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Fixed padding at the ends of structs with bit-fields.

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acqn
2020-07-29 15:09:53 +08:00
committed by Oliver Schmidt
parent 8a511bb63d
commit e38f601fcc
1 changed files with 29 additions and 13 deletions
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42
src/cc65/declare.c
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@@ -717,6 +717,29 @@ static int ParseFieldWidth (Declaration* Decl)
static unsigned PadWithBitField (unsigned StructSize, unsigned BitOffs)
/* Pad the current struct with an anonymous bit-field aligned to the next byte.
** Return how many bits are used to pad.
*/
{
/* MSVC complains about unary negation of unsigned,
** so it has been rewritten as subtraction.
*/
unsigned PaddingBits = (0 - BitOffs) % CHAR_BITS;
/* We need an anonymous name */
ident Ident;
AnonName (Ident, "bit-field");
/* Add an anonymous bit-field that aligns to the next
** byte.
*/
AddBitField (Ident, StructSize, BitOffs, PaddingBits);
return PaddingBits;
}
static unsigned AliasAnonStructFields (const Declaration* Decl, SymEntry* Anon) static unsigned AliasAnonStructFields (const Declaration* Decl, SymEntry* Anon)
/* Create alias fields from an anon union/struct in the current lexical level. /* Create alias fields from an anon union/struct in the current lexical level.
** The function returns the count of created aliases. ** The function returns the count of created aliases.
@@ -919,7 +942,6 @@ static SymEntry* ParseStructDecl (const char* Name)
while (1) { while (1) {
Declaration Decl; Declaration Decl;
ident Ident;
/* If we had a flexible array member before, no other fields can /* If we had a flexible array member before, no other fields can
** follow. ** follow.
@@ -942,19 +964,10 @@ static SymEntry* ParseStructDecl (const char* Name)
*/ */
if (BitOffs > 0) { if (BitOffs > 0) {
if (FieldWidth <= 0 || (BitOffs + FieldWidth) > INT_BITS) { if (FieldWidth <= 0 || (BitOffs + FieldWidth) > INT_BITS) {
/* Bits needed to byte-align the next field.
** MSVC complains about unary negation of unsigned,
** so it has been rewritten as subtraction.
*/
unsigned PaddingBits = (0 - BitOffs) % CHAR_BITS;
/* We need an anonymous name */
AnonName (Ident, "bit-field");
/* Add an anonymous bit-field that aligns to the next /* Add an anonymous bit-field that aligns to the next
** byte. ** byte.
*/ */
AddBitField (Ident, StructSize, BitOffs, PaddingBits); unsigned PaddingBits = PadWithBitField (StructSize, BitOffs);
/* No bits left */ /* No bits left */
StructSize += (BitOffs + PaddingBits) / CHAR_BITS; StructSize += (BitOffs + PaddingBits) / CHAR_BITS;
@@ -1039,9 +1052,12 @@ NextMember: if (CurTok.Tok != TOK_COMMA) {
ConsumeSemi (); ConsumeSemi ();
} }
/* If we have bits from bit-fields left, add them to the size. */
if (BitOffs > 0) { if (BitOffs > 0) {
StructSize += ((BitOffs + CHAR_BITS - 1) / CHAR_BITS); /* If we have bits from bit-fields left, pad the struct to next byte */
unsigned PaddingBits = PadWithBitField (StructSize, BitOffs);
/* No bits left */
StructSize += (BitOffs + PaddingBits) / CHAR_BITS;
} }
/* Skip the closing brace */ /* Skip the closing brace */