all: introduce a prog.Call constructor

Create a constructor for the prog.Call type. It allows to reduce
the duplication of code now and during further changes.

7 files changed, 35 insertions, 50 deletions

diff --git a/prog/encoding.go b/prog/encoding.go
index b389fc10d..de0e324b1 100644
--- a/prog/encoding.go
+++ b/prog/encoding.go
@@ -263,11 +263,8 @@ func (p *parser) parseProg() (*Prog, error) {
 		if meta == nil {
 			return nil, fmt.Errorf("unknown syscall %v", name)
 		}
-		c := &Call{
-			Meta:    meta,
-			Ret:     MakeReturnArg(meta.Ret),
-			Comment: p.comment,
-		}
+		c := MakeCall(meta, nil)
+		c.Comment = p.comment
 		prog.Calls = append(prog.Calls, c)
 		p.Parse('(')
 		for i := 0; p.Char() != ')'; i++ {
diff --git a/prog/prog.go b/prog/prog.go
index bcc86fb02..576348085 100644
--- a/prog/prog.go
+++ b/prog/prog.go
@@ -20,6 +20,14 @@ type Call struct {
 	Comment string
 }
 
+func MakeCall(meta *Syscall, args []Arg) *Call {
+	return &Call{
+		Meta: meta,
+		Args: args,
+		Ret:  MakeReturnArg(meta.Ret),
+	}
+}
+
 type Arg interface {
 	Type() Type
 	Dir() Dir
diff --git a/prog/rand.go b/prog/rand.go
index 7ab5068cb..f36cb0822 100644
--- a/prog/rand.go
+++ b/prog/rand.go
@@ -551,10 +551,7 @@ func (r *randGen) generateParticularCall(s *state, meta *Syscall) (calls []*Call
 	if meta.Attrs.Disabled {
 		panic(fmt.Sprintf("generating disabled call %v", meta.Name))
 	}
-	c := &Call{
-		Meta: meta,
-		Ret:  MakeReturnArg(meta.Ret),
-	}
+	c := MakeCall(meta, nil)
 	c.Args, calls = r.generateArgs(s, meta.Args, DirIn)
 	r.target.assignSizesCall(c)
 	return append(calls, c)
diff --git a/sys/linux/init.go b/sys/linux/init.go
index 1f9dcc2a7..24d978381 100644
--- a/sys/linux/init.go
+++ b/sys/linux/init.go
@@ -340,14 +340,10 @@ func (arch *arch) generateTimespec(g *prog.Gen, typ0 prog.Type, dir prog.Dir, ol
 		})
 		var tpaddr prog.Arg
 		tpaddr, calls = g.Alloc(ptrArgType, prog.DirIn, tp)
-		gettime := &prog.Call{
-			Meta: meta,
-			Args: []prog.Arg{
-				prog.MakeConstArg(meta.Args[0].Type, prog.DirIn, arch.CLOCK_REALTIME),
-				tpaddr,
-			},
-			Ret: prog.MakeReturnArg(meta.Ret),
-		}
+		gettime := prog.MakeCall(meta, []prog.Arg{
+			prog.MakeConstArg(meta.Args[0].Type, prog.DirIn, arch.CLOCK_REALTIME),
+			tpaddr,
+		})
 		calls = append(calls, gettime)
 		sec := prog.MakeResultArg(typ.Fields[0].Type, dir, tp.Inner[0].(*prog.ResultArg), 0)
 		nsec := prog.MakeResultArg(typ.Fields[1].Type, dir, tp.Inner[1].(*prog.ResultArg), 0)
diff --git a/sys/targets/common.go b/sys/targets/common.go
index 193e9dca6..f55493256 100644
--- a/sys/targets/common.go
+++ b/sys/targets/common.go
@@ -21,25 +21,21 @@ func MakePosixMmap(target *prog.Target, exec, contain bool) func() []*prog.Call
 	size := target.NumPages * target.PageSize
 	const invalidFD = ^uint64(0)
 	makeMmap := func(addr, size, prot uint64) *prog.Call {
-		args := []prog.Arg{
+		call := prog.MakeCall(meta, []prog.Arg{
 			prog.MakeVmaPointerArg(meta.Args[0].Type, prog.DirIn, addr, size),
 			prog.MakeConstArg(meta.Args[1].Type, prog.DirIn, size),
 			prog.MakeConstArg(meta.Args[2].Type, prog.DirIn, prot),
 			prog.MakeConstArg(meta.Args[3].Type, prog.DirIn, flags),
 			prog.MakeResultArg(meta.Args[4].Type, prog.DirIn, nil, invalidFD),
-		}
-		i := len(args)
+		})
+		i := len(call.Args)
 		// Some targets have a padding argument between fd and offset.
 		if len(meta.Args) > 6 {
-			args = append(args, prog.MakeConstArg(meta.Args[i].Type, prog.DirIn, 0))
+			call.Args = append(call.Args, prog.MakeConstArg(meta.Args[i].Type, prog.DirIn, 0))
 			i++
 		}
-		args = append(args, prog.MakeConstArg(meta.Args[i].Type, prog.DirIn, 0))
-		return &prog.Call{
-			Meta: meta,
-			Args: args,
-			Ret:  prog.MakeReturnArg(meta.Ret),
-		}
+		call.Args = append(call.Args, prog.MakeConstArg(meta.Args[i].Type, prog.DirIn, 0))
+		return call
 	}
 	return func() []*prog.Call {
 		if contain {
@@ -58,14 +54,10 @@ func MakeSyzMmap(target *prog.Target) func() []*prog.Call {
 	size := target.NumPages * target.PageSize
 	return func() []*prog.Call {
 		return []*prog.Call{
-			{
-				Meta: meta,
-				Args: []prog.Arg{
-					prog.MakeVmaPointerArg(meta.Args[0].Type, prog.DirIn, 0, size),
-					prog.MakeConstArg(meta.Args[1].Type, prog.DirIn, size),
-				},
-				Ret: prog.MakeReturnArg(meta.Ret),
-			},
+			prog.MakeCall(meta, []prog.Arg{
+				prog.MakeVmaPointerArg(meta.Args[0].Type, prog.DirIn, 0, size),
+				prog.MakeConstArg(meta.Args[1].Type, prog.DirIn, size),
+			}),
 		}
 	}
 }
diff --git a/sys/windows/init.go b/sys/windows/init.go
index ef8ba4324..0480a6946 100644
--- a/sys/windows/init.go
+++ b/sys/windows/init.go
@@ -32,15 +32,11 @@ func (arch *arch) makeMmap() []*prog.Call {
 	meta := arch.virtualAllocSyscall
 	size := arch.target.NumPages * arch.target.PageSize
 	return []*prog.Call{
-		{
-			Meta: meta,
-			Args: []prog.Arg{
-				prog.MakeVmaPointerArg(meta.Args[0].Type, prog.DirIn, 0, size),
-				prog.MakeConstArg(meta.Args[1].Type, prog.DirIn, size),
-				prog.MakeConstArg(meta.Args[2].Type, prog.DirIn, arch.MEM_COMMIT|arch.MEM_RESERVE),
-				prog.MakeConstArg(meta.Args[3].Type, prog.DirIn, arch.PAGE_EXECUTE_READWRITE),
-			},
-			Ret: prog.MakeReturnArg(meta.Ret),
-		},
+		prog.MakeCall(meta, []prog.Arg{
+			prog.MakeVmaPointerArg(meta.Args[0].Type, prog.DirIn, 0, size),
+			prog.MakeConstArg(meta.Args[1].Type, prog.DirIn, size),
+			prog.MakeConstArg(meta.Args[2].Type, prog.DirIn, arch.MEM_COMMIT|arch.MEM_RESERVE),
+			prog.MakeConstArg(meta.Args[3].Type, prog.DirIn, arch.PAGE_EXECUTE_READWRITE),
+		}),
 	}
 }
diff --git a/tools/syz-trace2syz/proggen/proggen.go b/tools/syz-trace2syz/proggen/proggen.go
index 866dfbba0..553274728 100644
--- a/tools/syz-trace2syz/proggen/proggen.go
+++ b/tools/syz-trace2syz/proggen/proggen.go
@@ -102,14 +102,13 @@ func genProg(trace *parser.Trace, target *prog.Target) *prog.Prog {
 func (ctx *context) genCall() *prog.Call {
 	log.Logf(3, "parsing call: %s", ctx.currentStraceCall.CallName)
 	straceCall := ctx.currentStraceCall
-	ctx.currentSyzCall = new(prog.Call)
-	ctx.currentSyzCall.Meta = ctx.Select(straceCall)
-	syzCall := ctx.currentSyzCall
-	if ctx.currentSyzCall.Meta == nil {
+	meta := ctx.Select(straceCall)
+	if meta == nil {
 		log.Logf(2, "skipping call: %s which has no matching description", ctx.currentStraceCall.CallName)
 		return nil
 	}
-	syzCall.Ret = prog.MakeReturnArg(syzCall.Meta.Ret)
+	ctx.currentSyzCall = prog.MakeCall(meta, nil)
+	syzCall := ctx.currentSyzCall
 
 	for i := range syzCall.Meta.Args {
 		var strArg parser.IrType