Delete HAbnormalExit. It does more harm than good.

BUG=v8:2843
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/23462007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16406 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/lithium-arm.cc

@@ -1872,13 +1872,6 @@ LInstruction* LChunkBuilder::DoBoundsCheckBaseIndexInformation(
 }
 
 
-LInstruction* LChunkBuilder::DoAbnormalExit(HAbnormalExit* instr) {
-  // The control instruction marking the end of a block that completed
-  // abruptly (e.g., threw an exception).  There is nothing specific to do.
-  return NULL;
-}
-
-
 LInstruction* LChunkBuilder::DoThrow(HThrow* instr) {
   LOperand* value = UseFixed(instr->value(), r0);
   return MarkAsCall(new(zone()) LThrow(value), instr);

src/hydrogen-environment-liveness.cc

@@ -163,11 +163,7 @@ void HEnvironmentLivenessAnalysisPhase::UpdateLivenessAtInstruction(
       live->Clear();
       for (int i = 0; i < enter->return_targets()->length(); ++i) {
         int return_id = enter->return_targets()->at(i)->block_id();
-        // When an AbnormalExit is involved, it can happen that the return
-        // target block doesn't actually exist.
-        if (return_id < live_at_block_start_.length()) {
-          live->Union(*live_at_block_start_[return_id]);
-        }
+        live->Union(*live_at_block_start_[return_id]);
       }
       last_simulate_ = NULL;
       break;

src/hydrogen-instructions.h

@@ -63,7 +63,6 @@ class LChunkBuilder;
 
 
 #define HYDROGEN_CONCRETE_INSTRUCTION_LIST(V)  \
-  V(AbnormalExit)                              \
   V(AccessArgumentsAt)                         \
   V(Add)                                       \
   V(Allocate)                                  \
@@ -1443,16 +1442,6 @@ class HReturn V8_FINAL : public HTemplateControlInstruction<0, 3> {
 };
 
 
-class HAbnormalExit V8_FINAL : public HTemplateControlInstruction<0, 0> {
- public:
-  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
-    return Representation::None();
-  }
-
-  DECLARE_CONCRETE_INSTRUCTION(AbnormalExit)
-};
-
-
 class HUnaryOperation : public HTemplateInstruction<1> {
  public:
   HUnaryOperation(HValue* value, HType type = HType::Tagged())

src/hydrogen.cc

@@ -5406,8 +5406,6 @@ void HOptimizedGraphBuilder::VisitThrow(Throw* expr) {
   HThrow* instr = Add<HThrow>(value);
   instr->set_position(expr->position());
   Add<HSimulate>(expr->id());
-  current_block()->FinishExit(new(zone()) HAbnormalExit);
-  set_current_block(NULL);
 }
 
 

src/ia32/lithium-ia32.cc

@@ -1886,13 +1886,6 @@ LInstruction* LChunkBuilder::DoBoundsCheckBaseIndexInformation(
 }
 
 
-LInstruction* LChunkBuilder::DoAbnormalExit(HAbnormalExit* instr) {
-  // The control instruction marking the end of a block that completed
-  // abruptly (e.g., threw an exception).  There is nothing specific to do.
-  return NULL;
-}
-
-
 LInstruction* LChunkBuilder::DoThrow(HThrow* instr) {
   LOperand* context = UseFixed(instr->context(), esi);
   LOperand* value = UseFixed(instr->value(), eax);

src/mips/lithium-mips.cc

@@ -1791,13 +1791,6 @@ LInstruction* LChunkBuilder::DoBoundsCheckBaseIndexInformation(
 }
 
 
-LInstruction* LChunkBuilder::DoAbnormalExit(HAbnormalExit* instr) {
-  // The control instruction marking the end of a block that completed
-  // abruptly (e.g., threw an exception).  There is nothing specific to do.
-  return NULL;
-}
-
-
 LInstruction* LChunkBuilder::DoThrow(HThrow* instr) {
   LOperand* value = UseFixed(instr->value(), a0);
   return MarkAsCall(new(zone()) LThrow(value), instr);

src/x64/lithium-x64.cc

@@ -1789,13 +1789,6 @@ LInstruction* LChunkBuilder::DoBoundsCheckBaseIndexInformation(
 }
 
 
-LInstruction* LChunkBuilder::DoAbnormalExit(HAbnormalExit* instr) {
-  // The control instruction marking the end of a block that completed
-  // abruptly (e.g., threw an exception).  There is nothing specific to do.
-  return NULL;
-}
-
-
 LInstruction* LChunkBuilder::DoThrow(HThrow* instr) {
   LOperand* value = UseFixed(instr->value(), rax);
   return MarkAsCall(new(zone()) LThrow(value), instr);

test/mjsunit/regress/regress-2843.js

+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --allow-natives-syntax
+
+function bailout() { throw "bailout"; }
+var global;
+
+function foo(x, fun) {
+  var a = x + 1;
+  var b = x + 2;  // Need another Simulate to fold the first one into.
+  global = true;  // Need a side effect to deopt to.
+  fun();
+  return a;
+}
+
+assertThrows("foo(1, bailout)");
+assertThrows("foo(1, bailout)");
+%OptimizeFunctionOnNextCall(foo);
+assertThrows("foo(1, bailout)");
+assertEquals(2, foo(1, function() {}));