[lld-link] Replace errorHandler() with ctx.e

errorHandler() uses the global state, which should be avoided in
lld/COFF code.

Author: MaskRay

lld/COFF/Driver.cpp

@@ -1582,7 +1582,7 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
     StringRef s = arg->getValue();
     if (s.getAsInteger(10, n))
       error(arg->getSpelling() + " number expected, but got " + s);
-    errorHandler().errorLimit = n;
+    ctx.e.errorLimit = n;
   }
 
   config->vfs = getVFS(args);
@@ -1696,7 +1696,7 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
   // Handle /verbose
   if (args.hasArg(OPT_verbose))
     config->verbose = true;
-  errorHandler().verbose = config->verbose;
+  ctx.e.verbose = config->verbose;
 
   // Handle /force or /force:unresolved
   if (args.hasArg(OPT_force, OPT_force_unresolved))

lld/COFF/DriverUtils.cpp

@@ -934,7 +934,7 @@ opt::InputArgList ArgParser::parse(ArrayRef<const char *> argv) {
   }
 
   // Handle /WX early since it converts missing argument warnings to errors.
-  errorHandler().fatalWarnings = args.hasFlag(OPT_WX, OPT_WX_no, false);
+  ctx.e.fatalWarnings = args.hasFlag(OPT_WX, OPT_WX_no, false);
 
   if (missingCount)
     fatal(Twine(args.getArgString(missingIndex)) + ": missing argument");

lld/COFF/Writer.cpp

@@ -205,7 +205,7 @@ struct ChunkRange {
 class Writer {
 public:
   Writer(COFFLinkerContext &c)
-      : buffer(errorHandler().outputBuffer), delayIdata(c), edata(c), ctx(c) {}
+      : buffer(c.e.outputBuffer), delayIdata(c), edata(c), ctx(c) {}
   void run();
 
 private: