projects / packages / gdb.git / blame
| Commit | Line | Data |
|---|---|---|
| f412e1b4 PS |
1 | http://sourceware.org/ml/gdb-patches/2012-02/msg00673.html |
| 2 | Subject: [patch] Fix regression by me for gcc-4.0...gcc-4.4 i386 -O2 -g parameters (PR 13777) | |
| 3 | ||
| 4 | Hi, | |
| 5 | ||
| 6 | http://sourceware.org/bugzilla/show_bug.cgi?id=13777 | |
| 7 | ||
| 8 | for CentOS-5 i386 ls: | |
| 9 | ||
| 10 | $ gdb ls | |
| 11 | (gdb) start | |
| 12 | Temporary breakpoint 1, main (argc=Cannot access memory at address 0x81b7c7cd | |
| 13 | ||
| 14 | instead of GDB before my PR 12573 fix/change: | |
| 15 | ||
| 16 | Temporary breakpoint 1, main (argc=1, ... | |
| 17 | ||
| 18 | I asked before on #gcc since which versions GCC produced DW_AT_location which | |
| 19 | is for any PC either optimized-out or it has valid value. I was told since | |
| 20 | gcc-4.0. But that is not true. | |
| 21 | ||
| 22 | I have bisected gcc and I found 4.4.0 was still broken, 4.5.0 was correct, | |
| 23 | thanks to: | |
| 24 | commit 25e880b1917bd6bbf07e86b5574c698f3e9472d9 | |
| 25 | Author: rth <rth@138bc75d-0d04-0410-961f-82ee72b054a4> | |
| 26 | Date: Sat May 30 00:33:46 2009 +0000 | |
| 27 | git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@147995 138bc75d-0d04-0410-961f-82ee72b054a4 | |
| 28 | unwind info for epilogues | |
| 29 | ||
| 30 | Curiously 4.4.x branch got later also fixed in this case by: | |
| 31 | commit 61db8bd232daeed3751b43570fab16146145e096 | |
| 32 | Author: jakub <jakub@138bc75d-0d04-0410-961f-82ee72b054a4> | |
| 33 | Date: Tue Jun 2 07:18:16 2009 +0000 | |
| 34 | git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-4_4-branch@148070 138bc75d-0d04-0410-961f-82ee72b054a4 | |
| 35 | (but that missed 4.4.0) | |
| 36 | ||
| 37 | As 4.5.0 was first FSF GCC with VTA I was trusting more the validity only | |
| 38 | after VTA and these heuristic results seems to confirm that. | |
| 39 | ||
| 40 | I find the change below definitely safe. | |
| 41 | ||
| 42 | Someone may object the original PR 12573 (do not try to skip prologue for -O2 | |
| 43 | -g code as it may cause more confusion than anything else) as while it fixed | |
| 44 | some GDB crashes there is no such purpose anymore with Tom's | |
| 45 | ambiguous-linespec patch. Still I believe PR 12573 was right to do. | |
| 46 | ||
| 47 | No regressions on {x86_64,x86_64-m32,i686}-fedora17-linux-gnu. | |
| 48 | ||
| 49 | I will check it in. | |
| 50 | ||
| 51 | ||
| 52 | Thanks, | |
| 53 | Jan | |
| 54 | ||
| 55 | ||
| 56 | gdb/ | |
| 57 | 2012-02-28 Jan Kratochvil <jan.kratochvil@redhat.com> | |
| 58 | ||
| 59 | PR symtab/13777 | |
| 60 | * dwarf2read.c (process_full_comp_unit): Set LOCATIONS_VALID only for | |
| 61 | GCC >=4.5. | |
| 62 | ||
| 63 | gdb/testsuite/ | |
| 64 | 2012-02-28 Jan Kratochvil <jan.kratochvil@redhat.com> | |
| 65 | ||
| 66 | PR symtab/13777 | |
| 67 | * gdb.dwarf2/dw2-skip-prologue.S (DW_AT_producer): Set it to 4.5.0. | |
| 68 | ||
| 69 | --- a/gdb/dwarf2read.c | |
| 70 | +++ b/gdb/dwarf2read.c | |
| 71 | @@ -4841,7 +4841,9 @@ process_full_comp_unit (struct dwarf2_per_cu_data *per_cu) | |
| 72 | ||
| 73 | /* GCC-4.0 has started to support -fvar-tracking. GCC-3.x still can | |
| 74 | produce DW_AT_location with location lists but it can be possibly | |
| 75 | - invalid without -fvar-tracking. | |
| 76 | + invalid without -fvar-tracking. Still up to GCC-4.4.x incl. 4.4.0 | |
| 77 | + there were bugs in prologue debug info, fixed later in GCC-4.5 | |
| 78 | + by "unwind info for epilogues" patch (which is not directly related). | |
| 79 | ||
| 80 | For -gdwarf-4 type units LOCATIONS_VALID indication is fortunately not | |
| 81 | needed, it would be wrong due to missing DW_AT_producer there. | |
| 82 | @@ -4849,7 +4851,7 @@ process_full_comp_unit (struct dwarf2_per_cu_data *per_cu) | |
| 83 | Still one can confuse GDB by using non-standard GCC compilation | |
| 84 | options - this waits on GCC PR other/32998 (-frecord-gcc-switches). | |
| 85 | */ | |
| 86 | - if (cu->has_loclist && gcc_4_minor >= 0) | |
| 87 | + if (cu->has_loclist && gcc_4_minor >= 5) | |
| 88 | symtab->locations_valid = 1; | |
| 89 | ||
| 90 | if (gcc_4_minor >= 5) | |
| 91 | --- a/gdb/testsuite/gdb.dwarf2/dw2-skip-prologue.S | |
| 92 | +++ b/gdb/testsuite/gdb.dwarf2/dw2-skip-prologue.S | |
| 93 | @@ -30,7 +30,7 @@ | |
| 94 | .4byte func_start /* DW_AT_low_pc */ | |
| 95 | .4byte func_end /* DW_AT_high_pc */ | |
| 96 | .ascii "main.c\0" /* DW_AT_name */ | |
| 97 | - .ascii "GNU C 4.0.0\0" /* DW_AT_producer must be >= 4.0 */ | |
| 98 | + .ascii "GNU C 4.5.0\0" /* DW_AT_producer must be >= 4.5 */ | |
| 99 | .byte 2 /* DW_AT_language (DW_LANG_C) */ | |
| 100 | ||
| 101 | .uleb128 2 /* Abbrev: DW_TAG_subprogram */ | |
| 102 |