On Fri, Feb 2, 2018 at 9:53 AM, Eric Botcazou <ebotca...@adacore.com> wrote: >> We currently read and write beyond the builtin jmpbuf on ILP32 targets >> where Pmode == DImode and ptr_mode == SImode. Since the builtin jmpbuf >> is an array of 5 pointers, ptr_mode should be used to save and restore >> frame and program pointers. Since x86 only saves stack pointer in >> stack save area, STACK_SAVEAREA_MODE should be ptr_mode, not Pmode. > > I think that some targets really need Pmode. And the buffer should be able to
Some targets need more than Pmode. ia64/ia64.h has /* We need 32 bytes, so we can save the sp, ar.rnat, ar.bsp, and ar.pfs of the function containing a non-local goto target. */ #define STACK_SAVEAREA_MODE(LEVEL) \ ((LEVEL) == SAVE_NONLOCAL ? OImode : Pmode) > accomodate up to 5 words, see init_eh: > > /* Compute a minimally sized jump buffer. We need room to store at > least 3 pointers - stack pointer, frame pointer and return address. > Plus for some targets we need room for an extra pointer - in the > case of MIPS this is the global pointer. This makes a total of four > pointers, but to be safe we actually allocate room for 5. > > If pointers are smaller than words then we allocate enough room for > 5 words, just in case the backend needs this much room. For more > discussion on this issue see: > http://gcc.gnu.org/ml/gcc-patches/2014-05/msg00313.html. */ > if (POINTER_SIZE > BITS_PER_WORD) > tmp = size_int (5 - 1); > else > tmp = size_int ((5 * BITS_PER_WORD / POINTER_SIZE) - 1); > My only changes STACK_SAVEAREA_MODE for x86. Other targets are unchanged. -- H.J.
