[ARM] Create SubtargetFeatures from build attrs

An ELFObjectFile can now create SubtargetFeatures from the available
ARM build attributes, in a similar manner to MIPS. I've moved the
MIPS code into its own function and the ARM handler also has a
separate function.

Differential Revision: https://reviews.llvm.org/D28291

llvm-svn: 292403

1 files changed, 153 insertions, 42 deletions

diff --git a/llvm/lib/Object/ELFObjectFile.cpp b/llvm/lib/Object/ELFObjectFile.cpp
index fb133c254d0..3f8c81c8e91 100644
--- a/llvm/lib/Object/ELFObjectFile.cpp
+++ b/llvm/lib/Object/ELFObjectFile.cpp
@@ -12,6 +12,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Object/ELFObjectFile.h"
+#include "llvm/Support/ARMBuildAttributes.h"
+#include "llvm/Support/ARMAttributeParser.h"
 #include "llvm/Support/MathExtras.h"
 
 namespace llvm {
@@ -55,68 +57,177 @@ ObjectFile::createELFObjectFile(MemoryBufferRef Obj) {
   return std::move(R);
 }
 
-SubtargetFeatures ELFObjectFileBase::getFeatures() const {
-  switch (getEMachine()) {
-  case ELF::EM_MIPS: {
-    SubtargetFeatures Features;
-    unsigned PlatformFlags;
-    getPlatformFlags(PlatformFlags);
+SubtargetFeatures ELFObjectFileBase::getMIPSFeatures() const {
+  SubtargetFeatures Features;
+  unsigned PlatformFlags;
+  getPlatformFlags(PlatformFlags);
+
+  switch (PlatformFlags & ELF::EF_MIPS_ARCH) {
+  case ELF::EF_MIPS_ARCH_1:
+    break;
+  case ELF::EF_MIPS_ARCH_2:
+    Features.AddFeature("mips2");
+    break;
+  case ELF::EF_MIPS_ARCH_3:
+    Features.AddFeature("mips3");
+    break;
+  case ELF::EF_MIPS_ARCH_4:
+    Features.AddFeature("mips4");
+    break;
+  case ELF::EF_MIPS_ARCH_5:
+    Features.AddFeature("mips5");
+    break;
+  case ELF::EF_MIPS_ARCH_32:
+    Features.AddFeature("mips32");
+    break;
+  case ELF::EF_MIPS_ARCH_64:
+    Features.AddFeature("mips64");
+    break;
+  case ELF::EF_MIPS_ARCH_32R2:
+    Features.AddFeature("mips32r2");
+    break;
+  case ELF::EF_MIPS_ARCH_64R2:
+    Features.AddFeature("mips64r2");
+    break;
+  case ELF::EF_MIPS_ARCH_32R6:
+    Features.AddFeature("mips32r6");
+    break;
+  case ELF::EF_MIPS_ARCH_64R6:
+    Features.AddFeature("mips64r6");
+    break;
+  default:
+    llvm_unreachable("Unknown EF_MIPS_ARCH value");
+  }
+
+  switch (PlatformFlags & ELF::EF_MIPS_MACH) {
+  case ELF::EF_MIPS_MACH_NONE:
+    // No feature associated with this value.
+    break;
+  case ELF::EF_MIPS_MACH_OCTEON:
+    Features.AddFeature("cnmips");
+    break;
+  default:
+    llvm_unreachable("Unknown EF_MIPS_ARCH value");
+  }
+
+  if (PlatformFlags & ELF::EF_MIPS_ARCH_ASE_M16)
+    Features.AddFeature("mips16");
+  if (PlatformFlags & ELF::EF_MIPS_MICROMIPS)
+    Features.AddFeature("micromips");
+
+  return Features;
+}
 
-    switch (PlatformFlags & ELF::EF_MIPS_ARCH) {
-    case ELF::EF_MIPS_ARCH_1:
+SubtargetFeatures ELFObjectFileBase::getARMFeatures() const {
+  SubtargetFeatures Features;
+  ARMAttributeParser Attributes;
+  std::error_code EC = getBuildAttributes(Attributes);
+  if (EC)
+    return SubtargetFeatures();
+
+  // both ARMv7-M and R have to support thumb hardware div
+  bool isV7 = false;
+  if (Attributes.hasAttribute(ARMBuildAttrs::CPU_arch))
+    isV7 = Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch)
+      == ARMBuildAttrs::v7;
+
+  if (Attributes.hasAttribute(ARMBuildAttrs::CPU_arch_profile)) {
+    switch(Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch_profile)) {
+    case ARMBuildAttrs::ApplicationProfile:
+      Features.AddFeature("aclass");
       break;
-    case ELF::EF_MIPS_ARCH_2:
-      Features.AddFeature("mips2");
+    case ARMBuildAttrs::RealTimeProfile:
+      Features.AddFeature("rclass");
+      if (isV7)
+        Features.AddFeature("hwdiv");
       break;
-    case ELF::EF_MIPS_ARCH_3:
-      Features.AddFeature("mips3");
+    case ARMBuildAttrs::MicroControllerProfile:
+      Features.AddFeature("mclass");
+      if (isV7)
+        Features.AddFeature("hwdiv");
       break;
-    case ELF::EF_MIPS_ARCH_4:
-      Features.AddFeature("mips4");
+    }
+  }
+
+  if (Attributes.hasAttribute(ARMBuildAttrs::THUMB_ISA_use)) {
+    switch(Attributes.getAttributeValue(ARMBuildAttrs::THUMB_ISA_use)) {
+    default:
       break;
-    case ELF::EF_MIPS_ARCH_5:
-      Features.AddFeature("mips5");
+    case ARMBuildAttrs::Not_Allowed:
+      Features.AddFeature("thumb", false);
+      Features.AddFeature("thumb2", false);
       break;
-    case ELF::EF_MIPS_ARCH_32:
-      Features.AddFeature("mips32");
+    case ARMBuildAttrs::AllowThumb32:
+      Features.AddFeature("thumb2");
       break;
-    case ELF::EF_MIPS_ARCH_64:
-      Features.AddFeature("mips64");
+    }
+  }
+
+  if (Attributes.hasAttribute(ARMBuildAttrs::FP_arch)) {
+    switch(Attributes.getAttributeValue(ARMBuildAttrs::FP_arch)) {
+    default:
       break;
-    case ELF::EF_MIPS_ARCH_32R2:
-      Features.AddFeature("mips32r2");
+    case ARMBuildAttrs::Not_Allowed:
+      Features.AddFeature("vfp2", false);
+      Features.AddFeature("vfp3", false);
+      Features.AddFeature("vfp4", false);
       break;
-    case ELF::EF_MIPS_ARCH_64R2:
-      Features.AddFeature("mips64r2");
+    case ARMBuildAttrs::AllowFPv2:
+      Features.AddFeature("vfp2");
       break;
-    case ELF::EF_MIPS_ARCH_32R6:
-      Features.AddFeature("mips32r6");
+    case ARMBuildAttrs::AllowFPv3A:
+    case ARMBuildAttrs::AllowFPv3B:
+      Features.AddFeature("vfp3");
       break;
-    case ELF::EF_MIPS_ARCH_64R6:
-      Features.AddFeature("mips64r6");
+    case ARMBuildAttrs::AllowFPv4A:
+    case ARMBuildAttrs::AllowFPv4B:
+      Features.AddFeature("vfp4");
       break;
-    default:
-      llvm_unreachable("Unknown EF_MIPS_ARCH value");
     }
+  }
 
-    switch (PlatformFlags & ELF::EF_MIPS_MACH) {
-    case ELF::EF_MIPS_MACH_NONE:
-      // No feature associated with this value.
+  if (Attributes.hasAttribute(ARMBuildAttrs::Advanced_SIMD_arch)) {
+    switch(Attributes.getAttributeValue(ARMBuildAttrs::Advanced_SIMD_arch)) {
+    default:
+      break;
+    case ARMBuildAttrs::Not_Allowed:
+      Features.AddFeature("neon", false);
+      Features.AddFeature("fp16", false);
       break;
-    case ELF::EF_MIPS_MACH_OCTEON:
-      Features.AddFeature("cnmips");
+    case ARMBuildAttrs::AllowNeon:
+      Features.AddFeature("neon");
       break;
+    case ARMBuildAttrs::AllowNeon2:
+      Features.AddFeature("neon");
+      Features.AddFeature("fp16");
+      break;
+    }
+  }
+
+  if (Attributes.hasAttribute(ARMBuildAttrs::DIV_use)) {
+    switch(Attributes.getAttributeValue(ARMBuildAttrs::DIV_use)) {
     default:
-      llvm_unreachable("Unknown EF_MIPS_ARCH value");
+      break;
+    case ARMBuildAttrs::DisallowDIV:
+      Features.AddFeature("hwdiv", false);
+      Features.AddFeature("hwdiv-arm", false);
+      break;
+    case ARMBuildAttrs::AllowDIVExt:
+      Features.AddFeature("hwdiv");
+      Features.AddFeature("hwdiv-arm");
+      break;
     }
+  }
 
-    if (PlatformFlags & ELF::EF_MIPS_ARCH_ASE_M16)
-      Features.AddFeature("mips16");
-    if (PlatformFlags & ELF::EF_MIPS_MICROMIPS)
-      Features.AddFeature("micromips");
+  return Features;
+}
 
-    return Features;
-  }
+SubtargetFeatures ELFObjectFileBase::getFeatures() const {
+  switch (getEMachine()) {
+  case ELF::EM_MIPS:
+    return getMIPSFeatures();
+  case ELF::EM_ARM:
+    return getARMFeatures();
   default:
     return SubtargetFeatures();
   }