Make getLastArgNoClaim work for up to 4 arguments.

[filcab]

Summary

This is needed for http://reviews.llvm.org/D8507
I have no idea what stand-alone tests could be done, if needed.

[samsonov]

LGTM

[Bigcheese]

Why not make this a variadic template?

[probinson]

In D8508#144526, @Bigcheese wrote:

Why not make this a variadic template?

A variadic "matches" method on Option would keep it from being
amazingly inefficient. (i.e. don't iterate through ArgList N times.)

[silvas]

In D8508#144677, @probinson wrote:

In D8508#144526, @Bigcheese wrote:

Why not make this a variadic template?

A variadic "matches" method on Option would keep it from being
amazingly inefficient. (i.e. don't iterate through ArgList N times.)

The real solution is to not have to walk the list for every method call like this. I.e. use a data structure that efficiently supports these sorts of queries.

[probinson]

In D8508#145721, @silvas wrote:

In D8508#144677, @probinson wrote:

In D8508#144526, @Bigcheese wrote:

Why not make this a variadic template?

A variadic "matches" method on Option would keep it from being
amazingly inefficient. (i.e. don't iterate through ArgList N times.)

The real solution is to not have to walk the list for every method call like this. I.e. use a data structure that efficiently supports these sorts of queries.

Well, sure. I just didn't want Michael's comment to prompt an inductive template on getLastArg, which would be worse.

llvm/trunk/include/llvm/Option/ArgList.h

bool hasArg(OptSpecifier Id0, OptSpecifier Id1, OptSpecifier Id2) const {
     return getLastArg(Id0, Id1, Id2) != nullptr;
   }
 
   /// getLastArg - Return the last argument matching \p Id, or null.
   ///
   /// \p Claim Whether the argument should be claimed, if it exists.
   Arg *getLastArgNoClaim(OptSpecifier Id) const;
   Arg *getLastArgNoClaim(OptSpecifier Id0, OptSpecifier Id1) const;
+  Arg *getLastArgNoClaim(OptSpecifier Id0, OptSpecifier Id1,
+                         OptSpecifier Id2) const;
+  Arg *getLastArgNoClaim(OptSpecifier Id0, OptSpecifier Id1, OptSpecifier Id2,
+                         OptSpecifier Id3) const;
   Arg *getLastArg(OptSpecifier Id) const;
   Arg *getLastArg(OptSpecifier Id0, OptSpecifier Id1) const;
   Arg *getLastArg(OptSpecifier Id0, OptSpecifier Id1, OptSpecifier Id2) const;
   Arg *getLastArg(OptSpecifier Id0, OptSpecifier Id1, OptSpecifier Id2,
                   OptSpecifier Id3) const;
   Arg *getLastArg(OptSpecifier Id0, OptSpecifier Id1, OptSpecifier Id2,
                   OptSpecifier Id3, OptSpecifier Id4) const;
   Arg *getLastArg(OptSpecifier Id0, OptSpecifier Id1, OptSpecifier Id2,

llvm/trunk/lib/Option/ArgList.cpp

Arg *ArgList::getLastArgNoClaim(OptSpecifier Id0, OptSpecifier Id1) const {
   // FIXME: Make search efficient?
   for (const_reverse_iterator it = rbegin(), ie = rend(); it != ie; ++it)
     if ((*it)->getOption().matches(Id0) ||
         (*it)->getOption().matches(Id1))
       return *it;
   return nullptr;
 }
 
+Arg *ArgList::getLastArgNoClaim(OptSpecifier Id0, OptSpecifier Id1,
+                                OptSpecifier Id2) const {
+  // FIXME: Make search efficient?
+  for (const_reverse_iterator it = rbegin(), ie = rend(); it != ie; ++it)
+    if ((*it)->getOption().matches(Id0) || (*it)->getOption().matches(Id1) ||
+        (*it)->getOption().matches(Id2))
+      return *it;
+  return nullptr;
+}
+
+Arg *ArgList::getLastArgNoClaim(OptSpecifier Id0, OptSpecifier Id1,
+                                OptSpecifier Id2, OptSpecifier Id3) const {
+  // FIXME: Make search efficient?
+  for (const_reverse_iterator it = rbegin(), ie = rend(); it != ie; ++it)
+    if ((*it)->getOption().matches(Id0) || (*it)->getOption().matches(Id1) ||
+        (*it)->getOption().matches(Id2) || (*it)->getOption().matches(Id3))
+      return *it;
+  return nullptr;
+}
+
 Arg *ArgList::getLastArg(OptSpecifier Id) const {
   Arg *Res = nullptr;
   for (const_iterator it = begin(), ie = end(); it != ie; ++it) {
     if ((*it)->getOption().matches(Id)) {
       Res = *it;
       Res->claim();
     }
   }