add gcc/gdb interface files

The gcc plugin is split into two parts.  One part is an ordinary gcc
plugin.  The other part is a shared library that is loaded by gdb.

This patch adds some files that define the interface exported by this
shared library to gdb.  These files also define the internal API by
which the gdb- and gcc-sides communicate.

These files will be kept in sync between gcc and gdb like much of
include/.

The exported API has been intentionally kept very simple.  In
particular only a single function is exported from the gdb-side
library; symbol visibility is used to hide everything else.  This
exported symbol is a function which is called to return a structure
holding function pointers that gdb then uses.  This structure is
versioned so that changes can be made without necessarily requiring a
simultaneous gdb upgrade.

Note that the C compiler API is broken out separately.  This lets us
extend it to other GCC front ends as desired.  We plan to investigate
C++ in the future.

include/ChangeLog
2014-12-12  Phil Muldoon  <pmuldoon@redhat.com>
	    Jan Kratochvil  <jan.kratochvil@redhat.com>
	    Tom Tromey  <tromey@redhat.com>

	* gcc-c-fe.def: New file.
	* gcc-c-interface.h: New file.
	* gcc-interface.h: New file.

1 files changed, 127 insertions, 0 deletions

diff --git a/include/gcc-interface.h b/include/gcc-interface.h
new file mode 100644
index 00000000000..34010f24704
--- /dev/null
+++ b/include/gcc-interface.h
@@ -0,0 +1,127 @@
+/* Generic interface between GCC and GDB
+
+   Copyright (C) 2014 Free Software Foundation, Inc.
+
+   This file is part of GCC.
+
+   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 GCC_INTERFACE_H
+#define GCC_INTERFACE_H
+
+/* This header defines the interface to the GCC API.  It must be both
+   valid C and valid C++, because it is included by both programs.  */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Opaque typedefs for objects passed through the interface.  */
+
+typedef unsigned long long gcc_type;
+typedef unsigned long long gcc_decl;
+
+/* An address in the inferior.  */
+
+typedef unsigned long long gcc_address;
+
+/* Forward declaration.  */
+
+struct gcc_base_context;
+
+/* Defined versions of the generic API.  */
+
+enum gcc_base_api_version
+{
+  GCC_FE_VERSION_0 = 0
+};
+
+/* The operations defined by the GCC base API.  This is the vtable for
+   the real context structure which is passed around.
+
+   The "base" API is concerned with basics shared by all compiler
+   front ends: setting command-line arguments, the file names, etc.
+
+   Front-end-specific interfaces inherit from this one.  */
+
+struct gcc_base_vtable
+{
+  /* The actual version implemented in this interface.  This field can
+     be relied on not to move, so users can always check it if they
+     desire.  The value is one of the gcc_base_api_version constants.
+  */
+
+  unsigned int version;
+
+  /* Set the compiler's command-line options for the next compilation.
+     TRIPLET_REGEXP is a regular expression that is used to match the
+     configury triplet prefix to the compiler.
+     The arguments are copied by GCC.  ARGV need not be
+     NULL-terminated.  The arguments must be set separately for each
+     compilation; that is, after a compile is requested, the
+     previously-set arguments cannot be reused.
+
+     This returns NULL on success.  On failure, returns a malloc()d
+     error message.  The caller is responsible for freeing it.  */
+
+  char *(*set_arguments) (struct gcc_base_context *self,
+			  const char *triplet_regexp,
+			  int argc, char **argv);
+
+  /* Set the file name of the program to compile.  The string is
+     copied by the method implementation, but the caller must
+     guarantee that the file exists through the compilation.  */
+
+  void (*set_source_file) (struct gcc_base_context *self, const char *file);
+
+  /* Set a callback to use for printing error messages.  DATUM is
+     passed through to the callback unchanged.  */
+
+  void (*set_print_callback) (struct gcc_base_context *self,
+			      void (*print_function) (void *datum,
+						      const char *message),
+			      void *datum);
+
+  /* Perform the compilation.  FILENAME is the name of the resulting
+     object file.  VERBOSE can be set to cause GCC to print some
+     information as it works.  Returns true on success, false on
+     error.  */
+
+  int /* bool */ (*compile) (struct gcc_base_context *self,
+			     const char *filename,
+			     int /* bool */ verbose);
+
+  /* Destroy this object.  */
+
+  void (*destroy) (struct gcc_base_context *self);
+};
+
+/* The GCC object.  */
+
+struct gcc_base_context
+{
+  /* The virtual table.  */
+
+  const struct gcc_base_vtable *ops;
+};
+
+/* The name of the dummy wrapper function generated by gdb.  */
+
+#define GCC_FE_WRAPPER_FUNCTION "_gdb_expr"
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GCC_INTERFACE_H */