[ELF] Make Config config part of Ctx ctx

Author: MaskRay

lld/ELF/Config.h

@@ -484,12 +484,6 @@ struct Config {
   llvm::SmallVector<std::pair<llvm::GlobPattern, llvm::StringRef>, 0>
       remapInputsWildcards;
 };
-struct ConfigWrapper {
-  Config c;
-  Config *operator->() { return &c; }
-};
-
-LLVM_LIBRARY_VISIBILITY extern ConfigWrapper config;
 
 // Some index properties of a symbol are stored separately in this auxiliary
 // struct to decrease sizeof(SymbolUnion) in the majority of cases.
@@ -544,7 +538,7 @@ struct InStruct {
 };
 
 struct Ctx {
-  Config &arg;
+  Config arg;
   LinkerDriver driver;
   LinkerScript *script;
   TargetInfo *target;

lld/ELF/Driver.cpp

@@ -78,7 +78,6 @@ using namespace llvm::support;
 using namespace lld;
 using namespace lld::elf;
 
-ConfigWrapper elf::config;
 Ctx elf::ctx;
 
 static void setConfigs(Ctx &ctx, opt::InputArgList &args);
@@ -91,9 +90,11 @@ void elf::errorOrWarn(const Twine &msg) {
     error(msg);
 }
 
-Ctx::Ctx() : arg(config.c), driver(*this) {}
+Ctx::Ctx() : driver(*this) {}
 
 void Ctx::reset() {
+  arg.~Config();
+  new (&arg) Config();
   driver.~LinkerDriver();
   new (&driver) LinkerDriver(*this);
   script = nullptr;
@@ -163,8 +164,6 @@ bool link(ArrayRef<const char *> args, llvm::raw_ostream &stdoutOS,
       "too many errors emitted, stopping now (use "
       "--error-limit=0 to see all errors)";
 
-  config = ConfigWrapper();
-
   LinkerScript script(ctx);
   ctx.script = &script;
   ctx.symAux.emplace_back();