[PATCH 2/7] Add platform agnostic dynamic loading code.

[Sanjoy Das <sanjoy@playingwithpointers.com>]

gdb-dlfcn.h and gdb-dlfcn.c are added, which implement the (cross
platform) functions gdb_dlopen, gdb_dlsym and gdb_dlclose. They should
work correctly on POSIX and windows systems.

gdb/ChangeLog
	* gdb-dlfcn.h, gdb-dlfcn.c: New.
	* Makefile.in: Add gdb_dlcfn.c and gdb_dlcfn.h to the build system.
	* configure.ac, config.in: Check for -ldl and accordingly define HAVE_LIBDL.
---
 gdb/ChangeLog   |    6 ++++++
 gdb/Makefile.in |    6 +++---
 gdb/gdb-dlfcn.c |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
 gdb/gdb-dlfcn.h |   27 +++++++++++++++++++++++++++
 4 files changed, 85 insertions(+), 3 deletions(-)
 create mode 100644 gdb/gdb-dlfcn.c
 create mode 100644 gdb/gdb-dlfcn.h

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index e7844b8..639f1f7 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2011-08-09  Sanjoy Das  <sdas@igalia.com>
+
+	* gdb-dlfcn.h, gdb-dlfcn.c: New.
+    	* Makefile.in: Add gdb_dlcfn.c and gdb_dlcfn.h to the build
+	system.
+
 2011-08-09  Sanjoy Das	<sdas@igalia.com>
 
 	* Makefile.in: Add jit-reader.h.in to HFILES_WITH_SRCDIR,
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 1ace7b8..f614204 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -739,7 +739,7 @@ SFILES = ada-exp.y ada-lang.c ada-typeprint.c ada-valprint.c ada-tasks.c \
 	annotate.c common/signals.c copying.c dfp.c gdb.c inf-child.c \
 	regset.c sol-thread.c windows-termcap.c \
 	common/common-utils.c common/xml-utils.c \
-	common/ptid.c common/buffer.c
+	common/ptid.c common/buffer.c gdb-dlfcn.c
 
 LINTFILES = $(SFILES) $(YYFILES) $(CONFIG_SRCS) init.c
 
@@ -820,7 +820,7 @@ solib-darwin.h solib-ia64-hpux.h solib-spu.h windows-nat.h xcoffread.h \
 gnulib/extra/arg-nonnull.h gnulib/extra/c++defs.h gnulib/extra/warn-on-use.h \
 gnulib/stddef.in.h inline-frame.h \
 common/common-utils.h common/xml-utils.h common/buffer.h common/ptid.h \
-common/linux-osdata.h
+common/linux-osdata.h gdb-dlfcn.h
 
 # Header files that already have srcdir in them, or which are in objdir.
 
@@ -907,7 +907,7 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $(YYOBJ) \
 	target-descriptions.o target-memory.o xml-tdesc.o xml-builtin.o \
 	inferior.o osdata.o gdb_usleep.o record.o gcore.o \
 	jit.o progspace.o \
-	common-utils.o buffer.o ptid.o
+	common-utils.o buffer.o ptid.o gdb-dlfcn.o
 
 TSOBS = inflow.o
 
diff --git a/gdb/gdb-dlfcn.c b/gdb/gdb-dlfcn.c
new file mode 100644
index 0000000..91e8a22
--- /dev/null
+++ b/gdb/gdb-dlfcn.c
@@ -0,0 +1,49 @@
+#include "gdb-dlfcn.h"
+
+#include "config.h"
+
+#ifdef HAVE_LIBDL
+#include <dlfcn.h>
+#elif __MINGW32__
+#include <windows.h>
+#else
+/* Unsupported configuration.  See Eg. gdb_dlopen for details.  */
+#error API to load shared library missing (Eg. libdl)
+#endif
+
+/* Load the dynamic library file named FILENAME, and return a handle
+   for that dynamic library.  Return NULL if the loading fails for
+   any reason.  */
+
+void *
+gdb_dlopen (const char *filename)
+{
+#ifdef HAVE_LIBDL
+  return dlopen (filename, RTLD_NOW);
+#elif __MINGW32__
+  return (void *) LoadLibrary (filename);
+#endif
+}
+
+/* Return the address of the symbol named SYMBOL inside the shared library
+   whose handle is HANDLE.  Return NULL when the symbol could not be found.  */
+
+void *
+gdb_dlsym (void *handle, const char *symbol)
+{
+#ifdef HAVE_LIBDL
+  return dlsym (handle, symbol);
+#elif __MINGW32__
+  return (void *) GetProcAddress (handle, symbol);
+#endif
+}
+
+int
+gdb_dlclose (void *handle)
+{
+#ifdef HAVE_LIBDL
+  return dlclose (handle);
+#elif __MINGW32__
+  return (int) FreeLibrary (handle);
+#endif
+}
diff --git a/gdb/gdb-dlfcn.h b/gdb/gdb-dlfcn.h
new file mode 100644
index 0000000..0d7b111
--- /dev/null
+++ b/gdb/gdb-dlfcn.h
@@ -0,0 +1,27 @@
+/* JIT declarations for GDB, the GNU Debugger.
+
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef GDB_DLFCN_H
+#define GDB_DLFCN_H
+
+void *gdb_dlopen (const char *filename);
+void *gdb_dlsym (void *handle, const char *symbol);
+int gdb_dlclose (void *handle);
+
+#endif /* GDB_DLFCN_H */
-- 
1.7.5.4