pkg/ast, pkg/compiler: support per-file metadata

We have a bunch of hacks in syz-extract, syz-sysgen and syz-check
with respect to description files unsupported on some arches,
or that must not be part of make extract.

Add 2 meta attribtues to files:

meta noextract
Tells `make extract` to not extract constants for this file.
Though, `syz-extract` can still be invoked manually on this file.

meta arches["arch1", "arch2"]
Restricts this file only to the given set of architectures.
`make extract` and ``make generate` will not use it on other architectures.

Later we can potentially use meta attributes to specify git tree/commit
that must be used for extraction. Maybe something else.

Fixes #2754

1 files changed, 20 insertions, 0 deletions

diff --git a/pkg/compiler/compiler.go b/pkg/compiler/compiler.go
index 62a102d40..b3e39be06 100644
--- a/pkg/compiler/compiler.go
+++ b/pkg/compiler/compiler.go
@@ -7,6 +7,7 @@ package compiler
 
 import (
 	"fmt"
+	"path/filepath"
 	"sort"
 	"strconv"
 	"strings"
@@ -74,6 +75,7 @@ func createCompiler(desc *ast.Description, target *targets.Target, eh ast.ErrorH
 // Compile compiles sys description.
 func Compile(desc *ast.Description, consts map[string]uint64, target *targets.Target, eh ast.ErrorHandler) *Prog {
 	comp := createCompiler(desc.Clone(), target, eh)
+	comp.filterArch()
 	comp.typecheck()
 	// The subsequent, more complex, checks expect basic validity of the tree,
 	// in particular corrent number of type arguments. If there were errors,
@@ -151,6 +153,24 @@ func (comp *compiler) warning(pos ast.Pos, msg string, args ...interface{}) {
 	comp.warnings = append(comp.warnings, warn{pos, fmt.Sprintf(msg, args...)})
 }
 
+func (comp *compiler) filterArch() {
+	files := comp.fileList()
+	comp.desc = comp.desc.Filter(func(n ast.Node) bool {
+		pos, typ, name := n.Info()
+		meta := files[filepath.Base(pos.File)]
+		if meta.SupportsArch(comp.target.Arch) {
+			return true
+		}
+		switch n.(type) {
+		case *ast.Resource, *ast.Struct, *ast.Call, *ast.TypeDef:
+			// This is required to keep the unsupported diagnostic working,
+			// otherwise sysgen will think that these things are still supported on some arches.
+			comp.unsupported[typ+" "+name] = true
+		}
+		return false
+	})
+}
+
 func (comp *compiler) structIsVarlen(name string) bool {
 	if varlen, ok := comp.structVarlen[name]; ok {
 		return varlen