Introduce optional "Invalid" parameters to routines that invoke the

SourceManager's getBuffer() and, therefore, could fail, along with
Preprocessor::getSpelling(). Use the Invalid parameters in the literal
parsers (string, floating point, integral, character) to make them
robust against errors that stem from, e.g., PCH files that are not
consistent with the underlying file system.

I still need to audit every use caller to all of these routines, to
determine which ones need specific handling of error conditions.

llvm-svn: 98608

1 files changed, 26 insertions, 9 deletions

diff --git a/clang/lib/Lex/Preprocessor.cpp b/clang/lib/Lex/Preprocessor.cpp
index a6efe7f5bcc..5584b18da15 100644
--- a/clang/lib/Lex/Preprocessor.cpp
+++ b/clang/lib/Lex/Preprocessor.cpp
@@ -282,11 +282,19 @@ bool Preprocessor::isCodeCompletionFile(SourceLocation FileLoc) const {
 /// UCNs, etc.
 std::string Preprocessor::getSpelling(const Token &Tok,
                                       const SourceManager &SourceMgr,
-                                      const LangOptions &Features) {
+                                      const LangOptions &Features, 
+                                      bool *Invalid) {
   assert((int)Tok.getLength() >= 0 && "Token character range is bogus!");
 
   // If this token contains nothing interesting, return it directly.
-  const char* TokStart = SourceMgr.getCharacterData(Tok.getLocation());
+  bool CharDataInvalid = false;
+  const char* TokStart = SourceMgr.getCharacterData(Tok.getLocation(), 
+                                                    &CharDataInvalid);
+  if (Invalid)
+    *Invalid = CharDataInvalid;
+  if (CharDataInvalid)
+    return std::string();
+
   if (!Tok.needsCleaning())
     return std::string(TokStart, TokStart+Tok.getLength());
 
@@ -310,8 +318,8 @@ std::string Preprocessor::getSpelling(const Token &Tok,
 /// after trigraph expansion and escaped-newline folding.  In particular, this
 /// wants to get the true, uncanonicalized, spelling of things like digraphs
 /// UCNs, etc.
-std::string Preprocessor::getSpelling(const Token &Tok) const {
-  return getSpelling(Tok, SourceMgr, Features);
+std::string Preprocessor::getSpelling(const Token &Tok, bool *Invalid) const {
+  return getSpelling(Tok, SourceMgr, Features, Invalid);
 }
 
 /// getSpelling - This method is used to get the spelling of a token into a
@@ -325,7 +333,7 @@ std::string Preprocessor::getSpelling(const Token &Tok) const {
 /// copy).  The caller is not allowed to modify the returned buffer pointer
 /// if an internal buffer is returned.
 unsigned Preprocessor::getSpelling(const Token &Tok,
-                                   const char *&Buffer) const {
+                                   const char *&Buffer, bool *Invalid) const {
   assert((int)Tok.getLength() >= 0 && "Token character range is bogus!");
 
   // If this token is an identifier, just return the string from the identifier
@@ -341,8 +349,16 @@ unsigned Preprocessor::getSpelling(const Token &Tok,
   if (Tok.isLiteral())
     TokStart = Tok.getLiteralData();
 
-  if (TokStart == 0)
-    TokStart = SourceMgr.getCharacterData(Tok.getLocation());
+  if (TokStart == 0) {
+    bool CharDataInvalid = false;
+    TokStart = SourceMgr.getCharacterData(Tok.getLocation(), &CharDataInvalid);
+    if (Invalid)
+      *Invalid = CharDataInvalid;
+    if (CharDataInvalid) {
+      Buffer = "";
+      return 0;
+    }
+  }
 
   // If this token contains nothing interesting, return it directly.
   if (!Tok.needsCleaning()) {
@@ -368,7 +384,8 @@ unsigned Preprocessor::getSpelling(const Token &Tok,
 /// SmallVector. Note that the returned StringRef may not point to the
 /// supplied buffer if a copy can be avoided.
 llvm::StringRef Preprocessor::getSpelling(const Token &Tok,
-                                    llvm::SmallVectorImpl<char> &Buffer) const {
+                                          llvm::SmallVectorImpl<char> &Buffer,
+                                          bool *Invalid) const {
   // Try the fast path.
   if (const IdentifierInfo *II = Tok.getIdentifierInfo())
     return II->getName();
@@ -378,7 +395,7 @@ llvm::StringRef Preprocessor::getSpelling(const Token &Tok,
     Buffer.resize(Tok.getLength());
 
   const char *Ptr = Buffer.data();
-  unsigned Len = getSpelling(Tok, Ptr);
+  unsigned Len = getSpelling(Tok, Ptr, Invalid);
   return llvm::StringRef(Ptr, Len);
 }