1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
// Copyright 2008 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "v8.h"
#if defined(V8_TARGET_ARCH_ARM)
#include "codegen-inl.h"
#include "jump-target-inl.h"
#include "register-allocator-inl.h"
#include "virtual-frame-inl.h"
namespace v8 {
namespace internal {
// -------------------------------------------------------------------------
// JumpTarget implementation.
#define __ ACCESS_MASM(cgen()->masm())
void JumpTarget::DoJump() {
ASSERT(cgen()->has_valid_frame());
// Live non-frame registers are not allowed at unconditional jumps
// because we have no way of invalidating the corresponding results
// which are still live in the C++ code.
ASSERT(cgen()->HasValidEntryRegisters());
if (entry_frame_set_) {
if (entry_label_.is_bound()) {
// If we already bound and generated code at the destination then it
// is too late to ask for less optimistic type assumptions.
ASSERT(entry_frame_.IsCompatibleWith(cgen()->frame()));
}
// There already a frame expectation at the target.
cgen()->frame()->MergeTo(&entry_frame_);
cgen()->DeleteFrame();
} else {
// Clone the current frame to use as the expected one at the target.
set_entry_frame(cgen()->frame());
// Zap the fall-through frame since the jump was unconditional.
RegisterFile empty;
cgen()->SetFrame(NULL, &empty);
}
if (entry_label_.is_bound()) {
// You can't jump backwards to an already bound label unless you admitted
// up front that this was a bidirectional jump target. Bidirectional jump
// targets will zap their type info when bound in case some later virtual
// frame with less precise type info branches to them.
ASSERT(direction_ != FORWARD_ONLY);
}
__ jmp(&entry_label_);
}
void JumpTarget::DoBranch(Condition cond, Hint ignored) {
ASSERT(cgen()->has_valid_frame());
if (entry_frame_set_) {
if (entry_label_.is_bound()) {
// If we already bound and generated code at the destination then it
// is too late to ask for less optimistic type assumptions.
ASSERT(entry_frame_.IsCompatibleWith(cgen()->frame()));
}
// We have an expected frame to merge to on the backward edge.
cgen()->frame()->MergeTo(&entry_frame_, cond);
} else {
// Clone the current frame to use as the expected one at the target.
set_entry_frame(cgen()->frame());
}
if (entry_label_.is_bound()) {
// You can't branch backwards to an already bound label unless you admitted
// up front that this was a bidirectional jump target. Bidirectional jump
// targets will zap their type info when bound in case some later virtual
// frame with less precise type info branches to them.
ASSERT(direction_ != FORWARD_ONLY);
}
__ b(cond, &entry_label_);
if (cond == al) {
cgen()->DeleteFrame();
}
}
void JumpTarget::Call() {
// Call is used to push the address of the catch block on the stack as
// a return address when compiling try/catch and try/finally. We
// fully spill the frame before making the call. The expected frame
// at the label (which should be the only one) is the spilled current
// frame plus an in-memory return address. The "fall-through" frame
// at the return site is the spilled current frame.
ASSERT(cgen()->has_valid_frame());
// There are no non-frame references across the call.
ASSERT(cgen()->HasValidEntryRegisters());
ASSERT(!is_linked());
// Calls are always 'forward' so we use a copy of the current frame (plus
// one for a return address) as the expected frame.
ASSERT(!entry_frame_set_);
VirtualFrame target_frame = *cgen()->frame();
target_frame.Adjust(1);
set_entry_frame(&target_frame);
__ bl(&entry_label_);
}
void JumpTarget::DoBind() {
ASSERT(!is_bound());
// Live non-frame registers are not allowed at the start of a basic
// block.
ASSERT(!cgen()->has_valid_frame() || cgen()->HasValidEntryRegisters());
if (cgen()->has_valid_frame()) {
if (direction_ != FORWARD_ONLY) cgen()->frame()->ForgetTypeInfo();
// If there is a current frame we can use it on the fall through.
if (!entry_frame_set_) {
entry_frame_ = *cgen()->frame();
entry_frame_set_ = true;
} else {
cgen()->frame()->MergeTo(&entry_frame_);
// On fall through we may have to merge both ways.
if (direction_ != FORWARD_ONLY) {
// This will not need to adjust the virtual frame entries that are
// register allocated since that was done above and they now match.
// But it does need to adjust the entry_frame_ of this jump target
// to make it potentially less optimistic. Later code can branch back
// to this jump target and we need to assert that that code does not
// have weaker assumptions about types.
entry_frame_.MergeTo(cgen()->frame());
}
}
} else {
// If there is no current frame we must have an entry frame which we can
// copy.
ASSERT(entry_frame_set_);
RegisterFile empty;
cgen()->SetFrame(new VirtualFrame(&entry_frame_), &empty);
}
__ bind(&entry_label_);
}
#undef __
} } // namespace v8::internal
#endif // V8_TARGET_ARCH_ARM
|
