Extend the source manager with the ability to override the contents of

files with the contents of an arbitrary memory buffer. Use this new
functionality to drastically clean up the way in which we handle file
truncation for code-completion: all of the truncation/completion logic
is now encapsulated in the preprocessor where it belongs
(<rdar://problem/7434737>).



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@90300 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 28 insertions, 78 deletions

diff --git a/lib/Basic/SourceManager.cpp b/lib/Basic/SourceManager.cpp
index c27675f38b..8cc7a8438d 100644
--- a/lib/Basic/SourceManager.cpp
+++ b/lib/Basic/SourceManager.cpp
@@ -41,66 +41,29 @@ unsigned ContentCache::getSizeBytesMapped() const {
 /// getSize - Returns the size of the content encapsulated by this ContentCache.
 ///  This can be the size of the source file or the size of an arbitrary
 ///  scratch buffer.  If the ContentCache encapsulates a source file, that
-///  file is not lazily brought in from disk to satisfy this query unless it
-///  needs to be truncated due to a truncateAt() call.
+///  file is not lazily brought in from disk to satisfy this query.
 unsigned ContentCache::getSize() const {
   return Buffer ? Buffer->getBufferSize() : Entry->getSize();
 }
 
+void ContentCache::replaceBuffer(const llvm::MemoryBuffer *B) {
+  if (B == Buffer)
+    return;
+  
+  delete Buffer;
+  Buffer = B;
+}
+
 const llvm::MemoryBuffer *ContentCache::getBuffer(std::string *ErrorStr) const {
   // Lazily create the Buffer for ContentCaches that wrap files.
   if (!Buffer && Entry) {
     // FIXME: Should we support a way to not have to do this check over
     //   and over if we cannot open the file?
     Buffer = MemoryBuffer::getFile(Entry->getName(), ErrorStr,Entry->getSize());
-    if (isTruncated())
-      const_cast<ContentCache *>(this)->truncateAt(TruncateAtLine, 
-                                                   TruncateAtColumn);
   }
   return Buffer;
 }
 
-void ContentCache::truncateAt(unsigned Line, unsigned Column) {
-  TruncateAtLine = Line;
-  TruncateAtColumn = Column;
-  
-  if (!isTruncated() || !Buffer)
-    return;
-  
-  // Find the byte position of the truncation point.
-  const char *Position = Buffer->getBufferStart();
-  for (unsigned Line = 1; Line < TruncateAtLine; ++Line) {
-    for (; *Position; ++Position) {
-      if (*Position != '\r' && *Position != '\n')
-        continue;
-      
-      // Eat \r\n or \n\r as a single line.
-      if ((Position[1] == '\r' || Position[1] == '\n') &&
-          Position[0] != Position[1])
-        ++Position;
-      ++Position;
-      break;
-    }
-  }
-  
-  for (unsigned Column = 1; Column < TruncateAtColumn; ++Column, ++Position) {
-    if (!*Position)
-      break;
-    
-    if (*Position == '\t')
-      Column += 7;
-  }
-  
-  // Truncate the buffer.
-  if (Position != Buffer->getBufferEnd()) {
-    MemoryBuffer *TruncatedBuffer 
-      = MemoryBuffer::getMemBufferCopy(Buffer->getBufferStart(), Position, 
-                                       Buffer->getBufferIdentifier());
-    delete Buffer;
-    Buffer = TruncatedBuffer;
-  }
-}
-
 unsigned LineTableInfo::getLineTableFilenameID(const char *Ptr, unsigned Len) {
   // Look up the filename in the string table, returning the pre-existing value
   // if it exists.
@@ -332,16 +295,6 @@ SourceManager::getOrCreateContentCache(const FileEntry *FileEnt) {
   EntryAlign = std::max(8U, EntryAlign);
   Entry = ContentCacheAlloc.Allocate<ContentCache>(1, EntryAlign);
   new (Entry) ContentCache(FileEnt);
-  
-  if (FileEnt == TruncateFile) {
-    // If we had queued up a file truncation request, perform the truncation
-    // now.
-    Entry->truncateAt(TruncateAtLine, TruncateAtColumn);
-    TruncateFile = 0;
-    TruncateAtLine = 0;
-    TruncateAtColumn = 0;
-  }
-  
   return Entry;
 }
 
@@ -457,6 +410,25 @@ SourceLocation SourceManager::createInstantiationLoc(SourceLocation SpellingLoc,
   return SourceLocation::getMacroLoc(NextOffset-(TokLength+1));
 }
 
+const llvm::MemoryBuffer *
+SourceManager::getMemoryBufferForFile(const FileEntry *File) {
+  const SrcMgr::ContentCache *IR = getOrCreateContentCache(File);
+  if (IR == 0)
+    return 0;
+
+  return IR->getBuffer();
+}
+
+bool SourceManager::overrideFileContents(const FileEntry *SourceFile,
+                                         const llvm::MemoryBuffer *Buffer) {
+  const SrcMgr::ContentCache *IR = getOrCreateContentCache(SourceFile);
+  if (IR == 0)
+    return true;
+
+  const_cast<SrcMgr::ContentCache *>(IR)->replaceBuffer(Buffer);
+  return false;
+}
+
 /// getBufferData - Return a pointer to the start and end of the source buffer
 /// data for the specified FileID.
 std::pair<const char*, const char*>
@@ -1124,28 +1096,6 @@ bool SourceManager::isBeforeInTranslationUnit(SourceLocation LHS,
   return LastResForBeforeTUCheck = (LOffs.first < ROffs.first);
 }
 
-void SourceManager::truncateFileAt(const FileEntry *Entry, unsigned Line, 
-                                   unsigned Column) {
-  llvm::DenseMap<const FileEntry*, SrcMgr::ContentCache*>::iterator FI
-     = FileInfos.find(Entry);
-  if (FI != FileInfos.end()) {
-    FI->second->truncateAt(Line, Column);
-    return;
-  }
-  
-  // We cannot perform the truncation until we actually see the file, so
-  // save the truncation information.
-  assert(TruncateFile == 0 && "Can't queue up multiple file truncations!");
-  TruncateFile = Entry;
-  TruncateAtLine = Line;
-  TruncateAtColumn = Column;
-}
-
-/// \brief Determine whether this file was truncated.
-bool SourceManager::isTruncatedFile(FileID FID) const {
-  return getSLocEntry(FID).getFile().getContentCache()->isTruncated();
-}
-
 /// PrintStats - Print statistics to stderr.
 ///
 void SourceManager::PrintStats() const {