| /* GIMPLE lowering pass. Converts High GIMPLE into Low GIMPLE. |
| |
| Copyright (C) 2003-2022 Free Software Foundation, Inc. |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify it under |
| the terms of the GNU General Public License as published by the Free |
| Software Foundation; either version 3, or (at your option) any later |
| version. |
| |
| GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "backend.h" |
| #include "tree.h" |
| #include "gimple.h" |
| #include "tree-pass.h" |
| #include "fold-const.h" |
| #include "tree-nested.h" |
| #include "calls.h" |
| #include "gimple-iterator.h" |
| #include "gimple-low.h" |
| #include "predict.h" |
| #include "gimple-predict.h" |
| #include "gimple-fold.h" |
| |
| /* The differences between High GIMPLE and Low GIMPLE are the |
| following: |
| |
| 1- Lexical scopes are removed (i.e., GIMPLE_BIND disappears). |
| |
| 2- GIMPLE_TRY and GIMPLE_CATCH are converted to abnormal control |
| flow and exception regions are built as an on-the-side region |
| hierarchy (See tree-eh.cc:lower_eh_constructs). |
| |
| 3- Multiple identical return statements are grouped into a single |
| return and gotos to the unique return site. */ |
| |
| /* Match a return statement with a label. During lowering, we identify |
| identical return statements and replace duplicates with a jump to |
| the corresponding label. */ |
| struct return_statements_t |
| { |
| tree label; |
| greturn *stmt; |
| }; |
| typedef struct return_statements_t return_statements_t; |
| |
| |
| struct lower_data |
| { |
| /* Block the current statement belongs to. */ |
| tree block; |
| |
| /* A vector of label and return statements to be moved to the end |
| of the function. */ |
| vec<return_statements_t> return_statements; |
| |
| /* True if the current statement cannot fall through. */ |
| bool cannot_fallthru; |
| }; |
| |
| static void lower_stmt (gimple_stmt_iterator *, struct lower_data *); |
| static void lower_gimple_bind (gimple_stmt_iterator *, struct lower_data *); |
| static void lower_try_catch (gimple_stmt_iterator *, struct lower_data *); |
| static void lower_gimple_return (gimple_stmt_iterator *, struct lower_data *); |
| static void lower_builtin_setjmp (gimple_stmt_iterator *); |
| static void lower_builtin_posix_memalign (gimple_stmt_iterator *); |
| |
| |
| /* Lower the body of current_function_decl from High GIMPLE into Low |
| GIMPLE. */ |
| |
| static unsigned int |
| lower_function_body (void) |
| { |
| struct lower_data data; |
| gimple_seq body = gimple_body (current_function_decl); |
| gimple_seq lowered_body; |
| gimple_stmt_iterator i; |
| gimple *bind; |
| gimple *x; |
| |
| /* The gimplifier should've left a body of exactly one statement, |
| namely a GIMPLE_BIND. */ |
| gcc_assert (gimple_seq_first (body) == gimple_seq_last (body) |
| && gimple_code (gimple_seq_first_stmt (body)) == GIMPLE_BIND); |
| |
| memset (&data, 0, sizeof (data)); |
| data.block = DECL_INITIAL (current_function_decl); |
| BLOCK_SUBBLOCKS (data.block) = NULL_TREE; |
| BLOCK_CHAIN (data.block) = NULL_TREE; |
| TREE_ASM_WRITTEN (data.block) = 1; |
| data.return_statements.create (8); |
| |
| bind = gimple_seq_first_stmt (body); |
| lowered_body = NULL; |
| gimple_seq_add_stmt (&lowered_body, bind); |
| i = gsi_start (lowered_body); |
| lower_gimple_bind (&i, &data); |
| |
| i = gsi_last (lowered_body); |
| |
| /* If we had begin stmt markers from e.g. PCH, but this compilation |
| doesn't want them, lower_stmt will have cleaned them up; we can |
| now clear the flag that indicates we had them. */ |
| if (!MAY_HAVE_DEBUG_MARKER_STMTS && cfun->debug_nonbind_markers) |
| { |
| /* This counter needs not be exact, but before lowering it will |
| most certainly be. */ |
| gcc_assert (cfun->debug_marker_count == 0); |
| cfun->debug_nonbind_markers = false; |
| } |
| |
| /* If the function falls off the end, we need a null return statement. |
| If we've already got one in the return_statements vector, we don't |
| need to do anything special. Otherwise build one by hand. */ |
| bool may_fallthru = gimple_seq_may_fallthru (lowered_body); |
| if (may_fallthru |
| && (data.return_statements.is_empty () |
| || (gimple_return_retval (data.return_statements.last().stmt) |
| != NULL))) |
| { |
| x = gimple_build_return (NULL); |
| gimple_set_location (x, cfun->function_end_locus); |
| gimple_set_block (x, DECL_INITIAL (current_function_decl)); |
| gsi_insert_after (&i, x, GSI_CONTINUE_LINKING); |
| may_fallthru = false; |
| } |
| |
| /* If we lowered any return statements, emit the representative |
| at the end of the function. */ |
| while (!data.return_statements.is_empty ()) |
| { |
| return_statements_t t = data.return_statements.pop (); |
| x = gimple_build_label (t.label); |
| gsi_insert_after (&i, x, GSI_CONTINUE_LINKING); |
| gsi_insert_after (&i, t.stmt, GSI_CONTINUE_LINKING); |
| if (may_fallthru) |
| { |
| /* Remove the line number from the representative return statement. |
| It now fills in for the fallthru too. Failure to remove this |
| will result in incorrect results for coverage analysis. */ |
| gimple_set_location (t.stmt, UNKNOWN_LOCATION); |
| may_fallthru = false; |
| } |
| } |
| |
| /* Once the old body has been lowered, replace it with the new |
| lowered sequence. */ |
| gimple_set_body (current_function_decl, lowered_body); |
| |
| gcc_assert (data.block == DECL_INITIAL (current_function_decl)); |
| BLOCK_SUBBLOCKS (data.block) |
| = blocks_nreverse (BLOCK_SUBBLOCKS (data.block)); |
| |
| clear_block_marks (data.block); |
| data.return_statements.release (); |
| return 0; |
| } |
| |
| namespace { |
| |
| const pass_data pass_data_lower_cf = |
| { |
| GIMPLE_PASS, /* type */ |
| "lower", /* name */ |
| OPTGROUP_NONE, /* optinfo_flags */ |
| TV_NONE, /* tv_id */ |
| PROP_gimple_any, /* properties_required */ |
| PROP_gimple_lcf, /* properties_provided */ |
| 0, /* properties_destroyed */ |
| 0, /* todo_flags_start */ |
| 0, /* todo_flags_finish */ |
| }; |
| |
| class pass_lower_cf : public gimple_opt_pass |
| { |
| public: |
| pass_lower_cf (gcc::context *ctxt) |
| : gimple_opt_pass (pass_data_lower_cf, ctxt) |
| {} |
| |
| /* opt_pass methods: */ |
| virtual unsigned int execute (function *) { return lower_function_body (); } |
| |
| }; // class pass_lower_cf |
| |
| } // anon namespace |
| |
| gimple_opt_pass * |
| make_pass_lower_cf (gcc::context *ctxt) |
| { |
| return new pass_lower_cf (ctxt); |
| } |
| |
| /* Lower sequence SEQ. Unlike gimplification the statements are not relowered |
| when they are changed -- if this has to be done, the lowering routine must |
| do it explicitly. DATA is passed through the recursion. */ |
| |
| static void |
| lower_sequence (gimple_seq *seq, struct lower_data *data) |
| { |
| gimple_stmt_iterator gsi; |
| |
| for (gsi = gsi_start (*seq); !gsi_end_p (gsi); ) |
| lower_stmt (&gsi, data); |
| } |
| |
| |
| /* Lower the OpenMP directive statement pointed by GSI. DATA is |
| passed through the recursion. */ |
| |
| static void |
| lower_omp_directive (gimple_stmt_iterator *gsi, struct lower_data *data) |
| { |
| gimple *stmt; |
| |
| stmt = gsi_stmt (*gsi); |
| |
| lower_sequence (gimple_omp_body_ptr (stmt), data); |
| gsi_insert_seq_after (gsi, gimple_omp_body (stmt), GSI_CONTINUE_LINKING); |
| gimple_omp_set_body (stmt, NULL); |
| gsi_next (gsi); |
| } |
| |
| |
| /* Lower statement GSI. DATA is passed through the recursion. We try to |
| track the fallthruness of statements and get rid of unreachable return |
| statements in order to prevent the EH lowering pass from adding useless |
| edges that can cause bogus warnings to be issued later; this guess need |
| not be 100% accurate, simply be conservative and reset cannot_fallthru |
| to false if we don't know. */ |
| |
| static void |
| lower_stmt (gimple_stmt_iterator *gsi, struct lower_data *data) |
| { |
| gimple *stmt = gsi_stmt (*gsi); |
| |
| gimple_set_block (stmt, data->block); |
| |
| switch (gimple_code (stmt)) |
| { |
| case GIMPLE_BIND: |
| lower_gimple_bind (gsi, data); |
| /* Propagate fallthruness. */ |
| return; |
| |
| case GIMPLE_COND: |
| case GIMPLE_GOTO: |
| case GIMPLE_SWITCH: |
| data->cannot_fallthru = true; |
| gsi_next (gsi); |
| return; |
| |
| case GIMPLE_RETURN: |
| if (data->cannot_fallthru) |
| { |
| gsi_remove (gsi, false); |
| /* Propagate fallthruness. */ |
| } |
| else |
| { |
| lower_gimple_return (gsi, data); |
| data->cannot_fallthru = true; |
| } |
| return; |
| |
| case GIMPLE_TRY: |
| if (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH) |
| lower_try_catch (gsi, data); |
| else |
| { |
| /* It must be a GIMPLE_TRY_FINALLY. */ |
| bool cannot_fallthru; |
| lower_sequence (gimple_try_eval_ptr (stmt), data); |
| cannot_fallthru = data->cannot_fallthru; |
| |
| /* The finally clause is always executed after the try clause, |
| so if it does not fall through, then the try-finally will not |
| fall through. Otherwise, if the try clause does not fall |
| through, then when the finally clause falls through it will |
| resume execution wherever the try clause was going. So the |
| whole try-finally will only fall through if both the try |
| clause and the finally clause fall through. */ |
| data->cannot_fallthru = false; |
| lower_sequence (gimple_try_cleanup_ptr (stmt), data); |
| data->cannot_fallthru |= cannot_fallthru; |
| gsi_next (gsi); |
| } |
| return; |
| |
| case GIMPLE_EH_ELSE: |
| { |
| geh_else *eh_else_stmt = as_a <geh_else *> (stmt); |
| lower_sequence (gimple_eh_else_n_body_ptr (eh_else_stmt), data); |
| lower_sequence (gimple_eh_else_e_body_ptr (eh_else_stmt), data); |
| } |
| break; |
| |
| case GIMPLE_DEBUG: |
| gcc_checking_assert (cfun->debug_nonbind_markers); |
| /* We can't possibly have debug bind stmts before lowering, we |
| first emit them when entering SSA. */ |
| gcc_checking_assert (gimple_debug_nonbind_marker_p (stmt)); |
| /* Propagate fallthruness. */ |
| /* If the function (e.g. from PCH) had debug stmts, but they're |
| disabled for this compilation, remove them. */ |
| if (!MAY_HAVE_DEBUG_MARKER_STMTS) |
| gsi_remove (gsi, true); |
| else |
| gsi_next (gsi); |
| return; |
| |
| case GIMPLE_NOP: |
| case GIMPLE_ASM: |
| case GIMPLE_ASSIGN: |
| case GIMPLE_PREDICT: |
| case GIMPLE_LABEL: |
| case GIMPLE_EH_MUST_NOT_THROW: |
| case GIMPLE_OMP_FOR: |
| case GIMPLE_OMP_SCOPE: |
| case GIMPLE_OMP_SECTIONS: |
| case GIMPLE_OMP_SECTIONS_SWITCH: |
| case GIMPLE_OMP_SECTION: |
| case GIMPLE_OMP_SINGLE: |
| case GIMPLE_OMP_MASTER: |
| case GIMPLE_OMP_MASKED: |
| case GIMPLE_OMP_TASKGROUP: |
| case GIMPLE_OMP_ORDERED: |
| case GIMPLE_OMP_SCAN: |
| case GIMPLE_OMP_CRITICAL: |
| case GIMPLE_OMP_RETURN: |
| case GIMPLE_OMP_ATOMIC_LOAD: |
| case GIMPLE_OMP_ATOMIC_STORE: |
| case GIMPLE_OMP_CONTINUE: |
| break; |
| |
| case GIMPLE_CALL: |
| { |
| tree decl = gimple_call_fndecl (stmt); |
| unsigned i; |
| |
| for (i = 0; i < gimple_call_num_args (stmt); i++) |
| { |
| tree arg = gimple_call_arg (stmt, i); |
| if (EXPR_P (arg)) |
| TREE_SET_BLOCK (arg, data->block); |
| } |
| |
| if (decl |
| && fndecl_built_in_p (decl, BUILT_IN_NORMAL)) |
| { |
| if (DECL_FUNCTION_CODE (decl) == BUILT_IN_SETJMP) |
| { |
| lower_builtin_setjmp (gsi); |
| data->cannot_fallthru = false; |
| return; |
| } |
| else if (DECL_FUNCTION_CODE (decl) == BUILT_IN_POSIX_MEMALIGN |
| && flag_tree_bit_ccp |
| && gimple_builtin_call_types_compatible_p (stmt, decl)) |
| { |
| lower_builtin_posix_memalign (gsi); |
| return; |
| } |
| } |
| |
| if (decl && (flags_from_decl_or_type (decl) & ECF_NORETURN)) |
| { |
| data->cannot_fallthru = true; |
| gsi_next (gsi); |
| return; |
| } |
| |
| /* We delay folding of built calls from gimplification to |
| here so the IL is in consistent state for the diagnostic |
| machineries job. */ |
| if (gimple_call_builtin_p (stmt)) |
| fold_stmt (gsi); |
| } |
| break; |
| |
| case GIMPLE_OMP_PARALLEL: |
| case GIMPLE_OMP_TASK: |
| case GIMPLE_OMP_TARGET: |
| case GIMPLE_OMP_TEAMS: |
| data->cannot_fallthru = false; |
| lower_omp_directive (gsi, data); |
| data->cannot_fallthru = false; |
| return; |
| |
| case GIMPLE_TRANSACTION: |
| lower_sequence (gimple_transaction_body_ptr ( |
| as_a <gtransaction *> (stmt)), |
| data); |
| break; |
| |
| default: |
| gcc_unreachable (); |
| } |
| |
| data->cannot_fallthru = false; |
| gsi_next (gsi); |
| } |
| |
| /* Lower a bind_expr TSI. DATA is passed through the recursion. */ |
| |
| static void |
| lower_gimple_bind (gimple_stmt_iterator *gsi, struct lower_data *data) |
| { |
| tree old_block = data->block; |
| gbind *stmt = as_a <gbind *> (gsi_stmt (*gsi)); |
| tree new_block = gimple_bind_block (stmt); |
| |
| if (new_block) |
| { |
| if (new_block == old_block) |
| { |
| /* The outermost block of the original function may not be the |
| outermost statement chain of the gimplified function. So we |
| may see the outermost block just inside the function. */ |
| gcc_assert (new_block == DECL_INITIAL (current_function_decl)); |
| new_block = NULL; |
| } |
| else |
| { |
| /* We do not expect to handle duplicate blocks. */ |
| gcc_assert (!TREE_ASM_WRITTEN (new_block)); |
| TREE_ASM_WRITTEN (new_block) = 1; |
| |
| /* Block tree may get clobbered by inlining. Normally this would |
| be fixed in rest_of_decl_compilation using block notes, but |
| since we are not going to emit them, it is up to us. */ |
| BLOCK_CHAIN (new_block) = BLOCK_SUBBLOCKS (old_block); |
| BLOCK_SUBBLOCKS (old_block) = new_block; |
| BLOCK_SUBBLOCKS (new_block) = NULL_TREE; |
| BLOCK_SUPERCONTEXT (new_block) = old_block; |
| |
| data->block = new_block; |
| } |
| } |
| |
| record_vars (gimple_bind_vars (stmt)); |
| |
| /* Scrap DECL_CHAIN up to BLOCK_VARS to ease GC after we no longer |
| need gimple_bind_vars. */ |
| tree next; |
| /* BLOCK_VARS and gimple_bind_vars share a common sub-chain. Find |
| it by marking all BLOCK_VARS. */ |
| if (gimple_bind_block (stmt)) |
| for (tree t = BLOCK_VARS (gimple_bind_block (stmt)); t; t = DECL_CHAIN (t)) |
| TREE_VISITED (t) = 1; |
| for (tree var = gimple_bind_vars (stmt); |
| var && ! TREE_VISITED (var); var = next) |
| { |
| next = DECL_CHAIN (var); |
| DECL_CHAIN (var) = NULL_TREE; |
| } |
| /* Unmark BLOCK_VARS. */ |
| if (gimple_bind_block (stmt)) |
| for (tree t = BLOCK_VARS (gimple_bind_block (stmt)); t; t = DECL_CHAIN (t)) |
| TREE_VISITED (t) = 0; |
| |
| lower_sequence (gimple_bind_body_ptr (stmt), data); |
| |
| if (new_block) |
| { |
| gcc_assert (data->block == new_block); |
| |
| BLOCK_SUBBLOCKS (new_block) |
| = blocks_nreverse (BLOCK_SUBBLOCKS (new_block)); |
| data->block = old_block; |
| } |
| |
| /* The GIMPLE_BIND no longer carries any useful information -- kill it. */ |
| gsi_insert_seq_before (gsi, gimple_bind_body (stmt), GSI_SAME_STMT); |
| gsi_remove (gsi, false); |
| } |
| |
| /* Same as above, but for a GIMPLE_TRY_CATCH. */ |
| |
| static void |
| lower_try_catch (gimple_stmt_iterator *gsi, struct lower_data *data) |
| { |
| bool cannot_fallthru; |
| gimple *stmt = gsi_stmt (*gsi); |
| gimple_stmt_iterator i; |
| |
| /* We don't handle GIMPLE_TRY_FINALLY. */ |
| gcc_assert (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH); |
| |
| lower_sequence (gimple_try_eval_ptr (stmt), data); |
| cannot_fallthru = data->cannot_fallthru; |
| |
| i = gsi_start (*gimple_try_cleanup_ptr (stmt)); |
| switch (gimple_code (gsi_stmt (i))) |
| { |
| case GIMPLE_CATCH: |
| /* We expect to see a sequence of GIMPLE_CATCH stmts, each with a |
| catch expression and a body. The whole try/catch may fall |
| through iff any of the catch bodies falls through. */ |
| for (; !gsi_end_p (i); gsi_next (&i)) |
| { |
| data->cannot_fallthru = false; |
| lower_sequence (gimple_catch_handler_ptr ( |
| as_a <gcatch *> (gsi_stmt (i))), |
| data); |
| if (!data->cannot_fallthru) |
| cannot_fallthru = false; |
| } |
| break; |
| |
| case GIMPLE_EH_FILTER: |
| /* The exception filter expression only matters if there is an |
| exception. If the exception does not match EH_FILTER_TYPES, |
| we will execute EH_FILTER_FAILURE, and we will fall through |
| if that falls through. If the exception does match |
| EH_FILTER_TYPES, the stack unwinder will continue up the |
| stack, so we will not fall through. We don't know whether we |
| will throw an exception which matches EH_FILTER_TYPES or not, |
| so we just ignore EH_FILTER_TYPES and assume that we might |
| throw an exception which doesn't match. */ |
| data->cannot_fallthru = false; |
| lower_sequence (gimple_eh_filter_failure_ptr (gsi_stmt (i)), data); |
| if (!data->cannot_fallthru) |
| cannot_fallthru = false; |
| break; |
| |
| case GIMPLE_DEBUG: |
| gcc_checking_assert (gimple_debug_begin_stmt_p (stmt)); |
| break; |
| |
| default: |
| /* This case represents statements to be executed when an |
| exception occurs. Those statements are implicitly followed |
| by a GIMPLE_RESX to resume execution after the exception. So |
| in this case the try/catch never falls through. */ |
| data->cannot_fallthru = false; |
| lower_sequence (gimple_try_cleanup_ptr (stmt), data); |
| break; |
| } |
| |
| data->cannot_fallthru = cannot_fallthru; |
| gsi_next (gsi); |
| } |
| |
| |
| /* Try to determine whether a TRY_CATCH expression can fall through. |
| This is a subroutine of gimple_stmt_may_fallthru. */ |
| |
| static bool |
| gimple_try_catch_may_fallthru (gtry *stmt) |
| { |
| gimple_stmt_iterator i; |
| |
| /* We don't handle GIMPLE_TRY_FINALLY. */ |
| gcc_assert (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH); |
| |
| /* If the TRY block can fall through, the whole TRY_CATCH can |
| fall through. */ |
| if (gimple_seq_may_fallthru (gimple_try_eval (stmt))) |
| return true; |
| |
| i = gsi_start (*gimple_try_cleanup_ptr (stmt)); |
| switch (gimple_code (gsi_stmt (i))) |
| { |
| case GIMPLE_CATCH: |
| /* We expect to see a sequence of GIMPLE_CATCH stmts, each with a |
| catch expression and a body. The whole try/catch may fall |
| through iff any of the catch bodies falls through. */ |
| for (; !gsi_end_p (i); gsi_next (&i)) |
| { |
| if (gimple_seq_may_fallthru (gimple_catch_handler ( |
| as_a <gcatch *> (gsi_stmt (i))))) |
| return true; |
| } |
| return false; |
| |
| case GIMPLE_EH_FILTER: |
| /* The exception filter expression only matters if there is an |
| exception. If the exception does not match EH_FILTER_TYPES, |
| we will execute EH_FILTER_FAILURE, and we will fall through |
| if that falls through. If the exception does match |
| EH_FILTER_TYPES, the stack unwinder will continue up the |
| stack, so we will not fall through. We don't know whether we |
| will throw an exception which matches EH_FILTER_TYPES or not, |
| so we just ignore EH_FILTER_TYPES and assume that we might |
| throw an exception which doesn't match. */ |
| return gimple_seq_may_fallthru (gimple_eh_filter_failure (gsi_stmt (i))); |
| |
| default: |
| /* This case represents statements to be executed when an |
| exception occurs. Those statements are implicitly followed |
| by a GIMPLE_RESX to resume execution after the exception. So |
| in this case the try/catch never falls through. */ |
| return false; |
| } |
| } |
| |
| |
| /* Try to determine if we can continue executing the statement |
| immediately following STMT. This guess need not be 100% accurate; |
| simply be conservative and return true if we don't know. This is |
| used only to avoid stupidly generating extra code. If we're wrong, |
| we'll just delete the extra code later. */ |
| |
| bool |
| gimple_stmt_may_fallthru (gimple *stmt) |
| { |
| if (!stmt) |
| return true; |
| |
| switch (gimple_code (stmt)) |
| { |
| case GIMPLE_GOTO: |
| case GIMPLE_RETURN: |
| case GIMPLE_RESX: |
| /* Easy cases. If the last statement of the seq implies |
| control transfer, then we can't fall through. */ |
| return false; |
| |
| case GIMPLE_SWITCH: |
| /* Switch has already been lowered and represents a branch |
| to a selected label and hence can't fall through. */ |
| return false; |
| |
| case GIMPLE_COND: |
| /* GIMPLE_COND's are already lowered into a two-way branch. They |
| can't fall through. */ |
| return false; |
| |
| case GIMPLE_BIND: |
| return gimple_seq_may_fallthru ( |
| gimple_bind_body (as_a <gbind *> (stmt))); |
| |
| case GIMPLE_TRY: |
| if (gimple_try_kind (stmt) == GIMPLE_TRY_CATCH) |
| return gimple_try_catch_may_fallthru (as_a <gtry *> (stmt)); |
| |
| /* It must be a GIMPLE_TRY_FINALLY. */ |
| |
| /* The finally clause is always executed after the try clause, |
| so if it does not fall through, then the try-finally will not |
| fall through. Otherwise, if the try clause does not fall |
| through, then when the finally clause falls through it will |
| resume execution wherever the try clause was going. So the |
| whole try-finally will only fall through if both the try |
| clause and the finally clause fall through. */ |
| return (gimple_seq_may_fallthru (gimple_try_eval (stmt)) |
| && gimple_seq_may_fallthru (gimple_try_cleanup (stmt))); |
| |
| case GIMPLE_EH_ELSE: |
| { |
| geh_else *eh_else_stmt = as_a <geh_else *> (stmt); |
| return (gimple_seq_may_fallthru (gimple_eh_else_n_body (eh_else_stmt)) |
| || gimple_seq_may_fallthru (gimple_eh_else_e_body ( |
| eh_else_stmt))); |
| } |
| |
| case GIMPLE_CALL: |
| /* Functions that do not return do not fall through. */ |
| return !gimple_call_noreturn_p (stmt); |
| |
| default: |
| return true; |
| } |
| } |
| |
| |
| /* Same as gimple_stmt_may_fallthru, but for the gimple sequence SEQ. */ |
| |
| bool |
| gimple_seq_may_fallthru (gimple_seq seq) |
| { |
| return gimple_stmt_may_fallthru (gimple_seq_last_nondebug_stmt (seq)); |
| } |
| |
| |
| /* Lower a GIMPLE_RETURN GSI. DATA is passed through the recursion. */ |
| |
| static void |
| lower_gimple_return (gimple_stmt_iterator *gsi, struct lower_data *data) |
| { |
| greturn *stmt = as_a <greturn *> (gsi_stmt (*gsi)); |
| gimple *t; |
| int i; |
| return_statements_t tmp_rs; |
| |
| /* Match this up with an existing return statement that's been created. */ |
| for (i = data->return_statements.length () - 1; |
| i >= 0; i--) |
| { |
| tmp_rs = data->return_statements[i]; |
| |
| if (gimple_return_retval (stmt) == gimple_return_retval (tmp_rs.stmt)) |
| { |
| /* Remove the line number from the representative return statement. |
| It now fills in for many such returns. Failure to remove this |
| will result in incorrect results for coverage analysis. */ |
| gimple_set_location (tmp_rs.stmt, UNKNOWN_LOCATION); |
| |
| goto found; |
| } |
| } |
| |
| /* Not found. Create a new label and record the return statement. */ |
| tmp_rs.label = create_artificial_label (cfun->function_end_locus); |
| tmp_rs.stmt = stmt; |
| data->return_statements.safe_push (tmp_rs); |
| |
| /* Generate a goto statement and remove the return statement. */ |
| found: |
| /* When not optimizing, make sure user returns are preserved. */ |
| if (!optimize && gimple_has_location (stmt)) |
| DECL_ARTIFICIAL (tmp_rs.label) = 0; |
| t = gimple_build_goto (tmp_rs.label); |
| /* location includes block. */ |
| gimple_set_location (t, gimple_location (stmt)); |
| gsi_insert_before (gsi, t, GSI_SAME_STMT); |
| gsi_remove (gsi, false); |
| } |
| |
| /* Lower a __builtin_setjmp GSI. |
| |
| __builtin_setjmp is passed a pointer to an array of five words (not |
| all will be used on all machines). It operates similarly to the C |
| library function of the same name, but is more efficient. |
| |
| It is lowered into 2 other builtins, namely __builtin_setjmp_setup, |
| __builtin_setjmp_receiver. |
| |
| After full lowering, the body of the function should look like: |
| |
| { |
| int D.1844; |
| int D.2844; |
| |
| [...] |
| |
| __builtin_setjmp_setup (&buf, &<D1847>); |
| D.1844 = 0; |
| goto <D1846>; |
| <D1847>:; |
| __builtin_setjmp_receiver (&<D1847>); |
| D.1844 = 1; |
| <D1846>:; |
| if (D.1844 == 0) goto <D1848>; else goto <D1849>; |
| |
| [...] |
| |
| __builtin_setjmp_setup (&buf, &<D2847>); |
| D.2844 = 0; |
| goto <D2846>; |
| <D2847>:; |
| __builtin_setjmp_receiver (&<D2847>); |
| D.2844 = 1; |
| <D2846>:; |
| if (D.2844 == 0) goto <D2848>; else goto <D2849>; |
| |
| [...] |
| |
| <D3850>:; |
| return; |
| } |
| |
| During cfg creation an extra per-function (or per-OpenMP region) |
| block with ABNORMAL_DISPATCHER internal call will be added, unique |
| destination of all the abnormal call edges and the unique source of |
| all the abnormal edges to the receivers, thus keeping the complexity |
| explosion localized. */ |
| |
| static void |
| lower_builtin_setjmp (gimple_stmt_iterator *gsi) |
| { |
| gimple *stmt = gsi_stmt (*gsi); |
| location_t loc = gimple_location (stmt); |
| tree cont_label = create_artificial_label (loc); |
| tree next_label = create_artificial_label (loc); |
| tree dest, t, arg; |
| gimple *g; |
| |
| /* __builtin_setjmp_{setup,receiver} aren't ECF_RETURNS_TWICE and for RTL |
| these builtins are modelled as non-local label jumps to the label |
| that is passed to these two builtins, so pretend we have a non-local |
| label during GIMPLE passes too. See PR60003. */ |
| cfun->has_nonlocal_label = 1; |
| |
| /* NEXT_LABEL is the label __builtin_longjmp will jump to. Its address is |
| passed to both __builtin_setjmp_setup and __builtin_setjmp_receiver. */ |
| FORCED_LABEL (next_label) = 1; |
| |
| tree orig_dest = dest = gimple_call_lhs (stmt); |
| if (orig_dest && TREE_CODE (orig_dest) == SSA_NAME) |
| dest = create_tmp_reg (TREE_TYPE (orig_dest)); |
| |
| /* Build '__builtin_setjmp_setup (BUF, NEXT_LABEL)' and insert. */ |
| arg = build_addr (next_label); |
| t = builtin_decl_implicit (BUILT_IN_SETJMP_SETUP); |
| g = gimple_build_call (t, 2, gimple_call_arg (stmt, 0), arg); |
| /* location includes block. */ |
| gimple_set_location (g, loc); |
| gsi_insert_before (gsi, g, GSI_SAME_STMT); |
| |
| /* Build 'DEST = 0' and insert. */ |
| if (dest) |
| { |
| g = gimple_build_assign (dest, build_zero_cst (TREE_TYPE (dest))); |
| gimple_set_location (g, loc); |
| gsi_insert_before (gsi, g, GSI_SAME_STMT); |
| } |
| |
| /* Build 'goto CONT_LABEL' and insert. */ |
| g = gimple_build_goto (cont_label); |
| gsi_insert_before (gsi, g, GSI_SAME_STMT); |
| |
| /* Build 'NEXT_LABEL:' and insert. */ |
| g = gimple_build_label (next_label); |
| gsi_insert_before (gsi, g, GSI_SAME_STMT); |
| |
| /* Build '__builtin_setjmp_receiver (NEXT_LABEL)' and insert. */ |
| arg = build_addr (next_label); |
| t = builtin_decl_implicit (BUILT_IN_SETJMP_RECEIVER); |
| g = gimple_build_call (t, 1, arg); |
| gimple_set_location (g, loc); |
| gsi_insert_before (gsi, g, GSI_SAME_STMT); |
| |
| /* Build 'DEST = 1' and insert. */ |
| if (dest) |
| { |
| g = gimple_build_assign (dest, fold_convert_loc (loc, TREE_TYPE (dest), |
| integer_one_node)); |
| gimple_set_location (g, loc); |
| gsi_insert_before (gsi, g, GSI_SAME_STMT); |
| } |
| |
| /* Build 'CONT_LABEL:' and insert. */ |
| g = gimple_build_label (cont_label); |
| gsi_insert_before (gsi, g, GSI_SAME_STMT); |
| |
| /* Build orig_dest = dest if necessary. */ |
| if (dest != orig_dest) |
| { |
| g = gimple_build_assign (orig_dest, dest); |
| gsi_insert_before (gsi, g, GSI_SAME_STMT); |
| } |
| |
| /* Remove the call to __builtin_setjmp. */ |
| gsi_remove (gsi, false); |
| } |
| |
| /* Lower calls to posix_memalign to |
| res = posix_memalign (ptr, align, size); |
| if (res == 0) |
| *ptr = __builtin_assume_aligned (*ptr, align); |
| or to |
| void *tem; |
| res = posix_memalign (&tem, align, size); |
| if (res == 0) |
| ptr = __builtin_assume_aligned (tem, align); |
| in case the first argument was &ptr. That way we can get at the |
| alignment of the heap pointer in CCP. */ |
| |
| static void |
| lower_builtin_posix_memalign (gimple_stmt_iterator *gsi) |
| { |
| gimple *stmt, *call = gsi_stmt (*gsi); |
| tree pptr = gimple_call_arg (call, 0); |
| tree align = gimple_call_arg (call, 1); |
| tree res = gimple_call_lhs (call); |
| tree ptr = create_tmp_reg (ptr_type_node); |
| if (TREE_CODE (pptr) == ADDR_EXPR) |
| { |
| tree tem = create_tmp_var (ptr_type_node); |
| TREE_ADDRESSABLE (tem) = 1; |
| gimple_call_set_arg (call, 0, build_fold_addr_expr (tem)); |
| stmt = gimple_build_assign (ptr, tem); |
| } |
| else |
| stmt = gimple_build_assign (ptr, |
| fold_build2 (MEM_REF, ptr_type_node, pptr, |
| build_int_cst (ptr_type_node, 0))); |
| if (res == NULL_TREE) |
| { |
| res = create_tmp_reg (integer_type_node); |
| gimple_call_set_lhs (call, res); |
| } |
| tree align_label = create_artificial_label (UNKNOWN_LOCATION); |
| tree noalign_label = create_artificial_label (UNKNOWN_LOCATION); |
| gimple *cond = gimple_build_cond (EQ_EXPR, res, integer_zero_node, |
| align_label, noalign_label); |
| gsi_insert_after (gsi, cond, GSI_NEW_STMT); |
| gsi_insert_after (gsi, gimple_build_label (align_label), GSI_NEW_STMT); |
| gsi_insert_after (gsi, stmt, GSI_NEW_STMT); |
| stmt = gimple_build_call (builtin_decl_implicit (BUILT_IN_ASSUME_ALIGNED), |
| 2, ptr, align); |
| gimple_call_set_lhs (stmt, ptr); |
| gsi_insert_after (gsi, stmt, GSI_NEW_STMT); |
| stmt = gimple_build_assign (fold_build2 (MEM_REF, ptr_type_node, pptr, |
| build_int_cst (ptr_type_node, 0)), |
| ptr); |
| gsi_insert_after (gsi, stmt, GSI_NEW_STMT); |
| gsi_insert_after (gsi, gimple_build_label (noalign_label), GSI_NEW_STMT); |
| } |
| |
| |
| /* Record the variables in VARS into function FN. */ |
| |
| void |
| record_vars_into (tree vars, tree fn) |
| { |
| for (; vars; vars = DECL_CHAIN (vars)) |
| { |
| tree var = vars; |
| |
| /* BIND_EXPRs contains also function/type/constant declarations |
| we don't need to care about. */ |
| if (!VAR_P (var)) |
| continue; |
| |
| /* Nothing to do in this case. */ |
| if (DECL_EXTERNAL (var)) |
| continue; |
| |
| /* Record the variable. */ |
| add_local_decl (DECL_STRUCT_FUNCTION (fn), var); |
| } |
| } |
| |
| |
| /* Record the variables in VARS into current_function_decl. */ |
| |
| void |
| record_vars (tree vars) |
| { |
| record_vars_into (vars, current_function_decl); |
| } |