Decouple CodeGen from ErrorCode

sandbox/linux/seccomp-bpf/sandbox_bpf.cc

Index: sandbox/linux/seccomp-bpf/sandbox_bpf.cc
diff --git a/sandbox/linux/seccomp-bpf/sandbox_bpf.cc b/sandbox/linux/seccomp-bpf/sandbox_bpf.cc
index b90a9ef5da085b591279b790a455288a17df75ed..a5da20e82f00da1079c37dc99da4224e47ee3970 100644
--- a/sandbox/linux/seccomp-bpf/sandbox_bpf.cc
+++ b/sandbox/linux/seccomp-bpf/sandbox_bpf.cc
@@ -886,10 +886,14 @@ Instruction* SandboxBPF::AssembleJumpTable(CodeGen* gen,
 }
 
 Instruction* SandboxBPF::RetExpression(CodeGen* gen, const ErrorCode& err) {
-  if (err.error_type_ == ErrorCode::ET_COND) {
+  switch (err.error_type()) {
+    case ErrorCode::ET_COND:
     return CondExpression(gen, err);

[rickyz (no longer on Chrome), 2014/09/16 22:36:46]

nit: fix indent

[mdempsky, 2014/09/16 22:41:30]

Oops, done.

-  } else {
-    return gen->MakeInstruction(BPF_RET + BPF_K, err);
+    case ErrorCode::ET_SIMPLE:
+    case ErrorCode::ET_TRAP:
+      return gen->MakeInstruction(BPF_RET + BPF_K, err.err());
+    default:
+      SANDBOX_DIE("ErrorCode is not suitable for returning from a BPF program");

[jln (very slow on Chromium), 2014/09/16 22:42:29]

Will this work with all compilers? I think there are cases where this is not
considered noreturn, so you may need to return NULL here.

[mdempsky, 2014/09/16 22:47:44]

I think so.  There are other functions in this file (e.g., BPFFailure) that call
SANDBOX_DIE() and don't have any return statements.

   }
 }