diff options
Diffstat (limited to 'gcc/tree-into-ssa.c')
| -rw-r--r-- | gcc/tree-into-ssa.c | 106 |
1 files changed, 99 insertions, 7 deletions
diff --git a/gcc/tree-into-ssa.c b/gcc/tree-into-ssa.c index bdec080..9f06e8c 100644 --- a/gcc/tree-into-ssa.c +++ b/gcc/tree-into-ssa.c @@ -749,6 +749,9 @@ mark_def_sites (basic_block bb, gimple stmt, bitmap kills) set_register_defs (stmt, false); set_rewrite_uses (stmt, false); + if (is_gimple_debug (stmt)) + return; + /* If a variable is used before being set, then the variable is live across a block boundary, so mark it live-on-entry to BB. */ FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) @@ -1051,7 +1054,6 @@ mark_phi_for_rewrite (basic_block bb, gimple phi) VEC_replace (gimple_vec, phis_to_rewrite, idx, phis); } - /* Insert PHI nodes for variable VAR using the iterated dominance frontier given in PHI_INSERTION_POINTS. If UPDATE_P is true, this function assumes that the caller is incrementally updating the @@ -1118,8 +1120,17 @@ insert_phi_nodes_for (tree var, bitmap phi_insertion_points, bool update_p) } else { + tree tracked_var; gcc_assert (DECL_P (var)); phi = create_phi_node (var, bb); + if (!update_p && (tracked_var = target_for_debug_bind (var))) + { + gimple note = gimple_build_debug_bind (tracked_var, + PHI_RESULT (phi), + phi); + gimple_stmt_iterator si = gsi_after_labels (bb); + gsi_insert_before (&si, note, GSI_SAME_STMT); + } } /* Mark this PHI node as interesting for update_ssa. */ @@ -1260,11 +1271,12 @@ get_reaching_def (tree var) definition of a variable when a new real or virtual definition is found. */ static void -rewrite_stmt (gimple stmt) +rewrite_stmt (gimple_stmt_iterator si) { use_operand_p use_p; def_operand_p def_p; ssa_op_iter iter; + gimple stmt = gsi_stmt (si); /* If mark_def_sites decided that we don't need to rewrite this statement, ignore it. */ @@ -1293,9 +1305,18 @@ rewrite_stmt (gimple stmt) FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF) { tree var = DEF_FROM_PTR (def_p); + tree name = make_ssa_name (var, stmt); + tree tracked_var; gcc_assert (DECL_P (var)); - SET_DEF (def_p, make_ssa_name (var, stmt)); + SET_DEF (def_p, name); register_new_def (DEF_FROM_PTR (def_p), var); + + tracked_var = target_for_debug_bind (var); + if (tracked_var) + { + gimple note = gimple_build_debug_bind (tracked_var, name, stmt); + gsi_insert_after (&si, note, GSI_SAME_STMT); + } } } @@ -1366,7 +1387,7 @@ rewrite_enter_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, of a variable when a new real or virtual definition is found. */ if (TEST_BIT (interesting_blocks, bb->index)) for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) - rewrite_stmt (gsi_stmt (gsi)); + rewrite_stmt (gsi); /* Step 3. Visit all the successor blocks of BB looking for PHI nodes. For every PHI node found, add a new argument containing the current @@ -1759,6 +1780,38 @@ maybe_replace_use (use_operand_p use_p) } +/* Same as maybe_replace_use, but without introducing default stmts, + returning false to indicate a need to do so. */ + +static inline bool +maybe_replace_use_in_debug_stmt (use_operand_p use_p) +{ + tree rdef = NULL_TREE; + tree use = USE_FROM_PTR (use_p); + tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); + + if (symbol_marked_for_renaming (sym)) + rdef = get_current_def (sym); + else if (is_old_name (use)) + { + rdef = get_current_def (use); + /* We can't assume that, if there's no current definition, the + default one should be used. It could be the case that we've + rearranged blocks so that the earlier definition no longer + dominates the use. */ + if (!rdef && SSA_NAME_IS_DEFAULT_DEF (use)) + rdef = use; + } + else + rdef = use; + + if (rdef && rdef != use) + SET_USE (use_p, rdef); + + return rdef != NULL_TREE; +} + + /* 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 @@ -1825,8 +1878,42 @@ rewrite_update_stmt (gimple stmt) /* Rewrite USES included in OLD_SSA_NAMES and USES whose underlying symbol is marked for renaming. */ if (rewrite_uses_p (stmt)) - FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) - maybe_replace_use (use_p); + { + if (is_gimple_debug (stmt)) + { + bool failed = false; + + FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) + if (!maybe_replace_use_in_debug_stmt (use_p)) + { + failed = true; + break; + } + + if (failed) + { + /* DOM sometimes threads jumps in such a way that a + debug stmt ends up referencing a SSA variable that no + longer dominates the debug stmt, but such that all + incoming definitions refer to the same definition in + an earlier dominator. We could try to recover that + definition somehow, but this will have to do for now. + + Introducing a default definition, which is what + maybe_replace_use() would do in such cases, may + modify code generation, for the otherwise-unused + default definition would never go away, modifying SSA + version numbers all over. */ + gimple_debug_bind_reset_value (stmt); + update_stmt (stmt); + } + } + else + { + FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) + maybe_replace_use (use_p); + } + } /* Register definitions of names in NEW_SSA_NAMES and OLD_SSA_NAMES. Also register definitions for names whose underlying symbol is @@ -2325,7 +2412,12 @@ mark_use_interesting (tree var, gimple stmt, basic_block bb, bool insert_phi_p) if (gimple_code (stmt) == GIMPLE_PHI) mark_phi_for_rewrite (def_bb, stmt); else - set_rewrite_uses (stmt, true); + { + set_rewrite_uses (stmt, true); + + if (is_gimple_debug (stmt)) + return; + } /* If VAR has not been defined in BB, then it is live-on-entry to BB. Note that we cannot just use the block holding VAR's |