[clang] Delete duplicate code in sourcemanager (#166236)

Now that the `SourceManager::getExpansionLoc` and
`SourceManager::getSpellingLoc` functions are efficient, delete
unnecessary code duplicate in `SourceManager::getDecomposedExpansionLoc`
and `SourceManager::getDecomposedSpellingLoc` methods.

Author: SergejSalnikov

clang/include/clang/Basic/SourceManager.h

@@ -1286,32 +1286,15 @@ class SourceManager : public RefCountedBase<SourceManager> {
   /// If the location is an expansion record, walk through it until we find
   /// the final location expanded.
   FileIDAndOffset getDecomposedExpansionLoc(SourceLocation Loc) const {
-    FileID FID = getFileID(Loc);
-    auto *E = getSLocEntryOrNull(FID);
-    if (!E)
-      return std::make_pair(FileID(), 0);
-
-    unsigned Offset = Loc.getOffset()-E->getOffset();
-    if (Loc.isFileID())
-      return std::make_pair(FID, Offset);
-
-    return getDecomposedExpansionLocSlowCase(E);
+    return getDecomposedLoc(getExpansionLoc(Loc));
   }
 
   /// Decompose the specified location into a raw FileID + Offset pair.
   ///
   /// If the location is an expansion record, walk through it until we find
   /// its spelling record.
   FileIDAndOffset getDecomposedSpellingLoc(SourceLocation Loc) const {
-    FileID FID = getFileID(Loc);
-    auto *E = getSLocEntryOrNull(FID);
-    if (!E)
-      return std::make_pair(FileID(), 0);
-
-    unsigned Offset = Loc.getOffset()-E->getOffset();
-    if (Loc.isFileID())
-      return std::make_pair(FID, Offset);
-    return getDecomposedSpellingLocSlowCase(E, Offset);
+    return getDecomposedLoc(getSpellingLoc(Loc));
   }
 
   /// Returns the "included/expanded in" decomposed location of the given
@@ -1979,10 +1962,6 @@ class SourceManager : public RefCountedBase<SourceManager> {
   SourceLocation getSpellingLocSlowCase(SourceLocation Loc) const;
   SourceLocation getFileLocSlowCase(SourceLocation Loc) const;
 
-  FileIDAndOffset
-  getDecomposedExpansionLocSlowCase(const SrcMgr::SLocEntry *E) const;
-  FileIDAndOffset getDecomposedSpellingLocSlowCase(const SrcMgr::SLocEntry *E,
-                                                   unsigned Offset) const;
   void computeMacroArgsCache(MacroArgsMap &MacroArgsCache, FileID FID) const;
   void associateFileChunkWithMacroArgExp(MacroArgsMap &MacroArgsCache,
                                          FileID FID,

clang/lib/Basic/SourceManager.cpp

@@ -928,41 +928,6 @@ SourceLocation SourceManager::getFileLocSlowCase(SourceLocation Loc) const {
   return Loc;
 }
 
-FileIDAndOffset SourceManager::getDecomposedExpansionLocSlowCase(
-    const SrcMgr::SLocEntry *E) const {
-  // If this is an expansion record, walk through all the expansion points.
-  FileID FID;
-  SourceLocation Loc;
-  unsigned Offset;
-  do {
-    Loc = E->getExpansion().getExpansionLocStart();
-
-    FID = getFileID(Loc);
-    E = &getSLocEntry(FID);
-    Offset = Loc.getOffset()-E->getOffset();
-  } while (!Loc.isFileID());
-
-  return std::make_pair(FID, Offset);
-}
-
-FileIDAndOffset
-SourceManager::getDecomposedSpellingLocSlowCase(const SrcMgr::SLocEntry *E,
-                                                unsigned Offset) const {
-  // If this is an expansion record, walk through all the expansion points.
-  FileID FID;
-  SourceLocation Loc;
-  do {
-    Loc = E->getExpansion().getSpellingLoc();
-    Loc = Loc.getLocWithOffset(Offset);
-
-    FID = getFileID(Loc);
-    E = &getSLocEntry(FID);
-    Offset = Loc.getOffset()-E->getOffset();
-  } while (!Loc.isFileID());
-
-  return std::make_pair(FID, Offset);
-}
-
 /// getImmediateSpellingLoc - Given a SourceLocation object, return the
 /// spelling location referenced by the ID.  This is the first level down
 /// towards the place where the characters that make up the lexed token can be