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v8/tools/wasm/module-inspector.cc
Jakob Kummerow d43969ea68 [tools][wasm] wami: Support hexdump for invalid modules 
When trying to understand why a given module fails to validate, it
can be helpful to disassemble it as far as possible until reaching
the erroneous byte(s).

Change-Id: I0056ba1a81b85a486c0446d15bbf54ccb2e8332e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3827866
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82433}
2022-08-12 10:50:08 +00:00

1233 lines
41 KiB
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// Copyright 2022 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <fstream>
#include <iomanip>
#include <iostream>
#include <vector>
#include "include/libplatform/libplatform.h"
#include "include/v8-initialization.h"
#include "src/wasm/function-body-decoder-impl.h"
#include "src/wasm/module-decoder-impl.h"
#include "src/wasm/names-provider.h"
#include "src/wasm/string-builder-multiline.h"
#include "src/wasm/wasm-disassembler-impl.h"
#include "src/wasm/wasm-opcodes-inl.h"
#if V8_OS_POSIX
#include <unistd.h>
#endif
int PrintHelp(char** argv) {
std::cerr << "Usage: Specify an action and a module in any order.\n"
<< "The action can be any of:\n"
<< " --help\n"
<< " Print this help and exit.\n"
<< " --list-functions\n"
<< " List functions in the given module\n"
<< " --section-stats\n"
<< " Show information about sections in the given module\n"
<< " --instruction-stats\n"
<< " Show information about instructions in the given module\n"
<< " --single-wat FUNC_INDEX\n"
<< " Print function FUNC_INDEX in .wat format\n"
<< " --full-wat\n"
<< " Print full module in .wat format\n"
<< " --single-hexdump FUNC_INDEX\n"
<< " Print function FUNC_INDEX in annotated hex format\n"
<< " --full-hexdump\n"
<< " Print full module in annotated hex format\n"
<< " --strip\n"
<< " Dump the module, in binary format, without its Name"
<< " section (requires using -o as well)\n"
<< "\n"
<< " -o OUTFILE or --output OUTFILE\n"
<< " Send output to OUTFILE instead of <stdout>\n";
return 1;
}
namespace v8 {
namespace internal {
namespace wasm {
enum class OutputMode { kWat, kHexDump };
static constexpr char kHexChars[] = "0123456789abcdef";
char* PrintHexBytesCore(char* ptr, uint32_t num_bytes, const byte* start) {
for (uint32_t i = 0; i < num_bytes; i++) {
byte b = *(start + i);
*(ptr++) = '0';
*(ptr++) = 'x';
*(ptr++) = kHexChars[b >> 4];
*(ptr++) = kHexChars[b & 0xF];
*(ptr++) = ',';
*(ptr++) = ' ';
}
return ptr;
}
// Computes the number of decimal digits required to print {value}.
int GetNumDigits(uint32_t value) {
int digits = 1;
for (uint32_t compare = 10; value >= compare; compare *= 10) digits++;
return digits;
}
class InstructionStatistics {
public:
void Record(WasmOpcode opcode, uint32_t size) {
Entry& entry = entries[opcode];
entry.opcode = opcode;
entry.count++;
entry.total_size += size;
}
void RecordImmediate(WasmOpcode opcode, int imm_value) {
OpcodeImmediates& map = immediates[opcode];
map[imm_value]++;
}
void RecordCodeSize(size_t chunk) { total_code_size_ += chunk; }
void RecordLocals(uint32_t count, uint32_t size) {
locals_count_ += count;
locals_size_ += size;
}
void WriteTo(std::ostream& out) {
// Sort by number of occurrences.
std::vector<Entry> sorted;
sorted.reserve(entries.size());
for (const auto& e : entries) sorted.push_back(e.second);
std::sort(sorted.begin(), sorted.end(),
[](const Entry& a, const Entry& b) { return a.count > b.count; });
// Prepare column widths.
int longest_mnemo = 0;
for (const Entry& e : sorted) {
int s = static_cast<int>(strlen(WasmOpcodes::OpcodeName(e.opcode)));
if (s > longest_mnemo) longest_mnemo = s;
}
constexpr int kSpacing = 2;
longest_mnemo =
std::max(longest_mnemo, static_cast<int>(strlen("Instruction"))) +
kSpacing;
uint32_t highest_count = sorted[0].count;
int count_digits = GetNumDigits(highest_count);
count_digits = std::max(count_digits, static_cast<int>(strlen("count")));
// Print headline.
out << std::setw(longest_mnemo) << std::left << "Instruction";
out << std::setw(count_digits) << std::right << "count";
out << std::setw(kSpacing) << " ";
out << std::setw(8) << "tot.size";
out << std::setw(kSpacing) << " ";
out << std::setw(8) << "avg.size";
out << std::setw(kSpacing) << " ";
out << std::setw(8) << "% of code\n";
// Print instruction counts.
auto PrintLine = [&](const char* name, uint32_t count,
uint32_t total_size) {
out << std::setw(longest_mnemo) << std::left << name;
out << std::setw(count_digits) << std::right << count;
out << std::setw(kSpacing) << " ";
out << std::setw(8) << total_size;
out << std::setw(kSpacing) << " ";
out << std::fixed << std::setprecision(2) << std::setw(8)
<< static_cast<double>(total_size) / count;
out << std::setw(kSpacing) << " ";
out << std::fixed << std::setprecision(1) << std::setw(8)
<< 100.0 * total_size / this->total_code_size_ << "%\n";
};
for (const Entry& e : sorted) {
PrintLine(WasmOpcodes::OpcodeName(e.opcode), e.count, e.total_size);
}
out << "\n";
PrintLine("locals", locals_count_, locals_size_);
// Print most common immediate values.
for (const auto& imm : immediates) {
WasmOpcode opcode = imm.first;
out << "\nMost common immediates for " << WasmOpcodes::OpcodeName(opcode)
<< ":\n";
std::vector<std::pair<int, int>> counts;
counts.reserve(imm.second.size());
for (const auto& pair : imm.second) {
counts.push_back(std::make_pair(pair.first, pair.second));
}
std::sort(counts.begin(), counts.end(),
[](const std::pair<int, uint32_t>& a,
const std::pair<int, uint32_t>& b) {
return a.second > b.second;
});
constexpr int kImmLen = 9; // Length of "Immediate".
int count_len = std::max(GetNumDigits(counts[0].second),
static_cast<int>(strlen("count")));
// How many most-common values to show.
size_t print_top = std::min(size_t{10}, counts.size());
out << std::setw(kImmLen) << "Immediate";
out << std::setw(kSpacing) << " ";
out << std::setw(count_len) << "count"
<< "\n";
for (size_t i = 0; i < print_top; i++) {
out << std::setw(kImmLen) << counts[i].first;
out << std::setw(kSpacing) << " ";
out << std::setw(count_len) << counts[i].second << "\n";
}
}
}
private:
struct Entry {
WasmOpcode opcode;
uint32_t count = 0;
uint32_t total_size = 0;
};
// First: immediate value, second: count.
using OpcodeImmediates = std::map<int, uint32_t>;
std::unordered_map<WasmOpcode, Entry> entries;
std::map<WasmOpcode, OpcodeImmediates> immediates;
size_t total_code_size_ = 0;
uint32_t locals_count_ = 0;
uint32_t locals_size_ = 0;
};
// A variant of FunctionBodyDisassembler that can produce "annotated hex dump"
// format, e.g.:
// 0xfb, 0x07, 0x01, // struct.new $type1
class ExtendedFunctionDis : public FunctionBodyDisassembler {
public:
ExtendedFunctionDis(Zone* zone, const WasmModule* module, uint32_t func_index,
WasmFeatures* detected, const FunctionSig* sig,
const byte* start, const byte* end, uint32_t offset,
NamesProvider* names)
: FunctionBodyDisassembler(zone, module, func_index, detected, sig, start,
end, offset, names) {}
static constexpr uint32_t kWeDontCareAboutByteCodeOffsetsHere = 0;
void HexDump(MultiLineStringBuilder& out, FunctionHeader include_header) {
out_ = &out;
if (!more()) return; // Fuzzers...
// Print header.
if (include_header == kPrintHeader) {
out << " // func ";
names_->PrintFunctionName(out, func_index_, NamesProvider::kDevTools);
PrintSignatureOneLine(out, sig_, func_index_, names_, true,
NamesProvider::kIndexAsComment);
out.NextLine(kWeDontCareAboutByteCodeOffsetsHere);
}
// Decode and print locals.
uint32_t locals_length;
InitializeLocalsFromSig();
DecodeLocals(pc_, &locals_length);
if (failed()) {
// TODO(jkummerow): Better error handling.
out << "Failed to decode locals";
return;
}
uint32_t total_length = 0;
uint32_t length;
uint32_t entries = read_u32v<validate>(pc_, &length);
PrintHexBytes(out, length, pc_, 4);
out << " // " << entries << " entries in locals list";
out.NextLine(kWeDontCareAboutByteCodeOffsetsHere);
total_length += length;
while (entries-- > 0) {
uint32_t count_length;
uint32_t count = read_u32v<validate>(pc_ + total_length, &count_length);
uint32_t type_length;
ValueType type = value_type_reader::read_value_type<validate>(
this, pc_ + total_length + count_length, &type_length, nullptr,
WasmFeatures::All());
PrintHexBytes(out, count_length + type_length, pc_ + total_length, 4);
out << " // " << count << (count != 1 ? " locals" : " local")
<< " of type ";
names_->PrintValueType(out, type);
out.NextLine(kWeDontCareAboutByteCodeOffsetsHere);
total_length += count_length + type_length;
}
consume_bytes(locals_length);
// Main loop.
while (pc_ < end_) {
WasmOpcode opcode = GetOpcode();
current_opcode_ = opcode; // Some immediates need to know this.
StringBuilder immediates;
uint32_t length = PrintImmediatesAndGetLength(immediates);
PrintHexBytes(out, length, pc_, 4);
if (opcode == kExprEnd) {
out << " // end";
if (label_stack_.size() > 0) {
const LabelInfo& label = label_stack_.back();
if (label.start != nullptr) {
out << " ";
out.write(label.start, label.length);
}
label_stack_.pop_back();
}
} else {
out << " // " << WasmOpcodes::OpcodeName(opcode);
}
out.write(immediates.start(), immediates.length());
if (opcode == kExprBlock || opcode == kExprIf || opcode == kExprLoop ||
opcode == kExprTry) {
label_stack_.emplace_back(out.line_number(), out.length(),
label_occurrence_index_++);
}
out.NextLine(kWeDontCareAboutByteCodeOffsetsHere);
pc_ += length;
}
if (pc_ != end_) {
// TODO(jkummerow): Better error handling.
out << "Beyond end of code\n";
}
}
void HexdumpConstantExpression(MultiLineStringBuilder& out) {
while (pc_ < end_) {
WasmOpcode opcode = GetOpcode();
current_opcode_ = opcode; // Some immediates need to know this.
StringBuilder immediates;
uint32_t length = PrintImmediatesAndGetLength(immediates);
// Don't print the final "end" separately.
if (pc_ + length + 1 == end_ && *(pc_ + length) == kExprEnd) {
length++;
}
PrintHexBytes(out, length, pc_, 4);
out << " // " << WasmOpcodes::OpcodeName(opcode);
out.write(immediates.start(), immediates.length());
out.NextLine(kWeDontCareAboutByteCodeOffsetsHere);
pc_ += length;
}
}
void PrintHexBytes(StringBuilder& out, uint32_t num_bytes, const byte* start,
uint32_t fill_to_minimum = 0) {
constexpr int kCharsPerByte = 6; // Length of "0xFF, ".
uint32_t max = std::max(num_bytes, fill_to_minimum) * kCharsPerByte + 2;
char* ptr = out.allocate(max);
*(ptr++) = ' ';
*(ptr++) = ' ';
ptr = PrintHexBytesCore(ptr, num_bytes, start);
if (fill_to_minimum > num_bytes) {
memset(ptr, ' ', (fill_to_minimum - num_bytes) * kCharsPerByte);
}
}
void CollectInstructionStats(InstructionStatistics& stats) {
uint32_t locals_length;
DecodeLocals(pc_, &locals_length);
if (failed()) return;
stats.RecordLocals(num_locals(), locals_length);
consume_bytes(locals_length);
while (pc_ < end_) {
WasmOpcode opcode = GetOpcode();
if (opcode == kExprI32Const) {
ImmI32Immediate<Decoder::kNoValidation> imm(this, pc_ + 1);
stats.RecordImmediate(opcode, imm.value);
} else if (opcode == kExprLocalGet || opcode == kExprGlobalGet) {
IndexImmediate<Decoder::kNoValidation> imm(this, pc_ + 1, "");
stats.RecordImmediate(opcode, static_cast<int>(imm.index));
}
uint32_t length = WasmDecoder::OpcodeLength(this, pc_);
stats.Record(opcode, length);
pc_ += length;
}
}
};
// A variant of ModuleDisassembler that produces "annotated hex dump" format,
// e.g.:
// 0x01, 0x70, 0x00, // table count 1: funcref no maximum
class HexDumpModuleDis;
class DumpingModuleDecoder : public ModuleDecoderTemplate<HexDumpModuleDis> {
public:
DumpingModuleDecoder(const ModuleWireBytes wire_bytes,
HexDumpModuleDis* module_dis)
: ModuleDecoderTemplate<HexDumpModuleDis>(
WasmFeatures::All(), wire_bytes.start(), wire_bytes.end(),
kWasmOrigin, *module_dis) {}
void onFirstError() override {
// Pretend we've reached the end of the section, but contrary to the
// superclass implementation do so without moving {pc_}, so whatever
// bytes caused the failure can still be dumped correctly.
end_ = pc_;
}
};
class HexDumpModuleDis {
public:
HexDumpModuleDis(MultiLineStringBuilder& out, const WasmModule* module,
NamesProvider* names, const ModuleWireBytes wire_bytes,
AccountingAllocator* allocator)
: out_(out),
module_(module),
names_(names),
wire_bytes_(wire_bytes),
allocator_(allocator),
zone_(allocator, "disassembler") {}
// Public entrypoint.
void PrintModule() {
DumpingModuleDecoder decoder(wire_bytes_, this);
decoder_ = &decoder;
// If the module failed validation, create fakes to allow us to print
// what we can.
std::unique_ptr<WasmModule> fake_module;
std::unique_ptr<NamesProvider> names_provider;
if (!names_) {
fake_module.reset(
new WasmModule(std::make_unique<Zone>(allocator_, "fake module")));
names_provider.reset(
new NamesProvider(fake_module.get(), wire_bytes_.module_bytes()));
names_ = names_provider.get();
}
out_ << "[";
out_.NextLine(0);
constexpr bool verify_functions = false;
decoder.DecodeModule(nullptr, allocator_, verify_functions);
out_ << "]";
if (total_bytes_ != wire_bytes_.length()) {
std::cerr << "WARNING: OUTPUT INCOMPLETE. Disassembled " << total_bytes_
<< " out of " << wire_bytes_.length() << " bytes.\n";
}
// For cleanliness, reset {names_} if it's pointing at a fake.
if (names_ == names_provider.get()) {
names_ = nullptr;
}
}
// Tracer hooks.
void Bytes(const byte* start, uint32_t count) {
if (count > kMaxBytesPerLine) {
DCHECK_EQ(queue_, nullptr);
queue_ = start;
queue_length_ = count;
total_bytes_ += count;
return;
}
if (line_bytes_ == 0) out_ << " ";
PrintHexBytes(out_, count, start);
line_bytes_ += count;
total_bytes_ += count;
}
void Description(const char* desc) { description_ << desc; }
void Description(const char* desc, size_t length) {
description_.write(desc, length);
}
void Description(uint32_t number) {
if (description_.length() != 0) description_ << " ";
description_ << number;
}
void Description(ValueType type) {
if (description_.length() != 0) description_ << " ";
names_->PrintValueType(description_, type);
}
void Description(HeapType type) {
if (description_.length() != 0) description_ << " ";
names_->PrintHeapType(description_, type);
}
void Description(const FunctionSig* sig) {
PrintSignatureOneLine(description_, sig, 0 /* ignored */, names_, false);
}
void FunctionName(uint32_t func_index) {
description_ << func_index << " ";
names_->PrintFunctionName(description_, func_index,
NamesProvider::kDevTools);
}
void NextLineIfFull() {
if (queue_ || line_bytes_ >= kPadBytes) NextLine();
}
void NextLineIfNonEmpty() {
if (queue_ || line_bytes_ > 0) NextLine();
}
void NextLine() {
if (queue_) {
// Print queued hex bytes first, unless there have also been unqueued
// bytes.
if (line_bytes_ > 0) {
// Keep the queued bytes together on the next line.
for (; line_bytes_ < kPadBytes; line_bytes_++) {
out_ << " ";
}
out_ << " // ";
out_.write(description_.start(), description_.length());
out_.NextLine(kDontCareAboutOffsets);
}
while (queue_length_ > kMaxBytesPerLine) {
out_ << " ";
PrintHexBytes(out_, kMaxBytesPerLine, queue_);
out_.NextLine(kDontCareAboutOffsets);
queue_length_ -= kMaxBytesPerLine;
queue_ += kMaxBytesPerLine;
}
if (queue_length_ > 0) {
out_ << " ";
PrintHexBytes(out_, queue_length_, queue_);
}
if (line_bytes_ == 0) {
if (queue_length_ > kPadBytes) {
out_.NextLine(kDontCareAboutOffsets);
out_ << " // ";
} else {
for (uint32_t i = queue_length_; i < kPadBytes; i++) {
out_ << " ";
}
out_ << " // ";
}
out_.write(description_.start(), description_.length());
}
queue_ = nullptr;
} else {
// No queued bytes; just write the accumulated description.
if (description_.length() != 0) {
if (line_bytes_ == 0) out_ << " ";
for (; line_bytes_ < kPadBytes; line_bytes_++) {
out_ << " ";
}
out_ << " // ";
out_.write(description_.start(), description_.length());
}
}
out_.NextLine(kDontCareAboutOffsets);
line_bytes_ = 0;
description_.rewind_to_start();
}
// We don't care about offsets, but we can use these hooks to provide
// helpful indexing comments in long lists.
void TypeOffset(uint32_t offset) {
if (!module_ || module_->types.size() > 3) {
description_ << "type #" << next_type_index_ << " ";
names_->PrintTypeName(description_, next_type_index_);
next_type_index_++;
}
}
void ImportOffset(uint32_t offset) {
description_ << "import #" << next_import_index_++;
NextLine();
}
void ImportsDone() {
const WasmModule* module = decoder_->shared_module().get();
next_table_index_ = static_cast<uint32_t>(module->tables.size());
next_global_index_ = static_cast<uint32_t>(module->globals.size());
next_tag_index_ = static_cast<uint32_t>(module->tags.size());
}
void TableOffset(uint32_t offset) {
if (!module_ || module_->tables.size() > 3) {
description_ << "table #" << next_table_index_++;
}
}
void MemoryOffset(uint32_t offset) {}
void TagOffset(uint32_t offset) {
if (!module_ || module_->tags.size() > 3) {
description_ << "tag #" << next_tag_index_++ << ":";
}
}
void GlobalOffset(uint32_t offset) {
description_ << "global #" << next_global_index_++ << ":";
}
void StartOffset(uint32_t offset) {}
void ElementOffset(uint32_t offset) {
if (!module_ || module_->elem_segments.size() > 3) {
description_ << "segment #" << next_segment_index_++;
NextLine();
}
}
void DataOffset(uint32_t offset) {
if (!module_ || module_->data_segments.size() > 3) {
description_ << "data segment #" << next_data_segment_index_++;
NextLine();
}
}
// The following two hooks give us an opportunity to call the hex-dumping
// function body disassembler for initializers and functions.
void InitializerExpression(const byte* start, const byte* end,
ValueType expected_type) {
WasmFeatures detected;
auto sig = FixedSizeSignature<ValueType>::Returns(expected_type);
uint32_t offset = decoder_->pc_offset();
const WasmModule* module = module_;
if (!module) module = decoder_->shared_module().get();
ExtendedFunctionDis d(&zone_, module, 0, &detected, &sig, start, end,
offset, names_);
d.HexdumpConstantExpression(out_);
total_bytes_ += static_cast<size_t>(end - start);
}
void FunctionBody(const WasmFunction* func, const byte* start) {
const byte* end = start + func->code.length();
WasmFeatures detected;
uint32_t offset = static_cast<uint32_t>(start - decoder_->start());
const WasmModule* module = module_;
if (!module) module = decoder_->shared_module().get();
ExtendedFunctionDis d(&zone_, module, func->func_index, &detected,
func->sig, start, end, offset, names_);
d.HexDump(out_, FunctionBodyDisassembler::kSkipHeader);
total_bytes_ += func->code.length();
}
// We have to do extra work for the name section here, because the regular
// decoder mostly just skips over it.
void NameSection(const byte* start, const byte* end, uint32_t offset) {
Decoder decoder(start, end, offset);
while (decoder.ok() && decoder.more()) {
uint8_t name_type = decoder.consume_u8("name type: ", *this);
Description(NameTypeName(name_type));
NextLine();
uint32_t payload_length = decoder.consume_u32v("payload length:", *this);
Description(payload_length);
NextLine();
if (!decoder.checkAvailable(payload_length)) break;
switch (name_type) {
case kModuleCode:
consume_string(&decoder, unibrow::Utf8Variant::kLossyUtf8,
"module name", *this);
break;
case kFunctionCode:
case kTypeCode:
case kTableCode:
case kMemoryCode:
case kGlobalCode:
case kElementSegmentCode:
case kDataSegmentCode:
case kTagCode:
DumpNameMap(decoder);
break;
case kLocalCode:
case kLabelCode:
case kFieldCode:
DumpIndirectNameMap(decoder);
break;
default:
Bytes(decoder.pc(), payload_length);
NextLine();
decoder.consume_bytes(payload_length);
break;
}
}
}
private:
static constexpr uint32_t kDontCareAboutOffsets = 0;
static constexpr uint32_t kMaxBytesPerLine = 8;
static constexpr uint32_t kPadBytes = 4;
void PrintHexBytes(StringBuilder& out, uint32_t num_bytes,
const byte* start) {
char* ptr = out.allocate(num_bytes * 6);
PrintHexBytesCore(ptr, num_bytes, start);
}
void DumpNameMap(Decoder& decoder) {
uint32_t count = decoder.consume_u32v("names count", *this);
Description(count);
NextLine();
for (uint32_t i = 0; i < count; i++) {
uint32_t index = decoder.consume_u32v("index", *this);
Description(index);
Description(" ");
consume_string(&decoder, unibrow::Utf8Variant::kLossyUtf8, "name", *this);
if (!decoder.ok()) break;
}
}
void DumpIndirectNameMap(Decoder& decoder) {
uint32_t outer_count = decoder.consume_u32v("outer count", *this);
Description(outer_count);
NextLine();
for (uint32_t i = 0; i < outer_count; i++) {
uint32_t outer_index = decoder.consume_u32v("outer index", *this);
Description(outer_index);
uint32_t inner_count = decoder.consume_u32v(" inner count", *this);
Description(inner_count);
NextLine();
for (uint32_t j = 0; j < inner_count; j++) {
uint32_t inner_index = decoder.consume_u32v("inner index", *this);
Description(inner_index);
Description(" ");
consume_string(&decoder, unibrow::Utf8Variant::kLossyUtf8, "name",
*this);
if (!decoder.ok()) break;
}
if (!decoder.ok()) break;
}
}
static constexpr const char* NameTypeName(uint8_t name_type) {
switch (name_type) {
// clang-format off
case kModuleCode: return "module";
case kFunctionCode: return "function";
case kTypeCode: return "type";
case kTableCode: return "table";
case kMemoryCode: return "memory";
case kGlobalCode: return "global";
case kElementSegmentCode: return "element segment";
case kDataSegmentCode: return "data segment";
case kTagCode: return "tag";
case kLocalCode: return "local";
case kLabelCode: return "label";
case kFieldCode: return "field";
default: return "unknown";
// clang-format on
}
}
MultiLineStringBuilder& out_;
const WasmModule* module_;
NamesProvider* names_;
const ModuleWireBytes wire_bytes_;
AccountingAllocator* allocator_;
Zone zone_;
StringBuilder description_;
const byte* queue_{nullptr};
uint32_t queue_length_{0};
uint32_t line_bytes_{0};
size_t total_bytes_{0};
DumpingModuleDecoder* decoder_{nullptr};
uint32_t next_type_index_{0};
uint32_t next_import_index_{0};
uint32_t next_table_index_{0};
uint32_t next_global_index_{0};
uint32_t next_tag_index_{0};
uint32_t next_segment_index_{0};
uint32_t next_data_segment_index_{0};
};
////////////////////////////////////////////////////////////////////////////////
class FormatConverter {
public:
enum Status { kNotReady, kIoInitialized, kModuleReady };
explicit FormatConverter(const char* input, const char* output)
: output_(output), out_(output_.get()) {
if (!output_.ok()) return;
if (!LoadFile(input)) return;
base::Vector<const byte> wire_bytes(raw_bytes_.data(), raw_bytes_.size());
wire_bytes_ = ModuleWireBytes({raw_bytes_.data(), raw_bytes_.size()});
status_ = kIoInitialized;
ModuleResult result =
DecodeWasmModuleForDisassembler(start(), end(), &allocator_);
if (result.failed()) {
WasmError error = result.error();
std::cerr << "Decoding error: " << error.message() << " at offset "
<< error.offset() << "\n";
return;
}
status_ = kModuleReady;
module_ = result.value();
names_provider_ =
std::make_unique<NamesProvider>(module_.get(), wire_bytes);
}
Status status() const { return status_; }
void ListFunctions() {
DCHECK_EQ(status_, kModuleReady);
const WasmModule* m = module();
uint32_t num_functions = static_cast<uint32_t>(m->functions.size());
out_ << "There are " << num_functions << " functions ("
<< m->num_imported_functions << " imported, "
<< m->num_declared_functions
<< " locally defined); the following have names:\n";
for (uint32_t i = 0; i < num_functions; i++) {
StringBuilder sb;
names()->PrintFunctionName(sb, i);
if (sb.length() == 0) continue;
std::string name(sb.start(), sb.length());
out_ << i << " " << name << "\n";
}
}
void SectionStats() {
DCHECK_EQ(status_, kModuleReady);
Decoder decoder(start(), end());
decoder.consume_bytes(kModuleHeaderSize, "module header");
uint32_t module_size = static_cast<uint32_t>(end() - start());
int digits = GetNumDigits(module_size);
size_t kMinNameLength = 8;
// 18 = kMinNameLength + strlen(" section: ").
out_ << std::setw(18) << std::left << "Module size: ";
out_ << std::setw(digits) << std::right << module_size << " bytes\n";
NoTracer no_tracer;
for (WasmSectionIterator it(&decoder, no_tracer); it.more();
it.advance(true)) {
const char* name = SectionName(it.section_code());
size_t name_len = strlen(name);
out_ << SectionName(it.section_code()) << " section: ";
for (; name_len < kMinNameLength; name_len++) out_ << " ";
uint32_t length = it.section_length();
out_ << std::setw(name_len > kMinNameLength ? 0 : digits) << length
<< " bytes / ";
out_ << std::fixed << std::setprecision(1) << std::setw(4)
<< 100.0 * length / module_size;
out_ << "% of total\n";
}
}
void Strip() {
DCHECK_EQ(status_, kModuleReady);
Decoder decoder(start(), end());
out_.write(reinterpret_cast<const char*>(decoder.pc()), kModuleHeaderSize);
decoder.consume_bytes(kModuleHeaderSize);
NoTracer no_tracer;
for (WasmSectionIterator it(&decoder, no_tracer); it.more();
it.advance(true)) {
if (it.section_code() == kNameSectionCode) continue;
out_.write(reinterpret_cast<const char*>(it.section_start()),
it.section_length());
}
}
void InstructionStats() {
DCHECK_EQ(status_, kModuleReady);
Zone zone(&allocator_, "disassembler");
InstructionStatistics stats;
for (uint32_t i = module()->num_imported_functions;
i < module()->functions.size(); i++) {
const WasmFunction* func = &module()->functions[i];
WasmFeatures detected;
base::Vector<const byte> code = wire_bytes_.GetFunctionBytes(func);
ExtendedFunctionDis d(&zone, module(), i, &detected, func->sig,
code.begin(), code.end(), func->code.offset(),
names());
d.CollectInstructionStats(stats);
stats.RecordCodeSize(code.size());
}
stats.WriteTo(out_);
}
void DisassembleFunction(uint32_t func_index, OutputMode mode) {
DCHECK_EQ(status_, kModuleReady);
MultiLineStringBuilder sb;
if (func_index >= module()->functions.size()) {
sb << "Invalid function index!\n";
return;
}
if (func_index < module()->num_imported_functions) {
sb << "Can't disassemble imported functions!\n";
return;
}
const WasmFunction* func = &module()->functions[func_index];
Zone zone(&allocator_, "disassembler");
WasmFeatures detected;
base::Vector<const byte> code = wire_bytes_.GetFunctionBytes(func);
ExtendedFunctionDis d(&zone, module(), func_index, &detected, func->sig,
code.begin(), code.end(), func->code.offset(),
names());
if (mode == OutputMode::kWat) {
d.DecodeAsWat(sb, {0, 1});
} else if (mode == OutputMode::kHexDump) {
d.HexDump(sb, FunctionBodyDisassembler::kPrintHeader);
}
// Print any types that were used by the function.
sb.NextLine(0);
ModuleDisassembler md(sb, module(), names(), wire_bytes_, &allocator_);
for (uint32_t type_index : d.used_types()) {
md.PrintTypeDefinition(type_index, {0, 1},
NamesProvider::kIndexAsComment);
}
sb.WriteTo(out_);
}
void WatForModule() {
DCHECK_EQ(status_, kModuleReady);
MultiLineStringBuilder sb;
ModuleDisassembler md(sb, module(), names(), wire_bytes_, &allocator_);
md.PrintModule({0, 2});
sb.WriteTo(out_);
}
void HexdumpForModule() {
DCHECK_NE(status_, kNotReady);
DCHECK_IMPLIES(status_ == kIoInitialized,
module() == nullptr && names() == nullptr);
MultiLineStringBuilder sb;
HexDumpModuleDis md(sb, module(), names(), wire_bytes_, &allocator_);
md.PrintModule();
sb.WriteTo(out_);
}
private:
static constexpr int kModuleHeaderSize = 8;
class Output {
public:
explicit Output(const char* filename) {
if (strcmp(filename, "-") == 0) {
mode_ = kStdout;
} else {
mode_ = kFile;
filestream_.emplace(filename, std::ios::out | std::ios::binary);
if (!filestream_->is_open()) {
std::cerr << "Failed to open " << filename << " for writing!\n";
mode_ = kError;
}
}
}
~Output() {
if (mode_ == kFile) filestream_->close();
}
bool ok() { return mode_ != kError; }
std::ostream& get() {
return mode_ == kFile ? filestream_.value() : std::cout;
}
private:
enum Mode { kFile, kStdout, kError };
base::Optional<std::ofstream> filestream_;
Mode mode_;
};
bool LoadFile(std::string path) {
if (path == "-") return LoadFileFromStream(std::cin);
std::ifstream input(path, std::ios::binary);
if (!input.is_open()) {
std::cerr << "Failed to open " << path << "!\n";
return false;
}
return LoadFileFromStream(input);
}
bool LoadFileFromStream(std::istream& input) {
int c0 = input.get();
int c1 = input.get();
int c2 = input.get();
int c3 = input.peek();
input.putback(c2);
input.putback(c1);
input.putback(c0);
if (c0 == 0 && c1 == 'a' && c2 == 's' && c3 == 'm') {
// Wasm binary module.
raw_bytes_ = std::vector<byte>(std::istreambuf_iterator<char>(input), {});
return true;
}
if (TryParseLiteral(input, raw_bytes_)) return true;
std::cerr << "That's not a Wasm module!\n";
return false;
}
bool IsWhitespace(int c) {
return c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == '\v';
}
// Attempts to read a module in "array literal" syntax:
// - Bytes must be separated by ',', may be specified in decimal or hex.
// - The whole module must be enclosed in '[]', anything outside these
// braces is ignored.
// - Whitespace, line comments, and block comments are ignored.
// So in particular, this can consume what --full-hexdump produces.
bool TryParseLiteral(std::istream& input, std::vector<byte>& output_bytes) {
int c = input.get();
// Skip anything before the first opening '['.
while (c != '[' && c != EOF) c = input.get();
enum State { kBeforeValue = 0, kAfterValue = 1, kDecimal = 10, kHex = 16 };
State state = kBeforeValue;
int value = 0;
while (true) {
c = input.get();
// Skip whitespace, except inside values.
if (state < kDecimal) {
while (IsWhitespace(c)) c = input.get();
}
// End of file before ']' is unexpected = invalid.
if (c == EOF) return false;
// Skip comments.
if (c == '/' && input.peek() == '/') {
// Line comment. Skip until '\n'.
do {
c = input.get();
} while (c != '\n' && c != EOF);
continue;
}
if (c == '/' && input.peek() == '*') {
// Block comment. Skip until "*/".
input.get(); // Consume '*' of opening "/*".
do {
c = input.get();
if (c == '*' && input.peek() == '/') {
input.get(); // Consume '/'.
break;
}
} while (c != EOF);
continue;
}
if (state == kBeforeValue) {
if (c == '0' && (input.peek() == 'x' || input.peek() == 'X')) {
input.get(); // Consume the 'x'.
state = kHex;
continue;
}
if (c >= '0' && c <= '9') {
state = kDecimal;
// Fall through to handling kDecimal below.
} else if (c == ']') {
return true;
} else {
return false;
}
}
DCHECK(state == kDecimal || state == kHex || state == kAfterValue);
if (c == ',') {
DCHECK_LT(value, 256);
output_bytes.push_back(static_cast<byte>(value));
state = kBeforeValue;
value = 0;
continue;
}
if (c == ']') {
DCHECK_LT(value, 256);
output_bytes.push_back(static_cast<byte>(value));
return true;
}
if (state == kAfterValue) {
// Didn't take the ',' or ']' paths above, anything else is invalid.
DCHECK(c != ',' && c != ']');
return false;
}
DCHECK(state == kDecimal || state == kHex);
if (IsWhitespace(c)) {
state = kAfterValue;
continue;
}
int v;
if (c >= '0' && c <= '9') {
v = c - '0';
} else if (state == kHex && (c | 0x20) >= 'a' && (c | 0x20) <= 'f') {
// Setting the "0x20" bit maps uppercase onto lowercase letters.
v = (c | 0x20) - 'a' + 10;
} else {
return false;
}
value = value * state + v;
if (value > 0xFF) return false;
}
}
byte* start() { return raw_bytes_.data(); }
byte* end() { return start() + raw_bytes_.size(); }
const WasmModule* module() { return module_.get(); }
NamesProvider* names() { return names_provider_.get(); }
AccountingAllocator allocator_;
Output output_;
std::ostream& out_;
Status status_{kNotReady};
std::vector<byte> raw_bytes_;
ModuleWireBytes wire_bytes_{{}};
std::shared_ptr<WasmModule> module_;
std::unique_ptr<NamesProvider> names_provider_;
};
} // namespace wasm
} // namespace internal
} // namespace v8
using FormatConverter = v8::internal::wasm::FormatConverter;
using OutputMode = v8::internal::wasm::OutputMode;
using MultiLineStringBuilder = v8::internal::wasm::MultiLineStringBuilder;
enum class Action {
kUnset,
kHelp,
kListFunctions,
kSectionStats,
kInstructionStats,
kFullWat,
kFullHexdump,
kSingleWat,
kSingleHexdump,
kStrip,
};
struct Options {
const char* input = nullptr;
const char* output = nullptr;
Action action = Action::kUnset;
int func_index = -1;
};
bool ParseInt(char* s, int* out) {
char* end;
if (s[0] == '\0') return false;
errno = 0;
long l = strtol(s, &end, 10);
if (errno != 0 || *end != '\0' || l > std::numeric_limits<int>::max() ||
l < std::numeric_limits<int>::min()) {
return false;
}
*out = static_cast<int>(l);
return true;
}
int ParseOptions(int argc, char** argv, Options* options) {
for (int i = 1; i < argc; i++) {
if (strcmp(argv[i], "--help") == 0 || strcmp(argv[i], "-h") == 0 ||
strcmp(argv[i], "help") == 0) {
options->action = Action::kHelp;
} else if (strcmp(argv[i], "--list-functions") == 0) {
options->action = Action::kListFunctions;
} else if (strcmp(argv[i], "--section-stats") == 0) {
options->action = Action::kSectionStats;
} else if (strcmp(argv[i], "--instruction-stats") == 0) {
options->action = Action::kInstructionStats;
} else if (strcmp(argv[i], "--full-wat") == 0) {
options->action = Action::kFullWat;
} else if (strcmp(argv[i], "--full-hexdump") == 0) {
options->action = Action::kFullHexdump;
} else if (strcmp(argv[i], "--single-wat") == 0) {
options->action = Action::kSingleWat;
if (i == argc - 1 || !ParseInt(argv[++i], &options->func_index)) {
return PrintHelp(argv);
}
} else if (strncmp(argv[i], "--single-wat=", 13) == 0) {
options->action = Action::kSingleWat;
if (!ParseInt(argv[i] + 13, &options->func_index)) return PrintHelp(argv);
} else if (strcmp(argv[i], "--single-hexdump") == 0) {
options->action = Action::kSingleHexdump;
if (i == argc - 1 || !ParseInt(argv[++i], &options->func_index)) {
return PrintHelp(argv);
}
} else if (strncmp(argv[i], "--single-hexdump=", 17) == 0) {
if (!ParseInt(argv[i] + 17, &options->func_index)) return PrintHelp(argv);
} else if (strcmp(argv[i], "--strip") == 0) {
options->action = Action::kStrip;
} else if (strcmp(argv[i], "-o") == 0) {
if (i == argc - 1) return PrintHelp(argv);
options->output = argv[++i];
} else if (strncmp(argv[i], "-o=", 3) == 0) {
options->output = argv[i] + 3;
} else if (strcmp(argv[i], "--output") == 0) {
if (i == argc - 1) return PrintHelp(argv);
options->output = argv[++i];
} else if (strncmp(argv[i], "--output=", 9) == 0) {
options->output = argv[i] + 9;
} else if (options->input != nullptr) {
return PrintHelp(argv);
} else {
options->input = argv[i];
}
}
#if V8_OS_POSIX
// When piping data into wami, specifying the input as "-" is optional.
if (options->input == nullptr && !isatty(STDIN_FILENO)) {
options->input = "-";
}
#endif
if (options->output == nullptr) {
// Refuse to send binary data to the terminal.
if (options->action == Action::kStrip) {
#if V8_OS_POSIX
// Piping binary output to another command is okay.
if (isatty(STDOUT_FILENO)) return PrintHelp(argv);
#else
return PrintHelp(argv);
#endif
}
options->output = "-"; // Default output: stdout.
}
if (options->action == Action::kUnset || options->input == nullptr) {
return PrintHelp(argv);
}
return 0;
}
int main(int argc, char** argv) {
Options options;
if (ParseOptions(argc, argv, &options) != 0) return 1;
if (options.action == Action::kHelp) {
PrintHelp(argv);
return 0;
}
// Bootstrap the basics.
v8::V8::InitializeICUDefaultLocation(argv[0]);
v8::V8::InitializeExternalStartupData(argv[0]);
std::unique_ptr<v8::Platform> platform = v8::platform::NewDefaultPlatform();
v8::V8::InitializePlatform(platform.get());
v8::V8::Initialize();
FormatConverter fc(options.input, options.output);
if (fc.status() == FormatConverter::kNotReady) return 1;
// Allow hex dumping invalid modules.
if (fc.status() != FormatConverter::kModuleReady &&
options.action != Action::kFullHexdump) {
std::cerr << "Consider using --full-hexdump to learn more.\n";
return 1;
}
switch (options.action) {
case Action::kListFunctions:
fc.ListFunctions();
break;
case Action::kSectionStats:
fc.SectionStats();
break;
case Action::kInstructionStats:
fc.InstructionStats();
break;
case Action::kSingleWat:
fc.DisassembleFunction(options.func_index, OutputMode::kWat);
break;
case Action::kSingleHexdump:
fc.DisassembleFunction(options.func_index, OutputMode::kHexDump);
break;
case Action::kFullWat:
fc.WatForModule();
break;
case Action::kFullHexdump:
fc.HexdumpForModule();
break;
case Action::kStrip:
fc.Strip();
break;
case Action::kHelp:
case Action::kUnset:
UNREACHABLE();
}
v8::V8::Dispose();
v8::V8::DisposePlatform();
return 0;
}
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