[cfe-commits] r69755 - in /cfe/trunk: include/clang/Frontend/PCHBitCodes.h include/clang/Frontend/PCHReader.h include/clang/Frontend/PCHWriter.h lib/Frontend/PCHReader.cpp lib/Frontend/PCHWriter.cpp

[Chris Lattner]

On Apr 21, 2009, at 4:56 PM, Douglas Gregor wrote:

> Author: dgregor
> Date: Tue Apr 21 18:56:24 2009
> New Revision: 69755
>
> URL: http://llvm.org/viewvc/llvm-project?rev=69755&view=rev
> Log:
> Lazy deserialization of macro definitions for precompiled headers.
>
> This optimization improves performance on the Carbon-prefixed "Hello,
> World!" example by 57%. For reference, we're now about 2.25x faster
> than GCC PCH. We're also pulling in far less of the PCH file:
>
> *** PCH Statistics:
>  411/20693 types read (1.986179%)
>  2553/59230 declarations read (4.310316%)
>  1093/44646 identifiers read (2.448148%)
>  1/32954 statements read (0.003035%)
>  21/6187 macros read (0.339421%)

Very nice!  Why are we still pulling in thousands of identifiers and  
decls?

-Chris