Add AArch64 as an experimental target.

This patch adds support for AArch64 (ARM's 64-bit architecture) to
LLVM in the "experimental" category. Currently, it won't be built
unless requested explicitly.

This initial commit should have support for:
    + Assembly of all scalar (i.e. non-NEON, non-Crypto) instructions
      (except the late addition CRC instructions).
    + CodeGen features required for C++03 and C99.
    + Compilation for the "small" memory model: code+static data <
      4GB.
    + Absolute and position-independent code.
    + GNU-style (i.e. "__thread") TLS.
    + Debugging information.

The principal omission, currently, is performance tuning.

This patch excludes the NEON support also reviewed due to an outbreak of
batshit insanity in our legal department. That will be committed soon bringing
the changes to precisely what has been approved.

Further reviews would be gratefully received.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174054 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 43 insertions, 0 deletions

diff --git a/lib/Target/AArch64/AArch64Subtarget.cpp b/lib/Target/AArch64/AArch64Subtarget.cpp
new file mode 100644
index 0000000000..d17b738209
--- /dev/null
+++ b/lib/Target/AArch64/AArch64Subtarget.cpp
@@ -0,0 +1,43 @@
+//===-- AArch64Subtarget.cpp - AArch64 Subtarget Information --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the AArch64 specific subclass of TargetSubtargetInfo.
+//
+//===----------------------------------------------------------------------===//
+
+#include "AArch64Subtarget.h"
+#include "AArch64RegisterInfo.h"
+#include "MCTargetDesc/AArch64MCTargetDesc.h"
+#include "llvm/IR/GlobalValue.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/ADT/SmallVector.h"
+
+#define GET_SUBTARGETINFO_TARGET_DESC
+#define GET_SUBTARGETINFO_CTOR
+#include "AArch64GenSubtargetInfo.inc"
+
+using namespace llvm;
+
+AArch64Subtarget::AArch64Subtarget(StringRef TT, StringRef CPU, StringRef FS)
+  : AArch64GenSubtargetInfo(TT, CPU, FS)
+  , HasNEON(true)
+  , HasCrypto(true)
+  , TargetTriple(TT) {
+
+  ParseSubtargetFeatures(CPU, FS);
+}
+
+bool AArch64Subtarget::GVIsIndirectSymbol(const GlobalValue *GV,
+                                          Reloc::Model RelocM) const {
+  if (RelocM == Reloc::Static)
+    return false;
+
+  return !GV->hasLocalLinkage() && !GV->hasHiddenVisibility();
+}