chore: go mod vendor / tidy

vendor/github.com/mmcloughlin/avo/printer/goasm.go

@@ -0,0 +1,192 @@
+package printer
+
+import (
+	"strconv"
+	"strings"
+
+	"github.com/mmcloughlin/avo/buildtags"
+	"github.com/mmcloughlin/avo/internal/prnt"
+	"github.com/mmcloughlin/avo/ir"
+	"github.com/mmcloughlin/avo/operand"
+)
+
+// dot is the pesky unicode dot used in Go assembly.
+const dot = "\u00b7"
+
+type goasm struct {
+	cfg Config
+	prnt.Generator
+
+	instructions []*ir.Instruction
+	clear        bool
+}
+
+// NewGoAsm constructs a printer for writing Go assembly files.
+func NewGoAsm(cfg Config) Printer {
+	return &goasm{cfg: cfg}
+}
+
+func (p *goasm) Print(f *ir.File) ([]byte, error) {
+	p.header(f)
+	for _, s := range f.Sections {
+		switch s := s.(type) {
+		case *ir.Function:
+			p.function(s)
+		case *ir.Global:
+			p.global(s)
+		default:
+			panic("unknown section type")
+		}
+	}
+	return p.Result()
+}
+
+func (p *goasm) header(f *ir.File) {
+	p.Comment(p.cfg.GeneratedWarning())
+
+	if len(f.Constraints) > 0 {
+		constraints, err := buildtags.Format(f.Constraints)
+		if err != nil {
+			p.AddError(err)
+		}
+		p.NL()
+		p.Printf(constraints)
+	}
+
+	if len(f.Includes) > 0 {
+		p.NL()
+		p.includes(f.Includes)
+	}
+}
+
+func (p *goasm) includes(paths []string) {
+	for _, path := range paths {
+		p.Printf("#include \"%s\"\n", path)
+	}
+}
+
+func (p *goasm) function(f *ir.Function) {
+	p.NL()
+	p.Comment(f.Stub())
+
+	if len(f.ISA) > 0 {
+		p.Comment("Requires: " + strings.Join(f.ISA, ", "))
+	}
+
+	// Reference: https://github.com/golang/go/blob/b115207baf6c2decc3820ada4574ef4e5ad940ec/src/cmd/internal/obj/util.go#L166-L176
+	//
+	//		if p.As == ATEXT {
+	//			// If there are attributes, print them. Otherwise, skip the comma.
+	//			// In short, print one of these two:
+	//			// TEXT	foo(SB), DUPOK|NOSPLIT, $0
+	//			// TEXT	foo(SB), $0
+	//			s := p.From.Sym.Attribute.TextAttrString()
+	//			if s != "" {
+	//				fmt.Fprintf(&buf, "%s%s", sep, s)
+	//				sep = ", "
+	//			}
+	//		}
+	//
+	p.Printf("TEXT %s%s(SB)", dot, f.Name)
+	if f.Attributes != 0 {
+		p.Printf(", %s", f.Attributes.Asm())
+	}
+	p.Printf(", %s\n", textsize(f))
+
+	p.clear = true
+	for _, node := range f.Nodes {
+		switch n := node.(type) {
+		case *ir.Instruction:
+			p.instruction(n)
+			if n.IsTerminal || n.IsUnconditionalBranch() {
+				p.flush()
+			}
+		case ir.Label:
+			p.flush()
+			p.ensureclear()
+			p.Printf("%s:\n", n)
+		case *ir.Comment:
+			p.flush()
+			p.ensureclear()
+			for _, line := range n.Lines {
+				p.Printf("\t// %s\n", line)
+			}
+		default:
+			panic("unexpected node type")
+		}
+	}
+	p.flush()
+}
+
+func (p *goasm) instruction(i *ir.Instruction) {
+	p.instructions = append(p.instructions, i)
+	p.clear = false
+}
+
+func (p *goasm) flush() {
+	if len(p.instructions) == 0 {
+		return
+	}
+
+	// Determine instruction width. Instructions with no operands are not
+	// considered in this calculation.
+	width := 0
+	for _, i := range p.instructions {
+		opcode := i.OpcodeWithSuffixes()
+		if len(i.Operands) > 0 && len(opcode) > width {
+			width = len(opcode)
+		}
+	}
+
+	// Output instruction block.
+	for _, i := range p.instructions {
+		if len(i.Operands) > 0 {
+			p.Printf("\t%-*s%s\n", width+1, i.OpcodeWithSuffixes(), joinOperands(i.Operands))
+		} else {
+			p.Printf("\t%s\n", i.OpcodeWithSuffixes())
+		}
+	}
+
+	p.instructions = nil
+}
+
+func (p *goasm) ensureclear() {
+	if !p.clear {
+		p.NL()
+		p.clear = true
+	}
+}
+
+func (p *goasm) global(g *ir.Global) {
+	p.NL()
+	for _, d := range g.Data {
+		a := operand.NewDataAddr(g.Symbol, d.Offset)
+		p.Printf("DATA %s/%d, %s\n", a.Asm(), d.Value.Bytes(), d.Value.Asm())
+	}
+	p.Printf("GLOBL %s(SB), %s, $%d\n", g.Symbol, g.Attributes.Asm(), g.Size)
+}
+
+func textsize(f *ir.Function) string {
+	// Reference: https://github.com/golang/go/blob/b115207baf6c2decc3820ada4574ef4e5ad940ec/src/cmd/internal/obj/util.go#L260-L265
+	//
+	//		case TYPE_TEXTSIZE:
+	//			if a.Val.(int32) == objabi.ArgsSizeUnknown {
+	//				str = fmt.Sprintf("$%d", a.Offset)
+	//			} else {
+	//				str = fmt.Sprintf("$%d-%d", a.Offset, a.Val.(int32))
+	//			}
+	//
+	s := "$" + strconv.Itoa(f.FrameBytes())
+	if argsize := f.ArgumentBytes(); argsize > 0 {
+		return s + "-" + strconv.Itoa(argsize)
+	}
+	return s
+}
+
+func joinOperands(operands []operand.Op) string {
+	asm := make([]string, len(operands))
+	for i, op := range operands {
+		asm[i] = op.Asm()
+	}
+	return strings.Join(asm, ", ")
+}