From 4e88ee103c5c6462f70895a8aa5780de751f289c Mon Sep 17 00:00:00 2001
From: mathetake <takeshi@tetrate.io>
Date: Thu, 17 Sep 2020 22:49:37 +0900
Subject: [PATCH 01/15] initial commit for WASI support

* merge "time" package with wasi build tag
* override syscall package with wasi build tag
* create runtime_wasm_{js,wasi}.go files
* create syscall_wasi.go file
* create time/zoneinfo_wasi.go file as the replacement of zoneinfo_js.go
* add targets/wasi.json target
---
 loader/goroot.go                 |  22 +++++-
 loader/loader.go                 |   2 +-
 src/runtime/runtime_wasm.go      |  54 --------------
 src/runtime/runtime_wasm_js.go   |  59 +++++++++++++++
 src/runtime/runtime_wasm_wasi.go |  41 +++++++++++
 src/syscall/syscall_wasi.go      | 123 +++++++++++++++++++++++++++++++
 src/syscall/tables_baremetal.go  |   2 +-
 src/time/zoneinfo_wasi.go        |  11 +++
 targets/wasi.json                |  22 ++++++
 9 files changed, 278 insertions(+), 58 deletions(-)
 create mode 100644 src/runtime/runtime_wasm_js.go
 create mode 100644 src/runtime/runtime_wasm_wasi.go
 create mode 100644 src/syscall/syscall_wasi.go
 create mode 100644 src/time/zoneinfo_wasi.go
 create mode 100644 targets/wasi.json

diff --git a/loader/goroot.go b/loader/goroot.go
index 9648550719..aed7e4e466 100644
--- a/loader/goroot.go
+++ b/loader/goroot.go
@@ -15,6 +15,7 @@ import (
 	"path"
 	"path/filepath"
 	"runtime"
+	"strings"
 	"sync"
 
 	"github.com/tinygo-org/tinygo/compileopts"
@@ -164,6 +165,17 @@ func mergeDirectory(goroot, tinygoroot, tmpgoroot, importPath string, overrides
 			return err
 		}
 		for _, e := range gorootEntries {
+			if isMergeTargetEntry(importPath, e.Name()) {
+				// In this case, we have files both from TinyGo and Go.
+				// As of now, this is only for WASI to have *_wasi.go files as replacements for *_js.go files
+				newname := filepath.Join(tmpgoroot, "src", importPath, e.Name())
+				oldname := filepath.Join(goroot, "src", importPath, e.Name())
+				err := symlink(oldname, newname)
+				if err != nil {
+					return err
+				}
+				continue
+			}
 			if !e.IsDir() {
 				// Don't merge in files from Go. Otherwise we'd end up with a
 				// weird syscall package with files from both roots.
@@ -185,11 +197,16 @@ func mergeDirectory(goroot, tinygoroot, tmpgoroot, importPath string, overrides
 	return nil
 }
 
+func isMergeTargetEntry(importPath string, name string) bool {
+	// TODO: add crypto/rand
+	return importPath == "time" && !strings.HasSuffix(name, "_js.go")
+}
+
 // needsSyscallPackage returns whether the syscall package should be overriden
 // with the TinyGo version. This is the case on some targets.
 func needsSyscallPackage(buildTags []string) bool {
 	for _, tag := range buildTags {
-		if tag == "baremetal" || tag == "darwin" || tag == "nintendoswitch" {
+		if tag == "baremetal" || tag == "darwin" || tag == "nintendoswitch" || tag == "wasi" {
 			return true
 		}
 	}
@@ -212,7 +229,8 @@ func pathsToOverride(needsSyscallPackage bool) map[string]bool {
 		"reflect/":              false,
 		"runtime/":              false,
 		"sync/":                 true,
-		"testing/":              true,
+		"time/":                 true,
+		"testing/":              false,
 	}
 	if needsSyscallPackage {
 		paths["syscall/"] = true // include syscall/js
diff --git a/loader/loader.go b/loader/loader.go
index 847acc2584..6200cc574b 100644
--- a/loader/loader.go
+++ b/loader/loader.go
@@ -166,7 +166,6 @@ func Load(config *compileopts.Config, inputPkgs []string, clangHeaders string, t
 					Err:         err,
 				}
 			}
-			return nil, err
 		}
 		if config.TestConfig.CompileTestBinary {
 			// When creating a test binary, `go list` will list two or three
@@ -230,6 +229,7 @@ func (p *Program) getOriginalPath(path string) string {
 			}
 			maybeInTinyGoRoot = true
 		}
+
 		if maybeInTinyGoRoot {
 			tinygoPath := filepath.Join(goenv.Get("TINYGOROOT"), "src", relpath)
 			if _, err := os.Stat(tinygoPath); err == nil {
diff --git a/src/runtime/runtime_wasm.go b/src/runtime/runtime_wasm.go
index aaf95d7846..4bd9c7b3c8 100644
--- a/src/runtime/runtime_wasm.go
+++ b/src/runtime/runtime_wasm.go
@@ -4,8 +4,6 @@ package runtime
 
 import "unsafe"
 
-type timeUnit float64 // time in milliseconds, just like Date.now() in JavaScript
-
 // Implements __wasi_ciovec_t and __wasi_iovec_t.
 type wasiIOVec struct {
 	buf    unsafe.Pointer
@@ -18,15 +16,6 @@ func fd_write(id uint32, iovs *wasiIOVec, iovs_len uint, nwritten *uint) (errno
 
 func postinit() {}
 
-//export _start
-func _start() {
-	// These need to be initialized early so that the heap can be initialized.
-	heapStart = uintptr(unsafe.Pointer(&heapStartSymbol))
-	heapEnd = uintptr(wasm_memory_size(0) * wasmPageSize)
-
-	run()
-}
-
 // Using global variables to avoid heap allocation.
 var (
 	putcharBuf   = byte(0)
@@ -44,49 +33,6 @@ func putchar(c byte) {
 	fd_write(stdout, &putcharIOVec, 1, &nwritten)
 }
 
-var handleEvent func()
-
-//go:linkname setEventHandler syscall/js.setEventHandler
-func setEventHandler(fn func()) {
-	handleEvent = fn
-}
-
-//export resume
-func resume() {
-	go func() {
-		handleEvent()
-	}()
-	scheduler()
-}
-
-//export go_scheduler
-func go_scheduler() {
-	scheduler()
-}
-
-const asyncScheduler = true
-
-func ticksToNanoseconds(ticks timeUnit) int64 {
-	// The JavaScript API works in float64 milliseconds, so convert to
-	// nanoseconds first before converting to a timeUnit (which is a float64),
-	// to avoid precision loss.
-	return int64(ticks * 1e6)
-}
-
-func nanosecondsToTicks(ns int64) timeUnit {
-	// The JavaScript API works in float64 milliseconds, so convert to timeUnit
-	// (which is a float64) first before dividing, to avoid precision loss.
-	return timeUnit(ns) / 1e6
-}
-
-// This function is called by the scheduler.
-// Schedule a call to runtime.scheduler, do not actually sleep.
-//export runtime.sleepTicks
-func sleepTicks(d timeUnit)
-
-//export runtime.ticks
-func ticks() timeUnit
-
 // Abort executes the wasm 'unreachable' instruction.
 func abort() {
 	trap()
diff --git a/src/runtime/runtime_wasm_js.go b/src/runtime/runtime_wasm_js.go
new file mode 100644
index 0000000000..ea1cc6e41d
--- /dev/null
+++ b/src/runtime/runtime_wasm_js.go
@@ -0,0 +1,59 @@
+// +build wasm,!wasi
+
+package runtime
+
+import "unsafe"
+
+type timeUnit float64 // time in milliseconds, just like Date.now() in JavaScript
+
+//export _start
+func _start() {
+	// These need to be initialized early so that the heap can be initialized.
+	heapStart = uintptr(unsafe.Pointer(&heapStartSymbol))
+	heapEnd = uintptr(wasm_memory_size(0) * wasmPageSize)
+
+	run()
+}
+
+var handleEvent func()
+
+//go:linkname setEventHandler syscall/js.setEventHandler
+func setEventHandler(fn func()) {
+	handleEvent = fn
+}
+
+//export resume
+func resume() {
+	go func() {
+		handleEvent()
+	}()
+	scheduler()
+}
+
+//export go_scheduler
+func go_scheduler() {
+	scheduler()
+}
+
+const asyncScheduler = true
+
+func ticksToNanoseconds(ticks timeUnit) int64 {
+	// The JavaScript API works in float64 milliseconds, so convert to
+	// nanoseconds first before converting to a timeUnit (which is a float64),
+	// to avoid precision loss.
+	return int64(ticks * 1e6)
+}
+
+func nanosecondsToTicks(ns int64) timeUnit {
+	// The JavaScript API works in float64 milliseconds, so convert to timeUnit
+	// (which is a float64) first before dividing, to avoid precision loss.
+	return timeUnit(ns) / 1e6
+}
+
+// This function is called by the scheduler.
+// Schedule a call to runtime.scheduler, do not actually sleep.
+//export runtime.sleepTicks
+func sleepTicks(d timeUnit)
+
+//export runtime.ticks
+func ticks() timeUnit
diff --git a/src/runtime/runtime_wasm_wasi.go b/src/runtime/runtime_wasm_wasi.go
new file mode 100644
index 0000000000..a7798654ba
--- /dev/null
+++ b/src/runtime/runtime_wasm_wasi.go
@@ -0,0 +1,41 @@
+// +build wasm,wasi
+
+package runtime
+
+import "unsafe"
+
+type timeUnit float64
+
+//export _start
+func _start() {
+	// These need to be initialized early so that the heap can be initialized.
+	heapStart = uintptr(unsafe.Pointer(&heapStartSymbol))
+	heapEnd = uintptr(wasm_memory_size(0) * wasmPageSize)
+
+	run()
+}
+
+const asyncScheduler = true
+
+func ticksToNanoseconds(ticks timeUnit) int64 {
+	return int64(ticks)
+}
+
+func nanosecondsToTicks(ns int64) timeUnit {
+	return timeUnit(ns)
+}
+
+// This function is called by the scheduler.
+// Schedule a call to runtime.scheduler, do not actually sleep.
+//export runtime.sleepTicks
+func sleepTicks(d timeUnit)
+
+//go:wasm-module wasi_unstable
+//export clock_time_get
+func clock_time_get(id uint32, precision uint64, timePtr *uint64) (errno uint)
+
+func ticks() timeUnit {
+	var time uint64
+	clock_time_get(0, 100, &time)
+	return timeUnit(time)
+}
diff --git a/src/syscall/syscall_wasi.go b/src/syscall/syscall_wasi.go
new file mode 100644
index 0000000000..ad6dbb1111
--- /dev/null
+++ b/src/syscall/syscall_wasi.go
@@ -0,0 +1,123 @@
+// +build wasi
+
+package syscall
+
+// Most code here has been copied from the Go sources:
+//   https://github.com/golang/go/blob/go1.12/src/syscall/syscall_js.go
+// It has the following copyright note:
+//
+//     Copyright 2018 The Go Authors. All rights reserved.
+//     Use of this source code is governed by a BSD-style
+//     license that can be found in the LICENSE file.
+
+// A Signal is a number describing a process signal.
+// It implements the os.Signal interface.
+type Signal int
+
+const (
+	_ Signal = iota
+	SIGCHLD
+	SIGINT
+	SIGKILL
+	SIGTRAP
+	SIGQUIT
+	SIGTERM
+)
+
+// File system
+
+const (
+	Stdin  = 0
+	Stdout = 1
+	Stderr = 2
+)
+
+const (
+	O_RDONLY = 0
+	O_WRONLY = 1
+	O_RDWR   = 2
+
+	O_CREAT  = 0100
+	O_CREATE = O_CREAT
+	O_TRUNC  = 01000
+	O_APPEND = 02000
+	O_EXCL   = 0200
+	O_SYNC   = 010000
+
+	O_CLOEXEC = 0
+)
+
+func Getenv(key string) (value string, found bool) {
+	return "", false // stub
+}
+
+func Open(path string, mode int, perm uint32) (fd int, err error) {
+	return 0, ENOSYS
+}
+
+func Read(fd int, p []byte) (n int, err error) {
+	return 0, ENOSYS
+}
+
+func Seek(fd int, offset int64, whence int) (off int64, err error) {
+	return 0, ENOSYS
+}
+
+func Close(fd int) (err error) {
+	return ENOSYS
+}
+
+// Processes
+
+type WaitStatus uint32
+
+func (w WaitStatus) Exited() bool       { return false }
+func (w WaitStatus) ExitStatus() int    { return 0 }
+func (w WaitStatus) Signaled() bool     { return false }
+func (w WaitStatus) Signal() Signal     { return 0 }
+func (w WaitStatus) CoreDump() bool     { return false }
+func (w WaitStatus) Stopped() bool      { return false }
+func (w WaitStatus) Continued() bool    { return false }
+func (w WaitStatus) StopSignal() Signal { return 0 }
+func (w WaitStatus) TrapCause() int     { return 0 }
+
+// XXX made up
+type Rusage struct {
+	Utime Timeval
+	Stime Timeval
+}
+
+// XXX made up
+type ProcAttr struct {
+	Dir   string
+	Env   []string
+	Files []uintptr
+	Sys   *SysProcAttr
+}
+
+type SysProcAttr struct {
+}
+
+func Getegid() int                      { return 1 }
+func Geteuid() int                      { return 1 }
+func Getgid() int                       { return 1 }
+func Getgroups() ([]int, error)         { return []int{1}, nil }
+func Getppid() int                      { return 2 }
+func Getpid() int                       { return 3 }
+func Gettimeofday(tv *Timeval) error    { return ENOSYS }
+func Getuid() int                       { return 1 }
+func Kill(pid int, signum Signal) error { return ENOSYS }
+func Sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) {
+	return 0, ENOSYS
+}
+func StartProcess(argv0 string, argv []string, attr *ProcAttr) (pid int, handle uintptr, err error) {
+	return 0, 0, ENOSYS
+}
+func Wait4(pid int, wstatus *WaitStatus, options int, rusage *Rusage) (wpid int, err error) {
+	return 0, ENOSYS
+}
+
+type Timeval struct {
+	Sec  int64
+	Usec int64
+}
diff --git a/src/syscall/tables_baremetal.go b/src/syscall/tables_baremetal.go
index 47a536bffd..9677d77a09 100644
--- a/src/syscall/tables_baremetal.go
+++ b/src/syscall/tables_baremetal.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build baremetal nintendoswitch
+// +build baremetal nintendoswitch wasi
 
 package syscall
 
diff --git a/src/time/zoneinfo_wasi.go b/src/time/zoneinfo_wasi.go
new file mode 100644
index 0000000000..5dc771522d
--- /dev/null
+++ b/src/time/zoneinfo_wasi.go
@@ -0,0 +1,11 @@
+// +build wasi
+
+// should be replaced with original time/zoneinfo_js.go
+
+package time
+
+var zoneSources []string // TODO:
+
+func initLocal() {
+	// TODO:
+}
diff --git a/targets/wasi.json b/targets/wasi.json
new file mode 100644
index 0000000000..09ab606d72
--- /dev/null
+++ b/targets/wasi.json
@@ -0,0 +1,22 @@
+{
+	"llvm-target":   "wasm32--wasi",
+	"build-tags":    ["js", "wasm", "wasi"],
+	"goos":          "js",
+	"goarch":        "wasm",
+	"compiler":      "clang",
+	"linker":        "wasm-ld",
+	"cflags": [
+		"--target=wasm32--wasi",
+		"--sysroot={root}/lib/wasi-libc/sysroot",
+		"-Oz"
+	],
+	"ldflags": [
+		"--allow-undefined",
+		"--no-threads",
+		"--stack-first",
+		"--export-dynamic",
+		"--no-demangle",
+		"{root}/lib/wasi-libc/sysroot/lib/wasm32-wasi/libc.a"
+	],
+	"emulator":      ["node", "targets/wasm_exec.js"]
+}

From c711c445862eda07d001b015927d287605a15391 Mon Sep 17 00:00:00 2001
From: mathetake <takeshi@tetrate.io>
Date: Thu, 17 Sep 2020 22:54:17 +0900
Subject: [PATCH 02/15] set visbility hidden for runtime extern variables

Accodring to the WASI docs (https://github.com/WebAssembly/WASI/blob/master/design/application-abi.md#current-unstable-abi),
none of exports of WASI executable(Command) should no be accessed.

v0.19.0 of bytecodealliance/wasmetime, which is often refered to as the reference implementation of WASI,
does not accept any exports except functions and the only limited variables like "table", "memory".
---
 transform/gc.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/transform/gc.go b/transform/gc.go
index 9329644522..d8258a01ba 100644
--- a/transform/gc.go
+++ b/transform/gc.go
@@ -96,6 +96,7 @@ func MakeGCStackSlots(mod llvm.Module) bool {
 	}
 	stackChainStartType := stackChainStart.Type().ElementType()
 	stackChainStart.SetInitializer(llvm.ConstNull(stackChainStartType))
+	stackChainStart.SetVisibility(llvm.HiddenVisibility)
 
 	// Iterate until runtime.trackPointer has no uses left.
 	for use := trackPointer.FirstUse(); !use.IsNil(); use = trackPointer.FirstUse() {
@@ -333,12 +334,14 @@ func AddGlobalsBitmap(mod llvm.Module) bool {
 	// Update trackedGlobalsStart, which points to the globals bundle.
 	trackedGlobalsStart := llvm.ConstPtrToInt(globalsBundle, uintptrType)
 	mod.NamedGlobal("runtime.trackedGlobalsStart").SetInitializer(trackedGlobalsStart)
+	mod.NamedGlobal("runtime.trackedGlobalsStart").SetVisibility(llvm.HiddenVisibility)
 
 	// Update trackedGlobalsLength, which contains the length (in words) of the
 	// globals bundle.
 	alignment := targetData.PrefTypeAlignment(llvm.PointerType(ctx.Int8Type(), 0))
 	trackedGlobalsLength := llvm.ConstInt(uintptrType, targetData.TypeAllocSize(globalsBundleType)/uint64(alignment), false)
 	mod.NamedGlobal("runtime.trackedGlobalsLength").SetInitializer(trackedGlobalsLength)
+	mod.NamedGlobal("runtime.trackedGlobalsLength").SetVisibility(llvm.HiddenVisibility)
 
 	// Create a bitmap (a new global) that stores for each word in the globals
 	// bundle whether it contains a pointer. This allows globals to be scanned
@@ -357,6 +360,7 @@ func AddGlobalsBitmap(mod llvm.Module) bool {
 	bitmapOld.ReplaceAllUsesWith(llvm.ConstBitCast(bitmapNew, bitmapOld.Type()))
 	bitmapNew.SetInitializer(bitmapArray)
 	bitmapNew.SetName("runtime.trackedGlobalsBitmap")
+	bitmapNew.SetVisibility(llvm.HiddenVisibility)
 
 	return true // the IR was changed
 }

From d400858bb9fa643e6f9831aad07f64abb880f40b Mon Sep 17 00:00:00 2001
From: mathetake <takeshi@tetrate.io>
Date: Thu, 17 Sep 2020 23:17:54 +0900
Subject: [PATCH 03/15] merge syscall_{baremetal,wasi}.go

---
 loader/goroot.go                 |   2 +-
 src/syscall/syscall_baremetal.go |   2 +-
 src/syscall/syscall_wasi.go      | 123 -------------------------------
 src/time/zoneinfo_wasi.go        |   2 +
 4 files changed, 4 insertions(+), 125 deletions(-)
 delete mode 100644 src/syscall/syscall_wasi.go

diff --git a/loader/goroot.go b/loader/goroot.go
index aed7e4e466..fb0d2cc6b8 100644
--- a/loader/goroot.go
+++ b/loader/goroot.go
@@ -230,7 +230,7 @@ func pathsToOverride(needsSyscallPackage bool) map[string]bool {
 		"runtime/":              false,
 		"sync/":                 true,
 		"time/":                 true,
-		"testing/":              false,
+		"testing/":              true,
 	}
 	if needsSyscallPackage {
 		paths["syscall/"] = true // include syscall/js
diff --git a/src/syscall/syscall_baremetal.go b/src/syscall/syscall_baremetal.go
index 28fa39ba85..2331101ba3 100644
--- a/src/syscall/syscall_baremetal.go
+++ b/src/syscall/syscall_baremetal.go
@@ -1,4 +1,4 @@
-// +build baremetal
+// +build baremetal wasi
 
 package syscall
 
diff --git a/src/syscall/syscall_wasi.go b/src/syscall/syscall_wasi.go
deleted file mode 100644
index ad6dbb1111..0000000000
--- a/src/syscall/syscall_wasi.go
+++ /dev/null
@@ -1,123 +0,0 @@
-// +build wasi
-
-package syscall
-
-// Most code here has been copied from the Go sources:
-//   https://github.com/golang/go/blob/go1.12/src/syscall/syscall_js.go
-// It has the following copyright note:
-//
-//     Copyright 2018 The Go Authors. All rights reserved.
-//     Use of this source code is governed by a BSD-style
-//     license that can be found in the LICENSE file.
-
-// A Signal is a number describing a process signal.
-// It implements the os.Signal interface.
-type Signal int
-
-const (
-	_ Signal = iota
-	SIGCHLD
-	SIGINT
-	SIGKILL
-	SIGTRAP
-	SIGQUIT
-	SIGTERM
-)
-
-// File system
-
-const (
-	Stdin  = 0
-	Stdout = 1
-	Stderr = 2
-)
-
-const (
-	O_RDONLY = 0
-	O_WRONLY = 1
-	O_RDWR   = 2
-
-	O_CREAT  = 0100
-	O_CREATE = O_CREAT
-	O_TRUNC  = 01000
-	O_APPEND = 02000
-	O_EXCL   = 0200
-	O_SYNC   = 010000
-
-	O_CLOEXEC = 0
-)
-
-func Getenv(key string) (value string, found bool) {
-	return "", false // stub
-}
-
-func Open(path string, mode int, perm uint32) (fd int, err error) {
-	return 0, ENOSYS
-}
-
-func Read(fd int, p []byte) (n int, err error) {
-	return 0, ENOSYS
-}
-
-func Seek(fd int, offset int64, whence int) (off int64, err error) {
-	return 0, ENOSYS
-}
-
-func Close(fd int) (err error) {
-	return ENOSYS
-}
-
-// Processes
-
-type WaitStatus uint32
-
-func (w WaitStatus) Exited() bool       { return false }
-func (w WaitStatus) ExitStatus() int    { return 0 }
-func (w WaitStatus) Signaled() bool     { return false }
-func (w WaitStatus) Signal() Signal     { return 0 }
-func (w WaitStatus) CoreDump() bool     { return false }
-func (w WaitStatus) Stopped() bool      { return false }
-func (w WaitStatus) Continued() bool    { return false }
-func (w WaitStatus) StopSignal() Signal { return 0 }
-func (w WaitStatus) TrapCause() int     { return 0 }
-
-// XXX made up
-type Rusage struct {
-	Utime Timeval
-	Stime Timeval
-}
-
-// XXX made up
-type ProcAttr struct {
-	Dir   string
-	Env   []string
-	Files []uintptr
-	Sys   *SysProcAttr
-}
-
-type SysProcAttr struct {
-}
-
-func Getegid() int                      { return 1 }
-func Geteuid() int                      { return 1 }
-func Getgid() int                       { return 1 }
-func Getgroups() ([]int, error)         { return []int{1}, nil }
-func Getppid() int                      { return 2 }
-func Getpid() int                       { return 3 }
-func Gettimeofday(tv *Timeval) error    { return ENOSYS }
-func Getuid() int                       { return 1 }
-func Kill(pid int, signum Signal) error { return ENOSYS }
-func Sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) {
-	return 0, ENOSYS
-}
-func StartProcess(argv0 string, argv []string, attr *ProcAttr) (pid int, handle uintptr, err error) {
-	return 0, 0, ENOSYS
-}
-func Wait4(pid int, wstatus *WaitStatus, options int, rusage *Rusage) (wpid int, err error) {
-	return 0, ENOSYS
-}
-
-type Timeval struct {
-	Sec  int64
-	Usec int64
-}
diff --git a/src/time/zoneinfo_wasi.go b/src/time/zoneinfo_wasi.go
index 5dc771522d..ce3f8786b2 100644
--- a/src/time/zoneinfo_wasi.go
+++ b/src/time/zoneinfo_wasi.go
@@ -4,6 +4,8 @@
 
 package time
 
+// TODO: https://github.com/WebAssembly/WASI/issues/25
+
 var zoneSources []string // TODO:
 
 func initLocal() {

From cacb682d3f758f550b95a240989309e98e3a77f0 Mon Sep 17 00:00:00 2001
From: mathetake <takeshi@tetrate.io>
Date: Thu, 17 Sep 2020 23:33:32 +0900
Subject: [PATCH 04/15] fix js target build

---
 loader/goroot.go | 23 ++++++++++++++++++++---
 loader/loader.go |  5 ++++-
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/loader/goroot.go b/loader/goroot.go
index fb0d2cc6b8..4b43fe7b84 100644
--- a/loader/goroot.go
+++ b/loader/goroot.go
@@ -89,7 +89,10 @@ func GetCachedGoroot(config *compileopts.Config) (string, error) {
 			return "", err
 		}
 	}
-	err = mergeDirectory(goroot, tinygoroot, tmpgoroot, "", pathsToOverride(needsSyscallPackage(config.BuildTags())))
+	err = mergeDirectory(goroot, tinygoroot, tmpgoroot, "", pathsToOverride(
+		needsSyscallPackage(config.BuildTags()),
+		needsTimePackage(config.BuildTags()),
+	))
 	if err != nil {
 		return "", err
 	}
@@ -213,9 +216,20 @@ func needsSyscallPackage(buildTags []string) bool {
 	return false
 }
 
+// needsTimePackage returns whether the time package should be merged
+// with the TinyGo version. This is the case on some targets.
+func needsTimePackage(buildTags []string) bool {
+	for _, tag := range buildTags {
+		if tag == "wasi" {
+			return true
+		}
+	}
+	return false
+}
+
 // The boolean indicates whether to merge the subdirs. True means merge, false
 // means use the TinyGo version.
-func pathsToOverride(needsSyscallPackage bool) map[string]bool {
+func pathsToOverride(needsSyscallPackage, needsTimePackage bool) map[string]bool {
 	paths := map[string]bool{
 		"/":                     true,
 		"device/":               false,
@@ -229,12 +243,15 @@ func pathsToOverride(needsSyscallPackage bool) map[string]bool {
 		"reflect/":              false,
 		"runtime/":              false,
 		"sync/":                 true,
-		"time/":                 true,
 		"testing/":              true,
 	}
 	if needsSyscallPackage {
 		paths["syscall/"] = true // include syscall/js
 	}
+
+	if needsTimePackage {
+		paths["time/"] = true
+	}
 	return paths
 }
 
diff --git a/loader/loader.go b/loader/loader.go
index 6200cc574b..159fa8a195 100644
--- a/loader/loader.go
+++ b/loader/loader.go
@@ -223,7 +223,10 @@ func (p *Program) getOriginalPath(path string) string {
 			originalPath = realgorootPath
 		}
 		maybeInTinyGoRoot := false
-		for prefix := range pathsToOverride(needsSyscallPackage(p.config.BuildTags())) {
+		for prefix := range pathsToOverride(
+			needsSyscallPackage(p.config.BuildTags()),
+			needsTimePackage(p.config.BuildTags()),
+		) {
 			if !strings.HasPrefix(relpath, prefix) {
 				continue
 			}

From c6b77306353af68483b24956a3122e7d283ce84e Mon Sep 17 00:00:00 2001
From: mathetake <takeshi@tetrate.io>
Date: Sat, 19 Sep 2020 11:12:47 +0900
Subject: [PATCH 05/15] mv wasi functions to syscall/wasi && implement
 sleepTicks

---
 src/runtime/runtime_wasm.go      | 22 +++++--------
 src/runtime/runtime_wasm_wasi.go | 52 ++++++++++++++++++++----------
 src/syscall/wasi/clock.go        |  7 ++++
 src/syscall/wasi/common.go       | 15 +++++++++
 src/syscall/wasi/poll_oneoff.go  | 55 ++++++++++++++++++++++++++++++++
 5 files changed, 121 insertions(+), 30 deletions(-)
 create mode 100644 src/syscall/wasi/clock.go
 create mode 100644 src/syscall/wasi/common.go
 create mode 100644 src/syscall/wasi/poll_oneoff.go

diff --git a/src/runtime/runtime_wasm.go b/src/runtime/runtime_wasm.go
index 4bd9c7b3c8..8a9fad424c 100644
--- a/src/runtime/runtime_wasm.go
+++ b/src/runtime/runtime_wasm.go
@@ -2,26 +2,20 @@
 
 package runtime
 
-import "unsafe"
+import (
+	"unsafe"
 
-// Implements __wasi_ciovec_t and __wasi_iovec_t.
-type wasiIOVec struct {
-	buf    unsafe.Pointer
-	bufLen uint
-}
-
-//go:wasm-module wasi_unstable
-//export fd_write
-func fd_write(id uint32, iovs *wasiIOVec, iovs_len uint, nwritten *uint) (errno uint)
+	"github.com/tinygo-org/tinygo/src/syscall/wasi"
+)
 
 func postinit() {}
 
 // Using global variables to avoid heap allocation.
 var (
 	putcharBuf   = byte(0)
-	putcharIOVec = wasiIOVec{
-		buf:    unsafe.Pointer(&putcharBuf),
-		bufLen: 1,
+	putcharIOVec = wasi.IOVec{
+		Buf:    unsafe.Pointer(&putcharBuf),
+		BufLen: 1,
 	}
 )
 
@@ -30,7 +24,7 @@ func putchar(c byte) {
 	const stdout = 1
 	var nwritten uint
 	putcharBuf = c
-	fd_write(stdout, &putcharIOVec, 1, &nwritten)
+	wasi.Fd_write(stdout, &putcharIOVec, 1, &nwritten)
 }
 
 // Abort executes the wasm 'unreachable' instruction.
diff --git a/src/runtime/runtime_wasm_wasi.go b/src/runtime/runtime_wasm_wasi.go
index a7798654ba..cfe8af1bb4 100644
--- a/src/runtime/runtime_wasm_wasi.go
+++ b/src/runtime/runtime_wasm_wasi.go
@@ -2,21 +2,22 @@
 
 package runtime
 
-import "unsafe"
+import (
+	"unsafe"
 
-type timeUnit float64
+	"github.com/tinygo-org/tinygo/src/syscall/wasi"
+)
+
+type timeUnit int64
 
 //export _start
 func _start() {
 	// These need to be initialized early so that the heap can be initialized.
 	heapStart = uintptr(unsafe.Pointer(&heapStartSymbol))
 	heapEnd = uintptr(wasm_memory_size(0) * wasmPageSize)
-
 	run()
 }
 
-const asyncScheduler = true
-
 func ticksToNanoseconds(ticks timeUnit) int64 {
 	return int64(ticks)
 }
@@ -25,17 +26,36 @@ func nanosecondsToTicks(ns int64) timeUnit {
 	return timeUnit(ns)
 }
 
-// This function is called by the scheduler.
-// Schedule a call to runtime.scheduler, do not actually sleep.
-//export runtime.sleepTicks
-func sleepTicks(d timeUnit)
-
-//go:wasm-module wasi_unstable
-//export clock_time_get
-func clock_time_get(id uint32, precision uint64, timePtr *uint64) (errno uint)
+const (
+	asyncScheduler           = false
+	timePrecisionNanoseconds = 1000 // TODO: how can we determine the appropriate `precision`?
+)
+
+var (
+	sleepTicksSubscription = wasi.Subscription_t{
+		UserData: 0,
+		U: wasi.Subscription_u_t{
+			Tag: wasi.Eventtype_t_clock,
+			U: wasi.Subscription_clock_t{
+				UserData:  0,
+				ID:        0,
+				Timeout:   0,
+				Precision: timePrecisionNanoseconds,
+				Flags:     0,
+			},
+		},
+	}
+	sleepTicksResult  = wasi.Event_t{}
+	sleepTicksNEvents uint32
+)
+
+func sleepTicks(d timeUnit) {
+	sleepTicksSubscription.U.U.Timeout = int64(d)
+	wasi.Poll_oneoff(&sleepTicksSubscription, &sleepTicksResult, 1, &sleepTicksNEvents)
+}
 
 func ticks() timeUnit {
-	var time uint64
-	clock_time_get(0, 100, &time)
-	return timeUnit(time)
+	var nano int64
+	wasi.Clock_time_get(0, timePrecisionNanoseconds, &nano)
+	return timeUnit(nano)
 }
diff --git a/src/syscall/wasi/clock.go b/src/syscall/wasi/clock.go
new file mode 100644
index 0000000000..ebb504f3b7
--- /dev/null
+++ b/src/syscall/wasi/clock.go
@@ -0,0 +1,7 @@
+// +build wasm,wasi
+
+package wasi
+
+//go:wasm-module wasi_unstable
+//export clock_time_get
+func Clock_time_get(clockid uint32, precision uint64, time *int64) (errno uint16)
diff --git a/src/syscall/wasi/common.go b/src/syscall/wasi/common.go
new file mode 100644
index 0000000000..1c94d7dfda
--- /dev/null
+++ b/src/syscall/wasi/common.go
@@ -0,0 +1,15 @@
+// +build wasm
+
+package wasi
+
+import "unsafe"
+
+// Implements __wasi_ciovec_t and __wasi_iovec_t.
+type IOVec struct {
+	Buf    unsafe.Pointer
+	BufLen uint
+}
+
+//go:wasm-module wasi_unstable
+//export fd_write
+func Fd_write(id uint32, iovs *IOVec, iovs_len uint, nwritten *uint) (errno uint)
diff --git a/src/syscall/wasi/poll_oneoff.go b/src/syscall/wasi/poll_oneoff.go
new file mode 100644
index 0000000000..c0544b8668
--- /dev/null
+++ b/src/syscall/wasi/poll_oneoff.go
@@ -0,0 +1,55 @@
+// +build wasm,wasi
+
+package wasi
+
+//go:wasm-module wasi_unstable
+//export poll_oneoff
+func Poll_oneoff(in *Subscription_t, out *Event_t, nsubscriptions uint32, nevents *uint32) (errno uint16)
+
+type Eventtype_t = uint8
+
+const (
+	Eventtype_t_clock Eventtype_t = 0
+	// TODO: __wasi_eventtype_t_fd_read  __wasi_eventtype_t = 1
+	// TODO: __wasi_eventtype_t_fd_write __wasi_eventtype_t = 2
+)
+
+type (
+	// https://github.com/wasmerio/wasmer/blob/1.0.0-alpha3/lib/wasi/src/syscalls/types.rs#L584-L588
+	Subscription_t struct {
+		UserData uint64
+		U        Subscription_u_t
+	}
+
+	Subscription_u_t struct {
+		Tag Eventtype_t
+
+		// TODO: support fd_read/fd_write event
+		U Subscription_clock_t
+	}
+
+	// https://github.com/wasmerio/wasmer/blob/1.0.0-alpha3/lib/wasi/src/syscalls/types.rs#L711-L718
+	Subscription_clock_t struct {
+		UserData  uint64
+		ID        uint32
+		Timeout   int64
+		Precision int64
+		Flags     uint16
+	}
+)
+
+type (
+	// https://github.com/wasmerio/wasmer/blob/1.0.0-alpha3/lib/wasi/src/syscalls/types.rs#L191-L198
+	Event_t struct {
+		UserData  uint64
+		Errno     uint16
+		EventType Eventtype_t
+
+		// only used for fd_read or fd_write events
+		// TODO: support fd_read/fd_write event
+		_ struct {
+			NBytes uint64
+			Flags  uint16
+		}
+	}
+)

From a4567e178a77dee6f28c3072f670c91354db4823 Mon Sep 17 00:00:00 2001
From: mathetake <takeshi@tetrate.io>
Date: Sat, 19 Sep 2020 12:14:13 +0900
Subject: [PATCH 06/15] WASI: set visibility hidden for globals variables

---
 transform/gc.go        | 23 +++++++++++++++++------
 transform/gc_test.go   |  4 ++--
 transform/optimizer.go | 20 ++++++++++++++++++--
 3 files changed, 37 insertions(+), 10 deletions(-)

diff --git a/transform/gc.go b/transform/gc.go
index d8258a01ba..74109021c2 100644
--- a/transform/gc.go
+++ b/transform/gc.go
@@ -8,9 +8,12 @@ import (
 
 // MakeGCStackSlots converts all calls to runtime.trackPointer to explicit
 // stores to stack slots that are scannable by the GC.
-func MakeGCStackSlots(mod llvm.Module) bool {
+func MakeGCStackSlots(mod llvm.Module, shouldHiveGlobals bool) bool {
 	// Check whether there are allocations at all.
 	alloc := mod.NamedFunction("runtime.alloc")
+	if shouldHiveGlobals {
+		alloc.SetVisibility(llvm.HiddenVisibility)
+	}
 	if alloc.IsNil() {
 		// Nothing to. Make sure all remaining bits and pieces for stack
 		// chains are neutralized.
@@ -85,6 +88,9 @@ func MakeGCStackSlots(mod llvm.Module) bool {
 
 	// Collect some variables used below in the loop.
 	stackChainStart := mod.NamedGlobal("runtime.stackChainStart")
+	if shouldHiveGlobals {
+		stackChainStart.SetVisibility(llvm.HiddenVisibility)
+	}
 	if stackChainStart.IsNil() {
 		// This may be reached in a weird scenario where we call runtime.alloc but the garbage collector is unreachable.
 		// This can be accomplished by allocating 0 bytes.
@@ -96,7 +102,6 @@ func MakeGCStackSlots(mod llvm.Module) bool {
 	}
 	stackChainStartType := stackChainStart.Type().ElementType()
 	stackChainStart.SetInitializer(llvm.ConstNull(stackChainStartType))
-	stackChainStart.SetVisibility(llvm.HiddenVisibility)
 
 	// Iterate until runtime.trackPointer has no uses left.
 	for use := trackPointer.FirstUse(); !use.IsNil(); use = trackPointer.FirstUse() {
@@ -286,7 +291,7 @@ func MakeGCStackSlots(mod llvm.Module) bool {
 // bitmap (bit vector) to locate all the pointers in this large global. This
 // bitmap allows the GC to know in advance where exactly all the pointers live
 // in the large globals bundle, to avoid false positives.
-func AddGlobalsBitmap(mod llvm.Module) bool {
+func AddGlobalsBitmap(mod llvm.Module, shouldHiveGlobals bool) bool {
 	if mod.NamedGlobal("runtime.trackedGlobalsStart").IsNil() {
 		return false // nothing to do: no GC in use
 	}
@@ -334,14 +339,18 @@ func AddGlobalsBitmap(mod llvm.Module) bool {
 	// Update trackedGlobalsStart, which points to the globals bundle.
 	trackedGlobalsStart := llvm.ConstPtrToInt(globalsBundle, uintptrType)
 	mod.NamedGlobal("runtime.trackedGlobalsStart").SetInitializer(trackedGlobalsStart)
-	mod.NamedGlobal("runtime.trackedGlobalsStart").SetVisibility(llvm.HiddenVisibility)
+	if shouldHiveGlobals {
+		mod.NamedGlobal("runtime.trackedGlobalsStart").SetVisibility(llvm.HiddenVisibility)
+	}
 
 	// Update trackedGlobalsLength, which contains the length (in words) of the
 	// globals bundle.
 	alignment := targetData.PrefTypeAlignment(llvm.PointerType(ctx.Int8Type(), 0))
 	trackedGlobalsLength := llvm.ConstInt(uintptrType, targetData.TypeAllocSize(globalsBundleType)/uint64(alignment), false)
 	mod.NamedGlobal("runtime.trackedGlobalsLength").SetInitializer(trackedGlobalsLength)
-	mod.NamedGlobal("runtime.trackedGlobalsLength").SetVisibility(llvm.HiddenVisibility)
+	if shouldHiveGlobals {
+		mod.NamedGlobal("runtime.trackedGlobalsLength").SetVisibility(llvm.HiddenVisibility)
+	}
 
 	// Create a bitmap (a new global) that stores for each word in the globals
 	// bundle whether it contains a pointer. This allows globals to be scanned
@@ -360,7 +369,9 @@ func AddGlobalsBitmap(mod llvm.Module) bool {
 	bitmapOld.ReplaceAllUsesWith(llvm.ConstBitCast(bitmapNew, bitmapOld.Type()))
 	bitmapNew.SetInitializer(bitmapArray)
 	bitmapNew.SetName("runtime.trackedGlobalsBitmap")
-	bitmapNew.SetVisibility(llvm.HiddenVisibility)
+	if shouldHiveGlobals {
+		bitmapNew.SetVisibility(llvm.HiddenVisibility)
+	}
 
 	return true // the IR was changed
 }
diff --git a/transform/gc_test.go b/transform/gc_test.go
index 64962f0a0b..d185aed338 100644
--- a/transform/gc_test.go
+++ b/transform/gc_test.go
@@ -9,13 +9,13 @@ import (
 func TestAddGlobalsBitmap(t *testing.T) {
 	t.Parallel()
 	testTransform(t, "testdata/gc-globals", func(mod llvm.Module) {
-		AddGlobalsBitmap(mod)
+		AddGlobalsBitmap(mod, false)
 	})
 }
 
 func TestMakeGCStackSlots(t *testing.T) {
 	t.Parallel()
 	testTransform(t, "testdata/gc-stackslots", func(mod llvm.Module) {
-		MakeGCStackSlots(mod)
+		MakeGCStackSlots(mod, false)
 	})
 }
diff --git a/transform/optimizer.go b/transform/optimizer.go
index 917083ce80..8cdfd94a5c 100644
--- a/transform/optimizer.go
+++ b/transform/optimizer.go
@@ -177,8 +177,9 @@ func Optimize(mod llvm.Module, config *compileopts.Config, optLevel, sizeLevel i
 	builder.Populate(modPasses)
 	modPasses.Run(mod)
 
-	hasGCPass := AddGlobalsBitmap(mod)
-	hasGCPass = MakeGCStackSlots(mod) || hasGCPass
+	shouldHideGlobals := shouldHideGlobalVariables(config.BuildTags())
+	hasGCPass := AddGlobalsBitmap(mod, shouldHideGlobals)
+	hasGCPass = MakeGCStackSlots(mod, shouldHideGlobals) || hasGCPass
 	if hasGCPass {
 		if err := llvm.VerifyModule(mod, llvm.PrintMessageAction); err != nil {
 			return []error{errors.New("GC pass caused a verification failure")}
@@ -228,3 +229,18 @@ func getFunctionsUsedInTransforms(config *compileopts.Config) []string {
 	}
 	return fnused
 }
+
+func shouldHideGlobalVariables(buildTags []string) bool {
+	for _, t := range buildTags {
+		// According to WASI spec, none of exports in WASI executable(Command) should no be accessed.
+		// Reference: https://github.com/WebAssembly/WASI/blob/master/design/application-abi.md#current-unstable-abi
+		//
+		// v0.19.0 of wasmetime, which is often refered to as the reference implementation of WASI,
+		// does not accept any exports except functions and the only limited variables like "table" or "memory".
+		// See: https://github.com/bytecodealliance/wasmtime/blob/60681d7019b38a5648b5615001ffa55442a64b83/crates/wasmtime/src/linker.rs#L401-L460
+		if t == "wasi" {
+			return true
+		}
+	}
+	return false
+}

From 7d985c5894f89ba8c6009483ac9bd1a3dfdb12ec Mon Sep 17 00:00:00 2001
From: mathetake <takeshi@tetrate.io>
Date: Sat, 19 Sep 2020 13:07:31 +0900
Subject: [PATCH 07/15] mv back syscall/wasi/* to runtime package

---
 src/runtime/runtime_wasm.go      | 20 ++++++---
 src/runtime/runtime_wasm_wasi.go | 74 ++++++++++++++++++++++++++++----
 src/syscall/wasi/clock.go        |  7 ---
 src/syscall/wasi/common.go       | 15 -------
 src/syscall/wasi/poll_oneoff.go  | 55 ------------------------
 5 files changed, 79 insertions(+), 92 deletions(-)
 delete mode 100644 src/syscall/wasi/clock.go
 delete mode 100644 src/syscall/wasi/common.go
 delete mode 100644 src/syscall/wasi/poll_oneoff.go

diff --git a/src/runtime/runtime_wasm.go b/src/runtime/runtime_wasm.go
index 8a9fad424c..e37d432e04 100644
--- a/src/runtime/runtime_wasm.go
+++ b/src/runtime/runtime_wasm.go
@@ -4,18 +4,26 @@ package runtime
 
 import (
 	"unsafe"
-
-	"github.com/tinygo-org/tinygo/src/syscall/wasi"
 )
 
+// Implements __wasi_iovec_t.
+type __wasi_iovec_t struct {
+	buf    unsafe.Pointer
+	bufLen uint
+}
+
+//go:wasm-module wasi_unstable
+//export fd_write
+func fd_write(id uint32, iovs *__wasi_iovec_t, iovs_len uint, nwritten *uint) (errno uint)
+
 func postinit() {}
 
 // Using global variables to avoid heap allocation.
 var (
 	putcharBuf   = byte(0)
-	putcharIOVec = wasi.IOVec{
-		Buf:    unsafe.Pointer(&putcharBuf),
-		BufLen: 1,
+	putcharIOVec = __wasi_iovec_t{
+		buf:    unsafe.Pointer(&putcharBuf),
+		bufLen: 1,
 	}
 )
 
@@ -24,7 +32,7 @@ func putchar(c byte) {
 	const stdout = 1
 	var nwritten uint
 	putcharBuf = c
-	wasi.Fd_write(stdout, &putcharIOVec, 1, &nwritten)
+	fd_write(stdout, &putcharIOVec, 1, &nwritten)
 }
 
 // Abort executes the wasm 'unreachable' instruction.
diff --git a/src/runtime/runtime_wasm_wasi.go b/src/runtime/runtime_wasm_wasi.go
index cfe8af1bb4..abc4063dcf 100644
--- a/src/runtime/runtime_wasm_wasi.go
+++ b/src/runtime/runtime_wasm_wasi.go
@@ -4,8 +4,6 @@ package runtime
 
 import (
 	"unsafe"
-
-	"github.com/tinygo-org/tinygo/src/syscall/wasi"
 )
 
 type timeUnit int64
@@ -32,11 +30,11 @@ const (
 )
 
 var (
-	sleepTicksSubscription = wasi.Subscription_t{
+	sleepTicksSubscription = __wasi_subscription_t{
 		UserData: 0,
-		U: wasi.Subscription_u_t{
-			Tag: wasi.Eventtype_t_clock,
-			U: wasi.Subscription_clock_t{
+		U: __wasi_subscription_u_t{
+			Tag: __wasi_eventtype_t_clock,
+			U: __wasi_subscription_clock_t{
 				UserData:  0,
 				ID:        0,
 				Timeout:   0,
@@ -45,17 +43,75 @@ var (
 			},
 		},
 	}
-	sleepTicksResult  = wasi.Event_t{}
+	sleepTicksResult  = __wasi_event_t{}
 	sleepTicksNEvents uint32
 )
 
 func sleepTicks(d timeUnit) {
 	sleepTicksSubscription.U.U.Timeout = int64(d)
-	wasi.Poll_oneoff(&sleepTicksSubscription, &sleepTicksResult, 1, &sleepTicksNEvents)
+	poll_oneoff(&sleepTicksSubscription, &sleepTicksResult, 1, &sleepTicksNEvents)
 }
 
 func ticks() timeUnit {
 	var nano int64
-	wasi.Clock_time_get(0, timePrecisionNanoseconds, &nano)
+	clock_time_get(0, timePrecisionNanoseconds, &nano)
 	return timeUnit(nano)
 }
+
+// Implementations of wasi_unstable APIs
+
+//go:wasm-module wasi_unstable
+//export clock_time_get
+func clock_time_get(clockid uint32, precision uint64, time *int64) (errno uint16)
+
+//go:wasm-module wasi_unstable
+//export poll_oneoff
+func poll_oneoff(in *__wasi_subscription_t, out *__wasi_event_t, nsubscriptions uint32, nevents *uint32) (errno uint16)
+
+type __wasi_eventtype_t = uint8
+
+const (
+	__wasi_eventtype_t_clock __wasi_eventtype_t = 0
+	// TODO: __wasi_eventtype_t_fd_read  __wasi_eventtype_t = 1
+	// TODO: __wasi_eventtype_t_fd_write __wasi_eventtype_t = 2
+)
+
+type (
+	// https://github.com/wasmerio/wasmer/blob/1.0.0-alpha3/lib/wasi/src/syscalls/types.rs#L584-L588
+	__wasi_subscription_t struct {
+		UserData uint64
+		U        __wasi_subscription_u_t
+	}
+
+	__wasi_subscription_u_t struct {
+		Tag __wasi_eventtype_t
+
+		// TODO: support fd_read/fd_write event
+		U __wasi_subscription_clock_t
+	}
+
+	// https://github.com/wasmerio/wasmer/blob/1.0.0-alpha3/lib/wasi/src/syscalls/types.rs#L711-L718
+	__wasi_subscription_clock_t struct {
+		UserData  uint64
+		ID        uint32
+		Timeout   int64
+		Precision int64
+		Flags     uint16
+	}
+)
+
+type (
+	// https://github.com/wasmerio/wasmer/blob/1.0.0-alpha3/lib/wasi/src/syscalls/types.rs#L191-L198
+	__wasi_event_t struct {
+		userData  uint64
+		errno     uint16
+		eventType __wasi_eventtype_t
+
+		// only used for fd_read or fd_write events
+		// TODO: support fd_read/fd_write event
+		_ struct {
+			nBytes uint64
+			flags  uint16
+		}
+	}
+)
diff --git a/src/syscall/wasi/clock.go b/src/syscall/wasi/clock.go
deleted file mode 100644
index ebb504f3b7..0000000000
--- a/src/syscall/wasi/clock.go
+++ /dev/null
@@ -1,7 +0,0 @@
-// +build wasm,wasi
-
-package wasi
-
-//go:wasm-module wasi_unstable
-//export clock_time_get
-func Clock_time_get(clockid uint32, precision uint64, time *int64) (errno uint16)
diff --git a/src/syscall/wasi/common.go b/src/syscall/wasi/common.go
deleted file mode 100644
index 1c94d7dfda..0000000000
--- a/src/syscall/wasi/common.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// +build wasm
-
-package wasi
-
-import "unsafe"
-
-// Implements __wasi_ciovec_t and __wasi_iovec_t.
-type IOVec struct {
-	Buf    unsafe.Pointer
-	BufLen uint
-}
-
-//go:wasm-module wasi_unstable
-//export fd_write
-func Fd_write(id uint32, iovs *IOVec, iovs_len uint, nwritten *uint) (errno uint)
diff --git a/src/syscall/wasi/poll_oneoff.go b/src/syscall/wasi/poll_oneoff.go
deleted file mode 100644
index c0544b8668..0000000000
--- a/src/syscall/wasi/poll_oneoff.go
+++ /dev/null
@@ -1,55 +0,0 @@
-// +build wasm,wasi
-
-package wasi
-
-//go:wasm-module wasi_unstable
-//export poll_oneoff
-func Poll_oneoff(in *Subscription_t, out *Event_t, nsubscriptions uint32, nevents *uint32) (errno uint16)
-
-type Eventtype_t = uint8
-
-const (
-	Eventtype_t_clock Eventtype_t = 0
-	// TODO: __wasi_eventtype_t_fd_read  __wasi_eventtype_t = 1
-	// TODO: __wasi_eventtype_t_fd_write __wasi_eventtype_t = 2
-)
-
-type (
-	// https://github.com/wasmerio/wasmer/blob/1.0.0-alpha3/lib/wasi/src/syscalls/types.rs#L584-L588
-	Subscription_t struct {
-		UserData uint64
-		U        Subscription_u_t
-	}
-
-	Subscription_u_t struct {
-		Tag Eventtype_t
-
-		// TODO: support fd_read/fd_write event
-		U Subscription_clock_t
-	}
-
-	// https://github.com/wasmerio/wasmer/blob/1.0.0-alpha3/lib/wasi/src/syscalls/types.rs#L711-L718
-	Subscription_clock_t struct {
-		UserData  uint64
-		ID        uint32
-		Timeout   int64
-		Precision int64
-		Flags     uint16
-	}
-)
-
-type (
-	// https://github.com/wasmerio/wasmer/blob/1.0.0-alpha3/lib/wasi/src/syscalls/types.rs#L191-L198
-	Event_t struct {
-		UserData  uint64
-		Errno     uint16
-		EventType Eventtype_t
-
-		// only used for fd_read or fd_write events
-		// TODO: support fd_read/fd_write event
-		_ struct {
-			NBytes uint64
-			Flags  uint16
-		}
-	}
-)

From cb4d61f4f1d7e1d5f6c990cbe5bcb558313136e4 Mon Sep 17 00:00:00 2001
From: mathetake <takeshi@tetrate.io>
Date: Sat, 19 Sep 2020 13:53:27 +0900
Subject: [PATCH 08/15] WASI: add test

---
 .circleci/config.yml |  6 ++++++
 main_test.go         | 10 +++++++++-
 targets/wasi.json    |  2 +-
 transform/gc.go      | 14 ++++++++------
 4 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index eedf08d27d..29e3de8aa4 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -44,6 +44,11 @@ commands:
           command: |
             wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb
             sudo apt install ./google-chrome-stable_current_amd64.deb
+  install-wasmtime:
+    steps:
+      - run:
+          name: "Install wasmtime"
+          command: curl https://wasmtime.dev/install.sh -sSf | bash
   install-xtensa-toolchain:
     parameters:
       variant:
@@ -91,6 +96,7 @@ commands:
           llvm: "<<parameters.llvm>>"
       - install-node
       - install-chrome
+      - install-wasmtime
       - restore_cache:
           keys:
             - go-cache-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}
diff --git a/main_test.go b/main_test.go
index f66117b90a..3434cc27d3 100644
--- a/main_test.go
+++ b/main_test.go
@@ -97,6 +97,10 @@ func TestCompiler(t *testing.T) {
 			t.Run("WebAssembly", func(t *testing.T) {
 				runPlatTests("wasm", matches, t)
 			})
+
+			t.Run("WASI", func(t *testing.T) {
+				runPlatTests("wasi", matches, t)
+			})
 		}
 	}
 }
@@ -109,7 +113,6 @@ func runPlatTests(target string, matches []string, t *testing.T) {
 
 		t.Run(filepath.Base(path), func(t *testing.T) {
 			t.Parallel()
-
 			runTest(path, target, t)
 		})
 	}
@@ -161,6 +164,11 @@ func runTest(path, target string, t *testing.T) {
 		PrintSizes: "",
 		WasmAbi:    "js",
 	}
+
+	if target == "wasi" {
+		config.WasmAbi = "generic"
+	}
+
 	binary := filepath.Join(tmpdir, "test")
 	err = runBuild("./"+path, binary, config)
 	if err != nil {
diff --git a/targets/wasi.json b/targets/wasi.json
index 09ab606d72..edbed161fa 100644
--- a/targets/wasi.json
+++ b/targets/wasi.json
@@ -18,5 +18,5 @@
 		"--no-demangle",
 		"{root}/lib/wasi-libc/sysroot/lib/wasm32-wasi/libc.a"
 	],
-	"emulator":      ["node", "targets/wasm_exec.js"]
+	"emulator":      ["wasmtime"]
 }
diff --git a/transform/gc.go b/transform/gc.go
index 74109021c2..38edc106f2 100644
--- a/transform/gc.go
+++ b/transform/gc.go
@@ -11,9 +11,6 @@ import (
 func MakeGCStackSlots(mod llvm.Module, shouldHiveGlobals bool) bool {
 	// Check whether there are allocations at all.
 	alloc := mod.NamedFunction("runtime.alloc")
-	if shouldHiveGlobals {
-		alloc.SetVisibility(llvm.HiddenVisibility)
-	}
 	if alloc.IsNil() {
 		// Nothing to. Make sure all remaining bits and pieces for stack
 		// chains are neutralized.
@@ -22,12 +19,17 @@ func MakeGCStackSlots(mod llvm.Module, shouldHiveGlobals bool) bool {
 		}
 		stackChainStart := mod.NamedGlobal("runtime.stackChainStart")
 		if !stackChainStart.IsNil() {
+			stackChainStart.SetVisibility(llvm.HiddenVisibility)
 			stackChainStart.SetInitializer(llvm.ConstNull(stackChainStart.Type().ElementType()))
 			stackChainStart.SetGlobalConstant(true)
 		}
 		return false
 	}
 
+	if shouldHiveGlobals {
+		alloc.SetVisibility(llvm.HiddenVisibility)
+	}
+
 	trackPointer := mod.NamedFunction("runtime.trackPointer")
 	if trackPointer.IsNil() || trackPointer.FirstUse().IsNil() {
 		return false // nothing to do
@@ -88,9 +90,6 @@ func MakeGCStackSlots(mod llvm.Module, shouldHiveGlobals bool) bool {
 
 	// Collect some variables used below in the loop.
 	stackChainStart := mod.NamedGlobal("runtime.stackChainStart")
-	if shouldHiveGlobals {
-		stackChainStart.SetVisibility(llvm.HiddenVisibility)
-	}
 	if stackChainStart.IsNil() {
 		// This may be reached in a weird scenario where we call runtime.alloc but the garbage collector is unreachable.
 		// This can be accomplished by allocating 0 bytes.
@@ -100,6 +99,9 @@ func MakeGCStackSlots(mod llvm.Module, shouldHiveGlobals bool) bool {
 		}
 		return false
 	}
+	if shouldHiveGlobals {
+		stackChainStart.SetVisibility(llvm.HiddenVisibility)
+	}
 	stackChainStartType := stackChainStart.Type().ElementType()
 	stackChainStart.SetInitializer(llvm.ConstNull(stackChainStartType))
 

From f40eebb653f8de837d0856410e9e0f3b6959efc9 Mon Sep 17 00:00:00 2001
From: mathetake <takeshi@tetrate.io>
Date: Sat, 19 Sep 2020 14:01:27 +0900
Subject: [PATCH 09/15] unexport wasi types

---
 src/runtime/runtime_wasm_wasi.go | 38 ++++++++++++++++----------------
 1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/src/runtime/runtime_wasm_wasi.go b/src/runtime/runtime_wasm_wasi.go
index abc4063dcf..99a34ebb4f 100644
--- a/src/runtime/runtime_wasm_wasi.go
+++ b/src/runtime/runtime_wasm_wasi.go
@@ -31,15 +31,15 @@ const (
 
 var (
 	sleepTicksSubscription = __wasi_subscription_t{
-		UserData: 0,
-		U: __wasi_subscription_u_t{
-			Tag: __wasi_eventtype_t_clock,
-			U: __wasi_subscription_clock_t{
-				UserData:  0,
-				ID:        0,
-				Timeout:   0,
-				Precision: timePrecisionNanoseconds,
-				Flags:     0,
+		userData: 0,
+		u: __wasi_subscription_u_t{
+			tag: __wasi_eventtype_t_clock,
+			u: __wasi_subscription_clock_t{
+				userData:  0,
+				id:        0,
+				timeout:   0,
+				precision: timePrecisionNanoseconds,
+				flags:     0,
 			},
 		},
 	}
@@ -48,7 +48,7 @@ var (
 )
 
 func sleepTicks(d timeUnit) {
-	sleepTicksSubscription.U.U.Timeout = int64(d)
+	sleepTicksSubscription.u.u.timeout = int64(d)
 	poll_oneoff(&sleepTicksSubscription, &sleepTicksResult, 1, &sleepTicksNEvents)
 }
 
@@ -79,24 +79,24 @@ const (
 type (
 	// https://github.com/wasmerio/wasmer/blob/1.0.0-alpha3/lib/wasi/src/syscalls/types.rs#L584-L588
 	__wasi_subscription_t struct {
-		UserData uint64
-		U        __wasi_subscription_u_t
+		userData uint64
+		u        __wasi_subscription_u_t
 	}
 
 	__wasi_subscription_u_t struct {
-		Tag __wasi_eventtype_t
+		tag __wasi_eventtype_t
 
 		// TODO: support fd_read/fd_write event
-		U __wasi_subscription_clock_t
+		u __wasi_subscription_clock_t
 	}
 
 	// https://github.com/wasmerio/wasmer/blob/1.0.0-alpha3/lib/wasi/src/syscalls/types.rs#L711-L718
 	__wasi_subscription_clock_t struct {
-		UserData  uint64
-		ID        uint32
-		Timeout   int64
-		Precision int64
-		Flags     uint16
+		userData  uint64
+		id        uint32
+		timeout   int64
+		precision int64
+		flags     uint16
 	}
 )
 

From 507010eed45a3ff193dd9e66af6ea2ba0ca048a7 Mon Sep 17 00:00:00 2001
From: mathetake <takeshi@tetrate.io>
Date: Sat, 19 Sep 2020 15:05:45 +0900
Subject: [PATCH 10/15] WASI test: fix wasmtime path

---
 .circleci/config.yml | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index 29e3de8aa4..5c999d8632 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -48,7 +48,9 @@ commands:
     steps:
       - run:
           name: "Install wasmtime"
-          command: curl https://wasmtime.dev/install.sh -sSf | bash
+          command: |
+            curl https://wasmtime.dev/install.sh -sSf | bash
+            sudo ln -s ~/.wasmtime/bin/wasmtime /usr/local/bin/wasmtime
   install-xtensa-toolchain:
     parameters:
       variant:
@@ -99,7 +101,7 @@ commands:
       - install-wasmtime
       - restore_cache:
           keys:
-            - go-cache-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}
+            - go-cache-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}-
             - go-cache-v2-{{ checksum "go.mod" }}
       - llvm-source-linux
       - run: go install -tags=llvm<<parameters.llvm>> .
@@ -140,11 +142,12 @@ commands:
                 gcc-avr \
                 avr-libc
       - install-node
+      - install-wasmtime
       - install-xtensa-toolchain:
           variant: "linux-amd64"
       - restore_cache:
           keys:
-            - go-cache-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}
+            - go-cache-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}-
             - go-cache-v2-{{ checksum "go.mod" }}
       - llvm-source-linux
       - restore_cache:
@@ -200,11 +203,12 @@ commands:
                 gcc-avr \
                 avr-libc
       - install-node
+      - install-wasmtime
       - install-xtensa-toolchain:
           variant: "linux-amd64"
       - restore_cache:
           keys:
-            - go-cache-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}
+            - go-cache-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}-
             - go-cache-v2-{{ checksum "go.mod" }}
       - llvm-source-linux
       - restore_cache:
@@ -277,7 +281,7 @@ commands:
           variant: "macos"
       - restore_cache:
           keys:
-            - go-cache-macos-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}
+            - go-cache-macos-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}-
             - go-cache-macos-v2-{{ checksum "go.mod" }}
       - restore_cache:
           keys:

From 6e68e97469691bd2d8c1227d144b7cab01a7fc74 Mon Sep 17 00:00:00 2001
From: mathetake <takeshi@tetrate.io>
Date: Sat, 19 Sep 2020 17:44:42 +0900
Subject: [PATCH 11/15] stop changing visibility of runtime.alloc

---
 .circleci/config.yml   | 8 ++++----
 transform/gc.go        | 8 +++-----
 transform/optimizer.go | 4 ++--
 3 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index 5c999d8632..15ca09e010 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -101,7 +101,7 @@ commands:
       - install-wasmtime
       - restore_cache:
           keys:
-            - go-cache-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}-
+            - go-cache-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}
             - go-cache-v2-{{ checksum "go.mod" }}
       - llvm-source-linux
       - run: go install -tags=llvm<<parameters.llvm>> .
@@ -147,7 +147,7 @@ commands:
           variant: "linux-amd64"
       - restore_cache:
           keys:
-            - go-cache-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}-
+            - go-cache-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}
             - go-cache-v2-{{ checksum "go.mod" }}
       - llvm-source-linux
       - restore_cache:
@@ -208,7 +208,7 @@ commands:
           variant: "linux-amd64"
       - restore_cache:
           keys:
-            - go-cache-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}-
+            - go-cache-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}
             - go-cache-v2-{{ checksum "go.mod" }}
       - llvm-source-linux
       - restore_cache:
@@ -281,7 +281,7 @@ commands:
           variant: "macos"
       - restore_cache:
           keys:
-            - go-cache-macos-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}-
+            - go-cache-macos-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}
             - go-cache-macos-v2-{{ checksum "go.mod" }}
       - restore_cache:
           keys:
diff --git a/transform/gc.go b/transform/gc.go
index 38edc106f2..86060d3b1d 100644
--- a/transform/gc.go
+++ b/transform/gc.go
@@ -19,17 +19,15 @@ func MakeGCStackSlots(mod llvm.Module, shouldHiveGlobals bool) bool {
 		}
 		stackChainStart := mod.NamedGlobal("runtime.stackChainStart")
 		if !stackChainStart.IsNil() {
-			stackChainStart.SetVisibility(llvm.HiddenVisibility)
+			if shouldHiveGlobals {
+				stackChainStart.SetVisibility(llvm.HiddenVisibility)
+			}
 			stackChainStart.SetInitializer(llvm.ConstNull(stackChainStart.Type().ElementType()))
 			stackChainStart.SetGlobalConstant(true)
 		}
 		return false
 	}
 
-	if shouldHiveGlobals {
-		alloc.SetVisibility(llvm.HiddenVisibility)
-	}
-
 	trackPointer := mod.NamedFunction("runtime.trackPointer")
 	if trackPointer.IsNil() || trackPointer.FirstUse().IsNil() {
 		return false // nothing to do
diff --git a/transform/optimizer.go b/transform/optimizer.go
index 8cdfd94a5c..c7058208f7 100644
--- a/transform/optimizer.go
+++ b/transform/optimizer.go
@@ -232,10 +232,10 @@ func getFunctionsUsedInTransforms(config *compileopts.Config) []string {
 
 func shouldHideGlobalVariables(buildTags []string) bool {
 	for _, t := range buildTags {
-		// According to WASI spec, none of exports in WASI executable(Command) should no be accessed.
+		// According to WASI spec, global variables in WASI executable(Command) should not be exported.
 		// Reference: https://github.com/WebAssembly/WASI/blob/master/design/application-abi.md#current-unstable-abi
 		//
-		// v0.19.0 of wasmetime, which is often refered to as the reference implementation of WASI,
+		// v0.19.0 of wasmtime, which is often referred to as the reference implementation of WASI,
 		// does not accept any exports except functions and the only limited variables like "table" or "memory".
 		// See: https://github.com/bytecodealliance/wasmtime/blob/60681d7019b38a5648b5615001ffa55442a64b83/crates/wasmtime/src/linker.rs#L401-L460
 		if t == "wasi" {

From 6ef9dc02f5cd3a7af28897d23a2711eba9890e29 Mon Sep 17 00:00:00 2001
From: mathetake <takeshi@tetrate.io>
Date: Wed, 23 Sep 2020 09:11:11 +0900
Subject: [PATCH 12/15] use GOOS=linux, GOARCH=arm for wasi target

Signed-off-by: mathetake <takeshi@tetrate.io>
---
 loader/goroot.go          | 39 ++-------------------------------------
 loader/loader.go          |  5 +----
 main_test.go              |  8 ++++----
 src/time/zoneinfo_wasi.go | 13 -------------
 targets/wasi.json         |  6 +++---
 5 files changed, 10 insertions(+), 61 deletions(-)
 delete mode 100644 src/time/zoneinfo_wasi.go

diff --git a/loader/goroot.go b/loader/goroot.go
index 4b43fe7b84..5fa4bea071 100644
--- a/loader/goroot.go
+++ b/loader/goroot.go
@@ -15,7 +15,6 @@ import (
 	"path"
 	"path/filepath"
 	"runtime"
-	"strings"
 	"sync"
 
 	"github.com/tinygo-org/tinygo/compileopts"
@@ -89,10 +88,7 @@ func GetCachedGoroot(config *compileopts.Config) (string, error) {
 			return "", err
 		}
 	}
-	err = mergeDirectory(goroot, tinygoroot, tmpgoroot, "", pathsToOverride(
-		needsSyscallPackage(config.BuildTags()),
-		needsTimePackage(config.BuildTags()),
-	))
+	err = mergeDirectory(goroot, tinygoroot, tmpgoroot, "", pathsToOverride(needsSyscallPackage(config.BuildTags())))
 	if err != nil {
 		return "", err
 	}
@@ -168,17 +164,6 @@ func mergeDirectory(goroot, tinygoroot, tmpgoroot, importPath string, overrides
 			return err
 		}
 		for _, e := range gorootEntries {
-			if isMergeTargetEntry(importPath, e.Name()) {
-				// In this case, we have files both from TinyGo and Go.
-				// As of now, this is only for WASI to have *_wasi.go files as replacements for *_js.go files
-				newname := filepath.Join(tmpgoroot, "src", importPath, e.Name())
-				oldname := filepath.Join(goroot, "src", importPath, e.Name())
-				err := symlink(oldname, newname)
-				if err != nil {
-					return err
-				}
-				continue
-			}
 			if !e.IsDir() {
 				// Don't merge in files from Go. Otherwise we'd end up with a
 				// weird syscall package with files from both roots.
@@ -200,11 +185,6 @@ func mergeDirectory(goroot, tinygoroot, tmpgoroot, importPath string, overrides
 	return nil
 }
 
-func isMergeTargetEntry(importPath string, name string) bool {
-	// TODO: add crypto/rand
-	return importPath == "time" && !strings.HasSuffix(name, "_js.go")
-}
-
 // needsSyscallPackage returns whether the syscall package should be overriden
 // with the TinyGo version. This is the case on some targets.
 func needsSyscallPackage(buildTags []string) bool {
@@ -216,20 +196,9 @@ func needsSyscallPackage(buildTags []string) bool {
 	return false
 }
 
-// needsTimePackage returns whether the time package should be merged
-// with the TinyGo version. This is the case on some targets.
-func needsTimePackage(buildTags []string) bool {
-	for _, tag := range buildTags {
-		if tag == "wasi" {
-			return true
-		}
-	}
-	return false
-}
-
 // The boolean indicates whether to merge the subdirs. True means merge, false
 // means use the TinyGo version.
-func pathsToOverride(needsSyscallPackage, needsTimePackage bool) map[string]bool {
+func pathsToOverride(needsSyscallPackage bool) map[string]bool {
 	paths := map[string]bool{
 		"/":                     true,
 		"device/":               false,
@@ -248,10 +217,6 @@ func pathsToOverride(needsSyscallPackage, needsTimePackage bool) map[string]bool
 	if needsSyscallPackage {
 		paths["syscall/"] = true // include syscall/js
 	}
-
-	if needsTimePackage {
-		paths["time/"] = true
-	}
 	return paths
 }
 
diff --git a/loader/loader.go b/loader/loader.go
index 159fa8a195..6200cc574b 100644
--- a/loader/loader.go
+++ b/loader/loader.go
@@ -223,10 +223,7 @@ func (p *Program) getOriginalPath(path string) string {
 			originalPath = realgorootPath
 		}
 		maybeInTinyGoRoot := false
-		for prefix := range pathsToOverride(
-			needsSyscallPackage(p.config.BuildTags()),
-			needsTimePackage(p.config.BuildTags()),
-		) {
+		for prefix := range pathsToOverride(needsSyscallPackage(p.config.BuildTags())) {
 			if !strings.HasPrefix(relpath, prefix) {
 				continue
 			}
diff --git a/main_test.go b/main_test.go
index 3434cc27d3..e12b165ec0 100644
--- a/main_test.go
+++ b/main_test.go
@@ -97,12 +97,12 @@ func TestCompiler(t *testing.T) {
 			t.Run("WebAssembly", func(t *testing.T) {
 				runPlatTests("wasm", matches, t)
 			})
-
-			t.Run("WASI", func(t *testing.T) {
-				runPlatTests("wasi", matches, t)
-			})
 		}
 	}
+
+	t.Run("WASI", func(t *testing.T) {
+		runPlatTests("wasi", matches, t)
+	})
 }
 
 func runPlatTests(target string, matches []string, t *testing.T) {
diff --git a/src/time/zoneinfo_wasi.go b/src/time/zoneinfo_wasi.go
deleted file mode 100644
index ce3f8786b2..0000000000
--- a/src/time/zoneinfo_wasi.go
+++ /dev/null
@@ -1,13 +0,0 @@
-// +build wasi
-
-// should be replaced with original time/zoneinfo_js.go
-
-package time
-
-// TODO: https://github.com/WebAssembly/WASI/issues/25
-
-var zoneSources []string // TODO:
-
-func initLocal() {
-	// TODO:
-}
diff --git a/targets/wasi.json b/targets/wasi.json
index edbed161fa..97f7848f9b 100644
--- a/targets/wasi.json
+++ b/targets/wasi.json
@@ -1,8 +1,8 @@
 {
 	"llvm-target":   "wasm32--wasi",
-	"build-tags":    ["js", "wasm", "wasi"],
-	"goos":          "js",
-	"goarch":        "wasm",
+	"build-tags":    ["wasm", "wasi"],
+	"goos":          "linux",
+	"goarch":        "arm",
 	"compiler":      "clang",
 	"linker":        "wasm-ld",
 	"cflags": [

From d852bba278bd3993a6faf2da6203c938062be78b Mon Sep 17 00:00:00 2001
From: mathetake <takeshi@tetrate.io>
Date: Wed, 23 Sep 2020 09:23:58 +0900
Subject: [PATCH 13/15] WASI: fix build tags for os/runtime packages

Signed-off-by: mathetake <takeshi@tetrate.io>
---
 src/os/file_unix.go                | 2 +-
 src/runtime/arch_arm.go            | 2 +-
 src/runtime/runtime_unix.go        | 2 +-
 src/runtime/runtime_unix_heap.go   | 2 +-
 src/runtime/runtime_unix_noheap.go | 2 +-
 5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/os/file_unix.go b/src/os/file_unix.go
index e77d6773fb..84d738b0ca 100644
--- a/src/os/file_unix.go
+++ b/src/os/file_unix.go
@@ -1,4 +1,4 @@
-// +build darwin linux,!baremetal freebsd,!baremetal
+// +build darwin linux,!baremetal,!wasi freebsd,!baremetal
 
 package os
 
diff --git a/src/runtime/arch_arm.go b/src/runtime/arch_arm.go
index 0a98f6d532..e2dc4b5bfe 100644
--- a/src/runtime/arch_arm.go
+++ b/src/runtime/arch_arm.go
@@ -1,4 +1,4 @@
-// +build arm,!baremetal arm,arm7tdmi
+// +build arm,!baremetal,!wasm arm,arm7tdmi
 
 package runtime
 
diff --git a/src/runtime/runtime_unix.go b/src/runtime/runtime_unix.go
index a3c2b4471b..ef4b825856 100644
--- a/src/runtime/runtime_unix.go
+++ b/src/runtime/runtime_unix.go
@@ -1,4 +1,4 @@
-// +build darwin linux,!baremetal freebsd,!baremetal
+// +build darwin linux,!baremetal,!wasi freebsd,!baremetal
 // +build !nintendoswitch
 
 package runtime
diff --git a/src/runtime/runtime_unix_heap.go b/src/runtime/runtime_unix_heap.go
index 14168f4387..1aefd2f615 100644
--- a/src/runtime/runtime_unix_heap.go
+++ b/src/runtime/runtime_unix_heap.go
@@ -1,4 +1,4 @@
-// +build darwin linux,!baremetal freebsd,!baremetal
+// +build darwin linux,!baremetal,!wasi freebsd,!baremetal
 // +build !nintendoswitch
 
 // +build gc.conservative gc.leaking
diff --git a/src/runtime/runtime_unix_noheap.go b/src/runtime/runtime_unix_noheap.go
index bf7f675987..f9826ac5d7 100644
--- a/src/runtime/runtime_unix_noheap.go
+++ b/src/runtime/runtime_unix_noheap.go
@@ -1,4 +1,4 @@
-// +build darwin linux,!baremetal freebsd,!baremetal
+// +build darwin linux,!baremetal,!wasi freebsd,!baremetal
 
 // +build !nintendoswitch
 

From 5140e530bcea8edd1fa80750690909cf3a1f2fe1 Mon Sep 17 00:00:00 2001
From: mathetake <takeshi@tetrate.io>
Date: Wed, 23 Sep 2020 09:34:33 +0900
Subject: [PATCH 14/15] run WASI test only on Linux

Signed-off-by: mathetake <takeshi@tetrate.io>
---
 main_test.go | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/main_test.go b/main_test.go
index e12b165ec0..ac01baafaa 100644
--- a/main_test.go
+++ b/main_test.go
@@ -98,11 +98,11 @@ func TestCompiler(t *testing.T) {
 				runPlatTests("wasm", matches, t)
 			})
 		}
-	}
 
-	t.Run("WASI", func(t *testing.T) {
-		runPlatTests("wasi", matches, t)
-	})
+		t.Run("WASI", func(t *testing.T) {
+			runPlatTests("wasi", matches, t)
+		})
+	}
 }
 
 func runPlatTests(target string, matches []string, t *testing.T) {

From 62a9104ec6eec18e3014e76eedcc6d3387aa5494 Mon Sep 17 00:00:00 2001
From: mathetake <takeshi@tetrate.io>
Date: Wed, 23 Sep 2020 10:02:52 +0900
Subject: [PATCH 15/15] set InternalLinkage instead of changing visibility

Signed-off-by: mathetake <takeshi@tetrate.io>
---
 loader/loader.go                        |  2 +-
 transform/gc.go                         | 24 +++++++-----------------
 transform/gc_test.go                    |  4 ++--
 transform/optimizer.go                  | 20 ++------------------
 transform/testdata/gc-globals.out.ll    |  6 +++---
 transform/testdata/gc-stackslots.out.ll |  2 +-
 6 files changed, 16 insertions(+), 42 deletions(-)

diff --git a/loader/loader.go b/loader/loader.go
index 6200cc574b..847acc2584 100644
--- a/loader/loader.go
+++ b/loader/loader.go
@@ -166,6 +166,7 @@ func Load(config *compileopts.Config, inputPkgs []string, clangHeaders string, t
 					Err:         err,
 				}
 			}
+			return nil, err
 		}
 		if config.TestConfig.CompileTestBinary {
 			// When creating a test binary, `go list` will list two or three
@@ -229,7 +230,6 @@ func (p *Program) getOriginalPath(path string) string {
 			}
 			maybeInTinyGoRoot = true
 		}
-
 		if maybeInTinyGoRoot {
 			tinygoPath := filepath.Join(goenv.Get("TINYGOROOT"), "src", relpath)
 			if _, err := os.Stat(tinygoPath); err == nil {
diff --git a/transform/gc.go b/transform/gc.go
index 86060d3b1d..0688604986 100644
--- a/transform/gc.go
+++ b/transform/gc.go
@@ -8,7 +8,7 @@ import (
 
 // MakeGCStackSlots converts all calls to runtime.trackPointer to explicit
 // stores to stack slots that are scannable by the GC.
-func MakeGCStackSlots(mod llvm.Module, shouldHiveGlobals bool) bool {
+func MakeGCStackSlots(mod llvm.Module) bool {
 	// Check whether there are allocations at all.
 	alloc := mod.NamedFunction("runtime.alloc")
 	if alloc.IsNil() {
@@ -19,9 +19,7 @@ func MakeGCStackSlots(mod llvm.Module, shouldHiveGlobals bool) bool {
 		}
 		stackChainStart := mod.NamedGlobal("runtime.stackChainStart")
 		if !stackChainStart.IsNil() {
-			if shouldHiveGlobals {
-				stackChainStart.SetVisibility(llvm.HiddenVisibility)
-			}
+			stackChainStart.SetLinkage(llvm.InternalLinkage)
 			stackChainStart.SetInitializer(llvm.ConstNull(stackChainStart.Type().ElementType()))
 			stackChainStart.SetGlobalConstant(true)
 		}
@@ -97,9 +95,7 @@ func MakeGCStackSlots(mod llvm.Module, shouldHiveGlobals bool) bool {
 		}
 		return false
 	}
-	if shouldHiveGlobals {
-		stackChainStart.SetVisibility(llvm.HiddenVisibility)
-	}
+	stackChainStart.SetLinkage(llvm.InternalLinkage)
 	stackChainStartType := stackChainStart.Type().ElementType()
 	stackChainStart.SetInitializer(llvm.ConstNull(stackChainStartType))
 
@@ -291,7 +287,7 @@ func MakeGCStackSlots(mod llvm.Module, shouldHiveGlobals bool) bool {
 // bitmap (bit vector) to locate all the pointers in this large global. This
 // bitmap allows the GC to know in advance where exactly all the pointers live
 // in the large globals bundle, to avoid false positives.
-func AddGlobalsBitmap(mod llvm.Module, shouldHiveGlobals bool) bool {
+func AddGlobalsBitmap(mod llvm.Module) bool {
 	if mod.NamedGlobal("runtime.trackedGlobalsStart").IsNil() {
 		return false // nothing to do: no GC in use
 	}
@@ -339,18 +335,14 @@ func AddGlobalsBitmap(mod llvm.Module, shouldHiveGlobals bool) bool {
 	// Update trackedGlobalsStart, which points to the globals bundle.
 	trackedGlobalsStart := llvm.ConstPtrToInt(globalsBundle, uintptrType)
 	mod.NamedGlobal("runtime.trackedGlobalsStart").SetInitializer(trackedGlobalsStart)
-	if shouldHiveGlobals {
-		mod.NamedGlobal("runtime.trackedGlobalsStart").SetVisibility(llvm.HiddenVisibility)
-	}
+	mod.NamedGlobal("runtime.trackedGlobalsStart").SetLinkage(llvm.InternalLinkage)
 
 	// Update trackedGlobalsLength, which contains the length (in words) of the
 	// globals bundle.
 	alignment := targetData.PrefTypeAlignment(llvm.PointerType(ctx.Int8Type(), 0))
 	trackedGlobalsLength := llvm.ConstInt(uintptrType, targetData.TypeAllocSize(globalsBundleType)/uint64(alignment), false)
+	mod.NamedGlobal("runtime.trackedGlobalsLength").SetLinkage(llvm.InternalLinkage)
 	mod.NamedGlobal("runtime.trackedGlobalsLength").SetInitializer(trackedGlobalsLength)
-	if shouldHiveGlobals {
-		mod.NamedGlobal("runtime.trackedGlobalsLength").SetVisibility(llvm.HiddenVisibility)
-	}
 
 	// Create a bitmap (a new global) that stores for each word in the globals
 	// bundle whether it contains a pointer. This allows globals to be scanned
@@ -369,9 +361,7 @@ func AddGlobalsBitmap(mod llvm.Module, shouldHiveGlobals bool) bool {
 	bitmapOld.ReplaceAllUsesWith(llvm.ConstBitCast(bitmapNew, bitmapOld.Type()))
 	bitmapNew.SetInitializer(bitmapArray)
 	bitmapNew.SetName("runtime.trackedGlobalsBitmap")
-	if shouldHiveGlobals {
-		bitmapNew.SetVisibility(llvm.HiddenVisibility)
-	}
+	bitmapNew.SetLinkage(llvm.InternalLinkage)
 
 	return true // the IR was changed
 }
diff --git a/transform/gc_test.go b/transform/gc_test.go
index d185aed338..64962f0a0b 100644
--- a/transform/gc_test.go
+++ b/transform/gc_test.go
@@ -9,13 +9,13 @@ import (
 func TestAddGlobalsBitmap(t *testing.T) {
 	t.Parallel()
 	testTransform(t, "testdata/gc-globals", func(mod llvm.Module) {
-		AddGlobalsBitmap(mod, false)
+		AddGlobalsBitmap(mod)
 	})
 }
 
 func TestMakeGCStackSlots(t *testing.T) {
 	t.Parallel()
 	testTransform(t, "testdata/gc-stackslots", func(mod llvm.Module) {
-		MakeGCStackSlots(mod, false)
+		MakeGCStackSlots(mod)
 	})
 }
diff --git a/transform/optimizer.go b/transform/optimizer.go
index c7058208f7..917083ce80 100644
--- a/transform/optimizer.go
+++ b/transform/optimizer.go
@@ -177,9 +177,8 @@ func Optimize(mod llvm.Module, config *compileopts.Config, optLevel, sizeLevel i
 	builder.Populate(modPasses)
 	modPasses.Run(mod)
 
-	shouldHideGlobals := shouldHideGlobalVariables(config.BuildTags())
-	hasGCPass := AddGlobalsBitmap(mod, shouldHideGlobals)
-	hasGCPass = MakeGCStackSlots(mod, shouldHideGlobals) || hasGCPass
+	hasGCPass := AddGlobalsBitmap(mod)
+	hasGCPass = MakeGCStackSlots(mod) || hasGCPass
 	if hasGCPass {
 		if err := llvm.VerifyModule(mod, llvm.PrintMessageAction); err != nil {
 			return []error{errors.New("GC pass caused a verification failure")}
@@ -229,18 +228,3 @@ func getFunctionsUsedInTransforms(config *compileopts.Config) []string {
 	}
 	return fnused
 }
-
-func shouldHideGlobalVariables(buildTags []string) bool {
-	for _, t := range buildTags {
-		// According to WASI spec, global variables in WASI executable(Command) should not be exported.
-		// Reference: https://github.com/WebAssembly/WASI/blob/master/design/application-abi.md#current-unstable-abi
-		//
-		// v0.19.0 of wasmtime, which is often referred to as the reference implementation of WASI,
-		// does not accept any exports except functions and the only limited variables like "table" or "memory".
-		// See: https://github.com/bytecodealliance/wasmtime/blob/60681d7019b38a5648b5615001ffa55442a64b83/crates/wasmtime/src/linker.rs#L401-L460
-		if t == "wasi" {
-			return true
-		}
-	}
-	return false
-}
diff --git a/transform/testdata/gc-globals.out.ll b/transform/testdata/gc-globals.out.ll
index 45b80b7d84..905e8eafa1 100644
--- a/transform/testdata/gc-globals.out.ll
+++ b/transform/testdata/gc-globals.out.ll
@@ -7,11 +7,11 @@ target triple = "wasm32-unknown-unknown-wasm"
 @globalInt = global i32 5
 @constString = constant %runtime._string zeroinitializer
 @constInterface = constant %runtime._interface zeroinitializer
-@runtime.trackedGlobalsLength = global i32 4
+@runtime.trackedGlobalsLength = internal global i32 4
 @runtime.trackedGlobalsBitmap = external global [0 x i8]
-@runtime.trackedGlobalsStart = global i32 ptrtoint ({ %runtime._string, %runtime._interface }* @tinygo.trackedGlobals to i32)
+@runtime.trackedGlobalsStart = internal global i32 ptrtoint ({ %runtime._string, %runtime._interface }* @tinygo.trackedGlobals to i32)
 @tinygo.trackedGlobals = internal unnamed_addr global { %runtime._string, %runtime._interface } zeroinitializer
-@runtime.trackedGlobalsBitmap.1 = global [1 x i8] c"\09"
+@runtime.trackedGlobalsBitmap.1 = internal global [1 x i8] c"\09"
 
 define void @main() {
   %1 = load i32, i32* @globalInt
diff --git a/transform/testdata/gc-stackslots.out.ll b/transform/testdata/gc-stackslots.out.ll
index efcc3ed25e..9acb0abe7d 100644
--- a/transform/testdata/gc-stackslots.out.ll
+++ b/transform/testdata/gc-stackslots.out.ll
@@ -3,7 +3,7 @@ target triple = "wasm32-unknown-unknown-wasm"
 
 %runtime.stackChainObject = type { %runtime.stackChainObject*, i32 }
 
-@runtime.stackChainStart = global %runtime.stackChainObject* null
+@runtime.stackChainStart = internal global %runtime.stackChainObject* null
 @someGlobal = global i8 3
 
 declare void @runtime.trackPointer(i8* nocapture readonly)