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#include "stdafx.h"
#include "Loop.h"
#include "Compiler/Exception.h"
namespace storm {
namespace bs {
Loop::Loop(SrcPos pos, Block *parent) : Breakable(pos, parent), anyBreak(false) {}
void Loop::cond(Condition *cond) {
condition = cond;
whileExpr = new (this) CondSuccess(pos, this, cond);
}
Condition *Loop::cond() {
if (!condition)
throw new (this) UsageError(S("Must call 'cond' before creating a while body!"));
return condition;
}
void Loop::condExpr(Expr *e) {
cond(new (this) BoolCondition(e));
}
void Loop::doBody(Expr *e) {
doExpr = e;
if (Block *b = as<Block>(e))
liftVars(b);
}
void Loop::whileBody(Expr *e) {
if (!whileExpr)
whileBlock();
whileExpr->set(e);
}
CondSuccess *Loop::whileBlock() {
if (!whileExpr)
throw new (this) UsageError(S("Must call 'cond' before using the while body!"));
return whileExpr;
}
ExprResult Loop::result() {
if (condition || anyBreak) {
// No reliable value, the last expression in the do part could be used.
return ExprResult();
} else {
// If we don't have a condition, we never return.
return noReturn();
}
}
void Loop::code(CodeGen *s, CodeResult *r) {
using namespace code;
// Outer state where we store our control variable!
CodeGen *outer = s->child();
*s->l << begin(outer->block);
// Inner state, which represents the actual block we're in.
CodeGen *inner = outer->child();
// Initialize variables in the scope.
initVariables(inner);
code(outer, inner, r);
*s->l << end(outer->block);
}
void Loop::code(CodeGen *outerState, CodeGen *innerState, CodeResult *r) {
using namespace code;
Listing *l = innerState->l;
breakBlock = innerState->block;
continueBlock = outerState->block;
before = l->label();
after = l->label();
*l << before;
*l << begin(innerState->block);
// Things in the do-part.
if (doExpr) {
CodeResult *doResult = new (this) CodeResult();
doExpr->code(innerState, doResult);
}
// Check the condition.
if (condition) {
CodeResult *condResult = new (this) CodeResult(Value(StormInfo<Bool>::type(engine())), innerState->block);
condition->code(innerState, condResult);
code::Var c = condResult->location(innerState);
*l << cmp(c, byteConst(0));
*l << jmp(after, ifEqual);
}
// Things in the while-part.
if (whileExpr && whileExpr->any()) {
Label after = innerState->l->label();
CodeResult *whileResult = new (this) CodeResult();
whileExpr->code(innerState, whileResult);
*l << after;
}
// Jump back to the start.
*l << jmpBlock(before, outerState->block);
*l << after;
*l << end(innerState->block);
}
void Loop::willBreak() {
anyBreak = true;
}
void Loop::willContinue() {}
Breakable::To Loop::breakTo() {
return Breakable::To(after, breakBlock);
}
Breakable::To Loop::continueTo() {
return Breakable::To(before, continueBlock);
}
void Loop::toS(StrBuf *to) const {
Bool any = false;
if (doExpr) {
*to << S("do ") << doExpr;
any = true;
}
if (condition) {
if (doExpr)
*to << S(" ");
*to << S("while (") << condition << S(") ");
any = true;
}
if (whileExpr && whileExpr->any()) {
*to << whileExpr;
any = true;
}
if (!any)
*to << S("do {}");
}
}
}
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