The 3rd of the 3 PRs needed for production Linux Segue support (i.e., use x86 segment registers to refer to the Wasm heap for single-memory Wasm modules). This PR adds an option for applications to tell wasm2c that it has exclusive use of the gs register for this purpose and need not save and restore it on each use --- something that is particularly expensive on pre-Ivybridge CPUs which requires syscalls to set segment registers.
The 3rd of the 3 PRs needed for production Linux Segue support (i.e., use x86 segment registers to refer to the Wasm heap for single-memory Wasm modules). This PR adds an option for applications to tell wasm2c that it has exclusive use of the gs register for this purpose and need not save and restore it on each use --- something that is particularly expensive on pre-Ivybridge CPUs which requires syscalls to set segment registers.