Check function is GC'ed
I see the following fail on arm-none-eabi target,
(gdb) b 24^M
Breakpoint 1 at 0x4: file
../../../../git/gdb/testsuite/gdb.base/break-on-linker-gcd-function.cc,
line 24.^M
(gdb) FAIL: gdb.base/break-on-linker-gcd-function.exp: b 24
Currently, we are using flag has_section_at_zero to determine whether
address zero in debug info means the corresponding code has been
GC'ed, like this:
case DW_LNE_set_address:
address = read_address (abfd, line_ptr, cu, &bytes_read);
if (address == 0 && !dwarf2_per_objfile->has_section_at_zero)
{
/* This line table is for a function which has been
GCd by the linker. Ignore it. PR gdb/12528 */
However, this is incorrect on some bare metal targets, as .text
section is located at 0x0, so dwarf2_per_objfile->has_section_at_zero
is true. If a function is GC'ed by linker, the address is zero. GDB
thinks address zero is a function's address rather than this function
is GC'ed.
In this patch, we choose 'lowpc' got in read_file_scope to check
whether 'lowpc' is greater than zero. If it isn't, address zero really
means the function is GC'ed. In this patch, we pass 'lowpc' in
read_file_scope through handle_DW_AT_stmt_list and dwarf_decode_lines,
and to dwarf_decode_lines_1 finally.
This patch fixes the fail above. This patch also covers the path that
partial symbol isn't used, which is tested by starting gdb with
--readnow option.
It is regression tested on x86-linux with
target_board=dwarf4-gdb-index, and arm-none-eabi. OK to apply?
gdb:
2014-09-19 Yao Qi <yao@codesourcery.com>
* dwarf2read.c (dwarf_decode_lines): Update declaration.
(handle_DW_AT_stmt_list): Add argument 'lowpc'. Update
comments. Callers update.
(dwarf_decode_lines): Likewise.
(dwarf_decode_lines_1): Add argument 'lowpc'. Update
comments. Skip the line table if 'lowpc' is greater than
'address'. Don't check
dwarf2_per_objfile->has_section_at_zero.
gdb/testsuite:
2014-09-19 Yao Qi <yao@codesourcery.com>
* gdb.base/break-on-linker-gcd-function.exp: Move test into new
proc set_breakpoint_on_gcd_function. Invoke
set_breakpoint_on_gcd_function. Restart GDB with --readnow and
invoke set_breakpoint_on_gcd_function again.
This commit is contained in:
Yao Qi
parent
8e635c209b
commit
c3b7b696c2
4 changed files with 59 additions and 16 deletions
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@ -1,3 +1,14 @@
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2014-09-19 Yao Qi <yao@codesourcery.com>
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* dwarf2read.c (dwarf_decode_lines): Update declaration.
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(handle_DW_AT_stmt_list): Add argument 'lowpc'. Update
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comments. Callers update.
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(dwarf_decode_lines): Likewise.
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(dwarf_decode_lines_1): Add argument 'lowpc'. Update
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comments. Skip the line table if 'lowpc' is greater than
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'address'. Don't check
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dwarf2_per_objfile->has_section_at_zero.
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2014-09-18 Doug Evans <dje@google.com>
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* NEWS: Mention new "producer" attribute of gdb.Symtab.
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@ -1512,7 +1512,8 @@ static struct line_header *dwarf_decode_line_header (unsigned int offset,
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struct dwarf2_cu *cu);
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static void dwarf_decode_lines (struct line_header *, const char *,
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struct dwarf2_cu *, struct partial_symtab *);
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struct dwarf2_cu *, struct partial_symtab *,
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CORE_ADDR);
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static void dwarf2_start_subfile (const char *, const char *, const char *);
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@ -4448,7 +4449,7 @@ dwarf2_build_include_psymtabs (struct dwarf2_cu *cu,
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return; /* No linetable, so no includes. */
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/* NOTE: pst->dirname is DW_AT_comp_dir (if present). */
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dwarf_decode_lines (lh, pst->dirname, cu, pst);
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dwarf_decode_lines (lh, pst->dirname, cu, pst, pst->textlow);
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free_line_header (lh);
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}
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@ -8967,11 +8968,12 @@ find_file_and_directory (struct die_info *die, struct dwarf2_cu *cu,
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/* Handle DW_AT_stmt_list for a compilation unit.
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DIE is the DW_TAG_compile_unit die for CU.
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COMP_DIR is the compilation directory. */
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COMP_DIR is the compilation directory. LOWPC is passed to
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dwarf_decode_lines. See dwarf_decode_lines comments about it. */
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static void
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handle_DW_AT_stmt_list (struct die_info *die, struct dwarf2_cu *cu,
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const char *comp_dir) /* ARI: editCase function */
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const char *comp_dir, CORE_ADDR lowpc) /* ARI: editCase function */
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{
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struct attribute *attr;
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@ -8988,7 +8990,7 @@ handle_DW_AT_stmt_list (struct die_info *die, struct dwarf2_cu *cu,
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{
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cu->line_header = line_header;
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make_cleanup (free_cu_line_header, cu);
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dwarf_decode_lines (line_header, comp_dir, cu, NULL);
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dwarf_decode_lines (line_header, comp_dir, cu, NULL, lowpc);
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}
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}
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}
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@ -9039,7 +9041,7 @@ read_file_scope (struct die_info *die, struct dwarf2_cu *cu)
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/* Decode line number information if present. We do this before
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processing child DIEs, so that the line header table is available
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for DW_AT_decl_file. */
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handle_DW_AT_stmt_list (die, cu, comp_dir);
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handle_DW_AT_stmt_list (die, cu, comp_dir, lowpc);
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/* Process all dies in compilation unit. */
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if (die->child != NULL)
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@ -17252,7 +17254,8 @@ dwarf_finish_line (struct gdbarch *gdbarch, struct subfile *subfile,
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static void
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dwarf_decode_lines_1 (struct line_header *lh, const char *comp_dir,
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struct dwarf2_cu *cu, const int decode_for_pst_p)
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struct dwarf2_cu *cu, const int decode_for_pst_p,
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CORE_ADDR lowpc)
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{
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const gdb_byte *line_ptr, *extended_end;
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const gdb_byte *line_end;
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@ -17375,7 +17378,12 @@ dwarf_decode_lines_1 (struct line_header *lh, const char *comp_dir,
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case DW_LNE_set_address:
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address = read_address (abfd, line_ptr, cu, &bytes_read);
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if (address == 0 && !dwarf2_per_objfile->has_section_at_zero)
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/* If address < lowpc then it's not a usable value, it's
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outside the pc range of the CU. However, we restrict
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the test to only address values of zero to preserve
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GDB's previous behaviour which is to handle the specific
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case of a function being GC'd by the linker. */
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if (address == 0 && address < lowpc)
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{
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/* This line table is for a function which has been
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GCd by the linker. Ignore it. PR gdb/12528 */
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@ -17595,17 +17603,20 @@ dwarf_decode_lines_1 (struct line_header *lh, const char *comp_dir,
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as the corresponding symtab. Since COMP_DIR is not used in the name of the
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symtab we don't use it in the name of the psymtabs we create.
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E.g. expand_line_sal requires this when finding psymtabs to expand.
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A good testcase for this is mb-inline.exp. */
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A good testcase for this is mb-inline.exp.
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LOWPC is the lowest address in CU (or 0 if not known). */
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static void
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dwarf_decode_lines (struct line_header *lh, const char *comp_dir,
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struct dwarf2_cu *cu, struct partial_symtab *pst)
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struct dwarf2_cu *cu, struct partial_symtab *pst,
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CORE_ADDR lowpc)
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{
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struct objfile *objfile = cu->objfile;
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const int decode_for_pst_p = (pst != NULL);
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struct subfile *first_subfile = current_subfile;
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dwarf_decode_lines_1 (lh, comp_dir, cu, decode_for_pst_p);
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dwarf_decode_lines_1 (lh, comp_dir, cu, decode_for_pst_p, lowpc);
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if (decode_for_pst_p)
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{
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@ -1,3 +1,10 @@
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2014-09-19 Yao Qi <yao@codesourcery.com>
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* gdb.base/break-on-linker-gcd-function.exp: Move test into new
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proc set_breakpoint_on_gcd_function. Invoke
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set_breakpoint_on_gcd_function. Restart GDB with --readnow and
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invoke set_breakpoint_on_gcd_function again.
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2014-09-18 Doug Evans <dje@google.com>
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* gdb.dwarf2/symtab-producer.exp: New file.
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@ -41,9 +41,23 @@ if {[build_executable_from_specs $testfile.exp $testfile \
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clean_restart $testfile
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# Single hex digit
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set xd {[0-9a-f]}
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proc set_breakpoint_on_gcd_function {} {
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# Single hex digit
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set xd {[0-9a-f]}
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# This accepts e.g. "Breakpoint 1 at 0x40968a" (fixed GDB)
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# but rejects e.g. "Breakpoint 1 at 0x4" (broken GDB).
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gdb_test "b [gdb_get_line_number "gdb break here"]" "Breakpoint \[0-9\] at 0x${xd}${xd}+: .*"
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# This accepts e.g. "Breakpoint 1 at 0x40968a" (fixed GDB)
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# but rejects e.g. "Breakpoint 1 at 0x4" (broken GDB).
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gdb_test "b [gdb_get_line_number "gdb break here"]" \
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"Breakpoint \[0-9\] at 0x${xd}${xd}+: .*"
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}
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set_breakpoint_on_gcd_function
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set saved_gdbflags $GDBFLAGS
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set GDBFLAGS "$GDBFLAGS --readnow"
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clean_restart ${testfile}
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set GDBFLAGS $saved_gdbflags
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with_test_prefix "readnow" {
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set_breakpoint_on_gcd_function
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}
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