runtime (gc_blocks.go): reverse-align the heap start#5142
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niaow wants to merge 1 commit intotinygo-org:devfrom
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runtime (gc_blocks.go): reverse-align the heap start#5142niaow wants to merge 1 commit intotinygo-org:devfrom
niaow wants to merge 1 commit intotinygo-org:devfrom
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This shifts the whole heap forwards by the difference in alignment instead of padding each objHeader. This significantly reduces the per-alloc overhead on many platforms: - rv32, 386, wasm: conservative 16B -> 4B, precise 16B -> 8B - arm, mips: conservative 8B -> 4B, precise unchanged - arm64, amd64: conservative 16B -> 8B, precise unchanged - avr: unchanged Unfortunately, LLVM cannot fuse the offset into the immediate address on some platforms. It instead just adds the diffence on every accesss.
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This shifts the whole heap forwards by the difference in alignment instead of padding each objHeader. This significantly reduces the per-alloc overhead on many platforms:
Unfortunately, LLVM cannot fuse the offset into the immediate address on some platforms. It instead just adds the diffence on every accesss.