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

2 files changed, 22 insertions, 1 deletions

diff --git a/lib/MC/MCELFStreamer.cpp b/lib/MC/MCELFStreamer.cpp
index e5b749e28b..c4c8e6e4e7 100644
--- a/lib/MC/MCELFStreamer.cpp
+++ b/lib/MC/MCELFStreamer.cpp
@@ -300,7 +300,9 @@ void MCELFStreamer::EmitFileDirective(StringRef Filename) {
 
 void  MCELFStreamer::fixSymbolsInTLSFixups(const MCExpr *expr) {
   switch (expr->getKind()) {
-  case MCExpr::Target: llvm_unreachable("Can't handle target exprs yet!");
+  case MCExpr::Target:
+    cast<MCTargetExpr>(expr)->fixELFSymbolsInTLSFixups(getAssembler());
+    break;
   case MCExpr::Constant:
     break;
 
diff --git a/lib/MC/MCObjectFileInfo.cpp b/lib/MC/MCObjectFileInfo.cpp
index 1f5548f779..ae0abde86a 100644
--- a/lib/MC/MCObjectFileInfo.cpp
+++ b/lib/MC/MCObjectFileInfo.cpp
@@ -256,6 +256,25 @@ void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
       TTypeEncoding = (CMModel == CodeModel::Small)
         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
     }
+  }  else if (T.getArch() ==  Triple::aarch64) {
+    FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
+
+    // The small model guarantees static code/data size < 4GB, but not where it
+    // will be in memory. Most of these could end up >2GB away so even a signed
+    // pc-relative 32-bit address is insufficient, theoretically.
+    if (RelocM == Reloc::PIC_) {
+      PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+        dwarf::DW_EH_PE_sdata8;
+      LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
+      FDEEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
+      TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+        dwarf::DW_EH_PE_sdata8;
+    } else {
+      PersonalityEncoding = dwarf::DW_EH_PE_absptr;
+      LSDAEncoding = dwarf::DW_EH_PE_absptr;
+      FDEEncoding = dwarf::DW_EH_PE_udata4;
+      TTypeEncoding = dwarf::DW_EH_PE_absptr;
+    }
   } else if (T.getArch() == Triple::ppc64) {
     PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
       dwarf::DW_EH_PE_udata8;