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%)
llvm-svn: 69755
identifiers from a precompiled header.
This patch changes the primary name lookup method for entities within
a precompiled header. Previously, we would load all of the names of
declarations at translation unit scope into a large DenseMap (inside
the TranslationUnitDecl's DeclContext), and then perform a special
"last resort" lookup into this DeclContext when we knew there was a
PCH file (see Sema::LookupName). Now, when we see an identifier named
for the first time, we load all of the declarations with that name
that are visible from the translation unit into the IdentifierInfo's
chain of declarations. Thus, the explicit "look into the translation
unit's DeclContext" code is gone, and Sema effectively uses the same
IdentifierInfo-based name lookup mechanism whether we are using a PCH
file or not.
This approach should help PCH scale with the size of the input program
rather than the size of the PCH file. The "Hello, World!" application
with Carbon.h as a PCH file now loads 20% of the identifiers in the
PCH file rather than 85% of the identifiers.
90% of the 20% of identifiers loaded are actually loaded when we
deserialize the preprocessor state. The next step is to make the
preprocessor load macros lazily, which should drastically reduce the
number of types, declarations, and identifiers loaded for "Hello,
World".
llvm-svn: 69737
that also includes the contents of the IdentifierInfo itself (the
various fields and flags, along with the chain of identifiers visible
at the top level that have that name).
We don't make any use of the hash table yet, except that our
identifier ID -> string mapping points into the hash table now.
llvm-svn: 69625
AST context's __builtin_va_list type will be set when the PCH file is
loaded. This fixes the crash when CodeGen'ing a va_arg expression
pulled in from a PCH file.
llvm-svn: 69421
"Hello, World!", this takes us from deserializing 6469
statements/expressions down to deserializing 1
statement/expression. It only translated into a 1% improvement on the
Carbon-prefixed 403.gcc, but (a) it's the right thing to do, and (b)
we expect this to matter more once we lazily deserialize identifiers.
llvm-svn: 69407
kind PCH handles that has an expression as an operand, so most of this
work is in the infrastructure to rebuild expression trees from the
serialized representation. We now store expressions in post-order
(e.g., Reverse Polish Notation), so that we can easily rebuild the
appropriate expression tree.
llvm-svn: 69101
This allows it to accurately measure tokens, so that we get:
t.cpp:8:13: error: unknown type name 'X'
static foo::X P;
~~~~~^
instead of the woefully inferior:
t.cpp:8:13: error: unknown type name 'X'
static foo::X P;
~~~~ ^
Most of this is just plumbing to push the reference around.
llvm-svn: 69099
Chris Lattner