[ARM] add target arch definitions for 8.1-M and MVE

This adds:
- LLVM subtarget features to make all the new instructions conditional on,
- CPU and FPU names for use on clang's command line, with default FPUs set
  so that "armv8.1-m.main+fp" and "armv8.1-m.main+fp.dp" will select the right
  FPU features,
- architecture extension names "mve" and "mve.fp",
- ABI build attribute support for v8.1-M (a new value for Tag_CPU_arch) and MVE
  (a new actual tag).

Patch mostly by Simon Tatham.

Differential Revision: https://reviews.llvm.org/D60698

llvm-svn: 362090

1 files changed, 18 insertions, 0 deletions

diff --git a/llvm/lib/Object/ELFObjectFile.cpp b/llvm/lib/Object/ELFObjectFile.cpp
index 1c3469b5971..c7b71579304 100644
--- a/llvm/lib/Object/ELFObjectFile.cpp
+++ b/llvm/lib/Object/ELFObjectFile.cpp
@@ -230,6 +230,24 @@ SubtargetFeatures ELFObjectFileBase::getARMFeatures() const {
     }
   }
 
+  if (Attributes.hasAttribute(ARMBuildAttrs::MVE_arch)) {
+    switch(Attributes.getAttributeValue(ARMBuildAttrs::MVE_arch)) {
+    default:
+      break;
+    case ARMBuildAttrs::Not_Allowed:
+      Features.AddFeature("mve", false);
+      Features.AddFeature("mve.fp", false);
+      break;
+    case ARMBuildAttrs::AllowMVEInteger:
+      Features.AddFeature("mve.fp", false);
+      Features.AddFeature("mve");
+      break;
+    case ARMBuildAttrs::AllowMVEIntegerAndFloat:
+      Features.AddFeature("mve.fp");
+      break;
+    }
+  }
+
   if (Attributes.hasAttribute(ARMBuildAttrs::DIV_use)) {
     switch(Attributes.getAttributeValue(ARMBuildAttrs::DIV_use)) {
     default: