make my atrocious linear search at least search in the order that is
more likely to hit.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63714 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/SourceManager.cpp b/lib/Basic/SourceManager.cpp
index c322646..d9cf5e1 100644
--- a/lib/Basic/SourceManager.cpp
+++ b/lib/Basic/SourceManager.cpp
@@ -160,14 +160,13 @@
const std::vector<LineEntry> &Entries = LineEntries[FID];
assert(!Entries.empty() && "No #line entries for this FID after all!");
- if (Entries[0].FileOffset > Offset) return 0;
// FIXME: Dumb linear search.
// Find the maximal element that is still before Offset.
- for (unsigned i = 1, e = Entries.size(); i != e; ++i)
- if (Entries[i].FileOffset > Offset) return &Entries[i-1];
- // Otherwise, all entries are before Offset.
- return &Entries.back();
+ for (std::vector<LineEntry>::const_reverse_iterator I = Entries.rbegin(),
+ E = Entries.rend(); I != E; ++I)
+ if (I->FileOffset <= Offset) return &*I;
+ return 0;
}