Go back to having the clang driver create ASTContext explicitly, passing
it to Sema/ASTStreamer (separating the lifetime of ASTContext from
the lifetime of Sema). One day it might be useful to consider creating
a context object implicitly if one isn't provided (using default arguments in
Sema's constructor). At this point, adding this convenience isn't necessary.

llvm-svn: 39346

the prerocessor will be available via ASTContext).
- Removed the public data member "PP" in ASTContext.
- Changed ASTContext's contructor to take TargetInfo/IdentifierTable explicitly.
- Implicitly create an ASTContext in Sema's constructor. This simplifies
the clients job (and makes ASTContext more private).
--As a side effect, added a "PrintStats" hook to Sema.

To support this level of encapsulation, ASTContext is always dynamically
allocated (by Sema). Previously, ASTContext was being allocated on the
stack. I don't believe this should be a performance issue (since ASTContext
is fairly course grain and tied to the lifetime of Sema currently).

llvm-svn: 39345

*** AST Context Stats:
  30594 types total.
    19 builtin types
    3929 pointer types
    308 array types
    18883 function types with proto
    8 function types with no proto
    2988 typename (typedef) types
    4459 tagged types
      1476 struct types
      80 union types
      0 class types
      2903 enum types
  83298 slow type lookups

Next up, making type canonicalization not trivially silly.

llvm-svn: 39305

llvm-svn: 39161

interface exported by libast.

llvm-svn: 39154

llvm-svn: 39153

and should be implemented with an ASTBuilder subclass anyway.

llvm-svn: 39107

llvm-svn: 39095

declarations through the asm streamer.  For a testcase like:

int G;
int H, I, *J;
int func() {}

'clang -parse-print-ast' prints:

Read top-level decl: G
Read top-level decl: H
Read top-level decl: I
Read top-level decl: J
Read top-level decl: func

llvm-svn: 38992

llvm-svn: 38960

Add callbacks for same.
Add "full locinfo" mode.

llvm-svn: 38939

llvm-svn: 38938

llvm-svn: 38936

llvm-svn: 38935