1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef ART_COMPILER_DEBUG_ELF_GNU_DEBUGDATA_WRITER_H_
18 #define ART_COMPILER_DEBUG_ELF_GNU_DEBUGDATA_WRITER_H_
19 
20 #include <vector>
21 
22 #include "arch/instruction_set.h"
23 #include "elf_builder.h"
24 #include "linker/vector_output_stream.h"
25 
26 // liblzma.
27 #include "7zCrc.h"
28 #include "XzCrc64.h"
29 #include "XzEnc.h"
30 
31 namespace art {
32 namespace debug {
33 
XzCompress(const std::vector<uint8_t> * src,std::vector<uint8_t> * dst)34 static void XzCompress(const std::vector<uint8_t>* src, std::vector<uint8_t>* dst) {
35   // Configure the compression library.
36   CrcGenerateTable();
37   Crc64GenerateTable();
38   CLzma2EncProps lzma2Props;
39   Lzma2EncProps_Init(&lzma2Props);
40   lzma2Props.lzmaProps.level = 1;  // Fast compression.
41   Lzma2EncProps_Normalize(&lzma2Props);
42   CXzProps props;
43   XzProps_Init(&props);
44   props.lzma2Props = &lzma2Props;
45   // Implement the required interface for communication (written in C so no virtual methods).
46   struct XzCallbacks : public ISeqInStream, public ISeqOutStream, public ICompressProgress {
47     static SRes ReadImpl(void* p, void* buf, size_t* size) {
48       auto* ctx = static_cast<XzCallbacks*>(reinterpret_cast<ISeqInStream*>(p));
49       *size = std::min(*size, ctx->src_->size() - ctx->src_pos_);
50       memcpy(buf, ctx->src_->data() + ctx->src_pos_, *size);
51       ctx->src_pos_ += *size;
52       return SZ_OK;
53     }
54     static size_t WriteImpl(void* p, const void* buf, size_t size) {
55       auto* ctx = static_cast<XzCallbacks*>(reinterpret_cast<ISeqOutStream*>(p));
56       const uint8_t* buffer = reinterpret_cast<const uint8_t*>(buf);
57       ctx->dst_->insert(ctx->dst_->end(), buffer, buffer + size);
58       return size;
59     }
60     static SRes ProgressImpl(void* , UInt64, UInt64) {
61       return SZ_OK;
62     }
63     size_t src_pos_;
64     const std::vector<uint8_t>* src_;
65     std::vector<uint8_t>* dst_;
66   };
67   XzCallbacks callbacks;
68   callbacks.Read = XzCallbacks::ReadImpl;
69   callbacks.Write = XzCallbacks::WriteImpl;
70   callbacks.Progress = XzCallbacks::ProgressImpl;
71   callbacks.src_pos_ = 0;
72   callbacks.src_ = src;
73   callbacks.dst_ = dst;
74   // Compress.
75   SRes res = Xz_Encode(&callbacks, &callbacks, &props, &callbacks);
76   CHECK_EQ(res, SZ_OK);
77 }
78 
79 template <typename ElfTypes>
MakeMiniDebugInfoInternal(InstructionSet isa,const InstructionSetFeatures * features,size_t rodata_section_size,size_t text_section_size,const ArrayRef<const MethodDebugInfo> & method_infos)80 static std::vector<uint8_t> MakeMiniDebugInfoInternal(
81     InstructionSet isa,
82     const InstructionSetFeatures* features,
83     size_t rodata_section_size,
84     size_t text_section_size,
85     const ArrayRef<const MethodDebugInfo>& method_infos) {
86   std::vector<uint8_t> buffer;
87   buffer.reserve(KB);
88   VectorOutputStream out("Mini-debug-info ELF file", &buffer);
89   std::unique_ptr<ElfBuilder<ElfTypes>> builder(new ElfBuilder<ElfTypes>(isa, features, &out));
90   builder->Start();
91   // Mirror .rodata and .text as NOBITS sections.
92   // It is needed to detected relocations after compression.
93   builder->GetRoData()->WriteNoBitsSection(rodata_section_size);
94   builder->GetText()->WriteNoBitsSection(text_section_size);
95   WriteDebugSymbols(builder.get(), method_infos, false /* with_signature */);
96   WriteCFISection(builder.get(),
97                   method_infos,
98                   dwarf::DW_DEBUG_FRAME_FORMAT,
99                   false /* write_oat_paches */);
100   builder->End();
101   CHECK(builder->Good());
102   std::vector<uint8_t> compressed_buffer;
103   compressed_buffer.reserve(buffer.size() / 4);
104   XzCompress(&buffer, &compressed_buffer);
105   return compressed_buffer;
106 }
107 
108 }  // namespace debug
109 }  // namespace art
110 
111 #endif  // ART_COMPILER_DEBUG_ELF_GNU_DEBUGDATA_WRITER_H_
112 
113