Re: combine bfd_lookup_symbol in solib-*.c

[Yao Qi <yao@codesourcery.com>]

[-- Attachment #1: Type: text/plain, Size: 1749 bytes --]

On 08/29/2011 07:41 PM, Pedro Alves wrote:

> On Thursday 18 August 2011 16:36:46, Yao Qi wrote:
>
>> +
>> +CORE_ADDR
>> +bfd_lookup_symbol (bfd *abfd, const char *symname,
>> +                  int (*is_right_sym) (asymbol *, const char *))
>
> All the function does with the passed in SYMNAME is passing
> it down to the callback.  If the interface has been generalized to
> pass in a "match" callback, then make the symname parameter
> generic too, like:
>
>    CORE_ADDR
>    bfd_lookup_symbol (bfd *abfd,
>                    int (*is_right_sym) (asymbol *, void *),
>                    void *data);
>
> Please document the parameters.

OK, parameters are documented.

>
> I think it's best to reserve extern symbols that start with
> "bfd_" to libbfd proper.  Maybe gdb_bfd_lookup_symbol would
> be a good enough alternative.  (Or maybe propose the function
> for bfd proper, though I'd suggest fixing its interface
> to not assume 0 return is error then)
>

I agree.  Renamed bfd_* functions to gdb_bfd_*.

>> +/* Lookup the value for a specific symbol.
>> +
>> +   An expensive way to lookup the value of a single symbol for
>> +   bfd's that are only temporary anyway.  This is used by the
>> +   shared library support to find the address of the debugger
>> +   notification routine in the shared library.
>> +
>> +   The returned symbol may be in a code or data section; functions
>> +   will normally be in a code section, but may be in a data section
>> +   if this architecture uses function descriptors.
>
> The way you've generalized the function, since it's the
> callback's responsibility to pick the the symbol, this
> comment no longer appears to be in the right place.
>

OK, removed this comment here.

-- 
Yao (齐尧)

[-- Attachment #2: 0001-combine-bfd_lookup_symbol.patch --]
[-- Type: text/x-patch, Size: 16798 bytes --]

        gdb/
        * solib-dsbt.c (bfd_lookup_symbol): Removed.
        (cmp_name): New.
        (enable_break2): Update caller.
        * solib-frv.c (bfd_lookup_symbol): Removed.
        (cmp_name): New.
        (enable_break2): Update caller.
        * solib-pa64.c (bfd_lookup_symbol): Removed.
        (cmp_name): New.
        * solib-svr4.c (bfd_lookup_symbol): Removed.
        (cmp_name_and_sec_flags): New.
        (enable_break): Update caller.
        * solib.c (gdb_bfd_lookup_symbol_from_symtab): New.
        (gdb_bfd_lookup_symbol_from_dyn_symtab): New.
        (gdb_bfd_lookup_symbol): New.
        * solib.h: Functions declarations.
---
 gdb/solib-dsbt.c |   80 +++++---------------------------------------
 gdb/solib-frv.c  |   82 +++++----------------------------------------
 gdb/solib-pa64.c |   48 +++-----------------------
 gdb/solib-svr4.c |   91 +++++---------------------------------------------
 gdb/solib.c      |   97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 gdb/solib.h      |   14 ++++++++
 6 files changed, 146 insertions(+), 266 deletions(-)

diff --git a/gdb/solib-dsbt.c b/gdb/solib-dsbt.c
index 2569395..1db4537 100644
--- a/gdb/solib-dsbt.c
+++ b/gdb/solib-dsbt.c
@@ -508,76 +508,6 @@ scan_dyntag (int dyntag, bfd *abfd, CORE_ADDR *ptr)
   return 0;
 }
 
-/* An expensive way to lookup the value of a single symbol for
-   bfd's that are only temporary anyway.  This is used by the
-   shared library support to find the address of the debugger
-   interface structures in the shared library.
-
-   Note that 0 is specifically allowed as an error return (no
-   such symbol).  */
-
-static CORE_ADDR
-bfd_lookup_symbol (bfd *abfd, char *symname)
-{
-  long storage_needed;
-  asymbol *sym;
-  asymbol **symbol_table;
-  unsigned int number_of_symbols;
-  unsigned int i;
-  struct cleanup *back_to;
-  CORE_ADDR symaddr = 0;
-
-  storage_needed = bfd_get_symtab_upper_bound (abfd);
-
-  if (storage_needed > 0)
-    {
-      symbol_table = (asymbol **) xmalloc (storage_needed);
-      back_to = make_cleanup (xfree, symbol_table);
-      number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
-
-      for (i = 0; i < number_of_symbols; i++)
-	{
-	  sym = *symbol_table++;
-	  if (strcmp (sym->name, symname) == 0)
-	    {
-	      /* Bfd symbols are section relative. */
-	      symaddr = sym->value + sym->section->vma;
-	      break;
-	    }
-	}
-      do_cleanups (back_to);
-    }
-
-  if (symaddr)
-    return symaddr;
-
-  /* Look for the symbol in the dynamic string table too.  */
-
-  storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd);
-
-  if (storage_needed > 0)
-    {
-      symbol_table = (asymbol **) xmalloc (storage_needed);
-      back_to = make_cleanup (xfree, symbol_table);
-      number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd, symbol_table);
-
-      for (i = 0; i < number_of_symbols; i++)
-	{
-	  sym = *symbol_table++;
-	  if (strcmp (sym->name, symname) == 0)
-	    {
-	      /* Bfd symbols are section relative. */
-	      symaddr = sym->value + sym->section->vma;
-	      break;
-	    }
-	}
-      do_cleanups (back_to);
-    }
-
-  return symaddr;
-}
-
-
 /* If no open symbol file, attempt to locate and open the main symbol
    file.
 
@@ -852,6 +782,14 @@ enable_break_failure_warning (void)
 	   "and track explicitly loaded dynamic code."));
 }
 
+/* Helper function for gdb_bfd_lookup_symbol.  */
+
+static int
+cmp_name (asymbol *sym, const void *data)
+{
+  return (strcmp (sym->name, (const char *) data) == 0);
+}
+
 /* The dynamic linkers has, as part of its debugger interface, support
    for arranging for the inferior to hit a breakpoint after mapping in
    the shared libraries.  This function enables that breakpoint.
@@ -957,7 +895,7 @@ enable_break2 (void)
 	    info->interp_plt_sect_low + bfd_section_size (tmp_bfd, interp_sect);
 	}
 
-      addr = bfd_lookup_symbol (tmp_bfd, "_dl_debug_addr");
+      addr = gdb_bfd_lookup_symbol (tmp_bfd, cmp_name, "_dl_debug_addr");
       if (addr == 0)
 	{
 	  warning (_("Could not find symbol _dl_debug_addr in dynamic linker"));
diff --git a/gdb/solib-frv.c b/gdb/solib-frv.c
index e1c16d9..c70dffb 100644
--- a/gdb/solib-frv.c
+++ b/gdb/solib-frv.c
@@ -239,77 +239,6 @@ static void frv_relocate_main_executable (void);
 static CORE_ADDR main_got (void);
 static int enable_break2 (void);
 
-/* Lookup the value for a specific symbol.
-
-   An expensive way to lookup the value of a single symbol for
-   bfd's that are only temporary anyway.  This is used by the
-   shared library support to find the address of the debugger
-   interface structures in the shared library.
-
-   Note that 0 is specifically allowed as an error return (no
-   such symbol).  */
-
-static CORE_ADDR
-bfd_lookup_symbol (bfd *abfd, char *symname)
-{
-  long storage_needed;
-  asymbol *sym;
-  asymbol **symbol_table;
-  unsigned int number_of_symbols;
-  unsigned int i;
-  struct cleanup *back_to;
-  CORE_ADDR symaddr = 0;
-
-  storage_needed = bfd_get_symtab_upper_bound (abfd);
-
-  if (storage_needed > 0)
-    {
-      symbol_table = (asymbol **) xmalloc (storage_needed);
-      back_to = make_cleanup (xfree, symbol_table);
-      number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
-
-      for (i = 0; i < number_of_symbols; i++)
-	{
-	  sym = *symbol_table++;
-	  if (strcmp (sym->name, symname) == 0)
-	    {
-	      /* Bfd symbols are section relative.  */
-	      symaddr = sym->value + sym->section->vma;
-	      break;
-	    }
-	}
-      do_cleanups (back_to);
-    }
-
-  if (symaddr)
-    return symaddr;
-
-  /* Look for the symbol in the dynamic string table too.  */
-
-  storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd);
-
-  if (storage_needed > 0)
-    {
-      symbol_table = (asymbol **) xmalloc (storage_needed);
-      back_to = make_cleanup (xfree, symbol_table);
-      number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd, symbol_table);
-
-      for (i = 0; i < number_of_symbols; i++)
-	{
-	  sym = *symbol_table++;
-	  if (strcmp (sym->name, symname) == 0)
-	    {
-	      /* Bfd symbols are section relative.  */
-	      symaddr = sym->value + sym->section->vma;
-	      break;
-	    }
-	}
-      do_cleanups (back_to);
-    }
-
-  return symaddr;
-}
-
 /* Implement the "open_symbol_file_object" target_so_ops method.  */
 
 static int
@@ -554,6 +483,14 @@ enable_break_failure_warning (void)
 	   "and track explicitly loaded dynamic code."));
 }
 
+/* Helper function for gdb_bfd_lookup_symbol.  */
+
+static int
+cmp_name (asymbol *sym, const void *data)
+{
+  return (strcmp (sym->name, (const char *) data) == 0);
+}
+
 /* Arrange for dynamic linker to hit breakpoint.
 
    The dynamic linkers has, as part of its debugger interface, support
@@ -680,7 +617,8 @@ enable_break2 (void)
 	    interp_plt_sect_low + bfd_section_size (tmp_bfd, interp_sect);
 	}
 
-      addr = bfd_lookup_symbol (tmp_bfd, "_dl_debug_addr");
+      addr = gdb_bfd_lookup_symbol (tmp_bfd, cmp_name, "_dl_debug_addr");
+
       if (addr == 0)
 	{
 	  warning (_("Could not find symbol _dl_debug_addr "
diff --git a/gdb/solib-pa64.c b/gdb/solib-pa64.c
index cd38728..dae99ba 100644
--- a/gdb/solib-pa64.c
+++ b/gdb/solib-pa64.c
@@ -269,51 +269,14 @@ read_dynamic_info (asection *dyninfo_sect, dld_cache_t *dld_cache_p)
   return 1;
 }
 
-/* bfd_lookup_symbol -- lookup the value for a specific symbol
+/* Helper function for gdb_bfd_lookup_symbol_from_symtab.  */
 
-   An expensive way to lookup the value of a single symbol for
-   bfd's that are only temporary anyway.  This is used by the
-   shared library support to find the address of the debugger
-   interface structures in the shared library.
-
-   Note that 0 is specifically allowed as an error return (no
-   such symbol).  */
-
-static CORE_ADDR
-bfd_lookup_symbol (bfd *abfd, char *symname)
+static int
+cmp_name (asymbol *sym, const void *data)
 {
-  unsigned int storage_needed;
-  asymbol *sym;
-  asymbol **symbol_table;
-  unsigned int number_of_symbols;
-  unsigned int i;
-  struct cleanup *back_to;
-  CORE_ADDR symaddr = 0;
-
-  storage_needed = bfd_get_symtab_upper_bound (abfd);
-
-  if (storage_needed > 0)
-    {
-      symbol_table = (asymbol **) xmalloc (storage_needed);
-      back_to = make_cleanup (xfree, symbol_table);
-      number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
-
-      for (i = 0; i < number_of_symbols; i++)
-	{
-	  sym = *symbol_table++;
-	  if (strcmp (sym->name, symname) == 0)
-	    {
-	      /* Bfd symbols are section relative.  */
-	      symaddr = sym->value + sym->section->vma;
-	      break;
-	    }
-	}
-      do_cleanups (back_to);
-    }
-  return (symaddr);
+  return (strcmp (sym->name, (const char *) data) == 0);
 }
 
-
 /* This hook gets called just before the first instruction in the
    inferior process is executed.
 
@@ -421,7 +384,8 @@ manpage for methods to privately map shared library text."));
 	 routine.  */
       load_addr = regcache_read_pc (get_current_regcache ())
 		  - tmp_bfd->start_address;
-      sym_addr = bfd_lookup_symbol (tmp_bfd, "__dld_break");
+      sym_addr = bfd_lookup_symbol_from_symtab (tmp_bfd, cmp_name,
+						"__dld_break");
       sym_addr = load_addr + sym_addr + 4;
       
       /* Create the shared library breakpoint.  */
diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c
index f643a24..13cad46 100644
--- a/gdb/solib-svr4.c
+++ b/gdb/solib-svr4.c
@@ -370,86 +370,6 @@ get_svr4_info (void)
 
 static int match_main (const char *);
 
-/* Lookup the value for a specific symbol.
-
-   An expensive way to lookup the value of a single symbol for
-   bfd's that are only temporary anyway.  This is used by the
-   shared library support to find the address of the debugger
-   notification routine in the shared library.
-
-   The returned symbol may be in a code or data section; functions
-   will normally be in a code section, but may be in a data section
-   if this architecture uses function descriptors.
-
-   Note that 0 is specifically allowed as an error return (no
-   such symbol).  */
-
-static CORE_ADDR
-bfd_lookup_symbol (bfd *abfd, const char *symname)
-{
-  long storage_needed;
-  asymbol *sym;
-  asymbol **symbol_table;
-  unsigned int number_of_symbols;
-  unsigned int i;
-  struct cleanup *back_to;
-  CORE_ADDR symaddr = 0;
-
-  storage_needed = bfd_get_symtab_upper_bound (abfd);
-
-  if (storage_needed > 0)
-    {
-      symbol_table = (asymbol **) xmalloc (storage_needed);
-      back_to = make_cleanup (xfree, symbol_table);
-      number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
-
-      for (i = 0; i < number_of_symbols; i++)
-	{
-	  sym = *symbol_table++;
-	  if (strcmp (sym->name, symname) == 0
-              && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0)
-	    {
-	      /* BFD symbols are section relative.  */
-	      symaddr = sym->value + sym->section->vma;
-	      break;
-	    }
-	}
-      do_cleanups (back_to);
-    }
-
-  if (symaddr)
-    return symaddr;
-
-  /* On FreeBSD, the dynamic linker is stripped by default.  So we'll
-     have to check the dynamic string table too.  */
-
-  storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd);
-
-  if (storage_needed > 0)
-    {
-      symbol_table = (asymbol **) xmalloc (storage_needed);
-      back_to = make_cleanup (xfree, symbol_table);
-      number_of_symbols = bfd_canonicalize_dynamic_symtab (abfd, symbol_table);
-
-      for (i = 0; i < number_of_symbols; i++)
-	{
-	  sym = *symbol_table++;
-
-	  if (strcmp (sym->name, symname) == 0
-              && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0)
-	    {
-	      /* BFD symbols are section relative.  */
-	      symaddr = sym->value + sym->section->vma;
-	      break;
-	    }
-	}
-      do_cleanups (back_to);
-    }
-
-  return symaddr;
-}
-
-
 /* Read program header TYPE from inferior memory.  The header is found
    by scanning the OS auxillary vector.
 
@@ -1253,6 +1173,14 @@ exec_entry_point (struct bfd *abfd, struct target_ops *targ)
 					     targ);
 }
 
+/* Helper function for gdb_bfd_lookup_symbol.  */
+
+static int
+cmp_name_and_sec_flags (asymbol *sym, const void *data)
+{
+  return (strcmp (sym->name, (const char *) data) == 0
+	  && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0);
+}
 /* Arrange for dynamic linker to hit breakpoint.
 
    Both the SunOS and the SVR4 dynamic linkers have, as part of their
@@ -1501,7 +1429,8 @@ enable_break (struct svr4_info *info, int from_tty)
       /* Now try to set a breakpoint in the dynamic linker.  */
       for (bkpt_namep = solib_break_names; *bkpt_namep != NULL; bkpt_namep++)
 	{
-	  sym_addr = bfd_lookup_symbol (tmp_bfd, *bkpt_namep);
+	  sym_addr = gdb_bfd_lookup_symbol (tmp_bfd, cmp_name_and_sec_flags,
+					    (const void *) *bkpt_namep);
 	  if (sym_addr != 0)
 	    break;
 	}
diff --git a/gdb/solib.c b/gdb/solib.c
index f843723..2c0548e 100644
--- a/gdb/solib.c
+++ b/gdb/solib.c
@@ -1336,6 +1336,103 @@ solib_global_lookup (const struct objfile *objfile,
   return NULL;
 }
 
+/* Lookup the value for a specific symbol from dynamic symbol table.  Look
+   up symbol from ABFD.  MATCH_SYM is a callback function to determine
+   whether to pick up a symbol.  DATA is the input of this callback
+   function.  Return NULL if symbol is not found.  */
+
+CORE_ADDR
+gdb_bfd_lookup_symbol_from_symtab (bfd *abfd,
+				   int (*match_sym) (asymbol *, const void *),
+				   const void *data)
+{
+  long storage_needed = bfd_get_symtab_upper_bound (abfd);
+  CORE_ADDR symaddr = 0;
+
+  if (storage_needed > 0)
+    {
+      unsigned int i;
+
+      asymbol **symbol_table = (asymbol **) xmalloc (storage_needed);
+      struct cleanup *back_to = make_cleanup (xfree, symbol_table);
+      unsigned int number_of_symbols =
+	bfd_canonicalize_symtab (abfd, symbol_table);
+
+      for (i = 0; i < number_of_symbols; i++)
+	{
+	  asymbol *sym  = *symbol_table++;
+
+	  if (match_sym (sym, data))
+	    {
+	      /* BFD symbols are section relative.  */
+	      symaddr = sym->value + sym->section->vma;
+	      break;
+	    }
+	}
+      do_cleanups (back_to);
+    }
+
+  return symaddr;
+}
+
+/* Lookup the value for a specific symbol from symbol table.  Look up symbol
+   from ABFD.  MATCH_SYM is a callback function to determine whether to pick
+   up a symbol.  DATA is the input of this callback function.  Return NULL
+   if symbol is not found.  */
+
+static CORE_ADDR
+bfd_lookup_symbol_from_dyn_symtab (bfd *abfd,
+				   int (*match_sym) (asymbol *,
+							const void *),
+				   const void *data)
+{
+  long storage_needed = bfd_get_dynamic_symtab_upper_bound (abfd);
+  CORE_ADDR symaddr = 0;
+
+  if (storage_needed > 0)
+    {
+      unsigned int i;
+      asymbol **symbol_table = (asymbol **) xmalloc (storage_needed);
+      struct cleanup *back_to = make_cleanup (xfree, symbol_table);
+      unsigned int number_of_symbols =
+	bfd_canonicalize_dynamic_symtab (abfd, symbol_table);
+
+      for (i = 0; i < number_of_symbols; i++)
+	{
+	  asymbol *sym = *symbol_table++;
+
+	  if (match_sym (sym, data))
+	    {
+	      /* BFD symbols are section relative.  */
+	      symaddr = sym->value + sym->section->vma;
+	      break;
+	    }
+	}
+      do_cleanups (back_to);
+    }
+  return symaddr;
+}
+
+/* Lookup the value for a specific symbol from symbol table and dynamic
+   symbol table.  Look up symbol from ABFD.  MATCH_SYM is a callback
+   function to determine whether to pick up a symbol.  DATA is the
+   input of this callback function.  Return NULL if symbol is not
+   found.  */
+
+CORE_ADDR
+gdb_bfd_lookup_symbol (bfd *abfd,
+		       int (*match_sym) (asymbol *, const void *),
+		       const void *data)
+{
+  CORE_ADDR symaddr = gdb_bfd_lookup_symbol_from_symtab (abfd, match_sym, data);
+
+  /* On FreeBSD, the dynamic linker is stripped by default.  So we'll
+     have to check the dynamic string table too.  */
+  if (symaddr == 0)
+    symaddr = bfd_lookup_symbol_from_dyn_symtab (abfd, match_sym, data);
+
+  return symaddr;
+}
 
 extern initialize_file_ftype _initialize_solib; /* -Wmissing-prototypes */
 
diff --git a/gdb/solib.h b/gdb/solib.h
index c473d85..54640b2 100644
--- a/gdb/solib.h
+++ b/gdb/solib.h
@@ -78,4 +78,18 @@ extern void set_solib_ops (struct gdbarch *gdbarch,
 
 extern int libpthread_name_p (const char *name);
 
+/* Look up symbol from both symbol table and dynamic string table.  */
+
+extern CORE_ADDR gdb_bfd_lookup_symbol (bfd *abfd,
+					int (*match_sym) (asymbol *,
+							  const void *),
+					const void *data);
+
+/* Look up symbol from symbol table.  */
+
+extern CORE_ADDR bfd_lookup_symbol_from_symtab (bfd *abfd,
+						int (*match_sym) (asymbol *,
+								  const void *),
+						const void *data);
+
 #endif /* SOLIB_H */
-- 
1.7.0.4