/*
* Copyright 2015 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.
*/
//
// WebAssembly-to-JS code translator. Converts wasm functions into
// valid JavaScript (with a somewhat asm.js-ish flavor).
//
#ifndef wasm_wasm2js_h
#define wasm_wasm2js_h
#include <cmath>
#include <numeric>
#include "abi/js.h"
#include "asm_v_wasm.h"
#include "asmjs/asmangle.h"
#include "asmjs/shared-constants.h"
#include "emscripten-optimizer/optimizer.h"
#include "ir/effects.h"
#include "ir/find_all.h"
#include "ir/import-utils.h"
#include "ir/load-utils.h"
#include "ir/module-utils.h"
#include "ir/names.h"
#include "ir/table-utils.h"
#include "ir/utils.h"
#include "mixed_arena.h"
#include "passes/passes.h"
#include "support/base64.h"
#include "wasm-builder.h"
#include "wasm-io.h"
#include "wasm-validator.h"
#include "wasm.h"
namespace wasm {
using namespace cashew;
IString ASM_FUNC("asmFunc");
IString ABORT_FUNC("abort");
IString FUNCTION_TABLE("FUNCTION_TABLE");
IString NO_RESULT("wasm2js$noresult"); // no result at all
// result in an expression, no temp var
IString EXPRESSION_RESULT("wasm2js$expresult");
// Appends extra to block, flattening out if extra is a block as well
void flattenAppend(Ref ast, Ref extra) {
int index;
if (ast[0] == BLOCK || ast[0] == TOPLEVEL) {
index = 1;
} else if (ast[0] == DEFUN) {
index = 3;
} else {
abort();
}
if (extra->isArray() && extra[0] == BLOCK) {
for (size_t i = 0; i < extra[1]->size(); i++) {
ast[index]->push_back(extra[1][i]);
}
} else {
ast[index]->push_back(extra);
}
}
// Appends extra to a chain of sequence elements
void sequenceAppend(Ref& ast, Ref extra) {
if (!ast.get()) {
ast = extra;
return;
}
ast = ValueBuilder::makeSeq(ast, extra);
}
IString stringToIString(std::string str) { return IString(str.c_str(), false); }
// Used when taking a wasm name and generating a JS identifier. Each scope here
// is used to ensure that all names have a unique name but the same wasm name
// within a scope always resolves to the same symbol.
enum class NameScope {
Top,
Local,
Label,
Max,
};
//
// Wasm2JSBuilder - converts a WebAssembly module's functions into JS
//
// In general, JS (asm.js) => wasm is very straightforward, as can
// be seen in asm2wasm.h. Just a single pass, plus a little
// state bookkeeping (breakStack, etc.), and a few after-the
// fact corrections for imports, etc. However, wasm => JS
// is tricky because wasm has statements == expressions, or in
// other words, things like `break` and `if` can show up
// in places where JS can't handle them, like inside an
// a loop's condition check. For that reason we use flat IR here.
// We do optimize it later, to allow some nesting, but we avoid
// non-JS-compatible nesting like block return values control
// flow in an if condition, etc.
//
class Wasm2JSBuilder {
MixedArena allocator;
public:
struct Flags {
bool debug = false;
bool pedantic = false;
bool allowAsserts = false;
bool emscripten = false;
};
Wasm2JSBuilder(Flags f, PassOptions options_) : flags(f), options(options_) {
// We don't try to model wasm's trapping precisely - if we did, each load
// and store would need to do a check. Given that, we can just ignore
// implicit traps like those when optimizing. (When not optimizing, it's
// nice to see codegen that matches wasm more precisely.)
if (options.optimizeLevel > 0) {
options.ignoreImplicitTraps = true;
}
}
Ref processWasm(Module* wasm, Name funcName = ASM_FUNC);
Ref processFunction(Module* wasm, Function* func, bool standalone = false);
Ref processStandaloneFunction(Module* wasm, Function* func) {
return processFunction(wasm, func, true);
}
// The second pass on an expression: process it fully, generating
// JS
Ref processFunctionBody(Module* m, Function* func, bool standalone);
// Get a temp var.
IString getTemp(Type type, Function* func) {
IString ret;
if (frees[type].size() > 0) {
ret = frees[type].back();
frees[type].pop_back();
} else {
size_t index = temps[type]++;
ret = IString((std::string("wasm2js_") + printType(type) + "$" +
std::to_string(index))
.c_str(),
false);
}
if (func->localIndices.find(ret) == func->localIndices.end()) {
Builder::addVar(func, ret, type);
}
return ret;
}
// Free a temp var.
void freeTemp(Type type, IString temp) { frees[type].push_back(temp); }
// Generates a mangled name from `name` within the specified scope.
//
// The goal of this function is to ensure that all identifiers in JS ar
// unique. Otherwise there can be clashes with locals and functions and cause
// unwanted name shadowing.
//
// The returned string from this function is constant for a particular `name`
// within a `scope`. Or in other words, the same `name` and `scope` pair will
// always return the same result. If `scope` changes, however, the return
// value may differ even if the same `name` is passed in.
IString fromName(Name name, NameScope scope) {
// TODO: checking names do not collide after mangling
// First up check our cached of mangled names to avoid doing extra work
// below
auto& mangledScope = mangledNames[(int)scope];
auto it = mangledScope.find(name.c_str());
if (it != mangledScope.end()) {
return it->second;
}
// This is the first time we've seen the `name` and `scope` pair. Generate a
// globally unique name based on `name` and then register that in our cache
// and return it.
//
// Identifiers here generated are of the form `${name}_${n}` where `_${n}`
// is omitted if `n==0` and otherwise `n` is just looped over to find the
// next unused identifier.
IString ret;
for (int i = 0;; i++) {
std::ostringstream out;
out << name.c_str();
if (i > 0) {
out << "_" << i;
}
auto mangled = asmangle(out.str());
ret = stringToIString(mangled);
if (!allMangledNames.count(ret)) {
break;
}
// In the global scope that's how you refer to actual function exports, so
// it's a bug currently if they're not globally unique. This should
// probably be fixed via a different namespace for exports or something
// like that.
// XXX This is not actually a valid check atm, since functions are not in
// the global-most scope, but rather in the "asmFunc" scope which is
// inside it. Also, for emscripten style glue, we emit the exports as
// a return, so there is no name placed into the scope. For these
// reasons, just warn here, don't error.
if (scope == NameScope::Top) {
std::cerr << "wasm2js: warning: global scope may be colliding with "
"other scope: "
<< mangled << '\n';
}
}
allMangledNames.insert(ret);
mangledScope[name.c_str()] = ret;
return ret;
}
private:
Flags flags;
PassOptions options;
// How many temp vars we need
std::vector<size_t> temps; // type => num temps
// Which are currently free to use
std::vector<std::vector<IString>> frees; // type => list of free names
// Mangled names cache by interned names.
// Utilizes the usually reused underlying cstring's pointer as the key.
std::unordered_map<const char*, IString> mangledNames[(int)NameScope::Max];
std::unordered_set<IString> allMangledNames;
// If a function is callable from outside, we'll need to cast the inputs
// and our return value. Otherwise, internally, casts are only needed
// on operations.
std::unordered_set<Name> functionsCallableFromOutside;
void addBasics(Ref ast);
void addFunctionImport(Ref ast, Function* import);
void addGlobalImport(Ref ast, Global* import);
void addTable(Ref ast, Module* wasm);
void addExports(Ref ast, Module* wasm);
void addGlobal(Ref ast, Global* global);
void addMemoryGrowthFuncs(Ref ast, Module* wasm);
Wasm2JSBuilder() = delete;
Wasm2JSBuilder(const Wasm2JSBuilder&) = delete;
Wasm2JSBuilder& operator=(const Wasm2JSBuilder&) = delete;
};
Ref Wasm2JSBuilder::processWasm(Module* wasm, Name funcName) {
// Scan the wasm for important things.
for (auto& exp : wasm->exports) {
if (exp->kind == ExternalKind::Function) {
functionsCallableFromOutside.insert(exp->value);
}
}
for (auto& segment : wasm->table.segments) {
for (auto name : segment.data) {
functionsCallableFromOutside.insert(name);
}
}
// Ensure the scratch memory helpers.
// If later on they aren't needed, we'll clean them up.
ABI::wasm2js::ensureScratchMemoryHelpers(wasm);
// Process the code, and optimize if relevant.
// First, do the lowering to a JS-friendly subset.
{
PassRunner runner(wasm, options);
runner.add<AutoDrop>();
runner.add("legalize-js-interface");
// First up remove as many non-JS operations we can, including things like
// 64-bit integer multiplication/division, `f32.nearest` instructions, etc.
// This may inject intrinsics which use i64 so it needs to be run before the
// i64-to-i32 lowering pass.
runner.add("remove-non-js-ops");
// Currently the i64-to-32 lowering pass requires that `flatten` be run
// before it to produce correct code. For some more details about this see
// #1480
runner.add("flatten");
runner.add("i64-to-i32-lowering");
runner.add("alignment-lowering");
// Next, optimize that as best we can. This should not generate
// non-JS-friendly things.
if (options.optimizeLevel > 0) {
// It is especially import to propagate constants after the lowering.
// However, this can be a slow operation, especially after flattening;
// some local simplification helps.
if (options.optimizeLevel >= 3 || options.shrinkLevel >= 1) {
runner.add("simplify-locals-nonesting");
runner.add("precompute-propagate");
// Avoiding reinterpretation is helped by propagation. We also run
// it later down as default optimizations help as well.
runner.add("avoid-reinterprets");
}
runner.addDefaultOptimizationPasses();
runner.add("avoid-reinterprets");
}
// Finally, get the code into the flat form we need for wasm2js itself, and
// optimize that a little in a way that keeps flat property.
runner.add("flatten");
// Regardless of optimization level, run some simple optimizations to undo
// some of the effects of flattening.
runner.add("simplify-locals-notee-nostructure");
// Some operations can be very slow if we didn't run full optimizations
// earlier, so don't run them automatically.
if (options.optimizeLevel > 0) {
runner.add("remove-unused-names");
runner.add("merge-blocks");
runner.add("coalesce-locals");
}
runner.add("reorder-locals");
runner.add("vacuum");
runner.add("remove-unused-module-elements");
runner.setDebug(flags.debug);
runner.run();
}
#ifndef NDEBUG
if (!WasmValidator().validate(*wasm)) {
WasmPrinter::printModule(wasm);
Fatal() << "error in validating wasm2js output";
}
#endif
Ref ret = ValueBuilder::makeToplevel();
Ref asmFunc = ValueBuilder::makeFunction(funcName);
ret[1]->push_back(asmFunc);
ValueBuilder::appendArgumentToFunction(asmFunc, GLOBAL);
ValueBuilder::appendArgumentToFunction(asmFunc, ENV);
ValueBuilder::appendArgumentToFunction(asmFunc, BUFFER);
asmFunc[3]->push_back(
ValueBuilder::makeStatement(ValueBuilder::makeString(ALMOST_ASM)));
// add memory import
if (wasm->memory.exists && wasm->memory.imported()) {
Ref theVar = ValueBuilder::makeVar();
asmFunc[3]->push_back(theVar);
ValueBuilder::appendToVar(
theVar,
"memory",
ValueBuilder::makeDot(ValueBuilder::makeName(ENV),
ValueBuilder::makeName("memory")));
}
// for emscripten, add a table import - otherwise we would have
// FUNCTION_TABLE be an upvar, and not as easy to be minified.
if (flags.emscripten && wasm->table.exists && wasm->table.imported()) {
Ref theVar = ValueBuilder::makeVar();
asmFunc[3]->push_back(theVar);
ValueBuilder::appendToVar(
theVar, FUNCTION_TABLE, ValueBuilder::makeName("wasmTable"));
}
// create heaps, etc
addBasics(asmFunc[3]);
ModuleUtils::iterImportedFunctions(
*wasm, [&](Function* import) { addFunctionImport(asmFunc[3], import); });
ModuleUtils::iterImportedGlobals(
*wasm, [&](Global* import) { addGlobalImport(asmFunc[3], import); });
// make sure exports get their expected names
for (auto& e : wasm->exports) {
if (e->kind == ExternalKind::Function) {
fromName(e->name, NameScope::Top);
}
}
for (auto& f : wasm->functions) {
fromName(f->name, NameScope::Top);
}
fromName(WASM_FETCH_HIGH_BITS, NameScope::Top);
// globals
bool generateFetchHighBits = false;
ModuleUtils::iterDefinedGlobals(*wasm, [&](Global* global) {
addGlobal(asmFunc[3], global);
if (flags.allowAsserts && global->name == INT64_TO_32_HIGH_BITS) {
generateFetchHighBits = true;
}
});
if (flags.emscripten) {
asmFunc[3]->push_back(ValueBuilder::makeName("// EMSCRIPTEN_START_FUNCS"));
}
// functions
ModuleUtils::iterDefinedFunctions(*wasm, [&](Function* func) {
asmFunc[3]->push_back(processFunction(wasm, func));
});
if (generateFetchHighBits) {
Builder builder(allocator);
std::vector<Type> params;
std::vector<Type> vars;
asmFunc[3]->push_back(processFunction(
wasm,
builder.makeFunction(WASM_FETCH_HIGH_BITS,
std::move(params),
i32,
std::move(vars),
builder.makeReturn(builder.makeGlobalGet(
INT64_TO_32_HIGH_BITS, i32)))));
auto e = new Export();
e->name = WASM_FETCH_HIGH_BITS;
e->value = WASM_FETCH_HIGH_BITS;
e->kind = ExternalKind::Function;
wasm->addExport(e);
}
if (flags.emscripten) {
asmFunc[3]->push_back(ValueBuilder::makeName("// EMSCRIPTEN_END_FUNCS"));
}
addTable(asmFunc[3], wasm);
// memory XXX
addExports(asmFunc[3], wasm);
return ret;
}
void Wasm2JSBuilder::addBasics(Ref ast) {
// heaps, var HEAP8 = new global.Int8Array(buffer); etc
auto addHeap = [&](IString name, IString view) {
Ref theVar = ValueBuilder::makeVar();
ast->push_back(theVar);
ValueBuilder::appendToVar(
theVar,
name,
ValueBuilder::makeNew(ValueBuilder::makeCall(
ValueBuilder::makeDot(ValueBuilder::makeName(GLOBAL), view),
ValueBuilder::makeName(BUFFER))));
};
addHeap(HEAP8, INT8ARRAY);
addHeap(HEAP16, INT16ARRAY);
addHeap(HEAP32, INT32ARRAY);
addHeap(HEAPU8, UINT8ARRAY);
addHeap(HEAPU16, UINT16ARRAY);
addHeap(HEAPU32, UINT32ARRAY);
addHeap(HEAPF32, FLOAT32ARRAY);
addHeap(HEAPF64, FLOAT64ARRAY);
// core asm.js imports
auto addMath = [&](IString name, IString base) {
Ref theVar = ValueBuilder::makeVar();
ast->push_back(theVar);
ValueBuilder::appendToVar(
theVar,
name,
ValueBuilder::makeDot(
ValueBuilder::makeDot(ValueBuilder::makeName(GLOBAL), MATH), base));
};
addMath(MATH_IMUL, IMUL);
addMath(MATH_FROUND, FROUND);
addMath(MATH_ABS, ABS);
addMath(MATH_CLZ32, CLZ32);
addMath(MATH_MIN, MIN);
addMath(MATH_MAX, MAX);
addMath(MATH_FLOOR, FLOOR);
addMath(MATH_CEIL, CEIL);
addMath(MATH_SQRT, SQRT);
// abort function
Ref abortVar = ValueBuilder::makeVar();
ast->push_back(abortVar);
ValueBuilder::appendToVar(
abortVar,
"abort",
ValueBuilder::makeDot(ValueBuilder::makeName(ENV), ABORT_FUNC));
// TODO: this shouldn't be needed once we stop generating literal asm.js code
// NaN and Infinity variables
Ref nanVar = ValueBuilder::makeVar();
ast->push_back(nanVar);
ValueBuilder::appendToVar(
nanVar,
"nan",
ValueBuilder::makeDot(ValueBuilder::makeName(GLOBAL), "NaN"));
Ref infinityVar = ValueBuilder::makeVar();
ast->push_back(infinityVar);
ValueBuilder::appendToVar(
infinityVar,
"infinity",
ValueBuilder::makeDot(ValueBuilder::makeName(GLOBAL), "Infinity"));
}
void Wasm2JSBuilder::addFunctionImport(Ref ast, Function* import) {
// The scratch memory helpers are emitted in the glue, see code and comments
// below.
if (ABI::wasm2js::isScratchMemoryHelper(import->base)) {
return;
}
Ref theVar = ValueBuilder::makeVar();
ast->push_back(theVar);
// TODO: handle nested module imports
Ref module = ValueBuilder::makeName(ENV);
ValueBuilder::appendToVar(
theVar,
fromName(import->name, NameScope::Top),
ValueBuilder::makeDot(module, fromName(import->base, NameScope::Top)));
}
void Wasm2JSBuilder::addGlobalImport(Ref ast, Global* import) {
Ref theVar = ValueBuilder::makeVar();
ast->push_back(theVar);
// TODO: handle nested module imports
Ref module = ValueBuilder::makeName(ENV);
Ref value =
ValueBuilder::makeDot(module, fromName(import->base, NameScope::Top));
if (import->type == i32) {
value = makeAsmCoercion(value, ASM_INT);
}
ValueBuilder::appendToVar(
theVar, fromName(import->name, NameScope::Top), value);
}
void Wasm2JSBuilder::addTable(Ref ast, Module* wasm) {
// Emit a simple flat table as a JS array literal. Otherwise,
// emit assignments separately for each index.
FlatTable flat(wasm->table);
if (flat.valid && !wasm->table.imported()) {
Ref theVar = ValueBuilder::makeVar();
ast->push_back(theVar);
Ref theArray = ValueBuilder::makeArray();
ValueBuilder::appendToVar(theVar, FUNCTION_TABLE, theArray);
Name null("null");
for (auto& name : flat.names) {
if (name.is()) {
name = fromName(name, NameScope::Top);
} else {
name = null;
}
ValueBuilder::appendToArray(theArray, ValueBuilder::makeName(name));
}
} else {
if (!wasm->table.imported()) {
Ref theVar = ValueBuilder::makeVar();
ast->push_back(theVar);
ValueBuilder::appendToVar(
theVar, FUNCTION_TABLE, ValueBuilder::makeArray());
}
// TODO: optimize for size
for (auto& segment : wasm->table.segments) {
auto offset = segment.offset;
for (Index i = 0; i < segment.data.size(); i++) {
Ref index;
if (auto* c = offset->dynCast<Const>()) {
index = ValueBuilder::makeInt(c->value.geti32() + i);
} else if (auto* get = offset->dynCast<GlobalGet>()) {
index = ValueBuilder::makeBinary(
ValueBuilder::makeName(stringToIString(asmangle(get->name.str))),
PLUS,
ValueBuilder::makeNum(i));
} else {
WASM_UNREACHABLE();
}
ast->push_back(ValueBuilder::makeStatement(ValueBuilder::makeBinary(
ValueBuilder::makeSub(ValueBuilder::makeName(FUNCTION_TABLE), index),
SET,
ValueBuilder::makeName(fromName(segment.data[i], NameScope::Top)))));
}
}
}
}
void Wasm2JSBuilder::addExports(Ref ast, Module* wasm) {
Ref exports = ValueBuilder::makeObject();
for (auto& export_ : wasm->exports) {
if (export_->kind == ExternalKind::Function) {
ValueBuilder::appendToObjectWithQuotes(
exports,
fromName(export_->name, NameScope::Top),
ValueBuilder::makeName(fromName(export_->value, NameScope::Top)));
}
if (export_->kind == ExternalKind::Memory) {
Ref descs = ValueBuilder::makeObject();
Ref growDesc = ValueBuilder::makeObject();
ValueBuilder::appendToObjectWithQuotes(descs, IString("grow"), growDesc);
ValueBuilder::appendToObjectWithQuotes(
growDesc, IString("value"), ValueBuilder::makeName(WASM_MEMORY_GROW));
Ref bufferDesc = ValueBuilder::makeObject();
Ref bufferGetter = ValueBuilder::makeFunction(IString(""));
bufferGetter[3]->push_back(
ValueBuilder::makeReturn(ValueBuilder::makeName(BUFFER)));
ValueBuilder::appendToObjectWithQuotes(
bufferDesc, IString("get"), bufferGetter);
ValueBuilder::appendToObjectWithQuotes(
descs, IString("buffer"), bufferDesc);
Ref memory = ValueBuilder::makeCall(
ValueBuilder::makeDot(ValueBuilder::makeName(IString("Object")),
IString("create")),
ValueBuilder::makeDot(ValueBuilder::makeName(IString("Object")),
IString("prototype")));
ValueBuilder::appendToCall(memory, descs);
ValueBuilder::appendToObjectWithQuotes(
exports, fromName(export_->name, NameScope::Top), memory);
}
}
if (wasm->memory.exists && wasm->memory.max > wasm->memory.initial) {
addMemoryGrowthFuncs(ast, wasm);
}
ast->push_back(
ValueBuilder::makeStatement(ValueBuilder::makeReturn(exports)));
}
void Wasm2JSBuilder::addGlobal(Ref ast, Global* global) {
if (auto* const_ = global->init->dynCast<Const>()) {
Ref theValue;
switch (const_->type) {
case Type::i32: {
theValue = ValueBuilder::makeInt(const_->value.geti32());
break;
}
case Type::f32: {
theValue = ValueBuilder::makeCall(
MATH_FROUND,
makeAsmCoercion(ValueBuilder::makeDouble(const_->value.getf32()),
ASM_DOUBLE));
break;
}
case Type::f64: {
theValue = makeAsmCoercion(
ValueBuilder::makeDouble(const_->value.getf64()), ASM_DOUBLE);
break;
}
default: { assert(false && "Top const type not supported"); }
}
Ref theVar = ValueBuilder::makeVar();
ast->push_back(theVar);
ValueBuilder::appendToVar(
theVar, fromName(global->name, NameScope::Top), theValue);
} else if (auto* get = global->init->dynCast<GlobalGet>()) {
Ref theVar = ValueBuilder::makeVar();
ast->push_back(theVar);
ValueBuilder::appendToVar(
theVar,
fromName(global->name, NameScope::Top),
ValueBuilder::makeName(fromName(get->name, NameScope::Top)));
} else {
assert(false && "Top init type not supported");
}
}
Ref Wasm2JSBuilder::processFunction(Module* m,
Function* func,
bool standaloneFunction) {
if (standaloneFunction) {
// We are only printing a function, not a whole module. Prepare it for
// translation now (if there were a module, we'd have done this for all
// functions in parallel, earlier).
PassRunner runner(m);
// We only run a subset of all passes here. TODO: create a full valid module
// for each assertion body.
runner.add("flatten");
runner.add("simplify-locals-notee-nostructure");
runner.add("reorder-locals");
runner.add("remove-unused-names");
runner.add("vacuum");
runner.runOnFunction(func);
}
// We will be symbolically referring to all variables in the function, so make
// sure that everything has a name and it's unique.
Names::ensureNames(func);
Ref ret = ValueBuilder::makeFunction(fromName(func->name, NameScope::Top));
frees.clear();
frees.resize(std::max(i32, std::max(f32, f64)) + 1);
temps.clear();
temps.resize(std::max(i32, std::max(f32, f64)) + 1);
temps[i32] = temps[f32] = temps[f64] = 0;
// arguments
bool needCoercions = options.optimizeLevel == 0 || standaloneFunction ||
functionsCallableFromOutside.count(func->name);
for (Index i = 0; i < func->getNumParams(); i++) {
IString name = fromName(func->getLocalNameOrGeneric(i), NameScope::Local);
ValueBuilder::appendArgumentToFunction(ret, name);
if (needCoercions) {
ret[3]->push_back(ValueBuilder::makeStatement(ValueBuilder::makeBinary(
ValueBuilder::makeName(name),
SET,
makeAsmCoercion(ValueBuilder::makeName(name),
wasmToAsmType(func->getLocalType(i))))));
}
}
Ref theVar = ValueBuilder::makeVar();
size_t theVarIndex = ret[3]->size();
ret[3]->push_back(theVar);
// body
flattenAppend(ret, processFunctionBody(m, func, standaloneFunction));
// vars, including new temp vars
for (Index i = func->getVarIndexBase(); i < func->getNumLocals(); i++) {
ValueBuilder::appendToVar(
theVar,
fromName(func->getLocalNameOrGeneric(i), NameScope::Local),
makeAsmCoercedZero(wasmToAsmType(func->getLocalType(i))));
}
if (theVar[1]->size() == 0) {
ret[3]->splice(theVarIndex, 1);
}
// checks: all temp vars should be free at the end
assert(frees[i32].size() == temps[i32]);
assert(frees[f32].size() == temps[f32]);
assert(frees[f64].size() == temps[f64]);
return ret;
}
Ref Wasm2JSBuilder::processFunctionBody(Module* m,
Function* func,
bool standaloneFunction) {
struct ExpressionProcessor : public Visitor<ExpressionProcessor, Ref> {
Wasm2JSBuilder* parent;
IString result; // TODO: remove
Function* func;
Module* module;
bool standaloneFunction;
MixedArena allocator;
ExpressionProcessor(Wasm2JSBuilder* parent,
Module* m,
Function* func,
bool standaloneFunction)
: parent(parent), func(func), module(m),
standaloneFunction(standaloneFunction) {}
// A scoped temporary variable.
struct ScopedTemp {
Wasm2JSBuilder* parent;
Type type;
IString temp; // TODO: switch to indexes; avoid names
bool needFree;
// @param possible if provided, this is a variable we can use as our temp.
// it has already been allocated in a higher scope, and we
// can just assign to it as our result is going there
// anyhow.
ScopedTemp(Type type,
Wasm2JSBuilder* parent,
Function* func,
IString possible = NO_RESULT)
: parent(parent), type(type) {
assert(possible != EXPRESSION_RESULT);
if (possible == NO_RESULT) {
temp = parent->getTemp(type, func);
needFree = true;
} else {
temp = possible;
needFree = false;
}
}
~ScopedTemp() {
if (needFree) {
parent->freeTemp(type, temp);
}
}
IString getName() { return temp; }
Ref getAstName() { return ValueBuilder::makeName(temp); }
};
Ref visit(Expression* curr, IString nextResult) {
IString old = result;
result = nextResult;
Ref ret = Visitor::visit(curr);
// keep it consistent for the rest of this frame, which may call visit on
// multiple children
result = old;
return ret;
}
Ref visit(Expression* curr, ScopedTemp& temp) {
return visit(curr, temp.temp);
}
Ref visitAndAssign(Expression* curr, IString result) {
assert(result != NO_RESULT);
Ref ret = visit(curr, result);
return ValueBuilder::makeStatement(
ValueBuilder::makeBinary(ValueBuilder::makeName(result), SET, ret));
}
Ref visitAndAssign(Expression* curr, ScopedTemp& temp) {
return visitAndAssign(curr, temp.getName());
}
// Expressions with control flow turn into a block, which we must
// then handle, even if we are an expression.
bool isBlock(Ref ast) { return !!ast && ast->isArray() && ast[0] == BLOCK; }
Ref blockify(Ref ast) {
if (isBlock(ast)) {
return ast;
}
Ref ret = ValueBuilder::makeBlock();
ret[1]->push_back(ValueBuilder::makeStatement(ast));
return ret;
}
// Breaks to the top of a loop should be emitted as continues, to that
// loop's main label
std::unordered_set<Name> continueLabels;
IString fromName(Name name, NameScope scope) {
return parent->fromName(name, scope);
}
// Visitors
Ref visitBlock(Block* curr) {
Ref ret = ValueBuilder::makeBlock();
size_t size = curr->list.size();
auto noResults = result == NO_RESULT ? size : size - 1;
for (size_t i = 0; i < noResults; i++) {
flattenAppend(
ret, ValueBuilder::makeStatement(visit(curr->list[i], NO_RESULT)));
}
if (result != NO_RESULT) {
flattenAppend(ret, visitAndAssign(curr->list[size - 1], result));
}
if (curr->name.is()) {
ret =
ValueBuilder::makeLabel(fromName(curr->name, NameScope::Label), ret);
}
return ret;
}
Ref visitIf(If* curr) {
Ref condition = visit(curr->condition, EXPRESSION_RESULT);
Ref ifTrue = visit(curr->ifTrue, NO_RESULT);
Ref ifFalse;
if (curr->ifFalse) {
ifFalse = visit(curr->ifFalse, NO_RESULT);
}
return ValueBuilder::makeIf(condition, ifTrue, ifFalse); // simple if
}
Ref visitLoop(Loop* curr) {
Name asmLabel = curr->name;
continueLabels.insert(asmLabel);
Ref body = visit(curr->body, result);
// if we can reach the end of the block, we must leave the while (1) loop
if (curr->body->type != unreachable) {
assert(curr->body->type == none); // flat IR
body = blockify(body);
flattenAppend(
body, ValueBuilder::makeBreak(fromName(asmLabel, NameScope::Label)));
}
Ref ret = ValueBuilder::makeWhile(ValueBuilder::makeInt(1), body);
return ValueBuilder::makeLabel(fromName(asmLabel, NameScope::Label), ret);
}
Ref makeBreakOrContinue(Name name) {
if (continueLabels.count(name)) {
return ValueBuilder::makeContinue(fromName(name, NameScope::Label));
} else {
return ValueBuilder::makeBreak(fromName(name, NameScope::Label));
}
}
Ref visitBreak(Break* curr) {
if (curr->condition) {
// we need an equivalent to an if here, so use that code
Break fakeBreak = *curr;
fakeBreak.condition = nullptr;
If fakeIf(allocator);
fakeIf.condition = curr->condition;
fakeIf.ifTrue = &fakeBreak;
return visit(&fakeIf, result);
}
return makeBreakOrContinue(curr->name);
}
Expression* defaultBody = nullptr; // default must be last in asm.js
Ref visitSwitch(Switch* curr) {
assert(!curr->value);
Ref ret = ValueBuilder::makeBlock();
Ref condition = visit(curr->condition, EXPRESSION_RESULT);
Ref theSwitch =
ValueBuilder::makeSwitch(makeAsmCoercion(condition, ASM_INT));
ret[1]->push_back(theSwitch);
// First, group the switch targets.
std::map<Name, std::vector<Index>> targetIndexes;
for (size_t i = 0; i < curr->targets.size(); i++) {
targetIndexes[curr->targets[i]].push_back(i);
}
// Emit group by group.
for (auto& pair : targetIndexes) {
auto target = pair.first;
auto& indexes = pair.second;
if (target != curr->default_) {
for (auto i : indexes) {
ValueBuilder::appendCaseToSwitch(theSwitch,
ValueBuilder::makeNum(i));
}
ValueBuilder::appendCodeToSwitch(
theSwitch, blockify(makeBreakOrContinue(target)), false);
} else {
// For the group going to the same place as the default, we can just
// emit the default itself, which we do at the end.
}
}
// TODO: if the group the default is in is not the largest, we can turn
// the largest into
// the default by using a local and a check on the range
ValueBuilder::appendDefaultToSwitch(theSwitch);
ValueBuilder::appendCodeToSwitch(
theSwitch, blockify(makeBreakOrContinue(curr->default_)), false);
return ret;
}
Ref visitCall(Call* curr) {
Ref theCall =
ValueBuilder::makeCall(fromName(curr->target, NameScope::Top));
// For wasm => wasm calls, we don't need coercions. TODO: even imports
// might be safe?
bool needCoercions = parent->options.optimizeLevel == 0 ||
standaloneFunction ||
module->getFunction(curr->target)->imported();
for (auto operand : curr->operands) {
auto value = visit(operand, EXPRESSION_RESULT);
if (needCoercions) {
value = makeAsmCoercion(value, wasmToAsmType(operand->type));
}
theCall[2]->push_back(value);
}
if (needCoercions) {
theCall = makeAsmCoercion(theCall, wasmToAsmType(curr->type));
}
return theCall;
}
Ref visitCallIndirect(CallIndirect* curr) {
// If the target has effects that interact with the operands, we must
// reorder it to the start.
bool mustReorder = false;
EffectAnalyzer targetEffects(parent->options, curr->target);
if (targetEffects.hasAnything()) {
for (auto* operand : curr->operands) {
if (targetEffects.invalidates(
EffectAnalyzer(parent->options, operand))) {
mustReorder = true;
break;
}
}
}
if (mustReorder) {
Ref ret;
ScopedTemp idx(i32, parent, func);
std::vector<ScopedTemp*> temps; // TODO: utility class, with destructor?
for (auto* operand : curr->operands) {
temps.push_back(new ScopedTemp(operand->type, parent, func));
IString temp = temps.back()->temp;
sequenceAppend(ret, visitAndAssign(operand, temp));
}
sequenceAppend(ret, visitAndAssign(curr->target, idx));
Ref theCall = ValueBuilder::makeCall(ValueBuilder::makeSub(
ValueBuilder::makeName(FUNCTION_TABLE), idx.getAstName()));
for (size_t i = 0; i < temps.size(); i++) {
IString temp = temps[i]->temp;
auto& operand = curr->operands[i];
theCall[2]->push_back(makeAsmCoercion(ValueBuilder::makeName(temp),
wasmToAsmType(operand->type)));
}
theCall = makeAsmCoercion(theCall, wasmToAsmType(curr->type));
sequenceAppend(ret, theCall);
for (auto temp : temps) {
delete temp;
}
return ret;
} else {
// Target has no side effects, emit simple code
Ref theCall = ValueBuilder::makeCall(
ValueBuilder::makeSub(ValueBuilder::makeName(FUNCTION_TABLE),
visit(curr->target, EXPRESSION_RESULT)));
for (auto* operand : curr->operands) {
theCall[2]->push_back(visit(operand, EXPRESSION_RESULT));
}
theCall = makeAsmCoercion(theCall, wasmToAsmType(curr->type));
return theCall;
}
}
// TODO: remove
Ref makeSetVar(Expression* curr,
Expression* value,
Name name,
NameScope scope) {
return ValueBuilder::makeBinary(
ValueBuilder::makeName(fromName(name, scope)),
SET,
visit(value, EXPRESSION_RESULT));
}
Ref visitLocalGet(LocalGet* curr) {
return ValueBuilder::makeName(
fromName(func->getLocalNameOrGeneric(curr->index), NameScope::Local));
}
Ref visitLocalSet(LocalSet* curr) {
return makeSetVar(curr,
curr->value,
func->getLocalNameOrGeneric(curr->index),
NameScope::Local);
}
Ref visitGlobalGet(GlobalGet* curr) {
return ValueBuilder::makeName(fromName(curr->name, NameScope::Top));
}
Ref visitGlobalSet(GlobalSet* curr) {
return makeSetVar(curr, curr->value, curr->name, NameScope::Top);
}
Ref visitLoad(Load* curr) {
// Unaligned loads and stores must have been fixed up already.
assert(curr->align == 0 || curr->align == curr->bytes);
// normal load
Ref ptr = makePointer(curr->ptr, curr->offset);
Ref ret;
switch (curr->type) {
case i32: {
switch (curr->bytes) {
case 1:
ret = ValueBuilder::makeSub(
ValueBuilder::makeName(
LoadUtils::isSignRelevant(curr) && curr->signed_ ? HEAP8
: HEAPU8),
ValueBuilder::makePtrShift(ptr, 0));
break;
case 2:
ret = ValueBuilder::makeSub(
ValueBuilder::makeName(
LoadUtils::isSignRelevant(curr) && curr->signed_ ? HEAP16
: HEAPU16),
ValueBuilder::makePtrShift(ptr, 1));
break;
case 4:
ret = ValueBuilder::makeSub(ValueBuilder::makeName(HEAP32),
ValueBuilder::makePtrShift(ptr, 2));
break;
default: {
std::cerr << "Unhandled number of bytes in i32 load: "
<< curr->bytes << std::endl;
abort();
}
}
break;
}
case f32:
ret = ValueBuilder::makeSub(ValueBuilder::makeName(HEAPF32),
ValueBuilder::makePtrShift(ptr, 2));
break;
case f64:
ret = ValueBuilder::makeSub(ValueBuilder::makeName(HEAPF64),
ValueBuilder::makePtrShift(ptr, 3));
break;
default: {
std::cerr << "Unhandled type in load: " << curr->type << std::endl;
abort();
}
}
// Coercions are not actually needed, as if the user reads beyond valid
// memory, it's undefined behavior anyhow, and so we don't care much about
// slowness of undefined values etc.
bool needCoercions =
parent->options.optimizeLevel == 0 || standaloneFunction;
if (needCoercions) {
ret = makeAsmCoercion(ret, wasmToAsmType(curr->type));
}
return ret;
}
Ref visitStore(Store* curr) {
if (module->memory.initial < module->memory.max &&
curr->type != unreachable) {
// In JS, if memory grows then it is dangerous to write
// HEAP[f()] = ..
// or
// HEAP[..] = f()
// since if the call swaps HEAP (in a growth operation) then
// we will not actually write to the new version (since the
// semantics of JS mean we already looked at HEAP and have
// decided where to assign to).
if (!FindAll<Call>(curr->ptr).list.empty() ||
!FindAll<Call>(curr->value).list.empty() ||
!FindAll<CallIndirect>(curr->ptr).list.empty() ||
!FindAll<CallIndirect>(curr->value).list.empty() ||
!FindAll<Host>(curr->ptr).list.empty() ||
!FindAll<Host>(curr->value).list.empty()) {
Ref ret;
ScopedTemp ptr(i32, parent, func);
sequenceAppend(ret, visitAndAssign(curr->ptr, ptr));
ScopedTemp value(curr->value->type, parent, func);
sequenceAppend(ret, visitAndAssign(curr->value, value));
LocalGet getPtr;
getPtr.index = func->getLocalIndex(ptr.getName());
getPtr.type = i32;
LocalGet getValue;
getValue.index = func->getLocalIndex(value.getName());
getValue.type = curr->value->type;
Store fakeStore = *curr;
fakeStore.ptr = &getPtr;
fakeStore.value = &getValue;
sequenceAppend(ret, visitStore(&fakeStore));
return ret;
}
}
// FIXME if memory growth, store ptr cannot contain a function call
// also other stores to memory, check them, all makeSub's
// Unaligned loads and stores must have been fixed up already.
assert(curr->align == 0 || curr->align == curr->bytes);
// normal store
Ref ptr = makePointer(curr->ptr, curr->offset);
Ref value = visit(curr->value, EXPRESSION_RESULT);
Ref ret;
switch (curr->valueType) {
case i32: {
switch (curr->bytes) {
case 1:
ret = ValueBuilder::makeSub(ValueBuilder::makeName(HEAP8),
ValueBuilder::makePtrShift(ptr, 0));
break;
case 2:
ret = ValueBuilder::makeSub(ValueBuilder::makeName(HEAP16),
ValueBuilder::makePtrShift(ptr, 1));
break;
case 4:
ret = ValueBuilder::makeSub(ValueBuilder::makeName(HEAP32),
ValueBuilder::makePtrShift(ptr, 2));
break;
default:
abort();
}
break;
}
case f32:
ret = ValueBuilder::makeSub(ValueBuilder::makeName(HEAPF32),
ValueBuilder::makePtrShift(ptr, 2));
break;
case f64:
ret = ValueBuilder::makeSub(ValueBuilder::makeName(HEAPF64),
ValueBuilder::makePtrShift(ptr, 3));
break;
default: {
std::cerr << "Unhandled type in store: " << curr->valueType
<< std::endl;
abort();
}
}
return ValueBuilder::makeBinary(ret, SET, value);
}
Ref visitDrop(Drop* curr) { return visit(curr->value, NO_RESULT); }
Ref visitConst(Const* curr) {
switch (curr->type) {
case i32:
return ValueBuilder::makeInt(curr->value.geti32());
// An i64 argument translates to two actual arguments to asm.js
// functions, so we do a bit of a hack here to get our one `Ref` to look
// like two function arguments.
case i64: {
auto lo = (unsigned)curr->value.geti64();
auto hi = (unsigned)(curr->value.geti64() >> 32);
std::ostringstream out;
out << lo << "," << hi;
std::string os = out.str();
IString name(os.c_str(), false);
return ValueBuilder::makeName(name);
}
case f32: {
Ref ret = ValueBuilder::makeCall(MATH_FROUND);
Const fake(allocator);
fake.value = Literal(double(curr->value.getf32()));
fake.type = f64;
ret[2]->push_back(visitConst(&fake));
return ret;
}
case f64: {
double d = curr->value.getf64();
if (d == 0 && std::signbit(d)) { // negative zero
return ValueBuilder::makeUnary(
PLUS,
ValueBuilder::makeUnary(MINUS, ValueBuilder::makeDouble(0)));
}
return ValueBuilder::makeUnary(
PLUS, ValueBuilder::makeDouble(curr->value.getf64()));
}
default:
abort();
}
}
Ref visitUnary(Unary* curr) {
// normal unary
switch (curr->type) {
case i32: {
switch (curr->op) {
case ClzInt32: {
return ValueBuilder::makeCall(
MATH_CLZ32, visit(curr->value, EXPRESSION_RESULT));
}
case CtzInt32:
case PopcntInt32: {
std::cerr << "i32 unary should have been removed: " << curr
<< std::endl;
WASM_UNREACHABLE();
}
case EqZInt32: {
// XXX !x does change the type to bool, which is correct, but may
// be slower?
return ValueBuilder::makeUnary(
L_NOT, visit(curr->value, EXPRESSION_RESULT));
}
case ReinterpretFloat32: {
ABI::wasm2js::ensureScratchMemoryHelpers(
module, ABI::wasm2js::SCRATCH_STORE_F32);
ABI::wasm2js::ensureScratchMemoryHelpers(
module, ABI::wasm2js::SCRATCH_LOAD_I32);
Ref store =
ValueBuilder::makeCall(ABI::wasm2js::SCRATCH_STORE_F32,
visit(curr->value, EXPRESSION_RESULT));
Ref load = ValueBuilder::makeCall(ABI::wasm2js::SCRATCH_LOAD_I32,
ValueBuilder::makeInt(0));
return ValueBuilder::makeSeq(store, load);
}
// generate (~~expr), what Emscripten does
case TruncSFloat32ToInt32:
case TruncSFloat64ToInt32:
case TruncSatSFloat32ToInt32:
case TruncSatSFloat64ToInt32: {
return ValueBuilder::makeUnary(
B_NOT,
ValueBuilder::makeUnary(B_NOT,
visit(curr->value, EXPRESSION_RESULT)));
}
// generate (~~expr >>> 0), what Emscripten does
case TruncUFloat32ToInt32:
case TruncUFloat64ToInt32:
case TruncSatUFloat32ToInt32:
case TruncSatUFloat64ToInt32: {
return ValueBuilder::makeBinary(
ValueBuilder::makeUnary(
B_NOT,
ValueBuilder::makeUnary(
B_NOT, visit(curr->value, EXPRESSION_RESULT))),
TRSHIFT,
ValueBuilder::makeNum(0));
}
default: {
std::cerr << "Unhandled unary i32 operator: " << curr
<< std::endl;
abort();
}
}
}
case f32:
case f64: {
Ref ret;
switch (curr->op) {
case NegFloat32:
case NegFloat64:
ret = ValueBuilder::makeUnary(
MINUS, visit(curr->value, EXPRESSION_RESULT));
break;
case AbsFloat32:
case AbsFloat64:
ret = ValueBuilder::makeCall(
MATH_ABS, visit(curr->value, EXPRESSION_RESULT));
break;
case CeilFloat32:
case CeilFloat64:
ret = ValueBuilder::makeCall(
MATH_CEIL, visit(curr->value, EXPRESSION_RESULT));
break;
case FloorFloat32:
case FloorFloat64:
ret = ValueBuilder::makeCall(
MATH_FLOOR, visit(curr->value, EXPRESSION_RESULT));
break;
case SqrtFloat32:
case SqrtFloat64:
ret = ValueBuilder::makeCall(
MATH_SQRT, visit(curr->value, EXPRESSION_RESULT));
break;
case PromoteFloat32:
return makeAsmCoercion(visit(curr->value, EXPRESSION_RESULT),
ASM_DOUBLE);
case DemoteFloat64:
return makeAsmCoercion(visit(curr->value, EXPRESSION_RESULT),
ASM_FLOAT);
case ReinterpretInt32: {
ABI::wasm2js::ensureScratchMemoryHelpers(
module, ABI::wasm2js::SCRATCH_STORE_I32);
ABI::wasm2js::ensureScratchMemoryHelpers(
module, ABI::wasm2js::SCRATCH_LOAD_F32);
Ref store =
ValueBuilder::makeCall(ABI::wasm2js::SCRATCH_STORE_I32,
ValueBuilder::makeNum(0),
visit(curr->value, EXPRESSION_RESULT));
Ref load = ValueBuilder::makeCall(ABI::wasm2js::SCRATCH_LOAD_F32);
return ValueBuilder::makeSeq(store, load);
}
// Coerce the integer to a float as emscripten does
case ConvertSInt32ToFloat32:
return makeAsmCoercion(
makeAsmCoercion(visit(curr->value, EXPRESSION_RESULT), ASM_INT),
ASM_FLOAT);
case ConvertSInt32ToFloat64:
return makeAsmCoercion(
makeAsmCoercion(visit(curr->value, EXPRESSION_RESULT), ASM_INT),
ASM_DOUBLE);
// Generate (expr >>> 0), followed by a coercion
case ConvertUInt32ToFloat32:
return makeAsmCoercion(
ValueBuilder::makeBinary(visit(curr->value, EXPRESSION_RESULT),
TRSHIFT,
ValueBuilder::makeInt(0)),
ASM_FLOAT);
case ConvertUInt32ToFloat64:
return makeAsmCoercion(
ValueBuilder::makeBinary(visit(curr->value, EXPRESSION_RESULT),
TRSHIFT,
ValueBuilder::makeInt(0)),
ASM_DOUBLE);
// TODO: more complex unary conversions
case NearestFloat32:
case NearestFloat64:
case TruncFloat32:
case TruncFloat64:
std::cerr
<< "operation should have been removed in previous passes"
<< std::endl;
WASM_UNREACHABLE();
default:
std::cerr << "Unhandled unary float operator: " << curr
<< std::endl;
abort();
}
if (curr->type == f32) { // doubles need much less coercing
return makeAsmCoercion(ret, ASM_FLOAT);
}
return ret;
}
default: {
std::cerr << "Unhandled type in unary: " << curr << std::endl;
abort();
}
}
}
Ref visitBinary(Binary* curr) {
// normal binary
Ref left = visit(curr->left, EXPRESSION_RESULT);
Ref right = visit(curr->right, EXPRESSION_RESULT);
Ref ret;
switch (curr->type) {
case i32: {
switch (curr->op) {
case AddInt32:
ret = ValueBuilder::makeBinary(left, PLUS, right);
break;
case SubInt32:
ret = ValueBuilder::makeBinary(left, MINUS, right);
break;
case MulInt32: {
if (curr->type == i32) {
// TODO: when one operand is a small int, emit a multiply
return ValueBuilder::makeCall(MATH_IMUL, left, right);
} else {
return ValueBuilder::makeBinary(left, MUL, right);
}
}
case DivSInt32:
ret = ValueBuilder::makeBinary(makeSigning(left, ASM_SIGNED),
DIV,
makeSigning(right, ASM_SIGNED));
break;
case DivUInt32:
ret = ValueBuilder::makeBinary(makeSigning(left, ASM_UNSIGNED),
DIV,
makeSigning(right, ASM_UNSIGNED));
break;
case RemSInt32:
ret = ValueBuilder::makeBinary(makeSigning(left, ASM_SIGNED),
MOD,
makeSigning(right, ASM_SIGNED));
break;
case RemUInt32:
ret = ValueBuilder::makeBinary(makeSigning(left, ASM_UNSIGNED),
MOD,
makeSigning(right, ASM_UNSIGNED));
break;
case AndInt32:
ret = ValueBuilder::makeBinary(left, AND, right);
break;
case OrInt32:
ret = ValueBuilder::makeBinary(left, OR, right);
break;
case XorInt32:
ret = ValueBuilder::makeBinary(left, XOR, right);
break;
case ShlInt32:
ret = ValueBuilder::makeBinary(left, LSHIFT, right);
break;
case ShrUInt32:
ret = ValueBuilder::makeBinary(left, TRSHIFT, right);
break;
case ShrSInt32:
ret = ValueBuilder::makeBinary(left, RSHIFT, right);
break;
case EqInt32: {
return ValueBuilder::makeBinary(makeSigning(left, ASM_SIGNED),
EQ,
makeSigning(right, ASM_SIGNED));
}
case NeInt32: {
return ValueBuilder::makeBinary(makeSigning(left, ASM_SIGNED),
NE,
makeSigning(right, ASM_SIGNED));
}
case LtSInt32:
return ValueBuilder::makeBinary(makeSigning(left, ASM_SIGNED),
LT,
makeSigning(right, ASM_SIGNED));
case LtUInt32:
return ValueBuilder::makeBinary(makeSigning(left, ASM_UNSIGNED),
LT,
makeSigning(right, ASM_UNSIGNED));
case LeSInt32:
return ValueBuilder::makeBinary(makeSigning(left, ASM_SIGNED),
LE,
makeSigning(right, ASM_SIGNED));
case LeUInt32:
return ValueBuilder::makeBinary(makeSigning(left, ASM_UNSIGNED),
LE,
makeSigning(right, ASM_UNSIGNED));
case GtSInt32:
return ValueBuilder::makeBinary(makeSigning(left, ASM_SIGNED),
GT,
makeSigning(right, ASM_SIGNED));
case GtUInt32:
return ValueBuilder::makeBinary(makeSigning(left, ASM_UNSIGNED),
GT,
makeSigning(right, ASM_UNSIGNED));
case GeSInt32:
return ValueBuilder::makeBinary(makeSigning(left, ASM_SIGNED),
GE,
makeSigning(right, ASM_SIGNED));
case GeUInt32:
return ValueBuilder::makeBinary(makeSigning(left, ASM_UNSIGNED),
GE,
makeSigning(right, ASM_UNSIGNED));
case EqFloat32:
case EqFloat64:
return ValueBuilder::makeBinary(left, EQ, right);
case NeFloat32:
case NeFloat64:
return ValueBuilder::makeBinary(left, NE, right);
case GeFloat32:
case GeFloat64:
return ValueBuilder::makeBinary(left, GE, right);
case GtFloat32:
case GtFloat64:
return ValueBuilder::makeBinary(left, GT, right);
case LeFloat32:
case LeFloat64:
return ValueBuilder::makeBinary(left, LE, right);
case LtFloat32:
case LtFloat64:
return ValueBuilder::makeBinary(left, LT, right);
case RotLInt32:
case RotRInt32:
std::cerr << "should be removed already" << std::endl;
WASM_UNREACHABLE();
default: {
std::cerr << "Unhandled i32 binary operator: " << curr
<< std::endl;
abort();
}
}
break;
}
case f32:
case f64:
switch (curr->op) {
case AddFloat32:
case AddFloat64:
ret = ValueBuilder::makeBinary(left, PLUS, right);
break;
case SubFloat32:
case SubFloat64:
ret = ValueBuilder::makeBinary(left, MINUS, right);
break;
case MulFloat32:
case MulFloat64:
ret = ValueBuilder::makeBinary(left, MUL, right);
break;
case DivFloat32:
case DivFloat64:
ret = ValueBuilder::makeBinary(left, DIV, right);
break;
case MinFloat32:
case MinFloat64:
ret = ValueBuilder::makeCall(MATH_MIN, left, right);
break;
case MaxFloat32:
case MaxFloat64:
ret = ValueBuilder::makeCall(MATH_MAX, left, right);
break;
case CopySignFloat32:
case CopySignFloat64:
default:
std::cerr << "Unhandled binary float operator: " << curr
<< std::endl;
abort();
}
if (curr->type == f32) {
return makeAsmCoercion(ret, ASM_FLOAT);
}
return ret;
default:
std::cerr << "Unhandled type in binary: " << curr << std::endl;
abort();
}
return makeAsmCoercion(ret, wasmToAsmType(curr->type));
}
Ref visitSelect(Select* curr) {
// If the condition has effects that interact with the operands, we must
// reorder it to the start. We must also use locals if the values have
// side effects, as a JS conditional does not visit both sides.
bool useLocals = false;
EffectAnalyzer conditionEffects(parent->options, curr->condition);
EffectAnalyzer ifTrueEffects(parent->options, curr->ifTrue);
EffectAnalyzer ifFalseEffects(parent->options, curr->ifFalse);
if (conditionEffects.invalidates(ifTrueEffects) ||
conditionEffects.invalidates(ifFalseEffects) ||
ifTrueEffects.hasSideEffects() || ifFalseEffects.hasSideEffects()) {
useLocals = true;
}
if (useLocals) {
ScopedTemp tempIfTrue(curr->type, parent, func),
tempIfFalse(curr->type, parent, func),
tempCondition(i32, parent, func);
Ref ifTrue = visit(curr->ifTrue, EXPRESSION_RESULT);
Ref ifFalse = visit(curr->ifFalse, EXPRESSION_RESULT);
Ref condition = visit(curr->condition, EXPRESSION_RESULT);
return ValueBuilder::makeSeq(
ValueBuilder::makeBinary(tempIfTrue.getAstName(), SET, ifTrue),
ValueBuilder::makeSeq(
ValueBuilder::makeBinary(tempIfFalse.getAstName(), SET, ifFalse),
ValueBuilder::makeSeq(
ValueBuilder::makeBinary(
tempCondition.getAstName(), SET, condition),
ValueBuilder::makeConditional(tempCondition.getAstName(),
tempIfTrue.getAstName(),
tempIfFalse.getAstName()))));
} else {
// Simple case without reordering.
return ValueBuilder::makeConditional(
visit(curr->condition, EXPRESSION_RESULT),
visit(curr->ifTrue, EXPRESSION_RESULT),
visit(curr->ifFalse, EXPRESSION_RESULT));
}
}
Ref visitReturn(Return* curr) {
if (!curr->value) {
return ValueBuilder::makeReturn(Ref());
}
Ref val = visit(curr->value, EXPRESSION_RESULT);
bool needCoercion =
parent->options.optimizeLevel == 0 || standaloneFunction ||
parent->functionsCallableFromOutside.count(func->name);
if (needCoercion) {
val = makeAsmCoercion(val, wasmToAsmType(curr->value->type));
}
return ValueBuilder::makeReturn(val);
}
Ref visitHost(Host* curr) {
if (curr->op == HostOp::MemoryGrow) {
if (module->memory.exists &&
module->memory.max > module->memory.initial) {
return ValueBuilder::makeCall(
WASM_MEMORY_GROW,
makeAsmCoercion(visit(curr->operands[0], EXPRESSION_RESULT),
wasmToAsmType(curr->operands[0]->type)));
} else {
return ValueBuilder::makeCall(ABORT_FUNC);
}
} else if (curr->op == HostOp::MemorySize) {
return ValueBuilder::makeCall(WASM_MEMORY_SIZE);
}
WASM_UNREACHABLE(); // TODO
}
Ref visitNop(Nop* curr) { return ValueBuilder::makeToplevel(); }
Ref visitUnreachable(Unreachable* curr) {
return ValueBuilder::makeCall(ABORT_FUNC);
}
private:
Ref makePointer(Expression* ptr, Address offset) {
auto ret = visit(ptr, EXPRESSION_RESULT);
if (offset) {
ret = makeAsmCoercion(
ValueBuilder::makeBinary(ret, PLUS, ValueBuilder::makeNum(offset)),
ASM_INT);
}
return ret;
}
};
return ExpressionProcessor(this, m, func, standaloneFunction)
.visit(func->body, NO_RESULT);
}
void Wasm2JSBuilder::addMemoryGrowthFuncs(Ref ast, Module* wasm) {
Ref memoryGrowFunc = ValueBuilder::makeFunction(WASM_MEMORY_GROW);
ValueBuilder::appendArgumentToFunction(memoryGrowFunc, IString("pagesToAdd"));
memoryGrowFunc[3]->push_back(
ValueBuilder::makeStatement(ValueBuilder::makeBinary(
ValueBuilder::makeName(IString("pagesToAdd")),
SET,
makeAsmCoercion(ValueBuilder::makeName(IString("pagesToAdd")),
AsmType::ASM_INT))));
Ref oldPages = ValueBuilder::makeVar();
memoryGrowFunc[3]->push_back(oldPages);
ValueBuilder::appendToVar(
oldPages,
IString("oldPages"),
makeAsmCoercion(ValueBuilder::makeCall(WASM_MEMORY_SIZE),
AsmType::ASM_INT));
Ref newPages = ValueBuilder::makeVar();
memoryGrowFunc[3]->push_back(newPages);
ValueBuilder::appendToVar(
newPages,
IString("newPages"),
makeAsmCoercion(
ValueBuilder::makeBinary(ValueBuilder::makeName(IString("oldPages")),
PLUS,
ValueBuilder::makeName(IString("pagesToAdd"))),
AsmType::ASM_INT));
Ref block = ValueBuilder::makeBlock();
memoryGrowFunc[3]->push_back(ValueBuilder::makeIf(
ValueBuilder::makeBinary(
ValueBuilder::makeBinary(ValueBuilder::makeName(IString("oldPages")),
LT,
ValueBuilder::makeName(IString("newPages"))),
IString("&&"),
ValueBuilder::makeBinary(ValueBuilder::makeName(IString("newPages")),
LT,
ValueBuilder::makeInt(Memory::kMaxSize))),
block,
NULL));
Ref newBuffer = ValueBuilder::makeVar();
ValueBuilder::appendToBlock(block, newBuffer);
ValueBuilder::appendToVar(
newBuffer,
IString("newBuffer"),
ValueBuilder::makeNew(ValueBuilder::makeCall(
ARRAY_BUFFER,
ValueBuilder::makeCall(MATH_IMUL,
ValueBuilder::makeName(IString("newPages")),
ValueBuilder::makeInt(Memory::kPageSize)))));
Ref newHEAP8 = ValueBuilder::makeVar();
ValueBuilder::appendToBlock(block, newHEAP8);
ValueBuilder::appendToVar(
newHEAP8,
IString("newHEAP8"),
ValueBuilder::makeNew(ValueBuilder::makeCall(
ValueBuilder::makeDot(ValueBuilder::makeName(GLOBAL), INT8ARRAY),
ValueBuilder::makeName(IString("newBuffer")))));
ValueBuilder::appendToBlock(
block,
ValueBuilder::makeCall(
ValueBuilder::makeDot(ValueBuilder::makeName(IString("newHEAP8")),
IString("set")),
ValueBuilder::makeName(HEAP8)));
ValueBuilder::appendToBlock(
block,
ValueBuilder::makeBinary(ValueBuilder::makeName(HEAP8),
SET,
ValueBuilder::makeName(IString("newHEAP8"))));
auto setHeap = [&](IString name, IString view) {
ValueBuilder::appendToBlock(
block,
ValueBuilder::makeBinary(
ValueBuilder::makeName(name),
SET,
ValueBuilder::makeNew(ValueBuilder::makeCall(
ValueBuilder::makeDot(ValueBuilder::makeName(GLOBAL), view),
ValueBuilder::makeName(IString("newBuffer"))))));
};
setHeap(HEAP8, INT8ARRAY);
setHeap(HEAP16, INT16ARRAY);
setHeap(HEAP32, INT32ARRAY);
setHeap(HEAPU8, UINT8ARRAY);
setHeap(HEAPU16, UINT16ARRAY);
setHeap(HEAPU32, UINT32ARRAY);
setHeap(HEAPF32, FLOAT32ARRAY);
setHeap(HEAPF64, FLOAT64ARRAY);
ValueBuilder::appendToBlock(
block,
ValueBuilder::makeBinary(ValueBuilder::makeName(BUFFER),
SET,
ValueBuilder::makeName(IString("newBuffer"))));
// apply the changes to the memory import
if (wasm->memory.imported()) {
ValueBuilder::appendToBlock(
block,
ValueBuilder::makeBinary(
ValueBuilder::makeDot(ValueBuilder::makeName("memory"),
ValueBuilder::makeName(BUFFER)),
SET,
ValueBuilder::makeName(IString("newBuffer"))));
}
memoryGrowFunc[3]->push_back(
ValueBuilder::makeReturn(ValueBuilder::makeName(IString("oldPages"))));
Ref memorySizeFunc = ValueBuilder::makeFunction(WASM_MEMORY_SIZE);
memorySizeFunc[3]->push_back(ValueBuilder::makeReturn(
makeAsmCoercion(ValueBuilder::makeBinary(
ValueBuilder::makeDot(ValueBuilder::makeName(BUFFER),
IString("byteLength")),
DIV,
ValueBuilder::makeInt(Memory::kPageSize)),
AsmType::ASM_INT)));
ast->push_back(memoryGrowFunc);
ast->push_back(memorySizeFunc);
}
// Wasm2JSGlue emits the core of the module - the functions etc. that would
// be the asm.js function in an asm.js world. This class emits the rest of the
// "glue" around that.
class Wasm2JSGlue {
public:
Wasm2JSGlue(Module& wasm,
Output& out,
Wasm2JSBuilder::Flags flags,
Name moduleName)
: wasm(wasm), out(out), flags(flags), moduleName(moduleName) {}
void emitPre();
void emitPost();
private:
Module& wasm;
Output& out;
Wasm2JSBuilder::Flags flags;
Name moduleName;
void emitPreEmscripten();
void emitPreES6();
void emitPostEmscripten();
void emitPostES6();
void emitMemory(std::string buffer,
std::string segmentWriter,
std::function<std::string(std::string)> accessGlobal);
void emitScratchMemorySupport();
};
void Wasm2JSGlue::emitPre() {
if (flags.emscripten) {
emitPreEmscripten();
} else {
emitPreES6();
}
emitScratchMemorySupport();
}
void Wasm2JSGlue::emitPreEmscripten() {
out << "function instantiate(asmLibraryArg, wasmMemory, wasmTable) {\n\n";
}
void Wasm2JSGlue::emitPreES6() {
std::unordered_map<Name, Name> baseModuleMap;
auto noteImport = [&](Name module, Name base) {
// Right now codegen requires a flat namespace going into the module,
// meaning we don't support importing the same name from multiple namespaces
// yet.
if (baseModuleMap.count(base) && baseModuleMap[base] != module) {
Fatal() << "the name " << base << " cannot be imported from "
<< "two different modules yet\n";
abort();
}
baseModuleMap[base] = module;
out << "import { " << base.str << " } from '" << module.str << "';\n";
};
ImportInfo imports(wasm);
ModuleUtils::iterImportedGlobals(
wasm, [&](Global* import) { noteImport(import->module, import->base); });
ModuleUtils::iterImportedFunctions(wasm, [&](Function* import) {
// The scratch memory helpers are emitted in the glue, see code and comments
// below.
if (ABI::wasm2js::isScratchMemoryHelper(import->base)) {
return;
}
noteImport(import->module, import->base);
});
if (wasm.table.exists && wasm.table.imported()) {
out << "import { FUNCTION_TABLE } from 'env';\n";
}
out << '\n';
}
void Wasm2JSGlue::emitPost() {
if (flags.emscripten) {
emitPostEmscripten();
} else {
emitPostES6();
}
}
void Wasm2JSGlue::emitPostEmscripten() {
emitMemory("wasmMemory.buffer", "writeSegment", [](std::string globalName) {
return std::string("asmLibraryArg['") + asmangle(globalName) + "']";
});
out << "return asmFunc({\n"
<< " 'Int8Array': Int8Array,\n"
<< " 'Int16Array': Int16Array,\n"
<< " 'Int32Array': Int32Array,\n"
<< " 'Uint8Array': Uint8Array,\n"
<< " 'Uint16Array': Uint16Array,\n"
<< " 'Uint32Array': Uint32Array,\n"
<< " 'Float32Array': Float32Array,\n"
<< " 'Float64Array': Float64Array,\n"
<< " 'NaN': NaN,\n"
<< " 'Infinity': Infinity,\n"
<< " 'Math': Math\n"
<< " },\n"
<< " asmLibraryArg,\n"
<< " wasmMemory.buffer\n"
<< ")"
<< "\n"
<< "\n"
<< "}";
}
void Wasm2JSGlue::emitPostES6() {
// Create an initial `ArrayBuffer` and populate it with static data.
// Currently we use base64 encoding to encode static data and we decode it at
// instantiation time.
//
// Note that the translation here expects that the lower values of this memory
// can be used for conversions, so make sure there's at least one page.
{
auto pages = wasm.memory.initial == 0 ? 1 : wasm.memory.initial.addr;
out << "var mem" << moduleName.str << " = new ArrayBuffer("
<< pages * Memory::kPageSize << ");\n";
}
emitMemory(std::string("mem") + moduleName.str,
std::string("assign") + moduleName.str,
[](std::string globalName) { return globalName; });
// Actually invoke the `asmFunc` generated function, passing in all global
// values followed by all imports
out << "var ret" << moduleName.str << " = " << moduleName.str << "({"
<< "Math,"
<< "Int8Array,"
<< "Uint8Array,"
<< "Int16Array,"
<< "Uint16Array,"
<< "Int32Array,"
<< "Uint32Array,"
<< "Float32Array,"
<< "Float64Array,"
<< "NaN,"
<< "Infinity"
<< "}, {";
out << "abort:function() { throw new Error('abort'); }";
ModuleUtils::iterImportedFunctions(wasm, [&](Function* import) {
// The scratch memory helpers are emitted in the glue, see code and comments
// below.
if (ABI::wasm2js::isScratchMemoryHelper(import->base)) {
return;
}
out << "," << import->base.str;
});
out << "},mem" << moduleName.str << ");\n";
if (flags.allowAsserts) {
return;
}
// And now that we have our returned instance, export all our functions
// that are hanging off it.
for (auto& exp : wasm.exports) {
switch (exp->kind) {
case ExternalKind::Function:
case ExternalKind::Memory:
break;
// Exported globals and function tables aren't supported yet
default:
continue;
}
std::ostringstream export_name;
for (auto* ptr = exp->name.str; *ptr; ptr++) {
if (*ptr == '-') {
export_name << '_';
} else {
export_name << *ptr;
}
}
out << "export var " << asmangle(exp->name.str) << " = ret"
<< moduleName.str << "." << asmangle(exp->name.str) << ";\n";
}
}
void Wasm2JSGlue::emitMemory(
std::string buffer,
std::string segmentWriter,
std::function<std::string(std::string)> accessGlobal) {
if (wasm.memory.segments.empty()) {
return;
}
auto expr = R"(
function(mem) {
var _mem = new Uint8Array(mem);
return function(offset, s) {
if (typeof Buffer === 'undefined') {
var bytes = atob(s);
for (var i = 0; i < bytes.length; i++)
_mem[offset + i] = bytes.charCodeAt(i);
} else {
var bytes = Buffer.from(s, 'base64');
for (var i = 0; i < bytes.length; i++)
_mem[offset + i] = bytes[i];
}
}
}
)";
// var assign$name = ($expr)(mem$name);
out << "var " << segmentWriter << " = (" << expr << ")(" << buffer << ");\n";
auto globalOffset = [&](const Memory::Segment& segment) {
if (auto* c = segment.offset->template dynCast<Const>()) {
;
return std::to_string(c->value.getInteger());
}
if (auto* get = segment.offset->template dynCast<GlobalGet>()) {
auto internalName = get->name;
auto importedName = wasm.getGlobal(internalName)->base;
return accessGlobal(asmangle(importedName.str));
}
Fatal() << "non-constant offsets aren't supported yet\n";
};
for (auto& seg : wasm.memory.segments) {
assert(!seg.isPassive && "passive segments not implemented yet");
out << segmentWriter << "(" << globalOffset(seg) << ", \""
<< base64Encode(seg.data) << "\");\n";
}
}
void Wasm2JSGlue::emitScratchMemorySupport() {
// The scratch memory helpers are emitted here the glue. We may also want to
// emit them inline at some point. (The reason they are imports is so that
// they appear as "intrinsics" placeholders, and not normal functions that
// the optimizer might want to do something with.)
bool needScratchMemory = false;
ModuleUtils::iterImportedFunctions(wasm, [&](Function* import) {
if (ABI::wasm2js::isScratchMemoryHelper(import->base)) {
needScratchMemory = true;
}
});
if (!needScratchMemory) {
return;
}
out << R"(
var scratchBuffer = new ArrayBuffer(8);
var i32ScratchView = new Int32Array(scratchBuffer);
var f32ScratchView = new Float32Array(scratchBuffer);
var f64ScratchView = new Float64Array(scratchBuffer);
)";
ModuleUtils::iterImportedFunctions(wasm, [&](Function* import) {
if (import->base == ABI::wasm2js::SCRATCH_STORE_I32) {
out << R"(
function wasm2js_scratch_store_i32(index, value) {
i32ScratchView[index] = value;
}
)";
} else if (import->base == ABI::wasm2js::SCRATCH_LOAD_I32) {
out << R"(
function wasm2js_scratch_load_i32(index) {
return i32ScratchView[index];
}
)";
} else if (import->base == ABI::wasm2js::SCRATCH_STORE_I64) {
out << R"(
function legalimport$wasm2js_scratch_store_i64(low, high) {
i32ScratchView[0] = low;
i32ScratchView[1] = high;
}
)";
} else if (import->base == ABI::wasm2js::SCRATCH_LOAD_I64) {
out << R"(
function legalimport$wasm2js_scratch_load_i64() {
if (typeof setTempRet0 === 'function') setTempRet0(i32ScratchView[1]);
return i32ScratchView[0];
}
)";
} else if (import->base == ABI::wasm2js::SCRATCH_STORE_F32) {
out << R"(
function wasm2js_scratch_store_f32(value) {
f32ScratchView[0] = value;
}
)";
} else if (import->base == ABI::wasm2js::SCRATCH_LOAD_F32) {
out << R"(
function wasm2js_scratch_load_f32() {
return f32ScratchView[0];
}
)";
} else if (import->base == ABI::wasm2js::SCRATCH_STORE_F64) {
out << R"(
function wasm2js_scratch_store_f64(value) {
f64ScratchView[0] = value;
}
)";
} else if (import->base == ABI::wasm2js::SCRATCH_LOAD_F64) {
out << R"(
function wasm2js_scratch_load_f64() {
return f64ScratchView[0];
}
)";
}
});
out << '\n';
}
} // namespace wasm
#endif // wasm_wasm2js_h