runtime: fully implement GOROOT and GODEBUG

builder/build.go

@@ -248,6 +248,9 @@ func Build(pkgName, outpath, tmpdir string, config *compileopts.Config) (BuildRe
 	if err != nil {
 		return BuildResult{}, err
 	}
+	if _, ok := globalValues["runtime"]["godebugDefault"]; !ok {
+		globalValues["runtime"]["godebugDefault"] = lprogram.MainPkg().DefaultGODEBUG
+	}
 	result := BuildResult{
 		ModuleRoot: lprogram.MainPkg().Module.Dir,
 		MainDir:    lprogram.MainPkg().Dir,
@@ -1365,6 +1368,9 @@ func createEmbedObjectFile(data, hexSum, sourceFile, sourceDir, tmpdir string, c
 // needed to convert a program to its final form. Some transformations are not
 // optional and must be run as the compiler expects them to run.
 func optimizeProgram(mod llvm.Module, config *compileopts.Config) error {
+	if err := transform.PrepareRuntimeStartup(mod); err != nil {
+		return err
+	}
 	err := interp.Run(mod, config.Options.InterpTimeout, config.Options.InterpMaxLoopIterations, config.DumpSSA())
 	if err != nil {
 		return err

builder/testdata/binary-size.txt

@@ -17,5 +17,5 @@ pico2           ./testdata/size-os       z    6199   1209  128  5592
 pico2           ./testdata/size-os       2   15290   1014  128  5592
 cortex-m-qemu   ./testdata/size-corpus   z    9891   1301   80  4188
 cortex-m-qemu   ./testdata/size-corpus   2   17466    862   72  4188
-riscv-qemu      ./testdata/size-corpus   z   17508   1028   88 16660
-riscv-qemu      ./testdata/size-corpus   2   25160    744   80 16644
+riscv-qemu      ./testdata/size-corpus   z   17556   1028   88 16660
+riscv-qemu      ./testdata/size-corpus   2   23225    935   80 16644

compiler/compiler.go

@@ -2355,6 +2355,8 @@ func (b *builder) createBuiltin(argTypes []types.Type, argValues []llvm.Value, c
 //
 // This is also where compiler intrinsics are implemented.
 func (b *builder) createFunctionCall(instr *ssa.CallCommon) (llvm.Value, error) {
+	b.markRuntimeFeatureUse(instr)
+
 	// See if this is an intrinsic function that is handled specially.
 	if fn := instr.StaticCallee(); fn != nil {
 		// Direct function call, either to a named or anonymous (directly

compiler/defer.go

@@ -420,6 +420,8 @@ func (b *builder) loadDeferredCallParams(structType llvm.Type, ptr llvm.Value) [
 // createDefer emits a single defer instruction, to be run when this function
 // returns.
 func (b *builder) createDefer(instr *ssa.Defer) {
+	b.markRuntimeFeatureUse(&instr.Call)
+
 	// The pointer to the previous defer struct, which we will replace to
 	// make a linked list.
 	next := b.CreateLoad(b.dataPtrType, b.deferPtr, "defer.next")

compiler/goroutine.go

@@ -14,6 +14,8 @@ import (
 
 // createGo emits code to start a new goroutine.
 func (b *builder) createGo(instr *ssa.Go) {
+	b.markRuntimeFeatureUse(&instr.Call)
+
 	if builtin, ok := instr.Call.Value.(*ssa.Builtin); ok {
 		// We cheat. None of the builtins do any long or blocking operation, so
 		// we might as well run these builtins right away without the program

compiler/runtimefeature.go

@@ -0,0 +1,34 @@
+package compiler
+
+import (
+	"golang.org/x/tools/go/ssa"
+	"tinygo.org/x/go-llvm"
+)
+
+func (b *builder) markRuntimeFeatureUse(call *ssa.CallCommon) {
+	callee := call.StaticCallee()
+	if callee == nil {
+		return
+	}
+
+	var markerName string
+	switch b.getFunctionInfo(callee).linkName {
+	case "runtime.GOROOT":
+		markerName = "tinygo.runtime.feature.goroot"
+	case "(*internal/godebug.Setting).Value":
+		markerName = "tinygo.runtime.feature.godebug"
+	case "internal/godebug.setUpdate":
+		if b.fn.Pkg != nil && b.fn.Pkg.Pkg.Path() == "internal/godebug" {
+			return
+		}
+		markerName = "tinygo.runtime.feature.godebug"
+	default:
+		return
+	}
+
+	marker := b.mod.NamedFunction(markerName)
+	if marker.IsNil() {
+		marker = llvm.AddFunction(b.mod, markerName, llvm.FunctionType(b.ctx.VoidType(), nil, false))
+	}
+	b.CreateCall(marker.GlobalValueType(), marker, nil, "")
+}

loader/loader.go

@@ -54,14 +54,15 @@ type Program struct {
 
 // PackageJSON is a subset of the JSON struct returned from `go list`.
 type PackageJSON struct {
-	Dir        string
-	ImportPath string
-	Name       string
-	ForTest    string
-	Root       string
-	Standard   bool
-	DepOnly    bool
-	Module     struct {
+	Dir            string
+	ImportPath     string
+	Name           string
+	ForTest        string
+	Root           string
+	Standard       bool
+	DepOnly        bool
+	DefaultGODEBUG string
+	Module         struct {
 		Path      string
 		Main      bool
 		Dir       string

runtime_test.go

@@ -13,6 +13,7 @@ import (
 	"github.com/tetratelabs/wazero"
 	"github.com/tetratelabs/wazero/imports/wasi_snapshot_preview1"
 	"github.com/tinygo-org/tinygo/builder"
+	"github.com/tinygo-org/tinygo/goenv"
 )
 
 // TestTimerStopResetRace checks that stopping or resetting a timer while its
@@ -166,3 +167,71 @@ func TestStdin(t *testing.T) {
 	}
 	checkOutput(t, TESTDATA+"/stdin.txt", output.Bytes())
 }
+
+func TestRuntimeGOROOT(t *testing.T) {
+	t.Parallel()
+
+	for _, test := range []struct {
+		name        string
+		environment []string
+		want        string
+	}{
+		{"startup environment", []string{"GOROOT=/startup"}, "/startup"},
+		{"empty startup environment", []string{"GOROOT="}, goenv.Get("GOROOT")},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			options := optionsFromTarget(*testTarget, sema)
+			config, err := builder.NewConfig(&options)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			output := &bytes.Buffer{}
+			_, err = buildAndRun("testdata/runtimegoroot.go", config, output, nil, test.environment, time.Minute, func(cmd *exec.Cmd, _ builder.BuildResult) error {
+				return cmd.Run()
+			})
+			if err != nil {
+				t.Fatal(err)
+			}
+			want := test.want + "\n" + test.want + "\n"
+			if output.String() != want {
+				t.Fatalf("unexpected output:\n%s\nwant:\n%s", output.String(), want)
+			}
+		})
+	}
+}
+
+func TestRuntimeGODEBUG(t *testing.T) {
+	t.Parallel()
+
+	for _, test := range []struct {
+		name        string
+		program     string
+		environment []string
+		want        string
+	}{
+		{"compiled default", "testdata/runtimegodebug.go", nil, "true \"\"\ntrue \"\"\ntrue \"\"\ntrue \"tarinsecurepath=1\"\ntrue \"\"\ntrue \"\"\n"},
+		{"environment override", "testdata/runtimegodebug.go", []string{"GODEBUG=tarinsecurepath=1"}, "true \"tarinsecurepath=1\"\ntrue \"\"\ntrue \"\"\ntrue \"tarinsecurepath=1\"\ntrue \"\"\ntrue \"\"\n"},
+		{"setting compiled default", "testdata/runtimegodebugsetting.go", nil, "true\nfalse\ntrue\ntrue\n"},
+		{"setting environment override", "testdata/runtimegodebugsetting.go", []string{"GODEBUG=tarinsecurepath=1"}, "false\nfalse\ntrue\ntrue\n"},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			options := optionsFromTarget(*testTarget, sema)
+			config, err := builder.NewConfig(&options)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			output := &bytes.Buffer{}
+			_, err = buildAndRun(test.program, config, output, nil, test.environment, time.Minute, func(cmd *exec.Cmd, _ builder.BuildResult) error {
+				return cmd.Run()
+			})
+			if err != nil {
+				t.Fatal(err)
+			}
+			if output.String() != test.want {
+				t.Fatalf("unexpected output:\n%s\nwant:\n%s", output.String(), test.want)
+			}
+		})
+	}
+}

src/runtime/env.go

@@ -10,11 +10,11 @@ func syscallSetenv(key, value string) {
 	keydata := cstring(key)
 	valdata := cstring(value)
 	setenv(&keydata[0], &valdata[0])
-	if key == "GODEBUG" && godebugUpdate != nil {
+	if key == "GODEBUG" && godebugEnvEnabled() {
 		// Starting with Go 1.20, we need to call a callback (set by
 		// internal/godebug) to notify the GODEBUG environment variable has
 		// changed. This is necessary to get archive/zip to pass tests.
-		godebugUpdate(key, value)
+		godebugSetEnv(value)
 	}
 }
 
@@ -25,6 +25,9 @@ func syscallSetenv(key, value string) {
 func syscallUnsetenv(key string) {
 	keydata := cstring(key)
 	unsetenv(&keydata[0])
+	if key == "GODEBUG" && godebugEnvEnabled() {
+		godebugUnsetEnv()
+	}
 }
 
 // Clear the environment.

src/runtime/env_nonhosted.go

@@ -8,15 +8,15 @@ func syscallSetenv(key, value string) {
 	for i, e := range env {
 		if envKey(e) == key {
 			env[i] = entry
-			if key == "GODEBUG" && godebugUpdate != nil {
-				godebugUpdate(key, value)
+			if key == "GODEBUG" && godebugEnvEnabled() {
+				godebugSetEnv(value)
 			}
 			return
 		}
 	}
 	env = append(env, entry)
-	if key == "GODEBUG" && godebugUpdate != nil {
-		godebugUpdate(key, value)
+	if key == "GODEBUG" && godebugEnvEnabled() {
+		godebugSetEnv(value)
 	}
 }
 
@@ -25,12 +25,15 @@ func syscallUnsetenv(key string) {
 	for i, e := range env {
 		if envKey(e) == key {
 			env = append(env[:i], env[i+1:]...)
-			if key == "GODEBUG" && godebugUpdate != nil {
-				godebugUpdate(key, "")
+			if key == "GODEBUG" && godebugEnvEnabled() {
+				godebugUnsetEnv()
 			}
 			return
 		}
 	}
+	if key == "GODEBUG" {
+		godebugUnsetEnv()
+	}
 }
 
 func envKey(entry string) string {

src/runtime/env_startup_libc.go

@@ -0,0 +1,27 @@
+//go:build darwin || windows || wasip1 || (linux && !baremetal && !wasm_unknown && !wasip2 && !nintendoswitch)
+
+package runtime
+
+import "unsafe"
+
+//export getenv
+func libc_getenv(name *byte) *byte
+
+func startupEnv(key string) string {
+	name := make([]byte, len(key)+1)
+	copy(name, key)
+	value := libc_getenv(&name[0])
+	if value == nil {
+		return ""
+	}
+	length := strlen(unsafe.Pointer(value))
+	return string(unsafe.Slice(value, length))
+}
+
+func init() {
+	if gorootEnvEnabled() {
+		if value := startupEnv("GOROOT"); value != "" {
+			goroot = value
+		}
+	}
+}

src/runtime/env_wasip2.go

@@ -8,14 +8,14 @@ package runtime
 
 //go:linkname syscallSetenv syscall.runtimeSetenv
 func syscallSetenv(key, value string) {
-	if key == "GODEBUG" && godebugUpdate != nil {
-		godebugUpdate(key, value)
+	if key == "GODEBUG" && godebugEnvEnabled() {
+		godebugSetEnv(value)
 	}
 }
 
 //go:linkname syscallUnsetenv syscall.runtimeUnsetenv
 func syscallUnsetenv(key string) {
-	if key == "GODEBUG" && godebugUpdate != nil {
-		godebugUpdate(key, "")
+	if key == "GODEBUG" && godebugEnvEnabled() {
+		godebugUnsetEnv()
 	}
 }

src/runtime/godebug_startup_libc.go

@@ -0,0 +1,9 @@
+//go:build (linux && !baremetal && !wasm_unknown && !wasip2 && !nintendoswitch) || darwin || windows
+
+package runtime
+
+func init() {
+	if godebugEnvEnabled() {
+		godebugStartup = startupEnv("GODEBUG")
+	}
+}

src/runtime/nonhosted.go

@@ -54,3 +54,23 @@ func init() {
 		env = append(env, s[start:])
 	}
 }
+
+func init() {
+	if gorootEnvEnabled() {
+		if value := startupEnv("GOROOT"); value != "" {
+			goroot = value
+		}
+	}
+	if godebugEnvEnabled() {
+		godebugStartup = startupEnv("GODEBUG")
+	}
+}
+
+func startupEnv(key string) string {
+	for _, entry := range env {
+		if len(entry) > len(key) && entry[:len(key)] == key && entry[len(key)] == '=' {
+			return entry[len(key)+1:]
+		}
+	}
+	return ""
+}