public override Reg CGenValue(CGenState state) {
Int32 label_set = state.label_idx;
state.label_idx++;
Int32 label_finish = state.label_idx;
state.label_idx++;
Reg ret = this.Left.CGenValue(state);
switch (ret) {
case Reg.EAX:
state.TESTL(Reg.EAX, Reg.EAX);
state.JNZ(label_set);
break;
case Reg.ST0:
state.FLDZ();
state.FUCOMIP();
state.FSTP(Reg.ST0);
state.JNZ(label_set);
break;
default:
throw new InvalidProgramException();
}
ret = this.Right.CGenValue(state);
switch (ret) {
case Reg.EAX:
state.TESTL(Reg.EAX, Reg.EAX);
state.JNZ(label_set);
break;
case Reg.ST0:
state.FLDZ();
state.FUCOMIP();
state.FSTP(Reg.ST0);
state.JNZ(label_set);
break;
default:
throw new InvalidProgramException();
}
state.MOVL(0, Reg.EAX);
state.JMP(label_finish);
state.CGenLabel(label_set);
state.MOVL(1, Reg.EAX);
state.CGenLabel(label_finish);
return Reg.EAX;
}
//
// test Cond
// jz false ---+
// true_expr |
// +------- jmp finish |
// | false: <--------+
// | false_expr
// +--> finish:
//
public override Reg CGenValue(CGenState state) {
Int32 stack_size = state.StackSize;
Reg ret = this.Cond.CGenValue(state);
state.CGenForceStackSizeTo(stack_size);
// test Cond
switch (ret) {
case Reg.EAX:
state.TESTL(Reg.EAX, Reg.EAX);
break;
case Reg.ST0:
/// Compare Expr with 0.0
/// < see cref = "BinaryComparisonOp.OperateFloat(CGenState)" />
state.FLDZ();
state.FUCOMIP();
state.FSTP(Reg.ST0);
break;
default:
throw new InvalidProgramException();
}
Int32 false_label = state.RequestLabel();
Int32 finish_label = state.RequestLabel();
state.JZ(false_label);
this.TrueExpr.CGenValue(state);
state.JMP(finish_label);
state.CGenLabel(false_label);
ret = this.FalseExpr.CGenValue(state);
state.CGenLabel(finish_label);
return ret;
}
public override void CGenStmt(Env env, CGenState state) {
Int32 label = state.BreakLabel;
state.JMP(label);
}
public override void CGenStmt(Env env, CGenState state) {
ExprType ret_type = env.GetCurrentFunction().ReturnType;
Int32 stack_size = state.StackSize;
if (this.ExprOpt.IsSome) {
// Evaluate the Value.
this.ExprOpt.Value.CGenValue(state);
// If the function returns a struct, copy it to the address given by 8(%ebp).
if (this.ExprOpt.Value.Type is StructOrUnionType) {
state.MOVL(Reg.EAX, Reg.ESI);
state.MOVL(2 * ExprType.SIZEOF_POINTER, Reg.EBP, Reg.EDI);
state.MOVL(this.ExprOpt.Value.Type.SizeOf, Reg.ECX);
state.CGenMemCpy();
state.MOVL(2 * ExprType.SIZEOF_POINTER, Reg.EBP, Reg.EAX);
}
// Restore stack size.
state.CGenForceStackSizeTo(stack_size);
}
// Jump to end of the function.
state.JMP(state.ReturnLabel);
}
public override void CGenStmt(Env env, CGenState state) {
Int32 label = state.GotoLabel(this.Label);
state.JMP(label);
}
public override void CGenStmt(Env env, CGenState state) {
Reg ret = CGenExprStmt(env, this.Cond, state);
CGenTest(ret, state);
Int32 false_label = state.RequestLabel();
Int32 finish_label = state.RequestLabel();
state.JZ(false_label);
this.TrueStmt.CGenStmt(env, state);
state.JMP(finish_label);
state.CGenLabel(false_label);
this.FalseStmt.CGenStmt(env, state);
state.CGenLabel(finish_label);
}
public override void CGenStmt(Env env, CGenState state) {
// Inside a switch statement, the initializations are ignored,
// but the stack size should be changed.
List<Tuple<Env, Decln>> declns;
List<Tuple<Env, Stmt>> stmts;
var compoundStmt = this.Stmt as CompoundStmt;
if (compoundStmt == null) {
throw new NotImplementedException();
}
declns = compoundStmt.Declns;
stmts = compoundStmt.Stmts;
// Track all case values.
IReadOnlyList<Int32> values = CaseLabelsGrabber.GrabLabels(this);
// Make sure there are no duplicates.
if (values.Distinct().Count() != values.Count) {
throw new InvalidOperationException("case labels not unique.");
}
// Request labels for these values.
Dictionary<Int32, Int32> value_to_label = values.ToDictionary(value => value, value => state.RequestLabel());
Int32 label_finish = state.RequestLabel();
Int32 num_default_stmts = stmts.Count(_ => _.Item2 is DefaultStmt);
if (num_default_stmts > 1) {
throw new InvalidOperationException("duplicate defaults.");
}
Int32 label_default =
num_default_stmts == 1 ?
state.RequestLabel() :
label_finish;
Int32 saved_stack_size = state.StackSize;
Int32 stack_size =
declns.Any() ?
declns.Last().Item1.StackSize :
saved_stack_size;
// 1. Evaluate Expr.
CGenExprStmt(env, this.Expr, state);
// 2. Expand stack.
state.CGenForceStackSizeTo(stack_size);
// 3. Make the Jump list.
foreach (KeyValuePair<Int32, Int32> value_label_pair in value_to_label) {
state.CMPL(value_label_pair.Key, Reg.EAX);
state.JZ(value_label_pair.Value);
}
state.JMP(label_default);
// 4. List all the statements.
state.InSwitch(label_finish, label_default, value_to_label);
foreach (Tuple<Env, Stmt> env_stmt_pair in stmts) {
env_stmt_pair.Item2.CGenStmt(env_stmt_pair.Item1, state);
}
state.OutLabels();
// 5. finish:
state.CGenLabel(label_finish);
// 6. Restore stack size.
state.CGenForceStackSizeTo(saved_stack_size);
}
public override void CGenStmt(Env env, CGenState state) {
// Init
this.Init.Map(_ => CGenExprStmt(env, _, state));
Int32 start_label = state.RequestLabel();
Int32 finish_label = state.RequestLabel();
Int32 continue_label = state.RequestLabel();
// start:
state.CGenLabel(start_label);
// test cont
this.Cond.Map(_ => {
Reg ret = CGenExprStmt(env, _, state);
CGenTest(ret, state);
return ret;
});
// jz finish
state.JZ(finish_label);
// Body
state.InLoop(continue_label, finish_label);
this.Body.CGenStmt(env, state);
state.OutLabels();
// continue:
state.CGenLabel(continue_label);
// Loop
this.Loop.Map(_ => CGenExprStmt(env, _, state));
// jmp start
state.JMP(start_label);
// finish:
state.CGenLabel(finish_label);
}
public override void CGenStmt(Env env, CGenState state) {
Int32 start_label = state.RequestLabel();
Int32 finish_label = state.RequestLabel();
// start:
state.CGenLabel(start_label);
// test Cond
Reg ret = CGenExprStmt(env, this.Cond, state);
CGenTest(ret, state);
// jz finish
state.JZ(finish_label);
// Body
state.InLoop(start_label, finish_label);
this.Body.CGenStmt(env, state);
state.OutLabels();
// jmp start
state.JMP(start_label);
// finish:
state.CGenLabel(finish_label);
}
