[ARM] Allow using emulated tls on platforms other than ELF

[mstorsjo]

Summary

This matches how it is done on X86.

This allows using emulated tls on windows; in MinGW environments, native tls isn't supported at the moment.

[compnerd]

Please add a test case with emulated TLS on Darwin as -femulated-tls will now lower with emulated TLS on Darwin too.

llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp

ARMTargetLowering::LowerToTLSExecModels(GlobalAddressSDNode *GA,
 
   // 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, PtrVT, ThreadPointer, Offset);
 }
 
 SDValue
 ARMTargetLowering::LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const {
+  GlobalAddressSDNode *GA = cast<GlobalAddressSDNode>(Op);
+  if (DAG.getTarget().Options.EmulatedTLS)
+    return LowerToTLSEmulatedModel(GA, DAG);
+
   if (Subtarget->isTargetDarwin())
     return LowerGlobalTLSAddressDarwin(Op, DAG);
 
   if (Subtarget->isTargetWindows())
     return LowerGlobalTLSAddressWindows(Op, DAG);
 
   // TODO: implement the "local dynamic" model
   assert(Subtarget->isTargetELF() && "Only ELF implemented here");
-  GlobalAddressSDNode *GA = cast<GlobalAddressSDNode>(Op);
-  if (DAG.getTarget().Options.EmulatedTLS)
-    return LowerToTLSEmulatedModel(GA, DAG);
-
   TLSModel::Model model = getTargetMachine().getTLSModel(GA->getGlobal());
 
   switch (model) {
     case TLSModel::GeneralDynamic:
     case TLSModel::LocalDynamic:
       return LowerToTLSGeneralDynamicModel(GA, DAG);
     case TLSModel::InitialExec:
     case TLSModel::LocalExec:

llvm/trunk/test/CodeGen/ARM/emutls_generic.ll

 ; RUN: llc < %s -emulated-tls -mtriple=arm-linux-android -relocation-model=pic \
 ; RUN:     | FileCheck -check-prefix=ARM_32 %s
 ; RUN: llc < %s -emulated-tls -mtriple=arm-linux-androidabi -relocation-model=pic \
 ; RUN:     | FileCheck -check-prefix=ARM_32 %s
 ; RUN: llc < %s -emulated-tls -mtriple=arm-linux-androidabi -relocation-model=pic -O3 \
 ; RUN:     | FileCheck -check-prefix=ARM_32 %s
 ; RUN: llc < %s -emulated-tls -mtriple=arm-linux-androidabi -O3 \
 ; RUN:     | FileCheck -check-prefix=ARM_32 %s
+; RUN: llc < %s -emulated-tls -mtriple=arm-apple-darwin -O3 \
+; RUN:     | FileCheck -check-prefix=DARWIN %s
+; RUN: llc < %s -emulated-tls -mtriple=thumbv7-windows-gnu -O3 \
+; RUN:     | FileCheck -check-prefix=WIN %s
 
 ; Make sure that TLS symbols are emitted in expected order.
 
 @external_x = external thread_local global i32, align 8
 @external_y = thread_local global i8 7, align 2
 @internal_y = internal thread_local global i64 9, align 16
 
 define i32* @get_external_x() {

 ; ARM_32-LABEL:  __emutls_v.internal_y:
 ; ARM_32-NEXT:   .long 8
 ; ARM_32-NEXT:   .long 16
 ; ARM_32-NEXT:   .long 0
 ; ARM_32-NEXT:   .long __emutls_t.internal_y
 ; ARM_32-LABEL:  __emutls_t.internal_y:
 ; ARM_32-NEXT:   .long 9
 ; ARM_32-NEXT:   .long 0
+
+; WIN-LABEL:  get_external_x:
+; WIN:        movw r0, :lower16:__emutls_v.external_x
+; WIN:        movt r0, :upper16:__emutls_v.external_x
+; WIN:        bl __emutls_get_address
+; WIN-LABEL:  get_external_y:
+; WIN:        movw r0, :lower16:__emutls_v.external_y
+; WIN:        movt r0, :upper16:__emutls_v.external_y
+; WIN:        bl __emutls_get_address
+; WIN-LABEL:  get_internal_y:
+; WIN:        movw r0, :lower16:__emutls_v.internal_y
+; WIN:        movt r0, :upper16:__emutls_v.internal_y
+; WIN:        bl __emutls_get_address
+; WIN-NOT:    __emutls_t.external_x
+; WIN-NOT:    __emutls_v.external_x:
+; WIN:        .data{{$}}
+; WIN:        .globl __emutls_v.external_y
+; WIN:        .p2align 2
+; WIN-LABEL:  __emutls_v.external_y:
+; WIN-NEXT:   .long 1
+; WIN-NEXT:   .long 2
+; WIN-NEXT:   .long 0
+; WIN-NEXT:   .long __emutls_t.external_y
+; WIN:        .section .rdata,
+; WIN-LABEL:  __emutls_t.external_y:
+; WIN-NEXT:   .byte 7
+; WIN:        .data{{$}}
+; WIN-NOT:    .globl
+; WIN:        .p2align 2
+; WIN-LABEL:  __emutls_v.internal_y:
+; WIN-NEXT:   .long 8
+; WIN-NEXT:   .long 16
+; WIN-NEXT:   .long 0
+; WIN-NEXT:   .long __emutls_t.internal_y
+; WIN-LABEL:  __emutls_t.internal_y:
+; .quad 9 is equivalent to .long 9 .long 0
+; WIN-NEXT:   .quad 9
+
+; DARWIN-LABEL:  _get_external_x:
+; DARWIN:        bl ___emutls_get_address
+; DARWIN:        .long L___emutls_v.external_x$non_lazy_ptr-(LPC0_0+8)
+; DARWIN-LABEL:  _get_external_y:
+; DARWIN:        bl ___emutls_get_address
+; DARWIN:        .long ___emutls_v.external_y-(LPC1_0+8)
+; DARWIN-LABEL:  _get_internal_y:
+; DARWIN:        bl ___emutls_get_address
+; DARWIN:        .long ___emutls_v.internal_y-(LPC2_0+8)
+; DARWIN-NOT:    ___emutls_t.external_x
+; DARWIN-NOT:    ___emutls_v.external_x:
+; DARWIN:        .section __DATA,__data
+; DARWIN:        .globl ___emutls_v.external_y
+; DARWIN:        .p2align 2
+; DARWIN-LABEL:  ___emutls_v.external_y:
+; DARWIN-NEXT:   .long 1
+; DARWIN-NEXT:   .long 2
+; DARWIN-NEXT:   .long 0
+; DARWIN-NEXT:   .long ___emutls_t.external_y
+; DARWIN:        .section __TEXT,__const
+; DARWIN-LABEL:  ___emutls_t.external_y:
+; DARWIN-NEXT:   .byte 7
+; DARWIN:        .section __DATA,__data
+; DARWIN-NOT:    .globl
+; DARWIN:        .p2align 2
+; DARWIN-LABEL:  ___emutls_v.internal_y:
+; DARWIN-NEXT:   .long 8
+; DARWIN-NEXT:   .long 16
+; DARWIN-NEXT:   .long 0
+; DARWIN-NEXT:   .long ___emutls_t.internal_y
+; DARWIN-LABEL:  ___emutls_t.internal_y:
+; DARWIN-NEXT:   .long 9
+; DARWIN-NEXT:   .long 0