Mercurial > hg > graal-compiler
comparison src/share/vm/asm/assembler.hpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | 98cb887364d3 |
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1 /* | |
2 * Copyright 1997-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 // This file contains platform-independant assembler declarations. | |
26 | |
27 class CodeBuffer; | |
28 class MacroAssembler; | |
29 class AbstractAssembler; | |
30 class Label; | |
31 | |
32 /** | |
33 * Labels represent destinations for control transfer instructions. Such | |
34 * instructions can accept a Label as their target argument. A Label is | |
35 * bound to the current location in the code stream by calling the | |
36 * MacroAssembler's 'bind' method, which in turn calls the Label's 'bind' | |
37 * method. A Label may be referenced by an instruction before it's bound | |
38 * (i.e., 'forward referenced'). 'bind' stores the current code offset | |
39 * in the Label object. | |
40 * | |
41 * If an instruction references a bound Label, the offset field(s) within | |
42 * the instruction are immediately filled in based on the Label's code | |
43 * offset. If an instruction references an unbound label, that | |
44 * instruction is put on a list of instructions that must be patched | |
45 * (i.e., 'resolved') when the Label is bound. | |
46 * | |
47 * 'bind' will call the platform-specific 'patch_instruction' method to | |
48 * fill in the offset field(s) for each unresolved instruction (if there | |
49 * are any). 'patch_instruction' lives in one of the | |
50 * cpu/<arch>/vm/assembler_<arch>* files. | |
51 * | |
52 * Instead of using a linked list of unresolved instructions, a Label has | |
53 * an array of unresolved instruction code offsets. _patch_index | |
54 * contains the total number of forward references. If the Label's array | |
55 * overflows (i.e., _patch_index grows larger than the array size), a | |
56 * GrowableArray is allocated to hold the remaining offsets. (The cache | |
57 * size is 4 for now, which handles over 99.5% of the cases) | |
58 * | |
59 * Labels may only be used within a single CodeSection. If you need | |
60 * to create references between code sections, use explicit relocations. | |
61 */ | |
62 class Label VALUE_OBJ_CLASS_SPEC { | |
63 private: | |
64 enum { PatchCacheSize = 4 }; | |
65 | |
66 // _loc encodes both the binding state (via its sign) | |
67 // and the binding locator (via its value) of a label. | |
68 // | |
69 // _loc >= 0 bound label, loc() encodes the target (jump) position | |
70 // _loc == -1 unbound label | |
71 int _loc; | |
72 | |
73 // References to instructions that jump to this unresolved label. | |
74 // These instructions need to be patched when the label is bound | |
75 // using the platform-specific patchInstruction() method. | |
76 // | |
77 // To avoid having to allocate from the C-heap each time, we provide | |
78 // a local cache and use the overflow only if we exceed the local cache | |
79 int _patches[PatchCacheSize]; | |
80 int _patch_index; | |
81 GrowableArray<int>* _patch_overflow; | |
82 | |
83 Label(const Label&) { ShouldNotReachHere(); } | |
84 | |
85 public: | |
86 | |
87 /** | |
88 * After binding, be sure 'patch_instructions' is called later to link | |
89 */ | |
90 void bind_loc(int loc) { | |
91 assert(loc >= 0, "illegal locator"); | |
92 assert(_loc == -1, "already bound"); | |
93 _loc = loc; | |
94 } | |
95 void bind_loc(int pos, int sect); // = bind_loc(locator(pos, sect)) | |
96 | |
97 #ifndef PRODUCT | |
98 // Iterates over all unresolved instructions for printing | |
99 void print_instructions(MacroAssembler* masm) const; | |
100 #endif // PRODUCT | |
101 | |
102 /** | |
103 * Returns the position of the the Label in the code buffer | |
104 * The position is a 'locator', which encodes both offset and section. | |
105 */ | |
106 int loc() const { | |
107 assert(_loc >= 0, "unbound label"); | |
108 return _loc; | |
109 } | |
110 int loc_pos() const; // == locator_pos(loc()) | |
111 int loc_sect() const; // == locator_sect(loc()) | |
112 | |
113 bool is_bound() const { return _loc >= 0; } | |
114 bool is_unbound() const { return _loc == -1 && _patch_index > 0; } | |
115 bool is_unused() const { return _loc == -1 && _patch_index == 0; } | |
116 | |
117 /** | |
118 * Adds a reference to an unresolved displacement instruction to | |
119 * this unbound label | |
120 * | |
121 * @param cb the code buffer being patched | |
122 * @param branch_loc the locator of the branch instruction in the code buffer | |
123 */ | |
124 void add_patch_at(CodeBuffer* cb, int branch_loc); | |
125 | |
126 /** | |
127 * Iterate over the list of patches, resolving the instructions | |
128 * Call patch_instruction on each 'branch_loc' value | |
129 */ | |
130 void patch_instructions(MacroAssembler* masm); | |
131 | |
132 void init() { | |
133 _loc = -1; | |
134 _patch_index = 0; | |
135 _patch_overflow = NULL; | |
136 } | |
137 | |
138 Label() { | |
139 init(); | |
140 } | |
141 }; | |
142 | |
143 | |
144 // The Abstract Assembler: Pure assembler doing NO optimizations on the | |
145 // instruction level; i.e., what you write is what you get. | |
146 // The Assembler is generating code into a CodeBuffer. | |
147 class AbstractAssembler : public ResourceObj { | |
148 friend class Label; | |
149 | |
150 protected: | |
151 CodeSection* _code_section; // section within the code buffer | |
152 address _code_begin; // first byte of code buffer | |
153 address _code_limit; // first byte after code buffer | |
154 address _code_pos; // current code generation position | |
155 OopRecorder* _oop_recorder; // support for relocInfo::oop_type | |
156 | |
157 // Code emission & accessing | |
158 address addr_at(int pos) const { return _code_begin + pos; } | |
159 | |
160 // This routine is called with a label is used for an address. | |
161 // Labels and displacements truck in offsets, but target must return a PC. | |
162 address target(Label& L); // return _code_section->target(L) | |
163 | |
164 bool is8bit(int x) const { return -0x80 <= x && x < 0x80; } | |
165 bool isByte(int x) const { return 0 <= x && x < 0x100; } | |
166 bool isShiftCount(int x) const { return 0 <= x && x < 32; } | |
167 | |
168 void emit_byte(int x); // emit a single byte | |
169 void emit_word(int x); // emit a 16-bit word (not a wordSize word!) | |
170 void emit_long(jint x); // emit a 32-bit word (not a longSize word!) | |
171 void emit_address(address x); // emit an address (not a longSize word!) | |
172 | |
173 // Instruction boundaries (required when emitting relocatable values). | |
174 class InstructionMark: public StackObj { | |
175 private: | |
176 AbstractAssembler* _assm; | |
177 | |
178 public: | |
179 InstructionMark(AbstractAssembler* assm) : _assm(assm) { | |
180 assert(assm->inst_mark() == NULL, "overlapping instructions"); | |
181 _assm->set_inst_mark(); | |
182 } | |
183 ~InstructionMark() { | |
184 _assm->clear_inst_mark(); | |
185 } | |
186 }; | |
187 friend class InstructionMark; | |
188 #ifdef ASSERT | |
189 // Make it return true on platforms which need to verify | |
190 // instruction boundaries for some operations. | |
191 inline static bool pd_check_instruction_mark(); | |
192 #endif | |
193 | |
194 // Label functions | |
195 void print(Label& L); | |
196 | |
197 public: | |
198 | |
199 // Creation | |
200 AbstractAssembler(CodeBuffer* code); | |
201 | |
202 // save end pointer back to code buf. | |
203 void sync(); | |
204 | |
205 // ensure buf contains all code (call this before using/copying the code) | |
206 void flush(); | |
207 | |
208 // Accessors | |
209 CodeBuffer* code() const; // _code_section->outer() | |
210 CodeSection* code_section() const { return _code_section; } | |
211 int sect() const; // return _code_section->index() | |
212 address pc() const { return _code_pos; } | |
213 int offset() const { return _code_pos - _code_begin; } | |
214 int locator() const; // CodeBuffer::locator(offset(), sect()) | |
215 OopRecorder* oop_recorder() const { return _oop_recorder; } | |
216 void set_oop_recorder(OopRecorder* r) { _oop_recorder = r; } | |
217 | |
218 address inst_mark() const; | |
219 void set_inst_mark(); | |
220 void clear_inst_mark(); | |
221 | |
222 // Constants in code | |
223 void a_byte(int x); | |
224 void a_long(jint x); | |
225 void relocate(RelocationHolder const& rspec, int format = 0); | |
226 void relocate( relocInfo::relocType rtype, int format = 0) { | |
227 if (rtype != relocInfo::none) | |
228 relocate(Relocation::spec_simple(rtype), format); | |
229 } | |
230 | |
231 static int code_fill_byte(); // used to pad out odd-sized code buffers | |
232 | |
233 // Associate a comment with the current offset. It will be printed | |
234 // along with the disassembly when printing nmethods. Currently | |
235 // only supported in the instruction section of the code buffer. | |
236 void block_comment(const char* comment); | |
237 | |
238 // Label functions | |
239 void bind(Label& L); // binds an unbound label L to the current code position | |
240 | |
241 // Move to a different section in the same code buffer. | |
242 void set_code_section(CodeSection* cs); | |
243 | |
244 // Inform assembler when generating stub code and relocation info | |
245 address start_a_stub(int required_space); | |
246 void end_a_stub(); | |
247 // Ditto for constants. | |
248 address start_a_const(int required_space, int required_align = sizeof(double)); | |
249 void end_a_const(); | |
250 | |
251 // fp constants support | |
252 address double_constant(jdouble c) { | |
253 address ptr = start_a_const(sizeof(c), sizeof(c)); | |
254 if (ptr != NULL) { | |
255 *(jdouble*)ptr = c; | |
256 _code_pos = ptr + sizeof(c); | |
257 end_a_const(); | |
258 } | |
259 return ptr; | |
260 } | |
261 address float_constant(jfloat c) { | |
262 address ptr = start_a_const(sizeof(c), sizeof(c)); | |
263 if (ptr != NULL) { | |
264 *(jfloat*)ptr = c; | |
265 _code_pos = ptr + sizeof(c); | |
266 end_a_const(); | |
267 } | |
268 return ptr; | |
269 } | |
270 address address_constant(address c, RelocationHolder const& rspec) { | |
271 address ptr = start_a_const(sizeof(c), sizeof(c)); | |
272 if (ptr != NULL) { | |
273 relocate(rspec); | |
274 *(address*)ptr = c; | |
275 _code_pos = ptr + sizeof(c); | |
276 end_a_const(); | |
277 } | |
278 return ptr; | |
279 } | |
280 inline address address_constant(Label& L); | |
281 inline address address_table_constant(GrowableArray<Label*> label); | |
282 | |
283 // Bang stack to trigger StackOverflowError at a safe location | |
284 // implementation delegates to machine-specific bang_stack_with_offset | |
285 void generate_stack_overflow_check( int frame_size_in_bytes ); | |
286 virtual void bang_stack_with_offset(int offset) = 0; | |
287 | |
288 | |
289 /** | |
290 * A platform-dependent method to patch a jump instruction that refers | |
291 * to this label. | |
292 * | |
293 * @param branch the location of the instruction to patch | |
294 * @param masm the assembler which generated the branch | |
295 */ | |
296 void pd_patch_instruction(address branch, address target); | |
297 | |
298 #ifndef PRODUCT | |
299 /** | |
300 * Platform-dependent method of printing an instruction that needs to be | |
301 * patched. | |
302 * | |
303 * @param branch the instruction to be patched in the buffer. | |
304 */ | |
305 static void pd_print_patched_instruction(address branch); | |
306 #endif // PRODUCT | |
307 }; | |
308 | |
309 #include "incls/_assembler_pd.hpp.incl" |