Add support for implicit TLS model used with MS VC runtime.
Patch by Kai Nacke!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150307 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 1343b57..6d29206 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -7355,6 +7355,68 @@
unsigned Reg = Subtarget->is64Bit() ? X86::RAX : X86::EAX;
return DAG.getCopyFromReg(Chain, DL, Reg, getPointerTy(),
Chain.getValue(1));
+ } else if (Subtarget->isTargetWindows()) {
+ // Just use the implicit TLS architecture
+ // Need to generate someting similar to:
+ // mov rdx, qword [gs:abs 58H]; Load pointer to ThreadLocalStorage
+ // ; from TEB
+ // mov ecx, dword [rel _tls_index]: Load index (from C runtime)
+ // mov rcx, qword [rdx+rcx*8]
+ // mov eax, .tls$:tlsvar
+ // [rax+rcx] contains the address
+ // Windows 64bit: gs:0x58
+ // Windows 32bit: fs:__tls_array
+
+ // If GV is an alias then use the aliasee for determining
+ // thread-localness.
+ if (const GlobalAlias *GA = dyn_cast<GlobalAlias>(GV))
+ GV = GA->resolveAliasedGlobal(false);
+ DebugLoc dl = GA->getDebugLoc();
+ SDValue Chain = DAG.getEntryNode();
+
+ // Get the Thread Pointer, which is %fs:__tls_array (32-bit) or
+ // %gs:0x58 (64-bit).
+ Value *Ptr = Constant::getNullValue(Subtarget->is64Bit()
+ ? Type::getInt8PtrTy(*DAG.getContext(),
+ 256)
+ : Type::getInt32PtrTy(*DAG.getContext(),
+ 257));
+
+ SDValue ThreadPointer = DAG.getLoad(getPointerTy(), dl, Chain,
+ Subtarget->is64Bit()
+ ? DAG.getIntPtrConstant(0x58)
+ : DAG.getExternalSymbol("_tls_array",
+ getPointerTy()),
+ MachinePointerInfo(Ptr),
+ false, false, false, 0);
+
+ // Load the _tls_index variable
+ SDValue IDX = DAG.getExternalSymbol("_tls_index", getPointerTy());
+ if (Subtarget->is64Bit())
+ IDX = DAG.getExtLoad(ISD::ZEXTLOAD, dl, getPointerTy(), Chain,
+ IDX, MachinePointerInfo(), MVT::i32,
+ false, false, 0);
+ else
+ IDX = DAG.getLoad(getPointerTy(), dl, Chain, IDX, MachinePointerInfo(),
+ false, false, false, 0);
+
+ SDValue Scale = DAG.getConstant(Log2_64_Ceil(TD->getPointerSize()),
+ getPointerTy());
+ IDX = DAG.getNode(ISD::SHL, dl, getPointerTy(), IDX, Scale);
+
+ SDValue res = DAG.getNode(ISD::ADD, dl, getPointerTy(), ThreadPointer, IDX);
+ res = DAG.getLoad(getPointerTy(), dl, Chain, res, MachinePointerInfo(),
+ false, false, false, 0);
+
+ // Get the offset of start of .tls section
+ SDValue TGA = DAG.getTargetGlobalAddress(GA->getGlobal(), dl,
+ GA->getValueType(0),
+ GA->getOffset(), X86II::MO_SECREL);
+ SDValue Offset = DAG.getNode(X86ISD::Wrapper, dl, getPointerTy(), TGA);
+
+ // The address of the thread local variable is the add of the thread
+ // pointer with the offset of the variable.
+ return DAG.getNode(ISD::ADD, dl, getPointerTy(), res, Offset);
}
llvm_unreachable("TLS not implemented for this target.");