Re: RFC: printing pointers to global (data) variable on Windows...

[Joel Brobecker <brobecker@adacore.com>]

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> As mentioned on IRC, I just realize, now, the kind of project this is...
> So, I went with the other solution, which is to mark the minimal symbols
> from COFF/PE as size-less, and avoid the filtering in that case.
> Attached is a patch that does that.

Really attached, this time. Thanks, Tom.

-- 
Joel

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From 9ddc3d640a76b98814d6599327406f25535fe3bb Mon Sep 17 00:00:00 2001
From: Joel Brobecker <brobecker@adacore.com>
Date: Sat, 18 Aug 2012 00:32:08 +0200
Subject: [PATCH] WIP: Minimal symbols with no size info.

---
 gdb/coff-pe-read.c |    6 ++++--
 gdb/coffread.c     |    5 ++++-
 gdb/minsyms.c      |    7 ++++---
 gdb/minsyms.h      |   19 ++++++++++++-------
 gdb/printcmd.c     |    1 +
 gdb/symtab.h       |    4 ++++
 6 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/gdb/coff-pe-read.c b/gdb/coff-pe-read.c
index 66c7c82..070c8f7 100644
--- a/gdb/coff-pe-read.c
+++ b/gdb/coff-pe-read.c
@@ -108,6 +108,7 @@ add_pe_exported_sym (char *sym_name,
 
   char *qualified_name = 0;
   int dll_name_len = strlen (dll_name);
+  struct minimal_symbol *msym;
 
   /* Generate a (hopefully unique) qualified name using the first part
      of the dll name, e.g. KERNEL32!AddAtomA.  This matches the style
@@ -125,8 +126,9 @@ add_pe_exported_sym (char *sym_name,
   xfree (qualified_name);
 
   /* Enter the plain name as well, which might not be unique.  */
-  prim_record_minimal_symbol (sym_name, vma, 
-			      section_data->ms_type, objfile);
+  msym = prim_record_minimal_symbol (sym_name, vma,
+				     section_data->ms_type, objfile);
+  MSYMBOL_HAS_SIZE (msym) = 0;
 }
 
 /* Truncate a dll_name at the first dot character.  */
diff --git a/gdb/coffread.c b/gdb/coffread.c
index 0c7e6d9..ab8bd36 100644
--- a/gdb/coffread.c
+++ b/gdb/coffread.c
@@ -422,15 +422,18 @@ record_minimal_symbol (struct coff_symbol *cs, CORE_ADDR address,
 		       struct objfile *objfile)
 {
   struct bfd_section *bfd_section;
+  struct minimal_symbol *msym;
 
   /* We don't want TDESC entry points in the minimal symbol table.  */
   if (cs->c_name[0] == '@')
     return NULL;
 
   bfd_section = cs_to_bfd_section (cs, objfile);
-  return prim_record_minimal_symbol_and_info (cs->c_name, address,
+  msym = prim_record_minimal_symbol_and_info (cs->c_name, address,
 					      type, section,
 					      bfd_section, objfile);
+  MSYMBOL_HAS_SIZE (msym) = 0;
+  return msym;
 }
 \f
 /* coff_symfile_init ()
diff --git a/gdb/minsyms.c b/gdb/minsyms.c
index 1070fff..02b64ea 100644
--- a/gdb/minsyms.c
+++ b/gdb/minsyms.c
@@ -842,7 +842,7 @@ init_minimal_symbol_collection (void)
 
 /* See minsyms.h.  */
 
-void
+struct minimal_symbol *
 prim_record_minimal_symbol (const char *name, CORE_ADDR address,
 			    enum minimal_symbol_type ms_type,
 			    struct objfile *objfile)
@@ -869,8 +869,8 @@ prim_record_minimal_symbol (const char *name, CORE_ADDR address,
       section = -1;
     }
 
-  prim_record_minimal_symbol_and_info (name, address, ms_type,
-				       section, NULL, objfile);
+  return prim_record_minimal_symbol_and_info (name, address, ms_type,
+					      section, NULL, objfile);
 }
 
 /* See minsyms.h.  */
@@ -938,6 +938,7 @@ prim_record_minimal_symbol_full (const char *name, int name_len, int copy_name,
   MSYMBOL_TARGET_FLAG_1 (msymbol) = 0;
   MSYMBOL_TARGET_FLAG_2 (msymbol) = 0;
   MSYMBOL_SIZE (msymbol) = 0;
+  MSYMBOL_HAS_SIZE (msymbol) = 1; /* See this function's documentation.  */
 
   /* The hash pointers must be cleared! If they're not,
      add_minsym_to_hash_table will NOT add this msymbol to the hash table.  */
diff --git a/gdb/minsyms.h b/gdb/minsyms.h
index 8f0472f..76d7082 100644
--- a/gdb/minsyms.h
+++ b/gdb/minsyms.h
@@ -60,7 +60,14 @@ struct cleanup *make_cleanup_discard_minimal_symbols (void);
    though, to stash the pointer anywhere; as minimal symbols may be
    moved after creation.  The memory for the returned minimal symbol
    is still owned by the minsyms.c code, and should not be freed.
-   
+
+   By default, it is assumed that the symbol size can be determined,
+   which means that the "has_size" flag of the returned minimal symbol
+   is set to 1.  But some symbol table formats such as the one used
+   in COFF/PE, for instance, do not include that piece of information.
+   In that case, the "has_size" flag of the returned symbol should be
+   unset.
+
    Arguments are:
 
    NAME - the symbol's name
@@ -89,13 +96,11 @@ struct minimal_symbol *prim_record_minimal_symbol_full
    - uses strlen to compute NAME_LEN,
    - passes COPY_NAME = 0,
    - passes SECTION = 0,
-   - and passes BFD_SECTION = NULL.
-   
-   This variant does not return the new symbol.  */
+   - and passes BFD_SECTION = NULL.  */
 
-void prim_record_minimal_symbol (const char *, CORE_ADDR,
-				 enum minimal_symbol_type,
-				 struct objfile *);
+struct minimal_symbol *prim_record_minimal_symbol (const char *, CORE_ADDR,
+						   enum minimal_symbol_type,
+						   struct objfile *);
 
 /* Like prim_record_minimal_symbol_full, but:
    - uses strlen to compute NAME_LEN,
diff --git a/gdb/printcmd.c b/gdb/printcmd.c
index d5b5b63..9e8cd65 100644
--- a/gdb/printcmd.c
+++ b/gdb/printcmd.c
@@ -680,6 +680,7 @@ build_address_symbolic (struct gdbarch *gdbarch,
     }
 
   if (msymbol != NULL
+      && MSYMBOL_HAS_SIZE (msymbol)
       && MSYMBOL_SIZE (msymbol) == 0
       && MSYMBOL_TYPE (msymbol) != mst_text
       && MSYMBOL_TYPE (msymbol) != mst_text_gnu_ifunc
diff --git a/gdb/symtab.h b/gdb/symtab.h
index 76120a3..f45f498 100644
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -348,6 +348,9 @@ struct minimal_symbol
   unsigned int target_flag_1 : 1;
   unsigned int target_flag_2 : 1;
 
+  /* Should be zero if the size of the minimal symbol is not available.  */
+  unsigned int has_size : 1;
+
   /* Minimal symbols with the same hash key are kept on a linked
      list.  This is the link.  */
 
@@ -362,6 +365,7 @@ struct minimal_symbol
 #define MSYMBOL_TARGET_FLAG_1(msymbol)  (msymbol)->target_flag_1
 #define MSYMBOL_TARGET_FLAG_2(msymbol)  (msymbol)->target_flag_2
 #define MSYMBOL_SIZE(msymbol)		(msymbol)->size
+#define MSYMBOL_HAS_SIZE(msymbol)	(msymbol)->has_size
 #define MSYMBOL_TYPE(msymbol)		(msymbol)->type
 
 #include "minsyms.h"
-- 
1.7.1