improve comments, implement a trivial single-entry cache in
SourceManager::getInstantiationLoc. With this change, every token
expanded from a macro doesn't get its own MacroID. :)
This reduces # macro IDs in carbon.h from 16805 to 9197
llvm-svn: 40108
diff --git a/clang/Basic/SourceManager.cpp b/clang/Basic/SourceManager.cpp
index 3e2623c..0994163 100644
--- a/clang/Basic/SourceManager.cpp
+++ b/clang/Basic/SourceManager.cpp
@@ -165,16 +165,35 @@
/// getInstantiationLoc - Return a new SourceLocation that encodes the fact
/// that a token from physloc PhysLoc should actually be referenced from
/// InstantiationLoc.
-SourceLocation SourceManager::getInstantiationLoc(SourceLocation VirtLoc,
+SourceLocation SourceManager::getInstantiationLoc(SourceLocation PhysLoc,
SourceLocation InstantLoc) {
// The specified source location may be a mapped location, due to a macro
// instantiation or #line directive. Strip off this information to find out
// where the characters are actually located.
- SourceLocation PhysLoc = getPhysicalLoc(VirtLoc);
+ PhysLoc = getPhysicalLoc(PhysLoc);
// Resolve InstantLoc down to a real logical location.
InstantLoc = getLogicalLoc(InstantLoc);
+
+ // If the last macro id is close to the currently requested location, try to
+ // reuse it. This implements a single-entry cache.
+ if (!MacroIDs.empty()) {
+ MacroIDInfo &LastOne = MacroIDs.back();
+ if (LastOne.getInstantiationLoc() == InstantLoc &&
+ LastOne.getPhysicalLoc().getFileID() == PhysLoc.getFileID()) {
+
+ int PhysDelta = PhysLoc.getRawFilePos() -
+ LastOne.getPhysicalLoc().getRawFilePos();
+ if (unsigned(PhysDelta) < (1 << SourceLocation::MacroPhysOffsBits))
+ return SourceLocation::getMacroLoc(MacroIDs.size()-1,
+ (unsigned)PhysDelta, 0);
+
+ }
+ }
+
+
+
// FIXME: intelligently cache macroid's.
MacroIDs.push_back(MacroIDInfo::get(InstantLoc, PhysLoc));