transform: remove switched func lowering

The switched func lowering was mainly necessary for coroutines.
With coroutines removed, this is no longer necessary.

compiler/testdata/func-none.ll

@@ -1,55 +0,0 @@
-; ModuleID = 'func.go'
-source_filename = "func.go"
-target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128-ni:1:10:20"
-target triple = "wasm32-unknown-wasi"
-
-%runtime.funcValueWithSignature = type { i32, i8* }
-
-@"reflect/types.funcid:func:{basic:int}{}" = external constant i8
-@"main.someFunc$withSignature" = linkonce_odr constant %runtime.funcValueWithSignature { i32 ptrtoint (void (i32, i8*, i8*)* @main.someFunc to i32), i8* @"reflect/types.funcid:func:{basic:int}{}" }
-
-declare noalias nonnull i8* @runtime.alloc(i32, i8*, i8*, i8*)
-
-declare void @runtime.trackPointer(i8* nocapture readonly, i8*, i8*)
-
-; Function Attrs: nounwind
-define hidden void @main.init(i8* %context, i8* %parentHandle) unnamed_addr #0 {
-entry:
-  ret void
-}
-
-; Function Attrs: nounwind
-define hidden void @main.foo(i8* %callback.context, i32 %callback.funcptr, i8* %context, i8* %parentHandle) unnamed_addr #0 {
-entry:
-  %0 = call i32 @runtime.getFuncPtr(i8* %callback.context, i32 %callback.funcptr, i8* nonnull @"reflect/types.funcid:func:{basic:int}{}", i8* undef, i8* null) #0
-  %1 = icmp eq i32 %0, 0
-  br i1 %1, label %fpcall.throw, label %fpcall.next
-
-fpcall.throw:                                     ; preds = %entry
-  call void @runtime.nilPanic(i8* undef, i8* null) #0
-  unreachable
-
-fpcall.next:                                      ; preds = %entry
-  %2 = inttoptr i32 %0 to void (i32, i8*, i8*)*
-  call void %2(i32 3, i8* %callback.context, i8* undef) #0
-  ret void
-}
-
-declare i32 @runtime.getFuncPtr(i8*, i32, i8* dereferenceable_or_null(1), i8*, i8*)
-
-declare void @runtime.nilPanic(i8*, i8*)
-
-; Function Attrs: nounwind
-define hidden void @main.bar(i8* %context, i8* %parentHandle) unnamed_addr #0 {
-entry:
-  call void @main.foo(i8* undef, i32 ptrtoint (%runtime.funcValueWithSignature* @"main.someFunc$withSignature" to i32), i8* undef, i8* undef)
-  ret void
-}
-
-; Function Attrs: nounwind
-define hidden void @main.someFunc(i32 %arg0, i8* %context, i8* %parentHandle) unnamed_addr #0 {
-entry:
-  ret void
-}
-
-attributes #0 = { nounwind }

compiler/testdata/func.ll

@@ -0,0 +1,47 @@
+; ModuleID = 'func.go'
+source_filename = "func.go"
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128-ni:1:10:20"
+target triple = "wasm32-unknown-wasi"
+
+declare noalias nonnull i8* @runtime.alloc(i32, i8*, i8*, i8*)
+
+declare void @runtime.trackPointer(i8* nocapture readonly, i8*, i8*)
+
+; Function Attrs: nounwind
+define hidden void @main.init(i8* %context, i8* %parentHandle) unnamed_addr #0 {
+entry:
+  ret void
+}
+
+; Function Attrs: nounwind
+define hidden void @main.foo(i8* %callback.context, void ()* %callback.funcptr, i8* %context, i8* %parentHandle) unnamed_addr #0 {
+entry:
+  %0 = icmp eq void ()* %callback.funcptr, null
+  br i1 %0, label %fpcall.throw, label %fpcall.next
+
+fpcall.throw:                                     ; preds = %entry
+  call void @runtime.nilPanic(i8* undef, i8* null) #0
+  unreachable
+
+fpcall.next:                                      ; preds = %entry
+  %1 = bitcast void ()* %callback.funcptr to void (i32, i8*, i8*)*
+  call void %1(i32 3, i8* %callback.context, i8* undef) #0
+  ret void
+}
+
+declare void @runtime.nilPanic(i8*, i8*)
+
+; Function Attrs: nounwind
+define hidden void @main.bar(i8* %context, i8* %parentHandle) unnamed_addr #0 {
+entry:
+  call void @main.foo(i8* undef, void ()* bitcast (void (i32, i8*, i8*)* @main.someFunc to void ()*), i8* undef, i8* undef)
+  ret void
+}
+
+; Function Attrs: nounwind
+define hidden void @main.someFunc(i32 %arg0, i8* %context, i8* %parentHandle) unnamed_addr #0 {
+entry:
+  ret void
+}
+
+attributes #0 = { nounwind }

compiler/testdata/gc.go

@@ -61,11 +61,6 @@ func newStruct() {
 }
 
 func newFuncValue() *func() {
-	// On some platforms that use runtime.funcValue ("switch" style) function
-	// values, a func value is allocated as having two pointer words while the
-	// struct looks like {unsafe.Pointer; uintptr}. This is so that the interp
-	// package won't get confused, see getPointerBitmap in compiler/llvm.go for
-	// details.
 	return new(func())
 }