Ruby

Stop reading past the end of ivptr array

If you have code like this:

class A def initialize @a = nil @b = nil @c = nil @d = nil @e = nil end end x = A.new y = x.clone 100.times { |z| x.instance_variable_set(:"@foo#{z}", nil) } puts y.inspect 

x and y will share iv_index_tbl hashes. However, the size of the
hash will grow larger than the number if entries in ivptr in y.
Before this commit, rb_ivar_count would use the size of the hash to
determine how far to read in to the array, but this means that it could
read past the end of the array and cause the program to segv

[ruby-core:78403]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56938 b2dd03c8-39d4-4d8f-98ff-823fe69b080e