[interpreter] Fix and test for printing of bytecodes.

test/unittests/interpreter/bytecodes-unittest.cc

Index: test/unittests/interpreter/bytecodes-unittest.cc
diff --git a/test/unittests/interpreter/bytecodes-unittest.cc b/test/unittests/interpreter/bytecodes-unittest.cc
index 5472927a40630ac98b34345d3da890903c821298..f45781718a343624aa38be4e6fb10e5a2e1a98d4 100644
--- a/test/unittests/interpreter/bytecodes-unittest.cc
+++ b/test/unittests/interpreter/bytecodes-unittest.cc
@@ -177,6 +177,65 @@ TEST(Bytecodes, DebugBreakExistForEachBytecode) {
 #undef CHECK_DEBUG_BREAK_SIZE
 }
 
+TEST(Bytecodes, DecodeBytecodeAndOperands) {
+  struct BytecodesAndResult {
+    const uint8_t bytecode[32];
+    const size_t length;
+    int parameter_count;
+    const char* output;
+  };
+
+#define B(Name) static_cast<uint8_t>(Bytecode::k##Name)
+  const BytecodesAndResult cases[] = {
+      {{B(LdaSmi), 0x01}, 2, 0, "            LdaSmi [1]"},
+      {{B(Wide), B(LdaSmi), 0xe8, 0x03}, 4, 0, "      LdaSmi.Wide [1000]"},
+      {{B(ExtraWide), B(LdaSmi), 0xa0, 0x86, 0x01, 0x00},
+       6,
+       0,
+       "LdaSmi.ExtraWide [100000]"},
+      {{B(LdaSmi), 0xff}, 2, 0, "            LdaSmi [-1]"},
+      {{B(Wide), B(LdaSmi), 0x18, 0xfc}, 4, 0, "      LdaSmi.Wide [-1000]"},
+      {{B(ExtraWide), B(LdaSmi), 0x60, 0x79, 0xfe, 0xff},
+       6,
+       0,
+       "LdaSmi.ExtraWide [-100000]"},
+      {{B(Star), 0xfb}, 2, 0, "            Star r5"},
+      {{B(Wide), B(Star), 0x78, 0xff}, 4, 0, "      Star.Wide r136"},
+      {{B(Wide), B(Call), 0x7a, 0xff, 0x79, 0xff, 0x02, 0x00, 0xb1, 0x00},
+       10,
+       0,
+       "Call.Wide r134, r135, #2, [177]"},
+      {{B(Ldar),
+        static_cast<uint8_t>(Register::FromParameterIndex(2, 3).ToOperand())},
+       2,
+       3,
+       "            Ldar a1"},
+  };
+#undef B
+
+  for (size_t i = 0; i < arraysize(cases); ++i) {
+    // Generate reference string by prepending formatted bytes.
+    std::stringstream expected_ss;
+    std::ios ios_fmt(nullptr);

[rmcilroy, 2016/03/22 17:15:37]

nit - default_format  ?

[oth, 2016/03/23 10:10:06]

Done.

+    ios_fmt.copyfmt(expected_ss);
+    expected_ss.fill('0');

[rmcilroy, 2016/03/22 17:15:37]

nit - newline, and a comment to explain what this is doing (setting formatting
used to write out the prepending raw bytes of the bytecode).

+    expected_ss.flags(std::ios::right | std::ios::hex);
+    for (size_t b = 0; b < cases[i].length; b++) {
+      expected_ss << std::setw(2) << static_cast<uint32_t>(cases[i].bytecode[b])
+                << ' ';
+    }
+    expected_ss.copyfmt(ios_fmt);
+    expected_ss << cases[i].output;
+
+    // Generate decoded byte output.
+    std::stringstream actual_ss;
+    Bytecodes::Decode(actual_ss, cases[i].bytecode, cases[i].parameter_count);
+
+    // Compare.
+    CHECK_EQ(actual_ss.str(), expected_ss.str());
+  }
+}
+
 TEST(Bytecodes, DebugBreakForPrefixBytecodes) {
   CHECK_EQ(Bytecode::kDebugBreakWide,
            Bytecodes::GetDebugBreak(Bytecode::kWide));