Driver: ArgList::getLastArg was in fact returning the first matching arg.

- <rdar://problem/6715818> clang doesn't honor gcc semantic that last
    -O optimization option wins.

llvm-svn: 67628

clang/include/clang/Driver/ArgList.h

@@ -32,6 +32,8 @@ namespace driver {
     typedef llvm::SmallVector<Arg*, 16> arglist_type;
     typedef arglist_type::iterator iterator;
     typedef arglist_type::const_iterator const_iterator;
+    typedef arglist_type::reverse_iterator reverse_iterator;
+    typedef arglist_type::const_reverse_iterator const_reverse_iterator;
 
   private:
     /// List of argument strings used by the contained Args.
@@ -64,9 +66,15 @@ namespace driver {
     iterator begin() { return Args.begin(); }
     iterator end() { return Args.end(); }
 
+    reverse_iterator rbegin() { return Args.rbegin(); }
+    reverse_iterator rend() { return Args.rend(); }
+
     const_iterator begin() const { return Args.begin(); }
     const_iterator end() const { return Args.end(); }
     
+    const_reverse_iterator rbegin() const { return Args.rbegin(); }
+    const_reverse_iterator rend() const { return Args.rend(); }
+    
     /// append - Append \arg A to the arg list, taking ownership.
     void append(Arg *A);
 

clang/lib/Driver/ArgList.cpp

@@ -34,9 +34,7 @@ void ArgList::append(Arg *A) {
 
 Arg *ArgList::getLastArg(options::ID Id, bool Claim) const {
   // FIXME: Make search efficient?
-
-  // FIXME: This needs to not require loading of the option.
-  for (const_iterator it = begin(), ie = end(); it != ie; ++it) {
+  for (const_reverse_iterator it = rbegin(), ie = rend(); it != ie; ++it) {
     if ((*it)->getOption().matches(Id)) {
       if (Claim) (*it)->claim();
       return *it;

clang/test/Driver/clang-translation.c

@@ -1,4 +1,4 @@
-// RUN: clang -ccc-host-triple i386-unknown-unknown -### -S -Os %s -o %t.s 2> %t.log
+// RUN: clang -ccc-host-triple i386-unknown-unknown -### -S -O0 -Os %s -o %t.s 2> %t.log
 // RUN: grep '"-S"' %t.log &&
 // RUN: grep '"-disable-free"' %t.log &&
 // RUN: grep '"--relocation-model" "static"' %t.log &&