78c3091e84
This commit fixes both how FPR callee-saved registers are saved and how the shadow space allocation occurs when laying out the stack for Windows x64 calling convention. Importantly, this commit removes the compiler limitation of stack size for Windows x64 that was imposed because FPR saves previously couldn't always be represented in the unwind information. The FPR saves are now performed without using stack slots, much like how the callee-saved GPRs are saved. The total CSR space is given to `layout_stack` so that it is included in the frame size and to offset the layout of spills and explicit slots. The FPR saves are now done via an RSP offset (post adjustment) and they always follow the GPR saves on the stack. A simpler calculation can now be made to determine the proper offsets of the FPR saves for representing the unwind information. Additionally, the shadow space is no longer treated as an incoming argument, but an explicit stack slot that gets laid out at the lowest address possible in the local frame. This prevents `layout_stack` from putting a spill or explicit slot in this reserved space. In the future, `layout_stack` should take advantage of the *caller-provided* shadow space for spills, but this commit does not attempt to address that. The shadow space is now omitted from the local frame for leaf functions. Fixes #1728. Fixes #1587. Fixes #1475.
This crate contains the core Cranelift code generator. It translates code from an intermediate representation into executable machine code.