[PATCH] D25363: [Sema] Store a SourceRange for multi-token builtin types

[Malcolm Parsons via cfe-commits]

malcolm.parsons added inline comments.


================
Comment at: include/clang/AST/TypeLoc.h:513
 struct BuiltinLocInfo {
-  SourceLocation BuiltinLoc;
+  SourceRange BuiltinRange;
 };
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aaron.ballman wrote:
> malcolm.parsons wrote:
> > aaron.ballman wrote:
> > > Since this doubles the size of the type loc for builtin types, do you happen to have any data on what practical impact this has on RAM usage, say for bootstrapping LLVM (or compiling any large source base, really)? Hopefully it's not a lot, but it would be nice to know if it's a .1%, 1%, 10%, etc increase in usage (or does the change get lost in the noise).
> > I don't have any data.
> > I'm not sure how to collect that data.
> It's likely platform dependent, but I was thinking something as simple as looking at peak RAM usage between two different builds of the compiler. Something like `top` would probably work if you're on Linux (unless someone knows of a better way, I'm not strong on Linux).
Before:
/usr/bin/time clang++ ... -c llvm/tools/clang/lib/AST/ExprConstant.cpp
5.56user 0.13system 0:05.91elapsed 96%CPU (0avgtext+0avgdata 256820maxresident)k

After:
/usr/bin/time clang++ ... -c llvm/tools/clang/lib/AST/ExprConstant.cpp
5.67user 0.12system 0:05.98elapsed 97%CPU (0avgtext+0avgdata 256940maxresident)k

((256940 - 256820) / 256820) * 100 = 0.05%


https://reviews.llvm.org/D25363