[deoptimizer] Fix Deoptimizer::GetDeoptInfo for last entry.

This fixes the corner-case where the method in question failed to lookup
the very last deoptimization bailout without subsequent entries within
the relocation info. Also enable a test covering this.

R=tebbi@chromium.org
TEST=cctest/test-cpu-profiler/CollectDeoptEvents

Review-Url: https://codereview.chromium.org/2565733002
Cr-Commit-Position: refs/heads/master@{#41623}

src/deoptimizer.cc

@@ -2714,6 +2714,7 @@ DeoptimizedFrameInfo::DeoptimizedFrameInfo(TranslatedState* state,
 
 
 Deoptimizer::DeoptInfo Deoptimizer::GetDeoptInfo(Code* code, Address pc) {
+  CHECK(code->instruction_start() <= pc && pc <= code->instruction_end());
   SourcePosition last_position = SourcePosition::Unknown();
   DeoptimizeReason last_reason = DeoptimizeReason::kNoReason;
   int last_deopt_id = kNoDeoptimizationId;
@@ -2723,9 +2724,7 @@ Deoptimizer::DeoptInfo Deoptimizer::GetDeoptInfo(Code* code, Address pc) {
              RelocInfo::ModeMask(RelocInfo::DEOPT_INLINING_ID);
   for (RelocIterator it(code, mask); !it.done(); it.next()) {
     RelocInfo* info = it.rinfo();
-    if (info->pc() >= pc) {
-      return DeoptInfo(last_position, last_reason, last_deopt_id);
-    }
+    if (info->pc() >= pc) break;
     if (info->rmode() == RelocInfo::DEOPT_SCRIPT_OFFSET) {
       int script_offset = static_cast<int>(info->data());
       it.next();
@@ -2738,7 +2737,7 @@ Deoptimizer::DeoptInfo Deoptimizer::GetDeoptInfo(Code* code, Address pc) {
       last_reason = static_cast<DeoptimizeReason>(info->data());
     }
   }
-  return DeoptInfo(SourcePosition::Unknown(), DeoptimizeReason::kNoReason, -1);
+  return DeoptInfo(last_position, last_reason, last_deopt_id);
 }
 
 

test/cctest/cctest.status

@@ -332,9 +332,6 @@
 
 ##############################################################################
 ['variant == turbofan or variant == ignition_turbofan', {
-  # BUG(4751). Deopts with kNotASmi instead of expected deopt reason.
-  'test-cpu-profiler/CollectDeoptEvents': [SKIP],
-
   # BUG(4751). Flaky with Ignition.
   'test-cpu-profiler/JsNativeJsSample': [SKIP],
 

test/cctest/test-cpu-profiler.cc

@@ -1872,15 +1872,20 @@ TEST(CollectDeoptEvents) {
 
   {
     const char* branch[] = {"", "opt_function0", "opt_function0"};
-    CHECK_EQ(reason(i::DeoptimizeReason::kNotAHeapNumber),
-             GetBranchDeoptReason(env, iprofile, branch, arraysize(branch)));
+    const char* deopt_reason =
+        GetBranchDeoptReason(env, iprofile, branch, arraysize(branch));
+    if (deopt_reason != reason(i::DeoptimizeReason::kNotAHeapNumber) &&
+        deopt_reason != reason(i::DeoptimizeReason::kNotASmi)) {
+      FATAL(deopt_reason);
+    }
   }
   {
     const char* branch[] = {"", "opt_function1", "opt_function1"};
     const char* deopt_reason =
         GetBranchDeoptReason(env, iprofile, branch, arraysize(branch));
     if (deopt_reason != reason(i::DeoptimizeReason::kNaN) &&
-        deopt_reason != reason(i::DeoptimizeReason::kLostPrecisionOrNaN)) {
+        deopt_reason != reason(i::DeoptimizeReason::kLostPrecisionOrNaN) &&
+        deopt_reason != reason(i::DeoptimizeReason::kNotASmi)) {
       FATAL(deopt_reason);
     }
   }