@@ -17172,6 +17172,53 @@ noop_record_line (struct subfile *subfile, int line, CORE_ADDR pc)
return;
}
+/* Return non-zero if we should add LINE to the line number table.
+ LINE is the line to add, LAST_LINE is the last line that was added,
+ LAST_SUBFILE is the subfile for LAST_LINE.
+ LINE_HAS_NON_ZERO_DISCRIMINATOR is non-zero if LINE has ever
+ had a non-zero discriminator.
+
+ We have to be careful in the presence of discriminators.
+ E.g., for this line:
+
+ for (i = 0; i < 100000; i++);
+
+ clang can emit four line number entries for that one line,
+ each with a different discriminator.
+ See gdb.dwarf2/dw2-single-line-discriminators.exp for an example.
+
+ However, we want gdb to coalesce all four entries into one.
+ Otherwise the user could stepi into the middle of the line and
+ gdb would get confused about whether the pc really was in the
+ middle of the line.
+
+ Things are further complicated by the fact that two consecutive
+ line number entries for the same line is a heuristic used by gcc
+ to denote the end of the prologue. So we can't just discard duplicate
+ entries, we have to be selective about it. The heuristic we use is
+ that we only collapse consecutive entries for the same line if at least
+ one of those entries has a non-zero discriminator. PR 17276.
+
+ Note: Addresses in the line number state machine can never go backwards
+ within one sequence, thus this coalescing is ok. */
+
+static int
+dwarf_record_line_p (unsigned int line, unsigned int last_line,
+ int line_has_non_zero_discriminator,
+ struct subfile *last_subfile)
+{
+ if (current_subfile != last_subfile)
+ return 1;
+ if (line != last_line)
+ return 1;
+ /* Same line for the same file that we've seen already.
+ As a last check, for pr 17276, only record the line if the line
+ has never had a non-zero discriminator. */
+ if (!line_has_non_zero_discriminator)
+ return 1;
+ return 0;
+}
+
/* Use P_RECORD_LINE to record line number LINE beginning at address ADDRESS
in the line table of subfile SUBFILE. */
@@ -17232,6 +17279,12 @@ dwarf_decode_lines_1 (struct line_header *lh, const char *comp_dir,
int is_stmt = lh->default_is_stmt;
int end_sequence = 0;
unsigned char op_index = 0;
+ unsigned int discriminator = 0;
+ /* The last line number that was recorded, used to coalesce
+ consecutive entries for the same line. This can happen, for
+ example, when discriminators are present. PR 17276. */
+ unsigned int last_line = 0;
+ int line_has_non_zero_discriminator = 0;
if (!decode_for_pst_p && lh->num_file_names >= file)
{
@@ -17263,6 +17316,7 @@ dwarf_decode_lines_1 (struct line_header *lh, const char *comp_dir,
{
/* Special opcode. */
unsigned char adj_opcode;
+ int line_delta;
adj_opcode = op_code - lh->opcode_base;
address += (((op_index + (adj_opcode / lh->line_range))
@@ -17270,7 +17324,10 @@ dwarf_decode_lines_1 (struct line_header *lh, const char *comp_dir,
* lh->minimum_instruction_length);
op_index = ((op_index + (adj_opcode / lh->line_range))
% lh->maximum_ops_per_instruction);
- line += lh->line_base + (adj_opcode % lh->line_range);
+ line_delta = lh->line_base + (adj_opcode % lh->line_range);
+ line += line_delta;
+ if (line_delta != 0)
+ line_has_non_zero_discriminator = discriminator != 0;
if (lh->num_file_names < file || file == 0)
dwarf2_debug_line_missing_file_complaint ();
/* For now we ignore lines not starting on an
@@ -17284,13 +17341,19 @@ dwarf_decode_lines_1 (struct line_header *lh, const char *comp_dir,
{
dwarf_finish_line (gdbarch, last_subfile,
address, p_record_line);
- last_subfile = current_subfile;
}
- /* Append row to matrix using current values. */
- dwarf_record_line (gdbarch, current_subfile,
- line, address, p_record_line);
+ if (dwarf_record_line_p (line, last_line,
+ line_has_non_zero_discriminator,
+ last_subfile))
+ {
+ dwarf_record_line (gdbarch, current_subfile,
+ line, address, p_record_line);
+ }
+ last_subfile = current_subfile;
+ last_line = line;
}
}
+ discriminator = 0;
}
else switch (op_code)
{
@@ -17353,8 +17416,14 @@ dwarf_decode_lines_1 (struct line_header *lh, const char *comp_dir,
break;
case DW_LNE_set_discriminator:
/* The discriminator is not interesting to the debugger;
- just ignore it. */
- line_ptr = extended_end;
+ just ignore it. We still need to check its value though:
+ if there are consecutive entries for the same
+ (non-prologue) line we want to coalesce them.
+ PR 17276. */
+ discriminator = read_unsigned_leb128 (abfd, line_ptr,
+ &bytes_read);
+ line_has_non_zero_discriminator |= discriminator != 0;
+ line_ptr += bytes_read;
break;
default:
complaint (&symfile_complaints,
@@ -17383,12 +17452,19 @@ dwarf_decode_lines_1 (struct line_header *lh, const char *comp_dir,
{
dwarf_finish_line (gdbarch, last_subfile,
address, p_record_line);
- last_subfile = current_subfile;
}
- dwarf_record_line (gdbarch, current_subfile,
- line, address, p_record_line);
+ if (dwarf_record_line_p (line, last_line,
+ line_has_non_zero_discriminator,
+ last_subfile))
+ {
+ dwarf_record_line (gdbarch, current_subfile,
+ line, address, p_record_line);
+ }
+ last_subfile = current_subfile;
+ last_line = line;
}
}
+ discriminator = 0;
break;
case DW_LNS_advance_pc:
{
@@ -17404,8 +17480,15 @@ dwarf_decode_lines_1 (struct line_header *lh, const char *comp_dir,
}
break;
case DW_LNS_advance_line:
- line += read_signed_leb128 (abfd, line_ptr, &bytes_read);
- line_ptr += bytes_read;
+ {
+ int line_delta
+ = read_signed_leb128 (abfd, line_ptr, &bytes_read);
+
+ line += line_delta;
+ if (line_delta != 0)
+ line_has_non_zero_discriminator = discriminator != 0;
+ line_ptr += bytes_read;
+ }
break;
case DW_LNS_set_file:
{
@@ -17427,6 +17510,7 @@ dwarf_decode_lines_1 (struct line_header *lh, const char *comp_dir,
if (!decode_for_pst_p)
{
last_subfile = current_subfile;
+ line_has_non_zero_discriminator = discriminator != 0;
dwarf2_start_subfile (fe->name, dir, comp_dir);
}
}
new file mode 100644
@@ -0,0 +1,281 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2014 Free Software Foundation, Inc.
+
+ This program 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 of the License, or
+ (at your option) any later version.
+
+ This program 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 this program. If not, see <http://www.gnu.org/licenses/>. */
+
+/* This was made from dw2-single-line-discriminators.c using
+ clang -dA -S -g
+ and then hand-editing the assembly a bit (simplify paths,
+ tweak so gas accepts it). */
+
+ .text
+ .file "dw2-single-line-discriminators.c"
+ .section .debug_info,"",@progbits
+.Lsection_info:
+ .section .debug_abbrev,"",@progbits
+.Lsection_abbrev:
+ .section .debug_line,"",@progbits
+.Lsection_line:
+ .section .debug_pubnames,"",@progbits
+ .section .debug_pubtypes,"",@progbits
+ .section .debug_str,"MS",@progbits,1
+.Linfo_string:
+ .section .debug_loc,"",@progbits
+.Lsection_debug_loc:
+ .section .debug_ranges,"",@progbits
+.Ldebug_range:
+ .file 1 "gdb.dwarf2/dw2-single-line-discriminators.c"
+ .text
+ .globl main
+ .align 16, 0x90
+ .type main,@function
+main: # @main
+.Lfunc_begin0:
+ .loc 1 22 0 # dw2-single-line-discriminators.c:22:0
+ .cfi_startproc
+# BB#0:
+ pushq %rbp
+.Ltmp0:
+ .cfi_def_cfa_offset 16
+.Ltmp1:
+ .cfi_offset %rbp, -16
+ movq %rsp, %rbp
+.Ltmp2:
+ .cfi_def_cfa_register %rbp
+ movl $0, -4(%rbp)
+ .loc 1 26 3 prologue_end # dw2-single-line-discriminators.c:26:3
+.Ltmp3:
+ movl $0, x
+ .loc 1 28 8 # dw2-single-line-discriminators.c:28:8
+.Ltmp4:
+ movl $0, -8(%rbp)
+.LBB0_1: # =>This Inner Loop Header: Depth=1
+ .loc 1 28 8 discriminator 4 # dw2-single-line-discriminators.c:28:8
+.Ltmp5:
+ cmpl $10, -8(%rbp)
+ jge .LBB0_4
+.Ltmp6:
+# BB#2: # in Loop: Header=BB0_1 Depth=1
+ .loc 1 28 28 discriminator 2 # dw2-single-line-discriminators.c:28:28
+ jmp .LBB0_3
+.Ltmp7:
+.LBB0_3: # in Loop: Header=BB0_1 Depth=1
+ .loc 1 28 23 discriminator 3 # dw2-single-line-discriminators.c:28:23
+ movl -8(%rbp), %eax
+ addl $1, %eax
+ movl %eax, -8(%rbp)
+ jmp .LBB0_1
+.Ltmp8:
+.LBB0_4:
+ movl $0, %eax
+ .loc 1 30 3 # dw2-single-line-discriminators.c:30:3
+ popq %rbp
+ retq
+.Ltmp9:
+.Ltmp10:
+ .size main, .Ltmp10-main
+.Lfunc_end0:
+ .cfi_endproc
+
+ .type x,@object # @x
+ .comm x,4,4
+.Ldebug_end1:
+ .section .debug_str,"MS",@progbits,1
+.Linfo_string0:
+ .asciz "clang version (trunk r215195)"
+.Linfo_string1:
+ .asciz "dw2-single-line-discriminators.c"
+.Linfo_string2:
+ .asciz "/tmp/obj/gdb/testsuite"
+.Linfo_string3:
+ .asciz "x"
+.Linfo_string4:
+ .asciz "int"
+.Linfo_string5:
+ .asciz "main"
+.Linfo_string6:
+ .asciz "i"
+ .section .debug_info,"",@progbits
+.L.debug_info_begin0:
+ .long 108 # Length of Unit
+ .short 4 # DWARF version number
+ .long .Lsection_abbrev # Offset Into Abbrev. Section
+ .byte 8 # Address Size (in bytes)
+ .byte 1 # Abbrev [1] 0xb:0x65 DW_TAG_compile_unit
+ .long .Linfo_string0 # DW_AT_producer
+ .short 12 # DW_AT_language
+ .long .Linfo_string1 # DW_AT_name
+ .long .Lline_table_start0 # DW_AT_stmt_list
+ .long .Linfo_string2 # DW_AT_comp_dir
+ .quad .Lfunc_begin0 # DW_AT_low_pc
+.Lset0 = .Lfunc_end0-.Lfunc_begin0 # DW_AT_high_pc
+ .long .Lset0
+ .byte 2 # Abbrev [2] 0x2a:0x15 DW_TAG_variable
+ .long .Linfo_string3 # DW_AT_name
+ .long 63 # DW_AT_type
+ # DW_AT_external
+ .byte 1 # DW_AT_decl_file
+ .byte 18 # DW_AT_decl_line
+ .byte 9 # DW_AT_location
+ .byte 3
+ .quad x
+ .byte 3 # Abbrev [3] 0x3f:0x7 DW_TAG_base_type
+ .long .Linfo_string4 # DW_AT_name
+ .byte 5 # DW_AT_encoding
+ .byte 4 # DW_AT_byte_size
+ .byte 4 # Abbrev [4] 0x46:0x29 DW_TAG_subprogram
+ .quad .Lfunc_begin0 # DW_AT_low_pc
+.Lset1 = .Lfunc_end0-.Lfunc_begin0 # DW_AT_high_pc
+ .long .Lset1
+ .byte 1 # DW_AT_frame_base
+ .byte 86
+ .long .Linfo_string5 # DW_AT_name
+ .byte 1 # DW_AT_decl_file
+ .byte 21 # DW_AT_decl_line
+ .long 63 # DW_AT_type
+ # DW_AT_external
+ .byte 1 # DW_AT_accessibility
+ # DW_ACCESS_public
+ .byte 5 # Abbrev [5] 0x60:0xe DW_TAG_variable
+ .byte 2 # DW_AT_location
+ .byte 145
+ .byte 120
+ .long .Linfo_string6 # DW_AT_name
+ .byte 1 # DW_AT_decl_file
+ .byte 23 # DW_AT_decl_line
+ .long 63 # DW_AT_type
+ .byte 0 # End Of Children Mark
+ .byte 0 # End Of Children Mark
+.L.debug_info_end0:
+ .section .debug_abbrev,"",@progbits
+ .byte 1 # Abbreviation Code
+ .byte 17 # DW_TAG_compile_unit
+ .byte 1 # DW_CHILDREN_yes
+ .byte 37 # DW_AT_producer
+ .byte 14 # DW_FORM_strp
+ .byte 19 # DW_AT_language
+ .byte 5 # DW_FORM_data2
+ .byte 3 # DW_AT_name
+ .byte 14 # DW_FORM_strp
+ .byte 16 # DW_AT_stmt_list
+ .byte 23 # DW_FORM_sec_offset
+ .byte 27 # DW_AT_comp_dir
+ .byte 14 # DW_FORM_strp
+ .byte 17 # DW_AT_low_pc
+ .byte 1 # DW_FORM_addr
+ .byte 18 # DW_AT_high_pc
+ .byte 6 # DW_FORM_data4
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 2 # Abbreviation Code
+ .byte 52 # DW_TAG_variable
+ .byte 0 # DW_CHILDREN_no
+ .byte 3 # DW_AT_name
+ .byte 14 # DW_FORM_strp
+ .byte 73 # DW_AT_type
+ .byte 19 # DW_FORM_ref4
+ .byte 63 # DW_AT_external
+ .byte 25 # DW_FORM_flag_present
+ .byte 58 # DW_AT_decl_file
+ .byte 11 # DW_FORM_data1
+ .byte 59 # DW_AT_decl_line
+ .byte 11 # DW_FORM_data1
+ .byte 2 # DW_AT_location
+ .byte 24 # DW_FORM_exprloc
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 3 # Abbreviation Code
+ .byte 36 # DW_TAG_base_type
+ .byte 0 # DW_CHILDREN_no
+ .byte 3 # DW_AT_name
+ .byte 14 # DW_FORM_strp
+ .byte 62 # DW_AT_encoding
+ .byte 11 # DW_FORM_data1
+ .byte 11 # DW_AT_byte_size
+ .byte 11 # DW_FORM_data1
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 4 # Abbreviation Code
+ .byte 46 # DW_TAG_subprogram
+ .byte 1 # DW_CHILDREN_yes
+ .byte 17 # DW_AT_low_pc
+ .byte 1 # DW_FORM_addr
+ .byte 18 # DW_AT_high_pc
+ .byte 6 # DW_FORM_data4
+ .byte 64 # DW_AT_frame_base
+ .byte 24 # DW_FORM_exprloc
+ .byte 3 # DW_AT_name
+ .byte 14 # DW_FORM_strp
+ .byte 58 # DW_AT_decl_file
+ .byte 11 # DW_FORM_data1
+ .byte 59 # DW_AT_decl_line
+ .byte 11 # DW_FORM_data1
+ .byte 73 # DW_AT_type
+ .byte 19 # DW_FORM_ref4
+ .byte 63 # DW_AT_external
+ .byte 25 # DW_FORM_flag_present
+ .byte 50 # DW_AT_accessibility
+ .byte 11 # DW_FORM_data1
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 5 # Abbreviation Code
+ .byte 52 # DW_TAG_variable
+ .byte 0 # DW_CHILDREN_no
+ .byte 2 # DW_AT_location
+ .byte 24 # DW_FORM_exprloc
+ .byte 3 # DW_AT_name
+ .byte 14 # DW_FORM_strp
+ .byte 58 # DW_AT_decl_file
+ .byte 11 # DW_FORM_data1
+ .byte 59 # DW_AT_decl_line
+ .byte 11 # DW_FORM_data1
+ .byte 73 # DW_AT_type
+ .byte 19 # DW_FORM_ref4
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 0 # EOM(3)
+ .section .debug_ranges,"",@progbits
+ .section .debug_loc,"",@progbits
+ .section .debug_pubnames,"",@progbits
+.Lset2 = .LpubNames_end0-.LpubNames_begin0 # Length of Public Names Info
+ .long .Lset2
+.LpubNames_begin0:
+ .short 2 # DWARF Version
+ .long .L.debug_info_begin0 # Offset of Compilation Unit Info
+.Lset3 = .L.debug_info_end0-.L.debug_info_begin0 # Compilation Unit Length
+ .long .Lset3
+ .long 70 # DIE offset
+ .asciz "main" # External Name
+ .long 42 # DIE offset
+ .asciz "x" # External Name
+ .long 0 # End Mark
+.LpubNames_end0:
+ .section .debug_pubtypes,"",@progbits
+.Lset4 = .LpubTypes_end0-.LpubTypes_begin0 # Length of Public Types Info
+ .long .Lset4
+.LpubTypes_begin0:
+ .short 2 # DWARF Version
+ .long .L.debug_info_begin0 # Offset of Compilation Unit Info
+.Lset5 = .L.debug_info_end0-.L.debug_info_begin0 # Compilation Unit Length
+ .long .Lset5
+ .long 63 # DIE offset
+ .asciz "int" # External Name
+ .long 0 # End Mark
+.LpubTypes_end0:
+
+ .ident "clang version (trunk r215195)"
+ .section ".note.GNU-stack","",@progbits
+ .section .debug_line,"",@progbits
+.Lline_table_start0:
new file mode 100644
@@ -0,0 +1,31 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2014 Free Software Foundation, Inc.
+
+ This program 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 of the License, or
+ (at your option) any later version.
+
+ This program 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 this program. If not, see <http://www.gnu.org/licenses/>. */
+
+int x;
+
+int
+main ()
+{
+ int i;
+
+ /* Ensure runto_main stops before the for loop. */
+ x = 0;
+
+ for (i = 0; i < 10; ++i) continue; /* stepi line */
+
+ return 0;
+}
new file mode 100644
@@ -0,0 +1,49 @@
+# Copyright 2012-2014 Free Software Foundation, Inc.
+
+# This program 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 of the License, or
+# (at your option) any later version.
+#
+# This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+
+# Test gdb's coalescing of multiple line number entries for the same line
+# but with different discriminators. PR 17276.
+
+load_lib dwarf.exp
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+if ![dwarf2_support] {
+ return 0
+}
+
+# This test can only be run on x86-64 targets.
+if {![istarget x86_64-*] || ![is_lp64_target]} {
+ return 0
+}
+
+standard_testfile .S
+set csrcfile ${testfile}.c
+
+if { [prepare_for_testing "${testfile}.exp" "${testfile}" $srcfile {nodebug}] } {
+ return -1
+}
+
+if ![runto_main] then {
+ fail "Cannot run to main."
+ continue
+}
+
+set srcline [gdb_get_line_number "stepi line" $csrcfile]
+gdb_breakpoint $srcline
+gdb_continue_to_breakpoint "stepi line"
+
+# A stepi will land us in the middle of the line, and thus
+# gdb should print the pc value.
+gdb_test "stepi" "$hex\[ \t\]+$srcline\[ \t\]+\[^\r\n\]+"