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Obey strict aliasing rule in linked lists

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Christopher Head 2020-04-16 17:35:25 -07:00
parent 1abca83c89
commit d3ae502ba2
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3 changed files with 41 additions and 43 deletions
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10
event_groups.c
View file

@ -518,8 +518,8 @@ EventBits_t uxReturn;
EventBits_t xEventGroupSetBits( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet ) EventBits_t xEventGroupSetBits( EventGroupHandle_t xEventGroup, const EventBits_t uxBitsToSet )
{ {
ListItem_t *pxListItem, *pxNext; MiniListItem_t *pxListItem, *pxNext;
ListItem_t const *pxListEnd; MiniListItem_t const *pxListEnd;
List_t const * pxList; List_t const * pxList;
EventBits_t uxBitsToClear = 0, uxBitsWaitedFor, uxControlBits; EventBits_t uxBitsToClear = 0, uxBitsWaitedFor, uxControlBits;
EventGroup_t *pxEventBits = xEventGroup; EventGroup_t *pxEventBits = xEventGroup;
@ -545,7 +545,7 @@ BaseType_t xMatchFound = pdFALSE;
while( pxListItem != pxListEnd ) while( pxListItem != pxListEnd )
{ {
pxNext = listGET_NEXT( pxListItem ); pxNext = listGET_NEXT( pxListItem );
uxBitsWaitedFor = listGET_LIST_ITEM_VALUE( pxListItem ); uxBitsWaitedFor = listGET_LIST_ITEM_VALUE( ( ListItem_t * ) pxListItem );
xMatchFound = pdFALSE; xMatchFound = pdFALSE;
/* Split the bits waited for from the control bits. */ /* Split the bits waited for from the control bits. */
@ -591,7 +591,7 @@ BaseType_t xMatchFound = pdFALSE;
eventUNBLOCKED_DUE_TO_BIT_SET bit is set so the task knows eventUNBLOCKED_DUE_TO_BIT_SET bit is set so the task knows
that is was unblocked due to its required bits matching, rather that is was unblocked due to its required bits matching, rather
than because it timed out. */ than because it timed out. */
vTaskRemoveFromUnorderedEventList( pxListItem, pxEventBits->uxEventBits | eventUNBLOCKED_DUE_TO_BIT_SET ); vTaskRemoveFromUnorderedEventList( ( ListItem_t * ) pxListItem, pxEventBits->uxEventBits | eventUNBLOCKED_DUE_TO_BIT_SET );
} }
/* Move onto the next list item. Note pxListItem->pxNext is not /* Move onto the next list item. Note pxListItem->pxNext is not
@ -624,7 +624,7 @@ const List_t *pxTasksWaitingForBits = &( pxEventBits->xTasksWaitingForBits );
/* Unblock the task, returning 0 as the event list is being deleted /* Unblock the task, returning 0 as the event list is being deleted
and cannot therefore have any bits set. */ and cannot therefore have any bits set. */
configASSERT( pxTasksWaitingForBits->xListEnd.pxNext != ( const ListItem_t * ) &( pxTasksWaitingForBits->xListEnd ) ); configASSERT( pxTasksWaitingForBits->xListEnd.pxNext != ( const ListItem_t * ) &( pxTasksWaitingForBits->xListEnd ) );
vTaskRemoveFromUnorderedEventList( pxTasksWaitingForBits->xListEnd.pxNext, eventUNBLOCKED_DUE_TO_BIT_SET ); vTaskRemoveFromUnorderedEventList( (ListItem_t *) pxTasksWaitingForBits->xListEnd.pxNext, eventUNBLOCKED_DUE_TO_BIT_SET );
} }
#if( ( configSUPPORT_DYNAMIC_ALLOCATION == 1 ) && ( configSUPPORT_STATIC_ALLOCATION == 0 ) ) #if( ( configSUPPORT_DYNAMIC_ALLOCATION == 1 ) && ( configSUPPORT_STATIC_ALLOCATION == 0 ) )

36
include/list.h
View file

@ -137,27 +137,25 @@ use of FreeRTOS.*/
* Definition of the only type of object that a list can contain. * Definition of the only type of object that a list can contain.
*/ */
struct xLIST; struct xLIST;
struct xLIST_ITEM
{
listFIRST_LIST_ITEM_INTEGRITY_CHECK_VALUE /*< Set to a known value if configUSE_LIST_DATA_INTEGRITY_CHECK_BYTES is set to 1. */
configLIST_VOLATILE TickType_t xItemValue; /*< The value being listed. In most cases this is used to sort the list in descending order. */
struct xLIST_ITEM * configLIST_VOLATILE pxNext; /*< Pointer to the next ListItem_t in the list. */
struct xLIST_ITEM * configLIST_VOLATILE pxPrevious; /*< Pointer to the previous ListItem_t in the list. */
void * pvOwner; /*< Pointer to the object (normally a TCB) that contains the list item. There is therefore a two way link between the object containing the list item and the list item itself. */
struct xLIST * configLIST_VOLATILE pxContainer; /*< Pointer to the list in which this list item is placed (if any). */
listSECOND_LIST_ITEM_INTEGRITY_CHECK_VALUE /*< Set to a known value if configUSE_LIST_DATA_INTEGRITY_CHECK_BYTES is set to 1. */
};
typedef struct xLIST_ITEM ListItem_t; /* For some reason lint wants this as two separate definitions. */
struct xMINI_LIST_ITEM struct xMINI_LIST_ITEM
{ {
listFIRST_LIST_ITEM_INTEGRITY_CHECK_VALUE /*< Set to a known value if configUSE_LIST_DATA_INTEGRITY_CHECK_BYTES is set to 1. */ listFIRST_LIST_ITEM_INTEGRITY_CHECK_VALUE /*< Set to a known value if configUSE_LIST_DATA_INTEGRITY_CHECK_BYTES is set to 1. */
configLIST_VOLATILE TickType_t xItemValue; configLIST_VOLATILE TickType_t xItemValue;
struct xLIST_ITEM * configLIST_VOLATILE pxNext; struct xMINI_LIST_ITEM * configLIST_VOLATILE pxNext;
struct xLIST_ITEM * configLIST_VOLATILE pxPrevious; struct xMINI_LIST_ITEM * configLIST_VOLATILE pxPrevious;
}; };
typedef struct xMINI_LIST_ITEM MiniListItem_t; typedef struct xMINI_LIST_ITEM MiniListItem_t;
struct xLIST_ITEM
{
MiniListItem_t xMiniItem; /*< The item value and next and previous pointers. */
void * pvOwner; /*< Pointer to the object (normally a TCB) that contains the list item. There is therefore a two way link between the object containing the list item and the list item itself. */
struct xLIST * configLIST_VOLATILE pxContainer; /*< Pointer to the list in which this list item is placed (if any). */
listSECOND_LIST_ITEM_INTEGRITY_CHECK_VALUE /*< Set to a known value if configUSE_LIST_DATA_INTEGRITY_CHECK_BYTES is set to 1. */
};
typedef struct xLIST_ITEM ListItem_t; /* For some reason lint wants this as two separate definitions. */
/* /*
* Definition of the type of queue used by the scheduler. * Definition of the type of queue used by the scheduler.
*/ */
@ -165,7 +163,7 @@ typedef struct xLIST
{ {
listFIRST_LIST_INTEGRITY_CHECK_VALUE /*< Set to a known value if configUSE_LIST_DATA_INTEGRITY_CHECK_BYTES is set to 1. */ listFIRST_LIST_INTEGRITY_CHECK_VALUE /*< Set to a known value if configUSE_LIST_DATA_INTEGRITY_CHECK_BYTES is set to 1. */
volatile UBaseType_t uxNumberOfItems; volatile UBaseType_t uxNumberOfItems;
ListItem_t * configLIST_VOLATILE pxIndex; /*< Used to walk through the list. Points to the last item returned by a call to listGET_OWNER_OF_NEXT_ENTRY (). */ MiniListItem_t * configLIST_VOLATILE pxIndex; /*< Used to walk through the list. Points to the last item returned by a call to listGET_OWNER_OF_NEXT_ENTRY (). */
MiniListItem_t xListEnd; /*< List item that contains the maximum possible item value meaning it is always at the end of the list and is therefore used as a marker. */ MiniListItem_t xListEnd; /*< List item that contains the maximum possible item value meaning it is always at the end of the list and is therefore used as a marker. */
listSECOND_LIST_INTEGRITY_CHECK_VALUE /*< Set to a known value if configUSE_LIST_DATA_INTEGRITY_CHECK_BYTES is set to 1. */ listSECOND_LIST_INTEGRITY_CHECK_VALUE /*< Set to a known value if configUSE_LIST_DATA_INTEGRITY_CHECK_BYTES is set to 1. */
} List_t; } List_t;
@ -195,7 +193,7 @@ typedef struct xLIST
* \page listSET_LIST_ITEM_VALUE listSET_LIST_ITEM_VALUE * \page listSET_LIST_ITEM_VALUE listSET_LIST_ITEM_VALUE
* \ingroup LinkedList * \ingroup LinkedList
*/ */
#define listSET_LIST_ITEM_VALUE( pxListItem, xValue ) ( ( pxListItem )->xItemValue = ( xValue ) ) #define listSET_LIST_ITEM_VALUE( pxListItem, xValue ) ( ( pxListItem )->xMiniItem.xItemValue = ( xValue ) )
/* /*
* Access macro to retrieve the value of the list item. The value can * Access macro to retrieve the value of the list item. The value can
@ -205,7 +203,7 @@ typedef struct xLIST
* \page listGET_LIST_ITEM_VALUE listGET_LIST_ITEM_VALUE * \page listGET_LIST_ITEM_VALUE listGET_LIST_ITEM_VALUE
* \ingroup LinkedList * \ingroup LinkedList
*/ */
#define listGET_LIST_ITEM_VALUE( pxListItem ) ( ( pxListItem )->xItemValue ) #define listGET_LIST_ITEM_VALUE( pxListItem ) ( ( pxListItem )->xMiniItem.xItemValue )
/* /*
* Access macro to retrieve the value of the list item at the head of a given * Access macro to retrieve the value of the list item at the head of a given
@ -238,7 +236,7 @@ typedef struct xLIST
* \page listGET_END_MARKER listGET_END_MARKER * \page listGET_END_MARKER listGET_END_MARKER
* \ingroup LinkedList * \ingroup LinkedList
*/ */
#define listGET_END_MARKER( pxList ) ( ( ListItem_t const * ) ( &( ( pxList )->xListEnd ) ) ) #define listGET_END_MARKER( pxList ) ( ( MiniListItem_t const * ) ( &( ( pxList )->xListEnd ) ) )
/* /*
* Access macro to determine if a list contains any items. The macro will * Access macro to determine if a list contains any items. The macro will
@ -284,7 +282,7 @@ List_t * const pxConstList = ( pxList ); \
{ \ { \
( pxConstList )->pxIndex = ( pxConstList )->pxIndex->pxNext; \ ( pxConstList )->pxIndex = ( pxConstList )->pxIndex->pxNext; \
} \ } \
( pxTCB ) = ( pxConstList )->pxIndex->pvOwner; \ ( pxTCB ) = ( ( ListItem_t * ) ( pxConstList )->pxIndex )->pvOwner; \
} }
@ -304,7 +302,7 @@ List_t * const pxConstList = ( pxList ); \
* \page listGET_OWNER_OF_HEAD_ENTRY listGET_OWNER_OF_HEAD_ENTRY * \page listGET_OWNER_OF_HEAD_ENTRY listGET_OWNER_OF_HEAD_ENTRY
* \ingroup LinkedList * \ingroup LinkedList
*/ */
#define listGET_OWNER_OF_HEAD_ENTRY( pxList ) ( (&( ( pxList )->xListEnd ))->pxNext->pvOwner ) #define listGET_OWNER_OF_HEAD_ENTRY( pxList ) ( ( ( ListItem_t * ) (&( ( pxList )->xListEnd ))->pxNext )->pvOwner )
/* /*
* Check to see if a list item is within a list. The list item maintains a * Check to see if a list item is within a list. The list item maintains a

38
list.c
View file

@ -39,7 +39,7 @@ void vListInitialise( List_t * const pxList )
/* The list structure contains a list item which is used to mark the /* The list structure contains a list item which is used to mark the
end of the list. To initialise the list the list end is inserted end of the list. To initialise the list the list end is inserted
as the only list entry. */ as the only list entry. */
pxList->pxIndex = ( ListItem_t * ) &( pxList->xListEnd ); /*lint !e826 !e740 !e9087 The mini list structure is used as the list end to save RAM. This is checked and valid. */ pxList->pxIndex = &( pxList->xListEnd ); /*lint !e826 !e740 !e9087 The mini list structure is used as the list end to save RAM. This is checked and valid. */
/* The list end value is the highest possible value in the list to /* The list end value is the highest possible value in the list to
ensure it remains at the end of the list. */ ensure it remains at the end of the list. */
@ -47,8 +47,8 @@ void vListInitialise( List_t * const pxList )
/* The list end next and previous pointers point to itself so we know /* The list end next and previous pointers point to itself so we know
when the list is empty. */ when the list is empty. */
pxList->xListEnd.pxNext = ( ListItem_t * ) &( pxList->xListEnd ); /*lint !e826 !e740 !e9087 The mini list structure is used as the list end to save RAM. This is checked and valid. */ pxList->xListEnd.pxNext = &( pxList->xListEnd ); /*lint !e826 !e740 !e9087 The mini list structure is used as the list end to save RAM. This is checked and valid. */
pxList->xListEnd.pxPrevious = ( ListItem_t * ) &( pxList->xListEnd );/*lint !e826 !e740 !e9087 The mini list structure is used as the list end to save RAM. This is checked and valid. */ pxList->xListEnd.pxPrevious = &( pxList->xListEnd );/*lint !e826 !e740 !e9087 The mini list structure is used as the list end to save RAM. This is checked and valid. */
pxList->uxNumberOfItems = ( UBaseType_t ) 0U; pxList->uxNumberOfItems = ( UBaseType_t ) 0U;
@ -73,7 +73,7 @@ void vListInitialiseItem( ListItem_t * const pxItem )
void vListInsertEnd( List_t * const pxList, ListItem_t * const pxNewListItem ) void vListInsertEnd( List_t * const pxList, ListItem_t * const pxNewListItem )
{ {
ListItem_t * const pxIndex = pxList->pxIndex; MiniListItem_t * const pxIndex = pxList->pxIndex;
/* Only effective when configASSERT() is also defined, these tests may catch /* Only effective when configASSERT() is also defined, these tests may catch
the list data structures being overwritten in memory. They will not catch the list data structures being overwritten in memory. They will not catch
@ -84,14 +84,14 @@ ListItem_t * const pxIndex = pxList->pxIndex;
/* Insert a new list item into pxList, but rather than sort the list, /* Insert a new list item into pxList, but rather than sort the list,
makes the new list item the last item to be removed by a call to makes the new list item the last item to be removed by a call to
listGET_OWNER_OF_NEXT_ENTRY(). */ listGET_OWNER_OF_NEXT_ENTRY(). */
pxNewListItem->pxNext = pxIndex; pxNewListItem->xMiniItem.pxNext = pxIndex;
pxNewListItem->pxPrevious = pxIndex->pxPrevious; pxNewListItem->xMiniItem.pxPrevious = pxIndex->pxPrevious;
/* Only used during decision coverage testing. */ /* Only used during decision coverage testing. */
mtCOVERAGE_TEST_DELAY(); mtCOVERAGE_TEST_DELAY();
pxIndex->pxPrevious->pxNext = pxNewListItem; pxIndex->pxPrevious->pxNext = &pxNewListItem->xMiniItem;
pxIndex->pxPrevious = pxNewListItem; pxIndex->pxPrevious = &pxNewListItem->xMiniItem;
/* Remember which list the item is in. */ /* Remember which list the item is in. */
pxNewListItem->pxContainer = pxList; pxNewListItem->pxContainer = pxList;
@ -102,8 +102,8 @@ ListItem_t * const pxIndex = pxList->pxIndex;
void vListInsert( List_t * const pxList, ListItem_t * const pxNewListItem ) void vListInsert( List_t * const pxList, ListItem_t * const pxNewListItem )
{ {
ListItem_t *pxIterator; MiniListItem_t *pxIterator;
const TickType_t xValueOfInsertion = pxNewListItem->xItemValue; const TickType_t xValueOfInsertion = pxNewListItem->xMiniItem.xItemValue;
/* Only effective when configASSERT() is also defined, these tests may catch /* Only effective when configASSERT() is also defined, these tests may catch
the list data structures being overwritten in memory. They will not catch the list data structures being overwritten in memory. They will not catch
@ -147,17 +147,17 @@ const TickType_t xValueOfInsertion = pxNewListItem->xItemValue;
before vTaskStartScheduler() has been called?). before vTaskStartScheduler() has been called?).
**********************************************************************/ **********************************************************************/
for( pxIterator = ( ListItem_t * ) &( pxList->xListEnd ); pxIterator->pxNext->xItemValue <= xValueOfInsertion; pxIterator = pxIterator->pxNext ) /*lint !e826 !e740 !e9087 The mini list structure is used as the list end to save RAM. This is checked and valid. *//*lint !e440 The iterator moves to a different value, not xValueOfInsertion. */ for( pxIterator = &( pxList->xListEnd ); pxIterator->pxNext->xItemValue <= xValueOfInsertion; pxIterator = pxIterator->pxNext ) /*lint !e826 !e740 !e9087 The mini list structure is used as the list end to save RAM. This is checked and valid. *//*lint !e440 The iterator moves to a different value, not xValueOfInsertion. */
{ {
/* There is nothing to do here, just iterating to the wanted /* There is nothing to do here, just iterating to the wanted
insertion position. */ insertion position. */
} }
} }
pxNewListItem->pxNext = pxIterator->pxNext; pxNewListItem->xMiniItem.pxNext = pxIterator->pxNext;
pxNewListItem->pxNext->pxPrevious = pxNewListItem; pxNewListItem->xMiniItem.pxNext->pxPrevious = &pxNewListItem->xMiniItem;
pxNewListItem->pxPrevious = pxIterator; pxNewListItem->xMiniItem.pxPrevious = pxIterator;
pxIterator->pxNext = pxNewListItem; pxIterator->pxNext = &pxNewListItem->xMiniItem;
/* Remember which list the item is in. This allows fast removal of the /* Remember which list the item is in. This allows fast removal of the
item later. */ item later. */
@ -173,16 +173,16 @@ UBaseType_t uxListRemove( ListItem_t * const pxItemToRemove )
item. */ item. */
List_t * const pxList = pxItemToRemove->pxContainer; List_t * const pxList = pxItemToRemove->pxContainer;
pxItemToRemove->pxNext->pxPrevious = pxItemToRemove->pxPrevious; pxItemToRemove->xMiniItem.pxNext->pxPrevious = pxItemToRemove->xMiniItem.pxPrevious;
pxItemToRemove->pxPrevious->pxNext = pxItemToRemove->pxNext; pxItemToRemove->xMiniItem.pxPrevious->pxNext = pxItemToRemove->xMiniItem.pxNext;
/* Only used during decision coverage testing. */ /* Only used during decision coverage testing. */
mtCOVERAGE_TEST_DELAY(); mtCOVERAGE_TEST_DELAY();
/* Make sure the index is left pointing to a valid item. */ /* Make sure the index is left pointing to a valid item. */
if( pxList->pxIndex == pxItemToRemove ) if( pxList->pxIndex == &pxItemToRemove->xMiniItem )
{ {
pxList->pxIndex = pxItemToRemove->pxPrevious; pxList->pxIndex = pxItemToRemove->xMiniItem.pxPrevious;
} }
else else
{ {