Simplify handling of exits from with and catch.

src/arm/macro-assembler-arm.cc

 // Copyright 2011 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 1084 matching lines @@
   mov(r1, Operand(ExternalReference(Runtime::kDebugBreak, isolate())));
   CEntryStub ces(1);
   Call(ces.GetCode(), RelocInfo::DEBUG_BREAK);
 }
 #endif
 
 
 void MacroAssembler::PushTryHandler(CodeLocation try_location,
                                     HandlerType type) {
   // Adjust this code if not the case.
-  ASSERT(StackHandlerConstants::kSize == 4 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kSize == 5 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kStateOffset == 1 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kContextOffset == 2 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kFPOffset == 3 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kPCOffset == 4 * kPointerSize);
+
   // The pc (return address) is passed in register lr.
   if (try_location == IN_JAVASCRIPT) {
     if (type == TRY_CATCH_HANDLER) {
       mov(r3, Operand(StackHandler::TRY_CATCH));
     } else {
       mov(r3, Operand(StackHandler::TRY_FINALLY));
     }
-    ASSERT(StackHandlerConstants::kStateOffset == 1 * kPointerSize
-           && StackHandlerConstants::kFPOffset == 2 * kPointerSize
-           && StackHandlerConstants::kPCOffset == 3 * kPointerSize);
-    stm(db_w, sp, r3.bit() | fp.bit() | lr.bit());
+    stm(db_w, sp, r3.bit() | cp.bit() | fp.bit() | lr.bit());
     // Save the current handler as the next handler.
     mov(r3, Operand(ExternalReference(Isolate::k_handler_address, isolate())));
     ldr(r1, MemOperand(r3));
-    ASSERT(StackHandlerConstants::kNextOffset == 0);
     push(r1);
     // Link this handler as the new current one.
     str(sp, MemOperand(r3));
   } else {
     // Must preserve r0-r4, r5-r7 are available.
     ASSERT(try_location == IN_JS_ENTRY);
     // The frame pointer does not point to a JS frame so we save NULL
     // for fp. We expect the code throwing an exception to check fp
     // before dereferencing it to restore the context.
-    mov(ip, Operand(0, RelocInfo::NONE));  // To save a NULL frame pointer.
-    mov(r6, Operand(StackHandler::ENTRY));
-    ASSERT(StackHandlerConstants::kStateOffset == 1 * kPointerSize
-           && StackHandlerConstants::kFPOffset == 2 * kPointerSize
-           && StackHandlerConstants::kPCOffset == 3 * kPointerSize);
-    stm(db_w, sp, r6.bit() | ip.bit() | lr.bit());
+    mov(r5, Operand(StackHandler::ENTRY));  // State.
+    mov(r6, Operand(Smi::FromInt(0)));  // Indicates no context.
+    mov(r7, Operand(0, RelocInfo::NONE));  // NULL frame pointer.
+    stm(db_w, sp, r5.bit() | r6.bit() | r7.bit() | lr.bit());
     // Save the current handler as the next handler.
     mov(r7, Operand(ExternalReference(Isolate::k_handler_address, isolate())));
     ldr(r6, MemOperand(r7));
-    ASSERT(StackHandlerConstants::kNextOffset == 0);
     push(r6);
     // Link this handler as the new current one.
     str(sp, MemOperand(r7));
   }
 }
 
 
 void MacroAssembler::PopTryHandler() {
-  ASSERT_EQ(0, StackHandlerConstants::kNextOffset);
+  STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0);
   pop(r1);
   mov(ip, Operand(ExternalReference(Isolate::k_handler_address, isolate())));
   add(sp, sp, Operand(StackHandlerConstants::kSize - kPointerSize));
   str(r1, MemOperand(ip));
 }
 
 
 void MacroAssembler::Throw(Register value) {
+  // Adjust this code if not the case.
+  STATIC_ASSERT(StackHandlerConstants::kSize == 5 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kStateOffset == 1 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kContextOffset == 2 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kFPOffset == 3 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kPCOffset == 4 * kPointerSize);
   // r0 is expected to hold the exception.
   if (!value.is(r0)) {
     mov(r0, value);
   }
 
-  // Adjust this code if not the case.
-  STATIC_ASSERT(StackHandlerConstants::kSize == 4 * kPointerSize);
-
   // Drop the sp to the top of the handler.
   mov(r3, Operand(ExternalReference(Isolate::k_handler_address, isolate())));
   ldr(sp, MemOperand(r3));
 
-  // Restore the next handler and frame pointer, discard handler state.
-  STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0);
+  // Restore the next handler.
   pop(r2);
   str(r2, MemOperand(r3));
-  STATIC_ASSERT(StackHandlerConstants::kFPOffset == 2 * kPointerSize);
-  ldm(ia_w, sp, r3.bit() | fp.bit());  // r3: discarded 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.
-  cmp(fp, Operand(0, RelocInfo::NONE));
-  // Set cp to NULL if fp is NULL.
-  mov(cp, Operand(0, RelocInfo::NONE), LeaveCC, eq);
-  // Restore cp otherwise.
-  ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset), ne);
+  // Restore context and frame pointer, discard state (r3).
+  ldm(ia_w, sp, r3.bit() | cp.bit() | fp.bit());
+
+  // If the handler is a JS frame, restore the context to the frame.
+  // (r3 == ENTRY) == (fp == 0) == (cp == 0), so we could test any
+  // of them.
+  cmp(r3, Operand(StackHandler::ENTRY));
+  str(cp, MemOperand(fp, StandardFrameConstants::kContextOffset), ne);
+
 #ifdef DEBUG
   if (emit_debug_code()) {
     mov(lr, Operand(pc));
   }
 #endif
-  STATIC_ASSERT(StackHandlerConstants::kPCOffset == 3 * kPointerSize);
   pop(pc);
 }
 
 
 void MacroAssembler::ThrowUncatchable(UncatchableExceptionType type,
                                       Register value) {
   // Adjust this code if not the case.
-  STATIC_ASSERT(StackHandlerConstants::kSize == 4 * kPointerSize);
-
+  STATIC_ASSERT(StackHandlerConstants::kSize == 5 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kStateOffset == 1 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kContextOffset == 2 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kFPOffset == 3 * kPointerSize);
+  STATIC_ASSERT(StackHandlerConstants::kPCOffset == 4 * kPointerSize);
   // r0 is expected to hold the exception.
   if (!value.is(r0)) {
     mov(r0, value);
   }
 
   // Drop sp to the top stack handler.
   mov(r3, Operand(ExternalReference(Isolate::k_handler_address, isolate())));
   ldr(sp, MemOperand(r3));
 
   // 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::kStateOffset;
   ldr(r2, MemOperand(sp, kStateOffset));
   cmp(r2, Operand(StackHandler::ENTRY));
   b(eq, &done);
   // Fetch the next handler in the list.
   const int kNextOffset = StackHandlerConstants::kNextOffset;
   ldr(sp, MemOperand(sp, kNextOffset));
   jmp(&loop);
   bind(&done);
 
   // Set the top handler address to next handler past the current ENTRY handler.
-  STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0);
   pop(r2);
   str(r2, MemOperand(r3));
 
   if (type == OUT_OF_MEMORY) {
     // Set external caught exception to false.
     ExternalReference external_caught(
         Isolate::k_external_caught_exception_address, isolate());
     mov(r0, Operand(false, RelocInfo::NONE));
     mov(r2, Operand(external_caught));
     str(r0, MemOperand(r2));
 
     // Set pending exception and r0 to out of memory exception.
     Failure* out_of_memory = Failure::OutOfMemoryException();
     mov(r0, Operand(reinterpret_cast<int32_t>(out_of_memory)));
     mov(r2, Operand(ExternalReference(Isolate::k_pending_exception_address,
                                       isolate())));
     str(r0, MemOperand(r2));
   }
 
   // Stack layout at this point. See also StackHandlerConstants.
   // sp ->   state (ENTRY)
+  //         cp
   //         fp
   //         lr
 
-  // Discard handler state (r2 is not used) and restore frame pointer.
-  STATIC_ASSERT(StackHandlerConstants::kFPOffset == 2 * kPointerSize);
-  ldm(ia_w, sp, r2.bit() | fp.bit());  // r2: discarded 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.
-  cmp(fp, Operand(0, RelocInfo::NONE));
-  // Set cp to NULL if fp is NULL.
-  mov(cp, Operand(0, RelocInfo::NONE), LeaveCC, eq);
-  // Restore cp otherwise.
-  ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset), ne);
+  // Restore context and frame pointer, discard state (r2).
+  ldm(ia_w, sp, r2.bit() | cp.bit() | fp.bit());
 #ifdef DEBUG
   if (emit_debug_code()) {
     mov(lr, Operand(pc));
   }
 #endif
-  STATIC_ASSERT(StackHandlerConstants::kPCOffset == 3 * kPointerSize);
   pop(pc);
 }
 
 
 void MacroAssembler::CheckAccessGlobalProxy(Register holder_reg,
                                             Register scratch,
                                             Label* miss) {
   Label same_contexts;
 
   ASSERT(!holder_reg.is(scratch));
@@ skipping 1960 matching lines @@
 void CodePatcher::EmitCondition(Condition cond) {
   Instr instr = Assembler::instr_at(masm_.pc_);
   instr = (instr & ~kCondMask) | cond;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM