/* A pass for lowering trees to RTL.
- Copyright (C) 2004 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005 Free Software Foundation, Inc.
This file is part of GCC.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to
-the Free Software Foundation, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA. */
+the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA. */
#include "config.h"
#include "system.h"
#include "tree-pass.h"
#include "except.h"
#include "flags.h"
+#include "diagnostic.h"
+#include "toplev.h"
+#include "debug.h"
+#include "params.h"
+
+/* Verify that there is exactly single jump instruction since last and attach
+ REG_BR_PROB note specifying probability.
+ ??? We really ought to pass the probability down to RTL expanders and let it
+ re-distribute it when the conditional expands into multiple conditionals.
+ This is however difficult to do. */
+static void
+add_reg_br_prob_note (rtx last, int probability)
+{
+ if (profile_status == PROFILE_ABSENT)
+ return;
+ for (last = NEXT_INSN (last); last && NEXT_INSN (last); last = NEXT_INSN (last))
+ if (JUMP_P (last))
+ {
+ /* It is common to emit condjump-around-jump sequence when we don't know
+ how to reverse the conditional. Special case this. */
+ if (!any_condjump_p (last)
+ || !JUMP_P (NEXT_INSN (last))
+ || !simplejump_p (NEXT_INSN (last))
+ || !BARRIER_P (NEXT_INSN (NEXT_INSN (last)))
+ || !LABEL_P (NEXT_INSN (NEXT_INSN (NEXT_INSN (last))))
+ || NEXT_INSN (NEXT_INSN (NEXT_INSN (NEXT_INSN (last)))))
+ goto failed;
+ gcc_assert (!find_reg_note (last, REG_BR_PROB, 0));
+ REG_NOTES (last)
+ = gen_rtx_EXPR_LIST (REG_BR_PROB,
+ GEN_INT (REG_BR_PROB_BASE - probability),
+ REG_NOTES (last));
+ return;
+ }
+ if (!last || !JUMP_P (last) || !any_condjump_p (last))
+ goto failed;
+ gcc_assert (!find_reg_note (last, REG_BR_PROB, 0));
+ REG_NOTES (last)
+ = gen_rtx_EXPR_LIST (REG_BR_PROB,
+ GEN_INT (probability), REG_NOTES (last));
+ return;
+failed:
+ if (dump_file)
+ fprintf (dump_file, "Failed to add probability note\n");
+}
+
+
+#ifndef LOCAL_ALIGNMENT
+#define LOCAL_ALIGNMENT(TYPE, ALIGNMENT) ALIGNMENT
+#endif
+
+#ifndef STACK_ALIGNMENT_NEEDED
+#define STACK_ALIGNMENT_NEEDED 1
+#endif
+
+
+/* This structure holds data relevant to one variable that will be
+ placed in a stack slot. */
+struct stack_var
+{
+ /* The Variable. */
+ tree decl;
+
+ /* The offset of the variable. During partitioning, this is the
+ offset relative to the partition. After partitioning, this
+ is relative to the stack frame. */
+ HOST_WIDE_INT offset;
+
+ /* Initially, the size of the variable. Later, the size of the partition,
+ if this variable becomes it's partition's representative. */
+ HOST_WIDE_INT size;
+
+ /* The *byte* alignment required for this variable. Or as, with the
+ size, the alignment for this partition. */
+ unsigned int alignb;
+
+ /* The partition representative. */
+ size_t representative;
+
+ /* The next stack variable in the partition, or EOC. */
+ size_t next;
+};
+
+#define EOC ((size_t)-1)
+
+/* We have an array of such objects while deciding allocation. */
+static struct stack_var *stack_vars;
+static size_t stack_vars_alloc;
+static size_t stack_vars_num;
+
+/* An array of indicies such that stack_vars[stack_vars_sorted[i]].size
+ is non-decreasing. */
+static size_t *stack_vars_sorted;
+
+/* We have an interference graph between such objects. This graph
+ is lower triangular. */
+static bool *stack_vars_conflict;
+static size_t stack_vars_conflict_alloc;
+
+/* The phase of the stack frame. This is the known misalignment of
+ virtual_stack_vars_rtx from PREFERRED_STACK_BOUNDARY. That is,
+ (frame_offset+frame_phase) % PREFERRED_STACK_BOUNDARY == 0. */
+static int frame_phase;
+
+/* Used during expand_used_vars to remember if we saw any decls for
+ which we'd like to enable stack smashing protection. */
+static bool has_protected_decls;
+
+/* Used during expand_used_vars. Remember if we say a character buffer
+ smaller than our cutoff threshold. Used for -Wstack-protector. */
+static bool has_short_buffer;
+
+/* Discover the byte alignment to use for DECL. Ignore alignment
+ we can't do with expected alignment of the stack boundary. */
+
+static unsigned int
+get_decl_align_unit (tree decl)
+{
+ unsigned int align;
+
+ align = DECL_ALIGN (decl);
+ align = LOCAL_ALIGNMENT (TREE_TYPE (decl), align);
+ if (align > PREFERRED_STACK_BOUNDARY)
+ align = PREFERRED_STACK_BOUNDARY;
+ if (cfun->stack_alignment_needed < align)
+ cfun->stack_alignment_needed = align;
+
+ return align / BITS_PER_UNIT;
+}
+
+/* Allocate SIZE bytes at byte alignment ALIGN from the stack frame.
+ Return the frame offset. */
+
+static HOST_WIDE_INT
+alloc_stack_frame_space (HOST_WIDE_INT size, HOST_WIDE_INT align)
+{
+ HOST_WIDE_INT offset, new_frame_offset;
+
+ new_frame_offset = frame_offset;
+ if (FRAME_GROWS_DOWNWARD)
+ {
+ new_frame_offset -= size + frame_phase;
+ new_frame_offset &= -align;
+ new_frame_offset += frame_phase;
+ offset = new_frame_offset;
+ }
+ else
+ {
+ new_frame_offset -= frame_phase;
+ new_frame_offset += align - 1;
+ new_frame_offset &= -align;
+ new_frame_offset += frame_phase;
+ offset = new_frame_offset;
+ new_frame_offset += size;
+ }
+ frame_offset = new_frame_offset;
+
+ return offset;
+}
+
+/* Accumulate DECL into STACK_VARS. */
+
+static void
+add_stack_var (tree decl)
+{
+ if (stack_vars_num >= stack_vars_alloc)
+ {
+ if (stack_vars_alloc)
+ stack_vars_alloc = stack_vars_alloc * 3 / 2;
+ else
+ stack_vars_alloc = 32;
+ stack_vars
+ = XRESIZEVEC (struct stack_var, stack_vars, stack_vars_alloc);
+ }
+ stack_vars[stack_vars_num].decl = decl;
+ stack_vars[stack_vars_num].offset = 0;
+ stack_vars[stack_vars_num].size = tree_low_cst (DECL_SIZE_UNIT (decl), 1);
+ stack_vars[stack_vars_num].alignb = get_decl_align_unit (decl);
+
+ /* All variables are initially in their own partition. */
+ stack_vars[stack_vars_num].representative = stack_vars_num;
+ stack_vars[stack_vars_num].next = EOC;
+
+ /* Ensure that this decl doesn't get put onto the list twice. */
+ SET_DECL_RTL (decl, pc_rtx);
+
+ stack_vars_num++;
+}
+
+/* Compute the linear index of a lower-triangular coordinate (I, J). */
+
+static size_t
+triangular_index (size_t i, size_t j)
+{
+ if (i < j)
+ {
+ size_t t;
+ t = i, i = j, j = t;
+ }
+ return (i * (i + 1)) / 2 + j;
+}
+
+/* Ensure that STACK_VARS_CONFLICT is large enough for N objects. */
+
+static void
+resize_stack_vars_conflict (size_t n)
+{
+ size_t size = triangular_index (n-1, n-1) + 1;
+
+ if (size <= stack_vars_conflict_alloc)
+ return;
+
+ stack_vars_conflict = XRESIZEVEC (bool, stack_vars_conflict, size);
+ memset (stack_vars_conflict + stack_vars_conflict_alloc, 0,
+ (size - stack_vars_conflict_alloc) * sizeof (bool));
+ stack_vars_conflict_alloc = size;
+}
+
+/* Make the decls associated with luid's X and Y conflict. */
+
+static void
+add_stack_var_conflict (size_t x, size_t y)
+{
+ size_t index = triangular_index (x, y);
+ gcc_assert (index < stack_vars_conflict_alloc);
+ stack_vars_conflict[index] = true;
+}
+
+/* Check whether the decls associated with luid's X and Y conflict. */
+
+static bool
+stack_var_conflict_p (size_t x, size_t y)
+{
+ size_t index = triangular_index (x, y);
+ gcc_assert (index < stack_vars_conflict_alloc);
+ return stack_vars_conflict[index];
+}
+
+/* Returns true if TYPE is or contains a union type. */
+
+static bool
+aggregate_contains_union_type (tree type)
+{
+ tree field;
+
+ if (TREE_CODE (type) == UNION_TYPE
+ || TREE_CODE (type) == QUAL_UNION_TYPE)
+ return true;
+ if (TREE_CODE (type) == ARRAY_TYPE)
+ return aggregate_contains_union_type (TREE_TYPE (type));
+ if (TREE_CODE (type) != RECORD_TYPE)
+ return false;
+
+ for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
+ if (TREE_CODE (field) == FIELD_DECL)
+ if (aggregate_contains_union_type (TREE_TYPE (field)))
+ return true;
+
+ return false;
+}
+
+/* A subroutine of expand_used_vars. If two variables X and Y have alias
+ sets that do not conflict, then do add a conflict for these variables
+ in the interference graph. We also need to make sure to add conflicts
+ for union containing structures. Else RTL alias analysis comes along
+ and due to type based aliasing rules decides that for two overlapping
+ union temporaries { short s; int i; } accesses to the same mem through
+ different types may not alias and happily reorders stores across
+ life-time boundaries of the temporaries (See PR25654).
+ We also have to mind MEM_IN_STRUCT_P and MEM_SCALAR_P. */
+
+static void
+add_alias_set_conflicts (void)
+{
+ size_t i, j, n = stack_vars_num;
+
+ for (i = 0; i < n; ++i)
+ {
+ tree type_i = TREE_TYPE (stack_vars[i].decl);
+ bool aggr_i = AGGREGATE_TYPE_P (type_i);
+ bool contains_union;
+
+ contains_union = aggregate_contains_union_type (type_i);
+ for (j = 0; j < i; ++j)
+ {
+ tree type_j = TREE_TYPE (stack_vars[j].decl);
+ bool aggr_j = AGGREGATE_TYPE_P (type_j);
+ if (aggr_i != aggr_j
+ /* Either the objects conflict by means of type based
+ aliasing rules, or we need to add a conflict. */
+ || !objects_must_conflict_p (type_i, type_j)
+ /* In case the types do not conflict ensure that access
+ to elements will conflict. In case of unions we have
+ to be careful as type based aliasing rules may say
+ access to the same memory does not conflict. So play
+ safe and add a conflict in this case. */
+ || contains_union)
+ add_stack_var_conflict (i, j);
+ }
+ }
+}
+
+/* A subroutine of partition_stack_vars. A comparison function for qsort,
+ sorting an array of indicies by the size of the object. */
+
+static int
+stack_var_size_cmp (const void *a, const void *b)
+{
+ HOST_WIDE_INT sa = stack_vars[*(const size_t *)a].size;
+ HOST_WIDE_INT sb = stack_vars[*(const size_t *)b].size;
+
+ if (sa < sb)
+ return -1;
+ if (sa > sb)
+ return 1;
+ return 0;
+}
+
+/* A subroutine of partition_stack_vars. The UNION portion of a UNION/FIND
+ partitioning algorithm. Partitions A and B are known to be non-conflicting.
+ Merge them into a single partition A.
+
+ At the same time, add OFFSET to all variables in partition B. At the end
+ of the partitioning process we've have a nice block easy to lay out within
+ the stack frame. */
+
+static void
+union_stack_vars (size_t a, size_t b, HOST_WIDE_INT offset)
+{
+ size_t i, last;
+
+ /* Update each element of partition B with the given offset,
+ and merge them into partition A. */
+ for (last = i = b; i != EOC; last = i, i = stack_vars[i].next)
+ {
+ stack_vars[i].offset += offset;
+ stack_vars[i].representative = a;
+ }
+ stack_vars[last].next = stack_vars[a].next;
+ stack_vars[a].next = b;
+
+ /* Update the required alignment of partition A to account for B. */
+ if (stack_vars[a].alignb < stack_vars[b].alignb)
+ stack_vars[a].alignb = stack_vars[b].alignb;
+
+ /* Update the interference graph and merge the conflicts. */
+ for (last = stack_vars_num, i = 0; i < last; ++i)
+ if (stack_var_conflict_p (b, i))
+ add_stack_var_conflict (a, i);
+}
+/* A subroutine of expand_used_vars. Binpack the variables into
+ partitions constrained by the interference graph. The overall
+ algorithm used is as follows:
+
+ Sort the objects by size.
+ For each object A {
+ S = size(A)
+ O = 0
+ loop {
+ Look for the largest non-conflicting object B with size <= S.
+ UNION (A, B)
+ offset(B) = O
+ O += size(B)
+ S -= size(B)
+ }
+ }
+*/
+
+static void
+partition_stack_vars (void)
+{
+ size_t si, sj, n = stack_vars_num;
+
+ stack_vars_sorted = XNEWVEC (size_t, stack_vars_num);
+ for (si = 0; si < n; ++si)
+ stack_vars_sorted[si] = si;
+
+ if (n == 1)
+ return;
+
+ qsort (stack_vars_sorted, n, sizeof (size_t), stack_var_size_cmp);
+
+ /* Special case: detect when all variables conflict, and thus we can't
+ do anything during the partitioning loop. It isn't uncommon (with
+ C code at least) to declare all variables at the top of the function,
+ and if we're not inlining, then all variables will be in the same scope.
+ Take advantage of very fast libc routines for this scan. */
+ gcc_assert (sizeof(bool) == sizeof(char));
+ if (memchr (stack_vars_conflict, false, stack_vars_conflict_alloc) == NULL)
+ return;
+
+ for (si = 0; si < n; ++si)
+ {
+ size_t i = stack_vars_sorted[si];
+ HOST_WIDE_INT isize = stack_vars[i].size;
+ HOST_WIDE_INT offset = 0;
+
+ for (sj = si; sj-- > 0; )
+ {
+ size_t j = stack_vars_sorted[sj];
+ HOST_WIDE_INT jsize = stack_vars[j].size;
+ unsigned int jalign = stack_vars[j].alignb;
+
+ /* Ignore objects that aren't partition representatives. */
+ if (stack_vars[j].representative != j)
+ continue;
+
+ /* Ignore objects too large for the remaining space. */
+ if (isize < jsize)
+ continue;
+
+ /* Ignore conflicting objects. */
+ if (stack_var_conflict_p (i, j))
+ continue;
+
+ /* Refine the remaining space check to include alignment. */
+ if (offset & (jalign - 1))
+ {
+ HOST_WIDE_INT toff = offset;
+ toff += jalign - 1;
+ toff &= -(HOST_WIDE_INT)jalign;
+ if (isize - (toff - offset) < jsize)
+ continue;
+
+ isize -= toff - offset;
+ offset = toff;
+ }
+
+ /* UNION the objects, placing J at OFFSET. */
+ union_stack_vars (i, j, offset);
+
+ isize -= jsize;
+ if (isize == 0)
+ break;
+ }
+ }
+}
+
+/* A debugging aid for expand_used_vars. Dump the generated partitions. */
+
+static void
+dump_stack_var_partition (void)
+{
+ size_t si, i, j, n = stack_vars_num;
+
+ for (si = 0; si < n; ++si)
+ {
+ i = stack_vars_sorted[si];
+
+ /* Skip variables that aren't partition representatives, for now. */
+ if (stack_vars[i].representative != i)
+ continue;
+
+ fprintf (dump_file, "Partition %lu: size " HOST_WIDE_INT_PRINT_DEC
+ " align %u\n", (unsigned long) i, stack_vars[i].size,
+ stack_vars[i].alignb);
+
+ for (j = i; j != EOC; j = stack_vars[j].next)
+ {
+ fputc ('\t', dump_file);
+ print_generic_expr (dump_file, stack_vars[j].decl, dump_flags);
+ fprintf (dump_file, ", offset " HOST_WIDE_INT_PRINT_DEC "\n",
+ stack_vars[i].offset);
+ }
+ }
+}
+
+/* Assign rtl to DECL at frame offset OFFSET. */
+
+static void
+expand_one_stack_var_at (tree decl, HOST_WIDE_INT offset)
+{
+ HOST_WIDE_INT align;
+ rtx x;
+
+ /* If this fails, we've overflowed the stack frame. Error nicely? */
+ gcc_assert (offset == trunc_int_for_mode (offset, Pmode));
+
+ x = plus_constant (virtual_stack_vars_rtx, offset);
+ x = gen_rtx_MEM (DECL_MODE (decl), x);
+
+ /* Set alignment we actually gave this decl. */
+ offset -= frame_phase;
+ align = offset & -offset;
+ align *= BITS_PER_UNIT;
+ if (align > STACK_BOUNDARY || align == 0)
+ align = STACK_BOUNDARY;
+ DECL_ALIGN (decl) = align;
+ DECL_USER_ALIGN (decl) = 0;
+
+ set_mem_attributes (x, decl, true);
+ SET_DECL_RTL (decl, x);
+}
+
+/* A subroutine of expand_used_vars. Give each partition representative
+ a unique location within the stack frame. Update each partition member
+ with that location. */
+
+static void
+expand_stack_vars (bool (*pred) (tree))
+{
+ size_t si, i, j, n = stack_vars_num;
+
+ for (si = 0; si < n; ++si)
+ {
+ HOST_WIDE_INT offset;
+
+ i = stack_vars_sorted[si];
+
+ /* Skip variables that aren't partition representatives, for now. */
+ if (stack_vars[i].representative != i)
+ continue;
+
+ /* Skip variables that have already had rtl assigned. See also
+ add_stack_var where we perpetrate this pc_rtx hack. */
+ if (DECL_RTL (stack_vars[i].decl) != pc_rtx)
+ continue;
+
+ /* Check the predicate to see whether this variable should be
+ allocated in this pass. */
+ if (pred && !pred (stack_vars[i].decl))
+ continue;
+
+ offset = alloc_stack_frame_space (stack_vars[i].size,
+ stack_vars[i].alignb);
+
+ /* Create rtl for each variable based on their location within the
+ partition. */
+ for (j = i; j != EOC; j = stack_vars[j].next)
+ expand_one_stack_var_at (stack_vars[j].decl,
+ stack_vars[j].offset + offset);
+ }
+}
+
+/* A subroutine of expand_one_var. Called to immediately assign rtl
+ to a variable to be allocated in the stack frame. */
+
+static void
+expand_one_stack_var (tree var)
+{
+ HOST_WIDE_INT size, offset, align;
+
+ size = tree_low_cst (DECL_SIZE_UNIT (var), 1);
+ align = get_decl_align_unit (var);
+ offset = alloc_stack_frame_space (size, align);
+
+ expand_one_stack_var_at (var, offset);
+}
+
+/* A subroutine of expand_one_var. Called to assign rtl
+ to a TREE_STATIC VAR_DECL. */
+
+static void
+expand_one_static_var (tree var)
+{
+ /* In unit-at-a-time all the static variables are expanded at the end
+ of compilation process. */
+ if (flag_unit_at_a_time)
+ return;
+ /* If this is an inlined copy of a static local variable,
+ look up the original. */
+ var = DECL_ORIGIN (var);
+
+ /* If we've already processed this variable because of that, do nothing. */
+ if (TREE_ASM_WRITTEN (var))
+ return;
+
+ /* Give the front end a chance to do whatever. In practice, this is
+ resolving duplicate names for IMA in C. */
+ if (lang_hooks.expand_decl (var))
+ return;
+
+ /* Otherwise, just emit the variable. */
+ rest_of_decl_compilation (var, 0, 0);
+}
+
+/* A subroutine of expand_one_var. Called to assign rtl to a VAR_DECL
+ that will reside in a hard register. */
+
+static void
+expand_one_hard_reg_var (tree var)
+{
+ rest_of_decl_compilation (var, 0, 0);
+}
+
+/* A subroutine of expand_one_var. Called to assign rtl to a VAR_DECL
+ that will reside in a pseudo register. */
+
+static void
+expand_one_register_var (tree var)
+{
+ tree type = TREE_TYPE (var);
+ int unsignedp = TYPE_UNSIGNED (type);
+ enum machine_mode reg_mode
+ = promote_mode (type, DECL_MODE (var), &unsignedp, 0);
+ rtx x = gen_reg_rtx (reg_mode);
+
+ SET_DECL_RTL (var, x);
+
+ /* Note if the object is a user variable. */
+ if (!DECL_ARTIFICIAL (var))
+ {
+ mark_user_reg (x);
+
+ /* Trust user variables which have a pointer type to really
+ be pointers. Do not trust compiler generated temporaries
+ as our type system is totally busted as it relates to
+ pointer arithmetic which translates into lots of compiler
+ generated objects with pointer types, but which are not really
+ pointers. */
+ if (POINTER_TYPE_P (type))
+ mark_reg_pointer (x, TYPE_ALIGN (TREE_TYPE (TREE_TYPE (var))));
+ }
+}
+
+/* A subroutine of expand_one_var. Called to assign rtl to a VAR_DECL that
+ has some associated error, e.g. its type is error-mark. We just need
+ to pick something that won't crash the rest of the compiler. */
+
+static void
+expand_one_error_var (tree var)
+{
+ enum machine_mode mode = DECL_MODE (var);
+ rtx x;
+
+ if (mode == BLKmode)
+ x = gen_rtx_MEM (BLKmode, const0_rtx);
+ else if (mode == VOIDmode)
+ x = const0_rtx;
+ else
+ x = gen_reg_rtx (mode);
+
+ SET_DECL_RTL (var, x);
+}
+
+/* A subroutine of expand_one_var. VAR is a variable that will be
+ allocated to the local stack frame. Return true if we wish to
+ add VAR to STACK_VARS so that it will be coalesced with other
+ variables. Return false to allocate VAR immediately.
+
+ This function is used to reduce the number of variables considered
+ for coalescing, which reduces the size of the quadratic problem. */
+
+static bool
+defer_stack_allocation (tree var, bool toplevel)
+{
+ /* If stack protection is enabled, *all* stack variables must be deferred,
+ so that we can re-order the strings to the top of the frame. */
+ if (flag_stack_protect)
+ return true;
+
+ /* Variables in the outermost scope automatically conflict with
+ every other variable. The only reason to want to defer them
+ at all is that, after sorting, we can more efficiently pack
+ small variables in the stack frame. Continue to defer at -O2. */
+ if (toplevel && optimize < 2)
+ return false;
+
+ /* Without optimization, *most* variables are allocated from the
+ stack, which makes the quadratic problem large exactly when we
+ want compilation to proceed as quickly as possible. On the
+ other hand, we don't want the function's stack frame size to
+ get completely out of hand. So we avoid adding scalars and
+ "small" aggregates to the list at all. */
+ if (optimize == 0 && tree_low_cst (DECL_SIZE_UNIT (var), 1) < 32)
+ return false;
+
+ return true;
+}
+
+/* A subroutine of expand_used_vars. Expand one variable according to
+ its flavor. Variables to be placed on the stack are not actually
+ expanded yet, merely recorded. */
+
+static void
+expand_one_var (tree var, bool toplevel)
+{
+ if (TREE_CODE (var) != VAR_DECL)
+ lang_hooks.expand_decl (var);
+ else if (DECL_EXTERNAL (var))
+ ;
+ else if (DECL_HAS_VALUE_EXPR_P (var))
+ ;
+ else if (TREE_STATIC (var))
+ expand_one_static_var (var);
+ else if (DECL_RTL_SET_P (var))
+ ;
+ else if (TREE_TYPE (var) == error_mark_node)
+ expand_one_error_var (var);
+ else if (DECL_HARD_REGISTER (var))
+ expand_one_hard_reg_var (var);
+ else if (use_register_for_decl (var))
+ expand_one_register_var (var);
+ else if (defer_stack_allocation (var, toplevel))
+ add_stack_var (var);
+ else
+ expand_one_stack_var (var);
+}
+
+/* A subroutine of expand_used_vars. Walk down through the BLOCK tree
+ expanding variables. Those variables that can be put into registers
+ are allocated pseudos; those that can't are put on the stack.
+
+ TOPLEVEL is true if this is the outermost BLOCK. */
+
+static void
+expand_used_vars_for_block (tree block, bool toplevel)
+{
+ size_t i, j, old_sv_num, this_sv_num, new_sv_num;
+ tree t;
+
+ old_sv_num = toplevel ? 0 : stack_vars_num;
+
+ /* Expand all variables at this level. */
+ for (t = BLOCK_VARS (block); t ; t = TREE_CHAIN (t))
+ if (TREE_USED (t))
+ expand_one_var (t, toplevel);
+
+ this_sv_num = stack_vars_num;
+
+ /* Expand all variables at containing levels. */
+ for (t = BLOCK_SUBBLOCKS (block); t ; t = BLOCK_CHAIN (t))
+ expand_used_vars_for_block (t, false);
+
+ /* Since we do not track exact variable lifetimes (which is not even
+ possible for varibles whose address escapes), we mirror the block
+ tree in the interference graph. Here we cause all variables at this
+ level, and all sublevels, to conflict. Do make certain that a
+ variable conflicts with itself. */
+ if (old_sv_num < this_sv_num)
+ {
+ new_sv_num = stack_vars_num;
+ resize_stack_vars_conflict (new_sv_num);
+
+ for (i = old_sv_num; i < new_sv_num; ++i)
+ for (j = i < this_sv_num ? i+1 : this_sv_num; j-- > old_sv_num ;)
+ add_stack_var_conflict (i, j);
+ }
+}
+
+/* A subroutine of expand_used_vars. Walk down through the BLOCK tree
+ and clear TREE_USED on all local variables. */
+
+static void
+clear_tree_used (tree block)
+{
+ tree t;
+
+ for (t = BLOCK_VARS (block); t ; t = TREE_CHAIN (t))
+ /* if (!TREE_STATIC (t) && !DECL_EXTERNAL (t)) */
+ TREE_USED (t) = 0;
+
+ for (t = BLOCK_SUBBLOCKS (block); t ; t = BLOCK_CHAIN (t))
+ clear_tree_used (t);
+}
+
+/* Examine TYPE and determine a bit mask of the following features. */
+
+#define SPCT_HAS_LARGE_CHAR_ARRAY 1
+#define SPCT_HAS_SMALL_CHAR_ARRAY 2
+#define SPCT_HAS_ARRAY 4
+#define SPCT_HAS_AGGREGATE 8
+
+static unsigned int
+stack_protect_classify_type (tree type)
+{
+ unsigned int ret = 0;
+ tree t;
+
+ switch (TREE_CODE (type))
+ {
+ case ARRAY_TYPE:
+ t = TYPE_MAIN_VARIANT (TREE_TYPE (type));
+ if (t == char_type_node
+ || t == signed_char_type_node
+ || t == unsigned_char_type_node)
+ {
+ unsigned HOST_WIDE_INT max = PARAM_VALUE (PARAM_SSP_BUFFER_SIZE);
+ unsigned HOST_WIDE_INT len;
+
+ if (!TYPE_SIZE_UNIT (type)
+ || !host_integerp (TYPE_SIZE_UNIT (type), 1))
+ len = max;
+ else
+ len = tree_low_cst (TYPE_SIZE_UNIT (type), 1);
+
+ if (len < max)
+ ret = SPCT_HAS_SMALL_CHAR_ARRAY | SPCT_HAS_ARRAY;
+ else
+ ret = SPCT_HAS_LARGE_CHAR_ARRAY | SPCT_HAS_ARRAY;
+ }
+ else
+ ret = SPCT_HAS_ARRAY;
+ break;
+
+ case UNION_TYPE:
+ case QUAL_UNION_TYPE:
+ case RECORD_TYPE:
+ ret = SPCT_HAS_AGGREGATE;
+ for (t = TYPE_FIELDS (type); t ; t = TREE_CHAIN (t))
+ if (TREE_CODE (t) == FIELD_DECL)
+ ret |= stack_protect_classify_type (TREE_TYPE (t));
+ break;
+
+ default:
+ break;
+ }
+
+ return ret;
+}
+
+/* Return nonzero if DECL should be segregated into the "vulnerable" upper
+ part of the local stack frame. Remember if we ever return nonzero for
+ any variable in this function. The return value is the phase number in
+ which the variable should be allocated. */
+
+static int
+stack_protect_decl_phase (tree decl)
+{
+ unsigned int bits = stack_protect_classify_type (TREE_TYPE (decl));
+ int ret = 0;
+
+ if (bits & SPCT_HAS_SMALL_CHAR_ARRAY)
+ has_short_buffer = true;
+
+ if (flag_stack_protect == 2)
+ {
+ if ((bits & (SPCT_HAS_SMALL_CHAR_ARRAY | SPCT_HAS_LARGE_CHAR_ARRAY))
+ && !(bits & SPCT_HAS_AGGREGATE))
+ ret = 1;
+ else if (bits & SPCT_HAS_ARRAY)
+ ret = 2;
+ }
+ else
+ ret = (bits & SPCT_HAS_LARGE_CHAR_ARRAY) != 0;
+
+ if (ret)
+ has_protected_decls = true;
+
+ return ret;
+}
+
+/* Two helper routines that check for phase 1 and phase 2. These are used
+ as callbacks for expand_stack_vars. */
+
+static bool
+stack_protect_decl_phase_1 (tree decl)
+{
+ return stack_protect_decl_phase (decl) == 1;
+}
+
+static bool
+stack_protect_decl_phase_2 (tree decl)
+{
+ return stack_protect_decl_phase (decl) == 2;
+}
+
+/* Ensure that variables in different stack protection phases conflict
+ so that they are not merged and share the same stack slot. */
+
+static void
+add_stack_protection_conflicts (void)
+{
+ size_t i, j, n = stack_vars_num;
+ unsigned char *phase;
+
+ phase = XNEWVEC (unsigned char, n);
+ for (i = 0; i < n; ++i)
+ phase[i] = stack_protect_decl_phase (stack_vars[i].decl);
+
+ for (i = 0; i < n; ++i)
+ {
+ unsigned char ph_i = phase[i];
+ for (j = 0; j < i; ++j)
+ if (ph_i != phase[j])
+ add_stack_var_conflict (i, j);
+ }
+
+ XDELETEVEC (phase);
+}
+
+/* Create a decl for the guard at the top of the stack frame. */
+
+static void
+create_stack_guard (void)
+{
+ tree guard = build_decl (VAR_DECL, NULL, ptr_type_node);
+ TREE_THIS_VOLATILE (guard) = 1;
+ TREE_USED (guard) = 1;
+ expand_one_stack_var (guard);
+ cfun->stack_protect_guard = guard;
+}
+
+/* Expand all variables used in the function. */
+
+static void
+expand_used_vars (void)
+{
+ tree t, outer_block = DECL_INITIAL (current_function_decl);
+
+ /* Compute the phase of the stack frame for this function. */
+ {
+ int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
+ int off = STARTING_FRAME_OFFSET % align;
+ frame_phase = off ? align - off : 0;
+ }
+
+ /* Set TREE_USED on all variables in the unexpanded_var_list. */
+ for (t = cfun->unexpanded_var_list; t; t = TREE_CHAIN (t))
+ TREE_USED (TREE_VALUE (t)) = 1;
+
+ /* Clear TREE_USED on all variables associated with a block scope. */
+ clear_tree_used (outer_block);
+
+ /* Initialize local stack smashing state. */
+ has_protected_decls = false;
+ has_short_buffer = false;
+
+ /* At this point all variables on the unexpanded_var_list with TREE_USED
+ set are not associated with any block scope. Lay them out. */
+ for (t = cfun->unexpanded_var_list; t; t = TREE_CHAIN (t))
+ {
+ tree var = TREE_VALUE (t);
+ bool expand_now = false;
+
+ /* We didn't set a block for static or extern because it's hard
+ to tell the difference between a global variable (re)declared
+ in a local scope, and one that's really declared there to
+ begin with. And it doesn't really matter much, since we're
+ not giving them stack space. Expand them now. */
+ if (TREE_STATIC (var) || DECL_EXTERNAL (var))
+ expand_now = true;
+
+ /* Any variable that could have been hoisted into an SSA_NAME
+ will have been propagated anywhere the optimizers chose,
+ i.e. not confined to their original block. Allocate them
+ as if they were defined in the outermost scope. */
+ else if (is_gimple_reg (var))
+ expand_now = true;
+
+ /* If the variable is not associated with any block, then it
+ was created by the optimizers, and could be live anywhere
+ in the function. */
+ else if (TREE_USED (var))
+ expand_now = true;
+
+ /* Finally, mark all variables on the list as used. We'll use
+ this in a moment when we expand those associated with scopes. */
+ TREE_USED (var) = 1;
+
+ if (expand_now)
+ expand_one_var (var, true);
+ }
+ cfun->unexpanded_var_list = NULL_TREE;
+
+ /* At this point, all variables within the block tree with TREE_USED
+ set are actually used by the optimized function. Lay them out. */
+ expand_used_vars_for_block (outer_block, true);
+
+ if (stack_vars_num > 0)
+ {
+ /* Due to the way alias sets work, no variables with non-conflicting
+ alias sets may be assigned the same address. Add conflicts to
+ reflect this. */
+ add_alias_set_conflicts ();
+
+ /* If stack protection is enabled, we don't share space between
+ vulnerable data and non-vulnerable data. */
+ if (flag_stack_protect)
+ add_stack_protection_conflicts ();
+
+ /* Now that we have collected all stack variables, and have computed a
+ minimal interference graph, attempt to save some stack space. */
+ partition_stack_vars ();
+ if (dump_file)
+ dump_stack_var_partition ();
+ }
+
+ /* There are several conditions under which we should create a
+ stack guard: protect-all, alloca used, protected decls present. */
+ if (flag_stack_protect == 2
+ || (flag_stack_protect
+ && (current_function_calls_alloca || has_protected_decls)))
+ create_stack_guard ();
+
+ /* Assign rtl to each variable based on these partitions. */
+ if (stack_vars_num > 0)
+ {
+ /* Reorder decls to be protected by iterating over the variables
+ array multiple times, and allocating out of each phase in turn. */
+ /* ??? We could probably integrate this into the qsort we did
+ earlier, such that we naturally see these variables first,
+ and thus naturally allocate things in the right order. */
+ if (has_protected_decls)
+ {
+ /* Phase 1 contains only character arrays. */
+ expand_stack_vars (stack_protect_decl_phase_1);
+
+ /* Phase 2 contains other kinds of arrays. */
+ if (flag_stack_protect == 2)
+ expand_stack_vars (stack_protect_decl_phase_2);
+ }
+
+ expand_stack_vars (NULL);
+
+ /* Free up stack variable graph data. */
+ XDELETEVEC (stack_vars);
+ XDELETEVEC (stack_vars_sorted);
+ XDELETEVEC (stack_vars_conflict);
+ stack_vars = NULL;
+ stack_vars_alloc = stack_vars_num = 0;
+ stack_vars_conflict = NULL;
+ stack_vars_conflict_alloc = 0;
+ }
+
+ /* If the target requires that FRAME_OFFSET be aligned, do it. */
+ if (STACK_ALIGNMENT_NEEDED)
+ {
+ HOST_WIDE_INT align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
+ if (!FRAME_GROWS_DOWNWARD)
+ frame_offset += align - 1;
+ frame_offset &= -align;
+ }
+}
+
+
+/* If we need to produce a detailed dump, print the tree representation
+ for STMT to the dump file. SINCE is the last RTX after which the RTL
+ generated for STMT should have been appended. */
+
+static void
+maybe_dump_rtl_for_tree_stmt (tree stmt, rtx since)
+{
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "\n;; ");
+ print_generic_expr (dump_file, stmt, TDF_SLIM);
+ fprintf (dump_file, "\n");
+
+ print_rtl (dump_file, since ? NEXT_INSN (since) : since);
+ }
+}
/* A subroutine of expand_gimple_basic_block. Expand one COND_EXPR.
Returns a new basic block if we've terminated the current basic
tree pred = COND_EXPR_COND (stmt);
tree then_exp = COND_EXPR_THEN (stmt);
tree else_exp = COND_EXPR_ELSE (stmt);
- rtx last;
+ rtx last2, last;
+
+ last2 = last = get_last_insn ();
extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
if (EXPR_LOCUS (stmt))
if (TREE_CODE (then_exp) == GOTO_EXPR && IS_EMPTY_STMT (else_exp))
{
jumpif (pred, label_rtx (GOTO_DESTINATION (then_exp)));
+ add_reg_br_prob_note (last, true_edge->probability);
+ maybe_dump_rtl_for_tree_stmt (stmt, last);
+ if (EXPR_LOCUS (then_exp))
+ emit_line_note (*(EXPR_LOCUS (then_exp)));
return NULL;
}
if (TREE_CODE (else_exp) == GOTO_EXPR && IS_EMPTY_STMT (then_exp))
{
jumpifnot (pred, label_rtx (GOTO_DESTINATION (else_exp)));
+ add_reg_br_prob_note (last, false_edge->probability);
+ maybe_dump_rtl_for_tree_stmt (stmt, last);
+ if (EXPR_LOCUS (else_exp))
+ emit_line_note (*(EXPR_LOCUS (else_exp)));
return NULL;
}
- if (TREE_CODE (then_exp) != GOTO_EXPR || TREE_CODE (else_exp) != GOTO_EXPR)
- abort ();
+ gcc_assert (TREE_CODE (then_exp) == GOTO_EXPR
+ && TREE_CODE (else_exp) == GOTO_EXPR);
jumpif (pred, label_rtx (GOTO_DESTINATION (then_exp)));
+ add_reg_br_prob_note (last, true_edge->probability);
last = get_last_insn ();
expand_expr (else_exp, const0_rtx, VOIDmode, 0);
BB_END (new_bb) = PREV_INSN (BB_END (new_bb));
update_bb_for_insn (new_bb);
- if (dump_file)
- {
- dump_bb (bb, dump_file, 0);
- dump_bb (new_bb, dump_file, 0);
- }
+ maybe_dump_rtl_for_tree_stmt (stmt, last2);
+
+ if (EXPR_LOCUS (else_exp))
+ emit_line_note (*(EXPR_LOCUS (else_exp)));
return new_bb;
}
/* A subroutine of expand_gimple_basic_block. Expand one CALL_EXPR
- that has CALL_EXPR_TAILCALL set. Returns a new basic block if we've
- terminated the current basic block and created a new one. */
+ that has CALL_EXPR_TAILCALL set. Returns non-null if we actually
+ generated a tail call (something that might be denied by the ABI
+ rules governing the call; see calls.c).
+
+ Sets CAN_FALLTHRU if we generated a *conditional* tail call, and
+ can still reach the rest of BB. The case here is __builtin_sqrt,
+ where the NaN result goes through the external function (with a
+ tailcall) and the normal result happens via a sqrt instruction. */
static basic_block
-expand_gimple_tailcall (basic_block bb, tree stmt)
+expand_gimple_tailcall (basic_block bb, tree stmt, bool *can_fallthru)
{
- rtx last = get_last_insn ();
+ rtx last2, last;
+ edge e;
+ edge_iterator ei;
+ int probability;
+ gcov_type count;
+
+ last2 = last = get_last_insn ();
expand_expr_stmt (stmt);
for (last = NEXT_INSN (last); last; last = NEXT_INSN (last))
- {
- if (CALL_P (last) && SIBLING_CALL_P (last))
- {
- edge e;
- int probability = 0;
- gcov_type count = 0;
+ if (CALL_P (last) && SIBLING_CALL_P (last))
+ goto found;
- do_pending_stack_adjust ();
- e = bb->succ;
- while (e)
- {
- edge next = e->succ_next;
+ maybe_dump_rtl_for_tree_stmt (stmt, last2);
- if (!(e->flags & (EDGE_ABNORMAL | EDGE_EH)))
- {
- if (e->dest != EXIT_BLOCK_PTR)
- {
- e->dest->count -= e->count;
- e->dest->frequency -= EDGE_FREQUENCY (e);
- if (e->dest->count < 0)
- e->dest->count = 0;
- if (e->dest->frequency < 0)
- e->dest->frequency = 0;
- }
- count += e->count;
- probability += e->probability;
- remove_edge (e);
- }
+ *can_fallthru = true;
+ return NULL;
- e = next;
- }
+ found:
+ /* ??? Wouldn't it be better to just reset any pending stack adjust?
+ Any instructions emitted here are about to be deleted. */
+ do_pending_stack_adjust ();
+
+ /* Remove any non-eh, non-abnormal edges that don't go to exit. */
+ /* ??? I.e. the fallthrough edge. HOWEVER! If there were to be
+ EH or abnormal edges, we shouldn't have created a tail call in
+ the first place. So it seems to me we should just be removing
+ all edges here, or redirecting the existing fallthru edge to
+ the exit block. */
- /* This is somewhat ugly: the call_expr expander often emits
- instructions after the sibcall (to perform the function
- return). These confuse the find_sub_basic_blocks code,
- so we need to get rid of these. */
- last = NEXT_INSN (last);
- if (!BARRIER_P (last))
- abort ();
- while (NEXT_INSN (last))
+ probability = 0;
+ count = 0;
+
+ for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
+ {
+ if (!(e->flags & (EDGE_ABNORMAL | EDGE_EH)))
+ {
+ if (e->dest != EXIT_BLOCK_PTR)
{
- /* For instance an sqrt builtin expander expands if with
- sibcall in the then and label for `else`. */
- if (LABEL_P (NEXT_INSN (last)))
- break;
- delete_insn (NEXT_INSN (last));
+ e->dest->count -= e->count;
+ e->dest->frequency -= EDGE_FREQUENCY (e);
+ if (e->dest->count < 0)
+ e->dest->count = 0;
+ if (e->dest->frequency < 0)
+ e->dest->frequency = 0;
}
- e = make_edge (bb, EXIT_BLOCK_PTR, EDGE_ABNORMAL | EDGE_SIBCALL);
- e->probability += probability;
- e->count += count;
- BB_END (bb) = last;
- update_bb_for_insn (bb);
- if (NEXT_INSN (last))
- bb = create_basic_block (NEXT_INSN (last), get_last_insn (), bb);
- else
- return bb;
+ count += e->count;
+ probability += e->probability;
+ remove_edge (e);
}
+ else
+ ei_next (&ei);
}
- return NULL;
+ /* This is somewhat ugly: the call_expr expander often emits instructions
+ after the sibcall (to perform the function return). These confuse the
+ find_many_sub_basic_blocks code, so we need to get rid of these. */
+ last = NEXT_INSN (last);
+ gcc_assert (BARRIER_P (last));
+
+ *can_fallthru = false;
+ while (NEXT_INSN (last))
+ {
+ /* For instance an sqrt builtin expander expands if with
+ sibcall in the then and label for `else`. */
+ if (LABEL_P (NEXT_INSN (last)))
+ {
+ *can_fallthru = true;
+ break;
+ }
+ delete_insn (NEXT_INSN (last));
+ }
+
+ e = make_edge (bb, EXIT_BLOCK_PTR, EDGE_ABNORMAL | EDGE_SIBCALL);
+ e->probability += probability;
+ e->count += count;
+ BB_END (bb) = last;
+ update_bb_for_insn (bb);
+
+ if (NEXT_INSN (last))
+ {
+ bb = create_basic_block (NEXT_INSN (last), get_last_insn (), bb);
+
+ last = BB_END (bb);
+ if (BARRIER_P (last))
+ BB_END (bb) = PREV_INSN (last);
+ }
+
+ maybe_dump_rtl_for_tree_stmt (stmt, last2);
+
+ return bb;
}
/* Expand basic block BB from GIMPLE trees to RTL. */
static basic_block
-expand_gimple_basic_block (basic_block bb, FILE * dump_file)
+expand_gimple_basic_block (basic_block bb)
{
block_stmt_iterator bsi = bsi_start (bb);
tree stmt = NULL;
rtx note, last;
edge e;
+ edge_iterator ei;
if (dump_file)
{
- tree_register_cfg_hooks ();
- dump_bb (bb, dump_file, 0);
- rtl_register_cfg_hooks ();
+ fprintf (dump_file,
+ "\n;; Generating RTL for tree basic block %d\n",
+ bb->index);
}
+ init_rtl_bb_info (bb);
+ bb->flags |= BB_RTL;
+
if (!bsi_end_p (bsi))
stmt = bsi_stmt (bsi);
BB_HEAD (bb) = NEXT_INSN (BB_HEAD (bb));
bsi_next (&bsi);
note = emit_note_after (NOTE_INSN_BASIC_BLOCK, BB_HEAD (bb));
+
+ maybe_dump_rtl_for_tree_stmt (stmt, last);
}
else
note = BB_HEAD (bb) = emit_note (NOTE_INSN_BASIC_BLOCK);
NOTE_BASIC_BLOCK (note) = bb;
- e = bb->succ;
- while (e)
+ for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
{
- edge next = e->succ_next;
-
/* Clear EDGE_EXECUTABLE. This flag is never used in the backend. */
e->flags &= ~EDGE_EXECUTABLE;
/* At the moment not all abnormal edges match the RTL representation.
- It is safe to remove them here as find_sub_basic_blocks will
+ It is safe to remove them here as find_many_sub_basic_blocks will
rediscover them. In the future we should get this fixed properly. */
if (e->flags & EDGE_ABNORMAL)
remove_edge (e);
-
- e = next;
+ else
+ ei_next (&ei);
}
for (; !bsi_end_p (bsi); bsi_next (&bsi))
{
tree stmt = bsi_stmt (bsi);
- basic_block new_bb = NULL;
+ basic_block new_bb;
if (!stmt)
continue;
/* Expand this statement, then evaluate the resulting RTL and
fixup the CFG accordingly. */
if (TREE_CODE (stmt) == COND_EXPR)
- new_bb = expand_gimple_cond_expr (bb, stmt);
+ {
+ new_bb = expand_gimple_cond_expr (bb, stmt);
+ if (new_bb)
+ return new_bb;
+ }
else
{
tree call = get_call_expr_in (stmt);
if (call && CALL_EXPR_TAILCALL (call))
- new_bb = expand_gimple_tailcall (bb, stmt);
+ {
+ bool can_fallthru;
+ new_bb = expand_gimple_tailcall (bb, stmt, &can_fallthru);
+ if (new_bb)
+ {
+ if (can_fallthru)
+ bb = new_bb;
+ else
+ return new_bb;
+ }
+ }
else
- expand_expr_stmt (stmt);
+ {
+ last = get_last_insn ();
+ expand_expr_stmt (stmt);
+ maybe_dump_rtl_for_tree_stmt (stmt, last);
+ }
}
-
- if (new_bb)
- return new_bb;
}
do_pending_stack_adjust ();
- /* Find the the block tail. The last insn is the block is the insn
+ /* Find the block tail. The last insn in the block is the insn
before a barrier and/or table jump insn. */
last = get_last_insn ();
if (BARRIER_P (last))
last = PREV_INSN (PREV_INSN (last));
BB_END (bb) = last;
- if (dump_file)
- dump_bb (bb, dump_file, 0);
update_bb_for_insn (bb);
return bb;
construct_init_block (void)
{
basic_block init_block, first_block;
- edge e;
+ edge e = NULL;
+ int flags;
- for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
- if (e->dest == ENTRY_BLOCK_PTR->next_bb)
- break;
+ /* Multiple entry points not supported yet. */
+ gcc_assert (EDGE_COUNT (ENTRY_BLOCK_PTR->succs) == 1);
+ init_rtl_bb_info (ENTRY_BLOCK_PTR);
+ init_rtl_bb_info (EXIT_BLOCK_PTR);
+ ENTRY_BLOCK_PTR->flags |= BB_RTL;
+ EXIT_BLOCK_PTR->flags |= BB_RTL;
+
+ e = EDGE_SUCC (ENTRY_BLOCK_PTR, 0);
+
+ /* When entry edge points to first basic block, we don't need jump,
+ otherwise we have to jump into proper target. */
+ if (e && e->dest != ENTRY_BLOCK_PTR->next_bb)
+ {
+ tree label = tree_block_label (e->dest);
+
+ emit_jump (label_rtx (label));
+ flags = 0;
+ }
+ else
+ flags = EDGE_FALLTHRU;
init_block = create_basic_block (NEXT_INSN (get_insns ()),
get_last_insn (),
{
first_block = e->dest;
redirect_edge_succ (e, init_block);
- e = make_edge (init_block, first_block, EDGE_FALLTHRU);
+ e = make_edge (init_block, first_block, flags);
}
else
e = make_edge (init_block, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
rtx head = get_last_insn ();
rtx end;
basic_block exit_block;
- edge e, e2, next;
+ edge e, e2;
+ unsigned ix;
+ edge_iterator ei;
/* Make sure the locus is set to the end of the function, so that
epilogue line numbers and warnings are set properly. */
EXIT_BLOCK_PTR->prev_bb);
exit_block->frequency = EXIT_BLOCK_PTR->frequency;
exit_block->count = EXIT_BLOCK_PTR->count;
- for (e = EXIT_BLOCK_PTR->pred; e; e = next)
+
+ ix = 0;
+ while (ix < EDGE_COUNT (EXIT_BLOCK_PTR->preds))
{
- next = e->pred_next;
+ e = EDGE_PRED (EXIT_BLOCK_PTR, ix);
if (!(e->flags & EDGE_ABNORMAL))
- redirect_edge_succ (e, exit_block);
+ redirect_edge_succ (e, exit_block);
+ else
+ ix++;
}
+
e = make_edge (exit_block, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
e->probability = REG_BR_PROB_BASE;
e->count = EXIT_BLOCK_PTR->count;
- for (e2 = EXIT_BLOCK_PTR->pred; e2; e2 = e2->pred_next)
+ FOR_EACH_EDGE (e2, ei, EXIT_BLOCK_PTR->preds)
if (e2 != e)
{
e->count -= e2->count;
update_bb_for_insn (exit_block);
}
+/* Helper function for discover_nonconstant_array_refs.
+ Look for ARRAY_REF nodes with non-constant indexes and mark them
+ addressable. */
+
+static tree
+discover_nonconstant_array_refs_r (tree * tp, int *walk_subtrees,
+ void *data ATTRIBUTE_UNUSED)
+{
+ tree t = *tp;
+
+ if (IS_TYPE_OR_DECL_P (t))
+ *walk_subtrees = 0;
+ else if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
+ {
+ while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
+ && is_gimple_min_invariant (TREE_OPERAND (t, 1))
+ && (!TREE_OPERAND (t, 2)
+ || is_gimple_min_invariant (TREE_OPERAND (t, 2))))
+ || (TREE_CODE (t) == COMPONENT_REF
+ && (!TREE_OPERAND (t,2)
+ || is_gimple_min_invariant (TREE_OPERAND (t, 2))))
+ || TREE_CODE (t) == BIT_FIELD_REF
+ || TREE_CODE (t) == REALPART_EXPR
+ || TREE_CODE (t) == IMAGPART_EXPR
+ || TREE_CODE (t) == VIEW_CONVERT_EXPR
+ || TREE_CODE (t) == NOP_EXPR
+ || TREE_CODE (t) == CONVERT_EXPR)
+ t = TREE_OPERAND (t, 0);
+
+ if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
+ {
+ t = get_base_address (t);
+ if (t && DECL_P (t))
+ TREE_ADDRESSABLE (t) = 1;
+ }
+
+ *walk_subtrees = 0;
+ }
+
+ return NULL_TREE;
+}
+
+/* RTL expansion is not able to compile array references with variable
+ offsets for arrays stored in single register. Discover such
+ expressions and mark variables as addressable to avoid this
+ scenario. */
+
+static void
+discover_nonconstant_array_refs (void)
+{
+ basic_block bb;
+ block_stmt_iterator bsi;
+
+ FOR_EACH_BB (bb)
+ {
+ for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ walk_tree (bsi_stmt_ptr (bsi), discover_nonconstant_array_refs_r,
+ NULL , NULL);
+ }
+}
+
/* Translate the intermediate representation contained in the CFG
from GIMPLE trees to RTL.
basic_block bb, init_block;
sbitmap blocks;
- if (dump_file)
- {
- fprintf (dump_file, "\n;; Function %s",
- (*lang_hooks.decl_printable_name) (current_function_decl, 2));
- fprintf (dump_file, " (%s)\n",
- IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (current_function_decl)));
- }
+ /* Some backends want to know that we are expanding to RTL. */
+ currently_expanding_to_rtl = 1;
/* Prepare the rtl middle end to start recording block changes. */
reset_block_changes ();
- /* Expand the variables recorded during gimple lowering. This must
- occur before the call to expand_function_start to ensure that
- all used variables are expanded before we expand anything on the
- PENDING_SIZES list. */
+ /* Mark arrays indexed with non-constant indices with TREE_ADDRESSABLE. */
+ discover_nonconstant_array_refs ();
+
+ /* Expand the variables recorded during gimple lowering. */
expand_used_vars ();
+ /* Honor stack protection warnings. */
+ if (warn_stack_protect)
+ {
+ if (current_function_calls_alloca)
+ warning (0, "not protecting local variables: variable length buffer");
+ if (has_short_buffer && !cfun->stack_protect_guard)
+ warning (0, "not protecting function: no buffer at least %d bytes long",
+ (int) PARAM_VALUE (PARAM_SSP_BUFFER_SIZE));
+ }
+
/* Set up parameters and prepare for return, for the function. */
expand_function_start (current_function_decl);
&& DECL_FILE_SCOPE_P (current_function_decl))
expand_main_function ();
- /* Write the flowgraph to a dot file. */
+ /* Initialize the stack_protect_guard field. This must happen after the
+ call to __main (if any) so that the external decl is initialized. */
+ if (cfun->stack_protect_guard)
+ stack_protect_prologue ();
+
+ /* Register rtl specific functions for cfg. */
rtl_register_cfg_hooks ();
init_block = construct_init_block ();
FOR_BB_BETWEEN (bb, init_block->next_bb, EXIT_BLOCK_PTR, next_bb)
- bb = expand_gimple_basic_block (bb, dump_file);
+ bb = expand_gimple_basic_block (bb);
construct_exit_block ();
- /* Convert from NOTE_INSN_EH_REGION style notes, and do other
- sorts of eh initialization. Delay this until after the
- initial rtl dump so that we can see the original nesting. */
+ /* We're done expanding trees to RTL. */
+ currently_expanding_to_rtl = 0;
+
+ /* Convert tree EH labels to RTL EH labels, and clean out any unreachable
+ EH regions. */
convert_from_eh_region_ranges ();
rebuild_jump_labels (get_insns ());
blocks = sbitmap_alloc (last_basic_block);
sbitmap_ones (blocks);
find_many_sub_basic_blocks (blocks);
- purge_all_dead_edges (0);
+ purge_all_dead_edges ();
sbitmap_free (blocks);
compact_blocks ();
#ifdef ENABLE_CHECKING
verify_flow_info();
#endif
+
+ /* There's no need to defer outputting this function any more; we
+ know we want to output it. */
+ DECL_DEFER_OUTPUT (current_function_decl) = 0;
+
+ /* Now that we're done expanding trees to RTL, we shouldn't have any
+ more CONCATs anywhere. */
+ generating_concat_p = 0;
+
+ finalize_block_changes ();
+
+ if (dump_file)
+ {
+ fprintf (dump_file,
+ "\n\n;;\n;; Full RTL generated for this function:\n;;\n");
+ /* And the pass manager will dump RTL for us. */
+ }
+
+ /* If we're emitting a nested function, make sure its parent gets
+ emitted as well. Doing otherwise confuses debug info. */
+ {
+ tree parent;
+ for (parent = DECL_CONTEXT (current_function_decl);
+ parent != NULL_TREE;
+ parent = get_containing_scope (parent))
+ if (TREE_CODE (parent) == FUNCTION_DECL)
+ TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (parent)) = 1;
+ }
+
+ /* We are now committed to emitting code for this function. Do any
+ preparation, such as emitting abstract debug info for the inline
+ before it gets mangled by optimization. */
+ if (cgraph_function_possibly_inlined_p (current_function_decl))
+ (*debug_hooks->outlining_inline_function) (current_function_decl);
+
+ TREE_ASM_WRITTEN (current_function_decl) = 1;
+
+ /* After expanding, the return labels are no longer needed. */
+ return_label = NULL;
+ naked_return_label = NULL;
}
struct tree_opt_pass pass_expand =
/* ??? If TER is enabled, we actually receive GENERIC. */
PROP_gimple_leh | PROP_cfg, /* properties_required */
PROP_rtl, /* properties_provided */
- PROP_gimple_leh, /* properties_destroyed */
+ PROP_trees, /* properties_destroyed */
0, /* todo_flags_start */
- 0 /* todo_flags_finish */
+ TODO_dump_func, /* todo_flags_finish */
+ 'r' /* letter */
};
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