Simplify large switches.

[ruiu]

Summary

This may be a little bit inefficient than the original code
but that should be okay as this is not really in a performance
critical pass.

[rafaelauler]

LGTM

[Eugene.Zelenko]

Committed in r228077.

lib/ReaderWriter/LinkerScript.cpp

static llvm::ErrorOr<uint64_t> parseNum(StringRef str) {
   return res;
 }
 
 bool Lexer::canStartNumber(char c) const {
   return '0' <= c && c <= '9';
 }
 
 bool Lexer::canContinueNumber(char c) const {
-  switch (c) {
-  // Digits
-  case '0': case '1': case '2': case '3': case '4': case '5': case '6':
-  case '7': case '8': case '9':
-  case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
-  case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
-  // Hex marker
-  case 'x': case 'X':
-  // Type suffix
-  case 'h': case 'H': case 'o': case 'O':
-  // Scale suffix
-  case 'M': case 'K':
-    return true;
-  default:
-    return false;
-  }
+  return strchr("0123456789ABCDEFabcdefxXhHoOMK", c);
 }
 
 bool Lexer::canStartName(char c) const {
-  switch (c) {
-  case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G':
-  case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N':
-  case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U':
-  case 'V': case 'W': case 'X': case 'Y': case 'Z':
-  case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g':
-  case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
-  case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u':
-  case 'v': case 'w': case 'x': case 'y': case 'z':
-  case '_': case '.': case '$': case '/': case '\\':
-  case '*':
-    return true;
-  default:
-    return false;
-  }
+  return strchr(
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz_.$/\\*", c);
 }
 
 bool Lexer::canContinueName(char c) const {
-  switch (c) {
-  case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G':
-  case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N':
-  case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U':
-  case 'V': case 'W': case 'X': case 'Y': case 'Z':
-  case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g':
-  case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
-  case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u':
-  case 'v': case 'w': case 'x': case 'y': case 'z':
-  case '0': case '1': case '2': case '3': case '4': case '5': case '6':
-  case '7': case '8': case '9':
-  case '_': case '.': case '$': case '/': case '\\': case '~': case '=':
-  case '+':
-  case '[':
-  case ']':
-  case '*':
-  case '?':
-  case '-':
-  case ':':
-    return true;
-  default:
-    return false;
-  }
+  return strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
+                "0123456789_.$/\\~=+[]*?-:", c);
 }
 
 /// Helper function to split a StringRef in two at the nth character.
 /// The StringRef s is updated, while the function returns the n first
 /// characters.
 static StringRef drop(StringRef &s, int n) {
   StringRef res = s.substr(0, n);
   s = s.drop_front(n);