Initial patch for x32 ABI support.

Add the x32 environment kind to the triple, and separate the concept of
pointer size and callee save stack slot size, since they're not equal
on x32.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173175 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ADT/Triple.h

@@ -111,6 +111,7 @@ class Triple {
     GNU,
     GNUEABI,
     GNUEABIHF,
+    GNUX32,
     EABI,
     MachO,
     Android,

include/llvm/MC/MCAsmInfo.h

@@ -48,6 +48,11 @@ namespace llvm {
     ///               Default is 4.
     unsigned PointerSize;
 
+    /// CalleeSaveStackSlotSize - Size of the stack slot reserved for
+    ///                           callee-saved registers, in bytes.
+    ///                           Default is same as pointer size.
+    unsigned CalleeSaveStackSlotSize;
+
     /// IsLittleEndian - True if target is little endian.
     ///                  Default is true.
     bool IsLittleEndian;
@@ -343,7 +348,18 @@ namespace llvm {
       return PointerSize;
     }
 
-    /// islittleendian - True if the target is little endian.
+    /// getCalleeSaveStackSlotSize - Get the callee-saved register stack slot
+    /// size in bytes.
+    unsigned getCalleeSaveStackSlotSize() const {
+      // If a target doesn't explicitly initialize this member, PointerSize is
+      // used by default.
+      if (CalleeSaveStackSlotSize == 0)
+        return PointerSize;
+      else
+        return CalleeSaveStackSlotSize;
+    }
+
+    /// isLittleEndian - True if the target is little endian.
     bool isLittleEndian() const {
       return IsLittleEndian;
     }

lib/MC/MCAsmInfo.cpp

@@ -24,6 +24,8 @@ using namespace llvm;
 
 MCAsmInfo::MCAsmInfo() {
   PointerSize = 4;
+  CalleeSaveStackSlotSize = 0; // 0 means PointerSize is used in getter.
+
   IsLittleEndian = true;
   StackGrowsUp = false;
   HasSubsectionsViaSymbols = false;

lib/MC/MCDwarf.cpp

@@ -792,7 +792,7 @@ void MCGenDwarfLabelEntry::Make(MCSymbol *Symbol, MCStreamer *MCOS,
 static int getDataAlignmentFactor(MCStreamer &streamer) {
   MCContext &context = streamer.getContext();
   const MCAsmInfo &asmInfo = context.getAsmInfo();
-  int size = asmInfo.getPointerSize();
+  int size = asmInfo.getCalleeSaveStackSlotSize();
   if (asmInfo.isStackGrowthDirectionUp())
     return size;
   else

lib/Support/Triple.cpp

@@ -140,6 +140,7 @@ const char *Triple::getEnvironmentTypeName(EnvironmentType Kind) {
   case GNU: return "gnu";
   case GNUEABIHF: return "gnueabihf";
   case GNUEABI: return "gnueabi";
+  case GNUX32: return "gnux32";
   case EABI: return "eabi";
   case MachO: return "macho";
   case Android: return "android";
@@ -284,6 +285,7 @@ static Triple::EnvironmentType parseEnvironment(StringRef EnvironmentName) {
     .StartsWith("eabi", Triple::EABI)
     .StartsWith("gnueabihf", Triple::GNUEABIHF)
     .StartsWith("gnueabi", Triple::GNUEABI)
+    .StartsWith("gnux32", Triple::GNUX32)
     .StartsWith("gnu", Triple::GNU)
     .StartsWith("macho", Triple::MachO)
     .StartsWith("android", Triple::Android)

lib/Target/X86/MCTargetDesc/X86MCAsmInfo.cpp

@@ -44,7 +44,7 @@ void X86MCAsmInfoDarwin::anchor() { }
 X86MCAsmInfoDarwin::X86MCAsmInfoDarwin(const Triple &T) {
   bool is64Bit = T.getArch() == Triple::x86_64;
   if (is64Bit)
-    PointerSize = 8;
+    PointerSize = CalleeSaveStackSlotSize = 8;
 
   AssemblerDialect = AsmWriterFlavor;
 
@@ -76,8 +76,16 @@ X86_64MCAsmInfoDarwin::X86_64MCAsmInfoDarwin(const Triple &Triple)
 void X86ELFMCAsmInfo::anchor() { }
 
 X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) {
-  if (T.getArch() == Triple::x86_64)
-    PointerSize = 8;
+  bool is64Bit = T.getArch() == Triple::x86_64;
+  bool isX32 = T.getEnvironment() == Triple::GNUX32;
+
+  // For ELF, x86-64 pointer size depends on the ABI.
+  // For x86-64 without the x32 ABI, pointer size is 8. For x86 and for x86-64
+  // with the x32 ABI, pointer size remains the default 4.
+  PointerSize = (is64Bit && !isX32) ? 8 : 4;
+
+  // OTOH, stack slot size is always 8 for x86-64, even with the x32 ABI.
+  CalleeSaveStackSlotSize = is64Bit ? 8 : 4;
 
   AssemblerDialect = AsmWriterFlavor;