| Message ID | 20200402074805.GN2212@tucnak |
|---|---|
| State | New |
| Headers | show |
| Series | c++: Fix further protected_set_expr_location related -fcompare-debug issues [PR94441] | expand |
On 4/2/20 3:48 AM, Jakub Jelinek wrote: > Hi! > > My recent protected_set_expr_location changes work well when > that function is called unconditionally, but as the testcase shows, the C++ > FE has a few spots that do: > if (!EXPR_HAS_LOCATION (stmt)) > protected_set_expr_location (stmt, locus); > or similar. Now, if we have for -g0 stmt of some expression that can > have location and has != UNKNOWN_LOCATION, while -g instead has > a STATEMENT_LIST containing some DEBUG_BEGIN_STMTs + that expression with > that location, we don't call protected_set_expr_location in the -g0 case, > but do call it in the -g case, because on the STATEMENT_LIST > !EXPR_HAS_LOCATION. > The following patch introduces a helper function which digs up the single > expression of a STATEMENT_LIST and uses that expression in the > EXPR_HAS_LOCATION check (plus changes protected_set_expr_location to > also use that helper). > > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? > > Or do we want a further wrapper, perhaps C++ FE only, that would do this > protected_set_expr_location_if_unset (stmt, locus)? That sounds good to me. > 2020-04-02 Jakub Jelinek <jakub@redhat.com> > > PR debug/94441 > * tree-iterator.h (expr_single): Declare. > * tree-iterator.c (expr_single): New function. > * tree.c (protected_set_expr_location): Use it. > > * parser.c (cp_parser_omp_for_loop): Use expr_single. > * cp-gimplify.c (genericize_if_stmt, genericize_cp_loop): Likewise. > > * g++.dg/opt/pr94441.C: New test. > > --- gcc/tree-iterator.h.jj 2020-01-12 11:54:38.497381967 +0100 > +++ gcc/tree-iterator.h 2020-04-01 16:58:00.034347283 +0200 > @@ -119,5 +119,6 @@ extern void append_to_statement_list (tr > extern void append_to_statement_list_force (tree, tree *); > extern tree expr_first (tree); > extern tree expr_last (tree); > +extern tree expr_single (tree); > > #endif /* GCC_TREE_ITERATOR_H */ > --- gcc/tree-iterator.c.jj 2020-01-12 11:54:38.497381967 +0100 > +++ gcc/tree-iterator.c 2020-04-01 17:05:23.388920122 +0200 > @@ -354,4 +354,45 @@ expr_last (tree expr) > return expr; > } > > +/* If EXPR is a STATEMENT_LIST containing just DEBUG_BEGIN_STMTs and > + a single other stmt, return that other stmt (recursively). > + If it is a STATEMENT_LIST containing no non-DEBUG_BEGIN_STMTs or > + multiple, return NULL_TREE. > + Otherwise return EXPR. */ > + > +tree > +expr_single (tree expr) > +{ > + if (expr == NULL_TREE) > + return expr; > + > + if (TREE_CODE (expr) == STATEMENT_LIST) > + { > + /* With -gstatement-frontiers we could have a STATEMENT_LIST with > + DEBUG_BEGIN_STMT(s) and only a single other stmt, which with > + -g wouldn't be present and we'd have that single other stmt > + directly instead. */ > + struct tree_statement_list_node *n = STATEMENT_LIST_HEAD (expr); > + if (!n) > + return NULL_TREE; > + while (TREE_CODE (n->stmt) == DEBUG_BEGIN_STMT) > + { > + n = n->next; > + if (!n) > + return NULL_TREE; > + } > + expr = n->stmt; > + do > + { > + n = n->next; > + if (!n) > + return expr_single (expr); > + } > + while (TREE_CODE (n->stmt) == DEBUG_BEGIN_STMT); > + return NULL_TREE; > + } > + > + return expr; > +} > + > #include "gt-tree-iterator.h" > --- gcc/tree.c.jj 2020-03-26 10:35:29.984667559 +0100 > +++ gcc/tree.c 2020-04-01 16:59:01.689453490 +0200 > @@ -5148,30 +5148,9 @@ protected_set_expr_location (tree t, loc > SET_EXPR_LOCATION (t, loc); > else if (t && TREE_CODE (t) == STATEMENT_LIST) > { > - /* With -gstatement-frontiers we could have a STATEMENT_LIST with > - DEBUG_BEGIN_STMT(s) and only a single other stmt, which with > - -g wouldn't be present and we'd have that single other stmt > - directly instead. */ > - struct tree_statement_list_node *n = STATEMENT_LIST_HEAD (t); > - if (!n) > - return; > - while (TREE_CODE (n->stmt) == DEBUG_BEGIN_STMT) > - { > - n = n->next; > - if (!n) > - return; > - } > - tree t2 = n->stmt; > - do > - { > - n = n->next; > - if (!n) > - { > - protected_set_expr_location (t2, loc); > - return; > - } > - } > - while (TREE_CODE (n->stmt) == DEBUG_BEGIN_STMT); > + t = expr_single (t); > + if (t && CAN_HAVE_LOCATION_P (t)) > + SET_EXPR_LOCATION (t, loc); > } > } > > --- gcc/cp/parser.c.jj 2020-03-29 11:14:41.087556278 +0200 > +++ gcc/cp/parser.c 2020-04-01 17:03:00.730988186 +0200 > @@ -39149,8 +39149,9 @@ cp_parser_omp_for_loop (cp_parser *parse > incr = cp_parser_omp_for_incr (parser, real_decl); > else > incr = cp_parser_expression (parser); > - if (!EXPR_HAS_LOCATION (incr)) > - protected_set_expr_location (incr, input_location); > + if (tree incrl = expr_single (incr)) > + if (!EXPR_HAS_LOCATION (incrl)) > + protected_set_expr_location (incrl, input_location); > } > > parse_close_paren: > --- gcc/cp/cp-gimplify.c.jj 2020-03-29 11:14:41.057556738 +0200 > +++ gcc/cp/cp-gimplify.c 2020-04-01 17:01:28.916319192 +0200 > @@ -226,8 +226,9 @@ genericize_if_stmt (tree *stmt_p) > stmt = else_; > else > stmt = build3 (COND_EXPR, void_type_node, cond, then_, else_); > - if (!EXPR_HAS_LOCATION (stmt)) > - protected_set_expr_location (stmt, locus); > + if (tree stmtl = expr_single (stmt)) > + if (!EXPR_HAS_LOCATION (stmtl)) > + protected_set_expr_location (stmtl, locus); > *stmt_p = stmt; > } > > @@ -248,8 +249,9 @@ genericize_cp_loop (tree *stmt_p, locati > tree stmt_list = NULL; > tree debug_begin = NULL; > > - if (EXPR_LOCATION (incr) == UNKNOWN_LOCATION) > - protected_set_expr_location (incr, start_locus); > + if (tree incrl = expr_single (incr)) > + if (!EXPR_HAS_LOCATION (incrl)) > + protected_set_expr_location (incrl, start_locus); > > cp_walk_tree (&cond, cp_genericize_r, data, NULL); > cp_walk_tree (&incr, cp_genericize_r, data, NULL); > --- gcc/testsuite/g++.dg/opt/pr94441.C.jj 2020-04-01 17:13:43.014677438 +0200 > +++ gcc/testsuite/g++.dg/opt/pr94441.C 2020-04-01 17:14:33.495946020 +0200 > @@ -0,0 +1,16 @@ > +// PR debug/94441 > +// { dg-do compile } > +// { dg-options "-O3 -fno-forward-propagate --param=max-cse-insns=0 -flive-range-shrinkage -std=c++17 -fcompare-debug" } > + > +template <class,class> struct Same; > +template <class T> struct Same<T,T> {}; > + > +auto f() > +{ > + if constexpr (sizeof(int)==3) > + return 42; > + else > + return 42L; > +} > + > +Same<decltype(f()), long> s; > > Jakub >
--- gcc/tree-iterator.h.jj 2020-01-12 11:54:38.497381967 +0100 +++ gcc/tree-iterator.h 2020-04-01 16:58:00.034347283 +0200 @@ -119,5 +119,6 @@ extern void append_to_statement_list (tr extern void append_to_statement_list_force (tree, tree *); extern tree expr_first (tree); extern tree expr_last (tree); +extern tree expr_single (tree); #endif /* GCC_TREE_ITERATOR_H */ --- gcc/tree-iterator.c.jj 2020-01-12 11:54:38.497381967 +0100 +++ gcc/tree-iterator.c 2020-04-01 17:05:23.388920122 +0200 @@ -354,4 +354,45 @@ expr_last (tree expr) return expr; } +/* If EXPR is a STATEMENT_LIST containing just DEBUG_BEGIN_STMTs and + a single other stmt, return that other stmt (recursively). + If it is a STATEMENT_LIST containing no non-DEBUG_BEGIN_STMTs or + multiple, return NULL_TREE. + Otherwise return EXPR. */ + +tree +expr_single (tree expr) +{ + if (expr == NULL_TREE) + return expr; + + if (TREE_CODE (expr) == STATEMENT_LIST) + { + /* With -gstatement-frontiers we could have a STATEMENT_LIST with + DEBUG_BEGIN_STMT(s) and only a single other stmt, which with + -g wouldn't be present and we'd have that single other stmt + directly instead. */ + struct tree_statement_list_node *n = STATEMENT_LIST_HEAD (expr); + if (!n) + return NULL_TREE; + while (TREE_CODE (n->stmt) == DEBUG_BEGIN_STMT) + { + n = n->next; + if (!n) + return NULL_TREE; + } + expr = n->stmt; + do + { + n = n->next; + if (!n) + return expr_single (expr); + } + while (TREE_CODE (n->stmt) == DEBUG_BEGIN_STMT); + return NULL_TREE; + } + + return expr; +} + #include "gt-tree-iterator.h" --- gcc/tree.c.jj 2020-03-26 10:35:29.984667559 +0100 +++ gcc/tree.c 2020-04-01 16:59:01.689453490 +0200 @@ -5148,30 +5148,9 @@ protected_set_expr_location (tree t, loc SET_EXPR_LOCATION (t, loc); else if (t && TREE_CODE (t) == STATEMENT_LIST) { - /* With -gstatement-frontiers we could have a STATEMENT_LIST with - DEBUG_BEGIN_STMT(s) and only a single other stmt, which with - -g wouldn't be present and we'd have that single other stmt - directly instead. */ - struct tree_statement_list_node *n = STATEMENT_LIST_HEAD (t); - if (!n) - return; - while (TREE_CODE (n->stmt) == DEBUG_BEGIN_STMT) - { - n = n->next; - if (!n) - return; - } - tree t2 = n->stmt; - do - { - n = n->next; - if (!n) - { - protected_set_expr_location (t2, loc); - return; - } - } - while (TREE_CODE (n->stmt) == DEBUG_BEGIN_STMT); + t = expr_single (t); + if (t && CAN_HAVE_LOCATION_P (t)) + SET_EXPR_LOCATION (t, loc); } } --- gcc/cp/parser.c.jj 2020-03-29 11:14:41.087556278 +0200 +++ gcc/cp/parser.c 2020-04-01 17:03:00.730988186 +0200 @@ -39149,8 +39149,9 @@ cp_parser_omp_for_loop (cp_parser *parse incr = cp_parser_omp_for_incr (parser, real_decl); else incr = cp_parser_expression (parser); - if (!EXPR_HAS_LOCATION (incr)) - protected_set_expr_location (incr, input_location); + if (tree incrl = expr_single (incr)) + if (!EXPR_HAS_LOCATION (incrl)) + protected_set_expr_location (incrl, input_location); } parse_close_paren: --- gcc/cp/cp-gimplify.c.jj 2020-03-29 11:14:41.057556738 +0200 +++ gcc/cp/cp-gimplify.c 2020-04-01 17:01:28.916319192 +0200 @@ -226,8 +226,9 @@ genericize_if_stmt (tree *stmt_p) stmt = else_; else stmt = build3 (COND_EXPR, void_type_node, cond, then_, else_); - if (!EXPR_HAS_LOCATION (stmt)) - protected_set_expr_location (stmt, locus); + if (tree stmtl = expr_single (stmt)) + if (!EXPR_HAS_LOCATION (stmtl)) + protected_set_expr_location (stmtl, locus); *stmt_p = stmt; } @@ -248,8 +249,9 @@ genericize_cp_loop (tree *stmt_p, locati tree stmt_list = NULL; tree debug_begin = NULL; - if (EXPR_LOCATION (incr) == UNKNOWN_LOCATION) - protected_set_expr_location (incr, start_locus); + if (tree incrl = expr_single (incr)) + if (!EXPR_HAS_LOCATION (incrl)) + protected_set_expr_location (incrl, start_locus); cp_walk_tree (&cond, cp_genericize_r, data, NULL); cp_walk_tree (&incr, cp_genericize_r, data, NULL); --- gcc/testsuite/g++.dg/opt/pr94441.C.jj 2020-04-01 17:13:43.014677438 +0200 +++ gcc/testsuite/g++.dg/opt/pr94441.C 2020-04-01 17:14:33.495946020 +0200 @@ -0,0 +1,16 @@ +// PR debug/94441 +// { dg-do compile } +// { dg-options "-O3 -fno-forward-propagate --param=max-cse-insns=0 -flive-range-shrinkage -std=c++17 -fcompare-debug" } + +template <class,class> struct Same; +template <class T> struct Same<T,T> {}; + +auto f() +{ + if constexpr (sizeof(int)==3) + return 42; + else + return 42L; +} + +Same<decltype(f()), long> s;
Hi! My recent protected_set_expr_location changes work well when that function is called unconditionally, but as the testcase shows, the C++ FE has a few spots that do: if (!EXPR_HAS_LOCATION (stmt)) protected_set_expr_location (stmt, locus); or similar. Now, if we have for -g0 stmt of some expression that can have location and has != UNKNOWN_LOCATION, while -g instead has a STATEMENT_LIST containing some DEBUG_BEGIN_STMTs + that expression with that location, we don't call protected_set_expr_location in the -g0 case, but do call it in the -g case, because on the STATEMENT_LIST !EXPR_HAS_LOCATION. The following patch introduces a helper function which digs up the single expression of a STATEMENT_LIST and uses that expression in the EXPR_HAS_LOCATION check (plus changes protected_set_expr_location to also use that helper). Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? Or do we want a further wrapper, perhaps C++ FE only, that would do this protected_set_expr_location_if_unset (stmt, locus)? 2020-04-02 Jakub Jelinek <jakub@redhat.com> PR debug/94441 * tree-iterator.h (expr_single): Declare. * tree-iterator.c (expr_single): New function. * tree.c (protected_set_expr_location): Use it. * parser.c (cp_parser_omp_for_loop): Use expr_single. * cp-gimplify.c (genericize_if_stmt, genericize_cp_loop): Likewise. * g++.dg/opt/pr94441.C: New test. Jakub