feat(asm): emit GOOBJ objects that link directly with the Go toolchain

Assisted-by: Qwen 3.8 Max Preview

asm/link.go

@@ -28,13 +28,26 @@ type Image struct {
 
 // FuncLayout describes one assembled function within an Image.
 type FuncLayout struct {
-	Name   string
-	Pkg    string // explicit package prefix ("" = the current package)
-	Static bool   // the <> marker: file-local, not exported
-	Offset int    // start offset within the image (== offset within Code)
-	Size   int
-	Labels map[string]int // local labels, function-relative
-	Relocs []Reloc        // static-symbol references, in emission order
+	Name    string
+	Pkg     string // explicit package prefix ("" = the current package)
+	Static  bool   // the <> marker: file-local, not exported
+	Offset  int    // start offset within the image (== offset within Code)
+	Size    int
+	Args    int            // declared argument/result area (the TEXT size suffix)
+	Frame   int            // local frame size (the TEXT $framesize)
+	NoSplit bool           // the NOSPLIT flag
+	SPWrite bool           // the SPWRITE flag: writes an arbitrary value to SP
+	Line    int            // source line of the TEXT directive
+	Labels  map[string]int // local labels, function-relative
+	Relocs  []Reloc        // static-symbol references, in emission order
+	Spadj   []SpadjStep    // stack-adjustment boundaries, ascending by PC
+}
+
+// SpadjStep is one stack-adjustment boundary: Value is the SP delta from the
+// entry state in effect from PC (function-relative) until the next step.
+type SpadjStep struct {
+	PC    int
+	Value int
 }
 
 // Reloc is one static-symbol reference within a function body: the disp32
@@ -57,6 +70,8 @@ type DataSymbol struct {
 	Offset int    // byte offset within Data
 	Size   int
 	Static bool // the <> marker: file-local, not exported
+	Rodata bool // the RODATA flag: read-only data
+	Dupok  bool // the DUPOK flag: duplicate-OK
 }
 
 // Bytes returns the whole image: code, then data.
@@ -95,18 +110,33 @@ func AssembleFile(f *ast.File) (*Image, error) {
 		if !ok {
 			continue
 		}
-		code, patches, labels, err := assemble(t, link)
+		code, patches, labels, steps, err := assemble(t, link)
 		if err != nil {
 			return nil, fmt.Errorf("%s: %w", t.Name.Name, err)
 		}
-		img.Funcs = append(img.Funcs, FuncLayout{
+		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
+			}
+		}
+		for _, s := range steps {
+			fl.Spadj = append(fl.Spadj, SpadjStep{PC: s.pc, Value: s.value})
+		}
+		img.Funcs = append(img.Funcs, fl)
 		img.Code = append(img.Code, code...)
 		funcs = append(funcs, asmFunc{name: t.Name.Name, patches: patches})
 	}
@@ -124,6 +154,8 @@ func AssembleFile(f *ast.File) (*Image, error) {
 			Offset: len(img.Data),
 			Size:   len(d.buf),
 			Static: d.static,
+			Rodata: d.rodata,
+			Dupok:  d.dupok,
 		})
 		img.Data = append(img.Data, d.buf...)
 	}
@@ -163,6 +195,8 @@ type dataSym struct {
 	pkg    string
 	buf    []byte
 	static bool
+	rodata bool
+	dupok  bool
 }
 
 // collectData gathers the file's static symbols (GLOBL) and their initial
@@ -185,12 +219,28 @@ func collectData(f *ast.File) ([]dataSym, error) {
 				size = int(dd.Size.Imm.Val)
 			}
 			index[name] = len(syms)
-			syms = append(syms, dataSym{
+			ds := dataSym{
 				name:   name,
 				pkg:    dd.Name.Pkg,
 				buf:    make([]byte, size),
 				static: dd.Name.Static,
-			})
+			}
+			for _, f := range dd.Flags {
+				switch f {
+				case "RODATA":
+					ds.rodata = true
+				case "DUPOK":
+					ds.dupok = true
+				case "1":
+					ds.dupok = true
+				case "8":
+					ds.rodata = true
+				case "9":
+					ds.dupok = true
+					ds.rodata = true
+				}
+			}
+			syms = append(syms, ds)
 
 		case *ast.Data:
 			if dd.Name == nil || dd.Name.Pseudo != "SB" {
@@ -230,3 +280,19 @@ func collectData(f *ast.File) ([]dataSym, error) {
 func align16(n int) int {
 	return (n + 15) &^ 15
 }
+
+// frameSize returns the local frame size declared on the TEXT directive.
+func frameSize(t *ast.Text) int {
+	if t.Frame != nil && t.Frame.Imm.HasVal {
+		return int(t.Frame.Imm.Val)
+	}
+	return 0
+}
+
+// argsSize returns the argument/result area declared on the TEXT directive.
+func argsSize(t *ast.Text) int {
+	if t.Args != nil && t.Args.Imm.HasVal {
+		return int(t.Args.Imm.Val)
+	}
+	return 0
+}