,7 +7351,6 @@
if (Subtarget->isTargetELF()) {
// TODO: implement the "local dynamic" model
- // TODO: implement the "initial exec"model for pic executables
// If GV is an alias then use the aliasee for determining
// thread-localness.
@@ -7360,7 +7369,8 @@
case TLSModel::InitialExec:
case TLSModel::LocalExec:
return LowerToTLSExecModel(GA, DAG, getPointerTy(), model,
- Subtarget->is64Bit());
+ Subtarget->is64Bit(),
+ getTargetMachine().getRelocationModel() == Reloc::PIC_);
}
llvm_unreachable("Unknown TLS model.");
}