From 1ac8caa8d22f3767e84e7be749afbd5ed17a11b4 Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Tue, 20 Mar 2018 16:48:26 +0100 Subject: erts: Fix some zero size sys_memcpy --- erts/emulator/beam/erl_bits.h | 2 +- erts/emulator/beam/sys.h | 4 +--- erts/emulator/hipe/hipe_mode_switch.c | 3 ++- 3 files changed, 4 insertions(+), 5 deletions(-) diff --git a/erts/emulator/beam/erl_bits.h b/erts/emulator/beam/erl_bits.h index b9d141d585..a3816fa820 100644 --- a/erts/emulator/beam/erl_bits.h +++ b/erts/emulator/beam/erl_bits.h @@ -111,7 +111,7 @@ typedef struct erl_bin_match_struct{ #define copy_binary_to_buffer(DstBuffer, DstBufOffset, SrcBuffer, SrcBufferOffset, NumBits) \ do { \ if (BIT_OFFSET(DstBufOffset) == 0 && (SrcBufferOffset == 0) && \ - (BIT_OFFSET(NumBits)==0)) { \ + (BIT_OFFSET(NumBits)==0) && (NumBits != 0)) { \ sys_memcpy(DstBuffer+BYTE_OFFSET(DstBufOffset), \ SrcBuffer, NBYTES(NumBits)); \ } else { \ diff --git a/erts/emulator/beam/sys.h b/erts/emulator/beam/sys.h index 152da8c9e1..c21acadd8d 100644 --- a/erts/emulator/beam/sys.h +++ b/erts/emulator/beam/sys.h @@ -1004,9 +1004,7 @@ erts_refc_read(erts_refc_t *refcp, erts_aint_t min_val) * may seemingly work when the length (if any) is zero; a compiler can take * this as a hint that the passed operand may *never* be NULL and then optimize * based on that information. - * - * (The weird casts in the assertions silence an "always evaluates to true" - * warning when an operand is the address of an lvalue) */ + */ ERTS_GLB_INLINE void *sys_memcpy(void *dest, const void *src, size_t n); ERTS_GLB_INLINE void *sys_memmove(void *dest, const void *src, size_t n); ERTS_GLB_INLINE int sys_memcmp(const void *s1, const void *s2, size_t n); diff --git a/erts/emulator/hipe/hipe_mode_switch.c b/erts/emulator/hipe/hipe_mode_switch.c index 8b497c9970..f2befb07e3 100644 --- a/erts/emulator/hipe/hipe_mode_switch.c +++ b/erts/emulator/hipe/hipe_mode_switch.c @@ -662,7 +662,8 @@ void hipe_inc_nstack(Process *p) Eterm *new_nstack = erts_alloc(ERTS_ALC_T_HIPE_STK, new_size*sizeof(Eterm)); unsigned used_size = p->hipe.nstend - p->hipe.nsp; - sys_memcpy(new_nstack+new_size-used_size, p->hipe.nsp, used_size*sizeof(Eterm)); + if (used_size) + sys_memcpy(new_nstack+new_size-used_size, p->hipe.nsp, used_size*sizeof(Eterm)); if (p->hipe.nstgraylim) p->hipe.nstgraylim = new_nstack + new_size - (p->hipe.nstend - p->hipe.nstgraylim); if (p->hipe.nstblacklim) -- cgit v1.2.3