[PowerPC] Support powerpc64le as a syntax-checking target.

This patch provides basic support for powerpc64le as an LLVM target.
However, use of this target will not actually generate little-endian
code.  Instead, use of the target will cause the correct little-endian
built-in defines to be generated, so that code that tests for
__LITTLE_ENDIAN__, for example, will be correctly parsed for
syntax-only testing.  Code generation will otherwise be the same as
powerpc64 (big-endian), for now.

The patch leaves open the possibility of creating a little-endian
PowerPC64 back end, but there is no immediate intent to create such a
thing.

The LLVM portions of this patch simply add ppc64le coverage everywhere
that ppc64 coverage currently exists.  There is nothing of any import
worth testing until such time as little-endian code generation is
implemented.  In the corresponding Clang patch, there is a new test
case variant to ensure that correct built-in defines for little-endian
code are generated.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187179 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/Triple.cpp

@@ -28,6 +28,7 @@ const char *Triple::getArchTypeName(ArchType Kind) {
   case mips64el:return "mips64el";
   case msp430:  return "msp430";
   case ppc64:   return "powerpc64";
+  case ppc64le: return "powerpc64le";
   case ppc:     return "powerpc";
   case r600:    return "r600";
   case sparc:   return "sparc";
@@ -60,6 +61,7 @@ const char *Triple::getArchTypePrefix(ArchType Kind) {
   case thumb:   return "arm";
 
   case ppc64:
+  case ppc64le:
   case ppc:     return "ppc";
 
   case mips:
@@ -168,6 +170,7 @@ Triple::ArchType Triple::getArchTypeForLLVMName(StringRef Name) {
     .Case("ppc64", ppc64)
     .Case("ppc32", ppc)
     .Case("ppc", ppc)
+    .Case("ppc64le", ppc64le)
     .Case("r600", r600)
     .Case("hexagon", hexagon)
     .Case("sparc", sparc)
@@ -197,6 +200,7 @@ const char *Triple::getArchNameForAssembler() {
     .Case("x86_64", "x86_64")
     .Case("powerpc", "ppc")
     .Case("powerpc64", "ppc64")
+    .Case("powerpc64le", "ppc64le")
     .Case("arm", "arm")
     .Cases("armv4t", "thumbv4t", "armv4t")
     .Cases("armv5", "armv5e", "thumbv5", "thumbv5e", "armv5")
@@ -220,6 +224,7 @@ static Triple::ArchType parseArch(StringRef ArchName) {
     .Cases("amd64", "x86_64", Triple::x86_64)
     .Case("powerpc", Triple::ppc)
     .Cases("powerpc64", "ppu", Triple::ppc64)
+    .Case("powerpc64le", Triple::ppc64le)
     .Case("aarch64", Triple::aarch64)
     .Cases("arm", "xscale", Triple::arm)
     // FIXME: It would be good to replace these with explicit names for all the
@@ -690,6 +695,7 @@ static unsigned getArchPointerBitWidth(llvm::Triple::ArchType Arch) {
   case llvm::Triple::mips64el:
   case llvm::Triple::nvptx64:
   case llvm::Triple::ppc64:
+  case llvm::Triple::ppc64le:
   case llvm::Triple::sparcv9:
   case llvm::Triple::systemz:
   case llvm::Triple::x86_64:
@@ -718,6 +724,7 @@ Triple Triple::get32BitArchVariant() const {
   case Triple::aarch64:
   case Triple::msp430:
   case Triple::systemz:
+  case Triple::ppc64le:
     T.setArch(UnknownArch);
     break;
 
@@ -772,6 +779,7 @@ Triple Triple::get64BitArchVariant() const {
   case Triple::mips64el:
   case Triple::nvptx64:
   case Triple::ppc64:
+  case Triple::ppc64le:
   case Triple::sparcv9:
   case Triple::systemz:
   case Triple::x86_64: