first pass at DATA sections

ast.go

@@ -1,6 +1,8 @@
 package avo
 
 import (
+	"errors"
+
 	"github.com/mmcloughlin/avo/gotypes"
 	"github.com/mmcloughlin/avo/operand"
 	"github.com/mmcloughlin/avo/reg"
@@ -99,6 +101,10 @@ func NewFile() *File {
 	return &File{}
 }
 
+func (f *File) AddSection(s Section) {
+	f.Sections = append(f.Sections, s)
+}
+
 func (f *File) Functions() []*Function {
 	var fns []*Function
 	for _, s := range f.Sections {
@@ -124,7 +130,7 @@ type Function struct {
 	Allocation reg.Allocation
 }
 
-func (f Function) section() {}
+func (f *Function) section() {}
 
 func NewFunction(name string) *Function {
 	return &Function{
@@ -181,3 +187,77 @@ func (f *Function) FrameBytes() int {
 func (f *Function) ArgumentBytes() int {
 	return f.Signature.Bytes()
 }
+
+type Datum struct {
+	Offset int
+	Value  operand.Constant
+}
+
+func NewDatum(offset int, v operand.Constant) Datum {
+	return Datum{
+		Offset: offset,
+		Value:  v,
+	}
+}
+
+// Interval returns the range of bytes this datum will occupy within its section.
+func (d Datum) Interval() (int, int) {
+	return d.Offset, d.Offset + d.Value.Bytes()
+}
+
+func (d Datum) Overlaps(other Datum) bool {
+	s, e := d.Interval()
+	so, eo := other.Interval()
+	return !(eo <= s || e <= so)
+}
+
+type Global struct {
+	Symbol operand.Symbol
+	Data   []Datum
+	Size   int
+}
+
+func NewGlobal(sym operand.Symbol) *Global {
+	return &Global{
+		Symbol: sym,
+	}
+}
+
+func NewStaticGlobal(name string) *Global {
+	return NewGlobal(operand.NewStaticSymbol(name))
+}
+
+func (g *Global) section() {}
+
+func (g *Global) Base() operand.Mem {
+	return operand.NewDataAddr(g.Symbol, 0)
+}
+
+func (g *Global) Grow(size int) {
+	if g.Size < size {
+		g.Size = size
+	}
+}
+
+func (g *Global) AddDatum(d Datum) error {
+	for _, other := range g.Data {
+		if d.Overlaps(other) {
+			return errors.New("overlaps existing datum")
+		}
+	}
+	g.add(d)
+	return nil
+}
+
+func (g *Global) Append(v operand.Constant) {
+	g.add(Datum{
+		Offset: g.Size,
+		Value:  v,
+	})
+}
+
+func (g *Global) add(d Datum) {
+	_, end := d.Interval()
+	g.Grow(end)
+	g.Data = append(g.Data, d)
+}

build/context.go

@@ -15,6 +15,7 @@ type Context struct {
 	pkg      *packages.Package
 	file     *avo.File
 	function *avo.Function
+	global   *avo.Global
 	errs     []error
 	reg.Collection
 }
@@ -47,7 +48,7 @@ func (c *Context) Package(path string) {
 
 func (c *Context) Function(name string) {
 	c.function = avo.NewFunction(name)
-	c.file.Sections = append(c.file.Sections, c.function)
+	c.file.AddSection(c.function)
 }
 
 func (c *Context) Signature(s *gotypes.Signature) {
@@ -92,6 +93,30 @@ func (c *Context) activefunc() *avo.Function {
 
 //go:generate avogen -output zinstructions.go build
 
+func (c *Context) StaticGlobal(name string) operand.Mem {
+	c.global = avo.NewStaticGlobal(name)
+	c.file.AddSection(c.global)
+	return c.global.Base()
+}
+
+func (c *Context) AddDatum(offset int, v operand.Constant) {
+	if err := c.activeglobal().AddDatum(avo.NewDatum(offset, v)); err != nil {
+		c.AddError(err)
+	}
+}
+
+func (c *Context) AppendDatum(v operand.Constant) {
+	c.activeglobal().Append(v)
+}
+
+func (c *Context) activeglobal() *avo.Global {
+	if c.global == nil {
+		c.AddErrorMessage("no active global")
+		return avo.NewStaticGlobal("")
+	}
+	return c.global
+}
+
 func (c *Context) AddError(err error) {
 	c.errs = append(c.errs, err)
 }

build/global.go

@@ -24,6 +24,14 @@ func TEXT(name, signature string) {
 
 func LABEL(name string) { ctx.Label(avo.Label(name)) }
 
+func GLOBL(name string) operand.Mem {
+	return ctx.StaticGlobal(name)
+}
+
+func DATA(offset int, v operand.Constant) {
+	ctx.AddDatum(offset, v)
+}
+
 var flags = NewFlags(flag.CommandLine)
 
 func Generate() {

examples/data/asm.go

@@ -0,0 +1,34 @@
+// +build ignore
+
+package main
+
+import (
+	"math"
+
+	. "github.com/mmcloughlin/avo/build"
+	. "github.com/mmcloughlin/avo/operand"
+)
+
+func main() {
+	bytes := GLOBL("bytes")
+	DATA(0, U64(0x0011223344556677))
+	DATA(8, String("strconst"))
+	DATA(16, F32(math.Pi))
+	DATA(24, F64(math.Pi))
+	DATA(32, U32(0x00112233))
+	DATA(36, U16(0x4455))
+	DATA(38, U8(0x66))
+	DATA(39, U8(0x77))
+
+	// TEXT ·DataAt(SB),0,$0-9
+	TEXT("DataAt", "func(i int) byte")
+	i := Load(Param("i"), GP64v()) // MOVQ	i+0(FP), AX
+	ptr := Mem{Base: GP64v()}
+	LEAQ(bytes, ptr.Base) // LEAQ	b<>+0x00(SB), BX
+	b := GP8v()
+	MOVB(ptr.Idx(i, 1), b)   // MOVB	0(BX)(AX*1), CL
+	Store(b, ReturnIndex(0)) // MOVB	CL, ret+8(FP)
+	RET()                    // RET
+
+	Generate()
+}

examples/data/data.s

@@ -0,0 +1,21 @@
+// Code generated by command: go run asm.go -out data.s -stubs stub.go. DO NOT EDIT.
+
+#include "textflag.h"
+
+DATA bytes<>(SB)/8, $0x0011223344556677
+DATA bytes<>+8(SB)/8, $"strconst"
+DATA bytes<>+16(SB)/4, $(3.1415927)
+DATA bytes<>+24(SB)/8, $(3.141592653589793)
+DATA bytes<>+32(SB)/4, $0x00112233
+DATA bytes<>+36(SB)/2, $0x4455
+DATA bytes<>+38(SB)/1, $0x66
+DATA bytes<>+39(SB)/1, $0x77
+GLOBL ·bytes<>(SB), RODATA, $40
+
+// func DataAt(i int) byte
+TEXT ·DataAt(SB),0,$0-9
+	MOVQ	i(FP), AX
+	LEAQ	bytes<>(SB), CX
+	MOVB	(CX)(AX*1), AL
+	MOVB	AL, ret+8(FP)
+	RET

examples/data/data_test.go

@@ -0,0 +1,29 @@
+package data
+
+import (
+	"encoding/binary"
+	"math"
+	"testing"
+)
+
+//go:generate go run asm.go -out data.s -stubs stub.go
+
+func TestDataAt(t *testing.T) {
+	order := binary.LittleEndian
+	expect := make([]byte, 40)
+	order.PutUint64(expect[0:], 0x0011223344556677)         // DATA(0, U64(0x0011223344556677))
+	copy(expect[8:], []byte("strconst"))                    // DATA(8, String("strconst"))
+	order.PutUint32(expect[16:], math.Float32bits(math.Pi)) // DATA(16, F32(math.Pi))
+	order.PutUint64(expect[24:], math.Float64bits(math.Pi)) // DATA(24, F64(math.Pi))
+	order.PutUint32(expect[32:], 0x00112233)                // DATA(32, U32(0x00112233))
+	order.PutUint16(expect[36:], 0x4455)                    // DATA(36, U16(0x4455))
+	expect[38] = 0x66                                       // DATA(38, U8(0x66))
+	expect[39] = 0x77                                       // DATA(39, U8(0x77))
+
+	for i, e := range expect {
+		b := DataAt(i)
+		if b != e {
+			t.Errorf("DataAt(%d) = %#02x; expected %#02x", i, b, e)
+		}
+	}
+}

examples/data/stub.go

@@ -0,0 +1,5 @@
+// Code generated by command: go run asm.go -out data.s -stubs stub.go. DO NOT EDIT.
+
+package data
+
+func DataAt(i int) byte

examples/sha1/asm.go

@@ -15,16 +15,16 @@ func main() {
 
 	// Store message values on the stack.
 	w := AllocLocal(64)
-	W := func(r int) Mem { return w.Idx((r % 16) * 4) }
+	W := func(r int) Mem { return w.Offset((r % 16) * 4) }
 
 	// Load initial hash.
 	h0, h1, h2, h3, h4 := GP32v(), GP32v(), GP32v(), GP32v(), GP32v()
 
-	MOVL(h.Idx(0), h0)
+	MOVL(h.Offset(0), h0)
-	MOVL(h.Idx(4), h1)
+	MOVL(h.Offset(4), h1)
-	MOVL(h.Idx(8), h2)
+	MOVL(h.Offset(8), h2)
-	MOVL(h.Idx(12), h3)
+	MOVL(h.Offset(12), h3)
-	MOVL(h.Idx(16), h4)
+	MOVL(h.Offset(16), h4)
 
 	// Initialize registers.
 	a, b, c, d, e := GP32v(), GP32v(), GP32v(), GP32v(), GP32v()
@@ -52,7 +52,7 @@ func main() {
 		// Load message value.
 		u := GP32v()
 		if r < 16 {
-			MOVL(m.Idx(4*r), u)
+			MOVL(m.Offset(4*r), u)
 			BSWAPL(u)
 		} else {
 			MOVL(W(r-3), u)
@@ -85,11 +85,11 @@ func main() {
 	ADDL(e, h4)
 
 	// Store results back.
-	MOVL(h0, h.Idx(0))
+	MOVL(h0, h.Offset(0))
-	MOVL(h1, h.Idx(4))
+	MOVL(h1, h.Offset(4))
-	MOVL(h2, h.Idx(8))
+	MOVL(h2, h.Offset(8))
-	MOVL(h3, h.Idx(12))
+	MOVL(h3, h.Offset(12))
-	MOVL(h4, h.Idx(16))
+	MOVL(h4, h.Offset(16))
 	RET()
 
 	Generate()

operand/types.go

@@ -15,6 +15,10 @@ type Symbol struct {
 	Static bool
 }
 
+func NewStaticSymbol(name string) Symbol {
+	return Symbol{Name: name, Static: true}
+}
+
 func (s Symbol) String() string {
 	n := s.Name
 	if s.Static {
@@ -51,12 +55,27 @@ func NewStackAddr(offset int) Mem {
 	}
 }
 
-func (m Mem) Idx(idx int) Mem {
+func NewDataAddr(sym Symbol, offset int) Mem {
+	return Mem{
+		Symbol: sym,
+		Disp:   offset,
+		Base:   reg.StaticBase,
+	}
+}
+
+func (m Mem) Offset(idx int) Mem {
 	a := m
 	a.Disp += idx
 	return a
 }
 
+func (m Mem) Idx(r reg.Register, s uint8) Mem {
+	a := m
+	a.Index = r
+	a.Scale = s
+	return a
+}
+
 func (m Mem) Asm() string {
 	a := m.Symbol.String()
 	if m.Disp != 0 {

operand/types_test.go

@@ -42,6 +42,8 @@ func TestMemAsm(t *testing.T) {
 		{Mem{Symbol: Symbol{Name: "foo"}, Base: reg.StaticBase, Disp: -7}, "foo-7(SB)"},
 		{Mem{Symbol: Symbol{Name: "bar", Static: true}, Base: reg.StaticBase, Disp: 4, Index: reg.R11, Scale: 4}, "bar<>+4(SB)(R11*4)"},
 		{NewParamAddr("param", 16), "param+16(FP)"},
+		{NewStackAddr(42), "42(SP)"},
+		{NewDataAddr(Symbol{Name: "data", Static: true}, 13), "data<>+13(SB)"},
 	}
 	for _, c := range cases {
 		got := c.Mem.Asm()

printer/goasm.go

@@ -26,6 +26,8 @@ func (p *goasm) Print(f *avo.File) ([]byte, error) {
 		switch s := s.(type) {
 		case *avo.Function:
 			p.function(s)
+		case *avo.Global:
+			p.global(s)
 		default:
 			panic("unknown section type")
 		}
@@ -64,6 +66,16 @@ func (p *goasm) function(f *avo.Function) {
 	}
 }
 
+func (p *goasm) global(g *avo.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())
+	}
+	// TODO(mbm): replace hardcoded RODATA with an attributes list
+	p.Printf("GLOBL %s%s(SB), RODATA, $%d\n", dot, g.Symbol, g.Size)
+}
+
 func joinOperands(operands []operand.Op) string {
 	asm := make([]string, len(operands))
 	for i, op := range operands {