[PATCH] D119177: [demangler] Fix buffer growth

[Nathan Sidwell via Phabricator via llvm-commits]

urnathan added inline comments.


================
Comment at: libcxxabi/src/demangle/Utility.h:42
+      if (Need > BufferCapacity) {
+        if (!BufferCapacity && Need < 100)
+          // Avoid many reallocations during startup
----------------
ChuanqiXu wrote:
> What's the meaning of the magic number 100? Generally we should make it configurable or at least we should give a name to it.
It seems dramatically over-engineering to make this configurable. You just want a number high enough for many symbols in one go, and big enough that larger symbols don't keep reallocating.  But not so big that one allocates a tremendously excessive amount.  The demangler Nodes themselves are probably the largest component?

100 seemed a good enough value.  It's better than the current [non-configurable] zero :)  I notice the demangler's node allocator (BumpPointerAllocator) allocates [unconfigurable] 4096 byte blocks.  So let's go with 1024 here, ok?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D119177/new/

https://reviews.llvm.org/D119177