* Makefile.in (c-lang.o, gnu-v3-abi.o): Update.

* NEWS: Mention improved C++ thunk support.
	* c-lang.c (cplus_language_defn): Mention cplus_skip_trampoline.
	* cp-abi.c (cplus_skip_trampoline): New.
	* cp-abi.h (cplus_skip_trampoline): New prototype.
	(struct cp_abi_ops): Add skip_trampoline member.
	* gnu-v3-abi.c (gnuv3_skip_trampoline): New.
	(init_gnuv3_ops): Set skip_trampoline.

	* gdb.cp/virtfunc.exp (proc do_tests): Test stepping through a thunk.

gdb/ChangeLog

@@ -1,3 +1,14 @@
+2007-05-07  Daniel Jacobowitz  <dan@codesourcery.com>
+
+	* Makefile.in (c-lang.o, gnu-v3-abi.o): Update.
+	* NEWS: Mention improved C++ thunk support.
+	* c-lang.c (cplus_language_defn): Mention cplus_skip_trampoline.
+	* cp-abi.c (cplus_skip_trampoline): New.
+	* cp-abi.h (cplus_skip_trampoline): New prototype.
+	(struct cp_abi_ops): Add skip_trampoline member.
+	* gnu-v3-abi.c (gnuv3_skip_trampoline): New.
+	(init_gnuv3_ops): Set skip_trampoline.
+
 2007-05-06  Daniel Jacobowitz  <dan@codesourcery.com>
 
 	* rs6000-tdep.c (struct frame_extra_info): Delete.

gdb/Makefile.in

@@ -1862,7 +1862,7 @@ charset.o: charset.c $(defs_h) $(charset_h) $(gdbcmd_h) $(gdb_assert_h) \
 c-lang.o: c-lang.c $(defs_h) $(symtab_h) $(gdbtypes_h) $(expression_h) \
 	$(parser_defs_h) $(language_h) $(c_lang_h) $(valprint_h) \
 	$(macroscope_h) $(gdb_assert_h) $(charset_h) $(gdb_string_h) \
-	$(demangle_h) $(cp_support_h)
+	$(demangle_h) $(cp_abi_h) $(cp_support_h)
 cli-out.o: cli-out.c $(defs_h) $(ui_out_h) $(cli_out_h) $(gdb_string_h) \
 	$(gdb_assert_h)
 coff-pe-read.o: coff-pe-read.c $(coff_pe_read_h) $(bfd_h) $(defs_h) \
@@ -2043,7 +2043,8 @@ gnu-v2-abi.o: gnu-v2-abi.c $(defs_h) $(gdb_string_h) $(symtab_h) \
 	$(gdbtypes_h) $(value_h) $(demangle_h) $(cp_abi_h) $(cp_support_h) \
 	$(gnu_v2_abi_h)
 gnu-v3-abi.o: gnu-v3-abi.c $(defs_h) $(value_h) $(cp_abi_h) $(cp_support_h) \
-	$(demangle_h) $(valprint_h) $(gdb_assert_h) $(gdb_string_h)
+	$(demangle_h) $(objfiles_h) $(valprint_h) \
+	$(gdb_assert_h) $(gdb_string_h)
 go32-nat.o: go32-nat.c $(defs_h) $(inferior_h) $(gdb_wait_h) $(gdbcore_h) \
 	$(command_h) $(gdbcmd_h) $(floatformat_h) $(buildsym_h) \
 	$(i387_tdep_h) $(i386_tdep_h) $(value_h) $(regcache_h) \

gdb/NEWS

@@ -29,6 +29,8 @@ iWMMXt coprocessor.
 ARM Windows CE (mingw32ce) debugging, and GDB Windows CE support
 has been rewritten to use the standard GDB remote protocol.
 
+* GDB can now step into C++ functions which are called through thunks.
+
 * New commands
 
 set mem inaccessible-by-default

gdb/c-lang.c

@@ -33,6 +33,7 @@
 #include "charset.h"
 #include "gdb_string.h"
 #include "demangle.h"
+#include "cp-abi.h"
 #include "cp-support.h"
 
 extern void _initialize_c_language (void);
@@ -642,7 +643,7 @@ const struct language_defn cplus_language_defn =
   c_print_type,			/* Print a type using appropriate syntax */
   c_val_print,			/* Print a value using appropriate syntax */
   c_value_print,		/* Print a top-level value */
-  NULL,				/* Language specific skip_trampoline */
+  cplus_skip_trampoline,	/* Language specific skip_trampoline */
   value_of_this,		/* value_of_this */
   cp_lookup_symbol_nonlocal,	/* lookup_symbol_nonlocal */
   cp_lookup_transparent_type,   /* lookup_transparent_type */

gdb/cp-abi.c

@@ -121,6 +121,14 @@ cplus_make_method_ptr (gdb_byte *contents, CORE_ADDR value, int is_virtual)
   (*current_cp_abi.make_method_ptr) (contents, value, is_virtual);
 }
 
+CORE_ADDR
+cplus_skip_trampoline (CORE_ADDR stop_pc)
+{
+  if (current_cp_abi.skip_trampoline == NULL)
+    return 0;
+  return (*current_cp_abi.skip_trampoline) (stop_pc);
+}
+
 struct value *
 cplus_method_ptr_to_value (struct value **this_p, struct value *method_ptr)
 {

gdb/cp-abi.h

@@ -170,6 +170,11 @@ struct value *cplus_method_ptr_to_value (struct value **this_p,
 void cplus_make_method_ptr (gdb_byte *CONTENTS, CORE_ADDR address,
 			    int is_virtual);
 
+/* Determine if we are currently in a C++ thunk.  If so, get the address
+   of the routine we are thunking to and continue to there instead.  */
+
+CORE_ADDR cplus_skip_trampoline (CORE_ADDR stop_pc);
+
 struct cp_abi_ops
 {
   const char *shortname;
@@ -192,6 +197,7 @@ struct cp_abi_ops
   int (*method_ptr_size) (void);
   void (*make_method_ptr) (gdb_byte *, CORE_ADDR, int);
   struct value * (*method_ptr_to_value) (struct value **, struct value *);
+  CORE_ADDR (*skip_trampoline) (CORE_ADDR);
 };
 
 

gdb/gnu-v3-abi.c

@@ -26,6 +26,7 @@
 #include "cp-abi.h"
 #include "cp-support.h"
 #include "demangle.h"
+#include "objfiles.h"
 #include "valprint.h"
 
 #include "gdb_assert.h"
@@ -673,6 +674,47 @@ gnuv3_method_ptr_to_value (struct value **this_p, struct value *method_ptr)
     return value_from_pointer (lookup_pointer_type (method_type), ptr_value);
 }
 
+/* Determine if we are currently in a C++ thunk.  If so, get the address
+   of the routine we are thunking to and continue to there instead.  */
+
+static CORE_ADDR 
+gnuv3_skip_trampoline (CORE_ADDR stop_pc)
+{
+  CORE_ADDR real_stop_pc, method_stop_pc;
+  struct minimal_symbol *thunk_sym, *fn_sym;
+  struct obj_section *section;
+  char *thunk_name, *fn_name;
+  
+  real_stop_pc = SKIP_TRAMPOLINE_CODE (stop_pc);
+  if (real_stop_pc == 0)
+    real_stop_pc = stop_pc;
+
+  /* Find the linker symbol for this potential thunk.  */
+  thunk_sym = lookup_minimal_symbol_by_pc (real_stop_pc);
+  section = find_pc_section (real_stop_pc);
+  if (thunk_sym == NULL || section == NULL)
+    return 0;
+
+  /* The symbol's demangled name should be something like "virtual
+     thunk to FUNCTION", where FUNCTION is the name of the function
+     being thunked to.  */
+  thunk_name = SYMBOL_DEMANGLED_NAME (thunk_sym);
+  if (thunk_name == NULL || strstr (thunk_name, " thunk to ") == NULL)
+    return 0;
+
+  fn_name = strstr (thunk_name, " thunk to ") + strlen (" thunk to ");
+  fn_sym = lookup_minimal_symbol (fn_name, NULL, section->objfile);
+  if (fn_sym == NULL)
+    return 0;
+
+  method_stop_pc = SYMBOL_VALUE_ADDRESS (fn_sym);
+  real_stop_pc = SKIP_TRAMPOLINE_CODE (method_stop_pc);
+  if (real_stop_pc == 0)
+    real_stop_pc = method_stop_pc;
+
+  return real_stop_pc;
+}
+
 static void
 init_gnuv3_ops (void)
 {
@@ -694,6 +736,7 @@ init_gnuv3_ops (void)
   gnu_v3_abi_ops.method_ptr_size = gnuv3_method_ptr_size;
   gnu_v3_abi_ops.make_method_ptr = gnuv3_make_method_ptr;
   gnu_v3_abi_ops.method_ptr_to_value = gnuv3_method_ptr_to_value;
+  gnu_v3_abi_ops.skip_trampoline = gnuv3_skip_trampoline;
 }
 
 extern initialize_file_ftype _initialize_gnu_v3_abi; /* -Wmissing-prototypes */

gdb/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2007-05-07  Daniel Jacobowitz  <dan@codesourcery.com>
+
+	* gdb.cp/virtfunc.exp (proc do_tests): Test stepping through a thunk.
+
 2007-05-06  Daniel Jacobowitz  <dan@codesourcery.com>
 
 	* gdb.fortran/complex.exp, gdb.fortran/complex.f: New files.

gdb/testsuite/gdb.cp/virtfunc.exp

@@ -254,6 +254,10 @@ proc do_tests {} {
     gdb_breakpoint test_calls
     gdb_test "continue" ".*Breakpoint .* test_calls.*" ""
     test_virtual_calls
+
+    gdb_test "next" ".*pAa->f.*" "next to pAa->f call"
+    gdb_test "next" ".*pDe->vg.*" "next to pDe->vg call"
+    gdb_test "step" ".*E::vg.*" "step through thunk into E::vg"
 }
 
 do_tests