Rework the way we handle the fact that the ARM simulator uses a

separate JS stack.

In exception handling, we need to be able to compare addresses into
the JavaScript portion of the stack with the address of a C++ handler
on the stack.  Since the stacks are separate on the simulator, we need
a JavaScript stack address corresponding to a C++ try catch handler in
order to perform valid address comparisons.

On the simulator, we now link the C++ try catch handlers indirectly
through the JS stack and use the JS stack indirection address for
comparisons.

      JS                    C++
                           
                           handler
 [C++ address]   <------    next_
                \
                 \
                  \---->   handler
 [C++ address]   <------    next_


On actual hardware the C++ try catch handlers continue to be directly
linked.

BUG=http://code.google.com/p/v8/issues/detail?id=271
Review URL: http://codereview.chromium.org/360004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3228 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

include/v8.h

@@ -129,8 +129,9 @@ class Data;
 
 namespace internal {
 
-class Object;
 class Arguments;
+class Object;
+class Top;
 
 }
 
@@ -2532,15 +2533,16 @@ class V8EXPORT TryCatch {
    */
   void SetCaptureMessage(bool value);
 
- public:
-  TryCatch* next_;
+ private:
+  void* next_;
   void* exception_;
   void* message_;
   bool is_verbose_ : 1;
   bool can_continue_ : 1;
   bool capture_message_ : 1;
   bool rethrow_ : 1;
-  void* js_handler_;
+
+  friend class v8::internal::Top;
 };
 
 

src/api.cc

@@ -1191,14 +1191,13 @@ void Script::SetData(v8::Handle<Value> data) {
 
 
 v8::TryCatch::TryCatch()
-    : next_(i::Top::try_catch_handler()),
+    : next_(i::Top::try_catch_handler_address()),
       exception_(i::Heap::the_hole_value()),
       message_(i::Smi::FromInt(0)),
       is_verbose_(false),
       can_continue_(true),
       capture_message_(true),
-      rethrow_(false),
-      js_handler_(NULL) {
+      rethrow_(false) {
   i::Top::RegisterTryCatchHandler(this);
 }
 

src/arm/simulator-arm.cc

@@ -1924,6 +1924,25 @@ int32_t Simulator::Call(byte* entry, int argument_count, ...) {
   return result;
 }
 
+
+uintptr_t Simulator::PushAddress(uintptr_t address) {
+  int new_sp = get_register(sp) - sizeof(uintptr_t);
+  uintptr_t* stack_slot = reinterpret_cast<uintptr_t*>(new_sp);
+  *stack_slot = address;
+  set_register(sp, new_sp);
+  return new_sp;
+}
+
+
+uintptr_t Simulator::PopAddress() {
+  int current_sp = get_register(sp);
+  uintptr_t* stack_slot = reinterpret_cast<uintptr_t*>(current_sp);
+  uintptr_t address = *stack_slot;
+  set_register(sp, current_sp + sizeof(uintptr_t));
+  return address;
+}
+
+
 } }  // namespace assembler::arm
 
 #endif  // !defined(__arm__)

src/arm/simulator-arm.h

@@ -52,6 +52,12 @@ class SimulatorStack : public v8::internal::AllStatic {
   static inline uintptr_t JsLimitFromCLimit(uintptr_t c_limit) {
     return c_limit;
   }
+
+  static inline uintptr_t RegisterCTryCatch(uintptr_t try_catch_address) {
+    return try_catch_address;
+  }
+
+  static inline void UnregisterCTryCatch() { }
 };
 
 
@@ -60,6 +66,10 @@ class SimulatorStack : public v8::internal::AllStatic {
 #define CALL_GENERATED_REGEXP_CODE(entry, p0, p1, p2, p3, p4, p5, p6) \
   entry(p0, p1, p2, p3, p4, p5, p6)
 
+#define TRY_CATCH_FROM_ADDRESS(try_catch_address) \
+  reinterpret_cast<TryCatch*>(try_catch_address)
+
+
 #else  // defined(__arm__)
 
 // When running with the simulator transition into simulated execution at this
@@ -73,6 +83,11 @@ class SimulatorStack : public v8::internal::AllStatic {
   assembler::arm::Simulator::current()->Call( \
     FUNCTION_ADDR(entry), 7, p0, p1, p2, p3, p4, p5, p6)
 
+#define TRY_CATCH_FROM_ADDRESS(try_catch_address) \
+  try_catch_address == NULL ? \
+      NULL : *(reinterpret_cast<TryCatch**>(try_catch_address))
+
+
 #include "constants-arm.h"
 
 
@@ -124,6 +139,12 @@ class Simulator {
   // which sets up the simulator state and grabs the result on return.
   int32_t Call(byte* entry, int argument_count, ...);
 
+  // Push an address onto the JS stack.
+  uintptr_t PushAddress(uintptr_t address);
+
+  // Pop an address from the JS stack.
+  uintptr_t PopAddress();
+
  private:
   enum special_values {
     // Known bad pc value to ensure that the simulator does not execute
@@ -198,20 +219,20 @@ class Simulator {
   void SetFpResult(const double& result);
   void TrashCallerSaveRegisters();
 
-  // architecture state
+  // Architecture state.
   int32_t registers_[16];
   bool n_flag_;
   bool z_flag_;
   bool c_flag_;
   bool v_flag_;
 
-  // simulator support
+  // Simulator support.
   char* stack_;
   bool pc_modified_;
   int icount_;
   static bool initialized_;
 
-  // registered breakpoints
+  // Registered breakpoints.
   Instr* break_pc_;
   instr_t break_instr_;
 };
@@ -229,6 +250,15 @@ class SimulatorStack : public v8::internal::AllStatic {
   static inline uintptr_t JsLimitFromCLimit(uintptr_t c_limit) {
     return assembler::arm::Simulator::current()->StackLimit();
   }
+
+  static inline uintptr_t RegisterCTryCatch(uintptr_t try_catch_address) {
+    assembler::arm::Simulator* sim = assembler::arm::Simulator::current();
+    return sim->PushAddress(try_catch_address);
+  }
+
+  static inline void UnregisterCTryCatch() {
+    assembler::arm::Simulator::current()->PopAddress();
+  }
 };
 
 

src/execution.cc

@@ -31,18 +31,8 @@
 
 #include "api.h"
 #include "codegen-inl.h"
-
-#if V8_TARGET_ARCH_IA32
-#include "ia32/simulator-ia32.h"
-#elif V8_TARGET_ARCH_X64
-#include "x64/simulator-x64.h"
-#elif V8_TARGET_ARCH_ARM
-#include "arm/simulator-arm.h"
-#else
-#error Unsupported target architecture.
-#endif
-
 #include "debug.h"
+#include "simulator.h"
 #include "v8threads.h"
 
 namespace v8 {

src/ia32/simulator-ia32.h

@@ -43,6 +43,12 @@ class SimulatorStack : public v8::internal::AllStatic {
   static inline uintptr_t JsLimitFromCLimit(uintptr_t c_limit) {
     return c_limit;
   }
+
+  static inline uintptr_t RegisterCTryCatch(uintptr_t try_catch_address) {
+    return try_catch_address;
+  }
+
+  static inline void UnregisterCTryCatch() { }
 };
 
 // Call the generated regexp code directly. The entry function pointer should
@@ -50,4 +56,7 @@ class SimulatorStack : public v8::internal::AllStatic {
 #define CALL_GENERATED_REGEXP_CODE(entry, p0, p1, p2, p3, p4, p5, p6) \
   entry(p0, p1, p2, p3, p4, p5, p6)
 
+#define TRY_CATCH_FROM_ADDRESS(try_catch_address) \
+  reinterpret_cast<TryCatch*>(try_catch_address)
+
 #endif  // V8_IA32_SIMULATOR_IA32_H_

src/regexp-macro-assembler.cc

@@ -30,13 +30,7 @@
 #include "assembler.h"
 #include "regexp-stack.h"
 #include "regexp-macro-assembler.h"
-#if V8_TARGET_ARCH_ARM
-#include "arm/simulator-arm.h"
-#elif V8_TARGET_ARCH_IA32
-#include "ia32/simulator-ia32.h"
-#elif V8_TARGET_ARCH_X64
-#include "x64/simulator-x64.h"
-#endif
+#include "simulator.h"
 
 namespace v8 {
 namespace internal {

src/simulator.h

+// Copyright 2009 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.
+
+#ifndef V8_SIMULATOR_H_
+#define V8_SIMULATOR_H_
+
+#if V8_TARGET_ARCH_IA32
+#include "ia32/simulator-ia32.h"
+#elif V8_TARGET_ARCH_X64
+#include "x64/simulator-x64.h"
+#elif V8_TARGET_ARCH_ARM
+#include "arm/simulator-arm.h"
+#else
+#error Unsupported target architecture.
+#endif
+
+#endif  // V8_SIMULATOR_H_

src/top.cc

@@ -31,8 +31,9 @@
 #include "bootstrapper.h"
 #include "debug.h"
 #include "execution.h"
-#include "string-stream.h"
 #include "platform.h"
+#include "simulator.h"
+#include "string-stream.h"
 
 namespace v8 {
 namespace internal {
@@ -50,6 +51,30 @@ Address top_addresses[] = {
     NULL
 };
 
+
+v8::TryCatch* ThreadLocalTop::TryCatchHandler() {
+  return TRY_CATCH_FROM_ADDRESS(try_catch_handler_address());
+}
+
+
+void ThreadLocalTop::Initialize() {
+  c_entry_fp_ = 0;
+  handler_ = 0;
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  js_entry_sp_ = 0;
+#endif
+  stack_is_cooked_ = false;
+  try_catch_handler_address_ = NULL;
+  context_ = NULL;
+  int id = ThreadManager::CurrentId();
+  thread_id_ = (id == 0) ? ThreadManager::kInvalidId : id;
+  external_caught_exception_ = false;
+  failed_access_check_callback_ = NULL;
+  save_context_ = NULL;
+  catcher_ = NULL;
+}
+
+
 Address Top::get_address_from_id(Top::AddressId id) {
   return top_addresses[id];
 }
@@ -70,9 +95,9 @@ void Top::Iterate(ObjectVisitor* v, ThreadLocalTop* thread) {
   v->VisitPointer(bit_cast<Object**, Context**>(&(thread->context_)));
   v->VisitPointer(&(thread->scheduled_exception_));
 
-  for (v8::TryCatch* block = thread->try_catch_handler_;
+  for (v8::TryCatch* block = thread->TryCatchHandler();
        block != NULL;
-       block = block->next_) {
+       block = TRY_CATCH_FROM_ADDRESS(block->next_)) {
     v->VisitPointer(bit_cast<Object**, void**>(&(block->exception_)));
     v->VisitPointer(bit_cast<Object**, void**>(&(block->message_)));
   }
@@ -91,23 +116,10 @@ void Top::Iterate(ObjectVisitor* v) {
 
 
 void Top::InitializeThreadLocal() {
-  thread_local_.c_entry_fp_ = 0;
-  thread_local_.handler_ = 0;
-#ifdef ENABLE_LOGGING_AND_PROFILING
-  thread_local_.js_entry_sp_ = 0;
-#endif
-  thread_local_.stack_is_cooked_ = false;
-  thread_local_.try_catch_handler_ = NULL;
-  thread_local_.context_ = NULL;
-  int id = ThreadManager::CurrentId();
-  thread_local_.thread_id_ = (id == 0) ? ThreadManager::kInvalidId : id;
-  thread_local_.external_caught_exception_ = false;
-  thread_local_.failed_access_check_callback_ = NULL;
+  thread_local_.Initialize();
   clear_pending_exception();
   clear_pending_message();
   clear_scheduled_exception();
-  thread_local_.save_context_ = NULL;
-  thread_local_.catcher_ = NULL;
 }
 
 
@@ -254,46 +266,24 @@ void Top::TearDown() {
 }
 
 
-// There are cases where the C stack is separated from JS stack (ARM simulator).
-// To figure out the order of top-most JS try-catch handler and the top-most C
-// try-catch handler, the C try-catch handler keeps a reference to the top-most
-// JS try_catch handler when it was created.
-//
-// Here is a picture to explain the idea:
-//   Top::thread_local_.handler_       Top::thread_local_.try_catch_handler_
-//
-//             |                                         |
-//             v                                         v
-//
-//      | JS handler  |                        | C try_catch handler |
-//      |    next     |--+           +-------- |    js_handler_      |
-//                       |           |         |      next_          |--+
-//                       |           |                                  |
-//      | JS handler  |--+ <---------+                                  |
-//      |    next     |
-//
-// If the top-most JS try-catch handler is not equal to
-// Top::thread_local_.try_catch_handler_.js_handler_, it means the JS handler
-// is on the top. Otherwise, it means the C try-catch handler is on the top.
-//
 void Top::RegisterTryCatchHandler(v8::TryCatch* that) {
-  StackHandler* handler =
-    reinterpret_cast<StackHandler*>(thread_local_.handler_);
-
-  // Find the top-most try-catch handler.
-  while (handler != NULL && !handler->is_try_catch()) {
-    handler = handler->next();
-  }
-
-  that->js_handler_ = handler;  // casted to void*
-  thread_local_.try_catch_handler_ = that;
+  // The ARM simulator has a separate JS stack.  We therefore register
+  // the C++ try catch handler with the simulator and get back an
+  // address that can be used for comparisons with addresses into the
+  // JS stack.  When running without the simulator, the address
+  // returned will be the address of the C++ try catch handler itself.
+  Address address = reinterpret_cast<Address>(
+      SimulatorStack::RegisterCTryCatch(reinterpret_cast<uintptr_t>(that)));
+  thread_local_.set_try_catch_handler_address(address);
 }
 
 
 void Top::UnregisterTryCatchHandler(v8::TryCatch* that) {
-  ASSERT(thread_local_.try_catch_handler_ == that);
-  thread_local_.try_catch_handler_ = that->next_;
+  ASSERT(thread_local_.TryCatchHandler() == that);
+  thread_local_.set_try_catch_handler_address(
+      reinterpret_cast<Address>(that->next_));
   thread_local_.catcher_ = NULL;
+  SimulatorStack::UnregisterCTryCatch();
 }
 
 
@@ -725,20 +715,18 @@ bool Top::ShouldReturnException(bool* is_caught_externally,
 
   // Get the address of the external handler so we can compare the address to
   // determine which one is closer to the top of the stack.
-  v8::TryCatch* try_catch = thread_local_.try_catch_handler_;
+  Address external_handler_address = thread_local_.try_catch_handler_address();
 
   // The exception has been externally caught if and only if there is
   // an external handler which is on top of the top-most try-catch
   // handler.
-  //
-  // See comments in RegisterTryCatchHandler for details.
-  *is_caught_externally = try_catch != NULL &&
-      (handler == NULL || handler == try_catch->js_handler_ ||
+  *is_caught_externally = external_handler_address != NULL &&
+      (handler == NULL || handler->address() > external_handler_address ||
        !catchable_by_javascript);
 
   if (*is_caught_externally) {
     // Only report the exception if the external handler is verbose.
-    return thread_local_.try_catch_handler_->is_verbose_;
+    return thread_local_.TryCatchHandler()->is_verbose_;
   } else {
     // Report the exception if it isn't caught by JavaScript code.
     return handler == NULL;
@@ -775,7 +763,7 @@ void Top::DoThrow(Object* exception,
   MessageLocation potential_computed_location;
   bool try_catch_needs_message =
       is_caught_externally &&
-      thread_local_.try_catch_handler_->capture_message_;
+      thread_local_.TryCatchHandler()->capture_message_;
   if (report_exception || try_catch_needs_message) {
     if (location == NULL) {
       // If no location was specified we use a computed one instead
@@ -806,7 +794,7 @@ void Top::DoThrow(Object* exception,
   }
 
   if (is_caught_externally) {
-    thread_local_.catcher_ = thread_local_.try_catch_handler_;
+    thread_local_.catcher_ = thread_local_.TryCatchHandler();
   }
 
   // NOTE: Notifying the debugger or generating the message
@@ -830,15 +818,15 @@ void Top::ReportPendingMessages() {
   } else if (thread_local_.pending_exception_ ==
              Heap::termination_exception()) {
     if (external_caught) {
-      thread_local_.try_catch_handler_->can_continue_ = false;
-      thread_local_.try_catch_handler_->exception_ = Heap::null_value();
+      thread_local_.TryCatchHandler()->can_continue_ = false;
+      thread_local_.TryCatchHandler()->exception_ = Heap::null_value();
     }
   } else {
     Handle<Object> exception(pending_exception());
     thread_local_.external_caught_exception_ = false;
     if (external_caught) {
-      thread_local_.try_catch_handler_->can_continue_ = true;
-      thread_local_.try_catch_handler_->exception_ =
+      thread_local_.TryCatchHandler()->can_continue_ = true;
+      thread_local_.TryCatchHandler()->exception_ =
         thread_local_.pending_exception_;
       if (!thread_local_.pending_message_obj_->IsTheHole()) {
         try_catch_handler()->message_ = thread_local_.pending_message_obj_;
@@ -892,9 +880,9 @@ bool Top::OptionalRescheduleException(bool is_bottom_call) {
       // If the exception is externally caught, clear it if there are no
       // JavaScript frames on the way to the C++ frame that has the
       // external handler.
-      ASSERT(thread_local_.try_catch_handler_ != NULL);
+      ASSERT(thread_local_.try_catch_handler_address() != NULL);
       Address external_handler_address =
-          reinterpret_cast<Address>(thread_local_.try_catch_handler_);
+          thread_local_.try_catch_handler_address();
       JavaScriptFrameIterator it;
       if (it.done() || (it.frame()->sp() > external_handler_address)) {
         clear_exception = true;

src/top.h

@@ -43,6 +43,41 @@ class SaveContext;  // Forward declaration.
 
 class ThreadLocalTop BASE_EMBEDDED {
  public:
+  // Initialize the thread data.
+  void Initialize();
+
+  // Get the top C++ try catch handler or NULL if none are registered.
+  //
+  // This method is not guarenteed to return an address that can be
+  // used for comparison with addresses into the JS stack.  If such an
+  // address is needed, use try_catch_handler_address.
+  v8::TryCatch* TryCatchHandler();
+
+  // Get the address of the top C++ try catch handler or NULL if
+  // none are registered.
+  //
+  // This method always returns an address that can be compared to
+  // pointers into the JavaScript stack.  When running on actual
+  // hardware, try_catch_handler_address and TryCatchHandler return
+  // the same pointer.  When running on a simulator with a separate JS
+  // stack, try_catch_handler_address returns a JS stack address that
+  // corresponds to the place on the JS stack where the C++ handler
+  // would have been if the stack were not separate.
+  inline Address try_catch_handler_address() {
+    return try_catch_handler_address_;
+  }
+
+  // Set the address of the top C++ try catch handler.
+  inline void set_try_catch_handler_address(Address address) {
+    try_catch_handler_address_ = address;
+  }
+
+  void Free() {
+    ASSERT(!has_pending_message_);
+    ASSERT(!external_caught_exception_);
+    ASSERT(try_catch_handler_address_ == NULL);
+  }
+
   // The context where the current execution method is created and for variable
   // lookups.
   Context* context_;
@@ -59,7 +94,6 @@ class ThreadLocalTop BASE_EMBEDDED {
   // unify them later.
   Object* scheduled_exception_;
   bool external_caught_exception_;
-  v8::TryCatch* try_catch_handler_;
   SaveContext* save_context_;
   v8::TryCatch* catcher_;
 
@@ -79,11 +113,8 @@ class ThreadLocalTop BASE_EMBEDDED {
   // Call back function to report unsafe JS accesses.
   v8::FailedAccessCheckCallback failed_access_check_callback_;
 
-  void Free() {
-    ASSERT(!has_pending_message_);
-    ASSERT(!external_caught_exception_);
-    ASSERT(try_catch_handler_ == NULL);
-  }
+ private:
+  Address try_catch_handler_address_;
 };
 
 #define TOP_ADDRESS_LIST(C)            \
@@ -157,7 +188,10 @@ class Top {
     thread_local_.pending_message_script_ = NULL;
   }
   static v8::TryCatch* try_catch_handler() {
-    return thread_local_.try_catch_handler_;
+    return thread_local_.TryCatchHandler();
+  }
+  static Address try_catch_handler_address() {
+    return thread_local_.try_catch_handler_address();
   }
   // This method is called by the api after operations that may throw
   // exceptions.  If an exception was thrown and not handled by an external
@@ -189,7 +223,7 @@ class Top {
     thread_local_.external_caught_exception_ =
         has_pending_exception() &&
         (thread_local_.catcher_ != NULL) &&
-        (thread_local_.try_catch_handler_ == thread_local_.catcher_);
+        (try_catch_handler() == thread_local_.catcher_);
   }
 
   // Tells whether the current context has experienced an out of memory

src/v8.cc

@@ -30,13 +30,10 @@
 #include "bootstrapper.h"
 #include "debug.h"
 #include "serialize.h"
+#include "simulator.h"
 #include "stub-cache.h"
 #include "oprofile-agent.h"
 
-#if V8_TARGET_ARCH_ARM
-#include "arm/simulator-arm.h"
-#endif
-
 namespace v8 {
 namespace internal {
 

src/x64/simulator-x64.h

@@ -44,6 +44,12 @@ class SimulatorStack : public v8::internal::AllStatic {
   static inline uintptr_t JsLimitFromCLimit(uintptr_t c_limit) {
     return c_limit;
   }
+
+  static inline uintptr_t RegisterCTryCatch(uintptr_t try_catch_address) {
+    return try_catch_address;
+  }
+
+  static inline void UnregisterCTryCatch() { }
 };
 
 // Call the generated regexp code directly. The entry function pointer should
@@ -51,4 +57,7 @@ class SimulatorStack : public v8::internal::AllStatic {
 #define CALL_GENERATED_REGEXP_CODE(entry, p0, p1, p2, p3, p4, p5, p6) \
   entry(p0, p1, p2, p3, p4, p5, p6)
 
+#define TRY_CATCH_FROM_ADDRESS(try_catch_address) \
+  reinterpret_cast<TryCatch*>(try_catch_address)
+
 #endif  // V8_X64_SIMULATOR_X64_H_

test/cctest/cctest.status

@@ -65,11 +65,3 @@ test-api/OutOfMemoryNested: SKIP
 
 # BUG(355): Test crashes on ARM.
 test-log/ProfLazyMode: SKIP
-
-[ $simulator == arm ]
-
-# BUG(271): During exception propagation, we compare pointers into the
-# stack.  These tests fail on the ARM simulator because the C++ and
-# the JavaScript stacks are separate.
-test-api/ExceptionOrder: FAIL
-test-api/TryCatchInTryFinally: FAIL