text: /*
   * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
   * Copyright 2007, 2008, 2010, 2015 Red Hat, Inc.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   *
   */
  
  #include "precompiled.hpp"
  #include "asm/assembler.inline.hpp"
  #include "interpreter/interpreter.hpp"
  #include "nativeInst_zero.hpp"
  #include "oops/instanceOop.hpp"
  #include "oops/method.hpp"
  #include "oops/objArrayKlass.hpp"
  #include "oops/oop.inline.hpp"
  #include "prims/methodHandles.hpp"
  #include "runtime/frame.inline.hpp"
  #include "runtime/handles.inline.hpp"
  #include "runtime/sharedRuntime.hpp"
  #include "runtime/stubCodeGenerator.hpp"
  #include "runtime/stubRoutines.hpp"
  #include "runtime/thread.inline.hpp"
  #include "stack_zero.inline.hpp"
  #ifdef COMPILER2
  #include "opto/runtime.hpp"
  #endif
  
  // For SafeFetch we need POSIX tls and setjmp
  #include <setjmp.h>
  #include <pthread.h>
  static pthread_key_t g_jmpbuf_key;
  
  // return the currently active jump buffer for this thread
  //  - if there is any, NULL otherwise. Called from
  //    zero signal handlers.
  extern sigjmp_buf* get_jmp_buf_for_continuation() {
    return (sigjmp_buf*) pthread_getspecific(g_jmpbuf_key);
  }
  
  // Declaration and definition of StubGenerator (no .hpp file).
  // For a more detailed description of the stub routine structure
  // see the comment in stubRoutines.hpp
  
  class StubGenerator: public StubCodeGenerator {
   private:
    // The call stub is used to call Java from C
    static void call_stub(
      JavaCallWrapper *call_wrapper,
      intptr_t*        result,
      BasicType        result_type,
      Method*          method,
      address          entry_point,
      intptr_t*        parameters,
      int              parameter_words,
      TRAPS) {
      JavaThread *thread = THREAD;
      ZeroStack *stack = thread->zero_stack();
  
      // Make sure we have no pending exceptions
      assert(!HAS_PENDING_EXCEPTION, "call_stub called with pending exception");
  
      // Set up the stack if necessary
      bool stack_needs_teardown = false;
      if (stack->needs_setup()) {
        size_t zero_stack_size = stack->suggest_size(thread);
        stack->setup(alloca(zero_stack_size), zero_stack_size);
        stack_needs_teardown = true;
      }
  
      // Allocate and initialize our frame
      EntryFrame *frame =
        EntryFrame::build(parameters, parameter_words, call_wrapper, THREAD);
  
      if (!HAS_PENDING_EXCEPTION) {
        // Push the frame
        thread->push_zero_frame(frame);
  
        // Make the call
        Interpreter::invoke_method(method, entry_point, THREAD);
  
        // Store the result
        if (!HAS_PENDING_EXCEPTION) {
          switch (result_type) {
          case T_INT:
            *(jint *) result = *(jint *) stack->sp();
            break;
          case T_LONG:
            *(jlong *) result = *(jlong *) stack->sp();
            break;
          case T_FLOAT:
            *(jfloat *) result = *(jfloat *) stack->sp();
            break;
          case T_DOUBLE:
            *(jdouble *) result = *(jdouble *) stack->sp();
            break;
          case T_OBJECT:
            *(oop *) result = *(oop *) stack->sp();
            break;
          default:
            ShouldNotReachHere();
          }
        }
  
        // Unwind the frame
        thread->pop_zero_frame();
      }
  
      // Tear down the stack if necessary
      if (stack_needs_teardown)
        stack->teardown();
    }
  
    // These stubs get called from some dumb test routine.
    // I'll write them properly when they're called from
    // something that's actually doing something.
    static void fake_arraycopy_stub(address src, address dst, int count) {
      assert(count == 0, "huh?");
    }
  
    void generate_arraycopy_stubs() {
      // Call the conjoint generation methods immediately after
      // the disjoint ones so that short branches from the former
      // to the latter can be generated.
      StubRoutines::_jbyte_disjoint_arraycopy  = (address) fake_arraycopy_stub;
      StubRoutines::_jbyte_arraycopy           = (address) fake_arraycopy_stub;
  
      StubRoutines::_jshort_disjoint_arraycopy = (address) fake_arraycopy_stub;
      StubRoutines::_jshort_arraycopy          = (address) fake_arraycopy_stub;
  
      StubRoutines::_jint_disjoint_arraycopy   = (address) fake_arraycopy_stub;
      StubRoutines::_jint_arraycopy            = (address) fake_arraycopy_stub;
  
      StubRoutines::_jlong_disjoint_arraycopy  = (address) fake_arraycopy_stub;
      StubRoutines::_jlong_arraycopy           = (address) fake_arraycopy_stub;
  
      StubRoutines::_oop_disjoint_arraycopy    = ShouldNotCallThisStub();
      StubRoutines::_oop_arraycopy             = ShouldNotCallThisStub();
  
      StubRoutines::_checkcast_arraycopy       = ShouldNotCallThisStub();
      StubRoutines::_generic_arraycopy         = ShouldNotCallThisStub();
  
      // Shared code tests for "NULL" to discover the stub is not generated.
      StubRoutines::_unsafe_arraycopy          = NULL;
  
      // We don't generate specialized code for HeapWord-aligned source
      // arrays, so just use the code we've already generated
      StubRoutines::_arrayof_jbyte_disjoint_arraycopy =
        StubRoutines::_jbyte_disjoint_arraycopy;
      StubRoutines::_arrayof_jbyte_arraycopy =
        StubRoutines::_jbyte_arraycopy;
  
      StubRoutines::_arrayof_jshort_disjoint_arraycopy =
        StubRoutines::_jshort_disjoint_arraycopy;
      StubRoutines::_arrayof_jshort_arraycopy =
        StubRoutines::_jshort_arraycopy;
  
      StubRoutines::_arrayof_jint_disjoint_arraycopy =
        StubRoutines::_jint_disjoint_arraycopy;
      StubRoutines::_arrayof_jint_arraycopy =
        StubRoutines::_jint_arraycopy;
  
      StubRoutines::_arrayof_jlong_disjoint_arraycopy =
        StubRoutines::_jlong_disjoint_arraycopy;
      StubRoutines::_arrayof_jlong_arraycopy =
        StubRoutines::_jlong_arraycopy;
  
      StubRoutines::_arrayof_oop_disjoint_arraycopy =
        StubRoutines::_oop_disjoint_arraycopy;
      StubRoutines::_arrayof_oop_arraycopy =
        StubRoutines::_oop_arraycopy;
    }
  
    static int SafeFetch32(int *adr, int errValue) {
  
      // set up a jump buffer; anchor the pointer to the jump buffer in tls; then
      // do the pointer access. If pointer is invalid, we crash; in signal
      // handler, we retrieve pointer to jmp buffer from tls, and jump back.
      //
      // Note: the jump buffer itself - which can get pretty large depending on
      // the architecture - lives on the stack and that is fine, because we will
      // not rewind the stack: either we crash, in which case signal handler
      // frame is below us, or we don't crash, in which case it does not matter.
      sigjmp_buf jb;
      if (sigsetjmp(jb, 1)) {
        // we crashed. clean up tls and return default value.
        pthread_setspecific(g_jmpbuf_key, NULL);
        return errValue;
      } else {
        // preparation phase
        pthread_setspecific(g_jmpbuf_key, &jb);
      }
  
      int value = errValue;
      value = *adr;
  
      // all went well. clean tls.
      pthread_setspecific(g_jmpbuf_key, NULL);
  
      return value;
    }
  
    static intptr_t SafeFetchN(intptr_t *adr, intptr_t errValue) {
  
      sigjmp_buf jb;
      if (sigsetjmp(jb, 1)) {
        // we crashed. clean up tls and return default value.
        pthread_setspecific(g_jmpbuf_key, NULL);
        return errValue;
      } else {
        // preparation phase
        pthread_setspecific(g_jmpbuf_key, &jb);
      }
  
      intptr_t value = errValue;
      value = *adr;
  
      // all went well. clean tls.
      pthread_setspecific(g_jmpbuf_key, NULL);
  
      return value;
  
    }
  
    void generate_initial() {
      // Generates all stubs and initializes the entry points
  
      // entry points that exist in all platforms Note: This is code
      // that could be shared among different platforms - however the
      // benefit seems to be smaller than the disadvantage of having a
      // much more complicated generator structure. See also comment in
      // stubRoutines.hpp.
  
      StubRoutines::_forward_exception_entry   = ShouldNotCallThisStub();
      StubRoutines::_call_stub_entry           = (address) call_stub;
      StubRoutines::_catch_exception_entry     = ShouldNotCallThisStub();
  
      // atomic calls
      StubRoutines::_atomic_xchg_entry         = ShouldNotCallThisStub();
      StubRoutines::_atomic_xchg_long_entry    = ShouldNotCallThisStub();
      StubRoutines::_atomic_cmpxchg_entry      = ShouldNotCallThisStub();
      StubRoutines::_atomic_cmpxchg_byte_entry = ShouldNotCallThisStub();
      StubRoutines::_atomic_cmpxchg_long_entry = ShouldNotCallThisStub();
      StubRoutines::_atomic_add_entry          = ShouldNotCallThisStub();
      StubRoutines::_atomic_add_long_entry     = ShouldNotCallThisStub();
      StubRoutines::_fence_entry               = ShouldNotCallThisStub();
    }
  
    void generate_all() {
      // Generates all stubs and initializes the entry points
  
      // These entry points require SharedInfo::stack0 to be set up in
      // non-core builds and need to be relocatable, so they each
      // fabricate a RuntimeStub internally.
      StubRoutines::_throw_AbstractMethodError_entry =
        ShouldNotCallThisStub();
  
      StubRoutines::_throw_NullPointerException_at_call_entry =
        ShouldNotCallThisStub();
  
      StubRoutines::_throw_StackOverflowError_entry =
        ShouldNotCallThisStub();
  
      // support for verify_oop (must happen after universe_init)
      StubRoutines::_verify_oop_subroutine_entry =
        ShouldNotCallThisStub();
  
      // arraycopy stubs used by compilers
      generate_arraycopy_stubs();
  
      // Safefetch stubs.
      pthread_key_create(&g_jmpbuf_key, NULL);
      StubRoutines::_safefetch32_entry = CAST_FROM_FN_PTR(address, StubGenerator::SafeFetch32);
      StubRoutines::_safefetch32_fault_pc = NULL;
      StubRoutines::_safefetch32_continuation_pc = NULL;
  
      StubRoutines::_safefetchN_entry = CAST_FROM_FN_PTR(address, StubGenerator::SafeFetchN);
      StubRoutines::_safefetchN_fault_pc = NULL;
      StubRoutines::_safefetchN_continuation_pc = NULL;
    }
  
   public:
    StubGenerator(CodeBuffer* code, bool all) : StubCodeGenerator(code) {
      if (all) {
        generate_all();
      } else {
        generate_initial();
      }
    }
  };
  
  void StubGenerator_generate(CodeBuffer* code, bool all) {
    StubGenerator g(code, all);
  }
  
  EntryFrame *EntryFrame::build(const intptr_t*  parameters,
                                int              parameter_words,
                                JavaCallWrapper* call_wrapper,
                                TRAPS) {
  
    ZeroStack *stack = THREAD->zero_stack();
    stack->overflow_check(header_words + parameter_words, CHECK_NULL);
  
    stack->push(0); // next_frame, filled in later
    intptr_t *fp = stack->sp();
    assert(fp - stack->sp() == next_frame_off, "should be");
  
    stack->push(ENTRY_FRAME);
    assert(fp - stack->sp() == frame_type_off, "should be");
  
    stack->push((intptr_t) call_wrapper);
    assert(fp - stack->sp() == call_wrapper_off, "should be");
  
    for (int i = 0; i < parameter_words; i++)
      stack->push(parameters[i]);
  
    return (EntryFrame *) fp;
  }
  