CodeGen: rewrite implementation [3/3]

sandbox/linux/seccomp-bpf/codegen_unittest.cc

Index: sandbox/linux/seccomp-bpf/codegen_unittest.cc
diff --git a/sandbox/linux/seccomp-bpf/codegen_unittest.cc b/sandbox/linux/seccomp-bpf/codegen_unittest.cc
index 73b0f88423c1039fa4dc1618d35538ca1e83c0f0..8cc61c79bdbb43927a9d7503001c4804f3420cea 100644
--- a/sandbox/linux/seccomp-bpf/codegen_unittest.cc
+++ b/sandbox/linux/seccomp-bpf/codegen_unittest.cc
@@ -113,13 +113,7 @@ class ProgramTest : public ::testing::Test {
     CodeGen::Addr res = gen_.MakeInstruction(code, k, jt, jf);
     EXPECT_NE(CodeGen::kNullAddr, res);
 
-    Hash digest;
-    if (code == BPF_JMP + BPF_JA) {
-      // TODO(mdempsky): Disallow use of JA.
-      digest = Lookup(jt);
-    } else {
-      digest = Hash(code, k, Lookup(jt), Lookup(jf));
-    }
+    Hash digest(code, k, Lookup(jt), Lookup(jf));
     auto it = addr_hashes_.insert(std::make_pair(res, digest));
     EXPECT_EQ(digest, it.first->second);
 
@@ -218,12 +212,12 @@ TEST_F(ProgramTest, Complex) {
   //    RET 42                           (insn3+)
   CodeGen::Addr insn0 = MakeInstruction(BPF_RET + BPF_K, 42);
   CodeGen::Addr insn1 = MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 42, insn0);
-  CodeGen::Addr insn2 = MakeInstruction(BPF_JMP + BPF_JA, 0, insn1);
+  CodeGen::Addr insn2 = insn1;  // Implicit JUMP
 
-  // We explicitly duplicate instructions so that MergeTails() can coalesce
-  // them later.
+  // We explicitly duplicate instructions to check that CodeGen merges them.
   CodeGen::Addr insn3 = MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 42,
                                         MakeInstruction(BPF_RET + BPF_K, 42));
+  EXPECT_EQ(insn2, insn3);
 
   CodeGen::Addr insn4 =
       MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K, 42, insn2, insn3);
@@ -322,5 +316,25 @@ TEST_F(ProgramTest, ConfusingTailsMergeable) {
   RunTest(i0);
 }
 
+TEST_F(ProgramTest, InstructionFolding) {
+  // Check that simple instructions are folded as expected.
+  CodeGen::Addr a = MakeInstruction(BPF_RET + BPF_K, 0);
+  EXPECT_EQ(a, MakeInstruction(BPF_RET + BPF_K, 0));
+  CodeGen::Addr b = MakeInstruction(BPF_RET + BPF_K, 1);
+  EXPECT_EQ(a, MakeInstruction(BPF_RET + BPF_K, 0));
+  EXPECT_EQ(b, MakeInstruction(BPF_RET + BPF_K, 1));
+  EXPECT_EQ(b, MakeInstruction(BPF_RET + BPF_K, 1));
+
+  // Check that complex sequences are folded too.
+  CodeGen::Addr c =
+      MakeInstruction(BPF_LD + BPF_W + BPF_ABS, 0,
+                      MakeInstruction(BPF_JMP + BPF_JSET + BPF_K, 0x100, a, b));
+  EXPECT_EQ(c, MakeInstruction(
+                   BPF_LD + BPF_W + BPF_ABS, 0,
+                   MakeInstruction(BPF_JMP + BPF_JSET + BPF_K, 0x100, a, b)));
+
+  RunTest(c);
+}
+
 }  // namespace

[rickyz (no longer on Chrome), 2014/11/12 23:43:50]

Can you add a test that calls MakeInstruction with jt/jf > 255?

[mdempsky, 2014/11/18 01:07:30]

Done.

 }  // namespace sandbox