| @@ -59,10 +59,9 @@ unsafe impl GlobalAlloc for System { |
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} |
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cfg_if::cfg_if! { |
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-// We use posix_memalign wherever possible, but not all targets have that function. |
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+// We use posix_memalign wherever possible, but some targets have very incomplete POSIX coverage |
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+// so we need a fallback for those. |
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if #[cfg(any( |
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- target_os = "redox", |
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- target_os = "espidf", |
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target_os = "horizon", |
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target_os = "vita", |
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))] { |
| @@ -74,12 +73,11 @@ cfg_if::cfg_if! { |
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#[inline] |
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unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 { |
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let mut out = ptr::null_mut(); |
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-// We prefer posix_memalign over aligned_malloc since with aligned_malloc, |
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-// implementations are making almost arbitrary choices for which alignments are |
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-// "supported", making it hard to use. For instance, some implementations require the |
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-// size to be a multiple of the alignment (wasi emmalloc), while others require the |
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-// alignment to be at least the pointer size (Illumos, macOS) -- which may or may not be |
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-// standards-compliant, but that does not help us. |
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+// We prefer posix_memalign over aligned_alloc since it is more widely available, and |
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+// since with aligned_alloc, implementations are making almost arbitrary choices for |
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+// which alignments are "supported", making it hard to use. For instance, some |
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+// implementations require the size to be a multiple of the alignment (wasi emmalloc), |
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+// while others require the alignment to be at least the pointer size (Illumos, macOS). |
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// posix_memalign only has one, clear requirement: that the alignment be a multiple of |
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// `sizeof(void*)`. Since these are all powers of 2, we can just use max. |
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let align = layout.align().max(crate::mem::size_of::<usize>()); |