[ARM] Add +feature names to TargetParser extensions table

[bsmith]

Summary

In order to support the AArch64 +feature syntax used in -mcpu/-march on ARM, the TargetParser needs to be taught how to map the extension names to the LLVM feature names.

This change adds this support which will be used in my next (clang) patch to support this type of targeting. For now we just enable use of +crc/+nocrc since this is the only optional extension we want to expose on the command line.

[rengolin]

include/llvm/Support/ARMTargetParser.def

113

I thought crypto would have, too.

lib/Support/TargetParser.cpp

335

Most extensions don't have a name, it'd be good to avoid constructing a StringRef out of a nullptr + another out of "no" + nullptr for every extension but one.

[bsmith]

Only call getName/getNegName if the respective feature name is not nullptr. Also enable use of +crypto, I had originally omitted this due to it being specified in -mfpu, but I see no reason why it can't be here also.

[rengolin]

LGTM, thanks!

[bsmith]

Thanks, committed as r253470.

include/llvm/Support/ARMTargetParser.def

 #undef ARM_ARCH
 
 #ifndef ARM_ARCH_EXT_NAME
-#define ARM_ARCH_EXT_NAME(NAME, ID)
+#define ARM_ARCH_EXT_NAME(NAME, ID, FEATURE, NEGFEATURE)
 #endif
-ARM_ARCH_EXT_NAME("invalid", AEK_INVALID)
-ARM_ARCH_EXT_NAME("none", AEK_NONE)
-ARM_ARCH_EXT_NAME("crc", AEK_CRC)
-ARM_ARCH_EXT_NAME("crypto", AEK_CRYPTO)
-ARM_ARCH_EXT_NAME("fp", AEK_FP)
-ARM_ARCH_EXT_NAME("idiv", (AEK_HWDIVARM | AEK_HWDIV))
-ARM_ARCH_EXT_NAME("mp", AEK_MP)
-ARM_ARCH_EXT_NAME("simd", AEK_SIMD)
-ARM_ARCH_EXT_NAME("sec", AEK_SEC)
-ARM_ARCH_EXT_NAME("virt", AEK_VIRT)
-ARM_ARCH_EXT_NAME("os", AEK_OS)
-ARM_ARCH_EXT_NAME("iwmmxt", AEK_IWMMXT)
-ARM_ARCH_EXT_NAME("iwmmxt2", AEK_IWMMXT2)
-ARM_ARCH_EXT_NAME("maverick", AEK_MAVERICK)
-ARM_ARCH_EXT_NAME("xscale", AEK_XSCALE)
+// FIXME: This would be nicer were it tablegen
+ARM_ARCH_EXT_NAME("invalid",  AEK_INVALID,  nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("none",     AEK_NONE,     nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("crc",      AEK_CRC,      "+crc",   "-crc")
+ARM_ARCH_EXT_NAME("crypto",   AEK_CRYPTO,   "+crypto","-crypto")
+ARM_ARCH_EXT_NAME("fp",       AEK_FP,       nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("idiv",     (AEK_HWDIVARM | AEK_HWDIV), nullptr, nullptr)
+ARM_ARCH_EXT_NAME("mp",       AEK_MP,       nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("simd",     AEK_SIMD,     nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("sec",      AEK_SEC,      nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("virt",     AEK_VIRT,     nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("os",       AEK_OS,       nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("iwmmxt",   AEK_IWMMXT,   nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("iwmmxt2",  AEK_IWMMXT2,  nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("maverick", AEK_MAVERICK, nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("xscale",   AEK_XSCALE,   nullptr,  nullptr)
 #undef ARM_ARCH_EXT_NAME
 
 #ifndef ARM_HW_DIV_NAME

include/llvm/Support/TargetParser.h

 StringRef getCPUAttr(unsigned ArchKind);
 StringRef getSubArch(unsigned ArchKind);
 StringRef getArchExtName(unsigned ArchExtKind);
+const char *getArchExtFeature(StringRef ArchExt);
 StringRef getHWDivName(unsigned HWDivKind);
 
 // Information by Name

lib/Support/TargetParser.cpp

 #include "llvm/Support/TargetParser.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSwitch.h"
+#include "llvm/ADT/Twine.h"
 #include <cctype>
 
 using namespace llvm;

   const char *NameCStr;
   size_t NameLength;
   unsigned ID;
+  const char *Feature;
+  const char *NegFeature;
 
   StringRef getName() const { return StringRef(NameCStr, NameLength); }
+  StringRef getNegName() const { return (Twine("no") + getName()).str(); }
 } ARCHExtNames[] = {
-#define ARM_ARCH_EXT_NAME(NAME, ID) { NAME, sizeof(NAME) - 1, ID },
+#define ARM_ARCH_EXT_NAME(NAME, ID, FEATURE, NEGFEATURE) \
+  { NAME, sizeof(NAME) - 1, ID, FEATURE, NEGFEATURE },
 #include "llvm/Support/ARMTargetParser.def"
 };
 

   return StringRef();
 }
 
+const char *llvm::ARM::getArchExtFeature(StringRef ArchExt) {
+  for (const auto AE : ARCHExtNames) {
+    if (AE.Feature && ArchExt == AE.getName())
+      return AE.Feature;
+    else if (AE.NegFeature && ArchExt == AE.getNegName())
+      return AE.NegFeature;
+  }
+
+  return nullptr;
+}
+
 StringRef llvm::ARM::getHWDivName(unsigned HWDivKind) {
   for (const auto D : HWDivNames) {
     if (HWDivKind == D.ID)