On Fri, Feb 28, 2014 at 05:59:13AM -0800, Nathan Froyd wrote: > ----- Original Message ----- > > http://en.wikipedia.org/wiki/Plain_Old_Data_Structures > > > > > > confirms that POD can't have a vptr :-) > > > class Interface { > public: > constexpr Interface() {} > virtual int f() = 0; > }; > > class Concrete : public Interface { > public: > constexpr Concrete() {} > virtual int f(); > }; > > Concrete c; > > run through |g++ -std=c++0x -O2 -o - -S| (gcc 4.6, x86-64) gives: > > .file "vtables.cpp" > .globl c > .data > .align 8 > .type c, @object > .size c, 8 > c: > .quad _ZTV8Concrete+16 > > No initialization code in sight. clang does the same, with or without the > constexpr.
I think the actually tricky part of making the atoms themselves live in rodata is that they need to be layed out as if they were in a hash table so that we can get the atom for a string in O(1). I think we could do that by reimplementing some bits of the hash table in python and then spewing out a giant .S file layed out as if its a hash table, but seems like a bit of work and its not clear off hand to me that it would be a big win. Trev > > -Nathan > _______________________________________________ > dev-platform mailing list > dev-platform@lists.mozilla.org > https://lists.mozilla.org/listinfo/dev-platform _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
