Remove potentially N^2 algorithm from symbol table reader. No speedup
in practice though
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8985 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Bytecode/Reader/Reader.cpp b/lib/Bytecode/Reader/Reader.cpp
index e649cdc..c515c15 100644
--- a/lib/Bytecode/Reader/Reader.cpp
+++ b/lib/Bytecode/Reader/Reader.cpp
@@ -219,6 +219,9 @@
BCR_TRACE(3, "Plane Type: '" << *Ty << "' with " << NumEntries <<
" entries\n");
+ Function::iterator BlockIterator;
+ unsigned CurBlockIteratorIdx = ~0;
+
for (unsigned i = 0; i < NumEntries; ++i) {
// Symtab entry: [def slot #][name]
unsigned slot;
@@ -231,12 +234,17 @@
if (Typ == Type::TypeTyID)
V = (Value*)getType(slot);
else if (Typ == Type::LabelTyID) {
- if (CurrentFunction) {
- // FIXME: THIS IS N^2!!!
- Function::iterator BlockIterator = CurrentFunction->begin();
- std::advance(BlockIterator, slot);
- V = BlockIterator;
+ if (!CurrentFunction)
+ throw std::string("Basic blocks don't exist at global scope!");
+
+ if (slot < CurBlockIteratorIdx) {
+ CurBlockIteratorIdx = 0;
+ BlockIterator = CurrentFunction->begin();
}
+
+ std::advance(BlockIterator, slot-CurBlockIteratorIdx);
+ CurBlockIteratorIdx = slot;
+ V = BlockIterator;
} else
V = getValue(Typ, slot, false); // Find mapping...
if (V == 0) throw std::string("Failed value look-up.");