From bc7b0ffa6335f22ae91101d5b072871ebbdc5013 Mon Sep 17 00:00:00 2001 From: Alexandre Oliva Date: Thu, 8 Mar 2018 08:27:56 +0000 Subject: [PATCH] [LVU] reset view at function entry, omit views at line zero Location views might be associated with locations that lack line number information (line number zero), but since we omit .loc directives that would have been issued with line number zero, we also omit the symbolic view numbers that would have been issued at such points. Resetting views at function entry points address some of these issues, and alleviate the huge chains of symbolic views that have burdened assemblers since we disabled -ginternal-reset-location-views by default, but other problems of undefined views remain when it's not the whole function that lacks line number info, just parts of it. So, when we encounter a request to output a view that may have been referenced, but we decide to omit the .loc because the line is zero, we will now omit the view as well, i.e., we will internally regard that view as zero-numbered. for gcc/ChangeLog PR debug/84404 PR debug/84408 * dwarf2out.c (struct dw_line_info_table): Update comments for view == -1. (FORCE_RESET_NEXT_VIEW): New. (FORCE_RESETTING_VIEW_P): New. (RESETTING_VIEW_P): Check for -1 too. (ZERO_VIEW_P): Likewise. (new_line_info_table): Force-reset next view. (dwarf2out_begin_function): Likewise. (dwarf2out_source_line): Simplify zero_view_p initialization. Test FORCE_RESETTING_VIEW_P and RESETTING_VIEW_P instead of view directly. Omit view when omitting .loc at line 0. for gcc/testsuite/ChangeLog PR debug/84404 PR debug/84408 * gcc.dg/graphite/pr84404.c: New. From-SVN: r258355 --- gcc/ChangeLog | 16 ++++++ gcc/dwarf2out.c | 89 +++++++++++++++++++++++++-------- gcc/testsuite/ChangeLog | 6 +++ gcc/testsuite/gcc.dg/graphite/pr84404.c | 18 +++++++ 4 files changed, 109 insertions(+), 20 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/graphite/pr84404.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 39587da..17ca051 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,19 @@ +2018-03-08 Alexandre Oliva + + PR debug/84404 + PR debug/84408 + * dwarf2out.c (struct dw_line_info_table): Update comments for + view == -1. + (FORCE_RESET_NEXT_VIEW): New. + (FORCE_RESETTING_VIEW_P): New. + (RESETTING_VIEW_P): Check for -1 too. + (ZERO_VIEW_P): Likewise. + (new_line_info_table): Force-reset next view. + (dwarf2out_begin_function): Likewise. + (dwarf2out_source_line): Simplify zero_view_p initialization. + Test FORCE_RESETTING_VIEW_P and RESETTING_VIEW_P instead of + view directly. Omit view when omitting .loc at line 0. + 2018-03-08 Jakub Jelinek PR tree-optimization/84740 diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c index 41bb115..0348f44 100644 --- a/gcc/dwarf2out.c +++ b/gcc/dwarf2out.c @@ -2940,8 +2940,8 @@ struct GTY(()) dw_line_info_table { If it is 0, it is known that the NEXT view will be the first view at the given PC. - If it is -1, we've advanced PC but we haven't emitted a line location yet, - so we shouldn't use this view number. + If it is -1, we're forcing the view number to be reset, e.g. at a + function entry. The meaning of other nonzero values depends on whether we're computing views internally or leaving it for the assembler to do @@ -2951,8 +2951,10 @@ struct GTY(()) dw_line_info_table { going to ask the assembler to assign. */ var_loc_view view; +#define FORCE_RESET_NEXT_VIEW(x) ((x) = (var_loc_view)-1) #define RESET_NEXT_VIEW(x) ((x) = (var_loc_view)0) -#define RESETTING_VIEW_P(x) ((x) == (var_loc_view)0) +#define FORCE_RESETTING_VIEW_P(x) ((x) == (var_loc_view)-1) +#define RESETTING_VIEW_P(x) ((x) == (var_loc_view)0 || FORCE_RESETTING_VIEW_P (x)) vec *entries; }; @@ -2985,7 +2987,7 @@ maybe_reset_location_view (rtx_insn *insn, dw_line_info_table *table) else if (get_attr_min_length (insn) > 0) reset = 1; - if (reset > 0) + if (reset > 0 && !RESETTING_VIEW_P (table->view)) RESET_NEXT_VIEW (table->view); } @@ -3235,9 +3237,10 @@ static GTY(()) bitmap zero_view_p; that must be view number zero. Otherwise, ZERO_VIEW_P is allocated and views label numbers recorded in it are the ones known to be zero. */ -#define ZERO_VIEW_P(N) (zero_view_p \ - ? bitmap_bit_p (zero_view_p, (N)) \ - : (N) == 0) +#define ZERO_VIEW_P(N) ((N) == (var_loc_view)0 \ + || (N) == (var_loc_view)-1 \ + || (zero_view_p \ + && bitmap_bit_p (zero_view_p, (N)))) /* Return true iff we're to emit .loc directives for the assembler to generate line number sections. @@ -27212,6 +27215,18 @@ create_label: last_postcall_label = ggc_strdup (loclabel); } newloc->label = last_postcall_label; + /* ??? This view is at last_label, not last_label-1, but we + could only assume view at last_label-1 is zero if we could + assume calls always have length greater than one. This is + probably true in general, though there might be a rare + exception to this rule, e.g. if a call insn is optimized out + by target magic. Then, even the -1 in the label will be + wrong, which might invalidate the range. Anyway, using view, + though technically possibly incorrect, will work as far as + ranges go: since L-1 is in the middle of the call insn, + (L-1).0 and (L-1).V shouldn't make any difference, and having + the loclist entry refer to the .loc entry might be useful, so + leave it like this. */ newloc->view = view; } @@ -27393,7 +27408,7 @@ new_line_info_table (void) table->file_num = 1; table->line_num = 1; table->is_stmt = DWARF_LINE_DEFAULT_IS_STMT_START; - RESET_NEXT_VIEW (table->view); + FORCE_RESET_NEXT_VIEW (table->view); return table; } @@ -27477,6 +27492,7 @@ dwarf2out_begin_function (tree fun) tail_call_site_count = 0; set_cur_line_info_table (sec); + FORCE_RESET_NEXT_VIEW (cur_line_info_table->view); } /* Helper function of dwarf2out_end_function, called only after emitting @@ -27574,10 +27590,44 @@ dwarf2out_source_line (unsigned int line, unsigned int column, { unsigned int file_num; dw_line_info_table *table; + static var_loc_view lvugid; - if (debug_info_level < DINFO_LEVEL_TERSE || line == 0) + if (debug_info_level < DINFO_LEVEL_TERSE) return; + table = cur_line_info_table; + + if (line == 0) + { + if (debug_variable_location_views + && output_asm_line_debug_info () + && table && !RESETTING_VIEW_P (table->view)) + { + /* If we're using the assembler to compute view numbers, we + can't issue a .loc directive for line zero, so we can't + get a view number at this point. We might attempt to + compute it from the previous view, but since we're + omitting the line number entry, we might as well omit the + view number as well. That means pretending it's a view + number zero, which might very well turn out to be + correct. */ + if (!zero_view_p) + zero_view_p = BITMAP_GGC_ALLOC (); + bitmap_set_bit (zero_view_p, table->view); + if (flag_debug_asm) + { + char label[MAX_ARTIFICIAL_LABEL_BYTES]; + ASM_GENERATE_INTERNAL_LABEL (label, "LVU", table->view); + fprintf (asm_out_file, "\t%s line 0, omitted view ", + ASM_COMMENT_START); + assemble_name (asm_out_file, label); + putc ('\n', asm_out_file); + } + table->view = ++lvugid; + } + return; + } + /* The discriminator column was added in dwarf4. Simplify the below by simply removing it if we're not supposed to output it. */ if (dwarf_version < 4 && dwarf_strict) @@ -27586,7 +27636,6 @@ dwarf2out_source_line (unsigned int line, unsigned int column, if (!debug_column_info) column = 0; - table = cur_line_info_table; file_num = maybe_emit_file (lookup_filename (filename)); /* ??? TODO: Elide duplicate line number entries. Traditionally, @@ -27648,13 +27697,6 @@ dwarf2out_source_line (unsigned int line, unsigned int column, } if (debug_variable_location_views) { - static var_loc_view lvugid; - if (!lvugid) - { - gcc_assert (!zero_view_p); - zero_view_p = BITMAP_GGC_ALLOC (); - bitmap_set_bit (zero_view_p, 0); - } if (!RESETTING_VIEW_P (table->view)) { /* When we're using the assembler to compute view @@ -27675,7 +27717,7 @@ dwarf2out_source_line (unsigned int line, unsigned int column, } else { - if (!table->in_use) + if (FORCE_RESETTING_VIEW_P (table->view)) fputs (" view -0", asm_out_file); else fputs (" view 0", asm_out_file); @@ -27686,6 +27728,8 @@ dwarf2out_source_line (unsigned int line, unsigned int column, known to be zero, because then we may be able to optimize out locviews that are all zeros, so take note of it in zero_view_p. */ + if (!zero_view_p) + zero_view_p = BITMAP_GGC_ALLOC (); bitmap_set_bit (zero_view_p, lvugid); table->view = ++lvugid; } @@ -27698,17 +27742,22 @@ dwarf2out_source_line (unsigned int line, unsigned int column, targetm.asm_out.internal_label (asm_out_file, LINE_CODE_LABEL, label_num); - if (debug_variable_location_views && table->view) + if (debug_variable_location_views && !RESETTING_VIEW_P (table->view)) push_dw_line_info_entry (table, LI_adv_address, label_num); else push_dw_line_info_entry (table, LI_set_address, label_num); if (debug_variable_location_views) { + bool resetting = FORCE_RESETTING_VIEW_P (table->view); + if (resetting) + table->view = 0; + if (flag_debug_asm) fprintf (asm_out_file, "\t%s view %s%d\n", ASM_COMMENT_START, - table->in_use ? "" : "-", + resetting ? "-" : "", table->view); + table->view++; } if (file_num != table->file_num) diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index a42a376..7ba3555 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2018-03-08 Alexandre Oliva + + PR debug/84404 + PR debug/84408 + * gcc.dg/graphite/pr84404.c: New. + 2018-03-08 Jakub Jelinek PR tree-optimization/84740 diff --git a/gcc/testsuite/gcc.dg/graphite/pr84404.c b/gcc/testsuite/gcc.dg/graphite/pr84404.c new file mode 100644 index 0000000..858e651 --- /dev/null +++ b/gcc/testsuite/gcc.dg/graphite/pr84404.c @@ -0,0 +1,18 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -ftree-parallelize-loops=2 -floop-nest-optimize -g" } */ + +int te[9]; + +void +dt (int cz) +{ + while (cz < 1) + { + int xy; + + for (xy = 0; xy < 9; ++xy) + te[xy] = 0; + + ++cz; + } +} -- 2.7.4