[WebAssembly] Implement WASM_STACK_POINTER.

Use the .stack_pointer directive to implement WASM_STACK_POINTER for
specifying a global variable to be the stack pointer.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319797 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed