1 // Copyright 2014, ARM Limited
2 // All rights reserved.
3 //
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions are met:
6 //
7 // * Redistributions of source code must retain the above copyright notice,
8 // this list of conditions and the following disclaimer.
9 // * Redistributions in binary form must reproduce the above copyright notice,
10 // this list of conditions and the following disclaimer in the documentation
11 // and/or other materials provided with the distribution.
12 // * Neither the name of ARM Limited nor the names of its contributors may be
13 // used to endorse or promote products derived from this software without
14 // specific prior written permission.
15 //
16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
17 // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18 // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19 // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
20 // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22 // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
23 // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26
27 #include "vixl/code-buffer.h"
28 #include "vixl/utils.h"
29
30 namespace vixl {
31
32
CodeBuffer(size_t capacity)33 CodeBuffer::CodeBuffer(size_t capacity) : managed_(true), capacity_(capacity) {
34 VIXL_CHECK(capacity_ != 0);
35 buffer_ = reinterpret_cast<byte*>(malloc(capacity_));
36 VIXL_CHECK(buffer_ != NULL);
37 // A64 instructions must be word aligned, we assert the default allocator
38 // always returns word align memory.
39 VIXL_ASSERT(IsWordAligned(buffer_));
40
41 cursor_ = buffer_;
42 dirty_ = false;
43 }
44
45
CodeBuffer(void * buffer,size_t capacity)46 CodeBuffer::CodeBuffer(void* buffer, size_t capacity)
47 : buffer_(reinterpret_cast<byte*>(buffer)),
48 managed_(false),
49 cursor_(reinterpret_cast<byte*>(buffer)),
50 dirty_(false),
51 capacity_(capacity) {
52 VIXL_ASSERT(buffer_ != NULL);
53 }
54
55
~CodeBuffer()56 CodeBuffer::~CodeBuffer() {
57 VIXL_ASSERT(!IsDirty());
58 if (managed_) {
59 free(buffer_);
60 }
61 }
62
63
EmitString(const char * string)64 void CodeBuffer::EmitString(const char* string) {
65 VIXL_ASSERT(RemainingBytes() > strlen(string));
66 char* dst = reinterpret_cast<char*>(cursor_);
67 dirty_ = true;
68 char* null_char = stpcpy(dst, string);
69 cursor_ = reinterpret_cast<byte*>(null_char) + 1;
70 }
71
72
Align()73 void CodeBuffer::Align() {
74 byte* end = AlignUp(cursor_, 4);
75 VIXL_ASSERT(end >= cursor_);
76 const size_t padding_size = end - cursor_;
77 VIXL_ASSERT(RemainingBytes() >= padding_size);
78 VIXL_ASSERT(padding_size <= 4);
79 const byte padding[] = { 0, 0, 0, 0};
80 dirty_ = true;
81 memcpy(cursor_, padding, padding_size);
82 cursor_ = end;
83 }
84
85
Reset()86 void CodeBuffer::Reset() {
87 #ifdef VIXL_DEBUG
88 if (managed_) {
89 // TODO(all): Consider allowing for custom default values, e.g. HLT.
90 memset(buffer_, 0, capacity_);
91 }
92 #endif
93 cursor_ = buffer_;
94 SetClean();
95 }
96
97
Grow(size_t new_capacity)98 void CodeBuffer::Grow(size_t new_capacity) {
99 VIXL_ASSERT(managed_);
100 VIXL_ASSERT(new_capacity > capacity_);
101 size_t size = CursorOffset();
102 buffer_ = static_cast<byte*>(realloc(buffer_, new_capacity));
103 VIXL_CHECK(buffer_ != NULL);
104
105 cursor_ = buffer_ + size;
106 capacity_ = new_capacity;
107 }
108
109
110 } // namespace vixl
111