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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 "wasm-emscripten.h"
#include "asm_v_wasm.h"
#include "asmjs/shared-constants.h"
#include "shared-constants.h"
#include "wasm-builder.h"
#include "wasm-traversal.h"
#include "wasm.h"
namespace wasm {
namespace emscripten {
cashew::IString EMSCRIPTEN_ASM_CONST("emscripten_asm_const");
void generateMemoryGrowthFunction(Module& wasm) {
Builder wasmBuilder(wasm);
Name name(GROW_WASM_MEMORY);
std::vector<NameType> params { { NEW_SIZE, i32 } };
Function* growFunction = wasmBuilder.makeFunction(
name, std::move(params), i32, {}
);
growFunction->body = wasmBuilder.makeHost(
GrowMemory,
Name(),
{ wasmBuilder.makeGetLocal(0, i32) }
);
wasm.addFunction(growFunction);
auto export_ = new Export;
export_->name = export_->value = name;
export_->kind = Export::Function;
wasm.addExport(export_);
}
static bool hasI64ResultOrParam(FunctionType* ft) {
if (ft->result == i64) return true;
for (auto ty : ft->params) {
if (ty == i64) return true;
}
return false;
}
std::vector<Function*> makeDynCallThunks(Module& wasm, std::vector<Name> const& tableSegmentData) {
wasm.removeImport(EMSCRIPTEN_ASM_CONST); // we create _sig versions
std::vector<Function*> generatedFunctions;
std::unordered_set<std::string> sigs;
Builder wasmBuilder(wasm);
for (const auto& indirectFunc : tableSegmentData) {
std::string sig(getSig(wasm.getFunction(indirectFunc)));
auto* funcType = ensureFunctionType(sig, &wasm);
if (hasI64ResultOrParam(funcType)) continue; // Can't export i64s on the web.
if (!sigs.insert(sig).second) continue; // Sig is already in the set
std::vector<NameType> params;
params.emplace_back("fptr", i32); // function pointer param
int p = 0;
for (const auto& ty : funcType->params) params.emplace_back(std::to_string(p++), ty);
Function* f = wasmBuilder.makeFunction(std::string("dynCall_") + sig, std::move(params), funcType->result, {});
Expression* fptr = wasmBuilder.makeGetLocal(0, i32);
std::vector<Expression*> args;
for (unsigned i = 0; i < funcType->params.size(); ++i) {
args.push_back(wasmBuilder.makeGetLocal(i + 1, funcType->params[i]));
}
Expression* call = wasmBuilder.makeCallIndirect(funcType, fptr, args);
f->body = call;
wasm.addFunction(f);
generatedFunctions.push_back(f);
}
return generatedFunctions;
}
struct AsmConstWalker : public PostWalker<AsmConstWalker, Visitor<AsmConstWalker>> {
Module& wasm;
std::unordered_map<Address, Address> segmentsByAddress; // address => segment index
std::map<std::string, std::set<std::string>> sigsForCode;
std::map<std::string, Address> ids;
std::set<std::string> allSigs;
AsmConstWalker(Module& _wasm, std::unordered_map<Address, Address> _segmentsByAddress) :
wasm(_wasm), segmentsByAddress(_segmentsByAddress) { }
void visitCallImport(CallImport* curr);
std::string escape(const char *input);
};
void AsmConstWalker::visitCallImport(CallImport* curr) {
if (curr->target == EMSCRIPTEN_ASM_CONST) {
auto arg = curr->operands[0]->cast<Const>();
auto address = arg->value.geti32();
auto segmentIterator = segmentsByAddress.find(address);
std::string code;
if (segmentIterator != segmentsByAddress.end()) {
Address segmentIndex = segmentsByAddress[address];
code = escape(&wasm.memory.segments[segmentIndex].data[0]);
} else {
// If we can't find the segment corresponding with the address, then we omitted the segment and the address points to an empty string.
code = escape("");
}
int32_t id;
if (ids.count(code) == 0) {
id = ids.size();
ids[code] = id;
} else {
id = ids[code];
}
std::string sig = getSig(curr);
sigsForCode[code].insert(sig);
std::string fixedTarget = EMSCRIPTEN_ASM_CONST.str + std::string("_") + sig;
curr->target = cashew::IString(fixedTarget.c_str(), false);
arg->value = Literal(id);
// add import, if necessary
if (allSigs.count(sig) == 0) {
allSigs.insert(sig);
auto import = new Import;
import->name = import->base = curr->target;
import->module = ENV;
import->functionType = ensureFunctionType(getSig(curr), &wasm);
import->kind = Import::Function;
wasm.addImport(import);
}
}
}
std::string AsmConstWalker::escape(const char *input) {
std::string code = input;
// replace newlines quotes with escaped newlines
size_t curr = 0;
while ((curr = code.find("\\n", curr)) != std::string::npos) {
code = code.replace(curr, 2, "\\\\n");
curr += 3; // skip this one
}
// replace double quotes with escaped single quotes
curr = 0;
while ((curr = code.find('"', curr)) != std::string::npos) {
if (curr == 0 || code[curr-1] != '\\') {
code = code.replace(curr, 1, "\\" "\"");
curr += 2; // skip this one
} else { // already escaped, escape the slash as well
code = code.replace(curr, 1, "\\" "\\" "\"");
curr += 3; // skip this one
}
}
return code;
}
template<class C>
void printSet(std::ostream& o, C& c) {
o << "[";
bool first = true;
for (auto& item : c) {
if (first) first = false;
else o << ",";
o << '"' << item << '"';
}
o << "]";
}
void generateEmscriptenMetadata(std::ostream& o,
Module& wasm,
std::unordered_map<Address, Address> segmentsByAddress,
Address staticBump,
std::vector<Name> const& initializerFunctions) {
o << ";; METADATA: { ";
// find asmConst calls, and emit their metadata
AsmConstWalker walker(wasm, segmentsByAddress);
walker.walkModule(&wasm);
// print
o << "\"asmConsts\": {";
bool first = true;
for (auto& pair : walker.sigsForCode) {
auto& code = pair.first;
auto& sigs = pair.second;
if (first) first = false;
else o << ",";
o << '"' << walker.ids[code] << "\": [\"" << code << "\", ";
printSet(o, sigs);
o << "]";
}
o << "}";
o << ",";
o << "\"staticBump\": " << staticBump << ", ";
o << "\"initializers\": [";
first = true;
for (const auto& func : initializerFunctions) {
if (first) first = false;
else o << ", ";
o << "\"" << func.c_str() << "\"";
}
o << "]";
o << " }\n";
}
} // namespace emscripten
} // namespace wasm
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