[libclang] When getting a source location from a file:line:col triplet
check whether the requested location points inside the precompiled preamble,
in which case the returned source location will be a "loaded" one.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140060 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/SourceManager.cpp b/lib/Basic/SourceManager.cpp
index 38cc994..68c98fe 100644
--- a/lib/Basic/SourceManager.cpp
+++ b/lib/Basic/SourceManager.cpp
@@ -1324,7 +1324,8 @@
 /// If the source file is included multiple times, the source location will
 /// be based upon an arbitrary inclusion.
 SourceLocation SourceManager::translateFileLineCol(const FileEntry *SourceFile,
-                                                  unsigned Line, unsigned Col) {
+                                                  unsigned Line,
+                                                  unsigned Col) const {
   assert(SourceFile && "Null source file!");
   assert(Line && Col && "Line and column should start from 1!");
 
@@ -1439,7 +1440,8 @@
 /// \brief Get the source location in \arg FID for the given line:col.
 /// Returns null location if \arg FID is not a file SLocEntry.
 SourceLocation SourceManager::translateLineCol(FileID FID,
-                                               unsigned Line, unsigned Col) {
+                                               unsigned Line,
+                                               unsigned Col) const {
   if (FID.isInvalid())
     return SourceLocation();
 
@@ -1496,7 +1498,8 @@
 ///     0   -> SourceLocation()
 ///     100 -> Expanded macro arg location
 ///     110 -> SourceLocation()
-void SourceManager::computeMacroArgsCache(ContentCache *Content, FileID FID) {
+void SourceManager::computeMacroArgsCache(ContentCache *Content,
+                                          FileID FID) const {
   assert(!Content->MacroArgsCache);
   assert(!FID.isInvalid());
 
@@ -1575,7 +1578,8 @@
 ///             ^
 /// Passing a file location pointing at 'foo', will yield a macro location
 /// where 'foo' was expanded into.
-SourceLocation SourceManager::getMacroArgExpandedLocation(SourceLocation Loc) {
+SourceLocation
+SourceManager::getMacroArgExpandedLocation(SourceLocation Loc) const {
   if (Loc.isInvalid() || !Loc.isFileID())
     return Loc;
 
diff --git a/lib/Frontend/ASTUnit.cpp b/lib/Frontend/ASTUnit.cpp
index 6f9b437..53e0412 100644
--- a/lib/Frontend/ASTUnit.cpp
+++ b/lib/Frontend/ASTUnit.cpp
@@ -1200,7 +1200,7 @@
     if (Preamble.size() == NewPreamble.second.first &&
         PreambleEndsAtStartOfLine == NewPreamble.second.second &&
         NewPreamble.first->getBufferSize() < PreambleReservedSize-2 &&
-        memcmp(&Preamble[0], NewPreamble.first->getBufferStart(),
+        memcmp(Preamble.getBufferStart(), NewPreamble.first->getBufferStart(),
                NewPreamble.second.first) == 0) {
       // The preamble has not changed. We may be able to re-use the precompiled
       // preamble.
@@ -1332,7 +1332,9 @@
 
   // Save the preamble text for later; we'll need to compare against it for
   // subsequent reparses.
-  Preamble.assign(NewPreamble.first->getBufferStart(), 
+  StringRef MainFilename = PreambleInvocation->getFrontendOpts().Inputs[0].second;
+  Preamble.assign(FileMgr->getFile(MainFilename),
+                  NewPreamble.first->getBufferStart(), 
                   NewPreamble.first->getBufferStart() 
                                                   + NewPreamble.second.first);
   PreambleEndsAtStartOfLine = NewPreamble.second.second;
@@ -2396,3 +2398,41 @@
   }
   Result.swap(Out);
 }
+
+SourceLocation ASTUnit::getLocation(const FileEntry *File,
+                                    unsigned Line, unsigned Col) const {
+  const SourceManager &SM = getSourceManager();
+  SourceLocation Loc;
+  if (!Preamble.empty() && Line <= Preamble.getNumLines())
+    Loc = SM.translateLineCol(SM.getPreambleFileID(), Line, Col);
+  else
+    Loc = SM.translateFileLineCol(File, Line, Col);
+
+  return SM.getMacroArgExpandedLocation(Loc);
+}
+
+SourceLocation ASTUnit::getLocation(const FileEntry *File,
+                                    unsigned Offset) const {
+  const SourceManager &SM = getSourceManager();
+  SourceLocation FileLoc;
+  if (!Preamble.empty() && Offset < Preamble.size())
+    FileLoc = SM.getLocForStartOfFile(SM.getPreambleFileID());
+  else
+    FileLoc = SM.translateFileLineCol(File, 1, 1);
+
+  return SM.getMacroArgExpandedLocation(FileLoc.getLocWithOffset(Offset));
+}
+
+void ASTUnit::PreambleData::countLines() const {
+  NumLines = 0;
+  if (empty())
+    return;
+
+  for (std::vector<char>::const_iterator
+         I = Buffer.begin(), E = Buffer.end(); I != E; ++I) {
+    if (*I == '\n')
+      ++NumLines;
+  }
+  if (Buffer.back() != '\n')
+    ++NumLines;
+}
diff --git a/lib/Frontend/CompilerInstance.cpp b/lib/Frontend/CompilerInstance.cpp
index 92798c8..924864c 100644
--- a/lib/Frontend/CompilerInstance.cpp
+++ b/lib/Frontend/CompilerInstance.cpp
@@ -539,11 +539,8 @@
                                                FileManager &FileMgr,
                                                SourceManager &SourceMgr,
                                                const FrontendOptions &Opts) {
-  // Figure out where to get and map in the main file, unless it's already
-  // been created (e.g., by a precompiled preamble).
-  if (!SourceMgr.getMainFileID().isInvalid()) {
-    // Do nothing: the main file has already been set.
-  } else if (InputFile != "-") {
+  // Figure out where to get and map in the main file.
+  if (InputFile != "-") {
     const FileEntry *File = FileMgr.getFile(InputFile);
     if (!File) {
       Diags.Report(diag::err_fe_error_reading) << InputFile;
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 0f3cad5..02d7eea 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -2508,23 +2508,15 @@
   if (DeserializationListener)
     DeserializationListener->ReaderInitialized(this);
 
-  // If this AST file is a precompiled preamble, then set the main file ID of 
-  // the source manager to the file source file from which the preamble was
-  // built. This is the only valid way to use a precompiled preamble.
+  // If this AST file is a precompiled preamble, then set the preamble file ID
+  // of the source manager to the file source file from which the preamble was
+  // built.
   if (Type == MK_Preamble) {
-    if (OriginalFileID.isInvalid()) {
-      SourceLocation Loc
-        = SourceMgr.getLocation(FileMgr.getFile(getOriginalSourceFile()), 1, 1);
-      if (Loc.isValid())
-        OriginalFileID = SourceMgr.getDecomposedLoc(Loc).first;
-    }
-    else {
+    if (!OriginalFileID.isInvalid()) {
       OriginalFileID = FileID::get(ModuleMgr.getPrimaryModule().SLocEntryBaseID
                                         + OriginalFileID.getOpaqueValue() - 1);
+      SourceMgr.setPreambleFileID(OriginalFileID);
     }
-
-    if (!OriginalFileID.isInvalid())
-      SourceMgr.SetPreambleFileID(OriginalFileID);
   }
   
   return Success;