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* [gcc(refs/users/aoliva/heads/testme)] Avoid visiting newly-created blocks in harden-conditionals
@ 2022-05-13 9:28 Alexandre Oliva
0 siblings, 0 replies; 4+ messages in thread
From: Alexandre Oliva @ 2022-05-13 9:28 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:917286f8147425013133d51bc1e62b0aff9c39c8
commit 917286f8147425013133d51bc1e62b0aff9c39c8
Author: Alexandre Oliva <oliva@adacore.com>
Date: Wed May 11 03:34:58 2022 -0300
Avoid visiting newly-created blocks in harden-conditionals
Reverse iteration over blocks, in gimple-harden-conditionals.cc, was
supposed to avoid visiting blocks introduced by hardening and
introducing further reversed conditionals and traps for them, but
newly-created blocks may be inserted before the current block, as
shown by the PR105455 testcase.
Use an auto_sbitmap to gather preexisting blocks that need visiting.
for gcc/ChangeLog
* gimple-harden-conditionals.cc: Include sbitmap.h.
(pass_harden_conditional_branches::execute): Skip new blocks.
(pass_harden_compares::execute): Likewise.
Diff:
---
gcc/gimple-harden-conditionals.cc | 417 ++++++++++++++++++++------------------
1 file changed, 220 insertions(+), 197 deletions(-)
diff --git a/gcc/gimple-harden-conditionals.cc b/gcc/gimple-harden-conditionals.cc
index 19ceb8a4bd6..79c0a5784ba 100644
--- a/gcc/gimple-harden-conditionals.cc
+++ b/gcc/gimple-harden-conditionals.cc
@@ -36,6 +36,7 @@ along with GCC; see the file COPYING3. If not see
#include "cfghooks.h"
#include "cfgloop.h"
#include "tree-eh.h"
+#include "sbitmap.h"
#include "diagnostic.h"
#include "intl.h"
@@ -303,9 +304,21 @@ insert_edge_check_and_trap (location_t loc, edge e,
unsigned int
pass_harden_conditional_branches::execute (function *fun)
{
+ /* Record the preexisting blocks, to avoid visiting newly-created
+ blocks. */
+ auto_sbitmap to_visit (last_basic_block_for_fn (fun));
+ bitmap_clear (to_visit);
+
basic_block bb;
- FOR_EACH_BB_REVERSE_FN (bb, fun)
+ FOR_EACH_BB_FN (bb, fun)
+ bitmap_set_bit (to_visit, bb->index);
+
+ sbitmap_iterator it;
+ unsigned i;
+ EXECUTE_IF_SET_IN_BITMAP (to_visit, 0, i, it)
{
+ bb = BASIC_BLOCK_FOR_FN (fun, i);
+
gimple_stmt_iterator gsi = gsi_last_bb (bb);
if (gsi_end_p (gsi))
@@ -385,205 +398,215 @@ non_eh_succ_edge (basic_block bb, edge *ehp = NULL)
unsigned int
pass_harden_compares::execute (function *fun)
{
+ /* Record the preexisting blocks, to avoid visiting newly-created
+ blocks. */
+ auto_sbitmap to_visit (last_basic_block_for_fn (fun));
+ bitmap_clear (to_visit);
+
basic_block bb;
- /* Go backwards over BBs and stmts, so that, even if we split the
- block multiple times to insert a cond_expr after each compare we
- find, we remain in the same block, visiting every preexisting
- stmt exactly once, and not visiting newly-added blocks or
- stmts. */
- FOR_EACH_BB_REVERSE_FN (bb, fun)
- for (gimple_stmt_iterator gsi = gsi_last_bb (bb);
- !gsi_end_p (gsi); gsi_prev (&gsi))
- {
- gassign *asgn = dyn_cast <gassign *> (gsi_stmt (gsi));
- if (!asgn)
- continue;
-
- /* Turn:
-
- z = x op y;
-
- into:
-
- z = x op y;
- z' = x' cop y';
- if (z == z') __builtin_trap ();
-
- where cop is a complementary boolean operation to op; and x'
- and y' hold the same value as x and y, but in a way that does
- not enable the compiler to optimize the redundant compare
- away.
- */
-
- enum tree_code op = gimple_assign_rhs_code (asgn);
-
- enum tree_code cop;
-
- switch (op)
- {
- case EQ_EXPR:
- case NE_EXPR:
- case GT_EXPR:
- case GE_EXPR:
- case LT_EXPR:
- case LE_EXPR:
- case LTGT_EXPR:
- case UNEQ_EXPR:
- case UNGT_EXPR:
- case UNGE_EXPR:
- case UNLT_EXPR:
- case UNLE_EXPR:
- case ORDERED_EXPR:
- case UNORDERED_EXPR:
- cop = invert_tree_comparison (op,
- HONOR_NANS
- (gimple_assign_rhs1 (asgn)));
-
- if (cop == ERROR_MARK)
- /* ??? Can we do better? */
- continue;
+ FOR_EACH_BB_FN (bb, fun)
+ bitmap_set_bit (to_visit, bb->index);
+
+ sbitmap_iterator it;
+ unsigned i;
+ EXECUTE_IF_SET_IN_BITMAP (to_visit, 0, i, it)
+ {
+ bb = BASIC_BLOCK_FOR_FN (fun, i);
- break;
-
- /* ??? Maybe handle these too? */
- case TRUTH_NOT_EXPR:
- /* ??? The code below assumes binary ops, it would have to
- be adjusted for TRUTH_NOT_EXPR, since it's unary. */
- case TRUTH_ANDIF_EXPR:
- case TRUTH_ORIF_EXPR:
- case TRUTH_AND_EXPR:
- case TRUTH_OR_EXPR:
- case TRUTH_XOR_EXPR:
- default:
+ for (gimple_stmt_iterator gsi = gsi_last_bb (bb);
+ !gsi_end_p (gsi); gsi_prev (&gsi))
+ {
+ gassign *asgn = dyn_cast <gassign *> (gsi_stmt (gsi));
+ if (!asgn)
+ continue;
+
+ /* Turn:
+
+ z = x op y;
+
+ into:
+
+ z = x op y;
+ z' = x' cop y';
+ if (z == z') __builtin_trap ();
+
+ where cop is a complementary boolean operation to op; and x'
+ and y' hold the same value as x and y, but in a way that does
+ not enable the compiler to optimize the redundant compare
+ away.
+ */
+
+ enum tree_code op = gimple_assign_rhs_code (asgn);
+
+ enum tree_code cop;
+
+ switch (op)
+ {
+ case EQ_EXPR:
+ case NE_EXPR:
+ case GT_EXPR:
+ case GE_EXPR:
+ case LT_EXPR:
+ case LE_EXPR:
+ case LTGT_EXPR:
+ case UNEQ_EXPR:
+ case UNGT_EXPR:
+ case UNGE_EXPR:
+ case UNLT_EXPR:
+ case UNLE_EXPR:
+ case ORDERED_EXPR:
+ case UNORDERED_EXPR:
+ cop = invert_tree_comparison (op,
+ HONOR_NANS
+ (gimple_assign_rhs1 (asgn)));
+
+ if (cop == ERROR_MARK)
+ /* ??? Can we do better? */
+ continue;
+
+ break;
+
+ /* ??? Maybe handle these too? */
+ case TRUTH_NOT_EXPR:
+ /* ??? The code below assumes binary ops, it would have to
+ be adjusted for TRUTH_NOT_EXPR, since it's unary. */
+ case TRUTH_ANDIF_EXPR:
+ case TRUTH_ORIF_EXPR:
+ case TRUTH_AND_EXPR:
+ case TRUTH_OR_EXPR:
+ case TRUTH_XOR_EXPR:
+ default:
+ continue;
+ }
+
+ /* These are the operands for the verification. */
+ tree lhs = gimple_assign_lhs (asgn);
+ tree op1 = gimple_assign_rhs1 (asgn);
+ tree op2 = gimple_assign_rhs2 (asgn);
+ location_t loc = gimple_location (asgn);
+
+ /* Vector booleans can't be used in conditional branches. ???
+ Can we do better? How to reduce compare and
+ reversed-compare result vectors to a single boolean? */
+ if (VECTOR_TYPE_P (TREE_TYPE (op1)))
continue;
- }
-
- /* These are the operands for the verification. */
- tree lhs = gimple_assign_lhs (asgn);
- tree op1 = gimple_assign_rhs1 (asgn);
- tree op2 = gimple_assign_rhs2 (asgn);
- location_t loc = gimple_location (asgn);
-
- /* Vector booleans can't be used in conditional branches. ???
- Can we do better? How to reduce compare and
- reversed-compare result vectors to a single boolean? */
- if (VECTOR_TYPE_P (TREE_TYPE (op1)))
- continue;
-
- /* useless_type_conversion_p enables conversions from 1-bit
- integer types to boolean to be discarded. */
- gcc_checking_assert (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE
- || (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
- && TYPE_PRECISION (TREE_TYPE (lhs)) == 1));
-
- tree rhs = copy_ssa_name (lhs);
-
- gimple_stmt_iterator gsi_split = gsi;
- /* Don't separate the original assignment from debug stmts
- that might be associated with it, and arrange to split the
- block after debug stmts, so as to make sure the split block
- won't be debug stmts only. */
- gsi_next_nondebug (&gsi_split);
-
- bool throwing_compare_p = stmt_ends_bb_p (asgn);
- if (throwing_compare_p)
- {
- basic_block nbb = split_edge (non_eh_succ_edge
- (gimple_bb (asgn)));
- gsi_split = gsi_start_bb (nbb);
-
- if (dump_file)
- fprintf (dump_file,
- "Splitting non-EH edge from block %i into %i"
- " after a throwing compare\n",
- gimple_bb (asgn)->index, nbb->index);
- }
-
- bool same_p = (op1 == op2);
- op1 = detach_value (loc, &gsi_split, op1);
- op2 = same_p ? op1 : detach_value (loc, &gsi_split, op2);
-
- gassign *asgnck = gimple_build_assign (rhs, cop, op1, op2);
- gimple_set_location (asgnck, loc);
- gsi_insert_before (&gsi_split, asgnck, GSI_SAME_STMT);
-
- /* We wish to insert a cond_expr after the compare, so arrange
- for it to be at the end of a block if it isn't, and for it
- to have a single successor in case there's more than
- one, as in PR104975. */
- if (!gsi_end_p (gsi_split)
- || !single_succ_p (gsi_bb (gsi_split)))
- {
- if (!gsi_end_p (gsi_split))
- gsi_prev (&gsi_split);
- else
- gsi_split = gsi_last_bb (gsi_bb (gsi_split));
- basic_block obb = gsi_bb (gsi_split);
- basic_block nbb = split_block (obb, gsi_stmt (gsi_split))->dest;
- gsi_next (&gsi_split);
- gcc_checking_assert (gsi_end_p (gsi_split));
-
- single_succ_edge (bb)->goto_locus = loc;
-
- if (dump_file)
- fprintf (dump_file,
- "Splitting block %i into %i"
- " before the conditional trap branch\n",
- obb->index, nbb->index);
- }
-
- /* If the check assignment must end a basic block, we can't
- insert the conditional branch in the same block, so split
- the block again, and prepare to insert the conditional
- branch in the new block.
-
- Also assign an EH region to the compare. Even though it's
- unlikely that the hardening compare will throw after the
- original compare didn't, the compiler won't even know that
- it's the same compare operands, so add the EH edge anyway. */
- if (throwing_compare_p)
- {
- add_stmt_to_eh_lp (asgnck, lookup_stmt_eh_lp (asgn));
- make_eh_edges (asgnck);
-
- edge ckeh;
- basic_block nbb = split_edge (non_eh_succ_edge
- (gimple_bb (asgnck), &ckeh));
- gsi_split = gsi_start_bb (nbb);
-
- if (dump_file)
- fprintf (dump_file,
- "Splitting non-EH edge from block %i into %i after"
- " the newly-inserted reversed throwing compare\n",
- gimple_bb (asgnck)->index, nbb->index);
-
- if (!gimple_seq_empty_p (phi_nodes (ckeh->dest)))
- {
- edge aseh;
- non_eh_succ_edge (gimple_bb (asgn), &aseh);
-
- gcc_checking_assert (aseh->dest == ckeh->dest);
-
- for (gphi_iterator psi = gsi_start_phis (ckeh->dest);
- !gsi_end_p (psi); gsi_next (&psi))
- {
- gphi *phi = psi.phi ();
- add_phi_arg (phi, PHI_ARG_DEF_FROM_EDGE (phi, aseh), ckeh,
- gimple_phi_arg_location_from_edge (phi, aseh));
- }
-
- if (dump_file)
- fprintf (dump_file,
- "Copying PHI args in EH block %i from %i to %i\n",
- aseh->dest->index, aseh->src->index, ckeh->src->index);
- }
- }
-
- gcc_checking_assert (single_succ_p (gsi_bb (gsi_split)));
-
- insert_check_and_trap (loc, &gsi_split, EDGE_TRUE_VALUE,
- EQ_EXPR, lhs, rhs);
- }
+
+ /* useless_type_conversion_p enables conversions from 1-bit
+ integer types to boolean to be discarded. */
+ gcc_checking_assert (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE
+ || (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
+ && TYPE_PRECISION (TREE_TYPE (lhs)) == 1));
+
+ tree rhs = copy_ssa_name (lhs);
+
+ gimple_stmt_iterator gsi_split = gsi;
+ /* Don't separate the original assignment from debug stmts
+ that might be associated with it, and arrange to split the
+ block after debug stmts, so as to make sure the split block
+ won't be debug stmts only. */
+ gsi_next_nondebug (&gsi_split);
+
+ bool throwing_compare_p = stmt_ends_bb_p (asgn);
+ if (throwing_compare_p)
+ {
+ basic_block nbb = split_edge (non_eh_succ_edge
+ (gimple_bb (asgn)));
+ gsi_split = gsi_start_bb (nbb);
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Splitting non-EH edge from block %i into %i"
+ " after a throwing compare\n",
+ gimple_bb (asgn)->index, nbb->index);
+ }
+
+ bool same_p = (op1 == op2);
+ op1 = detach_value (loc, &gsi_split, op1);
+ op2 = same_p ? op1 : detach_value (loc, &gsi_split, op2);
+
+ gassign *asgnck = gimple_build_assign (rhs, cop, op1, op2);
+ gimple_set_location (asgnck, loc);
+ gsi_insert_before (&gsi_split, asgnck, GSI_SAME_STMT);
+
+ /* We wish to insert a cond_expr after the compare, so arrange
+ for it to be at the end of a block if it isn't, and for it
+ to have a single successor in case there's more than
+ one, as in PR104975. */
+ if (!gsi_end_p (gsi_split)
+ || !single_succ_p (gsi_bb (gsi_split)))
+ {
+ if (!gsi_end_p (gsi_split))
+ gsi_prev (&gsi_split);
+ else
+ gsi_split = gsi_last_bb (gsi_bb (gsi_split));
+ basic_block obb = gsi_bb (gsi_split);
+ basic_block nbb = split_block (obb, gsi_stmt (gsi_split))->dest;
+ gsi_next (&gsi_split);
+ gcc_checking_assert (gsi_end_p (gsi_split));
+
+ single_succ_edge (bb)->goto_locus = loc;
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Splitting block %i into %i"
+ " before the conditional trap branch\n",
+ obb->index, nbb->index);
+ }
+
+ /* If the check assignment must end a basic block, we can't
+ insert the conditional branch in the same block, so split
+ the block again, and prepare to insert the conditional
+ branch in the new block.
+
+ Also assign an EH region to the compare. Even though it's
+ unlikely that the hardening compare will throw after the
+ original compare didn't, the compiler won't even know that
+ it's the same compare operands, so add the EH edge anyway. */
+ if (throwing_compare_p)
+ {
+ add_stmt_to_eh_lp (asgnck, lookup_stmt_eh_lp (asgn));
+ make_eh_edges (asgnck);
+
+ edge ckeh;
+ basic_block nbb = split_edge (non_eh_succ_edge
+ (gimple_bb (asgnck), &ckeh));
+ gsi_split = gsi_start_bb (nbb);
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Splitting non-EH edge from block %i into %i after"
+ " the newly-inserted reversed throwing compare\n",
+ gimple_bb (asgnck)->index, nbb->index);
+
+ if (!gimple_seq_empty_p (phi_nodes (ckeh->dest)))
+ {
+ edge aseh;
+ non_eh_succ_edge (gimple_bb (asgn), &aseh);
+
+ gcc_checking_assert (aseh->dest == ckeh->dest);
+
+ for (gphi_iterator psi = gsi_start_phis (ckeh->dest);
+ !gsi_end_p (psi); gsi_next (&psi))
+ {
+ gphi *phi = psi.phi ();
+ add_phi_arg (phi, PHI_ARG_DEF_FROM_EDGE (phi, aseh), ckeh,
+ gimple_phi_arg_location_from_edge (phi, aseh));
+ }
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Copying PHI args in EH block %i from %i to %i\n",
+ aseh->dest->index, aseh->src->index,
+ ckeh->src->index);
+ }
+ }
+
+ gcc_checking_assert (single_succ_p (gsi_bb (gsi_split)));
+
+ insert_check_and_trap (loc, &gsi_split, EDGE_TRUE_VALUE,
+ EQ_EXPR, lhs, rhs);
+ }
+ }
return 0;
}
^ permalink raw reply [flat|nested] 4+ messages in thread
* [gcc(refs/users/aoliva/heads/testme)] Avoid visiting newly-created blocks in harden-conditionals
@ 2022-05-13 7:33 Alexandre Oliva
0 siblings, 0 replies; 4+ messages in thread
From: Alexandre Oliva @ 2022-05-13 7:33 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:69a5699c03682be74f1664394a32f4240850220a
commit 69a5699c03682be74f1664394a32f4240850220a
Author: Alexandre Oliva <oliva@adacore.com>
Date: Wed May 11 03:34:58 2022 -0300
Avoid visiting newly-created blocks in harden-conditionals
Reverse iteration over blocks, in gimple-harden-conditionals.cc, was
supposed to avoid visiting blocks introduced by hardening and
introducing further reversed conditionals and traps for them, but
newly-created blocks may be inserted before the current block, as
shown by the PR105455 testcase.
Use an auto_sbitmap to gather preexisting blocks that need visiting.
for gcc/ChangeLog
* gimple-harden-conditionals.cc: Include sbitmap.h.
(pass_harden_conditional_branches::execute): Skip new blocks.
(pass_harden_compares::execute): Likewise.
Diff:
---
gcc/gimple-harden-conditionals.cc | 415 ++++++++++++++++++++------------------
1 file changed, 218 insertions(+), 197 deletions(-)
diff --git a/gcc/gimple-harden-conditionals.cc b/gcc/gimple-harden-conditionals.cc
index 19ceb8a4bd6..811914f13fe 100644
--- a/gcc/gimple-harden-conditionals.cc
+++ b/gcc/gimple-harden-conditionals.cc
@@ -36,6 +36,7 @@ along with GCC; see the file COPYING3. If not see
#include "cfghooks.h"
#include "cfgloop.h"
#include "tree-eh.h"
+#include "sbitmap.h"
#include "diagnostic.h"
#include "intl.h"
@@ -303,9 +304,20 @@ insert_edge_check_and_trap (location_t loc, edge e,
unsigned int
pass_harden_conditional_branches::execute (function *fun)
{
+ /* Record the preexisting blocks, to avoid visiting newly-created
+ blocks. */
+ auto_sbitmap to_visit (last_basic_block_for_fn (fun));
+
basic_block bb;
- FOR_EACH_BB_REVERSE_FN (bb, fun)
+ FOR_EACH_BB_FN (bb, fun)
+ bitmap_set_bit (to_visit, bb->index);
+
+ sbitmap_iterator it;
+ unsigned i;
+ EXECUTE_IF_SET_IN_BITMAP (to_visit, 0, i, it)
{
+ bb = BASIC_BLOCK_FOR_FN (fun, i);
+
gimple_stmt_iterator gsi = gsi_last_bb (bb);
if (gsi_end_p (gsi))
@@ -385,205 +397,214 @@ non_eh_succ_edge (basic_block bb, edge *ehp = NULL)
unsigned int
pass_harden_compares::execute (function *fun)
{
+ /* Record the preexisting blocks, to avoid visiting newly-created
+ blocks. */
+ auto_sbitmap to_visit (last_basic_block_for_fn (fun));
+
basic_block bb;
- /* Go backwards over BBs and stmts, so that, even if we split the
- block multiple times to insert a cond_expr after each compare we
- find, we remain in the same block, visiting every preexisting
- stmt exactly once, and not visiting newly-added blocks or
- stmts. */
- FOR_EACH_BB_REVERSE_FN (bb, fun)
- for (gimple_stmt_iterator gsi = gsi_last_bb (bb);
- !gsi_end_p (gsi); gsi_prev (&gsi))
- {
- gassign *asgn = dyn_cast <gassign *> (gsi_stmt (gsi));
- if (!asgn)
- continue;
-
- /* Turn:
-
- z = x op y;
-
- into:
-
- z = x op y;
- z' = x' cop y';
- if (z == z') __builtin_trap ();
-
- where cop is a complementary boolean operation to op; and x'
- and y' hold the same value as x and y, but in a way that does
- not enable the compiler to optimize the redundant compare
- away.
- */
-
- enum tree_code op = gimple_assign_rhs_code (asgn);
-
- enum tree_code cop;
-
- switch (op)
- {
- case EQ_EXPR:
- case NE_EXPR:
- case GT_EXPR:
- case GE_EXPR:
- case LT_EXPR:
- case LE_EXPR:
- case LTGT_EXPR:
- case UNEQ_EXPR:
- case UNGT_EXPR:
- case UNGE_EXPR:
- case UNLT_EXPR:
- case UNLE_EXPR:
- case ORDERED_EXPR:
- case UNORDERED_EXPR:
- cop = invert_tree_comparison (op,
- HONOR_NANS
- (gimple_assign_rhs1 (asgn)));
-
- if (cop == ERROR_MARK)
- /* ??? Can we do better? */
- continue;
+ FOR_EACH_BB_FN (bb, fun)
+ bitmap_set_bit (to_visit, bb->index);
+
+ sbitmap_iterator it;
+ unsigned i;
+ EXECUTE_IF_SET_IN_BITMAP (to_visit, 0, i, it)
+ {
+ bb = BASIC_BLOCK_FOR_FN (fun, i);
- break;
-
- /* ??? Maybe handle these too? */
- case TRUTH_NOT_EXPR:
- /* ??? The code below assumes binary ops, it would have to
- be adjusted for TRUTH_NOT_EXPR, since it's unary. */
- case TRUTH_ANDIF_EXPR:
- case TRUTH_ORIF_EXPR:
- case TRUTH_AND_EXPR:
- case TRUTH_OR_EXPR:
- case TRUTH_XOR_EXPR:
- default:
+ for (gimple_stmt_iterator gsi = gsi_last_bb (bb);
+ !gsi_end_p (gsi); gsi_prev (&gsi))
+ {
+ gassign *asgn = dyn_cast <gassign *> (gsi_stmt (gsi));
+ if (!asgn)
+ continue;
+
+ /* Turn:
+
+ z = x op y;
+
+ into:
+
+ z = x op y;
+ z' = x' cop y';
+ if (z == z') __builtin_trap ();
+
+ where cop is a complementary boolean operation to op; and x'
+ and y' hold the same value as x and y, but in a way that does
+ not enable the compiler to optimize the redundant compare
+ away.
+ */
+
+ enum tree_code op = gimple_assign_rhs_code (asgn);
+
+ enum tree_code cop;
+
+ switch (op)
+ {
+ case EQ_EXPR:
+ case NE_EXPR:
+ case GT_EXPR:
+ case GE_EXPR:
+ case LT_EXPR:
+ case LE_EXPR:
+ case LTGT_EXPR:
+ case UNEQ_EXPR:
+ case UNGT_EXPR:
+ case UNGE_EXPR:
+ case UNLT_EXPR:
+ case UNLE_EXPR:
+ case ORDERED_EXPR:
+ case UNORDERED_EXPR:
+ cop = invert_tree_comparison (op,
+ HONOR_NANS
+ (gimple_assign_rhs1 (asgn)));
+
+ if (cop == ERROR_MARK)
+ /* ??? Can we do better? */
+ continue;
+
+ break;
+
+ /* ??? Maybe handle these too? */
+ case TRUTH_NOT_EXPR:
+ /* ??? The code below assumes binary ops, it would have to
+ be adjusted for TRUTH_NOT_EXPR, since it's unary. */
+ case TRUTH_ANDIF_EXPR:
+ case TRUTH_ORIF_EXPR:
+ case TRUTH_AND_EXPR:
+ case TRUTH_OR_EXPR:
+ case TRUTH_XOR_EXPR:
+ default:
+ continue;
+ }
+
+ /* These are the operands for the verification. */
+ tree lhs = gimple_assign_lhs (asgn);
+ tree op1 = gimple_assign_rhs1 (asgn);
+ tree op2 = gimple_assign_rhs2 (asgn);
+ location_t loc = gimple_location (asgn);
+
+ /* Vector booleans can't be used in conditional branches. ???
+ Can we do better? How to reduce compare and
+ reversed-compare result vectors to a single boolean? */
+ if (VECTOR_TYPE_P (TREE_TYPE (op1)))
continue;
- }
-
- /* These are the operands for the verification. */
- tree lhs = gimple_assign_lhs (asgn);
- tree op1 = gimple_assign_rhs1 (asgn);
- tree op2 = gimple_assign_rhs2 (asgn);
- location_t loc = gimple_location (asgn);
-
- /* Vector booleans can't be used in conditional branches. ???
- Can we do better? How to reduce compare and
- reversed-compare result vectors to a single boolean? */
- if (VECTOR_TYPE_P (TREE_TYPE (op1)))
- continue;
-
- /* useless_type_conversion_p enables conversions from 1-bit
- integer types to boolean to be discarded. */
- gcc_checking_assert (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE
- || (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
- && TYPE_PRECISION (TREE_TYPE (lhs)) == 1));
-
- tree rhs = copy_ssa_name (lhs);
-
- gimple_stmt_iterator gsi_split = gsi;
- /* Don't separate the original assignment from debug stmts
- that might be associated with it, and arrange to split the
- block after debug stmts, so as to make sure the split block
- won't be debug stmts only. */
- gsi_next_nondebug (&gsi_split);
-
- bool throwing_compare_p = stmt_ends_bb_p (asgn);
- if (throwing_compare_p)
- {
- basic_block nbb = split_edge (non_eh_succ_edge
- (gimple_bb (asgn)));
- gsi_split = gsi_start_bb (nbb);
-
- if (dump_file)
- fprintf (dump_file,
- "Splitting non-EH edge from block %i into %i"
- " after a throwing compare\n",
- gimple_bb (asgn)->index, nbb->index);
- }
-
- bool same_p = (op1 == op2);
- op1 = detach_value (loc, &gsi_split, op1);
- op2 = same_p ? op1 : detach_value (loc, &gsi_split, op2);
-
- gassign *asgnck = gimple_build_assign (rhs, cop, op1, op2);
- gimple_set_location (asgnck, loc);
- gsi_insert_before (&gsi_split, asgnck, GSI_SAME_STMT);
-
- /* We wish to insert a cond_expr after the compare, so arrange
- for it to be at the end of a block if it isn't, and for it
- to have a single successor in case there's more than
- one, as in PR104975. */
- if (!gsi_end_p (gsi_split)
- || !single_succ_p (gsi_bb (gsi_split)))
- {
- if (!gsi_end_p (gsi_split))
- gsi_prev (&gsi_split);
- else
- gsi_split = gsi_last_bb (gsi_bb (gsi_split));
- basic_block obb = gsi_bb (gsi_split);
- basic_block nbb = split_block (obb, gsi_stmt (gsi_split))->dest;
- gsi_next (&gsi_split);
- gcc_checking_assert (gsi_end_p (gsi_split));
-
- single_succ_edge (bb)->goto_locus = loc;
-
- if (dump_file)
- fprintf (dump_file,
- "Splitting block %i into %i"
- " before the conditional trap branch\n",
- obb->index, nbb->index);
- }
-
- /* If the check assignment must end a basic block, we can't
- insert the conditional branch in the same block, so split
- the block again, and prepare to insert the conditional
- branch in the new block.
-
- Also assign an EH region to the compare. Even though it's
- unlikely that the hardening compare will throw after the
- original compare didn't, the compiler won't even know that
- it's the same compare operands, so add the EH edge anyway. */
- if (throwing_compare_p)
- {
- add_stmt_to_eh_lp (asgnck, lookup_stmt_eh_lp (asgn));
- make_eh_edges (asgnck);
-
- edge ckeh;
- basic_block nbb = split_edge (non_eh_succ_edge
- (gimple_bb (asgnck), &ckeh));
- gsi_split = gsi_start_bb (nbb);
-
- if (dump_file)
- fprintf (dump_file,
- "Splitting non-EH edge from block %i into %i after"
- " the newly-inserted reversed throwing compare\n",
- gimple_bb (asgnck)->index, nbb->index);
-
- if (!gimple_seq_empty_p (phi_nodes (ckeh->dest)))
- {
- edge aseh;
- non_eh_succ_edge (gimple_bb (asgn), &aseh);
-
- gcc_checking_assert (aseh->dest == ckeh->dest);
-
- for (gphi_iterator psi = gsi_start_phis (ckeh->dest);
- !gsi_end_p (psi); gsi_next (&psi))
- {
- gphi *phi = psi.phi ();
- add_phi_arg (phi, PHI_ARG_DEF_FROM_EDGE (phi, aseh), ckeh,
- gimple_phi_arg_location_from_edge (phi, aseh));
- }
-
- if (dump_file)
- fprintf (dump_file,
- "Copying PHI args in EH block %i from %i to %i\n",
- aseh->dest->index, aseh->src->index, ckeh->src->index);
- }
- }
-
- gcc_checking_assert (single_succ_p (gsi_bb (gsi_split)));
-
- insert_check_and_trap (loc, &gsi_split, EDGE_TRUE_VALUE,
- EQ_EXPR, lhs, rhs);
- }
+
+ /* useless_type_conversion_p enables conversions from 1-bit
+ integer types to boolean to be discarded. */
+ gcc_checking_assert (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE
+ || (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
+ && TYPE_PRECISION (TREE_TYPE (lhs)) == 1));
+
+ tree rhs = copy_ssa_name (lhs);
+
+ gimple_stmt_iterator gsi_split = gsi;
+ /* Don't separate the original assignment from debug stmts
+ that might be associated with it, and arrange to split the
+ block after debug stmts, so as to make sure the split block
+ won't be debug stmts only. */
+ gsi_next_nondebug (&gsi_split);
+
+ bool throwing_compare_p = stmt_ends_bb_p (asgn);
+ if (throwing_compare_p)
+ {
+ basic_block nbb = split_edge (non_eh_succ_edge
+ (gimple_bb (asgn)));
+ gsi_split = gsi_start_bb (nbb);
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Splitting non-EH edge from block %i into %i"
+ " after a throwing compare\n",
+ gimple_bb (asgn)->index, nbb->index);
+ }
+
+ bool same_p = (op1 == op2);
+ op1 = detach_value (loc, &gsi_split, op1);
+ op2 = same_p ? op1 : detach_value (loc, &gsi_split, op2);
+
+ gassign *asgnck = gimple_build_assign (rhs, cop, op1, op2);
+ gimple_set_location (asgnck, loc);
+ gsi_insert_before (&gsi_split, asgnck, GSI_SAME_STMT);
+
+ /* We wish to insert a cond_expr after the compare, so arrange
+ for it to be at the end of a block if it isn't, and for it
+ to have a single successor in case there's more than
+ one, as in PR104975. */
+ if (!gsi_end_p (gsi_split)
+ || !single_succ_p (gsi_bb (gsi_split)))
+ {
+ if (!gsi_end_p (gsi_split))
+ gsi_prev (&gsi_split);
+ else
+ gsi_split = gsi_last_bb (gsi_bb (gsi_split));
+ basic_block obb = gsi_bb (gsi_split);
+ basic_block nbb = split_block (obb, gsi_stmt (gsi_split))->dest;
+ gsi_next (&gsi_split);
+ gcc_checking_assert (gsi_end_p (gsi_split));
+
+ single_succ_edge (bb)->goto_locus = loc;
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Splitting block %i into %i"
+ " before the conditional trap branch\n",
+ obb->index, nbb->index);
+ }
+
+ /* If the check assignment must end a basic block, we can't
+ insert the conditional branch in the same block, so split
+ the block again, and prepare to insert the conditional
+ branch in the new block.
+
+ Also assign an EH region to the compare. Even though it's
+ unlikely that the hardening compare will throw after the
+ original compare didn't, the compiler won't even know that
+ it's the same compare operands, so add the EH edge anyway. */
+ if (throwing_compare_p)
+ {
+ add_stmt_to_eh_lp (asgnck, lookup_stmt_eh_lp (asgn));
+ make_eh_edges (asgnck);
+
+ edge ckeh;
+ basic_block nbb = split_edge (non_eh_succ_edge
+ (gimple_bb (asgnck), &ckeh));
+ gsi_split = gsi_start_bb (nbb);
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Splitting non-EH edge from block %i into %i after"
+ " the newly-inserted reversed throwing compare\n",
+ gimple_bb (asgnck)->index, nbb->index);
+
+ if (!gimple_seq_empty_p (phi_nodes (ckeh->dest)))
+ {
+ edge aseh;
+ non_eh_succ_edge (gimple_bb (asgn), &aseh);
+
+ gcc_checking_assert (aseh->dest == ckeh->dest);
+
+ for (gphi_iterator psi = gsi_start_phis (ckeh->dest);
+ !gsi_end_p (psi); gsi_next (&psi))
+ {
+ gphi *phi = psi.phi ();
+ add_phi_arg (phi, PHI_ARG_DEF_FROM_EDGE (phi, aseh), ckeh,
+ gimple_phi_arg_location_from_edge (phi, aseh));
+ }
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Copying PHI args in EH block %i from %i to %i\n",
+ aseh->dest->index, aseh->src->index,
+ ckeh->src->index);
+ }
+ }
+
+ gcc_checking_assert (single_succ_p (gsi_bb (gsi_split)));
+
+ insert_check_and_trap (loc, &gsi_split, EDGE_TRUE_VALUE,
+ EQ_EXPR, lhs, rhs);
+ }
+ }
return 0;
}
^ permalink raw reply [flat|nested] 4+ messages in thread
* [gcc(refs/users/aoliva/heads/testme)] Avoid visiting newly-created blocks in harden-conditionals
@ 2022-05-11 9:36 Alexandre Oliva
0 siblings, 0 replies; 4+ messages in thread
From: Alexandre Oliva @ 2022-05-11 9:36 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:af6890696c1a4ea8f30d269f8eb7a3dbd6ed24ee
commit af6890696c1a4ea8f30d269f8eb7a3dbd6ed24ee
Author: Alexandre Oliva <oliva@adacore.com>
Date: Wed May 11 03:34:58 2022 -0300
Avoid visiting newly-created blocks in harden-conditionals
Reverse iteration over blocks, in gimple-harden-conditionals.cc, was
supposed to avoid visiting blocks introduced by hardening and
introducing further reversed conditionals and traps for them, but
newly-created blocks may be inserted before the current block, as
shown by the PR105455 testcase.
New blocks use and increment last block number, so test the block
index against the initial last block number to skip new blocks.
for gcc/ChangeLog
* gimple-harden-conditionals.cc
(pass_harden_conditional_branches::execute): Skip new blocks.
(pass_harden_compares::execute): Likewise.
Diff:
---
gcc/gimple-harden-conditionals.cc | 401 ++++++++++++++++++++------------------
1 file changed, 211 insertions(+), 190 deletions(-)
diff --git a/gcc/gimple-harden-conditionals.cc b/gcc/gimple-harden-conditionals.cc
index c7e5e077a74..28c4810f0a7 100644
--- a/gcc/gimple-harden-conditionals.cc
+++ b/gcc/gimple-harden-conditionals.cc
@@ -301,9 +301,18 @@ insert_edge_check_and_trap (location_t loc, edge e,
unsigned int
pass_harden_conditional_branches::execute (function *fun)
{
+ int orig_last_block = last_basic_block_for_fn (fun);
+
basic_block bb;
FOR_EACH_BB_REVERSE_FN (bb, fun)
{
+ /* Despite our backwards iteration on basic blocks, sometimes
+ split_edge will insert the new block before the block we're
+ hardening, and then we'd harden the hardening block. Skip
+ newly-created blocks to avoid that. */
+ if (bb->index >= orig_last_block)
+ continue;
+
gimple_stmt_iterator gsi = gsi_last_bb (bb);
if (gsi_end_p (gsi))
@@ -383,6 +392,8 @@ non_eh_succ_edge (basic_block bb, edge *ehp = NULL)
unsigned int
pass_harden_compares::execute (function *fun)
{
+ int orig_last_block = last_basic_block_for_fn (fun);
+
basic_block bb;
/* Go backwards over BBs and stmts, so that, even if we split the
block multiple times to insert a cond_expr after each compare we
@@ -390,198 +401,208 @@ pass_harden_compares::execute (function *fun)
stmt exactly once, and not visiting newly-added blocks or
stmts. */
FOR_EACH_BB_REVERSE_FN (bb, fun)
- for (gimple_stmt_iterator gsi = gsi_last_bb (bb);
- !gsi_end_p (gsi); gsi_prev (&gsi))
- {
- gassign *asgn = dyn_cast <gassign *> (gsi_stmt (gsi));
- if (!asgn)
- continue;
-
- /* Turn:
-
- z = x op y;
-
- into:
-
- z = x op y;
- z' = x' cop y';
- if (z == z') __builtin_trap ();
-
- where cop is a complementary boolean operation to op; and x'
- and y' hold the same value as x and y, but in a way that does
- not enable the compiler to optimize the redundant compare
- away.
- */
-
- enum tree_code op = gimple_assign_rhs_code (asgn);
-
- enum tree_code cop;
-
- switch (op)
- {
- case EQ_EXPR:
- case NE_EXPR:
- case GT_EXPR:
- case GE_EXPR:
- case LT_EXPR:
- case LE_EXPR:
- case LTGT_EXPR:
- case UNEQ_EXPR:
- case UNGT_EXPR:
- case UNGE_EXPR:
- case UNLT_EXPR:
- case UNLE_EXPR:
- case ORDERED_EXPR:
- case UNORDERED_EXPR:
- cop = invert_tree_comparison (op,
- HONOR_NANS
- (gimple_assign_rhs1 (asgn)));
-
- if (cop == ERROR_MARK)
- /* ??? Can we do better? */
- continue;
+ {
+ /* Despite our backwards iteration on basic blocks, sometimes
+ split_edge will insert the new block before the block we're
+ hardening, and then we'd harden the hardening block. Skip
+ newly-created blocks to avoid that. */
+ if (bb->index >= orig_last_block)
+ continue;
- break;
-
- /* ??? Maybe handle these too? */
- case TRUTH_NOT_EXPR:
- /* ??? The code below assumes binary ops, it would have to
- be adjusted for TRUTH_NOT_EXPR, since it's unary. */
- case TRUTH_ANDIF_EXPR:
- case TRUTH_ORIF_EXPR:
- case TRUTH_AND_EXPR:
- case TRUTH_OR_EXPR:
- case TRUTH_XOR_EXPR:
- default:
+ for (gimple_stmt_iterator gsi = gsi_last_bb (bb);
+ !gsi_end_p (gsi); gsi_prev (&gsi))
+ {
+ gassign *asgn = dyn_cast <gassign *> (gsi_stmt (gsi));
+ if (!asgn)
+ continue;
+
+ /* Turn:
+
+ z = x op y;
+
+ into:
+
+ z = x op y;
+ z' = x' cop y';
+ if (z == z') __builtin_trap ();
+
+ where cop is a complementary boolean operation to op; and x'
+ and y' hold the same value as x and y, but in a way that does
+ not enable the compiler to optimize the redundant compare
+ away.
+ */
+
+ enum tree_code op = gimple_assign_rhs_code (asgn);
+
+ enum tree_code cop;
+
+ switch (op)
+ {
+ case EQ_EXPR:
+ case NE_EXPR:
+ case GT_EXPR:
+ case GE_EXPR:
+ case LT_EXPR:
+ case LE_EXPR:
+ case LTGT_EXPR:
+ case UNEQ_EXPR:
+ case UNGT_EXPR:
+ case UNGE_EXPR:
+ case UNLT_EXPR:
+ case UNLE_EXPR:
+ case ORDERED_EXPR:
+ case UNORDERED_EXPR:
+ cop = invert_tree_comparison (op,
+ HONOR_NANS
+ (gimple_assign_rhs1 (asgn)));
+
+ if (cop == ERROR_MARK)
+ /* ??? Can we do better? */
+ continue;
+
+ break;
+
+ /* ??? Maybe handle these too? */
+ case TRUTH_NOT_EXPR:
+ /* ??? The code below assumes binary ops, it would have to
+ be adjusted for TRUTH_NOT_EXPR, since it's unary. */
+ case TRUTH_ANDIF_EXPR:
+ case TRUTH_ORIF_EXPR:
+ case TRUTH_AND_EXPR:
+ case TRUTH_OR_EXPR:
+ case TRUTH_XOR_EXPR:
+ default:
+ continue;
+ }
+
+ /* These are the operands for the verification. */
+ tree lhs = gimple_assign_lhs (asgn);
+ tree op1 = gimple_assign_rhs1 (asgn);
+ tree op2 = gimple_assign_rhs2 (asgn);
+ location_t loc = gimple_location (asgn);
+
+ /* Vector booleans can't be used in conditional branches. ???
+ Can we do better? How to reduce compare and
+ reversed-compare result vectors to a single boolean? */
+ if (VECTOR_TYPE_P (TREE_TYPE (op1)))
continue;
- }
-
- /* These are the operands for the verification. */
- tree lhs = gimple_assign_lhs (asgn);
- tree op1 = gimple_assign_rhs1 (asgn);
- tree op2 = gimple_assign_rhs2 (asgn);
- location_t loc = gimple_location (asgn);
-
- /* Vector booleans can't be used in conditional branches. ???
- Can we do better? How to reduce compare and
- reversed-compare result vectors to a single boolean? */
- if (VECTOR_TYPE_P (TREE_TYPE (op1)))
- continue;
-
- /* useless_type_conversion_p enables conversions from 1-bit
- integer types to boolean to be discarded. */
- gcc_checking_assert (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE
- || (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
- && TYPE_PRECISION (TREE_TYPE (lhs)) == 1));
-
- tree rhs = copy_ssa_name (lhs);
-
- gimple_stmt_iterator gsi_split = gsi;
- /* Don't separate the original assignment from debug stmts
- that might be associated with it, and arrange to split the
- block after debug stmts, so as to make sure the split block
- won't be debug stmts only. */
- gsi_next_nondebug (&gsi_split);
-
- bool throwing_compare_p = stmt_ends_bb_p (asgn);
- if (throwing_compare_p)
- {
- basic_block nbb = split_edge (non_eh_succ_edge
- (gimple_bb (asgn)));
- gsi_split = gsi_start_bb (nbb);
-
- if (dump_file)
- fprintf (dump_file,
- "Splitting non-EH edge from block %i into %i"
- " after a throwing compare\n",
- gimple_bb (asgn)->index, nbb->index);
- }
-
- bool same_p = (op1 == op2);
- op1 = detach_value (loc, &gsi_split, op1);
- op2 = same_p ? op1 : detach_value (loc, &gsi_split, op2);
-
- gassign *asgnck = gimple_build_assign (rhs, cop, op1, op2);
- gimple_set_location (asgnck, loc);
- gsi_insert_before (&gsi_split, asgnck, GSI_SAME_STMT);
-
- /* We wish to insert a cond_expr after the compare, so arrange
- for it to be at the end of a block if it isn't, and for it
- to have a single successor in case there's more than
- one, as in PR104975. */
- if (!gsi_end_p (gsi_split)
- || !single_succ_p (gsi_bb (gsi_split)))
- {
- if (!gsi_end_p (gsi_split))
- gsi_prev (&gsi_split);
- else
- gsi_split = gsi_last_bb (gsi_bb (gsi_split));
- basic_block obb = gsi_bb (gsi_split);
- basic_block nbb = split_block (obb, gsi_stmt (gsi_split))->dest;
- gsi_next (&gsi_split);
- gcc_checking_assert (gsi_end_p (gsi_split));
-
- single_succ_edge (bb)->goto_locus = loc;
-
- if (dump_file)
- fprintf (dump_file,
- "Splitting block %i into %i"
- " before the conditional trap branch\n",
- obb->index, nbb->index);
- }
-
- /* If the check assignment must end a basic block, we can't
- insert the conditional branch in the same block, so split
- the block again, and prepare to insert the conditional
- branch in the new block.
-
- Also assign an EH region to the compare. Even though it's
- unlikely that the hardening compare will throw after the
- original compare didn't, the compiler won't even know that
- it's the same compare operands, so add the EH edge anyway. */
- if (throwing_compare_p)
- {
- add_stmt_to_eh_lp (asgnck, lookup_stmt_eh_lp (asgn));
- make_eh_edges (asgnck);
-
- edge ckeh;
- basic_block nbb = split_edge (non_eh_succ_edge
- (gimple_bb (asgnck), &ckeh));
- gsi_split = gsi_start_bb (nbb);
-
- if (dump_file)
- fprintf (dump_file,
- "Splitting non-EH edge from block %i into %i after"
- " the newly-inserted reversed throwing compare\n",
- gimple_bb (asgnck)->index, nbb->index);
-
- if (!gimple_seq_empty_p (phi_nodes (ckeh->dest)))
- {
- edge aseh;
- non_eh_succ_edge (gimple_bb (asgn), &aseh);
-
- gcc_checking_assert (aseh->dest == ckeh->dest);
-
- for (gphi_iterator psi = gsi_start_phis (ckeh->dest);
- !gsi_end_p (psi); gsi_next (&psi))
- {
- gphi *phi = psi.phi ();
- add_phi_arg (phi, PHI_ARG_DEF_FROM_EDGE (phi, aseh), ckeh,
- gimple_phi_arg_location_from_edge (phi, aseh));
- }
-
- if (dump_file)
- fprintf (dump_file,
- "Copying PHI args in EH block %i from %i to %i\n",
- aseh->dest->index, aseh->src->index, ckeh->src->index);
- }
- }
-
- gcc_checking_assert (single_succ_p (gsi_bb (gsi_split)));
-
- insert_check_and_trap (loc, &gsi_split, EDGE_TRUE_VALUE,
- EQ_EXPR, lhs, rhs);
- }
+
+ /* useless_type_conversion_p enables conversions from 1-bit
+ integer types to boolean to be discarded. */
+ gcc_checking_assert (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE
+ || (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
+ && TYPE_PRECISION (TREE_TYPE (lhs)) == 1));
+
+ tree rhs = copy_ssa_name (lhs);
+
+ gimple_stmt_iterator gsi_split = gsi;
+ /* Don't separate the original assignment from debug stmts
+ that might be associated with it, and arrange to split the
+ block after debug stmts, so as to make sure the split block
+ won't be debug stmts only. */
+ gsi_next_nondebug (&gsi_split);
+
+ bool throwing_compare_p = stmt_ends_bb_p (asgn);
+ if (throwing_compare_p)
+ {
+ basic_block nbb = split_edge (non_eh_succ_edge
+ (gimple_bb (asgn)));
+ gsi_split = gsi_start_bb (nbb);
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Splitting non-EH edge from block %i into %i"
+ " after a throwing compare\n",
+ gimple_bb (asgn)->index, nbb->index);
+ }
+
+ bool same_p = (op1 == op2);
+ op1 = detach_value (loc, &gsi_split, op1);
+ op2 = same_p ? op1 : detach_value (loc, &gsi_split, op2);
+
+ gassign *asgnck = gimple_build_assign (rhs, cop, op1, op2);
+ gimple_set_location (asgnck, loc);
+ gsi_insert_before (&gsi_split, asgnck, GSI_SAME_STMT);
+
+ /* We wish to insert a cond_expr after the compare, so arrange
+ for it to be at the end of a block if it isn't, and for it
+ to have a single successor in case there's more than
+ one, as in PR104975. */
+ if (!gsi_end_p (gsi_split)
+ || !single_succ_p (gsi_bb (gsi_split)))
+ {
+ if (!gsi_end_p (gsi_split))
+ gsi_prev (&gsi_split);
+ else
+ gsi_split = gsi_last_bb (gsi_bb (gsi_split));
+ basic_block obb = gsi_bb (gsi_split);
+ basic_block nbb = split_block (obb, gsi_stmt (gsi_split))->dest;
+ gsi_next (&gsi_split);
+ gcc_checking_assert (gsi_end_p (gsi_split));
+
+ single_succ_edge (bb)->goto_locus = loc;
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Splitting block %i into %i"
+ " before the conditional trap branch\n",
+ obb->index, nbb->index);
+ }
+
+ /* If the check assignment must end a basic block, we can't
+ insert the conditional branch in the same block, so split
+ the block again, and prepare to insert the conditional
+ branch in the new block.
+
+ Also assign an EH region to the compare. Even though it's
+ unlikely that the hardening compare will throw after the
+ original compare didn't, the compiler won't even know that
+ it's the same compare operands, so add the EH edge anyway. */
+ if (throwing_compare_p)
+ {
+ add_stmt_to_eh_lp (asgnck, lookup_stmt_eh_lp (asgn));
+ make_eh_edges (asgnck);
+
+ edge ckeh;
+ basic_block nbb = split_edge (non_eh_succ_edge
+ (gimple_bb (asgnck), &ckeh));
+ gsi_split = gsi_start_bb (nbb);
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Splitting non-EH edge from block %i into %i after"
+ " the newly-inserted reversed throwing compare\n",
+ gimple_bb (asgnck)->index, nbb->index);
+
+ if (!gimple_seq_empty_p (phi_nodes (ckeh->dest)))
+ {
+ edge aseh;
+ non_eh_succ_edge (gimple_bb (asgn), &aseh);
+
+ gcc_checking_assert (aseh->dest == ckeh->dest);
+
+ for (gphi_iterator psi = gsi_start_phis (ckeh->dest);
+ !gsi_end_p (psi); gsi_next (&psi))
+ {
+ gphi *phi = psi.phi ();
+ add_phi_arg (phi, PHI_ARG_DEF_FROM_EDGE (phi, aseh), ckeh,
+ gimple_phi_arg_location_from_edge (phi, aseh));
+ }
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Copying PHI args in EH block %i from %i to %i\n",
+ aseh->dest->index, aseh->src->index,
+ ckeh->src->index);
+ }
+ }
+
+ gcc_checking_assert (single_succ_p (gsi_bb (gsi_split)));
+
+ insert_check_and_trap (loc, &gsi_split, EDGE_TRUE_VALUE,
+ EQ_EXPR, lhs, rhs);
+ }
+ }
return 0;
}
^ permalink raw reply [flat|nested] 4+ messages in thread
* [gcc(refs/users/aoliva/heads/testme)] Avoid visiting newly-created blocks in harden-conditionals
@ 2022-05-11 7:32 Alexandre Oliva
0 siblings, 0 replies; 4+ messages in thread
From: Alexandre Oliva @ 2022-05-11 7:32 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:91a0ae071116f11a8430b8434fdb5dd8d1e6d605
commit 91a0ae071116f11a8430b8434fdb5dd8d1e6d605
Author: Alexandre Oliva <oliva@adacore.com>
Date: Wed May 11 03:34:58 2022 -0300
Avoid visiting newly-created blocks in harden-conditionals
Diff:
---
gcc/gimple-harden-conditionals.cc | 401 ++++++++++++++++++++------------------
1 file changed, 211 insertions(+), 190 deletions(-)
diff --git a/gcc/gimple-harden-conditionals.cc b/gcc/gimple-harden-conditionals.cc
index c7e5e077a74..28c4810f0a7 100644
--- a/gcc/gimple-harden-conditionals.cc
+++ b/gcc/gimple-harden-conditionals.cc
@@ -301,9 +301,18 @@ insert_edge_check_and_trap (location_t loc, edge e,
unsigned int
pass_harden_conditional_branches::execute (function *fun)
{
+ int orig_last_block = last_basic_block_for_fn (fun);
+
basic_block bb;
FOR_EACH_BB_REVERSE_FN (bb, fun)
{
+ /* Despite our backwards iteration on basic blocks, sometimes
+ split_edge will insert the new block before the block we're
+ hardening, and then we'd harden the hardening block. Skip
+ newly-created blocks to avoid that. */
+ if (bb->index >= orig_last_block)
+ continue;
+
gimple_stmt_iterator gsi = gsi_last_bb (bb);
if (gsi_end_p (gsi))
@@ -383,6 +392,8 @@ non_eh_succ_edge (basic_block bb, edge *ehp = NULL)
unsigned int
pass_harden_compares::execute (function *fun)
{
+ int orig_last_block = last_basic_block_for_fn (fun);
+
basic_block bb;
/* Go backwards over BBs and stmts, so that, even if we split the
block multiple times to insert a cond_expr after each compare we
@@ -390,198 +401,208 @@ pass_harden_compares::execute (function *fun)
stmt exactly once, and not visiting newly-added blocks or
stmts. */
FOR_EACH_BB_REVERSE_FN (bb, fun)
- for (gimple_stmt_iterator gsi = gsi_last_bb (bb);
- !gsi_end_p (gsi); gsi_prev (&gsi))
- {
- gassign *asgn = dyn_cast <gassign *> (gsi_stmt (gsi));
- if (!asgn)
- continue;
-
- /* Turn:
-
- z = x op y;
-
- into:
-
- z = x op y;
- z' = x' cop y';
- if (z == z') __builtin_trap ();
-
- where cop is a complementary boolean operation to op; and x'
- and y' hold the same value as x and y, but in a way that does
- not enable the compiler to optimize the redundant compare
- away.
- */
-
- enum tree_code op = gimple_assign_rhs_code (asgn);
-
- enum tree_code cop;
-
- switch (op)
- {
- case EQ_EXPR:
- case NE_EXPR:
- case GT_EXPR:
- case GE_EXPR:
- case LT_EXPR:
- case LE_EXPR:
- case LTGT_EXPR:
- case UNEQ_EXPR:
- case UNGT_EXPR:
- case UNGE_EXPR:
- case UNLT_EXPR:
- case UNLE_EXPR:
- case ORDERED_EXPR:
- case UNORDERED_EXPR:
- cop = invert_tree_comparison (op,
- HONOR_NANS
- (gimple_assign_rhs1 (asgn)));
-
- if (cop == ERROR_MARK)
- /* ??? Can we do better? */
- continue;
+ {
+ /* Despite our backwards iteration on basic blocks, sometimes
+ split_edge will insert the new block before the block we're
+ hardening, and then we'd harden the hardening block. Skip
+ newly-created blocks to avoid that. */
+ if (bb->index >= orig_last_block)
+ continue;
- break;
-
- /* ??? Maybe handle these too? */
- case TRUTH_NOT_EXPR:
- /* ??? The code below assumes binary ops, it would have to
- be adjusted for TRUTH_NOT_EXPR, since it's unary. */
- case TRUTH_ANDIF_EXPR:
- case TRUTH_ORIF_EXPR:
- case TRUTH_AND_EXPR:
- case TRUTH_OR_EXPR:
- case TRUTH_XOR_EXPR:
- default:
+ for (gimple_stmt_iterator gsi = gsi_last_bb (bb);
+ !gsi_end_p (gsi); gsi_prev (&gsi))
+ {
+ gassign *asgn = dyn_cast <gassign *> (gsi_stmt (gsi));
+ if (!asgn)
+ continue;
+
+ /* Turn:
+
+ z = x op y;
+
+ into:
+
+ z = x op y;
+ z' = x' cop y';
+ if (z == z') __builtin_trap ();
+
+ where cop is a complementary boolean operation to op; and x'
+ and y' hold the same value as x and y, but in a way that does
+ not enable the compiler to optimize the redundant compare
+ away.
+ */
+
+ enum tree_code op = gimple_assign_rhs_code (asgn);
+
+ enum tree_code cop;
+
+ switch (op)
+ {
+ case EQ_EXPR:
+ case NE_EXPR:
+ case GT_EXPR:
+ case GE_EXPR:
+ case LT_EXPR:
+ case LE_EXPR:
+ case LTGT_EXPR:
+ case UNEQ_EXPR:
+ case UNGT_EXPR:
+ case UNGE_EXPR:
+ case UNLT_EXPR:
+ case UNLE_EXPR:
+ case ORDERED_EXPR:
+ case UNORDERED_EXPR:
+ cop = invert_tree_comparison (op,
+ HONOR_NANS
+ (gimple_assign_rhs1 (asgn)));
+
+ if (cop == ERROR_MARK)
+ /* ??? Can we do better? */
+ continue;
+
+ break;
+
+ /* ??? Maybe handle these too? */
+ case TRUTH_NOT_EXPR:
+ /* ??? The code below assumes binary ops, it would have to
+ be adjusted for TRUTH_NOT_EXPR, since it's unary. */
+ case TRUTH_ANDIF_EXPR:
+ case TRUTH_ORIF_EXPR:
+ case TRUTH_AND_EXPR:
+ case TRUTH_OR_EXPR:
+ case TRUTH_XOR_EXPR:
+ default:
+ continue;
+ }
+
+ /* These are the operands for the verification. */
+ tree lhs = gimple_assign_lhs (asgn);
+ tree op1 = gimple_assign_rhs1 (asgn);
+ tree op2 = gimple_assign_rhs2 (asgn);
+ location_t loc = gimple_location (asgn);
+
+ /* Vector booleans can't be used in conditional branches. ???
+ Can we do better? How to reduce compare and
+ reversed-compare result vectors to a single boolean? */
+ if (VECTOR_TYPE_P (TREE_TYPE (op1)))
continue;
- }
-
- /* These are the operands for the verification. */
- tree lhs = gimple_assign_lhs (asgn);
- tree op1 = gimple_assign_rhs1 (asgn);
- tree op2 = gimple_assign_rhs2 (asgn);
- location_t loc = gimple_location (asgn);
-
- /* Vector booleans can't be used in conditional branches. ???
- Can we do better? How to reduce compare and
- reversed-compare result vectors to a single boolean? */
- if (VECTOR_TYPE_P (TREE_TYPE (op1)))
- continue;
-
- /* useless_type_conversion_p enables conversions from 1-bit
- integer types to boolean to be discarded. */
- gcc_checking_assert (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE
- || (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
- && TYPE_PRECISION (TREE_TYPE (lhs)) == 1));
-
- tree rhs = copy_ssa_name (lhs);
-
- gimple_stmt_iterator gsi_split = gsi;
- /* Don't separate the original assignment from debug stmts
- that might be associated with it, and arrange to split the
- block after debug stmts, so as to make sure the split block
- won't be debug stmts only. */
- gsi_next_nondebug (&gsi_split);
-
- bool throwing_compare_p = stmt_ends_bb_p (asgn);
- if (throwing_compare_p)
- {
- basic_block nbb = split_edge (non_eh_succ_edge
- (gimple_bb (asgn)));
- gsi_split = gsi_start_bb (nbb);
-
- if (dump_file)
- fprintf (dump_file,
- "Splitting non-EH edge from block %i into %i"
- " after a throwing compare\n",
- gimple_bb (asgn)->index, nbb->index);
- }
-
- bool same_p = (op1 == op2);
- op1 = detach_value (loc, &gsi_split, op1);
- op2 = same_p ? op1 : detach_value (loc, &gsi_split, op2);
-
- gassign *asgnck = gimple_build_assign (rhs, cop, op1, op2);
- gimple_set_location (asgnck, loc);
- gsi_insert_before (&gsi_split, asgnck, GSI_SAME_STMT);
-
- /* We wish to insert a cond_expr after the compare, so arrange
- for it to be at the end of a block if it isn't, and for it
- to have a single successor in case there's more than
- one, as in PR104975. */
- if (!gsi_end_p (gsi_split)
- || !single_succ_p (gsi_bb (gsi_split)))
- {
- if (!gsi_end_p (gsi_split))
- gsi_prev (&gsi_split);
- else
- gsi_split = gsi_last_bb (gsi_bb (gsi_split));
- basic_block obb = gsi_bb (gsi_split);
- basic_block nbb = split_block (obb, gsi_stmt (gsi_split))->dest;
- gsi_next (&gsi_split);
- gcc_checking_assert (gsi_end_p (gsi_split));
-
- single_succ_edge (bb)->goto_locus = loc;
-
- if (dump_file)
- fprintf (dump_file,
- "Splitting block %i into %i"
- " before the conditional trap branch\n",
- obb->index, nbb->index);
- }
-
- /* If the check assignment must end a basic block, we can't
- insert the conditional branch in the same block, so split
- the block again, and prepare to insert the conditional
- branch in the new block.
-
- Also assign an EH region to the compare. Even though it's
- unlikely that the hardening compare will throw after the
- original compare didn't, the compiler won't even know that
- it's the same compare operands, so add the EH edge anyway. */
- if (throwing_compare_p)
- {
- add_stmt_to_eh_lp (asgnck, lookup_stmt_eh_lp (asgn));
- make_eh_edges (asgnck);
-
- edge ckeh;
- basic_block nbb = split_edge (non_eh_succ_edge
- (gimple_bb (asgnck), &ckeh));
- gsi_split = gsi_start_bb (nbb);
-
- if (dump_file)
- fprintf (dump_file,
- "Splitting non-EH edge from block %i into %i after"
- " the newly-inserted reversed throwing compare\n",
- gimple_bb (asgnck)->index, nbb->index);
-
- if (!gimple_seq_empty_p (phi_nodes (ckeh->dest)))
- {
- edge aseh;
- non_eh_succ_edge (gimple_bb (asgn), &aseh);
-
- gcc_checking_assert (aseh->dest == ckeh->dest);
-
- for (gphi_iterator psi = gsi_start_phis (ckeh->dest);
- !gsi_end_p (psi); gsi_next (&psi))
- {
- gphi *phi = psi.phi ();
- add_phi_arg (phi, PHI_ARG_DEF_FROM_EDGE (phi, aseh), ckeh,
- gimple_phi_arg_location_from_edge (phi, aseh));
- }
-
- if (dump_file)
- fprintf (dump_file,
- "Copying PHI args in EH block %i from %i to %i\n",
- aseh->dest->index, aseh->src->index, ckeh->src->index);
- }
- }
-
- gcc_checking_assert (single_succ_p (gsi_bb (gsi_split)));
-
- insert_check_and_trap (loc, &gsi_split, EDGE_TRUE_VALUE,
- EQ_EXPR, lhs, rhs);
- }
+
+ /* useless_type_conversion_p enables conversions from 1-bit
+ integer types to boolean to be discarded. */
+ gcc_checking_assert (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE
+ || (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
+ && TYPE_PRECISION (TREE_TYPE (lhs)) == 1));
+
+ tree rhs = copy_ssa_name (lhs);
+
+ gimple_stmt_iterator gsi_split = gsi;
+ /* Don't separate the original assignment from debug stmts
+ that might be associated with it, and arrange to split the
+ block after debug stmts, so as to make sure the split block
+ won't be debug stmts only. */
+ gsi_next_nondebug (&gsi_split);
+
+ bool throwing_compare_p = stmt_ends_bb_p (asgn);
+ if (throwing_compare_p)
+ {
+ basic_block nbb = split_edge (non_eh_succ_edge
+ (gimple_bb (asgn)));
+ gsi_split = gsi_start_bb (nbb);
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Splitting non-EH edge from block %i into %i"
+ " after a throwing compare\n",
+ gimple_bb (asgn)->index, nbb->index);
+ }
+
+ bool same_p = (op1 == op2);
+ op1 = detach_value (loc, &gsi_split, op1);
+ op2 = same_p ? op1 : detach_value (loc, &gsi_split, op2);
+
+ gassign *asgnck = gimple_build_assign (rhs, cop, op1, op2);
+ gimple_set_location (asgnck, loc);
+ gsi_insert_before (&gsi_split, asgnck, GSI_SAME_STMT);
+
+ /* We wish to insert a cond_expr after the compare, so arrange
+ for it to be at the end of a block if it isn't, and for it
+ to have a single successor in case there's more than
+ one, as in PR104975. */
+ if (!gsi_end_p (gsi_split)
+ || !single_succ_p (gsi_bb (gsi_split)))
+ {
+ if (!gsi_end_p (gsi_split))
+ gsi_prev (&gsi_split);
+ else
+ gsi_split = gsi_last_bb (gsi_bb (gsi_split));
+ basic_block obb = gsi_bb (gsi_split);
+ basic_block nbb = split_block (obb, gsi_stmt (gsi_split))->dest;
+ gsi_next (&gsi_split);
+ gcc_checking_assert (gsi_end_p (gsi_split));
+
+ single_succ_edge (bb)->goto_locus = loc;
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Splitting block %i into %i"
+ " before the conditional trap branch\n",
+ obb->index, nbb->index);
+ }
+
+ /* If the check assignment must end a basic block, we can't
+ insert the conditional branch in the same block, so split
+ the block again, and prepare to insert the conditional
+ branch in the new block.
+
+ Also assign an EH region to the compare. Even though it's
+ unlikely that the hardening compare will throw after the
+ original compare didn't, the compiler won't even know that
+ it's the same compare operands, so add the EH edge anyway. */
+ if (throwing_compare_p)
+ {
+ add_stmt_to_eh_lp (asgnck, lookup_stmt_eh_lp (asgn));
+ make_eh_edges (asgnck);
+
+ edge ckeh;
+ basic_block nbb = split_edge (non_eh_succ_edge
+ (gimple_bb (asgnck), &ckeh));
+ gsi_split = gsi_start_bb (nbb);
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Splitting non-EH edge from block %i into %i after"
+ " the newly-inserted reversed throwing compare\n",
+ gimple_bb (asgnck)->index, nbb->index);
+
+ if (!gimple_seq_empty_p (phi_nodes (ckeh->dest)))
+ {
+ edge aseh;
+ non_eh_succ_edge (gimple_bb (asgn), &aseh);
+
+ gcc_checking_assert (aseh->dest == ckeh->dest);
+
+ for (gphi_iterator psi = gsi_start_phis (ckeh->dest);
+ !gsi_end_p (psi); gsi_next (&psi))
+ {
+ gphi *phi = psi.phi ();
+ add_phi_arg (phi, PHI_ARG_DEF_FROM_EDGE (phi, aseh), ckeh,
+ gimple_phi_arg_location_from_edge (phi, aseh));
+ }
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Copying PHI args in EH block %i from %i to %i\n",
+ aseh->dest->index, aseh->src->index,
+ ckeh->src->index);
+ }
+ }
+
+ gcc_checking_assert (single_succ_p (gsi_bb (gsi_split)));
+
+ insert_check_and_trap (loc, &gsi_split, EDGE_TRUE_VALUE,
+ EQ_EXPR, lhs, rhs);
+ }
+ }
return 0;
}
^ permalink raw reply [flat|nested] 4+ messages in thread
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