Ruby

Implement equality for CI comparison when CC searching

When we're searching for CCs, compare the argc and flags for CI rather
than comparing pointers. This means we don't need to store a reference
to the CI, and it also naturally "de-duplicates" CC objects.

We can observe the effect with the following code:

require "objspace"

hash = {}

p ObjectSpace.memsize_of(Hash)

eval ("a".."zzz").map { |key|
  "hash.merge(:#{key} => 1)"
}.join("; ")

p ObjectSpace.memsize_of(Hash)

On master:

$ ruby -v test.rb
ruby 3.4.0dev (2024-04-15T16:21:41Z master d019b3baec) [arm64-darwin23]
test.rb:3: warning: assigned but unused variable - hash
3424
527736

On this branch:

$ make runruby
compiling vm.c
linking miniruby
builtin_binary.inc updated
compiling builtin.c
linking static-library libruby.3.4-static.a
ln -sf ../../rbconfig.rb .ext/arm64-darwin23/rbconfig.rb
linking ruby
ld: warning: ignoring duplicate libraries: '-ldl', '-lobjc', '-lpthread'
RUBY_ON_BUG='gdb -x ./.gdbinit -p' ./miniruby -I./lib -I. -I.ext/common  ./tool/runruby.rb --extout=.ext  -- --disable-gems  ./test.rb
2240
2368

Co-authored-by: John Hawthorn [email protected]