/* Rewrite a program in Normal form into SSA.
- Copyright (C) 2001-2015 Free Software Foundation, Inc.
+ Copyright (C) 2001-2020 Free Software Foundation, Inc.
Contributed by Diego Novillo <dnovillo@redhat.com>
This file is part of GCC.
#include "tree.h"
#include "gimple.h"
#include "tree-pass.h"
-#include "tm_p.h"
#include "ssa.h"
-#include "expmed.h"
-#include "insn-config.h"
-#include "emit-rtl.h"
#include "gimple-pretty-print.h"
#include "diagnostic-core.h"
-#include "alias.h"
-#include "fold-const.h"
-#include "flags.h"
#include "langhooks.h"
#include "cfganal.h"
-#include "internal-fn.h"
#include "gimple-iterator.h"
#include "tree-cfg.h"
#include "tree-into-ssa.h"
-#include "dojump.h"
-#include "explow.h"
-#include "calls.h"
-#include "varasm.h"
-#include "stmt.h"
-#include "expr.h"
#include "tree-dfa.h"
#include "tree-ssa.h"
-#include "tree-inline.h"
-#include "cfgloop.h"
#include "domwalk.h"
-#include "params.h"
+#include "statistics.h"
+#include "stringpool.h"
+#include "attribs.h"
+#include "asan.h"
#define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y))
/* Set of SSA names that have been marked to be released after they
were registered in the replacement table. They will be finally
released after we finish updating the SSA web. */
-static bitmap names_to_release;
+bitmap names_to_release;
/* vec of vec of PHIs to rewrite in a basic block. Element I corresponds
the to basic block with index I. Allocated once per compilation, *not*
/* Re-allocate the vector at most once per update/into-SSA. */
if (ver >= len)
- info_for_ssa_name.safe_grow_cleared (num_ssa_names);
+ info_for_ssa_name.safe_grow_cleared (num_ssa_names, true);
/* But allocate infos lazily. */
info = info_for_ssa_name[ver];
FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES)
{
tree sym = USE_FROM_PTR (use_p);
+ if (TREE_CODE (sym) == SSA_NAME)
+ continue;
gcc_checking_assert (DECL_P (sym));
if (!bitmap_bit_p (kills, DECL_UID (sym)))
set_livein_block (sym, bb);
each def to the set of killed symbols. */
FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS)
{
+ if (TREE_CODE (def) == SSA_NAME)
+ continue;
gcc_checking_assert (DECL_P (def));
set_def_block (def, bb, false);
bitmap_set_bit (kills, DECL_UID (def));
if (!blocks_with_phis_to_rewrite)
return;
- bitmap_set_bit (blocks_with_phis_to_rewrite, idx);
-
- n = (unsigned) last_basic_block_for_fn (cfun) + 1;
- if (phis_to_rewrite.length () < n)
- phis_to_rewrite.safe_grow_cleared (n);
+ if (bitmap_set_bit (blocks_with_phis_to_rewrite, idx))
+ {
+ n = (unsigned) last_basic_block_for_fn (cfun) + 1;
+ if (phis_to_rewrite.length () < n)
+ phis_to_rewrite.safe_grow_cleared (n, true);
- phis = phis_to_rewrite[idx];
- phis.reserve (10);
+ phis = phis_to_rewrite[idx];
+ gcc_assert (!phis.exists ());
+ phis.create (10);
+ }
+ else
+ phis = phis_to_rewrite[idx];
phis.safe_push (phi);
phis_to_rewrite[idx] = phis;
timevar_push (TV_TREE_INSERT_PHI_NODES);
+ /* When the gimplifier introduces SSA names it cannot easily avoid
+ situations where abnormal edges added by CFG construction break
+ the use-def dominance requirement. For this case rewrite SSA
+ names with broken use-def dominance out-of-SSA and register them
+ for PHI insertion. We only need to do this if abnormal edges
+ can appear in the function. */
+ tree name;
+ if (cfun->calls_setjmp
+ || cfun->has_nonlocal_label)
+ FOR_EACH_SSA_NAME (i, name, cfun)
+ {
+ gimple *def_stmt = SSA_NAME_DEF_STMT (name);
+ if (SSA_NAME_IS_DEFAULT_DEF (name))
+ continue;
+
+ basic_block def_bb = gimple_bb (def_stmt);
+ imm_use_iterator it;
+ gimple *use_stmt;
+ bool need_phis = false;
+ FOR_EACH_IMM_USE_STMT (use_stmt, it, name)
+ {
+ basic_block use_bb = gimple_bb (use_stmt);
+ if (use_bb != def_bb
+ && ! dominated_by_p (CDI_DOMINATORS, use_bb, def_bb))
+ need_phis = true;
+ }
+ if (need_phis)
+ {
+ tree var = create_tmp_reg (TREE_TYPE (name));
+ use_operand_p use_p;
+ FOR_EACH_IMM_USE_STMT (use_stmt, it, name)
+ {
+ basic_block use_bb = gimple_bb (use_stmt);
+ FOR_EACH_IMM_USE_ON_STMT (use_p, it)
+ SET_USE (use_p, var);
+ update_stmt (use_stmt);
+ set_livein_block (var, use_bb);
+ set_rewrite_uses (use_stmt, true);
+ bitmap_set_bit (interesting_blocks, use_bb->index);
+ }
+ def_operand_p def_p;
+ ssa_op_iter dit;
+ FOR_EACH_SSA_DEF_OPERAND (def_p, def_stmt, dit, SSA_OP_DEF)
+ if (DEF_FROM_PTR (def_p) == name)
+ SET_DEF (def_p, var);
+ update_stmt (def_stmt);
+ set_def_block (var, def_bb, false);
+ set_register_defs (def_stmt, true);
+ bitmap_set_bit (interesting_blocks, def_bb->index);
+ release_ssa_name (name);
+ }
+ }
+
auto_vec<var_info *> vars (var_infos->elements ());
FOR_EACH_HASH_TABLE_ELEMENT (*var_infos, info, var_info_p, hi)
if (info->info.need_phi_state != NEED_PHI_STATE_NO)
if (currdef == NULL_TREE)
{
tree sym = DECL_P (var) ? var : SSA_NAME_VAR (var);
+ if (! sym)
+ sym = create_tmp_reg (TREE_TYPE (var));
currdef = get_or_create_ssa_default_def (cfun, sym);
}
def_temp = gimple_build_debug_source_bind (def, var, NULL);
DECL_ARTIFICIAL (def) = 1;
TREE_TYPE (def) = TREE_TYPE (var);
- DECL_MODE (def) = DECL_MODE (var);
+ SET_DECL_MODE (def, DECL_MODE (var));
gsi =
gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)));
gsi_insert_before (&gsi, def_temp, GSI_SAME_STMT);
FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES)
{
tree var = USE_FROM_PTR (use_p);
+ if (TREE_CODE (var) == SSA_NAME)
+ continue;
gcc_checking_assert (DECL_P (var));
SET_USE (use_p, get_reaching_def (var));
}
tree name;
tree tracked_var;
+ if (TREE_CODE (var) == SSA_NAME)
+ continue;
gcc_checking_assert (DECL_P (var));
if (gimple_clobber_p (stmt)
{
/* If we rewrite a DECL into SSA form then drop its
clobber stmts and replace uses with a new default def. */
- gcc_checking_assert (TREE_CODE (var) == VAR_DECL
- && !gimple_vdef (stmt));
+ gcc_checking_assert (VAR_P (var) && !gimple_vdef (stmt));
gsi_replace (si, gimple_build_nop (), true);
register_new_def (get_or_create_ssa_default_def (cfun, var), var);
break;
class rewrite_dom_walker : public dom_walker
{
public:
- rewrite_dom_walker (cdi_direction direction) : dom_walker (direction) {}
+ rewrite_dom_walker (cdi_direction direction)
+ : dom_walker (direction, ALL_BLOCKS, NULL) {}
- virtual void before_dom_children (basic_block);
+ virtual edge before_dom_children (basic_block);
virtual void after_dom_children (basic_block);
};
(BLOCK_DEFS). Register new definitions for every PHI node in the
block. */
-void
+edge
rewrite_dom_walker::before_dom_children (basic_block bb)
{
if (dump_file && (dump_flags & TDF_DETAILS))
reaching definition for the variable and the edge through which that
definition is reaching the PHI node. */
rewrite_add_phi_arguments (bb);
+
+ return NULL;
}
}
fprintf (file, " Previous CURRDEF (");
- print_generic_expr (file, var, 0);
+ print_generic_expr (file, var);
fprintf (file, ") = ");
if (name)
- print_generic_expr (file, name, 0);
+ print_generic_expr (file, name);
else
fprintf (file, "<NIL>");
fprintf (file, "\n");
{
common_info *info = get_common_info (var);
fprintf (file, "CURRDEF (");
- print_generic_expr (file, var, 0);
+ print_generic_expr (file, var);
fprintf (file, ") = ");
if (info->current_def)
- print_generic_expr (file, info->current_def, 0);
+ print_generic_expr (file, info->current_def);
else
fprintf (file, "<NIL>");
fprintf (file, "\n");
}
+/* If DEF has x_5 = ASAN_POISON () as its current def, add
+ ASAN_POISON_USE (x_5) stmt before GSI to denote the stmt writes into
+ a poisoned (out of scope) variable. */
+
+static void
+maybe_add_asan_poison_write (tree def, gimple_stmt_iterator *gsi)
+{
+ tree cdef = get_current_def (def);
+ if (cdef != NULL
+ && TREE_CODE (cdef) == SSA_NAME
+ && gimple_call_internal_p (SSA_NAME_DEF_STMT (cdef), IFN_ASAN_POISON))
+ {
+ gcall *call
+ = gimple_build_call_internal (IFN_ASAN_POISON_USE, 1, cdef);
+ gimple_set_location (call, gimple_location (gsi_stmt (*gsi)));
+ gsi_insert_before (gsi, call, GSI_SAME_STMT);
+ }
+}
+
+
/* If the operand pointed to by DEF_P is an SSA name in NEW_SSA_NAMES
or OLD_SSA_NAMES, or if it is a symbol marked for renaming,
register it as the current definition for the names replaced by
{
if (gimple_clobber_p (stmt) && is_gimple_reg (sym))
{
- gcc_checking_assert (TREE_CODE (sym) == VAR_DECL);
+ gcc_checking_assert (VAR_P (sym));
/* Replace clobber stmts with a default def. This new use of a
default definition may make it look like SSA_NAMEs have
conflicting lifetimes, so we need special code to let them
def = get_or_create_ssa_default_def (cfun, sym);
}
else
- def = make_ssa_name (def, stmt);
+ {
+ if (asan_sanitize_use_after_scope ())
+ maybe_add_asan_poison_write (def, &gsi);
+ def = make_ssa_name (def, stmt);
+ }
SET_DEF (def_p, def);
tree tracked_var = target_for_debug_bind (sym);
/* Update the argument if there is a reaching def. */
if (reaching_def)
{
- source_location locus;
+ location_t locus;
int arg_i = PHI_ARG_INDEX_FROM_USE (arg_p);
SET_USE (arg_p, reaching_def);
class rewrite_update_dom_walker : public dom_walker
{
public:
- rewrite_update_dom_walker (cdi_direction direction) : dom_walker (direction) {}
+ rewrite_update_dom_walker (cdi_direction direction)
+ : dom_walker (direction, ALL_BLOCKS, NULL) {}
- virtual void before_dom_children (basic_block);
+ virtual edge before_dom_children (basic_block);
virtual void after_dom_children (basic_block);
};
for new SSA names produced in this block (BLOCK_DEFS). Register
new definitions for every PHI node in the block. */
-void
+edge
rewrite_update_dom_walker::before_dom_children (basic_block bb)
{
bool is_abnormal_phi;
block_defs_stack.safe_push (NULL_TREE);
if (!bitmap_bit_p (blocks_to_update, bb->index))
- return;
+ return NULL;
/* Mark the LHS if any of the arguments flows through an abnormal
edge. */
/* Step 3. Update PHI nodes. */
rewrite_update_phi_arguments (bb);
+
+ return NULL;
}
/* Called after visiting block BB. Unwind BLOCK_DEFS_STACK to restore
mark_def_dom_walker (cdi_direction direction);
~mark_def_dom_walker ();
- virtual void before_dom_children (basic_block);
+ virtual edge before_dom_children (basic_block);
private:
/* Notice that this bitmap is indexed using variable UIDs, so it must be
};
mark_def_dom_walker::mark_def_dom_walker (cdi_direction direction)
- : dom_walker (direction), m_kills (BITMAP_ALLOC (NULL))
+ : dom_walker (direction, ALL_BLOCKS, NULL), m_kills (BITMAP_ALLOC (NULL))
{
}
/* Block processing routine for mark_def_sites. Clear the KILLS bitmap
at the start of each block, and call mark_def_sites for each statement. */
-void
+edge
mark_def_dom_walker::before_dom_children (basic_block bb)
{
gimple_stmt_iterator gsi;
bitmap_clear (m_kills);
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
mark_def_sites (bb, gsi_stmt (gsi), m_kills);
+ return NULL;
}
/* Initialize internal data needed during renaming. */
{
bitmap_head *dfs;
basic_block bb;
- unsigned i;
+
+ /* Increase the set of variables we can rewrite into SSA form
+ by clearing TREE_ADDRESSABLE and transform the IL to support this. */
+ if (optimize)
+ execute_update_addresses_taken ();
/* Initialize operand data structures. */
init_ssa_operands (fun);
/* Try to get rid of all gimplifier generated temporaries by making
its SSA names anonymous. This way we can garbage collect them
all after removing unused locals which we do in our TODO. */
- for (i = 1; i < num_ssa_names; ++i)
+ unsigned i;
+ tree name;
+
+ FOR_EACH_SSA_NAME (i, name, cfun)
{
- tree decl, name = ssa_name (i);
- if (!name
- || SSA_NAME_IS_DEFAULT_DEF (name))
+ if (SSA_NAME_IS_DEFAULT_DEF (name))
continue;
- decl = SSA_NAME_VAR (name);
+ tree decl = SSA_NAME_VAR (name);
if (decl
- && TREE_CODE (decl) == VAR_DECL
+ && VAR_P (decl)
&& !VAR_DECL_IS_VIRTUAL_OPERAND (decl)
&& DECL_IGNORED_P (decl))
SET_SSA_NAME_VAR_OR_IDENTIFIER (name, DECL_NAME (decl));
}
+ /* Initialize SSA_NAME_POINTS_TO_READONLY_MEMORY. */
+ tree fnspec = lookup_attribute ("fn spec",
+ TYPE_ATTRIBUTES (TREE_TYPE (fun->decl)));
+ if (fnspec)
+ {
+ fnspec = TREE_VALUE (TREE_VALUE (fnspec));
+ unsigned i = 1;
+ for (tree arg = DECL_ARGUMENTS (cfun->decl);
+ arg; arg = DECL_CHAIN (arg), ++i)
+ {
+ if (i >= (unsigned) TREE_STRING_LENGTH (fnspec))
+ break;
+ if (TREE_STRING_POINTER (fnspec)[i] == 'R'
+ || TREE_STRING_POINTER (fnspec)[i] == 'r')
+ {
+ tree name = ssa_default_def (fun, arg);
+ if (name)
+ SSA_NAME_POINTS_TO_READONLY_MEMORY (name) = 1;
+ }
+ }
+ }
+
return 0;
}
}
}
-
-/* Do a dominator walk starting at BB processing statements that
- reference symbols in SSA operands. This is very similar to
- mark_def_sites, but the scan handles statements whose operands may
- already be SSA names.
+/* Processing statements in BB that reference symbols in SSA operands.
+ This is very similar to mark_def_sites, but the scan handles
+ statements whose operands may already be SSA names.
If INSERT_PHI_P is true, mark those uses as live in the
corresponding block. This is later used by the PHI placement
that. */
static void
-prepare_block_for_update (basic_block bb, bool insert_phi_p)
+prepare_block_for_update_1 (basic_block bb, bool insert_phi_p)
{
- basic_block son;
edge e;
edge_iterator ei;
}
}
- /* Now visit all the blocks dominated by BB. */
- for (son = first_dom_son (CDI_DOMINATORS, bb);
- son;
- son = next_dom_son (CDI_DOMINATORS, son))
- prepare_block_for_update (son, insert_phi_p);
}
+/* Do a dominator walk starting at BB processing statements that
+ reference symbols in SSA operands. This is very similar to
+ mark_def_sites, but the scan handles statements whose operands may
+ already be SSA names.
+
+ If INSERT_PHI_P is true, mark those uses as live in the
+ corresponding block. This is later used by the PHI placement
+ algorithm to make PHI pruning decisions.
+
+ FIXME. Most of this would be unnecessary if we could associate a
+ symbol to all the SSA names that reference it. But that
+ sounds like it would be expensive to maintain. Still, it
+ would be interesting to see if it makes better sense to do
+ that. */
+static void
+prepare_block_for_update (basic_block bb, bool insert_phi_p)
+{
+ size_t sp = 0;
+ basic_block *worklist;
+
+ /* Allocate the worklist. */
+ worklist = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun));
+ /* Add the BB to the worklist. */
+ worklist[sp++] = bb;
+
+ while (sp)
+ {
+ basic_block bb;
+ basic_block son;
+
+ /* Pick a block from the worklist. */
+ bb = worklist[--sp];
+
+ prepare_block_for_update_1 (bb, insert_phi_p);
+
+ /* Now add all the blocks dominated by BB to the worklist. */
+ for (son = first_dom_son (CDI_DOMINATORS, bb);
+ son;
+ son = next_dom_son (CDI_DOMINATORS, son))
+ worklist[sp++] = son;
+ }
+ free (worklist);
+}
/* Helper for prepare_names_to_update. Mark all the use sites for
NAME as interesting. BLOCKS and INSERT_PHI_P are as in
use_operand_p use_p;
imm_use_iterator iter;
+ /* If we rename virtual operands do not update them. */
+ if (virtual_operand_p (name)
+ && cfun->gimple_df->rename_vops)
+ return;
+
FOR_EACH_IMM_USE_FAST (use_p, iter, name)
{
gimple *stmt = USE_STMT (use_p);
|| !bitmap_bit_p (names_to_release,
SSA_NAME_VERSION (name)));
+ /* If we rename virtual operands do not update them. */
+ if (virtual_operand_p (name)
+ && cfun->gimple_df->rename_vops)
+ return;
+
stmt = SSA_NAME_DEF_STMT (name);
bb = gimple_bb (stmt);
if (bb)
bitmap old_set;
bitmap_iterator bi;
- print_generic_expr (file, name, 0);
+ print_generic_expr (file, name);
fprintf (file, " -> { ");
old_set = names_replaced_by (name);
EXECUTE_IF_SET_IN_BITMAP (old_set, 0, i, bi)
{
- print_generic_expr (file, ssa_name (i), 0);
+ print_generic_expr (file, ssa_name (i));
fprintf (file, " ");
}
fprintf (file, "\nSSA names to release after updating the SSA web\n\n");
EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi)
{
- print_generic_expr (file, ssa_name (i), 0);
+ print_generic_expr (file, ssa_name (i));
fprintf (file, " ");
}
fprintf (file, "\n");
if (blocks_with_phis_to_rewrite)
EXECUTE_IF_SET_IN_BITMAP (blocks_with_phis_to_rewrite, 0, i, bi)
- {
- vec<gphi *> phis = phis_to_rewrite[i];
- phis.release ();
- phis_to_rewrite[i].create (0);
- }
+ phis_to_rewrite[i].release ();
BITMAP_FREE (blocks_with_phis_to_rewrite);
BITMAP_FREE (blocks_to_update);
if (SSA_NAME_IN_FREE_LIST (use))
{
- error ("statement uses released SSA name:");
+ error ("statement uses released SSA name");
debug_gimple_stmt (stmt);
fprintf (stderr, "The use of ");
- print_generic_expr (stderr, use, 0);
+ print_generic_expr (stderr, use);
fprintf (stderr," should have been replaced\n");
err = true;
}
OLD_SSA_NAMES. */
if (bitmap_first_set_bit (new_ssa_names) >= 0)
{
+ statistics_counter_event (cfun, "Incremental SSA update", 1);
+
prepare_names_to_update (insert_phi_p);
/* If all the names in NEW_SSA_NAMES had been marked for
/* Next, determine the block at which to start the renaming process. */
if (cfun->gimple_df->ssa_renaming_needed)
{
+ statistics_counter_event (cfun, "Symbol to SSA rewrite", 1);
+
/* If we rename bare symbols initialize the mapping to
auxiliar info we need to keep track of. */
var_infos = new hash_table<var_info_hasher> (47);
placement heuristics. */
prepare_block_for_update (start_bb, insert_phi_p);
+ tree name;
+
if (flag_checking)
- for (i = 1; i < num_ssa_names; ++i)
+ FOR_EACH_SSA_NAME (i, name, cfun)
{
- tree name = ssa_name (i);
- if (!name
- || virtual_operand_p (name))
+ if (virtual_operand_p (name))
continue;
/* For all but virtual operands, which do not have SSA names
will grow while we are traversing it (but it will not
gain any new members). Copy OLD_SSA_NAMES to a temporary
for traversal. */
- sbitmap tmp = sbitmap_alloc (SBITMAP_SIZE (old_ssa_names));
+ auto_sbitmap tmp (SBITMAP_SIZE (old_ssa_names));
bitmap_copy (tmp, old_ssa_names);
EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, sbi)
insert_updated_phi_nodes_for (ssa_name (i), dfs, blocks_to_update,
update_flags);
- sbitmap_free (tmp);
}
symbols_to_rename.qsort (insert_updated_phi_nodes_compare_uids);
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