/* * Copyright (c) 2008, 2022, 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 * 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. *
*/
// consider stack guards when trying to determine "safe" stack pointers // sp must be within the usable part of the stack (not in guards) if (!thread->is_in_usable_stack(sp)) { returnfalse;
}
if (!thread->is_in_stack_range_incl(unextended_sp, sp)) { returnfalse;
}
// We know sp/unextended_sp are safe. Only fp is questionable here.
// First check if frame is complete and tester is reliable // Unfortunately we can only check frame complete for runtime stubs and nmethod // other generic buffer blobs are more problematic so we just assume they are // ok. adapter blobs never have a frame complete and are never ok.
if (!_cb->is_frame_complete_at(_pc)) { if (_cb->is_compiled() || _cb->is_adapter_blob() || _cb->is_runtime_stub()) { returnfalse;
}
}
// Could just be some random pointer within the codeBlob if (!_cb->code_contains(_pc)) { returnfalse;
}
// Entry frame checks if (is_entry_frame()) { // an entry frame must have a valid fp. return fp_safe && is_entry_frame_valid(thread);
}
} else { // must be some sort of compiled/runtime frame // fp does not have to be safe (although it could be check for c1?)
sender_sp = _unextended_sp + _cb->frame_size(); // Is sender_sp safe? if (!thread->is_in_full_stack_checked((address)sender_sp)) { returnfalse;
} // With our calling conventions, the return_address should // end up being the word on the stack
sender_pc = (address) *(sender_sp - sender_sp_offset + return_addr_offset);
}
// We must always be able to find a recognizable pc
CodeBlob* sender_blob = CodeCache::find_blob(sender_pc); if (sender_pc == NULL || sender_blob == NULL) { returnfalse;
}
// If the potential sender is the interpreter then we can do some more checking if (Interpreter::contains(sender_pc)) {
// FP is always saved in a recognizable place in any code we generate. However // only if the sender is interpreted/call_stub (c1 too?) are we certain that the saved FP // is really a frame pointer.
// Could just be some random pointer within the codeBlob if (!sender_blob->code_contains(sender_pc)) { returnfalse;
}
// We should never be able to see an adapter if the current frame is something from code cache if (sender_blob->is_adapter_blob()) { returnfalse;
}
// Could be the call_stub if (StubRoutines::returns_to_call_stub(sender_pc)) {
intptr_t *saved_fp = (intptr_t*)*(sender_sp - frame::sender_sp_offset + link_offset); if (!thread->is_in_stack_range_excl((address)saved_fp, (address)sender_sp)) { returnfalse;
}
// construct the potential sender
frame sender(sender_sp, saved_fp, sender_pc);
// Validate the JavaCallWrapper an entry frame must have
address jcw = (address)sender.entry_frame_call_wrapper();
// If the frame size is 0 something (or less) is bad because every nmethod has a non-zero frame size // because the return address counts against the callee's frame.
if (sender_blob->frame_size() <= 0) {
assert(!sender_blob->is_compiled(), "should count return address at least"); returnfalse;
}
// We should never be able to see anything here except an nmethod. If something in the // code cache (current frame) is called by an entity within the code cache that entity // should not be anything but the call stub (already covered), the interpreter (already covered) // or an nmethod.
if (!sender_blob->is_compiled()) { returnfalse;
}
// Could put some more validation for the potential non-interpreted sender // frame we'd create by calling sender if I could think of any. Wait for next crash in forte...
// One idea is seeing if the sender_pc we have is one that we'd expect to call to current cb
// We've validated the potential sender that would be created returntrue;
}
// Must be native-compiled frame. Since sender will try and use fp to find // linkages it must be safe
if (!fp_safe) { returnfalse;
}
// Will the pc we fetch be non-zero (which we'll find at the oldest frame)
if ((address) this->fp()[return_addr_offset] == NULL) returnfalse;
// could try and do some more potential verification of native frame if we could think of some...
returntrue;
}
void frame::patch_pc(Thread* thread, address pc) {
assert(_cb == CodeCache::find_blob(pc), "unexpected pc");
address* pc_addr = &((address *)sp())[-sender_sp_offset+return_addr_offset]; if (TracePcPatching) {
tty->print_cr("patch_pc at address" INTPTR_FORMAT " [" INTPTR_FORMAT " -> " INTPTR_FORMAT "] ",
p2i(pc_addr), p2i(*pc_addr), p2i(pc));
}
DEBUG_ONLY(address old_pc = _pc;)
*pc_addr = pc;
_pc = pc; // must be set before call to get_deopt_original_pc
address original_pc = CompiledMethod::get_deopt_original_pc(this); if (original_pc != NULL) {
assert(original_pc == old_pc, "expected original PC to be stored before patching");
_deopt_state = is_deoptimized; // leave _pc as is
} else {
_deopt_state = not_deoptimized;
_pc = pc;
}
}
intptr_t* frame::entry_frame_argument_at(int offset) const {
assert(is_entry_frame(), "entry frame expected"); // convert offset to index to deal with tsi int index = (Interpreter::expr_offset_in_bytes(offset)/wordSize); // Entry frame's arguments are always in relation to unextended_sp() return &unextended_sp()[index];
}
// Used by template based interpreter deoptimization void frame::interpreter_frame_set_last_sp(intptr_t* sp) {
*((intptr_t**)addr_at(interpreter_frame_last_sp_offset)) = sp;
}
frame frame::sender_for_entry_frame(RegisterMap* map) const {
assert(map != NULL, "map must be set"); // Java frame called from C; skip all C frames and return top C // frame of that chunk as the sender
JavaFrameAnchor* jfa = entry_frame_call_wrapper()->anchor();
assert(!entry_frame_is_first(), "next Java fp must be non zero");
assert(jfa->last_Java_sp() > sp(), "must be above this frame on stack");
map->clear();
assert(map->include_argument_oops(), "should be set by clear"); if (jfa->last_Java_pc() != NULL) {
frame fr(jfa->last_Java_sp(), jfa->last_Java_fp(), jfa->last_Java_pc()); return fr;
}
frame fr(jfa->last_Java_sp(), jfa->last_Java_fp()); return fr;
}
//------------------------------------------------------------------------------ // frame::verify_deopt_original_pc // // Verifies the calculated original PC of a deoptimization PC for the // given unextended SP. The unextended SP might also be the saved SP // for MethodHandle call sites. #ifdef ASSERT void frame::verify_deopt_original_pc(CompiledMethod* nm, intptr_t* unextended_sp, bool is_method_handle_return) {
frame fr;
// This is ugly but it's better than to change {get,set}_original_pc // to take an SP value as argument. And it's only a debugging // method anyway.
fr._unextended_sp = unextended_sp;
address original_pc = nm->get_original_pc(&fr);
assert(nm->insts_contains_inclusive(original_pc), "original PC must be in the main code section of the compiled method (or must be immediately following it)");
assert(nm->is_method_handle_return(original_pc) == is_method_handle_return, "must be");
} #endif
//------------------------------------------------------------------------------ // frame::adjust_unextended_sp void frame::adjust_unextended_sp() { // same as on x86
// If we are returning to a compiled MethodHandle call site, the // saved_fp will in fact be a saved value of the unextended SP. The // simplest way to tell whether we are returning to such a call site // is as follows:
CompiledMethod* sender_cm = (_cb == NULL) ? NULL : _cb->as_compiled_method_or_null(); if (sender_cm != NULL) { // If the sender PC is a deoptimization point, get the original // PC. For MethodHandle call site the unextended_sp is stored in // saved_fp. if (sender_cm->is_deopt_mh_entry(_pc)) {
DEBUG_ONLY(verify_deopt_mh_original_pc(sender_cm, _fp));
_unextended_sp = _fp;
} elseif (sender_cm->is_deopt_entry(_pc)) {
DEBUG_ONLY(verify_deopt_original_pc(sender_cm, _unextended_sp));
} elseif (sender_cm->is_method_handle_return(_pc)) {
_unextended_sp = _fp;
}
}
}
//------------------------------------------------------------------------------ // frame::update_map_with_saved_link void frame::update_map_with_saved_link(RegisterMap* map, intptr_t** link_addr) { // see x86 for comments
map->set_location(FP->as_VMReg(), (address) link_addr);
}
frame frame::sender_for_interpreter_frame(RegisterMap* map) const { // SP is the raw SP from the sender after adapter or interpreter // extension.
intptr_t* sender_sp = this->sender_sp();
// This is the sp before any possible extension (adapter/locals).
intptr_t* unextended_sp = interpreter_frame_sender_sp();
bool frame::is_interpreted_frame_valid(JavaThread* thread) const {
assert(is_interpreted_frame(), "Not an interpreted frame"); // These are reasonable sanity checks if (fp() == 0 || (intptr_t(fp()) & (wordSize-1)) != 0) { returnfalse;
} if (sp() == 0 || (intptr_t(sp()) & (wordSize-1)) != 0) { returnfalse;
} if (fp() + interpreter_frame_initial_sp_offset < sp()) { returnfalse;
} // These are hacks to keep us out of trouble. // The problem with these is that they mask other problems if (fp() <= sp()) { // this attempts to deal with unsigned comparison above returnfalse;
} // do some validation of frame elements
// first the method
Method* m = *interpreter_frame_method_addr();
// validate the method we'd find in this potential sender if (!Method::is_valid_method(m)) returnfalse;
// stack frames shouldn't be much larger than max_stack elements
intptr_t* res_addr; if (method->is_native()) { // Prior to calling into the runtime to report the method_exit both of // the possible return value registers are saved. // Return value registers are pushed to the native stack
res_addr = (intptr_t*)sp(); #ifdef __ABI_HARD__ // FP result is pushed onto a stack along with integer result registers if (type == T_FLOAT || type == T_DOUBLE) {
res_addr += 2;
} #endif// __ABI_HARD__
} else {
res_addr = (intptr_t*)interpreter_frame_tos_address();
}
switch (type) { case T_OBJECT : case T_ARRAY : {
oop obj; if (method->is_native()) {
obj = cast_to_oop(at(interpreter_frame_oop_temp_offset));
} else {
obj = *(oop*)res_addr;
}
assert(Universe::is_in_heap_or_null(obj), "sanity check");
*oop_result = obj; break;
} case T_BOOLEAN : value_result->z = *(jboolean*)res_addr; break; case T_BYTE : value_result->b = *(jbyte*)res_addr; break; case T_CHAR : value_result->c = *(jchar*)res_addr; break; case T_SHORT : value_result->s = *(jshort*)res_addr; break; case T_INT : value_result->i = *(jint*)res_addr; break; case T_LONG : value_result->j = *(jlong*)res_addr; break; case T_FLOAT : value_result->f = *(jfloat*)res_addr; break; case T_DOUBLE : value_result->d = *(jdouble*)res_addr; break; case T_VOID : /* Nothing to do */ break; default : ShouldNotReachHere();
}
return type;
}
intptr_t* frame::interpreter_frame_tos_at(jint offset) const { int index = (Interpreter::expr_offset_in_bytes(offset)/wordSize); return &interpreter_frame_tos_address()[index];
}
void frame::describe_pd(FrameValues& values, int frame_no) { if (is_interpreted_frame()) {
DESCRIBE_FP_OFFSET(interpreter_frame_sender_sp);
DESCRIBE_FP_OFFSET(interpreter_frame_last_sp);
DESCRIBE_FP_OFFSET(interpreter_frame_method);
DESCRIBE_FP_OFFSET(interpreter_frame_mdp);
DESCRIBE_FP_OFFSET(interpreter_frame_cache);
DESCRIBE_FP_OFFSET(interpreter_frame_locals);
DESCRIBE_FP_OFFSET(interpreter_frame_bcp);
DESCRIBE_FP_OFFSET(interpreter_frame_initial_sp);
}
}
// This is a generic constructor which is only used by pns() in debug.cpp.
frame::frame(void* sp, void* fp, void* pc) {
init((intptr_t*)sp, (intptr_t*)sp, (intptr_t*)fp, (address)pc);
}
#endif
intptr_t *frame::initial_deoptimization_info() { // used to reset the saved FP return fp();
}
intptr_t* frame::real_fp() const { if (is_entry_frame()) { // Work-around: FP (currently) does not conform to the ABI for entry // frames (see generate_call_stub). Might be worth fixing as another CR. // Following code assumes (and asserts) this has not yet been fixed.
assert(frame::entry_frame_call_wrapper_offset == 0, "adjust this code");
intptr_t* new_fp = fp();
new_fp += 5; // saved R0,R1,R2,R4,R10 #ifndef __SOFTFP__
new_fp += 8*2; // saved D8..D15 #endif return new_fp;
} if (_cb != NULL) { // use the frame size if valid int size = _cb->frame_size(); if (size > 0) { return unextended_sp() + size;
}
} // else rely on fp()
assert(! is_compiled_frame(), "unknown compiled frame size"); return fp();
}
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