/* * Copyright (c) 1997, 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_ASM_ASSEMBLER_HPP #define SHARE_VM_ASM_ASSEMBLER_HPP #include "code/oopRecorder.hpp" #include "code/relocInfo.hpp" #include "memory/allocation.hpp" #include "utilities/debug.hpp" #include "utilities/growableArray.hpp" #include "utilities/top.hpp" #ifdef TARGET_ARCH_x86 # include "register_x86.hpp" # include "vm_version_x86.hpp" #endif #ifdef TARGET_ARCH_sparc # include "register_sparc.hpp" # include "vm_version_sparc.hpp" #endif #ifdef TARGET_ARCH_zero # include "register_zero.hpp" # include "vm_version_zero.hpp" #endif #ifdef TARGET_ARCH_arm # include "register_arm.hpp" # include "vm_version_arm.hpp" #endif #ifdef TARGET_ARCH_ppc # include "register_ppc.hpp" # include "vm_version_ppc.hpp" #endif // This file contains platform-independent assembler declarations. class CodeBuffer; class MacroAssembler; class AbstractAssembler; class Label; /** * Labels represent destinations for control transfer instructions. Such * instructions can accept a Label as their target argument. A Label is * bound to the current location in the code stream by calling the * MacroAssembler's 'bind' method, which in turn calls the Label's 'bind' * method. A Label may be referenced by an instruction before it's bound * (i.e., 'forward referenced'). 'bind' stores the current code offset * in the Label object. * * If an instruction references a bound Label, the offset field(s) within * the instruction are immediately filled in based on the Label's code * offset. If an instruction references an unbound label, that * instruction is put on a list of instructions that must be patched * (i.e., 'resolved') when the Label is bound. * * 'bind' will call the platform-specific 'patch_instruction' method to * fill in the offset field(s) for each unresolved instruction (if there * are any). 'patch_instruction' lives in one of the * cpu//vm/assembler_* files. * * Instead of using a linked list of unresolved instructions, a Label has * an array of unresolved instruction code offsets. _patch_index * contains the total number of forward references. If the Label's array * overflows (i.e., _patch_index grows larger than the array size), a * GrowableArray is allocated to hold the remaining offsets. (The cache * size is 4 for now, which handles over 99.5% of the cases) * * Labels may only be used within a single CodeSection. If you need * to create references between code sections, use explicit relocations. */ class Label VALUE_OBJ_CLASS_SPEC { private: enum { PatchCacheSize = 4 }; // _loc encodes both the binding state (via its sign) // and the binding locator (via its value) of a label. // // _loc >= 0 bound label, loc() encodes the target (jump) position // _loc == -1 unbound label int _loc; // References to instructions that jump to this unresolved label. // These instructions need to be patched when the label is bound // using the platform-specific patchInstruction() method. // // To avoid having to allocate from the C-heap each time, we provide // a local cache and use the overflow only if we exceed the local cache int _patches[PatchCacheSize]; int _patch_index; GrowableArray* _patch_overflow; Label(const Label&) { ShouldNotReachHere(); } public: /** * After binding, be sure 'patch_instructions' is called later to link */ void bind_loc(int loc) { assert(loc >= 0, "illegal locator"); assert(_loc == -1, "already bound"); _loc = loc; } void bind_loc(int pos, int sect); // = bind_loc(locator(pos, sect)) #ifndef PRODUCT // Iterates over all unresolved instructions for printing void print_instructions(MacroAssembler* masm) const; #endif // PRODUCT /** * Returns the position of the the Label in the code buffer * The position is a 'locator', which encodes both offset and section. */ int loc() const { assert(_loc >= 0, "unbound label"); return _loc; } int loc_pos() const; // == locator_pos(loc()) int loc_sect() const; // == locator_sect(loc()) bool is_bound() const { return _loc >= 0; } bool is_unbound() const { return _loc == -1 && _patch_index > 0; } bool is_unused() const { return _loc == -1 && _patch_index == 0; } /** * Adds a reference to an unresolved displacement instruction to * this unbound label * * @param cb the code buffer being patched * @param branch_loc the locator of the branch instruction in the code buffer */ void add_patch_at(CodeBuffer* cb, int branch_loc); /** * Iterate over the list of patches, resolving the instructions * Call patch_instruction on each 'branch_loc' value */ void patch_instructions(MacroAssembler* masm); void init() { _loc = -1; _patch_index = 0; _patch_overflow = NULL; } Label() { init(); } }; // A union type for code which has to assemble both constant and // non-constant operands, when the distinction cannot be made // statically. class RegisterOrConstant VALUE_OBJ_CLASS_SPEC { private: Register _r; intptr_t _c; public: RegisterOrConstant(): _r(noreg), _c(0) {} RegisterOrConstant(Register r): _r(r), _c(0) {} RegisterOrConstant(intptr_t c): _r(noreg), _c(c) {} Register as_register() const { assert(is_register(),""); return _r; } intptr_t as_constant() const { assert(is_constant(),""); return _c; } Register register_or_noreg() const { return _r; } intptr_t constant_or_zero() const { return _c; } bool is_register() const { return _r != noreg; } bool is_constant() const { return _r == noreg; } }; // The Abstract Assembler: Pure assembler doing NO optimizations on the // instruction level; i.e., what you write is what you get. // The Assembler is generating code into a CodeBuffer. class AbstractAssembler : public ResourceObj { friend class Label; protected: CodeSection* _code_section; // section within the code buffer address _code_begin; // first byte of code buffer address _code_limit; // first byte after code buffer address _code_pos; // current code generation position OopRecorder* _oop_recorder; // support for relocInfo::oop_type // Code emission & accessing address addr_at(int pos) const { return _code_begin + pos; } // This routine is called with a label is used for an address. // Labels and displacements truck in offsets, but target must return a PC. address target(Label& L); // return _code_section->target(L) bool is8bit(int x) const { return -0x80 <= x && x < 0x80; } bool isByte(int x) const { return 0 <= x && x < 0x100; } bool isShiftCount(int x) const { return 0 <= x && x < 32; } void emit_byte(int x); // emit a single byte void emit_word(int x); // emit a 16-bit word (not a wordSize word!) void emit_long(jint x); // emit a 32-bit word (not a longSize word!) void emit_address(address x); // emit an address (not a longSize word!) // Instruction boundaries (required when emitting relocatable values). class InstructionMark: public StackObj { private: AbstractAssembler* _assm; public: InstructionMark(AbstractAssembler* assm) : _assm(assm) { assert(assm->inst_mark() == NULL, "overlapping instructions"); _assm->set_inst_mark(); } ~InstructionMark() { _assm->clear_inst_mark(); } }; friend class InstructionMark; #ifdef ASSERT // Make it return true on platforms which need to verify // instruction boundaries for some operations. inline static bool pd_check_instruction_mark(); #endif // Label functions void print(Label& L); public: // Creation AbstractAssembler(CodeBuffer* code); // save end pointer back to code buf. void sync(); // ensure buf contains all code (call this before using/copying the code) void flush(); // min and max values for signed immediate ranges static int min_simm(int nbits) { return -(intptr_t(1) << (nbits - 1)) ; } static int max_simm(int nbits) { return (intptr_t(1) << (nbits - 1)) - 1; } // Define some: static int min_simm10() { return min_simm(10); } static int min_simm13() { return min_simm(13); } static int min_simm16() { return min_simm(16); } // Test if x is within signed immediate range for nbits static bool is_simm(intptr_t x, int nbits) { return min_simm(nbits) <= x && x <= max_simm(nbits); } // Define some: static bool is_simm5( intptr_t x) { return is_simm(x, 5 ); } static bool is_simm8( intptr_t x) { return is_simm(x, 8 ); } static bool is_simm10(intptr_t x) { return is_simm(x, 10); } static bool is_simm11(intptr_t x) { return is_simm(x, 11); } static bool is_simm12(intptr_t x) { return is_simm(x, 12); } static bool is_simm13(intptr_t x) { return is_simm(x, 13); } static bool is_simm16(intptr_t x) { return is_simm(x, 16); } static bool is_simm26(intptr_t x) { return is_simm(x, 26); } static bool is_simm32(intptr_t x) { return is_simm(x, 32); } // Accessors CodeBuffer* code() const; // _code_section->outer() CodeSection* code_section() const { return _code_section; } int sect() const; // return _code_section->index() address pc() const { return _code_pos; } int offset() const { return _code_pos - _code_begin; } int locator() const; // CodeBuffer::locator(offset(), sect()) OopRecorder* oop_recorder() const { return _oop_recorder; } void set_oop_recorder(OopRecorder* r) { _oop_recorder = r; } address inst_mark() const; void set_inst_mark(); void clear_inst_mark(); // Constants in code void a_byte(int x); void a_long(jint x); void relocate(RelocationHolder const& rspec, int format = 0); void relocate( relocInfo::relocType rtype, int format = 0) { if (rtype != relocInfo::none) relocate(Relocation::spec_simple(rtype), format); } static int code_fill_byte(); // used to pad out odd-sized code buffers // Associate a comment with the current offset. It will be printed // along with the disassembly when printing nmethods. Currently // only supported in the instruction section of the code buffer. void block_comment(const char* comment); // Label functions void bind(Label& L); // binds an unbound label L to the current code position // Move to a different section in the same code buffer. void set_code_section(CodeSection* cs); // Inform assembler when generating stub code and relocation info address start_a_stub(int required_space); void end_a_stub(); // Ditto for constants. address start_a_const(int required_space, int required_align = sizeof(double)); void end_a_const(); // constants support address long_constant(jlong c) { address ptr = start_a_const(sizeof(c), sizeof(c)); if (ptr != NULL) { *(jlong*)ptr = c; _code_pos = ptr + sizeof(c); end_a_const(); } return ptr; } address double_constant(jdouble c) { address ptr = start_a_const(sizeof(c), sizeof(c)); if (ptr != NULL) { *(jdouble*)ptr = c; _code_pos = ptr + sizeof(c); end_a_const(); } return ptr; } address float_constant(jfloat c) { address ptr = start_a_const(sizeof(c), sizeof(c)); if (ptr != NULL) { *(jfloat*)ptr = c; _code_pos = ptr + sizeof(c); end_a_const(); } return ptr; } address address_constant(address c) { address ptr = start_a_const(sizeof(c), sizeof(c)); if (ptr != NULL) { *(address*)ptr = c; _code_pos = ptr + sizeof(c); end_a_const(); } return ptr; } address address_constant(address c, RelocationHolder const& rspec) { address ptr = start_a_const(sizeof(c), sizeof(c)); if (ptr != NULL) { relocate(rspec); *(address*)ptr = c; _code_pos = ptr + sizeof(c); end_a_const(); } return ptr; } // Bootstrapping aid to cope with delayed determination of constants. // Returns a static address which will eventually contain the constant. // The value zero (NULL) stands instead of a constant which is still uncomputed. // Thus, the eventual value of the constant must not be zero. // This is fine, since this is designed for embedding object field // offsets in code which must be generated before the object class is loaded. // Field offsets are never zero, since an object's header (mark word) // is located at offset zero. RegisterOrConstant delayed_value(int(*value_fn)(), Register tmp, int offset = 0) { return delayed_value_impl(delayed_value_addr(value_fn), tmp, offset); } RegisterOrConstant delayed_value(address(*value_fn)(), Register tmp, int offset = 0) { return delayed_value_impl(delayed_value_addr(value_fn), tmp, offset); } virtual RegisterOrConstant delayed_value_impl(intptr_t* delayed_value_addr, Register tmp, int offset) = 0; // Last overloading is platform-dependent; look in assembler_.cpp. static intptr_t* delayed_value_addr(int(*constant_fn)()); static intptr_t* delayed_value_addr(address(*constant_fn)()); static void update_delayed_values(); // Bang stack to trigger StackOverflowError at a safe location // implementation delegates to machine-specific bang_stack_with_offset void generate_stack_overflow_check( int frame_size_in_bytes ); virtual void bang_stack_with_offset(int offset) = 0; /** * A platform-dependent method to patch a jump instruction that refers * to this label. * * @param branch the location of the instruction to patch * @param masm the assembler which generated the branch */ void pd_patch_instruction(address branch, address target); #ifndef PRODUCT /** * Platform-dependent method of printing an instruction that needs to be * patched. * * @param branch the instruction to be patched in the buffer. */ static void pd_print_patched_instruction(address branch); #endif // PRODUCT }; #ifdef TARGET_ARCH_x86 # include "assembler_x86.hpp" #endif #ifdef TARGET_ARCH_sparc # include "assembler_sparc.hpp" #endif #ifdef TARGET_ARCH_zero # include "assembler_zero.hpp" #endif #ifdef TARGET_ARCH_arm # include "assembler_arm.hpp" #endif #ifdef TARGET_ARCH_ppc # include "assembler_ppc.hpp" #endif #endif // SHARE_VM_ASM_ASSEMBLER_HPP