Cheri-research/snmalloc
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Eliminate pointer_cast()

Browse Source 
Since we anticipate address_t not carrying provenance on CHERI, but
rather being vaddr_t there, it doesn't make sense to offer conversion
back to a provenance-carrying pointer.

Thankfully, there is not much to be done here: the uses were few and
could be replaced with the vocabulary of other pointer operations in
ds/address.h
This commit is contained in:
Nathaniel Filardo
2020-05-15 19:32:09 +00:00
parent 79ad6630d3
commit 3f32f37e60
3 changed files with 37 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
src/ds/address.h
View File

@@ -42,16 +42,6 @@ namespace snmalloc
return reinterpret_cast<address_t>(ptr);
}
/**
* Cast from an address back to a pointer of the specified type. All uses of
* this will eventually need auditing for CHERI compatibility.
*/
template<typename T>
inline T* pointer_cast(address_t address)
{
return reinterpret_cast<T*>(address);
}
/**
* Test if a pointer is aligned to a given size, which must be a power of
* two.
@@ -81,7 +71,8 @@ namespace snmalloc
#if __has_builtin(__builtin_align_down)
return static_cast<T*>(__builtin_align_down(p, alignment));
#else
return pointer_cast<T>(bits::align_down(address_cast(p), alignment));
return reinterpret_cast<T*>(
bits::align_down(reinterpret_cast<uintptr_t>(p), alignment));
#endif
}
}
@@ -102,11 +93,29 @@ namespace snmalloc
#if __has_builtin(__builtin_align_up)
return static_cast<T*>(__builtin_align_up(p, alignment));
#else
return pointer_cast<T>(bits::align_up(address_cast(p), alignment));
return reinterpret_cast<T*>(
bits::align_up(reinterpret_cast<uintptr_t>(p), alignment));
#endif
}
}
/**
* Align a pointer down to a dynamically specified granularity, which must be
* a power of two.
*/
template<typename T = void>
SNMALLOC_FAST_PATH T* pointer_align_down(void* p, size_t alignment)
{
SNMALLOC_ASSERT(alignment > 0);
SNMALLOC_ASSERT(bits::next_pow2(alignment) == alignment);
#if __has_builtin(__builtin_align_down)
return static_cast<T*>(__builtin_align_down(p, alignment));
#else
return reinterpret_cast<T*>(
bits::align_down(reinterpret_cast<uintptr_t>(p), alignment));
#endif
}
/**
* Align a pointer up to a dynamically specified granularity, which must
* be a power of two.
@@ -119,7 +128,8 @@ namespace snmalloc
#if __has_builtin(__builtin_align_up)
return static_cast<T*>(__builtin_align_up(p, alignment));
#else
return pointer_cast<T>(bits::align_up(address_cast(p), alignment));
return reinterpret_cast<T*>(
bits::align_up(reinterpret_cast<uintptr_t>(p), alignment));
#endif
}