Mercurial > hg > truffle
view src/share/vm/asm/assembler.cpp @ 20256:b0b97602393a
8033923: Use BufferingOopClosure for G1 code root scanning
Reviewed-by: mgerdin, brutisso
author | stefank |
---|---|
date | Mon, 10 Feb 2014 12:58:09 +0100 |
parents | 55fb97c4c58d |
children | 4ca6dc0799b6 |
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/* * Copyright (c) 1997, 2013, 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. * */ #include "precompiled.hpp" #include "asm/macroAssembler.hpp" #include "asm/macroAssembler.inline.hpp" #include "asm/codeBuffer.hpp" #include "runtime/atomic.hpp" #include "runtime/atomic.inline.hpp" #include "runtime/icache.hpp" #include "runtime/os.hpp" // Implementation of AbstractAssembler // // The AbstractAssembler is generating code into a CodeBuffer. To make code generation faster, // the assembler keeps a copy of the code buffers boundaries & modifies them when // emitting bytes rather than using the code buffers accessor functions all the time. // The code buffer is updated via set_code_end(...) after emitting a whole instruction. AbstractAssembler::AbstractAssembler(CodeBuffer* code) { if (code == NULL) return; CodeSection* cs = code->insts(); cs->clear_mark(); // new assembler kills old mark if (cs->start() == NULL) { vm_exit_out_of_memory(0, OOM_MMAP_ERROR, err_msg("CodeCache: no room for %s", code->name())); } _code_section = cs; _oop_recorder= code->oop_recorder(); DEBUG_ONLY( _short_branch_delta = 0; ) } void AbstractAssembler::set_code_section(CodeSection* cs) { assert(cs->outer() == code_section()->outer(), "sanity"); assert(cs->is_allocated(), "need to pre-allocate this section"); cs->clear_mark(); // new assembly into this section kills old mark _code_section = cs; } // Inform CodeBuffer that incoming code and relocation will be for stubs address AbstractAssembler::start_a_stub(int required_space) { CodeBuffer* cb = code(); CodeSection* cs = cb->stubs(); assert(_code_section == cb->insts(), "not in insts?"); if (cs->maybe_expand_to_ensure_remaining(required_space) && cb->blob() == NULL) { return NULL; } set_code_section(cs); return pc(); } // Inform CodeBuffer that incoming code and relocation will be code // Should not be called if start_a_stub() returned NULL void AbstractAssembler::end_a_stub() { assert(_code_section == code()->stubs(), "not in stubs?"); set_code_section(code()->insts()); } // Inform CodeBuffer that incoming code and relocation will be for stubs address AbstractAssembler::start_a_const(int required_space, int required_align) { CodeBuffer* cb = code(); CodeSection* cs = cb->consts(); assert(_code_section == cb->insts() || _code_section == cb->stubs(), "not in insts/stubs?"); address end = cs->end(); int pad = -(intptr_t)end & (required_align-1); if (cs->maybe_expand_to_ensure_remaining(pad + required_space)) { if (cb->blob() == NULL) return NULL; end = cs->end(); // refresh pointer } if (pad > 0) { while (--pad >= 0) { *end++ = 0; } cs->set_end(end); } set_code_section(cs); return end; } // Inform CodeBuffer that incoming code and relocation will be code // in section cs (insts or stubs). void AbstractAssembler::end_a_const(CodeSection* cs) { assert(_code_section == code()->consts(), "not in consts?"); set_code_section(cs); } void AbstractAssembler::flush() { ICache::invalidate_range(addr_at(0), offset()); } void AbstractAssembler::bind(Label& L) { if (L.is_bound()) { // Assembler can bind a label more than once to the same place. guarantee(L.loc() == locator(), "attempt to redefine label"); return; } L.bind_loc(locator()); L.patch_instructions((MacroAssembler*)this); } void AbstractAssembler::generate_stack_overflow_check( int frame_size_in_bytes) { if (UseStackBanging) { // Each code entry causes one stack bang n pages down the stack where n // is configurable by StackShadowPages. The setting depends on the maximum // depth of VM call stack or native before going back into java code, // since only java code can raise a stack overflow exception using the // stack banging mechanism. The VM and native code does not detect stack // overflow. // The code in JavaCalls::call() checks that there is at least n pages // available, so all entry code needs to do is bang once for the end of // this shadow zone. // The entry code may need to bang additional pages if the framesize // is greater than a page. const int page_size = os::vm_page_size(); int bang_end = StackShadowPages*page_size; // This is how far the previous frame's stack banging extended. const int bang_end_safe = bang_end; if (frame_size_in_bytes > page_size) { bang_end += frame_size_in_bytes; } int bang_offset = bang_end_safe; while (bang_offset <= bang_end) { // Need at least one stack bang at end of shadow zone. bang_stack_with_offset(bang_offset); bang_offset += page_size; } } // end (UseStackBanging) } void Label::add_patch_at(CodeBuffer* cb, int branch_loc) { assert(_loc == -1, "Label is unbound"); if (_patch_index < PatchCacheSize) { _patches[_patch_index] = branch_loc; } else { if (_patch_overflow == NULL) { _patch_overflow = cb->create_patch_overflow(); } _patch_overflow->push(branch_loc); } ++_patch_index; } void Label::patch_instructions(MacroAssembler* masm) { assert(is_bound(), "Label is bound"); CodeBuffer* cb = masm->code(); int target_sect = CodeBuffer::locator_sect(loc()); address target = cb->locator_address(loc()); while (_patch_index > 0) { --_patch_index; int branch_loc; if (_patch_index >= PatchCacheSize) { branch_loc = _patch_overflow->pop(); } else { branch_loc = _patches[_patch_index]; } int branch_sect = CodeBuffer::locator_sect(branch_loc); address branch = cb->locator_address(branch_loc); if (branch_sect == CodeBuffer::SECT_CONSTS) { // The thing to patch is a constant word. *(address*)branch = target; continue; } #ifdef ASSERT // Cross-section branches only work if the // intermediate section boundaries are frozen. if (target_sect != branch_sect) { for (int n = MIN2(target_sect, branch_sect), nlimit = (target_sect + branch_sect) - n; n < nlimit; n++) { CodeSection* cs = cb->code_section(n); assert(cs->is_frozen(), "cross-section branch needs stable offsets"); } } #endif //ASSERT // Push the target offset into the branch instruction. masm->pd_patch_instruction(branch, target); } } struct DelayedConstant { typedef void (*value_fn_t)(); BasicType type; intptr_t value; value_fn_t value_fn; // This limit of 20 is generous for initial uses. // The limit needs to be large enough to store the field offsets // into classes which do not have statically fixed layouts. // (Initial use is for method handle object offsets.) // Look for uses of "delayed_value" in the source code // and make sure this number is generous enough to handle all of them. enum { DC_LIMIT = 20 }; static DelayedConstant delayed_constants[DC_LIMIT]; static DelayedConstant* add(BasicType type, value_fn_t value_fn); bool match(BasicType t, value_fn_t cfn) { return type == t && value_fn == cfn; } static void update_all(); }; DelayedConstant DelayedConstant::delayed_constants[DC_LIMIT]; // Default C structure initialization rules have the following effect here: // = { { (BasicType)0, (intptr_t)NULL }, ... }; DelayedConstant* DelayedConstant::add(BasicType type, DelayedConstant::value_fn_t cfn) { for (int i = 0; i < DC_LIMIT; i++) { DelayedConstant* dcon = &delayed_constants[i]; if (dcon->match(type, cfn)) return dcon; if (dcon->value_fn == NULL) { // (cmpxchg not because this is multi-threaded but because I'm paranoid) if (Atomic::cmpxchg_ptr(CAST_FROM_FN_PTR(void*, cfn), &dcon->value_fn, NULL) == NULL) { dcon->type = type; return dcon; } } } // If this assert is hit (in pre-integration testing!) then re-evaluate // the comment on the definition of DC_LIMIT. guarantee(false, "too many delayed constants"); return NULL; } void DelayedConstant::update_all() { for (int i = 0; i < DC_LIMIT; i++) { DelayedConstant* dcon = &delayed_constants[i]; if (dcon->value_fn != NULL && dcon->value == 0) { typedef int (*int_fn_t)(); typedef address (*address_fn_t)(); switch (dcon->type) { case T_INT: dcon->value = (intptr_t) ((int_fn_t) dcon->value_fn)(); break; case T_ADDRESS: dcon->value = (intptr_t) ((address_fn_t)dcon->value_fn)(); break; } } } } RegisterOrConstant AbstractAssembler::delayed_value(int(*value_fn)(), Register tmp, int offset) { intptr_t val = (intptr_t) (*value_fn)(); if (val != 0) return val + offset; return delayed_value_impl(delayed_value_addr(value_fn), tmp, offset); } RegisterOrConstant AbstractAssembler::delayed_value(address(*value_fn)(), Register tmp, int offset) { intptr_t val = (intptr_t) (*value_fn)(); if (val != 0) return val + offset; return delayed_value_impl(delayed_value_addr(value_fn), tmp, offset); } intptr_t* AbstractAssembler::delayed_value_addr(int(*value_fn)()) { DelayedConstant* dcon = DelayedConstant::add(T_INT, (DelayedConstant::value_fn_t) value_fn); return &dcon->value; } intptr_t* AbstractAssembler::delayed_value_addr(address(*value_fn)()) { DelayedConstant* dcon = DelayedConstant::add(T_ADDRESS, (DelayedConstant::value_fn_t) value_fn); return &dcon->value; } void AbstractAssembler::update_delayed_values() { DelayedConstant::update_all(); } void AbstractAssembler::block_comment(const char* comment) { if (sect() == CodeBuffer::SECT_INSTS) { code_section()->outer()->block_comment(offset(), comment); } } const char* AbstractAssembler::code_string(const char* str) { if (sect() == CodeBuffer::SECT_INSTS || sect() == CodeBuffer::SECT_STUBS) { return code_section()->outer()->code_string(str); } return NULL; } bool MacroAssembler::needs_explicit_null_check(intptr_t offset) { // Exception handler checks the nmethod's implicit null checks table // only when this method returns false. #ifdef _LP64 if (UseCompressedOops && Universe::narrow_oop_base() != NULL) { assert (Universe::heap() != NULL, "java heap should be initialized"); // The first page after heap_base is unmapped and // the 'offset' is equal to [heap_base + offset] for // narrow oop implicit null checks. uintptr_t base = (uintptr_t)Universe::narrow_oop_base(); if ((uintptr_t)offset >= base) { // Normalize offset for the next check. offset = (intptr_t)(pointer_delta((void*)offset, (void*)base, 1)); } } #endif return offset < 0 || os::vm_page_size() <= offset; }