[llvm] Use x.empty() instead of llvm::empty(x) (NFC)

I'm planning to deprecate and eventually remove llvm::empty.

I thought about replacing llvm::empty(x) with std::empty(x), but it
turns out that all uses can be converted to x.empty().  That is, no
use requires the ability of std::empty to accept C arrays and
std::initializer_list.

Differential Revision: https://reviews.llvm.org/D133677

llvm/include/llvm/ExecutionEngine/JITLink/JITLink.h

@@ -774,7 +774,7 @@ class SectionRange {
 public:
   SectionRange() = default;
   SectionRange(const Section &Sec) {
-    if (llvm::empty(Sec.blocks()))
+    if (Sec.blocks().empty())
       return;
     First = Last = *Sec.blocks().begin();
     for (auto *B : Sec.blocks()) {

llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp

@@ -42,7 +42,7 @@ void DwarfFile::emitUnit(DwarfUnit *TheU, bool UseOffsets) {
 
   // Skip CUs that ended up not being needed (split CUs that were abandoned
   // because they added no information beyond the non-split CU)
-  if (llvm::empty(TheU->getUnitDie().values()))
+  if (TheU->getUnitDie().values().empty())
     return;
 
   Asm->OutStreamer->switchSection(S);
@@ -66,7 +66,7 @@ void DwarfFile::computeSizeAndOffsets() {
 
     // Skip CUs that ended up not being needed (split CUs that were abandoned
     // because they added no information beyond the non-split CU)
-    if (llvm::empty(TheU->getUnitDie().values()))
+    if (TheU->getUnitDie().values().empty())
       return;
 
     TheU->setDebugSectionOffset(SecOffset);

llvm/lib/ExecutionEngine/JITLink/JITLink.cpp

@@ -309,14 +309,14 @@ void LinkGraph::dump(raw_ostream &OS) {
   }
 
   OS << "Absolute symbols:\n";
-  if (!llvm::empty(absolute_symbols())) {
+  if (!absolute_symbols().empty()) {
     for (auto *Sym : absolute_symbols())
       OS << "  " << Sym->getAddress() << ": " << *Sym << "\n";
   } else
     OS << "  none\n";
 
   OS << "\nExternal symbols:\n";
-  if (!llvm::empty(external_symbols())) {
+  if (!external_symbols().empty()) {
     for (auto *Sym : external_symbols())
       OS << "  " << Sym->getAddress() << ": " << *Sym << "\n";
   } else

llvm/lib/ExecutionEngine/JITLink/JITLinkMemoryManager.cpp

@@ -25,7 +25,7 @@ BasicLayout::BasicLayout(LinkGraph &G) : G(G) {
 
   for (auto &Sec : G.sections()) {
     // Skip empty sections.
-    if (empty(Sec.blocks()))
+    if (Sec.blocks().empty())
       continue;
 
     auto &Seg = Segments[{Sec.getMemProt(), Sec.getMemDeallocPolicy()}];

llvm/lib/ExecutionEngine/Orc/DebuggerSupportPlugin.cpp

@@ -137,7 +137,7 @@ public:
     SmallVector<DebugSectionInfo, 12> DebugSecInfos;
     size_t NumSections = 0;
     for (auto &Sec : G.sections()) {
-      if (llvm::empty(Sec.blocks()))
+      if (Sec.blocks().empty())
         continue;
 
       ++NumSections;
@@ -189,7 +189,7 @@ public:
     // Copy debug section blocks and symbols.
     orc::ExecutorAddr NextBlockAddr(MachOContainerBlock->getSize());
     for (auto &SI : DebugSecInfos) {
-      assert(!llvm::empty(SI.Sec->blocks()) && "Empty debug info section?");
+      assert(!SI.Sec->blocks().empty() && "Empty debug info section?");
 
       // Update addresses in debug section.
       LLVM_DEBUG({

llvm/lib/ExecutionEngine/Orc/Layer.cpp

@@ -81,7 +81,7 @@ IRMaterializationUnit::IRMaterializationUnit(
     }
 
     // If we need an init symbol for this module then create one.
-    if (!llvm::empty(getStaticInitGVs(M))) {
+    if (!getStaticInitGVs(M).empty()) {
       size_t Counter = 0;
 
       do {

llvm/lib/ExecutionEngine/Orc/MachOPlatform.cpp

@@ -744,7 +744,7 @@ Error MachOPlatform::MachOPlatformPlugin::processObjCImageInfo(
   auto ObjCImageInfoBlocks = ObjCImageInfo->blocks();
 
   // Check that the section is not empty if present.
-  if (llvm::empty(ObjCImageInfoBlocks))
+  if (ObjCImageInfoBlocks.empty())
     return make_error<StringError>("Empty " + ObjCImageInfoSectionName +
                                        " section in " + G.getName(),
                                    inconvertibleErrorCode());

llvm/lib/Target/AMDGPU/AMDGPURegisterBankInfo.cpp

@@ -2539,7 +2539,7 @@ void AMDGPURegisterBankInfo::applyMappingImpl(
     LLT SrcTy = MRI.getType(SrcReg);
     const bool Signed = Opc == AMDGPU::G_SEXT;
 
-    assert(empty(OpdMapper.getVRegs(1)));
+    assert(OpdMapper.getVRegs(1).empty());
 
     MachineIRBuilder B(MI);
     const RegisterBank *SrcBank =

llvm/lib/Target/X86/X86FastISel.cpp

@@ -274,9 +274,7 @@ bool X86FastISel::foldX86XALUIntrinsic(X86::CondCode &CC, const Instruction *I,
 
   // Make sure no potentially eflags clobbering phi moves can be inserted in
   // between.
-  auto HasPhis = [](const BasicBlock *Succ) {
+  auto HasPhis = [](const BasicBlock *Succ) { return !Succ->phis().empty(); };
-    return !llvm::empty(Succ->phis());
-  };
   if (I->isTerminator() && llvm::any_of(successors(I), HasPhis))
     return false;
 

llvm/lib/Transforms/Utils/LoopUtils.cpp

@@ -1843,7 +1843,7 @@ Optional<IVConditionInfo> llvm::hasPartialIVCondition(Loop &L,
           if (L.contains(Succ))
             continue;
 
-          Info.PathIsNoop &= llvm::empty(Succ->phis()) &&
+          Info.PathIsNoop &= Succ->phis().empty() &&
                              (!Info.ExitForPath || Info.ExitForPath == Succ);
           if (!Info.PathIsNoop)
             break;

llvm/tools/llvm-jitlink/llvm-jitlink-coff.cpp

@@ -80,13 +80,12 @@ Error registerCOFFGraphInfo(Session &S, LinkGraph &G) {
   for (auto &Sec : G.sections()) {
     LLVM_DEBUG({
       dbgs() << "  Section \"" << Sec.getName() << "\": "
-             << (llvm::empty(Sec.symbols()) ? "empty. skipping."
+             << (Sec.symbols().empty() ? "empty. skipping." : "processing...")
-                                            : "processing...")
              << "\n";
     });
 
     // Skip empty sections.
-    if (llvm::empty(Sec.symbols()))
+    if (Sec.symbols().empty())
       continue;
 
     if (FileInfo.SectionInfos.count(Sec.getName()))

llvm/tools/llvm-jitlink/llvm-jitlink-elf.cpp

@@ -82,13 +82,12 @@ Error registerELFGraphInfo(Session &S, LinkGraph &G) {
   for (auto &Sec : G.sections()) {
     LLVM_DEBUG({
       dbgs() << "  Section \"" << Sec.getName() << "\": "
-             << (llvm::empty(Sec.symbols()) ? "empty. skipping."
+             << (Sec.symbols().empty() ? "empty. skipping." : "processing...")
-                                            : "processing...")
              << "\n";
     });
 
     // Skip empty sections.
-    if (llvm::empty(Sec.symbols()))
+    if (Sec.symbols().empty())
       continue;
 
     if (FileInfo.SectionInfos.count(Sec.getName()))

llvm/tools/llvm-jitlink/llvm-jitlink-macho.cpp

@@ -84,13 +84,12 @@ Error registerMachOGraphInfo(Session &S, LinkGraph &G) {
   for (auto &Sec : G.sections()) {
     LLVM_DEBUG({
       dbgs() << "  Section \"" << Sec.getName() << "\": "
-             << (llvm::empty(Sec.symbols()) ? "empty. skipping."
+             << (Sec.symbols().empty() ? "empty. skipping." : "processing...")
-                                            : "processing...")
              << "\n";
     });
 
     // Skip empty sections.
-    if (llvm::empty(Sec.symbols()))
+    if (Sec.symbols().empty())
       continue;
 
     if (FileInfo.SectionInfos.count(Sec.getName()))

llvm/tools/llvm-jitlink/llvm-jitlink.cpp

@@ -403,11 +403,11 @@ static void dumpSectionContents(raw_ostream &OS, LinkGraph &G) {
     Sections.push_back(&S);
 
   llvm::sort(Sections, [](const Section *LHS, const Section *RHS) {
-    if (llvm::empty(LHS->symbols()) && llvm::empty(RHS->symbols()))
+    if (LHS->symbols().empty() && RHS->symbols().empty())
       return false;
-    if (llvm::empty(LHS->symbols()))
+    if (LHS->symbols().empty())
       return false;
-    if (llvm::empty(RHS->symbols()))
+    if (RHS->symbols().empty())
       return true;
     SectionRange LHSRange(*LHS);
     SectionRange RHSRange(*RHS);
@@ -416,7 +416,7 @@ static void dumpSectionContents(raw_ostream &OS, LinkGraph &G) {
 
   for (auto *S : Sections) {
     OS << S->getName() << " content:";
-    if (llvm::empty(S->symbols())) {
+    if (S->symbols().empty()) {
       OS << "\n  section empty\n";
       continue;
     }