program-entrypoint: Add a BumpAllocator constructor - #284
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#### Problem The current version of program-entrypoint doesn't work because the allocator can't be instantiated in the macros. The start and len fields are private, and so can't be written to in the macro, which exists in the scope of the program. #### Summary of changes Add a new constructor that can be used by the macro.
febo
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Aug 13, 2025
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| static A: $crate::BumpAllocator = $crate::BumpAllocator::new_with_fixed_address_range( | ||
| $crate::HEAP_START_ADDRESS as usize, | ||
| $crate::HEAP_LENGTH, | ||
| ); |
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We might need to wrap this in an unsafe block:
Suggested change
| static A: $crate::BumpAllocator = $crate::BumpAllocator::new_with_fixed_address_range( | |
| $crate::HEAP_START_ADDRESS as usize, | |
| $crate::HEAP_LENGTH, | |
| ); | |
| static A: $crate::BumpAllocator = unsafe { | |
| $crate::BumpAllocator::new_with_fixed_address_range( | |
| $crate::HEAP_START_ADDRESS as usize, | |
| $crate::HEAP_LENGTH, | |
| ) | |
| }; |
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You're totally right! I also had to make the function const
febo
reviewed
Aug 13, 2025
| /// | ||
| /// For Solana on-chain programs, a certain address range is reserved, so | ||
| /// the allocator can be given those addresses. | ||
| pub const unsafe fn new_with_fixed_address_range(start: usize, len: usize) -> Self { |
Contributor
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Maybe we can drop the "new" from the name, like the one in Vec type:
Suggested change
| pub const unsafe fn new_with_fixed_address_range(start: usize, len: usize) -> Self { | |
| pub const unsafe fn with_fixed_address_range(start: usize, len: usize) -> Self { |
febo
previously approved these changes
Aug 13, 2025
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febo
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Looks great! Just left a comment about the name, but that is cosmetic.
febo
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Sep 21, 2025
* program-entrypoint: Add a BumpAllocator constructor #### Problem The current version of program-entrypoint doesn't work because the allocator can't be instantiated in the macros. The start and len fields are private, and so can't be written to in the macro, which exists in the scope of the program. #### Summary of changes Add a new constructor that can be used by the macro. * Make function const, call from unsafe block * Rename
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Problem
The current version of program-entrypoint doesn't work because the allocator can't be instantiated in the macros. The start and len fields are private, and so can't be written to in the macro, which exists in the scope of the program.
Summary of changes
Add a new constructor that can be used by the macro.