env GOPRIVATE='test/main,rsc.io/*' garble build -tags directives exec ./main$exe cmp stderr main.stderr ! binsubstr main$exe 'localName' 'globalConst' 'globalVar' 'globalType' 'valuable information' 'rsc.io' 'remoteIntReturn' 'intReturn' binsubstr main$exe 'magicFunc' [short] stop # no need to verify this with -short go build -tags directives exec ./main$exe cmp stderr main.stderr binsubstr main$exe 'globalVar' # 'globalType' only matches on go < 1.15 ! binsubstr main$exe 'localName' 'globalConst' 'remoteIntReturn' 'intReturn' -- go.mod -- module test/main -- main.go -- package main import ( "encoding/json" "go/ast" "rsc.io/quote" "test/main/sub" ) // This comment contains valuable information. Ensure it's not in the final binary. var V interface{} type T struct { ast.Node *ast.Ident } type EncodingT struct { Foo int } type Embedded int type Embedding struct { Embedded } type embedded int type embedding struct { embedded } // embedded fields whose type is in the universe scope used to crash garble type EmbeddingUniverseScope struct { error int string } func main() { switch V := V.(type) { case int: var _ int = V case nil: println("nil case") } enc, _ := json.Marshal(EncodingT{Foo: 3}) println(string(enc)) scopesTest() println(quote.Go()) sub.Test() sub.TestDirectives() } -- scopes.go -- package main const globalConst = 1 type globalType int var ( globalVar = 1 globalVarTyped globalType = 1 ) func scopesTest() { println(globalVar, globalConst, globalVarTyped) const localNameConst = 1 localNameShort := 4 type localNameType int var ( localNameVar = 5 localNameTypeVar localNameType = 1 ) println(localNameConst, localNameShort, localNameVar, localNameTypeVar, input("input")) } func input(localNameParam string) (localNameReturn string) { return localNameParam } -- sub/names.go -- package sub var someGlobalVar0 = "0" var someGlobalVar1 = "1" var someGlobalVar2 = "2" func Test() { var A, B, C, D, E string noop(A, B, C, D, E) if someGlobalVar0 != "0" || someGlobalVar1 != "1" || someGlobalVar2 != "2"{ panic("name collision detected") } } func noop(...interface{}) {} -- sub/directives.go -- // +build directives package sub import ( _ "unsafe" _ "test/main/sub/a" ) //go:linkname remoteIntReturn a.magicFunc func remoteIntReturn() int //go:noinline func TestDirectives() { if remoteIntReturn() != 42 { panic("invalid result") } } -- sub/a/directives.go -- // +build directives package a import _ "unsafe" //go:linkname intReturn a.magicFunc //go:noinline func intReturn() int { return 42 } -- main.stderr -- nil case {"Foo":3} 1 1 1 1 4 5 1 input Don't communicate by sharing memory, share memory by communicating.