Restrict Damian's magic hack to go 1.18 and above

Author: dkegel-fastly

builder/build.go

@@ -172,6 +172,7 @@ func Build(pkgName, outpath string, config *compileopts.Config, action func(Buil
 		AutomaticStackSize: config.AutomaticStackSize(),
 		DefaultStackSize:   config.Target.DefaultStackSize,
 		NeedsStackObjects:  config.NeedsStackObjects(),
+		GoMinorVersion:     config.GoMinorVersion,
 		Debug:              true,
 	}
 

compiler/compiler.go

@@ -50,6 +50,7 @@ type Config struct {
 	AutomaticStackSize bool
 	DefaultStackSize   uint64
 	NeedsStackObjects  bool
+	GoMinorVersion     int
 	Debug              bool // Whether to emit debug information in the LLVM module.
 }
 

compiler/interface.go

@@ -329,7 +329,7 @@ func (c *compilerContext) getInterfaceMethodSet(typ types.Type) llvm.Value {
 // getMethodSignatureName returns a unique name (that can be used as the name of
 // a global) for the given method.
 func (c *compilerContext) getMethodSignatureName(method *types.Func) string {
-	signature := methodSignature(method)
+	signature := c.methodSignature(method)
 	var globalName string
 	if token.IsExported(method.Name()) {
 		globalName = "reflect/methods." + signature
@@ -572,16 +572,16 @@ func (c *compilerContext) getInterfaceInvokeWrapper(fn *ssa.Function, llvmFn llv
 //
 //     String() string
 //     Read([]byte) (int, error)
-func methodSignature(method *types.Func) string {
-	return method.Name() + signature(method.Type().(*types.Signature))
+func (c *compilerContext) methodSignature(method *types.Func) string {
+	return method.Name() + c.signature(method.Type().(*types.Signature))
 }
 
 // Make a readable version of a function (pointer) signature.
 // Examples:
 //
 //     () string
 //     (string, int) (int, error)
-func signature(sig *types.Signature) string {
+func (c *compilerContext) signature(sig *types.Signature) string {
 	s := ""
 	if sig.Params().Len() == 0 {
 		s += "()"
@@ -591,29 +591,29 @@ func signature(sig *types.Signature) string {
 			if i > 0 {
 				s += ", "
 			}
-			s += emptyInterfaceToAny(sig.Params().At(i).Type().String())
+			s += c.emptyInterfaceToAny(sig.Params().At(i).Type().String())
 		}
 		s += ")"
 	}
 	if sig.Results().Len() == 0 {
 		// keep as-is
 	} else if sig.Results().Len() == 1 {
-		s += " " + emptyInterfaceToAny(sig.Results().At(0).Type().String())
+		s += " " + c.emptyInterfaceToAny(sig.Results().At(0).Type().String())
 	} else {
 		s += " ("
 		for i := 0; i < sig.Results().Len(); i++ {
 			if i > 0 {
 				s += ", "
 			}
-			s += emptyInterfaceToAny(sig.Results().At(i).Type().String())
+			s += c.emptyInterfaceToAny(sig.Results().At(i).Type().String())
 		}
 		s += ")"
 	}
 	return s
 }
 
-func emptyInterfaceToAny(typ string) string {
-	if typ == "interface{}" {
+func (c *compilerContext) emptyInterfaceToAny(typ string) string {
+	if c.GoMinorVersion >= 18 && typ == "interface{}" {
 		return "any"
 	}