feat(riscv): add prologue, epilogue and frame pseudo-register support

Assisted-by: Kimi K3

asm/link.go

@@ -220,6 +220,44 @@ func AssembleFile(f *ast.File) (*Image, error) {
 	return img, nil
 }
 
+// AssembleFileRISCV assembles every TEXT function of a parsed RISC-V file.
+// It produces an Image with the function bodies laid out in source order.
+func AssembleFileRISCV(f *ast.File) (*Image, error) {
+	img := &Image{Symbols: map[string]int{}}
+	for _, d := range f.Decls {
+		t, ok := d.(*ast.Text)
+		if !ok {
+			continue
+		}
+		code, labels, err := assembleRISCV(t)
+		if err != nil {
+			return nil, fmt.Errorf("%s: %w", t.Name.Name, err)
+		}
+		fl := FuncLayout{
+			Name:   t.Name.Name,
+			Pkg:    t.Name.Pkg,
+			Static: t.Name.Static,
+			Offset: len(img.Code),
+			Size:   len(code),
+			Frame:  frameSize(t),
+			Args:   argsSize(t),
+			Line:   t.Pos().Line,
+			Labels: labels,
+		}
+		for _, f := range t.Flags {
+			switch f {
+			case "NOSPLIT":
+				fl.NoSplit = true
+			case "SPWRITE":
+				fl.SPWrite = true
+			}
+		}
+		img.Funcs = append(img.Funcs, fl)
+		img.Code = append(img.Code, code...)
+	}
+	return img, nil
+}
+
 // dataSym is one GLOBL symbol and its DATA initialiser.
 type dataSym struct {
 	name   string