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      1 // Copyright 2011 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "src/disassembler.h"
      6 
      7 #include "src/code-stubs.h"
      8 #include "src/codegen.h"
      9 #include "src/debug/debug.h"
     10 #include "src/deoptimizer.h"
     11 #include "src/disasm.h"
     12 #include "src/macro-assembler.h"
     13 #include "src/snapshot/serialize.h"
     14 #include "src/string-stream.h"
     15 
     16 namespace v8 {
     17 namespace internal {
     18 
     19 #ifdef ENABLE_DISASSEMBLER
     20 
     21 class V8NameConverter: public disasm::NameConverter {
     22  public:
     23   explicit V8NameConverter(Code* code) : code_(code) {}
     24   virtual const char* NameOfAddress(byte* pc) const;
     25   virtual const char* NameInCode(byte* addr) const;
     26   Code* code() const { return code_; }
     27  private:
     28   Code* code_;
     29 
     30   EmbeddedVector<char, 128> v8_buffer_;
     31 };
     32 
     33 
     34 const char* V8NameConverter::NameOfAddress(byte* pc) const {
     35   const char* name =
     36       code_ == NULL ? NULL : code_->GetIsolate()->builtins()->Lookup(pc);
     37 
     38   if (name != NULL) {
     39     SNPrintF(v8_buffer_, "%s  (%p)", name, pc);
     40     return v8_buffer_.start();
     41   }
     42 
     43   if (code_ != NULL) {
     44     int offs = static_cast<int>(pc - code_->instruction_start());
     45     // print as code offset, if it seems reasonable
     46     if (0 <= offs && offs < code_->instruction_size()) {
     47       SNPrintF(v8_buffer_, "%d  (%p)", offs, pc);
     48       return v8_buffer_.start();
     49     }
     50   }
     51 
     52   return disasm::NameConverter::NameOfAddress(pc);
     53 }
     54 
     55 
     56 const char* V8NameConverter::NameInCode(byte* addr) const {
     57   // The V8NameConverter is used for well known code, so we can "safely"
     58   // dereference pointers in generated code.
     59   return (code_ != NULL) ? reinterpret_cast<const char*>(addr) : "";
     60 }
     61 
     62 
     63 static void DumpBuffer(std::ostream* os, StringBuilder* out) {
     64   (*os) << out->Finalize() << std::endl;
     65   out->Reset();
     66 }
     67 
     68 
     69 static const int kOutBufferSize = 2048 + String::kMaxShortPrintLength;
     70 static const int kRelocInfoPosition = 57;
     71 
     72 static int DecodeIt(Isolate* isolate, std::ostream* os,
     73                     const V8NameConverter& converter, byte* begin, byte* end) {
     74   SealHandleScope shs(isolate);
     75   DisallowHeapAllocation no_alloc;
     76   ExternalReferenceEncoder ref_encoder(isolate);
     77 
     78   v8::internal::EmbeddedVector<char, 128> decode_buffer;
     79   v8::internal::EmbeddedVector<char, kOutBufferSize> out_buffer;
     80   StringBuilder out(out_buffer.start(), out_buffer.length());
     81   byte* pc = begin;
     82   disasm::Disassembler d(converter);
     83   RelocIterator* it = NULL;
     84   if (converter.code() != NULL) {
     85     it = new RelocIterator(converter.code());
     86   } else {
     87     // No relocation information when printing code stubs.
     88   }
     89   int constants = -1;  // no constants being decoded at the start
     90 
     91   while (pc < end) {
     92     // First decode instruction so that we know its length.
     93     byte* prev_pc = pc;
     94     if (constants > 0) {
     95       SNPrintF(decode_buffer,
     96                "%08x       constant",
     97                *reinterpret_cast<int32_t*>(pc));
     98       constants--;
     99       pc += 4;
    100     } else {
    101       int num_const = d.ConstantPoolSizeAt(pc);
    102       if (num_const >= 0) {
    103         SNPrintF(decode_buffer,
    104                  "%08x       constant pool begin (num_const = %d)",
    105                  *reinterpret_cast<int32_t*>(pc), num_const);
    106         constants = num_const;
    107         pc += 4;
    108       } else if (it != NULL && !it->done() && it->rinfo()->pc() == pc &&
    109           it->rinfo()->rmode() == RelocInfo::INTERNAL_REFERENCE) {
    110         // raw pointer embedded in code stream, e.g., jump table
    111         byte* ptr = *reinterpret_cast<byte**>(pc);
    112         SNPrintF(decode_buffer,
    113                  "%08" V8PRIxPTR "      jump table entry %4" V8PRIdPTR,
    114                  reinterpret_cast<intptr_t>(ptr),
    115                  ptr - begin);
    116         pc += sizeof(ptr);
    117       } else {
    118         decode_buffer[0] = '\0';
    119         pc += d.InstructionDecode(decode_buffer, pc);
    120       }
    121     }
    122 
    123     // Collect RelocInfo for this instruction (prev_pc .. pc-1)
    124     List<const char*> comments(4);
    125     List<byte*> pcs(1);
    126     List<RelocInfo::Mode> rmodes(1);
    127     List<intptr_t> datas(1);
    128     if (it != NULL) {
    129       while (!it->done() && it->rinfo()->pc() < pc) {
    130         if (RelocInfo::IsComment(it->rinfo()->rmode())) {
    131           // For comments just collect the text.
    132           comments.Add(reinterpret_cast<const char*>(it->rinfo()->data()));
    133         } else {
    134           // For other reloc info collect all data.
    135           pcs.Add(it->rinfo()->pc());
    136           rmodes.Add(it->rinfo()->rmode());
    137           datas.Add(it->rinfo()->data());
    138         }
    139         it->next();
    140       }
    141     }
    142 
    143     // Comments.
    144     for (int i = 0; i < comments.length(); i++) {
    145       out.AddFormatted("                  %s", comments[i]);
    146       DumpBuffer(os, &out);
    147     }
    148 
    149     // Instruction address and instruction offset.
    150     out.AddFormatted("%p  %4d  ", prev_pc, prev_pc - begin);
    151 
    152     // Instruction.
    153     out.AddFormatted("%s", decode_buffer.start());
    154 
    155     // Print all the reloc info for this instruction which are not comments.
    156     for (int i = 0; i < pcs.length(); i++) {
    157       // Put together the reloc info
    158       RelocInfo relocinfo(isolate, pcs[i], rmodes[i], datas[i],
    159                           converter.code());
    160 
    161       // Indent the printing of the reloc info.
    162       if (i == 0) {
    163         // The first reloc info is printed after the disassembled instruction.
    164         out.AddPadding(' ', kRelocInfoPosition - out.position());
    165       } else {
    166         // Additional reloc infos are printed on separate lines.
    167         DumpBuffer(os, &out);
    168         out.AddPadding(' ', kRelocInfoPosition);
    169       }
    170 
    171       RelocInfo::Mode rmode = relocinfo.rmode();
    172       if (RelocInfo::IsPosition(rmode)) {
    173         if (RelocInfo::IsStatementPosition(rmode)) {
    174           out.AddFormatted("    ;; debug: statement %d", relocinfo.data());
    175         } else {
    176           out.AddFormatted("    ;; debug: position %d", relocinfo.data());
    177         }
    178       } else if (rmode == RelocInfo::DEOPT_REASON) {
    179         Deoptimizer::DeoptReason reason =
    180             static_cast<Deoptimizer::DeoptReason>(relocinfo.data());
    181         out.AddFormatted("    ;; debug: deopt reason '%s'",
    182                          Deoptimizer::GetDeoptReason(reason));
    183       } else if (rmode == RelocInfo::EMBEDDED_OBJECT) {
    184         HeapStringAllocator allocator;
    185         StringStream accumulator(&allocator);
    186         relocinfo.target_object()->ShortPrint(&accumulator);
    187         base::SmartArrayPointer<const char> obj_name = accumulator.ToCString();
    188         out.AddFormatted("    ;; object: %s", obj_name.get());
    189       } else if (rmode == RelocInfo::EXTERNAL_REFERENCE) {
    190         const char* reference_name = ref_encoder.NameOfAddress(
    191             isolate, relocinfo.target_external_reference());
    192         out.AddFormatted("    ;; external reference (%s)", reference_name);
    193       } else if (RelocInfo::IsCodeTarget(rmode)) {
    194         out.AddFormatted("    ;; code:");
    195         Code* code = Code::GetCodeFromTargetAddress(relocinfo.target_address());
    196         Code::Kind kind = code->kind();
    197         if (code->is_inline_cache_stub()) {
    198           if (kind == Code::LOAD_IC &&
    199               LoadICState::GetTypeofMode(code->extra_ic_state()) ==
    200                   NOT_INSIDE_TYPEOF) {
    201             out.AddFormatted(" contextual,");
    202           }
    203           InlineCacheState ic_state = code->ic_state();
    204           out.AddFormatted(" %s, %s", Code::Kind2String(kind),
    205               Code::ICState2String(ic_state));
    206           if (ic_state == MONOMORPHIC) {
    207             Code::StubType type = code->type();
    208             out.AddFormatted(", %s", Code::StubType2String(type));
    209           }
    210         } else if (kind == Code::STUB || kind == Code::HANDLER) {
    211           // Get the STUB key and extract major and minor key.
    212           uint32_t key = code->stub_key();
    213           uint32_t minor_key = CodeStub::MinorKeyFromKey(key);
    214           CodeStub::Major major_key = CodeStub::GetMajorKey(code);
    215           DCHECK(major_key == CodeStub::MajorKeyFromKey(key));
    216           out.AddFormatted(" %s, %s, ", Code::Kind2String(kind),
    217                            CodeStub::MajorName(major_key));
    218           out.AddFormatted("minor: %d", minor_key);
    219         } else {
    220           out.AddFormatted(" %s", Code::Kind2String(kind));
    221         }
    222         if (rmode == RelocInfo::CODE_TARGET_WITH_ID) {
    223           out.AddFormatted(" (id = %d)", static_cast<int>(relocinfo.data()));
    224         }
    225       } else if (RelocInfo::IsRuntimeEntry(rmode) &&
    226                  isolate->deoptimizer_data() != NULL) {
    227         // A runtime entry reloinfo might be a deoptimization bailout.
    228         Address addr = relocinfo.target_address();
    229         int id = Deoptimizer::GetDeoptimizationId(isolate,
    230                                                   addr,
    231                                                   Deoptimizer::EAGER);
    232         if (id == Deoptimizer::kNotDeoptimizationEntry) {
    233           id = Deoptimizer::GetDeoptimizationId(isolate,
    234                                                 addr,
    235                                                 Deoptimizer::LAZY);
    236           if (id == Deoptimizer::kNotDeoptimizationEntry) {
    237             id = Deoptimizer::GetDeoptimizationId(isolate,
    238                                                   addr,
    239                                                   Deoptimizer::SOFT);
    240             if (id == Deoptimizer::kNotDeoptimizationEntry) {
    241               out.AddFormatted("    ;; %s", RelocInfo::RelocModeName(rmode));
    242             } else {
    243               out.AddFormatted("    ;; soft deoptimization bailout %d", id);
    244             }
    245           } else {
    246             out.AddFormatted("    ;; lazy deoptimization bailout %d", id);
    247           }
    248         } else {
    249           out.AddFormatted("    ;; deoptimization bailout %d", id);
    250         }
    251       } else {
    252         out.AddFormatted("    ;; %s", RelocInfo::RelocModeName(rmode));
    253       }
    254     }
    255     DumpBuffer(os, &out);
    256   }
    257 
    258   // Emit comments following the last instruction (if any).
    259   if (it != NULL) {
    260     for ( ; !it->done(); it->next()) {
    261       if (RelocInfo::IsComment(it->rinfo()->rmode())) {
    262         out.AddFormatted("                  %s",
    263                          reinterpret_cast<const char*>(it->rinfo()->data()));
    264         DumpBuffer(os, &out);
    265       }
    266     }
    267   }
    268 
    269   delete it;
    270   return static_cast<int>(pc - begin);
    271 }
    272 
    273 
    274 int Disassembler::Decode(Isolate* isolate, std::ostream* os, byte* begin,
    275                          byte* end, Code* code) {
    276   V8NameConverter v8NameConverter(code);
    277   return DecodeIt(isolate, os, v8NameConverter, begin, end);
    278 }
    279 
    280 #else  // ENABLE_DISASSEMBLER
    281 
    282 int Disassembler::Decode(Isolate* isolate, std::ostream* os, byte* begin,
    283                          byte* end, Code* code) {
    284   return 0;
    285 }
    286 
    287 #endif  // ENABLE_DISASSEMBLER
    288 
    289 }  // namespace internal
    290 }  // namespace v8
    291