[PATCH] D17034: Add an AST matcher for null pointers

[Samuel Benzaquen via cfe-commits]

sbenza added inline comments.

================
Comment at: include/clang/ASTMatchers/ASTMatchers.h:4821
@@ +4820,3 @@
+///   initializer for i.
+AST_MATCHER(Expr, nullPointerConstant) {
+  return Matcher<Expr>(
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aaron.ballman wrote:
> aaron.ballman wrote:
> > sbenza wrote:
> > > sbenza wrote:
> > > > Use AST_MATCHER_FUNCTION instead, where the return value is the matcher (instead of the application of the matcher).
> > > > It is simpler to write and since it has no arguments it will memoize the matcher and construct it only once.
> > > Maybe use Expr::isNullPointerConstant?
> > Ah, interesting! I hadn't known about that macro. Thank you.
> Oh, hey, that's easier still! Would I still use AST_MATCHER_FUNCTION in that case though, or should that remain a simple AST_MATCHER?
One or the other.
The _FUNCTION macro is for when the matcher itself is just a matcher expression. Saves typing and CPU.
Generating the temporary matchers on each match is expensive as they do memory allocation.
If you use Expr::isNullPointerConstant you won't be making any matchers.



http://reviews.llvm.org/D17034