sys, pkg/compiler: move padding computation to compiler

This makes types constant during execution, everything is precomputed.

9 files changed, 28 insertions, 30 deletions

diff --git a/prog/analysis.go b/prog/analysis.go
index 81dc94956..2edd8f7dd 100644
--- a/prog/analysis.go
+++ b/prog/analysis.go
@@ -52,13 +52,13 @@ func (s *state) analyze(c *Call) {
 	foreachArgArray(&c.Args, c.Ret, func(arg, base Arg, _ *[]Arg) {
 		switch typ := arg.Type().(type) {
 		case *sys.ResourceType:
-			if arg.Type().Dir() != sys.DirIn {
+			if typ.Dir() != sys.DirIn {
 				s.resources[typ.Desc.Name] = append(s.resources[typ.Desc.Name], arg)
 				// TODO: negative PIDs and add them as well (that's process groups).
 			}
 		case *sys.BufferType:
 			a := arg.(*DataArg)
-			if a.Type().Dir() != sys.DirOut && len(a.Data) != 0 {
+			if typ.Dir() != sys.DirOut && len(a.Data) != 0 {
 				switch typ.Kind {
 				case sys.BufferString:
 					s.strings[string(a.Data)] = true
diff --git a/prog/encoding.go b/prog/encoding.go
index 8ba634d12..d31d0bb62 100644
--- a/prog/encoding.go
+++ b/prog/encoding.go
@@ -346,7 +346,7 @@ func parseArg(typ sys.Type, p *parser, vars map[string]Arg) (Arg, error) {
 		name := p.Ident()
 		p.Parse('=')
 		var optType sys.Type
-		for _, t2 := range t1.Options {
+		for _, t2 := range t1.Fields {
 			if name == t2.FieldName() {
 				optType = t2
 				break
diff --git a/prog/encodingexec_test.go b/prog/encodingexec_test.go
index ec8d74bba..bc9e1d705 100644
--- a/prog/encodingexec_test.go
+++ b/prog/encodingexec_test.go
@@ -133,7 +133,7 @@ func TestSerializeForExec(t *testing.T) {
 				instrCopyin, dataOffset + 16, argConst, 2, 0x44, 0, 0,
 				instrCopyin, dataOffset + 18, argConst, 2, 0x45, 0, 0,
 				instrCopyin, dataOffset + 20, argConst, 2, 0x46, 0, 0,
-				instrCopyin, dataOffset + 24, argConst, 1, 0x47, 0, 0,
+				instrCopyin, dataOffset + 22, argConst, 1, 0x47, 0, 0,
 				callID("syz_test$align5"), 1, argConst, ptrSize, dataOffset, 0, 0,
 				instrEOF,
 			},
diff --git a/prog/hints_test.go b/prog/hints_test.go
index 0490e6d6f..945f9bcd9 100644
--- a/prog/hints_test.go
+++ b/prog/hints_test.go
@@ -158,7 +158,7 @@ func TestHintsCheckDataArg(t *testing.T) {
 			res := make(map[string]bool)
 			// Whatever type here. It's just needed to pass the
 			// dataArg.Type().Dir() == sys.DirIn check.
-			typ := sys.ArrayType{sys.TypeCommon{"", "", sys.DirIn, false}, nil, 0, 0, 0}
+			typ := sys.ArrayType{sys.TypeCommon{"", "", 0, sys.DirIn, false}, nil, 0, 0, 0}
 			argCommon := ArgCommon{&typ}
 			dataArg := &DataArg{argCommon, []byte(test.in)}
 			checkDataArg(dataArg, test.comps, func(arg Arg) {
diff --git a/prog/mutation.go b/prog/mutation.go
index a6b39385c..780b5882e 100644
--- a/prog/mutation.go
+++ b/prog/mutation.go
@@ -112,11 +112,9 @@ func (p *Prog) Mutate(rs rand.Source, ncalls int, ct *ChoiceTable, corpus []*Pro
 						a.Data = mutateData(r, data, minLen, maxLen)
 					case sys.BufferString:
 						if r.bin() {
-							var minLen uint64
-							maxLen := ^uint64(0)
-							if t.Length != 0 {
-								minLen = t.Length
-								maxLen = t.Length
+							minLen, maxLen := uint64(0), ^uint64(0)
+							if t.TypeSize != 0 {
+								minLen, maxLen = t.TypeSize, t.TypeSize
 							}
 							a.Data = mutateData(r, append([]byte{}, a.Data...), minLen, maxLen)
 						} else {
@@ -191,10 +189,10 @@ func (p *Prog) Mutate(rs rand.Source, ncalls int, ct *ChoiceTable, corpus []*Pro
 					}
 				case *sys.UnionType:
 					a := arg.(*UnionArg)
-					optType := t.Options[r.Intn(len(t.Options))]
+					optType := t.Fields[r.Intn(len(t.Fields))]
 					maxIters := 1000
 					for i := 0; optType.FieldName() == a.OptionType.FieldName(); i++ {
-						optType = t.Options[r.Intn(len(t.Options))]
+						optType = t.Fields[r.Intn(len(t.Fields))]
 						if i >= maxIters {
 							panic(fmt.Sprintf("couldn't generate a different union option after %v iterations, type: %+v", maxIters, t))
 						}
diff --git a/prog/prog.go b/prog/prog.go
index edb5c9e2d..18ff1ddf8 100644
--- a/prog/prog.go
+++ b/prog/prog.go
@@ -102,7 +102,11 @@ type GroupArg struct {
 }
 
 func (arg *GroupArg) Size() uint64 {
-	switch typ := (*arg).Type().(type) {
+	typ0 := arg.Type()
+	if !typ0.Varlen() {
+		return typ0.Size()
+	}
+	switch typ := typ0.(type) {
 	case *sys.StructType:
 		var size uint64
 		for _, fld := range arg.Inner {
@@ -110,19 +114,14 @@ func (arg *GroupArg) Size() uint64 {
 				size += fld.Size()
 			}
 		}
-		align := typ.Align()
-		if size%align != 0 {
-			if typ.Varlen() {
-				size += align - size%align
-			} else {
-				panic(fmt.Sprintf("struct %+v with type %+v has static size %v, which isn't aligned to %v", arg, typ, size, align))
-			}
+		if typ.AlignAttr != 0 && size%typ.AlignAttr != 0 {
+			size += typ.AlignAttr - size%typ.AlignAttr
 		}
 		return size
 	case *sys.ArrayType:
 		var size uint64
-		for _, in := range arg.Inner {
-			size += in.Size()
+		for _, elem := range arg.Inner {
+			size += elem.Size()
 		}
 		return size
 	default:
@@ -274,8 +273,8 @@ func defaultArg(t sys.Type) Arg {
 		return resultArg(t, nil, typ.Desc.Type.Default())
 	case *sys.BufferType:
 		var data []byte
-		if typ.Kind == sys.BufferString && typ.Length != 0 {
-			data = make([]byte, typ.Length)
+		if typ.Kind == sys.BufferString && typ.TypeSize != 0 {
+			data = make([]byte, typ.TypeSize)
 		}
 		return dataArg(t, data)
 	case *sys.ArrayType:
@@ -287,7 +286,7 @@ func defaultArg(t sys.Type) Arg {
 		}
 		return groupArg(t, inner)
 	case *sys.UnionType:
-		return unionArg(t, defaultArg(typ.Options[0]), typ.Options[0])
+		return unionArg(t, defaultArg(typ.Fields[0]), typ.Fields[0])
 	case *sys.VmaType:
 		return pointerArg(t, 0, 0, 1, nil)
 	case *sys.PtrType:
diff --git a/prog/rand.go b/prog/rand.go
index ea89dd33d..516aa2831 100644
--- a/prog/rand.go
+++ b/prog/rand.go
@@ -755,7 +755,7 @@ func (r *randGen) generateArg(s *state, typ sys.Type) (arg Arg, calls []*Call) {
 		group := groupArg(a, args)
 		return group, calls
 	case *sys.UnionType:
-		optType := a.Options[r.Intn(len(a.Options))]
+		optType := a.Fields[r.Intn(len(a.Fields))]
 		opt, calls := r.generateArg(s, optType)
 		return unionArg(a, opt, optType), calls
 	case *sys.PtrType:
diff --git a/prog/size_test.go b/prog/size_test.go
index d206a0faa..c72e5283f 100644
--- a/prog/size_test.go
+++ b/prog/size_test.go
@@ -70,7 +70,7 @@ func TestAssignSize(t *testing.T) {
 		},
 		{
 			"syz_test$length8(&(0x7f000001f000)={0x00, {0xff, 0x0, 0x00, [0xff, 0xff, 0xff]}, [{0xff, 0x0, 0x00, [0xff, 0xff, 0xff]}], 0x00, 0x0, [0xff, 0xff]})",
-			"syz_test$length8(&(0x7f000001f000)={0x38, {0xff, 0x1, 0x10, [0xff, 0xff, 0xff]}, [{0xff, 0x1, 0x10, [0xff, 0xff, 0xff]}], 0x10, 0x1, [0xff, 0xff]})",
+			"syz_test$length8(&(0x7f000001f000)={0x32, {0xff, 0x1, 0x10, [0xff, 0xff, 0xff]}, [{0xff, 0x1, 0x10, [0xff, 0xff, 0xff]}], 0x10, 0x1, [0xff, 0xff]})",
 		},
 		{
 			"syz_test$length9(&(0x7f000001f000)={&(0x7f0000000000/0x5000)=nil, 0x0000})",
diff --git a/prog/validation.go b/prog/validation.go
index b3c4ad3e6..7b5f02e1c 100644
--- a/prog/validation.go
+++ b/prog/validation.go
@@ -125,8 +125,9 @@ func (c *Call) validate(ctx *validCtx) error {
 			case *DataArg:
 				switch typ1.Kind {
 				case sys.BufferString:
-					if typ1.Length != 0 && len(a.Data) != int(typ1.Length) {
-						return fmt.Errorf("syscall %v: string arg '%v' has size %v, which should be %v", c.Meta.Name, a.Type().Name(), len(a.Data), typ1.Length)
+					if typ1.TypeSize != 0 && uint64(len(a.Data)) != typ1.TypeSize {
+						return fmt.Errorf("syscall %v: string arg '%v' has size %v, which should be %v",
+							c.Meta.Name, a.Type().Name(), len(a.Data), typ1.TypeSize)
 					}
 				}
 			default:
@@ -210,7 +211,7 @@ func (c *Call) validate(ctx *validCtx) error {
 				return fmt.Errorf("syscall %v: union arg '%v' has bad type", c.Meta.Name, a.Type().Name())
 			}
 			found := false
-			for _, typ2 := range typ1.Options {
+			for _, typ2 := range typ1.Fields {
 				if a.OptionType.Name() == typ2.Name() {
 					found = true
 					break