/*****************************************************************************/
-/* Forwards */
+/* Data */
+/*****************************************************************************/
+
+
+
+typedef struct StructInitData StructInitData;
+struct StructInitData {
+ unsigned Size; /* Size of struct */
+ unsigned Offs; /* Current offset in struct */
+ unsigned BitVal; /* Summed up bit-field value */
+ unsigned ValBits; /* Valid bits in Val */
+};
+
+
+
+/*****************************************************************************/
+/* Forwards */
/*****************************************************************************/
/*****************************************************************************/
-/* internal functions */
+/* Internal functions */
/*****************************************************************************/
unsigned StructSize;
int FlexibleMember;
- unsigned Offs;
int BitOffs; /* Bit offset for bit-fields */
int FieldWidth; /* Width in bits, -1 if not a bit-field */
SymTable* FieldTab;
while (1) {
Declaration Decl;
+ ident Ident;
/* If we had a flexible array member before, no other fields can
* follow.
/* If this is not a bit field, or the bit field is too large for
* the remainder of the current member, or we have a bit field
- * with width zero, align the struct to the next member
+ * with width zero, align the struct to the next member by adding
+ * a member with an anonymous name.
*/
if (BitOffs > 0) {
if (FieldWidth <= 0 || (BitOffs + FieldWidth) > (int) INT_BITS) {
+
+ /* We need an anonymous name */
+ AnonName (Ident, "bit-field");
+
+ /* Add an anonymous bit-field that aligns to the next
+ * storage unit.
+ */
+ AddBitField (Ident, StructSize, BitOffs, INT_BITS - BitOffs);
+
+ /* No bits left */
StructSize += SIZEOF_INT;
BitOffs = 0;
}
Warning ("Declaration does not declare anything");
goto NextMember;
} else {
- /* A bit-field without a name will just increase the
- * offset
- */
- BitOffs += FieldWidth;
- goto NextMember;
+ /* A bit-field without a name will get an anonymous one */
+ AnonName (Decl.Ident, "bit-field");
}
}
- /* Byte offset of this member is the current struct size plus any
- * full bytes from the bit offset in case of bit-fields.
- */
- Offs = StructSize + (BitOffs / CHAR_BITS);
-
/* Check if this field is a flexible array member, and
* calculate the size of the field.
*/
FlexibleMember = 1;
/* Assume zero for size calculations */
SetElementCount (Decl.Type, FLEXIBLE);
- } else if (FieldWidth < 0) {
- StructSize += CheckedSizeOf (Decl.Type);
}
/* Add a field entry to the table */
- if (FieldWidth > 0) {
+ if (FieldWidth > 0) {
+ /* Add full byte from the bit offset to the variable offset.
+ * This simplifies handling he bit-field as a char type
+ * in expressions.
+ */
+ unsigned Offs = StructSize + (BitOffs / CHAR_BITS);
AddBitField (Decl.Ident, Offs, BitOffs % CHAR_BITS, FieldWidth);
BitOffs += FieldWidth;
+ CHECK (BitOffs <= (int) INT_BITS);
+ if (BitOffs == INT_BITS) {
+ StructSize += SIZEOF_INT;
+ BitOffs = 0;
+ }
} else {
- AddLocalSym (Decl.Ident, Decl.Type, SC_STRUCTFIELD, Offs);
+ AddLocalSym (Decl.Ident, Decl.Type, SC_STRUCTFIELD, StructSize);
+ StructSize += CheckedSizeOf (Decl.Type);
}
NextMember: if (CurTok.Tok != TOK_COMMA) {
-static unsigned ParseScalarInit (Type* T)
-/* Parse initializaton for scalar data types. Return the number of data bytes. */
+static void OutputBitFieldData (StructInitData* SI)
+/* Output bit field data */
{
- ExprDesc ED;
+ /* Ignore if we have no data */
+ if (SI->ValBits > 0) {
+
+ /* Output the data */
+ g_defdata (CF_INT | CF_UNSIGNED | CF_CONST, SI->BitVal, 0);
+
+ /* Clear the data from SI and account for the size */
+ SI->BitVal = 0;
+ SI->ValBits = 0;
+ SI->Offs += SIZEOF_INT;
+ }
+}
+
+
+static void ParseScalarInitInternal (Type* T, ExprDesc* ED)
+/* Parse initializaton for scalar data types. This function will not output the
+ * data but return it in ED.
+ */
+{
/* Optional opening brace */
unsigned BraceCount = OpeningCurlyBraces (0);
}
/* Get the expression and convert it to the target type */
- ConstExpr (hie1, &ED);
- TypeConversion (&ED, T);
-
- /* Output the data */
- DefineData (&ED);
+ ConstExpr (hie1, ED);
+ TypeConversion (ED, T);
/* Close eventually opening braces */
ClosingCurlyBraces (BraceCount);
+}
+
+
+
+static unsigned ParseScalarInit (Type* T)
+/* Parse initializaton for scalar data types. Return the number of data bytes. */
+{
+ ExprDesc ED;
+
+ /* Parse initialization */
+ ParseScalarInitInternal (T, &ED);
+
+ /* Output the data */
+ DefineData (&ED);
/* Done */
return SizeOf (T);
static unsigned ParseStructInit (Type* T, int AllowFlexibleMembers)
/* Parse initialization of a struct or union. Return the number of data bytes. */
{
- SymEntry* Entry;
- SymTable* Tab;
- unsigned StructSize;
- unsigned Size;
+ SymEntry* Entry;
+ SymTable* Tab;
+ StructInitData SI;
/* Consume the opening curly brace */
Entry = GetSymEntry (T);
/* Get the size of the struct from the symbol table entry */
- StructSize = Entry->V.S.Size;
+ SI.Size = Entry->V.S.Size;
/* Check if this struct definition has a field table. If it doesn't, it
* is an incomplete definition.
*/
Tab = Entry->V.S.SymTab;
if (Tab == 0) {
- Error ("Cannot initialize variables with incomplete type");
+ Error ("Cannot initialize variables with incomplete type");
/* Try error recovery */
SkipInitializer (1);
- /* Nothing initialized */
- return 0;
+ /* Nothing initialized */
+ return 0;
}
/* Get a pointer to the list of symbols */
Entry = Tab->SymHead;
/* Initialize fields */
- Size = 0;
+ SI.Offs = 0;
+ SI.BitVal = 0;
+ SI.ValBits = 0;
while (CurTok.Tok != TOK_RCURLY) {
- if (Entry == 0) {
- Error ("Too many initializers");
+
+ /* */
+ if (Entry == 0) {
+ Error ("Too many initializers");
SkipInitializer (1);
- return Size;
+ return SI.Offs;
}
- /* Parse initialization of one field. Flexible array members may
- * only be initialized if they are the last field (or part of the
- * last struct field).
+
+ /* Parse initialization of one field. Bit-fields need a special
+ * handling.
*/
- Size += ParseInitInternal (Entry->Type, AllowFlexibleMembers && Entry->NextSym == 0);
+ if (SymIsBitField (Entry)) {
- /* For unions, only the first member can be initialized */
- if (IsTypeStruct (T)) {
- /* Struct */
- Entry = Entry->NextSym;
- } else {
- /* Union */
- Entry = 0;
+ ExprDesc ED;
+ unsigned Val;
+ unsigned Shift;
+
+ /* Calculate the bitmask from the bit-field data */
+ unsigned Mask = (1U << Entry->V.B.BitWidth) - 1U;
+
+ /* Safety ... */
+ CHECK (Entry->V.B.Offs * CHAR_BITS + Entry->V.B.BitOffs ==
+ SI.Offs * CHAR_BITS + SI.ValBits);
+
+ /* This may be an anonymous bit-field, in which case it doesn't
+ * have an initializer.
+ */
+ if (IsAnonName (Entry->Name)) {
+ /* Account for the data and output it if we have a full word */
+ SI.ValBits += Entry->V.B.BitWidth;
+ CHECK (SI.ValBits <= INT_BITS);
+ if (SI.ValBits == INT_BITS) {
+ OutputBitFieldData (&SI);
+ }
+ goto NextMember;
+ } else {
+ /* Read the data, check for a constant integer, do a range
+ * check.
+ */
+ ParseScalarInitInternal (type_uint, &ED);
+ if (!ED_IsConstAbsInt (&ED)) {
+ Error ("Constant initializer expected");
+ ED_MakeConstAbsInt (&ED, 1);
+ }
+ if (ED.IVal > (long) Mask) {
+ Warning ("Truncating value in bit-field initializer");
+ ED.IVal &= (long) Mask;
+ }
+ Val = (unsigned) ED.IVal;
+ }
+
+ /* Add the value to the currently stored bit-field value */
+ Shift = (Entry->V.B.Offs - SI.Offs) * CHAR_BITS + Entry->V.B.BitOffs;
+ SI.BitVal |= (Val << Shift);
+
+ /* Account for the data and output it if we have a full word */
+ SI.ValBits += Entry->V.B.BitWidth;
+ CHECK (SI.ValBits <= INT_BITS);
+ if (SI.ValBits == INT_BITS) {
+ OutputBitFieldData (&SI);
+ }
+
+ } else {
+
+ /* Standard member. We should never have stuff from a
+ * bit-field left
+ */
+ CHECK (SI.ValBits == 0);
+
+ /* Flexible array members may only be initialized if they are
+ * the last field (or part of the last struct field).
+ */
+ SI.Offs += ParseInitInternal (Entry->Type, AllowFlexibleMembers && Entry->NextSym == 0);
}
/* More initializers? */
- if (CurTok.Tok == TOK_COMMA) {
- NextToken ();
- } else {
+ if (CurTok.Tok != TOK_COMMA) {
break;
}
+
+ /* Skip the comma */
+ NextToken ();
+
+NextMember:
+ /* Next member. For unions, only the first one can be initialized */
+ if (IsTypeUnion (T)) {
+ /* Union */
+ Entry = 0;
+ } else {
+ /* Struct */
+ Entry = Entry->NextSym;
+ }
}
/* Consume the closing curly brace */
ConsumeRCurly ();
+ /* If we have data from a bit-field left, output it now */
+ OutputBitFieldData (&SI);
+
/* If there are struct fields left, reserve additional storage */
- if (Size < StructSize) {
- g_zerobytes (StructSize - Size);
- Size = StructSize;
+ if (SI.Offs < SI.Size) {
+ g_zerobytes (SI.Size - SI.Offs);
+ SI.Offs = SI.Size;
}
/* Return the actual number of bytes initialized. This number may be
- * larger than StructSize if flexible array members are present and were
- * initialized (possible in non ANSI mode).
+ * larger than sizeof (Struct) if flexible array members are present and
+ * were initialized (possible in non ANSI mode).
*/
- return Size;
+ return SI.Offs;
}
projects / cc65 / commitdiff