1 /*
2 * Copyright (c) 1997, 2018, 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 */
24
25 #ifndef SHARE_VM_ASM_ASSEMBLER_HPP
26 #define SHARE_VM_ASM_ASSEMBLER_HPP
27
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"
35
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
56 #ifdef TARGET_ARCH_aarch64
57 # include "register_aarch64.hpp"
58 # include "vm_version_aarch64.hpp"
59 #endif
60
61 // This file contains platform-independent assembler declarations.
62
63 class MacroAssembler;
64 class AbstractAssembler;
65 class Label;
66
67 /**
68 * Labels represent destinations for control transfer instructions. Such
69 * instructions can accept a Label as their target argument. A Label is
70 * bound to the current location in the code stream by calling the
71 * MacroAssembler's 'bind' method, which in turn calls the Label's 'bind'
72 * method. A Label may be referenced by an instruction before it's bound
73 * (i.e., 'forward referenced'). 'bind' stores the current code offset
74 * in the Label object.
75 *
76 * If an instruction references a bound Label, the offset field(s) within
77 * the instruction are immediately filled in based on the Label's code
78 * offset. If an instruction references an unbound label, that
79 * instruction is put on a list of instructions that must be patched
80 * (i.e., 'resolved') when the Label is bound.
81 *
82 * 'bind' will call the platform-specific 'patch_instruction' method to
83 * fill in the offset field(s) for each unresolved instruction (if there
84 * are any). 'patch_instruction' lives in one of the
85 * cpu/<arch>/vm/assembler_<arch>* files.
86 *
87 * Instead of using a linked list of unresolved instructions, a Label has
88 * an array of unresolved instruction code offsets. _patch_index
89 * contains the total number of forward references. If the Label's array
90 * overflows (i.e., _patch_index grows larger than the array size), a
91 * GrowableArray is allocated to hold the remaining offsets. (The cache
92 * size is 4 for now, which handles over 99.5% of the cases)
93 *
94 * Labels may only be used within a single CodeSection. If you need
95 * to create references between code sections, use explicit relocations.
96 */
97 class Label VALUE_OBJ_CLASS_SPEC {
98 private:
99 enum { PatchCacheSize = 4 };
100
101 // _loc encodes both the binding state (via its sign)
102 // and the binding locator (via its value) of a label.
103 //
104 // _loc >= 0 bound label, loc() encodes the target (jump) position
105 // _loc == -1 unbound label
106 int _loc;
107
108 // References to instructions that jump to this unresolved label.
109 // These instructions need to be patched when the label is bound
110 // using the platform-specific patchInstruction() method.
111 //
112 // To avoid having to allocate from the C-heap each time, we provide
113 // a local cache and use the overflow only if we exceed the local cache
114 int _patches[PatchCacheSize];
115 int _patch_index;
116 GrowableArray<int>* _patch_overflow;
117
118 Label(const Label&) { ShouldNotReachHere(); }
119
120 public:
121
122 /**
123 * After binding, be sure 'patch_instructions' is called later to link
124 */
125 void bind_loc(int loc) {
126 assert(loc >= 0, "illegal locator");
127 assert(_loc == -1, "already bound");
128 _loc = loc;
129 }
130 void bind_loc(int pos, int sect) { bind_loc(CodeBuffer::locator(pos, sect)); }
131
132 #ifndef PRODUCT
133 // Iterates over all unresolved instructions for printing
134 void print_instructions(MacroAssembler* masm) const;
135 #endif // PRODUCT
136
137 /**
138 * Returns the position of the the Label in the code buffer
139 * The position is a 'locator', which encodes both offset and section.
140 */
141 int loc() const {
142 assert(_loc >= 0, "unbound label");
143 return _loc;
144 }
145 int loc_pos() const { return CodeBuffer::locator_pos(loc()); }
146 int loc_sect() const { return CodeBuffer::locator_sect(loc()); }
147
148 bool is_bound() const { return _loc >= 0; }
149 bool is_unbound() const { return _loc == -1 && _patch_index > 0; }
150 bool is_unused() const { return _loc == -1 && _patch_index == 0; }
151
152 /**
153 * Adds a reference to an unresolved displacement instruction to
154 * this unbound label
155 *
156 * @param cb the code buffer being patched
157 * @param branch_loc the locator of the branch instruction in the code buffer
158 */
159 void add_patch_at(CodeBuffer* cb, int branch_loc);
160
161 /**
162 * Iterate over the list of patches, resolving the instructions
163 * Call patch_instruction on each 'branch_loc' value
164 */
165 void patch_instructions(MacroAssembler* masm);
166
167 void init() {
168 _loc = -1;
169 _patch_index = 0;
170 _patch_overflow = NULL;
171 }
172
173 Label() {
174 init();
175 }
176
177 ~Label() {
178 assert(is_bound() || is_unused(), "Label was never bound to a location, but it was used as a jmp target");
179 }
180
181 void reset() {
182 init(); //leave _patch_overflow because it points to CodeBuffer.
183 }
184 };
185
186 // A union type for code which has to assemble both constant and
187 // non-constant operands, when the distinction cannot be made
188 // statically.
189 class RegisterOrConstant VALUE_OBJ_CLASS_SPEC {
190 private:
191 Register _r;
192 intptr_t _c;
193
194 public:
195 RegisterOrConstant(): _r(noreg), _c(0) {}
196 RegisterOrConstant(Register r): _r(r), _c(0) {}
197 RegisterOrConstant(intptr_t c): _r(noreg), _c(c) {}
198
199 Register as_register() const { assert(is_register(),""); return _r; }
200 intptr_t as_constant() const { assert(is_constant(),""); return _c; }
201
202 Register register_or_noreg() const { return _r; }
203 intptr_t constant_or_zero() const { return _c; }
204
205 bool is_register() const { return _r != noreg; }
206 bool is_constant() const { return _r == noreg; }
207 };
208
209 // The Abstract Assembler: Pure assembler doing NO optimizations on the
210 // instruction level; i.e., what you write is what you get.
211 // The Assembler is generating code into a CodeBuffer.
212 class AbstractAssembler : public ResourceObj {
213 friend class Label;
214
215 protected:
216 CodeSection* _code_section; // section within the code buffer
217 OopRecorder* _oop_recorder; // support for relocInfo::oop_type
218
219 public:
220 // Code emission & accessing
221 address addr_at(int pos) const { return code_section()->start() + pos; }
222
223 protected:
224 // This routine is called with a label is used for an address.
225 // Labels and displacements truck in offsets, but target must return a PC.
226 address target(Label& L) { return code_section()->target(L, pc()); }
227
228 bool is8bit(int x) const { return -0x80 <= x && x < 0x80; }
229 bool isByte(int x) const { return 0 <= x && x < 0x100; }
230 bool isShiftCount(int x) const { return 0 <= x && x < 32; }
231
232 // Instruction boundaries (required when emitting relocatable values).
233 class InstructionMark: public StackObj {
234 private:
235 AbstractAssembler* _assm;
236
237 public:
238 InstructionMark(AbstractAssembler* assm) : _assm(assm) {
239 assert(assm->inst_mark() == NULL, "overlapping instructions");
240 _assm->set_inst_mark();
241 }
242 ~InstructionMark() {
243 _assm->clear_inst_mark();
244 }
245 };
246 friend class InstructionMark;
247 #ifdef ASSERT
248 // Make it return true on platforms which need to verify
249 // instruction boundaries for some operations.
250 static bool pd_check_instruction_mark();
251
252 // Add delta to short branch distance to verify that it still fit into imm8.
253 int _short_branch_delta;
254
255 int short_branch_delta() const { return _short_branch_delta; }
256 void set_short_branch_delta() { _short_branch_delta = 32; }
257 void clear_short_branch_delta() { _short_branch_delta = 0; }
258
259 class ShortBranchVerifier: public StackObj {
260 private:
261 AbstractAssembler* _assm;
262
263 public:
264 ShortBranchVerifier(AbstractAssembler* assm) : _assm(assm) {
265 assert(assm->short_branch_delta() == 0, "overlapping instructions");
266 _assm->set_short_branch_delta();
267 }
268 ~ShortBranchVerifier() {
269 _assm->clear_short_branch_delta();
270 }
271 };
272 #else
273 // Dummy in product.
274 class ShortBranchVerifier: public StackObj {
275 public:
276 ShortBranchVerifier(AbstractAssembler* assm) {}
277 };
278 #endif
279
280 public:
281
282 // Creation
283 AbstractAssembler(CodeBuffer* code);
284
285 // ensure buf contains all code (call this before using/copying the code)
286 void flush();
287
288 void emit_int8( int8_t x) { code_section()->emit_int8( x); }
289 void emit_int16( int16_t x) { code_section()->emit_int16( x); }
290 void emit_int32( int32_t x) { code_section()->emit_int32( x); }
291 void emit_int64( int64_t x) { code_section()->emit_int64( x); }
292
293 void emit_float( jfloat x) { code_section()->emit_float( x); }
294 void emit_double( jdouble x) { code_section()->emit_double( x); }
295 void emit_address(address x) { code_section()->emit_address(x); }
296
297 // min and max values for signed immediate ranges
298 static int min_simm(int nbits) { return -(intptr_t(1) << (nbits - 1)) ; }
299 static int max_simm(int nbits) { return (intptr_t(1) << (nbits - 1)) - 1; }
300
301 // Define some:
302 static int min_simm10() { return min_simm(10); }
303 static int min_simm13() { return min_simm(13); }
304 static int min_simm16() { return min_simm(16); }
305
306 // Test if x is within signed immediate range for nbits
307 static bool is_simm(intptr_t x, int nbits) { return min_simm(nbits) <= x && x <= max_simm(nbits); }
308
309 // Define some:
310 static bool is_simm5( intptr_t x) { return is_simm(x, 5 ); }
311 static bool is_simm8( intptr_t x) { return is_simm(x, 8 ); }
312 static bool is_simm10(intptr_t x) { return is_simm(x, 10); }
313 static bool is_simm11(intptr_t x) { return is_simm(x, 11); }
314 static bool is_simm12(intptr_t x) { return is_simm(x, 12); }
315 static bool is_simm13(intptr_t x) { return is_simm(x, 13); }
316 static bool is_simm16(intptr_t x) { return is_simm(x, 16); }
317 static bool is_simm26(intptr_t x) { return is_simm(x, 26); }
318 static bool is_simm32(intptr_t x) { return is_simm(x, 32); }
319
320 // Accessors
321 CodeSection* code_section() const { return _code_section; }
322 CodeBuffer* code() const { return code_section()->outer(); }
323 int sect() const { return code_section()->index(); }
324 address pc() const { return code_section()->end(); }
325 int offset() const { return code_section()->size(); }
326 int locator() const { return CodeBuffer::locator(offset(), sect()); }
327
328 OopRecorder* oop_recorder() const { return _oop_recorder; }
329 void set_oop_recorder(OopRecorder* r) { _oop_recorder = r; }
330
331 address inst_mark() const { return code_section()->mark(); }
332 void set_inst_mark() { code_section()->set_mark(); }
333 void clear_inst_mark() { code_section()->clear_mark(); }
334
335 // Constants in code
336 void relocate(RelocationHolder const& rspec, int format = 0) {
337 assert(!pd_check_instruction_mark()
338 || inst_mark() == NULL || inst_mark() == code_section()->end(),
339 "call relocate() between instructions");
340 code_section()->relocate(code_section()->end(), rspec, format);
341 }
342 void relocate( relocInfo::relocType rtype, int format = 0) {
343 code_section()->relocate(code_section()->end(), rtype, format);
344 }
345
346 static int code_fill_byte(); // used to pad out odd-sized code buffers
347
348 // Associate a comment with the current offset. It will be printed
349 // along with the disassembly when printing nmethods. Currently
350 // only supported in the instruction section of the code buffer.
351 void block_comment(const char* comment);
352 // Copy str to a buffer that has the same lifetime as the CodeBuffer
353 const char* code_string(const char* str);
354
355 // Label functions
356 void bind(Label& L); // binds an unbound label L to the current code position
357
358 // Move to a different section in the same code buffer.
359 void set_code_section(CodeSection* cs);
360
361 // Inform assembler when generating stub code and relocation info
362 address start_a_stub(int required_space);
363 void end_a_stub();
364 // Ditto for constants.
365 address start_a_const(int required_space, int required_align = sizeof(double));
366 void end_a_const(CodeSection* cs); // Pass the codesection to continue in (insts or stubs?).
367
368 // constants support
369 //
370 // We must remember the code section (insts or stubs) in c1
371 // so we can reset to the proper section in end_a_const().
372 address long_constant(jlong c) {
373 CodeSection* c1 = _code_section;
374 address ptr = start_a_const(sizeof(c), sizeof(c));
375 if (ptr != NULL) {
376 emit_int64(c);
377 end_a_const(c1);
378 }
379 return ptr;
380 }
381 address double_constant(jdouble c) {
382 CodeSection* c1 = _code_section;
383 address ptr = start_a_const(sizeof(c), sizeof(c));
384 if (ptr != NULL) {
385 emit_double(c);
386 end_a_const(c1);
387 }
388 return ptr;
389 }
390 address float_constant(jfloat c) {
391 CodeSection* c1 = _code_section;
392 address ptr = start_a_const(sizeof(c), sizeof(c));
393 if (ptr != NULL) {
394 emit_float(c);
395 end_a_const(c1);
396 }
397 return ptr;
398 }
399 address address_constant(address c) {
400 CodeSection* c1 = _code_section;
401 address ptr = start_a_const(sizeof(c), sizeof(c));
402 if (ptr != NULL) {
403 emit_address(c);
404 end_a_const(c1);
405 }
406 return ptr;
407 }
408 address address_constant(address c, RelocationHolder const& rspec) {
409 CodeSection* c1 = _code_section;
410 address ptr = start_a_const(sizeof(c), sizeof(c));
411 if (ptr != NULL) {
412 relocate(rspec);
413 emit_address(c);
414 end_a_const(c1);
415 }
416 return ptr;
417 }
418
419 // Bootstrapping aid to cope with delayed determination of constants.
420 // Returns a static address which will eventually contain the constant.
421 // The value zero (NULL) stands instead of a constant which is still uncomputed.
422 // Thus, the eventual value of the constant must not be zero.
423 // This is fine, since this is designed for embedding object field
424 // offsets in code which must be generated before the object class is loaded.
425 // Field offsets are never zero, since an object's header (mark word)
426 // is located at offset zero.
427 RegisterOrConstant delayed_value(int(*value_fn)(), Register tmp, int offset = 0);
428 RegisterOrConstant delayed_value(address(*value_fn)(), Register tmp, int offset = 0);
429 virtual RegisterOrConstant delayed_value_impl(intptr_t* delayed_value_addr, Register tmp, int offset) = 0;
430 // Last overloading is platform-dependent; look in assembler_<arch>.cpp.
431 static intptr_t* delayed_value_addr(int(*constant_fn)());
432 static intptr_t* delayed_value_addr(address(*constant_fn)());
433 static void update_delayed_values();
434
435 // Bang stack to trigger StackOverflowError at a safe location
436 // implementation delegates to machine-specific bang_stack_with_offset
437 void generate_stack_overflow_check( int frame_size_in_bytes );
438 virtual void bang_stack_with_offset(int offset) = 0;
439
440
441 /**
442 * A platform-dependent method to patch a jump instruction that refers
443 * to this label.
444 *
445 * @param branch the location of the instruction to patch
446 * @param masm the assembler which generated the branch
447 */
448 void pd_patch_instruction(address branch, address target);
449
450 };
451
452 #ifdef TARGET_ARCH_x86
453 # include "assembler_x86.hpp"
454 #endif
455 #ifdef TARGET_ARCH_aarch64
456 # include "assembler_aarch64.hpp"
457 #endif
458 #ifdef TARGET_ARCH_sparc
459 # include "assembler_sparc.hpp"
460 #endif
461 #ifdef TARGET_ARCH_zero
462 # include "assembler_zero.hpp"
463 #endif
464 #ifdef TARGET_ARCH_arm
465 # include "assembler_arm.hpp"
466 #endif
467 #ifdef TARGET_ARCH_ppc
468 # include "assembler_ppc.hpp"
469 #endif
470
471
472 #endif // SHARE_VM_ASM_ASSEMBLER_HPP