diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -57,10 +57,15 @@
 namespace lld {
 namespace coff {
 
+static void initGlobals();
 static Timer inputFileTimer("Input File Reading", Timer::root());
 
+// If you add a new global variable, make sure that you add initialization code
+// to initGlobals() too.
 Configuration *config;
 LinkerDriver *driver;
+SymbolTable *symtab;
+std::vector<OutputSection *> outputSections;
 
 bool link(ArrayRef<const char *> args, bool canExitEarly, raw_ostream &stdoutOS,
           raw_ostream &stderrOS) {
@@ -74,6 +79,8 @@
   errorHandler().exitEarly = canExitEarly;
   stderrOS.enable_colors(stderrOS.has_colors());
 
+  initGlobals();
+
   config = make<Configuration>();
   symtab = make<SymbolTable>();
   driver = make<LinkerDriver>();
@@ -92,6 +99,16 @@
   return !errorCount();
 }
 
+// Reset globals. We want to make sure that on every linker invocation, we start
+// with fresh global variables, so that users who link lld as a library can call
+// link() multiple times from the same process.
+static void initGlobals() {
+  config = nullptr;
+  driver = nullptr;
+  symtab = nullptr;
+  outputSections.clear();
+}
+
 // Parse options of the form "old;new".
 static std::pair<StringRef, StringRef> getOldNewOptions(opt::InputArgList &args,
                                                         unsigned id) {
diff --git a/lld/COFF/SymbolTable.cpp b/lld/COFF/SymbolTable.cpp
--- a/lld/COFF/SymbolTable.cpp
+++ b/lld/COFF/SymbolTable.cpp
@@ -30,8 +30,6 @@
 
 static Timer ltoTimer("LTO", Timer::root());
 
-SymbolTable *symtab;
-
 void SymbolTable::addFile(InputFile *file) {
   log("Reading " + toString(file));
   file->parse();
diff --git a/lld/COFF/Writer.h b/lld/COFF/Writer.h
--- a/lld/COFF/Writer.h
+++ b/lld/COFF/Writer.h
@@ -18,6 +18,11 @@
 
 namespace lld {
 namespace coff {
+
+class OutputSection;
+
+extern std::vector<OutputSection *> outputSections;
+
 static const int pageSize = 4096;
 
 void writeResult();
diff --git a/lld/COFF/Writer.cpp b/lld/COFF/Writer.cpp
--- a/lld/COFF/Writer.cpp
+++ b/lld/COFF/Writer.cpp
@@ -80,10 +80,6 @@
 
 static const int numberOfDataDirectory = 16;
 
-// Global vector of all output sections. After output sections are finalized,
-// this can be indexed by Chunk::getOutputSection.
-static std::vector<OutputSection *> outputSections;
-
 OutputSection *Chunk::getOutputSection() const {
   return osidx == 0 ? nullptr : outputSections[osidx - 1];
 }
diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -69,9 +69,26 @@
 namespace lld {
 namespace elf {
 
+// If you add a new global variable, make sure that you add initialization code
+// to initGlobals() too.
 Configuration *config;
+InStruct in;
 LinkerDriver *driver;
-
+LinkerScript *script;
+Partition *mainPart;
+SymbolTable *symtab;
+const TargetInfo *target;
+std::unique_ptr<llvm::TarWriter> tar;
+std::vector<BinaryFile *> binaryFiles;
+std::vector<BitcodeFile *> bitcodeFiles;
+std::vector<InputFile *> objectFiles;
+std::vector<InputSectionBase *> inputSections;
+std::vector<LazyObjFile *> lazyObjFiles;
+std::vector<OutputSection *> outputSections;
+std::vector<Partition> partitions;
+std::vector<SharedFile *> sharedFiles;
+
+static void initGlobals();
 static void setConfigs(opt::InputArgList &args);
 static void readConfigs(opt::InputArgList &args);
 
@@ -87,12 +104,7 @@
   errorHandler().exitEarly = canExitEarly;
   stderrOS.enable_colors(stderrOS.has_colors());
 
-  inputSections.clear();
-  outputSections.clear();
-  binaryFiles.clear();
-  bitcodeFiles.clear();
-  objectFiles.clear();
-  sharedFiles.clear();
+  initGlobals();
 
   config = make<Configuration>();
   driver = make<LinkerDriver>();
@@ -120,6 +132,28 @@
   return !errorCount();
 }
 
+// Reset globals. We want to make sure that on every linker invocation, we start
+// with fresh global variables, so that users who link lld as a library can call
+// link() multiple times from the same process.
+static void initGlobals() {
+  config = nullptr;
+  memset(&in, 0, sizeof(in));
+  driver = nullptr;
+  script = nullptr;
+  mainPart = nullptr;
+  symtab = nullptr;
+  target = nullptr;
+  tar.reset();
+  binaryFiles.clear();
+  bitcodeFiles.clear();
+  objectFiles.clear();
+  inputSections.clear();
+  lazyObjFiles.clear();
+  outputSections.clear();
+  partitions.clear();
+  sharedFiles.clear();
+}
+
 // Parses a linker -m option.
 static std::tuple<ELFKind, uint16_t, uint8_t> parseEmulation(StringRef emul) {
   uint8_t osabi = 0;
diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp
--- a/lld/ELF/InputFiles.cpp
+++ b/lld/ELF/InputFiles.cpp
@@ -55,13 +55,6 @@
 namespace elf {
 bool InputFile::isInGroup;
 uint32_t InputFile::nextGroupId;
-std::vector<BinaryFile *> binaryFiles;
-std::vector<BitcodeFile *> bitcodeFiles;
-std::vector<LazyObjFile *> lazyObjFiles;
-std::vector<InputFile *> objectFiles;
-std::vector<SharedFile *> sharedFiles;
-
-std::unique_ptr<TarWriter> tar;
 
 static ELFKind getELFKind(MemoryBufferRef mb, StringRef archiveName) {
   unsigned char size;
diff --git a/lld/ELF/InputSection.cpp b/lld/ELF/InputSection.cpp
--- a/lld/ELF/InputSection.cpp
+++ b/lld/ELF/InputSection.cpp
@@ -44,7 +44,6 @@
 }
 
 namespace elf {
-std::vector<InputSectionBase *> inputSections;
 
 template <class ELFT>
 static ArrayRef<uint8_t> getSectionContents(ObjFile<ELFT> &file,
diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -46,7 +46,6 @@
 
 namespace lld {
 namespace elf {
-LinkerScript *script;
 
 static uint64_t getOutputSectionVA(SectionBase *sec) {
   OutputSection *os = sec->getOutputSection();
diff --git a/lld/ELF/OutputSections.cpp b/lld/ELF/OutputSections.cpp
--- a/lld/ELF/OutputSections.cpp
+++ b/lld/ELF/OutputSections.cpp
@@ -39,8 +39,6 @@
 OutputSection *Out::initArray;
 OutputSection *Out::finiArray;
 
-std::vector<OutputSection *> outputSections;
-
 uint32_t OutputSection::getPhdrFlags() const {
   uint32_t ret = 0;
   if (config->emachine != EM_ARM || !(flags & SHF_ARM_PURECODE))
diff --git a/lld/ELF/SymbolTable.cpp b/lld/ELF/SymbolTable.cpp
--- a/lld/ELF/SymbolTable.cpp
+++ b/lld/ELF/SymbolTable.cpp
@@ -29,7 +29,6 @@
 
 namespace lld {
 namespace elf {
-SymbolTable *symtab;
 
 void SymbolTable::wrap(Symbol *sym, Symbol *real, Symbol *wrap) {
   // Swap symbols as instructed by -wrap.
diff --git a/lld/ELF/SyntheticSections.cpp b/lld/ELF/SyntheticSections.cpp
--- a/lld/ELF/SyntheticSections.cpp
+++ b/lld/ELF/SyntheticSections.cpp
@@ -3584,11 +3584,6 @@
   }
 }
 
-InStruct in;
-
-std::vector<Partition> partitions;
-Partition *mainPart;
-
 template GdbIndexSection *GdbIndexSection::create<ELF32LE>();
 template GdbIndexSection *GdbIndexSection::create<ELF32BE>();
 template GdbIndexSection *GdbIndexSection::create<ELF64LE>();
diff --git a/lld/ELF/Target.cpp b/lld/ELF/Target.cpp
--- a/lld/ELF/Target.cpp
+++ b/lld/ELF/Target.cpp
@@ -44,7 +44,6 @@
 }
 
 namespace elf {
-const TargetInfo *target;
 
 TargetInfo *getTarget() {
   switch (config->emachine) {