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//
// WebAssembly-to-asm.js translator. Uses the Emscripten optimizer
// infrastructure.
//
#include "wasm.h"
#include "emscripten-optimizer/optimizer.h"
#include "mixed_arena.h"
namespace wasm {
using namespace cashew;
IString ASM_FUNC("asmFunc");
//
// Wasm2AsmBuilder - converts a WebAssembly module into asm.js
//
class Wasm2AsmBuilder {
MixedArena& allocator;
// How many temp vars we need
int i32s = 0, f32s = 0, f64s = 0;
public:
Asm2WasmBuilder(MixedArena& allocator) : allocator(allocator) {}
Ref processWasm(Module* wasm);
Ref processFunction(Function* func);
//
// Tracks state while converting a function. We need to add new
// temporaries, and overall handle the fact that statements ==
// expressions in wasm, but not asm.js. That means that a wasm
// expression may be turned into an asm.js statement, which we
// cannot just place into an expression, but need to keep
// creating statements until we reach a statement context.
//
// @param receives Whether the context we are in receives a value, or if not,
// then we can drop our return, if we have one.
Ref processExpression(Expression* curr, bool XXX WasmType receives);
};
Ref Wasm2AsmBuilder::processWasm(Module* wasm) {
Ref ret = ValueBuilder::makeTopLevel();
Ref asmFunc = ValueBuilder::makeFunction();
asmFunc[1] = ValueBuilder::makeRawString(ASM_FUNC);
ret[1]->push_back(asmFunc);
// imports XXX
// exports XXX
// functions
for (auto func : wasm->functions) {
asmFunc[3]->push_back(processFunction(func));
}
// table XXX
// memory XXX
return ret;
}
Ref Wasm2AsmBuilder::processFunction(Function* func) {
Ref ret = ValueBuilder::makeFunction();
ret[1] = ValueBuilder::makeRawString(func->name);
// arguments XXX
// body
ret[3]->push_back(processExpression(func->body, func->result != none));
// locals, including new temp locals XXX
return ret;
}
Ref Wasm2AsmBuilder::processExpression(Expression* curr) {
struct ExpressionProcessor : public WasmVisitor<Ref> {
bool receives;
ExpressionProcessor(bool receives) : receives(receives) {}
// 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[0] == BLOCK;
}
// If we replace an expression with a block, and we need to return
// a value, it will show up in the last element, as an assign. This
// returns it.
IString getBlockValue(Ref ast) {
assert(ast.size() >= 2 && ast[1].size() > 0);
Ref last = deStat(ast[1][ast[1].size()-1]);
assert(last[0] == ASSIGN && last[2][0] == NAME);
return last[2][1]->getIString();
}
Ref blockify(Ref ast) {
if (isBlock(ast)) return ast;
Ref ret = ValueBuilder::makeBlock();
ret[1]->push_back(ast);
return ret;
}
Ref blockifyWithValue(Ref ast) {
if (isBlock(ast)) return ast;
Ref ret = ValueBuilder::makeBlock();
ret[1]->push_back(ast);
return ret;
}
// Visitors
void visitBlock(Block *curr) override {
Ref ret = ValueBuilder::makeBlock();
size_t size = curr->list.size();
for (size_t i = 0; i < size; i++) {
ret[1]->push_back(processExpression(func->body, i < size-1 ? false : receives);
}
return ret;
}
void visitIf(If *curr) override {
assert(receives ? !!curr->ifFalse : true); // an if without an else cannot be in a receiving context
Ref condition = processExpression(curr->condition, receives);
Ref ifTrue = processExpression(curr->ifTrue, receives);
Ref ifFalse;
if (curr->ifFalse) {
ifFalse = processExpression(curr->ifFalse, receives);
}
if (!isBlock(condition) && !receives) {
return ValueBuilder::makeIf(condition, ifTrue, ifFalse); // simple if
}
if (receives) {
IString parent->getTemp();
ifTrue = blockifyWithValue(ifTrue);
ifFalse = blockifyWithValue(ifFalse);
}
condition = blockify(blockify);
// just add an if to the block
IString check = getBlockValue(condition);
condition[1]->push_back(ValueBuilder::makeIf(condition, ifTrue, ifFalse));
return condition;
if (isBlock(condition)) {
}
}
void visitLoop(Loop *curr) override {
}
void visitLabel(Label *curr) override {
}
void visitBreak(Break *curr) override {
}
void visitSwitch(Switch *curr) override {
}
void visitCall(Call *curr) override {
}
void visitCallImport(CallImport *curr) override {
}
void visitCallIndirect(CallIndirect *curr) override {
}
void visitGetLocal(GetLocal *curr) override {
}
void visitSetLocal(SetLocal *curr) override {
}
void visitLoad(Load *curr) override {
}
void visitStore(Store *curr) override {
}
void visitConst(Const *curr) override {
}
void visitUnary(Unary *curr) override {
}
void visitBinary(Binary *curr) override {
}
void visitCompare(Compare *curr) override {
}
void visitConvert(Convert *curr) override {
}
void visitSelect(Select *curr) override {
}
void visitHost(Host *curr) override {
}
void visitNop(Nop *curr) override {
}
void visitUnreachable(Unreachable *curr) override {
}
};
return ExpressionProcessor(state).visit(curr);
}
} // namespace wasm
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