/* 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 "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.
if (profile_status == PROFILE_ABSENT)
return;
for (last = NEXT_INSN (last); last && NEXT_INSN (last); last = NEXT_INSN (last))
- if (GET_CODE (last) == JUMP_INSN)
+ 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)
- || GET_CODE (NEXT_INSN (last)) != JUMP_INSN
+ || !JUMP_P (NEXT_INSN (last))
|| !simplejump_p (NEXT_INSN (last))
- || GET_CODE (NEXT_INSN (NEXT_INSN (last))) != BARRIER
- || GET_CODE (NEXT_INSN (NEXT_INSN (NEXT_INSN (last)))) != CODE_LABEL
+ || !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;
- if (find_reg_note (last, REG_BR_PROB, 0))
- abort ();
+ 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 || GET_CODE (last) != JUMP_INSN || !any_condjump_p (last))
- goto failed;
- if (find_reg_note (last, REG_BR_PROB, 0))
- abort ();
+ 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));
#define STACK_ALIGNMENT_NEEDED 1
#endif
-#ifdef FRAME_GROWS_DOWNWARD
-# undef FRAME_GROWS_DOWNWARD
-# define FRAME_GROWS_DOWNWARD 1
-#else
-# define FRAME_GROWS_DOWNWARD 0
-#endif
-
/* This structure holds data relevant to one variable that will be
placed in a stack slot. */
(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. */
with that location. */
static void
-expand_stack_vars (void)
+expand_stack_vars (bool (*pred) (tree))
{
size_t si, i, j, n = stack_vars_num;
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);
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);
}
/* A subroutine of expand_one_var. Called to assign rtl to a VAR_DECL that
- has some associated error, e.g. it's type is error-mark. We just need
+ 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
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
lang_hooks.expand_decl (var);
else if (DECL_EXTERNAL (var))
;
- else if (DECL_VALUE_EXPR (var))
+ else if (DECL_HAS_VALUE_EXPR_P (var))
;
else if (TREE_STATIC (var))
expand_one_static_var (var);
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 non-zero if DECL should be segregated into the "vulnerable" upper
+ part of the local stack frame. Remember if we ever return non-zero 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
/* 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))
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);
+ }
- /* Assign rtl to each variable based on these partitions. */
- expand_stack_vars ();
+ expand_stack_vars (NULL);
/* Free up stack variable graph data. */
XDELETEVEC (stack_vars);
jumpif (pred, label_rtx (GOTO_DESTINATION (then_exp)));
add_reg_br_prob_note (dump_file, 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 (dump_file, 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;
}
gcc_assert (TREE_CODE (then_exp) == GOTO_EXPR
update_bb_for_insn (new_bb);
maybe_dump_rtl_for_tree_stmt (stmt, last2);
+
+ if (EXPR_LOCUS (else_exp))
+ emit_line_note (*(EXPR_LOCUS (else_exp)));
return new_bb;
}
if (CALL_P (last) && SIBLING_CALL_P (last))
goto found;
- maybe_dump_rtl_for_tree_stmt (stmt, last);
+ maybe_dump_rtl_for_tree_stmt (stmt, last2);
*can_fallthru = true;
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_sub_basic_blocks code, so we need to get rid of these. */
+ find_many_sub_basic_blocks code, so we need to get rid of these. */
last = NEXT_INSN (last);
gcc_assert (BARRIER_P (last));
bb->index);
}
+ init_rtl_bb_info (bb);
+ bb->flags |= BB_RTL;
+
if (!bsi_end_p (bsi))
stmt = bsi_stmt (bsi);
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);
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))
construct_init_block (void)
{
basic_block init_block, first_block;
- edge e = NULL, e2;
- edge_iterator ei;
+ edge e = NULL;
+ int flags;
- FOR_EACH_EDGE (e2, ei, ENTRY_BLOCK_PTR->succs)
- {
- /* Clear EDGE_EXECUTABLE. This flag is never used in the backend.
+ /* 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);
- For all other blocks this edge flag is cleared while expanding
- a basic block in expand_gimple_basic_block, but there we never
- looked at the successors of the entry block.
- This caused PR17513. */
- e2->flags &= ~EDGE_EXECUTABLE;
+ /* 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);
- if (e2->dest == ENTRY_BLOCK_PTR->next_bb)
- e = e2;
+ 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);
ix = 0;
while (ix < EDGE_COUNT (EXIT_BLOCK_PTR->preds))
{
- e = EDGE_I (EXIT_BLOCK_PTR->preds, ix);
+ e = EDGE_PRED (EXIT_BLOCK_PTR, ix);
if (!(e->flags & EDGE_ABNORMAL))
redirect_edge_succ (e, exit_block);
else
/* 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 ();
+ /* 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 ();
/* We're done expanding trees to RTL. */
currently_expanding_to_rtl = 0;
- /* Convert from NOTE_INSN_EH_REGION style notes, and do other
- sorts of eh initialization. */
+ /* 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 ();
"\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;
}
struct tree_opt_pass pass_expand =
PROP_rtl, /* properties_provided */
PROP_gimple_leh, /* properties_destroyed */
0, /* todo_flags_start */
- 0, /* todo_flags_finish */
+ TODO_dump_func, /* todo_flags_finish */
'r' /* letter */
};