Mercurial > hg > graal-compiler
view src/share/vm/opto/optoreg.hpp @ 7172:bbc14465e7db
8003689: MemTracker::init_tracking_options() reads outside array if commandline argument is empty
Summary: Fixed potential buffer overrun when giving empty option to NativeMemoryTracking commandline option
Reviewed-by: ctornqvi, hseigel, kvn
author | zgu |
---|---|
date | Wed, 28 Nov 2012 09:19:38 -0500 |
parents | f6f3bb0ee072 |
children | a7114d3d712e |
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/* * Copyright (c) 2006, 2011, 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. * */ #ifndef SHARE_VM_OPTO_OPTOREG_HPP #define SHARE_VM_OPTO_OPTOREG_HPP //------------------------------OptoReg---------------------------------------- // We eventually need Registers for the Real World. Registers are essentially // non-SSA names. A Register is represented as a number. Non-regular values // (e.g., Control, Memory, I/O) use the Special register. The actual machine // registers (as described in the ADL file for a machine) start at zero. // Stack-slots (spill locations) start at the nest Chunk past the last machine // register. // // Note that stack spill-slots are treated as a very large register set. // They have all the correct properties for a Register: not aliased (unique // named). There is some simple mapping from a stack-slot register number // to the actual location on the stack; this mapping depends on the calling // conventions and is described in the ADL. // // Note that Name is not enum. C++ standard defines that the range of enum // is the range of smallest bit-field that can represent all enumerators // declared in the enum. The result of assigning a value to enum is undefined // if the value is outside the enumeration's valid range. OptoReg::Name is // typedef'ed as int, because it needs to be able to represent spill-slots. // class OptoReg VALUE_OBJ_CLASS_SPEC { friend class C2Compiler; public: typedef int Name; enum { // Chunk 0 Physical = AdlcVMDeps::Physical, // Start of physical regs // A few oddballs at the edge of the world Special = -2, // All special (not allocated) values Bad = -1 // Not a register }; private: static const VMReg opto2vm[REG_COUNT]; static Name vm2opto[ConcreteRegisterImpl::number_of_registers]; public: // Stack pointer register static OptoReg::Name c_frame_pointer; // Increment a register number. As in: // "for ( OptoReg::Name i; i=Control; i = add(i,1) ) ..." static Name add( Name x, int y ) { return Name(x+y); } // (We would like to have an operator+ for RegName, but it is not // a class, so this would be illegal in C++.) static void dump( int ); // Get the stack slot number of an OptoReg::Name static unsigned int reg2stack( OptoReg::Name r) { assert( r >= stack0(), " must be"); return r - stack0(); } // convert a stack slot number into an OptoReg::Name static OptoReg::Name stack2reg( int idx) { return Name(stack0() + idx); } static bool is_stack(Name n) { return n >= stack0(); } static bool is_valid(Name n) { return (n != Bad); } static bool is_reg(Name n) { return is_valid(n) && !is_stack(n); } static VMReg as_VMReg(OptoReg::Name n) { if (is_reg(n)) { // Must use table, it'd be nice if Bad was indexable... return opto2vm[n]; } else { assert(!is_stack(n), "must un warp"); return VMRegImpl::Bad(); } } // Can un-warp a stack slot or convert a register or Bad static VMReg as_VMReg(OptoReg::Name n, int frame_size, int arg_count) { if (is_reg(n)) { // Must use table, it'd be nice if Bad was indexable... return opto2vm[n]; } else if (is_stack(n)) { int stack_slot = reg2stack(n); if (stack_slot < arg_count) { return VMRegImpl::stack2reg(stack_slot + frame_size); } return VMRegImpl::stack2reg(stack_slot - arg_count); // return return VMRegImpl::stack2reg(reg2stack(OptoReg::add(n, -arg_count))); } else { return VMRegImpl::Bad(); } } static OptoReg::Name as_OptoReg(VMReg r) { if (r->is_stack()) { assert(false, "must warp"); return stack2reg(r->reg2stack()); } else if (r->is_valid()) { // Must use table, it'd be nice if Bad was indexable... return vm2opto[r->value()]; } else { return Bad; } } static OptoReg::Name stack0() { return VMRegImpl::stack0->value(); } static const char* regname(OptoReg::Name n) { return as_VMReg(n)->name(); } }; //---------------------------OptoRegPair------------------------------------------- // Pairs of 32-bit registers for the allocator. // This is a very similar class to VMRegPair. C2 only interfaces with VMRegPair // via the calling convention code which is shared between the compilers. // Since C2 uses OptoRegs for register allocation it is more efficient to use // VMRegPair internally for nodes that can contain a pair of OptoRegs rather // than use VMRegPair and continually be converting back and forth. So normally // C2 will take in a VMRegPair from the calling convention code and immediately // convert them to an OptoRegPair and stay in the OptoReg world. The only over // conversion between OptoRegs and VMRegs is for debug info and oopMaps. This // is not a high bandwidth spot and so it is not an issue. // Note that onde other consequence of staying in the OptoReg world with OptoRegPairs // is that there are "physical" OptoRegs that are not representable in the VMReg // world, notably flags. [ But by design there is "space" in the VMReg world // for such registers they just may not be concrete ]. So if we were to use VMRegPair // then the VMReg world would have to have a representation for these registers // so that a OptoReg->VMReg->OptoReg would reproduce ther original OptoReg. As it // stands if you convert a flag (condition code) to a VMReg you will get VMRegImpl::Bad // and converting that will return OptoReg::Bad losing the identity of the OptoReg. class OptoRegPair { friend class VMStructs; private: short _second; short _first; public: void set_bad ( ) { _second = OptoReg::Bad; _first = OptoReg::Bad; } void set1 ( OptoReg::Name n ) { _second = OptoReg::Bad; _first = n; } void set2 ( OptoReg::Name n ) { _second = n + 1; _first = n; } void set_pair( OptoReg::Name second, OptoReg::Name first ) { _second= second; _first= first; } void set_ptr ( OptoReg::Name ptr ) { #ifdef _LP64 _second = ptr+1; #else _second = OptoReg::Bad; #endif _first = ptr; } OptoReg::Name second() const { return _second; } OptoReg::Name first() const { return _first; } OptoRegPair(OptoReg::Name second, OptoReg::Name first) { _second = second; _first = first; } OptoRegPair(OptoReg::Name f) { _second = OptoReg::Bad; _first = f; } OptoRegPair() { _second = OptoReg::Bad; _first = OptoReg::Bad; } }; #endif // SHARE_VM_OPTO_OPTOREG_HPP