Change the IA32 stack handler layout so that the handler address does...

src/ia32/codegen-ia32.cc

 // Copyright 2006-2009 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
@@ skipping 3234 matching lines @@
     has_unlinks = has_unlinks || shadows[i]->is_linked();
   }
   function_return_is_shadowed_ = function_return_was_shadowed;
 
   // Get an external reference to the handler address.
   ExternalReference handler_address(Top::k_handler_address);
 
   // Make sure that there's nothing left on the stack above the
   // handler structure.
   if (FLAG_debug_code) {
+    ASSERT(StackHandlerConstants::kAddressDisplacement == 0);
     __ mov(eax, Operand::StaticVariable(handler_address));
-    __ lea(eax, Operand(eax, StackHandlerConstants::kAddressDisplacement));
     __ cmp(esp, Operand(eax));
     __ Assert(equal, "stack pointer should point to top handler");
   }
 
   // If we can fall off the end of the try block, unlink from try chain.
   if (has_valid_frame()) {
     // The next handler address is on top of the frame.  Unlink from
     // the handler list and drop the rest of this handler from the
     // frame.
+    ASSERT(StackHandlerConstants::kNextOffset == 0);
     frame_->EmitPop(Operand::StaticVariable(handler_address));
     frame_->Drop(StackHandlerConstants::kSize / kPointerSize - 1);
     if (has_unlinks) {
       exit.Jump();
     }
   }
 
   // Generate unlink code for the (formerly) shadowing targets that
   // have been jumped to.  Deallocate each shadow target.
   Result return_value;
   for (int i = 0; i < shadows.length(); i++) {
     if (shadows[i]->is_linked()) {
       // Unlink from try chain; be careful not to destroy the TOS if
       // there is one.
       if (i == kReturnShadowIndex) {
         shadows[i]->Bind(&return_value);
         return_value.ToRegister(eax);
       } else {
         shadows[i]->Bind();
       }
       // Because we can be jumping here (to spilled code) from
       // unspilled code, we need to reestablish a spilled frame at
       // this block.
       frame_->SpillAll();
 
       // Reload sp from the top handler, because some statements that we
       // break from (eg, for...in) may have left stuff on the stack.
-      __ mov(edx, Operand::StaticVariable(handler_address));
-      const int kNextOffset = StackHandlerConstants::kNextOffset +
-          StackHandlerConstants::kAddressDisplacement;
-      __ lea(esp, Operand(edx, kNextOffset));
+      ASSERT(StackHandlerConstants::kAddressDisplacement == 0);
+      __ mov(esp, Operand::StaticVariable(handler_address));
       frame_->Forget(frame_->height() - handler_height);
 
+      ASSERT(StackHandlerConstants::kNextOffset == 0);
       frame_->EmitPop(Operand::StaticVariable(handler_address));
       frame_->Drop(StackHandlerConstants::kSize / kPointerSize - 1);
-      // next_sp popped.
 
       if (i == kReturnShadowIndex) {
         if (!function_return_is_shadowed_) frame_->PrepareForReturn();
         shadows[i]->other_target()->Jump(&return_value);
       } else {
         shadows[i]->other_target()->Jump();
       }
     }
   }
 
@@ skipping 64 matching lines @@
   function_return_is_shadowed_ = function_return_was_shadowed;
 
   // Get an external reference to the handler address.
   ExternalReference handler_address(Top::k_handler_address);
 
   // If we can fall off the end of the try block, unlink from the try
   // chain and set the state on the frame to FALLING.
   if (has_valid_frame()) {
     // The next handler address is on top of the frame.
     ASSERT(StackHandlerConstants::kNextOffset == 0);
-    frame_->EmitPop(eax);
-    __ mov(Operand::StaticVariable(handler_address), eax);
+    frame_->EmitPop(Operand::StaticVariable(handler_address));
     frame_->Drop(StackHandlerConstants::kSize / kPointerSize - 1);
 
     // Fake a top of stack value (unneeded when FALLING) and set the
     // state in ecx, then jump around the unlink blocks if any.
     frame_->EmitPush(Immediate(Factory::undefined_value()));
     __ Set(ecx, Immediate(Smi::FromInt(FALLING)));
     if (nof_unlinks > 0) {
       finally_block.Jump();
     }
   }
@@ skipping 13 matching lines @@
         shadows[i]->Bind();
       }
       // Because we can be jumping here (to spilled code) from
       // unspilled code, we need to reestablish a spilled frame at
       // this block.
       frame_->SpillAll();
 
       // Reload sp from the top handler, because some statements that
       // we break from (eg, for...in) may have left stuff on the
       // stack.
-      __ mov(edx, Operand::StaticVariable(handler_address));
-      const int kNextOffset = StackHandlerConstants::kNextOffset +
-          StackHandlerConstants::kAddressDisplacement;
-      __ lea(esp, Operand(edx, kNextOffset));
+      ASSERT(StackHandlerConstants::kAddressDisplacement == 0);
+      __ mov(esp, Operand::StaticVariable(handler_address));
       frame_->Forget(frame_->height() - handler_height);
 
       // Unlink this handler and drop it from the frame.
+      ASSERT(StackHandlerConstants::kNextOffset == 0);
       frame_->EmitPop(Operand::StaticVariable(handler_address));
       frame_->Drop(StackHandlerConstants::kSize / kPointerSize - 1);
 
       if (i == kReturnShadowIndex) {
         // If this target shadowed the function return, materialize
         // the return value on the stack.
         frame_->EmitPush(eax);
       } else {
         // Fake TOS for targets that shadowed breaks and continues.
         frame_->EmitPush(Immediate(Factory::undefined_value()));
@@ skipping 3515 matching lines @@
   __ GetBuiltinEntry(edx, Builtins::CALL_NON_FUNCTION);
   Handle<Code> adaptor(Builtins::builtin(Builtins::ArgumentsAdaptorTrampoline));
   __ jmp(adaptor, RelocInfo::CODE_TARGET);
 }
 
 
 
 void CEntryStub::GenerateThrowTOS(MacroAssembler* masm) {
   // Adjust this code if not the case.
   ASSERT(StackHandlerConstants::kSize == 4 * kPointerSize);
+
+  // Drop the sp to the top of the handler.
+  ASSERT(StackHandlerConstants::kAddressDisplacement == 0);
   ExternalReference handler_address(Top::k_handler_address);
-  __ mov(edx, Operand::StaticVariable(handler_address));
-  // Get next in chain.
-  __ mov(ecx, Operand(edx, StackHandlerConstants::kAddressDisplacement));
-  __ mov(Operand::StaticVariable(handler_address), ecx);
-  __ mov(esp, Operand(edx));
+  __ mov(esp, Operand::StaticVariable(handler_address));
+
+  // Restore next handler and frame pointer, discard handler state.
+  ASSERT(StackHandlerConstants::kNextOffset == 0);
+  __ pop(Operand::StaticVariable(handler_address));
+  ASSERT(StackHandlerConstants::kFPOffset == 1 * kPointerSize);
   __ pop(ebp);
   __ pop(edx);  // Remove state.
 
   // Before returning we restore the context from the frame pointer if not NULL.
   // The frame pointer is NULL in the exception handler of a JS entry frame.
   __ xor_(esi, Operand(esi));  // tentatively set context pointer to NULL
   Label skip;
   __ cmp(ebp, 0);
   __ j(equal, &skip, not_taken);
   __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
   __ bind(&skip);
 
+  ASSERT(StackHandlerConstants::kPCOffset == 3 * kPointerSize);
   __ ret(0);
 }
 
 
 void CEntryStub::GenerateCore(MacroAssembler* masm,
                               Label* throw_normal_exception,
                               Label* throw_out_of_memory_exception,
                               StackFrame::Type frame_type,
                               bool do_gc,
                               bool always_allocate_scope) {
@@ skipping 68 matching lines @@
 
   // Retry.
   __ bind(&retry);
 }
 
 
 void CEntryStub::GenerateThrowOutOfMemory(MacroAssembler* masm) {
   // Adjust this code if not the case.
   ASSERT(StackHandlerConstants::kSize == 4 * kPointerSize);
 
-  // Fetch top stack handler.
+  // Drop sp to the top stack handler.
+  ASSERT(StackHandlerConstants::kAddressDisplacement == 0);
   ExternalReference handler_address(Top::k_handler_address);
-  __ mov(edx, Operand::StaticVariable(handler_address));
+  __ mov(esp, Operand::StaticVariable(handler_address));
 
   // Unwind the handlers until the ENTRY handler is found.
   Label loop, done;
   __ bind(&loop);
   // Load the type of the current stack handler.
-  const int kStateOffset = StackHandlerConstants::kAddressDisplacement +
-      StackHandlerConstants::kStateOffset;
-  __ cmp(Operand(edx, kStateOffset), Immediate(StackHandler::ENTRY));
+  const int kStateOffset = StackHandlerConstants::kStateOffset;
+  __ cmp(Operand(esp, kStateOffset), Immediate(StackHandler::ENTRY));
   __ j(equal, &done);
   // Fetch the next handler in the list.
-  const int kNextOffset = StackHandlerConstants::kAddressDisplacement +
-      StackHandlerConstants::kNextOffset;
-  __ mov(edx, Operand(edx, kNextOffset));
+  const int kNextOffset = StackHandlerConstants::kNextOffset;
+  __ mov(esp, Operand(esp, kNextOffset));
   __ jmp(&loop);
   __ bind(&done);
 
   // Set the top handler address to next handler past the current ENTRY handler.
-  __ mov(eax, Operand(edx, kNextOffset));
-  __ mov(Operand::StaticVariable(handler_address), eax);
+  ASSERT(StackHandlerConstants::kNextOffset == 0);
+  __ pop(Operand::StaticVariable(handler_address));
 
   // Set external caught exception to false.
+  ExternalReference external_caught(Top::k_external_caught_exception_address);
   __ mov(eax, false);
-  ExternalReference external_caught(Top::k_external_caught_exception_address);
   __ mov(Operand::StaticVariable(external_caught), eax);
 
   // Set pending exception and eax to out of memory exception.
+  ExternalReference pending_exception(Top::k_pending_exception_address);
   __ mov(eax, reinterpret_cast<int32_t>(Failure::OutOfMemoryException()));
-  ExternalReference pending_exception(Top::k_pending_exception_address);
   __ mov(Operand::StaticVariable(pending_exception), eax);
 
-  // Restore the stack to the address of the ENTRY handler
-  __ mov(esp, Operand(edx));
-
   // Clear the context pointer;
   __ xor_(esi, Operand(esi));
 
-  // Restore registers from handler.
-  __ pop(ebp);  // FP
-  __ pop(edx);  // State
+  // Restore fp from handler and discard handler state.
+  ASSERT(StackHandlerConstants::kFPOffset == 1 * kPointerSize);
+  __ pop(ebp);
+  __ pop(edx);  // State.
 
+  ASSERT(StackHandlerConstants::kPCOffset == 3 * kPointerSize);
   __ ret(0);
 }
 
 
 void CEntryStub::GenerateBody(MacroAssembler* masm, bool is_debug_break) {
   // eax: number of arguments including receiver
   // ebx: pointer to C function  (C callee-saved)
   // ebp: frame pointer  (restored after C call)
   // esp: stack pointer  (restored after C call)
   // esi: current context (C callee-saved)
@@ skipping 98 matching lines @@
   // Caught exception: Store result (exception) in the pending
   // exception field in the JSEnv and return a failure sentinel.
   ExternalReference pending_exception(Top::k_pending_exception_address);
   __ mov(Operand::StaticVariable(pending_exception), eax);
   __ mov(eax, reinterpret_cast<int32_t>(Failure::Exception()));
   __ jmp(&exit);
 
   // Invoke: Link this frame into the handler chain.
   __ bind(&invoke);
   __ PushTryHandler(IN_JS_ENTRY, JS_ENTRY_HANDLER);
-  __ push(eax);  // flush TOS
 
   // Clear any pending exceptions.
   __ mov(edx,
          Operand::StaticVariable(ExternalReference::the_hole_value_location()));
   __ mov(Operand::StaticVariable(pending_exception), edx);
 
   // Fake a receiver (NULL).
   __ push(Immediate(0));  // receiver
 
   // Invoke the function by calling through JS entry trampoline
@@ skipping 94 matching lines @@
 
   // Slow-case: Go through the JavaScript implementation.
   __ bind(&slow);
   __ InvokeBuiltin(Builtins::INSTANCE_OF, JUMP_FUNCTION);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal