Summary:
- lowers @llvm.global_dtors by adding @llvm.global_ctors
functions which register the destructors with `__cxa_atexit`.
- impements @llvm.global_ctors with wasm start functions and linker metadata
See [here](https://github.com/WebAssembly/tool-conventions/issues/25) for more background.
Subscribers: jfb, dschuff, mgorny, jgravelle-google, aheejin, sunfish
Differential Revision: https://reviews.llvm.org/D41211
llvm-svn: 320774
Instead of having .o files contain linear-memory and function table
definitions, use imports. This is more consistent with the stack pointer
being imported, and it's consistent with the linker being the one to
decide whether linear memory and function table are imported or defined
in the linked output. This implements tool-conventions #23.
Differential Revision: https://reviews.llvm.org/D40875
llvm-svn: 319989
Sam Clegg