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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