libbacktrace: support FDPIC

Based on patch by Max Filippov.

	* internal.h: If FDPIC, #include <link.h> and/or <sys/link.h>.
	(libbacktrace_using_fdpic): Define.
	(struct libbacktrace_base_address): Define.
	(libbacktrace_add_base): Define.
	(backtrace_dwarf_add): Change base_address to struct
	libbacktrace_base_address.
	* dwarf.c (struct dwarf_data): Change base_address to struct
	libbacktrace_base_address.
	(add_ranges, find_address_ranges, build_ddress_map): Likewise.
	(build_dwarf_data, build_dwarf_add): Likewise.
	(add_low_high_range): Change base_address to struct
	libbacktrace_base_address.  Use libbacktrace_add_base.
	(add_ranges_from_ranges, add_ranges_from_rnglists): Likewise.
	(add_line): Use libbacktrace_add_base.
	* elf.c (elf_initialize_syminfo): Change base_address to struct
	libbacktrace_base_address.  Use libbacktrace_add_base.
	(elf_add): Change base_address to struct
	libbacktrace_base_address.
	(phdr_callback): Likewise.  Initialize base_address.m.
	(backtrace_initialize): If using FDPIC, don't call elf_add with
	main executable; always use dl_iterate_phdr.
	* macho.c (macho_add_symtab): Change base_address to struct
	libbacktrace_base_address.  Use libbacktrace_add_base.
	(macho_syminfo): Change base_address to struct
	libbacktrace_base_address.
	(macho_add_fat, macho_add_dsym, macho_add): Likewise.
	(backtrace_initialize): Likewise.  Initialize base_address.m.
	* pecoff.c (coff_initialize_syminfo): Change base_address to
	struct libbacktrace_base_address.  Use libbacktrace_add_base.
	(coff_add): Change base_address to struct
	libbacktrace_base_address.  Initialize base_address.m.

dwarf.c

@@ -722,8 +722,8 @@ struct dwarf_data
   struct dwarf_data *next;
   /* The data for .gnu_debugaltlink.  */
   struct dwarf_data *altlink;
-  /* The base address for this file.  */
-  uintptr_t base_address;
+  /* The base address mapping for this file.  */
+  struct libbacktrace_base_address base_address;
   /* A sorted list of address ranges.  */
   struct unit_addrs *addrs;
   /* Number of address ranges in list.  */
@@ -1944,8 +1944,9 @@ update_pcrange (const struct attr* attr, const struct attr_val* val,
 static int
 add_low_high_range (struct backtrace_state *state,
 		    const struct dwarf_sections *dwarf_sections,
-		    uintptr_t base_address, int is_bigendian,
-		    struct unit *u, const struct pcrange *pcrange,
+		    struct libbacktrace_base_address base_address,
+		    int is_bigendian, struct unit *u,
+		    const struct pcrange *pcrange,
 		    int (*add_range) (struct backtrace_state *state,
 				      void *rdata, uintptr_t lowpc,
 				      uintptr_t highpc,
@@ -1980,8 +1981,8 @@ add_low_high_range (struct backtrace_state *state,
 
   /* Add in the base address of the module when recording PC values,
      so that we can look up the PC directly.  */
-  lowpc += base_address;
-  highpc += base_address;
+  lowpc = libbacktrace_add_base (lowpc, base_address);
+  highpc = libbacktrace_add_base (highpc, base_address);
 
   return add_range (state, rdata, lowpc, highpc, error_callback, data, vec);
 }
@@ -1993,7 +1994,7 @@ static int
 add_ranges_from_ranges (
     struct backtrace_state *state,
     const struct dwarf_sections *dwarf_sections,
-    uintptr_t base_address, int is_bigendian,
+    struct libbacktrace_base_address base_address, int is_bigendian,
     struct unit *u, uintptr_t base,
     const struct pcrange *pcrange,
     int (*add_range) (struct backtrace_state *state, void *rdata,
@@ -2039,10 +2040,11 @@ add_ranges_from_ranges (
 	base = (uintptr_t) high;
       else
 	{
-	  if (!add_range (state, rdata,
-			  (uintptr_t) low + base + base_address,
-			  (uintptr_t) high + base + base_address,
-			  error_callback, data, vec))
+	  uintptr_t rl, rh;
+
+	  rl = libbacktrace_add_base ((uintptr_t) low + base, base_address);
+	  rh = libbacktrace_add_base ((uintptr_t) high + base, base_address);
+	  if (!add_range (state, rdata, rl, rh, error_callback, data, vec))
 	    return 0;
 	}
     }
@@ -2060,7 +2062,7 @@ static int
 add_ranges_from_rnglists (
     struct backtrace_state *state,
     const struct dwarf_sections *dwarf_sections,
-    uintptr_t base_address, int is_bigendian,
+    struct libbacktrace_base_address base_address, int is_bigendian,
     struct unit *u, uintptr_t base,
     const struct pcrange *pcrange,
     int (*add_range) (struct backtrace_state *state, void *rdata,
@@ -2143,9 +2145,10 @@ add_ranges_from_rnglists (
 				     u->addrsize, is_bigendian, index,
 				     error_callback, data, &high))
 	      return 0;
-	    if (!add_range (state, rdata, low + base_address,
-			    high + base_address, error_callback, data,
-			    vec))
+	    if (!add_range (state, rdata,
+			    libbacktrace_add_base (low, base_address),
+			    libbacktrace_add_base (high, base_address),
+			    error_callback, data, vec))
 	      return 0;
 	  }
 	  break;
@@ -2162,7 +2165,7 @@ add_ranges_from_rnglists (
 				     error_callback, data, &low))
 	      return 0;
 	    length = read_uleb128 (&rnglists_buf);
-	    low += base_address;
+	    low = libbacktrace_add_base (low, base_address);
 	    if (!add_range (state, rdata, low, low + length,
 			    error_callback, data, vec))
 	      return 0;
@@ -2176,8 +2179,9 @@ add_ranges_from_rnglists (
 
 	    low = read_uleb128 (&rnglists_buf);
 	    high = read_uleb128 (&rnglists_buf);
-	    if (!add_range (state, rdata, low + base + base_address,
-			    high + base + base_address,
+	    if (!add_range (state, rdata,
+			    libbacktrace_add_base (low + base, base_address),
+			    libbacktrace_add_base (high + base, base_address),
 			    error_callback, data, vec))
 	      return 0;
 	  }
@@ -2194,9 +2198,10 @@ add_ranges_from_rnglists (
 
 	    low = (uintptr_t) read_address (&rnglists_buf, u->addrsize);
 	    high = (uintptr_t) read_address (&rnglists_buf, u->addrsize);
-	    if (!add_range (state, rdata, low + base_address,
-			    high + base_address, error_callback, data,
-			    vec))
+	    if (!add_range (state, rdata,
+			    libbacktrace_add_base (low, base_address),
+			    libbacktrace_add_base (high, base_address),
+			    error_callback, data, vec))
 	      return 0;
 	  }
 	  break;
@@ -2208,7 +2213,7 @@ add_ranges_from_rnglists (
 
 	    low = (uintptr_t) read_address (&rnglists_buf, u->addrsize);
 	    length = (uintptr_t) read_uleb128 (&rnglists_buf);
-	    low += base_address;
+	    low = libbacktrace_add_base (low, base_address);
 	    if (!add_range (state, rdata, low, low + length,
 			    error_callback, data, vec))
 	      return 0;
@@ -2236,7 +2241,7 @@ add_ranges_from_rnglists (
 static int
 add_ranges (struct backtrace_state *state,
 	    const struct dwarf_sections *dwarf_sections,
-	    uintptr_t base_address, int is_bigendian,
+	    struct libbacktrace_base_address base_address, int is_bigendian,
 	    struct unit *u, uintptr_t base, const struct pcrange *pcrange,
 	    int (*add_range) (struct backtrace_state *state, void *rdata,
 			      uintptr_t lowpc, uintptr_t highpc,
@@ -2272,7 +2277,8 @@ add_ranges (struct backtrace_state *state,
    read, 0 if there is some error.  */
 
 static int
-find_address_ranges (struct backtrace_state *state, uintptr_t base_address,
+find_address_ranges (struct backtrace_state *state,
+		     struct libbacktrace_base_address base_address,
 		     struct dwarf_buf *unit_buf,
 		     const struct dwarf_sections *dwarf_sections,
 		     int is_bigendian, struct dwarf_data *altlink,
@@ -2427,7 +2433,8 @@ find_address_ranges (struct backtrace_state *state, uintptr_t base_address,
    on success, 0 on failure.  */
 
 static int
-build_address_map (struct backtrace_state *state, uintptr_t base_address,
+build_address_map (struct backtrace_state *state,
+		   struct libbacktrace_base_address base_address,
 		   const struct dwarf_sections *dwarf_sections,
 		   int is_bigendian, struct dwarf_data *altlink,
 		   backtrace_error_callback error_callback, void *data,
@@ -2646,7 +2653,7 @@ add_line (struct backtrace_state *state, struct dwarf_data *ddata,
 
   /* Add in the base address here, so that we can look up the PC
      directly.  */
-  ln->pc = pc + ddata->base_address;
+  ln->pc = libbacktrace_add_base (pc, ddata->base_address);
 
   ln->filename = filename;
   ln->lineno = lineno;
@@ -4285,7 +4292,7 @@ dwarf_fileline (struct backtrace_state *state, uintptr_t pc,
 
 static struct dwarf_data *
 build_dwarf_data (struct backtrace_state *state,
-		  uintptr_t base_address,
+		  struct libbacktrace_base_address base_address,
 		  const struct dwarf_sections *dwarf_sections,
 		  int is_bigendian,
 		  struct dwarf_data *altlink,
@@ -4343,7 +4350,7 @@ build_dwarf_data (struct backtrace_state *state,
 
 int
 backtrace_dwarf_add (struct backtrace_state *state,
-		     uintptr_t base_address,
+		     struct libbacktrace_base_address base_address,
 		     const struct dwarf_sections *dwarf_sections,
 		     int is_bigendian,
 		     struct dwarf_data *fileline_altlink,

elf.c

@@ -633,7 +633,7 @@ elf_symbol_search (const void *vkey, const void *ventry)
 
 static int
 elf_initialize_syminfo (struct backtrace_state *state,
-			uintptr_t base_address,
+			struct libbacktrace_base_address base_address,
 			const unsigned char *symtab_data, size_t symtab_size,
 			const unsigned char *strtab, size_t strtab_size,
 			backtrace_error_callback error_callback,
@@ -699,7 +699,8 @@ elf_initialize_syminfo (struct backtrace_state *state,
 	  = *(const b_elf_addr *) (opd->data + (sym->st_value - opd->addr));
       else
 	elf_symbols[j].address = sym->st_value;
-      elf_symbols[j].address += base_address;
+      elf_symbols[j].address =
+	libbacktrace_add_base (elf_symbols[j].address, base_address);
       elf_symbols[j].size = sym->st_size;
       ++j;
     }
@@ -6499,7 +6500,8 @@ backtrace_uncompress_lzma (struct backtrace_state *state,
 static int
 elf_add (struct backtrace_state *state, const char *filename, int descriptor,
 	 const unsigned char *memory, size_t memory_size,
-	 uintptr_t base_address, struct elf_ppc64_opd_data *caller_opd,
+	 struct libbacktrace_base_address base_address,
+	 struct elf_ppc64_opd_data *caller_opd,
 	 backtrace_error_callback error_callback, void *data,
 	 fileline *fileline_fn, int *found_sym, int *found_dwarf,
 	 struct dwarf_data **fileline_entry, int exe, int debuginfo,
@@ -7349,6 +7351,7 @@ phdr_callback (struct dl_phdr_info *info, size_t size ATTRIBUTE_UNUSED,
   const char *filename;
   int descriptor;
   int does_not_exist;
+  struct libbacktrace_base_address base_address;
   fileline elf_fileline_fn;
   int found_dwarf;
 
@@ -7378,7 +7381,8 @@ phdr_callback (struct dl_phdr_info *info, size_t size ATTRIBUTE_UNUSED,
 	return 0;
     }
 
-  if (elf_add (pd->state, filename, descriptor, NULL, 0, info->dlpi_addr, NULL,
+  base_address.m = info->dlpi_addr;
+  if (elf_add (pd->state, filename, descriptor, NULL, 0, base_address, NULL,
 	       pd->error_callback, pd->data, &elf_fileline_fn, pd->found_sym,
 	       &found_dwarf, NULL, 0, 0, NULL, 0))
     {
@@ -7407,11 +7411,20 @@ backtrace_initialize (struct backtrace_state *state, const char *filename,
   fileline elf_fileline_fn = elf_nodebug;
   struct phdr_data pd;
 
-  ret = elf_add (state, filename, descriptor, NULL, 0, 0, NULL, error_callback,
-		 data, &elf_fileline_fn, &found_sym, &found_dwarf, NULL, 1, 0,
-		 NULL, 0);
-  if (!ret)
-    return 0;
+  /* When using fdpic we must use dl_iterate_phdr for all modules, including
+     the main executable, so that we can get the right base address
+     mapping.  */
+  if (!libbacktrace_using_fdpic ())
+    {
+      struct libbacktrace_base_address zero_base_address;
+
+      memset (&zero_base_address, 0, sizeof zero_base_address);
+      ret = elf_add (state, filename, descriptor, NULL, 0, zero_base_address,
+		     NULL, error_callback, data, &elf_fileline_fn, &found_sym,
+		     &found_dwarf, NULL, 1, 0, NULL, 0);
+      if (!ret)
+	return 0;
+    }
 
   pd.state = state;
   pd.error_callback = error_callback;

internal.h

@@ -323,10 +323,44 @@ struct dwarf_sections
 
 struct dwarf_data;
 
+/* The load address mapping.  */
+
+#if defined(__FDPIC__) && defined(HAVE_DL_ITERATE_PHDR) && (defined(HAVE_LINK_H) || defined(HAVE_SYS_LINK_H))
+
+#ifdef HAVE_LINK_H
+ #include <link.h>
+#endif
+#ifdef HAVE_SYS_LINK_H
+ #include <sys/link.h>
+#endif
+
+#define libbacktrace_using_fdpic() (1)
+
+struct libbacktrace_base_address
+{
+  struct elf32_fdpic_loadaddr m;
+};
+
+#define libbacktrace_add_base(pc, base) \
+  ((uintptr_t) (__RELOC_POINTER ((pc), (base).m)))
+
+#else /* not _FDPIC__ */
+
+#define libbacktrace_using_fdpic() (0)
+
+struct libbacktrace_base_address
+{
+  uintptr_t m;
+};
+
+#define libbacktrace_add_base(pc, base) ((pc) + (base).m)
+
+#endif /* not _FDPIC__ */
+
 /* Add file/line information for a DWARF module.  */
 
 extern int backtrace_dwarf_add (struct backtrace_state *state,
-				uintptr_t base_address,
+				struct libbacktrace_base_address base_address,
 				const struct dwarf_sections *dwarf_sections,
 				int is_bigendian,
 				struct dwarf_data *fileline_altlink,

macho.c

@@ -315,8 +315,9 @@ static const char * const dwarf_section_names[DEBUG_MAX] =
 /* Forward declaration.  */
 
 static int macho_add (struct backtrace_state *, const char *, int, off_t,
-		      const unsigned char *, uintptr_t, int,
-		      backtrace_error_callback, void *, fileline *, int *);
+		      const unsigned char *, struct libbacktrace_base_address,
+		      int, backtrace_error_callback, void *, fileline *,
+		      int *);
 
 /* A dummy callback function used when we can't find any debug info.  */
 
@@ -511,7 +512,7 @@ macho_defined_symbol (uint8_t type)
 
 static int
 macho_add_symtab (struct backtrace_state *state, int descriptor,
-		  uintptr_t base_address, int is_64,
+		  struct libbacktrace_base_address base_address, int is_64,
 		  off_t symoff, unsigned int nsyms, off_t stroff,
 		  unsigned int strsize,
 		  backtrace_error_callback error_callback, void *data)
@@ -626,7 +627,7 @@ macho_add_symtab (struct backtrace_state *state, int descriptor,
       if (name[0] == '_')
 	++name;
       macho_symbols[j].name = name;
-      macho_symbols[j].address = value + base_address;
+      macho_symbols[j].address = libbacktrace_add_base (value, base_address);
       ++j;
     }
 
@@ -758,7 +759,8 @@ macho_syminfo (struct backtrace_state *state, uintptr_t addr,
 static int
 macho_add_fat (struct backtrace_state *state, const char *filename,
 	       int descriptor, int swapped, off_t offset,
-	       const unsigned char *match_uuid, uintptr_t base_address,
+	       const unsigned char *match_uuid,
+	       struct libbacktrace_base_address base_address,
 	       int skip_symtab, uint32_t nfat_arch, int is_64,
 	       backtrace_error_callback error_callback, void *data,
 	       fileline *fileline_fn, int *found_sym)
@@ -860,7 +862,8 @@ macho_add_fat (struct backtrace_state *state, const char *filename,
 
 static int
 macho_add_dsym (struct backtrace_state *state, const char *filename,
-		uintptr_t base_address, const unsigned char *uuid,
+		struct libbacktrace_base_address base_address,
+		const unsigned char *uuid,
 		backtrace_error_callback error_callback, void *data,
 		fileline* fileline_fn)
 {
@@ -978,7 +981,7 @@ macho_add_dsym (struct backtrace_state *state, const char *filename,
 static int
 macho_add (struct backtrace_state *state, const char *filename, int descriptor,
 	   off_t offset, const unsigned char *match_uuid,
-	   uintptr_t base_address, int skip_symtab,
+	   struct libbacktrace_base_address base_address, int skip_symtab,
 	   backtrace_error_callback error_callback, void *data,
 	   fileline *fileline_fn, int *found_sym)
 {
@@ -1240,7 +1243,7 @@ backtrace_initialize (struct backtrace_state *state, const char *filename,
   c = _dyld_image_count ();
   for (i = 0; i < c; ++i)
     {
-      uintptr_t base_address;
+      struct libbacktrace_base_address base_address;
       const char *name;
       int d;
       fileline mff;
@@ -1264,7 +1267,7 @@ backtrace_initialize (struct backtrace_state *state, const char *filename,
 	    continue;
 	}
 
-      base_address = _dyld_get_image_vmaddr_slide (i);
+      base_address.m = _dyld_get_image_vmaddr_slide (i);
 
       mff = macho_nodebug;
       if (!macho_add (state, name, d, 0, NULL, base_address, 0,
@@ -1319,10 +1322,12 @@ backtrace_initialize (struct backtrace_state *state, const char *filename,
 		      void *data, fileline *fileline_fn)
 {
   fileline macho_fileline_fn;
+  struct libbacktrace_base_address zero_base_address;
   int found_sym;
 
   macho_fileline_fn = macho_nodebug;
-  if (!macho_add (state, filename, descriptor, 0, NULL, 0, 0,
+  memset (&zero_base_address, 0, sizeof zero_base_address);
+  if (!macho_add (state, filename, descriptor, 0, NULL, zero_base_address, 0,
 		  error_callback, data, &macho_fileline_fn, &found_sym))
     return 0;