122 lines
2.7 KiB
Go
122 lines
2.7 KiB
Go
package printer
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import (
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"strconv"
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"strings"
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"github.com/mmcloughlin/avo"
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"github.com/mmcloughlin/avo/internal/prnt"
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"github.com/mmcloughlin/avo/operand"
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)
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// dot is the pesky unicode dot used in Go assembly.
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const dot = "\u00b7"
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type goasm struct {
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cfg Config
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prnt.Generator
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}
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func NewGoAsm(cfg Config) Printer {
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return &goasm{cfg: cfg}
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}
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func (p *goasm) Print(f *avo.File) ([]byte, error) {
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p.header()
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for _, s := range f.Sections {
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switch s := s.(type) {
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case *avo.Function:
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p.function(s)
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case *avo.Global:
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p.global(s)
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default:
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panic("unknown section type")
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}
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}
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return p.Result()
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}
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func (p *goasm) header() {
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p.Comment(p.cfg.GeneratedWarning())
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p.NL()
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p.include("textflag.h")
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}
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func (p *goasm) include(path string) {
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p.Printf("#include \"%s\"\n", path)
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}
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func (p *goasm) function(f *avo.Function) {
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p.NL()
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p.Comment(f.Stub())
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// Reference: https://github.com/golang/go/blob/b115207baf6c2decc3820ada4574ef4e5ad940ec/src/cmd/internal/obj/util.go#L166-L176
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//
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// if p.As == ATEXT {
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// // If there are attributes, print them. Otherwise, skip the comma.
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// // In short, print one of these two:
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// // TEXT foo(SB), DUPOK|NOSPLIT, $0
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// // TEXT foo(SB), $0
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// s := p.From.Sym.Attribute.TextAttrString()
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// if s != "" {
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// fmt.Fprintf(&buf, "%s%s", sep, s)
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// sep = ", "
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// }
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// }
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//
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p.Printf("TEXT %s%s(SB)", dot, f.Name)
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if f.Attributes != 0 {
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p.Printf(", %s", f.Attributes.Asm())
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}
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p.Printf(", %s\n", textsize(f))
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for _, node := range f.Nodes {
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switch n := node.(type) {
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case *avo.Instruction:
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if len(n.Operands) > 0 {
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p.Printf("\t%s\t%s\n", n.Opcode, joinOperands(n.Operands))
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} else {
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p.Printf("\t%s\n", n.Opcode)
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}
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case avo.Label:
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p.Printf("%s:\n", n)
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default:
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panic("unexpected node type")
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}
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}
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}
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func (p *goasm) global(g *avo.Global) {
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p.NL()
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for _, d := range g.Data {
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a := operand.NewDataAddr(g.Symbol, d.Offset)
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p.Printf("DATA %s/%d, %s\n", a.Asm(), d.Value.Bytes(), d.Value.Asm())
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}
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p.Printf("GLOBL %s(SB), %s, $%d\n", g.Symbol, g.Attributes.Asm(), g.Size)
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}
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func textsize(f *avo.Function) string {
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// Reference: https://github.com/golang/go/blob/b115207baf6c2decc3820ada4574ef4e5ad940ec/src/cmd/internal/obj/util.go#L260-L265
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//
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// case TYPE_TEXTSIZE:
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// if a.Val.(int32) == objabi.ArgsSizeUnknown {
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// str = fmt.Sprintf("$%d", a.Offset)
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// } else {
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// str = fmt.Sprintf("$%d-%d", a.Offset, a.Val.(int32))
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// }
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//
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s := "$" + strconv.Itoa(f.FrameBytes())
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if argsize := f.ArgumentBytes(); argsize > 0 {
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return s + "-" + strconv.Itoa(argsize)
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}
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return s
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}
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func joinOperands(operands []operand.Op) string {
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asm := make([]string, len(operands))
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for i, op := range operands {
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asm[i] = op.Asm()
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}
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return strings.Join(asm, ", ")
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}
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