forked from WebAssembly/binaryen
/
wasm-binary.cpp
2722 lines (2516 loc) · 107 KB
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wasm-binary.cpp
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/*
* Copyright 2016 WebAssembly Community Group participants
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <algorithm>
#include <fstream>
#include "wasm-binary.h"
#include "wasm-stack.h"
#include "ir/module-utils.h"
#include "support/bits.h"
namespace wasm {
void WasmBinaryWriter::prepare() {
// we need function types for all our functions
for (auto& func : wasm->functions) {
if (func->type.isNull()) {
func->type = ensureFunctionType(getSig(func.get()), wasm)->name;
}
// TODO: depending on upstream flux https://github.com/WebAssembly/spec/pull/301 might want this: assert(!func->type.isNull());
}
ModuleUtils::BinaryIndexes indexes(*wasm);
mappedFunctions = std::move(indexes.functionIndexes);
mappedGlobals = std::move(indexes.globalIndexes);
importInfo = wasm::make_unique<ImportInfo>(*wasm);
}
void WasmBinaryWriter::write() {
writeHeader();
writeEarlyUserSections();
initializeDebugInfo();
if (sourceMap) {
writeSourceMapProlog();
}
writeTypes();
writeImports();
writeFunctionSignatures();
writeFunctionTableDeclaration();
writeMemory();
writeGlobals();
writeExports();
writeStart();
writeTableElements();
writeFunctions();
writeDataSegments();
if (debugInfo) writeNames();
if (sourceMap && !sourceMapUrl.empty()) writeSourceMapUrl();
if (symbolMap.size() > 0) writeSymbolMap();
if (sourceMap) {
writeSourceMapEpilog();
}
writeLateUserSections();
finishUp();
}
void WasmBinaryWriter::writeHeader() {
if (debug) std::cerr << "== writeHeader" << std::endl;
o << int32_t(BinaryConsts::Magic); // magic number \0asm
o << int32_t(BinaryConsts::Version);
}
int32_t WasmBinaryWriter::writeU32LEBPlaceholder() {
int32_t ret = o.size();
o << int32_t(0);
o << int8_t(0);
return ret;
}
void WasmBinaryWriter::writeResizableLimits(Address initial, Address maximum,
bool hasMaximum, bool shared) {
uint32_t flags =
(hasMaximum ? (uint32_t) BinaryConsts::HasMaximum : 0U) |
(shared ? (uint32_t) BinaryConsts::IsShared : 0U);
o << U32LEB(flags);
o << U32LEB(initial);
if (hasMaximum) {
o << U32LEB(maximum);
}
}
template<typename T>
int32_t WasmBinaryWriter::startSection(T code) {
o << U32LEB(code);
if (sourceMap) sourceMapLocationsSizeAtSectionStart = sourceMapLocations.size();
return writeU32LEBPlaceholder(); // section size to be filled in later
}
void WasmBinaryWriter::finishSection(int32_t start) {
int32_t size = o.size() - start - MaxLEB32Bytes; // section size does not include the reserved bytes of the size field itself
auto sizeFieldSize = o.writeAt(start, U32LEB(size));
if (sizeFieldSize != MaxLEB32Bytes) {
// we can save some room, nice
assert(sizeFieldSize < MaxLEB32Bytes);
std::move(&o[start] + MaxLEB32Bytes, &o[start] + MaxLEB32Bytes + size, &o[start] + sizeFieldSize);
auto adjustment = MaxLEB32Bytes - sizeFieldSize;
o.resize(o.size() - adjustment);
if (sourceMap) {
for (auto i = sourceMapLocationsSizeAtSectionStart; i < sourceMapLocations.size(); ++i) {
sourceMapLocations[i].first -= adjustment;
}
}
}
}
int32_t WasmBinaryWriter::startSubsection(BinaryConsts::UserSections::Subsection code) {
return startSection(code);
}
void WasmBinaryWriter::finishSubsection(int32_t start) {
finishSection(start);
}
void WasmBinaryWriter::writeStart() {
if (!wasm->start.is()) return;
if (debug) std::cerr << "== writeStart" << std::endl;
auto start = startSection(BinaryConsts::Section::Start);
o << U32LEB(getFunctionIndex(wasm->start.str));
finishSection(start);
}
void WasmBinaryWriter::writeMemory() {
if (!wasm->memory.exists || wasm->memory.imported()) return;
if (debug) std::cerr << "== writeMemory" << std::endl;
auto start = startSection(BinaryConsts::Section::Memory);
o << U32LEB(1); // Define 1 memory
writeResizableLimits(wasm->memory.initial, wasm->memory.max,
wasm->memory.hasMax(), wasm->memory.shared);
finishSection(start);
}
void WasmBinaryWriter::writeTypes() {
if (wasm->functionTypes.size() == 0) return;
if (debug) std::cerr << "== writeTypes" << std::endl;
auto start = startSection(BinaryConsts::Section::Type);
o << U32LEB(wasm->functionTypes.size());
for (auto& type : wasm->functionTypes) {
if (debug) std::cerr << "write one" << std::endl;
o << S32LEB(BinaryConsts::EncodedType::Func);
o << U32LEB(type->params.size());
for (auto param : type->params) {
o << binaryType(param);
}
if (type->result == none) {
o << U32LEB(0);
} else {
o << U32LEB(1);
o << binaryType(type->result);
}
}
finishSection(start);
}
int32_t WasmBinaryWriter::getFunctionTypeIndex(Name type) {
// TODO: optimize
for (size_t i = 0; i < wasm->functionTypes.size(); i++) {
if (wasm->functionTypes[i]->name == type) return i;
}
abort();
}
void WasmBinaryWriter::writeImports() {
auto num = importInfo->getNumImports();
if (num == 0) return;
if (debug) std::cerr << "== writeImports" << std::endl;
auto start = startSection(BinaryConsts::Section::Import);
o << U32LEB(num);
auto writeImportHeader = [&](Importable* import) {
writeInlineString(import->module.str);
writeInlineString(import->base.str);
};
ModuleUtils::iterImportedFunctions(*wasm, [&](Function* func) {
if (debug) std::cerr << "write one function" << std::endl;
writeImportHeader(func);
o << U32LEB(int32_t(ExternalKind::Function));
o << U32LEB(getFunctionTypeIndex(func->type));
});
ModuleUtils::iterImportedGlobals(*wasm, [&](Global* global) {
if (debug) std::cerr << "write one global" << std::endl;
writeImportHeader(global);
o << U32LEB(int32_t(ExternalKind::Global));
o << binaryType(global->type);
o << U32LEB(global->mutable_);
});
if (wasm->memory.imported()) {
if (debug) std::cerr << "write one memory" << std::endl;
writeImportHeader(&wasm->memory);
o << U32LEB(int32_t(ExternalKind::Memory));
writeResizableLimits(wasm->memory.initial, wasm->memory.max,
wasm->memory.hasMax(), wasm->memory.shared);
}
if (wasm->table.imported()) {
if (debug) std::cerr << "write one table" << std::endl;
writeImportHeader(&wasm->table);
o << U32LEB(int32_t(ExternalKind::Table));
o << S32LEB(BinaryConsts::EncodedType::AnyFunc);
writeResizableLimits(wasm->table.initial, wasm->table.max, wasm->table.hasMax(), /*shared=*/false);
}
finishSection(start);
}
void WasmBinaryWriter::writeFunctionSignatures() {
if (importInfo->getNumDefinedFunctions() == 0) return;
if (debug) std::cerr << "== writeFunctionSignatures" << std::endl;
auto start = startSection(BinaryConsts::Section::Function);
o << U32LEB(importInfo->getNumDefinedFunctions());
ModuleUtils::iterDefinedFunctions(*wasm, [&](Function* func) {
if (debug) std::cerr << "write one" << std::endl;
o << U32LEB(getFunctionTypeIndex(func->type));
});
finishSection(start);
}
void WasmBinaryWriter::writeExpression(Expression* curr) {
ExpressionStackWriter<WasmBinaryWriter>(curr, *this, o, debug);
}
void WasmBinaryWriter::writeFunctions() {
if (importInfo->getNumDefinedFunctions() == 0) return;
if (debug) std::cerr << "== writeFunctions" << std::endl;
auto start = startSection(BinaryConsts::Section::Code);
o << U32LEB(importInfo->getNumDefinedFunctions());
ModuleUtils::iterDefinedFunctions(*wasm, [&](Function* func) {
size_t sourceMapLocationsSizeAtFunctionStart = sourceMapLocations.size();
if (debug) std::cerr << "write one at" << o.size() << std::endl;
size_t sizePos = writeU32LEBPlaceholder();
size_t start = o.size();
if (debug) std::cerr << "writing" << func->name << std::endl;
// Emit Stack IR if present, and if we can
if (func->stackIR && !sourceMap) {
if (debug) std::cerr << "write Stack IR" << std::endl;
StackIRFunctionStackWriter<WasmBinaryWriter>(func, *this, o, debug);
} else {
if (debug) std::cerr << "write Binaryen IR" << std::endl;
FunctionStackWriter<WasmBinaryWriter>(func, *this, o, sourceMap, debug);
}
size_t size = o.size() - start;
assert(size <= std::numeric_limits<uint32_t>::max());
if (debug) std::cerr << "body size: " << size << ", writing at " << sizePos << ", next starts at " << o.size() << std::endl;
auto sizeFieldSize = o.writeAt(sizePos, U32LEB(size));
if (sizeFieldSize != MaxLEB32Bytes) {
// we can save some room, nice
assert(sizeFieldSize < MaxLEB32Bytes);
std::move(&o[start], &o[start] + size, &o[sizePos] + sizeFieldSize);
auto adjustment = MaxLEB32Bytes - sizeFieldSize;
o.resize(o.size() - adjustment);
if (sourceMap) {
for (auto i = sourceMapLocationsSizeAtFunctionStart; i < sourceMapLocations.size(); ++i) {
sourceMapLocations[i].first -= adjustment;
}
}
}
tableOfContents.functionBodies.emplace_back(func->name, sizePos + sizeFieldSize, size);
});
finishSection(start);
}
void WasmBinaryWriter::writeGlobals() {
if (importInfo->getNumDefinedGlobals() == 0) return;
if (debug) std::cerr << "== writeglobals" << std::endl;
auto start = startSection(BinaryConsts::Section::Global);
auto num = importInfo->getNumDefinedGlobals();
o << U32LEB(num);
ModuleUtils::iterDefinedGlobals(*wasm, [&](Global* global) {
if (debug) std::cerr << "write one" << std::endl;
o << binaryType(global->type);
o << U32LEB(global->mutable_);
writeExpression(global->init);
o << int8_t(BinaryConsts::End);
});
finishSection(start);
}
void WasmBinaryWriter::writeExports() {
if (wasm->exports.size() == 0) return;
if (debug) std::cerr << "== writeexports" << std::endl;
auto start = startSection(BinaryConsts::Section::Export);
o << U32LEB(wasm->exports.size());
for (auto& curr : wasm->exports) {
if (debug) std::cerr << "write one" << std::endl;
writeInlineString(curr->name.str);
o << U32LEB(int32_t(curr->kind));
switch (curr->kind) {
case ExternalKind::Function: o << U32LEB(getFunctionIndex(curr->value)); break;
case ExternalKind::Table: o << U32LEB(0); break;
case ExternalKind::Memory: o << U32LEB(0); break;
case ExternalKind::Global: o << U32LEB(getGlobalIndex(curr->value)); break;
default: WASM_UNREACHABLE();
}
}
finishSection(start);
}
void WasmBinaryWriter::writeDataSegments() {
if (wasm->memory.segments.size() == 0) return;
if (wasm->memory.segments.size() > WebLimitations::MaxDataSegments) {
std::cerr << "Some VMs may not accept this binary because it has a large "
<< "number of data segments. Run the limit-segments pass to "
<< "merge segments." << std::endl;
}
auto start = startSection(BinaryConsts::Section::Data);
o << U32LEB(wasm->memory.segments.size());
for (auto& segment : wasm->memory.segments) {
uint32_t flags = 0;
if (segment.isPassive) {
flags |= BinaryConsts::IsPassive;
}
o << U32LEB(flags);
if (!segment.isPassive) {
writeExpression(segment.offset);
o << int8_t(BinaryConsts::End);
}
writeInlineBuffer(segment.data.data(), segment.data.size());
}
finishSection(start);
}
uint32_t WasmBinaryWriter::getFunctionIndex(Name name) {
assert(mappedFunctions.count(name));
return mappedFunctions[name];
}
uint32_t WasmBinaryWriter::getGlobalIndex(Name name) {
assert(mappedGlobals.count(name));
return mappedGlobals[name];
}
void WasmBinaryWriter::writeFunctionTableDeclaration() {
if (!wasm->table.exists || wasm->table.imported()) return;
if (debug) std::cerr << "== writeFunctionTableDeclaration" << std::endl;
auto start = startSection(BinaryConsts::Section::Table);
o << U32LEB(1); // Declare 1 table.
o << S32LEB(BinaryConsts::EncodedType::AnyFunc);
writeResizableLimits(wasm->table.initial, wasm->table.max, wasm->table.hasMax(), /*shared=*/false);
finishSection(start);
}
void WasmBinaryWriter::writeTableElements() {
if (!wasm->table.exists) return;
if (debug) std::cerr << "== writeTableElements" << std::endl;
auto start = startSection(BinaryConsts::Section::Element);
o << U32LEB(wasm->table.segments.size());
for (auto& segment : wasm->table.segments) {
o << U32LEB(0); // Table index; 0 in the MVP (and binaryen IR only has 1 table)
writeExpression(segment.offset);
o << int8_t(BinaryConsts::End);
o << U32LEB(segment.data.size());
for (auto name : segment.data) {
o << U32LEB(getFunctionIndex(name));
}
}
finishSection(start);
}
void WasmBinaryWriter::writeNames() {
bool hasContents = false;
if (wasm->functions.size() > 0) {
hasContents = true;
getFunctionIndex(wasm->functions[0]->name); // generate mappedFunctions
}
if (!hasContents) return;
if (debug) std::cerr << "== writeNames" << std::endl;
auto start = startSection(BinaryConsts::Section::User);
writeInlineString(BinaryConsts::UserSections::Name);
auto substart = startSubsection(BinaryConsts::UserSections::Subsection::NameFunction);
o << U32LEB(mappedFunctions.size());
Index emitted = 0;
auto add = [&](Function* curr) {
o << U32LEB(emitted);
writeEscapedName(curr->name.str);
emitted++;
};
ModuleUtils::iterImportedFunctions(*wasm, add);
ModuleUtils::iterDefinedFunctions(*wasm, add);
assert(emitted == mappedFunctions.size());
finishSubsection(substart);
/* TODO: locals */
finishSection(start);
}
void WasmBinaryWriter::writeSourceMapUrl() {
if (debug) std::cerr << "== writeSourceMapUrl" << std::endl;
auto start = startSection(BinaryConsts::Section::User);
writeInlineString(BinaryConsts::UserSections::SourceMapUrl);
writeInlineString(sourceMapUrl.c_str());
finishSection(start);
}
void WasmBinaryWriter::writeSymbolMap() {
std::ofstream file(symbolMap);
auto write = [&](Function* func) {
file << getFunctionIndex(func->name) << ":" << func->name.str << std::endl;
};
ModuleUtils::iterImportedFunctions(*wasm, write);
ModuleUtils::iterDefinedFunctions(*wasm, write);
file.close();
}
void WasmBinaryWriter::initializeDebugInfo() {
lastDebugLocation = { 0, /* lineNumber = */ 1, 0 };
}
void WasmBinaryWriter::writeSourceMapProlog() {
*sourceMap << "{\"version\":3,\"sources\":[";
for (size_t i = 0; i < wasm->debugInfoFileNames.size(); i++) {
if (i > 0) *sourceMap << ",";
// TODO respect JSON string encoding, e.g. quotes and control chars.
*sourceMap << "\"" << wasm->debugInfoFileNames[i] << "\"";
}
*sourceMap << "],\"names\":[],\"mappings\":\"";
}
static void writeBase64VLQ(std::ostream& out, int32_t n) {
uint32_t value = n >= 0 ? n << 1 : ((-n) << 1) | 1;
while (1) {
uint32_t digit = value & 0x1F;
value >>= 5;
if (!value) {
// last VLQ digit -- base64 codes 'A'..'Z', 'a'..'f'
out << char(digit < 26 ? 'A' + digit : 'a' + digit - 26);
break;
}
// more VLG digit will follow -- add continuation bit (0x20),
// base64 codes 'g'..'z', '0'..'9', '+', '/'
out << char(digit < 20 ? 'g' + digit : digit < 30 ? '0' + digit - 20 : digit == 30 ? '+' : '/');
}
}
void WasmBinaryWriter::writeSourceMapEpilog() {
// write source map entries
size_t lastOffset = 0;
Function::DebugLocation lastLoc = { 0, /* lineNumber = */ 1, 0 };
for (const auto &offsetAndlocPair : sourceMapLocations) {
if (lastOffset > 0) {
*sourceMap << ",";
}
size_t offset = offsetAndlocPair.first;
const Function::DebugLocation& loc = *offsetAndlocPair.second;
writeBase64VLQ(*sourceMap, int32_t(offset - lastOffset));
writeBase64VLQ(*sourceMap, int32_t(loc.fileIndex - lastLoc.fileIndex));
writeBase64VLQ(*sourceMap, int32_t(loc.lineNumber - lastLoc.lineNumber));
writeBase64VLQ(*sourceMap, int32_t(loc.columnNumber - lastLoc.columnNumber));
lastLoc = loc;
lastOffset = offset;
}
*sourceMap << "\"}";
}
void WasmBinaryWriter::writeEarlyUserSections() {
// The dylink section must be the first in the module, per
// the spec, to allow simple parsing by loaders.
for (auto& section : wasm->userSections) {
if (section.name == BinaryConsts::UserSections::Dylink) {
writeUserSection(section);
}
}
}
void WasmBinaryWriter::writeLateUserSections() {
for (auto& section : wasm->userSections) {
if (section.name != BinaryConsts::UserSections::Dylink) {
writeUserSection(section);
}
}
}
void WasmBinaryWriter::writeUserSection(const UserSection& section) {
auto start = startSection(0);
writeInlineString(section.name.c_str());
for (size_t i = 0; i < section.data.size(); i++) {
o << uint8_t(section.data[i]);
}
finishSection(start);
}
void WasmBinaryWriter::writeDebugLocation(const Function::DebugLocation& loc) {
if (loc == lastDebugLocation) {
return;
}
auto offset = o.size();
sourceMapLocations.emplace_back(offset, &loc);
lastDebugLocation = loc;
}
void WasmBinaryWriter::writeDebugLocation(Expression* curr, Function* func) {
auto& debugLocations = func->debugLocations;
auto iter = debugLocations.find(curr);
if (iter != debugLocations.end()) {
writeDebugLocation(iter->second);
}
}
void WasmBinaryWriter::writeInlineString(const char* name) {
int32_t size = strlen(name);
o << U32LEB(size);
for (int32_t i = 0; i < size; i++) {
o << int8_t(name[i]);
}
}
static bool isHexDigit(char ch) {
return (ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'f') || (ch >= 'A' && ch <= 'F');
}
static int decodeHexNibble(char ch) {
return ch <= '9' ? ch & 15 : (ch & 15) + 9;
}
void WasmBinaryWriter::writeEscapedName(const char* name) {
if (!strpbrk(name, "\\")) {
writeInlineString(name);
return;
}
// decode escaped by escapeName (see below) function names
std::string unescaped;
int32_t size = strlen(name);
for (int32_t i = 0; i < size;) {
char ch = name[i++];
// support only `\xx` escapes; ignore invalid or unsupported escapes
if (ch != '\\' || i + 1 >= size || !isHexDigit(name[i]) || !isHexDigit(name[i + 1])) {
unescaped.push_back(ch);
continue;
}
unescaped.push_back(char((decodeHexNibble(name[i]) << 4) | decodeHexNibble(name[i + 1])));
i += 2;
}
writeInlineString(unescaped.c_str());
}
void WasmBinaryWriter::writeInlineBuffer(const char* data, size_t size) {
o << U32LEB(size);
for (size_t i = 0; i < size; i++) {
o << int8_t(data[i]);
}
}
void WasmBinaryWriter::emitBuffer(const char* data, size_t size) {
assert(size > 0);
buffersToWrite.emplace_back(data, size, o.size());
o << uint32_t(0); // placeholder, we'll fill in the pointer to the buffer later when we have it
}
void WasmBinaryWriter::emitString(const char *str) {
if (debug) std::cerr << "emitString " << str << std::endl;
emitBuffer(str, strlen(str) + 1);
}
void WasmBinaryWriter::finishUp() {
if (debug) std::cerr << "finishUp" << std::endl;
// finish buffers
for (const auto& buffer : buffersToWrite) {
if (debug) std::cerr << "writing buffer" << (int)buffer.data[0] << "," << (int)buffer.data[1] << " at " << o.size() << " and pointer is at " << buffer.pointerLocation << std::endl;
o.writeAt(buffer.pointerLocation, (uint32_t)o.size());
for (size_t i = 0; i < buffer.size; i++) {
o << (uint8_t)buffer.data[i];
}
}
}
// reader
void WasmBinaryBuilder::read() {
readHeader();
readSourceMapHeader();
// read sections until the end
while (more()) {
uint32_t sectionCode = getU32LEB();
uint32_t payloadLen = getU32LEB();
if (pos + payloadLen > input.size()) throwError("Section extends beyond end of input");
auto oldPos = pos;
// note the section in the list of seen sections, as almost no sections can appear more than once,
// and verify those that shouldn't do not.
if (sectionCode != BinaryConsts::Section::User && sectionCode != BinaryConsts::Section::Code) {
if (!seenSections.insert(BinaryConsts::Section(sectionCode)).second) {
throwError("section seen more than once: " + std::to_string(sectionCode));
}
}
switch (sectionCode) {
case BinaryConsts::Section::Start: readStart(); break;
case BinaryConsts::Section::Memory: readMemory(); break;
case BinaryConsts::Section::Type: readSignatures(); break;
case BinaryConsts::Section::Import: readImports(); break;
case BinaryConsts::Section::Function: readFunctionSignatures(); break;
case BinaryConsts::Section::Code: readFunctions(); break;
case BinaryConsts::Section::Export: readExports(); break;
case BinaryConsts::Section::Element: readTableElements(); break;
case BinaryConsts::Section::Global: {
readGlobals();
// imports can read global imports, so we run getGlobalName and create the mapping
// but after we read globals, we need to add the internal globals too, so do that here
mappedGlobals.clear(); // wipe the mapping
getGlobalName(-1); // force rebuild
break;
}
case BinaryConsts::Section::Data: readDataSegments(); break;
case BinaryConsts::Section::Table: readFunctionTableDeclaration(); break;
default: {
readUserSection(payloadLen);
if (pos > oldPos + payloadLen) {
throwError("bad user section size, started at " + std::to_string(oldPos) + " plus payload " + std::to_string(payloadLen) + " not being equal to new position " + std::to_string(pos));
}
pos = oldPos + payloadLen;
}
}
// make sure we advanced exactly past this section
if (pos != oldPos + payloadLen) {
throwError("bad section size, started at " + std::to_string(oldPos) + " plus payload " + std::to_string(payloadLen) + " not being equal to new position " + std::to_string(pos));
}
}
processFunctions();
}
void WasmBinaryBuilder::readUserSection(size_t payloadLen) {
auto oldPos = pos;
Name sectionName = getInlineString();
size_t read = pos - oldPos;
if (read > payloadLen) {
throwError("bad user section size");
}
payloadLen -= read;
if (sectionName.equals(BinaryConsts::UserSections::Name)) {
readNames(payloadLen);
} else {
// an unfamiliar custom section
if (sectionName.equals(BinaryConsts::UserSections::Linking)) {
std::cerr << "warning: linking section is present, so this is not a standard wasm file - binaryen cannot handle this properly!\n";
}
wasm.userSections.resize(wasm.userSections.size() + 1);
auto& section = wasm.userSections.back();
section.name = sectionName.str;
auto sectionSize = payloadLen;
section.data.resize(sectionSize);
for (size_t i = 0; i < sectionSize; i++) {
section.data[i] = getInt8();
}
}
}
uint8_t WasmBinaryBuilder::getInt8() {
if (!more()) throwError("unexpected end of input");
if (debug) std::cerr << "getInt8: " << (int)(uint8_t)input[pos] << " (at " << pos << ")" << std::endl;
return input[pos++];
}
uint16_t WasmBinaryBuilder::getInt16() {
if (debug) std::cerr << "<==" << std::endl;
auto ret = uint16_t(getInt8());
ret |= uint16_t(getInt8()) << 8;
if (debug) std::cerr << "getInt16: " << ret << "/0x" << std::hex << ret << std::dec << " ==>" << std::endl;
return ret;
}
uint32_t WasmBinaryBuilder::getInt32() {
if (debug) std::cerr << "<==" << std::endl;
auto ret = uint32_t(getInt16());
ret |= uint32_t(getInt16()) << 16;
if (debug) std::cerr << "getInt32: " << ret << "/0x" << std::hex << ret << std::dec <<" ==>" << std::endl;
return ret;
}
uint64_t WasmBinaryBuilder::getInt64() {
if (debug) std::cerr << "<==" << std::endl;
auto ret = uint64_t(getInt32());
ret |= uint64_t(getInt32()) << 32;
if (debug) std::cerr << "getInt64: " << ret << "/0x" << std::hex << ret << std::dec << " ==>" << std::endl;
return ret;
}
uint8_t WasmBinaryBuilder::getLaneIndex(size_t lanes) {
if (debug) std::cerr << "<==" << std::endl;
auto ret = getInt8();
if (ret >= lanes) throwError("Illegal lane index");
if (debug) std::cerr << "getLaneIndex(" << lanes << "): " << ret << " ==>" << std::endl;
return ret;
}
Literal WasmBinaryBuilder::getFloat32Literal() {
if (debug) std::cerr << "<==" << std::endl;
auto ret = Literal(getInt32());
ret = ret.castToF32();
if (debug) std::cerr << "getFloat32: " << ret << " ==>" << std::endl;
return ret;
}
Literal WasmBinaryBuilder::getFloat64Literal() {
if (debug) std::cerr << "<==" << std::endl;
auto ret = Literal(getInt64());
ret = ret.castToF64();
if (debug) std::cerr << "getFloat64: " << ret << " ==>" << std::endl;
return ret;
}
Literal WasmBinaryBuilder::getVec128Literal() {
if (debug) std::cerr << "<==" << std::endl;
std::array<uint8_t, 16> bytes;
for (auto i = 0; i < 16; ++i) {
bytes[i] = getInt8();
}
auto ret = Literal(bytes.data());
if (debug) std::cerr << "getVec128: " << ret << " ==>" << std::endl;
return ret;
}
uint32_t WasmBinaryBuilder::getU32LEB() {
if (debug) std::cerr << "<==" << std::endl;
U32LEB ret;
ret.read([&]() {
return getInt8();
});
if (debug) std::cerr << "getU32LEB: " << ret.value << " ==>" << std::endl;
return ret.value;
}
uint64_t WasmBinaryBuilder::getU64LEB() {
if (debug) std::cerr << "<==" << std::endl;
U64LEB ret;
ret.read([&]() {
return getInt8();
});
if (debug) std::cerr << "getU64LEB: " << ret.value << " ==>" << std::endl;
return ret.value;
}
int32_t WasmBinaryBuilder::getS32LEB() {
if (debug) std::cerr << "<==" << std::endl;
S32LEB ret;
ret.read([&]() {
return (int8_t)getInt8();
});
if (debug) std::cerr << "getS32LEB: " << ret.value << " ==>" << std::endl;
return ret.value;
}
int64_t WasmBinaryBuilder::getS64LEB() {
if (debug) std::cerr << "<==" << std::endl;
S64LEB ret;
ret.read([&]() {
return (int8_t)getInt8();
});
if (debug) std::cerr << "getS64LEB: " << ret.value << " ==>" << std::endl;
return ret.value;
}
Type WasmBinaryBuilder::getType() {
int type = getS32LEB();
switch (type) {
// None only used for block signatures. TODO: Separate out?
case BinaryConsts::EncodedType::Empty: return none;
case BinaryConsts::EncodedType::i32: return i32;
case BinaryConsts::EncodedType::i64: return i64;
case BinaryConsts::EncodedType::f32: return f32;
case BinaryConsts::EncodedType::f64: return f64;
case BinaryConsts::EncodedType::v128: return v128;
default: {
throwError("invalid wasm type: " + std::to_string(type));
}
}
WASM_UNREACHABLE();
}
Type WasmBinaryBuilder::getConcreteType() {
auto type = getType();
if (!isConcreteType(type)) {
throw ParseException("non-concrete type when one expected");
}
return type;
}
Name WasmBinaryBuilder::getInlineString() {
if (debug) std::cerr << "<==" << std::endl;
auto len = getU32LEB();
std::string str;
for (size_t i = 0; i < len; i++) {
auto curr = char(getInt8());
if (curr == 0) {
throwError("inline string contains NULL (0). that is technically valid in wasm, but you shouldn't do it, and it's not supported in binaryen");
}
str = str + curr;
}
if (debug) std::cerr << "getInlineString: " << str << " ==>" << std::endl;
return Name(str);
}
void WasmBinaryBuilder::verifyInt8(int8_t x) {
int8_t y = getInt8();
if (x != y) throwError("surprising value");
}
void WasmBinaryBuilder::verifyInt16(int16_t x) {
int16_t y = getInt16();
if (x != y) throwError("surprising value");
}
void WasmBinaryBuilder::verifyInt32(int32_t x) {
int32_t y = getInt32();
if (x != y) throwError("surprising value");
}
void WasmBinaryBuilder::verifyInt64(int64_t x) {
int64_t y = getInt64();
if (x != y) throwError("surprising value");
}
void WasmBinaryBuilder::ungetInt8() {
assert(pos > 0);
if (debug) std::cerr << "ungetInt8 (at " << pos << ")" << std::endl;
pos--;
}
void WasmBinaryBuilder::readHeader() {
if (debug) std::cerr << "== readHeader" << std::endl;
verifyInt32(BinaryConsts::Magic);
verifyInt32(BinaryConsts::Version);
}
void WasmBinaryBuilder::readStart() {
if (debug) std::cerr << "== readStart" << std::endl;
startIndex = getU32LEB();
}
void WasmBinaryBuilder::readMemory() {
if (debug) std::cerr << "== readMemory" << std::endl;
auto numMemories = getU32LEB();
if (!numMemories) return;
if (numMemories != 1) {
throwError("Must be exactly 1 memory");
}
if (wasm.memory.exists) {
throwError("Memory cannot be both imported and defined");
}
wasm.memory.exists = true;
getResizableLimits(wasm.memory.initial, wasm.memory.max, wasm.memory.shared, Memory::kUnlimitedSize);
}
void WasmBinaryBuilder::readSignatures() {
if (debug) std::cerr << "== readSignatures" << std::endl;
size_t numTypes = getU32LEB();
if (debug) std::cerr << "num: " << numTypes << std::endl;
for (size_t i = 0; i < numTypes; i++) {
if (debug) std::cerr << "read one" << std::endl;
auto curr = make_unique<FunctionType>();
auto form = getS32LEB();
if (form != BinaryConsts::EncodedType::Func) {
throwError("bad signature form " + std::to_string(form));
}
size_t numParams = getU32LEB();
if (debug) std::cerr << "num params: " << numParams << std::endl;
for (size_t j = 0; j < numParams; j++) {
curr->params.push_back(getConcreteType());
}
auto numResults = getU32LEB();
if (numResults == 0) {
curr->result = none;
} else {
if (numResults != 1) {
throwError("signature must have 1 result");
}
curr->result = getType();
}
curr->name = Name::fromInt(wasm.functionTypes.size());
wasm.addFunctionType(std::move(curr));
}
}
Name WasmBinaryBuilder::getFunctionIndexName(Index i) {
if (i >= wasm.functions.size()) {
throwError("invalid function index");
}
return wasm.functions[i]->name;
}
void WasmBinaryBuilder::getResizableLimits(Address& initial, Address& max, bool &shared, Address defaultIfNoMax) {
auto flags = getU32LEB();
initial = getU32LEB();
bool hasMax = (flags & BinaryConsts::HasMaximum) != 0;
bool isShared = (flags & BinaryConsts::IsShared) != 0;
if (isShared && !hasMax) throwError("shared memory must have max size");
shared = isShared;
if (hasMax) max = getU32LEB();
else max = defaultIfNoMax;
}
void WasmBinaryBuilder::readImports() {
if (debug) std::cerr << "== readImports" << std::endl;
size_t num = getU32LEB();
if (debug) std::cerr << "num: " << num << std::endl;
Builder builder(wasm);
for (size_t i = 0; i < num; i++) {
if (debug) std::cerr << "read one" << std::endl;
auto module = getInlineString();
auto base = getInlineString();
auto kind = (ExternalKind)getU32LEB();
// We set a unique prefix for the name based on the kind. This ensures no collisions
// between them, which can't occur here (due to the index i) but could occur later
// due to the names section.
switch (kind) {
case ExternalKind::Function: {
auto name = Name(std::string("fimport$") + std::to_string(i));
auto index = getU32LEB();
if (index >= wasm.functionTypes.size()) {
throwError("invalid function index " + std::to_string(index) + " / " + std::to_string(wasm.functionTypes.size()));
}
auto* functionType = wasm.functionTypes[index].get();
auto params = functionType->params;
auto result = functionType->result;
auto* curr = builder.makeFunction(name, std::move(params), result, {});
curr->module = module;
curr->base = base;
curr->type = functionType->name;
wasm.addFunction(curr);
functionImports.push_back(curr);
break;
}
case ExternalKind::Table: {
wasm.table.module = module;
wasm.table.base = base;
wasm.table.name = Name(std::string("timport$") + std::to_string(i));
auto elementType = getS32LEB();
WASM_UNUSED(elementType);
if (elementType != BinaryConsts::EncodedType::AnyFunc) throwError("Imported table type is not AnyFunc");
wasm.table.exists = true;
bool is_shared;
getResizableLimits(wasm.table.initial, wasm.table.max, is_shared, Table::kUnlimitedSize);
if (is_shared) throwError("Tables may not be shared");
break;
}
case ExternalKind::Memory: {
wasm.memory.module = module;
wasm.memory.base = base;
wasm.memory.name = Name(std::to_string(i));
wasm.memory.exists = true;
getResizableLimits(wasm.memory.initial, wasm.memory.max, wasm.memory.shared, Memory::kUnlimitedSize);
break;
}
case ExternalKind::Global: {
auto name = Name(std::string("gimport$") + std::to_string(i));
auto type = getConcreteType();
auto mutable_ = getU32LEB();
auto* curr = builder.makeGlobal(name, type, nullptr, mutable_ ? Builder::Mutable : Builder::Immutable);
curr->module = module;
curr->base = base;
wasm.addGlobal(curr);
break;
}
default: {
throwError("bad import kind");
}
}
}
}
Name WasmBinaryBuilder::getNextLabel() {
requireFunctionContext("getting a label");
return Name("label$" + std::to_string(nextLabel++));
}
void WasmBinaryBuilder::requireFunctionContext(const char* error) {
if (!currFunction) {
throwError(std::string("in a non-function context: ") + error);
}
}
void WasmBinaryBuilder::readFunctionSignatures() {
if (debug) std::cerr << "== readFunctionSignatures" << std::endl;
size_t num = getU32LEB();
if (debug) std::cerr << "num: " << num << std::endl;
for (size_t i = 0; i < num; i++) {
if (debug) std::cerr << "read one" << std::endl;
auto index = getU32LEB();
if (index >= wasm.functionTypes.size()) {
throwError("invalid function type index for function");
}