Re: [PATCH] Fix up msymbol type of dll trampoline to mst_solib_trampoline

[Yao Qi <yao@codesourcery.com>]

On 06/28/2013 11:43 PM, Tom Tromey wrote:
> It seems to me that it would be more efficient to keep a hash table of
> minsyms under construction, and then do this lookup when entering a new
> minsym.  This would avoid repeated loops over all minsyms being defined.
> 
> That is, if the new symbol is _imp_x, look up x.  If the symbol is x,
> look up _imp_x.  Then modify a symbol if needed.

In the updated patch, I use hash table when looking for up minsyms, but
in a little different way.  After currently constructing minsyms are
installed to OBJFILE, there is a hash table built, we can use that one,
instead of maintaining a separate one.  That is, after the hash table
of minsyms of OBJFILE is built up, we can iterate all minsyms, if
symbol is _imp_x, look up x in the hash table.  If found, modify the
found's type.

Regression tested on i686-pc-mingw32.  The following fail is fixed.

 FAIL: gdb.base/solib-symbol.exp: foo in libmd

-- 
Yao (齐尧)

gdb:

2013-07-03  Yao Qi  <yao@codesourcery.com>

	* coffread.c (coff_symfile_read): Iterate over minimal symbols,
	if the name is prefixed by "__imp_" or "_imp_", look for minimal
	symbol without prefix.  If found, set its type to
	'mst_solib_trampoline'.
---
 gdb/coffread.c |   30 ++++++++++++++++++++++++++++++
 1 files changed, 30 insertions(+), 0 deletions(-)

diff --git a/gdb/coffread.c b/gdb/coffread.c
index bf39085..f9bb59f 100644
--- a/gdb/coffread.c
+++ b/gdb/coffread.c
@@ -650,6 +650,36 @@ coff_symfile_read (struct objfile *objfile, int symfile_flags)
 
   install_minimal_symbols (objfile);
 
+  if (pe_file)
+    {
+      int i;
+
+      for (i = objfile->minimal_symbol_count; i > 0; i--)
+	{
+	  struct minimal_symbol *msym = &objfile->msymbols[i];
+	  const char *name = SYMBOL_LINKAGE_NAME (msym);
+
+	  /* If the minimal symbols whose name are prefixed by "__imp_"
+	     or "_imp_", get rid of the prefix, and search the minimal
+	     symbol in OBJFILE.  Note that 'maintenance print msymbols'
+	     shows that type of these "_imp_XXXX" symbols is mst_data.  */
+	  if (MSYMBOL_TYPE (msym) == mst_data
+	      && (strncmp (name, "__imp_", 6) == 0
+		  || strncmp (name, "_imp_", 5) == 0))
+	    {
+	      const char *name1 = (name[1] == '_' ? &name[7] : &name[6]);
+	      struct minimal_symbol *found;
+
+	      found = lookup_minimal_symbol (name1, NULL, objfile);
+	      /* If found, there are symbols named "_imp_foo" and "foo"
+		 respectively in OBJFILE.  Set the type of symbol "foo"
+		 as 'mst_solib_trampoline'.  */
+	      if (found != NULL && MSYMBOL_TYPE (found) == mst_text)
+		MSYMBOL_TYPE (found) = mst_solib_trampoline;
+	    }
+	}
+    }
+
   /* Free the installed minimal symbol data.  */
   do_cleanups (cleanup_minimal_symbols);
 
-- 
1.7.7.6