[NFC] isOSGlibc: musl is not glibc. (#171734)

Previously, `isOSGlibc()` was returning true for musl triples as well.
This commit changes `isOSGlibc()` to return false for musl triples, and
updates all existing `isOSGlibc()` checks to call `isOSGlibc() ||
isMusl()`, in order to preserve existing behaviour.

Author: hvdijk

clang/lib/Basic/Targets/PPC.h

@@ -368,15 +368,15 @@ class LLVM_LIBRARY_VISIBILITY PPCTargetInfo : public TargetInfo {
   bool supportsCpuSupports() const override {
     llvm::Triple Triple = getTriple();
     // AIX 7.2 is the minimum requirement to support __builtin_cpu_supports().
-    return Triple.isOSGlibc() ||
+    return Triple.isOSGlibc() || Triple.isMusl() ||
            (Triple.isOSAIX() &&
             !Triple.isOSVersionLT(MINIMUM_AIX_OS_MAJOR, MINIMUM_AIX_OS_MINOR));
   }
 
   bool supportsCpuIs() const override {
     llvm::Triple Triple = getTriple();
     // AIX 7.2 is the minimum requirement to support __builtin_cpu_is().
-    return Triple.isOSGlibc() ||
+    return Triple.isOSGlibc() || Triple.isMusl() ||
            (Triple.isOSAIX() &&
             !Triple.isOSVersionLT(MINIMUM_AIX_OS_MAJOR, MINIMUM_AIX_OS_MINOR));
   }

llvm/include/llvm/TargetParser/Triple.h

@@ -769,7 +769,7 @@ class Triple {
   bool isOSGlibc() const {
     return (getOS() == Triple::Linux || getOS() == Triple::KFreeBSD ||
             getOS() == Triple::Hurd) &&
-           !isAndroid();
+           !isAndroid() && !isMusl();
   }
 
   /// Tests whether the OS is AIX.

llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp

@@ -2423,7 +2423,7 @@ static bool targetSupportsPAuthRelocation(const Triple &TT,
                                           const MCExpr *Target,
                                           const MCExpr *DSExpr) {
   // No released version of glibc supports PAuth relocations.
-  if (TT.isOSGlibc())
+  if (TT.isOSGlibc() || TT.isMusl())
     return false;
 
   // We emit PAuth constants as IRELATIVE relocations in cases where the

llvm/lib/Target/PowerPC/PPCInstrInfo.cpp

@@ -3180,7 +3180,8 @@ bool PPCInstrInfo::expandPostRAPseudo(MachineInstr &MI) const {
     return true;
   }
   case PPC::PPCLdFixedAddr: {
-    assert(Subtarget.getTargetTriple().isOSGlibc() &&
+    assert((Subtarget.getTargetTriple().isOSGlibc() ||
+            Subtarget.getTargetTriple().isMusl()) &&
            "Only targets with Glibc expected to contain PPCLdFixedAddr");
     int64_t Offset = 0;
     const unsigned Reg = Subtarget.isPPC64() ? PPC::X13 : PPC::R2;

llvm/lib/Target/X86/X86ISelDAGToDAG.cpp

@@ -1875,8 +1875,8 @@ bool X86DAGToDAGISel::matchLoadInAddress(LoadSDNode *N, X86ISelAddressMode &AM,
   // For more information see http://people.redhat.com/drepper/tls.pdf
   if (isNullConstant(Address) && AM.Segment.getNode() == nullptr &&
       !IndirectTlsSegRefs &&
-      (Subtarget->isTargetGlibc() || Subtarget->isTargetAndroid() ||
-       Subtarget->isTargetFuchsia())) {
+      (Subtarget->isTargetGlibc() || Subtarget->isTargetMusl() ||
+       Subtarget->isTargetAndroid() || Subtarget->isTargetFuchsia())) {
     if (Subtarget->isTarget64BitILP32() && !AllowSegmentRegForX32)
       return true;
     switch (N->getPointerInfo().getAddrSpace()) {

llvm/lib/Target/X86/X86ISelLoweringCall.cpp

@@ -546,8 +546,8 @@ unsigned X86TargetLowering::getAddressSpace() const {
 }
 
 static bool hasStackGuardSlotTLS(const Triple &TargetTriple) {
-  return TargetTriple.isOSGlibc() || TargetTriple.isOSFuchsia() ||
-         TargetTriple.isAndroid();
+  return TargetTriple.isOSGlibc() || TargetTriple.isMusl() ||
+         TargetTriple.isOSFuchsia() || TargetTriple.isAndroid();
 }
 
 static Constant* SegmentOffset(IRBuilderBase &IRB,

llvm/lib/Target/X86/X86Subtarget.h

@@ -293,6 +293,7 @@ class X86Subtarget final : public X86GenSubtargetInfo {
   bool isTargetKFreeBSD() const { return TargetTriple.isOSKFreeBSD(); }
   bool isTargetHurd() const { return TargetTriple.isOSHurd(); }
   bool isTargetGlibc() const { return TargetTriple.isOSGlibc(); }
+  bool isTargetMusl() const { return TargetTriple.isMusl(); }
   bool isTargetAndroid() const { return TargetTriple.isAndroid(); }
   bool isTargetMCU() const { return TargetTriple.isOSIAMCU(); }
   bool isTargetFuchsia() const { return TargetTriple.isOSFuchsia(); }