all: implement wasmimport directive

[gostls13.git] / src / cmd / internal / obj / link.go

diff --git a/src/cmd/internal/obj/link.go b/src/cmd/internal/obj/link.go
index d153afbfae0f0afdf14660975603688a06fbaeb8..077562a267cca20f03bd6735da78ccb894b5d162 100644 (file)
--- a/src/cmd/internal/obj/link.go
+++ b/src/cmd/internal/obj/link.go
@@ -37,6 +37,7 @@ import (
        "cmd/internal/objabi"
        "cmd/internal/src"
        "cmd/internal/sys"
+       "encoding/binary"
        "fmt"
        "sync"
        "sync/atomic"
@@ -499,7 +500,9 @@ type FuncInfo struct {
        WrapInfo           *LSym // for wrapper, info of wrapped function
        JumpTables         []JumpTable
 
-       FuncInfoSym *LSym
+       FuncInfoSym   *LSym
+       WasmImportSym *LSym
+       WasmImport    *WasmImport
 }
 
 // JumpTable represents a table used for implementing multi-way
@@ -558,6 +561,75 @@ func (s *LSym) File() *FileInfo {
        return f
 }
 
+// WasmImport represents a WebAssembly (WASM) imported function with
+// parameters and results translated into WASM types based on the Go function
+// declaration.
+type WasmImport struct {
+       // Module holds the WASM module name specified by the //go:wasmimport
+       // directive.
+       Module string
+       // Name holds the WASM imported function name specified by the
+       // //go:wasmimport directive.
+       Name string
+       // Params holds the imported function parameter fields.
+       Params []WasmField
+       // Results holds the imported function result fields.
+       Results []WasmField
+}
+
+func (wi *WasmImport) CreateSym(ctxt *Link) *LSym {
+       var sym LSym
+
+       var b [8]byte
+       writeByte := func(x byte) {
+               sym.WriteBytes(ctxt, sym.Size, []byte{x})
+       }
+       writeUint32 := func(x uint32) {
+               binary.LittleEndian.PutUint32(b[:], x)
+               sym.WriteBytes(ctxt, sym.Size, b[:4])
+       }
+       writeInt64 := func(x int64) {
+               binary.LittleEndian.PutUint64(b[:], uint64(x))
+               sym.WriteBytes(ctxt, sym.Size, b[:])
+       }
+       writeString := func(s string) {
+               writeUint32(uint32(len(s)))
+               sym.WriteString(ctxt, sym.Size, len(s), s)
+       }
+       writeString(wi.Module)
+       writeString(wi.Name)
+       writeUint32(uint32(len(wi.Params)))
+       for _, f := range wi.Params {
+               writeByte(byte(f.Type))
+               writeInt64(f.Offset)
+       }
+       writeUint32(uint32(len(wi.Results)))
+       for _, f := range wi.Results {
+               writeByte(byte(f.Type))
+               writeInt64(f.Offset)
+       }
+
+       return &sym
+}
+
+type WasmField struct {
+       Type WasmFieldType
+       // Offset holds the frame-pointer-relative locations for Go's stack-based
+       // ABI. This is used by the src/cmd/internal/wasm package to map WASM
+       // import parameters to the Go stack in a wrapper function.
+       Offset int64
+}
+
+type WasmFieldType byte
+
+const (
+       WasmI32 WasmFieldType = iota
+       WasmI64
+       WasmF32
+       WasmF64
+       WasmPtr
+)
+
 type InlMark struct {
        // When unwinding from an instruction in an inlined body, mark
        // where we should unwind to.