[Sema][NFCI] Don't allocate storage for the various CorrectionCandidateCallback unless we are going to do some typo correction
The various CorrectionCandidateCallbacks are currently heap-allocated
unconditionally. This was needed because of delayed typo correction.
However these allocations represent currently 15.4% of all allocations
(number of allocations) when parsing all of Boost (!), mostly because
of ParseCastExpression, ParseStatementOrDeclarationAfterAttrtibutes
and isCXXDeclarationSpecifier. Note that all of these callback objects
are small. Let's not do this.
Instead initially allocate the callback on the stack, and only do a
heap allocation if we are going to do some typo correction. Do this by:
1. Adding a clone function to each callback, which will do a polymorphic
clone of the callback. This clone function is required to be implemented
by every callback (of which there is a fair amount). Make sure this is
the case by making it pure virtual.
2. Use this clone function when we are going to try to correct a typo.
This additionally cut the time of -fsyntax-only on all of Boost by 0.5%
(not that much, but still something). No functional changes intended.
Differential Revision: https://reviews.llvm.org/D58827
Reviewed By: rnk
llvm-svn: 356925
diff --git a/clang/lib/Parse/ParseStmt.cpp b/clang/lib/Parse/ParseStmt.cpp
index 2db3132..cee1605 100644
--- a/clang/lib/Parse/ParseStmt.cpp
+++ b/clang/lib/Parse/ParseStmt.cpp
@@ -116,7 +116,7 @@
}
namespace {
-class StatementFilterCCC : public CorrectionCandidateCallback {
+class StatementFilterCCC final : public CorrectionCandidateCallback {
public:
StatementFilterCCC(Token nextTok) : NextToken(nextTok) {
WantTypeSpecifiers = nextTok.isOneOf(tok::l_paren, tok::less, tok::l_square,
@@ -139,6 +139,10 @@
return CorrectionCandidateCallback::ValidateCandidate(candidate);
}
+ std::unique_ptr<CorrectionCandidateCallback> clone() override {
+ return llvm::make_unique<StatementFilterCCC>(*this);
+ }
+
private:
Token NextToken;
};
@@ -181,9 +185,8 @@
if (Next.isNot(tok::coloncolon)) {
// Try to limit which sets of keywords should be included in typo
// correction based on what the next token is.
- if (TryAnnotateName(/*IsAddressOfOperand*/ false,
- llvm::make_unique<StatementFilterCCC>(Next)) ==
- ANK_Error) {
+ StatementFilterCCC CCC(Next);
+ if (TryAnnotateName(/*IsAddressOfOperand*/ false, &CCC) == ANK_Error) {
// Handle errors here by skipping up to the next semicolon or '}', and
// eat the semicolon if that's what stopped us.
SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch);