libbacktrace: improve XCOFF support

libbacktrace/ChangeLog:
2021-06-28  Clément Chigot  <clement.chigot@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 1e65c00..2ded8f0 100644 (file)
--- 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 = &sects[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,