Revamp the SourceManager to separate the representation of parsed

source locations from source locations loaded from an AST/PCH file.

Previously, loading an AST/PCH file involved carefully pre-allocating
space at the beginning of the source manager for the source locations
and FileIDs that correspond to the prefix, and then appending the
source locations/FileIDs used for parsing the remaining translation
unit. This design forced us into loading PCH files early, as a prefix,
whic has become a rather significant limitation.

This patch splits the SourceManager space into two parts: for source
location "addresses", the lower values (growing upward) are used to
describe parsed code, while upper values (growing downward) are used
for source locations loaded from AST/PCH files. Similarly, positive
FileIDs are used to describe parsed code while negative FileIDs are
used to file/macro locations loaded from AST/PCH files. As a result,
we can load PCH/AST files even during parsing, making various
improvemnts in the future possible, e.g., teaching #include <foo.h> to
look for and load <foo.h.gch> if it happens to be already available.

This patch was originally written by Sebastian Redl, then brought
forward to the modern age by Jonathan Turner, and finally
polished/finished by me to be committed.




git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@135484 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 3 deletions

diff --git a/lib/Lex/Lexer.cpp b/lib/Lex/Lexer.cpp
index a28b8f6e7b..21522df75c 100644
--- a/lib/Lex/Lexer.cpp
+++ b/lib/Lex/Lexer.cpp
@@ -702,8 +702,8 @@ SourceLocation Lexer::getLocForEndOfToken(SourceLocation Loc, unsigned Offset,
 /// \brief Returns true if the given MacroID location points at the first
 /// token of the macro expansion.
 bool Lexer::isAtStartOfMacroExpansion(SourceLocation loc,
-                                          const SourceManager &SM,
-                                          const LangOptions &LangOpts) {
+                                      const SourceManager &SM,
+                                      const LangOptions &LangOpts) {
   assert(loc.isValid() && loc.isMacroID() && "Expected a valid macro loc");
 
   std::pair<FileID, unsigned> infoLoc = SM.getDecomposedLoc(loc);
@@ -735,7 +735,7 @@ bool Lexer::isAtEndOfMacroExpansion(SourceLocation loc,
 
   FileID FID = SM.getFileID(loc);
   SourceLocation afterLoc = loc.getFileLocWithOffset(tokLen+1);
-  if (!SM.isBeforeInSourceLocationOffset(afterLoc, SM.getNextOffset()))
+  if (!SM.isBeforeInSourceLocationOffset(afterLoc, SM.getNextLocalOffset()))
     return true; // We got past the last FileID, this points to the last token.
 
   // FIXME: If the token comes from the macro token paste operator ('##')