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| author | Dana Robinson <43805+derobins@users.noreply.github.com> | 2023-06-06 13:44:33 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2023-06-06 13:44:33 (GMT) |
| commit | 4c57a5b06417e823eef153ae306a6ce06bd907ee (patch) | |
| tree | dc0784d24d72b44e4b25797bec8f000496c9886f /src/H5Tconv.c | |
| parent | b5b1f4c7dfcc4a40af7c6c8ab1c89e49054f33c6 (diff) | |
| download | hdf5-4c57a5b06417e823eef153ae306a6ce06bd907ee.zip hdf5-4c57a5b06417e823eef153ae306a6ce06bd907ee.tar.gz hdf5-4c57a5b06417e823eef153ae306a6ce06bd907ee.tar.bz2 | |
Bring key changesets from develop (#3052)
* Bump GitHub action macOS version to 13 (#2999, #3009)
* Bump GitHub action gcc/g++/gfortran version to 12 (#3015)
* Bump Autoconf version to 2.71 (#2944)
* Fix missing h5_reset() calls in accum test (#3001)
* Only run ttsafe in GitHub thread-safe actions (#2777)
* Fix Java debug asserts on Windows (#3012)
* Fix long double dt_arith bug on macOS (#3038)
Diffstat (limited to 'src/H5Tconv.c')
| -rw-r--r-- | src/H5Tconv.c | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/src/H5Tconv.c b/src/H5Tconv.c index 5deae85..f6ab0d7 100644 --- a/src/H5Tconv.c +++ b/src/H5Tconv.c @@ -887,7 +887,17 @@ done: /* Macro defining action on source data which needs to be aligned (before main action) */ #define H5T_CONV_LOOP_PRE_SALIGN(ST) \ { \ - H5MM_memcpy(&src_aligned, src, sizeof(ST)); \ + /* The uint8_t * cast is required to avoid tripping over undefined behavior. \ + * \ + * The typed pointer arrives via a void pointer, which may have any alignment. \ + * We then cast it to a pointer to a type that is assumed to be aligned, which \ + * is undefined behavior (section 6.3.2.3 paragraph 7 of the C99 standard). \ + * In the past this hasn't caused many problems, but in some cases (e.g. \ + * converting long doubles on macOS), an optimizing compiler might do the \ + * wrong thing (in the macOS case, the conversion uses SSE, which has stricter \ + * requirements about alignment). \ + */ \ + H5MM_memcpy(&src_aligned, (const uint8_t *)src, sizeof(ST)); \ } /* Macro defining action on source data which doesn't need to be aligned (before main action) */ @@ -919,7 +929,17 @@ done: /* Macro defining action on destination data which needs to be aligned (after main action) */ #define H5T_CONV_LOOP_POST_DALIGN(DT) \ { \ - H5MM_memcpy(dst, &dst_aligned, sizeof(DT)); \ + /* The uint8_t * cast is required to avoid tripping over undefined behavior. \ + * \ + * The typed pointer arrives via a void pointer, which may have any alignment. \ + * We then cast it to a pointer to a type that is assumed to be aligned, which \ + * is undefined behavior (section 6.3.2.3 paragraph 7 of the C99 standard). \ + * In the past this hasn't caused many problems, but in some cases (e.g. \ + * converting long doubles on macOS), an optimizing compiler might do the \ + * wrong thing (in the macOS case, the conversion uses SSE, which has stricter \ + * requirements about alignment). \ + */ \ + H5MM_memcpy((uint8_t *)dst, &dst_aligned, sizeof(DT)); \ } /* Macro defining action on destination data which doesn't need to be aligned (after main action) */ |