When deserializing a declaration, don't look for redeclarations if its
kind indicates that it can never be redeclared. Good for a 1% speedup,
and redeclaration searching drops off the profile.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173054 91177308-0d34-0410-b5e6-96231b3b80d8
Fixes formatting of empty blocks.

We now only put empty blocks into a single line, if all of:
- all tokens of the structural element fit into a single line
- we're not in a control flow statement

Note that we usually don't put record definitions into a single line, as
there's usually at least one more token (the semicolon) after the
closing brace. This doesn't hold when we are in a context where there is
no semicolon, like "enum E {}".

There were some missing tests around joining lines around the corner
cases of the allowed number of columns, so this patch adds some.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173055 91177308-0d34-0410-b5e6-96231b3b80d8
When loading an identifier from an AST file solely for the purpose of
forming the identifier, e.g., as part of a selector or a declaration
name, don't actually deserialize any information about the
identifier. Instead, simply mark it "out-of-date" and we'll load the
the information on demand. 2% speedup on the modules testcase I'm
looking at; should also help PCH.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173056 91177308-0d34-0410-b5e6-96231b3b80d8
Revert r173056; it breaks one of the CodeGen-with-PCH tests.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173058 91177308-0d34-0410-b5e6-96231b3b80d8