On Mon, 22 Sep 2014, Uros Bizjak wrote:
> On Mon, Sep 22, 2014 at 5:30 PM, Ilya Enkovich <enkovich....@gmail.com> wrote:
> > On 19 Sep 18:21, Uros Bizjak wrote:
> >> On Fri, Sep 19, 2014 at 2:53 PM, Ilya Enkovich <enkovich....@gmail.com>
> >> wrote:
> >>
> >> >> > This patch adds i386 target hooks for Pointer Bounds Checker.
> >>
> >> > New version with fixes and better documentation for ix86_load_bounds and
> >> > ix86_store_bounds is below.
> >>
> >> > +/* Expand pass uses this hook to load bounds for function parameter
> >> > + PTR passed in SLOT in case its bounds are not passed in a register.
> >> > +
> >> > + If SLOT is a memory, then bounds are loaded as for regular pointer
> >> > + loaded from memory. PTR may be NULL in case SLOT is a memory.
> >> > + In such case value of PTR (if required) may be loaded from SLOT.
> >> > +
> >> > + If SLOT is NULL or a register then SLOT_NO is an integer constant
> >> > + holding number of the target dependent special slot which should be
> >> > + used to obtain bounds.
> >> > +
> >> > + Return loaded bounds. */
> >>
> >> OK, I hope I understand this target-handling of SLOT_NO. Can you
> >> please clarify when SLOT is a register?
> >
> > For functions with more than four pointers passed in registers we do not
> > have enough bound registers to pass bounds. These hooks are called then
> > with SLOT set to register used to pass pointer
> >
> >>
> >> I propose to write this function in the following (hopefully equivalent)
> >> way:
> >
> > Since addr computation is very similar for both loading and storing (the
> > only difference is usage of either arg_pointer_rtx or stack_pointer_rtx) I
> > decided additionally move it into a separate function. This should make
> > functions simplier for understanding.
>
> LGTM, just add the explanation when NULL is returned.
>
> > Here is an updated patch version.
> >
> > Thanks,
> > Ilya
> > --
> > 2014-09-22 Ilya Enkovich <ilya.enkov...@intel.com>
> >
> > * config/i386/i386.c: Include tree-iterator.h.
> > (ix86_function_value_bounds): New.
> > (ix86_builtin_mpx_function): New.
> > (ix86_get_arg_address_for_bt): New.
> > (ix86_load_bounds): New.
> > (ix86_store_bounds): New.
> > (ix86_load_returned_bounds): New.
> > (ix86_store_returned_bounds): New.
> > (ix86_mpx_bound_mode): New.
> > (ix86_make_bounds_constant): New.
> > (ix86_initialize_bounds):
> > (TARGET_LOAD_BOUNDS_FOR_ARG): New.
> > (TARGET_STORE_BOUNDS_FOR_ARG): New.
> > (TARGET_LOAD_RETURNED_BOUNDS): New.
> > (TARGET_STORE_RETURNED_BOUNDS): New.
> > (TARGET_CHKP_BOUND_MODE): New.
> > (TARGET_BUILTIN_CHKP_FUNCTION): New.
> > (TARGET_CHKP_FUNCTION_VALUE_BOUNDS): New.
> > (TARGET_CHKP_MAKE_BOUNDS_CONSTANT): New.
> > (TARGET_CHKP_INITIALIZE_BOUNDS): New.
>
> Assuming that tree part is OK (I have CC'd Richi for his opinion), the
> patch is OK.
>
> Thanks,
> Uros.
>
> >
> >
> > diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> > index d493983..8a3f577 100644
> > --- a/gcc/config/i386/i386.c
> > +++ b/gcc/config/i386/i386.c
> > @@ -85,6 +85,7 @@ along with GCC; see the file COPYING3. If not see
> > #include "tree-vectorizer.h"
> > #include "shrink-wrap.h"
> > #include "builtins.h"
> > +#include "tree-iterator.h"
> > #include "tree-chkp.h"
> > #include "rtl-chkp.h"
> >
> > @@ -8001,6 +8002,39 @@ ix86_function_value (const_tree valtype, const_tree
> > fntype_or_decl, bool)
> > return ix86_function_value_1 (valtype, fntype_or_decl, orig_mode, mode);
> > }
> >
The function misses a comment.
> > +static rtx
> > +ix86_function_value_bounds (const_tree valtype,
> > + const_tree fntype_or_decl ATTRIBUTE_UNUSED,
> > + bool outgoing ATTRIBUTE_UNUSED)
> > +{
> > + rtx res = NULL_RTX;
> > +
> > + if (BOUNDED_TYPE_P (valtype))
> > + res = gen_rtx_REG (BNDmode, FIRST_BND_REG);
> > + else if (chkp_type_has_pointer (valtype))
> > + {
> > + bitmap slots = chkp_find_bound_slots (valtype);
> > + rtx bounds[2];
> > + bitmap_iterator bi;
> > + unsigned i, bnd_no = 0;
> > +
> > + EXECUTE_IF_SET_IN_BITMAP (slots, 0, i, bi)
> > + {
> > + rtx reg = gen_rtx_REG (BNDmode, FIRST_BND_REG + bnd_no);
> > + rtx offs = GEN_INT (i * POINTER_SIZE / BITS_PER_UNIT);
> > + gcc_assert (bnd_no < 2);
> > + bounds[bnd_no++] = gen_rtx_EXPR_LIST (VOIDmode, reg, offs);
> > + }
> > +
> > + res = gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (bnd_no, bounds));
> > + BITMAP_FREE (slots);
> > + }
> > + else
> > + res = NULL_RTX;
> > +
> > + return res;
> > +}
> > +
> > /* Pointer function arguments and return values are promoted to
> > word_mode. */
> >
> > @@ -36754,6 +36788,193 @@ static tree ix86_get_builtin (enum ix86_builtins
> > code)
> > return NULL_TREE;
> > }
> >
> > +/* Return function decl for target specific builtin
> > + for given MPX builtin passed i FCODE. */
> > +static tree
> > +ix86_builtin_mpx_function (unsigned fcode)
> > +{
> > + switch (fcode)
> > + {
> > + case BUILT_IN_CHKP_BNDMK:
> > + return ix86_builtins[IX86_BUILTIN_BNDMK];
> > +
> > + case BUILT_IN_CHKP_BNDSTX:
> > + return ix86_builtins[IX86_BUILTIN_BNDSTX];
> > +
> > + case BUILT_IN_CHKP_BNDLDX:
> > + return ix86_builtins[IX86_BUILTIN_BNDLDX];
> > +
> > + case BUILT_IN_CHKP_BNDCL:
> > + return ix86_builtins[IX86_BUILTIN_BNDCL];
> > +
> > + case BUILT_IN_CHKP_BNDCU:
> > + return ix86_builtins[IX86_BUILTIN_BNDCU];
> > +
> > + case BUILT_IN_CHKP_BNDRET:
> > + return ix86_builtins[IX86_BUILTIN_BNDRET];
> > +
> > + case BUILT_IN_CHKP_INTERSECT:
> > + return ix86_builtins[IX86_BUILTIN_BNDINT];
> > +
> > + case BUILT_IN_CHKP_NARROW:
> > + return ix86_builtins[IX86_BUILTIN_BNDNARROW];
> > +
> > + case BUILT_IN_CHKP_SIZEOF:
> > + return ix86_builtins[IX86_BUILTIN_SIZEOF];
> > +
> > + case BUILT_IN_CHKP_EXTRACT_LOWER:
> > + return ix86_builtins[IX86_BUILTIN_BNDLOWER];
> > +
> > + case BUILT_IN_CHKP_EXTRACT_UPPER:
> > + return ix86_builtins[IX86_BUILTIN_BNDUPPER];
> > +
> > + default:
> > + return NULL_TREE;
> > + }
> > +
> > + gcc_unreachable ();
> > +}
> > +
> > +/* Helper function for ix86_load_bounds and ix86_store_bounds.
> > +
> > + Return an address to be used to load/store bounds for pointer
> > + passed in SLOT.
> > +
> > + SLOT_NO is an integer constant holding number of a target
> > + dependent special slot to be used in case SLOT is not a memory.
> > +
> > + SPECIAL_BASE is a pointer to be used as a base of fake address
> > + to access special slots in Bounds Table. SPECIAL_BASE[-1],
> > + SPECIAL_BASE[-2] etc. will be used as fake pointer locations. */
> > +
> > +static rtx
> > +ix86_get_arg_address_for_bt (rtx slot, rtx slot_no, rtx special_base)
> > +{
> > + rtx addr = NULL;
> > +
> > + /* NULL slot means we pass bounds for pointer not passed to the
> > + function at all. Register slot means we pass pointer in a
> > + register. In both these cases bounds are passed via Bounds
> > + Table. Since we do not have actual pointer stored in memory,
> > + we have to use fake addresses to access Bounds Table. We
> > + start with (special_base - sizeof (void*)) and decrease this
> > + address by pointer size to get addresses for other slots. */
> > + if (!slot || REG_P (slot))
> > + {
> > + gcc_assert (CONST_INT_P (slot_no));
> > + addr = plus_constant (Pmode, special_base,
> > + -(INTVAL (slot_no) + 1) * GET_MODE_SIZE
> > (Pmode));
> > + }
> > + /* If pointer is passed in a memory then its address is used to
> > + access Bounds Table. */
> > + else if (MEM_P (slot))
> > + {
> > + addr = XEXP (slot, 0);
> > + if (!register_operand (addr, Pmode))
> > + addr = copy_addr_to_reg (addr);
> > + }
> > + else
> > + gcc_unreachable ();
> > +
> > + return addr;
> > +}
> > +
> > +/* Expand pass uses this hook to load bounds for function parameter
> > + PTR passed in SLOT in case its bounds are not passed in a register.
> > +
> > + If SLOT is a memory, then bounds are loaded as for regular pointer
> > + loaded from memory. PTR may be NULL in case SLOT is a memory.
> > + In such case value of PTR (if required) may be loaded from SLOT.
> > +
> > + If SLOT is NULL or a register then SLOT_NO is an integer constant
> > + holding number of the target dependent special slot which should be
> > + used to obtain bounds.
> > +
> > + Return loaded bounds. */
> > +
> > +static rtx
> > +ix86_load_bounds (rtx slot, rtx ptr, rtx slot_no)
> > +{
> > + rtx reg = gen_reg_rtx (BNDmode);
> > + rtx addr;
> > +
> > + /* Get address to be used to access Bounds Table. Special slots start
> > + at the location of return address of the current function. */
> > + addr = ix86_get_arg_address_for_bt (slot, slot_no, arg_pointer_rtx);
> > +
> > + /* Load pointer value from a memory if we don't have it. */
> > + if (!ptr)
> > + {
> > + gcc_assert (MEM_P (slot));
> > + ptr = copy_addr_to_reg (slot);
> > + }
> > +
> > + emit_insn (BNDmode == BND64mode
> > + ? gen_bnd64_ldx (reg, addr, ptr)
> > + : gen_bnd32_ldx (reg, addr, ptr));
> > +
> > + return reg;
> > +}
> > +
> > +/* Expand pass uses this hook to store BOUNDS for call argument PTR
> > + passed in SLOT in case BOUNDS are not passed in a register.
> > +
> > + If SLOT is a memory, then BOUNDS are stored as for regular pointer
> > + stored in memory. PTR may be NULL in case SLOT is a memory.
> > + In such case value of PTR (if required) may be loaded from SLOT.
> > +
> > + If SLOT is NULL or a register then SLOT_NO is an integer constant
> > + holding number of the target dependent special slot which should be
> > + used to store BOUNDS. */
> > +
> > +static void
> > +ix86_store_bounds (rtx ptr, rtx slot, rtx bounds, rtx slot_no)
> > +{
> > + rtx addr;
> > +
> > + /* Get address to be used to access Bounds Table. Special slots start
> > + at the location of return address of a called function. */
> > + addr = ix86_get_arg_address_for_bt (slot, slot_no, stack_pointer_rtx);
> > +
> > + /* Load pointer value from a memory if we don't have it. */
> > + if (!ptr)
> > + {
> > + gcc_assert (MEM_P (slot));
> > + ptr = copy_addr_to_reg (slot);
> > + }
> > +
> > + gcc_assert (POINTER_BOUNDS_MODE_P (GET_MODE (bounds)));
> > + if (!register_operand (bounds, BNDmode))
> > + bounds = copy_to_mode_reg (BNDmode, bounds);
> > +
> > + emit_insn (BNDmode == BND64mode
> > + ? gen_bnd64_stx (addr, ptr, bounds)
> > + : gen_bnd32_stx (addr, ptr, bounds));
> > +}
> > +
> > +/* Load and return bounds returned by function in SLOT. */
> > +
> > +static rtx
> > +ix86_load_returned_bounds (rtx slot)
> > +{
> > + rtx res;
> > +
> > + gcc_assert (REG_P (slot));
> > + res = gen_reg_rtx (BNDmode);
> > + emit_move_insn (res, slot);
> > +
> > + return res;
> > +}
> > +
> > +/* Store BOUNDS returned by function into SLOT. */
> > +
> > +static void
> > +ix86_store_returned_bounds (rtx slot, rtx bounds)
> > +{
> > + gcc_assert (REG_P (slot));
> > + emit_move_insn (slot, bounds);
> > +}
> > +
> > /* Returns a function decl for a vectorized version of the builtin function
> > with builtin function code FN and the result vector type TYPE, or
> > NULL_TREE
> > if it is not available. */
> > @@ -47480,6 +47701,61 @@ ix86_atomic_assign_expand_fenv (tree *hold, tree
> > *clear, tree *update)
> > atomic_feraiseexcept_call);
> > }
> >
Function misses a comment.
> > +static enum machine_mode
> > +ix86_mpx_bound_mode ()
> > +{
> > + /* Do not support pointer checker if MPX
> > + is not enabled. */
> > + if (!TARGET_MPX)
> > + {
> > + if (flag_check_pointer_bounds)
> > + warning (0, "Pointer Checker requires MPX support on this target."
> > + " Use -mmpx options to enable MPX.");
> > + return VOIDmode;
> > + }
> > +
> > + return BNDmode;
> > +}
> > +
Likewise.
> > +static tree
> > +ix86_make_bounds_constant (HOST_WIDE_INT lb, HOST_WIDE_INT ub)
> > +{
> > + tree low = lb ? build_minus_one_cst (pointer_sized_int_node)
> > + : build_zero_cst (pointer_sized_int_node);
> > + tree high = ub ? build_zero_cst (pointer_sized_int_node)
> > + : build_minus_one_cst (pointer_sized_int_node);
> > +
> > + /* This function is supposed to be used to create zero and
> > + none bounds only. */
> > + gcc_assert (lb == 0 || lb == -1);
> > + gcc_assert (ub == 0 || ub == -1);
> > +
> > + return build_complex (NULL, low, high);
> > +}
> > +
Likewise.
> > +static int
> > +ix86_initialize_bounds (tree var, tree lb, tree ub, tree *stmts)
> > +{
> > + tree size_ptr = build_pointer_type (size_type_node);
> > + tree lhs, modify, var_p;
> > +
> > + ub = build1 (BIT_NOT_EXPR, size_type_node, ub);
> > + var_p = build1 (CONVERT_EXPR, size_ptr,
> > + build_fold_addr_expr (var));
Please use fold_convert (size_ptr, build_fold_addr_expr (var)).
Is 'var' always accessed via a size_t effective type? Watch out
for TBAA issues if not. (if it is, why is 'var' not of type
size_t or size_t[]?)
> > + lhs = build1 (INDIRECT_REF, size_type_node, var_p);
> > + modify = build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, lb);
> > + append_to_statement_list (modify, stmts);
> > +
> > + lhs = build1 (INDIRECT_REF, size_type_node,
> > + build2 (POINTER_PLUS_EXPR, size_ptr, var_p,
> > + TYPE_SIZE_UNIT (size_type_node)));
> > + modify = build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, ub);
> > + append_to_statement_list (modify, stmts);
This was used from inside the gimplifier? Thus this is why you
build GENERIC here and not GIMPLE?
Didn't spot any other "tree" stuff.
Richard.
> > + return 2;
> > +}
> > +
> > /* Initialize the GCC target structure. */
> > #undef TARGET_RETURN_IN_MEMORY
> > #define TARGET_RETURN_IN_MEMORY ix86_return_in_memory
> > @@ -47897,6 +48173,33 @@ ix86_atomic_assign_expand_fenv (tree *hold, tree
> > *clear, tree *update)
> > #undef TARGET_CALL_FUSAGE_CONTAINS_NON_CALLEE_CLOBBERS
> > #define TARGET_CALL_FUSAGE_CONTAINS_NON_CALLEE_CLOBBERS true
> >
> > +#undef TARGET_LOAD_BOUNDS_FOR_ARG
> > +#define TARGET_LOAD_BOUNDS_FOR_ARG ix86_load_bounds
> > +
> > +#undef TARGET_STORE_BOUNDS_FOR_ARG
> > +#define TARGET_STORE_BOUNDS_FOR_ARG ix86_store_bounds
> > +
> > +#undef TARGET_LOAD_RETURNED_BOUNDS
> > +#define TARGET_LOAD_RETURNED_BOUNDS ix86_load_returned_bounds
> > +
> > +#undef TARGET_STORE_RETURNED_BOUNDS
> > +#define TARGET_STORE_RETURNED_BOUNDS ix86_store_returned_bounds
> > +
> > +#undef TARGET_CHKP_BOUND_MODE
> > +#define TARGET_CHKP_BOUND_MODE ix86_mpx_bound_mode
> > +
> > +#undef TARGET_BUILTIN_CHKP_FUNCTION
> > +#define TARGET_BUILTIN_CHKP_FUNCTION ix86_builtin_mpx_function
> > +
> > +#undef TARGET_CHKP_FUNCTION_VALUE_BOUNDS
> > +#define TARGET_CHKP_FUNCTION_VALUE_BOUNDS ix86_function_value_bounds
> > +
> > +#undef TARGET_CHKP_MAKE_BOUNDS_CONSTANT
> > +#define TARGET_CHKP_MAKE_BOUNDS_CONSTANT ix86_make_bounds_constant
> > +
> > +#undef TARGET_CHKP_INITIALIZE_BOUNDS
> > +#define TARGET_CHKP_INITIALIZE_BOUNDS ix86_initialize_bounds
> > +
> > struct gcc_target targetm = TARGET_INITIALIZER;
> >
> > #include "gt-i386.h"
>
>
--
Richard Biener <rguent...@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
GF: Jeff Hawn, Jennifer Guild, Felix Imend"orffer
