8364660: ClassVerifier::ends_in_athrow() should be removed

Reviewed-by: phh
Backport-of: 6a9bd7781ce1ddbc90712b00fd940c4ce697a1fe

Author: GoeLin

src/hotspot/share/classfile/verifier.cpp

@@ -2439,216 +2439,6 @@ void ClassVerifier::verify_field_instructions(RawBytecodeStream* bcs,
   }
 }
 
-// Look at the method's handlers.  If the bci is in the handler's try block
-// then check if the handler_pc is already on the stack.  If not, push it
-// unless the handler has already been scanned.
-void ClassVerifier::push_handlers(ExceptionTable* exhandlers,
-                                  GrowableArray<u4>* handler_list,
-                                  GrowableArray<u4>* handler_stack,
-                                  u4 bci) {
-  int exlength = exhandlers->length();
-  for(int x = 0; x < exlength; x++) {
-    if (bci >= exhandlers->start_pc(x) && bci < exhandlers->end_pc(x)) {
-      u4 exhandler_pc = exhandlers->handler_pc(x);
-      if (!handler_list->contains(exhandler_pc)) {
-        handler_stack->append_if_missing(exhandler_pc);
-        handler_list->append(exhandler_pc);
-      }
-    }
-  }
-}
-
-// Return TRUE if all code paths starting with start_bc_offset end in
-// bytecode athrow or loop.
-bool ClassVerifier::ends_in_athrow(u4 start_bc_offset) {
-  ResourceMark rm;
-  // Create bytecode stream.
-  RawBytecodeStream bcs(method());
-  u4 code_length = method()->code_size();
-  bcs.set_start(start_bc_offset);
-  u4 target;
-  // Create stack for storing bytecode start offsets for if* and *switch.
-  GrowableArray<u4>* bci_stack = new GrowableArray<u4>(30);
-  // Create stack for handlers for try blocks containing this handler.
-  GrowableArray<u4>* handler_stack = new GrowableArray<u4>(30);
-  // Create list of handlers that have been pushed onto the handler_stack
-  // so that handlers embedded inside of their own TRY blocks only get
-  // scanned once.
-  GrowableArray<u4>* handler_list = new GrowableArray<u4>(30);
-  // Create list of visited branch opcodes (goto* and if*).
-  GrowableArray<u4>* visited_branches = new GrowableArray<u4>(30);
-  ExceptionTable exhandlers(_method());
-
-  while (true) {
-    if (bcs.is_last_bytecode()) {
-      // if no more starting offsets to parse or if at the end of the
-      // method then return false.
-      if ((bci_stack->is_empty()) || ((u4)bcs.end_bci() == code_length))
-        return false;
-      // Pop a bytecode starting offset and scan from there.
-      bcs.set_start(bci_stack->pop());
-    }
-    Bytecodes::Code opcode = bcs.raw_next();
-    u4 bci = bcs.bci();
-
-    // If the bytecode is in a TRY block, push its handlers so they
-    // will get parsed.
-    push_handlers(&exhandlers, handler_list, handler_stack, bci);
-
-    switch (opcode) {
-      case Bytecodes::_if_icmpeq:
-      case Bytecodes::_if_icmpne:
-      case Bytecodes::_if_icmplt:
-      case Bytecodes::_if_icmpge:
-      case Bytecodes::_if_icmpgt:
-      case Bytecodes::_if_icmple:
-      case Bytecodes::_ifeq:
-      case Bytecodes::_ifne:
-      case Bytecodes::_iflt:
-      case Bytecodes::_ifge:
-      case Bytecodes::_ifgt:
-      case Bytecodes::_ifle:
-      case Bytecodes::_if_acmpeq:
-      case Bytecodes::_if_acmpne:
-      case Bytecodes::_ifnull:
-      case Bytecodes::_ifnonnull:
-        target = bcs.dest();
-        if (visited_branches->contains(bci)) {
-          if (bci_stack->is_empty()) {
-            if (handler_stack->is_empty()) {
-              return true;
-            } else {
-              // Parse the catch handlers for try blocks containing athrow.
-              bcs.set_start(handler_stack->pop());
-            }
-          } else {
-            // Pop a bytecode starting offset and scan from there.
-            bcs.set_start(bci_stack->pop());
-          }
-        } else {
-          if (target > bci) { // forward branch
-            if (target >= code_length) return false;
-            // Push the branch target onto the stack.
-            bci_stack->push(target);
-            // then, scan bytecodes starting with next.
-            bcs.set_start(bcs.next_bci());
-          } else { // backward branch
-            // Push bytecode offset following backward branch onto the stack.
-            bci_stack->push(bcs.next_bci());
-            // Check bytecodes starting with branch target.
-            bcs.set_start(target);
-          }
-          // Record target so we don't branch here again.
-          visited_branches->append(bci);
-        }
-        break;
-
-      case Bytecodes::_goto:
-      case Bytecodes::_goto_w: {
-        int offset = (opcode == Bytecodes::_goto ? bcs.get_offset_s2() : bcs.get_offset_s4());
-        int min_offset = -1 * max_method_code_size;
-        // Check offset for overflow
-        if (offset < min_offset || offset > max_method_code_size) return false;
-
-        target = bci + offset;
-        if (visited_branches->contains(bci)) {
-          if (bci_stack->is_empty()) {
-            if (handler_stack->is_empty()) {
-              return true;
-            } else {
-              // Parse the catch handlers for try blocks containing athrow.
-              bcs.set_start(handler_stack->pop());
-            }
-          } else {
-            // Been here before, pop new starting offset from stack.
-            bcs.set_start(bci_stack->pop());
-          }
-        } else {
-          if (target >= code_length) return false;
-          // Continue scanning from the target onward.
-          bcs.set_start(target);
-          // Record target so we don't branch here again.
-          visited_branches->append(bci);
-        }
-        break;
-        }
-
-      // Check that all switch alternatives end in 'athrow' bytecodes. Since it
-      // is  difficult to determine where each switch alternative ends, parse
-      // each switch alternative until either hit a 'return', 'athrow', or reach
-      // the end of the method's bytecodes.  This is gross but should be okay
-      // because:
-      // 1. tableswitch and lookupswitch byte codes in handlers for ctor explicit
-      //    constructor invocations should be rare.
-      // 2. if each switch alternative ends in an athrow then the parsing should be
-      //    short.  If there is no athrow then it is bogus code, anyway.
-      case Bytecodes::_lookupswitch:
-      case Bytecodes::_tableswitch:
-        {
-          address aligned_bcp = align_up(bcs.bcp() + 1, jintSize);
-          u4 default_offset = Bytes::get_Java_u4(aligned_bcp) + bci;
-          int keys, delta;
-          if (opcode == Bytecodes::_tableswitch) {
-            jint low = (jint)Bytes::get_Java_u4(aligned_bcp + jintSize);
-            jint high = (jint)Bytes::get_Java_u4(aligned_bcp + 2*jintSize);
-            // This is invalid, but let the regular bytecode verifier
-            // report this because the user will get a better error message.
-            if (low > high) return true;
-            keys = high - low + 1;
-            delta = 1;
-          } else {
-            keys = (int)Bytes::get_Java_u4(aligned_bcp + jintSize);
-            delta = 2;
-          }
-          // Invalid, let the regular bytecode verifier deal with it.
-          if (keys < 0) return true;
-
-          // Push the offset of the next bytecode onto the stack.
-          bci_stack->push(bcs.next_bci());
-
-          // Push the switch alternatives onto the stack.
-          for (int i = 0; i < keys; i++) {
-            int min_offset = -1 * max_method_code_size;
-            int offset = (jint)Bytes::get_Java_u4(aligned_bcp+(3+i*delta)*jintSize);
-            if (offset < min_offset || offset > max_method_code_size) return false;
-            u4 target = bci + offset;
-            if (target > code_length) return false;
-            bci_stack->push(target);
-          }
-
-          // Start bytecode parsing for the switch at the default alternative.
-          if (default_offset > code_length) return false;
-          bcs.set_start(default_offset);
-          break;
-        }
-
-      case Bytecodes::_return:
-        return false;
-
-      case Bytecodes::_athrow:
-        {
-          if (bci_stack->is_empty()) {
-            if (handler_stack->is_empty()) {
-              return true;
-            } else {
-              // Parse the catch handlers for try blocks containing athrow.
-              bcs.set_start(handler_stack->pop());
-            }
-          } else {
-            // Pop a bytecode offset and starting scanning from there.
-            bcs.set_start(bci_stack->pop());
-          }
-        }
-        break;
-
-      default:
-        ;
-    } // end switch
-  } // end while loop
-
-  return false;
-}
-
 void ClassVerifier::verify_invoke_init(
     RawBytecodeStream* bcs, u2 ref_class_index, VerificationType ref_class_type,
     StackMapFrame* current_frame, u4 code_length, bool in_try_block,
@@ -2673,25 +2463,6 @@ void ClassVerifier::verify_invoke_init(
     // sure that all catch clause paths end in a throw.  Otherwise, this can
     // result in returning an incomplete object.
     if (in_try_block) {
-      ExceptionTable exhandlers(_method());
-      int exlength = exhandlers.length();
-      for(int i = 0; i < exlength; i++) {
-        u2 start_pc = exhandlers.start_pc(i);
-        u2 end_pc = exhandlers.end_pc(i);
-
-        if (bci >= start_pc && bci < end_pc) {
-          if (!ends_in_athrow(exhandlers.handler_pc(i))) {
-            verify_error(ErrorContext::bad_code(bci),
-              "Bad <init> method call from after the start of a try block");
-            return;
-          } else if (log_is_enabled(Debug, verification)) {
-            ResourceMark rm(THREAD);
-            log_debug(verification)("Survived call to ends_in_athrow(): %s",
-                                          current_class()->name()->as_C_string());
-          }
-        }
-      }
-
       // Check the exception handler target stackmaps with the locals from the
       // incoming stackmap (before initialize_object() changes them to outgoing
       // state).

src/hotspot/share/classfile/verifier.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -336,17 +336,6 @@ class ClassVerifier : public StackObj {
     bool* this_uninit, const constantPoolHandle& cp, StackMapTable* stackmap_table,
     TRAPS);
 
-  // Used by ends_in_athrow() to push all handlers that contain bci onto the
-  // handler_stack, if the handler has not already been pushed on the stack.
-  void push_handlers(ExceptionTable* exhandlers,
-                     GrowableArray<u4>* handler_list,
-                     GrowableArray<u4>* handler_stack,
-                     u4 bci);
-
-  // Returns true if all paths starting with start_bc_offset end in athrow
-  // bytecode or loop.
-  bool ends_in_athrow(u4 start_bc_offset);
-
   void verify_invoke_instructions(
     RawBytecodeStream* bcs, u4 code_length, StackMapFrame* current_frame,
     bool in_try_block, bool* this_uninit, VerificationType return_type,