static void DoConversion (ExprDesc* Expr, const Type* NewType)
/* Emit code to convert the given expression to a new type. */
{
Type* OldType;
unsigned OldSize;
unsigned NewSize;
/* Remember the old type */
OldType = Expr->Type;
/* If we're converting to void, we're done. Note: This does also cover a
* conversion void -> void.
*/
if (IsTypeVoid (NewType)) {
ED_MakeRVal (Expr); /* Never an lvalue */
goto ExitPoint;
}
/* Don't allow casts from void to something else. */
if (IsTypeVoid (OldType)) {
Error ("Cannot convert from `void' to something else");
goto ExitPoint;
}
/* Get the sizes of the types. Since we've excluded void types, checking
* for known sizes makes sense here.
*/
OldSize = CheckedSizeOf (OldType);
NewSize = CheckedSizeOf (NewType);
/* lvalue? */
if (ED_IsLVal (Expr)) {
/* We have an lvalue. If the new size is smaller than the new one,
* we don't need to do anything. The compiler will generate code
* to load only the portion of the value that is actually needed.
* This works only on a little endian architecture, but that's
* what we support.
* If both sizes are equal, do also leave the value alone.
* If the new size is larger, we must convert the value.
*/
if (NewSize > OldSize) {
/* Load the value into the primary */
LoadExpr (CF_NONE, Expr);
/* Emit typecast code */
g_typecast (TypeOf (NewType), TypeOf (OldType) | CF_FORCECHAR);
/* Value is now in primary and an rvalue */
ED_MakeRValExpr (Expr);
}
} else if (ED_IsLocAbs (Expr)) {
/* A cast of a constant numeric value to another type. Be sure
* to handle sign extension correctly.
*/
/* Get the current and new size of the value */
unsigned OldBits = OldSize * 8;
unsigned NewBits = NewSize * 8;
/* Check if the new datatype will have a smaller range. If it
* has a larger range, things are ok, since the value is
* internally already represented by a long.
*/
if (NewBits <= OldBits) {
/* Cut the value to the new size */
Expr->IVal &= (0xFFFFFFFFUL >> (32 - NewBits));
/* If the new type is signed, sign extend the value */
if (IsSignSigned (NewType)) {
if (Expr->IVal & (0x01UL << (NewBits-1))) {
/* Beware: Use the safe shift routine here. */
Expr->IVal |= shl_l (~0UL, NewBits);
}
}
}
} else {
int Statement (int* PendingToken)
/* Statement parser. Returns 1 if the statement does a return/break, returns
** 0 otherwise. If the PendingToken pointer is not NULL, the function will
** not skip the terminating token of the statement (closing brace or
** semicolon), but store true if there is a pending token, and false if there
** is none. The token is always checked, so there is no need for the caller to
** check this token, it must be skipped, however. If the argument pointer is
** NULL, the function will skip the token.
*/
{
ExprDesc Expr;
int GotBreak;
CodeMark Start, End;
/* Assume no pending token */
if (PendingToken) {
*PendingToken = 0;
}
/* Check for a label. A label is always part of a statement, it does not
** replace one.
*/
while (CurTok.Tok == TOK_IDENT && NextTok.Tok == TOK_COLON) {
/* Handle the label */
DoLabel ();
if (CheckLabelWithoutStatement ()) {
return 0;
}
}
switch (CurTok.Tok) {
case TOK_LCURLY:
NextToken ();
GotBreak = CompoundStatement ();
CheckTok (TOK_RCURLY, "`{' expected", PendingToken);
return GotBreak;
case TOK_IF:
return IfStatement ();
case TOK_WHILE:
WhileStatement ();
break;
case TOK_DO:
DoStatement ();
break;
case TOK_SWITCH:
SwitchStatement ();
break;
case TOK_RETURN:
ReturnStatement ();
CheckSemi (PendingToken);
return 1;
case TOK_BREAK:
BreakStatement ();
CheckSemi (PendingToken);
return 1;
case TOK_CONTINUE:
ContinueStatement ();
CheckSemi (PendingToken);
return 1;
case TOK_FOR:
ForStatement ();
break;
case TOK_GOTO:
GotoStatement ();
CheckSemi (PendingToken);
return 1;
case TOK_SEMI:
/* Ignore it */
CheckSemi (PendingToken);
break;
case TOK_PRAGMA:
DoPragma ();
break;
case TOK_CASE:
CaseLabel ();
CheckLabelWithoutStatement ();
break;
case TOK_DEFAULT:
DefaultLabel ();
CheckLabelWithoutStatement ();
break;
default:
/* Remember the current code position */
GetCodePos (&Start);
/* Actual statement */
ExprWithCheck (hie0, &Expr);
/* Load the result only if it is an lvalue and the type is
** marked as volatile. Otherwise the load is useless.
*/
if (ED_IsLVal (&Expr) && IsQualVolatile (Expr.Type)) {
LoadExpr (CF_NONE, &Expr);
}
/* If the statement didn't generate code, and is not of type
** void, emit a warning.
*/
GetCodePos (&End);
if (CodeRangeIsEmpty (&Start, &End) &&
!IsTypeVoid (Expr.Type) &&
IS_Get (&WarnNoEffect)) {
Warning ("Statement has no effect");
}
CheckSemi (PendingToken);
}
return 0;
}
void LoadExpr (unsigned Flags, struct ExprDesc* Expr)
/* Load an expression into the primary register if it is not already there. */
{
if (ED_IsLVal (Expr)) {
/* Dereferenced lvalue. If this is a bit field its type is unsigned.
* But if the field is completely contained in the lower byte, we will
* throw away the high byte anyway and may therefore load just the
* low byte.
*/
if (ED_IsBitField (Expr)) {
Flags |= (Expr->BitOffs + Expr->BitWidth <= CHAR_BITS)? CF_CHAR : CF_INT;
Flags |= CF_UNSIGNED;
} else {
Flags |= TypeOf (Expr->Type);
}
if (ED_NeedsTest (Expr)) {
Flags |= CF_TEST;
}
switch (ED_GetLoc (Expr)) {
case E_LOC_ABS:
/* Absolute: numeric address or const */
g_getstatic (Flags | CF_ABSOLUTE, Expr->IVal, 0);
break;
case E_LOC_GLOBAL:
/* Global variable */
g_getstatic (Flags | CF_EXTERNAL, Expr->Name, Expr->IVal);
break;
case E_LOC_STATIC:
case E_LOC_LITERAL:
/* Static variable or literal in the literal pool */
g_getstatic (Flags | CF_STATIC, Expr->Name, Expr->IVal);
break;
case E_LOC_REGISTER:
/* Register variable */
g_getstatic (Flags | CF_REGVAR, Expr->Name, Expr->IVal);
break;
case E_LOC_STACK:
/* Value on the stack */
g_getlocal (Flags, Expr->IVal);
break;
case E_LOC_PRIMARY:
/* The primary register - just test if necessary */
if (Flags & CF_TEST) {
g_test (Flags);
}
break;
case E_LOC_EXPR:
/* Reference to address in primary with offset in Expr */
g_getind (Flags, Expr->IVal);
break;
default:
Internal ("Invalid location in LoadExpr: 0x%04X", ED_GetLoc (Expr));
}
/* Handle bit fields. The actual type may have been casted or
* converted, so be sure to always use unsigned ints for the
* operations.
*/
if (ED_IsBitField (Expr)) {
unsigned F = CF_INT | CF_UNSIGNED | CF_CONST | (Flags & CF_TEST);
/* Shift right by the bit offset */
g_asr (F, Expr->BitOffs);
/* And by the width if the field doesn't end on an int boundary */
if (Expr->BitOffs + Expr->BitWidth != CHAR_BITS &&
Expr->BitOffs + Expr->BitWidth != INT_BITS) {
g_and (F, (0x0001U << Expr->BitWidth) - 1U);
}
}
/* Expression was tested */
ED_TestDone (Expr);
} else {
/* An rvalue */
if (ED_IsLocExpr (Expr)) {
if (Expr->IVal != 0) {
/* We have an expression in the primary plus a constant
* offset. Adjust the value in the primary accordingly.
*/
Flags |= TypeOf (Expr->Type);
g_inc (Flags | CF_CONST, Expr->IVal);
}
} else {
/* Constant of some sort, load it into the primary */
LoadConstant (Flags, Expr);
}
/* Are we testing this value? */
if (ED_NeedsTest (Expr)) {
/* Yes, force a test */
Flags |= TypeOf (Expr->Type);
g_test (Flags);
ED_TestDone (Expr);
}
}
}
