mirror of
https://github.com/bytecodealliance/wasm-micro-runtime.git
synced 2026-04-18 18:18:44 +00:00
feat(mem-alloc): enhance aligned allocation with metadata handling
This commit is contained in:
liang.he@intel.com
parent
5ac967ca2b
commit
6042a61092
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@ -559,7 +559,7 @@ obj_to_hmu(gc_object_t obj)
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/* Check for aligned allocation magic signature */
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if (gc_is_aligned_allocation(obj)) {
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/* This is an aligned allocation, read offset */
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uint32_t *offset_ptr = (uint32_t *)((char *)obj - 8);
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uint32_t *offset_ptr = ALIGNED_ALLOC_GET_OFFSET_PTR(obj);
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return (hmu_t *)((char *)obj - *offset_ptr);
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}
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@ -581,7 +581,7 @@ gc_alloc_vo_internal(void *vheap, gc_size_t size, const char *file, int line)
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gc_size_t tot_size = 0, tot_size_unaligned;
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/* hmu header + prefix + obj + suffix */
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tot_size_unaligned = HMU_SIZE + OBJ_PREFIX_SIZE + size + OBJ_SUFFIX_SIZE;
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tot_size_unaligned = size + OBJ_EXTRA_SIZE;
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/* aligned size*/
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tot_size = GC_ALIGN_8(tot_size_unaligned);
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if (tot_size < size)
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@ -668,8 +668,7 @@ gc_alloc_vo_aligned_internal(void *vheap, gc_size_t size, gc_size_t alignment,
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return NULL;
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}
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if (size > SIZE_MAX - alignment - HMU_SIZE - OBJ_PREFIX_SIZE
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- OBJ_SUFFIX_SIZE - 8) {
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if (size > SIZE_MAX - GC_ALIGNED_SMALLEST_SIZE(alignment)) {
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/* Would overflow */
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return NULL;
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}
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@ -682,8 +681,8 @@ gc_alloc_vo_aligned_internal(void *vheap, gc_size_t size, gc_size_t alignment,
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#endif
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/* Calculate total size needed */
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tot_size_unaligned =
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HMU_SIZE + OBJ_PREFIX_SIZE + size + OBJ_SUFFIX_SIZE + alignment - 1 + 8;
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tot_size_unaligned = size + OBJ_EXTRA_SIZE + ALIGNED_ALLOC_EXTRA_OVERHEAD
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+ (alignment > 8 ? (alignment - 8) : 8);
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tot_size = GC_ALIGN_8(tot_size_unaligned);
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if (tot_size < size) {
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@ -707,9 +706,10 @@ gc_alloc_vo_aligned_internal(void *vheap, gc_size_t size, gc_size_t alignment,
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/* Get base object pointer */
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base_obj = (gc_uint8 *)hmu + HMU_SIZE + OBJ_PREFIX_SIZE;
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/* Find next aligned address, leaving 8 bytes for metadata */
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aligned_addr = (((uintptr_t)base_obj + 8 + alignment - 1)
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& ~(uintptr_t)(alignment - 1));
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/* Find next aligned address, reserving space for metadata */
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aligned_addr =
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(((uintptr_t)base_obj + ALIGNED_ALLOC_METADATA_SIZE + alignment - 1)
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& ~(uintptr_t)(alignment - 1));
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ret = (gc_object_t)aligned_addr;
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/* Verify we have enough space */
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@ -725,11 +725,11 @@ gc_alloc_vo_aligned_internal(void *vheap, gc_size_t size, gc_size_t alignment,
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alignment_log2++;
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}
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/* Store offset 8 bytes before returned pointer */
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*((uint32_t *)((char *)ret - 8)) = offset;
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/* Store offset before returned pointer */
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*ALIGNED_ALLOC_GET_OFFSET_PTR(ret) = offset;
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/* Store magic with encoded alignment */
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*((uint32_t *)((char *)ret - 4)) =
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*ALIGNED_ALLOC_GET_MAGIC_PTR(ret) =
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ALIGNED_ALLOC_MAGIC_VALUE | alignment_log2;
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/* Initialize HMU */
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@ -86,11 +86,11 @@ hmu_verify(void *vheap, hmu_t *hmu);
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#define GC_MIN_ALIGNMENT 8
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#endif
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#define GC_SMALLEST_SIZE \
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GC_ALIGN_8(HMU_SIZE + OBJ_PREFIX_SIZE + OBJ_SUFFIX_SIZE + 8)
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#define GC_GET_REAL_SIZE(x) \
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GC_ALIGN_8(HMU_SIZE + OBJ_PREFIX_SIZE + OBJ_SUFFIX_SIZE \
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+ (((x) > 8) ? (x) : 8))
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/* Smallest allocation size for normal allocations
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* The +8 ensures minimum allocation size for tree node structure */
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#define GC_SMALLEST_SIZE GC_ALIGN_8(OBJ_EXTRA_SIZE + 8)
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#define GC_GET_REAL_SIZE(x) GC_ALIGN_8(OBJ_EXTRA_SIZE + (((x) > 8) ? (x) : 8))
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/*
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* ============================================================================
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@ -150,13 +150,17 @@ hmu_verify(void *vheap, hmu_t *hmu);
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* ----------------------
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*
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* Low Address High Address
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* ┌─────────────┬──────────┬────────────────┬──────────────┬─────────────┐
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* │ HMU Header │ Padding │ Magic + Offset │ Aligned Data │ Padding │
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* │ (meta) │ (0-align)│ (4 bytes) │ (size) │ (overhead) │
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* └─────────────┴──────────┴────────────────┴──────────────┴─────────────┘
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* ▲ ▲
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* │ │
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* magic_ptr user_ptr (returned, aligned)
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* ┌─────────────┬──────────┬─────────┬─────────┬──────────────┬─────────────┐
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* │ HMU Header │ Padding │ Offset │ Magic │ Aligned Data │ Padding │
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* │ (4 bytes) │(variable)│(4 bytes)│(4 bytes)│ (size) │ (overhead) │
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* └─────────────┴──────────┴─────────┴─────────┴──────────────┴─────────────┘
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* ▲ └────8 bytes────┘ ▲
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* hmu user_ptr (returned, aligned)
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*
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* Padding is variable-length to satisfy alignment constraint:
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* align_up(HMU_SIZE + ALIGNED_ALLOC_METADATA_SIZE, alignment)
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* For alignment >= 12: HMU_SIZE + padding + 8 = alignment
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* For alignment < 12: HMU_SIZE + padding + 8 = round_up(12, alignment)
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*
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* Constraints and Limitations:
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* ----------------------------
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@ -182,10 +186,35 @@ hmu_verify(void *vheap, hmu_t *hmu);
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* void *new_ptr = wasm_runtime_realloc(ptr, 512); // Returns NULL!
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*/
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/* Aligned allocation constants */
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/* Size of offset field before aligned ptr */
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#define ALIGNED_ALLOC_OFFSET_SIZE 4
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/* Size of magic marker before aligned ptr */
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#define ALIGNED_ALLOC_MAGIC_SIZE 4
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/* Total: 8 bytes */
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#define ALIGNED_ALLOC_METADATA_SIZE \
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(ALIGNED_ALLOC_OFFSET_SIZE + ALIGNED_ALLOC_MAGIC_SIZE)
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/* Aligned allocation magic markers */
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#define ALIGNED_ALLOC_MAGIC_MASK 0xFFFF0000
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#define ALIGNED_ALLOC_MAGIC_VALUE 0xA11C0000
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/* Get magic pointer from aligned object pointer */
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#define ALIGNED_ALLOC_GET_MAGIC_PTR(obj) \
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((uint32_t *)((char *)(obj)-ALIGNED_ALLOC_MAGIC_SIZE))
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/* Get offset pointer from aligned object pointer */
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#define ALIGNED_ALLOC_GET_OFFSET_PTR(obj) \
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((uint32_t *)((char *)(obj)-ALIGNED_ALLOC_METADATA_SIZE))
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/* Extra overhead for aligned allocations beyond normal OBJ_EXTRA_SIZE */
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#define ALIGNED_ALLOC_EXTRA_OVERHEAD ALIGNED_ALLOC_METADATA_SIZE
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/* Smallest allocation size for aligned allocations */
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#define GC_ALIGNED_SMALLEST_SIZE(alignment) \
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GC_ALIGN_8(OBJ_EXTRA_SIZE + ALIGNED_ALLOC_METADATA_SIZE \
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+ ((alignment) > 8 ? (alignment - 8) : 8))
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/**
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* Check if a gc_object was allocated with alignment requirements.
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*
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@ -202,7 +231,7 @@ gc_is_aligned_allocation(gc_object_t obj)
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if (!obj)
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return false;
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uint32_t *magic_ptr = (uint32_t *)((char *)obj - 4);
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uint32_t *magic_ptr = ALIGNED_ALLOC_GET_MAGIC_PTR(obj);
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return ((*magic_ptr & ALIGNED_ALLOC_MAGIC_MASK)
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== ALIGNED_ALLOC_MAGIC_VALUE);
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}
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