Revert "Windows FPRs preservation (bytecodealliance#1216)"

This reverts commit 4cca510.

build.rs

@@ -194,17 +194,6 @@ fn ignore(testsuite: &str, testname: &str, strategy: &str) -> bool {
             ("reference_types", "table_copy_on_imported_tables") => return false,
             ("reference_types", _) => return true,
 
-            ("misc_testsuite", "export_large_signature")
-            | ("spec_testsuite", "call")
-            | ("multi_value", "call")
-            | ("multi_value", "func") => {
-                // FIXME These involves functions with very large stack frames that Cranelift currently
-                // cannot compile using the fastcall (Windows) calling convention.
-                // See https://github.com/bytecodealliance/wasmtime/pull/1216.
-                #[cfg(windows)]
-                return true;
-            }
-
             _ => {}
         },
         _ => panic!("unrecognized strategy"),

cranelift/codegen/src/context.rs

@@ -206,8 +206,8 @@ impl Context {
         isa: &dyn TargetIsa,
         kind: FrameUnwindKind,
         sink: &mut dyn FrameUnwindSink,
-    ) -> CodegenResult<()> {
-        isa.emit_unwind_info(&self.func, kind, sink)
+    ) {
+        isa.emit_unwind_info(&self.func, kind, sink);
     }
 
     /// Run the verifier on the function.

cranelift/codegen/src/isa/mod.rs

@@ -398,9 +398,8 @@ pub trait TargetIsa: fmt::Display + Send + Sync {
         _func: &ir::Function,
         _kind: binemit::FrameUnwindKind,
         _sink: &mut dyn binemit::FrameUnwindSink,
-    ) -> CodegenResult<()> {
+    ) {
         // No-op by default
-        Ok(())
     }
 }
 

cranelift/codegen/src/isa/x86/fde.rs

@@ -4,7 +4,6 @@ use crate::binemit::{FrameUnwindOffset, FrameUnwindSink, Reloc};
 use crate::ir::{FrameLayoutChange, Function};
 use crate::isa::fde::RegisterMappingError;
 use crate::isa::{CallConv, RegUnit, TargetIsa};
-use crate::result::CodegenResult;
 use alloc::vec::Vec;
 use core::convert::TryInto;
 use gimli::write::{
@@ -179,11 +178,7 @@ fn to_cfi(
 }
 
 /// Creates FDE structure from FrameLayout.
-pub fn emit_fde(
-    func: &Function,
-    isa: &dyn TargetIsa,
-    sink: &mut dyn FrameUnwindSink,
-) -> CodegenResult<()> {
+pub fn emit_fde(func: &Function, isa: &dyn TargetIsa, sink: &mut dyn FrameUnwindSink) {
     assert!(isa.name() == "x86");
 
     // Expecting function with System V prologue
@@ -271,8 +266,6 @@ pub fn emit_fde(
 
     // Need 0 marker for GCC unwind to end FDE "list".
     sink.bytes(&[0, 0, 0, 0]);
-
-    Ok(())
 }
 
 #[cfg(test)]
@@ -321,7 +314,7 @@ mod tests {
         context.compile(&*isa).expect("expected compilation");
 
         let mut sink = SimpleUnwindSink(Vec::new(), 0, Vec::new());
-        emit_fde(&context.func, &*isa, &mut sink).expect("can emit fde");
+        emit_fde(&context.func, &*isa, &mut sink);
 
         assert_eq!(
             sink.0,
@@ -383,7 +376,7 @@ mod tests {
         context.compile(&*isa).expect("expected compilation");
 
         let mut sink = SimpleUnwindSink(Vec::new(), 0, Vec::new());
-        emit_fde(&context.func, &*isa, &mut sink).expect("can emit fde");
+        emit_fde(&context.func, &*isa, &mut sink);
 
         assert_eq!(
             sink.0,

cranelift/codegen/src/isa/x86/mod.rs

@@ -177,8 +177,8 @@ impl TargetIsa for Isa {
         func: &ir::Function,
         kind: FrameUnwindKind,
         sink: &mut dyn FrameUnwindSink,
-    ) -> CodegenResult<()> {
-        abi::emit_unwind_info(func, self, kind, sink)
+    ) {
+        abi::emit_unwind_info(func, self, kind, sink);
     }
 }