Add fixed_nonallocatable constraints when appropriate (#5253)

Plumb the set of allocatable registers through the OperandCollector and use it validate uses of fixed-nonallocatable registers, like %rsp on x86_64.

cranelift/codegen/src/isa/x64/mod.rs

@@ -48,14 +48,13 @@ impl X64Backend {
     fn compile_vcode(
         &self,
         func: &Function,
-        flags: Flags,
     ) -> CodegenResult<(VCode<inst::Inst>, regalloc2::Output)> {
         // This performs lowering to VCode, register-allocates the code, computes
         // block layout and finalizes branches. The result is ready for binary emission.
-        let emit_info = EmitInfo::new(flags.clone(), self.x64_flags.clone());
+        let emit_info = EmitInfo::new(self.flags.clone(), self.x64_flags.clone());
         let sigs = SigSet::new::<abi::X64ABIMachineSpec>(func, &self.flags)?;
         let abi = abi::X64Callee::new(&func, self, &self.x64_flags, &sigs)?;
-        compile::compile::<Self>(&func, flags, self, abi, &self.reg_env, emit_info, sigs)
+        compile::compile::<Self>(&func, self, abi, emit_info, sigs)
     }
 }
 
@@ -65,10 +64,13 @@ impl TargetIsa for X64Backend {
         func: &Function,
         want_disasm: bool,
     ) -> CodegenResult<CompiledCodeStencil> {
-        let flags = self.flags();
-        let (vcode, regalloc_result) = self.compile_vcode(func, flags.clone())?;
+        let (vcode, regalloc_result) = self.compile_vcode(func)?;
 
-        let emit_result = vcode.emit(&regalloc_result, want_disasm, flags.machine_code_cfg_info());
+        let emit_result = vcode.emit(
+            &regalloc_result,
+            want_disasm,
+            self.flags.machine_code_cfg_info(),
+        );
         let frame_size = emit_result.frame_size;
         let value_labels_ranges = emit_result.value_labels_ranges;
         let buffer = emit_result.buffer.finish();
@@ -96,6 +98,10 @@ impl TargetIsa for X64Backend {
         &self.flags
     }
 
+    fn machine_env(&self) -> &MachineEnv {
+        &self.reg_env
+    }
+
     fn isa_flags(&self) -> Vec<shared_settings::Value> {
         self.x64_flags.iter().collect()
     }