Wed, 27 Apr 2016 01:25:04 +0800
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http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/
changeset: 6782:28b50d07f6f8
tag: jdk8u25-b17
1 /*
2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 #ifndef SHARE_VM_ASM_ASSEMBLER_HPP
26 #define SHARE_VM_ASM_ASSEMBLER_HPP
28 #include "asm/codeBuffer.hpp"
29 #include "code/oopRecorder.hpp"
30 #include "code/relocInfo.hpp"
31 #include "memory/allocation.hpp"
32 #include "utilities/debug.hpp"
33 #include "utilities/growableArray.hpp"
34 #include "utilities/top.hpp"
36 #ifdef TARGET_ARCH_x86
37 # include "register_x86.hpp"
38 # include "vm_version_x86.hpp"
39 #endif
40 #ifdef TARGET_ARCH_sparc
41 # include "register_sparc.hpp"
42 # include "vm_version_sparc.hpp"
43 #endif
44 #ifdef TARGET_ARCH_zero
45 # include "register_zero.hpp"
46 # include "vm_version_zero.hpp"
47 #endif
48 #ifdef TARGET_ARCH_arm
49 # include "register_arm.hpp"
50 # include "vm_version_arm.hpp"
51 #endif
52 #ifdef TARGET_ARCH_ppc
53 # include "register_ppc.hpp"
54 # include "vm_version_ppc.hpp"
55 #endif
57 // This file contains platform-independent assembler declarations.
59 class MacroAssembler;
60 class AbstractAssembler;
61 class Label;
63 /**
64 * Labels represent destinations for control transfer instructions. Such
65 * instructions can accept a Label as their target argument. A Label is
66 * bound to the current location in the code stream by calling the
67 * MacroAssembler's 'bind' method, which in turn calls the Label's 'bind'
68 * method. A Label may be referenced by an instruction before it's bound
69 * (i.e., 'forward referenced'). 'bind' stores the current code offset
70 * in the Label object.
71 *
72 * If an instruction references a bound Label, the offset field(s) within
73 * the instruction are immediately filled in based on the Label's code
74 * offset. If an instruction references an unbound label, that
75 * instruction is put on a list of instructions that must be patched
76 * (i.e., 'resolved') when the Label is bound.
77 *
78 * 'bind' will call the platform-specific 'patch_instruction' method to
79 * fill in the offset field(s) for each unresolved instruction (if there
80 * are any). 'patch_instruction' lives in one of the
81 * cpu/<arch>/vm/assembler_<arch>* files.
82 *
83 * Instead of using a linked list of unresolved instructions, a Label has
84 * an array of unresolved instruction code offsets. _patch_index
85 * contains the total number of forward references. If the Label's array
86 * overflows (i.e., _patch_index grows larger than the array size), a
87 * GrowableArray is allocated to hold the remaining offsets. (The cache
88 * size is 4 for now, which handles over 99.5% of the cases)
89 *
90 * Labels may only be used within a single CodeSection. If you need
91 * to create references between code sections, use explicit relocations.
92 */
93 class Label VALUE_OBJ_CLASS_SPEC {
94 private:
95 enum { PatchCacheSize = 4 };
97 // _loc encodes both the binding state (via its sign)
98 // and the binding locator (via its value) of a label.
99 //
100 // _loc >= 0 bound label, loc() encodes the target (jump) position
101 // _loc == -1 unbound label
102 int _loc;
104 // References to instructions that jump to this unresolved label.
105 // These instructions need to be patched when the label is bound
106 // using the platform-specific patchInstruction() method.
107 //
108 // To avoid having to allocate from the C-heap each time, we provide
109 // a local cache and use the overflow only if we exceed the local cache
110 int _patches[PatchCacheSize];
111 int _patch_index;
112 GrowableArray<int>* _patch_overflow;
114 Label(const Label&) { ShouldNotReachHere(); }
116 public:
118 /**
119 * After binding, be sure 'patch_instructions' is called later to link
120 */
121 void bind_loc(int loc) {
122 assert(loc >= 0, "illegal locator");
123 assert(_loc == -1, "already bound");
124 _loc = loc;
125 }
126 void bind_loc(int pos, int sect) { bind_loc(CodeBuffer::locator(pos, sect)); }
128 #ifndef PRODUCT
129 // Iterates over all unresolved instructions for printing
130 void print_instructions(MacroAssembler* masm) const;
131 #endif // PRODUCT
133 /**
134 * Returns the position of the the Label in the code buffer
135 * The position is a 'locator', which encodes both offset and section.
136 */
137 int loc() const {
138 assert(_loc >= 0, "unbound label");
139 return _loc;
140 }
141 int loc_pos() const { return CodeBuffer::locator_pos(loc()); }
142 int loc_sect() const { return CodeBuffer::locator_sect(loc()); }
144 bool is_bound() const { return _loc >= 0; }
145 bool is_unbound() const { return _loc == -1 && _patch_index > 0; }
146 bool is_unused() const { return _loc == -1 && _patch_index == 0; }
148 /**
149 * Adds a reference to an unresolved displacement instruction to
150 * this unbound label
151 *
152 * @param cb the code buffer being patched
153 * @param branch_loc the locator of the branch instruction in the code buffer
154 */
155 void add_patch_at(CodeBuffer* cb, int branch_loc);
157 /**
158 * Iterate over the list of patches, resolving the instructions
159 * Call patch_instruction on each 'branch_loc' value
160 */
161 void patch_instructions(MacroAssembler* masm);
163 void init() {
164 _loc = -1;
165 _patch_index = 0;
166 _patch_overflow = NULL;
167 }
169 Label() {
170 init();
171 }
172 };
174 // A union type for code which has to assemble both constant and
175 // non-constant operands, when the distinction cannot be made
176 // statically.
177 class RegisterOrConstant VALUE_OBJ_CLASS_SPEC {
178 private:
179 Register _r;
180 intptr_t _c;
182 public:
183 RegisterOrConstant(): _r(noreg), _c(0) {}
184 RegisterOrConstant(Register r): _r(r), _c(0) {}
185 RegisterOrConstant(intptr_t c): _r(noreg), _c(c) {}
187 Register as_register() const { assert(is_register(),""); return _r; }
188 intptr_t as_constant() const { assert(is_constant(),""); return _c; }
190 Register register_or_noreg() const { return _r; }
191 intptr_t constant_or_zero() const { return _c; }
193 bool is_register() const { return _r != noreg; }
194 bool is_constant() const { return _r == noreg; }
195 };
197 // The Abstract Assembler: Pure assembler doing NO optimizations on the
198 // instruction level; i.e., what you write is what you get.
199 // The Assembler is generating code into a CodeBuffer.
200 class AbstractAssembler : public ResourceObj {
201 friend class Label;
203 protected:
204 CodeSection* _code_section; // section within the code buffer
205 OopRecorder* _oop_recorder; // support for relocInfo::oop_type
207 public:
208 // Code emission & accessing
209 address addr_at(int pos) const { return code_section()->start() + pos; }
211 protected:
212 // This routine is called with a label is used for an address.
213 // Labels and displacements truck in offsets, but target must return a PC.
214 address target(Label& L) { return code_section()->target(L, pc()); }
216 bool is8bit(int x) const { return -0x80 <= x && x < 0x80; }
217 bool isByte(int x) const { return 0 <= x && x < 0x100; }
218 bool isShiftCount(int x) const { return 0 <= x && x < 32; }
220 // Instruction boundaries (required when emitting relocatable values).
221 class InstructionMark: public StackObj {
222 private:
223 AbstractAssembler* _assm;
225 public:
226 InstructionMark(AbstractAssembler* assm) : _assm(assm) {
227 assert(assm->inst_mark() == NULL, "overlapping instructions");
228 _assm->set_inst_mark();
229 }
230 ~InstructionMark() {
231 _assm->clear_inst_mark();
232 }
233 };
234 friend class InstructionMark;
235 #ifdef ASSERT
236 // Make it return true on platforms which need to verify
237 // instruction boundaries for some operations.
238 static bool pd_check_instruction_mark();
240 // Add delta to short branch distance to verify that it still fit into imm8.
241 int _short_branch_delta;
243 int short_branch_delta() const { return _short_branch_delta; }
244 void set_short_branch_delta() { _short_branch_delta = 32; }
245 void clear_short_branch_delta() { _short_branch_delta = 0; }
247 class ShortBranchVerifier: public StackObj {
248 private:
249 AbstractAssembler* _assm;
251 public:
252 ShortBranchVerifier(AbstractAssembler* assm) : _assm(assm) {
253 assert(assm->short_branch_delta() == 0, "overlapping instructions");
254 _assm->set_short_branch_delta();
255 }
256 ~ShortBranchVerifier() {
257 _assm->clear_short_branch_delta();
258 }
259 };
260 #else
261 // Dummy in product.
262 class ShortBranchVerifier: public StackObj {
263 public:
264 ShortBranchVerifier(AbstractAssembler* assm) {}
265 };
266 #endif
268 public:
270 // Creation
271 AbstractAssembler(CodeBuffer* code);
273 // ensure buf contains all code (call this before using/copying the code)
274 void flush();
276 void emit_int8( int8_t x) { code_section()->emit_int8( x); }
277 void emit_int16( int16_t x) { code_section()->emit_int16( x); }
278 void emit_int32( int32_t x) { code_section()->emit_int32( x); }
279 void emit_int64( int64_t x) { code_section()->emit_int64( x); }
281 void emit_float( jfloat x) { code_section()->emit_float( x); }
282 void emit_double( jdouble x) { code_section()->emit_double( x); }
283 void emit_address(address x) { code_section()->emit_address(x); }
285 // min and max values for signed immediate ranges
286 static int min_simm(int nbits) { return -(intptr_t(1) << (nbits - 1)) ; }
287 static int max_simm(int nbits) { return (intptr_t(1) << (nbits - 1)) - 1; }
289 // Define some:
290 static int min_simm10() { return min_simm(10); }
291 static int min_simm13() { return min_simm(13); }
292 static int min_simm16() { return min_simm(16); }
294 // Test if x is within signed immediate range for nbits
295 static bool is_simm(intptr_t x, int nbits) { return min_simm(nbits) <= x && x <= max_simm(nbits); }
297 // Define some:
298 static bool is_simm5( intptr_t x) { return is_simm(x, 5 ); }
299 static bool is_simm8( intptr_t x) { return is_simm(x, 8 ); }
300 static bool is_simm10(intptr_t x) { return is_simm(x, 10); }
301 static bool is_simm11(intptr_t x) { return is_simm(x, 11); }
302 static bool is_simm12(intptr_t x) { return is_simm(x, 12); }
303 static bool is_simm13(intptr_t x) { return is_simm(x, 13); }
304 static bool is_simm16(intptr_t x) { return is_simm(x, 16); }
305 static bool is_simm26(intptr_t x) { return is_simm(x, 26); }
306 static bool is_simm32(intptr_t x) { return is_simm(x, 32); }
308 // Accessors
309 CodeSection* code_section() const { return _code_section; }
310 CodeBuffer* code() const { return code_section()->outer(); }
311 int sect() const { return code_section()->index(); }
312 address pc() const { return code_section()->end(); }
313 int offset() const { return code_section()->size(); }
314 int locator() const { return CodeBuffer::locator(offset(), sect()); }
316 OopRecorder* oop_recorder() const { return _oop_recorder; }
317 void set_oop_recorder(OopRecorder* r) { _oop_recorder = r; }
319 address inst_mark() const { return code_section()->mark(); }
320 void set_inst_mark() { code_section()->set_mark(); }
321 void clear_inst_mark() { code_section()->clear_mark(); }
323 // Constants in code
324 void relocate(RelocationHolder const& rspec, int format = 0) {
325 assert(!pd_check_instruction_mark()
326 || inst_mark() == NULL || inst_mark() == code_section()->end(),
327 "call relocate() between instructions");
328 code_section()->relocate(code_section()->end(), rspec, format);
329 }
330 void relocate( relocInfo::relocType rtype, int format = 0) {
331 code_section()->relocate(code_section()->end(), rtype, format);
332 }
334 static int code_fill_byte(); // used to pad out odd-sized code buffers
336 // Associate a comment with the current offset. It will be printed
337 // along with the disassembly when printing nmethods. Currently
338 // only supported in the instruction section of the code buffer.
339 void block_comment(const char* comment);
340 // Copy str to a buffer that has the same lifetime as the CodeBuffer
341 const char* code_string(const char* str);
343 // Label functions
344 void bind(Label& L); // binds an unbound label L to the current code position
346 // Move to a different section in the same code buffer.
347 void set_code_section(CodeSection* cs);
349 // Inform assembler when generating stub code and relocation info
350 address start_a_stub(int required_space);
351 void end_a_stub();
352 // Ditto for constants.
353 address start_a_const(int required_space, int required_align = sizeof(double));
354 void end_a_const(CodeSection* cs); // Pass the codesection to continue in (insts or stubs?).
356 // constants support
357 //
358 // We must remember the code section (insts or stubs) in c1
359 // so we can reset to the proper section in end_a_const().
360 address long_constant(jlong c) {
361 CodeSection* c1 = _code_section;
362 address ptr = start_a_const(sizeof(c), sizeof(c));
363 if (ptr != NULL) {
364 emit_int64(c);
365 end_a_const(c1);
366 }
367 return ptr;
368 }
369 address double_constant(jdouble c) {
370 CodeSection* c1 = _code_section;
371 address ptr = start_a_const(sizeof(c), sizeof(c));
372 if (ptr != NULL) {
373 emit_double(c);
374 end_a_const(c1);
375 }
376 return ptr;
377 }
378 address float_constant(jfloat c) {
379 CodeSection* c1 = _code_section;
380 address ptr = start_a_const(sizeof(c), sizeof(c));
381 if (ptr != NULL) {
382 emit_float(c);
383 end_a_const(c1);
384 }
385 return ptr;
386 }
387 address address_constant(address c) {
388 CodeSection* c1 = _code_section;
389 address ptr = start_a_const(sizeof(c), sizeof(c));
390 if (ptr != NULL) {
391 emit_address(c);
392 end_a_const(c1);
393 }
394 return ptr;
395 }
396 address address_constant(address c, RelocationHolder const& rspec) {
397 CodeSection* c1 = _code_section;
398 address ptr = start_a_const(sizeof(c), sizeof(c));
399 if (ptr != NULL) {
400 relocate(rspec);
401 emit_address(c);
402 end_a_const(c1);
403 }
404 return ptr;
405 }
407 // Bootstrapping aid to cope with delayed determination of constants.
408 // Returns a static address which will eventually contain the constant.
409 // The value zero (NULL) stands instead of a constant which is still uncomputed.
410 // Thus, the eventual value of the constant must not be zero.
411 // This is fine, since this is designed for embedding object field
412 // offsets in code which must be generated before the object class is loaded.
413 // Field offsets are never zero, since an object's header (mark word)
414 // is located at offset zero.
415 RegisterOrConstant delayed_value(int(*value_fn)(), Register tmp, int offset = 0);
416 RegisterOrConstant delayed_value(address(*value_fn)(), Register tmp, int offset = 0);
417 virtual RegisterOrConstant delayed_value_impl(intptr_t* delayed_value_addr, Register tmp, int offset) = 0;
418 // Last overloading is platform-dependent; look in assembler_<arch>.cpp.
419 static intptr_t* delayed_value_addr(int(*constant_fn)());
420 static intptr_t* delayed_value_addr(address(*constant_fn)());
421 static void update_delayed_values();
423 // Bang stack to trigger StackOverflowError at a safe location
424 // implementation delegates to machine-specific bang_stack_with_offset
425 void generate_stack_overflow_check( int frame_size_in_bytes );
426 virtual void bang_stack_with_offset(int offset) = 0;
429 /**
430 * A platform-dependent method to patch a jump instruction that refers
431 * to this label.
432 *
433 * @param branch the location of the instruction to patch
434 * @param masm the assembler which generated the branch
435 */
436 void pd_patch_instruction(address branch, address target);
438 };
440 #ifdef TARGET_ARCH_x86
441 # include "assembler_x86.hpp"
442 #endif
443 #ifdef TARGET_ARCH_sparc
444 # include "assembler_sparc.hpp"
445 #endif
446 #ifdef TARGET_ARCH_zero
447 # include "assembler_zero.hpp"
448 #endif
449 #ifdef TARGET_ARCH_arm
450 # include "assembler_arm.hpp"
451 #endif
452 #ifdef TARGET_ARCH_ppc
453 # include "assembler_ppc.hpp"
454 #endif
457 #endif // SHARE_VM_ASM_ASSEMBLER_HPP