1 /*
2 * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2012, 2015 SAP SE. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "asm/macroAssembler.inline.hpp"
28 #include "code/compiledIC.hpp"
29 #include "code/icBuffer.hpp"
30 #include "code/nmethod.hpp"
31 #include "memory/resourceArea.hpp"
32 #include "runtime/mutexLocker.hpp"
33 #include "runtime/safepoint.hpp"
34 #ifdef COMPILER2
35 #include "opto/matcher.hpp"
36 #endif
37
38 // ----------------------------------------------------------------------------
39
40 // A PPC CompiledDirectStaticCall looks like this:
41 //
42 // >>>> consts
43 //
44 // [call target1]
45 // [IC cache]
46 // [call target2]
47 //
48 // <<<< consts
49 // >>>> insts
50 //
51 // bl offset16 -+ -+ ??? // How many bits available?
52 // | |
53 // <<<< insts | |
54 // >>>> stubs | |
55 // | |- trampoline_stub_Reloc
56 // trampoline stub: | <-+
57 // r2 = toc |
58 // r2 = [r2 + offset] | // Load call target1 from const section
59 // mtctr r2 |
60 // bctr |- static_stub_Reloc
61 // comp_to_interp_stub: <---+
62 // r1 = toc
63 // ICreg = [r1 + IC_offset] // Load IC from const section
64 // r1 = [r1 + offset] // Load call target2 from const section
65 // mtctr r1
66 // bctr
67 //
68 // <<<< stubs
69 //
70 // The call instruction in the code either
71 // - branches directly to a compiled method if offset encodable in instruction
72 // - branches to the trampoline stub if offset to compiled method not encodable
73 // - branches to the compiled_to_interp stub if target interpreted
74 //
75 // Further there are three relocations from the loads to the constants in
76 // the constant section.
77 //
78 // Usage of r1 and r2 in the stubs allows to distinguish them.
79
80 const int IC_pos_in_java_to_interp_stub = 8;
81 #define __ _masm.
82 address CompiledStaticCall::emit_to_interp_stub(CodeBuffer &cbuf, address mark/* = NULL*/) {
83 #ifdef COMPILER2
84 if (mark == NULL) {
85 // Get the mark within main instrs section which is set to the address of the call.
86 mark = cbuf.insts_mark();
87 }
88
89 // Note that the code buffer's insts_mark is always relative to insts.
90 // That's why we must use the macroassembler to generate a stub.
91 MacroAssembler _masm(&cbuf);
92
93 // Start the stub.
94 address stub = __ start_a_stub(CompiledStaticCall::to_interp_stub_size());
95 if (stub == NULL) {
96 return NULL; // CodeCache is full
97 }
98
99 // For java_to_interp stubs we use R11_scratch1 as scratch register
100 // and in call trampoline stubs we use R12_scratch2. This way we
101 // can distinguish them (see is_NativeCallTrampolineStub_at()).
102 Register reg_scratch = R11_scratch1;
103
104 // Create a static stub relocation which relates this stub
105 // with the call instruction at insts_call_instruction_offset in the
106 // instructions code-section.
107 __ relocate(static_stub_Relocation::spec(mark));
108 const int stub_start_offset = __ offset();
109
110 // Now, create the stub's code:
111 // - load the TOC
112 // - load the inline cache oop from the constant pool
113 // - load the call target from the constant pool
114 // - call
115 __ calculate_address_from_global_toc(reg_scratch, __ method_toc());
116 AddressLiteral ic = __ allocate_metadata_address((Metadata *)NULL);
117 bool success = __ load_const_from_method_toc(as_Register(Matcher::inline_cache_reg_encode()),
118 ic, reg_scratch, /*fixed_size*/ true);
119 if (!success) {
120 return NULL; // CodeCache is full
121 }
122
123 if (ReoptimizeCallSequences) {
124 __ b64_patchable((address)-1, relocInfo::none);
125 } else {
126 AddressLiteral a((address)-1);
127 success = __ load_const_from_method_toc(reg_scratch, a, reg_scratch, /*fixed_size*/ true);
128 if (!success) {
129 return NULL; // CodeCache is full
130 }
131 __ mtctr(reg_scratch);
132 __ bctr();
133 }
134
135 // FIXME: Assert that the stub can be identified and patched.
136
137 // Java_to_interp_stub_size should be good.
138 assert((__ offset() - stub_start_offset) <= CompiledStaticCall::to_interp_stub_size(),
139 "should be good size");
140 assert(!is_NativeCallTrampolineStub_at(__ addr_at(stub_start_offset)),
141 "must not confuse java_to_interp with trampoline stubs");
142
143 // End the stub.
144 __ end_a_stub();
145 return stub;
146 #else
147 ShouldNotReachHere();
148 return NULL;
149 #endif
150 }
151 #undef __
152
153 // Size of java_to_interp stub, this doesn't need to be accurate but it must
154 // be larger or equal to the real size of the stub.
155 // Used for optimization in Compile::Shorten_branches.
156 int CompiledStaticCall::to_interp_stub_size() {
157 return 12 * BytesPerInstWord;
158 }
159
160 // Relocation entries for call stub, compiled java to interpreter.
161 // Used for optimization in Compile::Shorten_branches.
162 int CompiledStaticCall::reloc_to_interp_stub() {
163 return 5;
164 }
165
166 void CompiledDirectStaticCall::set_to_interpreted(methodHandle callee, address entry) {
167 address stub = find_stub(/*is_aot*/ false);
168 guarantee(stub != NULL, "stub not found");
169
170 if (TraceICs) {
171 ResourceMark rm;
172 tty->print_cr("CompiledDirectStaticCall@" INTPTR_FORMAT ": set_to_interpreted %s",
173 p2i(instruction_address()),
174 callee->name_and_sig_as_C_string());
175 }
176
177 // Creation also verifies the object.
178 NativeMovConstReg* method_holder = nativeMovConstReg_at(stub + IC_pos_in_java_to_interp_stub);
179 NativeJump* jump = nativeJump_at(method_holder->next_instruction_address());
180
181 #ifdef ASSERT
182 // read the value once
183 volatile intptr_t data = method_holder->data();
184 volatile address destination = jump->jump_destination();
185 assert(data == 0 || data == (intptr_t)callee(),
186 "a) MT-unsafe modification of inline cache");
187 assert(destination == (address)-1 || destination == entry,
188 "b) MT-unsafe modification of inline cache");
189 #endif
190
191 // Update stub.
192 method_holder->set_data((intptr_t)callee());
193 jump->set_jump_destination(entry);
194
195 // Update jump to call.
196 set_destination_mt_safe(stub);
197 }
198
199 void CompiledDirectStaticCall::set_stub_to_clean(static_stub_Relocation* static_stub) {
200 assert (CompiledIC_lock->is_locked() || SafepointSynchronize::is_at_safepoint(), "mt unsafe call");
201 // Reset stub.
202 address stub = static_stub->addr();
203 assert(stub != NULL, "stub not found");
204 // Creation also verifies the object.
205 NativeMovConstReg* method_holder = nativeMovConstReg_at(stub + IC_pos_in_java_to_interp_stub);
206 NativeJump* jump = nativeJump_at(method_holder->next_instruction_address());
207 method_holder->set_data(0);
208 jump->set_jump_destination((address)-1);
209 }
210
211 //-----------------------------------------------------------------------------
212 // Non-product mode code
213 #ifndef PRODUCT
214
215 void CompiledDirectStaticCall::verify() {
216 // Verify call.
217 _call->verify();
218 if (os::is_MP()) {
219 _call->verify_alignment();
220 }
221
222 // Verify stub.
223 address stub = find_stub(/*is_aot*/ false);
224 assert(stub != NULL, "no stub found for static call");
225 // Creation also verifies the object.
226 NativeMovConstReg* method_holder = nativeMovConstReg_at(stub + IC_pos_in_java_to_interp_stub);
227 NativeJump* jump = nativeJump_at(method_holder->next_instruction_address());
228
229 // Verify state.
230 assert(is_clean() || is_call_to_compiled() || is_call_to_interpreted(), "sanity check");
231 }
232
233 #endif // !PRODUCT