For instance array.c:rb_ary_product() uses RSTRING_PTR() as an
array of int. So to avoid misaligned memory access RSTRING_PTR()
must at least be sizeof(int)-aligned. However the type of
RSTRING_PTR() is char*, which of course can expect alignment as
much as 1. This is a problem.
The reality is, there is no misaligned memory access because the
memory region behind RSTRING_PTR() is allocated using malloc().
Memory regions returned from malloc() are always aligned
appropriately. So let's tell the compiler about this information.
It seems GCC, clang, and MSVC have such feature.
Added by shyouhei (Shyouhei Urabe) almost 8 years ago
attibute((aligned)) for RSTRING_PTR()
For instance array.c:rb_ary_product() uses RSTRING_PTR() as an
array of int. So to avoid misaligned memory access RSTRING_PTR()
must at least be sizeof(int)-aligned. However the type of
RSTRING_PTR() is char*, which of course can expect alignment as
much as 1. This is a problem.
The reality is, there is no misaligned memory access because the
memory region behind RSTRING_PTR() is allocated using malloc().
Memory regions returned from malloc() are always aligned
appropriately. So let's tell the compiler about this information.
It seems GCC, clang, and MSVC have such feature.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61827 b2dd03c8-39d4-4d8f-98ff-823fe69b080e