This adds the -profile-generate flag, which enables LLVM's
instrumentation based profiling. It implements the instrumentation
for basic control flow, such as if statements, loops, and closures.
Swift SVN r25155
Previously, the Parser and BranchStmt typedef-ed ExprStmtOrDecl as a pointer union. Using typedef made the objects compatible, but did not allow us to extend the type with helper methods, such as getSourceRange(), which is something you can get on all of the AST objects. This patch introduces ASTNode that subclasses from PointerUnion and is used by both parser and BranchStmt.
Swift SVN r9971
