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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 )
{
ListItem_t *pxListItem, *pxNext;
ListItem_t const *pxListEnd;
MiniListItem_t *pxListItem, *pxNext;
MiniListItem_t const *pxListEnd;
List_t const * pxList;
EventBits_t uxBitsToClear = 0, uxBitsWaitedFor, uxControlBits;
EventGroup_t *pxEventBits = xEventGroup;
@ -545,7 +545,7 @@ BaseType_t xMatchFound = pdFALSE;
while( pxListItem != pxListEnd )
{
pxNext = listGET_NEXT( pxListItem );
uxBitsWaitedFor = listGET_LIST_ITEM_VALUE( pxListItem );
uxBitsWaitedFor = listGET_LIST_ITEM_VALUE( ( ListItem_t * ) pxListItem );
xMatchFound = pdFALSE;
/* 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
that is was unblocked due to its required bits matching, rather
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
@ -624,7 +624,7 @@ const List_t *pxTasksWaitingForBits = &( pxEventBits->xTasksWaitingForBits );
/* Unblock the task, returning 0 as the event list is being deleted
and cannot therefore have any bits set. */
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 ) )

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.
*/
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
{
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;
struct xLIST_ITEM * configLIST_VOLATILE pxNext;
struct xLIST_ITEM * configLIST_VOLATILE pxPrevious;
struct xMINI_LIST_ITEM * configLIST_VOLATILE pxNext;
struct xMINI_LIST_ITEM * configLIST_VOLATILE pxPrevious;
};
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.
*/
@ -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. */
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. */
listSECOND_LIST_INTEGRITY_CHECK_VALUE /*< Set to a known value if configUSE_LIST_DATA_INTEGRITY_CHECK_BYTES is set to 1. */
} List_t;
@ -195,7 +193,7 @@ typedef struct xLIST
* \page listSET_LIST_ITEM_VALUE listSET_LIST_ITEM_VALUE
* \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
@ -205,7 +203,7 @@ typedef struct xLIST
* \page listGET_LIST_ITEM_VALUE listGET_LIST_ITEM_VALUE
* \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
@ -238,7 +236,7 @@ typedef struct xLIST
* \page listGET_END_MARKER listGET_END_MARKER
* \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
@ -284,7 +282,7 @@ List_t * const pxConstList = ( pxList ); \
{ \
( 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
* \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

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
end of the list. To initialise the list the list end is inserted
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
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
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.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.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 = &( 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;
@ -73,7 +73,7 @@ void vListInitialiseItem( ListItem_t * const pxItem )
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
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,
makes the new list item the last item to be removed by a call to
listGET_OWNER_OF_NEXT_ENTRY(). */
pxNewListItem->pxNext = pxIndex;
pxNewListItem->pxPrevious = pxIndex->pxPrevious;
pxNewListItem->xMiniItem.pxNext = pxIndex;
pxNewListItem->xMiniItem.pxPrevious = pxIndex->pxPrevious;
/* Only used during decision coverage testing. */
mtCOVERAGE_TEST_DELAY();
pxIndex->pxPrevious->pxNext = pxNewListItem;
pxIndex->pxPrevious = pxNewListItem;
pxIndex->pxPrevious->pxNext = &pxNewListItem->xMiniItem;
pxIndex->pxPrevious = &pxNewListItem->xMiniItem;
/* Remember which list the item is in. */
pxNewListItem->pxContainer = pxList;
@ -102,8 +102,8 @@ ListItem_t * const pxIndex = pxList->pxIndex;
void vListInsert( List_t * const pxList, ListItem_t * const pxNewListItem )
{
ListItem_t *pxIterator;
const TickType_t xValueOfInsertion = pxNewListItem->xItemValue;
MiniListItem_t *pxIterator;
const TickType_t xValueOfInsertion = pxNewListItem->xMiniItem.xItemValue;
/* Only effective when configASSERT() is also defined, these tests may 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?).
**********************************************************************/
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
insertion position. */
}
}
pxNewListItem->pxNext = pxIterator->pxNext;
pxNewListItem->pxNext->pxPrevious = pxNewListItem;
pxNewListItem->pxPrevious = pxIterator;
pxIterator->pxNext = pxNewListItem;
pxNewListItem->xMiniItem.pxNext = pxIterator->pxNext;
pxNewListItem->xMiniItem.pxNext->pxPrevious = &pxNewListItem->xMiniItem;
pxNewListItem->xMiniItem.pxPrevious = pxIterator;
pxIterator->pxNext = &pxNewListItem->xMiniItem;
/* Remember which list the item is in. This allows fast removal of the
item later. */
@ -173,16 +173,16 @@ UBaseType_t uxListRemove( ListItem_t * const pxItemToRemove )
item. */
List_t * const pxList = pxItemToRemove->pxContainer;
pxItemToRemove->pxNext->pxPrevious = pxItemToRemove->pxPrevious;
pxItemToRemove->pxPrevious->pxNext = pxItemToRemove->pxNext;
pxItemToRemove->xMiniItem.pxNext->pxPrevious = pxItemToRemove->xMiniItem.pxPrevious;
pxItemToRemove->xMiniItem.pxPrevious->pxNext = pxItemToRemove->xMiniItem.pxNext;
/* Only used during decision coverage testing. */
mtCOVERAGE_TEST_DELAY();
/* 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
{