[ELF] Use SmallVector for some global variables (*Files and *Sections). NFC

My lld executable is 26+KiB smaller.

lld/ELF/InputFiles.cpp

@@ -43,12 +43,12 @@ using namespace lld::elf;
 bool InputFile::isInGroup;
 uint32_t InputFile::nextGroupId;
 
-std::vector<ArchiveFile *> elf::archiveFiles;
-std::vector<BinaryFile *> elf::binaryFiles;
-std::vector<BitcodeFile *> elf::bitcodeFiles;
-std::vector<BitcodeFile *> elf::lazyBitcodeFiles;
-std::vector<ELFFileBase *> elf::objectFiles;
-std::vector<SharedFile *> elf::sharedFiles;
+SmallVector<ArchiveFile *, 0> elf::archiveFiles;
+SmallVector<BinaryFile *, 0> elf::binaryFiles;
+SmallVector<BitcodeFile *, 0> elf::bitcodeFiles;
+SmallVector<BitcodeFile *, 0> elf::lazyBitcodeFiles;
+SmallVector<ELFFileBase *, 0> elf::objectFiles;
+SmallVector<SharedFile *, 0> elf::sharedFiles;
 
 std::unique_ptr<TarWriter> elf::tar;
 

lld/ELF/InputFiles.h

@@ -396,12 +396,12 @@ inline bool isBitcode(MemoryBufferRef mb) {
 
 std::string replaceThinLTOSuffix(StringRef path);
 
-extern std::vector<ArchiveFile *> archiveFiles;
-extern std::vector<BinaryFile *> binaryFiles;
-extern std::vector<BitcodeFile *> bitcodeFiles;
-extern std::vector<BitcodeFile *> lazyBitcodeFiles;
-extern std::vector<ELFFileBase *> objectFiles;
-extern std::vector<SharedFile *> sharedFiles;
+extern SmallVector<ArchiveFile *, 0> archiveFiles;
+extern SmallVector<BinaryFile *, 0> binaryFiles;
+extern SmallVector<BitcodeFile *, 0> bitcodeFiles;
+extern SmallVector<BitcodeFile *, 0> lazyBitcodeFiles;
+extern SmallVector<ELFFileBase *, 0> objectFiles;
+extern SmallVector<SharedFile *, 0> sharedFiles;
 
 } // namespace elf
 } // namespace lld

lld/ELF/InputSection.cpp

@@ -40,7 +40,7 @@ using namespace llvm::sys;
 using namespace lld;
 using namespace lld::elf;
 
-std::vector<InputSectionBase *> elf::inputSections;
+SmallVector<InputSectionBase *, 0> elf::inputSections;
 DenseSet<std::pair<const Symbol *, uint64_t>> elf::ppc64noTocRelax;
 
 // Returns a string to construct an error message.

lld/ELF/InputSection.h

@@ -394,7 +394,7 @@ inline bool isDebugSection(const InputSectionBase &sec) {
 }
 
 // The list of all input sections.
-extern std::vector<InputSectionBase *> inputSections;
+extern SmallVector<InputSectionBase *, 0> inputSections;
 
 // The set of TOC entries (.toc + addend) for which we should not apply
 // toc-indirect to toc-relative relaxation. const Symbol * refers to the

lld/ELF/OutputSections.cpp

@@ -40,7 +40,7 @@ OutputSection *Out::preinitArray;
 OutputSection *Out::initArray;
 OutputSection *Out::finiArray;
 
-std::vector<OutputSection *> elf::outputSections;
+SmallVector<OutputSection *, 0> elf::outputSections;
 
 uint32_t OutputSection::getPhdrFlags() const {
   uint32_t ret = 0;

lld/ELF/OutputSections.h

@@ -138,7 +138,7 @@ struct Out {
 
 uint64_t getHeaderSize();
 
-extern std::vector<OutputSection *> outputSections;
+extern llvm::SmallVector<OutputSection *, 0> outputSections;
 } // namespace elf
 } // namespace lld
 

lld/ELF/Writer.cpp

@@ -1246,7 +1246,7 @@ static void maybeShuffle(DenseMap<const InputSectionBase *, int> &order) {
   if (config->shuffleSections.empty())
     return;
 
-  std::vector<InputSectionBase *> matched, sections = inputSections;
+  SmallVector<InputSectionBase *, 0> matched, sections = inputSections;
   matched.reserve(sections.size());
   for (const auto &patAndSeed : config->shuffleSections) {
     matched.clear();