[ELF] Remove ctx indirection. NFC

Add LLVM_LIBRARY_VISIBILITY to remove unneeded GOT and unique_ptr
indirection. We can move other global variables into ctx without
indirection concern. In the long term we may consider passing Ctx
as a parameter to various functions and eliminate global state as
much as possible and then remove `Ctx::reset`.

lld/ELF/AArch64ErrataFix.cpp

@@ -439,7 +439,7 @@ void AArch64Err843419Patcher::init() {
   };
 
   // Collect mapping symbols for every executable InputSection.
-  for (ELFFileBase *file : ctx->objectFiles) {
+  for (ELFFileBase *file : ctx.objectFiles) {
     for (Symbol *b : file->getLocalSymbols()) {
       auto *def = dyn_cast<Defined>(b);
       if (!def)

lld/ELF/ARMErrataFix.cpp

@@ -327,7 +327,7 @@ void ARMErr657417Patcher::init() {
   };
 
   // Collect mapping symbols for every executable InputSection.
-  for (ELFFileBase *file : ctx->objectFiles) {
+  for (ELFFileBase *file : ctx.objectFiles) {
     for (Symbol *s : file->getLocalSymbols()) {
       auto *def = dyn_cast<Defined>(s);
       if (!def)

lld/ELF/Arch/AMDGPU.cpp

@@ -48,10 +48,10 @@ static uint32_t getEFlags(InputFile *file) {
 }
 
 uint32_t AMDGPU::calcEFlagsV3() const {
-  uint32_t ret = getEFlags(ctx->objectFiles[0]);
+  uint32_t ret = getEFlags(ctx.objectFiles[0]);
 
   // Verify that all input files have the same e_flags.
-  for (InputFile *f : makeArrayRef(ctx->objectFiles).slice(1)) {
+  for (InputFile *f : makeArrayRef(ctx.objectFiles).slice(1)) {
     if (ret == getEFlags(f))
       continue;
     error("incompatible e_flags: " + toString(f));
@@ -61,15 +61,15 @@ uint32_t AMDGPU::calcEFlagsV3() const {
 }
 
 uint32_t AMDGPU::calcEFlagsV4() const {
-  uint32_t retMach = getEFlags(ctx->objectFiles[0]) & EF_AMDGPU_MACH;
+  uint32_t retMach = getEFlags(ctx.objectFiles[0]) & EF_AMDGPU_MACH;
   uint32_t retXnack =
-      getEFlags(ctx->objectFiles[0]) & EF_AMDGPU_FEATURE_XNACK_V4;
+      getEFlags(ctx.objectFiles[0]) & EF_AMDGPU_FEATURE_XNACK_V4;
   uint32_t retSramEcc =
-      getEFlags(ctx->objectFiles[0]) & EF_AMDGPU_FEATURE_SRAMECC_V4;
+      getEFlags(ctx.objectFiles[0]) & EF_AMDGPU_FEATURE_SRAMECC_V4;
 
   // Verify that all input files have compatible e_flags (same mach, all
   // features in the same category are either ANY, ANY and ON, or ANY and OFF).
-  for (InputFile *f : makeArrayRef(ctx->objectFiles).slice(1)) {
+  for (InputFile *f : makeArrayRef(ctx.objectFiles).slice(1)) {
     if (retMach != (getEFlags(f) & EF_AMDGPU_MACH)) {
       error("incompatible mach: " + toString(f));
       return 0;
@@ -106,10 +106,10 @@ uint32_t AMDGPU::calcEFlagsV4() const {
 }
 
 uint32_t AMDGPU::calcEFlags() const {
-  if (ctx->objectFiles.empty())
+  if (ctx.objectFiles.empty())
     return 0;
 
-  uint8_t abiVersion = cast<ObjFile<ELF64LE>>(ctx->objectFiles[0])
+  uint8_t abiVersion = cast<ObjFile<ELF64LE>>(ctx.objectFiles[0])
                            ->getObj()
                            .getHeader()
                            .e_ident[EI_ABIVERSION];

lld/ELF/Arch/AVR.cpp

@@ -226,12 +226,12 @@ static uint32_t getEFlags(InputFile *file) {
 }
 
 uint32_t AVR::calcEFlags() const {
-  assert(!ctx->objectFiles.empty());
+  assert(!ctx.objectFiles.empty());
 
-  uint32_t flags = getEFlags(ctx->objectFiles[0]);
+  uint32_t flags = getEFlags(ctx.objectFiles[0]);
   bool hasLinkRelaxFlag = flags & EF_AVR_LINKRELAX_PREPARED;
 
-  for (InputFile *f : makeArrayRef(ctx->objectFiles).slice(1)) {
+  for (InputFile *f : makeArrayRef(ctx.objectFiles).slice(1)) {
     uint32_t objFlags = getEFlags(f);
     if ((objFlags & EF_AVR_ARCH_MASK) != (flags & EF_AVR_ARCH_MASK))
       error(toString(f) +

lld/ELF/Arch/Hexagon.cpp

@@ -59,12 +59,12 @@ Hexagon::Hexagon() {
 }
 
 uint32_t Hexagon::calcEFlags() const {
-  assert(!ctx->objectFiles.empty());
+  assert(!ctx.objectFiles.empty());
 
   // The architecture revision must always be equal to or greater than
   // greatest revision in the list of inputs.
   uint32_t ret = 0;
-  for (InputFile *f : ctx->objectFiles) {
+  for (InputFile *f : ctx.objectFiles) {
     uint32_t eflags = cast<ObjFile<ELF32LE>>(f)->getObj().getHeader().e_flags;
     if (eflags > ret)
       ret = eflags;

lld/ELF/Arch/MipsArchTree.cpp

@@ -295,7 +295,7 @@ static uint32_t getArchFlags(ArrayRef<FileFlags> files) {
 
 template <class ELFT> uint32_t elf::calcMipsEFlags() {
   std::vector<FileFlags> v;
-  for (InputFile *f : ctx->objectFiles)
+  for (InputFile *f : ctx.objectFiles)
     v.push_back({f, cast<ObjFile<ELFT>>(f)->getObj().getHeader().e_flags});
   if (v.empty()) {
     // If we don't have any input files, we'll have to rely on the information

lld/ELF/Arch/PPC64.cpp

@@ -622,7 +622,7 @@ static uint32_t getEFlags(InputFile *file) {
 // This file implements v2 ABI. This function makes sure that all
 // object files have v2 or an unspecified version as an ABI version.
 uint32_t PPC64::calcEFlags() const {
-  for (InputFile *f : ctx->objectFiles) {
+  for (InputFile *f : ctx.objectFiles) {
     uint32_t flag = getEFlags(f);
     if (flag == 1)
       error(toString(f) + ": ABI version 1 is not supported");

lld/ELF/Arch/RISCV.cpp

@@ -128,12 +128,12 @@ static uint32_t getEFlags(InputFile *f) {
 uint32_t RISCV::calcEFlags() const {
   // If there are only binary input files (from -b binary), use a
   // value of 0 for the ELF header flags.
-  if (ctx->objectFiles.empty())
+  if (ctx.objectFiles.empty())
     return 0;
 
-  uint32_t target = getEFlags(ctx->objectFiles.front());
+  uint32_t target = getEFlags(ctx.objectFiles.front());
 
-  for (InputFile *f : ctx->objectFiles) {
+  for (InputFile *f : ctx.objectFiles) {
     uint32_t eflags = getEFlags(f);
     if (eflags & EF_RISCV_RVC)
       target |= EF_RISCV_RVC;
@@ -142,7 +142,7 @@ uint32_t RISCV::calcEFlags() const {
       error(
           toString(f) +
           ": cannot link object files with different floating-point ABI from " +
-          toString(ctx->objectFiles[0]));
+          toString(ctx.objectFiles[0]));
 
     if ((eflags & EF_RISCV_RVE) != (target & EF_RISCV_RVE))
       error(toString(f) +
@@ -524,7 +524,7 @@ static void initSymbolAnchors() {
   }
   // Store anchors (st_value and st_value+st_size) for symbols relative to text
   // sections.
-  for (InputFile *file : ctx->objectFiles)
+  for (InputFile *file : ctx.objectFiles)
     for (Symbol *sym : file->getSymbols()) {
       auto *d = dyn_cast<Defined>(sym);
       if (!d || d->file != file)

lld/ELF/Config.h

@@ -395,10 +395,6 @@ struct Ctx {
   // Symbols in a non-prevailing COMDAT group which should be changed to an
   // Undefined.
   SmallVector<std::pair<Symbol *, unsigned>, 0> nonPrevailingSyms;
-  // True if SHT_LLVM_SYMPART is used.
-  std::atomic<bool> hasSympart{false};
-  // True if we need to reserve two .got entries for local-dynamic TLS model.
-  std::atomic<bool> needsTlsLd{false};
   // A tuple of (reference, extractedFile, sym). Used by --why-extract=.
   SmallVector<std::tuple<std::string, const InputFile *, const Symbol &>, 0>
       whyExtractRecords;
@@ -407,10 +403,15 @@ struct Ctx {
   llvm::DenseMap<const Symbol *,
                  std::pair<const InputFile *, const InputFile *>>
       backwardReferences;
+  // True if SHT_LLVM_SYMPART is used.
+  std::atomic<bool> hasSympart{false};
+  // True if we need to reserve two .got entries for local-dynamic TLS model.
+  std::atomic<bool> needsTlsLd{false};
+
+  void reset();
 };
 
-// The only instance of Ctx struct.
-extern std::unique_ptr<Ctx> ctx;
+LLVM_LIBRARY_VISIBILITY extern Ctx ctx;
 
 // The first two elements of versionDefinitions represent VER_NDX_LOCAL and
 // VER_NDX_GLOBAL. This helper returns other elements.