[meta] Move x86 registers generation to their own file;

cranelift/codegen/meta/src/isa/x86/registers.rs

@@ -0,0 +1,42 @@
+use crate::cdsl::regs::{IsaRegs, IsaRegsBuilder, RegBankBuilder, RegClassBuilder};
+
+pub fn define() -> IsaRegs {
+    let mut regs = IsaRegsBuilder::new();
+
+    let builder = RegBankBuilder::new("IntRegs", "r")
+        .units(16)
+        .names(vec!["rax", "rcx", "rdx", "rbx", "rsp", "rbp", "rsi", "rdi"])
+        .track_pressure(true);
+    let int_regs = regs.add_bank(builder);
+
+    let builder = RegBankBuilder::new("FloatRegs", "xmm")
+        .units(16)
+        .track_pressure(true);
+    let float_regs = regs.add_bank(builder);
+
+    let builder = RegBankBuilder::new("FlagRegs", "")
+        .units(1)
+        .names(vec!["rflags"])
+        .track_pressure(false);
+    let flag_reg = regs.add_bank(builder);
+
+    let builder = RegClassBuilder::new_toplevel("GPR", int_regs);
+    let gpr = regs.add_class(builder);
+
+    let builder = RegClassBuilder::new_toplevel("FPR", float_regs);
+    let fpr = regs.add_class(builder);
+
+    let builder = RegClassBuilder::new_toplevel("FLAG", flag_reg);
+    regs.add_class(builder);
+
+    let builder = RegClassBuilder::subclass_of("GPR8", gpr, 0, 8);
+    let gpr8 = regs.add_class(builder);
+
+    let builder = RegClassBuilder::subclass_of("ABCD", gpr8, 0, 4);
+    regs.add_class(builder);
+
+    let builder = RegClassBuilder::subclass_of("FPR8", fpr, 0, 8);
+    regs.add_class(builder);
+
+    regs.finish()
+}