ARM: support TLS for WoA

Add support for TLS access for Windows on ARM.  This generates a similar access
to MSVC for ARM.

The changes to the tablegen data is needed to support loading an external symbol
global that is not for a call.  The adjustments to the DAG to DAG transforms are
needed to preserve the 32-bit move.

llvm-svn: 259676
diff --git a/llvm/test/CodeGen/ARM/Windows/tls.ll b/llvm/test/CodeGen/ARM/Windows/tls.ll
new file mode 100644
index 0000000..9022f8a
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/Windows/tls.ll
@@ -0,0 +1,143 @@
+; RUN: llc -mtriple thumbv7--windows %s -o - | FileCheck %s
+
+@i = thread_local global i32 0
+@j = external thread_local global i32
+@k = internal thread_local global i32 0
+@l = hidden thread_local global i32 0
+@m = external hidden thread_local global i32
+@n = thread_local global i16 0
+@o = thread_local global i8 0
+
+define i32 @f() {
+  %1 = load i32, i32* @i
+  ret i32 %1
+}
+
+; CHECK:      mrc p15, #0, [[TEB:r[0-9]]], c13, c0, #2
+
+; CHECK:      movw [[TLS_INDEX:r[0-9]]], :lower16:_tls_index
+; CHECK-NEXT: movt [[TLS_INDEX]], :upper16:_tls_index
+; CHECK-NEXT: ldr [[INDEX:r[0-9]]], {{\[}}[[TLS_INDEX]]]
+
+; CHECK:      ldr [[TLS_POINTER:r[0-9]]], {{\[}}[[TEB]], #44]
+; CHECK-NEXT: ldr{{.w}} [[TLS:r[0-9]]], {{\[}}[[TLS_POINTER]], [[INDEX]], lsl #2]
+
+; CHECK-NEXT: movw [[SLOT:r[0-9]]], :lower16:i
+; CHECK-NEXT: movt [[SLOT]], :upper16:i
+
+; CHECK-NEXT: ldr r0, {{\[}}[[TLS]], [[SLOT]]]
+
+define i32 @e() {
+  %1 = load i32, i32* @j
+  ret i32 %1
+}
+
+; CHECK:      mrc p15, #0, [[TEB:r[0-9]]], c13, c0, #2
+
+; CHECK:      movw [[TLS_INDEX:r[0-9]]], :lower16:_tls_index
+; CHECK-NEXT: movt [[TLS_INDEX]], :upper16:_tls_index
+; CHECK-NEXT: ldr [[INDEX:r[0-9]]], {{\[}}[[TLS_INDEX]]]
+
+; CHECK:      ldr [[TLS_POINTER:r[0-9]]], {{\[}}[[TEB]], #44]
+; CHECK-NEXT: ldr{{.w}} [[TLS:r[0-9]]], {{\[}}[[TLS_POINTER]], [[INDEX]], lsl #2]
+
+; CHECK-NEXT: movw [[SLOT:r[0-9]]], :lower16:j
+; CHECK-NEXT: movt [[SLOT]], :upper16:j
+
+; CHECK-NEXT: ldr r0, {{\[}}[[TLS]], [[SLOT]]]
+
+define i32 @d() {
+  %1 = load i32, i32* @k
+  ret i32 %1
+}
+
+; CHECK:      mrc p15, #0, [[TEB:r[0-9]]], c13, c0, #2
+
+; CHECK:      movw [[TLS_INDEX:r[0-9]]], :lower16:_tls_index
+; CHECK-NEXT: movt [[TLS_INDEX]], :upper16:_tls_index
+; CHECK-NEXT: ldr [[INDEX:r[0-9]]], {{\[}}[[TLS_INDEX]]]
+
+; CHECK:      ldr [[TLS_POINTER:r[0-9]]], {{\[}}[[TEB]], #44]
+; CHECK-NEXT: ldr{{.w}} [[TLS:r[0-9]]], {{\[}}[[TLS_POINTER]], [[INDEX]], lsl #2]
+
+; CHECK-NEXT: movw [[SLOT:r[0-9]]], :lower16:k
+; CHECK-NEXT: movt [[SLOT]], :upper16:k
+
+; CHECK-NEXT: ldr r0, {{\[}}[[TLS]], [[SLOT]]]
+
+define i32 @c() {
+  %1 = load i32, i32* @l
+  ret i32 %1
+}
+
+; CHECK:      mrc p15, #0, [[TEB:r[0-9]]], c13, c0, #2
+
+; CHECK:      movw [[TLS_INDEX:r[0-9]]], :lower16:_tls_index
+; CHECK-NEXT: movt [[TLS_INDEX]], :upper16:_tls_index
+; CHECK-NEXT: ldr [[INDEX:r[0-9]]], {{\[}}[[TLS_INDEX]]]
+
+; CHECK:      ldr [[TLS_POINTER:r[0-9]]], {{\[}}[[TEB]], #44]
+; CHECK-NEXT: ldr{{.w}} [[TLS:r[0-9]]], {{\[}}[[TLS_POINTER]], [[INDEX]], lsl #2]
+
+; CHECK-NEXT: movw [[SLOT:r[0-9]]], :lower16:l
+; CHECK-NEXT: movt [[SLOT]], :upper16:l
+
+; CHECK-NEXT: ldr r0, {{\[}}[[TLS]], [[SLOT]]]
+
+define i32 @b() {
+  %1 = load i32, i32* @m
+  ret i32 %1
+}
+
+; CHECK:      mrc p15, #0, [[TEB:r[0-9]]], c13, c0, #2
+
+; CHECK:      movw [[TLS_INDEX:r[0-9]]], :lower16:_tls_index
+; CHECK-NEXT: movt [[TLS_INDEX]], :upper16:_tls_index
+; CHECK-NEXT: ldr [[INDEX:r[0-9]]], {{\[}}[[TLS_INDEX]]]
+
+; CHECK:      ldr [[TLS_POINTER:r[0-9]]], {{\[}}[[TEB]], #44]
+; CHECK-NEXT: ldr{{.w}} [[TLS:r[0-9]]], {{\[}}[[TLS_POINTER]], [[INDEX]], lsl #2]
+
+; CHECK-NEXT: movw [[SLOT:r[0-9]]], :lower16:m
+; CHECK-NEXT: movt [[SLOT]], :upper16:m
+
+; CHECK-NEXT: ldr r0, {{\[}}[[TLS]], [[SLOT]]]
+
+define i16 @a() {
+  %1 = load i16, i16* @n
+  ret i16 %1
+}
+
+; CHECK:      mrc p15, #0, [[TEB:r[0-9]]], c13, c0, #2
+
+; CHECK:      movw [[TLS_INDEX:r[0-9]]], :lower16:_tls_index
+; CHECK-NEXT: movt [[TLS_INDEX]], :upper16:_tls_index
+; CHECK-NEXT: ldr [[INDEX:r[0-9]]], {{\[}}[[TLS_INDEX]]]
+
+; CHECK:      ldr [[TLS_POINTER:r[0-9]]], {{\[}}[[TEB]], #44]
+; CHECK-NEXT: ldr{{.w}} [[TLS:r[0-9]]], {{\[}}[[TLS_POINTER]], [[INDEX]], lsl #2]
+
+; CHECK-NEXT: movw [[SLOT:r[0-9]]], :lower16:n
+; CHECK-NEXT: movt [[SLOT]], :upper16:n
+
+; CHECK-NEXT: ldrh r0, {{\[}}[[TLS]], [[SLOT]]]
+
+define i8 @Z() {
+  %1 = load i8, i8* @o
+  ret i8 %1
+}
+
+; CHECK:      mrc p15, #0, [[TEB:r[0-9]]], c13, c0, #2
+
+; CHECK:      movw [[TLS_INDEX:r[0-9]]], :lower16:_tls_index
+; CHECK-NEXT: movt [[TLS_INDEX]], :upper16:_tls_index
+; CHECK-NEXT: ldr [[INDEX:r[0-9]]], {{\[}}[[TLS_INDEX]]]
+
+; CHECK:      ldr [[TLS_POINTER:r[0-9]]], {{\[}}[[TEB]], #44]
+; CHECK-NEXT: ldr{{.w}} [[TLS:r[0-9]]], {{\[}}[[TLS_POINTER]], [[INDEX]], lsl #2]
+
+; CHECK-NEXT: movw [[SLOT:r[0-9]]], :lower16:o
+; CHECK-NEXT: movt [[SLOT]], :upper16:o
+
+; CHECK-NEXT: ldrb r0, {{\[}}[[TLS]], [[SLOT]]]
+