clang/StaticAnalyzer: Stop using SourceManager::getBuffer

Update clang/lib/StaticAnalyzer to stop relying on a `MemoryBuffer*`,
using the `MemoryBufferRef` from `getBufferOrNone` or the
`Optional<MemoryBufferRef>` from `getBufferOrFake`, depending on whether
there's logic for checking validity of the buffer. The change to
clang/lib/StaticAnalyzer/Core/IssueHash.cpp is potentially a
functionality change, since the logic was wrong (it checked for
`nullptr`, which was never returned by the old API), but if that was
reachable the new behaviour should be better.

Differential Revision: https://reviews.llvm.org/D89414

clang/lib/StaticAnalyzer/Checkers/LocalizationChecker.cpp

@@ -1141,10 +1141,9 @@ void EmptyLocalizationContextChecker::MethodCrawler::VisitObjCMessageExpr(
     SE = Mgr.getSourceManager().getSLocEntry(SLInfo.first);
   }
 
-  bool Invalid = false;
-  const llvm::MemoryBuffer *BF =
-      Mgr.getSourceManager().getBuffer(SLInfo.first, SL, &Invalid);
-  if (Invalid)
+  llvm::Optional<llvm::MemoryBufferRef> BF =
+      Mgr.getSourceManager().getBufferOrNone(SLInfo.first, SL);
+  if (!BF)
     return;
 
   Lexer TheLexer(SL, LangOptions(), BF->getBufferStart(),

clang/lib/StaticAnalyzer/Core/BugReporter.cpp

@@ -1570,9 +1570,8 @@ static Optional<size_t> getLengthOnSingleLine(const SourceManager &SM,
   if (FID != SM.getFileID(ExpansionRange.getEnd()))
     return None;
 
-  bool Invalid;
-  const llvm::MemoryBuffer *Buffer = SM.getBuffer(FID, &Invalid);
-  if (Invalid)
+  Optional<MemoryBufferRef> Buffer = SM.getBufferOrNone(FID);
+  if (!Buffer)
     return None;
 
   unsigned BeginOffset = SM.getFileOffset(ExpansionRange.getBegin());

clang/lib/StaticAnalyzer/Core/HTMLDiagnostics.cpp

@@ -786,8 +786,8 @@ void HTMLDiagnostics::HandlePiece(Rewriter &R, FileID BugFileID,
   if (LPosInfo.first != BugFileID)
     return;
 
-  const llvm::MemoryBuffer *Buf = SM.getBuffer(LPosInfo.first);
-  const char* FileStart = Buf->getBufferStart();
+  llvm::MemoryBufferRef Buf = SM.getBufferOrFake(LPosInfo.first);
+  const char *FileStart = Buf.getBufferStart();
 
   // Compute the column number.  Rewind from the current position to the start
   // of the line.
@@ -797,7 +797,7 @@ void HTMLDiagnostics::HandlePiece(Rewriter &R, FileID BugFileID,
 
   // Compute LineEnd.
   const char *LineEnd = TokInstantiationPtr;
-  const char* FileEnd = Buf->getBufferEnd();
+  const char *FileEnd = Buf.getBufferEnd();
   while (*LineEnd != '\n' && LineEnd != FileEnd)
     ++LineEnd;
 

clang/lib/StaticAnalyzer/Core/IssueHash.cpp

@@ -120,7 +120,8 @@ static std::string GetEnclosingDeclContextSignature(const Decl *D) {
   return "";
 }
 
-static StringRef GetNthLineOfFile(const llvm::MemoryBuffer *Buffer, int Line) {
+static StringRef GetNthLineOfFile(llvm::Optional<llvm::MemoryBufferRef> Buffer,
+                                  int Line) {
   if (!Buffer)
     return "";
 
@@ -135,7 +136,7 @@ static std::string NormalizeLine(const SourceManager &SM, FullSourceLoc &L,
                                  const LangOptions &LangOpts) {
   static StringRef Whitespaces = " \t\n";
 
-  StringRef Str = GetNthLineOfFile(SM.getBuffer(L.getFileID(), L),
+  StringRef Str = GetNthLineOfFile(SM.getBufferOrNone(L.getFileID(), L),
                                    L.getExpansionLineNumber());
   StringRef::size_type col = Str.find_first_not_of(Whitespaces);
   if (col == StringRef::npos)
@@ -144,8 +145,8 @@ static std::string NormalizeLine(const SourceManager &SM, FullSourceLoc &L,
     col++;
   SourceLocation StartOfLine =
       SM.translateLineCol(SM.getFileID(L), L.getExpansionLineNumber(), col);
-  const llvm::MemoryBuffer *Buffer =
-      SM.getBuffer(SM.getFileID(StartOfLine), StartOfLine);
+  Optional<llvm::MemoryBufferRef> Buffer =
+      SM.getBufferOrNone(SM.getFileID(StartOfLine), StartOfLine);
   if (!Buffer)
     return {};
 

clang/lib/StaticAnalyzer/Core/PlistDiagnostics.cpp

@@ -887,12 +887,12 @@ public:
     FileID File;
     unsigned Offset;
     std::tie(File, Offset) = SM.getDecomposedLoc(ExpanLoc);
-    const llvm::MemoryBuffer *MB = SM.getBuffer(File);
-    const char *MacroNameTokenPos = MB->getBufferStart() + Offset;
+    llvm::MemoryBufferRef MB = SM.getBufferOrFake(File);
+    const char *MacroNameTokenPos = MB.getBufferStart() + Offset;
 
     RawLexer = std::make_unique<Lexer>(SM.getLocForStartOfFile(File), LangOpts,
-                                       MB->getBufferStart(), MacroNameTokenPos,
-                                       MB->getBufferEnd());
+                                       MB.getBufferStart(), MacroNameTokenPos,
+                                       MB.getBufferEnd());
   }
 
   void next(Token &Result) {

clang/lib/StaticAnalyzer/Core/SarifDiagnostics.cpp

@@ -160,9 +160,8 @@ static unsigned int adjustColumnPos(const SourceManager &SM, SourceLocation Loc,
   assert(LocInfo.second > SM.getExpansionColumnNumber(Loc) &&
          "position in file is before column number?");
 
-  bool InvalidBuffer = false;
-  const MemoryBuffer *Buf = SM.getBuffer(LocInfo.first, &InvalidBuffer);
-  assert(!InvalidBuffer && "got an invalid buffer for the location's file");
+  Optional<MemoryBufferRef> Buf = SM.getBufferOrNone(LocInfo.first);
+  assert(Buf && "got an invalid buffer for the location's file");
   assert(Buf->getBufferSize() >= (LocInfo.second + TokenLen) &&
          "token extends past end of buffer?");
 

clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp

@@ -476,7 +476,7 @@ void AnalysisConsumer::HandleDeclsCallGraph(const unsigned LocalTUDeclsSize) {
 static bool isBisonFile(ASTContext &C) {
   const SourceManager &SM = C.getSourceManager();
   FileID FID = SM.getMainFileID();
-  StringRef Buffer = SM.getBuffer(FID)->getBuffer();
+  StringRef Buffer = SM.getBufferOrFake(FID).getBuffer();
   if (Buffer.startswith("/* A Bison parser, made by"))
     return true;
   return false;