pkg/compiler: add automatic meta

Mark the whole file with "meta automatic" instead of marking each syscall.
This reduces size of descriptions + allows to do special things
with the whole file (e.g. we already treat auto consts specially).

4 files changed, 32 insertions, 21 deletions

diff --git a/pkg/compiler/compiler.go b/pkg/compiler/compiler.go
index fa23ce6bf..713c21b08 100644
--- a/pkg/compiler/compiler.go
+++ b/pkg/compiler/compiler.go
@@ -7,7 +7,6 @@ package compiler
 
 import (
 	"fmt"
-	"path/filepath"
 	"strconv"
 	"strings"
 
@@ -140,7 +139,7 @@ type compiler struct {
 	structTypes    map[string]prog.Type
 	structFiles    map[*ast.Struct]map[string]ast.Pos
 	builtinConsts  map[string]uint64
-	fileMeta       map[string]Meta
+	fileMetas      map[string]Meta
 	recursiveQuery map[ast.Node]bool
 }
 
@@ -159,13 +158,9 @@ func (comp *compiler) warning(pos ast.Pos, msg string, args ...interface{}) {
 }
 
 func (comp *compiler) filterArch() {
-	if comp.fileMeta == nil {
-		comp.fileMeta = comp.fileList()
-	}
 	comp.desc = comp.desc.Filter(func(n ast.Node) bool {
 		pos, typ, name := n.Info()
-		meta := comp.fileMeta[filepath.Base(pos.File)]
-		if meta.SupportsArch(comp.target.Arch) {
+		if comp.fileMeta(pos).SupportsArch(comp.target.Arch) {
 			return true
 		}
 		switch n.(type) {
diff --git a/pkg/compiler/consts.go b/pkg/compiler/consts.go
index 5e1ed9188..bcbd40e52 100644
--- a/pkg/compiler/consts.go
+++ b/pkg/compiler/consts.go
@@ -119,7 +119,7 @@ func (comp *compiler) extractConsts() map[string]*ConstInfo {
 			comp.extractTypeConsts(ctx, decl)
 		}
 	}
-	return convertConstInfo(ctx, comp.fileMeta)
+	return convertConstInfo(ctx, comp.fileMetas)
 }
 
 func foreachFieldAttrConst(n *ast.Struct, cb func(*ast.Type)) {
diff --git a/pkg/compiler/gen.go b/pkg/compiler/gen.go
index fb803875a..fb406b815 100644
--- a/pkg/compiler/gen.go
+++ b/pkg/compiler/gen.go
@@ -78,7 +78,7 @@ func (comp *compiler) collectCallArgSizes() map[string][]uint64 {
 				comp.error(arg.Pos, "%v arg %v is larger than pointer size", n.Name.Name, arg.Name.Name)
 				continue
 			}
-			argID := fmt.Sprintf("%v|%v", getCallName(n), i)
+			argID := fmt.Sprintf("%v|%v", comp.getCallName(n), i)
 			if _, ok := argPos[argID]; !ok {
 				argSizes[i] = typ.Size()
 				argPos[argID] = arg.Pos
@@ -90,16 +90,18 @@ func (comp *compiler) collectCallArgSizes() map[string][]uint64 {
 				continue
 			}
 		}
-		callArgSizes[getCallName(n)] = argSizes
+		callArgSizes[comp.getCallName(n)] = argSizes
 	}
 	return callArgSizes
 }
 
-func getCallName(n *ast.Call) string {
-	for _, attr := range n.Attrs {
-		if attr.Ident == "automatic" {
-			return n.Name.Name
-		}
+func (comp *compiler) getCallName(n *ast.Call) string {
+	// getCallName is used for checking that all variants of the same syscall have same argument sizes
+	// for matching arguments. Automatically-generated syscalls may violate that condition,
+	// so for them we use full syscall name. As the result manual and automatic variants
+	// of the same syscall are not checked against each other.
+	if comp.fileMeta(n.Pos).Automatic {
+		return n.Name.Name
 	}
 	return n.CallName
 }
@@ -109,7 +111,7 @@ func (comp *compiler) genSyscalls() []*prog.Syscall {
 	var calls []*prog.Syscall
 	for _, decl := range comp.desc.Nodes {
 		if n, ok := decl.(*ast.Call); ok && n.NR != ^uint64(0) {
-			calls = append(calls, comp.genSyscall(n, callArgSizes[getCallName(n)]))
+			calls = append(calls, comp.genSyscall(n, callArgSizes[comp.getCallName(n)]))
 		}
 	}
 	// We assign SquashableElem here rather than during pointer type generation
@@ -132,6 +134,7 @@ func (comp *compiler) genSyscall(n *ast.Call, argSizes []uint64) *prog.Syscall {
 		ret = comp.genType(n.Ret, comp.ptrSize)
 	}
 	var attrs prog.SyscallAttrs
+	attrs.Automatic = comp.fileMeta(n.Pos).Automatic
 	intAttrs, _, stringAttrs := comp.parseAttrs(callAttrs, n, n.Attrs)
 	for desc, val := range intAttrs {
 		fld := reflect.ValueOf(&attrs).Elem().FieldByName(desc.Name)
diff --git a/pkg/compiler/meta.go b/pkg/compiler/meta.go
index f0221d0b9..a47ab8f0b 100644
--- a/pkg/compiler/meta.go
+++ b/pkg/compiler/meta.go
@@ -11,11 +11,12 @@ import (
 )
 
 type Meta struct {
-	NoExtract bool
+	Automatic bool // automatically-generated descriptions
+	NoExtract bool // do not run syz-extract on the descriptions by default
 	Arches    map[string]bool
 }
 
-func (meta *Meta) SupportsArch(arch string) bool {
+func (meta Meta) SupportsArch(arch string) bool {
 	return len(meta.Arches) == 0 || meta.Arches[arch]
 }
 
@@ -27,6 +28,13 @@ func FileList(desc *ast.Description, OS string, eh ast.ErrorHandler) map[string]
 	return nil
 }
 
+func (comp *compiler) fileMeta(pos ast.Pos) Meta {
+	if comp.fileMetas == nil {
+		comp.fileMetas = comp.fileList()
+	}
+	return comp.fileMetas[filepath.Base(pos.File)]
+}
+
 func (comp *compiler) fileList() map[string]Meta {
 	files := make(map[string]Meta)
 	for _, n := range comp.desc.Nodes {
@@ -44,6 +52,8 @@ func (comp *compiler) fileList() map[string]Meta {
 				break
 			}
 			switch n.Value.Ident {
+			case metaAutomatic.Names[0]:
+				meta.Automatic = true
 			case metaNoExtract.Names[0]:
 				meta.NoExtract = true
 			case metaArches.Names[0]:
@@ -55,17 +65,20 @@ func (comp *compiler) fileList() map[string]Meta {
 		}
 		files[file] = meta
 	}
-	if comp.errors != 0 {
-		return nil
-	}
 	return files
 }
 
 var metaTypes = map[string]*typeDesc{
+	metaAutomatic.Names[0]: metaAutomatic,
 	metaNoExtract.Names[0]: metaNoExtract,
 	metaArches.Names[0]:    metaArches,
 }
 
+var metaAutomatic = &typeDesc{
+	Names:     []string{"automatic"},
+	CantBeOpt: true,
+}
+
 var metaNoExtract = &typeDesc{
 	Names:     []string{"noextract"},
 	CantBeOpt: true,