/** This global references the unaligned memory address that was malloced for the snapshotting heap */
void * basemySpace = NULL;
-/** Adding the fix for not able to allocate through a reimplemented calloc at the beginning before instantiating our allocator
-A bit circumspect about adding an sbrk. linux docs say to avoid using it... */
+/** Bootstrap allocation. Problem is that the dynamic linker calls
+ * require calloc to work and calloc requires the dynamic linker to
+ * work. */
+
+#define BOOTSTRAPBYTES 4096
+char bootstrapmemory[BOOTSTRAPBYTES];
+size_t offset=0;
+
void * HandleEarlyAllocationRequest( size_t sz ){
- if( 0 == mySpace ){
- void * returnAddress = sbrk( sz );
- if( nextRequest >= REQUESTS_BEFORE_ALLOC ){
- exit( EXIT_FAILURE );
- }
- allocatedReqs[ nextRequest++ ] = ( size_t )returnAddress;
- return returnAddress;
+ /*Align to 8 byte boundary*/
+ sz=(sz+7)&~7;
+
+ if (sz > (BOOTSTRAPBYTES-offset)) {
+ printf("OUT OF BOOTSTRAP MEMORY\n");
+ exit(EXIT_FAILURE);
}
- return NULL;
+
+ void * pointer= (void *) & bootstrapmemory[offset];
+ offset+=sz;
+ return pointer;
}
-/** The fact that I am not expecting more than a handful requests is implicit in my not using a binary search here*/
+/** Check whether this is bootstrapped memory that we should not
+ free. */
+
bool DontFree( void * ptr ){
- if( howManyFreed == nextRequest ) return false; //a minor optimization to reduce the number of instructions executed on each free call....
- if( NULL == ptr ) return true;
- for( int i = nextRequest - 1; i >= 0; --i ){
- if( allocatedReqs[ i ] == ( size_t )ptr ) {
- ++howManyFreed;
- return true;
- }
- }
- return false;
+ return (ptr>=(&bootstrapmemory[0])&&ptr<(&bootstrapmemory[BOOTSTRAPBYTES]));
}
/** Snapshotting malloc implementation for user programs. */
void *malloc( size_t size ) {
- void * earlyReq = HandleEarlyAllocationRequest( size );
- if( earlyReq ) return earlyReq;
- return mspace_malloc( mySpace, size );
+ if (mySpace)
+ return mspace_malloc( mySpace, size );
+ else
+ return HandleEarlyAllocationRequest( size );
}
/** Snapshotting free implementation for user programs. */
/** Snapshotting calloc implementation for user programs. */
void * calloc( size_t num, size_t size ){
- void * earlyReq = HandleEarlyAllocationRequest( size * num );
- if( earlyReq ) {
- std::memset( earlyReq, 0, size * num );
- return earlyReq;
+ if (mySpace)
+ return mspace_calloc( mySpace, num, size );
+ else {
+ void *tmp=HandleEarlyAllocationRequest( size * num );
+ std::memset( tmp, 0, size * num );
+ return tmp;
}
- return mspace_calloc( mySpace, num, size );
}
/** Snapshotting new operator for user programs. */