Introduce a new BufferResult class to act as the return type of

SourceManager's getBuffer() (and similar) operations. This abstract
can be used to force callers to cope with errors in getBuffer(), such
as missing files and changed files. Fix a bunch of callers to use the
new interface.

Add some very basic checks for file consistency (file size,
modification time) into ContentCache::getBuffer(), although these
checks don't help much until we've updated the main callers (e.g.,
SourceManager::getSpelling()).



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@98585 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 22 insertions, 5 deletions

diff --git a/lib/Frontend/RewriteObjC.cpp b/lib/Frontend/RewriteObjC.cpp
index 3181a55088..cd3d4ee0b9 100644
--- a/lib/Frontend/RewriteObjC.cpp
+++ b/lib/Frontend/RewriteObjC.cpp
@@ -706,7 +706,11 @@ void RewriteObjC::HandleTopLevelSingleDecl(Decl *D) {
 
 void RewriteObjC::RewriteInclude() {
   SourceLocation LocStart = SM->getLocForStartOfFile(MainFileID);
-  std::pair<const char*, const char*> MainBuf = SM->getBufferData(MainFileID);
+  std::pair<const char*, const char*> MainBuf = SM->getBufferData(MainFileID, 
+                                                                  Diags);
+  if (!MainBuf.first)
+    return;
+  
   const char *MainBufStart = MainBuf.first;
   const char *MainBufEnd = MainBuf.second;
   size_t ImportLen = strlen("import");
@@ -731,7 +735,11 @@ void RewriteObjC::RewriteInclude() {
 }
 
 void RewriteObjC::RewriteTabs() {
-  std::pair<const char*, const char*> MainBuf = SM->getBufferData(MainFileID);
+  std::pair<const char*, const char*> MainBuf = SM->getBufferData(MainFileID,
+                                                                  Diags);
+  if (!MainBuf.first)
+    return;
+  
   const char *MainBufStart = MainBuf.first;
   const char *MainBufEnd = MainBuf.second;
 
@@ -973,7 +981,10 @@ void RewriteObjC::RewriteCategoryDecl(ObjCCategoryDecl *CatDecl) {
 }
 
 void RewriteObjC::RewriteProtocolDecl(ObjCProtocolDecl *PDecl) {
-  std::pair<const char*, const char*> MainBuf = SM->getBufferData(MainFileID);
+  std::pair<const char*, const char*> MainBuf = SM->getBufferData(MainFileID,
+                                                                  Diags);
+  if (!MainBuf.first)
+    return;
 
   SourceLocation LocStart = PDecl->getLocStart();
 
diff --git a/lib/Frontend/TextDiagnosticPrinter.cpp b/lib/Frontend/TextDiagnosticPrinter.cpp
index 60c1f4b9b8..2b243fad24 100644
--- a/lib/Frontend/TextDiagnosticPrinter.cpp
+++ b/lib/Frontend/TextDiagnosticPrinter.cpp
@@ -330,9 +330,15 @@ void TextDiagnosticPrinter::EmitCaretDiagnostic(SourceLocation Loc,
   unsigned FileOffset = LocInfo.second;
 
   // Get information about the buffer it points into.
-  std::pair<const char*, const char*> BufferInfo = SM.getBufferData(FID);
+  llvm::StringRef ErrorFileName;
+  std::string ErrorStr;
+  std::pair<const char*, const char*> BufferInfo = SM.getBufferData(FID, 
+                                                                  ErrorFileName,
+                                                                    ErrorStr);
   const char *BufStart = BufferInfo.first;
-
+  if (!BufStart)
+    return;
+  
   unsigned ColNo = SM.getColumnNumber(FID, FileOffset);
   unsigned CaretEndColNo
     = ColNo + Lexer::MeasureTokenLength(Loc, SM, *LangOpts);