[llgo] Remove support for LLVM attributes

llgo supports the application of LLVM attributes to global objects
and functions.  This "feature" is undocumented and untested.  As
discusses in D27442, it should be removed.

Differential Revision: https://reviews.llvm.org/D27474

llvm-svn: 288843

llgo/irgen/attribute.go

@@ -74,8 +74,6 @@ func parseAttribute(line string) Attribute {
 		return parseLinkageAttribute(value)
 	case "name":
 		return nameAttribute(strings.TrimSpace(value))
-	case "attr":
-		return parseLLVMAttribute(strings.TrimSpace(value))
 	case "thread_local":
 		return tlsAttribute{}
 	default:
@@ -142,36 +140,6 @@ func (a nameAttribute) Apply(v llvm.Value) {
 	}
 }
 
-func parseLLVMAttribute(value string) llvmAttribute {
-	var result llvmAttribute
-	value = strings.Replace(value, ",", " ", -1)
-	for _, field := range strings.Fields(value) {
-		switch strings.ToLower(field) {
-		case "noreturn":
-		case "nounwind":
-		case "noinline":
-		case "alwaysinline":
-			kind := llvm.AttributeKindID(strings.ToLower(field))
-			result.AttrKinds = append(result.AttrKinds, kind)
-		}
-	}
-	return result
-}
-
-type llvmAttribute struct {
-	AttrKinds []uint
-}
-
-func (a llvmAttribute) Apply(v llvm.Value) {
-	ctx := v.GlobalParent().Context()
-	if !v.IsAFunction().IsNil() {
-		for _, kind := range a.AttrKinds {
-			attr := ctx.CreateEnumAttribute(kind, 0)
-			v.AddFunctionAttr(attr)
-		}
-	}
-}
-
 type tlsAttribute struct{}
 
 func (tlsAttribute) Apply(v llvm.Value) {