On Mon, Jun 28, 2021 at 12:27 AM CHIGOT, CLEMENT
<clement.chi...@atos.net> wrote:
>
> A few things were missing to correctly handle DWARF files on AIX.
>
> Moreover, the previously base_addres was the starting address of
> the .text section of a loaded file instead of the difference
> between this starting address and the starting address in
> the file itself (unloaded).
>
> libbacktrace/ChangeLog:
> 2021-06-28 Clément Chigot <clement.chi...@atos.net>
>
> * xcoff.c (SSUBTYP_DWRNGES): New define.
> (xcoff_add): Use correct XCOFF DWARF section subtype
> for DEBUG_RANGES. Remove lineoff workaround.
> Adjust base_address.
> (xcoff_initialize_syminfo): Adapt to new base_address.
> (xcoff_lookup_pc): Likewise.
> (xcoff_initialize_fileline): Likewise.
Thanks. Committed as follows.
Ian
commit b5261d823243111ab733b2da25c50f361fe5de3f
Author: Ian Lance Taylor <i...@golang.org>
Date: Mon Jun 28 10:34:58 2021 -0700
libbacktrace: improve XCOFF support
libbacktrace/ChangeLog:
2021-06-28 Clément Chigot <clement.chi...@atos.net>
* xcoff.c (SSUBTYP_DWRNGES): New define.
(xcoff_add): Use correct XCOFF DWARF section subtype
for DEBUG_RANGES. Remove lineoff workaround.
Adjust base_address.
(xcoff_initialize_syminfo): Adapt to new base_address.
(xcoff_lookup_pc): Likewise.
(xcoff_initialize_fileline): Likewise.
diff --git a/libbacktrace/xcoff.c b/libbacktrace/xcoff.c
index 1e65c00553c..2ded8f0024f 100644
--- a/libbacktrace/xcoff.c
+++ b/libbacktrace/xcoff.c
@@ -133,6 +133,7 @@ typedef struct {
#define SSUBTYP_DWARNGE 0x50000 /* DWARF aranges section. */
#define SSUBTYP_DWABREV 0x60000 /* DWARF abbreviation section. */
#define SSUBTYP_DWSTR 0x70000 /* DWARF strings section. */
+#define SSUBTYP_DWRNGES 0x80000 /* DWARF ranges section. */
/* XCOFF symbol. */
@@ -586,7 +587,6 @@ xcoff_symname (const b_xcoff_syment *asym,
static int
xcoff_initialize_syminfo (struct backtrace_state *state,
uintptr_t base_address,
- const b_xcoff_scnhdr *sects,
const b_xcoff_syment *syms, size_t nsyms,
const unsigned char *strtab, size_t strtab_size,
backtrace_error_callback error_callback, void *data,
@@ -628,8 +628,7 @@ xcoff_initialize_syminfo (struct backtrace_state *state,
{
const b_xcoff_auxent *aux = (const b_xcoff_auxent *) (asym + 1);
xcoff_symbols[j].name = xcoff_symname (asym, strtab, strtab_size);
- xcoff_symbols[j].address = base_address + asym->n_value
- - sects[asym->n_scnum - 1].s_paddr;
+ xcoff_symbols[j].address = base_address + asym->n_value;
/* x_fsize will be 0 if there is no debug information. */
xcoff_symbols[j].size = aux->x_fcn.x_fsize;
++j;
@@ -767,7 +766,7 @@ xcoff_lookup_pc (struct backtrace_state *state
ATTRIBUTE_UNUSED,
lineno = (const b_xcoff_lineno *) lineptr;
if (lineno->l_lnno == 0)
break;
- if (pc <= fdata->base_address + lineno->l_addr.l_paddr - fn->sect_base)
+ if (pc <= fdata->base_address + lineno->l_addr.l_paddr)
break;
match = lnnoptr;
lnno = lineno->l_lnno;
@@ -1002,7 +1001,7 @@ xcoff_initialize_fileline (struct backtrace_state *state,
fn->name = xcoff_symname (fsym, strtab, strtab_size);
fn->filename = filename;
fn->sect_base = sects[fsym->n_scnum - 1].s_paddr;
- fn->pc = base_address + fsym->n_value - fn->sect_base;
+ fn->pc = base_address + fsym->n_value;
fn->size = fsize;
fn->lnno = lnno;
fn->lnnoptr = lnnoptr;
@@ -1153,8 +1152,16 @@ xcoff_add (struct backtrace_state *state, int
descriptor, off_t offset,
stext = §s[i];
- /* AIX ldinfo_textorg includes the XCOFF headers. */
- base_address = (exe ? XCOFF_AIX_TEXTBASE : base_address) + stext->s_scnptr;
+ /* base_address represents the difference between the
+ virtual memory address of the shared object or a loaded
+ executable and the offset of that object in the file
+ from which it was loaded.
+ On AIX, virtual address is either fixed for executable
+ or given by ldinfo. This address will include the XCOFF
+ headers. */
+ base_address = ((exe ? XCOFF_AIX_TEXTBASE : base_address)
+ + stext->s_scnptr
+ - stext->s_paddr);
lnnoptr = stext->s_lnnoptr;
nlnno = stext->s_nlnno;
@@ -1212,7 +1219,7 @@ xcoff_add (struct backtrace_state *state, int descriptor,
off_t offset,
if (sdata == NULL)
goto fail;
- if (!xcoff_initialize_syminfo (state, base_address, sects,
+ if (!xcoff_initialize_syminfo (state, base_address,
syms_view.data, fhdr.f_nsyms,
str_view.data, str_size,
error_callback, data, sdata))
@@ -1252,7 +1259,7 @@ xcoff_add (struct backtrace_state *state, int descriptor,
off_t offset,
case SSUBTYP_DWABREV:
idx = DEBUG_ABBREV;
break;
- case SSUBTYP_DWARNGE:
+ case SSUBTYP_DWRNGES:
idx = DEBUG_RANGES;
break;
case SSUBTYP_DWSTR:
@@ -1290,13 +1297,7 @@ xcoff_add (struct backtrace_state *state, int
descriptor, off_t offset,
dwarf_sections.data[DEBUG_INFO] = dwsect[DEBUG_INFO].data;
dwarf_sections.size[DEBUG_INFO] = dwsect[DEBUG_INFO].size;
-#if BACKTRACE_XCOFF_SIZE == 32
- /* XXX workaround for broken lineoff */
- dwarf_sections.data[DEBUG_LINE] = dwsect[DEBUG_LINE].data - 4;
-#else
- /* XXX workaround for broken lineoff */
- dwarf_sections.data[DEBUG_LINE] = dwsect[DEBUG_LINE].data - 12;
-#endif
+ dwarf_sections.data[DEBUG_LINE] = dwsect[DEBUG_LINE].data;
dwarf_sections.size[DEBUG_LINE] = dwsect[DEBUG_LINE].size;
dwarf_sections.data[DEBUG_ABBREV] = dwsect[DEBUG_ABBREV].data;
dwarf_sections.size[DEBUG_ABBREV] = dwsect[DEBUG_ABBREV].size;
@@ -1305,7 +1306,7 @@ xcoff_add (struct backtrace_state *state, int descriptor,
off_t offset,
dwarf_sections.data[DEBUG_STR] = dwsect[DEBUG_STR].data;
dwarf_sections.size[DEBUG_STR] = dwsect[DEBUG_STR].size;
- if (!backtrace_dwarf_add (state, 0, &dwarf_sections,
+ if (!backtrace_dwarf_add (state, base_address, &dwarf_sections,
1, /* big endian */
NULL, /* altlink */
error_callback, data, fileline_fn,
