[X32] Add Triple::isX32(), use it.

So far, support for x86_64-linux-gnux32 has been handled by explicit
comparisons of Triple.getEnvironment() to GNUX32. This worked as long as
x86_64-linux-gnux32 was the only X32 environment to worry about, but we
now have x86_64-linux-muslx32 as well. To support this, this change adds
an isX32() function and uses it. It replaces all checks for GNUX32 or
MuslX32 by isX32(), except for the following:

- Triple::isGNUEnvironment() and Triple::isMusl() are supposed to treat
  GNUX32 and MuslX32 differently.
- computeTargetTriple() needs to be able to transform triples to add or
  remove X32 from the environment and needs to map GNU to GNUX32, and
  Musl to MuslX32.
- getMultiarchTriple() completely lacks any Musl support and retains the
  explicit check for GNUX32 as it can only return x86_64-linux-gnux32.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D103777

clang/lib/Basic/Targets/X86.h

@@ -661,7 +661,7 @@ class LLVM_LIBRARY_VISIBILITY X86_64TargetInfo : public X86TargetInfo {
 public:
   X86_64TargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
       : X86TargetInfo(Triple, Opts) {
-    const bool IsX32 = getTriple().getEnvironment() == llvm::Triple::GNUX32;
+    const bool IsX32 = getTriple().isX32();
     bool IsWinCOFF =
         getTriple().isOSWindows() && getTriple().isOSBinFormatCOFF();
     LongWidth = LongAlign = PointerWidth = PointerAlign = IsX32 ? 32 : 64;

clang/lib/Driver/Driver.cpp

@@ -519,14 +519,21 @@ static llvm::Triple computeTargetTriple(const Driver &D,
       AT = Target.get64BitArchVariant().getArch();
       if (Target.getEnvironment() == llvm::Triple::GNUX32)
         Target.setEnvironment(llvm::Triple::GNU);
+      else if (Target.getEnvironment() == llvm::Triple::MuslX32)
+        Target.setEnvironment(llvm::Triple::Musl);
     } else if (A->getOption().matches(options::OPT_mx32) &&
                Target.get64BitArchVariant().getArch() == llvm::Triple::x86_64) {
       AT = llvm::Triple::x86_64;
-      Target.setEnvironment(llvm::Triple::GNUX32);
+      if (Target.getEnvironment() == llvm::Triple::Musl)
+        Target.setEnvironment(llvm::Triple::MuslX32);
+      else
+        Target.setEnvironment(llvm::Triple::GNUX32);
     } else if (A->getOption().matches(options::OPT_m32)) {
       AT = Target.get32BitArchVariant().getArch();
       if (Target.getEnvironment() == llvm::Triple::GNUX32)
         Target.setEnvironment(llvm::Triple::GNU);
+      else if (Target.getEnvironment() == llvm::Triple::MuslX32)
+        Target.setEnvironment(llvm::Triple::Musl);
     } else if (A->getOption().matches(options::OPT_m16) &&
                Target.get32BitArchVariant().getArch() == llvm::Triple::x86) {
       AT = llvm::Triple::x86;

clang/lib/Driver/ToolChains/Gnu.cpp

@@ -294,7 +294,7 @@ static const char *getLDMOption(const llvm::Triple &T, const ArgList &Args) {
   case llvm::Triple::systemz:
     return "elf64_s390";
   case llvm::Triple::x86_64:
-    if (T.getEnvironment() == llvm::Triple::GNUX32)
+    if (T.isX32())
       return "elf32_x86_64";
     return "elf_x86_64";
   case llvm::Triple::ve:
@@ -725,7 +725,7 @@ void tools::gnutools::Assembler::ConstructJob(Compilation &C,
     CmdArgs.push_back("--32");
     break;
   case llvm::Triple::x86_64:
-    if (getToolChain().getTriple().getEnvironment() == llvm::Triple::GNUX32)
+    if (getToolChain().getTriple().isX32())
       CmdArgs.push_back("--x32");
     else
       CmdArgs.push_back("--64");
@@ -1733,7 +1733,7 @@ static bool findBiarchMultilibs(const Driver &D,
   // Determine default multilib from: 32, 64, x32
   // Also handle cases such as 64 on 32, 32 on 64, etc.
   enum { UNKNOWN, WANT32, WANT64, WANTX32 } Want = UNKNOWN;
-  const bool IsX32 = TargetTriple.getEnvironment() == llvm::Triple::GNUX32;
+  const bool IsX32 = TargetTriple.isX32();
   if (TargetTriple.isArch32Bit() && !NonExistent(Alt32))
     Want = WANT64;
   else if (TargetTriple.isArch64Bit() && IsX32 && !NonExistent(Altx32))
@@ -2339,7 +2339,7 @@ void Generic_GCC::GCCInstallationDetector::AddDefaultGCCPrefixes(
     TripleAliases.append(begin(AVRTriples), end(AVRTriples));
     break;
   case llvm::Triple::x86_64:
-    if (TargetTriple.getEnvironment() == llvm::Triple::GNUX32) {
+    if (TargetTriple.isX32()) {
       LibDirs.append(begin(X32LibDirs), end(X32LibDirs));
       TripleAliases.append(begin(X32Triples), end(X32Triples));
       BiarchLibDirs.append(begin(X86_64LibDirs), end(X86_64LibDirs));

clang/lib/Driver/ToolChains/Linux.cpp

@@ -166,8 +166,7 @@ static StringRef getOSLibDir(const llvm::Triple &Triple, const ArgList &Args) {
       Triple.getArch() == llvm::Triple::sparc)
     return "lib32";
 
-  if (Triple.getArch() == llvm::Triple::x86_64 &&
-      Triple.getEnvironment() == llvm::Triple::GNUX32)
+  if (Triple.getArch() == llvm::Triple::x86_64 && Triple.isX32())
     return "libx32";
 
   if (Triple.getArch() == llvm::Triple::riscv32)
@@ -402,9 +401,7 @@ std::string Linux::getDynamicLinker(const ArgList &Args) const {
       ArchName = "i386";
       break;
     case llvm::Triple::x86_64:
-      ArchName = Triple.getEnvironment() == llvm::Triple::MuslX32
-                     ? "x32"
-                     : Triple.getArchName().str();
+      ArchName = Triple.isX32() ? "x32" : Triple.getArchName().str();
       break;
     default:
       ArchName = Triple.getArchName().str();
@@ -515,7 +512,7 @@ std::string Linux::getDynamicLinker(const ArgList &Args) const {
     Loader = "ld-linux.so.2";
     break;
   case llvm::Triple::x86_64: {
-    bool X32 = Triple.getEnvironment() == llvm::Triple::GNUX32;
+    bool X32 = Triple.isX32();
 
     LibDir = X32 ? "libx32" : "lib64";
     Loader = X32 ? "ld-linux-x32.so.2" : "ld-linux-x86-64.so.2";

clang/test/Driver/linux-cross.cpp

@@ -136,4 +136,6 @@
 
 // RUN: %clang -### %s --target=x86_64-linux-muslx32 --sysroot= \
 // RUN:   --stdlib=platform --rtlib=platform 2>&1 | FileCheck %s --check-prefix=MUSL_X32
+// RUN: %clang -### %s --target=i686-linux-musl -mx32 --sysroot= \
+// RUN:   --stdlib=platform --rtlib=platform 2>&1 | FileCheck %s --check-prefix=MUSL_X32
 // MUSL_X32: "-dynamic-linker" "/lib/ld-musl-x32.so.1"

llvm/include/llvm/ADT/Triple.h

@@ -805,6 +805,12 @@ public:
            getSubArch() == Triple::AArch64SubArch_arm64e;
   }
 
+  /// Tests whether the target is X32.
+  bool isX32() const {
+    EnvironmentType Env = getEnvironment();
+    return Env == Triple::GNUX32 || Env == Triple::MuslX32;
+  }
+
   /// Tests whether the target supports comdat
   bool supportsCOMDAT() const {
     return !(isOSBinFormatMachO() || isOSBinFormatXCOFF());

llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp

@@ -1631,7 +1631,7 @@ MCAsmBackend *llvm::createX86_64AsmBackend(const Target &T,
 
   uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TheTriple.getOS());
 
-  if (TheTriple.getEnvironment() == Triple::GNUX32)
+  if (TheTriple.isX32())
     return new ELFX86_X32AsmBackend(T, OSABI, STI);
   return new ELFX86_64AsmBackend(T, OSABI, STI);
 }

llvm/lib/Target/X86/MCTargetDesc/X86MCAsmInfo.cpp

@@ -81,7 +81,7 @@ void X86ELFMCAsmInfo::anchor() { }
 
 X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) {
   bool is64Bit = T.getArch() == Triple::x86_64;
-  bool isX32 = T.getEnvironment() == Triple::GNUX32;
+  bool isX32 = T.isX32();
 
   // 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

llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp

@@ -1231,8 +1231,7 @@ bool X86MCCodeEmitter::emitREXPrefix(int MemOperand, const MCInst &MI,
           // FIXME: The caller of determineREXPrefix slaps this prefix onto
           // anything that returns non-zero.
           REX |= 0x40; // REX fixed encoding prefix
-      } else if (MO.isExpr() &&
-                 STI.getTargetTriple().getEnvironment() == Triple::GNUX32) {
+      } else if (MO.isExpr() && STI.getTargetTriple().isX32()) {
         // GOTTPOFF and TLSDESC relocations require a REX prefix to allow
         // linker optimizations: even if the instructions we see may not require
         // any prefix, they may be replaced by instructions that do. This is

llvm/lib/Target/X86/X86AsmPrinter.cpp

@@ -643,8 +643,7 @@ void X86AsmPrinter::emitStartOfAsmFile(Module &M) {
       OutStreamer->SwitchSection(Nt);
 
       // Emitting note header.
-      const int WordSize =
-          TT.isArch64Bit() && TT.getEnvironment() != Triple::GNUX32 ? 8 : 4;
+      const int WordSize = TT.isArch64Bit() && !TT.isX32() ? 8 : 4;
       emitAlignment(WordSize == 4 ? Align(4) : Align(8));
       OutStreamer->emitIntValue(4, 4 /*size*/); // data size for "GNU\0"
       OutStreamer->emitIntValue(8 + WordSize, 4 /*size*/); // Elf_Prop size

llvm/lib/Target/X86/X86RegisterInfo.cpp

@@ -62,7 +62,7 @@ X86RegisterInfo::X86RegisterInfo(const Triple &TT)
     // This matches the simplified 32-bit pointer code in the data layout
     // computation.
     // FIXME: Should use the data layout?
-    bool Use64BitReg = TT.getEnvironment() != Triple::GNUX32;
+    bool Use64BitReg = !TT.isX32();
     StackPtr = Use64BitReg ? X86::RSP : X86::ESP;
     FramePtr = Use64BitReg ? X86::RBP : X86::EBP;
     BasePtr = Use64BitReg ? X86::RBX : X86::EBX;

llvm/lib/Target/X86/X86Subtarget.h

@@ -610,14 +610,12 @@ public:
 
   /// Is this x86_64 with the ILP32 programming model (x32 ABI)?
   bool isTarget64BitILP32() const {
-    return In64BitMode && (TargetTriple.getEnvironment() == Triple::GNUX32 ||
-                           TargetTriple.isOSNaCl());
+    return In64BitMode && (TargetTriple.isX32() || TargetTriple.isOSNaCl());
   }
 
   /// Is this x86_64 with the LP64 programming model (standard AMD64, no x32)?
   bool isTarget64BitLP64() const {
-    return In64BitMode && (TargetTriple.getEnvironment() != Triple::GNUX32 &&
-                           !TargetTriple.isOSNaCl());
+    return In64BitMode && (!TargetTriple.isX32() && !TargetTriple.isOSNaCl());
   }
 
   PICStyles::Style getPICStyle() const { return PICStyle; }

llvm/lib/Target/X86/X86TargetMachine.cpp

@@ -110,9 +110,7 @@ static std::string computeDataLayout(const Triple &TT) {
 
   Ret += DataLayout::getManglingComponent(TT);
   // X86 and x32 have 32 bit pointers.
-  if ((TT.isArch64Bit() &&
-       (TT.getEnvironment() == Triple::GNUX32 || TT.isOSNaCl())) ||
-      !TT.isArch64Bit())
+  if (!TT.isArch64Bit() || TT.isX32() || TT.isOSNaCl())
     Ret += "-p:32:32";
 
   // Address spaces for 32 bit signed, 32 bit unsigned, and 64 bit pointers.

llvm/test/CodeGen/X86/x32-lea-1.ll

@@ -1,5 +1,6 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc < %s -mtriple=x86_64-linux-gnux32 -O0 | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64-linux-muslx32 -O0 | FileCheck %s
 
 define void @foo(i32** %p) {
 ; CHECK-LABEL: foo: