C++ compile support

This patch adds *basic* support for C++ to the compile feature.  It does
most simple type conversions, including everything that C compile does and
your basic "with-classes" type of C++.

I've written a new compile-support.exp support file which adds a new test
facility for automating and simplifying "compile print" vs "compile code"
testing.  See testsuite/lib/compile-support.exp and CompileExpression
for more on that.  The tests use this facility extensively.

This initial support has several glaring omissions:
- No template support at all
  I have follow-on patches for this, but they add much complexity
  to this "basic" support.  Consequently, they will be submitted separately.
- Cannot print functions
  The code template needs tweaking, and I simply haven't gotten to it yet.
- So-called "special function" support is not included
  Using constructors, destructors, operators, etc will not work. I have
  follow-on patches for that, but they require some work because of the
  recent churn in symbol searching.
- There are several test suite references to "compile/1234" bugs.
  I will file bugs and update the test suite's bug references before pushing
  these patches.

The test suite started as a copy of the original C-language support, but
I have written tests to exercise the basic functionality of the plug-in.

I've added a new option for outputting debug messages for C++ type-conversion
("debug compile-cplus-types").

gdb/ChangeLog:

	* Makefile.in (SUBDIR_GCC_COMPILE_SRCS): Add compile-cplus-symbols.c
	and compile-cplus-types.c.
	(HFILES_NO_SRCDIR): Add gcc-cp-plugin.h.
	* c-lang.c (cplus_language_defn): Set C++ compile functions.
	* c-lang.h (cplus_get_compile_context, cplus_compute_program):
	Declare.
	* compile/compile-c-support.c: Include compile-cplus.h.
	(load_libcompile): Templatize.
	(get_compile_context): "New" function.
	(c_get_compile_context): Use get_compile_context.
	(cplus_get_compile_context): New function.
	(cplus_push_user_expression, cplus_pop_user_expression)
	(cplus_add_code_header, cplus_add_input, cplus_compile_program)
	(cplus_compute_program): Define new structs/functions.
	* compile/compile-cplus-symmbols.c: New file.
	* compile/compile-cplus-types.c: New file.
	* compile/compile-cplus.h: New file.
	* compile/compile-internal.h (debug_compile_oracle, GCC_TYPE_NONE):
	Declare.
	* compile/compile-object-load.c (get_out_value_type): Use
	strncmp_iw when comparing symbol names.
	(compile_object_load): Add mst_bss and mst_data.
	* compile/compile.c (_initialize_compile): Remove
	-Wno-implicit-function-declaration from `compile_args'.
	* compile/gcc-cp-plugin.h: New file.
	* NEWS: Mention C++ compile support and new debug options.

gdb/testsuite/ChangeLog:

	* gdb.compile/compile-cplus-anonymous.cc: New file.
	* gdb.compile/compile-cplus-anonymous.exp: New file.
	* gdb.compile/compile-cplus-array-decay.cc: New file.
	* gdb.compile/compile-cplus-array-decay.exp: New file.
	* gdb.compile/compile-cplus-inherit.cc: New file.
	* gdb.compile/compile-cplus-inherit.exp: New file.
	* gdb.compile/compile-cplus-member.cc: New file.
	* gdb.compile/compile-cplus-member.exp: New file.
	* gdb.compile/compile-cplus-method.cc: New file.
	* gdb.compile/compile-cplus-method.exp: New file.
	* gdb.compile/compile-cplus-mod.c: "New" file.
	* gdb.compile/compile-cplus-namespace.cc: New file.
	* gdb.compile/compile-cplus-namespace.exp: New file.
	* gdb.compile/compile-cplus-nested.cc: New file.
	* gdb.compile/compile-cplus-nested.exp: New file.
	* gdb.compile/compile-cplus-print.c: "New" file.
	* gdb.compile/compile-cplus-print.exp: "New" file.
	* gdb.compile/compile-cplus-virtual.cc: New file.
	* gdb.compile/compile-cplus-virtual.exp: New file.
	* gdb.compile/compile-cplus.c: "New" file.
	* gdb.compile/compile-cplus.exp: "New" file.
	* lib/compile-support.exp: New file.

doc/ChangeLog:

	* gdb.texinfo (Compiling and injecting code in GDB): Document
	set/show "compile-oracle" and "compile-cplus-types" commands.

1 files changed, 85 insertions, 0 deletions

diff --git a/gdb/compile/gcc-cp-plugin.h b/gdb/compile/gcc-cp-plugin.h
new file mode 100644
index 0000000..1b72726
--- /dev/null
+++ b/gdb/compile/gcc-cp-plugin.h
@@ -0,0 +1,85 @@
+/* GCC C++ plug-in wrapper for GDB.
+
+   Copyright (C) 2018 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/>.  */
+
+/* A class representing the GCC C++ plug-in.  */
+
+#include "gcc-cp-interface.h"
+
+class gcc_cp_plugin
+{
+public:
+
+  explicit gcc_cp_plugin (struct gcc_cp_context *gcc_cp)
+    : m_context (gcc_cp)
+  {
+  }
+
+  /* Set the oracle callbacks to be used by the compiler plug-in.  */
+  void set_callbacks (gcc_cp_oracle_function *binding_oracle,
+		      gcc_cp_symbol_address_function *address_oracle,
+		      gcc_cp_enter_leave_user_expr_scope_function *enter_scope,
+		      gcc_cp_enter_leave_user_expr_scope_function *leave_scope,
+		      void *datum)
+  {
+    m_context->cp_ops->set_callbacks (m_context, binding_oracle,
+				      address_oracle, enter_scope, leave_scope,
+				      datum);
+  }
+
+  /* Returns the interface version of the compiler plug-in.  */
+  int version () const { return m_context->cp_ops->cp_version; }
+
+#define GCC_METHOD0(R, N) R N () const;
+#define GCC_METHOD1(R, N, A) R N (A) const;
+#define GCC_METHOD2(R, N, A, B) R N (A, B) const;
+#define GCC_METHOD3(R, N, A, B, C) R N (A, B, C) const;
+#define GCC_METHOD4(R, N, A, B, C, D) R N (A, B, C, D) const;
+#define GCC_METHOD5(R, N, A, B, C, D, E) R N (A, B, C, D, E) const;
+#define GCC_METHOD7(R, N, A, B, C, D, E, F, G) R N (A, B, C, D, E, F, G) const;
+
+#include "gcc-cp-fe.def"
+
+#undef GCC_METHOD0
+#undef GCC_METHOD1
+#undef GCC_METHOD2
+#undef GCC_METHOD3
+#undef GCC_METHOD4
+#undef GCC_METHOD5
+#undef GCC_METHOD7
+
+  /* Special overloads of plug-in methods with added debugging information.  */
+
+  gcc_expr build_decl (const char *debug_decltype, const char *name,
+		       enum gcc_cp_symbol_kind sym_kind, gcc_type sym_type,
+		       const char *substitution_name, gcc_address address,
+		       const char *filename, unsigned int line_number);
+
+  gcc_type start_class_type (const char *debug_name, gcc_decl typedecl,
+			     const struct gcc_vbase_array *base_classes,
+			     const char *filename, unsigned int line_number);
+
+  int finish_class_type (const char *debug_name, unsigned long size_in_bytes);
+
+  int pop_binding_level (const char *debug_name);
+
+private:
+
+  /* The GCC C++ context.  */
+  struct gcc_cp_context *m_context;
+};