sys/syz-sysgen: fail on undefined consts

Ensure that every const mentioned in the description is defined for at
least one architecture.

We cannot do it inside pkg/compiler as it deals with only one arch at a
time. Also, we cannot do it inside syz-check as it's not supposed to be
called every time and may also include non-actionable warnings.

So let's do it inside syz-sysgen, which is invoked all the time and has
all the necessary data.

2 files changed, 32 insertions, 1 deletions

diff --git a/sys/syz-sysgen/check.go b/sys/syz-sysgen/check.go
new file mode 100644
index 000000000..aee850a9a
--- /dev/null
+++ b/sys/syz-sysgen/check.go
@@ -0,0 +1,26 @@
+// Copyright 2023 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package main
+
+import (
+	"fmt"
+
+	"github.com/google/syzkaller/pkg/ast"
+	"github.com/google/syzkaller/pkg/compiler"
+)
+
+// constsAreAllDefined() ensures that for every const there's at least one arch that defines it.
+func constsAreAllDefined(consts *compiler.ConstFile, constInfo map[string]*compiler.ConstInfo,
+	eh ast.ErrorHandler) {
+	// We cannot perform this check inside pkg/compiler because it's
+	// given a const slice for only one architecture.
+	for _, info := range constInfo {
+		for _, def := range info.Consts {
+			if consts.ExistsAny(def.Name) {
+				continue
+			}
+			eh(def.Pos, fmt.Sprintf("%s is defined for none of the arches", def.Name))
+		}
+	}
+}
diff --git a/sys/syz-sysgen/sysgen.go b/sys/syz-sysgen/sysgen.go
index 70b38fee5..2ab6cdbab 100644
--- a/sys/syz-sysgen/sysgen.go
+++ b/sys/syz-sysgen/sysgen.go
@@ -202,7 +202,12 @@ func processJob(job *Job, descriptions *ast.Description, constFile *compiler.Con
 
 	// Don't print warnings, they are printed in syz-check.
 	job.Errors = nil
-	job.OK = true
+	// But let's fail on always actionable errors.
+	if job.Target.OS != targets.Fuchsia {
+		// There are too many broken consts on Fuchsia.
+		constsAreAllDefined(constFile, job.ConstInfo, eh)
+	}
+	job.OK = len(job.Errors) == 0
 }
 
 func generate(target *targets.Target, prg *compiler.Prog, consts map[string]uint64, out io.Writer) {