From 62e1c3ebb7ae87fbc4ed53cb2f0572d72b284e77 Mon Sep 17 00:00:00 2001
From: Ayke van Laethem <aykevanlaethem@gmail.com>
Date: Thu, 15 Sep 2022 16:53:40 +0200
Subject: [PATCH] wasm: implement the //go:wasmimport directive

It is implemented upstream and looks pretty stable.
---
 compiler/symbol.go                |  9 +++++++++
 src/runtime/runtime_tinygowasm.go |  6 ++----
 src/runtime/runtime_wasm_wasi.go  | 12 ++++--------
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/compiler/symbol.go b/compiler/symbol.go
index 6469ba16..feff10ba 100644
--- a/compiler/symbol.go
+++ b/compiler/symbol.go
@@ -288,6 +288,15 @@ func (info *functionInfo) parsePragmas(f *ssa.Function) {
 					continue
 				}
 				info.module = parts[1]
+			case "//go:wasmimport":
+				// Import a WebAssembly function, for example a WASI function.
+				// For details, see: https://github.com/golang/go/issues/38248
+				if len(parts) != 3 {
+					continue
+				}
+				info.exported = true
+				info.module = parts[1]
+				info.importName = parts[2]
 			case "//go:inline":
 				info.inline = inlineHint
 			case "//go:noinline":
diff --git a/src/runtime/runtime_tinygowasm.go b/src/runtime/runtime_tinygowasm.go
index 95c02a52..bd8adea6 100644
--- a/src/runtime/runtime_tinygowasm.go
+++ b/src/runtime/runtime_tinygowasm.go
@@ -12,15 +12,13 @@ type __wasi_iovec_t struct {
 	bufLen uint
 }
 
-//go:wasm-module wasi_snapshot_preview1
-//export fd_write
+//go:wasmimport wasi_snapshot_preview1 fd_write
 func fd_write(id uint32, iovs *__wasi_iovec_t, iovs_len uint, nwritten *uint) (errno uint)
 
 // See:
 // https://github.com/WebAssembly/WASI/blob/main/phases/snapshot/docs.md#-proc_exitrval-exitcode
 //
-//go:wasm-module wasi_snapshot_preview1
-//export proc_exit
+//go:wasmimport wasi_snapshot_preview1 proc_exit
 func proc_exit(exitcode uint32)
 
 const (
diff --git a/src/runtime/runtime_wasm_wasi.go b/src/runtime/runtime_wasm_wasi.go
index 42869ba7..aec27e4c 100644
--- a/src/runtime/runtime_wasm_wasi.go
+++ b/src/runtime/runtime_wasm_wasi.go
@@ -101,20 +101,16 @@ func ticks() timeUnit {
 
 // Implementations of WASI APIs
 
-//go:wasm-module wasi_snapshot_preview1
-//export args_get
+//go:wasmimport wasi_snapshot_preview1 args_get
 func args_get(argv *unsafe.Pointer, argv_buf unsafe.Pointer) (errno uint16)
 
-//go:wasm-module wasi_snapshot_preview1
-//export args_sizes_get
+//go:wasmimport wasi_snapshot_preview1 args_sizes_get
 func args_sizes_get(argc *uint32, argv_buf_size *uint32) (errno uint16)
 
-//go:wasm-module wasi_snapshot_preview1
-//export clock_time_get
+//go:wasmimport wasi_snapshot_preview1 clock_time_get
 func clock_time_get(clockid uint32, precision uint64, time *uint64) (errno uint16)
 
-//go:wasm-module wasi_snapshot_preview1
-//export poll_oneoff
+//go:wasmimport wasi_snapshot_preview1 poll_oneoff
 func poll_oneoff(in *__wasi_subscription_t, out *__wasi_event_t, nsubscriptions uint32, nevents *uint32) (errno uint16)
 
 type __wasi_eventtype_t = uint8